Rdh10 and retinoic acid effects on differentiation

视黄醇脱氢酶10(RDH10)催化全反式维甲酸(AtRA)的第一步，也是限速步骤 通过生成视黄醇生物合成视黄醇，视网膜脱氢酶将其转化为全反式维甲酸。最高Rdh10 研究的重点是视觉周期或胚胎发育。关于产后的研究工作有限 Rdh10函数。然而，atRA控制着间充质干细胞向脂肪细胞分化的命运。 成骨细胞在成人中调节肥胖和骨骼健康。全反式维甲酸在指导MSC中的作用机制 分化仍不清楚，全反式维甲酸生物合成的调控也是如此。这部文学作品中包含了相互矛盾的 关于atRA和其他分化刺激物调节的主要靶基因的报道。全反式维甲酸的研究最多 脂肪细胞和成骨细胞之间的平衡调节已经在细胞系中完成，并集中在 单个基因控制一个干细胞的命运，通常在分化过程中较晚。使用细胞系(例如3T3- L1、F442a、C2C12、MC3T3-E1)很可能促成了相互矛盾的结论，因为细胞系 原代细胞模型不准确，彼此不同，甚至具有相同标称的细胞系 往往因长期文化的不同而有所不同。本提案旨在解决atRA在指导MSC命运方面的职能 建议对atRA不足的体内模型进行研究，该模型将伴随着原发的 小鼠胚胎成纤维细胞产生全面的机制洞察力确定脂肪细胞与。 成骨细胞的命运。体内模型依赖于具有表型的杂合子消融Rdh10(Rdh10+/-) 在生命早期，随着钙化的减少，骨髓中脂肪细胞的增加和脂肪细胞的增殖增加 成骨细胞。Rdh10+/-模型(纯合子是胚胎致死的)提供了一致的衰减 维生素A在体内的作用是通过在RA中重复减少来实现的。这是一种创新的模式，将提供新的 AtRA在调节脂肪细胞与成骨细胞分化中的作用及新见解 Rdh10的功能和atRA的生物发生。了解Rdh10和atRA在肥胖和肥胖中的作用 脂肪生成有望直接应用于人类健康。这一预期得到了26个国家的支持 与体重指数和体重增加相关的基因间性状与人类Rdh10相近。目标1将 确定降低Rdh10表达和atRA浓度的表型和代谢后果 体内(Rdh10+/-小鼠)，重点研究脂肪细胞和成骨细胞的分化。这一目标将检验这一假设 Rdh10是一种控制全反式维甲酸稳态的主要酶，以调节脂肪细胞中的维甲酸功能和 成骨细胞分化。目的2将确定Rdh10+/-小鼠的表型背后的机制(S) 关于细胞命运的决定。这一目标将使用两套MEF：1)来自Rdh10+/-小鼠；2)永生 用完全敲除Rdh10的MEF来检验由Rdh10产生的atRA指导成熟的假说 MSC通过调控基因的表达很早就决定了细胞的命运，并将识别反应基因。

Retinol dehydrogenase 10 (Rdh10) catalyzes the first and rate-limiting step in all-trans-retinoic acid (atRA) biosynthesis from retinol by generating retinal, which retinal dehydrogenases convert into atRA. Most Rdh10 research has focused on the visual cycle or embryonic development. Limited work has been done on postnatal Rdh10 function. Yet, atRA controls the fate of mesenchymal stem cell (MSC) differentiation into adipocytes vs osteoblasts in the adult to regulate adiposity and bone health. Mechanisms of atRA action in directing MSC differentiation remain unclear as does regulation of atRA biosynthesis. The literature contains conflicting reports as to the primary target genes regulated by atRA and other differentiation stimuli. Most studies of atRA regulation of the balance between adipocytes vs osteoblasts has been done in cell lines, and has focused on single genes controlling in one stem cell fate, often later during differentiation. The use of cell lines (e.g. 3T3- L1, F442A, C2C12, MC3T3-E1) most likely has contributed to the conflicting conclusions, because cell lines do not faithfully model primary cells, differ from each other, and even cell lines with the same nominal designation often differ as a result of long-term culture. This proposal addresses atRA function in directing MSC fate by proposing study of an in vivo model of atRA insufficiency, which will be accompanied by generating primary mouse embryonic fibroblasts to produce comprehensive mechanistic insight into determining adipocyte vs. osteoblast cell fates. The in vivo model relies on heterozygote ablated Rdh10 (Rdh10+/-) that has a phenotype of increased adiposity and adipocyte proliferation in bone marrow early in life, with decreased calcification of osteoblasts. The Rdh10+/- model (the homozygote is embryonic lethal) provides for consistently attenuated vitamin A function in vivo through reproducibly reduced atRA. This is an innovative model that will provide new insight into atRA function concerning regulating differentiation of adipocytes vs osteoblasts, and new insight into Rdh10 function and atRA biogenesis. Understanding the roles of Rdh10 and atRA in obesity and adipogenesis promises direct human health applications. This expectation is supported by the twenty-six intergenic traits related to body mass index and weight gain that map close to human Rdh10. Aim 1 will determine the phenotype and metabolic consequences of reducing Rdh10 expression and atRA concentrations in vivo (Rdh10+/- mice), focusing on adipocyte and osteoblast differentiation. This aim will test the hypothesis that Rdh10 is a major enzyme that controls atRA homeostasis to regulate retinoid function in adipocyte and osteoblast differentiation. Aim 2 will determine mechanism(s) that underlie the phenotype of Rdh10+/- mice with respect to cell fate determination. This aim will use two sets of MEF: 1) from Rdh10+/- mice; 2) immortalized MEF with a total knockout of Rdh10 to test the hypothesis that atRA generated by Rdh10 directs maturation of MSC by regulating gene expression very early in cell fate determination, and will identify the responsive genes.