miR-486 is an epigenetic modulator of Duchenne muscular dystrophy pathologies [RNA-seq]

Duchenne muscular dystrophy (DMD) is an X-linked progressive muscle disorder resulting in muscle weakness and cardiomyopathy. MicroRNAs have shown to play a significant role in muscle development, metabolism, and disease pathologies. We demonstrated that miR-486 expression is reduced in DMD muscles and its expression levels correlate with dystrophic disease severity. miR-486 knockout mice developed disrupted myofiber architecture, decreased myofiber size, decreased locomotor activity, increased fibrosis, and metabolic defects that were exacerbated on the dystrophic mdx5cv background. We integrated RNA-sequencing and chimeric eCLIP-sequencing data to identify direct in vivo targets of miR-486 and associated dysregulated gene signatures in skeletal muscle. Together, our studies identify miR-486 as a driver of muscle remodeling in DMD, a useful biomarker for dystrophic disease progression, and highlight chimeric eCLIP-sequencing as a useful tool to identify direct in vivo microRNA target transcripts. Whole TA muscles were isolated from male 6-month wild type (C57/Bl6) and mdx5cv (DMD mouse model on B6 strain background)杜氏肌营养不良症（Duchenne muscular dystrophy, DMD）是一种X连锁进行性肌肉疾病，可引发肌肉无力与心肌病。微小RNA（MicroRNAs）已被证实可在肌肉发育、代谢及疾病病理过程中发挥关键调控作用。本研究证实，miR-486在DMD患者的肌肉组织中表达下调，且其表达水平与营养不良性疾病的严重程度呈显著相关。miR-486敲除小鼠会出现肌纤维结构紊乱、肌纤维尺寸减小、运动能力下降、纤维化程度升高以及代谢缺陷，且在营养不良性mdx5cv小鼠背景下，上述表型会进一步加重。本研究整合了RNA测序（RNA-sequencing）与嵌合式增强交联免疫沉淀测序（chimeric eCLIP-sequencing）数据，以鉴定miR-486在骨骼肌中的直接体内靶标及相关失调基因特征。综上，本研究明确了miR-486作为DMD中肌肉重塑的调控驱动因子，可作为营养不良性疾病进展的有效生物标志物，并证实嵌合式增强交联免疫沉淀测序是鉴定体内直接微小RNA靶标转录本的实用工具。研究人员从6月龄雄性野生型（C57/Bl6）及B6遗传背景下的DMD小鼠模型mdx5cv体内分离得到完整胫前肌（TA）。