ORCID Profile
0000-0002-8836-8947
Current Organisation
Garvan Institute of Medical Research
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Biochemistry and Cell Biology | Biochemistry and Cell Biology not elsewhere classified | Protein Trafficking | Cellular Interactions (Incl. Adhesion, Matrix, Cell Wall) | Cell Development (Incl. Cell Division And Apoptosis) | Genetic Technologies: Transformation, Site-Directed Mutagenesis, Etc. | Structural Biology (incl. Macromolecular Modelling) |
ANZSRC Socio-Economic Objective (SEO)
Reproductive System and Disorders | Immune system and allergy | Expanding Knowledge in the Biological Sciences | Cancer and Related Disorders | Blood disorders | Biological sciences | Infectious Diseases
Related Links
Publications
Discordance in STING-Induced Activation and Cell Death Between Mouse and Human Dendritic Cell Populations
Publisher: Frontiers Media SA
Date: 25-02-2022
DOI: 10.3389/FIMMU.2022.794776
Abstract: Stimulator of Interferon Genes (STING) is a cytosolic sensor of cyclic dinucleotides (CDNs). The activation of dendritic cells (DC) via the STING pathway, and their subsequent production of type I interferon (IFN) is considered central to eradicating tumours in mouse models. However, this contribution of STING in preclinical murine studies has not translated into positive outcomes of STING agonists in phase I & II clinical trials. We therefore questioned whether a difference in human DC responses could be critical to the lack of STING agonist efficacy in human settings. This study sought to directly compare mouse and human plasmacytoid DCs and conventional DC subset responses upon STING activation. We found all mouse and human DC subsets were potently activated by STING stimulation. As expected, Type I IFNs were produced by both mouse and human plasmacytoid DCs. However, mouse and human plasmacytoid and conventional DCs all produced type III IFNs (i.e., IFN-λs) in response to STING activation. Of particular interest, all human DCs produced large amounts of IFN-λ1, not expressed in the mouse genome. Furthermore, we also found differential cell death responses upon STING activation, observing rapid ablation of mouse, but not human, plasmacytoid DCs. STING-induced cell death in murine plasmacytoid DCs occurred in a cell-intrinsic manner and involved intrinsic apoptosis. These data highlight discordance between STING IFN and cell death responses in mouse and human DCs and caution against extrapolating STING-mediated events in mouse models to equivalent human outcomes.
Variability of Inducible Expression across the Hematopoietic System of Tetracycline Transactivator Transgenic Mice
Publisher: Public Library of Science (PLoS)
Date: 11-01-2013
Genomic subtyping and therapeutic targeting of acute erythroleukemia.
Publisher: Springer Science and Business Media LLC
Date: 29-03-2019
Cell cycle progression dictates the requirement for BCL2 in natural killer cell survival
Publisher: Rockefeller University Press
Date: 05-01-2017
DOI: 10.1084/JEM.20160869
Abstract: Natural killer (NK) cells are innate lymphoid cells with antitumor functions. Using an N-ethyl-N-nitrosourea (ENU)–induced mutagenesis screen in mice, we identified a strain with an NK cell deficiency caused by a hypomorphic mutation in the Bcl2 (B cell lymphoma 2) gene. Analysis of these mice and the conditional deletion of Bcl2 in NK cells revealed a nonredundant intrinsic requirement for BCL2 in NK cell survival. In these mice, NK cells in cycle were protected against apoptosis, and NK cell counts were restored in inflammatory conditions, suggesting a redundant role for BCL2 in proliferating NK cells. Consistent with this, cycling NK cells expressed higher MCL1 (myeloid cell leukemia 1) levels in both control and BCL2-null mice. Finally, we showed that deletion of BIM restored survival in BCL2-deficient but not MCL1-deficient NK cells. Overall, these data demonstrate an essential role for the binding of BCL2 to BIM in the survival of noncycling NK cells. They also favor a model in which MCL1 is the dominant survival protein in proliferating NK cells.
Homeostatic apoptosis prevents competition-induced atrophy in follicular B cells.
Publisher: Elsevier BV
Date: 07-2021
DOI: 10.1016/J.CELREP.2021.109430
Abstract: While the intrinsic apoptosis pathway is thought to play a central role in shaping the B cell lineage, its precise role in mature B cell homeostasis remains elusive. Using mice in which mature B cells are unable to undergo apoptotic cell death, we show that apoptosis constrains follicular B (FoB) cell lifespan but plays no role in marginal zone B (MZB) cell homeostasis. In these mice, FoB cells accumulate abnormally. This intensifies intercellular competition for BAFF, resulting in a contraction of the MZB cell compartment, and reducing the growth, trafficking, and fitness of FoB cells. Diminished BAFF signaling d ens the non-canonical NF-κB pathway, undermining FoB cell growth despite the concurrent triggering of a protective p53 response. Thus, MZB and FoB cells exhibit a differential requirement for the intrinsic apoptosis pathway. Homeostatic apoptosis constrains the size of the FoB cell compartment, thereby preventing competition-induced FoB cell atrophy.
Ablation of Type-1 IFN Signaling in Hematopoietic Cells Confers Protection Following Traumatic Brain Injury
Publisher: Society for Neuroscience
Date: 2016
Pharmacological inhibition of TBK1/IKKε blunts immunopathology in a murine model of SARS-CoV-2 infection
Publisher: Springer Science and Business Media LLC
Date: 18-09-2023
Point mutation in the gene encoding p300 suppresses thrombocytopenia in Mpl−/− mice
Publisher: American Society of Hematology
Date: 15-10-2008
DOI: 10.1182/BLOOD-2007-10-119677
Abstract: In an N-nitroso-N-ethylurea (ENU) mutagenesis screen using Mpl−/− mice, we isolated a semidominant suppressor of thrombocytopenia, termed Plt6. The gene mutated in Plt6 mice encodes the transcriptional coregulator p300, and the mutation, a tyrosine to asparagine substitution at amino acid 630 (Y630N), disrupts the interaction between p300 and c-Myb. Mpl−/−p300Plt6/+ mice displayed elevated platelet counts relative to Mpl−/−p300+/+ controls, whereas mice homozygous for the Plt6 mutation produced supraphysiological levels of circulating platelets. On a wild-type genetic background, mice homozygous for the p300Plt6 mutation, or recipients of Mpl+/+p300Plt6/Plt6 bone marrow, also exhibited thrombocytosis as well as deficiencies in B-lymphoid cells. Increased platelet numbers in Plt6 mutant mice were accompanied by significant increases in megakaryocyte progenitor cells within the bone marrow and spleen with concomitantly elevated numbers of megakaryocytes. The expansion of megakaryocytopoiesis and suppression of Mpl−/− thrombocytopenia in Plt6 mutants is highly reminiscent of that observed in mice with mutations affecting the p300 partner protein c-Myb, suggesting an indispensable repressive role for the c-Myb 300 transcriptional regulatory complex in megakaryocyte develop-ment, the inhibition of which allows substantial thrombopoietin (TPO)–independent platelet production.
Apoptosis in megakaryocytes and platelets: the life and death of a lineage
Publisher: American Society of Hematology
Date: 08-02-2018
DOI: 10.1182/BLOOD-2017-11-742684
Abstract: Despite their profoundly different cellular composition, size, and function, megakaryocytes and platelets both depend on restraint of the intrinsic (or “mitochondrial”) apoptosis pathway by BCL-2 family prosurvival proteins for their development and viability. Activation of the pathway contributes to the clearance of megakaryocytes following platelet shedding and constrains platelet lifespan in the circulation. Important questions remain as to how apoptosis is initiated in these cells at steady state and in response to pathophysiological insults.
Critical roles for c-Myb in lymphoid priming and early B-cell development
Publisher: American Society of Hematology
Date: 08-04-2010
DOI: 10.1182/BLOOD-2009-08-239210
Abstract: c-Myb is a transcription factor with functions in many hematopoietic lineages. c-Myb–deficient mice display reduced numbers of B cells however, it is unknown what role c-Myb plays in B lymphopoiesis because no critical target genes have been identified in the B-cell lineage. We demonstrate that conditional deletion of c-Myb in B-cell progenitors completely abolishes B-cell development. c-Myb is required for lymphoid progenitors to respond to the cytokines interleukin-7 and thymic stromal lymphopoietin in the absence of sufficient c-Myb activity, mice display a B lymphopenia that closely resembles that observed in interleukin-7 receptor α–deficient animals. Analysis of the multipotent progenitor compartment indicates that c-Myb is also required for up-regulation of multiple lymphoid-associated genes, including Il7r, and for the subsequent development of the common lymphoid progenitor population. These data show that c-Myb plays a critical role in the regulatory pathways governing lymphoid specification and early B-cell differentiation.
Shared roles for Scl and Lyl1 in murine platelet production and function
Publisher: American Society of Hematology
Date: 05-09-2019
Abstract: The stem cell leukemia (Scl or Tal1) protein forms part of a multimeric transcription factor complex required for normal megakaryopoiesis. However, unlike other members of this complex such as Gata1, Fli1, and Runx1, mutations of Scl have not been observed as a cause of inherited thrombocytopenia. We postulated that functional redundancy with its closely related family member, lymphoblastic leukemia 1 (Lyl1) might explain this observation. To determine whether Lyl1 can substitute for Scl in megakaryopoiesis, we examined the platelet phenotype of mice lacking 1 or both factors in megakaryocytes. Conditional Scl knockout (KO) mice crossed with transgenic mice expressing Cre recombinase under the control of the mouse platelet factor 4 (Pf4) promoter generated megakaryocytes with markedly reduced but not absent Scl. These Pf4Sclc-KO mice had mild thrombocytopenia and subtle defects in platelet aggregation. However, Pf4Sclc-KO mice generated on an Lyl1-null background (double knockout [DKO] mice) had severe macrothrombocytopenia, abnormal megakaryocyte morphology, defective pro-platelet formation, and markedly impaired platelet aggregation. DKO megakaryocytes, but not single-knockout megakaryocytes, had reduced expression of Gata1, Fli1, Nfe2, and many other genes that cause inherited thrombocytopenia. These gene expression changes were significantly associated with shared Scl and Lyl1 E-box binding sites that were also enriched for Gata1, Ets, and Runx1 motifs. Thus, Scl and Lyl1 share functional roles in platelet production by regulating expression of partner proteins including Gata1. We propose that this functional redundancy provides one explanation for the absence of Scl and Lyl1 mutations in inherited thrombocytopenia.
BCL-2 is dispensable for thrombopoiesis and platelet survival
Publisher: Springer Science and Business Media LLC
Date: 16-04-2015
Abstract: Navitoclax (ABT-263), an inhibitor of the pro-survival BCL-2 family proteins BCL-2, BCL-X L and BCL-W, has shown clinical efficacy in certain BCL-2-dependent haematological cancers, but causes dose-limiting thrombocytopaenia. The latter effect is caused by Navitoclax directly inducing the apoptotic death of platelets, which are dependent on BCL-X L for survival. Recently, ABT-199, a selective BCL-2 antagonist, was developed. It has shown promising anti-leukaemia activity in patients whilst sparing platelets, suggesting that the megakaryocyte lineage does not require BCL-2. In order to elucidate the role of BCL-2 in megakaryocyte and platelet survival, we generated mice with a lineage-specific deletion of Bcl2 , alone or in combination with loss of Mcl1 or Bclx . Platelet production and platelet survival were analysed. Additionally, we made use of BH3 mimetics that selectively inhibit BCL-2 or BCL-X L . We show that the deletion of BCL-2, on its own or in concert with MCL-1, does not affect platelet production or platelet lifespan. Thrombocytopaenia in Bclx -deficient mice was not affected by additional genetic loss or pharmacological inhibition of BCL-2. Thus, BCL-2 is dispensable for thrombopoiesis and platelet survival in mice.
Apoptotic Ablation of Platelets Reduces Atherosclerosis in Mice With Diabetes
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-2021
DOI: 10.1161/ATVBAHA.120.315369
Abstract: People with diabetes are at a significantly higher risk of cardiovascular disease, in part, due to accelerated atherosclerosis. Diabetic subjects have increased number of platelets that are activated, more reactive, and respond suboptimally to antiplatelet therapies. We hypothesized that reducing platelet numbers by inducing their premature apoptotic death would decrease atherosclerosis. This was achieved by targeting the antiapoptotic protein Bcl-x L (B-cell lymphoma-extra large which is essential for platelet viability) via distinct genetic and pharmacological approaches. In the former, we transplanted bone marrow from mice carrying the Tyr15 to Cys loss of function allele of Bcl-x (known as Bcl-x Plt20 ) or wild-type littermate controls into atherosclerotic-prone Ldlr +/− mice made diabetic with streptozotocin and fed a Western diet. Reduced Bcl-x L function in hematopoietic cells significantly decreased platelet numbers, exclusive of other hematologic changes. This led to a significant reduction in atherosclerotic lesion formation in Bcl-x Plt20 bone marrow transplanted Ldlr +/− mice. To assess the potential therapeutic relevance of reducing platelets in atherosclerosis, we next targeted Bcl-x L with a pharmacological strategy. This was achieved by low-dose administration of the BH3 (B-cell lymphoma-2 homology domain 3) mimetic, ABT-737 triweekly, in diabetic Apoe −/− mice for the final 6 weeks of a 12-week study. ABT-737 normalized platelet numbers along with platelet and leukocyte activation to that of nondiabetic controls, significantly reducing atherosclerosis while promoting a more stable plaque phenotype. These studies suggest that selectively reducing circulating platelets, by targeting Bcl-x L to promote platelet apoptosis, can reduce atherosclerosis and lower cardiovascular disease risk in diabetes. A graphic abstract is available for this article.
Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541173.V1
Abstract: Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541170.V1
Abstract: Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
ABCA12 Regulates ABCA1-Dependent Cholesterol Efflux from Macrophages and the Development of Atherosclerosis
Publisher: Elsevier BV
Date: 08-2013
DOI: 10.1016/J.CMET.2013.07.003
Abstract: ABCA12 is involved in the transport of ceramides in skin, but it may play a wider role in lipid metabolism. We show that, in Abca12-deficient macrophages, cholesterol efflux failed to respond to activation with LXR agonists. Abca12 deficiency caused a reduction in the abundance of Abca1, Abcg1, and Lxrβ. Overexpression of Lxrβ reversed the effects. Mechanistically, Abca12 deficiency did not affect expression of genes involved in cholesterol metabolism. Instead, a physical association between Abca1, Abca12, and Lxrβ proteins was established. Abca12 deficiency enhanced interaction between Abca1 and Lxrβ and the degradation of Abca1. Overexpression of ABCA12 in HeLa-ABCA1 cells increased the abundance and stability of ABCA1. Abca12 deficiency caused an accumulation of cholesterol in macrophages and the formation of foam cells, impaired reverse cholesterol transport in vivo, and increased the development of atherosclerosis in irradiated Apoe(-/-) mice reconstituted with Apoe(-/-)Abca12(-/-) bone marrow. Thus, ABCA12 regulates the cellular cholesterol metabolism via an LXRβ-dependent posttranscriptional mechanism.
Acknowledgements: the Levin/Kile rule
Publisher: Informa UK Limited
Date: 17-02-2019
Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541182
Abstract: Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Apoptotic Processes in Megakaryocytes and Platelets
Publisher: Elsevier BV
Date: 07-2010
DOI: 10.1053/J.SEMINHEMATOL.2010.03.006
Abstract: It is becoming increasingly clear that most mammalian cells are capable of undergoing apoptosis and that, within particular lineages, specific apoptotic pathways have evolved to regulate survival and turnover. The role of apoptosis in the megakaryocyte lineage is an intriguing one. Various insults, such as chemotherapeutics, autoantibodies, and human immunodeficiency virus (HIV), have been suggested to induce the apoptotic death of megakaryocytes and/or their progenitors. Conversely, apoptotic processes have been implicated in megakaryocyte development and platelet production. Platelets also contain functional apoptotic pathways, which circumscribe their survival. It has even been suggested that platelet activation responses involve components of the apoptotic machinery, highlighting a potential role for apoptotic processes in hemostasis and thrombosis. This review discusses the current state of knowledge about how apoptosis and apoptotic proteins contribute to the generation and function of megakaryocytes and platelets.
Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541188
Abstract: Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541185
Abstract: Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Loss of PUMA (BBC3) does not prevent thrombocytopenia caused by the loss of BCL-XL (BCL2L1).
Publisher: Wiley
Date: 25-05-2016
DOI: 10.1111/BJH.14155
Abstract: Apoptosis is required to maintain tissue homeostasis in multicellular organisms. Platelets, the anucleate cells that are essential for blood clotting, are a prime ex le. Their brief life span in the circulation is regulated by the intrinsic apoptosis pathway. Pro-survival BCL-XL (also termed BCL2L1) is essential for platelet viability. It functions to restrain the pro-apoptotic BCL-2 family members BAK (also termed BAK1) and BAX, the essential mediators of intrinsic apoptosis. Genetic deletion or pharmacological inhibition of BCL-XL results in thrombocytopenia. Conversely, deletion of BAK in platelets doubles their circulating life span. However, what triggers platelet apoptosis in vivo remains unclear. The pro-apoptotic BH3-only proteins are essential for initiating apoptosis in nucleated cells, and there is some evidence to suggest they also play a role in platelet biology. We investigated whether PUMA (also termed BBC3), a potent BH3-only protein that can inhibit all pro-survival BCL-2 family members as well as directly activate BAX, regulates the death of platelets. Surprisingly, loss of PUMA had no impact on the loss of platelets caused by loss of BCL-XL. It therefore remains to be established whether other BH3-only proteins play a critical role in induction of apoptosis in platelets or whether their death is controlled solely by the interactions between BCL-XL with BAK and BAX.
Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541167.V1
Abstract: Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
A missense mutation in the MLKL brace region promotes lethal neonatal inflammation and hematopoietic dysfunction
Publisher: Springer Science and Business Media LLC
Date: 19-06-2020
DOI: 10.1038/S41467-020-16819-Z
Abstract: MLKL is the essential effector of necroptosis, a form of programmed lytic cell death. We have isolated a mouse strain with a single missense mutation, Mlkl D139V , that alters the two-helix ‘brace’ that connects the killer four-helix bundle and regulatory pseudokinase domains. This confers constitutive, RIPK3 independent killing activity to MLKL. Homozygous mutant mice develop lethal postnatal inflammation of the salivary glands and mediastinum. The normal embryonic development of Mlkl D139V homozygotes until birth, and the absence of any overt phenotype in heterozygotes provides important in vivo precedent for the capacity of cells to clear activated MLKL. These observations offer an important insight into the potential disease-modulating roles of three common human MLKL polymorphisms that encode amino acid substitutions within or adjacent to the brace region. Compound heterozygosity of these variants is found at up to 12-fold the expected frequency in patients that suffer from a pediatric autoinflammatory disease, chronic recurrent multifocal osteomyelitis (CRMO).
Defective chromosome segregation, microtubule bundling and nuclear bridging in inner centromere protein gene (Incenp)-disrupted mice
Publisher: Oxford University Press (OUP)
Date: 07-1999
DOI: 10.1093/HMG/8.7.1145
Abstract: INCENP is a chromosomal passenger protein which relocates from the centromere to thel spindle midzone during the metaphase-anaphase transition, ultimately being discarded in the cell midbody at the completion of cytokinesis. Using homologous recombination, we have generated Incenp gene-targeted heterozygous mice that are phenotypically indistinguishable from their wild-type littermates. Intercrossing the hetero-zygotes results in no live-born homozygous Incenp -disrupted progeny, indicating an early lethality. Day 3.5 affected pre-implantation embryos contain large, morphologically abnormal cells that fail to fully develop a blastocoel cavity or thrive in utero and in culture. Chromatin and tubulin immunocytochemical stainings of these and day 2.5 affected embryos reveal a high mitotic index, no discernible metaphase or anaphase stages, complete absence of midbodies, micronuclei formation, morphologically irregular macronuclei with large chromosome complements, multipolar mitotic configurations, binucleated cells, internuclear bridges and abnormal spindle bundling. The phenotype is consistent with a defect in the modulation of microtubule dynamics, severely affecting chromosome segregation and resulting in poorly resolved chromatin masses, aberrant karyokinesis and internuclear bridge formation. These latter occurrences could pose a physical barrier blocking cytokinesis.
Negative Regulators of Cytokine Signaling
Publisher: Springer Science and Business Media LLC
Date: 04-2001
DOI: 10.1007/BF02981953
Transposon mutagenesis reveals cooperation of ETS family transcription factors with signaling pathways in erythro-megakaryocytic leukemia
Publisher: Proceedings of the National Academy of Sciences
Date: 26-03-2013
Abstract: To define genetic lesions driving leukemia, we targeted cre-dependent Sleeping Beauty (SB) transposon mutagenesis to the blood-forming system using a hematopoietic-selective vav 1 oncogene ( vav1 ) promoter. Leukemias of erse lineages ensued, most commonly lymphoid leukemia and erythroleukemia. The inclusion of a transgenic allele of Janus kinase 2 ( JAK2 ) V617F resulted in acceleration of transposon-driven disease and strong selection for erythroleukemic pathology with transformation of bipotential erythro-megakaryocytic cells. The genes encoding the E-twenty-six (ETS) transcription factors Ets related gene (Erg) and Ets1 were the most common sites for transposon insertion in SB-induced JAK2V617F -positive erythroleukemias, present in 87.5% and 65%, respectively, of independent leukemias examined. The role of activated Erg was validated by reproducing erythroleukemic pathology in mice transplanted with fetal liver cells expressing translocated in liposarcoma ( TLS ) -ERG , an activated form of ERG found in human leukemia. Via application of SB mutagenesis to TLS-ERG –induced erythroid transformation, we identified multiple loci as likely collaborators with activation of Erg . Jak2 was identified as a common transposon insertion site in TLS-ERG –induced disease, strongly validating the cooperation between JAK2V617F and transposon insertion at the Erg locus in the JAK2V617F -positive leukemias. Moreover, loci expressing other regulators of signal transduction pathways were conspicuous among the common transposon insertion sites in TLS-ERG –driven leukemia, suggesting that a key mechanism in erythroleukemia may be the collaboration of lesions disturbing erythroid maturation, most notably in genes of the ETS family, with mutations that reduce dependence on exogenous signals.
The EMT modulator SNAI1 contributes to AML pathogenesis via its interaction with LSD1
Publisher: American Society of Hematology
Date: 20-08-2020
Abstract: Modulators of epithelial-to-mesenchymal transition (EMT) have recently emerged as novel players in the field of leukemia biology. The mechanisms by which EMT modulators contribute to leukemia pathogenesis, however, remain to be elucidated. Here we show that overexpression of SNAI1, a key modulator of EMT, is a pathologically relevant event in human acute myeloid leukemia (AML) that contributes to impaired differentiation, enhanced self-renewal, and proliferation of immature myeloid cells. We demonstrate that ectopic expression of Snai1 in hematopoietic cells predisposes mice to AML development. This effect is mediated by interaction with the histone demethylase KDM1A/LSD1. Our data shed new light on the role of SNAI1 in leukemia development and identify a novel mechanism of LSD1 corruption in cancer. This is particularly pertinent given the current interest surrounding the use of LSD1 inhibitors in the treatment of multiple different malignancies, including AML.
Functional analysis of Asb-1 using genetic modification in mice.
Publisher: Informa UK Limited
Date: 09-2001
Workplace ageism: discovering hidden bias.
Publisher: Informa UK Limited
Date: 07-2013
Supplementary Figure from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541194
Abstract: Supplementary Figure from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Protein kinase R is an innate immune sensor of proteotoxic stress via accumulation of cytoplasmic IL-24.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 11-02-2022
DOI: 10.1126/SCIIMMUNOL.ABI6763
Abstract: Proteasome dysfunction can lead to autoinflammatory disease associated with elevated type I interferon (IFN-αβ) and NF-κB signaling however, the innate immune pathway driving this is currently unknown. Here, we identified protein kinase R (PKR) as an innate immune sensor for proteotoxic stress. PKR activation was observed in cellular models of decreased proteasome function and in multiple cell types from patients with proteasome-associated autoinflammatory disease (PRAAS). Furthermore, genetic deletion or small-molecule inhibition of PKR in vitro ameliorated inflammation driven by proteasome deficiency. In vivo, proteasome inhibitor-induced inflammatory gene transcription was blunted in PKR-deficient mice compared with littermate controls. PKR also acted as a rheostat for proteotoxic stress by triggering phosphorylation of eIF2α, which can prevent the translation of new proteins to restore homeostasis. Although traditionally known as a sensor of RNA, under conditions of proteasome dysfunction, PKR sensed the cytoplasmic accumulation of a known interactor, interleukin-24 (IL-24). When misfolded IL-24 egress into the cytosol was blocked by inhibition of the endoplasmic reticulum-associated degradation pathway, PKR activation and subsequent inflammatory signaling were blunted. Cytokines such as IL-24 are normally secreted from cells therefore, cytoplasmic accumulation of IL-24 represents an internal danger-associated molecular pattern. Thus, we have identified a mechanism by which proteotoxic stress is detected, causing inflammation observed in the disease PRAAS.
Fetal inhibition of inflammation improves disease phenotypes in Harlequin Ichthyosis.
Publisher: Oxford University Press (OUP)
Date: 10-09-2014
DOI: 10.1093/HMG/DDU459
Abstract: Harlequin ichthyosis (HI) is a severe skin disease which leads to neonatal death in ∼50% of cases. It is the result of mutations in ABCA12, a protein that transports lipids required to establish the protective skin barrier needed after birth. To better understand the life-threatening newborn HI phenotype, we analysed the developing epidermis for consequences of lipid dysregulation in mouse models. We observed a pro-inflammatory signature which was characterized by chemokine upregulation in embryonic skin which is distinct from that seen in other types of ichthyosis. Inflammation also persisted in grafted HI skin. To examine the contribution of inflammation to disease development, we overexpressed interleukin-37b to globally suppress fetal inflammation, observing considerable improvements in keratinocyte differentiation. These studies highlight inflammation as an unexpected contributor to HI disease development in utero, and suggest that inhibiting inflammation may reduce disease severity.
Programmed Anuclear Cell Death Delimits Platelet Life Span
Publisher: Elsevier BV
Date: 03-2007
DOI: 10.1016/J.CELL.2007.01.037
Abstract: Platelets are anuclear cytoplasmic fragments essential for blood clotting and wound healing. Despite much speculation, the factors determining their life span in the circulation are unknown. We show here that an intrinsic program for apoptosis controls platelet survival and dictates their life span. Pro-survival Bcl-x(L) constrains the pro-apoptotic activity of Bak to maintain platelet survival, but as Bcl-x(L) degrades, aged platelets are primed for cell death. Genetic ablation or pharmacological inactivation of Bcl-x(L) reduces platelet half-life and causes thrombocytopenia in a dose-dependent manner. Deletion of Bak corrects these defects, and platelets from Bak-deficient mice live longer than normal. Thus, platelets are, by default, genetically programmed to die by apoptosis. The antagonistic balance between Bcl-x(L) and Bak constitutes a molecular clock that determines platelet life span: this represents an important paradigm for cellular homeostasis, and has profound implications for the diagnosis and treatment of disorders that affect platelet number and function.
Association of coagulation factor XIII-A with Golgi proteins within monocyte-macrophages: implications for subcellular trafficking and secretion
Publisher: American Society of Hematology
Date: 04-2010
DOI: 10.1182/BLOOD-2009-08-231316
Abstract: Factor XIII-A (FXIII-A) is present in the cytosol of platelets, megakaryocytes, monocytes, osteoblasts, and macrophages and may be released from cells by a nonclassical pathway. We observed that plasma FXIII-A levels were unchanged in thrombocytopenic mice (Bcl-xPlt20/Plt20 and Mpl−/−), which implicates nonclassical secretion from nucleated cells as the source of plasma FXIII-A. We, therefore, examined the intracellular targeting of FXIII-A in the THP-1 (monocyte/macrophage) cell line and in human monocyte–derived macrophages. Metabolic labeling of THP-1 cells did not show release of 35S-FXIII-A either under basal conditions or when interleukin 1-β was released in response to cell stress. However, immunofluorescence of THP-1 cells and primary macrophages showed that FXIII-A associated with podosomes and other structures adjacent to the plasma membrane, which also contain trans-Golgi network protein-46 and Golgi matrix protein-130 (GM130) but not the endoplasmic reticulum luminal protein, protein disulphide isomerase. Further, FXIII-A was present in GM130-positive intracellular vesicles that could mediate its transport, and in other contexts GM130 and its binding partner GRASP have been implicated in the delivery of nonclassically secreted proteins to the plasma membrane. Hence, this mechanism may precede FXIII-A release into the extracellular matrix from macrophages and its release into plasma from the cell type of origin.
Trisomy of Erg is required for myeloproliferation in a mouse model of Down syndrome
Publisher: American Society of Hematology
Date: 13-05-2005
DOI: 10.1182/BLOOD-2009-09-242107
Abstract: Down syndrome is characterized by multiple phenotypic manifestations associated with trisomy of chromosome 21. The transient myeloproliferative disorder and acute megakaryocytic leukemia associated with Down syndrome are uniquely associated with mutations in the transcription factor GATA1 however, the identity of trisomic genes on chromosome 21 that predispose to these hematologic disorders remains unknown. Using a loss-of-function allele, we show that specific reduction to functional disomy of the Erg gene corrects the pathologic and hematologic features of myeloproliferation in the Ts(1716)65Dn mouse model of Down syndrome, including megakaryocytosis and progenitor cell expansion. Our data provide genetic evidence establishing the need for Erg trisomy for myeloproliferation in Ts(1716)65Dn mice and imply that increased ERG gene dosage may be a key consequence of trisomy 21 that can predispose to malignant hematologic disorders in Down syndrome.
NLRP1 restricts butyrate producing commensals to exacerbate inflammatory bowel disease
Publisher: Springer Science and Business Media LLC
Date: 13-09-2018
DOI: 10.1038/S41467-018-06125-0
Abstract: Anti-microbial signaling pathways are normally triggered by innate immune receptors when detecting pathogenic microbes to provide protective immunity. Here we show that the inflammasome sensor Nlrp1 aggravates DSS-induced experimental mouse colitis by limiting beneficial, butyrate-producing Clostridiales in the gut. The colitis-protective effects of Nlrp1 deficiency are thus reversed by vancomycin treatment, but recapitulated with butyrate supplementation in wild-type mice. Moreover, an activating mutation in Nlrp1a increases IL-18 and IFNγ production, and decreases colonic butyrate to exacerbate colitis. We also show that, in patients with ulcerative colitis, increased NLRP1 in inflamed regions of the colon is associated with increased IFN-γ . In this context, NLRP1 , IL-18 or IFN-γ expression negatively correlates with the abundance of Clostridiales in human rectal mucosal biopsies. Our data identify the NLRP1 inflammasome to be a key negative regulator of protective, butyrate-producing commensals, which therefore promotes inflammatory bowel disease.
Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541191
Abstract: Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Cloning, expression, and promoter structure of a mammalian Inner Centromere Protein (INCENP)
Publisher: Springer Science and Business Media LLC
Date: 04-1999
Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541164.V1
Abstract: Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Altered B-lymphopoiesis in mice with deregulated thrombopoietin signaling
Publisher: Springer Science and Business Media LLC
Date: 02-11-2017
DOI: 10.1038/S41598-017-15023-2
Abstract: Thrombopoietin (TPO) is the master cytokine regulator of megakaryopoiesis. In addition to regulation of megakaryocyte and platelet number, TPO is important for maintaining proper hematopoietic stem cell (HSC) function. It was previously shown that a number of lymphoid genes were upregulated in HSCs from Tpo −/− mice. We investigated if absent or enhanced TPO signaling would influence normal B-lymphopoiesis. Absent TPO signaling in Mpl −/− mice led to enrichment of a common lymphoid progenitor (CLP) signature in multipotential lineage-negative Sca-1 + c-Kit + (LSK) cells and an increase in CLP formation. Moreover, Mpl −/− mice exhibited increased numbers of PreB2 and immature B-cells in bone marrow and spleen, with an increased proportion of B-lymphoid cells in the G1 phase of the cell cycle. Conversely, elevated TPO signaling in Tpo Tg mice was associated with reduced B-lymphopoiesis. Although at steady state, peripheral blood lymphocyte counts were normal in both models, Mpl −/− Eµ- myc mice showed an enhanced preneoplastic phase with increased numbers of splenic PreB2 and immature B-cells, a reduced quiescent fraction, and augmented blood lymphocyte counts. Thus, although Mpl is not expressed on lymphoid cells, TPO signaling may indirectly influence B-lymphopoiesis and the preneoplastic state in Myc -driven B-cell lymphomagenesis by lineage priming in multipotential progenitor cells.
Suppressor of Cytokine Signaling 4 (SOCS4) Protects against Severe Cytokine Storm and Enhances Viral Clearance during Influenza Infection
Publisher: Public Library of Science (PLoS)
Date: 08-05-2014
CHD7 deficiency in Looper, a new mouse model of CHARGE syndrome, results in ossicle malformation, otosclerosis and hearing impairment
Publisher: Public Library of Science (PLoS)
Date: 19-05-2014
BAK/BAX macropores facilitate mitochondrial herniation and mtDNA efflux during apoptosis
Publisher: American Association for the Advancement of Science (AAAS)
Date: 23-02-2018
Abstract: Mitochondrial DNA (mtDNA) is a potent damage-associated molecular pattern that, if it reaches the cytoplasm or extracellular milieu, triggers innate immune pathways. mtDNA signaling has been implicated in a wide range of diseases however, the mechanisms of mtDNA release are unclear, and the process has not been observed in real time thus far. McArthur et al. used live-cell lattice light-sheet microscopy to look at mtDNA release during intrinsic apoptosis. Activation of the pro-death proteins BAK and BAX resulted in the formation of large macro-pores in the mitochondrial outer membrane. These massive holes caused the inner mitochondrial membrane to balloon out into the cytoplasm, resulting in mitochondrial herniation. This process allowed the contents of the mitochondrial matrix, including mtDNA, to escape into the cytoplasm. Science , this issue p. eaao6047
Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541191.V1
Abstract: Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Aberrant actin depolymerization triggers the pyrin inflammasome and autoinflammatory disease that is dependent on IL-18, not IL-1β
Publisher: Rockefeller University Press
Date: 25-05-2015
DOI: 10.1084/JEM.20142384
Abstract: Gain-of-function mutations that activate the innate immune system can cause systemic autoinflammatory diseases associated with increased IL-1β production. This cytokine is activated identically to IL-18 by an intracellular protein complex known as the inflammasome however, IL-18 has not yet been specifically implicated in the pathogenesis of hereditary autoinflammatory disorders. We have now identified an autoinflammatory disease in mice driven by IL-18, but not IL-1β, resulting from an inactivating mutation of the actin-depolymerizing cofactor Wdr1. This perturbation of actin polymerization leads to systemic autoinflammation that is reduced when IL-18 is deleted but not when IL-1 signaling is removed. Remarkably, inflammasome activation in mature macrophages is unaltered, but IL-18 production from monocytes is greatly exaggerated, and depletion of monocytes in vivo prevents the disease. Small-molecule inhibition of actin polymerization can remove potential danger signals from the system and prevents monocyte IL-18 production. Finally, we show that the inflammasome sensor of actin dynamics in this system requires caspase-1, apoptosis-associated speck-like protein containing a caspase recruitment domain, and the innate immune receptor pyrin. Previously, perturbation of actin polymerization by pathogens was shown to activate the pyrin inflammasome, so our data now extend this guard hypothesis to host-regulated actin-dependent processes and autoinflammatory disease.
Reduced Lymphocyte Longevity and Homeostatic Proliferation in Lamin B Receptor-Deficient Mice Results in Profound and Progressive Lymphopenia
Publisher: The American Association of Immunologists
Date: 2012
Abstract: The lamin B receptor (LBR) is a highly unusual inner nuclear membrane protein with multiple functions. Reduced levels are associated with decreased neutrophil lobularity, whereas complete absence of LBR results in severe skeletal dysplasia and in utero erinatal lethality. We describe a mouse pedigree, Lym3, with normal bone marrow and thymic development but profound and progressive lymphopenia particularly within the T cell compartment. This defect arises from a point mutation within the Lbr gene with only trace mutant protein detectable in homozygotes, albeit sufficient for normal development. Reduced T cell homeostatic proliferative potential and life span in vivo were found to contribute to lymphopenia. To investigate the role of LBR in gene silencing in hematopoietic cells, we examined gene expression in wild-type and mutant lymph node CD8 T cells and bone marrow neutrophils. Although LBR deficiency had a very mild impact on gene expression overall, for common genes differentially expressed in both LBR-deficient CD8 T cells and neutrophils, gene upregulation prevailed, supporting a role for LBR in their suppression. In summary, this study demonstrates that LBR deficiency affects not only nuclear architecture but also proliferation, cell viability, and gene expression of hematopoietic cells.
Apoptotic Caspases Suppress mtDNA-Induced STING-Mediated Type I IFN Production
Publisher: Elsevier BV
Date: 12-2014
Rotaxanes Capable of Recognising Chloride in Aqueous Media
Publisher: Wiley
Date: 28-10-2010
Abstract: A new, versatile chloride-anion-templating synthetic pathway is exploited for the preparation of a series of eight new [2]rotaxane host molecules, including the first sulfonamide interlocked system. (1)H NMR spectroscopic titration investigations demonstrate the rotaxanes' capability to selectively recognise the chloride anion in competitive aqueous solvent media. The interlocked host's halide binding affinity can be further enhanced and tuned through the attachment of electron-withdrawing substituents and by increasing its positive charge. A dicationic rotaxane selectively binds chloride in 35% water, wherein no evidence of oxoanion binding is observed. NMR spectroscopy, X-ray structural analysis and computational molecular dynamics simulations are used to account for rotaxane formation yields, anion binding strengths and selectivity trends.
Aging platelets stimulate TPO production
Publisher: Springer Science and Business Media LLC
Date: 2015
DOI: 10.1038/NM.3780
An essential role for α4A-tubulin in platelet biogenesis
Publisher: Life Science Alliance, LLC
Date: 02-2019
Abstract: During platelet biogenesis, microtubules (MTs) are arranged into submembranous structures (the marginal band) that encircle the cell in a single plane. This unique MT array has no equivalent in any other mammalian cell, and the mechanisms responsible for this particular mode of assembly are not fully understood. One possibility is that platelet MTs are composed of a particular set of tubulin isotypes that carry specific posttranslational modifications. Although β1-tubulin is known to be essential, no equivalent roles of α-tubulin isotypes in platelet formation or function have so far been reported. Here, we identify α4A-tubulin as a predominant α-tubulin isotype in platelets. Similar to β1-tubulin, α4A-tubulin expression is up-regulated during the late stages of megakaryocyte differentiation. Missense mutations in the α4A-tubulin gene cause macrothrombocytopenia in mice and humans. Defects in α4A-tubulin lead to changes in tubulin tyrosination status of the platelet tubulin pool. Ultrastructural defects include reduced numbers and misarranged MT coils in the platelet marginal band. We further observed defects in megakaryocyte maturation and proplatelet formation in Tuba4a -mutant mice. We have, thus, discovered an α-tubulin isotype with specific and essential roles in platelet biogenesis.
Mutational inhibition of c-Myb or p300 ameliorates treatment-induced thrombocytopenia
Publisher: American Society of Hematology
Date: 28-05-2009
DOI: 10.1182/BLOOD-2008-12-195255
Abstract: The transcription factor c-Myb and coregulator p300 have a key role in maintaining production of controlled numbers of megakaryocytes and platelets. In mice, mutations in c-Myb or p300 cause thrombocytosis in otherwise wild-type animals and can ameliorate the thrombocytopenia in mice lacking the thrombopoietin receptor, c-Mpl, a model for human congenital amegakaryocytic thrombocytopenia. To examine whether inhibition of c-Myb 300 is effective in other models of thrombocytopenia, the effect of the c-MybPlt4 mutation on thrombocytopenia associated with reduced platelet life span in Bcl-XPlt20/Plt20 mice was assessed, as were responses in c-MybPlt4 and/or p300Plt6 mutant mice to thrombocytopenia associated with antiplatelet antibodies, chemotherapy, or bone marrow transplantation. Homozygosity of the c-MybPlt4 allele ameliorated thrombocytopenia associated with reduced platelet life span, and c-MybPlt4/+ mice exhibited more rapid than normal recovery from thrombocytopenia caused by antiplatelet serum or bone marrow transplantation. Recovery to pretreatment platelet levels was unaltered in 5-fluorouracil–treated c-MybPlt4/+ mice relative to wild-type controls, but enhanced platelet production during subsequent thrombocytosis was evident. More modest enhancement of platelet recovery after 5-fluorouracil or bone marrow transplantation was also evident in p300Plt6/+ animals. The data suggest potential utility of c-Myb 300 as a target for therapeutic intervention in thrombocytopenia of erse origins.
Supplementary Figure from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541194.V1
Abstract: Supplementary Figure from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
The role of apoptosis in megakaryocytes and platelets
Publisher: Wiley
Date: 28-01-2014
DOI: 10.1111/BJH.12757
Abstract: The role of apoptotic pathways in the development and function of the megakaryocyte lineage has generated renewed interest in recent years. This has been driven by the advent of BH3 mimetic drugs that target BCL2 family proteins to induce apoptosis in tumour cells: agents such as ABT-263 (navitoclax, which targets BCL2, BCL-XL [BCL2L1] and BCL2L2) and ABT-199 (a BCL2-specific agent) are showing great promise in early stage clinical trials. However, the major dose-limiting toxicity of navitoclax has proven to be thrombocytopenia, an on-target effect of inhibiting BCL-XL . It transpires that the anucleate platelet contains a classical intrinsic apoptosis pathway, which at steady state regulates its life span in the circulation. BCL-XL is the critical pro-survival protein that restrains apoptosis and maintains platelet viability. These findings have paved the way to a deeper understanding of apoptotic pathways and processes in platelets, and their precursor cell, the megakaryocyte.
Interleukin-11 is the dominant IL-6 family cytokine during gastrointestinal tumorigenesis and can be targeted therapeutically.
Publisher: Elsevier BV
Date: 08-2013
DOI: 10.1016/J.CCR.2013.06.017
Abstract: Among the cytokines linked to inflammation-associated cancer, interleukin (IL)-6 drives many of the cancer "hallmarks" through downstream activation of the gp130/STAT3 signaling pathway. However, we show that the related cytokine IL-11 has a stronger correlation with elevated STAT3 activation in human gastrointestinal cancers. Using genetic mouse models, we reveal that IL-11 has a more prominent role compared to IL-6 during the progression of sporadic and inflammation-associated colon and gastric cancers. Accordingly, in these models and in human tumor cell line xenograft models, pharmacologic inhibition of IL-11 signaling alleviated STAT3 activation, suppressed tumor cell proliferation, and reduced the invasive capacity and growth of tumors. Our results identify IL-11 signaling as a potential therapeutic target for the treatment of gastrointestinal cancers.
Characterization of Tfrc-mutant mice with microcytic phenotypes
Publisher: American Society of Hematology
Date: 09-08-2018
DOI: 10.1182/BLOODADVANCES.2018018820
Abstract: Novel Tfrc-mutant mouse identified in ENU mutagenesis screen with stable receptor expression. Flow imaging cytometry demonstrates microcytosis in mutants derives from dysfunctional receptor-mediated endocytosis of Tf-TfR complex.
Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541188.V1
Abstract: Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Regulation of cell proliferation by ERK and signal-dependent nuclear translocation of ERK is dependent on Tm5NM1-containing actin filaments
Publisher: American Society for Cell Biology (ASCB)
Date: 07-2015
Abstract: ERK-regulated cell proliferation requires multiple phosphorylation events catalyzed first by MEK and then by casein kinase 2 (CK2), followed by interaction with importin7 and subsequent nuclear translocation of pERK. We report that genetic manipulation of a core component of the actin filaments of cancer cells, the tropomyosin Tm5NM1, regulates the proliferation of normal cells both in vitro and in vivo. Mouse embryo fibroblasts (MEFs) lacking Tm5NM1, which have reduced proliferative capacity, are insensitive to inhibition of ERK by peptide and small-molecule inhibitors, indicating that ERK is unable to regulate proliferation of these knockout (KO) cells. Treatment of wild-type MEFs with a CK2 inhibitor to block phosphorylation of the nuclear translocation signal in pERK resulted in greatly decreased cell proliferation and a significant reduction in the nuclear translocation of pERK. In contrast, Tm5NM1 KO MEFs, which show reduced nuclear translocation of pERK, were unaffected by inhibition of CK2. This suggested that it is nuclear translocation of CK2-phosphorylated pERK that regulates cell proliferation and this capacity is absent in Tm5NM1 KO cells. Proximity ligation assays confirmed a growth factor–stimulated interaction of pERK with Tm5NM1 and that the interaction of pERK with importin7 is greatly reduced in the Tm5NM1 KO cells.
Sex and strain-related differences in the peripheral blood cell values of inbred mouse strains
Publisher: Springer Science and Business Media LLC
Date: 2003
Bcl-xL–inhibitory BH3 mimetics can induce a transient thrombocytopathy that undermines the hemostatic function of platelets
Publisher: American Society of Hematology
Date: 11-08-2011
DOI: 10.1182/BLOOD-2011-04-347849
Abstract: BH3 mimetics are a new class of proapo-ptotic anticancer agents that have shown considerable promise in preclinical animal models and early-stage human trials. These agents act by inhibiting the pro-survival function of one or more Bcl-2–related proteins. Agents that inhibit Bcl-xL induce rapid platelet death that leads to thrombocytopenia however, their impact on the function of residual circulating platelets remains unclear. In this study, we demonstrate that the BH3 mimetics, ABT-737 or ABT-263, induce a time- and dose-dependent decrease in platelet adhesive function that correlates with ectodomain shedding of the major platelet adhesion receptors, glycoprotein Ibα and glycoprotein VI, and functional down-regulation of integrin αIIbβ3. Analysis of platelets from mice treated with higher doses of BH3 mimetics revealed the presence of a subpopulation of circulating platelets undergoing cell death that have impaired activation responses to soluble agonists. Functional analysis of platelets by intravital microscopy revealed a time-dependent defect in platelet aggregation at sites of vascular injury that correlated with an increase in tail bleeding time. Overall, these studies demonstrate that Bcl-xL–inhibitory BH3 mimetics not only induce thrombocytopenia but also a transient thrombocytopathy that can undermine the hemostatic function of platelets.
Erg is required for self-renewal of hematopoietic stem cells during stress hematopoiesis in mice
Publisher: American Society of Hematology
Date: 09-2011
DOI: 10.1182/BLOOD-2011-03-344739
Abstract: Hematopoietic stem cells (HSCs) are rare residents of the bone marrow responsible for the lifelong production of blood cells. Regulation of the balance between HSC self-renewal and differentiation is central to hematopoiesis, allowing precisely regulated generation of mature blood cells at steady state and expanded production at times of rapid need, as well as maintaining ongoing stem cell capacity. Erg, a member of the Ets family of transcription factors, is deregulated in cancers and although Erg is known to be required for regulation of adult HSCs, its precise role has not been defined. We show here that, although heterozygosity for functional Erg is sufficient for adequate steady-state HSC maintenance, Erg+/Mld2 mutant mice exhibit impaired HSC self-renewal after bone marrow transplantation or during recovery from myelotoxic stress. Moreover, although mice functionally compromised for either Erg or Mpl, the receptor for thrombopoietin, a key regulator of HSC quiescence, maintained sufficient HSC activity to sustain hematopoiesis, Mpl−/−Erg+/Mld2 compound mutant mice displayed exacerbated stem cell deficiencies and bone marrow failure. Thus, Erg is a critical regulator of adult HSCs, essential for maintaining self-renewal at times of high HSC cycling.
NLRP1 inflammasome activation induces pyroptosis of hematopoietic progenitor cells.
Publisher: Elsevier BV
Date: 12-2012
The spreading influence of platelet HDACs
Publisher: American Society of Hematology
Date: 15-11-2012
Data from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.C.6549562
Abstract: Abstract Pharmacologic inhibition of epigenetic enzymes can have therapeutic benefit against hematologic malignancies. In addition to affecting tumor cell growth and proliferation, these epigenetic agents may induce antitumor immunity. Here, we discovered a novel immunoregulatory mechanism through inhibition of histone deacetylases (HDAC). In models of acute myeloid leukemia (AML), leukemia cell differentiation and therapeutic benefit mediated by the HDAC inhibitor (HDACi) panobinostat required activation of the type I interferon (IFN) pathway. Plasmacytoid dendritic cells (pDC) produced type I IFN after panobinostat treatment, through transcriptional activation of IFN genes concomitant with increased H3K27 acetylation at these loci. Depletion of pDCs abrogated panobinostat-mediated induction of type I IFN signaling in leukemia cells and impaired therapeutic efficacy, whereas combined treatment with panobinostat and IFNα improved outcomes in preclinical models. These discoveries offer a new therapeutic approach for AML and demonstrate that epigenetic rewiring of pDCs enhances antitumor immunity, opening the possibility of exploiting this approach for immunotherapies. Significance: We demonstrate that HDACis induce terminal differentiation of AML through epigenetic remodeling of pDCs, resulting in production of type I IFN that is important for the therapeutic effects of HDACis. The study demonstrates the important functional interplay between the immune system and leukemias in response to HDAC inhibition. i This article is highlighted in the In This Issue feature, p. 1397 /i /
Connexin-dependent transfer of cgamp to phagocytes modulates antiviral responses
Publisher: American Society for Microbiology
Date: 25-02-2020
Abstract: Recent studies suggest that extracellular cGAMP can be taken up by macrophages to engage STING through several mechanisms. Our work demonstrates that connexin-dependent communication between epithelial cells and macrophages plays a significant role in the lification of antiviral responses mediated by cGAMP and suggests that pharmacological strategies aimed at modulating connexins may have therapeutic applications to control antiviral responses in humans.
The Dendritic Cell Receptor Clec9A Binds Damaged Cells via Exposed Actin Filaments
Publisher: Elsevier BV
Date: 04-2012
DOI: 10.1016/J.IMMUNI.2012.03.009
Abstract: The immune system must distinguish viable cells from cells damaged by physical and infective processes. The damaged cell-recognition molecule Clec9A is expressed on the surface of the mouse and human dendritic cell subsets specialized for the uptake and processing of material from dead cells. Clec9A recognizes a conserved component within nucleated and nonnucleated cells, exposed when cell membranes are damaged. We have identified this Clec9A ligand as a filamentous form of actin in association with particular actin-binding domains of cytoskeletal proteins. We have determined the crystal structure of the human CLEC9A C-type lectin domain and propose a functional dimeric structure with conserved tryptophans in the ligand recognition site. Mutation of these residues ablated CLEC9A binding to damaged cells and to the isolated ligand complexes. We propose that Clec9A provides targeted recruitment of the adaptive immune system during infection and can also be utilized to enhance immune responses generated by vaccines.
Platelet necrosis mediates ischemic stroke outcome in mice
Publisher: American Society of Hematology
Date: 06-02-2020
Abstract: Dysregulated platelet functions contribute to the development and progression of ischemic stroke. Utilizing mice with a platelet-specific deletion of cyclophilin D (CypD), a mediator of necrosis, we found that platelet necrosis regulates tissue damage and outcomes during ischemic stroke in vivo. Mice with loss of CypD in platelets (CypDplt−/−mice) exhibited significantly enhanced cerebral blood flow, improved neurological and motor functions, and reduced ischemic stroke infarct volume after cerebral ischemia-reperfusion injury. These effects were attributable, at least in part, to platelet-neutrophil interactions. Twenty-four hours after stroke, significantly more circulating platelet-neutrophil aggregates (PNAs) were found in CypDplt+/+ mice. Underscoring the role of platelet necrosis in PNA formation, we observed a significant number of phosphatidylserine (PS)+ platelets in PNAs in CypDplt+/+ mice. In contrast, significantly fewer platelets in PNAs were PS+ in CypDplt−/− counterparts. Accordingly, mice with CypD-deficient platelets had fewer neutrophils and PNAs recruited to their brain following stroke relative to wild-type counterparts. Neutrophil depletion in wild-type mice conferred protection from ischemic stroke to a similar degree as observed in mice with CypD-deficient platelets. Neutrophil depletion in CypDplt−/− mice did not further reduce infarct size. Transmission electron microscopy of ex vivo–formed PNAs revealed a propensity of necrotic platelets to interact with neutrophils. These results suggest that necrotic platelets interact with neutrophils to exacerbate brain injury during ischemic stroke. Because inhibiting platelet necrosis does not compromise hemostasis, targeting platelet CypD may be a potential therapeutic strategy to limit brain damage following ischemic stroke.
The role of the intrinsic apoptosis pathway in platelet life and death
Publisher: Elsevier BV
Date: 07-2009
DOI: 10.1111/J.1538-7836.2009.03366.X
Abstract: In recent years, it has become increasingly apparent that the production of platelets and their subsequent life span in the circulation are regulated, at least in part, by apoptotic mechanisms. There is also evidence implicating the apoptotic machinery in the regulation of platelet functional responses. This review examines the role of the intrinsic apoptosis pathway, regulated by the Bcl-2 family of proteins, in platelet biology.
ERG dependence distinguishes developmental control of hematopoietic stem cell maintenance from hematopoietic specification
Publisher: Cold Spring Harbor Laboratory
Date: 18-01-2011
DOI: 10.1101/GAD.2009211
Abstract: Although many genes are known to be critical for early hematopoiesis in the embryo, it remains unclear whether distinct regulatory pathways exist to control hematopoietic specification versus hematopoietic stem cell (HSC) emergence and function. Due to their interaction with key regulators of hematopoietic commitment, particular interest has focused on the role of the ETS family of transcription factors of these, ERG is predicted to play an important role in the initiation of hematopoiesis, yet we do not know if or when ERG is required. Using in vitro and in vivo models of hematopoiesis and HSC development, we provide strong evidence that ERG is at the center of a distinct regulatory program that is not required for hematopoietic specification or differentiation but is critical for HSC maintenance during embryonic development. We show that, from the fetal period, ERG acts as a direct upstream regulator of Gata2 and Runx1 gene activity. Without ERG, physiological HSC maintenance fails, leading to the rapid exhaustion of definitive hematopoiesis.
Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 21-03-2022
DOI: 10.1158/2159-8290.CD-20-1145
Abstract: We demonstrate that HDACis induce terminal differentiation of AML through epigenetic remodeling of pDCs, resulting in production of type I IFN that is important for the therapeutic effects of HDACis. The study demonstrates the important functional interplay between the immune system and leukemias in response to HDAC inhibition. This article is highlighted in the In This Issue feature, p. 1397
Mitochondrial apoptosis is dispensable for NLRP 3 inflammasome activation but non‐apoptotic caspase‐8 is required for inflammasome priming
Publisher: EMBO
Date: 02-07-2014
Abstract: A current paradigm proposes that mitochondrial damage is a critical determinant of NLRP 3 inflammasome activation. Here, we genetically assess whether mitochondrial signalling represents a unified mechanism to explain how NLRP 3 is activated by ergent stimuli. Neither co‐deletion of the essential executioners of mitochondrial apoptosis BAK and BAX , nor removal of the mitochondrial permeability transition pore component cyclophilin D, nor loss of the mitophagy regulator Parkin, nor deficiency in MAVS affects NLRP 3 inflammasome function. In contrast, caspase‐8, a caspase essential for death‐receptor‐mediated apoptosis, is required for efficient Toll‐like‐receptor‐induced inflammasome priming and cytokine production. Collectively, these results demonstrate that mitochondrial apoptosis is not required for NLRP 3 activation, and highlight an important non‐apoptotic role for caspase‐8 in regulating inflammasome activation and pro‐inflammatory cytokine levels.
Human erythroleukemia genetics and transcriptomes identify master transcription factors as functional disease drivers
Publisher: American Society of Hematology
Date: 06-08-2020
Abstract: Acute erythroleukemia (AEL or acute myeloid leukemia [AML]-M6) is a rare but aggressive hematologic malignancy. Previous studies showed that AEL leukemic cells often carry complex karyotypes and mutations in known AML-associated oncogenes. To better define the underlying molecular mechanisms driving the erythroid phenotype, we studied a series of 33 AEL s les representing 3 genetic AEL subgroups including TP53-mutated, epigenetic regulator-mutated (eg, DNMT3A, TET2, or IDH2), and undefined cases with low mutational burden. We established an erythroid vs myeloid transcriptome-based space in which, independently of the molecular subgroup, the majority of the AEL s les exhibited a unique mapping different from both non-M6 AML and myelodysplastic syndrome s les. Notably, & % of AEL patients, including in the genetically undefined subgroup, showed aberrant expression of key transcriptional regulators, including SKI, ERG, and ETO2. Ectopic expression of these factors in murine erythroid progenitors blocked in vitro erythroid differentiation and led to immortalization associated with decreased chromatin accessibility at GATA1-binding sites and functional interference with GATA1 activity. In vivo models showed development of lethal erythroid, mixed erythroid/myeloid, or other malignancies depending on the cell population in which AEL-associated alterations were expressed. Collectively, our data indicate that AEL is a molecularly heterogeneous disease with an erythroid identity that results in part from the aberrant activity of key erythroid transcription factors in hematopoietic stem or progenitor cells.
Loss of Dynamin 2 GTP ase function results in microcytic anaemia
Publisher: Wiley
Date: 03-05-2017
DOI: 10.1111/BJH.14709
Abstract: In a dominant mouse ethylnitrosurea mutagenesis screen for genes regulating erythropoiesis, we identified a pedigree with a novel microcytic hypochromia caused by a V235G missense mutation in Dynamin 2 (Dnm2). Mutations in Dnm2, a GTPase, are highly disease-specific and have been implicated in four forms of human diseases: centronuclear myopathy, Charcot-Marie Tooth neuropathy and, more recently, T-cell leukaemia and Hereditary Spastic Paraplegia, but red cell abnormalities have not been reported to date. The V235G mutation lies within a crucial GTP nucleotide-binding pocket of Dnm2, and resulted in defective GTPase activity and incompatibility with life in the homozygous state. Dnm2 is an essential mediator of clathrin-mediated endocytosis, which is required for the uptake of transferrin (Tf) into red cells for incorporation of haem. Accordingly, we observed significantly reduced Tf uptake by Dnm2
Probabilistic analysis of recessive mutagenesis screen strategies
Publisher: Springer Science and Business Media LLC
Date: 2007
DOI: 10.1007/S00335-006-0057-Z
Abstract: Random mutagenesis screens for recessive phenotypes require three generations of breeding, using either a backcross (BC) or intercross (IC) strategy. Hence, they are more costly and technically demanding than those for dominant phenotypes. Maximizing the return from these screens requires maximizing the number of mutations that are bred to homozyosity in the G(3) generation. Using a probabilistic approach, we compare different designs of screens for recessive phenotypes and the impact each one has on the number of mutations that can be effectively screened. We address the issue of BC versus IC strategies and consider genome-wide, region-specific screens and suppressor screens. We find that optimally designed BC and IC screens allow the screening of, on average, similar numbers of mutations but that interpedigree variation is more pronounced when the IC strategy is employed. By conducting a retrospective analysis of published mutagenesis screens, we show that, depending on the strategy, a threefold difference in the numbers of mutations screened per animal used could be expected. This method allows researchers to contrast, for a range of experimental designs, the cost per mutation screened and to maximize the number of mutations that one can expect to screen in a given experiment.
Epigenetic reprogramming of plasmacytoid dendritic cells drives type I interferon-dependent differentiation of acute myeloid leukemias for therapeutic benefit
Publisher: Cold Spring Harbor Laboratory
Date: 24-08-2020
DOI: 10.1101/2020.08.23.235499
Abstract: Pharmacological inhibition of epigenetic enzymes can have therapeutic benefit, particularly against hematological malignancies. While these agents can affect tumor cell growth and proliferation, recent studies have demonstrated that pharmacological de-regulation of epigenetic modifiers may additionally mediate anti-tumor immune responses. Here we discovered a novel mechanism of immune regulation through the inhibition of histone deacetylases (HDACs). In a genetically engineered model of t(8 ) AML, leukemia cell differentiation and therapeutic benefit mediated by the HDAC inhibitor panobinostat required activation of the type I interferon (IFN) signaling pathway. Plasmacytoid dendritic cells (pDCs) were identified as the cells producing type I IFN in response to panobinostat, through transcriptional activation of IFN genes concomitant with increased H3K27 acetylation at these loci. Depletion of pDCs abrogated panobinostat-mediated activation of type I IFN signaling in leukemia cells and impaired therapeutic efficacy, while combined treatment of panobinostat and recombinant IFNα improved therapeutic outcomes. These discoveries offer a new therapeutic approach for t(8 ) AML and demonstrate that epigenetic rewiring of pDCs enhances anti-tumor immunity, opening the possibility of exploiting this cell type as a new target for immunotherapy.
Loss of Bak enhances lymphocytosis but does not ameliorate thrombocytopaenia in BCL-2 transgenic mice
Publisher: Springer Science and Business Media LLC
Date: 24-01-2014
DOI: 10.1038/CDD.2013.201
Deciphering the molecular and biologic processes that mediate histone deacetylase inhibitor–induced thrombocytopenia
Publisher: American Society of Hematology
Date: 31-03-2011
DOI: 10.1182/BLOOD-2010-11-318055
Abstract: Histone deacetylase inhibitor (HDACI)–induced thrombocytopenia (TCP) is a major dose-limiting toxicity of this new class of drugs. Using preclinical models to study the molecular and biologic events that underpin this effect of HDACI, we found that C57BL/6 mice treated with both the HDAC1/2-selective HDACI romidepsin and the pan-HDACI panobinostat developed significant TCP. HDACI-induced TCP was not due to myelosuppression or reduced platelet lifespan, but to decreased platelet release from megakaryocytes. Cultured primary murine megakaryocytes showed reductions in proplatelet extensions after HDACI exposure and a dose-dependent increase in the phosphorylation of myosin light chain 2 (MLC2). Phosphorylation of MLC to phospho-MLC (pMLC) and subsequent proplatelet formation in megakaryocytes is regulated by the Rho-GTPase proteins Rac1, CDC42, and RhoA. Primary mouse megakaryocytes and the human megakaryoblastic cell line Meg-01 showed reductions in Rac1, CDC42, and RhoA protein levels after treatment with HDACIs. We were able to overcome HDACI-induced TCP by administering the mouse-specific thrombopoietin (TPO) mimetic AMP-4, which improved platelet numbers to levels similar to untreated controls. Our report provides the first detailed account of the molecular and biologic processes involved in HDACI-mediated TCP. Moreover, our preclinical studies provide evidence that dose-limiting TCP induced by HDACIs may be circumvented using a TPO mimetic.
Mice Haploinsufficient for Ets1 and Fli1 Display Middle Ear Abnormalities and Model Aspects of Jacobsen Syndrome
Publisher: Elsevier BV
Date: 07-2015
DOI: 10.1016/J.AJPATH.2015.03.026
Abstract: E26 transformation-specific 1 (ETS1) and friend leukemia integration 1 (FLI1) are members of the ETS family of transcription factors, of which there are 28 in humans. Both genes are hemizygous in Jacobsen syndrome, an 11q contiguous gene deletion disorder involving thrombocytopenia, facial dysmorphism, growth and mental retardation, malformation of the heart and other organs, and hearing impairment associated with recurrent ear infections. To determine whether any of these defects are because of hemizygosity for ETS1 and FLI1, we characterized the phenotype of mice heterozygous for mutant alleles of Ets1 and Fli1. Fli1(+/-) mice displayed mild thrombocytopenia, as did Ets1(+/-)Fli1(+/-) animals. Fli1(+/-) and Ets1(+/-)Fli1(+/-) mice also displayed craniofacial abnormalities, including a small middle ear cavity, short nasal bone, and malformed interface between the nasal bone process and cartilaginous nasal septum. They exhibited hearing impairment, otitis media, fusions of ossicles to the middle ear wall, and deformed stapes. Hearing impairment was more penetrant and stapes malformations were more severe in Ets1(+/-)Fli1(+/-) mice than in Fli1(+/-) mice, indicating partial functional redundancy of these transcription factors during auditory development. Our findings indicate that the short nose, otitis media, and hearing impairment in Jacobsen syndrome are likely because of hemizygosity for ETS1 and FLI1.
Proapoptotic Bak and Bax guard against fatal systemic and organ-specific autoimmune disease
Publisher: Proceedings of the National Academy of Sciences
Date: 24-01-2013
Abstract: Dysregulation of the “intrinsic” apoptotic pathway is associated with the development of cancer and autoimmune disease. Bak and Bax are two proapoptotic members of the Bcl-2 protein family with overlapping, essential roles in the intrinsic apoptotic pathway. Their activity is critical for the control of cell survival during lymphocyte development and homeostasis, best demonstrated by defects in thymic T-cell differentiation and peripheral lymphoid homeostasis caused by their combined loss. Because most bak −/− bax −/− mice die perinatally, the roles of Bax and Bak in immunological tolerance and prevention of autoimmune disease remain unclear. We show that mice reconstituted with a Bak/Bax doubly deficient hematopoietic compartment develop a fatal systemic lupus erythematosus-like autoimmune disease characterized by hypergammaglobulinemia, autoantibodies, lymphadenopathy, glomerulonephritis, and vasculitis. Importantly, these mice also develop a multiorgan autoimmune disease with autoantibodies against most solid glandular structures and evidence of glandular atrophy and necrotizing vasculitis. Interestingly, similar albeit less severe pathology was observed in mice containing a hematopoietic compartment deficient for only Bak, a phenotype reminiscent of the disease seen in patients with point mutations in BAK . These studies demonstrate a critical role for Bak and an ancillary role for Bax in safeguarding immunological tolerance and prevention of autoimmune disease. This suggests that direct activators of the intrinsic apoptotic pathway, such as BH3 mimetics, may be useful for treatment of erse autoimmune diseases.
ETO2-GLIS2 Hijacks Transcriptional Complexes to Drive Cellular Identity and Self-Renewal in Pediatric Acute Megakaryoblastic Leukemia
Publisher: Elsevier BV
Date: 03-2017
DOI: 10.1016/J.CCELL.2017.02.006
Abstract: Chimeric transcription factors are a hallmark of human leukemia, but the molecular mechanisms by which they block differentiation and promote aberrant self-renewal remain unclear. Here, we demonstrate that the ETO2-GLIS2 fusion oncoprotein, which is found in aggressive acute megakaryoblastic leukemia, confers megakaryocytic identity via the GLIS2 moiety while both ETO2 and GLIS2 domains are required to drive increased self-renewal properties. ETO2-GLIS2 directly binds DNA to control transcription of associated genes by upregulation of expression and interaction with the ETS-related ERG protein at enhancer elements. Importantly, specific interference with ETO2-GLIS2 oligomerization reverses the transcriptional activation at enhancers and promotes megakaryocytic differentiation, providing a relevant interface to target in this poor-prognosis pediatric leukemia.
A novel role for the EMT regulator, snai1, in hematopoiesis and leukemia
Publisher: Elsevier BV
Date: 09-2015
Dual requirement for the ETS transcription factors Fli-1 and Erg in hematopoietic stem cells and the megakaryocyte lineage
Publisher: Proceedings of the National Academy of Sciences
Date: 18-08-2009
Abstract: Fli-1 and Erg are closely related members of the Ets family of transcription factors. Both genes are translocated in human cancers, including Ewing's sarcoma, leukemia, and in the case of Erg , more than half of all prostate cancers. Although evidence from mice and humans suggests that Fli-1 is required for megakaryopoiesis, and that Erg is required for normal adult hematopoietic stem cell (HSC) regulation, their precise physiological roles remain to be defined. To elucidate the relationship between Fli-1 and Erg in hematopoiesis, we conducted an analysis of mice carrying mutations in both genes. Our results demonstrate that there is a profound genetic interaction between Fli-1 and Erg . Double heterozygotes displayed phenotypes more dramatic than single heterozygotes: severe thrombocytopenia, with a significant deficit in megakaryocyte numbers and evidence of megakaryocyte dysmorphogenesis, and loss of HSCs accompanied by a reduction in the number of committed hematopoietic progenitor cells. These results illustrate an indispensable requirement for both Fli-1 and Erg in normal HSC and megakaryocyte homeostasis, and suggest these transcription factors may coregulate common target genes.
The Regulation of Platelet Life Span
Publisher: Elsevier
Date: 2013
Agm1/Pgm3-Mediated Sugar Nucleotide Synthesis Is Essential for Hematopoiesis and Development
Publisher: Informa UK Limited
Date: 08-2007
DOI: 10.1128/MCB.00802-07
Two distinct pathways regulate platelet phosphatidylserine exposure and procoagulant function
Publisher: American Society of Hematology
Date: 16-07-2009
DOI: 10.1182/BLOOD-2009-01-200345
Abstract: Procoagulant platelets exhibit hallmark features of apoptotic cells, including membrane blebbing, microvesiculation, and phosphatidylserine (PS) exposure. Although platelets possess many well-known apoptotic regulators, their role in regulating the procoagulant function of platelets is unclear. To clarify this, we investigated the consequence of removing the essential mediators of apoptosis, Bak and Bax, or directly inducing apoptosis with the BH3 mimetic compound ABT-737. Treatment of platelets with ABT-737 triggered PS exposure and a marked increase in thrombin generation in vitro. This increase in procoagulant function was Bak/Bax- and caspase-dependent, but it was unaffected by inhibitors of platelet activation or by chelating extracellular calcium. In contrast, agonist-induced platelet procoagulant function was unchanged in Bak−/−Bax−/− or caspase inhibitor–treated platelets, but it was completely eliminated by extracellular calcium chelators or inhibitors of platelet activation. These studies show the existence of 2 distinct pathways regulating the procoagulant function of platelets.
Mutations in tropomyosin 4 underlie a rare form of human macrothrombocytopenia
Publisher: American Society for Clinical Investigation
Date: 30-01-2017
DOI: 10.1172/JCI86154
Erratum: Two ENU-induced alleles of atp2b2 cause deafness in mice
Publisher: Public Library of Science (PLoS)
Date: 09-07-2013
DOI: 10.1371/ANNOTATION/F605BB2C-37B6-4FA7-A213-324DF679C464
Diagnosis and treatment of
Publisher: Informa UK Limited
Date: 11-2018
Physiological restraint of Bak by Bcl-xL is essential for cell survival
Publisher: Cold Spring Harbor Laboratory
Date: 15-05-2016
Abstract: Due to the myriad interactions between prosurvival and proapoptotic members of the Bcl-2 family of proteins, establishing the mechanisms that regulate the intrinsic apoptotic pathway has proven challenging. Mechanistic insights have primarily been gleaned from in vitro studies because genetic approaches in mammals that produce unambiguous data are difficult to design. Here we describe a mutation in mouse and human Bak that specifically disrupts its interaction with the prosurvival protein Bcl-x L . Substitution of Glu75 in mBak (hBAK Q77) for leucine does not affect the three-dimensional structure of Bak or killing activity but reduces its affinity for Bcl-x L via loss of a single hydrogen bond. Using this mutant, we investigated the requirement for physical restraint of Bak by Bcl-x L in apoptotic regulation. In vitro, Bak Q75L cells were significantly more sensitive to various apoptotic stimuli. In vivo, loss of Bcl-x L binding to Bak led to significant defects in T-cell and blood platelet survival. Thus, we provide the first definitive in vivo evidence that prosurvival proteins maintain cellular viability by interacting with and inhibiting Bak.
Cloning and characterization of the genes encoding the ankyrin repeat and SOCS box-containing proteins Asb-1, Asb-2, Asb-3 and Asb-4
Publisher: Elsevier BV
Date: 11-2000
DOI: 10.1016/S0378-1119(00)00402-9
Abstract: Members of the suppressor of cytokine signalling (SOCS) family of proteins have been shown to inhibit cytokine signalling via direct interactions with JAK kinases or activated cytokine receptors. In addition to their novel amino-terminal regions and SH2 domains that mediate these interactions, the SOCS proteins also contain carboxy-terminal regions of homology called the SOCS box. The SOCS box serves to couple SOCS proteins and their binding partners with the elongin B and C complex, possibly targeting them for degradation. Several other families of proteins also contain SOCS boxes but differ from the SOCS proteins in the type of domain or motif they contain upstream of the SOCS box. We report here the cloning, characterization, mapping and expression analysis of four members of the ankyrin repeat and SOCS box-containing (Asb) protein family.
Intrinsic apoptosis circumvents the functional decline of circulating platelets but does not cause the storage lesion
Publisher: American Society of Hematology
Date: 12-07-2018
DOI: 10.1182/BLOOD-2017-11-816355
Abstract: BAK/BAX depletion in murine platelets reveals that intrinsic apoptosis is not required for the development of the platelet storage lesion. Restriction of platelet life span by intrinsic apoptosis is pivotal to maintain a functional, hemostatically reactive platelet population.
Hematopoietic overexpression of the transcription factor Erg induces lymphoid and erythro-megakaryocytic leukemia.
Publisher: Proceedings of the National Academy of Sciences
Date: 30-08-2012
Abstract: The transcription factor encoded by the E-twenty-six (ETS)-related gene, ERG , is an essential regulator of hematopoietic stem cell function and a potent human oncoprotein. Enforced expression of ERG in murine hematopoietic cells leads to the development of a well-characterized lymphoid leukemia and a less well-defined non lymphoid disease. To clarify the latter, we generated murine bone marrow chimeras with enforced Erg expression in engrafted hematopoietic progenitor cells. As expected, these mice developed lymphoid leukemia. However, the previously reported non lymphoid disease that developed was shown to be a uniform, transplantable leukemia with both erythroid and megakaryocytic characteristics. In vivo, this disease had the overall appearance of an erythroleukemia, with an accumulation of immature erythroblasts that infiltrated the bone marrow, spleen, liver, and lung. However, when stimulated in vitro, leukemic cell clones exhibited both erythroid and megakaryocytic differentiation, suggesting that transformation occurred in a bipotential progenitor. Thus, in mice, Erg overexpression induces the development of not only lymphoid leukemia but also erythro-megakaryocytic leukemia.
The role of the ETS factor erg in zebrafish vasculogenesis
Publisher: Elsevier BV
Date: 03-2009
Mcl-1 and Bcl-xL coordinately regulate megakaryocyte survival
Publisher: American Society of Hematology
Date: 14-06-2012
DOI: 10.1182/BLOOD-2011-12-398834
Abstract: Mature megakaryocytes depend on the function of Bcl-xL, a member of the Bcl-2 family of prosurvival proteins, to proceed safely through the process of platelet shedding. Despite this, loss of Bcl-xL does not prevent the growth and maturation of megakaryocytes, suggesting redundancy with other prosurvival proteins. We therefore generated mice with a megakaryocyte-specific deletion of Mcl-1, which is known to be expressed in megakaryocytes. Megakaryopoiesis, platelet production, and platelet lifespan were unperturbed in Mcl-1Pf4Δ/Pf4Δ animals. However, treatment with ABT-737, a BH3 mimetic compound that inhibits the prosurvival proteins Bcl-2, Bcl-xL, and Bcl-w resulted in the complete ablation of megakaryocytes and platelets. Genetic deletion of both Mcl-1 and Bcl-xL in megakaryocytes resulted in preweaning lethality. Megakaryopoiesis in Bcl-xPf4Δ/Pf4ΔMcl-1Pf4Δ/Pf4Δ embryos was severely compromised, and these animals exhibited ectopic bleeding. Our studies indicate that the combination of Bcl-xL and Mcl-1 is essential for the viability of the megakaryocyte lineage.
Data from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.C.6549562.V1
Abstract: Abstract Pharmacologic inhibition of epigenetic enzymes can have therapeutic benefit against hematologic malignancies. In addition to affecting tumor cell growth and proliferation, these epigenetic agents may induce antitumor immunity. Here, we discovered a novel immunoregulatory mechanism through inhibition of histone deacetylases (HDAC). In models of acute myeloid leukemia (AML), leukemia cell differentiation and therapeutic benefit mediated by the HDAC inhibitor (HDACi) panobinostat required activation of the type I interferon (IFN) pathway. Plasmacytoid dendritic cells (pDC) produced type I IFN after panobinostat treatment, through transcriptional activation of IFN genes concomitant with increased H3K27 acetylation at these loci. Depletion of pDCs abrogated panobinostat-mediated induction of type I IFN signaling in leukemia cells and impaired therapeutic efficacy, whereas combined treatment with panobinostat and IFNα improved outcomes in preclinical models. These discoveries offer a new therapeutic approach for AML and demonstrate that epigenetic rewiring of pDCs enhances antitumor immunity, opening the possibility of exploiting this approach for immunotherapies. Significance: We demonstrate that HDACis induce terminal differentiation of AML through epigenetic remodeling of pDCs, resulting in production of type I IFN that is important for the therapeutic effects of HDACis. The study demonstrates the important functional interplay between the immune system and leukemias in response to HDAC inhibition. i This article is highlighted in the In This Issue feature, p. 1397 /i /
Correction: An essential role for α4A-tubulin in platelet biogenesis
Publisher: Life Science Alliance, LLC
Date: 21-06-2021
Apoptotic Caspases: Multiple or Mistaken Identities?
Publisher: Elsevier BV
Date: 06-2018
DOI: 10.1016/J.TCB.2018.02.003
Abstract: The mitochondrial caspase cascade was originally thought to be required for apoptotic death driven by Bak/Bax-mediated intrinsic apoptosis. It has also been ascribed several 'non-apoptotic' functions, including differentiation, proliferation, and cellular reprogramming. Recent work has demonstrated that, during apoptosis, the caspase cascade suppresses damage-associated molecular pattern (DAMP)-initiated production of cytokines such as type I interferon by the dying cell. The caspase cascade is not required for death to occur instead, it shapes the immunogenic properties of the apoptotic cell. This raises questions about the role of apoptotic caspases in regulating DAMP signaling more generally, puts a new perspective on their non-apoptotic functions, and suggests that pharmacological caspase inhibitors might find new applications as antiviral or anticancer agents.
Mutation discovery in mice by whole exome sequencing
Publisher: Springer Science and Business Media LLC
Date: 2011
Effect of thrombopoietin receptor agonists on the apoptotic profile of platelets in patients with chronic immune thrombocytopenia
Publisher: Wiley
Date: 02-09-2014
DOI: 10.1002/AJH.23832
Abstract: Platelet survival depends upon mediators of apoptosis e.g., Bcl-xL, Bax, and Bak, which are regulated by thrombopoietin (TPO)-mediated AKT signaling. Thrombopoietin receptor (TPO-R) signaling might decrease platelet and/or megakaryocyte apoptosis and increase the platelet count. This study therefore explored anti-apoptotic effects of TPO-R-agonists in vivo on platelets of patients with immune thrombocytopenia. Patients received eltrombopag or romiplostim for two weeks. Total, immature, and large platelet counts were assessed as were Bcl-xL inhibitor assay Bcl-xL Western blot and flow cytometric (FACS) analysis of the AKT-signaling pathway. Eight/ten patients had platelet responses to eltrombopag and all three to romiplostim. Platelet sensitivity to apoptosis by Bcl-xL inhibition was greater in pretreatment patients than controls. This sensitivity normalized after one week of therapy, but surprisingly returned to pretreatment levels at week two. FACS analysis revealed increased AKT-pathway signaling after one week, followed by a decrease at week two. Platelet counts correlated with the Bcl-xL /Bak ratio. Platelet survival may be enhanced by TPO-R-agonists as a transient decrease in platelet sensitivity to apoptosis was accompanied by transient activation of AKT. However, this mechanism has only a short-lived effect. Megakaryocytes and platelets already present at the start of TPO-R-agonist treatment appear to respond differently than those generated de novo.
The Mitochondrial Apoptotic Effectors BAX/BAK Activate Caspase-3 and -7 to Trigger NLRP3 Inflammasome and Caspase-8 Driven IL-1β Activation
Publisher: Elsevier BV
Date: 11-2018
DOI: 10.1016/J.CELREP.2018.10.103
Abstract: Intrinsic apoptosis resulting from BAX/BAK-mediated mitochondrial membrane damage is regarded as immunologically silent. We show here that in macrophages, BAX/BAK activation results in inhibitor of apoptosis (IAP) protein degradation to promote caspase-8-mediated activation of IL-1β. Furthermore, BAX/BAK signaling induces a parallel pathway to NLRP3 inflammasome-mediated caspase-1-dependent IL-1β maturation that requires potassium efflux. Remarkably, following BAX/BAK activation, the apoptotic executioner caspases, caspase-3 and -7, act upstream of both caspase-8 and NLRP3-induced IL-1β maturation and secretion. Conversely, the pyroptotic cell death effectors gasdermin D and gasdermin E are not essential for BAX/BAK-induced IL-1β release. These findings highlight that innate immune cells undergoing BAX/BAK-mediated apoptosis have the capacity to generate pro-inflammatory signals and provide an explanation as to why IL-1β activation is often associated with cellular stress, such as during chemotherapy.
TBK1 and IKKε Act Redundantly to Mediate STING-Induced NF-κB Responses in Myeloid Cells
Publisher: Elsevier BV
Date: 04-2020
DOI: 10.1016/J.CELREP.2020.03.056
Abstract: Stimulator of Interferon Genes (STING) is a critical component of host innate immune defense but can contribute to chronic autoimmune or autoinflammatory disease. Once activated, the cyclic guanosine monophosphate (GMP)-adenosine monophosphate (AMP) (cGAMP) synthase (cGAS)-STING pathway induces both type I interferon (IFN) expression and nuclear factor-κB (NF-κB)-mediated cytokine production. Currently, these two signaling arms are thought to be mediated by a single upstream kinase, TANK-binding kinase 1 (TBK1). Here, using genetic and pharmacological approaches, we show that TBK1 alone is dispensable for STING-induced NF-κB responses in human and mouse immune cells, as well as in vivo. We further demonstrate that TBK1 acts redundantly with IκB kinase ε (IKKε) to drive NF-κB upon STING activation. Interestingly, we show that activation of IFN regulatory factor 3 (IRF3) is highly dependent on TBK1 kinase activity, whereas NF-κB is significantly less sensitive to TBK1/IKKε kinase inhibition. Our work redefines signaling events downstream of cGAS-STING. Our findings further suggest that cGAS-STING will need to be targeted directly to effectively ameliorate the inflammation underpinning disorders associated with STING hyperactivity.
Low adhesion receptor levels on circulating platelets in patients with lymphoproliferative diseases before receiving Navitoclax (ABT-263)
Publisher: American Society of Hematology
Date: 21-02-2013
The SOCS box: a tale of destruction and degradation
Publisher: Elsevier BV
Date: 05-2002
DOI: 10.1016/S0968-0004(02)02085-6
Abstract: Although initially identified in the suppressor of cytokine signaling (SOCS) family of proteins, the C-terminal SOCS box has now been identified in more than 40 proteins in nine different families. Growing evidence suggests that the SOCS box, similar to the F-box, acts as a bridge between specific substrate-binding domains and the more generic proteins that comprise a large family of E3 ubiquitin protein ligases. In this way, SOCS proteins regulate protein turnover by targeting proteins for polyubiquitination and, therefore, for proteasome-mediated degradation.
Thrombocytopenia and erythrocytosis in mice with a mutation in the gene encoding the hemoglobin β minor chain.
Publisher: Proceedings of the National Academy of Sciences
Date: 27-12-2011
Abstract: Diverse mutations in the genes encoding hemoglobin (Hb) have been characterized in human disease. We describe here a mutation in the mouse Hbb-b2 gene, denoted Plt12 , that precisely mimics the human hemoglobin Hotel Dieu variant. The mutation results in increased affinity of Hb for oxygen and Plt12 mutant mice exhibited reduced partial pressure of O 2 in the blood, accompanied by erythrocytosis characterized by elevated erythropoietin levels and splenomegaly with excess erythropoiesis. Most homozygous Hbb-b2 Plt12/Plt12 mice succumbed to early lethality associated with emphysema, cardiac abnormalities, and liver degeneration. Survivors displayed a marked thrombocytopenia without significant deficiencies in the numbers of megakaryocytes or megakaryocyte progenitor cells. The lifespan of platelets in the circulation of Hbb-b2 Plt12/Plt12 mice was normal, and splenectomy did not correct the thrombocytopenia, suggesting that increased sequestration was unlikely to be a major contributor. These data, together with the observation that megakaryocytes in Hbb-b2 Plt12/Plt12 mice appeared smaller and deficient in cytoplasm, support a model in which hypoxia causes thrombocytopenia as a consequence of an inability of megakaryocytes, once formed, to properly mature and produce sufficient platelets. The Plt12 mouse is a model of high O 2 -affinity hemoglobinopathy and provides insights into hematopoiesis under conditions of chronic hypoxia.
Platelet production proceeds independently of the intrinsic and extrinsic apoptosis pathways
Publisher: Springer Science and Business Media LLC
Date: 17-03-2014
DOI: 10.1038/NCOMMS4455
Abstract: BH3 mimetic drugs that target BCL-2 family pro-survival proteins to induce tumour cell apoptosis represent a new era in cancer therapy. Clinical trials of navitoclax (ABT-263, which targets BCL-2, BCL-XL and BCL-W) have shown great promise, but encountered dose-limiting thrombocytopenia. Recent work has demonstrated that this is due to the inhibition of BCL-XL, which is essential for platelet survival. These findings raise new questions about the established model of platelet shedding by megakaryocytes, which is thought to be an apoptotic process. Here we generate mice with megakaryocyte-specific deletions of the essential mediators of extrinsic (Caspase-8) and intrinsic (BAK/BAX) apoptosis. We show that megakaryocytes possess a Fas ligand-inducible extrinsic apoptosis pathway. However, Fas activation does not stimulate platelet production, rather, it triggers Caspase-8-mediated killing. Combined loss of Caspase-8/BAK/BAX does not impair thrombopoiesis, but can protect megakaryocytes from death in mice infected with lymphocytic choriomeningitis virus. Thus, apoptosis is dispensable for platelet biogenesis.
Bacteria differentially induce degradation of Bcl-xL, a survival protein, by human platelets
Publisher: American Society of Hematology
Date: 13-12-2012
DOI: 10.1182/BLOOD-2012-04-420661
Abstract: Bacteria can enter the bloodstream in response to infectious insults. Bacteremia elicits several immune and clinical complications, including thrombocytopenia. A primary cause of thrombocytopenia is shortened survival of platelets. We demonstrate that pathogenic bacteria induce apoptotic events in platelets that include calpain-mediated degradation of Bcl-xL, an essential regulator of platelet survival. Specifically, bloodstream bacterial isolates from patients with sepsis induce lateral condensation of actin, impair mitochondrial membrane potential, and degrade Bcl-xL protein in platelets. Bcl-xL protein degradation is enhanced when platelets are exposed to pathogenic Escherichia coli that produce the pore-forming toxin α-hemolysin, a response that is markedly attenuated when the gene is deleted from E coli. We also found that nonpathogenic E coli gain degrading activity when they are forced to express α-hemolysin. Like α-hemolysin, purified α-toxin readily degrades Bcl-xL protein in platelets, as do clinical Staphylococcus aureus isolates that produce α-toxin. Inhibition of calpain activity, but not the proteasome, rescues Bcl-xL protein degradation in platelets coincubated with pathogenic E coli including α-hemolysin producing strains. This is the first evidence that pathogenic bacteria can trigger activation of the platelet intrinsic apoptosis program and our results suggest a new mechanism by which bacterial pathogens might cause thrombocytopenia in patients with bloodstream infections.
Description of a novel mutation leading to MYH9-related disease
Publisher: Elsevier BV
Date: 2008
Caspase-9 mediates the apoptotic death of megakaryocytes and platelets, but is dispensable for their generation and function
Publisher: American Society of Hematology
Date: 03-05-2012
DOI: 10.1182/BLOOD-2011-11-394858
Abstract: Apoptotic caspases, including caspase-9, are thought to facilitate platelet shedding by megakaryocytes. They are known to be activated during platelet apoptosis, and have also been implicated in platelet hemostatic responses. However, the precise requirement for, and the regulation of, apoptotic caspases have never been defined in either megakaryocytes or platelets. To establish the role of caspases in platelet production and function, we generated mice lacking caspase-9 in their hematopoietic system. We demonstrate that both megakaryocytes and platelets possess a functional apoptotic caspase cascade downstream of Bcl-2 family-mediated mitochondrial damage. Caspase-9 is the initiator caspase, and its loss blocks effector caspase activation. Surprisingly, steady-state thrombopoiesis is unperturbed in the absence of caspase-9, indicating that the apoptotic caspase cascade is not required for platelet production. In platelets, loss of caspase-9 confers resistance to the BH3 mimetic ABT-737, blocking phosphatidylserine (PS) exposure and delaying ABT-737–induced thrombocytopenia in vivo. Despite this, steady-state platelet lifespan is normal. Casp9−/− platelets are fully capable of physiologic hemostatic responses and functional regulation of adhesive integrins in response to agonist. These studies demonstrate that the apoptotic caspase cascade is required for the efficient death of megakaryocytes and platelets, but is dispensable for their generation and function.
Stressed mitochondria sound the alarm
Publisher: Wiley
Date: 10-03-2015
DOI: 10.1038/ICB.2015.31
Transgenic, inducible RNAi in megakaryocytes and platelets in mice
Publisher: Elsevier BV
Date: 12-2010
Two ENU-Induced Alleles of Atp2b2 Cause Deafness in Mice
Publisher: Public Library of Science (PLoS)
Date: 24-06-2013
Cell Death in the Hematopoietic System
Publisher: Humana Press
Date: 2009
Mitochondrial dysfunction caused by outer membrane vesicles from Gram-negative bacteria activates intrinsic apoptosis and inflammation
Publisher: Springer Science and Business Media LLC
Date: 17-08-2020
Individual and overlapping roles of BH3-only proteins Bim and Bad in apoptosis of lymphocytes and platelets and in suppression of thymic lymphoma development
Publisher: Springer Science and Business Media LLC
Date: 30-04-2010
DOI: 10.1038/CDD.2010.43
Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541185.V1
Abstract: Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Platelet senescence is regulated by an internal timer, not damage inflicted by hits
Publisher: American Society of Hematology
Date: 09-09-2010
DOI: 10.1182/BLOOD-2009-12-259663
Abstract: The mechanisms responsible for the brief life span of blood platelets have been a subject of speculation since the 1950s. The most popular hypothesis to date has been the “multiple-hit” model, whereby damage inflicted by external “hits” triggers recognition and clearance by the reticuloendothelial system. Recently, it was demonstrated that platelets contain an apoptotic pathway that mediates their survival in vivo. Using a novel labeling technique to measure population and cohort survival in mice carrying mutations in this pathway, combined with mathematical modeling, we have studied the internal and external control of platelet fate. Our results cast doubt on the veracity of the multiple-hit model. An alternative model, under which platelets are born with an internal “timer,” provides a more parsimonious interpretation of the data. Thus, at steady state, platelet senescence is probably the product of internal processes rather than external hits.
The transcription factor Erg is essential for definitive hematopoiesis and the function of adult hematopoietic stem cells
Publisher: Springer Science and Business Media LLC
Date: 25-05-2008
DOI: 10.1038/NI.1617
Abstract: Ets-related gene (ERG), which encodes a member of the Ets family of transcription factors, is a potent oncogene. Chromosomal rearrangements involving ERG are found in acute myeloid leukemia, acute lymphoblastic leukemia, Ewing's sarcoma and more than half of all prostate cancers however, the normal physiological function of Erg is unknown. We did a sensitized genetic screen of the mouse for regulators of hematopoietic stem cell function and report here a germline mutation of Erg. We show that Erg is required for definitive hematopoiesis, adult hematopoietic stem cell function and the maintenance of normal peripheral blood platelet numbers.
Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541179.V1
Abstract: Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541167
Abstract: Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Developmental Stage–Specific Manifestations of Absent TPO/c-MPL Signalling in Newborn Mice
Publisher: Georg Thieme Verlag KG
Date: 2017
DOI: 10.1160/TH17-06-0433
Abstract: Congenital amegakaryocytic thrombocytopaenia (CAMT) is a disorder caused by c-MPL mutations that impair thrombopoietin (TPO) signalling, resulting in a near absence of megakaryocytes (MKs). While this phenotype is consistent in adults, neonates with CAMT can present with severe thrombocytopaenia despite normal MK numbers. To investigate this, we characterized MKs and platelets in newborn c-MPL –/– mice. Liver MKs in c-MPL –/– neonates were reduced in number and size compared with wild-type (WT) age-matched MKs, and exhibited ultrastructural abnormalities not found in adult c-MPL –/– MKs. Platelet counts were lower in c-MPL –/– compared with WT mice at birth and did not increase over the first 2 weeks of life. In vivo biotinylation revealed a significant reduction in the platelet half-life of c-MPL –/– newborn mice (P2) compared with age-matched WT pups, which was not associated with ultrastructural abnormalities. Genetic deletion of the pro-apoptotic Bak did not rescue the severely reduced platelet half-life of c-MPL –/– newborn mice, suggesting that it was due to factors other than platelets entering apoptosis early. Indeed, adult GFP+ (green fluorescent protein transgenic) platelets transfused into thrombocytopenic c-MPL –/– P2 pups also had a shortened lifespan, indicating the importance of cell-extrinsic factors. In addition, neonatal platelets from WT and c-MPL –/– mice exhibited reduced P-selectin surface expression following stimulation compared with adult platelets of either genotype, and platelets from c-MPL –/– neonates exhibited reduced glycoprotein IIb/IIIa (GPIIb/IIIa) activation in response to thrombin compared with age-matched WT platelets. Taken together, our findings indicate that c-MPL deficiency is associated with abnormal maturation of neonatal MKs and developmental stage-specific defects in platelet function.
A new mouse model of Canavan leukodystrophy displays hearing impairment due to central nervous system dysmyelination
Publisher: The Company of Biologists
Date: 2014
DOI: 10.1242/DMM.014605
Abstract: Canavan disease is a leukodystrophy caused by mutations in the ASPA gene. This gene encodes the enzyme that converts N-acetylaspartate into acetate and aspartic acid. In Canavan disease spongiform encephalopathy of the brain causes progressive mental retardation, motor deficit and death. We have isolated a mouse with a novel ethylnitrosourea-induced mutation in Aspa. This mutant, named deaf14, carries a c.516T& A mutation that is predicted to cause a p.Y172X protein truncation. No full-length ASPA protein is produced in deaf14 brain and there is extensive spongy degeneration. Interestingly, we found that deaf14 mice have an attenuated startle in response to loud noise. The first auditory brainstem response peak has normal latency and litude but peaks II, III, IV and V have increased latency and decreased litude in deaf14 mice. Our work reveals a hitherto unappreciated pathology in a mouse model of Canavan disease, implying that auditory brainstem response testing could be used in diagnosis and to monitor the progression of this disease.
Cell death following the loss of ADAR1 mediated A-to-I RNA editing is not effected by the intrinsic apoptosis pathway
Publisher: Springer Science and Business Media LLC
Date: 04-12-2019
DOI: 10.1038/S41419-019-2160-6
Abstract: Modifications of RNA, collectively termed as the epitranscriptome, are widespread, evolutionarily conserved and contribute to gene regulation and protein ersity in healthy and disease states. There are RNA modifications described, greatly exceeding the number of modifications to DNA. Of these, adenosine-to-inosine (A-to-I) RNA editing is one of the most common. There are tens of thousands of A-to-I editing sites in mouse, and millions in humans. Upon translation or sequencing an inosine base is decoded as guanosine, leading to A-to-G mismatches between the RNA and DNA. Inosine has different base pairing properties to adenosine and as a result editing not only alters the RNA code but can also change the RNA structure. In mammals A-to-I editing is performed by ADAR1 and ADAR2. A feature of murine loss of function ADAR1 alleles is cell death and a failure to survive embryogenesis. Adar1 −/− and editing deficient ( Adar1 E861A/E861A ) mice die between E11.75–13.5 of failed hematopoiesis. Strikingly this phenotype is rescued by the deletion of the cytosolic dsRNA sensor MDA5 or its downstream adaptor MAVS, a mechanism conserved in human and mouse. Current literature indicates that the loss of ADAR1 leads to cell death via apoptosis, yet this has not been genetically established. We report that blockade of the intrinsic (mitochondrial) apoptosis pathway, through the loss of both BAK and BAX, does not rescue or modify the cellular phenotype of the fetal liver or extend the lifespan of ADAR1 editing deficient embryos. We had anticipated that the loss of BAK and BAX would rescue, or at least significantly extend, the gestational viability of Adar1 E861A/E861A embryos. However, the triple mutant Adar1 E861A/E861A Bak −/− Bax −/− embryos that were recovered at E13.5 were indistinguishable from the Adar1 E861A/E861A embryos with BAK and BAX. The results indicate that cell death processes not requiring the intrinsic apoptosis pathway are triggered by MDA5 following the loss of ADAR1.
Correction for Zhang et al., The conserved SOCS box motif in suppressors of cytokine signaling binds to elongins B and C and may couple bound proteins to proteasomal degradation.
Publisher: Proceedings of the National Academy of Sciences
Date: 08-05-2015
Conserved piRNA Expression from a Distinct Set of piRNA Cluster Loci in Eutherian Mammals
Publisher: Public Library of Science (PLoS)
Date: 20-11-2015
Missense mutations in the MLKL ‘brace’ region lead to lethal neonatal inflammation in mice and are present in high frequency in humans
Publisher: Cold Spring Harbor Laboratory
Date: 15-05-2019
DOI: 10.1101/628370
Abstract: We have isolated a mouse strain with a single missense mutation in the gene encoding MLKL, the essential effector of necroptotic cell death. The resulting substitution lies within the two-helix ‘brace’ and confers constitutive, RIPK3 independent, killing activity to MLKL. Mice homozygous for Mlkl D139V develop lethal inflammation within days of birth, implicating the salivary glands and pericardium as hotspots for necroptosis and inflammatory infiltration. The normal development of Mlkl D139V homozygotes until birth, and the absence of any overt phenotype in heterozygotes provides important in vivo precedent for the capacity of cells to clear activated MLKL. These observations offer an important insight into the potential disease-modulating roles of three common human MLKL polymorphisms that encode amino acid substitutions within or adjacent to the brace region. Compound heterozygosity of these variants is found at up to 12-fold the expected frequency in patients that suffer from a pediatric autoinflammatory disease, CRMO.
Regulation of platelet lifespan in the presence and absence of thrombopoietin signaling
Publisher: Elsevier BV
Date: 09-2016
DOI: 10.1111/JTH.13397
Abstract: Essentials We examined platelet survival in models of absent or enhanced thrombopoietin (TPO) signaling. Platelet lifespan is normal in transgenic mice with chronically enhanced TPO signaling. Mpl deficiency does not negatively affect platelet lifespan in the absence of thrombocytopenia. We conclude that TPO and its receptor Mpl are dispensable for platelet survival in adult mice. Background It is well established that thrombopoietin (TPO), acting via its receptor Mpl, is the major cytokine regulator of platelet biogenesis. The primary mechanism by which TPO signaling stimulates thrombopoiesis is via stimulation of Mpl-expressing hematopoietic progenitors Mpl on megakaryocytes and platelets acts to control the amount of TPO available. TPO could potentially reduce platelet and/or megakaryocyte apoptosis, and therefore increase the platelet count. However, the effect of TPO receptor signaling on platelet survival is unresolved. Methods and results Here, we investigated platelet survival in mouse models of absent or enhanced TPO signaling. In the absence of thrombocytopenia, Mpl deficiency did not negatively influence platelet lifespan, and nor was platelet survival affected in transgenic mice with chronically increased TPO signaling. Conclusions We conclude that TPO and its receptor Mpl are dispensable for platelet survival in adult mice.
Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541164
Abstract: Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Acute myeloid leukemia maturation lineage influences residual disease and relapse following differentiation therapy
Publisher: Springer Science and Business Media LLC
Date: 11-11-2021
DOI: 10.1038/S41467-021-26849-W
Abstract: Acute myeloid leukemia (AML) is a malignancy of immature progenitor cells. AML differentiation therapies trigger leukemia maturation and can induce remission, but relapse is prevalent and its cellular origin is unclear. Here we describe high resolution analysis of differentiation therapy response and relapse in a mouse AML model. Triggering leukemia differentiation in this model invariably produces two phenotypically distinct mature myeloid lineages in vivo. Leukemia-derived neutrophils dominate the initial wave of leukemia differentiation but clear rapidly and do not contribute to residual disease. In contrast, a therapy-induced population of mature AML-derived eosinophil-like cells persists during remission, often in extramedullary organs. Using genetic approaches we show that restricting therapy-induced leukemia maturation to the short-lived neutrophil lineage markedly reduces relapse rates and can yield cure. These results indicate that relapse can originate from therapy-resistant mature AML cells, and suggest differentiation therapy combined with targeted eradication of mature leukemia-derived lineages may improve disease outcome.
Germline heterozygous mutations in Nxf1 perturb RNA metabolism and trigger thrombocytopenia and lymphopenia in mice
Publisher: American Society of Hematology
Date: 04-2020
DOI: 10.1182/BLOODADVANCES.2019001323
Abstract: In eukaryotic cells, messenger RNA (mRNA) molecules are exported from the nucleus to the cytoplasm, where they are translated. The highly conserved protein nuclear RNA export factor1 (Nxf1) is an important mediator of this process. Although studies in yeast and in human cell lines have shed light on the biochemical mechanisms of Nxf1 function, its contribution to mammalian physiology is less clear. Several groups have identified recurrent NXF1 mutations in chronic lymphocytic leukemia (CLL), placing it alongside several RNA-metabolism factors (including SF3B1, XPO, RPS15) whose dysregulation is thought to contribute to CLL pathogenesis. We report here an allelic series of germline point mutations in murine Nxf1. Mice heterozygous for these loss-of-function Nxf1 mutations exhibit thrombocytopenia and lymphopenia, together with milder hematological defects. This is primarily caused by cell-intrinsic defects in the survival of platelets and peripheral lymphocytes, which are sensitized to intrinsic apoptosis. In contrast, Nxf1 mutations have almost no effect on red blood cell homeostasis. Comparative transcriptome analysis of platelets, lymphocytes, and erythrocytes from Nxf1-mutant mice shows that, in response to impaired Nxf1 function, the cytoplasmic representation of transcripts encoding regulators of RNA metabolism is altered in a unique, lineage-specific way. Thus, blood cell lineages exhibit differential requirements for Nxf1-mediated global mRNA export.
Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541182.V1
Abstract: Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
MCMV-mediated Inhibition of the Pro-apoptotic Bak Protein Is Required for Optimal In Vivo Replication
Publisher: Public Library of Science (PLoS)
Date: 28-02-2013
MyD88 Is a Critical Regulator of Hematopoietic Cell-Mediated Neuroprotection Seen after Stroke
Publisher: Public Library of Science (PLoS)
Date: 04-03-2013
Mutations in the cofilin partner Aip1/Wdr1 cause autoinflammatory disease and macrothrombocytopenia
Publisher: American Society of Hematology
Date: 10-2007
DOI: 10.1182/BLOOD-2006-10-055087
Abstract: A pivotal mediator of actin dynamics is the protein cofilin, which promotes filament severing and depolymerization, facilitating the breakdown of existing filaments, and the enhancement of filament growth from newly created barbed ends. It does so in concert with actin interacting protein 1 (Aip1), which serves to accelerate cofilin's activity. While progress has been made in understanding its biochemical functions, the physiologic processes the cofilin/Aip1 complex regulates, particularly in higher organisms, are yet to be determined. We have generated an allelic series for WD40 repeat protein 1 (Wdr1), the mammalian homolog of Aip1, and report that reductions in Wdr1 function produce a dramatic phenotype gradient. While severe loss of function at the Wdr1 locus causes embryonic lethality, macrothrombocytopenia and autoinflammatory disease develop in mice carrying hypomorphic alleles. Macrothrombocytopenia is the result of megakaryocyte maturation defects, which lead to a failure of normal platelet shedding. Autoinflammatory disease, which is bone marrow–derived yet nonlymphoid in origin, is characterized by a massive infiltration of neutrophils into inflammatory lesions. Cytoskeletal responses are impaired in Wdr1 mutant neutrophils. These studies establish an essential requirement for Wdr1 in megakaryocytes and neutrophils, indicating that cofilin-mediated actin dynamics are critically important to the development and function of both cell types.
Megakaryocytes possess a functional intrinsic apoptosis pathway that must be restrained to survive and produce platelets
Publisher: Rockefeller University Press
Date: 12-09-2011
DOI: 10.1084/JEM.20110750
Abstract: It is believed that megakaryocytes undergo a specialized form of apoptosis to shed platelets. Conversely, a range of pathophysiological insults, including chemotherapy, are thought to cause thrombocytopenia by inducing the apoptotic death of megakaryocytes and their progenitors. To resolve this paradox, we generated mice with hematopoietic- or megakaryocyte-specific deletions of the essential mediators of apoptosis, Bak and Bax. We found that platelet production was unperturbed. In stark contrast, deletion of the prosurvival protein Bcl-xL resulted in megakaryocyte apoptosis and a failure of platelet shedding. This could be rescued by deletion of Bak and Bax. We examined the effect on megakaryocytes of three agents that activate the intrinsic apoptosis pathway in other cell types: etoposide, staurosporine, and the BH3 mimetic ABT-737. All three triggered mitochondrial damage, caspase activation, and cell death. Deletion of Bak and Bax rendered megakaryocytes resistant to etoposide and ABT-737. In vivo, mice with a Bak−/− Bax−/− hematopoietic system were protected against thrombocytopenia induced by the chemotherapeutic agent carboplatin. Thus, megakaryocytes do not activate the intrinsic pathway to generate platelets rather, the opposite is true: they must restrain it to survive and progress safely through proplatelet formation and platelet shedding.
A mouse model of hereditary coproporphyria identified in an ENU mutagenesis screen
Publisher: The Company of Biologists
Date: 2017
DOI: 10.1242/DMM.029116
Abstract: A genome-wide ENU mutagenesis screen in mice was performed to identify novel regulators of erythropoiesis. Here we describe a mouse line, RBC16, which harbours a dominantly inherited mutation in the Cpox gene, responsible for production of the haem biosynthesis enzyme, coproporphyrinogen III oxidase (CPOX). A premature stop codon in place of a tryptophan at amino acid 373 results in reduced mRNA expression and diminished protein levels, yielding a microcytic red cell phenotype in heterozygous mice. Urinary and faecal porphyrins in female RBC16 heterozygotes were significantly elevated compared to that of wildtype littermates, particularly coproporphyrinogen III, while males were biochemically normal. Attempts to induce acute porphyric crises were made using fasting and phenobarbital treatment on females. While fasting had no biochemical effect on RBC16 mice, phenobarbital caused significant elevation of faecal coproporphyrinogen III in heterozygous mice. This is the first known investigation of a mutagenesis mouse model with genetic and biochemical parallels to hereditary coproporphyria.
High ploidy large cytoplasmic megakaryocytes are hematopoietic stem cells regulators and essential for platelet production
Publisher: Springer Science and Business Media LLC
Date: 13-04-2023
DOI: 10.1038/S41467-023-37780-7
Abstract: Megakaryocytes (MK) generate platelets. Recently, we and others, have reported MK also regulate hematopoietic stem cells (HSC). Here we show high ploidy large cytoplasmic megakaryocytes (LCM) are critical negative regulators of HSC and critical for platelet formation. Using a mouse knockout model ( Pf4-Srsf3 Δ/Δ ) with normal MK numbers, but essentially devoid of LCM, we demonstrate a pronounced increase in BM HSC concurrent with endogenous mobilization and extramedullary hematopoiesis. Severe thrombocytopenia is observed in animals with diminished LCM, although there is no change in MK ploidy distribution, uncoupling endoreduplication and platelet production. When HSC isolated from a microenvironment essentially devoid of LCM reconstitute hematopoiesis in lethally irradiated mice, the absence of LCM increases HSC in BM, blood and spleen, and the recapitulation of thrombocytopenia. In contrast, following a competitive transplant using minimal numbers of WT HSC together with HSC from a microenvironment with diminished LCM, sufficient WT HSC-generated LCM regulates a normal HSC pool and prevents thrombocytopenia. Importantly, LCM are conserved in humans.
Expansion of the neonatal platelet mass is achieved via an extension of platelet lifespan
Publisher: American Society of Hematology
Date: 29-05-2014
DOI: 10.1182/BLOOD-2013-06-508200
Abstract: Rapid growth and rising platelet counts result in a significant expansion of platelet mass during neonatal life. The rise in platelet counts is mediated by a prolongation in the neonatal platelet lifespan.
The art and design of genetic screens: mouse
Publisher: Springer Science and Business Media LLC
Date: 07-2005
DOI: 10.1038/NRG1636
Abstract: Humans are mammals, not bacteria or plants, yeast or nematodes, insects or fish. Mice are also mammals, but unlike gorilla and goat, fox and ferret, giraffe and jackal, they are suited perfectly to the laboratory environment and genetic experimentation. In this review, we will summarize the tools, tricks and techniques for executing forward genetic screens in the mouse and argue that this approach is now accessible to most biologists, rather than being the sole domain of large national facilities and specialized genetics laboratories.
Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541176.V1
Abstract: Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541179
Abstract: Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
The suppressors of cytokine signalling (SOCS)
Publisher: Springer Science and Business Media LLC
Date: 10-2001
DOI: 10.1007/PL00000801
The conserved SOCS box motif in suppressors of cytokine signaling binds to elongins B and C and may couple bound proteins to proteasomal degradation.
Publisher: Proceedings of the National Academy of Sciences
Date: 02-03-1999
Abstract: The suppressors of cytokine signaling (SOCS) family of proteins act as intracellular inhibitors of several cytokine signal transduction pathways. Their expression is induced by cytokine activation of the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway and they act as a negative feedback loop by subsequently inhibiting the JAK/STAT pathway either by direct interaction with activated JAKs or with the receptors. These interactions are mediated at least in part by the SH2 domain of SOCS proteins but these proteins also contain a highly conserved C-terminal homology domain termed the SOCS box. Here we show that the SOCS box mediates interactions with elongins B and C, which in turn may couple SOCS proteins and their substrates to the proteasomal protein degradation pathway. Analogous to the family of F-box-containing proteins, it appears that the SOCS proteins may act as adaptor molecules that target activated cell signaling proteins to the protein degradation pathway.
IL-18 Production from the NLRP1 Inflammasome Prevents Obesity and Metabolic Syndrome
Publisher: Elsevier BV
Date: 2016
DOI: 10.1016/J.CMET.2015.09.024
Abstract: Interleukin-18 (IL-18) is activated by Caspase-1 in inflammasome complexes and has anti-obesity effects however, it is not known which inflammasome regulates this process. We found that mice lacking the NLRP1 inflammasome phenocopy mice lacking IL-18, with spontaneous obesity due to intrinsic lipid accumulation. This is exacerbated when the mice are fed a high-fat diet (HFD) or a high-protein diet, but not when mice are fed a HFD with low energy density (high fiber). Furthermore, mice with an activating mutation in NLRP1, and hence increased IL-18, have decreased adiposity and are resistant to diet-induced metabolic dysfunction. Feeding these mice a HFD further increased plasma IL-18 concentrations and strikingly resulted in loss of adipose tissue mass and fatal cachexia, which could be prevented by genetic deletion of IL-18. Thus, NLRP1 is an innate immune sensor that functions in the context of metabolic stress to produce IL-18, preventing obesity and metabolic syndrome.
A Model for Studying the Hemostatic Consumption or Destruction of Platelets
Publisher: Public Library of Science (PLoS)
Date: 07-03-2013
Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541173
Abstract: Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
SOCS4 is dispensable for an efficient recall response to influenza despite being required for primary immunity
Publisher: Wiley
Date: 16-06-2015
DOI: 10.1038/ICB.2015.55
Abstract: Suppressor of cytokine signaling (SOCS) proteins are key regulators of innate and adaptive immunity. Mice lacking functional SOCS4 are hypersusceptible to primary infection with influenza A virus (IAV), displaying dysregulated pro-inflammatory cytokine and chemokine production in the lungs, delayed viral clearance and impaired trafficking of influenza-specific CD8(+) T cells to the site of infection. Therefore, we postulated that SOCS4 is a critical regulator of anti-viral immunity. Unexpectedly, SOCS4 was not required for CD8(+) T-cell memory generation, nor was it required to efficiently recall those cells in response to secondary IAV infection. Wild-type or SOCS4-deficient mice primed and re-challenged with serologically different influenza strains, did not show differences in susceptibility to IAV and cleared the virus from the lungs at the same rate. We have not observed differences in trafficking or numbers of IAV-specific cells, numbers of resident memory T cells or in cytokine profiles in lungs of infected animals. Our data show that despite an impaired primary immune response in Socs4(R108X/R108X) mice, SOCS4 is dispensable for an efficient recall response to influenza virus infection.
Recipient BCL2 inhibition and NK cell ablation form part of a reduced intensity conditioning regime that improves allo-bone marrow transplantation outcomes
Publisher: Springer Science and Business Media LLC
Date: 12-11-2019
Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541170
Abstract: Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Translation inhibitors induce cell death by multiple mechanisms and Mcl-1 reduction is only a minor contributor
Publisher: Springer Science and Business Media LLC
Date: 11-10-2012
Autophagy induced during apoptosis degrades mitochondria and inhibits type I interferon secretion
Publisher: Springer Science and Business Media LLC
Date: 11-12-2017
A small molecule interacts with VDAC2 to block mouse BAK-driven apoptosis
Publisher: Springer Science and Business Media LLC
Date: 07-10-2019
DOI: 10.1038/S41589-019-0365-8
Abstract: Activating the intrinsic apoptosis pathway with small molecules is now a clinically validated approach to cancer therapy. In contrast, blocking apoptosis to prevent the death of healthy cells in disease settings has not been achieved. Caspases have been favored, but they act too late in apoptosis to provide long-term protection. The critical step in committing a cell to death is activation of BAK or BAX, pro-death BCL-2 proteins mediating mitochondrial damage. Apoptosis cannot proceed in their absence. Here we show that WEHI-9625, a novel tricyclic sulfone small molecule, binds to VDAC2 and promotes its ability to inhibit apoptosis driven by mouse BAK. In contrast to caspase inhibitors, WEHI-9625 blocks apoptosis before mitochondrial damage, preserving cellular function and long-term clonogenic potential. Our findings expand on the key role of VDAC2 in regulating apoptosis and demonstrate that blocking apoptosis at an early stage is both advantageous and pharmacologically tractable.
Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541176
Abstract: Supplementary Table from Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML
Genetic modifier screens in mice
Publisher: Wiley
Date: 03-2012
DOI: 10.1002/9780470942390.MO110161
Abstract: ENU mutagenesis is a forward genetics strategy in which random mutagenesis and phenotypic screening is used to identify genes based on the phenotype induced when they are mutated. A modifier screen is a type of screen in which mice with a pre‐existing phenotype are utilized to identify mutations that can enhance or suppress this phenotype. This approach has the potential to uncover missing pathway members, reveal novel genetic interactions, and pinpoint new drug targets. Considerations when planning a suppressor screen include current knowledge, genomic footprint, penetrance, variance, robustness, latency of the starting phenotype, viability, fertility, genetic background and ENU tolerance of starting strain, screening assay, mouse numbers required, and mutation identification strategy. Practical advice on each of these is provided in this review. Curr. Protoc. Mouse Biol . 2:75‐87 © 2012 by John Wiley & Sons, Inc.
Ankyrin repeat and suppressors of cytokine signaling box protein Asb-9 targets creatine kinase B for degradation
Publisher: Elsevier BV
Date: 02-2007
NLRP1a Expression in Srebp-1a-Deficient Mice
Publisher: Elsevier BV
Date: 03-2014
Thrombocytopenia and kidney disease in mice with a mutation in the C1galt1 gene
Publisher: Proceedings of the National Academy of Sciences
Date: 31-10-2006
Abstract: An N -ethyl- N -nitrosourea mutagenesis screen in mice was performed to isolate regulators of circulating platelet number. We report here recessive thrombocytopenia and kidney disease in plt1 mice, which is the result of a severe but partial loss-of-function mutation in the gene encoding glycoprotein- N -acetylgalactosamine-3-β-galactosyltransferase (C1GalT1), an enzyme essential for the synthesis of extended mucin-type O-glycans. Platelet half-life and basic hemostatic parameters were unaffected in plt1 lt1 mice, and the thrombocytopenia and kidney disease were not attenuated on a lymphocyte-deficient rag1 -null background. gpIbα and podocalyxin were found to be major underglycosylated proteins in plt1 lt1 platelets and the kidney, respectively, implying that these are key targets for C1GalT1, appropriate glycosylation of which is essential for platelet production and kidney function. Compromised C1GalT1 activity has been associated with immune-mediated diseases in humans, most notably Tn syndrome and IgA nephropathy. The disease in plt1 lt1 mice suggests that, in addition to immune-mediated effects, intrinsic C1Gal-T1 deficiency in megakaryocytes and the kidney may contribute to pathology.
Apoptotic mitochondria prime anti-tumour immunity
Publisher: Springer Science and Business Media LLC
Date: 07-10-2020
Platelet Life Span and Apoptosis
Publisher: Springer New York
Date: 17-11-2011
DOI: 10.1007/978-1-61779-307-3_5
Abstract: Like many nucleated mammalian cells, the life and death of the anucleate platelet is regulated by Bcl-2 family proteins. Platelets depend on Bcl-x(L) for survival. Bcl-x(L) maintains platelet viability by restraining the killer protein Bak. When Bak is unleashed, it triggers classical intrinsic apoptosis by causing mitochondrial damage. The latter leads to caspase activation and phosphatidylserine (PS) exposure. Platelet apoptosis can be blocked by caspase inhibitors, or by genetic deletion of Bak and its close relative Bax. Perturbations in the platelet apoptosis program lead to changes in platelet life span in vivo. Here, we describe methods to determine platelet life span, enumerate young platelets, and measure hallmarks of platelet apoptosis, such as PS exposure, caspase activation, and mitochondrial dysfunction.
A lineage of diploid platelet-forming cells precedes polyploid megakaryocyte formation in the mouse embryo
Publisher: American Society of Hematology
Date: 23-10-2014
DOI: 10.1182/BLOOD-2014-02-559468
Abstract: The first embryonic platelets are produced by a unique lineage of diploid cells not polyploid MKs. Diploid platelet-forming cells are produced in the early mouse embryo via a progenitor cell–independent pathway.
Termination of STING responses is mediated via ESCRT ‐dependent degradation
Publisher: EMBO
Date: 04-05-2023
Abstract: cGAS‐STING signalling is induced by detection of foreign or mislocalised host double‐stranded (ds)DNA within the cytosol. STING acts as the major signalling hub, where it controls production of type I interferons and inflammatory cytokines. Basally, STING resides on the ER membrane. Following activation STING traffics to the Golgi to initiate downstream signalling and subsequently to endolysosomal compartments for degradation and termination of signalling. While STING is known to be degraded within lysosomes, the mechanisms controlling its delivery remain poorly defined. Here we utilised a proteomics‐based approach to assess phosphorylation changes in primary murine macrophages following STING activation. This identified numerous phosphorylation events in proteins involved in intracellular and vesicular transport. We utilised high‐temporal microscopy to track STING vesicular transport in live macrophages. We subsequently identified that the endosomal complexes required for transport (ESCRT) pathway detects ubiquitinated STING on vesicles, which facilitates the degradation of STING in murine macrophages. Disruption of ESCRT functionality greatly enhanced STING signalling and cytokine production, thus characterising a mechanism controlling effective termination of STING signalling.
A Mouse Model of Harlequin Ichthyosis Delineates a Key Role for Abca12 in Lipid Homeostasis
Publisher: Public Library of Science (PLoS)
Date: 19-09-2008
Neutrophil macroaggregates promote widespread pulmonary thrombosis after gut ischemia
Publisher: American Association for the Advancement of Science (AAAS)
Date: 27-09-2017
DOI: 10.1126/SCITRANSLMED.AAM5861
Abstract: Neutrophil macroaggregates induce a distinct arterial-venous thrombotic response in the lung after gut ischemia.
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Walter And Eliza Hall Institute Of Medical Research
Location: Australia
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Discovery Projects - Grant ID: DP200103637
Start Date: 12-2020
End Date: 06-2025
Amount: $530,000.00
Funder: Australian Research Council
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End Date: 12-2019
Amount: $255,120.00
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View Funded ActivityDiscovery Projects - Grant ID: DP0556154
Start Date: 2005
End Date: 12-2008
Amount: $500,630.00
Funder: Australian Research Council
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