ICFO-The Institute of Photonic Sciences, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Spain.
ALBA Synchrotron Light Source, 08290 Cerdanyola del Vallès, Spain.
Int J Mol Sci. 2022 Jul 11;23(14):7651. doi: 10.3390/ijms23147651.
Collagen VI-related disorders (COL6-RD) represent a severe form of congenital disease for which there is no treatment. Dominant-negative pathogenic variants in the genes encoding α chains of collagen VI are the main cause of COL6-RD. Here we report that patient-derived fibroblasts carrying a common single nucleotide variant mutation are unable to build the extracellular collagen VI network. This correlates with the intracellular accumulation of endosomes and lysosomes triggered by the increased phosphorylation of the collagen VI receptor CMG2. Notably, using a CRISPR-Cas9 gene-editing tool to silence the dominant-negative mutation in patients' cells, we rescued the normal extracellular collagen VI network, CMG2 phosphorylation levels, and the accumulation of endosomes and lysosomes. Our findings reveal an unanticipated role of CMG2 in regulating endosomal and lysosomal homeostasis and suggest that mutated collagen VI dysregulates the intracellular environment in fibroblasts in collagen VI-related muscular dystrophy.
胶原 VI 相关疾病（COL6-RD）是一种严重的先天性疾病，目前尚无治疗方法。编码胶原 VI α 链的基因中的显性负致病性变异是 COL6-RD 的主要原因。在这里，我们报告说，携带常见单核苷酸变异突变的患者来源成纤维细胞无法构建细胞外胶原 VI 网络。这与胶原 VI 受体 CMG2 磷酸化增加引发的内涵体和溶酶体在细胞内的积累有关。值得注意的是，使用 CRISPR-Cas9 基因编辑工具沉默患者细胞中的显性负突变，我们挽救了正常的细胞外胶原 VI 网络、CMG2 磷酸化水平以及内涵体和溶酶体的积累。我们的研究结果揭示了 CMG2 在调节内涵体和溶酶体动态平衡中的意外作用，并表明突变胶原 VI 使纤维母细胞中的细胞内环境紊乱，导致与胶原 VI 相关的肌肉营养不良。
