Schmitt Rebecca E, Smith Douglas Y, Cho Dong Seong, Kirkeby Lindsey A, Resch Zachary T, Liewluck Teerin, Niu Zhiyv, Milone Margherita, Doles Jason D
Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, 55905, USA.
Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
NPJ Regen Med. 2022 Sep 9;7(1):48. doi: 10.1038/s41536-022-00238-3.
Hereditary muscle diseases are disabling disorders lacking effective treatments. UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase (GNE) myopathy (GNEM) is an autosomal recessive distal myopathy with rimmed vacuoles typically manifesting in late adolescence/early adulthood. GNE encodes the rate-limiting enzyme in sialic acid biosynthesis, which is necessary for the proper function of numerous biological processes. Outside of the causative gene, very little is known about the mechanisms contributing to the development of GNE myopathy. In the present study, we aimed to address this knowledge gap by querying the underlying mechanisms of GNE myopathy using a patient-derived induced pluripotent stem-cell (iPSC) model. Control and patient-specific iPSCs were differentiated down a skeletal muscle lineage, whereby patient-derived GNEM iPSC clones were able to recapitulate key characteristics of the human pathology and further demonstrated defects in myogenic progression. Single-cell RNA sequencing time course studies revealed clear differences between control and GNEM iPSC-derived muscle precursor cells (iMPCs), while pathway studies implicated altered stress and autophagy signaling in GNEM iMPCs. Treatment of GNEM patient-derived iMPCs with an autophagy activator improved myogenic differentiation. In summary, we report an in vitro, iPSC-based model of GNE myopathy and implicate defective myogenesis as a contributing mechanism to the etiology of GNE myopathy.
遗传性肌肉疾病是缺乏有效治疗方法的致残性疾病。UDP-N-乙酰葡糖胺-2-表异构酶/N-乙酰甘露糖胺激酶（GNE）肌病（GNEM）是一种常染色体隐性远端肌病，伴有镶边空泡，通常在青春期后期/成年早期出现。GNE编码唾液酸生物合成中的限速酶，这对众多生物过程的正常功能是必需的。除了致病基因外，关于导致GNE肌病发展的机制知之甚少。在本研究中，我们旨在通过使用患者来源的诱导多能干细胞（iPSC）模型探究GNE肌病的潜在机制来填补这一知识空白。对照和患者特异性iPSC被诱导分化为骨骼肌谱系，由此患者来源的GNEM iPSC克隆能够重现人类病理学的关键特征，并进一步证明其在成肌进展方面存在缺陷。单细胞RNA测序时间进程研究揭示了对照和GNEM iPSC来源的肌肉前体细胞（iMPC）之间的明显差异，而通路研究表明GNEM iMPC中的应激和自噬信号传导发生了改变。用自噬激活剂处理GNEM患者来源的iMPC可改善成肌分化。总之，我们报告了一种基于iPSC的GNE肌病体外模型，并表明成肌缺陷是GNE肌病病因的一个促成机制。
