Mechanisms of HIF1 alpha mediated dysregulated skeletal muscle proteostasis in alcoholic liver disease

HIF1α介导的酒精性肝病骨骼肌蛋白稳态失调的机制

• 批准号: 10579341
• 负责人: Nicole Welch
• 金额: $ 17.91万
• 依托单位: CLEVELAND CLINIC LERNER COM-CWRU
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-03-01 至 2026-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10579341
• 关键词: Address; Adverse effects; Alcohol consumption; Alcoholic Liver Cirrhosis; Alcoholic Liver Diseases; Alcohols; Ammonia; Autophagocytosis; Award; Biological Assay; Biopsy Specimen; Career Choice; Chromatin; Chronic Disease; Cirrhosis; Citric Acid Cycle; Clinical; Collaborations; Complex; Data; Degradation Pathway; Development; Environment; Ethanol; Exposure to; FRAP1 gene; Fellowship; Foundations; Funding; Genetic Transcription; Goals; HIF1A gene; Heart failure; Hepatic; Human; Hyperammonemia; Hypoxia; Hypoxia Inducible Factor; Impairment; In Vitro; Institution; Kidney Failure; Label; Link; Liver diseases; Mediating; Mentors; Metabolic; Molecular; Molecular Target; Morbidity - disease rate; Mus; Muscle; Muscle Fibers; Muscle Proteins; Muscular Atrophy; National Institute on Alcohol Abuse and Alcoholism; Ohio; Outcome; Oxygen; Patients; Phenotype; Phosphotransferases; Physicians; Physiological; Pilot Projects; Post-Translational Protein Processing; Pre-Clinical Model; Prevalence; Protein Biosynthesis; Reporter; Reporting; Research; Research Methodology; Research Personnel; Research Project Grants; Scientist; Signal Transduction; Signaling Molecule; Skeletal Muscle; Stress; Testing; Time; Tissues; Training; Translational Research; Transposase; United States; Validation; Work; alcohol consequences; alcohol exposure; alcohol response; alcohol testing; alcohol use disorder; alpha ketoglutarate; biobank; career development; clinical training; clinical translation; clinically significant; effective therapy; experimental study; gain of function; hepatic ureagenesis; in vivo; inhibitor; liver transplantation; loss of function; lung failure; metabolic abnormality assessment; mitochondrial dysfunction; mortality; muscle form; muscle strength; novel; preservation; programs; proteostasis; response; sarcopenia; skeletal muscle wasting; targeted treatment; therapeutically effective; tissue injury; transcription factor; uptake

The prevalence of alcohol use disorders and consequent tissue injury, primarily alcoholic liver disease (ALD) continue to increase. Skeletal muscle loss or sarcopenia is a consistent abnormality in patients with ALD and is associated with adverse clinical outcomes that include increased mortality, other complications of liver disease and poor post-liver transplant outcomes. We have recently reported more severe muscle loss and a greater rate of muscle loss in patients with alcoholic cirrhosis compared with those in other causes of cirrhosis. Despite the high clinical significance of sarcopenia in ALD there are no effective therapeutic options because the underlying mechanisms are not well understood. We also reported that ethanol, directly and indirectly via impaired hepatic ammonia disposal and consequent hyperammonemia, results in a sarcopenic phenotype with dysregulated protein homeostasis (proteostasis). In preliminary studies, we have shown mitochondrial dysfunction in response to ethanol and hyperammonemia. We also noted that ethanol results in cataplerosis or loss of tricarboxylic acid (TCA) cycle intermediates, specifically α-ketoglutarate (αKG) an inhibitor of HIF1α. Consistently, unbiased approaches (assay for transposase accessible chromatin sequencing), and targeted experiments showed oxygen independent stabilization of muscle hypoxia inducible factor-1α (HIF1α) with ammonia. In pilot studies, we observed an increased expression of REDD1, a transcriptional target of HIF1α and a negative regulator of the mammalian target of rapamycin complex 1 (mTORC1) that maintains skeletal muscle proteostasis with functional responses. We also noted relative preservation of muscle mass during hyperammonemia in muscle specific deletion of HIF1α mice. These observations formed the basis for our hypothesis that ethanol induced hyperammonemia causes cataplerosis of αKG with oxygen independent stabilization and impaired proteostasis and sarcopenia. We will test this hypothesis by testing if ethanol stabilizes HIF1α in skeletal muscle, and determine the mechanisms of stabilization of muscle HIF1α. Ethanol treatment in vitro in myotubes and in vivo in mice with loss and gain of function of HIF1α and its regulatory molecules will be used for these studies We will also test how metabolic perturbations regulate HIF1α stabilization and consequent molecular and functional responses in our preclinical models. Validation of key observations will be done in human muscle tissue from our biorepository. The proposed studies will enhance our understanding of the mechanisms of sarcopenia in ALD and lay the foundation for targeted therapeutics. This award will provide the support and time for the applicant for a supervised research career development in translational research. The applicant works with NIAAA funded independent investigators in the Northern Ohio Alcohol Center and her mentor developed the field of sarcopenia in liver disease. The institutional environment is highly supportive of her career path towards becoming an independent physician scientist focusing on mechanistic approaches to address unmet clinical needs in patients with alcohol use disorders.

酒精使用障碍和随之而来的组织损伤的患病率，主要是酒精性肝病（ALD） 继续增加。骨骼肌丧失或肌肉减少症是 ALD 患者的一贯异常现象，并且 与不良临床结果相关，包括死亡率增加、肝病的其他并发症 以及肝移植术后效果不佳。我们最近报告了更严重的肌肉损失和更大的 与其他原因引起的肝硬化患者相比，酒精性肝硬化患者的肌肉损失率。尽管 ALD 中肌肉减少症的高度临床意义目前尚无有效的治疗选择，因为 根本机制尚不清楚。我们还通过直接和间接报道乙醇 肝氨处理受损和随之而来的高氨血症，导致肌少症表型 蛋白质稳态失调（蛋白质稳态）。在初步研究中，我们已经表明线粒体 对乙醇和高氨血症的反应功能障碍。我们还注意到乙醇会导致猝倒症或 三羧酸 (TCA) 循环中间体的损失，特别是 α-酮戊二酸 (αKG)（HIF1α 的抑制剂）。 始终如一的、公正的方法（转座酶可及染色质测序的测定）和有针对性的 实验表明肌肉缺氧诱导因子 1α (HIF1α) 的氧依赖性稳定 氨。在试点研究中，我们观察到 REDD1（HIF1α 的转录靶标）的表达增加 以及维持骨骼健康的哺乳动物雷帕霉素靶标复合物 1 (mTORC1) 的负调节因子 肌肉蛋白质稳态与功能反应。我们还注意到肌肉质量的相对保存 HIF1α 肌肉特异性缺失小鼠的高氨血症。这些观察结果构成了我们的基础 假设乙醇诱导的高氨血症导致 αKG 不依赖氧的猝倒症 稳定性和蛋白质稳态受损以及肌肉减少症。我们将通过测试乙醇是否 稳定骨骼肌中的 HIF1α，并确定肌肉 HIF1α 的稳定机制。乙醇 HIF1α 功能丧失和获得及其调节的体外肌管治疗和小鼠体内治疗 分子将用于这些研究我们还将测试代谢扰动如何调节 HIF1α 我们的临床前模型中的稳定性以及随后的分子和功能反应。验证密钥 观察将在我们的生物样本库的人体肌肉组织中进行。拟议的研究将增强 我们对 ALD 中肌肉减少症机制的理解为靶向治疗奠定了基础。 该奖项将为申请人在监督下的研究职业发展提供支持和时间 转化研究。申请人与 NIAAA 资助的俄亥俄州北部的独立调查员合作 酒精中心和她的导师开发了肝脏疾病中的肌肉减少症领域。制度环境 高度支持她成为一名独立医师科学家的职业道路，专注于 解决酒精使用障碍患者未满足的临床需求的机械方法。