Parkin activators for cardioprotective therapies

心肌梗死伴左室重构是心力衰竭(HF)的主要原因。 目前的治疗方法不足以调节不利的重塑和预防随后的心力衰竭。AS 因此，人们迫切需要找到新的治疗方法，这种需求尚未得到满足。有强有力的证据表明，有丝分裂 心肌梗死(MI)后发挥心脏保护作用，线粒体生物发生受损 高频。线粒体功能障碍会减少能量产生，释放有害的活性氧物种，并 促炎症分子，参与导致心衰的缺血再灌注损伤。受监管和 PINK1激酶和Parkin泛素介导的有丝分裂选择性清除受损线粒体 连接酶，是线粒体质量控制的关键机制。此外，帕金已经被证明能够规范 泛素化和降解Pgc1的关键抑制子PARIS的有丝分裂作用 有丝分裂。出于这些原因，促进Parkin介导的线粒体质量控制的干预 途径是预防或改善心肌梗死后心力衰竭的一种有前景的治疗策略。帕金存在于一个 细胞中的自动抑制状态，并被PINK1激活。Progenra使用了一种新的tr-fret分析方法，并发现 选择性地结合和激活帕金的小分子。与Parkin激活剂一致，这些Parkin激活剂 化合物(PAC)降解Parkin底物(如PARIS)，并有效上调各种细胞的有丝分裂吞噬能力 模特们。此外，PAC还促进了永久性冠状动脉术后MitoTimer小鼠的线粒体周转 结扎组(PCAL)。最重要的是，PCAL后在小鼠体内注射PAC(1 mg/kg)会导致严重的 缓解不良心脏重构和纤维化导致心功能改善和野生动物存活 在PCAL后输入小鼠。因此，我们已经初步建立了PAC对心脏的保护作用的体内证据。在这 第一阶段计划，我们将使用成年大鼠的原代心肌细胞以及临床相关的饮食诱导的肥胖 建立小鼠PCAL模型，进一步评价和表征PACs的心脏保护作用。 心功能、存活率、纤维化、线粒体组成和功能的改善，以及 Parkin介导的泛素基因组的景观将被确定。在第二阶段，我们将评估长期安全性和 PAC在啮齿动物和猪模型中的疗效，特别是它们改善心肌梗死后心功能的能力， 减轻不良重塑，抑制先天免疫引起的炎症和纤维化。终极的 目标是开发可用于治疗心肌梗死后再灌注损伤和预防心脏的Parkin激活剂 失败了。

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.