长链非编码RNA Gm17501调控心肌肥厚的分子机制研究

Cardiac hypertrophy is the pivotal mechanism in the pathogenesis of heart failure. Exploration of novel regulators of cardiac hypertrophy helps to improve the treatment for cardiac hypertrophy. The majority of bidirectional lncRNA/neighboring protein-coding gene pairs originated from shared bidirectional promoters and showed positively correlated expression. It raised the intriguing possibility that the pairs may share similar biological functions. However, whether bidirectional lncRNA regulate cardiac hypertrophy remains unclear. Our previous study showed that lncRNA Gm17501 is highly conserved among the lncRNAs. The expression of lncRNA Gm17501 was increased in the development of pressure overload and phenylephrine-induced cardiac hypertrophy. Knockdown of endogenous lncRNA Gm17501 significantly increased the mRNA levels of ANP and BNP which served as the biomarkers of cardiac hypertrophy. These results suggest lncRNA Gm17501 may be involved in the regulation of cardiac hypertrophy. Therefore, in the present study, cardiac conditional transgenic and knockout mice are constructed to investigate the underlying molecular mechanisms of lncRNA Gm17501 on cardiac hypertrophy with the utilizations of biological techniques such as gene silencing, lentivirus transfection, gene chip, protein mass spectrometry in vitro and in vivo. The results will reveal a new mechanism by which lncRNA Gm17501 regulates cardiac hypertrophy and will provide new therapeutic target and the related mechanisms for the treatment of cardiac hypertrophy.

心肌肥厚是多种心脏疾病发展为心力衰竭的核心环节，探索新型心肌肥厚调控因子对于心肌肥厚的治疗具有重要意义。双向长链非编码RNA（Bidirectional lncRNA）常与邻近蛋白编码基因共享部分启动子并协同表达，两者通常具有相似的生物学功能，然而其是否可调控心肌肥厚目前尚不明确。我们的前期研究表明：双向lncRNA Gm17501保守性极强，在压力过负荷及苯肾上腺素诱导的心肌肥厚过程中表达明显上调；沉默内源性lncRNA Gm17501可显著促进心肌肥厚标志物ANP及BNP的表达。上述结果提示lncRNA Gm17501可能是心肌肥厚的重要调控因子。因此，本项目拟利用基因沉默、慢病毒转染、基因芯片及蛋白质质谱等技术，并通过构建心脏条件转基因及基因敲除小鼠，从细胞及动物水平上，深入探讨lncRNA Gm17501对心肌肥厚的调控作用并阐明其分子机制，为心肌肥厚的预防和治疗提供新的理论依据。

长链非编码RNA（lncRNA）是一类不参与蛋白质编码的RNA分子，其与多种复杂的生物学过程相关。研究表明，多种lncRNA参与调控心肌肥厚及心力衰竭的发生发展过程。lncRNA Gm17501是近年新发现的lncRNA，属于双向lncRNA，其与邻近的蛋白质编码基因心力衰竭标志物CCN1共享部分启动子。本研究首先通过RACE实验确定lncRNA Gm17501在大鼠基因组中的全长序列，并证实其在心肌细胞中主要分布于细胞质。在压力过负荷诱导的小鼠心肌肥厚和苯肾上腺素诱导的心肌细胞肥厚模型中，lncRNA Gm17501有显著的表达改变；在心力衰竭患者的心脏组织中，lncRNA Gm17501表达较非心衰患者显著下调，上述结果均提示lncRNA Gm17501参与心肌肥厚的调控。本研究进一步发现，lncRNA Gm17501沉默可显著促进苯肾上腺素诱导的心肌细胞肥厚，提示其可抑制心肌肥厚的进展。在机制研究中，课题组通过对心肌肥厚模型中lncRNA Gm17501沉默的心肌细胞的转录组测序分析，发现lncRNA Gm17501可能通过调控钙信号通路发挥抑制心肌肥厚的作用。因此，本研究证明了lncRNA Gm17501对心肌细胞肥厚具有保护作用，且该调控过程可能与钙信号通路有关，为心肌肥厚和心力衰竭的预防和治疗提供理论依据和治疗靶点。