Mechanisms of Carotenoid Transport and Interactions with Nutrient Absorption

描述(由申请人提供)：候选人：我是一名训练有素的翻译营养学家，专注于研究影响饮食干预生理反应的复杂营养遗传和营养因素。有了分子和细胞生物学和化学的基础，我首先开始研究饮食中植物化学物质的营养方面，通过开发体外植物细胞培养方法来生产同位素标记的植物化学示踪剂，用于啮齿动物代谢研究。在我的营养学博士培训期间，我将这一范例推广到生产稳定的同位素和放射性同位素标记的番茄类胡萝卜素，并研究了未标记的番茄类胡萝卜素在动物模型中的动力学和分布，导致了3篇第一作者和2篇共同撰写的同行评议文章。在我的博士后培训期间，我第一次撰写了4篇研究和评论文章，并与人合著了4篇。我翻译并利用了我之前开发的用于动物和人类新陈代谢研究的示踪工具，发现即使在受控条件下，人类对红色番茄类胡萝卜素番茄红素(与降低几种慢性病和恶性肿瘤的风险有关)的动力学反应也有很大差异。此外，我发现番茄红素和一种结构相似、具有潜在生物活性的番茄类胡萝卜素--植烯的动力学明显不同，而植烯的动力学要高出3倍。 生物利用度较高，从血浆和组织中清除较慢。这部分解释了为什么番茄中含有少量类胡萝卜素(约为番茄红素含量的17%)，但它却是体内的主要类胡萝卜素。研究：为了了解饮食异质性反应的原因并制定策略以提高生物利用度或靶向组织分布，我们必须确定类胡萝卜素细胞摄取和外排的机制。番茄红素和番茄红素是一对引人注目的研究对象，因为它们的生物利用度和生物分布明显不同，而且两者都可能对番茄的许多健康益处做出贡献，包括降低患几种癌症和心血管疾病的风险。最近，全基因组的关联和机制研究表明，细胞脂质转运蛋白与类胡萝卜素状态有关，但这些转运蛋白与番茄红素和植酸的吸收和分配的关系尚不清楚。我们建议研究植物红素和番茄红素与相关运输蛋白之间的相互作用，这些相互作用导致生物利用度和分布的差异，并确定这些 类胡萝卜素可能与共享相同转运蛋白的其他营养化合物的吸收相互作用。目的1.在体外模型中，确定3种候选脂质转运体(SCARB1、CD36或ABCA1)是否介导了对植酸和番茄红素的肠道吸收和前列腺摄取和外排。目的2.利用基因敲除小鼠，确定脂质转运体(SCARB1、CD36和ABCA1&G1)对番茄红素和植酸吸收和全身分布的生理作用。目的3.确定番茄红素或植烯是否以及如何影响两种植物营养素--胡萝卜素(维生素A原)和α-生育酚(维生素E)的吸收，这两种营养素已知由SCARB1和CD36转运。研究生涯发展计划：我在营养学、分析化学和植物化学动力学方面有很强的背景。K99的获奖将使我能够扩大我的研究经验，包括对复杂的基因：植物化学相互作用的机械性、遗传学研究。这一经验将集中在使用体外和遗传小鼠模型来研究脂运输蛋白在类胡萝卜素吸收中的功能。共同导师史蒂文·克林顿和厄尔·哈里森分别是疾病预防的转化营养研究和类胡萝卜素营养生物化学领域的领导者，这使他们成为拟议的K99阶段和我过渡到植物化学-营养遗传学研究职业生涯的理想导师。我将在每周的研究会议上与我的导师互动，但也会与咨询委员会互动， 它将每半年召开一次会议，正式评估我的培训和研究进展。该委员会由食品科学与技术系、医学遗传学系和生物统计学系的教授组成，他们将就K99研究的科学严谨性提供指导，也将为我准备教职申请、实践面试和工作谈判提供指导，以确保我的成功过渡。环境：俄亥俄州立大学和韦克斯纳医学中心是一个非常丰富的跨学科营养和疾病预防研究的环境。俄亥俄州立大学的“作物到临床”项目横跨三所学院，促进了一个多层次、跨学科的研究项目，植物学家、食品科学家、基础和应用营养学家、流行病学家和医生合作研究膳食化合物和功能食品的动力学和生物活性。我的长期职业目标：我的长期目标是：A)在研究型大学建立一个学术实验室，对饮食生物活性化合物营养遗传学、动力学和生物活性进行尖端研究；B)培养饮食生物活性化合物和营养遗传学领域的未来领导者；以及C)促进对饮食植物化学物质的严格调查，以获得关于饮食和补充剂使用的循证建议。影响：通过揭示影响饮食反应的基因：植物化学和营养：植物化学因素，我们将能够设计知情的临床试验，开发公共健康饮食和补充使用建议，以最大限度地提高效益和最大限度地降低风险。培训计划旨在让我成为一名训练有素的跨学科翻译营养学家，为迎接这一挑战做好独特的准备。

DESCRIPTION (provided by applicant): Candidate: I am a trained, translational nutrition scientist focused on investigating the complex nutrigenetic and nutritional factors that impact physiological responses to dietary interventions. With a foundation in Molecular and Cellular Biology and Chemistry, I first began studying the nutritional aspects of dietary phytochemicals by developing in vitro plant cell culture methods for production of isotope-labeled phytochemical tracers for rodent metabolic studies. During my doctoral training in Nutritional Sciences, I extended this paradigm for production of both stable isotope- and radioisotope-labeled tomato carotenoids, and studied the kinetics and distribution of unlabeled tomato carotenoids in animal models, leading to 3 firstauthored and 2 co-authored, peer-reviewed articles. During my postdoctoral training, I first-authored 4 and coauthored 4 research and review articles. I translated and utilized the tracer tools I previously developed, for animal and human metabolic investigation, and found that, even in controlled conditions, human kinetic responses to the red tomato carotenoid, lycopene (associated with a reduced risk of several chronic diseases and malignancies), vary widely. Furthermore, I found the kinetics of lycopene and a structurally similar, potentially bioactive tomato carotenoid, phytoene, to differ markedly, with phytoene being 3-times more bioavailable and more slowly cleared from the plasma and tissues. This partially explained why phytoene, although a minor carotenoid in tomatoes (~17% the level of lycopene), is a major carotenoid in the body. Research: To understand the cause of heterogeneous responses to diet and to devise strategies to enhance bioavailability or target tissue distribution, we must define the mechanisms of carotenoid cellular uptake and efflux. Phytoene and lycopene are a compelling pair to study, as their bioavailability and biodistribution differ markedly, and both likely contribute to the many health benefits of tomato consumption including a decreased risk of several cancers and cardiovascular disease. Recent, genome-wide association and mechanistic studies suggest cellular lipid transporters are associated with carotenoid status, yet how these transporters relate to lycopene and phytoene uptake and distribution is poorly understood. We propose to study the interactions between phytoene and lycopene with associated transport proteins, which lead to differences in bioavailability and distribution, and to determine how these carotenoids may interact with the absorption of other nutritional compounds sharing the same transporters. Aim 1. To determine if intestinal absorption and prostatic uptake and efflux of phytoene and lycopene is mediated by any of 3 (SCARB1, CD36, or ABCA1) candidate lipid transporters in in vitro models. Aim 2. To define the physiological contribution of lipid transporters (SCARB1, CD36, and ABCA1&G1) to lycopene and phytoene absorption and systemic distribution using knockout mice. Aim 3. To determine if and how lycopene or phytoene impact absorption of two phytonutrients, ß-carotene (pro-vitamin A) and α-tocopherol (vitamin E), which are known to be transported by SCARB1 & CD36. Research career development plan: I have a strong background in nutrition, analytical chemistry, and phytochemical kinetics. Award of the K99 will allow me to expand my research experience to include mechanistic, genetic investigations of complex, gene:phytochemical interactions. This experience would center on the use of in vitro and genetic mouse models to study the function of lipid transport proteins in carotenoid absorption. The co-mentors, Steven Clinton and Earl Harrison, are leaders in the fields of translational nutrition research for disease prevention and carotenoid nutritional biochemistry, respectively, making them ideal mentors for the proposed K99 phase and for my transition to a career in phytochemical-nutrigenetic research. I will interact with my mentors weekly at research meetings, but will also interact with an advisory committee, which will meet semi-annually to formally evaluate my training and research progress. The committee consists of professors from the departments of Food Science & Technology, Medical Genetics, and Biostatistics, and will provide guidance both on the scientific rigor of the K99 research, but also on my preparation for faculty job applications, practice interviews, and job negotiations, to assure my successful transition. Environment: The Ohio State University and Wexner Medical Center is a remarkably rich environment for interdisciplinary nutrition and disease prevention research. OSU's "Crops to the Clinic" program spans three colleges and promotes a multi-level, interdisciplinary research program in which plant scientists, food scientists, basic and applied nutritionists, epidemiologists, and physicians collaborate to study the kinetics and bioactivities of dietary compounds and functional foods. Long-term career goals: My long-term goals are to A) establish an academic lab at a research university to conduct cutting-edge studies of dietary bioactive compound nutrigenetics, kinetics, and bioactivities, to B) train future leaders in the field of dietary bioactive compounds and nutrigenetics, and to C) promote rigorous investigations of dietary phytochemicals for evidence-based recommendations on diet and supplement use. Impact: By unraveling the gene:phytochemical and nutrient:phytochemical factors impacting the response to diet, we will be able to design well-informed clinical trials and to develop public health diet and supplement use recommendations to maximize benefits and minimize risks. The training plan is designed for me to become a highly trained, interdisciplinary, translational nutrition scientist who is uniquely prepared to meet this challenge.