Transcriptome analysis of the TA muscles from WT and Dmd Exon 51 Knockout mice

Duchenne muscular dystrophy (DMD) is a fatal muscle disorder characterized by cycles of degeneration and regeneration of multinucleated myofibers and pathological activation of a variety of other associated cell types. Here, we describe the creation of a new mouse model of DMD caused by deletion of exon 51 of the dystrophin gene, which represents a prevalent mutation in humans. To understand the transcriptional abnormalities and heterogeneity associated with the nuclei of myofibers, as well as other mononucleated cell types that contribute to DMD disease pathogenesis, we performed single nucleus transcriptomics of skeletal muscle of mice with exon 51 deletion. Our results reveal distinctive and previously unrecognized myonuclear subtypes within dystrophic myofibers and uncover degenerative and regenerative transcriptional pathways underlying DMD pathogenesis. Our findings provide new insights into the molecular underpinnings of DMD, controlled by the transcriptional activity of different types of muscle and nonmuscle nuclei. RNA was isolated from TA muscles of 1 month old WT or DMD deltaEx51 mice. Stranded mRNA-seq was performed to profile gene expression changes upon exon 51 deletion.杜氏肌营养不良症（Duchenne muscular dystrophy, DMD）是一类致命性肌肉疾病，其病理特征为多核肌纤维反复发生变性与再生，同时伴随多种相关细胞类型的病理性激活。本研究构建了一种新型DMD小鼠模型，该模型由抗肌萎缩蛋白基因外显子51缺失诱导产生，而此类突变在人类患者中属于常见突变类型。为解析肌纤维细胞核相关的转录异常与异质性，以及参与DMD发病机制的其他单核细胞类群，本研究对携带外显子51缺失的小鼠骨骼肌开展了单细胞核转录组测序（single nucleus transcriptomics）。研究结果揭示了营养不良性肌纤维内此前未被报道的独特肌核亚型，并阐明了DMD发病机制背后的变性与再生相关转录通路。本研究结果为DMD的分子机制提供了全新见解，而该疾病的进程受不同类型肌细胞核与非肌细胞核的转录活性调控。本研究从1月龄野生型（wild type, WT）或DMD ΔEx51小鼠的胫前肌（TA）中提取总RNA，并通过链特异性mRNA测序（Stranded mRNA-seq）分析外显子51缺失后的基因表达变化情况。