The Role of DENND5B in Dietary Lipid Absorption

项目摘要 餐后血浆甘油三酯水平与心血管疾病风险独立相关 疾病肠道在调节膳食甘油三酯吸收中起着关键作用， 在乳糜微粒中包装和分泌脂质。乳糜微粒的细胞内步骤 生物起源和运输已经得到了相当好的描述，然而，在我们的研究中存在着重大的差距。 了解肠细胞分泌乳糜微粒的最后步骤的机制，特别是 后高尔基体运输和分泌。我们最近发现了一种蛋白质， 途径，DEND 5 B。我们新生成的Dennd 5 b-/-小鼠在这方面发挥了重要作用 基因在高尔基体的质膜转运乳糜微粒分泌囊泡。Dennd 5 b缺陷小鼠 对饮食引起的肥胖、血脂变化和动脉粥样硬化有抵抗力。在人类中， 测序研究显示，一种常见的DENND 5 B变异体与体重指数相关。这些 研究确定DENND 5 B在高尔基体后乳糜微粒分泌中的重要作用， 对身体组成和外周脂蛋白代谢影响。本报告的总体目标 建议是获得有关肠道吸收膳食脂质过程的基础知识 并检查这一过程对全身代谢健康的影响。这一目标与以下目标完全一致： NIH的使命是寻求有关生命系统的基本知识，并将这些知识应用于 增进健康。本提案的具体目的是使用我们的新型小鼠模型和体外 研究DENND 5 B在肠道及其全身代谢中的机制作用的实验 方面的影响.目的1将量化Dennd 5 b对膳食脂质吸收的影响，并产生一个 全面的空间单细胞RNA测序数据集，用于检查基因网络， 参与调节膳食脂肪的吸收。目标2将研究 CM运输中的Dennd 5 b作用。此外，这一目标将使用质谱和相互作用组学 分析，以扩大我们对这一过程的理解，通过确定其他相互作用的蛋白质， 形成复合物以促进肠分泌乳糜微粒。目标3将决定 dennd 5 b对肠上皮细胞代谢功能和外周脂质代谢的影响。成功完成 这一建议将填补膳食脂肪吸收过程中的重大知识空白。这项工作将 通过提供乳糜微粒分泌的关键步骤的机制细节来推进该领域， 全身脂质稳态和代谢健康。

Project Summary Postprandial plasma triacylglyceride levels are independently associated with risk of cardiovascular disease. The intestine plays a key role in the regulation of dietary triacylglyceride absorption by packaging and secreting lipids in chylomicron particles. The intracellular steps of chylomicron biogenesis and transport have been fairly well described, however, there is a significant gap in our understanding of the mechanism for the final steps of chylomicron secretion by enterocytes, specifically post-Golgi transport and secretion. We recently identified a protein that plays a critical role in this pathway, DENND5B. Our newly generated Dennd5b-/- mouse demonstrates an essential role for this gene in Golgi to plasma membrane transport of chylomicron secretory vesicles. Dennd5b-deficient mice are resistant to diet-induced: obesity, changes in plasma lipids, and atherosclerosis. In humans, exome sequencing studies reveal that a common DENND5B variant is correlated with body mass index. These studies establish an important role for DENND5B in post-Golgi chylomicron secretion and a subsequent influence on body composition and peripheral lipoprotein metabolism. The overall objective of this proposal is to gain fundamental knowledge about the process of dietary lipid absorption by the intestine and to examine the impact of this process on systemic metabolic health. This objective aligns well with the NIH mission to seek fundamental knowledge about living systems and to apply this knowledge to enhance health. The Specific Aims of this proposal use our novel mouse model and in vitro experiments to examine the mechanistic role of DENND5B in the intestine and its systemic metabolic effects. Aim 1 will quantify the impact of Dennd5b on dietary lipid absorption and generate a comprehensive spatial single-cell RNAsequencing data set for examination of gene networks that participate in regulation of dietary lipid absorption. Aim 2 will examine the mechanism underlying Dennd5b action in CM transport. Furthermore, this aim will use mass spectrometry and interactomics analysis to expand our understanding of this process by identifying other interacting proteins which may form a complex to facilitate chylomicron secretion by the intestine. Aim 3 will determine the impact of Dennd5b on enterocyte metabolic function and peripheral lipid metabolism. Successful completion of this proposal will fill a significant knowledge gap in the process of dietary lipid absorption. This work will advance the field by providing mechanistic details for a key step in chylomicron secretion that can affect systemic lipid homeostasis and metabolic health.