Bilirubin Catabolism induces Plasminogen-Activator Inhibitor 1 (PAI-1) worsening Metabolic Dysfunction

胆红素分解代谢诱导纤溶酶原激活剂抑制剂 1 (PAI-1) 恶化代谢功能障碍

• 批准号: 10750132
• 负责人: Zachary A Kipp
• 金额: $ 3.37万
• 依托单位: UNIVERSITY OF KENTUCKY
• 依托单位国家: 美国
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-01-01 至 2026-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10750132
• 关键词: Adipose tissue; Affect; Antioxidants; Arterial Fatty Streak; Bilirubin; Binding; Blood Pressure; Blood Vessels; Body Weight; Calories; Cardiovascular Diseases; Cardiovascular system; Catabolism; Cause of Death; Cessation of life; Cholesterol; Circulation; Coagulation Process; Data; Development; Diet; Environment; Enzymes; Excretory function; Fat-Restricted Diet; Fatty acid glycerol esters; Fellowship; Fibrosis; Financial Hardship; Foundations; Future; Generations; Genetic Polymorphism; Gilbert Disease; Glucuronic Acids; Goals; Healthcare Systems; Heart; Heart Diseases; Heart failure; Heme; Hepatic; High Fat Diet; Hormonal; Human; Intestines; Knock-out; Knockout Mice; Lead; Link; Liver; Measures; Mediator; Messenger RNA; Metabolic; Metabolic Diseases; Metabolic dysfunction; Mus; Nuclear Receptors; Obese Mice; Obesity; PPAR alpha; Pathway interactions; Patients; Physiological; Plasma; Plasminogen Activator Inhibitor 1; Portal System; Prevention; Production; Proteins; RNA Interference; Research; Research Proposals; Research Technics; Risk; Risk Factors; Role; Scientist; Serum; Structure; Technology; Testing; Therapeutic; Thinness; Training; Translating; Travel; UGT1A1 gene; United States; Water; Woman; Work; absorption; bile duct; cardioprotection; cardiovascular disorder prevention; cardiovascular disorder risk; career; comorbidity; diet-induced obesity; feeding; glucose tolerance; gut microbiota; improved; men; mouse development; new therapeutic target; novel marker; novel therapeutics; obese patients; prevent; promoter; therapeutic target; tool; transcriptome; transcriptome sequencing

Summary: Urobilin is formed in the intestine as a biproduct of conjugated bilirubin catabolism. Currently, the physiological function of urobilin is unknown. Human association studies have indicated a positive correlation to obesity and cardiovascular diseases (CVD). Since obesity is a major risk factor for the development of CVD, we hypothesized that urobilin levels might change with the altered metabolic state and induce adiposity. To determine the role of urobilin in lean mice, we treated C57/bl6 mice on a normal-chow diet with urobilin for 4 weeks. We found that urobilin had no effect on body weight but significantly increased adiposity in the inguinal white adipose tissue (iWAT) depot compared to the vehicle-treated mice. To determine how urobilin changes the transcriptome profile in the iWAT, we preformed RNA-sequencing which showed that urobilin increases the expression of Serpine1 mRNA. Serpine1 is translated into the protein plasminogen activator inhibitor-1 (PAI-1). PAI-1 is secreted into circulation, promoting a prothrombotic environment, and is thought to increase the risk of CVD. The goal of this research proposal is to determine whether urobilin induces CVD via PAI-1 and if this mechanism is a link between CVD and obesity. We will investigate if lowering plasma urobilin is a possible therapeutic for the treatment and prevention of CVD. To study this, in Aim 1, we will use PAI-1 knockout (KO) mice and littermate controls treated with urobilin or vehicle while on a high-fat or calorie-match low-fat diets. We expect the PAI-1KO mice will be protected from urobilin induced CVD. In Aim 2, we will use diet-induced obese (DIO) mice treated with a liver- specific GalNac-Ugt1a1-RNAi or GalNac-scramble control to suppress hepatic Ugt1a1, which is responsible for initiating the conjugation of bilirubin that leads to elevated urobilin production. We show preliminary data that the RNAi technology suppresses Ugt1a1 94.7% and that this leads to a significant (p<0.01) decrease in plasma urobilin and an increase in plasma unconjugated bilirubin. We expect that the suppression of Ugt1a1 will protect the mice from the development of CVD by lowering urobilin levels, increasing unconjugated bilirubin, preventing adiposity and high PAI-1 plasma levels. This is the first proposed mechanism of urobilin in promoting the development of CVD, which we will extensively study to better understand how to reverse its deleterious effects. This fellowship will provided critical training in research techniques, scientific training and professional development to give me the tools to become a successful independent scientist.

概括： 尿胆素在肠道中形成，是结合胆红素分解代谢的副产物。目前，生理 尿胆素的功能尚不清楚。人类关联研究表明，肥胖与肥胖呈正相关。 心血管疾病（CVD）。由于肥胖是 CVD 发展的主要危险因素，我们假设 尿胆素水平可能会随着代谢状态的改变而变化并诱发肥胖。确定角色 在瘦小鼠中使用尿胆素，我们用正常饮食的 C57/bl6 小鼠用尿胆素治疗 4 周。我们发现 尿胆素对体重没有影响，但显着增加腹股沟白色脂肪组织的脂肪含量 (iWAT) 仓库与媒介物处理的小鼠进行比较。确定尿胆素如何改变转录组谱 在 iWAT 中，我们进行了 RNA 测序，结果表明 urobilin 增加了 Serpine1 的表达 mRNA。 Serpine1 被翻译为蛋白纤溶酶原激活剂抑制剂-1 (PAI-1)。 PAI-1 分泌到 循环，促进血栓形成环境，并被认为会增加心血管疾病的风险。此举的目标 研究计划是确定尿胆素是否通过 PAI-1 诱导 CVD，以及该机制是否是两者之间的联系 心血管疾病和肥胖。我们将研究降低血浆尿胆素是否是一种可能的治疗方法，并且 预防心血管疾病。为了研究这一点，在目标 1 中，我们将使用 PAI-1 敲除 (KO) 小鼠和接受治疗的同窝对照小鼠 在高脂肪或热量匹配的低脂肪饮食中使用尿胆素或媒介物。我们预计 PAI-1KO 小鼠将 免受尿胆素诱导的 CVD 的影响。在目标 2 中，我们将使用经过肝脏治疗的饮食诱导肥胖 (DIO) 小鼠。 特异性 GalNac-Ugt1a1-RNAi 或 GalNac-scramble 控制抑制肝 Ugt1a1，其负责 启动胆红素结合，导致尿胆素产量增加。我们显示初步数据表明 RNAi 技术可抑制 Ugt1a1 94.7%，这会导致血浆浓度显着降低 (p<0.01) 尿胆素和血浆非结合胆红素增加。我们预计 Ugt1a1 的抑制将保护 通过降低尿胆素水平、增加未结合胆红素、预防 肥胖和高 PAI-1 血浆水平。这是首次提出尿胆素促进 CVD 的发展，我们将对其进行广泛研究，以更好地了解如何扭转其有害影响。 该奖学金将提供研究技术、科学培训和专业方面的关键培训 发展为我提供了成为一名成功的独立科学家的工具。