Beta-Cell Compensation In Partial Pancreatectomy Mice

部分胰腺切除小鼠的β细胞补偿

基本信息

批准号：
8514582
负责人：
John L. Leahy
金额：
$ 30.12万
依托单位：
UNIVERSITY OF VERMONT & ST AGRIC COLLEGE
依托单位国家：
美国
项目类别：
财政年份：
2000
资助国家：
美国
起止时间：
2000-02-15 至 2014-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8514582
关键词：
Agonist Anabolism Animal Model Animals Beta Cell Binding Binding Sites Biochemical Biochemistry Cell Culture Techniques Cell Survival Cell physiology Cells Cellular biology Complex Data Diabetes Mellitus Elements Equilibrium Event Experimental Models Financial compensation Functional disorder Funding GNAI2 gene Gene Targeting Genes Genetic Transcription Glucose Goals Health Hepatocyte Human Hyperglycemia Imaging Techniques Immunoblotting In Vitro Indium Insulin Insulin Resistance Insulin-Dependent Diabetes Mellitus Islet Cell Knock-out Knockout Mice Laboratories Link Maintenance Mediating Metabolic Metabolism Mitochondria Molecular Molecular and Cellular Biology Mus Mutate Nature Non-Insulin-Dependent Diabetes Mellitus Nuclear Obesity Pancreas Pancreatectomy Pathway interactions Pattern Peroxisome Proliferator-Activated Receptors Physiology Predisposing Factor Principal Investigator Process Pyruvate Carboxylase Rattus Regulation Regulatory Element Regulatory Pathway Resistance Response Elements Rodent Role Signal Pathway Signal Transduction System Testing Transcriptional Regulation Transgenes Universities Vermont Zucker Rats base blood glucose regulation computerized data processing forkhead protein gastric inhibitory polypeptide receptor glucagon-like peptide 1 improved in vivo insulin secretion insulin sensitivity islet prevent promoter response stem troglitazone

项目摘要

DESCRIPTION (provided by applicant): The islet ¿-cell is the key regulatory element of the glucose homeostasis system. Changes in insulin sensitivity and/or ¿-cell mass elicit precise adaptations from the remaining ¿-cells so normoglycemia is maintained. How is that accomplished? What signaling pathways and ¿-cell molecular processes are involved? This application continues our studies of the ¿-cell adaptive mechanisms to a reduction in ¿-cell mass such as occurs in evolving type 1 diabetes, likely also type 2 diabetes, using the experimental model of 60% pancreatectomy (Px) in normally insulin sensitive rodents. These rodents are normoglycemic following the reduction in ¿-cell mass because of a multifacted adaptive response in islet ¿-cells that results in maintenance of a normal level of secreted insulin. We plan to test a well-defined mechanistic schema for the adaptive responses based on findings from the prior funding period. Specifically, we propose an essential role for PPAR? by way of its transcriptional regulation of key genes that impact ¿-cell function and survival (pdx-1), the incretin system (GIP receptor), and mitochondrial fuel metabolism (pyruvate carboxylase). Also, we propose upstream transcriptional regulation of PPAR? by the forkhead transcription factor FoxO1. Finally, we propose disruption of this signaling system is responsible for features of the ¿-cell dysfunction in animals and humans with type 2 diabetes. We will test these hypotheses in mice with genetically altered expression of key elements in the proposed signaling pathways - pancreas specific PPAR? knockout, whole animal heterozygous FoxO1, and constitutively nuclear FoxO1 in ¿-cells and liver - that undergo 60% Px or treatment with pharmacologic activators of the proposed signaling pathway. Parallel in vitro studies will be performed in mouse and human islets and INS-1 cells. Aim #1 will test the hypothesis of a necessary role for PPAR? in the enhanced ¿-cell function post-Px using pancreas-specific PPAR? null mice, and confirm PPAR? regulates the same target genes in human islets. Aim #2 will define the molecular interaction between FoxO1 and PPAR? in vitro, confirm the same regulation occurs in human islets, and compare expression of PPAR?-regulated genes and ¿-cell function following Akt activators (GLP-1 and insulin) and 60% Px in wild type and mutated FoxO1 mice. Aim #3 will use in vitro and in vivo studies to confirm that hyperglycemia impairs ¿-cell PPAR? signaling and consequently expression of its downstream regulated genes, and investigate strategies to restore PPAR? expression in order to improve hyperglycemia-induced ¿-cell dysfunction. PUBLIC HEALTH RELEVANCE: The islet ¿-cell regulates the storage and metabolism of cellular fuels through its secretion of insulin. Not surprisingly, the regulatory systems governing insulin secretion and biosynthesis, and the ¿-cell mass, are complex. The best-studied factor is glucose; in reality, the primary action of ¿-cells is to maintain the normal metabolic milieu. When functioning normally, an altered insulin sensitivity or ¿-cell mass is balanced by precise compensatory changes in insulin secretion (so called ¿-cell adaptation) so glucose homeostasis is maintained. Thus, the normal system of glucose homeostasis is based on ¿-cell adaptive mechanisms that entail molecular and signaling processes that are not dependent on sustained changes in glycemia. Surprisingly little is known about this fundamental feature of how ¿-cells function. The overall goal of our studies is to identify the ¿-cell biochemical, molecular and functional events that underlie this adaptation. Our laboratory has taken the approach of studying rodents with successful ¿-cell adaptation to a lowered ¿-cell mass or insulin resistance as defined by normoglycemia. This application continues our studies of the ¿-cell adaptive mechanisms to a reduction in ¿-cell mass as occurs in evolving type 1 diabetes, also likely type 2 diabetes, using the experimental model of 60% pancreatectomy (Px). We now propose to test a well-defined mechanistic schema based on our findings from the prior funding period, by performing Px studies in mice with genetically altered expression of key elements of the proposed regulatory pathway. Specifically, we propose an essential role for hyperexpression of ¿-cell PPAR? to upregulate transcription of key genes for ¿-cell function and survival (pdx-1), the incretin system (GIP receptor), and mitochondrial fuel metabolism (pyruvate carboxylase). Also, we propose deactivation of the FoxO1 inhibitory upstream regulation of PPAR? transcription is the mechanism for the PPAR? hyperexpression. Finally, we pro- pose that disruption of this signaling system is responsible for features of the ¿-cell dysfunction in animal and human type 2 diabetes. We will test these hypotheses in mice with genetically altered expression of key elements in the proposed signaling pathways - pancreas specific PPAR? knockout, whole animal hetero- zygous FoxO1, and constitutively nuclear FoxO1 in ¿-cells and liver - that undergo 60% Px or treatment with pharmacologic activators of the proposed signaling pathway. Parallel in vitro studies will be performed in mouse and human islets and INS-1 cells. A notable feature is the interdisciplinary nature of the studies because of the complimentary expertise of the principal investigator Jack Leahy (¿-cell biochemistry, physiology, in vivo animal models) with Tom Jetton (imaging techniques to study islet cell biology) and Mina Peshavaria (molecular and cellular biology of the ¿-cell) at the University of Vermont.

描述（由应用程序提供）：胰岛 - 细胞是葡萄糖稳态系统的关键调节元素。胰岛素敏感性的变化和/或 - 细胞质量引起其余的细胞的精确适应性，因此可以保持正常血糖。那是如何成就的？涉及哪些信号通路和 - 细胞分子过程？该应用程序继续我们的研究 - 细胞自适应机制减少了 - 细胞质量，例如在不断发展的1型糖尿病中发生，也可能使用正常胰岛素敏感啮齿动物的60％胰腺切除术（PX）的实验模型。由于胰岛细胞中多因素的适应性反应，这些啮齿动物的质量降低后，这些啮齿动物是正常的，这会导致维持正常的分泌胰岛素水平。我们计划根据以前的资金期间的发现来测试定义明确的机械架构，以对自适应响应进行自适应响应。具体来说，我们提出了PPAR的重要作用？通过其转录调节影响 - 细胞功能和生存的关键基因（PDX -1），增加素系统（GIP受体）和线粒体燃料代谢（丙酮酸羧化酶）。另外，我们提出了PPAR上游的转录调控？由叉子转录因子foxo1。最后，我们提出这种信号系统的破坏是导致2型糖尿病动物和人类中电池功能障碍的特征。我们将在提出的信号传导途径中的关键元素（胰腺特异性PPAR）中的关键元素表达的大致改变的小鼠中测试这些假设？敲除，整个动物杂合FOXO1和组成性的核FOXO1在`` - 细胞和肝脏）进行了60％的PX或使用所提出的信号传导途径的药物激活剂进行治疗。在小鼠和人类胰岛和INS-1细胞中将进行平行的体外研究。 AIM＃1将检验PPAR必要角色的假设？在增强的�-cell函数中，PX使用胰腺特异性PPAR？无效的小鼠，并确认PPAR？调节人类胰岛中相同的靶基因。 AIM＃2将定义FOXO1和PPAR之间的分子相互作用？在体外，确认相同的调节发生在人类胰岛中，并比较了Akt激活剂（GLP-1和胰岛素）和60％PX在野生型和突变的FOXO1小鼠中比较PPAR？调节基因和`` - 细胞功能。 AIM＃3是否会在体外和体内研究中确认高血糖会损害-CELL PPAR？信号传导和其下游调节基因的表达，并研究恢复PPAR的策略？为了改善高血糖诱导的 - 细胞功能障碍。公共卫生相关性：胰岛�-细胞通过其胰岛素的分泌来调节细胞燃料的储存和代谢。毫不奇怪，控制胰岛素分泌和生物合成的调节系统以及–细胞质量是复杂的。最佳研究因素是葡萄糖。实际上，``````''的主要动作是维持正常的代谢环境。正常运作时，通过胰岛素分泌的精确代偿性变化（所谓的 - 细胞适应性）可以平衡胰岛素敏感性或细胞质量，从而维持葡萄糖稳态。这就是葡萄糖稳态的正常系统基于````````cel）自适应机制了，这些机制需要分子和信号传导过程，这些机制不依赖于血糖的持续变化。令人惊讶的是，对于�Cells功能的这一基本特征知之甚少。我们研究的总体目的是确定基于这种适应的细胞生化，分子和功能事件。我们的实验室采取了成功研究啮齿动物的方法。循环`` - 细胞适应降低的细胞质量或胰岛素耐药性''的方法。该应用程序继续我们对使用60％胰腺切除术（PX）的实验模型，继续我们对细胞自适应机制的研究，以减少–细胞质量降低–细胞质量。现在，我们建议根据先前资助期的发现来测试定义明确的机械架构，通过在小鼠中进行PX研究，并在拟议的调节途径的关键元素的表达中有很大变化。具体而言，我们提出了`` - cell ppar''的至关重要的作用吗？为了上调关键基因的转录 - 细胞功能和生存（PDX -1），增加素系统（GIP受体）和线粒体燃料代谢（丙酮酸羧化酶）。另外，我们提出了FOXO1抑制性上游调节PPAR的停用？转录是PPAR的机制？过度X级。最后，我们促进该信号系统的破坏是导致动物和人类2型糖尿病中细胞功能障碍的特征。我们将在提出的信号传导途径中的关键元素（胰腺特异性PPAR）中的关键元素表达的大致改变的小鼠中测试这些假设？敲除，整个动物异质FOXO1，以及循环和肝脏中的组成型核FOXO1，可通过提议的信号传导途径的药物激活剂进行60％的PX或治疗。在小鼠和人类胰岛和INS-1细胞中将进行平行的体外研究。一个值得注意的特征是研究的跨学科性质，因为主要研究者杰克·利希（Jack Leahy）的免费专业知识（�-cell生物化学，生理学，体内动物模型）具有汤顿（Inslet Cellogy of Islet Cell Biyology）和Mina Peshavaria（Mina Peshavaria（Mina Peshavaria）（分子和细胞生物学）（分子和细胞生物学的成像技术），