Liver SVCT Systems: Vitamin C Uptake, Roles & Regulation

本提案旨在推动主要研究者（PI）实现其学术目标 独立为了达到这个目标，他将学习先进的分子生物学和小鼠遗传学。 他在研究肝脏中维生素C的调节时，使用了多种技术以及肝脏病理学/组织学。抗坏血酸 维生素C是人体必需的微量营养素和有效的抗氧化剂。的两种亚型 钠依赖性维生素C转运蛋白（SVCT 1和SVCT 2）在许多人和小鼠中表达 组织，包括肝脏。关于SVCT的调节或相对贡献，目前尚不清楚 维生素C在肝脏中的吸收过程中起着重要的作用。了解这些机制是 临床相关，因为许多肝脏相关疾病受益于优化维生素C体内稳态。我们 研究将使用体外和体内方法对人体进行全面检查， 肝脏对维生素C的摄取过程及调节。我们将确定维生素C的特性/动力学 摄取，表征hSVCTI和hSVCT 2启动子，建立hSVCTI和hSVCT 2的相对贡献， 使用siRNA方法对hSVCT 2的总摄取进行研究， 调节维生素C的摄取过程，所有这些都在人类肝细胞中进行。此外，我们将确定 图4示出了体内小鼠模型的肝脏中维生素C摄取的特征/动力学，所述体内小鼠模型像人一样不能 为了合成维生素C，确定mSVCT 1和mSVCT 2对总摄取的相对贡献 使用cre/lox系统独立地产生每个基因的肝脏特异性敲除，并继续我们的 研究在该体内模型中维生素C摄取的适应性调节。我们对这些机制的研究 参与维持和调节正常的维生素C体内稳态将有可能使临床医生， 制定有效的战略，为病人在条件不足。广泛的培训和 教育机会将允许PI作为独立的学术研究人员开始职业生涯。

This proposal has been designed to advance the Principle Investigator (PI)towards his goal of academic independence. To attain that objective he will learn advanced molecular biology and mouse genetic techniques as well as liver pathology/histology in his studies of vitamin C regulation in the liver. Ascorbic acid (vitamin C) is a required essential micronutrient and effective antioxidant in humans. Two isoforms of the sodium-dependent vitamin C transporters (SVCT1 and SVCT2) are expressed in many human and mouse tissues, including the liver. Nothing is known regarding the regulation or relative contribution of the SVCT systems toward the overall vitamin C uptake process in the liver. Understanding these mechanisms is clinically relevant since many liver related diseases benefit from optimizing vitamin C body homeostasis. Our studies will use both an in vitro and in vivo approach to perform a comprehensive examination of the human liver vitamin C uptake process and regulation. We will determine the characteristics/kinetics of vitamin C uptake, characterize the hSVCTI and hSVCT2promoters, establish the relative contribution of hSVCTI and hSVCT2 towardtotal uptake using an siRNA approach and perform studies regardingthe effects of adaptive regulation of the vitamin C uptake process, all in human liver cells. In addition we will determine the characteristics/kinetics of vitamin C uptake in the liver of an in vivo mouse model that like humans is unable to synthesize vitamin C, establish the relative contribution of mSVCTI and mSVCT2 toward total uptake using the cre/lox system to generate liver specific knockouts of each gene independently, and continue our studies into adaptive regulation of vitamin C uptake in this in vivo model. Our studies into the mechanisms involved in maintaining and regulating normal vitamin C body homeostasis will potentially allow clinicians to develop effective strategies for patients during conditions of deficiency. The extensive training and educational opportunities will allow the PI to launch into a career as an independent academic researcher.