The Role of Arginine Transport on Pancreatic Alpha Cell Proliferation and Function

精氨酸转运对胰腺α细胞增殖和功能的作用

• 批准号: 10678248
• 负责人: Jade Elise Stanley
• 金额: $ 3.3万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-01 至 2026-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10678248
• 关键词: Affect; Alpha Cell; Amino Acid Transporter; Amino Acids; Arginine; Basic Amino Acid Transport Systems; Blood; CRISPR/Cas technology; Calcium; Cations; Cause of Death; Cell Proliferation; Cell physiology; Cell secretion; Cells; Chemicals; Clinical Trials; Co-Immunoprecipitations; Data; Development; Diabetes Mellitus; Disease Progression; Endocrine; Environment; Enzyme Inhibition; FRAP1 gene; Failure; Feedback; Fellowship; Functional disorder; Future; Glucagon; Gluconeogenesis; Glucose; Glutamine; Hormone secretion; Human; Hyperglycemia; Hyperplasia; Image; Immunohistochemistry; Impairment; Incubated; Individual; Insulin; Insulin-Dependent Diabetes Mellitus; Interruption; Islets of Langerhans; Knock-out; Knockout Mice; Liver; Measures; Membrane; Mentors; Mentorship; Metabolism; Modeling; Modification; Molecular; Monitor; Mus; Nitric Oxide; Nitric Oxide Pathway; Non-Insulin-Dependent Diabetes Mellitus; Nutrient; Pathway interactions; Physiological; Production; Proliferating; Property; Proteins; Qualifying; Regulation; Research; Resources; Rodent Model; Role; Scientist; Signal Transduction; Structure of alpha Cell of islet; Structure of beta Cell of islet; System; Testing; Therapeutic; Tissues; Training; Transgenic Mice; Western Blotting; Work; arginase; blood glucose regulation; calcium indicator; career; combat; experimental study; hyperglucagonemia; in vivo Model; insulin secretion; islet; mouse model; new therapeutic target; protein protein interaction; sensor; small molecule; tool

Project Summary The training strategy demonstrated in this document will help me advance my career to be an independent research scientist in the field of diabetes. I propose to assess the role of arginine transport in the regulation of pancreatic islet cell proliferation and hormone secretion. Disease progression of diabetes is attributed to the inability of pancreatic β-cells to sufficiently secrete insulin and the combined failure to suppress pancreatic α-cell secretion of glucagon. Inhibition of glucagon signaling reduces hyperglycemia for individuals with diabetes.3 However, impairment of glucagon signaling leads to hyperglucagonemia, hyperaminoacidemia, and α-cell proliferation.4,5 Our lab has identified a liver-α-cell axis that contributes to α-cell proliferation through the accumulation of amino acids in the blood.4 We have identified two major amino acids that contribute to α-cell proliferation, glutamine4 and arginine (unpublished data). However, the mechanisms underlying arginine transport in the α-cell specifically and its contribution to α-cell proliferation and secretion are not well defined. The cationic amino acid transporter SLC7A2 is highly expressed in mouse and human pancreatic α-cells. Therefore, we hypothesize that hyperaminoacidemia that results from interrupted glucagon signaling contributes to increased arginine transport promoting α-cell proliferation and dysfunction. Our preliminary studies show that SLC7A2 is required for α-cell proliferation and glucagon secretion even when challenged with strong membrane depolarizing agents challenging current cation-centric models of arginine stimulated secretion (Figure 2 and 4). Using a new α-cell specific Slc7a2 knockout mouse model, we will unravel the molecular mechanisms that lead to arginine-stimulated α-cell proliferation and glucagon secretion. To assess whether SLC7A2 in α-cells is necessary for amino acid-dependent α-cell proliferation, Slc7a2 knockout in immortalized mouse αTC1-6 cells and an inducible α-cell specific Slc7a2 knockout mouse model will be used to assess changes in α-cell proliferation and mass. Additionally, the mechanism of arginine-induced mTORC1 activation will be targeted to determine if arginine activates mTORC1 through the inactivation of the CASTOR1- GATOR2 pathway (Aim 1). Furthermore, to test the ability for arginine transport via SLC7A2 to modulate glucagon secretion we will combine tools used in Aim 1 with chemical and genetically encoded Ca2+ sensors to observe changes in α-cell glucagon secretion. We will also measure nitric oxide levels, and test the affect of nitric oxide on glucagon secretion to understand the mechanism behind arginine-induced glucagon secretion (Aim 2). Successfully accomplishing this study will enhance our current understanding of amino acid-induced α- cell proliferation and function, as well as broaden the possibilities of therapeutic treatments for diabetes. My training will be achieved through the execution of this study utilizing the fantastic resources and facilities provided by Vanderbilt and thorough mentorship from my highly qualified mentors, Drs. Danielle Dean and David Jacobsen.

项目摘要 本文档中展示的培训策略将帮助我发展职业成为一个 糖尿病领域的独立研究科学家。我建议评估精氨酸转运在 调节胰岛胰岛细胞增殖和骑马分泌。糖尿病的疾病进展是 归因于胰腺β细胞无法充分分泌胰岛素的能力，而抑制的综合失败 胰高血糖素的胰腺α细胞分泌。胰高血糖素信号传导的抑制可降低个体的高血糖 3然而，胰高血糖素信号传导的损害会导致高葡萄糖血症，高氨基酸血症，高氨基酸血症， 和α细胞增殖。4,5我们的实验室已经确定了一个肝脏-α细胞轴，该轴有助于通过 氨基酸在血液中的积累。4我们已经确定了两个有助于α细胞的主要氨基酸 增殖，谷氨酰胺4和精氨酸（未发表的数据）。但是，精氨酸的基础机制 特别定义了α细胞的转运及其对α细胞增殖和分泌的贡献。 阳离子氨基酸转运蛋白SLC7A2在小鼠和人胰腺α细胞中高度表达。 因此，我们假设由中断胰高血糖传导引起的高氨基酸血症 有助于增加精氨酸转运，从而促进α细胞增殖和功能障碍。我们的 初步研究表明，即使在 通过强膜去极化剂挑战挑战精氨酸的当前以阳离子为中心的模型 刺激的分泌（图2和4）。使用新的α细胞特异性SLC7A2基因敲除鼠标模型，我们将解开 导致精氨酸刺激的α细胞增殖和臀部分泌的分子机制。评估 α细胞中的SLC7A2是否对于氨基酸依赖性α细胞增殖需要SLC7A2敲除 永生的小鼠αTC1-6细胞和可诱导的α细胞特异性SLC7A2基因敲除小鼠模型将用于 评估α细胞增殖和质量的变化。此外，精氨酸诱导的MTORC1的机制 激活将是针对确定精氨酸是否通过castor1-灭活激活mTORC1的目标的。 Gator2途径（AIM 1）。此外，要测试通过SLC7A2调节精氨酸传输的能力 胰高血糖素的分泌我们将将AIM 1中使用的工具与化学和遗传编码的CA2+传感器相结合 观察α细胞斜肌分泌的变化。我们还将测量一氧化氮水平，并测试 一氧化氮在胰高血糖素分泌上，以了解精氨酸诱导的胰高血糖素分泌的机制 （目标2）。成功完成这项研究将增强我们当前对氨基酸诱导的α-的理解 细胞增殖和功能，并扩大糖尿病治疗治疗的可能性。我的 利用提供的精彩资源和设施的执行将实现培训 通过我高素质的心态，博士的范德比尔特和诚实的心态。丹妮尔·迪恩（Danielle Dean）和大卫（David） 雅各布森。