CHRONIC ALCOHOL EXPOSURE AND CALCIUM SIGNALING

申请人摘要：已知乙醇暴露会干扰许多信号 转导途径，包括那些涉及腺苷酸环化酶和 磷酸肌醇周转 据推测，乙醇介导的 信号转导通路的改变可能反映了一种机制， 这些细胞适应并产生对乙醇急性作用的耐受性。 先前的研究已经确定，从酒精喂养的小鼠中分离的肝细胞 动物对Ca 2+动员激素的反应性增强， 这种增强与增加的敏感性有关， 通过D-肌肌醇1，4，5动员的细胞内Ca 2+储存 三磷酸盐（IP 3）。受体蛋白家族（IP 3R）用于 识别IP 3并作为配体门控的Ca 2+通道， 内部存储。 我们的主要假设是， IP 3受体的调节特性和/或表达是 观察酒精对Ca 2+信号传导的影响。 为了分析 更详细地了解这些作用的机制，我们建议利用培养的 大鼠肝上皮细胞系（WB细胞）作为实验模型。 这些 细胞模拟酒精暴露对Ca 2+信号传导的影响， 动物模型，还含有高水平的IP 3R蛋白。 初步 在这些细胞中的研究表明，IP 3R蛋白可以被下调， 用血管紧张素-II或TGF-β慢性刺激。 我们建议，这些 激动剂和乙醇可能与调节IP 3R的共同机制相互作用 表情 该项目的具体目标是：[1] 表征慢性乙醇暴露对Ca 2+信号传导的影响， WB细胞对激素和生长因子的反应; [2]。 测试 慢性乙醇暴露改变调节特性的假设 IP 3受体; [3]。 为了确定慢性乙醇，血管紧张素II和 TGF-β通过翻译机制改变IP 3R表达; [4]。 以确定 如果慢性乙醇和激动剂处理改变了IP 3R的转录， 基因. 描述慢性酒精中毒的分子机制 暴露改变激素Ca 2+信号传导将有助于理解 酒精对肝细胞生长和损伤的影响。

APPLICANT'S ABSTRACT: Ethanol exposure is known to perturb many signal transduction pathways, including those that involve adenylate cyclase and phosphoinositide turnover. It has been hypothesized that ethanol-mediated alterations in signal transduction pathways may reflect one mechanism by which cells adapt and develop tolerance to the acute effects of ethanol. Previous studies have established that isolated hepatocytes from alcohol-fed animals show an enhanced responsiveness to Ca2+ -mobilizing hormones and that this enhancement is associated with an increased sensitivity of intracellular Ca2+ stores for mobilization, by D-myo-inositol 1,4,5 trisphosphate ( IP3 ). A family of receptor proteins ( IP3R ) serve to recognize IP3 and act as ligand-gated Ca2+ channels that discharge Ca2+ from internal stores. Our principal hypothesis is that an alteration in the regulatory properties and/or expression of IP3 receptors underlies the observed effects of alcohol on Ca2+ signalling. In order to analyze the mechanism of these effects in more detail, we propose to utilize a cultured rat liver epithelial cell line ( WB cells) as an experimental model. These cells mimic the effects of alcohol - exposure on Ca2+ signalling seen in the animal model and also contain high levels of IP3R protein. Preliminary studies in these cells show that IP3R protein can be down-regulated by chronic stimulation with Angiotensin-II or TGF-B. We suggest that these agonists and ethanol may interact with common mechanisms that regulate IP3R expression. The specific aims of this project are: [1] To further characterize the effects of chronic ethanol exposure on Ca2+ signalling in WB cells in response to hormones and growth factors; [2]. To test the hypothesis that chronic ethanol exposure modifies the regulatory properties of IP3 receptors; [3]. To determine if chronic ethanol, Angiotensin-II and TGF-B change IP3R expression by translational mechanisms; [4]. To determine if chronic ethanol and agonist treatment alter the transcription of IP3R genes. Delineating the molecular mechanism by which chronic ethanol exposure alters hormonal Ca2+ signalling will aid in understanding the effects of alcohol on liver cell growth and injury.