RETINOID METABOLISM IN STELLATE CELLS

这是一个R21发展赠款申请，以支持一个合作的国际项目（PA-96-033）。两名美国研究人员的合作，W。Bosron和N. Kedishvili和两名意大利研究人员，A。Casini和A.加利成立了。W. Bosron和N. Kedishvili在类维生素A代谢中涉及的酶和水解酶的特性方面具有专业知识。Casini和Galli博士在星状细胞的制备和培养以及与星状细胞活化相关的生化事件的表征方面具有专业知识，这些生化事件导致酒精诱导的肝纤维化。这项研究计划的总体目标是确定肝星状细胞激活形成肌纤维母细胞样细胞时视黄酯代谢的代谢途径。肝星状细胞是肝脏中维生素A的主要储存库。当动物长期暴露于酒精或其他肝毒素时，星状细胞被激活并转化为肌纤维母细胞样细胞。 这些转化细胞是酒精诱导的肝纤维化中胶原蛋白合成和细胞外基质形成的位点。星状细胞活化的最早期事件之一是棕榈酸视黄酯的水解。已报道人、兔和大鼠肝脏中存在多种视黄酯水解酶和视黄醇脱氢酶活性。然而，在肝星状细胞活化过程中参与视黄酯代谢的特定酶和基因尚未确定。具体目标是开发从大鼠、兔和/或人肝脏制备星状细胞的方法，以鉴定星状细胞活化过程中存在的视黄酯水解酶和视黄醇脱氢酶的同工酶。将在细胞中测量酶活化。棕榈酸视黄酯水解酶和视黄醇脱氢酶的催化和分子特性将被表征。这些研究将为维甲酸代谢在酒精性肝病中的作用提供新的信息。

This is an R21 developmental grant application to support a collaborative international project (PA-96-033). A collaboration between two United States investigators, Drs. W. Bosron and N. Kedishvili, with two Italian investigators, Drs. A. Casini and A. galli has been established. Drs. W. Bosron and N. Kedishvili have expertise in the characterization of dehydrogenases and hydrolases involved in retinoid metabolism. Drs. Casini and Galli have expertise in the preparation and culture of stellate cells and the characterization of biochemical events associated with stellate cell activation leading to alcohol-induced hepatic fibrosis. The overall goal of the research proposal is to identify the metabolic pathways of retinyl ester metabolism in hepatic stellate cells when they become activated to form myofibroblast-like cells. Hepatic stellate cells are the main reservoir of Vitamin A in liver. When animals are chronically exposed to alcohol or other hepatotoxins, the stellate cells become activated and transform into myofibroblast-like cells. These transformed cells are the sites of collagen synthesis and extracellular matrix formation in alcohol-induced hepatic fibrosis. One of the earliest events in stellate cell activation is the hydrolysis in retinyl palmitate esters. Multiple retinyl ester hydrolase and retinol dehydrogenase activities have been reported in human, rabbit and rat liver. However, the specific enzymes and genes involved in retinyl ester metabolism during the activation of hepatic stellate cells have not been identified. The specific aims are to develop methods to prepare stellate cells from rat, rabbit and/or human liver to identify the isoenzymes of retinyl ester hydrolases and retinol dehydrogenases present during stellate cell activation. The enzyme activation will be measured in cells. The catalytic and molecular properties of the retinyl palmitate hydrolases and retinol dehydrogenases will be characterized. The studies should provide new information on the role of retinoid metabolism in alcohol-induced liver disease.