Role of proteolytic suPAR fragment in insulin dependent diabetes and kidney disease

蛋白水解suPAR片段在胰岛素依赖性糖尿病和肾脏疾病中的作用

• 批准号: 10654224
• 负责人: Jochen Reiser
• 金额: $ 69.56万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-01 至 2028-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10654224
• 关键词: Address; Applications Grants; Chronic; Chronic Kidney Failure; Clinical; Complications of Diabetes Mellitus; Cyclic GMP; Data; Development; Diabetes Mellitus; Diabetic Nephropathy; Disease; Disease Progression; Drug Targeting; Epidemic; Etiology; Female; Fibrosis; Goals; Gonadal Steroid Hormones; Human; Inflammation; Inflammatory; Injury; Injury to Kidney; Insulin-Dependent Diabetes Mellitus; Kidney; Kidney Diseases; Knowledge; Link; Malignant Neoplasms; Mitochondria; Modeling; Molecular; Non obese; Organ; Pancreas; Pathway interactions; Pharmaceutical Preparations; Pharmacologic Substance; Physiological; Pilot Projects; Plasma; Play; Population; Publishing; Rattus; Renin-Angiotensin-Aldosterone System; Reporting; Research; Risk Factors; Role; Sex Differences; Signal Pathway; Signaling Protein; Stimulator of Interferon Genes; Structure of beta Cell of islet; Study models; Therapeutic; Tubular formation; Type 2 diabetic; Urokinase; Virulence Factors; Woman; cell type; defined contribution; design; diabetic; disease phenotype; drug development; hypertensive; in vivo; inhibitor; interest; male; men; novel; podocyte; receptor; sex; sexual dimorphism; translational potential

The global epidemic of chronic kidney disease (CKD) is progressing at an alarming rate. CKD affects an estimated 37 million people in the U.S. (15% of the adult population; more than 1 in 7 adults), and this number has more than doubled in the last two decades. Kidney-related diseases are rapidly eluding present treatment options and resources. The three common causes of CKD are diabetes mellitus, hypertension, and glomerulonephritis. We and others have implicated soluble urokinase activating receptor (suPAR) as one of the significant risk factors for both, the onset as well as the progression of CKD, regardless of its etiologies. In addition to its role as a biomarker, we and others have suggested that suPAR is a pathogenic/scarring factor that underlies podocyte injury by activating v3 integrin on podocytes. Podocytes are terminally differentiated cells essential for maintaining the specificity of the kidney filter. Our preliminary data suggest that the presence of the proteolytic fragment of suPAR, D2D3 fragment, in the plasma induces glomerular injury by activating v3 integrin on podocytes. In addition, and highly unexpectedly, our preliminary studies suggest that the D2D3 fragment also injures -cells of the pancreas. Together, these insights suggest a hypothesis that circulating D2D3 fragment simultaneously causes injury to two organs, the kidney and pancreas. We test this hypothesis in 3 Specific Aims. In Specific Aim 1, we define the physiological mechanisms by which D2D3 induces kidney and pancreas injuries by examining organ functions in D2D3-Tg mice on regular- and high-fat- diet challenged by nephrotoxic serum or Adriamycin. In addition, we will cross D2D3-Tg mice with Non-Obese Diabetic (NOD) mice to examine synergy upon pancreas injury. Anti-suPAR antibodies and small molecules that target regulatory GTPases (dynamin, Cdc42, Rac1), whose roles will be elucidated in Aims 2 and 3, will be tested as potential therapeutics. As D2D3-Tg mice exhibit dual organ injury, combination treatments targeting diverse pathways in distinct cell types will also be investigated. In Specific Aim 2, we examine the effects of the D2D3 fragment on the actin cytoskeleton, regulatory GTPases, mitochondrial function, and gene expression in terminally differentiated and primary podocytes in the presence and absence of lipotoxic stimuli or high glucose levels. We focus on the effects of D2D3 on a feedback loop between the actin cytoskeleton and mitochondrial function, and its modifications by changes in podocyte physiology. In Specific Aim 3, we examine the effects of D2D3 on glucose uptake, intracellular Ca2+ dynamics, cytoskeleton dynamics, and gene expression in -cells, isolated mouse islets, and tissue slices. The proposed study, delineating molecular mechanisms and the physiological relevance of dual organ injury, is a critical step in developing novel mechanism-specific therapeutics for CKD and insulin-dependent diabetes mellitus.

慢性肾脏病(CKD)的全球流行正以惊人的速度发展。据估计，美国有3700万人患有慢性肾脏病(占成年人口的15%；超过七分之一的成年人)，这个数字在过去20年里翻了一番多。与肾脏相关的疾病正在迅速避开目前的治疗选择和资源。慢性肾脏病的三个常见原因是糖尿病、高血压和肾小球肾炎。我们和其他人认为，无论病因如何，可溶性尿激活素受体(SuPAR)都是CKD发病和发展的重要危险因素之一。除了作为生物标志物的作用外，我们和其他人还认为suPAR是一种致病/瘢痕因子，通过激活足细胞上的v3整合素而导致足细胞损伤。足细胞是终末分化的细胞，对维持肾脏滤器的特异性是必不可少的。我们的初步数据表明，血浆中存在suPAR的蛋白水解性片段D2D3片段，通过激活足细胞上的v3整合素来诱导肾小球损伤。此外，非常出人意料的是，我们的初步研究表明，D2D3片段还会损伤胰腺的细胞。综上所述，这些见解提出了一种假设，即循环中的D2D3片段同时会对肾脏和胰腺这两个器官造成损害。我们从三个具体的目标来检验这一假设。在具体目标1中，我们通过检测肾毒性血清或阿霉素攻击的正常和高脂饮食D2D3-TG小鼠的器官功能，确定了D2D3导致肾脏和胰腺损伤的生理机制。此外，我们将D2D3-TG小鼠与非肥胖糖尿病(NOD)小鼠杂交，以检查对胰腺损伤的协同作用。针对调节GTP酶的抗suPAR抗体和小分子(Dynamin，CDC42，rac1)，其作用将在AIMS 2和3中阐明，将作为潜在的治疗药物进行测试。由于D2D3-TG小鼠表现出双重器官损伤，针对不同细胞类型的不同途径的联合治疗也将被研究。在特定的目标2中，我们研究了D2D3片段在存在和不存在脂毒刺激或高糖水平的情况下对终末分化和初级足细胞的肌动蛋白细胞骨架、调节性GTP酶、线粒体功能和基因表达的影响。我们着重于D2D3在肌动蛋白细胞骨架和线粒体功能之间的反馈环路中的作用，以及它通过足细胞生理变化进行的修饰。在特定的目标3中，我们研究了D2D3对细胞、分离的小鼠胰岛和组织切片中葡萄糖摄取、细胞内钙动力学、细胞骨架动力学和基因表达的影响。这项研究描绘了双器官损伤的分子机制和生理相关性，是开发针对慢性肾脏病和胰岛素依赖型糖尿病的新机制特异性疗法的关键一步。