Role of CCN5 in heart failure related arrhythmias

项目摘要 老年和/或高血压患者的心力衰竭是一种主要的公共卫生流行病， 心源性猝死纤维化是这些患者的一个标志性特征，其显著有助于 胚胎发生用于对抗心力衰竭患者心律失常的现有疗法不足以治疗心力衰竭。 很大程度上是因为它们不能逆转先前存在的纤维化。基质细胞蛋白CCN 5介导疾病 通过引发针对压力超负荷诱导的应激的适应性心脏反应来消退。而 内源性CCN 5发挥有效的抗纤维化功效，我们发现慢性AAV 9介导的过表达 (OE)CCN 5在具有增加的后负荷（HF/iAL）的晚期心力衰竭模型中的作用， 衰老和/或高血压不能恢复传导或防止心律失常。此外，我们的初步 数据表明，AAV 9介导的CCN 5 OE导致不利的电重构， 慢性压力超负荷模型中的结构重塑。最后，我们发现AAV 9介导的CCN 5 在结构正常（无纤维化）的心脏中，OE引起显著的传导减慢， 膜兴奋性表明CCN 5对细胞间偶联的迄今未被认识的抑制作用 这可能会干扰其在晚期心力衰竭情况下的有益疗效。我们的核心假设是 通过CCN 5抑制纤维化的潜在抗肿瘤功效受到有害的 （纤维化非依赖性）电生理效应。我们目前的研究是专门定义纤维化的- CCN 5的依赖性和独立性，并在治疗上利用这一知识。我们的目标是 通过快速、局部和局部的方法， 使用化学修饰的RNA基因递送方法的瞬时递送，而不是慢性全局递送。 转导总的来说，该项目的完成将导致更好地了解纤维化的作用， 并指导基于机制的方法的发展，以对抗心律失常， 目前治疗选择非常有限的晚期心力衰竭患者。这些研究可能 进一步建立了一种新的机制，通过这种机制，在健康和疾病中调节细胞与细胞的偶联。研究 这项高风险的R21提案解决了目前阻碍潜在的强力抗纤维化的关键障碍 治疗向前推进。

Project Summary Heart failure in elderly and/or hypertensive patients is a major public health epidemic that predisposes to sudden cardiac death. Fibrosis is a hallmark feature of these patients that contributes significantly to arrhythmogenesis. Existing therapies for combatting arrhythmias in heart failure patients are inadequate in large part because they fail to reverse preexisting fibrosis. The matricellular protein CCN5 mediates disease regression by eliciting an adaptive cardiac response against pressure overload induced stress. While endogenous CCN5 exerts a potent anti-fibrosis efficacy, we found that chronic AAV9-mediated overexpression (OE) of CCN5 in models of advanced heart failure with increased afterload (HF/iAL) that mimic the effects of aging and/or hypertension failed to restore conduction or prevent arrhythmias. Furthermore, our preliminary data demonstrate that AAV9-mediated CCN5 OE causes adverse electrical remodeling that precedes structural remodeling in a chronic model of pressure overload. Finally, we found that AAV9-mediated CCN5 OE in structurally normal (fibrosis-free) hearts caused significant conduction slowing with no change in membrane excitability suggesting a hitherto unrecognized inhibitory effect of CCN5 on inter-cellular coupling that may interfere with its beneficial efficacy in the setting of advanced heart failure. Our central hypothesis is that the potential anti-arrhythmic efficacy of suppressing fibrosis through CCN5 is hampered by detrimental (fibrosis-independent) electrophysiological effects. Our current studies are tailored to define the fibrosis- dependent and independent properties of CCN5 and to harness this knowledge therapeutically. We aim to retain the beneficial and avoid the detrimental (fibrosis-independent) effects of CCN5 through rapid, local, and transient delivery using a chemically modified RNA gene delivery approach as opposed to chronic global transduction. Overall, completion of this project will lead to improved understanding of the role of fibrosis in arrhythmogenesis and guide the development of mechanism-based approaches for combatting arrhythmias in patients with advanced heart failure who currently have very limited therapeutic options. These studies may further establish a novel mechanism by which cell-to-cell coupling is regulated in health and disease. Studies in this high-risk R21 proposal address critical barriers that currently obstruct a potentially power anti-fibrosis therapy from advancing forward.