Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, 606-8507, Japan.
Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, 606-8507, Japan.
Sci Rep. 2017 Oct 18;7(1):13473. doi: 10.1038/s41598-017-14063-y.
Pompe disease is caused by an inborn defect of lysosomal acid α-glucosidase (GAA) and is characterized by lysosomal glycogen accumulation primarily in the skeletal muscle and heart. Patients with the severe type of the disease, infantile-onset Pompe disease (IOPD), show generalized muscle weakness and heart failure in early infancy. They cannot survive over two years. Enzyme replacement therapy with recombinant human GAA (rhGAA) improves the survival rate, but its effect on skeletal muscle is insufficient compared to other organs. Moreover, the patho-mechanism of skeletal muscle damage in IOPD is still unclear. Here we generated induced pluripotent stem cells (iPSCs) from patients with IOPD and differentiated them into myocytes. Differentiated myocytes showed lysosomal glycogen accumulation, which was dose-dependently rescued by rhGAA. We further demonstrated that mammalian/mechanistic target of rapamycin complex 1 (mTORC1) activity was impaired in IOPD iPSC-derived myocytes. Comprehensive metabolomic and transcriptomic analyses suggested the disturbance of mTORC1-related signaling, including deteriorated energy status and suppressed mitochondrial oxidative function. In summary, we successfully established an in vitro skeletal muscle model of IOPD using patient-specific iPSCs. Disturbed mTORC1 signaling may contribute to the pathogenesis of skeletal muscle damage in IOPD, and may be a potential therapeutic target for Pompe disease.
庞贝病是由溶酶体酸性α-葡萄糖苷酶（GAA）的先天缺陷引起的，其特征是溶酶体糖原主要在骨骼肌和心脏中积累。严重型患者，婴儿起病型庞贝病（IOPD），在婴儿早期表现为全身肌肉无力和心力衰竭。他们无法存活超过两年。重组人 GAA（rhGAA）的酶替代疗法提高了生存率，但与其他器官相比，其对骨骼肌的作用仍不充分。此外，IOPD 中骨骼肌损伤的病理机制仍不清楚。在这里，我们从 IOPD 患者中生成诱导多能干细胞（iPSC）并将其分化为肌细胞。分化的肌细胞表现出溶酶体糖原积累，rhGAA 可呈剂量依赖性地挽救。我们进一步证明，IOPD iPSC 衍生的肌细胞中哺乳动物/雷帕霉素靶蛋白复合物 1（mTORC1）活性受损。综合代谢组学和转录组学分析表明，mTORC1 相关信号通路受到干扰，包括能量状态恶化和线粒体氧化功能受抑制。总之，我们使用患者特异性 iPSC 成功建立了 IOPD 的体外骨骼肌模型。受损的 mTORC1 信号可能有助于 IOPD 中骨骼肌损伤的发病机制，并且可能是庞贝病的潜在治疗靶点。
