ORCID Profile
0000-0001-7053-0355
Current Organisation
Murdoch University
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Publisher: MDPI AG
Date: 21-05-2023
DOI: 10.3390/IJMS24109059
Abstract: The quality and maturation of an oocyte not only play decisive roles in fertilization and embryo success, but also have long-term impacts on the later growth and development of the fetus. Female fertility declines with age, reflecting a decline in oocyte quantity. However, the meiosis of oocytes involves a complex and orderly regulatory process whose mechanisms have not yet been fully elucidated. This review therefore mainly focuses on the regulation mechanism of oocyte maturation, including folliculogenesis, oogenesis, and the interactions between granulosa cells and oocytes, plus in vitro technology and nuclear/cytoplasm maturation in oocytes. Additionally, we have reviewed advances made in the single-cell mRNA sequencing technology related to oocyte maturation in order to improve our understanding of the mechanism of oocyte maturation and to provide a theoretical basis for subsequent research into oocyte maturation.
Publisher: Elsevier BV
Date: 10-2023
Publisher: Elsevier BV
Date: 07-2007
DOI: 10.1016/J.MICRON.2006.07.027
Abstract: Image stitching is the process of combining multiple images to produce a panorama or larger image. In many biomedical studies, including those of cancer and infection, the use of this approach is highly desirable in order to acquire large areas of certain structures or whole sections, while retaining microscopic resolution. In this study, we describe the application of Autostitch, viz. software that is normally used for the generation of panoramas in photography, in the seamless stitching of microscope images. First, we tested this software on image sets manually acquired by normal light microscopy and compared the performance with a manual stitching approach performed with Paint Shop Pro. Secondly, this software was applied to an image stack acquired by an automatic microscope. The stitching results were then compared with that generated by a self-programmed rectangular tiling macro integrated in Image J. Thirdly, this program was applied in the image stitching of images from electron microscopy. Thus, the automatic stitching program described here may find applications in convenient image stitching and virtual microscopy in the biomedical research.
Publisher: Humana Press
Date: 2013
DOI: 10.1007/978-1-62703-411-1_9
Abstract: Combining multicolor fluorescent in situ hybridization (FISH) and immunofluorescent staining (IFS) presents a powerful method for visualizing the spatial relationship between mRNA and proteins in different neural compartments. Although seemingly straightforward, the combination of IFS/FISH and quantitative co-localization analysis of mRNA and proteins can be difficult to perform successfully, often generating variable results. Here we describe a combined method of multicolor IFS and FISH in concert with two-dimensional (2D) and three-dimensional (3D) co-localization analysis for determining the expression of in idual molecules in rat neurons and brain sections. Using this approach, we have analyzed interactions of the Huntington's disease protein huntingtin with select proteins and mRNA.
Publisher: Elsevier BV
Date: 10-2008
DOI: 10.1016/J.MICRON.2007.10.007
Abstract: Peyer's patches (PPs) are typical gut-associated lymphoid tissues that are located along the wall of the small intestine and that serve as the major sites for generation of immunity to intestinal antigens. Their unique micro-organization is crucial for the generation of the immune response. Although many studies have been reported on the functional anatomy of PP, most investigations have relied on the random s ling of these organs, a procedure that is insufficient for the systemic scanning of the whole tissue or organ. By combining a variety of methods, we have accomplished 3D reconstructions of Peyer's patch. The complex reconstruction procedure includes several steps. First, the PP are serially sectioned at a thickness of 10 microm with a cryostat (b) the serial sections are stained with haematoxylin-eosin (c) multiple images from the PP are acquired with an automatic microscope and stitched together with Image Pro Plus to generate a composite image for the whole organ (d) the serial images are reconstructed with Image J, Reconstruct and 3D Studio Max. The combinational approaches that we present here should be of value when extrapolated to the reconstruction of other tissues or organs. Moreover, the 3D model that we have created and our stereological analysis should be extremely helpful for further in vivo microscopic studies of PP with respect to the immune response.
Publisher: Springer Science and Business Media LLC
Date: 17-06-2020
DOI: 10.1038/S41598-020-66619-0
Abstract: The central nervous system regulates the immune system through the secretion of hormones from the pituitary gland and other endocrine organs, while the peripheral nervous system (PNS) communicates with the immune system through local nerve-immune cell interactions, including sympathetic arasympathetic (efferent) and sensory (afferent) innervation to lymphoid tissue/organs. However, the precise mechanisms of this bi-directional crosstalk of the PNS and immune system remain mysterious. To study this kind of bi-directional crosstalk, we performed immunofluorescent staining of neurofilament and confocal microscopy to reveal the distribution of nerve fibers and nerve-immune cell associations inside mouse spleen. Our study demonstrates (i) extensive nerve fibers in all splenic compartments including the splenic nodules, periarteriolar lymphoid sheath, marginal zones, trabeculae, and red pulp (ii) close associations of nerve fibers with blood vessels (including central arteries, marginal sinuses, penicillar arterioles, and splenic sinuses) (iii) close associations of nerve fibers with various subsets of dendritic cells, macrophages (Mac1 + and F4/80 + ), and lymphocytes (B cells, T helper cells, and cytotoxic T cells). Our data concerning the extensive splenic innervation and nerve-immune cell communication will enrich our knowledge of the mechanisms through which the PNS affects the cellular- and humoral-mediated immune responses in healthy and infectious/non-infectious states.
Publisher: Frontiers Media SA
Date: 04-10-2022
DOI: 10.3389/FCIMB.2022.960938
Abstract: Coronavirus disease 2019 (COVID-19) is an extremely contagious illness caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Early disease recognition of COVID-19 is crucial not only for prompt diagnosis and treatment of the patients, but also for effective public health surveillance and response. The reverse transcription-polymerase chain reaction (RT-PCR) is the most common method for the detection of SARS-CoV-2 viral mRNA and is regarded as the gold standard test for COVID-19. However, this test and those for antibodies (IgM and IgG) and antigens have certain limitations (e.g., by yielding false-negative and false-positive results). We have developed an RNA fluorescence in situ hybridization (FISH) method for high-sensitivity detection of SARS-CoV-2 mRNAs in HEK 293T cell cultures as a model. After transfection of HEK 293T cells with plasmids, Spike (S)/envelope (E) proteins and their mRNAs were clearly detected inside the cells. In addition, hybridization time could be reduced to 2 hours for faster detection when probe concentration was increased. Our approach might thus significantly improve the sensitivity and specificity of SARS-CoV-2 detection and be widely applied for the high-sensitivity single-molecular detection of other RNA viruses (e.g., Middle East respiratory syndrome coronavirus (MERS-CoV), Hepatitis A virus, all influenza viruses, and human immunodeficiency virus (HIV)) in various types of s les including tissue, body fluid, blood, and water. RNA FISH can also be utilized for the detection of DNA viruses (e.g., Monkeypox virus, human papillomavirus (HPV), and cytomegalovirus (CMV)) by detection of their mRNAs inside cells or body fluid.
Publisher: Wiley
Date: 31-01-2007
DOI: 10.1111/J.1439-0264.2006.00741.X
Abstract: The blood and lymphatic vascular system of the gut plays an important role in tissue fluid homeostasis, nutrient absorption and immune surveillance. To obtain a better understanding of the anatomic basis of these functions, the blood and lymphatic vasculature of the lower segment of mouse gut and several constituents of gut-associated lymphoid tissue (GALT) including Peyer's patch, specialized lymphoid nodules in the caecum, small lymphoid aggregates and lymphoid nodules in the colon were studied by using confocal microscopy. Additionally, the innervation and nerve/immune cell interactions in the gut and Peyer's patch were investigated by using cell surface marker PGP9.5 and Glial fibrillary acidic protein (GFAP). In the gut and Peyer's patch, the nerves have contact with B cell, T cell and B220CD3 double-positive cells. Dendritic cells, the most important antigen-presenting cells, were closely apposed to some nerves. Some dendritic cells formed membrane-membrane contact with nerve terminals and neuron cell body. Many fine nerve fibres, which are indirectly detected by GFAP, have contact with dendritic cells and other immune cells in the Peyer's patch. Furthermore, the expression of Muscarinic Acetylcholine receptor (subtype M2) was characterized on dendritic cells and other cell population. These findings are expected to provide a route to understand the anatomic basis of neuron-immune regulation/cross-talk and probably neuroinvasion of prion pathogens in the gut and GALT.
Publisher: Elsevier BV
Date: 11-2006
DOI: 10.1016/J.ACTHIS.2006.02.002
Abstract: Multi-colour imaging of immunofluorescently labelled tissue using confocal microscopy was accomplished by using colour addition theory. This new technique includes several improvements for immunolabelling: (1) the co-localization of two or more markers on one cell for the identification of specific cell populations (2) the co-localization of two fluorescent dyes from secondary reagents for the identification of the cells (3) a multi-step staining protocol with two primary antibodies originating from the same host species or with two or three biotin-conjugated primary antibodies. After image acquisition, colour segmentation/unmixing are applied to the single multi-colour image to generate multi-pseudo-channels for in idual or co-localized fluorescent dyes. With this new technique, we have been able to visualize six cell populations simultaneously in the mouse lymph node and intestine. The efficiency of this method has also been demonstrated in the three-dimensional reconstruction of thick sections from mouse ileum. Our method is simple, efficient, and may be indispensable in experimental cell and tissue studies requiring multiple immunolabelling.
Publisher: Wiley
Date: 02-2007
DOI: 10.1002/JEMT.20401
Abstract: Multiple immunofluorescent staining is a powerful strategy for visualizing the spatial and temporal relationship between antigens, cell populations, and tissue components in histological sections. To segment different cell populations from the multicolor image generated by immunostaining based on color addition theory, a systems approach is proposed for automatic segmentation of six colors. After image acquisition and processing, images are automatically segmented with the proposed approach and six-pseudo channels for in idual or colocalized fluorescent dye are generated to distinguish different cell types. The principle of this approach is the classification of each pixel into one of six colors (red, green, blue, yellow, magenta, and cyan) by choosing the minimal angular deviation between the RGB vector of the given pixel and six classically defined edge vectors. In the present infection studies of Listeria monocytogenes, the new multicolor staining methods based on the color addition were applied and the proposed color segmentation was performed for multicolor analysis. Multicolor analysis was accomplished to study the migration and interaction of Listeria and different cell subpopulations such as CD4CD25 double positive T regulatory cells we also visualized simultaneously the B cells, T cells, dendritic cells, macrophages, and Listeria in another experiment. After Listeria infection, ERTR9 macrophages and dendritic cells formed cluster with Listeria in the infection loci. The principle of color addition and the systems approach for segmentation may be widely applicable in infection and immunity studies requiring multicolor imaging and analysis. This approach can also be applied for image analysis in the multicolor in vivo imaging, multicolor FISH or karyotyping or other studies requiring multicolor analysis.
Publisher: Springer Science and Business Media LLC
Date: 03-11-2011
DOI: 10.1038/SREP00140
Publisher: Elsevier BV
Date: 06-2008
DOI: 10.1016/J.MICRON.2007.03.005
Abstract: The first step towards the three-dimensional (3D) reconstruction of histological structures from serial sectioned tissue blocks is the proper alignment of microscope image sequences. We have accomplished an automatic rigid registration program, named Image-Reg, to align serial sections from mouse lymph node and Peyer's patch. Our approach is based on the calculation of the pixel-correlation of objects in adjacent images. The registration process is mainly ided into two steps. Once the foreground images have been segmented from the original images, the first step (primary alignment) is performed on the binary images of segmented objects this process includes rotation by using the moments and translation through the X, Y axes by using the centroid. In the second step, the matching error of two binary images is calculated and the registration results are refined through multi-scale iterations. In order to test the registration performance, Image-Reg has been applied to an image and its transformed (rotated) version and subsequently to an image sequence of three serial sections of mouse lymph node. In addition, to compare our algorithm with other registration methods, three other approaches, viz. manual registration with Reconstruct, semi-automatic landmark registration with Image-Pro Plus and the automatic phase-correlation method with Image-Pro Plus, have also been applied to these three sections. The performance of our program has been also tested on other two-image data sets. These include: (a) two light microscopic images acquired by the automatic microscope (stitched with other software) (b) two images fluorescent images acquired by confocal microscopy (tiled with other software). Our proposed approach provides a fast and accurate linear alignment of serial image sequences for the 3D reconstruction of tissues and organs.
Publisher: Oxford University Press (OUP)
Date: 20-08-2021
Abstract: To reveal the relationship between anti-Golgi antibody (AGA) and clinical diseases through retrospective analysis. The clinical data of 584 cases testing positive for AGA in the past 11 years were collected and retrospectively analyzed. AGA pattern accounted for .2% of positive ANA results. In total, 35.0% of diagnosed patients had autoimmune diseases (AID), mainly rheumatoid arthritis (RA). High-titer AGA (≧1:1000) was common in AID. In nondiagnosed patients with clinical symptoms, joint pain/muscle pain was the most common. Positive AGA with high titer was closely related to RA. Joint pain/muscle pain was the most common symptom in patients who tested AGA positive. Therefore, AGA may be a key indicator of RA in the Chinese population.
Publisher: Elsevier BV
Date: 03-2007
DOI: 10.1016/J.ACTHIS.2006.11.002
Abstract: The function of lymph nodes is greatly influenced by their unique microanatomy, in which distinct subpopulations of cells are compartmentalized by a meshwork of reticular cells and fibres, specialized blood and lymphatic vessels and nerves. Using antibodies against extracellular matrix (ECM) proteins (fibronectin, collagen IV and laminin), proteoglycan (perlecan), and a fibroblastic marker (ERTR-7), the distribution and molecular organization of the system of reticular fibres was investigated by three-dimensional (3D) reconstruction methods. Fibronectin, collagen IV and laminin are restricted to reticular fibres and have a similar distribution pattern, whereas perlecan is limited to the vascular system of the lymph node. Various compartments of the lymph node, such as the B-cell follicle, paracortex (including the high endothelial venules and paracortical cord), and medulla have been reconstructed to visualize their vasculature with respect to B and T cells. Since the morphology of lymph nodes may change significantly in pathological conditions, different compartments of reactive lymph node (after low-dose Listeria monocytogenes infection), especially germinal centres, were also investigated. The data presented here should facilitate our understanding of the 3D organization of non-immune cell components of lymph nodes, which is crucial for cell adhesion, migration, activation, and differentiation in normal and pathological conditions.
Publisher: Elsevier BV
Date: 04-2010
Publisher: Elsevier BV
Date: 03-2009
Publisher: Springer Science and Business Media LLC
Date: 22-06-2019
DOI: 10.1007/S00441-019-03052-4
Abstract: The central nervous system impacts the immune system mainly by regulating the systemic concentration of humoral substances, whereas the peripheral nervous system (PNS) communicates with the immune system specifically according to local "hardwiring" of sympathetic arasympathetic (efferent) and sensory (afferent) nerves to the primary and secondary lymphoid tissue/organs (e.g., thymus spleen and lymph nodes). In the present study, we use immunofluorescent staining of neurofilament-heavy to reveal the distribution of nerve fibers and the nerve-immune cell neighborhood inside the mouse thymus. Our results demonstrate (a) the presence of an extensive meshwork of nerve fibers in all thymic compartments, including the capsule, subcapsular region, cortex, cortico-medullary junction and medulla (b) close associations of nerve fibers with blood vessels (including the postcapillary venules), indicating the neural control of blood circulation and immune cell dynamics inside the thymus (c) the close proximity of nerve fibers to various subsets of thymocytes (e.g., CD4
Publisher: PAGEPress Publications
Date: 18-10-2019
Abstract: The peripheral nervous system communicates specifically with the immune system via local interactions. These interactions include the “hardwiring” of sympathetic arasympathetic (efferent) and sensory nerves (afferent) to primary (e.g., thymus and bone marrow) and secondary (e.g., lymph node, spleen, and gut-associated lymphoid tissue) lymphoid tissue/organs. To gain a better understanding of this bidirectional interaction/crosstalk between the two systems, we have investigated the distribution of nerve fibres and PNS-immune cell associations in situ in the mouse lymph node by using immunofluorescent staining and confocal microscopy/ three-dimensional reconstruction. Our results demonstrate i) the presence of extensive nerve fibres in all compartments (including B cell follicles) in the mouse lymph node ii) close contacts/associations of nerve fibres with blood vessels (including high endothelial venules) and lymphatic vessels/sinuses iii) close contacts/associations of nerve fibres with various subsets of dendritic cells (e.g., B220+CD11c+, CD4+CD11c+, CD8a+CD11c+, and Mac1+CD11c+), Mac1+ macrophages, and B/T lymphocytes. Our novel findings concerning the innervation and nerve-immune cell interactions inside the mouse lymph node should greatly facilitate our understanding of the effects that the peripheral nervous system has on cellular- and humoral-mediated immune responses or vice versa in health and disease.
Publisher: Wiley
Date: 17-09-2020
DOI: 10.1002/JBM.A.36786
Abstract: Prevascularization of tissue constructs before implantation has been developed as a novel and promising concept for successful implantation. Since hypoxia might induce angiogenesis, we have investigated the effects of hypoxic treatment on vascularization by using co-cultures of primary human osteoblasts (POBs) and outgrowth endothelial cells. Our results show that: (a) repeated short-term hypoxia (2% O
Publisher: Elsevier BV
Date: 06-2023
Publisher: Elsevier BV
Date: 09-2023
Publisher: MDPI AG
Date: 31-10-2023
DOI: 10.3390/V15112198
Publisher: Hindawi Limited
Date: 22-07-2022
DOI: 10.1111/JFBC.14329
Abstract: During the implantation of functional tissue-engineered constructs for treating bone defects, a functional vascular network is critical for the survival of the construct. One strategy to achieve rapid angiogenesis for this application is the co-culture of outgrowth endothelial cells (OECs) and primary human osteoblasts (POBs) within a scaffold prior to implantation. In the present study, we aim to investigate whether Astragalus polysaccharide (APS) promotes angiogenesis or vascularization via the TLR4 signaling pathway in a co-culture of OECs and POBs. The co-cultures were treated with various concentrations of APS for 24 h and, subsequently, another 7 days, followed by CD31 staining and analysis of micro-vessel-formation areas using software. Additionally, APS (0.4 mg/ml for 24 h) was added to monocultures of OECs or POBs for evaluating proliferation, apoptosis, angiogenesis, osteogenesis, TLR4 signaling pathway, and inflammatory cytokine release. We found that APS promoted angiogenesis in the co-culture at the optimal concentration of 0.4 mg/ml. TLR4 activation by APS up-regulated the expression level of TLR4/MyD88 and enhanced angiogenesis and osteogenesis in monocultures of OECs and POBs. The levels of E-selectin adhesion molecules, three cytokines (IL-6, TNF-α, and IFN-γ), and VEGF and PDGF-BB, which can induce angiogenesis, increased significantly (p < .05) following APS treatment. Therefore, APS appears to promote angiogenesis and ossification in the co-culture system via the TLR4 signaling pathway. PRACTICAL APPLICATIONS: This study demonstrates that APS may promote angiogenesis and osteocyte proliferation in OEC and POB co-culture systems through the MyD88-dependent TLR4 signaling pathway. APS might represent a potential therapeutic strategy in tissue-engineered bone implantation for the treatment of large bone defects additionally, it has the advantage of safety, as it exhibits low or no side effects. In the future, it is expected to be used in vitro for the construction of tissue-engineered bone and in vivo after implantation in patients with bone defects for promoting rapid vascularization and ossification of tissue-engineered bone and early fusion with the recipient's bone. In addition, as a food additive, Astragalus membranaceus can be used as a tonic material in patients recovering from a fracture for promoting blood-vessel formation at the fracture site and fracture recovery. Combining traditional Chinese medicine with tissue engineering can provide further strategies for promoting the development of regenerative medicine.
Publisher: Elsevier BV
Date: 07-2019
DOI: 10.1016/J.BRAINRESBULL.2019.04.006
Abstract: Although transplantation of bone marrow-derived mesenchymal stem cells (MSCs) has shown beneficial effects on stroke, lower survival of MSCs limits effects. Extracellular regulating kinase 1/2 signaling (ERK1/2) is crucial for cell survival, differentiation, and proliferation. This study was designed to explore whether MSCs modified by over-expressing ERK1/2 may reinforce beneficial effects on stroke in rats. rat MSCs transfected with ERK1/2 and empty lentivirus to generate MSCs overexpressing ERK1/2 (ERK/MSCs) and MSCs (as a control), respectively. In vitro, ERK/MSCs were plated and exposed to glutamate-induced condition, and viability of ERK/MSCs was measured. Furthermore, neural induction of ERK/MSCs was investigated in vitro. Cerebral ischemic rats were induced by occluding middle cerebral artery, and then were stereotaxically injected into ipsilateral right lateral ventricle with ERK/MSCs or MSCs 3 days after stroke and survived for 7 or 14 days after injection. ERK/MSCs showed better viability in physiological and glutamate-induced neurotoxic conditions compared to MSCs. After neural induction, more neurons were be differentiated from ERK/MSCs than from MSCs. After transplantation, more numbers of grafted cells and improved functional recovery were observed in ERK/MSCs-treated rats compared with MSCs-treated rats. Compared with MSCs treatment, ERK/MSCs treatment significantly increased proliferation of neural stem cells in the subventricle zone (SVZ) and the MAP2/nestin double-labeled cells adjacent to the SVZ, enhanced the numbers of reactive astrocytes while suppressed microglial activation. Besides, TNF-α level was elevated in ERK/MSCs-treated rats. ERK/MSCs transplantation showed better functional recovery after stroke in rats, likely in part through enhancing survival of MSCs and possibly by modulating the proliferation, neuronal de-differentiation and neuroinflammation.
Publisher: Hindawi Limited
Date: 24-07-2017
DOI: 10.1002/TERM.2075
Abstract: The development of new approaches leading to fast and successful vascularization of tissue-engineered constructs is one of the most intensively studied subjects in tissue engineering and regenerative medicine. Recently, TLR4 activation and LPS stimulation of endothelial cells have been reported to promote angiogenesis in a variety of settings. In this study, we demonstrate that TLR4 activation by Ultrapure LPS Escherichia coli 0111:B4 (LPS-EB) significantly enhances microvessel formation in a co-culture system consisting of outgrowth endothelial cells (OECs) and primary human osteoblasts (pOBs). The precise modes of TLR4 action on the process of angiogenesis have also been investigated in this study. Using quantitative fluorescence microscopy in monocultures of OECs and pOBs, it was found that TLR4 activation through LPS-EB upregulates the expression level of TLR4/MYD88 and enhances both angiogenesis and osteogenesis. Furthermore, ELISA and qRT-PCR have shown that the level of two adhesion molecules (ICAM-1 and E-selectin), two cytokines (IL-6 and IL-8) and two growth factors (VEGF and PDGF-BB) related to angiogenesis increase significantly after LPS-EB treatment. This increased understanding of the role of TLR4 in angiogenesis could be of value in various settings related to tissue repair and tissue engineering. Moreover, since LPS and TLR4 agonists improve angiogenesis and osteogenesis, TLR4 agonists (endogenous or synthetic) could be used for angiogenesis intervention in vivo and therefore could be tested for their potential clinical applications in promoting angiogenesis in bone tissue engineering. Copyright © 2015 John Wiley & Sons, Ltd.
Publisher: Wiley
Date: 13-05-2019
DOI: 10.1111/FEBS.14865
Abstract: Neuroplastin 65 (Np65) is a brain-specific cell adhesion molecule that is highly expressed in the hippoc us, amygdala, and cortex, regions of the brain that are associated with memory and emotions. However, the role of Np65 in regulation of emotional behavior is still unclear. In the present study, we show that Np65 knock-out (Np65 KO) mice display enhanced anxiety-like behavior, a reduction in some aspects of depressive-like behaviors, and increased sociability and memory. Biochemical investigations revealed that Np65 KO mice show increased adult-born neurons and proliferation in the hippoc us. In addition, the level of 5-hydroxytryptamine (5-HT) in the hippoc us was reduced. The expression of tryptophan hydroxylase 2 in the brainstem and the expression of the 5-HT
Publisher: SAGE Publications
Date: 04-2023
DOI: 10.1177/15353702231171894
Abstract: Prevascularization is crucial for the survival of tissue-engineered bone and further bone repair/regeneration. Since epicatechin gallate (ECG), the most abundant flavanol in green tea, shows potential beneficial effects on endothelial cells and bone cells, we decided to investigate whether it promotes vascularization/angiogenesis and osteogenesis using a co-culture system containing human primary osteoblasts (POBs) and outgrowth endothelial cells (OECs). We found that treatment with ECG (1) significantly enhanced microvessel formation in co-culture of POB and OECs, (2) improved cell viability roliferation and the angiogenic/osteogenic capacities of OEC/POBs, (3) significantly increased the levels of E-selectin, IL-6, TNF-α, IFN-γ, VEGF, and PDGF-BB in co-cultures of POB and OEC, and (4) upregulated HIF-1α, HIF-2α, NF-κB, iNOS, GLUT1, VEGF, and Ang1/2 but downregulated PHD1 in monocultures of OEC or POB. Our findings demonstrate that ECG promotes angiogenesis and osteogenesis (probably via HIF signaling) in co-cultures of OECs and POBs. ECG thus has potential applications in the promotion of angiogenesis/vascularization in many tissue constructs including those of bone.
Publisher: Wiley
Date: 30-05-2012
DOI: 10.1002/CYTO.A.22073
Publisher: Hindawi Limited
Date: 08-2007
DOI: 10.1111/J.1462-5822.2007.00932.X
Abstract: Cholesterol-dependent cytolysins (CDCs) represent a large family of conserved pore-forming toxins produced by several Gram-positive bacteria such as Listeria monocytogenes, Streptococcus pyrogenes and Bacillus anthracis. These toxins trigger a broad range of cellular responses that greatly influence pathogenesis. Using mast cells, we demonstrate that listeriolysin O (LLO), a prototype of CDCs produced by L. monocytogenes, triggers cellular responses such as degranulation and cytokine synthesis in a Ca(2+)-dependent manner. Ca(2+) signalling by LLO is due to Ca(2+) influx from extracellular milieu and release of from intracellular stores. We show that LLO-induced release of Ca(2+) from intracellular stores occurs via at least two mechanisms: (i) activation of intracellular Ca(2+) channels and (ii) a Ca(2+) channels independent mechanism. The former involves PLC-IP(3)R operated Ca(2+) channels activated via G-proteins and protein tyrosine kinases. For the latter, we propose a novel mechanism of intracellular Ca(2+) release involving injury of intracellular Ca(2+) stores such as the endoplasmic reticulum. In addition to Ca(2+) signalling, the discovery that LLO causes damage to an intracellular organelle provides a new perspective in our understanding of how CDCs affect target cells during infection by the respective bacterial pathogens.
Publisher: Springer Science and Business Media LLC
Date: 27-05-2010
Abstract: Studies have implicated reduced levels of brain-derived neurotrophic factor (BDNF) in the pathogenesis of Huntington's disease. Mutant huntingtin (Htt) protein was previously reported to decrease BDNF gene transcription and axonal transport of BDNF. We recently showed that wild-type Htt is associated with the Argonaute 2 microRNA-processing enzyme involved in gene silencing. In dendrites, Htt co-localizes with components of neuronal granules and mRNAs, indicating that it might play a role in post-transcriptional processing/transport of dendritic mRNAs. We conducted imaging experiments in cultured cortical neurons to demonstrate the co-localization of endogenous Htt and BDNF mRNA in fixed cells, and co-trafficking of BDNF 3'UTR mRNA with endogenous and fluorescently tagged Htt in live neurons. We used an enhanced technique that combines FISH and immunofluorescent staining to co-localize BDNF mRNA with Htt, Ago2, CPEB and dynein in thick vibratome sections of the rat cortex. In cultured neurons and sections of the rat cortex, we found BDNF mRNA associated with Htt and components of neuronal RNA granules, which are centers for regulating RNA transport and local translation. Htt may play a role in post-transcriptional transport/targeting of mRNA for BDNF, thus contributing to neurotrophic support and neuron survival.
Publisher: Oxford University Press (OUP)
Date: 12-2006
DOI: 10.1634/STEMCELLS.2006-0109
Abstract: Type 1 diabetes is caused by the destruction of pancreatic beta-cells by T cells of the immune system. Islet transplantation is a promising therapy for diabetes mellitus. Bone marrow stem cells (BMSC) have the capacity to differentiate into various cell lineages including endocrine cells of the pancreas. To investigate the conditions that allow BMSC to differentiate into insulin-producing cells, a novel in vitro method was developed by using the histone deacetylase inhibitor, trichostatin A (TSA). BMSC, cultured in presence of TSA, differentiated into islet-like clusters under appropriate culture conditions. These islet-like clusters were similar to the cells of the islets of the pancreas. The islet-like clusters showed endocrine gene expression typical for pancreatic beta-cell development and function, such as insulin (I and II), glucagon, somatostatin, GLUT-2, pancreatic duodenal homeobox-1 (PDX-1), and Pax 4. Immunocytochemistry confirmed islet-like clusters contained pancreatic hormones. The colocalization of insulin and C-peptide was also observed. Enzyme-linked immunosorbent assay analysis demonstrated that insulin secretion was regulated by glucose. Western blot analysis demonstrated the presence of stored insulin. Electron microscopy of the islet-like cells revealed an ultrastructure similar to that of pancreatic beta-cells, which contain insulin granules within secretory vesicles. These findings suggest that histone-deacetylating agents could allow the differentiation of BMSC into insulin-producing beta-cells.
No related grants have been discovered for Bin Ma.