Mitochondrial Fission, Calcium, ROS in Right Ventricular Fibrosis

右心室纤维化中的线粒体裂变、钙、ROS

基本信息

批准号：
10734675
负责人：
Bong Sook Jhun
金额：
$ 38.75万
依托单位：
UNIVERSITY OF MINNESOTA
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-07-01 至 2027-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10734675
关键词：
Antioxidants Apoptosis Apoptotic Attenuated Bax protein Calcium Cardiac Cardiac Myocytes Cause of Death Cell Membrane Permeability Cell Nucleus Chronic Clinical Collagen Cyclic AMP-Dependent Protein Kinases Data Development Dominant-Negative Mutation Dynamin Enzymes Extracellular Matrix Failure Fibroblasts Fibrosis Functional disorder Goals Injury Left Link Mediating Mitochondria Mitochondrial Proteins Modeling Molecular Myofibroblast Names Nuclear Nuclear Proteins Outcome Outer Mitochondrial Membrane Pathologic Patients Phenotype Phosphorylation Physiologic intraventricular pressure Process Prognosis Proliferating Protein Inhibition Proteins Pulmonary Hypertension Rattus Reactive Oxygen Species Reporting Research Resistance Right Ventricular Function Right Ventricular Hypertrophy Role Signal Transduction Stress Testing Ventricular conventional therapy coronary fibrosis design improved in vivo interstitial mitochondrial permeability transition pore mortality novel novel strategies novel therapeutic intervention novel therapeutics pre-clinical pressure pro-apoptotic protein protein kinase D pulmonary arterial hypertension response response to injury right ventricular failure therapeutic evaluation uptake

项目摘要

Project Summary: Growing evidence suggests the link between right ventricular (RV) fibrosis, poor function of the pressure-overloaded RV, and mortality in pulmonary arterial hypertension (PAH). PAH patients with decompensated RV failure (RVF) have persistent RV fibrosis even when treated with the conventional therapies for PAH. RVF is the main cause of death in PAH and maintaining RV function in PAH is associated with improved patient survival. However, there are currently no available therapies that specifically target RV fibrosis. Therefore, identifying the molecular mechanisms underlying RV fibrosis in PAH is urgently needed to develop novel therapeutic approaches targeting RVF in PAH. We recently reported the significant roles of o xidative stress-sensitive protein kinase D (PKD) at outer mitochondrial membrane (OMM) and its substrate dynamin-related protein 1 (DRP1), a mitochondrial fission protein, in dysregulating CM functions. We also showed that DRP1-mediated mitochondrial fission limits the size of the matrix cavity, thus causing elevated and sustained mitochondrial Ca2+ (mtCa2+) transient in response to cytosolic Ca2+ elevation. Using a preclinical rat PAH model with RV hypertrophy, failure, and fibrosis that significant , we found PKD activation and DRP1 phosphorylation occurs specifically in cardiac fibroblasts (CFs) in the RV (RV-CFs), but not in CMs under PAH, which subsequently causes an PKD-dependent increase in mitochondrial fission, mitochondrial reactive oxygen species (mROS), and CF proliferation. Moreover, we found that PKD activation is associated with increased phosphorylation of a pro-apoptotic protein Bax, which inhibits apoptotic pore formation in the OMM and potentially contributes to the anti-apoptotic phenotype of RV-CFs in PAH. Lastly, we also found that mtCa2+ uptake via mtCa2+ uniporter (MCU) is required for mROS elevation and subsequent activation of proliferative signaling in CFs. Based on these findings, we hypothesize that 1) PKD-dependent Bax phosphorylation allows RV-CFs to be resistant to apoptosis under PAH; 2) PKD-dependent mitochondrial fission limits mtCa2+ and antioxidant capacity by decreasing the size of the matrix cavity and causing increased mtCa2+ and mROS levels, thus acting as a molecular “switch” for proliferative signaling for RV-CFs in PAH; and 3) CF-specific inhibition of PKD at the OMM in vivo can be leveraged as a novel therapy to attenuate cardiac fibrosis in response to stress/injury such as PAH. In Aim 1, we will establish Bax as a novel PKD substrate in the mitochondria and assess the impact of PKD-dependent Bax phosphorylation on OMM permeability. To specifically inhibit PKD activity only at the OMM, we will use an OMM-targeted dominant-negative PKD1 (mt-PKD- DN) that we have newly validated. In Aim 2, we will test whether PKD-dependent enhancement of mitochondrial fission facilitates RV-CF proliferation via increased mtCa2+ and mROS levels. In Aim 3, we will test the therapeutic potential of mitochondrial PKD inhibition by mt-PKD-DN in the quiescent CFs before they transform into myofibroblasts by CF- specifically expressing mt-PKD-DN in a preclinical rat PAH model. The proposed project is designed to determine the role of mitochondrial fission, Ca2+, and mROS in RV-CF hyperproliferation and RV fibrosis in PAH, which will lead to develop a novel strategy (i.e., PKD inhibition) for the management of RV fibrosis and failure in the setting of PAH.

项目摘要：越来越多的证据表明，右心（RV）纤维化之间的联系，压力越过的功能较差 RV和肺动脉高压（PAH）的死亡率。 PAH失效失败（RVF）的患者患有即使使用PAH的常规疗法治疗，持续的RV纤维化也是如此。 RVF是死亡的主要原因 PAH和PAH中的RV功能与改善患者生存有关。但是，目前没有专门针对RV纤维化的可用疗法。因此，确定RV的分子机制迫切需要PAH中的纤维化来开发针对PAH的RVF的新型治疗方法。我们最近报道了O的重要作用 Xidativative应激敏感蛋白激酶 d（pkd）在外部线粒体膜（OMM）及其底物动力蛋白相关蛋白1（DRP1），一种线粒体裂变蛋白，在 CM功能失调。我们还表明DRP1介导的线粒体裂变限制了基质的大小腔，从而导致升高和持续的线粒体Ca2+（MTCA2+）瞬时响应胞质Ca2+升高。使用带有RV肥大，衰竭和纤维化的临床前大鼠PAH模型，我们发现 PKD激活 DRP1磷酸化特别发生在RV（RV-CFS）中的心脏成纤维细胞（CFS）中，但在CMS下不在 PAH随后导致线粒体裂变，线粒体活性氧的PKD依赖性增加物种（MRO）和CF增殖。此外，我们发现PKD激活与增加有关促凋亡蛋白Bax的磷酸化，该蛋白质抑制了OMM中的凋亡孔形成，并可能抑制有助于PAH中RV-CF的抗凋亡表型。最后，我们还发现MTCA2+通过MTCA2+吸收 MROS升高和随后在CFS中增殖信号传导激活所必需的。基于这些发现，我们假设1）依赖PKD的Bax磷酸化允许RV-CFS对凋亡具有抵抗力在PAH下； 2）通过降低大小基质腔并引起MTCA2+和MROS水平的增加，因此充当分子“开关” PAH中RV-CF的信号传导； 3）可以将体内PKD的CF特异性抑制作为一种新颖响应压力/损伤（例如PAH）的治疗，可减弱心脏纤维化。在AIM 1中，我们将建立Bax作为小说线粒体中的PKD底物并评估PKD依赖性BAX磷酸化对OMM渗透性的影响。为了特别抑制PKD活性，我们将使用符合OMM的主导性PKD1（MT-PKD-- DN）我们已获得新验证。在AIM 2中，我们将测试线粒体裂变的依赖PKD依赖性的增强通过升高的MTCA2+和MROS水平促进RV-CF增殖。在AIM 3中，我们将测试线粒体PKD通过MT-PKD-DN在静态CFS中抑制，然后通过CF-转化为肌纤维细胞在临床前大鼠PAH模型中特别表达MT-PKD-DN。拟议的项目旨在确定 PAH中线粒体裂变，Ca2+和MRO在RV-CF高增殖和RV纤维化中的作用，这将导致制定一种新的策略（即PKD抑制），以管理PAH的RV纤维化和失败。