Mechano-regulated RNA binding protein hnRNPC contributes to RNA homeostasis in heart failure [RNA-Seq]

Cardiac pathologies are characterized by intense remodeling of the extracellular matrix (ECM) that eventually leads to heart failure. Cardiomyocytes respond to the ensuing biomechanical stress by re-expressing fetal contractile proteins via transcriptional and post-transcriptional processes, like alternative splicing (AS). Here, we demonstrate that the heterogeneous nuclear ribonucleoprotein C (hnRNPC) is upregulated and relocates to the sarcomeric Z-disk upon ECM pathological remodeling. At this site, the protein participates to the localized translation of mRNAs encoding sarcomeric proteins. Alterations in hnRNPC expression and localization can be mechanically determined and affect the AS of numerous mRNAs involved in mechanotransduction and cardiovascular diseases. We thus propose that cardiac ECM remodeling serves as a switch in RNA metabolism by directly impacting an associated regulatory protein of the spliceosome apparatus. These findings offer new insights on the mechanism of mRNAs homeostasis mechanoregulation in disease conditions. Overall design: RNA sequencing of : NHDFs transfected with a stealth siRNA negative control low GC and NHDFs transfected with hnRNPC1/C2 siRNA HSS179304 (KD1) and hnRNPC1/C2 siRNA HSS179305

心脏疾病以细胞外基质（extracellular matrix, ECM）的剧烈重塑为核心特征，最终可进展为心力衰竭。心肌细胞可对由此产生的生物机械应激产生应答：通过转录及转录后调控过程（如可变剪接（alternative splicing, AS））重表达胎儿型收缩蛋白。
本研究证实，在ECM病理性重塑过程中，异质性细胞核核糖核蛋白C（heterogeneous nuclear ribonucleoprotein C, hnRNPC）的表达水平显著上调，并易位至肌节Z盘。该蛋白在此位点参与编码肌节蛋白的信使RNA（mRNA）的局部翻译过程。
hnRNPC的表达与定位异常可通过机械手段被检测到，并会影响众多参与机械转导及心血管疾病的mRNA的可变剪接事件。据此我们提出，心脏ECM重塑可通过直接作用于剪接体复合物的相关调控蛋白，成为RNA代谢的关键调控开关。本研究结果为疾病状态下mRNA稳态的机械调控机制提供了全新的研究视角。
实验设计：对以下样本进行RNA测序：转染低GC含量隐形小干扰RNA（stealth siRNA）阴性对照的正常人皮肤成纤维细胞（Normal Human Dermal Fibroblasts, NHDFs），以及分别转染hnRNPC1/C2小干扰RNA（small interfering RNA, siRNA）HSS179304（KD1）、hnRNPC1/C2小干扰RNA（siRNA）HSS179305的NHDFs。