Chloride Channel Involvement in Diabetes

氯离子通道参与糖尿病

• 批准号: 7500433
• 负责人: DEBORAH J. NELSON
• 金额: $ 9.21万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-24 至 2008-09-23
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7500433
• 关键词: Acetylcholine; Adopted; Animals; Area; Beta Cell; Biological Assay; Cell physiology; Cell secretion; Cell surface; Cells; Chicago; Chloride Channels; ClC-3 channel; Code; Condition; Cytoplasmic Granules; Cytoplasmic Tail; Data; Defect; Diabetes Mellitus; Electric Capacitance; Exhibits; Exocytosis; Fasting; Fluorescence Microscopy; Foundations; Glucose; Glucose tolerance test; Goals; Hyperglycemia; Immunoprecipitation; In Vitro; Individual; Insulin; Intracellular Membranes; Ion Channel; Kinetics; Knock-out; Knockout Mice; Label; Lead; Lentivirus Infections; Life; Literature; Measurement; Mediating; Membrane; Membrane Potentials; Modeling; Modification; Molecular; Mus; Mutant Strains Mice; Numbers; Pathway interactions; Patients; Peptide antibodies; Perfusion; Personal Satisfaction; Pharmaceutical Preparations; Phenotype; Phosphorylation; Physiological; Plasma; Play; Primary Cell Cultures; Process; Protein Dephosphorylation; Protein Overexpression; Proteins; Regulation; Role; Role playing therapy; Secretory Vesicles; Shunt Device; Signal Transduction; Staging; Standards of Weights and Measures; Stimulus; Structure of beta Cell of islet; Subfamily lentivirinae; System; Testing; Thinking; Time; Transfection; Universities; Vesicle; abstracting; calmodulin-dependent protein kinase II; diabetic; glucose tolerance; in vivo; insulin granule; insulin secretion; islet; knock-down; mutant; novel; prevent; research study; response; restoration; small hairpin RNA; vacuolar H+-ATPase

Abstract Secretory granules maintain a low intragranular pH and it is becoming increasingly recognized that this phenomenon is important to secretion. Cl- entry across the granule membrane is thought to be required to shunt H+ influx via the V-ATPase, thus preventing the build-up of a large transgranular membrane potential. We have shown, for the first time in pancreatic beta cells, that chloride channels (specifically ClC-3) play a role in insulin secretion, likely through regulation of acidification. Previously, we have shown that the CaMKII-gated chloride channel, ClC-3, is functionally expressed in the membrane of insulin-containing granules. Functional studies in isolated beta-cells showed that activation of ClC-3 is permissive for insulin secretion. This is due, at least in part, to the promotion of granular acidification; various strategies to abolish acidification disrupt secretion in a similar manner. These observations are part of a burgeoning literature on the important role played by vesicular ion channels in secretion, as well as the more specific requirement for vesicle acidification in several cases. Recently, we have extended our findings to the ClC-3 knockout mouse. We posit that CaMKII regulates the ClC-3 channel in pancreatic beta-cells and controls granule acidification, rendering granules secretion-competent. Our preliminary data utilizing ClC-3 knock-out mice indicate that beta-cells are defective in exocytosis and the mutant animals exhibit aberrant glucose tolerance. The goal of the present application is to determine the importance of this phenomenon to insulin secretion, understand its mechanism and determine the gating processes that lead to activation of the channel. The present application builds on this foundation and proposes to unravel in molecular detail the role of ClC-3 chloride channels in beta-cell secretion. Acidification of granules may play multiple roles in secretion beyond aiding in the processing of insulin precursors, and it may prove to be a general feature of dense-core granule secretion. In addition to the available drugs that act on K(ATP) channels and increase the triggering signal, novel drugs that would correct a defect in the amplification pathway would be potentially useful in the restoration of adequate insulin secretion in diabetic patients.

摘要 分泌颗粒维持低的颗粒内pH，并且它变得越来越 认识到这种现象对分泌很重要。Cl-进入颗粒 膜被认为是需要通过V-ATP酶分流H+流入，从而防止 大的跨颗粒膜电位的建立。我们已经证明，对于第一个 在胰腺β细胞中，氯离子通道（特别是ClC-3）在 胰岛素分泌，可能通过调节酸化。此前，我们已经展示了 CaMKII门控氯离子通道，ClC-3，在功能上表达于 含胰岛素颗粒的膜。分离β细胞的功能研究 表明ClC-3的激活允许胰岛素分泌。这是由于，至少在 部分，以促进颗粒酸化;各种战略，以消除酸化 以类似的方式破坏分泌。这些观察是一个新兴的 关于囊泡离子通道在分泌中所起重要作用的文献，以及 在一些情况下，对囊泡酸化的更具体的要求。最近我们 将我们的发现扩展到了ClC-3基因敲除小鼠。我们把CaMKII 调节胰腺β细胞中的ClC-3通道并控制颗粒 酸化，使颗粒具有分泌能力。我们的初步数据利用 ClC-3敲除小鼠表明β细胞在胞吐作用中有缺陷，并且突变体 动物表现出异常的葡萄糖耐量。本申请的目的是 确定这种现象对胰岛素分泌的重要性，了解其 机制，并确定门控过程，导致激活的渠道。 本申请建立在此基础上，并提出了在分子水平上解开。 详细介绍了ClC-3氯离子通道在β细胞分泌中的作用。颗粒酸化 除了帮助胰岛素加工之外，还可能在分泌中发挥多种作用 前体，它可能被证明是致密核心颗粒分泌的一般特征。在 除了作用于K（ATP）通道并增加触发的可用药物外， 信号，新的药物，将纠正缺陷的扩增途径将是 潜在地可用于恢复糖尿病患者的足够胰岛素分泌。