Alcohol alters hepatic microtubule and membrane dynamics

描述（由申请人提供）：每年有超过20,000人死于酒精性肝病，这是美国第七大死因。由于肝脏是乙醇代谢的主要部位，它是最容易受到酒精性损伤的器官。在疾病的早期阶段，脂肪肝的发展导致肝细胞坏死、肝纤维化，并最终导致肝硬化。尽管疾病的进展在临床上有很好的描述，但酒精性肝损伤的分子基础尚不清楚。我们的长期目标是了解导致酒精诱导肝毒性的机制。我们最近的研究是在培养的wi - b细胞中进行的。这些肝细胞高度分化，并在培养中保持肝脏特异性活动，包括有效代谢乙醇的能力。因此，这些细胞是检验酒精诱导肝毒性的极好模型，并允许我们进行无法在动物身上进行的机制研究。最近，我们发现在乙醇处理的细胞中，微管更稳定，乙酰化程度是对照组的2-3倍。我们在乙醇喂养大鼠的肝细胞中证实了这些结果，表明这些发现具有生理学意义。我们进一步确定，在wi - b细胞中增加的微管乙酰化依赖于乙醇代谢。这一建议侧重于从这些最近的结果中出现的两个主要问题。首先，是什么机制导致：；乙醇处理细胞中微管超乙酰化和稳定性增加，其他肝蛋白超乙酰化是否通过类似机制？其次，我们将检测微管是否过度乙酰化；有助于在蛋白质运输中观察到的酒精诱导缺陷。我们在培养和使用wi - b细胞以及极化肝细胞蛋白运输方面的专业知识使我们能够完美地进行这些探索性的机械实验。这些新的研究领域将为新的方法和假设打开大门，我们将应用于我们未来的肝毒性研究。

DESCRIPTION (provided by applicant): More than 20,000 people each year die of alcoholic liver disease, the seventh largest cause of death in Americans. Because the liver is the major site of ethanol metabolism, it is the most susceptible organ to alcohol-induced injury. In the early stages of the disease, a fatty liver develops which leads to hepatocyte necrosis, liver fibrosis, and ultimately to cirrhosis. Although the disease progression is well described clinically, the molecular basis for alcohol-induced liver injury is not understood. Our long-term goal is to understand the mechanisms that lead to alcohol-induced hepatotoxicity. Our recent studies have been performed in cultured WIF-B cells. These hepatic cells are highly differentiated and maintain liver-specific activities in culture, including the ability to efficiently metabolize ethanol. Thus, these cells are an excellent model to examine alcohol-induced hepatotoxicity and allow us to perform mechanistic studies that cannot be done in animals. Recently, we found that microtubules are more stable and acetylated 2-3-fold more in ethanol-treated cells than in control. We confirmed these results in hepatocytes from ethanol-fed rats indicating the findings have physiologic importance. We further determined that increased microtubule acetylation in WIF-B cells is dependent on ethanol metabolism. This proposal focuses on two major questions emerging from these recent results. First, what is the mechanism that leads:; to microtubule hyperacetylation and increased stability in ethanol-treated cells and are other hepatic proteins hyperacetylated via similar mechanisms? Secondly, we will test whether microtubule hyperacetylation ;contributes to alcohol-induced defects observed in protein trafficking. Our considerable expertise in the culture and use of WIF-B cells and our expertise in polarized hepatocyte protein trafficking situate us perfectly to perform these exploratory, mechanistic experiments. These novel research areas will open the door to novel approaches and hypotheses that we will apply to our future studies of hepatotoxicity.