The role of neprilysin in pancreatic beta-cell dysfunction and death

脑啡肽酶在胰腺β细胞功能障碍和死亡中的作用

• 批准号: 8423347
• 负责人: Sakeneh Zraika
• 金额: $ 23.86万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-04-01 至 2015-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8423347
• 关键词: Address; Angiotensin I; Award; B-Lymphocytes; Beta Cell; Blood Glucose; Cell physiology; Cells; Cessation of life; Chronic; Chronic Disease; Data; Defect; Development; Diet; Failure; Fatty acid glycerol esters; Functional disorder; Glucose; Hour; Hyperglycemia; Hyperlipidemia; Impairment; In Vitro; Infusion procedures; Instruction; Insulin; Islets of Langerhans; Measures; Mediating; Mus; Neprilysin; Non-Insulin-Dependent Diabetes Mellitus; Oxidative Stress Induction; Pathway interactions; Peptide Hydrolases; Peptides; Phase; Play; Protein Inhibition; Proteins; Renin-Angiotensin System; Role; Structure of beta Cell of islet; Tissues; base; carbohydrate metabolism; feeding; improved; in vivo; insulin secretion; islet; lipid metabolism; prevent; protein metabolism; response; stressor; therapeutic development

Islet beta-cell failure is central to the development of type 2 diabetes and is contributed to by both hyperglycemia and hyperlipidemia. The protein neprilysin, a component ofthe renin-angiotensin system (RAS), has been shown in non-islet tissues to be upregulated with the chronically elevated glucose and fat levels seen in type 2 diabetes. While the function of neprilysin in islets has not been investigated, we have data that show it is synthesized and active in islets and may play a role in the modulation of beta-cell function in response to islet stressors. Thus, the overall aim of this proposal is to elucidate the role of neprilysin under conditions associated with impaired beta-cell function, namely increased fat and glucose. We hypothesize that in states of chronically elevated fat and glucose, neprilysin activity is upregulated thereby promoting beta-cell dysfunction. During the K99 phase of this award, studies were conducted to determine the contribution of neprilysin to impaired insulin secretion induced by chronically elevated fat. Our findings demonstrate that neprilysin is indeed upregulated under conditions of chronically elevated fat and this is associated with reduced glucosestimulated insulin secretion in vitro. Moreover, neprilysin deficient (NEP-KO) mice fed a high fat diet are protected from high fat diet-induced reductions in glucose-stimulated insulin secretion in vivo. During the ROO phase of this award, the following studies will be performed to determine: 1) The role of neprilysin in the impairment Of insulin secretion induced by chronically elevated glucose. Our preliminary data suggest that neprilysin may also be upregulated under high glucose conditions and thereby may mediate the induction of oxidative stress. Firstly, NEP-KO mice will receive a 48-hour glucose infusion to induce hyperglycemia, then insulin secretion wil! be measured in vivo. Secondly, isolated islets from NEPKO mice will be cultured in high glucose and insulin secretion will be examined in vitro. 2) The role ofthe RAS in mediating neprilysin's effects under chronically elevated fat and glucose conditions. Since neprilysin is a component of the RAS, isolated islets will be used to determine whether neprilysin's activity in this pathway is responsible for impaired beta-cell function.

胰岛 β 细胞衰竭是 2 型糖尿病发展的核心，由以下因素共同促成： 高血糖和高脂血症。中性溶酶蛋白，肾素-血管紧张素系统的一个组成部分 (RAS)，已被证明在非胰岛组织中随着葡萄糖和脂肪的长期升高而上调 2 型糖尿病中所见的水平。虽然脑啡肽酶在胰岛中的功能尚未被研究，但我们已经 数据显示它在胰岛中合成并具有活性，并且可能在调节 β 细胞功能中发挥作用 响应胰岛应激源。因此，该提案的总体目标是阐明脑啡肽酶在 与β细胞功能受损相关的疾病，即脂肪和葡萄糖增加。我们假设 在脂肪和葡萄糖长期升高的状态下，脑啡肽酶活性上调，从而促进 β细胞功能障碍。 在该奖项的 K99 阶段，进行了研究以确定脑啡肽酶对 长期升高的脂肪导致胰岛素分泌受损。我们的研究结果表明脑啡肽酶 在长期脂肪升高的情况下确实上调，这与葡萄糖刺激的减少有关 体外胰岛素分泌。此外，喂食高脂肪饮食的脑啡肽酶缺乏（NEP-KO）小鼠 防止高脂肪饮食引起的体内葡萄糖刺激的胰岛素分泌减少。 在该奖项的原产地规则阶段，将进行以下研究以确定： 1) 脑啡肽酶在慢性血糖升高引起的胰岛素分泌受损中的作用。我们的 初步数据表明，脑啡肽酶在高葡萄糖条件下也可能上调，从而 可能介导氧化应激的诱导。首先，NEP-KO小鼠将接受48小时的葡萄糖输注 诱发高血糖，然后胰岛素就会分泌！在体内进行测量。其次，从 NEPKO 中分离出胰岛 小鼠将在高葡萄糖条件下培养，并在体外检查胰岛素分泌情况。 2) RAS在长期升高的脂肪和葡萄糖下介导脑啡肽酶作用中的作用 状况。由于脑啡肽酶是 RAS 的一个组成部分，因此将使用分离的胰岛来确定是否 脑啡肽酶在该途径中的活性导致β细胞功能受损。