The influence of overexpression of NeuroD1 on transdifferentiation of spinal cord reactive astrocytes into neurons / 中国神经精神疾病杂志

Objective To investigate the effect of the overexpression of NeuroD1 on mediating transdifferentiation of spinal reactive astrocytes into neurons. Methods Spinal cord astrocytes were cultured from the SD rat, and reactive astrocytes were prepared by scratches treatment. Cells were divided into blank groups (NV group), control virus group (GFP group) and NeuroD1 virus group (NeuroD1 group). At 7 d after scratches treatment, GFP and NeuroD1 groups were infected with retroviruses carrying the GFP gene and and GFP gene plus NeuroD1 gene, respectively,whereas NV group was not infected with the virus. Twenty-four hours late, the culture medium were replaced by neuron conditioned medi?um. Cell morphology was examined at 1, 2, 3, 5, 7 and 14 d. DCX positive and NeuN positive cells were detected at 7 d and 14 d after infection by using immunofluorescence staining method, respectively. Results After replacement with the neuron conditioned medium, the nucleus was obviously plump, the cytoplasm was thin and neurites was reduced and ex?tended. Compared with the NeuroD1 group, neurites of NV group and GFP group were shorter with many branches and the nucleus was smaller. At 7 d after infection, cell morphology of NV group and GFP group gradually recovered, but cell morphology of NeuroD1 group did not. Compared with NV group and GFP group, NeuroD1 group had more DCX(9.84 ± 2.06%)and NeuN(8.25±2.78%)positive cells [F values 40.107 for DCX and 21.73 for NeuN (P<0.05)]. Conclusion The overexpression of NeuroD1 can mediate the transdifferentiation of spinal reactive astrocytes into neurons.

Characterization of nestin expression in astrocytes in the rat hippocampal CA1 region following transient forebrain ischemia / 대한해부학회지

Recent studies have suggested that nestin facilitates cellular structural remodeling in vasculature-associated cells in response to ischemic injury. The current study was designed to investigate the potential role of post-ischemic nestin expression in parenchymal astrocytes. With this aim, we characterized ischemia-induced nestin expression in the CA1 hippocampal region, an area that undergoes a delayed neuronal death, followed by a lack of neuronal generation after transient forebrain ischemia. Virtually all of the nestin-positive cells in the ischemic CA1 hippocampus were reactive astrocytes. However, induction of nestin expression did not correlate simply with astrogliosis, but rather showed characteristic time- and strata-dependent expression patterns. Nestin induction in astrocytes of the pyramidal cell layer was rapid and transient, while a long-lasting induction of nestin was observed in astrocytes located in the CA1 dendritic subfields, such as the stratum oriens and radiatum, until at least day 28 after ischemia. There was no detectable expression in the stratum lacunosum moleculare despite the evident astroglial reaction. Almost all of the nestin-positive cells also expressed a transcription factor for neural/glial progenitors, i.e., Sox-2 or Sox-9, and some cells were also positive for Ki-67. However, all of the nestin-positive astrocytes expressed the calcium-binding protein S100beta, which is known to be expressed in a distinct, post-mitotic astrocyte population. Thus, our data indicate that in the ischemic CA1 hippocampus, nestin expression was induced in astroglia that were becoming reactive, but not in a progenitor/stem cell population, suggesting that nestin may allow for the structural remodeling of these cells in response to ischemic injury.

The Expression and Significance of IGF-1 and survivin in Reactive and Neoplastic Astrocytes / 医学研究杂志

Objective To study the difference of IGF-1,Bcl-2,survivin and Ki-67 protein expression in reactive and neoplastic astrocytes and the significance of them.Methods Immunohistochemistry and tissue microarray techniques were used to determinate the expression of IGF-1,Bcl-2,survivin and Ki-67 protein in normal brain tissues, astrocytes proliferation,low-grade astrocytomas, and high-grade astrocytomas.Results The expression of IGF-1,Bcl-2,survivin and Ki-67 protein were all negative in control group.The positive expression rates of them in reactive astrocytes were 28.9%, 26.7%, 26.7% and 22.2%,respectvely; and in low-grade astrocytomas were 63.8%, 50.0%, 53.2%,70.2%; in high-grade astrocytomas were 88.9%, 79.2%, 88.1%,95.2%.IGF-1,Bcl-2,survivin and Ki-67 all had significant difference among the three experimental groups(P

Expression of mRNAs for BDNF and NT-3 in Reactive Astrocytes

OBJECTIVE: Astrocytes secrete various neurotrophic factors which act to support the survival and growth of neurons. Reactive astrocytes express an increased level of neurotrophic factors in response to central nervous system injury. We demonstrate that reactive astrocytes could express neurotrophic factors to promote neuronal rescue and generate functional recovery. METHODS: To investigate the correlation of neurotrophic factor, brain-derived neurotrophic factor(BDNF) and neurotrophin-3(NT-3) to glutamate-induced reactive gliosis, mRNA expression of BDNF and NT-3 were detected by the RT-PCR technique. RESULTS: Exposure of cultured astrocytes to L-glutamate(1, 100, 200 and 500 microM) and scraped astrocytes for 1 day resulted in significant cell damage and we observed mRNA expression of BDNF and NT-3. The maximal expression of BDNF was observed in the control, scraped and L-glutamate treated astrocytes(1 microM). The basal expression of BDNF mRNA in astrocytes treated with L-glutamate(100, 200 and 500 microM) decreased relative to that of control, scraped and L-glutamate treated astrocytes(1 microM). Reactive gliosis, treatment of control astrocytes with glutamate, showed similar pattern for NT-3 mRNA expression. In a word, the basal content of NT-3 mRNA in scrape and L-glutamate(1, 100, 200 and 500 microM) expressed similar to that of control astrocytes. CONCLUSION: This study indicates that the reactive astrocytes also expressed mRNA of BDNF and NT-3 as normal astrocytes.