Fatty Acid Signaling via GPCRs in Primary Cilia Controls Adipogenesis and Insulin Secretion, Regulating Obesity and Diabetes

原发纤毛中 GPCR 的脂肪酸信号控制脂肪生成和胰岛素分泌，调节肥胖和糖尿病

基本信息

批准号：
10531880
负责人：
PETER Kent JACKSON
金额：
$ 50.41万
依托单位：
STANFORD UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-12-15 至 2024-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10531880
关键词：
Acceleration Adenylate Cyclase Adipocytes Adipose tissue Aging Agonist Antibodies B-Lymphocytes BODIPY Beta Cell Biological Assay Blood Vessels Bromodeoxyuridine CRISPR screen Calcium Cells Cilia Cyclic AMP Diabetes Mellitus Dinoprostone Disease Progression Dyes Early identification Event FFAR1 gene Fatty Acids Fatty acid glycerol esters Formulation G Protein-Coupled Receptor Signaling G-Protein-Coupled Receptors Gender Genes Genetic Glucagon Glucose Glucose Intolerance Growth Growth Factor High Fat Diet Histologic Hormones Human Human Genetics Hypertrophy Hypoxia IGF1 gene In Vitro Inflammation Inflammatory Insulin Insulin Resistance Islets of Langerhans Knock-out Knockout Mice Ligands Link Lipid Inclusion Lipids Mesenchymal Metabolic Metabolism Modeling Mus Nutritional Obesity Omega-3 Fatty Acids Organism Pathway interactions Patients Pharmacology Platelet-Derived Growth Factor alpha Receptor Production Prostaglandin E Receptor Prostaglandins Proteomics Publishing Regulation Reporter S phase Saturated Fatty Acids Sex Differences Signal Pathway Signal Transduction Structure of beta Cell of islet System Tamoxifen Testing Tissue Expansion Tissues Translation Initiation Translations adipocyte differentiation adult stem cell cell type diabetic diabetic patient dietary differentiation protocol feeding genetic testing genome wide screen genome-wide glucagon-like peptide 1 human disease immune activation improved insulin secretion insulin signaling insulinoma islet lipid biosynthesis mouse model multiple omics obese patients phosphoric diester hydrolase programs receptor sensor stem cell population stem cells synergism therapeutically effective trafficking

项目摘要

This project focuses on understanding how dietary fluxes from w-3 fatty acids activate the FFAR4 receptor, expressed in primary cilia, in both preadipocytes to trigger adipogenesis and in pancreatic b cells to enhance insulin secretion. The proposal extends from a recent discovery in the Jackson lab of a dramatic requirement for primary cilia in de novo adipogenesis and for the accumulation of fat mass in mice (Cell 2019). Using a knockout of TULP3, a critical regulator of ciliary GPCR trafficking, the group has established a requirement for ciliary GPCR signaling and screened 36 candidates to discover that the w-3 fatty acid (FA) receptor FFAR4/GPR120 is critical. Using FFAR4 and ciliary markers, the group finds that ciliated FFAR4+ preadipocytes comprise a perivascular stem cell population in all fat pads. Further, DHA-FFAR4 signaling synergizes with insulin signaling to direct adipogenic fate change and that FFAR4 agonists rapidly activate localized cAMP in the cilium. To better define the steps in adipogenesis downstream of FFAR4, two genome-wide CRISPR screens for genes important in adipogenesis were conducted, one using a traditional adipogenesis formulation and the other activated by FFAR4 agonists. These screens recapitulated most known requirements for adipogenesis and provided a wealth of new genes important for the adipogenic program. Among these there is a strong requirement for new factors controlling translation initiation and cap-independent translation. Finally, looking for the importance of FFAR4 in other metabolic systems, the group discovered that all pancreatic islet cell types are ciliated, but that both b and a cells express FFAR4 in cilia. Detailed pharmacology and genetics show that FFAR4 agonists can drive glucose stimulated insulin secretion (GSIS) in isolated b cells or islets at levels comparable to known secretagogues like GLP-1. FFAR4 agonists also stimulate glucagon secretion in a cells. Both effects require ciliary trafficking. The first Aim will focus on validating and explaining new adipogenesis factors found in the screen. This will focus on identifying specific adenylate cyclases, phosphodiesterases, cAMP effectors, and translational control genes. Aim 2 will focus on FFAR4 signaling in pancreatic b cells to understand the mechanisms of how FFAR4 and cAMP drive insulin secretion and how another w-3 fatty acid receptor, FFAR1, drives calcium influx to cooperate with FFAR4. Finally, in Aim 3, the focus is to use mouse models systematically knocking out both FFAR4 and FFAR1 to examine the cooperation of these pathways in obesity, insulin secretion and diabetes. This aim will also examine human patient adipose tissue to determine if FFAR4+ ciliary in preadipocytes are lost in aging, diabetic or obese patients, also comparing sex differences. Overall, Aim 3 will test whether FFAR4 or ciliary loss is an important driver of diabetic disease progression, setting up critical tests of FFAR4 and other GPCRs for normalizing adipogenesis and improving insulin secretion in aging, diabetic patients.

该项目的重点是了解 w-3 脂肪酸的膳食通量如何激活 FFAR4 受体，在初级纤毛中表达，在前脂肪细胞中表达以触发脂肪生成，在胰腺 b 细胞中表达以增强胰岛素分泌。该提案源于杰克逊实验室最近的一项发现，即小鼠脂肪从头生成和脂肪量积累对初级纤毛的巨大需求（Cell 2019）。通过敲除睫状 GPCR 运输的关键调节因子 TULP3，该小组确定了睫状 GPCR 信号传导的要求，并筛选了 36 个候选者，发现 w-3 脂肪酸 (FA) 受体 FFAR4/GPR120 至关重要。使用 FFAR4 和纤毛标记，研究小组发现纤毛 FFAR4+ 前脂肪细胞构成所有脂肪垫中的血管周围干细胞群。此外，DHA-FFAR4 信号传导与胰岛素信号传导协同作用，以指导脂肪形成命运的改变，并且 FFAR4 激动剂快速激活纤毛中的局部 cAMP。为了更好地确定 FFAR4 下游脂肪生成的步骤，对脂肪生成中重要的基因进行了两次全基因组 CRISPR 筛选，一次使用传统的脂肪生成制剂，另一次由 FFAR4 激动剂激活。这些屏幕概括了大多数已知的要求并提供了大量对脂肪形成程序重要的新基因。其中强烈需要控制翻译起始和与帽无关的翻译的新因素。最后，在寻找 FFAR4 在其他代谢系统中的重要性时，该小组发现所有胰岛细胞类型都有纤毛，但 b 细胞和 a 细胞在纤毛中都表达 FFAR4。详细的药理学和遗传学表明，FFAR4 激动剂可以在分离的 b 细胞或胰岛中驱动葡萄糖刺激的胰岛素分泌 (GSIS)，其水平与已知的促分泌剂（如 GLP-1）相当。 FFAR4 激动剂还刺激细胞中的胰高血糖素分泌。这两种效果都需要纤毛运输。第一个目标将侧重于验证和解释屏幕中发现的新脂肪生成因子。这将重点鉴定特定的腺苷酸环化酶、磷酸二酯酶、cAMP 效应子和翻译控制基因。目标 2 将重点关注胰腺 b 细胞中的 FFAR4 信号传导，以了解 FFAR4 和 cAMP 如何驱动胰岛素分泌以及另一种 w-3 脂肪酸受体 FFAR1 如何驱动钙流入以与 FFAR4 配合的机制。最后，目标 3 的重点是使用系统敲除 FFAR4 和 FFAR1 的小鼠模型来检查这些途径在肥胖、胰岛素分泌和糖尿病中的协同作用。该目标还将检查人类患者的脂肪组织，以确定前脂肪细胞中的 FFAR4+ 纤毛是否在衰老、糖尿病或肥胖患者中丢失，并比较性别差异。总体而言，目标 3 将测试 FFAR4 或纤毛丢失是否是糖尿病疾病进展的重要驱动因素，建立 FFAR4 和其他 GPCR 的关键测试，以使脂肪生成正常化并改善老年糖尿病患者的胰岛素分泌。