应用iPSC探讨肌萎缩侧索硬化中C9orf72突变诱导神经元自噬损伤及胶质细胞的加强效应

C9orf72（C9）突变与肌萎缩侧索硬化（ALS）相关，但其致病机制尚不明确。研究报道C9突变引起C9ORF72蛋白低表达与运动神经元（MN）自噬相关，但结论不一致；同时报道，C9突变还可通过星形胶质细胞（AS）神经毒性参与MN损伤。前期工作表明，C9突变AS的培养液降低MN生存率、改变自噬相关蛋白表达，由此推测C9突变引起的MN自噬损伤不足以致其死亡，而同时所诱导的AS神经毒性可以加剧自噬障碍共同导致MN退行病变。本研究收集C9突变ALS病人的成纤维细胞，重编程为诱导多能干细胞（iPSC），进而分化为MN与AS，研究C9突变通过调节C9ORF72表达及其与复合物结合影响MN自噬的机制，探讨C9突变诱发AS活化释放细胞因子加强自噬损伤的作用与物质基础。以C9突变病人的iPSC为研究模型，更贴近临床地揭示C9突变相关神经退化的新机制，为相关疾病的预防治疗与药物筛选奠定理论基础，提供新靶点。

Mutation of C9orf72 (C9) may lead to amyotrophic lateral sclerosis (ALS), but the pathogenic mechanism is not yet clear. It has been reported that C9 mutation decreased the expression of C9ORF72 protein, which is associated with the autophagy of motor neuron (MN) , but the the existing experiments conclusions are inconsistent. At the same time, it is reported that C9 mutation can also participate in MN injury through neurotoxicity induced by astrocyte (AS). Previous work showed that the medium of C9-mutant AS reduced the survival rate of MN and altered the expression of autophagy-related proteins. Basing on these results, we speculate that the autophagic damage of MN caused by C9 mutation is too weak to cause MN death. Meanwhile, the neurotoxicity induced by AS may aggravate the autophagic disorder of MN. Thus, both of them will lead to the MN pathological degeneration together. In this study, fibroblasts from patients with C9-mutated ALS were recruited and reprogrammed into induced pluripotent stem cells (iPSCs), and then iPSC were differentiated into MN and AS. The mechanism of C9 mutations affecting MN autophagy by regulating the expression of C9ORF72 and its complexes will be investigated. And the effects and the substance basis of worsening autophagic damage of MN by C9 mutation-induced AS activation and cytokines release will be explored. Taking C9 mutation patients-derived iPSCs as research models, we can reveal the new C9 mutation-related neurodegeneration mechanism close to clinical therapy, so as to lay a theoretical foundation for the prevention and treatment of related diseases and drug screening, and provide a new possible treatment target.