Molecular determinants of retinoid metabolism in embryonic tissues

胚胎组织中类维生素A代谢的分子决定因素

• 批准号: 9036421
• 负责人: MAUREEN A KANE
• 金额: $ 31.07万
• 依托单位: UNIVERSITY OF KANSAS LAWRENCE
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-17 至 2019-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9036421
• 关键词: Ablation; All-Trans-Retinol; Analytical Chemistry; Animal Model; Anterior; Binding; Biological Assay; Biological Process; Blindness; Cardiac development; Carotene; Catabolism; Cephalic; Cessation of life; Child; Childhood; Collaborations; Congenital Abnormality; Congenital Disorders; Defect; Developing Countries; Development; Diet; Disease; Embryo; Embryology; Embryonic Development; Enzymatic Biochemistry; Enzymes; Equilibrium; Exposure to; Feedback; Gene Targeting; Genes; Genetic; Goals; Health; Homeostasis; Immune; Immune System Diseases; Inborn Genetic Diseases; Inflammation; Knowledge; Life; Malignant Neoplasms; Metabolism; Modeling; Molecular; Mus; Nuclear Hormone Receptors; Obesity; Pathway interactions; Pattern; Phenotype; Physiological; Play; Pregnancy; Prevention; Prevention approach; Process; Production; Property; Provitamin A Carotenoid; Public Health; Regulation; Reporter; Research; Research Personnel; Retinaldehyde; Retinoids; Retinol Metabolism Pathway; Role; Signal Transduction; Skeletal Development; Supplementation; Testing; Therapeutic; Time; Tissue Model; Tissues; Toxic effect; Tretinoin; Vitamin A; Work; base; blind; cardiogenesis; design; developmental disease; dietary supplements; embryo tissue; feeding; in vivo; interest; mouse model; novel strategies; oxidation; postnatal; prevent; skin disorder; stem; therapy development

DESCRIPTION (provided by applicant): The vitamin A metabolite, all-trans-retinoic acid (ATRA), plays essential roles in a multitude of biological processes throughout life and has shown promising results in several therapeutic settings. However, exposure to either reduced or excess levels of ATRA during pregnancy can result in abnormalities in embryonic development. The specific goal of this project is to determine the factors that control the formation of ATRA in vivo. The long-term goal is to develop therapies based on the manipulation of the endogenous levels and activity of ATRA in diseased tissues. The central hypothesis is that ATRA regulates its own synthesis via a homeostatic feedback mechanism by controlling the balance of the oxidation of retinol versus the reduction of retinaldehyde. Current studies have largely ignored the role of enzymes that carry out the reduction of retinaldehyde in the regulation of ATRA levels. The overall objective of this application is to determine the role and regulation of DHRS3, shown here to be a pivotal enzyme in vitamin A metabolism. This hypothesis is based on preliminary results derived from the characterization of a Dhrs3-deficient mouse model. These results indicate that 1) DHRS3 is the predominant enzyme responsible for the reduction of retinaldehyde during development and 2) the reduction of retinaldehyde by DHRS3 is indispensable for ATRA homeostasis and normal embryonic development. Testing of the central hypothesis will be pursued in three specific aims: Aim 1 studies will establish 1) the enzymatic properties of DHRS3, 2) the mechanism of regulation of Dhrs3 by ATRA, and 3) the spatial- temporal pattern of the expression of Dhrs3 during development. This knowledge is essential for understanding the physiological role of DHRS3. Studies described in Aim 2 will determine the role of DHRS3 in vitamin A metabolism based on the working hypothesis that DHRS3 is the main enzyme responsible for reducing retinaldehyde during embryogenesis. Aim 2 will be pursued by establishing the effect of Dhrs3-ablation on the metabolism of retinol and provitamin A carotenoids by 1) LC-UV and LC-MS/MS analysis of the levels of retinoids, and 2) assaying the expression of ATRA-target genes in the tissues of Dhrs3-/- embryos. Aim 3 will test the hypothesis that the developmental defects caused by ablation of Dhrs3 are a result of altered ATRA metabolism. Preliminary studies indicate that Dhrs3-/- embryos have defects in anterior-posterior patterning, cardiac and skeletal development, and are non-viable. Aim 3 will be pursued by characterizing the pathways responsible for the observed developmental defects in relation to altered ATRA formation. Therefore, the effect of diet, genetic background and inhibition of vitamin A metabolism on the manifestation of developmental defects associated with Dhrs3-ablation will be examined. These studies aim to further establish the processes responsible for the regulation of ATRA formation in vivo and contribute to a framework for the long-term goal of developing approaches to prevent and treat congenital and inherited disorders associated with altered ATRA-signaling.

描述（由申请人提供）：维生素A代谢产物，全反替酸（ATRA）在整个生命的众多生物学过程中都起着重要作用，并且在几种治疗环境中显示出令人鼓舞的结果。但是，在怀孕期间暴露于降低或过量的ATRA水平会导致胚胎发育异常。该项目的具体目标是确定控制ATRA形成的因素 体内。长期目标是根据对患病组织中ATRA的内源性水平和活性的操纵来开发疗法。中心假设是ATRA通过控制视网膜氧化与视网膜脱水的减少的氧化平衡，通过稳态反馈机制来调节其自身的合成。当前的研究在很大程度上忽略了酶在ATRA水平调节中的减少酶的作用。该应用的总体目的是确定DHRS3的作用和调节， 这里显示为维生素A代谢中的关键酶。该假设基于从DHRS3缺陷小鼠模型的表征得出的初步结果。这些结果表明，1）DHRS3是负责在发育过程中减少视网膜甲醛的主要酶，而2）DHRS3减少视网膜醛，对于ATRA稳态和正常胚胎发育是必不可少的。中央假设的测试将在三个具体目的中进行：目标1研究将建立1）DHRS3，2）ATRA调节DHRS3的酶学特性，以及3）DHRS3表达的空间时间模式在开发过程中。这种知识对于理解DHRS3的生理作用至关重要。 AIM 2中描述的研究将基于工作假设确定DHRS3在维生素A代谢中的作用，即DHRS3是负责在胚胎发生过程中降低视网膜氢的主要酶。 AIM 2将通过确定DHRS3启动对视黄醇和Provitamin a类胡萝卜素代谢的影响1）通过1）LC-UV和LC-MS/MS分析性类维生素的水平，以及2）分析Atra--- DHRS3 - / - 胚胎组织中的靶基因。 AIM 3将检验以下假设：DHRS3消融引起的发育缺陷是ATRA代谢改变的结果。初步研究表明，DHRS3 - / - 胚胎在前后图案，心脏和骨骼发育中存在缺陷，并且不可行。 AIM 3将通过表征导致与ATRA形成改变的观察到的发育缺陷的途径来追求AIM 3。因此，将检查饮食，遗传背景和抑制维生素A代谢对与DHRS3抗性相关的发育缺陷表现的影响。这些研究旨在进一步建立负责调节体内ATRA形成的过程，并为开发与改变ATRA信号改变的先天性和遗传疾病的长期目标的框架有助于框架。