Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK.
Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK.
Stem Cell Reports. 2020 May 12;14(5):892-908. doi: 10.1016/j.stemcr.2020.03.023. Epub 2020 Apr 23.
TDP-43 dysfunction is common to 97% of amyotrophic lateral sclerosis (ALS) cases, including those with mutations in C9orf72. To investigate how C9ORF72 mutations drive cellular pathology in ALS and to identify convergent mechanisms between C9ORF72 and TARDBP mutations, we analyzed motor neurons (MNs) derived from induced pluripotent stem cells (iPSCs) from patients with ALS. C9ORF72 iPSC-MNs have higher Ca release after depolarization, delayed recovery to baseline after glutamate stimulation, and lower levels of calbindin compared with CRISPR/Cas9 genome-edited controls. TARDBP iPS-derived MNs show high glutamate-induced Ca release. We identify here, by RNA sequencing, that both C9ORF72 and TARDBP iPSC-MNs have upregulation of Ca-permeable AMPA and NMDA subunits and impairment of mitochondrial Ca buffering due to an imbalance of MICU1 and MICU2 on the mitochondrial Ca uniporter, indicating that impaired mitochondrial Ca uptake contributes to glutamate excitotoxicity and is a shared feature of MNs with C9ORF72 or TARDBP mutations.
TDP-43 功能障碍常见于 97%的肌萎缩侧索硬化症 (ALS)病例，包括 C9orf72 突变的病例。为了研究 C9ORF72 突变如何导致 ALS 中的细胞病理学，并确定 C9ORF72 和 TARDBP 突变之间的趋同机制，我们分析了来自 ALS 患者诱导多能干细胞 (iPSC) 的运动神经元 (MNs)。与 CRISPR/Cas9 基因组编辑对照相比，C9ORF72 iPSC-MN 在去极化后具有更高的 Ca 释放、谷氨酸刺激后基线恢复延迟以及钙结合蛋白水平降低。TARDBP iPSC 衍生的 MN 显示出高谷氨酸诱导的 Ca 释放。我们通过 RNA 测序在这里确定，C9ORF72 和 TARDBP iPSC-MN 均上调 Ca 通透性 AMPA 和 NMDA 亚基，并且由于线粒体 Ca 单向转运体上 MICU1 和 MICU2 的失衡，导致线粒体 Ca 缓冲受损，表明受损的线粒体 Ca 摄取导致谷氨酸兴奋性毒性，并且是具有 C9ORF72 或 TARDBP 突变的 MN 的共同特征。
