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 Ca²⁺ 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 Ca²⁺ release. We identify here, by RNA sequencing, that both C9ORF72 and TARDBP iPSC-MNs have upregulation of Ca²⁺-permeable AMPA and NMDA subunits and impairment of mitochondrial Ca²⁺ buffering due to an imbalance of MICU1 and MICU2 on the mitochondrial Ca²⁺ uniporter, indicating that impaired mitochondrial Ca²⁺ uptake contributes to glutamate excitotoxicity and is a shared feature of MNs with C9ORF72 or TARDBP mutations.

TDP-43 功能障碍在 97% 的肌萎缩侧索硬化症 (ALS) 病例中很常见，包括C9orf72突变的病例。为了研究C9ORF72突变如何驱动 ALS 的细胞病理学并确定C9ORF72和TARDBP突变之间的趋同机制，我们分析了源自 ALS 患者诱导多能干细胞 (iPSC) 的运动神经元 (MN)。与 CRISPR/Cas9 基因组编辑对照相比， C9ORF72 iPSC-MN 在去极化后具有较高的 Ca ²⁺释放，在谷氨酸刺激后延迟恢复到基线，并且钙结合蛋白水平较低。 TARDBP iPS 衍生的 MN 显示出高谷氨酸诱导的 Ca ²⁺释放。我们通过 RNA 测序在此确定， C9ORF72和TARDBP iPSC-MN 均上调 Ca ²⁺可渗透的 AMPA 和 NMDA 亚基，并且由于线粒体 Ca ²⁺上的 MICU1 和 MICU2 不平衡而损害线粒体 Ca ²⁺缓冲单转运蛋白，表明线粒体 Ca ²⁺摄取受损会导致谷氨酸兴奋毒性，并且是具有C9ORF72或TARDBP突变的 MN 的共同特征。