Examining the role of LDLR in the biodistribution of carotenoids

项目总结 低密度脂蛋白受体(LDLR)是一种广泛表达的蛋白质，主要因其在肝脏中的作用而闻名。 低密度脂蛋白胆固醇的摄取和清除。和胆固醇一样，类胡萝卜素，如β-胡萝卜素和叶黄素 由于其疏水性，在低密度脂蛋白颗粒中运输。然而，仍然有未知的关于 脂蛋白中类胡萝卜素的代谢命运，以及LDLR在这些过程中的作用。在……里面 特别是，已知低密度脂蛋白受体调节肠道胆固醇的排泄，这已知占高达 人类体内35%的胆固醇排泄量。类胡萝卜素是否也通过这个过程被消除是 未知。类胡萝卜素主要储存在肝脏中，但令人惊讶的是，在 类胡萝卜素的肝脏代谢，包括LDLR是否介导肝脏对类胡萝卜素的摄取，或者如果 类胡萝卜素和胆固醇一样，会改变极低密度脂蛋白颗粒中分泌的特性。因此，最重要的是 这项建议的目的是表征LDLR在类胡萝卜素排泄和肝脏摄取中的作用。 检查类胡萝卜素在极低密度脂蛋白颗粒中的掺入情况，以及极低密度脂蛋白的特征如何因此而 被更改了。我们假设低密度脂蛋白受体调节肠道内类胡萝卜素的排泄并对肝脏有贡献。 类胡萝卜素摄取。我们还假设肝脏类胡萝卜素被结合到新合成的极低密度脂蛋白中。 并改变它们的大小和脂肪含量。为了检验这些假设，我们提出了三个目标 描述LDLR参与类胡萝卜素的摄取和排泄，以及肝脏参与 类胡萝卜素分布。这些研究有可能揭示类胡萝卜素运输和 在人类身上消除。

PROJECT SUMMARY The low-density lipoprotein receptor (LDLR) is a widely expressed protein known mostly for its role in hepatic uptake and clearance of LDL cholesterol. Like cholesterol, carotenoids such as β-carotene and lutein are transported in LDL particles due to their hydrophobic nature. There remains, however, unknowns about the metabolic fate of carotenoids found in lipoproteins, as well as the function of LDLR in these processes. In particular, LDLR is known to mediate transintestinal cholesterol excretion, which is known to account for up to 35% of cholesterol excretion in humans. Whether carotenoids are also eliminated through this process is unknown. Carotenoids are primarily stored in the liver, but surprisingly, several knowledge gaps exist in the hepatic metabolism of carotenoids, including if LDLR mediates the hepatic uptake of carotenoids, or if carotenoids, like cholesterol, modify the characteristics of secreted in VLDL particles. Therefore, the overarching objective of this proposal is to characterize the role of LDLR in carotenoid excretion and hepatic uptake, as well as examine the incorporation of carotenoids into VLDL particles and how VLDL characteristics are consequently altered. We hypothesize that LDLR mediates transintestinal carotenoid excretion and contributes to hepatic carotenoid uptake. We also hypothesize that hepatic carotenoids are incorporated into newly-synthesized VLDL and modify their size and lipid content. To test these hypotheses, we propose three objectives that will characterize the involvement of LDLR in carotenoid uptake and excretion, as well as hepatic participation in carotenoid distribution. These studies have the potential to reveal critical pathways in carotenoid transport and elimination in humans.