Feng Xuedan, Hou Huiqing, Zou Yueli, Guo Li
Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, China.
Bosn J Basic Med Sci. 2017 May 20;17(2):95-103. doi: 10.17305/bjbms.2017.1696.
Neurodegeneration, along with inflammatory demyelination, is an important component of multiple sclerosis (MS) pathogenesis. Autophagy is known to play a pivotal role in neuronal homeostasis and is implicated in several neurodegenerative disorders. However, whether autophagy is involved in the mechanisms of neuronal damage during MS remains to be investigated. Experimental autoimmune encephalomyelitis (EAE), an in vivo model of MS, was induced in female C57BL/6 mice by immunization with myelin oligodendrocyte glycoprotein p35-55. After that, autophagic flux in the spinal cord of mice was evaluated by detection of LC3-II and Beclin1 protein expressions. EAE mice were then administered with rapamycin and 3-methyladenine (3-MA) for 10 days. Afterward, the changes in LC3-II, Beclin1, and p62 expression, number of infiltrated inflammatory cells, demyelinated lesion area, and neuronal damage, as well as clinical scores, were assessed. Further, apoptotic cell rate and apoptosis-related protein expressions were monitored. We observed an impaired autophagic flux and increased neuronal damage in the spinal cords of EAE mice. We also found that rapamycin, an autophagy inducer, mitigated EAE-induced autophagy decrease, inflammation, demyelination and neuronal injury, as well as the abnormal clinical score. In addition, rapamycin suppressed cell apoptosis, and decreased Bax/Bcl-2 ratio and cleaved caspase-3 expression. Conversely, the effect of autophagy inhibitor 3-MA on EAE mice resulted in completely opposite results. These results indicated that autophagy deficiency, at least in part, contributed to EAE-induced neuronal injury and that pharmacological modulation of autophagy might be a therapeutic strategy for MS.
神经退行性变与炎性脱髓鞘一样，是多发性硬化症（MS）发病机制的重要组成部分。已知自噬在神经元稳态中起关键作用，并与多种神经退行性疾病有关。然而，自噬是否参与MS期间神经元损伤的机制仍有待研究。通过用髓鞘少突胶质细胞糖蛋白p35-55免疫雌性C57BL/6小鼠，诱导实验性自身免疫性脑脊髓炎（EAE），这是一种MS的体内模型。之后，通过检测LC3-II和Beclin1蛋白表达来评估小鼠脊髓中的自噬通量。然后给EAE小鼠施用雷帕霉素和3-甲基腺嘌呤（3-MA）10天。之后，评估LC3-II、Beclin1和p62表达的变化、浸润炎性细胞的数量、脱髓鞘病变面积和神经元损伤以及临床评分。此外，监测凋亡细胞率和凋亡相关蛋白表达。我们观察到EAE小鼠脊髓中的自噬通量受损且神经元损伤增加。我们还发现，自噬诱导剂雷帕霉素减轻了EAE诱导的自噬减少、炎症、脱髓鞘和神经元损伤以及异常的临床评分。此外，雷帕霉素抑制细胞凋亡，并降低Bax/Bcl-2比率和裂解的caspase-3表达。相反，自噬抑制剂3-MA对EAE小鼠的作用产生了完全相反 的结果。这些结果表明，自噬缺陷至少部分导致了EAE诱导的神经元损伤，并且自噬的药理学调节可能是MS的一种治疗策略。
