We investigated nerve growth factor precursor （proNGF） and mature NGF expression in ischemic and non-ischemic cortices after cerebral ischemia-reperfusion injury. In both ischemic and non-ischemic cortices, proNGF w...We investigated nerve growth factor precursor （proNGF） and mature NGF expression in ischemic and non-ischemic cortices after cerebral ischemia-reperfusion injury. In both ischemic and non-ischemic cortices, proNGF was found to be present in the extracellular space and cytoplasm. In addition, mature NGF was expressed in extracellular space, but with a very low signal. In ischemic cortex only, proNGF was significantly decreased, reaching a minimal level at 1 day. Mature NGF was increased at 4 hours, then reached a minimal level at 3 days. The p75 neurotrophin receptor （p75NTR） was significantly decreased after ischemia, and increased at 3 days after ischemia. These results confirmed that proNGF was the predominant form of NGF during the pathological process of cerebral ischemia-repeffusion injury. In addition, our findings suggest that ischemic injury may influence the conversion of proNGF to mature NGF, and that proNGF/p75NTR may be involved in reperfusion injury.展开更多
BACKGROUND： Neuronal apoptosis in perihematomal brain tissues following intracerebral hemorrhage is strongly related to the formation of a compound signal pathway between nerve growth factor precursor （proNGF）, p75...BACKGROUND： Neuronal apoptosis in perihematomal brain tissues following intracerebral hemorrhage is strongly related to the formation of a compound signal pathway between nerve growth factor precursor （proNGF）, p75NTR, and sortilin receptor. Sortilin acts as a co-receptor and molecular switch governing the p75NTR-mediated pro-apoptotic signal induced by proNGF. OBJECTIVE： To investigate proNGF and sortilin expressions in perihematomal brain tissues following intracerebral hemorrhage, and to study the effects of proNGF and sortilin on secondary cell apoptosis. DESIGN, TIME AND SETTING： A paired, comparison study was performed at the Laboratory of Histology and Embryology, Xi＇an Jiaotong University from October 2007 to September 2008. MATERIALS： Brain tissue samples were obtained from 15 patients with intracerebral hemorrhage, who were treated at the Department of Neurosurgery, First Affiliated Hospital, Medical College of Xi＇an Jiaotong University from October 2007 to March 2008. Rabbit anti-proNGF polyclonal antibody was provided by Chemicon, USA; rabbit anti-sortilin polyclonal antibody by Abcam, UK; and TUNEL kit by Promega, USA. METHODS： Perihematomal brain tissues selected 0.5 cm from the hemorrhage area were considered to be the hemorrhage group, while brain tissues from the middle temporal gyrus served as the control group. MAIN OUTCOME MEASURES： Histopathological changes were detected using hematoxylin-eosin staining, cell apoptosis was determined using the TUNEL method, and proNGF and sortilin expressions were determined using immunohistochemistry. RESULTS： Edema was clearly observed in perihematomal brain tissues, and infiltration of inflammatory cells was visible, with the presence of irregular and necrotic bodies. The apoptotic rate in the hemorrhage group was significantly greater than in the control group （P 〈 0.01）. Moreover, sortilin expression significantly increased （P 〈 0.01）, but proNGF expression remained unchanged （P 〉 0.05）. Correlation analysis suggested that sortilin expression positively correlated with apoptosis （rs = 0.648, P 〈 0.01）. CONCLUSION： proNGF expression was stable, but sortilin expression increased in perihematomal brain tissues following intracerebral hemorrhage, suggesting that sortilin acted as a co-receptor and molecular switch to govern p75NTR-mediated cell apoptosis.展开更多
This study demonstrated that brain areas surrounding the site of hematoma following intracerebral hemorrhage are characterized by significantly increased apoptosis and expression of neurotrophin receptor p75 and sorti...This study demonstrated that brain areas surrounding the site of hematoma following intracerebral hemorrhage are characterized by significantly increased apoptosis and expression of neurotrophin receptor p75 and sortilin. However, as detected by terminal deoxynucleotidyl transferase dUTP nick end labeling and immunohistochemical staining, there was no significant change in nerve growth factor precursor expression levels. The appearance of neurotrophin receptor p75 expressing cells was positively correlated with cells that were detected by terminal deoxynucleotidyl transferase dUTP nick end labeling. These findings confirm that the nerve growth factor precursor-neurotrophin receptor p75-sortilin heterotrimeric complex-mediated apoptosis pathway may play an important role in cellular apoptosis following intracerebral hemorrhage.展开更多
A rat model of acute ocular hypertension was established by enhancing the perfusion of balanced salt solution in the anterior chamber of the right eye. Minocycline （90 mg/kg） was administered intraperitoneally into ...A rat model of acute ocular hypertension was established by enhancing the perfusion of balanced salt solution in the anterior chamber of the right eye. Minocycline （90 mg/kg） was administered intraperitoneally into rats immediately after the operation for 3 consecutive days. Immunofluorescence, western blot assay and PCR detection revealed that the expression of the precursor form of nerve growth factor, nerve growth factor and the p75 neurotrophin receptor, and the mRNA expression of nerve growth factor and the p75 neurotrophin receptor, increased after acute ocular hypertension. The number of double-labeled CD11B- and precursor form of nerve growth factor-positive cells, glial fibrillary acidic protein- and p75 neurotrophin receptor-positive cells glial fibrillary acidic protein- and caspase-3-positive cells in the retina markedly increased after acute ocular hypertension. The above-described expression decreased after minocycline treatment. These results suggested that minocycline inhibited the increased expression of the precursor form of nerve growth factor in microglia, the p75 neurotrophin receptor in astroglia, and protected cells from apoptosis.展开更多
In the aftermath of spinal cord injury,glial restricted precursors（GRPs） and immature astrocytes offer the potential to modulate the inflammatory environment of the injured spinal cord and promote host axon regenera...In the aftermath of spinal cord injury,glial restricted precursors（GRPs） and immature astrocytes offer the potential to modulate the inflammatory environment of the injured spinal cord and promote host axon regeneration.Nevertheless clinical application of cellular therapy for the repair of spinal cord injury requires strict quality-assured protocols for large-scale production and preservation that necessitates long-term in vitro expansion.Importantly,such processes have the potential to alter the phenotypic and functional properties and thus therapeutic potential of these cells.Furthermore,clinical use of cellular therapies may be limited by the inflammatory microenvironment of the injured spinal cord,altering the phenotypic and functional properties of grafted cells.This report simulates the process of large-scale GRP production and demonstrates the permissive properties of GRP following long-term in vitro culture.Furthermore,we defined the phenotypic and functional properties of GRP in the presence of inflammatory factors,and call attention to the importance of the microenvironment of grafted cells,underscoring the importance of modulating the environment of the injured spinal cord.展开更多
Endogenous neural stem cells become ＂activated＂ after neuronal injury, but the activation sequence and fate of endogenous neural stem cells in focal cerebral ischemia model are little known. We evaluated the relatio...Endogenous neural stem cells become ＂activated＂ after neuronal injury, but the activation sequence and fate of endogenous neural stem cells in focal cerebral ischemia model are little known. We evaluated the relationships between neural stem cells and hypoxia-inducible factor-1α and vascular endothelial growth factor expression in a photothromobotic rat stroke model using immunohistochemistry and western blot analysis. We also evaluated the chronological changes of neural stem cells by 5-bromo-2′-deoxyuridine（BrdU） incorporation. Hypoxia-inducible factor-1α expression was initially increased from 1 hour after ischemic injury, followed by vascular endothelial growth factor expression. Hypoxia-inducible factor-1α immunoreactivity was detected in the ipsilateral cortical neurons of the infarct core and peri-infarct area. Vascular endothelial growth factor immunoreactivity was detected in bilateral cortex, but ipsilateral cortex staining intensity and numbers were greater than the contralateral cortex. Vascular endothelial growth factor immunoreactive cells were easily found along the peri-infarct area 12 hours after focal cerebral ischemia. The expression of nestin increased throughout the microvasculature in the ischemic core and the peri-infarct area in all experimental rats after 24 hours of ischemic injury. Nestin immunoreactivity increased in the subventricular zone during 12 hours to 3 days, and prominently increased in the ipsilateral cortex between 3–7 days. Nestin-labeled cells showed dual differentiation with microvessels near the infarct core and reactive astrocytes in the peri-infarct area. BrdU-labeled cells were increased gradually from day 1 in the ipsilateral subventricular zone and cortex, and numerous BrdU-labeled cells were observed in the peri-infarct area and non-lesioned cortex at 3 days. BrdU-labeled cells rather than neurons, were mainly co-labeled with nestin and GFAP. Early expressions of hypoxia-inducible factor-1α and vascular endothelial growth factor after ischemia made up the microenvironment to increase the neuronal plasticity of activated endogenous neural stem cells. Moreover, neural precursor cells after large-scale cortical injury could be recruited from the cortex nearby infarct core and subventricular zone.展开更多
AIM:To clarify the mechanism by which bone marrow cells promote angiogenesis around transplanted islets.METHODS: Streptozotocin induced diabetic BALB/ c mice were transplanted syngeneically under the kidney capsule wi...AIM:To clarify the mechanism by which bone marrow cells promote angiogenesis around transplanted islets.METHODS: Streptozotocin induced diabetic BALB/ c mice were transplanted syngeneically under the kidney capsule with the following: (1) 200 islets (islet group: n=12), (2) 1-5×106 bone marrow cells (bone marrow group: n=11), (3) 200 islets and 1-5×106 bone marrow cells (islet + bone marrow group: n= 13), or (4) no cells (sham group:n=5). All mice were evaluated for blood glucose, serum insulin, serum nervegrowth factor (NGF) and glucose tolerance (GTT) up to postoperative day (POD) 14. Histological assessment for insulin, von Willebrand factor (vWF) and NGF was performed at POD 3, 7 and 14.RESULTS: Blood glucose level was lowest and serum insulin was highest in the islet + bone marrow group. Serum NGF increased in islet, bone marrow, and islet + bone marrow groups after transplantation, and there was a significant difference (P=0.0496, ANOVA) between the bone marrow and sham groups. The number of vessels within the graft area was signif icantly increased in both the bone marrow and islet + bone marrow groups at POD 14 as compared to the islet alone group (21.2 ± 3.6 in bone marrow, P=0.01, vs islet group, 22.6 ± 1.9 in islet + bone marrow, P = 0.0003, vs islet group, 5.3 ± 1.6 in islet-alone transplants). NGF was more strongly expressed in bone marrow cells compared with islets. CONCLUSION: Bone marrow cells produce NGF and promote angiogenesis. Islet co-transplantation with bone marrow is associated with improvement of islet graft function.展开更多
ased on the empirical formulation formed from coda observations, the digital waveforms from 33 local events with magnitude ML ranging between 2.1 and 3.5, recorded at Changli station of Beijing Telemetered Seismograph...ased on the empirical formulation formed from coda observations, the digital waveforms from 33 local events with magnitude ML ranging between 2.1 and 3.5, recorded at Changli station of Beijing Telemetered Seismographic Network from 1989 to 1991, are used to compute coda Q for the Changli region and the source factors of all earthquakes by single-station coda method. Furthermore, assuming a certain source model, we have obtained the station site frequency response and source spectra, as well as source parameters such as corner frequencies, seismic moments and stress drops and so on. Their variations with time are monitored before and after larger earthquakes. Because the coda method can more effectively reduce the influence of source radiation pattern and a particular propagation path than direct wave method, more data can be used and more accurate results can be obtained, which provided a possible approach to study the source properties and reveal the variation of source parameters before larger earthquakes.展开更多
Brain-derived neurotrophic factor(BDNF)has robust effects on synaptogenesis,neuronal differentiation and synaptic transmission and plasticity.The maturation of BDNF is a complex process.Proprotein convertase 1/3(PC1/3...Brain-derived neurotrophic factor(BDNF)has robust effects on synaptogenesis,neuronal differentiation and synaptic transmission and plasticity.The maturation of BDNF is a complex process.Proprotein convertase 1/3(PC1/3)has a key role in the cleavage of protein precursors that are directed to regulated secretory pathways;however,it is not clear whether PC1/3 mediates the change in BDNF levels caused by ischemia.To clarify the role of PC1/3 in BDNF maturation in ischemic cortical neurons,primary cortical neurons from fetal rats were cultured in a humidified environment of 95%N_2 and 5%CO_2 in a glucose-free Dulbecco's modified Eagle's medium at 37℃for3 hours.Enzyme-linked immunosorbent assays and western blotting showed that after oxygen-glucose deprivation,the secreted and intracellular levels of BDNF were significantly reduced and the intracellular level of PC1/3 was decreased.Transient transfection of cortical neurons with a PC1/3 overexpression plasmid followed by oxygen-glucose deprivation resulted in increased PC1/3 levels and increased BDNF levels.When levels of the BDNF precursor protein were reduced,the concentration of BDNF in the culture medium was increased.These results indicate that PC 1/3 cleavage of BDNF is critical for the conversion of pro-BDNF in rat cortical neurons during ischemia.The study was approved by the Animal Ethics Committee of Wuhan University School of Basic Medical Sciences.展开更多
Previous studies have shown that proliferation of endogenous neural precursor cells cannot alone compensate for the damage to neurons and axons. From the perspective of neural plastici- ty, we observed the effects of ...Previous studies have shown that proliferation of endogenous neural precursor cells cannot alone compensate for the damage to neurons and axons. From the perspective of neural plastici- ty, we observed the effects of functional electrical stimulation treatment on endogenous neural precursor cell proliferation and expression of basic fibroblast growth factor and epidermal growth factor in the rat brain on the infarct side. Functional electrical stimulation was performed in rat models of acute middle cerebral artery occlusion. Simultaneously, we set up a placebo stimulation group and a sham-operated group. Immunohistochemical staining showed that, at 7 and 14 days, compared with the placebo group, the numbers of nestin （a neural precursor cell marker）-positive cells in the subgranular zone and subventricular zone were increased in the functional electrical stimulation treatment group. Western blot assays and reverse-transcription PCR showed that total protein levels and gene expression of epidermal growth factor and basic fibroblast growth factor were also upregulated on the infarct side. Prehensile traction test results showed that, at 14 days, prehension function of rats in the functional electrical stimulation group was significantly better than in the placebo group. These results suggest that functional electrical stimulation can promote endogenous neural precursor cell proliferation in the brains of acute cerebral infarction rats, enhance expression of basic fibroblast growth factor and epidermal growth factor, and improve the motor function of rats.展开更多
Glial cell line-derived neurotrophic factor(GDNF) plays a critical role in neuronal survival and function. GDNF has two major splice variants in the brain,α-pro-GDNF and β-pro-GDNF, and both isoforms have strong neu...Glial cell line-derived neurotrophic factor(GDNF) plays a critical role in neuronal survival and function. GDNF has two major splice variants in the brain,α-pro-GDNF and β-pro-GDNF, and both isoforms have strong neuroprotective effects on dopamine neurons. However, the expression of the GDNF splice variants in dopaminergic neurons in the brain remains unclear. Therefore, in this study, we investigated the mRNA and protein expression of α-and β-pro-GDNF in the mouse brain by real-time quantitative polymerase chain reaction, using splice variant-specific primers, and western blot analysis. At the mRNA level,β-pro-GDNF expression was significantly greater than that of α-pro-GDNF in the mouse brain. In contrast, at the protein level,α-pro-GDNF expression was markedly greater than that of β-pro-GDNF. To clarify the mechanism underlying this inverse relationship in mRNA and protein expression levels of the GDNF splice variants, we analyzed the expression of sorting protein-related receptor with A-type repeats(SorLA) by real-time quantitative polymerase chain reaction. At the mRNA level, SorLA was positively associated with β-pro-GDNF expression, but not with α-pro-GDNF expression. This suggests that the differential expression of α-and β-pro-GDNF in the mouse brain is related to SorLA expression. As a sorting protein, SorLA could contribute to the inverse relationship among the mRNA and protein levels of the GDNF isoforms. This study was approved by the Animal Ethics Committee of Xuzhou Medical University, China on July 14, 2016.展开更多
The difference between Noggin and basic fibroblast growth factor for the neural precursor differen- tiation from human embryonic stem cells has not been studied. In this study, 100 tJg/L Noggin or 20 IJg/L basic fibro...The difference between Noggin and basic fibroblast growth factor for the neural precursor differen- tiation from human embryonic stem cells has not been studied. In this study, 100 tJg/L Noggin or 20 IJg/L basic fibroblast growth factor in serum-free neural induction medium was used to differen- tiate human embryonic stem cells H14 into neural precursors using monolayer differentiation. Two weeks after induction, significantly higher numbers of neural rosettes formed in the Noggin-induced group than the basic fibroblast growth factor-induced group, as detected by phase contrast micro- scope. Immunofluorescence staining revealed expression levels of Nestin, [3-111 Tubulin and Sox-1 were higher in the induced cells and reverse-transcription PCR showed induced cells expressed Nestin, Sox-1 and Neurofilament mRNA. Protein and mRNA expression in the Noggin-induced group was increased compared with the basic fibroblast growth factor-induced group. Noggin has a greater effect than basic fibroblast growth factor on the induction of human embryonic stem cell differentiation into neural precursors by monolayer differentiation, as Noggin accelerates and in- creases the differentiation of neural precursors.展开更多
Platelet-derived growth factor receptor alpha （PDGFRct） is a marker of oligodendrocyte precursor cells in the central nervous system. NG2 is also considered a marker of oligodendrocyte precursor cells. However, whet...Platelet-derived growth factor receptor alpha （PDGFRct） is a marker of oligodendrocyte precursor cells in the central nervous system. NG2 is also considered a marker of oligodendrocyte precursor cells. However, whether there are differences in the distribution and morphol- ogy of oligodendrocyte precursor cells labeled by NG2 or PDGFRa in the developing neonatal rat brain remains unclear. In this study, by immunohistochemical staining, NG2 positive （NG2＋） cells were ubiquitous in the molecular layer, external pyramidal layer, internal pyramidal layer, and polymorphic layer of the cerebral cortex, and corpus callosum, external capsule, piriform cortex, and medial septal nucleus. NG2~ cells were stellate or fusiform in shape with long processes that were progressively decreased and shortened over the course of brain development. The distribution and morphology of PDGFRct positive （PDGFRa＋） cells were coincident with NG2＋ cells. The co- localization of NG2 and PDGFRu in the cell bodies and processes of some cells was confirmed by double immunofluorescence labeling. Moreover, cells double-labeled for NG2 and PDGFRa were predominantly in the early postnatal stage of development. The numbers of NG2＋/PDGFRa＋ cells and PDGFRa＋ cells decreased, but the number of NG2＋ cells increased from postnatal days 3 to 14 in the developing brain. In addition, amoeboid microglial cells of the corpus callosum, newborn brain macrophages in the normal developing brain, did not express NG2 or PDGFRu, but NG2 expression was detected in amoeboid microglia after hypoxia. The present results suggest that NG2 and PDGFRct are specific markers of oligodendrocyte precursor cells at different stages during early development. Additionally, the NG2 protein is involved in inflammatory and pathological processes of amoeboid microglial cells.展开更多
Alzheimer＇s disease is closely associated with disorders of neurogenesis in the brain, and growing evidence supports the involvement of immunological mechanisms in the development of the disease. However, at present,...Alzheimer＇s disease is closely associated with disorders of neurogenesis in the brain, and growing evidence supports the involvement of immunological mechanisms in the development of the disease. However, at present, the role of T cells in neuronal regeneration in the brain is unknown. We injected amyloid-beta 1-42 peptide into the hippocampus of six BALB/c wild-type mice and six BALB/c-nude mice with T-cell immunodeficiency to establish an animal model of Alzhei- mer＇s disease. A further six mice of each genotype were injected with same volume of normal saline. Immunohistochemistry revealed that the number of regenerated neural progenitor cells in the hippocampus of BALB/c wild-type mice was significantly higher than that in BALB/c-nude mice. Quantitative fluorescence PCR assay showed that the expression levels of peripheral T cell-associated cytokines （interleukin-2, interferon-y） and hippocampal microglia-related cyto- kines （interleukin-113, tumor necrosis factor-a） correlated with the number of regenerated neural progenitor cells in the hippocampus. These results indicate that T cells promote hippocampal neurogenesis in Alzheimer＇s disease and T-cell immunodeficiency restricts neuronal regeneration in the hippocampus. The mechanism underlying the promotion of neuronal regeneration by T cells is mediated by an increased expression of peripheral T cells and central microglial cytokines in Alzheimer＇s disease mice. Our findings provide an experimental basis for understanding the role of T cells in Alzheimer＇s disease.展开更多
基金the National High Technology Program of China (863 Programs), No. 2006AA02A117
文摘We investigated nerve growth factor precursor （proNGF） and mature NGF expression in ischemic and non-ischemic cortices after cerebral ischemia-reperfusion injury. In both ischemic and non-ischemic cortices, proNGF was found to be present in the extracellular space and cytoplasm. In addition, mature NGF was expressed in extracellular space, but with a very low signal. In ischemic cortex only, proNGF was significantly decreased, reaching a minimal level at 1 day. Mature NGF was increased at 4 hours, then reached a minimal level at 3 days. The p75 neurotrophin receptor （p75NTR） was significantly decreased after ischemia, and increased at 3 days after ischemia. These results confirmed that proNGF was the predominant form of NGF during the pathological process of cerebral ischemia-repeffusion injury. In addition, our findings suggest that ischemic injury may influence the conversion of proNGF to mature NGF, and that proNGF/p75NTR may be involved in reperfusion injury.
基金Scientific and Technological Research Developing Program of Shaanxi Province, No. 2007K15-01
文摘BACKGROUND： Neuronal apoptosis in perihematomal brain tissues following intracerebral hemorrhage is strongly related to the formation of a compound signal pathway between nerve growth factor precursor （proNGF）, p75NTR, and sortilin receptor. Sortilin acts as a co-receptor and molecular switch governing the p75NTR-mediated pro-apoptotic signal induced by proNGF. OBJECTIVE： To investigate proNGF and sortilin expressions in perihematomal brain tissues following intracerebral hemorrhage, and to study the effects of proNGF and sortilin on secondary cell apoptosis. DESIGN, TIME AND SETTING： A paired, comparison study was performed at the Laboratory of Histology and Embryology, Xi＇an Jiaotong University from October 2007 to September 2008. MATERIALS： Brain tissue samples were obtained from 15 patients with intracerebral hemorrhage, who were treated at the Department of Neurosurgery, First Affiliated Hospital, Medical College of Xi＇an Jiaotong University from October 2007 to March 2008. Rabbit anti-proNGF polyclonal antibody was provided by Chemicon, USA; rabbit anti-sortilin polyclonal antibody by Abcam, UK; and TUNEL kit by Promega, USA. METHODS： Perihematomal brain tissues selected 0.5 cm from the hemorrhage area were considered to be the hemorrhage group, while brain tissues from the middle temporal gyrus served as the control group. MAIN OUTCOME MEASURES： Histopathological changes were detected using hematoxylin-eosin staining, cell apoptosis was determined using the TUNEL method, and proNGF and sortilin expressions were determined using immunohistochemistry. RESULTS： Edema was clearly observed in perihematomal brain tissues, and infiltration of inflammatory cells was visible, with the presence of irregular and necrotic bodies. The apoptotic rate in the hemorrhage group was significantly greater than in the control group （P 〈 0.01）. Moreover, sortilin expression significantly increased （P 〈 0.01）, but proNGF expression remained unchanged （P 〉 0.05）. Correlation analysis suggested that sortilin expression positively correlated with apoptosis （rs = 0.648, P 〈 0.01）. CONCLUSION： proNGF expression was stable, but sortilin expression increased in perihematomal brain tissues following intracerebral hemorrhage, suggesting that sortilin acted as a co-receptor and molecular switch to govern p75NTR-mediated cell apoptosis.
基金the Science and Technology Research and Development Program of Shaanxi Province, No. 2007K15-01
文摘This study demonstrated that brain areas surrounding the site of hematoma following intracerebral hemorrhage are characterized by significantly increased apoptosis and expression of neurotrophin receptor p75 and sortilin. However, as detected by terminal deoxynucleotidyl transferase dUTP nick end labeling and immunohistochemical staining, there was no significant change in nerve growth factor precursor expression levels. The appearance of neurotrophin receptor p75 expressing cells was positively correlated with cells that were detected by terminal deoxynucleotidyl transferase dUTP nick end labeling. These findings confirm that the nerve growth factor precursor-neurotrophin receptor p75-sortilin heterotrimeric complex-mediated apoptosis pathway may play an important role in cellular apoptosis following intracerebral hemorrhage.
文摘A rat model of acute ocular hypertension was established by enhancing the perfusion of balanced salt solution in the anterior chamber of the right eye. Minocycline （90 mg/kg） was administered intraperitoneally into rats immediately after the operation for 3 consecutive days. Immunofluorescence, western blot assay and PCR detection revealed that the expression of the precursor form of nerve growth factor, nerve growth factor and the p75 neurotrophin receptor, and the mRNA expression of nerve growth factor and the p75 neurotrophin receptor, increased after acute ocular hypertension. The number of double-labeled CD11B- and precursor form of nerve growth factor-positive cells, glial fibrillary acidic protein- and p75 neurotrophin receptor-positive cells glial fibrillary acidic protein- and caspase-3-positive cells in the retina markedly increased after acute ocular hypertension. The above-described expression decreased after minocycline treatment. These results suggested that minocycline inhibited the increased expression of the precursor form of nerve growth factor in microglia, the p75 neurotrophin receptor in astroglia, and protected cells from apoptosis.
基金supported by NIH PO1 NS055976,CraigH.Neilsen Foundation
文摘In the aftermath of spinal cord injury,glial restricted precursors（GRPs） and immature astrocytes offer the potential to modulate the inflammatory environment of the injured spinal cord and promote host axon regeneration.Nevertheless clinical application of cellular therapy for the repair of spinal cord injury requires strict quality-assured protocols for large-scale production and preservation that necessitates long-term in vitro expansion.Importantly,such processes have the potential to alter the phenotypic and functional properties and thus therapeutic potential of these cells.Furthermore,clinical use of cellular therapies may be limited by the inflammatory microenvironment of the injured spinal cord,altering the phenotypic and functional properties of grafted cells.This report simulates the process of large-scale GRP production and demonstrates the permissive properties of GRP following long-term in vitro culture.Furthermore,we defined the phenotypic and functional properties of GRP in the presence of inflammatory factors,and call attention to the importance of the microenvironment of grafted cells,underscoring the importance of modulating the environment of the injured spinal cord.
基金supported by the National Research Foundation of Korea Grant funded by the Korean Government,No.NRF-013-2011-1-E00045
文摘Endogenous neural stem cells become ＂activated＂ after neuronal injury, but the activation sequence and fate of endogenous neural stem cells in focal cerebral ischemia model are little known. We evaluated the relationships between neural stem cells and hypoxia-inducible factor-1α and vascular endothelial growth factor expression in a photothromobotic rat stroke model using immunohistochemistry and western blot analysis. We also evaluated the chronological changes of neural stem cells by 5-bromo-2′-deoxyuridine（BrdU） incorporation. Hypoxia-inducible factor-1α expression was initially increased from 1 hour after ischemic injury, followed by vascular endothelial growth factor expression. Hypoxia-inducible factor-1α immunoreactivity was detected in the ipsilateral cortical neurons of the infarct core and peri-infarct area. Vascular endothelial growth factor immunoreactivity was detected in bilateral cortex, but ipsilateral cortex staining intensity and numbers were greater than the contralateral cortex. Vascular endothelial growth factor immunoreactive cells were easily found along the peri-infarct area 12 hours after focal cerebral ischemia. The expression of nestin increased throughout the microvasculature in the ischemic core and the peri-infarct area in all experimental rats after 24 hours of ischemic injury. Nestin immunoreactivity increased in the subventricular zone during 12 hours to 3 days, and prominently increased in the ipsilateral cortex between 3–7 days. Nestin-labeled cells showed dual differentiation with microvessels near the infarct core and reactive astrocytes in the peri-infarct area. BrdU-labeled cells were increased gradually from day 1 in the ipsilateral subventricular zone and cortex, and numerous BrdU-labeled cells were observed in the peri-infarct area and non-lesioned cortex at 3 days. BrdU-labeled cells rather than neurons, were mainly co-labeled with nestin and GFAP. Early expressions of hypoxia-inducible factor-1α and vascular endothelial growth factor after ischemia made up the microenvironment to increase the neuronal plasticity of activated endogenous neural stem cells. Moreover, neural precursor cells after large-scale cortical injury could be recruited from the cortex nearby infarct core and subventricular zone.
基金Supported by National Institutes of Health/National Instituteof Diabetes and Digestive and Kidney Diseases (NIH/NIDDK)Grant # 1R01-DK077541 (to Hathout E)a grant from the National Medical Test Bed (to Hathout E)
文摘AIM:To clarify the mechanism by which bone marrow cells promote angiogenesis around transplanted islets.METHODS: Streptozotocin induced diabetic BALB/ c mice were transplanted syngeneically under the kidney capsule with the following: (1) 200 islets (islet group: n=12), (2) 1-5×106 bone marrow cells (bone marrow group: n=11), (3) 200 islets and 1-5×106 bone marrow cells (islet + bone marrow group: n= 13), or (4) no cells (sham group:n=5). All mice were evaluated for blood glucose, serum insulin, serum nervegrowth factor (NGF) and glucose tolerance (GTT) up to postoperative day (POD) 14. Histological assessment for insulin, von Willebrand factor (vWF) and NGF was performed at POD 3, 7 and 14.RESULTS: Blood glucose level was lowest and serum insulin was highest in the islet + bone marrow group. Serum NGF increased in islet, bone marrow, and islet + bone marrow groups after transplantation, and there was a significant difference (P=0.0496, ANOVA) between the bone marrow and sham groups. The number of vessels within the graft area was signif icantly increased in both the bone marrow and islet + bone marrow groups at POD 14 as compared to the islet alone group (21.2 ± 3.6 in bone marrow, P=0.01, vs islet group, 22.6 ± 1.9 in islet + bone marrow, P = 0.0003, vs islet group, 5.3 ± 1.6 in islet-alone transplants). NGF was more strongly expressed in bone marrow cells compared with islets. CONCLUSION: Bone marrow cells produce NGF and promote angiogenesis. Islet co-transplantation with bone marrow is associated with improvement of islet graft function.
文摘ased on the empirical formulation formed from coda observations, the digital waveforms from 33 local events with magnitude ML ranging between 2.1 and 3.5, recorded at Changli station of Beijing Telemetered Seismographic Network from 1989 to 1991, are used to compute coda Q for the Changli region and the source factors of all earthquakes by single-station coda method. Furthermore, assuming a certain source model, we have obtained the station site frequency response and source spectra, as well as source parameters such as corner frequencies, seismic moments and stress drops and so on. Their variations with time are monitored before and after larger earthquakes. Because the coda method can more effectively reduce the influence of source radiation pattern and a particular propagation path than direct wave method, more data can be used and more accurate results can be obtained, which provided a possible approach to study the source properties and reveal the variation of source parameters before larger earthquakes.
基金supported by the National Nature Science Foundation of China,No.81501053(to YC)
文摘Brain-derived neurotrophic factor(BDNF)has robust effects on synaptogenesis,neuronal differentiation and synaptic transmission and plasticity.The maturation of BDNF is a complex process.Proprotein convertase 1/3(PC1/3)has a key role in the cleavage of protein precursors that are directed to regulated secretory pathways;however,it is not clear whether PC1/3 mediates the change in BDNF levels caused by ischemia.To clarify the role of PC1/3 in BDNF maturation in ischemic cortical neurons,primary cortical neurons from fetal rats were cultured in a humidified environment of 95%N_2 and 5%CO_2 in a glucose-free Dulbecco's modified Eagle's medium at 37℃for3 hours.Enzyme-linked immunosorbent assays and western blotting showed that after oxygen-glucose deprivation,the secreted and intracellular levels of BDNF were significantly reduced and the intracellular level of PC1/3 was decreased.Transient transfection of cortical neurons with a PC1/3 overexpression plasmid followed by oxygen-glucose deprivation resulted in increased PC1/3 levels and increased BDNF levels.When levels of the BDNF precursor protein were reduced,the concentration of BDNF in the culture medium was increased.These results indicate that PC 1/3 cleavage of BDNF is critical for the conversion of pro-BDNF in rat cortical neurons during ischemia.The study was approved by the Animal Ethics Committee of Wuhan University School of Basic Medical Sciences.
基金the National Natural Science Foundation of China,grants No.30772304,30973166,and 81171863
文摘Previous studies have shown that proliferation of endogenous neural precursor cells cannot alone compensate for the damage to neurons and axons. From the perspective of neural plastici- ty, we observed the effects of functional electrical stimulation treatment on endogenous neural precursor cell proliferation and expression of basic fibroblast growth factor and epidermal growth factor in the rat brain on the infarct side. Functional electrical stimulation was performed in rat models of acute middle cerebral artery occlusion. Simultaneously, we set up a placebo stimulation group and a sham-operated group. Immunohistochemical staining showed that, at 7 and 14 days, compared with the placebo group, the numbers of nestin （a neural precursor cell marker）-positive cells in the subgranular zone and subventricular zone were increased in the functional electrical stimulation treatment group. Western blot assays and reverse-transcription PCR showed that total protein levels and gene expression of epidermal growth factor and basic fibroblast growth factor were also upregulated on the infarct side. Prehensile traction test results showed that, at 14 days, prehension function of rats in the functional electrical stimulation group was significantly better than in the placebo group. These results suggest that functional electrical stimulation can promote endogenous neural precursor cell proliferation in the brains of acute cerebral infarction rats, enhance expression of basic fibroblast growth factor and epidermal growth factor, and improve the motor function of rats.
基金supported by the National Natural Science Foundation of China,No.81772688(to DSG)the Postdoctoral Science Foundation of Jiangsu Province of China,No.1202119C(to HL)
文摘Glial cell line-derived neurotrophic factor(GDNF) plays a critical role in neuronal survival and function. GDNF has two major splice variants in the brain,α-pro-GDNF and β-pro-GDNF, and both isoforms have strong neuroprotective effects on dopamine neurons. However, the expression of the GDNF splice variants in dopaminergic neurons in the brain remains unclear. Therefore, in this study, we investigated the mRNA and protein expression of α-and β-pro-GDNF in the mouse brain by real-time quantitative polymerase chain reaction, using splice variant-specific primers, and western blot analysis. At the mRNA level,β-pro-GDNF expression was significantly greater than that of α-pro-GDNF in the mouse brain. In contrast, at the protein level,α-pro-GDNF expression was markedly greater than that of β-pro-GDNF. To clarify the mechanism underlying this inverse relationship in mRNA and protein expression levels of the GDNF splice variants, we analyzed the expression of sorting protein-related receptor with A-type repeats(SorLA) by real-time quantitative polymerase chain reaction. At the mRNA level, SorLA was positively associated with β-pro-GDNF expression, but not with α-pro-GDNF expression. This suggests that the differential expression of α-and β-pro-GDNF in the mouse brain is related to SorLA expression. As a sorting protein, SorLA could contribute to the inverse relationship among the mRNA and protein levels of the GDNF isoforms. This study was approved by the Animal Ethics Committee of Xuzhou Medical University, China on July 14, 2016.
基金sponsored by Shanghai Key Projects of Basic Research,No.08JC1413900
文摘The difference between Noggin and basic fibroblast growth factor for the neural precursor differen- tiation from human embryonic stem cells has not been studied. In this study, 100 tJg/L Noggin or 20 IJg/L basic fibroblast growth factor in serum-free neural induction medium was used to differen- tiate human embryonic stem cells H14 into neural precursors using monolayer differentiation. Two weeks after induction, significantly higher numbers of neural rosettes formed in the Noggin-induced group than the basic fibroblast growth factor-induced group, as detected by phase contrast micro- scope. Immunofluorescence staining revealed expression levels of Nestin, [3-111 Tubulin and Sox-1 were higher in the induced cells and reverse-transcription PCR showed induced cells expressed Nestin, Sox-1 and Neurofilament mRNA. Protein and mRNA expression in the Noggin-induced group was increased compared with the basic fibroblast growth factor-induced group. Noggin has a greater effect than basic fibroblast growth factor on the induction of human embryonic stem cell differentiation into neural precursors by monolayer differentiation, as Noggin accelerates and in- creases the differentiation of neural precursors.
基金supported by grants from the National Natural Science Foundation of China,No.31100769
文摘Platelet-derived growth factor receptor alpha （PDGFRct） is a marker of oligodendrocyte precursor cells in the central nervous system. NG2 is also considered a marker of oligodendrocyte precursor cells. However, whether there are differences in the distribution and morphol- ogy of oligodendrocyte precursor cells labeled by NG2 or PDGFRa in the developing neonatal rat brain remains unclear. In this study, by immunohistochemical staining, NG2 positive （NG2＋） cells were ubiquitous in the molecular layer, external pyramidal layer, internal pyramidal layer, and polymorphic layer of the cerebral cortex, and corpus callosum, external capsule, piriform cortex, and medial septal nucleus. NG2~ cells were stellate or fusiform in shape with long processes that were progressively decreased and shortened over the course of brain development. The distribution and morphology of PDGFRct positive （PDGFRa＋） cells were coincident with NG2＋ cells. The co- localization of NG2 and PDGFRu in the cell bodies and processes of some cells was confirmed by double immunofluorescence labeling. Moreover, cells double-labeled for NG2 and PDGFRa were predominantly in the early postnatal stage of development. The numbers of NG2＋/PDGFRa＋ cells and PDGFRa＋ cells decreased, but the number of NG2＋ cells increased from postnatal days 3 to 14 in the developing brain. In addition, amoeboid microglial cells of the corpus callosum, newborn brain macrophages in the normal developing brain, did not express NG2 or PDGFRu, but NG2 expression was detected in amoeboid microglia after hypoxia. The present results suggest that NG2 and PDGFRct are specific markers of oligodendrocyte precursor cells at different stages during early development. Additionally, the NG2 protein is involved in inflammatory and pathological processes of amoeboid microglial cells.
基金supported by the National Natural Science Foundation of China,No.30840073the Medical Science Foundation of Guangdong Province,No.A2012298
文摘Alzheimer＇s disease is closely associated with disorders of neurogenesis in the brain, and growing evidence supports the involvement of immunological mechanisms in the development of the disease. However, at present, the role of T cells in neuronal regeneration in the brain is unknown. We injected amyloid-beta 1-42 peptide into the hippocampus of six BALB/c wild-type mice and six BALB/c-nude mice with T-cell immunodeficiency to establish an animal model of Alzhei- mer＇s disease. A further six mice of each genotype were injected with same volume of normal saline. Immunohistochemistry revealed that the number of regenerated neural progenitor cells in the hippocampus of BALB/c wild-type mice was significantly higher than that in BALB/c-nude mice. Quantitative fluorescence PCR assay showed that the expression levels of peripheral T cell-associated cytokines （interleukin-2, interferon-y） and hippocampal microglia-related cyto- kines （interleukin-113, tumor necrosis factor-a） correlated with the number of regenerated neural progenitor cells in the hippocampus. These results indicate that T cells promote hippocampal neurogenesis in Alzheimer＇s disease and T-cell immunodeficiency restricts neuronal regeneration in the hippocampus. The mechanism underlying the promotion of neuronal regeneration by T cells is mediated by an increased expression of peripheral T cells and central microglial cytokines in Alzheimer＇s disease mice. Our findings provide an experimental basis for understanding the role of T cells in Alzheimer＇s disease.
