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.

视黄酸在各种胎儿和成人的分化和发展中起重要作用 组织。视黄醇分为两个步骤产生视网膜酸：首先，视黄醇通过A转化为视网膜水 可逆的氧化，然后视网膜醛被不可逆地氧化为视黄酸。视黄醇的氧化是 视黄酸产生的速率限制步骤决定了视黄酸生物合成的总体速率 来自视网膜。在上一个资金期间，我们已经确定了人类短链的两个亚家族 脱氢酶/还原酶（SDRS）的蛋白质超家族，这些蛋白具有活性的类视黄素。表达时 在完整的细胞中，类似RODH的SDR赋予视黄醇氧化为视网膜水的能力，而RALR1样的能力 酶赋予将视网膜醛减为视黄醇的能力。基于这些观察，我们 提出，两组人类SDR通过调节人类组织中的视网膜类动态稳态有助于 视黄醇和视网膜醛之间的平衡，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中的类视感代谢 在存在的情况下，在不存在RODH和RALR1样SDR的情况下。第一个实验 具体目标将检验一个假设，即人体器官中RoDH样SDR基因表达的沉默 皮肤筏培养会导致视网膜氧化的视网膜氧化速率降低，而RALR1-的沉默 像SDR基因表达一样，视网膜甲醛转化为视黄醇的速率降低。实验 在第二个特定目标下，将与人体皮肤筏中的离体研究补充体内研究 RALR1敲除小鼠模型，并将检验一个假设RALR1对于还原至关重要 小鼠组织中的视网膜甲醛到视黄醇。因为在体外，ralr1的小鼠直系同源物高度活跃 除了视网膜葡萄酒外，我们还将测试RALR1是否有助于中链醛。 中链醛的还原。据报道，类维生素类稳态被破坏 癌细胞，酒精性肝病和胎儿酒精综合征。拟议的研究将提供 更好地理解各种视黄代谢的疏离基础的分子碱基 病理状态。