DYNORPHIN AND BETA CELL SENSITIZATION

强啡肽和 β 细胞致敏

• 批准号: 2794817
• 负责人: MARVIN C GERSHENGORN
• 金额: $ 16.93万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-30 至 2000-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2794817
• 关键词: NMDA receptors; biological signal transduction; calcium flux; dynorphins; glucose; pancreatic islet function; receptor binding; receptor expression; tissue /cell culture; transfection

In this project, the PI proposes a series of experiments to determine whether dynorphin and related peptides, acting through a mechanism independent of the protein-coupled opioid receptors, synergize with glucose to stimulate insulin secretion from beta cells of the pancreatic islets of Langerhans. The following hypothesis will be tested. Dynorphin sensitizes beta cells to glucose-induced insulin secretion by activating (or prolonging the activation of) N-methyl-D-aspartate (NMDA)-selective excitatory ionotropic glutamate receptors. Dynorphin A is a member of the family of opioid peptides that appear to act primarily as neuromodulators by interacting with G protein-coupled receptors (GPCRs); mu and kappa and NMDA receptors are members of a class of ligand-gated ion channels that when activated increase the permeability of the cell surface membrane to Ca2+ (and Na+ and K+) and thereby elevate cytoplasmic free Ca 2+ concentration. Elevations in cytoplasmic free C2+ will in turn sensitize the cell to stimulation by glucose and couple stimulation to insulin secretion. The Specific Aims that will be pursued are: 1) To determine whether dynorphin and related peptides synergize with glucose stimulation of insulin secretion by signaling via NMDA receptors. The PI will employ a mouse insulinoma cell line, MIN6 to study binding and signaling characteristics of endogenously expressed NMDA receptors in insulin- secreting cells and compare those findings with observations made in human embryonic kidney cells (HEK 293 cells) and monkey kidney COS-1 cells expressing NMDA receptors comprised of specific subunits by gene transfer. 2) To determine which subunits form dynorphin-binding NMDA receptors so as to begin to delineate the domain(s) on the subunit(s) that directly bind dynorphin and related peptides. The experiments involving expression of NMDA receptor subunits will be performed in transfected HEK 293 cells and COS-1 cells in which the receptors can be expressed to high levels. 3) To determine the pharmacophore within the dynorphin peptide. That is, to determine the smallest peptide that retains the NMDA receptor-binding and insulin secretagogue characteristics of Dyn A(1-17). These experiments will be performed in MIN6, HEK 293 and COS-1 cells. If the dynorphin-NMDA receptor-calcium pathway were shown to sensitize beta cells to glucose-induced insulin secretion, a long-term goal of this research will be to develop nonpeptidic, orally active drugs that can be used to treat diabetes mellitus in humans.

在这个项目中，PI提出了一系列实验来确定 Dynorphin和相关肽是否通过机制作用 独立于蛋白质偶联的阿片类药物受体，与 葡萄糖从胰腺的β细胞刺激胰岛素分泌 Langerhans的胰岛。 将检验以下假设。 Dynorphin通过 激活（或延长激活）N-甲基-D-天冬氨酸 （NMDA）选择性兴奋性离子型谷氨酸受体。 Dynorphin A是似乎行动的阿片类肽家族的成员 主要通过与G蛋白耦合相互作用作为神经调节剂 受体（GPCR）; MU和Kappa和NMDA受体是 当激活时，配体门控离子通道会增加 细胞表面膜对Ca2+（以及Na+和K+）的渗透性，并且 从而提高细胞质游离Ca 2+浓度。 高程 胞质游离C2+将依次使细胞刺激刺激 葡萄糖和夫妇刺激胰岛素分泌。 将要追求的具体目标是：1）确定是否是否 Dynorphin和相关肽与葡萄糖刺激协同作用 通过NMDA受体信号传导的胰岛素分泌。 PI将雇用 小鼠胰岛素瘤细胞系，MIN6来研究结合和信号传导 胰岛素中内源表达的NMDA受体的特征 分泌细胞并将这些发现与观察结果进行比较 人类胚胎肾细胞（HEK 293细胞）和猴肾Cos-1 表达由基因特定亚基组成的NMDA受体的细胞 转移。 2）确定哪些亚基形成dynorphin结合NMDA 受体开始在亚基上描绘域 直接结合驱指肽和相关肽。 实验 涉及NMDA受体亚基的表达将在 转染HEK 293个细胞和COS-1细胞，其中受体可以是 表示高水平。 3）确定在 dynorphin肽。 也就是说，确定最小的肽 保留NMDA受体结合和胰岛素秘密 Dyn A（1-17）的特征。这些实验将在 MIN6，HEK 293和COS-1细胞。 如果Dynorphin-NMDA受体 - 钙 显示途径可以使β细胞对葡萄糖诱导的胰岛素敏感 分泌，这项研究的长期目标是发展 可用于治疗糖尿病的非肽，口服活性药物 人类中的梅利图斯。