Functional & molecular study of intetinal cholesterol transporters & absorption

功能性

• 批准号: 7896869
• 负责人: PATRICK TSO
• 金额: $ 7.35万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-15 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7896869
• 关键词: Animals; Anticholesteremic Agents; Apical; CD36 gene; Carrier Proteins; Cholesterol; Chylomicrons; Clinical Management; Data; Detergents; Distal; Dose; Enterocytes; Fistula; In Vitro; Infusion procedures; Intestines; Knock-out; Knockout Mice; Laboratories; Lipoproteins; Location; Lymph; Lymphatic; Mediating; Molecular; Mus; Pathway interactions; Patients; Play; Pluronic F-68; Pluronic L81; Property; Proteins; Rattus; Reporting; Research Personnel; Role; Schering-Plough brand of ezetimibe; Side; Site; Small Intestines; Structure; Testing; Triglycerides; Work; Writing; absorption; basolateral membrane; bile salts; brush border membrane; cholesterol absorption; cholesterol trafficking; cholesterol transporters; ezetimibe; feeding; in vivo; insight; knockout animal; mouse model; prevent; programs; scavenger receptor; uptake; ursodeoxycholate

Zetia (Ezetimibe) inhibits cholesterol absorption via inhibition of NPC1-L1 mediated cholesterol transport pathway(s) in the enterocytes. We demonstrated that CD36 also plays a role in cholesterol absorption. It has also been demonstrated that the scavenger receptor SR-BI as another putative cholesterol transporter on intestinal brush border membrane. We hypothesize that SR-BI and CD36 are cholesterol transporters in the proximal and distal intestine, respectively, working in conjunction with NPC1-L1 (may be intracellular) to mediate cholesterol uptake from the lumen to intracellular compartments of the enterocytes where chylomicron assembly occurs. Aim 1: We will determine: 1) if the lack of SR-BI, CD36, or NPC1L1 alters the site and/or efficiency of cholesterol absorption (by varying the site or dose of infusion); and 2) if the counterpart transporters are upregulated to maintain cholesterol absorption in the absence of one or the other transporter protein. In lymph fistula mice, we will also determine if Ezetimibe remains effective in inhibiting cholesterol uptake by the small intestine in these knockout animals. Aim 2: First, we will determine if sub-effective doses of Ezetimibe, in combination with sub-effective doses of either ursodeoxycholate or Pluronic F-68 (F-68), inhibits intestinal cholesterol absorption in the rat. Also, we will determine the same phenomenon also works in the mouse. Second, in the knockout mice models described above, we will determine if Ezetimibe or ursodeoxycholate or F-68 alone or in combination is/are effective in inhibiting cholesterol absorption by the small intestine. Aim 3: We will take advantage of the ability of Ezetimibe to inhibit intestinal cholesterol, and the ability of Pluronic L-81 to prevent chylomicron formation to identify the pathway and quantify the amount of cholesterol exiting the enterocytes through efflux to the apical side as well as secreted through the basolateral membrane as triglyceride-rich lipoproteins. Using a combination of both Ezetimibe and Pluronic L-81, we will be able to study both the uptake and efflux of cholesterol by the small intestine. Completion of the proposed studies will provide us with new insights into how cholesterol uptake and lymphatic transport are regulated by the various transporters in the gut. These new data may also provide us with new information in the clinical management of hypercholestermic patients.

Zetia（ezetimibe）通过抑制NPC1-L1介导的胆固醇转运来抑制胆固醇的吸收 肠肠细胞中的途径。我们证明CD36在胆固醇吸收中也起作用。它 还证明了清道夫受体SR-BI作为另一个推定的胆固醇转运蛋白 在肠道边界膜上。我们假设SR-BI和CD36是胆固醇转运蛋白 分别与NPC1-L1（可能是细胞内）一起工作的近端和远端肠道 介导胆固醇从管腔摄取到肠内细胞的细胞内隔室，其中 发生乳糜微粒装配。目标1：我们将确定：1）是否缺乏SR-BI，CD36或NPC1L1改变 胆固醇吸收的位点和/或效率（通过改变位点或输注剂量）； 2）如果 对应物转运蛋白被上调以在没有一个或一个的情况下保持胆固醇的吸收 其他转运蛋白。在淋巴瘘小鼠中，我们还将确定ezetimibe是否在 在这些淘汰动物中，小肠抑制胆固醇的摄取。目标2：首先，我们将确定 如果依泽替米贝剂量降低，则与厄去氧化胆汁酸盐或 Pluronic F-68（F-68）抑制大鼠肠道胆固醇的吸收。另外，我们将确定相同的 现象在鼠标中也起作用。第二，在上述敲除小鼠模型中，我们将 确定单独的ezetimibe或Ursodoxyoxycyaly或F-68或组合是否有效抑制 小肠吸收胆固醇。目标3：我们将利用ezetimibe的能力 抑制肠道胆固醇，以及pluronic L-81防止乳糜微粒形成的能力 途径并量化通过外排向肠上皮细胞向根尖侧流出的胆固醇的量 并通过基底外侧膜分泌为富含甘油三酸酯的脂蛋白。结合 ezetimibe和Pluronic L-81，我们将能够研究胆固醇的摄取和外排 小肠。拟议研究的完成将为我们提供有关胆固醇如何的新见解 摄取和淋巴运输受肠道中的各种转运蛋白的调节。这些新数据可能 还为我们提供了高胆固醇患者的临床管理中的新信息。