Mitochondrial Dysfunction, Permeability Transition Pore, and Acute Pancreatitis

线粒体功能障碍、渗透性转变孔和急性胰腺炎

• 批准号: 8242610
• 负责人: ANNA S. GUKOVSKAYA
• 金额: --
• 依托单位: VA GREATER LOS ANGELES HEALTHCARE SYSTEM
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-10-01 至 2014-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8242610
• 关键词: Acinar Cell; Applied Genetics; Autophagocytosis; Cathepsins; Cell Death; Cells; Data; Disease; Drops; Enzymes; Exocrine pancreas; Experimental Models; Functional disorder; Goals; Impairment; Inflammatory Response; Investigation; Knockout Mice; Link; Lysosomes; Mediating; Membrane Potentials; Mitochondria; Modeling; Molecular; Mus; Organelles; Pancreas; Pancreatitis; Pathogenesis; Pathologic; Permeability; Process; Property; Publishing; Reactive Oxygen Species; Research; Role; Severities; Therapeutic; Transfection; Trypsin; Trypsinogen; Vacuole; acute pancreatitis; base; cyclophilin D; in vitro Model; in vivo; insight; lysosomal proteins; mitochondrial dysfunction; mitochondrial membrane; mitochondrial permeability transition pore; novel therapeutics; patient population; premature; protein degradation; public health relevance; research study; response; tool

DESCRIPTION (provided by applicant): MITOCHONDRIAL DYSFUNCTION, PERMEABILITY TRANSITION PORE, AND ACUTE PANCREATITIS Key words: acute pancreatitis, pancreatic acinar cell, mitochondria, permeability transition pore, lysosomes, cathepsin, autophagy, trypsin, vacuoles. Aims: Acute pancreatitis is a potentially fatal disease of exocrine pancreas, the pathogenesis of which remains obscure and specific treatments for which do not exist. Intra-acinar trypsinogen activation and formation of large vacuoles are key early pathologic responses of pancreatitis. Our recent studies revealed that acute pancreatitis causes profound impairment of autophagy, the main cellular degradative, lysosome-driven process. We showed that autophagy impairment results from defective, inefficient lysosomal protein degradation and mediates the accumulation of vacuoles and trypsin in acinar cells. On the other hand, we found that mitochondrial dysfunction, manifest by loss of the mitochondrial membrane potential (DYm), is a common response in models of acute pancreatitis. The principal mechanism of mitochondrial depolarization is through opening of permeability transition pore (PTP), a non-selective channel in the mitochondrial membrane. The overall goal of this proposal is to determine whether the dysfunctions of 2 critical organelles, the lysosomes and mitochondria, are linked; that is, whether PTP-dependent mitochondrial depolarization mediates lysosomal dysfunction, autophagy impairment, acinar cell vacuolization and trypsinogen activation in pancreatitis. We will use experimental in vivo and in vitro models of pancreatitis to determine PTP-mediated changes in DYm and mitochondrial reactive oxygen species (ROS), and the roles of PTP and mitochondrial ROS in the above-referred pathologic responses. For this purpose, we will apply genetic (knockout mice), molecular (transfections), and pharmacologic approaches. Our hypothesis states that PTP opening, which results in DYm loss and drop in mitochondrial ROS, mediates key pathologic responses of acute pancreatitis. Further, mitochondrial dysfunction mediates the defective lysosomal protein degradation and autophagy in pancreatitis, underlying acinar cell vacuolization and trypsinogen activation. An important mechanism linking the mitochondrial and lysosomal dysfunctions in pancreatitis is the PTP-mediated decrease in mitochondrial ROS. Based on our published and preliminary data for this application, we propose that PTP inactivation represents a promising novel therapeutic strategy to treat or mitigate the severity of acute pancreatitis. Research Plan: Specific Aims of our proposal are: (1). Determine the effect of PTP on DYm and ROS in in vivo and in vitro models of acute pancreatitis. (2). Determine the role of PTP in lysosomal dysfunction and impaired autophagy, underlying acinar cell vacuolization and trypsinogen activation in in vivo and in vitro models of pancreatitis.(3). Determine the role of mitochondrial ROS in lysosomal dysfunction, impaired autophagy, acinar cell vacuolization and trypsinogen activation in the in vitro model of pancreatitis. (4). Determine the effects of pharmacologic PTP inhibition on pathologic responses of acute pancreatitis. PUBLIC HEALTH RELEVANCE: Acute pancreatitis is a potentially fatal disease of exocrine pancreas, the pathogenesis of which remains unknown and specific treatments for which have not been developed. This disease is common in VA patient population. Our recent studies revealed that acute pancreatitis causes profound dysfunction of 2 critical cellular organelles, the mitochondria and the lysosomes. This proposal will use experimental models in mice and isolated cells to determine the molecular mechanisms of these dysfunctions, the link between them, and their roles in key pathologic responses of pancreatitis (such as accumulation of large vacuoles in pancreas and the premature, intrapancreatic activation of digestive enzymes). Further, based on the mechanism, we propose a novel therapeutic strategy to correct the mitochondrial and lysosomal dysfunctions and thus to treat or mitigate the severity of pancreatitis.

描述（由申请人提供）： 关键词：急性胰腺炎，胰腺腺泡细胞，线粒体，通透性转换孔，溶酶体，组织蛋白酶，自噬，胰蛋白酶，空泡。 目的：急性胰腺炎是胰腺外分泌部的一种潜在致死性疾病，其发病机制尚不清楚，也没有特异性治疗方法。腺泡内胰蛋白酶原激活和大空泡形成是胰腺炎的关键早期病理反应。我们最近的研究表明，急性胰腺炎会导致自噬的严重损害，自噬是主要的细胞降解，溶酶体驱动的过程。我们发现自噬损伤是由于溶酶体蛋白质降解的缺陷和低效引起的，并介导了腺泡细胞中空泡和胰蛋白酶的积累。另一方面，我们发现线粒体功能障碍（表现为线粒体膜电位（DYm）丧失）是急性胰腺炎模型中的常见反应。线粒体去极化的主要机制是通过开放线粒体膜上的非选择性通道--通透性转换孔（PTP）。 本提案的总体目标是确定2个关键细胞器（溶酶体和线粒体）的功能障碍是否相关;即，PTP依赖性线粒体去极化是否介导胰腺炎中的溶酶体功能障碍、自噬损伤、腺泡细胞空泡化和胰蛋白酶原激活。我们将使用胰腺炎的体内和体外实验模型来确定PTP介导的DYm和线粒体活性氧（ROS）的变化，以及PTP和线粒体ROS在上述病理反应中的作用。为此，我们将应用遗传（敲除小鼠），分子（转染）和药理学方法。我们的假设指出，PTP开放，导致DYm损失和线粒体ROS下降，介导急性胰腺炎的关键病理反应。此外，线粒体功能障碍介导胰腺炎中的溶酶体蛋白降解和自噬缺陷，导致腺泡细胞空泡化和胰蛋白酶原活化。在胰腺炎中连接线粒体和溶酶体功能障碍的一个重要机制是PTP介导的线粒体ROS减少。基于我们已发表的和初步的数据，我们认为PTP失活是一种很有前途的新的治疗策略，可以治疗或减轻急性胰腺炎的严重程度。 研究计划：我们的建议的具体目标是：（1）。在急性胰腺炎的体内和体外模型中确定PTP对DYm和ROS的影响。（二）、在胰腺炎的体内和体外模型中确定PTP在溶酶体功能障碍和受损的自噬、潜在的腺泡细胞空泡化和胰蛋白酶原激活中的作用。（三）、在胰腺炎体外模型中，确定线粒体ROS在溶酶体功能障碍、自噬受损、腺泡细胞空泡化和胰蛋白酶原激活中的作用。（四）、确定药物PTP抑制对急性胰腺炎病理反应的影响。 公共卫生关系：急性胰腺炎是胰腺外分泌部的一种潜在的致命性疾病，其发病机制尚不清楚，也没有开发出特异性治疗方法。这种疾病在VA患者人群中很常见。我们最近的研究表明，急性胰腺炎导致2个关键细胞器，线粒体和溶酶体的严重功能障碍。该提案将使用小鼠和分离细胞的实验模型来确定这些功能障碍的分子机制，它们之间的联系，以及它们在胰腺炎关键病理反应中的作用（例如胰腺中大空泡的积累和消化酶的过早胰腺内激活）。此外，基于该机制，我们提出了一种新的治疗策略，以纠正线粒体和溶酶体功能障碍，从而治疗或减轻胰腺炎的严重程度。