Role of pH-mediated metabolic reprogramming in β cell failure in Type 2 Diabetes Mellitus

pH 介导的代谢重编程在 2 型糖尿病β细胞衰竭中的作用

• 批准号: 10724745
• 负责人: ALEKSEY V MATVEYENKO
• 金额: $ 14.19万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-04-01 至 2024-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10724745
• 关键词: Acids; Address; Alkalinization; Animal Model; Attenuated; Autopsy; Beta Cell; Bicarbonates; Buffers; Cell physiology; Cells; Collection; Compensation; Coupled; Development; Diabetes Mellitus; Etiology; Exposure to; Failure; Family; Fasting; Functional disorder; Genes; Genetic; Glucose; Goals; Health; Healthcare Systems; Human; Hyperglycemia; Impairment; Insulin; Insulin Resistance; Ion Pumps; Islets of Langerhans; Knock-out; Longevity; Measures; Mediating; Metabolic; Mitochondria; Molecular; Mus; Non-Insulin-Dependent Diabetes Mellitus; Obesity; Pancreas; Persons; Phenotype; Physiological; Physiology; Prediabetes syndrome; Prevalence; Prevention strategy; Production; Proteins; Regulation; Role; Structure of beta Cell of islet; Testing; Training; Work; cancer cell; combat; diabetogenic; functional decline; gain of function; glucose metabolism; improved; insulin secretion; islet; loss of function; mitochondrial metabolism; novel; novel therapeutic intervention; obese patients; overexpression; parent project; preservation; public health relevance; response; sensor; stressor; symporter; therapeutic evaluation; tool; treatment strategy

DEI Supplement R01-DK128844: Supplement abstract Type 2 diabetes mellitus (T2DM) manifests through the development of fasting and postprandial hyperglycemia the etiology of which can be distilled to failure of pancreatic β cells to maintain appropriate glucose-stimulated insulin secretion (i.e., β cell function) to compensate for the decline in insulin action (i.e. insulin resistance). Part of our ongoing studies indicate that SLC4A4 and its protein product (electrogenic Na+ -coupled HCO3- cotransporter, NBCe1) in β cells contributes to β cell functional decline in T2DM. As this NBCe1 protein is inappropriately activated in T2D and should elicit changes of intracellular buffering and intracellular pH (pHi) regulation, this Supplement training vehicle seeks to directly measure pHi in β cells that have NBCe1 knocked out or overexpressed. This work should not only reveal the metabolic state of the β cells but also allow us to more directly determine if altered intracellular pH-regulation, intracellular buffering or some other aspect of NBCe1 physiology changes the β cell phenotype to a T2D-state. To address this hypothesis, we will focus on parts of the original Specific Aims 2 (cellular pH regulation with genetic gain-of-function tools) and 3 (utilize novel genetic loss-of-function animal models) to test therapeutic potential of inhibiting SLC4A4/NBCe1 expression/activity in β cells as means to attenuate β cell failure and improve overall glucose metabolism under diabetogenic conditions. From Specific Aim 2, INS1 cells with a genetically encoded pH-sensor will be evaluated with and without NBCe1 genetic gain-of-function to document pH-changes and determine if pHi changes per se leads to β cell functional failure through impairment of mitochondrial metabolism and function. Similarly for Specific Aim 3, novel genetic loss-of-function animal models (NBCe1-loss in β cells) will be crosses with a novel pH-sensor mouse to determine pH and buffering of β cells within intact pancreatic islets. The current project will uncover novel molecular/physiological mechanisms underlying induction of β cell dysfunction and test a potentially novel therapeutic strategy to attenuate of β cell failure in T2DM. Parent PROJECT SUMMARY/ABSTRACT Type 2 diabetes mellitus (T2DM) manifests through the development of fasting and postprandial hyperglycemia the etiology of which can be distilled to failure of pancreatic β cells to maintain appropriate glucose-stimulated insulin secretion (i.e. β cell function) to compensate for the decline in insulin action (i.e. insulin resistance). Thus preservation of β cell function has been identified as a critical barrier for the development of successful preventative and treatment strategies to combat the rise in T2DM prevalence. Studies suggest that β cell dysfunction in T2DM is associated with metabolic reprogramming/shift toward increased non-oxidative glucose metabolism and reduced mitochondrial function similar to an adaptive features observed in cancer cells. Accordingly, cancer cells facilitate increased glycolytic flux and subsequent rise in metabolic acid production by upregulating expression of ion pumps/transporters that enhance cellular buffering capacity and promote cellular alkalinization (increased pHi), such as SLC4 family of bicarbonate transporters. Although, previous studies have confirmed importance of pHi for proper β cell functionality, it is unknown whether intracellular alkalinization or increased pHi buffering contributes to β cell functional decline in T2DM. Thus, the key objective of the current proposal is to test the hypothesis that aberrant induction of a novel T2DM gene SLC4A4 and its protein product (electrogenic Na+ -coupled HCO3- cotransporter, NBCe1) in β cells contributes to β cell functional decline in T2DM. To address this hypothesis, Specific Aim 1 will 1) perform detailed examination of SLC4A4/NBCe1 expression using our unique collection of autopsy-derived human pancreas from patients with obesity, pre-diabetes and T2DM and 2) elucidate molecular mechanisms mediating aberrant β cell induction of SLC4A4/NBCe1 in response to diabetogenic stressors. Specific Aim 2 will utilize novel genetic gain-of-function tools to test the hypothesis that intracellular alkalinization mediated by increased β cell expression of SLC4A4/NBCe1 leads to β cell functional failure through impairment of mitochondrial metabolism and function. Finally, Specific aim 3 will utilize novel genetic loss-of-function animal models and T2DM human islets to test therapeutic potential of inhibiting SLC4A4/NBCe1 expression/activity in β cells as means to attenuate β cell failure and improve overall glucose metabolism under diabetogenic conditions. The current project will uncover novel molecular/physiological mechanisms underlying induction of β cell dysfunction and test a potentially novel therapeutic strategy to attenuate of β cell failure in T2DM.

DEI 补充 R01-DK128844：补充摘要 2 型糖尿病 (T2DM) 通过空腹和餐后高血糖的发展表现出来 其病因可归结为胰腺β细胞无法维持适当的葡萄糖刺激 胰岛素分泌（即β细胞功能）以补偿胰岛素作用的下降（即胰岛素抵抗）。 我们正在进行的部分研究表明，SLC4A4 及其蛋白质产物（生电 Na+ 耦合 β 细胞中的 HCO3- 协同转运蛋白 (NBCe1) 会导致 T2DM 中的 β 细胞功能下降。 在 T2D 中被不适当地激活，应引起细胞内缓冲和细胞内 pH (pHi) 的变化 监管，这种补充训练工具旨在直接测量 NBCe1 被敲除的 β 细胞中的 pHi 这项工作不仅应该揭示β细胞的代谢状态，还可以让我们能够 更直接地确定细胞内 pH 调节、细胞内缓冲或其他一些方面是否发生改变 NBCe1 生理学将 β 细胞表型改变为 T2D 状态。 为了解决这个假设，我们将重点关注最初的特定目标 2 的部分内容（细胞 pH 值调节 遗传功能获得工具）和 3（利用新型遗传功能丧失动物模型）来测试治疗 抑制 β 细胞中 SLC4A4/NBCe1 表达/活性作为减轻 β 细胞衰竭的手段的潜力 根据特定目标 2，INS1 细胞可改善糖尿病条件下的整体葡萄糖代谢。 基因编码的 pH 传感器将在有或没有 NBCe1 遗传功能增益的情况下进行评估，以记录 pH 变化并确定 pHi 变化本身是否会通过损害 β 细胞功能而导致 线粒体代谢和功能与特定目标 3（新型遗传功能丧失动物）类似。 模型（β 细胞中 NBCe1 丢失）将与新型 pH 传感器小鼠杂交，以确定 pH 值和缓冲 完整胰岛内的β细胞当前的项目将揭示新的分子/生理学。 诱导 β 细胞功能障碍的机制并测试一种潜在的新颖治疗策略 减轻 T2DM 中的 β 细胞衰竭。 父项目摘要/摘要 2 型糖尿病 (T2DM) 通过空腹和餐后高血糖的发展表现出来 其病因可归结为胰腺β细胞无法维持适当的葡萄糖刺激 胰岛素分泌（即β细胞功能）以补偿胰岛素作用的下降（即胰岛素抵抗）。 因此，β细胞功能的保存已被确定为成功开发的关键障碍 对抗 T2DM 患病率上升的预防和治疗策略 研究表明，β 细胞。 T2DM 的功能障碍与代谢重编程/向非氧化葡萄糖增加的转变有关 新陈代谢和线粒体功能降低，类似于在癌细胞中观察到的适应性特征。 因此，癌细胞通过以下方式促进糖酵解通量增加以及随后代谢酸产生的增加 上调离子泵/转运蛋白的表达，增强细胞缓冲能力并促进 细胞碱化（pHi 增加），例如 SLC4 碳酸氢盐转运蛋白家族。 研究已证实 pHi 对于正常 β 细胞功能的重要性，但尚不清楚细胞内是否 碱化或 pHi 缓冲增加会导致 T2DM 中 β 细胞功能下降。 当前提案的目的是检验以下假设：新型 T2DM 基因的异常诱导 SLC4A4 及其蛋白质产物（生电 Na+ 偶联 HCO3- 协同转运蛋白，NBCe1）在 β 细胞中发挥作用 为了解决这一假设，具体目标 1 将 1) 进行详细说明。 使用我们独特的尸检来源的人类胰腺收集品检查 SLC4A4/NBCe1 表达 来自肥胖、糖尿病前期和 T2DM 患者，2) 阐明介导异常的分子机制 SLC4A4/NBCe1 的 β 细胞诱导响应糖尿病应激源将利用新的特定目标 2。 遗传功能获得工具来检验细胞内碱化是由 β 细胞增加介导的假设 SLC4A4/NBCe1 的表达通过线粒体代谢受损导致 β 细胞功能衰竭 最后，具体目标 3 将利用新型遗传功能丧失动物模型和 T2DM 人类。 胰岛测试抑制 β 细胞中 SLC4A4/NBCe1 表达/活性的治疗潜力 减轻 β 细胞衰竭并改善当前糖尿病条件下的整体葡萄糖代谢。 该项目将揭示诱导 β 细胞功能障碍的新分子/生理机制 测试一种潜在的新颖治疗策略，以减轻 T2DM 中 β 细胞衰竭。