Parkin activators for cardioprotective therapies

心肌梗死后左心室重构是心力衰竭（HF）的主要原因。 目前的治疗不足以调节不良重塑和预防随后的心力衰竭。作为 因此，存在识别新疗法的关键的未满足的需求。有强有力的证据表明线粒体自噬 心肌梗死（MI）后发挥心脏保护作用，线粒体生物合成受损有助于 HF。线粒体功能障碍减少能量产生，释放有害的活性氧， 促炎分子，其促成导致HF的缺血再灌注损伤。规范和 通过PINK 1激酶和帕金泛素协调的线粒体自噬选择性清除受损的线粒体 连接酶是关键的线粒体质量控制机制。此外，帕金已被证明可以调节 有丝分裂通过泛素化和降解巴黎，PGC 1 β的关键阻遏物，PGC 1 β的正调节因子， 有丝分裂由于这些原因，干预促进了帕金森介导的线粒体质量控制 心肌梗死后心功能不全是一种有前途的预防或改善心肌梗死后心力衰竭的治疗策略。帕金存在于 细胞中的自抑制状态，并被PINK 1激活。Progenra使用了一种新的TR-FRET测定法， 选择性结合并激活帕金的小分子。与帕金激活一致，这些帕金激活剂 化合物（PAC）降解帕金底物（例如巴黎）并有效地上调各种细胞中的线粒体自噬 模型此外，PAC促进Mitotimer小鼠在永久性冠状动脉栓塞后的线粒体更新。 连接（PCAL）。最重要的是，在小鼠PCAL后给予PAC（1 mg/kg）导致了深刻的 减轻不利的心脏重塑和纤维化，从而改善心脏功能和野生型的存活率。 型小鼠。因此，我们已经建立了初步的体内证明的心脏保护PAC。在这 第一阶段的建议，我们将使用成年大鼠原代心肌细胞以及临床相关的饮食诱导的肥胖 小鼠模型进行了PACAL，以进一步评估和表征PAC的心脏保护作用。 心脏性能、存活率、纤维化、线粒体组成和功能的改善， 将确定帕金森介导的遍在蛋白组的景观。在第二阶段，我们将评估长期安全性， PAC在啮齿动物和猪模型中的功效，特别是其改善MI后心脏功能的能力， 减弱不利的重塑，并抑制由先天免疫驱动的炎症和纤维化。最终 本研究的目的是开发可用于治疗MI后再灌注损伤和预防心脏病的Parkin激活剂。 失败

Myocardial infarction followed by left ventricular remodeling is the leading cause of heart failure (HF). Current therapies are inadequate to modulate adverse remodeling and prevent subsequent cardiac failures. As such there is a critical unmet need to identify new therapies. There is strong evidence suggesting that mitophagy exerts cardioprotective effects following infarction (MI) and that impaired mitochondrial biogenesis contributes to HF. Mitochondrial dysfunction reduces energy production, releasing harmful reactive oxygen species and proinflammatory molecules, which contribute to the ischemic reperfusion injury leading to HF. Regulated and selective clearance of damaged mitochondria via mitophagy orchestrated by PINK1 kinase and Parkin ubiquitin ligase, is a key mitochondrial quality control mechanism. Moreover, Parkin has been shown to regulate mitogenesis by ubiquitinating and degrading PARIS, a key repressor of PGC1, the positive regulator of mitogenesis. For these reasons, intervention to promote the Parkin-mediated mitochondrial quality control pathway is a promising therapeutic strategy to prevent or ameliorate post-MI heart failure. Parkin exists in an auto-inhibited state in cells and is activated by PINK1. Progenra utilized a novel TR-FRET assay and discovered small molecules that bind and activate Parkin selectively. Consistent with Parkin activation, these Parkin activator compounds (PACs) degrade Parkin substrates (e.g. PARIS) and potently upregulate mitophagy in various cell models. In addition, PACs promoted mitochondrial turnover in Mitotimer mice after permanent coronary artery ligation (PCAL). Most important, administration of PAC (1mg/kg) in mice after PCAL resulted in profound mitigation of adverse cardiac remodeling and fibrosis leading to improved cardiac function and survival of wild type mice after PCAL. Thus, we have established preliminary in vivo proof of cardioprotection by PAC. In this phase I proposal, we will use adult rat primary cardiomyocytes as well as clinically relevant diet-induced obesity mouse model subjected to PCAL to further evaluate and characterize the cardioprotective role of PACs. Improvements in cardiac performance, survival, fibrosis, mitochondrial composition and function, and the landscape of Parkin-mediated ubiquitylome will be determined. In Phase II, we will evaluate long-term safety and efficacy of PACs in rodent and swine models, particularly their ability to improve cardiac functions post-MI, attenuate adverse remodeling, and suppress inflammation and fibrosis driven by innate immunity. The ultimate goal is the development of Parkin activator that can be used to treat post-MI reperfusion injury and prevent heart failure.