Mechanistic Connection between Interorganellar Communication and Obesity-associated Diseases

细胞器间通讯与肥胖相关疾病之间的机制联系

基本信息

批准号：
10634347
负责人：
Xing Zeng
金额：
$ 42.8万
依托单位：
UT SOUTHWESTERN MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-05-01 至 2028-02-29
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10634347
关键词：
Ablation Adipocytes Adipose tissue Affect Animal Model Animals Binding Biochemical Biochemistry Biological Assay Body Weight Body mass index Brown Fat C-terminal Cardiovascular Diseases Cell model Cells Cellular biology Communication Defect Deposition Disease Dissection Elements Endocrine System Diseases Endoplasmic Reticulum Event Extravasation Genetic Models Goals Health High Fat Diet Impairment In Vitro Individual Insulin Resistance Knockout Mice Knowledge Lipid Binding Lipids Maintenance Mediating Metabolic Metabolic Diseases Mission Molecular Mus N-terminal Names National Institute of Diabetes and Digestive and Kidney Diseases Nerve Non-Insulin-Dependent Diabetes Mellitus Obesity Obesity associated disease Organ Organelles Outcome Pathogenesis Pathway interactions Persons Phenotype Phospholipids Physiological Physiology Play Population Predisposition Process Proteins Public Health Quality of life Research Risk Risk Factors Role Severities Site Structure Surface System Testing Transgenic Mice Transmembrane Domain Variant Wild Type Mouse Work density design feeding improved innovation insight metabolic phenotype mouse model nerve supply new therapeutic target non-alcoholic fatty liver disease novel obese patients reconstitution recruit therapeutic target

项目摘要

Project Summary Obesity is a leading risk factor for type 2 diabetes, nonalcoholic fatty liver disease, and cardiovascular diseases. A central driver of pathogenesis in obesity-associated disorders is the insufficient lipid-storing capacity of adipocytes and subsequent lipid deposition in extra-adipose organs. The lipid droplet (LD) is the organelle responsible for lipid storage and mobilization in adipocytes. It remains to be elucidated whether proteins and pathways regulating LD structure and function constitute limiting factors governing the lipid-storing capacity of adipocytes, and thus play an essential role in determining one’s susceptibility to obesity-associated disorders. We observed that mice deficient in CLSTN3B, a mammalian adipocyte-specific protein, are more prone to high-fat diet-induced metabolic disorders compared with body weight-matched wild-type mice, whereas the adipose-specific clstn3b transgenic mice display the opposite phenotype. Preliminary evidence shows that CLSTN3B localizes to endoplasmic reticulum (ER)/LD contact sites and ablation of CLSTN3B results in an impaired coating of LDs by phospholipids and proteins. Our overall objectives are to (i) establish the significance of CLSTN3B expressed in white adipocytes to the metabolic phenotype; (ii) reveal the molecular mechanism of CLSTN3B action at the ER/LD contact sites. The central hypothesis is that CLSTN3B enhances the structural and functional integrity of LDs, improves white adipocyte lipid-storing capacity, and contributes to the maintenance of metabolic health under obese conditions; mechanistically, this is achieved by replenishing LD surface phospholipids and promoting the binding of LD-targeting proteins. We will test this hypothesis by pursuing three specific aims: 1) Show that CLSTN3B expressed in white adipocytes is the main contributor to the metabolic benefits upon high-fat diet feeding; 2) Show that CLSTN3B promotes phospholipids transfer between ER and LD; 3) Probe the role of the C-terminal ER luminal segment of CLSTN3B in the formation of ER/LD contacts. For the first aim, we will construct genetic models allowing specific assessment of white adipocyte-derived CLSTN3B. For the second aim, we will design in vitro reconstituted phospholipid transfer assays and examine the functional significance of LD surface phospholipid density. For the third aim, we will use biochemical approaches to identify potential binding partners of the ER luminal C-terminal fragment of CLSTN3B, followed by assessing the significance of such interactions using cellular and animal models. The proposed research is innovative because it dissects the molecular mechanism of a novel protein and explains susceptibility to obesity-associated disorders from a novel perspective. The proposed research is significant because it aims to establish an integrated understanding encompassing interorganelle communication and metabolic physiology at the organismal level. Our long-term goal is to use CLSTN3B as a molecular handle to derive a thorough understanding of ER/LD interactions in the specific context of adipocytes and identify novel therapeutic targets for obesity-associated diseases.

项目概要肥胖是 2 型糖尿病、非酒精性脂肪肝和心血管疾病的主要危险因素肥胖相关疾病发病机制的一个核心驱动因素是脂质储存不足。脂肪细胞的能力和随后的脂肪外器官中的脂质沉积脂滴（LD）是脂肪细胞中负责脂质储存和动员的细胞器是否有待阐明。调节LD结构和功能的蛋白质和途径构成控制脂质储存的限制因素脂肪细胞的能力，因此在确定一个人对肥胖相关的易感性方面发挥着重要作用我们观察到，缺乏哺乳动物脂肪细胞特异性蛋白 CLSTN3B 的小鼠的患病率更高。与体重匹配的野生型小鼠相比，容易出现高脂肪饮食引起的代谢紊乱，而脂肪特异性 clstn3b 转基因小鼠则表现出相反的表型。显示 CLSTN3B 定位于内质网 (ER)/LD 接触位点以及 CLSTN3B 的消融导致磷脂和蛋白质的 LD 涂层受损。我们的总体目标是 (i) 建立。白色脂肪细胞中表达的 CLSTN3B 对代谢表型的重要性 (ii) 揭示了 CLSTN3B 在 ER/LD 接触位点作用的分子机制中心假设是 CLSTN3B。增强 LD 的结构和功能完整性，提高白色脂肪细胞的脂质储存能力，以及有助于在肥胖条件下维持代谢健康；从机制上讲，这是通过以下方式实现的；补充LD表面磷脂并促进LD靶向蛋白的结合我们将对此进行测试。通过追求三个具体目标来提出假设：1）表明白色脂肪细胞中表达的 CLSTN3B 是主要的有助于高脂肪饮食喂养的代谢益处；2) 表明 CLSTN3B 促进 ER 和 LD 之间的磷脂转移；3) 探究 ER 管腔片段 C 端的作用 CLSTN3B 参与 ER/LD 接触的形成对于第一个目标，我们将构建允许的遗传模型。对白色脂肪细胞来源的 CLSTN3B 进行具体评估对于第二个目标，我们将进行体外设计。重组磷脂转移测定并检查 LD 表面磷脂的功能意义对于第三个目标，我们将使用生化方法来识别 ER 的潜在结合伙伴。 CLSTN3B 的管腔 C 端片段，然后使用以下方法评估此类相互作用的重要性所提出的研究具有创新性，因为它剖析了分子机制。一种新蛋白质的研究，并从新的角度解释了对肥胖相关疾病的易感性。拟议的研究意义重大，因为它旨在建立一个综合的理解，涵盖我们的长期目标是在生物水平上利用细胞器间通讯和代谢生理学。 CLSTN3B 作为分子句柄，可以全面了解特定区域中 ER/LD 相互作用脂肪细胞的背景并确定肥胖相关疾病的新治疗靶点。