Nuclear receptor mediated bile acid alterations and coagulopathy in protein-energy undernutrition

蛋白质能量营养不良中核受体介导的胆汁酸改变和凝血病

• 批准号: 9765307
• 负责人: Geoffrey A Preidis
• 金额: $ 16.26万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9765307
• 关键词: 5 year old; 7alpha hydroxylase; Address; Advisory Committees; Affect; Agonist; Anemia; Animal Model; Atmosphere; Autophagocytosis; Bile Acid Biosynthesis Pathway; Bile Acids; Binding; Bioinformatics; Biology; Blood Coagulation Disorders; Blood Coagulation Factor; Body Weight decreased; CYP7A1 gene; Cessation of life; ChIP-seq; Child; Childhood; Cholesterol; Clinical; Coagulation Process; Comorbidity; Contusions; DNA; DNA Binding; Detection; Development; Development Plans; Diet; Dietary Fats; Digestion; Digestive System Disorders; Doctor of Medicine; Doctor of Philosophy; Elements; Environment; Enzymes; Etiology; Exhibits; Fasting; Fat-Soluble Vitamin; Fatty acid glycerol esters; Feces; Fibrinogen; Fostering; Foundations; Funding; Gastroenterologist; Gastroenterology; Gene Expression; Gene Expression Profile; Genes; Genetic Transcription; Gluconeogenesis; Goals; Growth; Health; Hemorrhage; Hepatology; High-Throughput Nucleotide Sequencing; Homeostasis; Hospital Costs; Impairment; Institution; International; Intestines; Knowledge; Laboratories; Lead; Life; Link; Lipolysis; Liver; Malabsorption Syndromes; Malnutrition; Measurement; Measures; Mediating; Medical; Medical Care Costs; Medical center; Medicine; Mentorship; Metabolic Pathway; Metabolism; Metagenomics; Micelles; Mixed Function Oxygenases; Modeling; Molecular; Motion; Mus; Mutation; Nuclear Hormone Receptors; Nuclear Receptors; Nutrient; Nutritional Study; Nutritional status; Outcome; PPAR alpha; Pathologic; Pathway interactions; Pediatric Hospitals; Pediatrics; Pharmacology; Physicians; Physiological; Physiological Processes; Plasma; Process; Promoter Regions; Proteins; Prothrombin time assay; Publications; Quality of life; Receptor Signaling; Regulation; Repression; Research; Research Personnel; Role; Route; Schools; Science; Scientist; Signal Transduction; Site; Small Intestines; Sterols; Testing; Texas; Therapeutic; Time; TimeLine; Tissues; Training; Translational Research; United States; United States National Institutes of Health; Vitamin Deficiency; Vitamin K; Weight Gain; Western Blotting; Wild Type Mouse; Work; absorption; activation product; base; career; career development; college; design; detection of nutrient; fatty acid oxidation; gene repression; genome-wide; global health; gut bacteria; healthy weight; improved; liver function; loss of function mutation; mortality; mouse model; novel; novel therapeutics; nutrient deprivation; nutrition; oxysterol 7-alpha-hydroxylase; prevent; promoter; receptor; response; socioeconomics; symposium; targeted treatment; transcriptome sequencing; young adult

PROJECT SUMMARY/ABSTRACT Protein-energy undernutrition (PEU) is implicated in half of all global deaths under five years of age and remains one of the most pressing challenges in pediatrics today. PEU sets into motion a vicious cycle of liver function abnormalities that further erode health. For example, intestinal bile acids are markedly reduced in children with PEU, resulting in poor dietary fat absorption and impaired weight gain. In severe cases, vitamin K- independent coagulopathy can lead to catastrophic bleeding. Mechanisms by which PEU alters these two processes are unknown, although evidence implicates the nutrient-sensing nuclear receptors, farnesoid X receptor (FXR) and peroxisome proliferator-activated receptor (PPAR)α. FXR is activated in the fed state by bile acids, while PPARα is activated in the fasted state by products of lipolysis. These receptors regulate bile acid homeostasis and other liver functions, competing for binding to many of the same promoter regions with opposite transcriptional effects. Children with mutations in the gene encoding FXR also have vitamin K-independent coagulopathy with transcriptional repression of multiple coagulation factors including fibrinogen, implicating FXR signaling in the coagulopathy of PEU. To investigate the role of nuclear receptors in these two liver functions, we examined mouse models of early-life PEU, each of which exhibits globally decreased bile acids and coagulopathy. Gene expression patterns in our young adult mice demonstrate Pparα activation, Fxr signal loss, and transcriptional repression of genes that promote bile acid synthesis and coagulation. Based on these findings, our hypothesis is that Pparα activation by products of lipolysis generated in PEU transcriptionally represses key genes in bile acid synthesis leading to decreased intestinal bile acids and impaired weight gain. Furthermore, we hypothesize that activated Pparα displaces Fxr from shared DNA promoter regions, mediating coagulopathy by decreasing transcription of Fxr-dependent genes. This hypothesis will be tested with two specific aims. In Aim 1, PEU and healthy wild type mice treated with Pparα agonist or antagonist, along with PEU and healthy Pparα-/- mice, will be used to determine how Pparα drives changes in the expression of genes that regulate bile acid pool size by qPCR, bile acid concentrations by LC-MS/MS, and growth impairment over time. In Aim 2, wild type mice treated with Pparα and Fxr agonists and antagonists will be used to determine whether competitive DNA binding between the two nuclear receptors results in coagulopathy through transcriptional repression of Fxr-dependent coagulation factors; these studies will employ ChIP-seq, RNA-seq, and plasma coagulation measurements. Our expected outcomes are characterization of a novel molecular link, mediated by nuclear hormone receptors, between the regulation of bile acid homeostasis and coagulation, both of which are pathologically altered in PEU. These studies will provide the foundation for developing new pharmacologic and diet-based therapeutic strategies that could ultimately be generalizable to children with weight loss due to a variety of medical and socioeconomic causes. Geoffrey A. Preidis, M.D., Ph.D. is currently a fellow in Pediatric Gastroenterology, Hepatology, and Nutrition at Baylor College of Medicine. He has a strong publication record in metagenomics, global health, and nutrition research with children and animal models of PEU. His long-term goal is to become an independent NIH-funded physician-scientist investigating co-morbidities that result from nutrient deprivation early in life. These research aims support the PI’s career development by building upon his background in pediatric gastroenterology and graduate work in metagenomics, with new training in nuclear receptor biology and advanced applications of high- throughput sequencing and bioinformatic analysis. Additional key elements of the training plan include: 1) A mentorship and advisory team of internationally recognized, independently funded investigators with expertise in all aspects of the development plan, including David Moore, Ph.D. (nuclear receptor biology), Aleksandar Milosavljevic, Ph.D. (genome-wide bioinformatics), and Robert Shulman, M.D. (clinical translational research and pediatric gastroenterologist academic career development); 2) Advanced coursework in nuclear receptor biology and bioinformatics from the Baylor College of Medicine Graduate School of Biomedical Sciences, Cold Spring Harbor Laboratory, FASEB Science Research Conferences, and Keystone Symposia; and 3) Scholarly activities designed to foster independence. The PI’s training environment is a premiere academic research institution closely allied with the world’s largest medical center, the nation’s largest children’s hospital, and the NIH-funded Texas Medical Center Digestive Disease Center. This environment will provide a collaborative, supportive, and productive atmosphere to facilitate completion of all research aims and development goals in the proposed timeline. In summary, this training plan will place the PI on a direct route to a successful career as an independent investigator while identifying novel pathways by which liver function impairments in PEU develop and may ultimately be prevented and treated.

项目概要/摘要 全球五岁以下死亡人数中有一半与蛋白质能量营养不足 (PEU) 有关 仍然是当今儿科最紧迫的挑战之一。 PEU 引发肝脏恶性循环 功能异常进一步损害健康。例如，肠道胆汁酸显着减少 患有PEU的儿童，会导致膳食脂肪吸收不良和体重增加受损。在严重的情况下，维生素K- 独立凝血障碍可导致灾难性出血。 PEU 改变这两者的机制 尽管有证据表明营养感应核受体法尼醇 X 的作用过程尚不清楚 受体（FXR）和过氧化物酶体增殖物激活受体（PPAR）α。 FXR 在进食状态下被胆汁激活 酸，而 PPARα 在禁食状态下被脂解产物激活。这些受体调节胆汁酸 体内平衡和其他肝脏功能，竞争与许多具有相反的相同启动子区域的结合 转录效应。 FXR 编码基因突变的儿童也存在维生素 K 不依赖症 凝血病伴有多种凝血因子（包括纤维蛋白原）转录抑制，与 FXR 相关 PEU 凝血病中的信号传导。为了研究核受体在这两种肝功能中的作用， 我们检查了生命早期 PEU 的小鼠模型，每个模型都表现出整体胆汁酸下降，并且 凝血病。我们年轻成年小鼠的基因表达模式表明 Pparα 激活、Fxr 信号丢失、 以及促进胆汁酸合成和凝血的基因的转录抑制。基于这些 结果，我们的假设是，PEU 中产生的脂肪分解产物可激活 Pparα 转录抑制胆汁酸合成的关键基因，导致肠道胆汁酸减少 和体重增加受损。此外，我们假设激活的 Pparα 取代了共享的 Fxr DNA 启动子区域，通过减少 Fxr 依赖性基因的转录来介导凝血病。 该假设将通过两个具体目标进行检验。在目标 1 中，PEU 和健康野生型小鼠接受 Pparα 激动剂或拮抗剂以及 PEU 和健康 Pparα-/- 小鼠将用于确定 Pparα 如何发挥作用 通过 qPCR 驱动调节胆汁酸库大小的基因表达变化，通过 LC-MS/MS，以及随时间推移的生长障碍。在目标 2 中，用 Pparα 和 Fxr 激动剂治疗的野生型小鼠 拮抗剂将用于确定两个核受体之间是否竞争性 DNA 结合 通过 Fxr 依赖性凝血因子的转录抑制导致凝血病；这些研究 将采用 ChIP-seq、RNA-seq 和血浆凝固测量。我们的预期结果是 表征由核激素受体介导的新型分子联系 胆汁酸稳态和凝血功能在 PEU 中均发生病理改变。这些研究将提供 为开发新的药理学和基于饮食的治疗策略奠定了基础，这些策略最终可能会被实现 适用于由于各种医学和社会经济原因而体重减轻的儿童。 杰弗里·A·普雷迪斯 (Geoffrey A. Preidis)，医学博士、哲学博士目前是儿科胃肠病学、肝病学和营养学研究员 在贝勒医学院。他在宏基因组学、全球健康和营养领域拥有丰富的发表记录 对儿童和 PEU 动物模型的研究。他的长期目标是成为一个由 NIH 资助的独立机构 医生兼科学家研究因生命早期营养缺乏而导致的合并症。这些研究 旨在利用 PI 的儿科胃肠病学背景和 宏基因组学的研究生工作，接受了核受体生物学的新培训和高水平应用的高级应用 通量测序和生物信息分析。培训计划的其他关键要素包括： 1) A 由国际公认、独立资助的具有专业知识的研究人员组成的指导和咨询团队 开发计划的各个方面，包括 David Moore 博士。 （核受体生物学），Aleksandar 米洛萨夫列维奇博士（全基因组生物信息学）和 Robert Shulman 医学博士（临床转化研究 和儿科胃肠病学家学术职业发展）； 2) 核受体高级课程 贝勒医学院生物医学科学研究生院的生物学和生物信息学，科尔德 Spring Harbor 实验室、FASEB 科学研究会议和 Keystone 研讨会； 3）学术方面 旨在培养独立性的活动。 PI 的培训环境是一流的学术研究 与全球最大的医疗中心、全美最大的儿童医院、以及 NIH 资助的德克萨斯医学中心消化疾病中心。该环境将提供协作、 支持性和富有成效的氛围，以促进完成所有研究目标和发展目标 拟议的时间表。总之，该培训计划将使 PI 走上成功职业生涯的直接道路 作为独立研究者，同时确定 PEU 肝功能损伤的新途径 发展并最终可以预防和治疗。