Metabolic Reprogramming by Protease-activated Receptor 2

蛋白酶激活受体 2 的代谢重编程

• 批准号: 10365793
• 负责人: ATHAN KULIOPULOS
• 金额: $ 58.74万
• 依托单位: TUFTS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-02-15 至 2024-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10365793
• 关键词: Adipose tissue; Affect; American; Applications Grants; Biochemical; Body Weight decreased; Carbon; Cell membrane; Cholesterol; Cholesterol Homeostasis; Cirrhosis; Clinical Data; Coagulation Process; Consumption; Coupled; Cross-Sectional Studies; Data; Dyslipidemias; Etiology; Extracellular Domain; Fatty Liver; Fatty acid glycerol esters; Fibrosis; G-Protein-Coupled Receptors; GLUT-2 protein; GTP-Binding Proteins; Glucose; Glucose Transporter; Glycogen; Goals; Hepatic; Hepatocyte; Human; Hypertriglyceridemia; In Vitro; Inflammation; Insulin; Insulin Resistance; Intestines; Knock-out; Knockout Mice; LDL Cholesterol Lipoproteins; Lead; Ligands; Link; Liver; Liver Fibrosis; Liver diseases; MAP Kinase Gene; Mediating; Membrane; Metabolic; Metabolic Pathway; Metabolism; Modeling; Mus; N-terminal; Names; Non-Insulin-Dependent Diabetes Mellitus; Obese Mice; Obesity; Obesity Epidemic; PAR-1 Receptor; PAR-2 Receptor; Pathogenesis; Pathology; Pathway interactions; Patients; Peptide Hydrolases; Phenotype; Pilot Projects; Plasma; Primary carcinoma of the liver cells; Proteinase-Activated Receptors; Proto-Oncogene Proteins c-akt; Ramp; Role; SRE-2 binding protein; Signal Pathway; Signal Transduction; Site; Specimen; Surface; Technology; Testing; Therapeutic Intervention; Thinness; Tissues; Trypsin; United States National Institutes of Health; Validation; Visceral; antagonist; beta-arrestin; blood glucose regulation; cell type; cohort; diabetic; diet-induced obesity; effective therapy; fatty liver disease; glycogenesis; hypercholesterolemia; in vivo; lipid metabolism; liver biopsy; liver metabolism; liver transplantation; macrophage; mortality; mouse model; non-alcoholic fatty liver disease; nonalcoholic steatohepatitis; novel; protein expression; receptor; release of sequestered calcium ion into cytoplasm; resistance mechanism; reverse cholesterol transport; sugar

Excessive sugar and fat consumption can lead to a range of metabolic abnormalities including non-alcoholic fatty liver disease (NAFLD), hypercholesterolemia, dyslipidemia, obesity, and insulin resistance. Emerging evidence points to a new mechanism linking carbon metabolism and fatty liver disease to the G protein-coupled Protease Activated Receptor-2 (PAR2), a receptor previously known to be involved in inflammation. To provide key support for the potential importance of hepatic PAR2 in humans, in a cross-sectional study of liver specimens and clinical data from 108 NAFLD patients and controls, we found that PAR2 protein expression in hepatocytes was low in control livers and progressively increased in patients with mild NAFLD fibrosis and in NAFLD with higher stages of fibrosis. The high PAR2-expressing NAFLD patient cohort had significantly elevated plasma LDL cholesterol as compared to the low PAR2-expressing cohort. However, a definitive role for PAR2 in metabolism, cholesterol homeostasis, and liver pathology remains unknown. The overarching goal of this grant proposal is to examine the role of PAR2 signaling in the etiology and pathogenesis of fatty liver disease to test our central hypothesis that hepatic PAR2 is a novel contributor of hypertriglyceridemia, obesity, and insulin resistance. PAR2 is expressed by many tissues and cell types and a conventional mouse whole-body knockout (KO) has been used to date. Therefore, it is unclear how much of the KO phenotype or effects of PAR2 inhibition on steatosis, lipid metabolism, and weight loss is mediated only at the level of the hepatocyte and how much is due to loss of PAR2 at other sites of expression. We will use our new hepatocyte-specific PAR2-KO, PAR2∆Hep mice to define and validate the specific involvement of liver PAR2 in these profound metabolic effects in aims 1-3. It is unclear how PAR2 promotes insulin resistance in diet-induced obesity models. Aim 2 will explore a novel mechanism whereby PAR2 activates a Gq-PLC pathway to stimulate calcium flux and CaMKK2 to interfere in insulin activation of AKT-glucose signaling. To explain our preliminary data that global PAR2-deficiency lowers basal plasma glucose, but increases liver glucose and glycogen in both lean and obese mouse models, Aim 3 will test the hypothesis that hepatocyte PAR2 suppresses the major liver glucose transporter GLUT2 through a mechanism potentially involving Gq-MAPK-FoxA3. Aims 1-3 will utilize our pepducin technology developed to allosterically target G-protein coupled receptors on the inside surface of the plasma membrane to help delineate specific PAR2-effector signaling pathways in aberrant liver metabolism and insulin resistance in vitro and in vivo.

过量的糖和脂肪消耗会导致一系列代谢异常，包括非酒精性脂肪肝病（NAFLD），高胆固醇血症，血脂异常，肥胖和胰岛素抵抗。新兴的证据指出了一种新的机制，将碳代谢和脂肪肝病与G蛋白偶联蛋白酶激活受体-2（PAR2）联系起来，这是一种以前已知参与炎症的受体。为了为人类肝PAR2在人类中的潜在重要性提供重要的支持，在对108名NAFLD患者和对照组的肝脏标本和临床数据的横断面研究中，我们发现，对照肝脏中的PAR2蛋白表达在对照肝脏中较低，并且在轻度NAFLD纤维化和NAFLD的患者中逐渐增加，并且具有纤维化较高的患者。与低表达PAR2的队列相比，表达高PAR2的NAFLD患者队列的血浆LDL胆固醇显着升高。但是，PAR2在代谢，胆固醇稳态和肝病病理学中的明确作用仍然未知。该赠款提案的总体目标是检查PAR2信号传导在脂肪肝病病因和发病机理中的作用，以检验我们的中心假设，即肝par2是高甘油三酸酯，肥胖和胰岛素抵抗的新促成者。 PAR2由许多组织和细胞类型表达，并且迄今已使用了常规的小鼠全身敲除（KO）。因此，尚不清楚PAR2抑制对脂肪变性，脂质代谢和体重减轻的抑制作用的多少或仅在肝细胞的水平上介导的，以及在其他表达部位的PAR2损失所致。我们将使用我们的新型肝细胞特异性PAR2-KOPAR2ΔHEP小鼠来定义和验证肝脏PAR2在这些深刻的代谢作用中的特定参与。目前尚不清楚PAR2如何促进饮食诱导的肥胖模型中的胰岛素抵抗。 AIM 2将探索一种新的机制，即PAR2激活GQ-PLC途径，以刺激钙通量和CAMKK2以干扰Akt-葡萄糖信号的胰岛素激活。为了解释我们的初步数据，即全球PAR2缺陷降低了基础血浆葡萄糖，但在瘦肉和肥胖的小鼠模型中增加了肝葡萄糖和糖原，AIM 3将测试肝细胞PAR2抑制主要肝葡萄糖转运蛋白glut2的假设，该假设通过潜在的机械机制通过涉及GQ-MAP-Foxa3的机械机制。 AIMS 1-3将利用我们开发的遍状技术在质膜内表面上靶向G蛋白偶联受体，以帮助描述异常肝脏代谢和胰岛素耐药性的体外和体内胰岛素耐药性中的特定PAR2效果信号通路。