Short-Chain Dehydrogenases in Retinol/Sterol Metabolism

视黄醇/甾醇代谢中的短链脱氢酶

• 批准号: 7856985
• 负责人: Natalia Y Kedishvili
• 金额: $ 16.96万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-15 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7856985
• 关键词: Adult; Alcoholic Liver Diseases; Aldehydes; All-Trans-Retinol; Anabolism; Back; Cells; Cellular Retinol Binding Protein; Complement; Development; Enzymes; Equilibrium; Fetal Alcohol Syndrome; Funding; Gene Expression; Genes; Homeostasis; Human; Hydroxysteroids; In Vitro; Knockout Mice; Life; Liver; Metabolism; Modeling; Molecular; Mus; Orthologous Gene; Oxidoreductase; Play; Production; Protein Family; Proteins; Reporting; Retinaldehyde; Retinoids; Retroviral Vector; Role; Skin; Sterols; System; Testing; Tissues; Tretinoin; animal tissue; base; cancer cell; fetal; human tissue; in vivo; mouse model; oxidation; research study; short chain trans-2-enoyl-CoA reductase

Retinoic acid plays an important role in differentiation and development of a wide variety of fetal and adult tissues. Retinoic acid is produced from retinol in two steps: first, retinol is converted to retinaldehyde by a reversible oxidation, and then retinaldehyde is irreversibly oxidized to retinoic acid. The oxidation of retinol is the rate-limiting step in retinoic acid production that determines the overall rate of retinoic acid biosynthesis from retinol. During the previous funding period, we have identified two subfamilies of the human short-chain dehydrogenase/reductase (SDRs) superfamily of proteins that are active toward retinoids. When expressed in intact cells, RoDH-like SDRs confer the ability to oxidize retinol to retinaldehyde, whereas RalR1-like enzymes confer the ability to reduce retinaldehyde back to retinol. Based on these observations, we propose that both groups of human SDRs contribute to retinoid homeostasis in human tissues by regulating the equilibrium between retinol and retinaldehyde, and thereby, regulating the rate of retinoic acid biosynthesis. To test our hypothesis, we propose to characterize retinoid metabolism in human and animal tissues in the presence and in the absence of RoDH- and RalR1-like SDRs. Experiments under the first specific aim will test a hypothesis that silencing of RoDH-like SDR gene expression in human organotypic skin raft culture results in a decreased rate of retinol oxidation to retinaldehyde, whereas silencing of RalR1- like SDR gene expression results in a decreased rate of retinaldehyde conversion to retinol. Experiments under the second specific aim will complement the ex vivo studies in human skin rafts with in vivo studies in RalR1 knockout mouse model and will test a hypothesis that RalR1 is essential for the reduction of retinaldehyde to retinol in mouse tissues. Because in vitro the mouse ortholog of RalR1 is highly active toward medium-chain aldehydes in addition to retinaldehydes, we will also test whether RalR1 contributes to the reduction of medium-chain aldehydes. It has been reported that retinoid homeostasis is disrupted in cancer cells, in alcoholic liver disease and in fetal alcohol syndrome. The proposed studies will provide a better understanding of the molecular bases underlying disregulation of retinoid metabolism in various pathological states.

视黄酸在多种胎儿和成人的分化和发育中起着重要作用 组织。视黄酸由视黄醇分两步生产：首先，视黄醇通过 可逆氧化，然后视黄醛不可逆氧化为视黄酸。视黄醇的氧化反应为 视黄酸生产中的限速步骤，决定视黄酸生物合成的总体速率 来自视黄醇。在上一个资助期间，我们已经确定了人类短链的两个亚科 对类视黄醇具有活性的脱氢酶/还原酶 (SDR) 蛋白质超家族。表达时 在完整细胞中，RoDH 样 SDR 赋予将视黄醇氧化为视黄醛的能力，而 RalR1 样 酶具有将视黄醛还原为视黄醇的能力。根据这些观察，我们 提出两组人类 SDR 通过调节人体组织中的类维生素A稳态 视黄醇和视黄醛之间的平衡，从而调节视黄酸的速率 生物合成。为了检验我们的假设，我们建议表征人类和动物的类维生素A代谢 存在和不存在 RoDH 和 RalR1 样 SDR 的组织。第一个下的实验 具体目标将检验一个假设，即人类器官型中 RoDH 样 SDR 基因表达的沉默 皮筏培养导致视黄醇氧化成视黄醛的速率降低，而 RalR1- 的沉默 SDR 基因表达会导致视黄醛转化为视黄醇的速率降低。实验 在第二个具体目标下，将补充人体皮筏的离体研究与体内研究 RalR1 敲除小鼠模型将检验 RalR1 对于减少 小鼠组织中的视黄醛转化为视黄醇。因为在体外，RalR1 的小鼠直系同源物具有高度活性 除了视黄醛之外，我们还将测试 RalR1 是否有助于中链醛 中链醛的减少。据报道，类视黄醇稳态在 癌细胞、酒精性肝病和胎儿酒精综合症。拟议的研究将提供 更好地了解各种视黄醇代谢失调的分子基础 病理状态。