ORCID Profile
0000-0002-7246-3608
Current Organisation
National Institute of Mental Health
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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)
Simulation and Modelling | Medical Biochemistry and Metabolomics | Neurosciences | Cellular Nervous System | Central Nervous System | Regenerative Medicine (incl. Stem Cells and Tissue Engineering) | Medical Biochemistry and Metabolomics not elsewhere classified | Nanobiotechnology | Cell Development, Proliferation and Death
ANZSRC Socio-Economic Objective (SEO)
Cardiovascular System and Diseases | Nervous System and Disorders | Blood Disorders | Expanding Knowledge in the Biological Sciences |
Related Links
Publications
Primate-specific response of astrocytes to stroke limits peripheral macrophage infiltration
Publisher: Cold Spring Harbor Laboratory
Date: 10-05-2020
DOI: 10.1101/2020.05.08.083501
Abstract: Reactive astrocytes play critical roles after brain injuries but their precise function in stroke is not well defined. Here, we utilized single nuclei transcriptomics to characterize astrocytes after ischemic stroke in nonhuman primate (NHP) marmoset monkey primary visual cortex. We identified 19 putative subtypes of astrocytes from injured and uninjured brain hemispheres and observed nearly complete segregation between stroke and control astrocyte clusters. We then screened for genes that might be limiting stroke recovery and discovered that one neurite-outgrowth inhibitory protein, NogoA, previously associated with oligodendrocytes but not astrocytes, was expressed in numerous reactive astrocyte subtypes. NogoA upregulation on reactive astrocytes was confirmed in vivo for NHP and human, but not observed to the same extent in rodent. Further in vivo and in vitro studies determined that NogoA mediated an anti-inflammatory response which limits deeper infiltration of peripheral macrophages from the lesion during the subacute post-stroke period. Specifically, these findings are relevant to the development of NogoA-targeting therapies shortly after ischemic stroke. Our findings have uncovered the complexity and species specificity of astrocyte responses, which need to be considered more when investigating novel therapeutics for brain injury.
Nanodiamonds with silicon vacancy defects for nontoxic photostable fluorescent labeling of neural precursor cells
Publisher: The Optical Society
Date: 11-10-2013
DOI: 10.1364/OL.38.004170
Endogenous neurogenesis following ischaemic brain injury: Insights for therapeutic strategies
Publisher: Elsevier BV
Date: 11-2014
DOI: 10.1016/J.BIOCEL.2014.08.003
Abstract: Ischaemic stroke is among the most common yet most intractable types of central nervous system (CNS) injury in the adult human population. In the acute stages of disease, neurons in the ischaemic lesion rapidly die and other neuronal populations in the ischaemic penumbra are vulnerable to secondary injury. Multiple parallel approaches are being investigated to develop neuroprotective, reparative and regenerative strategies for the treatment of stroke. Accumulating evidence indicates that cerebral ischaemia initiates an endogenous regenerative response within the adult brain that potentiates adult neurogenesis from populations of neural stem and progenitor cells. A major research focus has been to understand the cellular and molecular mechanisms that underlie the potentiation of adult neurogenesis and to appreciate how interventions designed to modulate these processes could enhance neural regeneration in the post-ischaemic brain. In this review, we highlight recent advances over the last 5 years that help unravel the cellular and molecular mechanisms that potentiate endogenous neurogenesis following cerebral ischaemia and are dissecting the functional importance of this regenerative mechanism following brain injury. This article is part of a Directed Issue entitled: Regenerative Medicine: the challenge of translation.
Development of hydrocephalus in mice lacking SOCS7
Publisher: Proceedings of the National Academy of Sciences
Date: 19-10-2004
Abstract: SOCS7 is a member of the suppressor of cytokine signaling (SOCS) family of proteins (SOCS1-SOCS7 and CIS). SOCS proteins are composed of an N-terminal domain of variable length, a central Src homology 2 domain, and a C-terminal SOCS box. Biochemical and genetic studies have revealed that SOCS1, SOCS2, SOCS3, and CIS play an important role in the termination of cytokine and growth factor signaling. However, the biological actions of other SOCS proteins are less well defined. To investigate the physiological role of SOCS7, we have used gene targeting to generate mice that lack expression of the Socs7 gene. Socs7 -/- mice were born in expected numbers, were fertile, and did not exhibit defects in hematopoiesis or circulating glucose or insulin concentrations. However, Socs7 -/- mice were 7-10% smaller than their wild-type littermates, and within 15 weeks of age ≈50% of the Socs7 -/- mice died as a result of hydrocephalus that was characterized by cranial distortion, dilation of the ventricular system, reduced thickness of the cerebral cortex, and disorganization of the subcommissural organ. In situ hybridization studies revealed prominent expression of Socs7 in the brain, suggestive of an important functional role of SOCS7 in this organ.
Role of Cytokines as Mediators and Regulators of Microglial Activity in Inflammatory Demyelination of the CNS
Publisher: Springer Science and Business Media LLC
Date: 30-03-2010
DOI: 10.1007/S12017-010-8112-Z
Abstract: As the resident innate immune cells of the central nervous system (CNS), microglia fulfil a critical role in maintaining tissue homeostasis and in directing and eliciting molecular responses to CNS damage. The human disease Multiple Sclerosis and animal models of inflammatory demyelination are characterized by a complex interplay between degenerative and regenerative processes, many of which are regulated and mediated by microglia. Cellular communication between microglia and other neural and immune cells is controlled to a large extent by the activity of cytokines. Here we review the role of cytokines as mediators and regulators of microglial activity in inflammatory demyelination, highlighting their importance in potentiating cell damage, promoting neuroprotection and enhancing cellular repair in a context-dependent manner.
In vivo whole brain, cellular and molecular imaging in nonhuman primate models of neuropathology
Publisher: Elsevier BV
Date: 07-2016
DOI: 10.1016/J.NEUBIOREV.2016.04.009
Abstract: Rodents have been the principal model to study brain anatomy and function due to their well-mapped brain architecture, rapid reproduction and amenability to genetic modification. However, there are clear limitations, for ex le their simpler neocortex, necessitating the need to adopt a model that is closer to humans in order to understand human cognition and brain conditions. Nonhuman primates (NHPs) are ideally suited as they are our closest relatives in the animal kingdom but in vivo imaging technologies to study brain structure and function in these species can be challenging. With the surge in NHP research in recent years, scientists have begun adapting imaging technologies, such as two-photon microscopy, for these species. Here we review the various NHP models that exist as well as their use in advanced microscopic and mesoscopic studies. We discuss the challenges in the field and investigate the opportunities that lie ahead.
NogoA-expressing astrocytes limit peripheral macrophage infiltration after ischemic brain injury in primates
Publisher: Springer Science and Business Media LLC
Date: 25-11-2021
DOI: 10.1038/S41467-021-27245-0
Abstract: Astrocytes play critical roles after brain injury, but their precise function is poorly defined. Utilizing single-nuclei transcriptomics to characterize astrocytes after ischemic stroke in the visual cortex of the marmoset monkey, we observed nearly complete segregation between stroke and control astrocyte clusters. Screening for the top 30 differentially expressed genes that might limit stroke recovery, we discovered that a majority of astrocytes expressed RTN4A/ NogoA, a neurite-outgrowth inhibitory protein previously only associated with oligodendrocytes. NogoA upregulation on reactive astrocytes post-stroke was significant in both the marmoset and human brain, whereas only a marginal change was observed in mice. We determined that NogoA mediated an anti-inflammatory response which likely contributes to limiting the infiltration of peripheral macrophages into the surviving parenchyma.
The Transcriptional Coactivator Querkopf Controls Adult Neurogenesis
Publisher: Society for Neuroscience
Date: 11-2006
DOI: 10.1523/JNEUROSCI.2247-06.2006
Abstract: The adult mammalian brain maintains populations of neural stem cells within discrete proliferative zones. Understanding of the molecular mechanisms regulating adult neural stem cell function is limited. Here, we show that MYST family histone acetyltransferase Querkopf ( Qkf, Myst4, Morf )-deficient mice have cumulative defects in adult neurogenesis in vivo , resulting in declining numbers of olfactory bulb interneurons, a population of neurons produced in large numbers during adulthood. Qkf- deficient mice have fewer neural stem cells and fewer migrating neuroblasts in the rostral migratory stream. Qkf gene expression is strong in the neurogenic subventricular zone. A population enriched in multipotent cells can be isolated from this region on the basis of Qkf gene expression. Neural stem cells rogenitor cells isolated from Qkf mutant mice exhibited a reduced self-renewal capacity and a reduced ability to produce differentiated neurons. Together, our data show that Qkf is essential for normal adult neurogenesis.
L-selectin and intercellular adhesion molecule 1 mediate lymphocyte migration to the inflamed airway/lung during an allergic inflammatory response in an animal model of asthma
Publisher: Elsevier BV
Date: 04-2001
Abstract: T lymphocytes play a critical role in the development of allergic inflammation in asthma. Early in the allergic response, T lymphocytes migrate from the circulation into the lung to initiate and propagate airway inflammation. The adhesion molecules that mediate lymphocyte entry into inflamed lung have not been defined. This study directly examined the roles of L-selectin and intercellular adhesion molecule 1 (ICAM-1) in lymphocyte migration to the lung during an allergic inflammatory response in an animal model of asthma. Short-term (1 hour) in vivo migration assays and various combinations of adhesion molecule-deficient and wild-type mice were used. Migration of in vivo activated lymphocytes into inflamed lung was significantly greater than entry of resting lymphocytes into noninflamed lung (24.5% +/- 2.7% vs 9.5% +/- 1.3%, P =.001). Migration of activated lymphocytes into inflamed lung was inhibited by 30% in the absence of L-selectin (17.3% +/- 1.3%, P =.04), 47% in the absence of cell surface ICAM-1 (13.0% +/- 2.5%, P =.01), and 47% in the absence of endothelial ICAM-1 (13.0% +/- 2.5%, P =.01). Loss of ICAM-1 on both lymphocytes and lung endothelium inhibited lymphocyte migration by 60% (9.8% +/- 1.8%, P =.002). These findings demonstrate clear roles for both L-selectin and ICAM-1 in lymphocyte migration to the lung during an allergic inflammatory response, with ICAM-1 playing a greater role.
SOCS3 negatively regulates LIF signaling in neural precursor cells.
Publisher: Elsevier BV
Date: 04-2006
DOI: 10.1016/J.MCN.2006.01.005
Abstract: Cytokines that signal through the LIFRbeta/gp130 receptor complex, including LIF and CNTF, promote the self-renewal of embryonic and adult neural precursor cells (NPCs). In non-CNS tissues, the protein suppressor of cytokine signaling-3 (SOCS3) negatively regulates signaling through gp130. Here, we analyze the role of SOCS3 in inhibiting LIF signaling in NPCs in vitro. SOCS3 is rapidly expressed by NPCs in response to LIF stimulation, with this expression largely dependent on recruitment of STAT proteins to the activated gp130 receptor. Proliferating NPC cultures can be generated from SOCS3 knockout (SOCS3KO/KO) embryos and display prolonged STAT3 phosphorylation and induction of the GFAP gene in response to LIF. In comparison with SOCS3 wild-type (SOCS3WT/WT) NPCs, SOCS3KO/KO cultures display enhanced self-renewal capacity. However, the clonal potential of SOCS3WT/WT but not SOCS3KO/KO NPCs is enhanced by exogenous LIF. Thus, SOCS3 acts as a negative regulator of LIF signaling in NPCs.
Pharmacogenetic stimulation of neuronal activity increases myelination in an axon-specific manner
Publisher: Springer Science and Business Media LLC
Date: 22-01-2018
DOI: 10.1038/S41467-017-02719-2
Abstract: Mounting evidence suggests that neuronal activity influences myelination, potentially allowing for experience-driven modulation of neural circuitry. The degree to which neuronal activity is capable of regulating myelination at the in idual axon level is unclear. Here we demonstrate that stimulation of somatosensory axons in the mouse brain increases proliferation and differentiation of oligodendrocyte progenitor cells (OPCs) within the underlying white matter. Stimulated axons display an increased probability of being myelinated compared to neighboring non-stimulated axons, in addition to being ensheathed with thicker myelin. Conversely, attenuating neuronal firing reduces axonal myelination in a selective activity-dependent manner. Our findings reveal that the process of selecting axons for myelination is strongly influenced by the relative activity of in idual axons within a population. These observed cellular changes are consistent with the emerging concept that adaptive myelination is a key mechanism for the fine-tuning of neuronal circuitry in the mammalian CNS.
The early postnatal nonhuman primate neocortex contains self-renewing multipotent neural progenitor cells
Publisher: Public Library of Science (PLoS)
Date: 28-03-2012
Gene network disruptions and neurogenesis defects in the adult Ts1Cje mouse model of Down syndrome.
Publisher: Public Library of Science (PLoS)
Date: 16-07-2010
Over-expression of RCAN1 causes down syndrome-like hippocampal deficits that alter learning and memory
Publisher: Oxford University Press (OUP)
Date: 17-04-2012
DOI: 10.1093/HMG/DDS134
Abstract: People with Down syndrome (DS) exhibit abnormal brain structure. Alterations affecting neurotransmission and signalling pathways that govern brain function are also evident. A large number of genes are simultaneously expressed at abnormal levels in DS therefore, it is a challenge to determine which gene(s) contribute to specific abnormalities, and then identify the key molecular pathways involved. We generated RCAN1-TG mice to study the consequences of RCAN1 over-expression and investigate the contribution of RCAN1 to the brain phenotype of DS. RCAN1-TG mice exhibit structural brain abnormalities in those areas affected in DS. The volume and number of neurons within the hippoc us is reduced and this correlates with a defect in adult neurogenesis. The density of dendritic spines on RCAN1-TG hippoc al pyramidal neurons is also reduced. Deficits in hippoc al-dependent learning and short- and long-term memory are accompanied by a failure to maintain long-term potentiation (LTP) in hippoc al slices. In response to LTP induction, we observed diminished calcium transients and decreased phosphorylation of CaMKII and ERK1/2-proteins that are essential for the maintenance of LTP and formation of memory. Our data strongly suggest that RCAN1 plays an important role in normal brain development and function and its up-regulation likely contributes to the neural deficits associated with DS.
Axonal activity-dependent myelination in development: Insights for myelin repair.
Publisher: Elsevier BV
Date: 10-2016
DOI: 10.1016/J.JCHEMNEU.2016.03.002
Abstract: Recent advances in transgenic tools have allowed us to peek into the earliest stages of vertebrate development to study axon-glial communication in the control of peri-natal myelination. The emerging role of neuronal activity in regulating oligodendrocyte progenitor cell behavior during developmental myelination has opened up an exciting possibility-a role for neuronal activity in the early stages of remyelination. Recent work from our laboratory and others has also shown that contrary to previously established dogma in the field, complete remyelination up to pre-demyelination levels can be achieved in mouse models of MS by oligodendrogenic neural precursor cells that derive from the adult subventricular zone. These cells are electrically active and can be depolarized, suggesting that neuronal activity may have a modulatory role in their development and remyelination potential. In this review, we summarize recent advances in our understanding of the development of axon-glia communication and apply those same concepts to remyelination, with an emphasis on the particular roles of different sources of oligodendrocyte progenitor cells.
p75 Neurotrophin Receptor Expression Defines a Population of BDNF-Responsive Neurogenic Precursor Cells
Publisher: Society for Neuroscience
Date: 09-05-2007
DOI: 10.1523/JNEUROSCI.0654-07.2007
Abstract: Although our understanding of adult neurogenesis has increased dramatically over the last decade, confusion still exists regarding both the identity of the stem cell responsible for neuron production and the mechanisms that regulate its activity. Here we show, using flow cytometry, that a small population of cells (0.3%) within the stem cell niche of the rat subventricular zone (SVZ) expresses the p75 neurotrophin receptor (p75 NTR ) and that these cells are responsible for neuron production in both newborn and adult animals. In the adult, the p75 NTR -positive population contains all of the neurosphere-producing precursor cells, whereas in the newborn many of the precursor cells are p75 NTR negative. However, at both ages, only the neurospheres derived from p75 NTR -positive cells are neurogenic. We also show that neuron production from p75 NTR -positive but not p75 NTR -negative precursors is greatly enhanced after treatment with brain-derived neurotrophic factor (BDNF) or nerve growth factor. This effect appears to be mediated specifically by p75 NTR , because precursor cells from p75 NTR -deficient mice show a 70% reduction in their neurogenic potential in vitro and fail to respond to BDNF treatment. Furthermore, adult p75 NTR -deficient mice have significantly reduced numbers of PSA-NCAM (polysialylated neural cell adhesion molecule)-positive SVZ neuroblasts in vivo and a lower olfactory bulb weight. Thus, p75 NTR defines a discrete population of highly proliferative SVZ precursor cells that are able to respond to neurotrophin activation by increasing neuroblast generation, making this pathway the most likely mechanism for the increased neurogenesis that accompanies raised BDNF levels in a variety of disease and behavioral situations.
Evidence for cooperative selection of axons for myelination by adjacent oligodendrocytes in the optic nerve
Publisher: Public Library of Science (PLoS)
Date: 09-11-2016
High-Efficiency Pharmacogenetic Ablation of Oligodendrocyte Progenitor Cells in the Adult Mouse CNS
Publisher: Cold Spring Harbor Laboratory
Date: 15-05-2021
DOI: 10.1101/2021.05.13.443012
Abstract: Approaches to investigate adult oligodendrocyte progenitor cells (OPCs) by targeted cell ablation in the rodent central nervous system have been limited by methodological challenges resulting in only partial and transient OPC depletion. We have developed a novel pharmacogenetic model of conditional OPC ablation, eliminating 98.6% of all OPCs throughout the brain. By combining recombinase-based transgenic and viral strategies for targeting OPCs and ventricular-subventricular zone (V-SVZ)-derived neural precursor cells (NPCs), we found new PDGFRA-expressing cells born in the V-SVZ repopulated the OPC-deficient brain starting 12 days after OPC ablation. Our data reveal that OPC depletion induces V-SVZ-derived NPCs to generate vast numbers of PDGFRA + NG2 + cells with the capacity to migrate and proliferate extensively throughout the dorsal anterior forebrain. Further application of this novel approach to ablate OPCs will advance knowledge of the function of both OPCs and oligodendrogenic NPCs in health and disease.
Adult Neural Precursor Cells from the Subventricular Zone Contribute Significantly to Oligodendrocyte Regeneration and Remyelination
Publisher: Society for Neuroscience
Date: 15-10-2014
DOI: 10.1523/JNEUROSCI.3491-13.2014
Abstract: Parenchymal oligodendrocyte progenitor cells (pOPCs) are considered the principal cell type responsible for oligodendrogenesis and remyelinaton in demyelinating diseases. Recent studies have demonstrated that neural precursor cells (NPCs) from the adult subventricular zone (SVZ) can also generate new oligodendrocytes after demyelination. However, the relative contribution of NPCs versus pOPCs to remyelination is unknown. We used in vivo genetic fate mapping to assess the behavior of each progenitor type within the corpus callosi (CCs) of mice subjected to cuprizone-induced demyelination. Nestin-CreER T2 and Pdgfra-CreER T2 transgenic mice were crossed with fluorescent Cre reporter strains to map the fate of NPCs and pOPCs respectively. In cuprizone-challenged mice, substantial numbers of NPCs migrated into the demyelinated CC and contributed to oligodendrogenesis. This capacity was most prominent in rostral regions adjacent to the SVZ where NPC-derived oligodendrocytes significantly outnumbered those generated from pOPCs. Sixty-two percent of all nodes of Ranvier in this region were flanked by at least one paranode generated from an NPC-derived oligodendrocyte. Remarkably, g-ratios (ratio of the axon diameter to the diameter of the axon plus myelin sheath) of myelinated axons in regions subject to significant NPC-derived remyelination were equivalent to those of unchallenged controls, and immunoelectron microscopy revealed that NPC-derived myelin was significantly thicker than that generated by pOPCs, regardless of axonal caliber. We also demonstrate that a reduced efficiency of remyelination in the caudal CC was associated with long-term impairment in the maturation of oligodendrogenic NPCs but only transient delay in pOPC differentiation. Collectively, our data define a major distinct role for NPCs in remyelination, identifying them as a key target for enhancing myelin repair in demyelinating diseases.
Genetic and Physical Interactions betweenMicrophthalmia Transcription Factor and PU.1 Are Necessary for Osteoclast Gene Expression and Differentiation
Publisher: Elsevier BV
Date: 09-2001
Is cell migration or proliferation dominant in the formation of linear arrays of oligodendrocytes?
Publisher: Elsevier BV
Date: 10-2016
DOI: 10.1016/J.JTBI.2016.06.028
Abstract: Oligodendrocytes are the myelin-producing cells of the central nervous system that are responsible for electrically insulating axons to speed the propagation of electrical impulses. A striking feature of oligodendrocyte development within white matter is that the cell bodies of many oligodendrocyte progenitor cells become organised into discrete linear arrays of three or more cells before they differentiate into myelin-producing oligodendrocytes. These linear arrays align parallel to the direction of the axons within white matter tracts and are believed to play an important role in the co-ordination of myelination. Guided by experimental data on the abundance and composition of linear arrays in the corpus callosum of the postnatal mouse brain, we construct discrete and continuous models of linear array generation to specifically investigate the relative influence of cell migration, proliferation, differentiation and death of oligodendroglia upon the genesis of linear arrays during early postnatal development. We demonstrate that only models that incorporate significant cell migration can replicate all of the experimental observations on number of arrays, number of cells in arrays and total cell count of oligodendroglia within a given area of the corpus callosum. These models are also necessary to accurately reflect experimental data on the abundance of linear arrays composed of oligodendrocytes that derive from progenitors of different clonal origins.
Amyloid precursor protein and amyloid precursor‐like protein 2 have distinct roles in modulating myelination, demyelination, and remyelination of axons
Publisher: Wiley
Date: 02-12-2018
DOI: 10.1002/GLIA.23561
Abstract: The identification of factors that regulate myelination provides important insight into the molecular mechanisms that coordinate nervous system development and myelin regeneration after injury. In this study, we investigated the role of amyloid precursor protein (APP) and its paralogue amyloid precursor-like protein 2 (APLP2) in myelination using APP and APLP2 knockout (KO) mice. Given that BACE1 regulates myelination and myelin sheath thickness in both the peripheral and central nervous systems, we sought to determine if APP and APLP2, as alternate BACE1 substrates, also modulate myelination, and therefore provide a better understanding of the events regulating axonal myelination. In the peripheral nervous system, we identified that adult, but not juvenile KO mice, have lower densities of myelinated axons in their sciatic nerves while in the central nervous system, axons within both the optic nerves and corpus callosum of both KO mice were significantly hypomyelinated compared to wild-type (WT) controls. Biochemical analysis demonstrated significant increases in BACE1 and myelin oligodendrocyte glycoprotein and decreased NRG1 and proteolipid protein levels in both KO brain tissue. The acute cuprizone model of demyelination/remyelination revealed that whereas axons in the corpus callosum of WT and APLP2-KO mice underwent similar degrees of demyelination and subsequent remyelination, the myelinated callosal axons in APP-KO mice were less susceptible to cuprizone-induced demyelination and showed a failure in remyelination after cuprizone withdrawal. These data identified APP and APLP2 as modulators of normal myelination and demyelination/remyelination conditions. Deletion of APP and APLP2 identifies novel interplays between the BACE1 substrates in the regulation of myelination.
Migration and Differentiation of Neural Stem Cells Diverted From the Subventricular Zone by an Injectable Self-Assembling β-Peptide Hydrogel
Publisher: Frontiers Media SA
Date: 08-11-2019
Related Organisations
National Institute Of Mental Health
Location: United States of America
Florey Institute Of Neuroscience And Mental Health
Location: Australia
Walter And Eliza Hall Institute Of Medical Research
Location: Australia
Related Funding Activities
ARC Future Fellowships - Grant ID: FT150100207
Start Date: 02-2016
End Date: 01-2020
Amount: $694,085.00
Funder: Australian Research Council
View Funded ActivitySpecial Research Initiatives - Grant ID: SR1101002
Start Date: 07-2011
End Date: 12-2019
Amount: $21,000,000.00
Funder: Australian Research Council
View Funded Activity