The Role of DENND5B in Dietary Lipid Absorption

项目摘要 餐后血浆三酰甘油水平与心血管风险独立相关 疾病。肠道在调节饮食中甘油三酯的吸收中起着关键作用 在乳胶粒中包装和分泌脂类。乳胶粒的胞内台阶 生物发生和运输已经被很好地描述了，然而，在我们的 了解肠细胞分泌乳糜粒的最后步骤的机制，特别是 高尔基体后的运输和分泌。我们最近发现了一种在这一过程中起关键作用的蛋白质。 途径，DENND5B。我们新推出的Dennd5b-/-鼠标在这方面发挥了重要作用 高尔基体基因对乳杆菌分泌囊泡质膜运输的影响。Dennd5b缺陷小鼠 对饮食引起的肥胖、血脂变化和动脉粥样硬化具有抵抗力。在人类中，外显子组 测序研究表明，一种常见的DENND5B变异与体重指数相关。这些 研究证实DENND5B在高尔基体后乳糜粒分泌和随后的 对体成分和外周脂蛋白代谢的影响。这样做的总体目标是 建议获得有关肠道吸收膳食脂肪过程的基本知识。 并检查这一过程对全身代谢健康的影响。这一目标与 美国国立卫生研究院的任务是寻求关于生命系统的基本知识，并将这些知识应用于 增进健康。这项建议的具体目的是使用我们新的小鼠模型和体外 DENND5B在肠道及其系统代谢中作用机制的实验研究 效果。目标1将量化Dennd5b对膳食脂肪吸收的影响并产生 用于检测基因网络的全面空间单细胞RNA测序数据集 参与调节膳食脂肪吸收。目标2将研究潜在的机制 Dennd5b在CM传输中的作用。此外，这一目标将使用质谱学和交互作用学 通过识别其他相互作用的蛋白质来扩大我们对这一过程的理解的分析 形成一种复合体，以促进肠道中乳糜粒的分泌。目标3将确定 Dennd5b对肠细胞代谢功能和外周脂肪代谢的影响。成功完成 这一建议将填补膳食脂肪吸收过程中的一个重大知识空白。这项工作将 通过提供乳糜粒分泌的关键步骤的机械细节来推进能量场，该步骤可以影响 全身性脂平衡与代谢健康。

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.