Physiological and Pathological Aspects of Intestinal Vitamin B2 Absorption

肠道维生素 B2 吸收的生理和病理方面

• 批准号: 9215519
• 负责人: HAMID M SAID
• 金额: --
• 依托单位: VETERANS HEALTH ADMINISTRATION
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2020-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9215519
• 关键词: Acyl CoA Dehydrogenases; Affect; Alcoholism; Alcohols; Anti-Inflammatory Agents; Anti-inflammatory; Antioxidants; Apical; Biological; Carbohydrates; Cells; Cellular biology; Chronic; Clinical; Colon; Disease; Docking; Enterocytes; Epigenetic Process; Epithelial Cells; Event; Exposure to; Fazio-Londe Syndrome; Folic Acid; Functional disorder; Funding; Gene Silencing; Genes; Genetic Transcription; Grant; Health; Homeostasis; Homology Modeling; Human; In Vitro; Inborn Genetic Diseases; Infection; Inflammatory; Inflammatory Bowel Diseases; Injury; Intestinal Absorption; Intestines; Investigation; Ischemia; Knockout Mice; Laboratories; Lead; Ligands; Lipids; Maintenance; Mammals; Mediating; Metabolic; Metabolism; MicroRNAs; Micronutrients; Molecular; Mutation; Oxidation-Reduction; Pathologic; Patients; Physiological; Physiology; Play; Post-Transcriptional Regulation; Process; Property; Proteins; Publishing; Regulation; Riboflavin; Role; Salmonella enterica; Salmonella infections; Serotyping; Small Interfering RNA; Small Intestines; Source; Testing; Tissues; Vitamin B6; Vitamins; Work; absorption; acyl-CoA dehydrogenase; alcohol effect; alcohol exposure; amino acid metabolism; base; cytokine; design; enteric pathogen; feeding; immune function; in vivo; intestinal homeostasis; mouse model; negative affect; novel; public health relevance; uptake; Acyl CoA Dehydrogenases; Affect; Alcoholism; Alcohols; Anti-Inflammatory Agents; Anti-inflammatory; Antioxidants; Apical; Biological; Carbohydrates; Cells; Cellular biology; Chronic; Clinical; Colon; Disease; Docking; Enterocytes; Epigenetic Process; Epithelial Cells; Event; Exposure to; Fazio-Londe Syndrome; Folic Acid; Functional disorder; Funding; Gene Silencing; Genes; Genetic Transcription; Grant; Health; Homeostasis; Homology Modeling; Human; In Vitro; Inborn Genetic Diseases; Infection; Inflammatory; Inflammatory Bowel Diseases; Injury; Intestinal Absorption; Intestines; Investigation; Ischemia; Knockout Mice; Laboratories; Lead; Ligands; Lipids; Maintenance; Mammals; Mediating; Metabolic; Metabolism; MicroRNAs; Micronutrients; Molecular; Mutation; Oxidation-Reduction; Pathologic; Patients; Physiological; Physiology; Play; Post-Transcriptional Regulation; Process; Property; Proteins; Publishing; Regulation; Riboflavin; Role; Salmonella enterica; Salmonella infections; Serotyping; Small Interfering RNA; Small Intestines; Source; Testing; Tissues; Vitamin B6; Vitamins; Work; absorption; acyl-CoA dehydrogenase; alcohol effect; alcohol exposure; amino acid metabolism; base; cytokine; design; enteric pathogen; feeding; immune function; in vivo; intestinal homeostasis; mouse model; negative affect; novel; public health relevance; uptake

 DESCRIPTION (provided by applicant): The long-term objectives of this renewal application continue to focus on investigating the cell/molecular physiology and pathophysiology of the intestinal vitamin B2 (riboflavin; RF) uptake process and of the factors that affect and interfere with the event. RF is essential for normal human health due to the key roles it plays in biological oxidation-reduction reactions involving lipid, carbohydrate and amino acid metabolism, and in the conversion of vitamin B6 and folate into their active forms. Recent findings have uncovered additional roles for RF in normal immune function, as an anti-inflammatory and anti-oxidant agent, and in the maintenance of normal intestinal homeostasis. Humans (mammals) cannot synthesize RF, and thus, must obtain the vitamin from exogenous sources via intestinal absorption. Studies from our laboratory and others have characterized different aspects of intestinal RF absorption and shown the process is specific and carrier-mediated; also all the three recently cloned RFVTs (RFVT-1, -2 & -3; products of the SLC52A1, SLC52A2 & SLC52A3 genes, respectively) are expressed in the intestine. In studies performed during the current funding period, we used an in vitro gene-silencing (siRNA) approach to show that the apically expressed RFVT-3 plays a major role in intestinal RF uptake. In new preliminary studies aimed at establishing the role of RFVT-3 in intestinal RF absorption in native intestine in vivo, we generated a conditional (intestinal-specific) SLC52A3 knockout (KO) mouse model and plan to use it to confirm and extend our in vitro findings. In other new preliminary studies, we have identified (via homology modeling/ligand docking analyses) putative structural features in the RFVT-3 protein that may be important for its function, obtained evidence implicating microRNAs (miRNAs) in post-transcriptional regulation of intestinal RF uptake, and have identified several potential interactig partners with RFVT-3 in intestinal epithelial cells. We also obtained evidence showing that infection of intestinal epithelial cells with S. Typhimurium, and exposure to pro-inflammatory cytokines and to bacterial LPS significantly lead to inhibition in intestinal RF uptake. Finally, w obtained new preliminary evidence suggesting possible involvement of epigenetic mechanism(s) in the inhibitory effect of chronic alcohol feeding on intestinal/colonic RF uptake that we observed during the current funding period. Based on our published studies and new preliminary findings, our working hypotheses in this proposal are that: 1) the RFVT-3 plays an important role in RF absorption in native intestine in vivo; that the transporter is post-transcriptionally regulated by microRNA; and that it has interacting partner(s) that may influence its physiology/cell biology; 2) Salmonella infection, and exposure to pro-inflammatory cytokines and to bacterial LPS inhibits intestinal RF uptake; and 3) the inhibitory effect of chronic alcohol exposure on SLC52A3 transcription in the intestine is mediated, at least in part, via epigenetic/molecular mechanism(s). Three specific aims are proposed to test these hypotheses and will utilize state-of-the-art in vivo and in vitro physiological, cellular, and molecular approaches. Results of these studies should continue to provide novel and valuable information regarding the cell/molecular physiology and pathophysiology of intestinal RF uptake and of external factors that affect and interfere with the process. This should ultimately assist us in th designing of effective strategies to optimize RF body homeostasis, especially in conditions associated with RF deficiency and sub-optimal levels.

 描述（由申请人提供）： 该更新应用的长期目标继续集中于研究肠道维生素B2（核黄素； RF）摄取过程的细胞/分子生理学和病理生理学以及影响事件和影响事件的因素。 RF对于正常的人类健康至关重要，因为它在涉及脂质，碳水化合物和氨基酸代谢的生物氧化还原反应中起着关键作用，以及将维生素B6和叶酸转化为活性形式。最近的发现已经发现了RF在正常免疫功能中的其他作用，作为一种抗炎和抗氧化剂，以及维持正常肠稳态的作用。人（哺乳动物）无法合成RF，因此必须通过肠道抽象从外源来源获得维生素。我们的实验室和其他人的研究表征了肠道RF抽象的不同方面，并表明该过程是特定的，并且是载体介导的。同样，所有最近克隆的RFVT（RFVT -1，-2＆-3; SLC52A1，SLC52A2和SLC52A3基因分别）在肠中表达。在当前资金期间进行的研究中，我们使用了体外基因沉默（siRNA）方法，表明顶尖表达的RFVT-3在肠RF摄取中起着重要作用。在新的初步研究中，旨在确定RFVT-3在体内天然肠受损中的作用，我们产生了条件（肠道特异性）SLC52A3敲除（KO）小鼠模型并计划使用它来确认和扩展我们的体外发现。在其他新的初步研究中，我们已经在RFVT-3蛋白中鉴定出（通过同源性模型/配体对接分析）推定的结构特征，这可能对其功能很重要，在肠道后RF的转录后调节中，获得了证据隐式microRNAS（miRNA），并确定了与RFVT-3 Intselig partners int int int int int int int int int int int int int int int int int inT3中。我们还获得了证据表明，肠上皮细胞用伤寒链霉菌感染，暴露于促炎细胞因子和细菌LPS的感染显着导致肠道RF摄取的抑制作用。最后，W获得了新的初步证据，表明表观遗传机制可能参与了我们在当前资助期间观察到的慢性酒精喂养对肠道/结肠RF摄取的抑制作用。基于我们发表的研究和新的初步发现，我们在该提案中的工作假设是：1）RFVT-3在体内天然肠受苦中起重要作用；转运蛋白在转录后由microRNA调节；并具有可能影响其生理/细胞生物学的相互作用伴侣； 2）沙门氏菌感染，并暴露于促炎性细胞因子和细菌LPS抑制肠RF摄取； 3）慢性酒精的抑制作用 在肠中SLC52A3转录上的暴露至少部分通过表观遗传/分子机制介导。提出了三个特定的目的来检验这些假设，并将利用体内和体外生理，细胞和分子方法的最先进。这些研究的结果应继续提供有关肠道RF摄取的细胞/分子生理学和病理生理学的新颖和有价值的信息，以及影响和干扰该过程的外部因素。最终，这应该有助于我们设计有效的策略来优化RF身体体内稳态，尤其是在与RF缺乏症和亚最佳水平相关的条件下。