Regulation of beta cell identity and dedifferentiation

β细胞身份和去分化的调节

• 批准号: 9025789
• 负责人: Matthias Hebrok
• 金额: $ 39.95万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-01 至 2019-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9025789
• 关键词: Address; Affect; Animals; Back; Beta Cell; Boxing; Cell Differentiation process; Cell physiology; Cells; Complex; Data; Defect; Development; Diabetes Mellitus; Disease; Exposure to; Flowcharts; Functional disorder; Gene Activation; Gene Expression; Gene Targeting; Genes; Genetic; Glucose; Glucose Intolerance; Glycolysis; Goals; Gray unit of radiation dose; Health; Human; Individual; Insulin; Insulin Resistance; Islet Cell; Lead; Maintenance; Metabolic; Metabolic stress; Metabolism; Modeling; Molecular; Non-Insulin-Dependent Diabetes Mellitus; Obesity; Oranges; Outcome; Oxidative Phosphorylation; Pancreas; Pathway interactions; Patients; Peripheral; Phenotype; Play; Population; Protocols documentation; Regulation; Reporting; Risk Factors; Rodent Model; Role; Sampling; Signal Pathway; Structure of beta Cell of islet; Testing; Therapeutic; Transgenic Animals; Transgenic Mice; Transgenic Organisms; Translating; VHL gene; base; blood glucose regulation; cell dedifferentiation; combinatorial; comparative; design; diabetic; diabetic patient; genetic manipulation; genetic regulatory protein; genome wide association study; human embryonic stem cell; human stem cells; islet; mouse model; mutant; novel; novel therapeutics; overexpression; pandemic disease; prevent; research study; stressor; tool; transcription factor

 DESCRIPTION (provided by applicant): Type II Diabetes (T2D) is a debilitating disease that afflicts an ever-growing population throughout the world. In addition to obesity and insulin resistance contributing towards the development of the disease, beta cell dysfunction is increasingly implicated in promoting T2D. The reduction or loss of beta cell function due to a shift in the cellular state has reemerged as a contributor to disease. The mature state of the beta cell can be perturbed due to exposure to distinct stressors, and this results in loss of cellular identity or "de-differentiation". Numerous studies in rodent models have recently reported the occurrence of beta cell de-differentiation that then leads to diabetes. Significantly, T2D patient samples also have been reported to have a perturbation in the expression of key factors that are required for the maintenance of a fully functional beta cell. Identifying mechanisms that perturb the beta cell state that then contributes to the loss of glucose homeostasis is the overarching goal of this proposal. Complex mouse models that regulate gene expression in beta cells provide preliminary evidence of a modified beta cell "identity", i.e. a loss of canonical beta cell genes and activation of genes normally absent from a fully functional beta cell. In two mouse models (depletion of the von Hippel Lindau (VHL) gene and activation of the Sox9 transcription factor), erroneous activation of signaling pathways leads to beta cell de-differentiation and diabetes. Probing these transgenic tools allows for further exploration of the components downstream of these regulatory proteins that impact beta cell fate and function. The experiments outlined in this proposal focus on characterizing changes that occur in the pancreatic beta cells in both these mouse models, and validating the results in beta cells that we can now successfully generate from human embryonic stem cells (hESCs) using directed differentiation protocols. We have already conducted preliminary experiments and obtained data to support the hypothesis that novel factors dysregulated in ß-cells of the mutant animals can perturb beta cell identity and consequently function when expressed erroneously. In addition, we have generated a third model in which we observe ß-cell dysfunction caused by changes in the metabolic state of the cell, independent of de-differentiation defects. Thus, we have models in place to dissect different modulators of ß-cell dysfunction. State of the art combinatorial approaches combining the use of transgenic animals, hESC derived ß-cells, and human islets and ß-cells, will be employed to characterize the function of these factors in ß-cell dedifferentiation, metabolic defects, and dysfunction. Candidate factors will be tested for erroneous expression in samples isolated from T2D patients provided by nPOD. The overarching goal of these studies is to identify novel disruptors of ß-cell function whose activity could be modulated with the intent of preventing or reversing the compromised beta cell state back to a fully functional one in human patients.

 描述（由申请人提供）：II 型糖尿病 (T2D) 是一种使人衰弱的疾病，困扰着全世界不断增长的人口。除了肥胖和胰岛素抵抗导致该疾病的发展之外，β 细胞功能障碍也越来越多地与 T2D 的发生有关。由于细胞状态的转变而导致的β细胞功能的减少或丧失已重新成为疾病的诱因。由于暴露于不同的应激源，β细胞的成熟状态可能会受到干扰，这会导致细胞身份的丧失或“去分化”。最近对啮齿动物模型的大量研究报告了β细胞去分化的发生，从而导致糖尿病。显著地， 据报道，T2D 患者样本中维持完整功能的 β 细胞所需的关键因子的表达存在扰动。该提案的首要目标是确定扰乱β细胞状态从而导致葡萄糖稳态丧失的机制。调节β细胞基因表达的复杂小鼠模型提供了修饰β细胞“身份”的初步证据，即 典型 β 细胞基因的丢失和功能齐全的 β 细胞通常不存在的基因的激活。在两种小鼠模型中（von Hippel Lindau (VHL) 基因的缺失和 Sox9 转录因子的激活），信号通路的错误激活会导致 β 细胞去分化和糖尿病。探索这些转基因工具可以进一步探索这些调节蛋白下游影响β细胞命运和功能的成分。该提案中概述的实验重点是表征这两种小鼠模型中胰腺β细胞中发生的变化，并验证我们现在可以使用定向分化方案从人胚胎干细胞（hESC）成功生成的β细胞中的结果。我们已经进行了初步实验并获得了数据来支持这样的假设：突变动物的β细胞中失调的新因子可以扰乱β细胞的身份，从而在错误表达时发挥作用。此外，我们还生成了第三个模型，在该模型中我们观察到由细胞代谢状态变化引起的 β 细胞功能障碍，与去分化缺陷无关。因此，我们有适当的模型来剖析 β 细胞功能障碍的不同调节剂。最先进的组合方法结合使用转基因动物、hESC 衍生的 β 细胞以及人胰岛和 β 细胞，将用于表征这些因子在 β 细胞去分化、代谢缺陷和功能障碍中的功能。将测试从 nPOD 提供的 T2D 患者分离的样本中候选因子的错误表达。这些研究的首要目标是确定β细胞功能的新型破坏者，其活性可以被调节，以防止或逆转人类患者受损的β细胞状态回到功能齐全的状态。