microRNA-mRNA expression profiles in the skeletal muscle of myotonic dystrophy type 1

Myotonic dystrophy type 1 (DM1) is the most common muscular dystrophy in adults, yet there are currently no disease-modifying treatments. Disrupted miRNA expressions may lead to dysregulation of target mRNAs and dysfunction involved in DM1 pathogenic mechanism. We used microarray platforms to examine the miRNA/mRNA expression profiles in skeletal muscle biopsies derived from DM1 patients and matched controls. Bioinformatics analysis and dual-luciferase reporter assay were conducted to provide insight into miRNA-mRNA regulatory networks altered in DM1. Twenty-three differentially expressed miRNAs and 135 differentially expressed genes were identified. qPCR confirmed that miR-3201, myogenic factor 5 (MYF5), myogenic differentiation 1 (MYOD1), CUGBP, Elav-like family member 1 (CELF1), and CELF2 were significantly up-regulated, while miR-196a, miR-200c, and miR-146a were significantly down-regulated. Enriched functions and pathways such as multicellular organismal development, RNA splicing, cell differentiation, and spliceosome are relevant to DM1. The miRNA-mRNA interaction network revealed that miR-182, miR-30c-2, and miR-200c were the critical nodes that potentially interacted with hub genes. Luciferase reporter assay confirmed the direct interaction between miR-196a and CELF2. Those results implied that the observed miRNA/mRNA dysregulation could contribute to specific functions and pathways related to DM1 pathogenesis, highlighting the dysfunction of miR-196a and CELF2.

1型强直性肌营养不良（Myotonic dystrophy type 1, DM1）是成人最常见的肌营养不良症，但目前尚无疾病修饰治疗手段。紊乱的微小RNA（microRNA, miRNA）表达可导致靶mRNA表达失调，并参与DM1的致病机制异常。本研究通过微阵列（microarray）平台，检测了DM1患者及匹配对照的骨骼肌活检组织中的miRNA与mRNA表达谱。随后开展生物信息学分析与双荧光素酶报告基因实验，以探究DM1中发生改变的miRNA-mRNA调控网络。研究共鉴定出23个差异表达miRNA以及135个差异表达基因。实时定量聚合酶链反应（qPCR）验证结果显示，miR-3201、肌分化因子5（myogenic factor 5, MYF5）、肌分化因子1（myogenic differentiation 1, MYOD1）、CUGBP Elav样家族成员1（CUGBP, Elav-like family member 1, CELF1）及CELF2均显著上调，而miR-196a、miR-200c与miR-146a则显著下调。富集分析得到的功能与通路，如多细胞生物体发育、RNA剪接、细胞分化以及剪接体（spliceosome），均与DM1密切相关。miRNA-mRNA互作网络分析显示，miR-182、miR-30c-2及miR-200c是与核心基因存在潜在互作的关键节点。双荧光素酶报告基因实验证实，miR-196a与CELF2之间存在直接互作。上述结果表明，本研究观测到的miRNA与mRNA表达失调，可能参与DM1发病相关的特定功能与通路过程，同时凸显了miR-196a与CELF2的功能异常。