Regulation of Vascular BK Channel in Diabetes

糖尿病中血管 BK 通道的调节

• 批准号: 8468725
• 负责人: Hon-Chi Lee
• 金额: $ 35.6万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2014-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8468725
• 关键词: Animals; Antioxidants; Arachidonic Acids; Blood Vessels; Blood flow; Calcium; Cardiovascular Diseases; Cardiovascular system; Cells; Coronary; Coronary artery; Cysteine; Cytochrome P450; Diabetes Mellitus; Diabetic mouse; Disease; Endothelium; Enzymes; Epidemic; Functional disorder; Funding; Gene Transfer; Glucose; Goals; Health; Human; Hydrogen Peroxide; Hyperglycemia; In Vitro; Ion Channel; Knock-out; Mediating; Molecular; Morbidity - disease rate; Muscle function; Mutation; Non-Insulin-Dependent Diabetes Mellitus; Organ; Oxidants; Oxidation-Reduction; Oxidative Stress; Patch-Clamp Techniques; Potassium; Prevention; Production; Property; Proteins; Reactive Oxygen Species; Regulation; Research; Role; Smooth Muscle Myocytes; Superoxide Dismutase; System; Testing; Transgenic Mice; Ubiquitin; Ubiquitination; Vascular Endothelial Cell; Vasodilation; catalase; diabetic; diabetic patient; diabetic rat; in vivo Model; insight; large-conductance calcium-activated potassium channels; mortality; multicatalytic endopeptidase complex; novel; overexpression; programs; research study; voltage

DESCRIPTION (provided by applicant): The large conductance calcium-activated potassium (BK) channels are major ionic determinants in mediating vasorelaxation and are the target of endothelium-derived hyperpolarizing factors (EDHFs). We found that regulation of BK channels by EDHFs is abnormal in diabetic animals and the intrinsic properties of BK channels are altered in diabetic coronary arteries. The BK channels in coronary arterial smooth muscle cells from diabetic animals have reduced sensitivity to calcium- and voltage-dependent activation. We have demonstrated that the mechanism whereby vascular BK channel regulation is altered in Type 1 and Type II diabetes involves hyperglycemia-induced oxidative stress, where the cysteine residues in BK channels are targets of redox modulation. The C911 residue of the BK channel pore subunit is particularly sensitive to modulation by hyperglycemia and by hydrogen peroxide, as the C911A mutation is insensitive to the effects of hydrogen peroxide and to high glucose. The goal of this project is to further delineate the molecular mechanisms through which reactive oxygen species (ROS) modulate BK channels in diabetes. The hypotheses to be tested are: 1) Abnormal vascular BK channel function in diabetes is due to redox modulation of specific cysteine residues by ROS. 2) BK channel modified by ROS is a substrate for ubiquitination and proteasomal degradation. Three specific aims are proposed. Aim 1 will examine the mechanism of BK channel modulation by diabetes-induced oxidative stress. Aim 2 will examine whether prevention of oxidative modulation of specific cysteine residues would maintain the integrity of BK channel function in diabetes. Aim 3 will determine whether redox-modulated BK channels are targets for ubiquitination and proteasomal degradation. These studies will be performed using in vitro and in vivo models of diabetes. Whole-cell and single channel patch clamp techniques, antioxidant enzyme in vitro gene transfer, and specific transgenic mice will be employed to determine the effects of diabetes-induced ROS production on BK channel function and degradation. The results of this project may provide important novel insight into the electrophysiological and molecular mechanisms of altered BK channel function that may contribute to both endothelium-dependent and -independent vascular dysfunction in diabetes.

描述（由申请人提供）：大电导钙激活的钾（BK）通道是介导血管征的主要离子决定因素，并且是内皮衍生的超极化因子（EDHFS）的目标。我们发现，EDHFS对BK通道的调节在糖尿病动物中是异常的，并且在糖尿病冠状动脉中，BK通道的内在特性改变了。来自糖尿病动物的冠状动脉平滑肌细胞中的BK通道降低了对钙和电压依赖性激活的敏感性。我们已经证明，在1型和II型糖尿病中改变血管BK通道调节的机制涉及高血糖诱导的氧化应激，其中BK通道中的半胱氨酸残基是氧化还原调节的靶标。 BK通道孔亚基的C911残基对高血糖的调节和过氧化氢特别敏感，因为C911a突变对过氧化氢和高葡萄糖的影响不敏感。该项目的目的是进一步描述反应性氧（ROS）调节糖尿病中的BK通道的分子机制。要测试的假设是：1）糖尿病中异常血管BK通道功能是由于ROS对特定半胱氨酸残基的氧化还原调节所致。 2）ROS修饰的BK通道是用于泛素化和蛋白酶体降解的底物。提出了三个具体目标。 AIM 1将检查糖尿病诱导的氧化应激的BK通道调节机制。 AIM 2将检查预防特定半胱氨酸残基的氧化调节是否会保持糖尿病中BK通道功能的完整性。 AIM 3将确定氧化还原调节的BK通道是否是泛素化和蛋白酶体降解的靶标。这些研究将使用体外和体内糖尿病模型进行。全细胞和单通道斑块夹技术，体外基因转移的抗氧化酶以及特定的转基因小鼠将用于确定糖尿病诱导的ROS产生对BK通道功能和降解的影响。该项目的结果可能会为改变BK通道功能的电生理学和分子机制提供重要的新见解，这可能有助于糖尿病中内皮依赖性和非依赖性血管功能障碍。