Functional & molecular study of intetinal cholesterol transporters & absorption

功能性

基本信息

批准号：
7314490
负责人：
PATRICK TSO
金额：
$ 31.98万
依托单位：
UNIVERSITY OF CINCINNATI
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-08-01 至 2012-07-31
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): 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.

描述（由申请人提供）：Zetia（Ezetimibe）通过抑制肠细胞中NPC1-L1介导的胆固醇转运途径（S）来抑制胆固醇的吸收。我们证明CD36在胆固醇吸收中也起作用。还证明，清道夫受体SR-BI是肠道边界膜上的另一种推定胆固醇转运蛋白。我们假设SR-BI和CD36分别是近端和远端肠道中的胆固醇转运蛋白，与NPC1-L1（可能是细胞内）一起工作，可介导从腔内到肠内细胞内肠细胞内的胆固醇摄取的胆固醇吸收。 AIM 1：我们将确定：1）缺乏SR-BI，CD36或NPC1L1是否会改变吸收胆固醇的位点和/或效率（通过改变位点或输注剂量）； 2）如果在没有一种或另一种转运蛋白蛋白的情况下将对应物转运蛋白上调以维持胆固醇的吸收。在淋巴瘘小鼠中，我们还将确定ezetimibe是否在这些敲除动物中小肠抑制胆固醇的摄取能力是否仍然有效。 AIM 2：首先，我们将确定ezetimibe的替代剂量是否结合了乌索焦麦酸酸盐或pluronic F-68（F-68）的副作用剂量，抑制大鼠中肠道胆固醇的吸收。另外，我们将确定相同的现象在小鼠中也起作用。其次，在上述敲除小鼠模型中，我们将确定单独或组合ezetimibe或Ursodoxyoxycyaly或F-68是否有效地抑制小肠抑制胆固醇的吸收。目的3：我们将利用埃泽略比抑制肠道胆固醇的能力，以及pluronic L-81防止形成酪液形成的能力，以识别途径并量化肠皮细胞通过肠胃外的胆固醇的量，并通过基底层属植物质量lip lip lip lip lip-lip lip lip lip-lip-lip-lip-lip-lip-lip-lip-lip-lip-lip lip lip。使用ezetimibe和Pluronic L-81的组合，我们将能够研究小肠对胆固醇的摄取和外排。拟议研究的完成将为我们提供有关胆固醇摄取和淋巴运输如何受肠道中各种转运蛋白的调节的新见解。这些新数据还可能为我们提供高胆固醇患者的临床管理中的新信息。