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.

抽象的 分泌的颗粒保持低pH值，并且越来越多 认识到这种现象对分泌很重要。 cl-穿过颗粒 据认为，膜被认为是通过V-ATPase分流H+涌入的，从而防止 大型经晶膜电位的积累。我们已经显示了第一个 在胰腺β细胞中，氯化物通道（特别是CLC-3）在 胰岛素分泌，可能通过调节酸化。以前，我们已经表明 CAMKII门控氯化物通道Clc-3在功能上表达 含胰岛素颗粒的膜。孤立β细胞的功能研究 表明CLC-3的激活是胰岛素分泌允许的。至少在 部分，促进颗粒酸化；废除酸化的各种策略 以类似的方式破坏分泌。这些观察是新兴的一部分 关于分泌的水泡离子频道所扮演的重要作用的文献，以及 在几种情况下，囊泡酸化的更具体要求。最近，我们 已将我们的发现扩展到CLC-3基因敲除鼠标。我们认为camkii 调节胰腺β细胞中的CLC-3通道并控制颗粒 酸化，使颗粒分泌能力。我们使用的初步数据 CLC-3敲除小鼠表明β细胞在胞吐作用和突变体有缺陷 动物表现出异常的葡萄糖耐受性。本应用的目的是 确定这种现象对胰岛素分泌的重要性，了解其 机理并确定导致通道激活的门控过程。 目前的应用基于该基础，并建议在分子中解开 详细说明CLC-3氯化物通道在β细胞分泌中的作用。颗粒的酸化 除了帮助加工胰岛素的加工之外，可能在分泌物中发挥多种作用 前体，这可能被证明是密集核颗粒分泌的一般特征。在 除了在K（ATP）通道上作用并增加触发因素的可用药物外 信号，将纠正放大途径缺陷的新型药物将是 在糖尿病患者中恢复适当的胰岛素分泌方面有可能有用。