目的 探讨莫洛尼小鼠白血病病毒前病毒插入位点1(Pim-1)基因在体外受损神经元中的表达变化，以及神经营养因子调节Pim-1表达进而促进受损神经元突起再生的相关分子基础。方法 用反式视黄酸将Neuro-2a（N-2a）细胞诱导成为神经元样N-2a（N-2a-N）细胞，用去铁胺亚磺酸盐(DFO)抑制N-2a细胞增殖，用丙烯酰胺（ACR）损伤N-2a-N细胞突起。N-2a-N细胞分为正常对照组、损伤组、睫状神经营养因子（CNTF）及神经突起素（Nrn1）组,每组4个样本。免疫荧光细胞化学法检测N-2a-N细胞表型及Pim-1蛋白表达；用Real-time PCR和Western blotting检测Pim-1在各组的表达变化。用Western blotting检测调节Pim-1活性的相关分子，细胞存活、凋亡相关分子及轴突再生相关分子的表达变化。结果 细胞免疫荧光显示，N-2a-N细胞表达神经元标志分子β Ⅲ-微管蛋白（β-Ⅲ tubulin）和neurofilament-200，并表达Pim-1。50 μmol DFO有效抑制N-2a细胞的增殖。应用 -1 mmol/L-的ACR成功建立N-2a-N细胞突起损伤模型。N-2a-N细胞损伤后，Pim-1基因表达呈现先降低后升高，再降低的趋势。与损伤组相比，CNTF组和Nrn1组最长神经突起所占比例明显增加，细胞内信号转导分子细胞外调节蛋白激酶1/2（ERK1/2）、磷酸化细胞外调节蛋白激酶1/2（p-ERK1/2）、信号转导及转录激活因子3（STAT3）、磷酸化信号转导及转录激活因子3（p-STAT3）及Pim-1表达上调，凋亡相关分子cleaved Caspase-3及Bax表达下调，抗凋亡相关分子Bcl-2表达上调，神经突起生长相关分子生长相关蛋白43（GAP-43）表达上调.结论 修复受损N-2a-N细胞需要过表达Pim-1基因。神经营养因子CNTF、Nrn1可激活受损N-2a-N细胞ERK1/2及STAT3信号通路，进而上调Pim-1及GAP-43表达，并促进细胞突起再生。
Abstract
Objective To investigate the expression changes of provirus integration site 1 for moloney murine leukemia virus（Pim-1） gene in damaged neurons in vitro and related molecular basis of neurotrophic factors regulating Pim-1 expression and promoting the neurite regeneration of damaged neurons. Methods Neuro-2a（N-2a）cells were induced into neuron-like N-2a（N-2a-N）cells by retinoic acid，the proliferation of N-2a cells was inhibited by deferoxamine mesylate(DFO), and N-2a-N cells were injured by acrylamide. The N-2a-N cells were divided into normal control group, injury group, ciliary neurotrophic factors (CNTF) group and neuritin (Nrn1) group，with four samples in each group. The phenotype of N-2a cells and the expression of Pim-1 protein in N-2a cells were detected by immunofluorescence cytochemistry, and the expression of Pim-1 in each group was detected by Real-time PCR and Western blotting. Western blotting was used to detect the expression changes of relevant molecules involving in regulating activity of Pim-1, cells survival, apoptosis and axonal regeneration. Results Cell immunofluorescence showed that N-2a-N cells had neuronal phenotype to express β-Ⅲ tubulin and neurofilament-200, and Pim-1 protein was expressed in N-2a-N cells. N-2a cell proliferation was effectively inhibited by 50 μmol/L DFO, and N-2a-N cell damage model was established by 1 mmol/L acrylamide. Pim-1 gene expression showed a tendency of first decreasing, then increasing, and then decreasing after N-2a-N cells were injured. Compared with the injury group, the proportion of the longest neurite in CNTF group and Nrn1 group increased significantly, the expressions of intracellular signal transducers extracellular regulated protein kinase 1/2 (ERK1/2), phosphorylated extracellular regulated protein kinase 1/2 (p-ERK1/2), signal transducers and activators of transcription 3(STAT3), phosphorylated signal transducers and activators of transcription 3 (p-STAT3), and Pim-1 were up-regulated, the expressions of apoptosis-related molecules cleaved Caspase-3 and Bax were down-regulated, the expression of nti-apoptosis-related molecule Bcl-2 was up-regulated, so the growth-associated protein 43 (GAP-43) protein involved neurite regeneration. Conclusion There is a need to repair damaged N-2a-N cells by overexpressing the Pim-1 gene. CNTF and Nrn1 can activate the ERK1/2 and STAT3 signaling pathways of damaged N-2a-N cells, and then up-regulate the expression of Pim-1 and GAP-43，and then promote cell neurite regeneration.
关键词
神经元样细胞 /
睫状神经营养因子 /
神经突起素 /
莫洛尼小鼠白血病病毒前病毒插入位点1 /
实时定量聚合酶链反应
Key words
Neuron-like cell /
Ciliary neurotrophic factor /
Neuritin /
Provirus integration site for Moloney murine leukemia virus /
Real-time PCR
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基金
靶向Pim-1基因过表达修复受损视神经的作用及机制
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