Short-Chain Dehydrogenases in Retinol/Sterol Metabolism

视黄醇/甾醇代谢中的短链脱氢酶

• 批准号: 10545743
• 负责人: Natalia Y Kedishvili
• 金额: $ 43.44万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-06 至 2024-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10545743
• 关键词: Acceleration; Adult; All-Trans-Retinol; Anabolism; Antibodies; Area; Beta Carotene; Binding; Cell Nucleus; Cells; Complex; Cues; Custom; Cytoplasm; Darkness; Data; Development; Disease; Embryo; Embryonic Development; Enzymes; Exhibits; Eyelid structure; Funding; Future; Gambling; Genes; Goals; Growth; Hair; Hair follicle structure; Health; Homeostasis; In Vitro; Knock-out; Knockout Mice; Knowledge; Laboratories; Light; Maintenance; Mammals; Metabolism; Molecular; Mus; Natural regeneration; Nuclear; Organ; Oxidoreductase; Pathway interactions; Pattern; Performance; Periodicity; Peripheral; Phase; Phenotype; Physiological; Physiological Processes; Production; Proteins; Publishing; RXR; Regulation; Reporting; Research; Research Personnel; Retinaldehyde; Retinoids; Retinol dehydrogenase; Role; Signal Transduction; Skin; Statistical Data Interpretation; Sterols; Supplementation; Testing; Texas; Therapeutic Intervention; Time; Tissues; Tretinoin; Vitamin A; Woman; cell type; circadian pacemaker; embryo tissue; gland development; improved; in vivo; infancy; knockout gene; malformation; meibomian gland; meibomian gland dysfunction; mouse model; novel; novel strategies; oxidation; response; spatiotemporal; therapeutically effective; transcription factor

All-trans-retinoic acid (RA) is the bioactive derivative of vitamin A and β-carotene that is essential for differentiation and development of embryonic tissues as well as the maintenance and robust performance of adult organs and tissues. In the nucleus, RA acts by binding to RXR/RAR heterodimeric transcription factors to regulate the expression of over 530 genes. RA is also known to have regulatory functions in the cytoplasm. During embryogenesis the levels of RA change in a strictly defined spatiotemporal pattern. Similarly, during adulthood the concentration of RA in various tissues and cells is maintained within narrow margins that are optimal for each type of cell. Disruption of RA homeostasis results in embryonic malformations, whereas in adult tissues aberrations in RA homeostasis can lead to pathophysiological changes that result in disease. Thus, it is critical to understand: (1) the molecular mechanisms whereby the cells maintain RA homeostasis; (2) how the cells adjust RA levels in response to varied physiological requirements; and (3) why these mechanisms fail in disease. Since the oxidation of retinol to retinaldehyde is the rate-limiting step in the pathway of RA biosynthesis that controls the overall rate of RA biosynthesis, it is important to identify and characterize the enzymes that catalyze this step and to understand the contribution of each enzyme to overall RA homeostasis. During the previous funding cycle, it was established that the baseline levels of RA in cells are maintained by a heterooligomeric retinoid oxidoreductase complex (ROC) formed by retinol dehydrogenase 10 (RDH10) and dehydrogenase/reductase 3 (DHRS3). Data from this and other laboratories indicate that RDH10 is also the primary enzyme responsible for the oxidation of retinol to retinaldehyde during early stages of embryogenesis. However, other yet unidentified retinol dehydrogenases appear to be more important in adult tissues. Preliminary data from this laboratory indicate that mice with a double knockout of genes encoding retinol dehydrogenase epidermal 2 (RDHE2) and RDHE2-similar (RDHE2S), display a phenotype consistent with reduced RA signaling in skin pilosebaceous unit and meibomian glands of eyelids. The data also suggest that the expression of RDHE2 and RDHE2S oscillates in a diurnal pattern and during various stages of hair follicle regeneration. We hypothesize that these inducible and RA-sensitive enzymes are responsible for the fluctuations of RA during the cycle of hair follicle regeneration, and for fine-tuning of the baseline RA levels, established by the ROC, in response to varied physiological requirements or pathophysiological conditions. To test this hypothesis, we will use the novel mouse models and custom-made antibodies generated during the previous cycle to determine the contribution of RDHE2/E2S to RA biosynthesis in skin and meibomian glands of the eyelid. The proposed studies will provide a comprehensive background to better understand the molecular mechanisms that maintain and/or disrupt RA homeostasis and will inform future strategies to develop targeted and more effective therapeutic interventions.

全反式视黄酸 (RA) 是维生素 A 和 β-胡萝卜素的生物活性衍生物，对于胚胎组织的分化和发育以及成体器官和组织的维持和稳健性能至关重要，RA 在细胞核中发挥作用。通过与 RXR/RAR 异二聚体转录因子结合来调节 530 多个基因的表达，已知 RA 在细胞质中具有调节功能，在胚胎发生过程中，RA 的水平会在严格定义的时空范围内发生变化。同样，在成年期，各种组织和细胞中的 RA 浓度维持在最适合每种类型细胞的狭窄范围内，RA 稳态的破坏会导致胚胎畸形，而在成人组织中 RA 稳态的异常可能会导致病理生理学。因此，了解以下因素至关重要：(1) 细胞维持 RA 稳态的分子机制；(2) 细胞如何根据不同的生理情况调整 RA 水平。 (3)为什么这些机制在疾病中失败，因为视黄醇氧化成视黄醛是该过程中的限速步骤。 RA 生物合成途径控制着 RA 生物合成的总体速率，因此识别和表征催化该步骤的酶并了解每种酶对 RA 总体稳态的贡献非常重要。细胞中 RA 的基线水平由视黄醇脱氢酶 10 (RDH10) 形成的异寡聚类视黄醇氧化还原酶复合物 (ROC) 维持，该实验室和其他实验室的数据表明，RDH10 也是胚胎发生早期阶段将视黄醇氧化为视黄醛的主要酶，但其他尚未鉴定的视黄醇脱氢酶似乎在成人中更为重要。该实验室的初步数据表明，编码视黄醇脱氢酶表皮 2 基因被双重敲除的小鼠。 (RDHE2) 和 RDHE2 类似物 (RDHE2S)，显示出与皮肤毛囊皮脂腺单位和眼睑睑板腺中 RA 信号传导减少一致的表型。数据还表明 RDHE2 和 RDHE2S 的表达以昼夜模式和在不同阶段振荡。我们认为这些诱导型和 RA 敏感酶是导致 RA 在毛囊再生周期中波动的原因。毛囊再生，并微调 ROC 建立的基线 RA 水平，以响应不同的生理需求或 为了检验这一假设，我们将使用上一个周期中产生的新型小鼠模型和定制抗体来确定 RDHE2/E2S 对皮肤和眼睑睑板腺中 RA 生物合成的贡献。一个全面的背景，可以更好地理解维持和/或破坏 RA 稳态的分子机制，并将为未来制定有针对性和更有效的治疗干预策略提供信息。