Deciphering the role of lysosomal membrane permeabilization in Diabetic Cardiac Injury

项目摘要/摘要 糖尿病心肌病和心力衰竭是糖尿病患者死亡的主要原因。然而，有效的 目前仍缺乏预防和管理这种致命疾病的方法。我研究的长期目标是 目的是确定介导糖尿病心脏损伤的细胞和分子机制。溶酶体扮演着重要的角色 在细胞质质量控制和细胞内稳态中的作用。最近的研究证明了两者之间的联系 糖尿病心脏损伤和溶酶体途径紊乱之间的关系。溶酶体功能障碍的一个显著特征 是溶酶体膜通透性增加(LMP)，触发蛋白酶渗漏和细胞死亡。我们的 初步结果显示，糖尿病小鼠的心脏损害伴随着血管内皮生长因子表达的升高 组织蛋白酶D(CTSD)是一种主要的溶酶体蛋白水解酶。高糖诱导培养心肌细胞LMP， 导致CTSD的表达和分布发生改变。重要的是，CTSD的过度表达加剧了HIGH 葡萄糖诱导的心肌细胞死亡，而击倒CTSD或抑制CTSD活性则高度减弱 葡萄糖毒性。我们的假设是LMP的增加和随之而来的CTSD的泄漏和异常 蓄积介导糖尿病心脏损伤；从而增强溶酶体质量控制并将 CTSD的异位效应将保护糖尿病心脏。我们将追求两个具体目标来检验这一假设。 目标1将确定LMP和随之而来的CTSD渗漏是否会导致高血糖 心肌细胞死亡。目的探讨LMP在糖尿病心脏损伤中的病理意义。 糖尿病的小鼠模型。将使用药理学和遗传学方法来增强溶酶体 修复和调控CTSD的表达和成熟。糖尿病引起的溶酶体损伤将是 用一种新的LMP报告鼠系进行评估。改良CTSD对高血糖心脏毒性的影响 糖尿病心肌病将通过多种方法确定。本项目圆满完成 将为糖尿病心脏损伤的机制提供新的见解，促进药物设计 预防或治疗糖尿病的心肌病和心力衰竭。

PROJECT SUMMARY/ABSTRACT Diabetic cardiomyopathy and heart failure are a leading cause of death in diabetic patients. However, effective approaches to preventing and managing this deadly disease are still lacking. The long-term goal of my research is to identify cellular and molecular mechanisms that mediate diabetic cardiac injury. Lysosomes play important roles in cytoplasmic quality control and cellular homeostasis. Recent studies have demonstrated an association between diabetic cardiac injury and a disturbed lysosome pathway. A prominent feature of lysosomal dysfunction is increased lysosomal membrane permeabilization (LMP) which triggers protease leakage and cell death. Our preliminary results showed that cardiac damage in diabetic mice was accompanied by elevated expression of cathepsin D (CTSD), a major lysosomal protease. High glucose induced LMP in cultured cardiomyocytes, leading to altered expression and distribution of CTSD. Importantly, CTSD overexpression exacerbated high glucose-induced cardiomyocyte death, while knocking down CTSD or inhibiting CTSD activity attenuated high glucose toxicity. Our hypothesis is that the increased LMP and the ensuing CTSD leakage and aberrant accumulation mediate diabetic cardiac injury; thus enhancing lysosomal quality control and minimizing the ectopic effects of CTSD will protect the diabetic heart. We will pursue two specific aims to test this hypothesis. Aim 1 will determine whether LMP and the ensuing CTSD leakage contributes to hyperglycemia-induced cardiomyocyte death. Aim 2 will investigate the pathological significance of LMP in diabetic heart injury using mouse models of diabetes. Pharmacological and genetic approaches will be used to enhance the lysosomal repair and to manipulate the expression and maturation of CTSD. Diabetes-induced lysosomal injury will be assessed with a novel LMP reporter mouse line. The effects of altered CTSD on hyperglycemic cardiotoxicity and diabetic cardiomyopathy will be determined with multiple approaches. Successful completion of this project will provide novel insight into the mechanisms that mediate diabetic cardiac injury, facilitating drug design for preventing or treating cardiomyopathy and heart failure in diabetes.