Effects of astrocytes on the proliferation of neural stem cells in the hippocampal microenvironment of old and young adults / 解剖学报

Objective To investigate the effect and mechanism of astrocytes on the proliferation of neural stem cells (NSCs) in adult and juvenile hippocampus microenvironment. Methods Hippocampal astrocytes were isolated and cultured from 5 female SD rats at day 1 and week 30 postnatal, respectively; Embryonic hippocampus NSCs was isolated and cultured from 1 SD rat at day 15 of gestation; Conditioned astrocyte culture medium(CM) was collected for NSCs culture; Flow cytometry and CCK-8 were used to detect the proliferation of NSCs cultured in CM. Colony stimulating factor 1 (CSF-1) with differential expression was screened by mass spectrometry after cultured astrocyte CM. Western blotting and ELISA were used to verify the result of mass spectrometry. Immunofluorescence, flow cytometry and CCK-8 were used to detect the proliferation of NSCs treated with different concentrations of CSF-1 recombinant protein (20 μg/ L, 100 μg/ L, 1 mg/ L and 5 mg/ L). Results Compared with the adult group, the CM of hippocampal astrocytes in the young group could promote the proliferation of NSCs(P<0. 01); Compared with the conditioned medium of hippocampal astrocytes in the juvenile group, the expression of CSF-1 in the hippocampus of the elder group was significantly up-regulated(P<0. 01); At 20 μg/ L, CSF-1 promoted the proliferation of NSCs(P<0. 01), and 5 mg/ L CSF-1 inhibited significantly the proliferation of NSCs(P<0. 01). Conclusion The secretion of CSF-1 by astrocytes in hippocampal microenvironment can regulate the proliferation of NSCs with the development of the times.

Expression and role of Huntingtin-associated protein 1 during valproate induced neural stem cells differentiation / 解剖学报

Objective To investigate the expression and role of Huntingtin-associated protein-1 (HAP-1) in the process of valproate acid (VP A) inducing neural stem cells (NSCs) into neurons. Methods The hippocampus NSCs of SD rats were isolated and cultured, Real-time PCR and Western blotting were used to detect HAP-1 mRNA and protein expression at day 0, day 1, day 3 and day 5 during the induction of VPA on NSCs differentiation into neurons ; Real-time PCR was used to detect the expression level of HAP-1 mRNA in multiple tissues of adult SD rats, as well as NSCs, neurons and astrocytes. After applying small interfering RNA technology to down-regulate the expression of HAP-1 mRNA in NSCs, Real-time PCR was used to detect the mRNA expression levels of neuron-specific molecules stathmin-2 ( Stmn-2), neuronal differentiation-1 (Neurod-1), microtubule-associated protein-2 (Map-2) and synapsin-1 (Syn-1), and Western blotting was used to detect the protein expression levels of neuron-specific marker β-tubulin III (Tuj-1). Immunofluorescence was used to detect the proportion of NSCs differentiated into Tuj-1 positive neurons, and to observe the development of neurons. Results At day 1 and day 3 after VPA treatment, the expression of HAP-1 mRNA and protein in the VPA group was significantly up-regulated; HAP-1 mRNA was predominantly expressed in the hippocampus, and its expression was higher in neurons, followed by NSCs, and minimally in astrocytes. After down-regulating HAP-1 with small interference technology, the proportion of NSCs differentiated into Tuj-1 positive neurons reduced, and neuron development became worse. Conclusion VPA may promote the differentiation of NSCs into neurons by up-regulating HAP-1 expression.