环状RNA circITCH调控Wnt/β-catenin/ Cx43信号轴在心肌缺血室性心律失常中作用及分子机制研究

There is still lack of exploration about the role of circRNA in the occurrence of arrhythmia, which is very important in cardiovascular diseases. Our results showed that circRNA circITCH plays a key role in myocardial ischemic ventricular arrhythmia. Our preliminary results demonstrated that circITCH significantly increased in ischemic myocardium, and the expression of connexin Cx43 significantly reduced, suggesting that circITCH may play an important role in the regulation of arrhythmia. However, the mechanism is unknown. The specific mechanism still needs further identification. Therefore, we hypothesized that circRNA circITCH may facilitate myocardial ischemic ventricular arrhythmia by regulating connexin 43 through Wnt/β-catinin signaling pathway. To assess this hypothesis, we adopted rat myocardial cell and ventricular arrhythmia models to explore the function of circRNA circITCH in arrhythmia. This study investigated the mechanism of ventricular arrhythmia from the aspect of circRNA, which may provide new orientation for the prevention and treatment of myocardial ischemic ventricular arrhythmia.

环状RNA在心血管疾病中发挥重要作用，然而其与心律失常的关系和机制不清。我们的预实验结果提示circITCH在缺血心肌中表达明显升高，然而缝隙连接蛋白Cx43表达明显降低，提示circITCH在调控心律失常中可能起重要作用，但机制未明。为此，我们提出假说：环状RNA circITCH可能通过Wnt/β-catenin信号通路调控缝隙连接蛋白Cx43，促进室性心律失常的发生。为了验证这一假说，我们将通过心肌特异性circITCH敲除大鼠心肌缺血室性心律失常模型和H9C2细胞缺氧模型，从分子、细胞、组织等体内外多方面探讨环状RNA circITCH在室性心律失常发生中的重要作用，明确环状RNA circITCH通过Wnt/β-catenin/Cx43信号通路对细胞缝隙连接及心律失常的调控机制。本研究将从环状RNA circITCH这个新视角为揭示心肌缺血室性心律失常的发生机制提供新的思路。

环状RNA在心血管疾病中发挥重要作用，然而其与心梗后再灌注损伤的关系和机制不清。我们通过高通量筛选了差异表达的circRNA01724，qPCR验证其在心肌缺血室性心律失常模型中低表达。为验证其功能，通过大鼠心肌细胞缺氧造模，转染circRNA01724过表达慢病毒(Lv-circ01724)，发现Lv-circ01724具有促凋亡作用，同时显著下调Cx43,ZO-1, α-catenin的表达，通过双荧光素酶实验证明circRNA01724与miR-323-5p存在相互作用，认为circRNA01724对缺氧心肌细胞具有促凋亡作用，与心肌缺血室性心律失常疾病模型相关，可能是潜在的作用靶点。同时通过高通量测序法筛选了Sham和MIRI大鼠心肌组织中的差异基因，发现MIRI组中circRNA02318的表达下降，通过MIRI大鼠模型以及大鼠心肌细胞H/R建模，发现CircRNA02318通过抑制Drebrin对MIRI大鼠发挥了治疗作用，过量表达可下调H/R H9C2细胞和MIRI大鼠心脏组织中的Drebrin、Nox1、裂解caspase-3和Bax，增加p-Akt /Akt和Bcl-2的表达，而Drebrin过表达促进细胞凋亡。这种影响可被circRNA02318所废除。我们从分子、细胞、组织等体内外多方面探讨环状RNA circircRNA01724和circRNA02318在心肌梗死以及心肌缺血后室性心律失常发生中的重要作用，从环状RNA这个新视角为揭示心肌缺血后再灌注损伤的发生机制以及治疗提供新的思路。