Novel Mechanisms of Cardiac Function and Dysfunction

激酶在心力衰竭（HF）的发展中起着关键作用，因此，代表了一种潜在的 治疗靶点虽然心脏激酶组由数百种激酶组成，但绝大多数激酶都是由蛋白质组成的。 文献仅关注少数激酶。事实上，许多高表达的心脏激酶的功能 这些可能包括心血管疾病的潜在治疗靶点。以便识别 新的心肌激酶可能参与HF的发展，我们采用了整合的转录组， 用生物信息学方法（表达2激酶（X2 K））对对照和衰竭的心脏进行分析。事实上，在我们的筛选中， 结果，大多数鉴定的激酶在心脏生物学中的作用是众所周知的，验证了应用的 approach.有趣的是，我们还发现了一种新的激酶，同源结构域相互作用蛋白激酶2（HIPK 2）， 可能参与心脏重塑和HF的调节。事实上，没有任何文献 描述了HIPK 2在心脏中的功能。本提案的总体目标是定义HIPK 2在以下方面的作用： 心脏病理生理学作为实现这一目标的第一步，我们已经生成了小鼠模型，包括 成纤维细胞（FB）特异性HIPK 2科斯（骨膜素MCM和TCF 21 MCM）和心肌细胞（CM）特异性HIPK 2科斯 （αMHCCre和αMHCMCM）。设计了三个具体目标来严格检查HIPK 2在心脏中的作用。 生物学目的1：明确HIPK 2在心脏纤维化和重塑中的作用。我们将检验这个假设， HIPK 2通过抑制促纤维化TGF-β1/SMAD-3和p38对纤维化重塑发挥关键性破坏作用 途径。在目标2中，我们将检验CM-HIPK 2在维持基础心脏功能中是必需的这一假设。 体内平衡和所需的保护免受心脏压力。我们将利用可诱导的CM特异性cre小鼠， 仅在完全成熟的CM中删除HIPK 2，评价HIPK 2可能发挥其 心脏保护作用目的3将评估AAV 9介导的HIPK 2基因治疗对肿瘤的治疗效果。 减轻由心脏应激引起的病理。HIPK 2的表达显著降低， 在人类心脏中，我们假设心脏细胞中HIPK 2的恢复将减少并可能逆转心肌细胞中HIPK 2的表达。 心脏病AAV 9-HIPK 2将用于递送FB特异性（在骨膜蛋白启动子和TCF 21下）。 启动子）和CM特异性（肌钙蛋白-t启动子）基因表达。这些研究将直接测试 目的1和2的发现的翻译潜力。因此，所提出的研究具有重要意义， 不仅通过贡献与预防相关的信息，而且还通过提供新的机制见解， 心脏病理生理学

Kinases play a critical role in the development of heart failure (HF) and, therefore, represent a potential therapeutic target. While the cardiac kinome is comprised of several hundred kinases, the vast majority of the literature is focused on only a few kinases. Indeed, the function of numerous highly expressed cardiac kinases is unexplored; these may include potential therapeutic targets for cardiovascular diseases. In order to identify novel cardiac kinase(s) potentially involved in HF development, we employed an integrated transcriptome and bioinformatics approach (Expression2Kinases (X2K)) with control and failing hearts. Indeed, in our screening results, most of the identified kinases are well-known for their roles in cardiac biology, validating the applied approach. Intriguingly, we also identified a novel kinase, Homeodomain-Interacting Protein Kinase 2 (HIPK2), as potentially being involved in the regulation of cardiac remodeling and HF. Indeed, there is no literature describing the function of HIPK2 in the heart. The overall goal of this proposal is to define the role of HIPK2 in cardiac pathophysiology. As a first step towards this goal, we have generated mouse models including fibroblast (FB)-specific HIPK2 KOs (periostinMCM and TCF21MCM) and cardiomyocyte (CM)-specific HIPK2 KOs (αMHCCre and αMHCMCM). Three specific aims are designed to critically examine the role of HIPK2 in cardiac biology. Aim 1: to define the role of HIPK2 in cardiac fibrosis and remodeling. We will test the hypothesis that HIPK2 exerts a critical break on fibrotic remodeling by inhibiting profibrotic TGF-β1/SMAD-3 and p38 pathways. In Aim 2, we will test the hypothesis that CM-HIPK2 is essential in maintaining basal cardiac homeostasis and required to protect against cardiac stress. We will utilize inducible CM-specific cre mice to delete HIPK2 only in the fully mature CM, evaluate the mechanism(s) whereby HIPK2 may exert its cardioprotective effect. Aim 3 will assess the therapeutic efficacy of AAV9 mediated HIPK2 gene therapy to mitigate the pathologies induced by cardiac stress. Expression of HIPK2 is significantly reduced in failing human hearts, we hypothesize that restoration of HIPK2 in cardiac cells will reduce and may reverse the cardiac pathologies. AAV9-HIPK2 will be used to deliver the FB-specific (under periostin promoter and TCF21 promoter) and CM-specific (troponin-t promoter) gene expression. These studies will directly test the translational potential of the findings from Aims 1 and 2. Thus, the proposed studies are of high significance, not only by contributing translationally-relevant information but also by providing novel mechanistic insights into cardiac pathophysiology.