ALS转基因小鼠脊髓中miRNA-132表达减少BDNF表达增加

Decrease in expression of miRNA-132 and increase in expression of BDNF in the spinal cord of ALS transgenic mice

目的研究miRNA-132和脑源性神经营养因子(brain derived neurotrophic factor,BDNF)在肌萎缩侧索硬化症(amyotrophic lateral sclerosis,ALS)转基因小鼠脊髓中的表达变化,探讨miRNA-132、BDNF在ALS发病中的作用。方法取SOD1-G93A ALS转基因鼠发病早期(95d)、中期(108d)和晚期(122d)脊髓组织,应用qRT-PCR及原位杂交(hybridization in situ, ISH)技术检测miRNA-132的表达及定位,应用qRT-PCR及Western blot技术检测BDNF在mRNA及蛋白水平变化,免疫荧光技术检测BDNF在脊髓中的表达及分布,以同窝野生型鼠作为对照。结果与野生型鼠比较,miRNA-132在ALS转基因鼠脊髓组织表达下降,miRNA-132阳性信号主要定位脊髓前角细胞胞体;在ALS转基因鼠脊髓组织BDNF mRNA及蛋白水平均增高,BDNF免疫阳性细胞主要表达于脊髓前角神经元,表达信号明显增强。结论 miRNA-132、BDNF可能在ALS发病过程中发挥了重要作用。

Objective To investigate the expression of miRNA-132 and brain derived neurotrophic factor (BDNF) in the spinal cord of amyotrophic lateral sclerosis (ALS) transgenic mice, and to explore the role of miRNA-132 and BDNF in the pathogenesis of ALS. Methods The spinal cord tissues of SOD1-G93A ALS transgenic mice were detected at early stage (95d), middle stage (108d) and late stage (122d). The expression and localization of miRNA-132 were detected by qRT-PCR and in situ hybridization (ISH). The changes of BDNF in mRNA and protein levels were detected by qRT-PCR and Western-blot. In addition, the expression of BDNF in the anterior horn of spinal cord and its co-localization with neurons were detected by immunofluorescence technique, compared with the wild-type mice from the same cages as controls. Results Compared with wild-type mice, miRNA-132 expression decreased in spinal cord tissue of ALS transgenic mice and its positive signal mainly localized the anterior horn cells of spinal cord. While the mRNA and protein levels of BDNF increased in spinal cord tissue. BDNF positive cells were mainly located in the anterior horn of spinal cord and its positive expression signal was significantly enhanced. The anterior horn is co-expressed with β-tubulin III labeled neurons. Conclusion miRNA-132 and BDNF may play an important role in the pathogenesis of ALS.