Dual role of BAD in insulin secretion and beta cell survival

BAD 在胰岛素分泌和 β 细胞存活中的双重作用

基本信息

批准号：
9902406
负责人：
Nika N Danial
金额：
$ 41.79万
依托单位：
DANA-FARBER CANCER INST
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-04-01 至 2023-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9902406
关键词：
Active Sites Address BCL2 gene BH3 Domain Bad protein Beta Cell Binding Biochemical Cell Survival Cell physiology Cells Cellular Stress Cessation of life Cytoprotection Data Diabetes Mellitus Diabetic mouse Engraftment Enzyme Activation Enzyme Stability Enzymes Functional disorder Genetic Glucokinase Glucose Goals Grant Impairment In Vitro Individual Inflammatory Insulin Kinetics Maps Measures Mediating Metabolic Metabolic Control Mitochondria Molecular Mutation Outcome Oxidative Stress Pathway interactions Pharmacology Phosphorylation Property Protein Family Proteins Pyruvate Pyruvate Carboxylase Regulation Resistance Role Signal Transduction Stimulus Stress Structure of beta Cell of islet Structure of molecular layer of cerebellar cortex System Testing Translating Transplantation base biological adaptation to stress defined contribution diabetes mellitus therapy effective therapy functional restoration glucose metabolism improved improved functioning insight insulin secretion islet loss of function maturity onset diabetes of the young mimetics mimicry mitochondrial metabolism mutant oxidation preservation protective effect public health relevance pyruvate dehydrogenase response restoration stem

项目摘要

DESCRIPTION (provided by applicant): Glucose metabolism is central to regulation of β-cell function and survival. We have found that phosphorylation of the BCL-2 family protein BAD within its helical BH3 domain imparts cell autonomous protective effects to β-cells. The benefits of genetic and pharmacologic strategies that mimic the phospho-BAD BH3 helix include resistance to death induced by inflammatory and oxidative stress, as well as increased glucose handling and insulin secretory capacities. In the long-term, these benefits manifest in superior engraftment of donor islets in transplanted diabetic mice and an attendant increase in functional β-cell mass. The β-cell protective effect of phospho-BAD is dependent on the glucose-metabolizing enzyme glucokinase (GK), and is mediated by direct binding and activation of this enzyme by the phospho-BAD BH3 helix. Our proposed studies address a key question that stems from these findings: How is the β-cell sparing effect of phospho-BAD mediated by GK-dependent glucose metabolism? We will address this question at two highly integrative molecular layers. First, using metabolic flux analyses we will identify phospho-BAD dependent changes in mitochondrial metabolism of glucose-derived pyruvate at the level of pyruvate dehydrogenase (PDH) and pyruvate carboxylase (PC) pathway fluxes as β-cells are subjected to defined stress stimuli, and define their contribution to phospho-BAD's capacity to shield β-cells from stress-induced dysfunction and death (aim 1). Second, we will interrogate a defined number of MODY-derived GK mutants for their in vitro properties as well as their effect on β-cell survival in the presence of phospho-BAD (aim 2). These mutants, which are selected for their proximity near the binding interface of the BAD BH3 helix on GK, will reveal additional molecular aspects of GK regulation by phospho-BAD mimicry and provide a complementary experimental system to examine the effect of GK-dependent glucose metabolism on the β-cell protective effect of BAD phosphorylation. These studies will provide an integrated picture of the pathway connecting phospho-BAD-dependent GK activation and β-cell resistance to stress-induced dysfunction and death. In the fullness of time, understanding this pathway will yield valuable translational insights into the most effective strategies to capture and mimic the protective aspects of glucose signaling for preservation/restoration of functional β-cell mass.

描述（由适用提供）：葡萄糖代谢对于调节β细胞功能和存活至关重要。我们发现，Bcl-2家族蛋白在其螺旋BH3结构域中不良的磷酸化赋予细胞自主保护作用对β细胞。模仿磷酸化BH3螺旋的遗传和药物策略的益处包括炎症和氧化应激引起的死亡的抵抗，以及增加的葡萄糖处理和胰岛素分泌能力。从长远来看，这些益处在移植的糖尿病小鼠中的供体胰岛的超级移植中表现出来，功能性β细胞质量的增加。磷酸-BAD的β细胞保护作用取决于葡萄糖 - 代谢酶（GK），并通过磷酸-BAD BH3螺旋直接结合和激活该酶来介导。我们提出的研究提出了一个关键问题，即从这些发现中得出的步骤：磷酸-BAD的β细胞支撑效应如何由GK依赖性葡萄糖代谢介导？我们将在两个高度整合的分子层上解决这个问题。首先，使用代谢通量分析，我们将确定在丙酮酸脱氢酶（PDH）水平上葡萄糖衍生的丙酮酸线粒体代谢的磷酸 - 巴德依赖性变化，丙酮酸羧化酶羧化酶（PC）途径的β-频率刺激了型号，并赋予其定义的刺激范围，并适用于跨度的能力。压力引起的功能障碍和死亡（AIM 1）。其次，我们将询问定义的Mody衍生的GK突变体的体外特性，并在存在磷酸化的情况下对它们对β细胞存活的影响（AIM 2）。这些突变体因其在GK上不良BH3螺旋的结合界面附近而被选为其接近性，这将揭示通过磷酸化 - 巴德模拟物的GK调控的其他分子方面，并提供了一个完整的实验系统，以研究GK依赖性葡萄糖代谢对β-细胞受害phopphosphosphosperlation的影响的效果。这些研究将提供连接磷酸-BAD-BAD依赖性GK激活以及β细胞耐药性的途径的综合图像。在时间的填补度中，理解这一途径将产生有价值的翻译见解，以捕获和模仿葡萄糖信号的受保护方面，以保存/恢复功能性β细胞质量。