Synergy of lipolysis and lipophagy in alcoholic liver disease

脂肪分解和脂肪吞噬在酒精性肝病中的协同作用

• 批准号: 10686384
• 负责人: Micah Schott
• 金额: $ 24.9万
• 依托单位: UNIVERSITY OF NEBRASKA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-20 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10686384
• 关键词: Acid Lipase; Address; Adipocytes; Adipose tissue; Adrenergic Agents; Advisory Committees; Affect; Alcohol consumption; Alcoholic Fatty Liver; Alcoholic Liver Diseases; Alcoholic beverage heavy drinker; Alcohols; Animal Model; Autophagocytosis; Autophagosome; Biochemistry; Bioinformatics; Biological; Biology; Catabolism; Cells; Cholesterol; Cirrhosis; Clinic; Committee Members; Complement; Complex; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Cytoplasm; Data; Development; Disease Progression; Elderly; Endosomes; Environment; Enzymes; Event; Fatty Liver; Fibrosis; Future; Gastroenterology; Genetic Transcription; Goals; Hepatic; Hepatitis; Hepatocyte; Hepatology; Hydrolysis; Impairment; Knowledge; Lipase; Lipids; Lipolysis; Liver; Lysosomes; Malignant Neoplasms; Manuscripts; Mass Spectrum Analysis; Mediating; Membrane; Mentors; Microscopy; Multivesicular Body; Obesity; Organelles; Outcome; Pathway interactions; Peripheral; Pharmacotherapy; Phase; Phosphotransferases; Positioning Attribute; Postdoctoral Fellow; Process; Progressive Disease; Protein Kinase; Protein phosphatase; Proteins; Proteome; Proteomics; Publishing; Regulation; Research; Rodent Model; Role; Signal Transduction; Sorting; Surface; Testing; Training; Triglycerides; Vesicle; Work; cell type; chronic alcohol ingestion; combat; comparative; graduate school; in vivo; insight; late endosome; liver injury; multidisciplinary; novel; pharmacologic; problem drinker; protein activation; public health relevance; receptor; recruit; response; skills; sterol esterase; synergism; trafficking; transcription factor; uptake

Project Summary/Abstract My long-term objective is to discover new cellular mechanisms that contribute to alcoholic liver disease (ALD), a progressive disease leading to non-reversible stages that can be fatal. One of the early and reversible precursors of ALD is alcoholic steatosis, in which large triglyceride and cholesterol-rich lipid droplets (LDs) accumulate within hepatocytes, the main functional cell type of the liver. While LDs are believed to be central to the progression of ALD, the cellular mechanisms whereby alcohol disrupts the breakdown of these organelles are poorly understood. To address this important gap in knowledge, this proposal will define the synergy between two seemingly-distinct processes of lipid droplet catabolism: lipolysis, which utilizes the cAMP pathway to activate and recruit cytosolic lipases to the LD surface, and lipophagy, which utilizes membrane trafficking events that lead to LD breakdown by lysosomal lipases. Preliminary data suggest that lipolysis and lipophagy machinery target discrete, size-based LD subpopulations, and that small LDs are targeted for direct engulfment by multivesicular bodies (MVBs) for catabolism through the late endosomal pathway. Thus, the central hypothesis of this proposal is that EtOH disrupts a sequential mechanism whereby lipolysis acts on large LDs to reduce their size for direct uptake by endosomal microlipophagy. In Aim 1, I will determine the role of cytosolic lipases in protecting against ALD progression. In Aim 2, I will determine effect of EtOH on a sequential “lipolysis-to-lipophagy” pathway and define the mechanisms by which MVB/endosomes facilitate microlipophagy of small LDs. In Aim 3, I will integrate my previous expertise with this new knowledge and training to define novel cAMP signaling mechanisms that support lipolysis and lipophagy to combat alcoholic steatosis. The exceptionally strong research environment within Mayo Clinic’s Division of Gastroenterology and Hepatology is ideal for this training. To accomplish these aims, I will receive hands-on training in rodent models of chronic alcohol consumption, comparative proteomics, and bioinformatics. This new training complements my current skillset in cell signaling, microscopy, and biochemistry, and provides a multidisciplinary toolbox to comprehensively assess lipid catabolism in the liver. The proposed research will integrate my expertise in cAMP/PKA signaling mechanisms from my graduate school training with my postdoctoral expertise in lipid droplet biology and alcoholic steatosis. With the help of my mentor, Dr. Mark McNiven, along with a strong research team including two collaborators and four advisory committee members, I will have all the expertise and training needed to successfully accomplish these aims and transition to an independent research position. The results gained from the proposed research will provide a mechanistic understanding of lipid droplet catabolism in alcoholic fatty liver. Importantly, these studies will provide published research manuscripts and preliminary data in support of a future R01 proposal.

项目总结/摘要 我的长期目标是发现导致酒精肝的新的细胞机制 疾病（ALD），一种导致可能致命的不可逆阶段的进行性疾病。之一 ALD的早期和可逆的前体是酒精性脂肪变性，其中大量的甘油三酯和 富含胆固醇的脂滴（LD）在肝细胞（主要功能细胞类型）内积聚 肝脏的虽然LD被认为是ALD进展的中心，但细胞凋亡是ALD的主要原因。 酒精破坏这些细胞器分解的机制很差， 明白为了填补这一重要的知识空白，本提案将界定协同作用， 在两个截然不同的脂滴分解过程之间：脂解，它利用 cAMP途径激活并将胞质脂肪酶募集到LD表面， 利用膜运输事件导致LD被溶酶体脂肪酶分解。 初步数据表明，脂解和脂肪吞噬机制的目标离散，大小为基础的LD 亚群，并且较小的LD被多泡体直接吞噬 （MVB）通过晚期内体途径用于catalysts。因此，这个问题的核心假设 建议EtOH破坏了脂解作用于大LD的顺序机制， 减小它们的大小以便通过内体微脂吞噬直接摄取。在目标1中，我将确定 胞质脂肪酶在防止ALD进展中的作用。在目标2中，我将确定 EtOH对连续的“脂解-至-脂肪吞噬”途径的影响，并定义了 MVB/内体促进小LD的微噬脂作用。在目标3中，我将整合我以前的 这些新知识和培训的专业知识，以定义新的cAMP信号传导机制， 支持脂肪分解和脂肪吞噬以对抗酒精性脂肪变性。异常强大的研究 马约医院消化内科和肝病科的环境是理想的 训练为了实现这些目标，我将接受啮齿动物慢性炎症模型的实践培训。 酒精消费，比较蛋白质组学和生物信息学。This new training 补充了我目前在细胞信号传导，显微镜和生物化学方面的技能，并提供了一个 多学科工具箱，以全面评估肝脏中的脂质代谢。拟议 研究将整合我的专业知识在cAMP/PKA信号机制，从我的毕业 我在学校的培训和博士后的专业知识，在脂滴生物学和酒精性脂肪变性。 在我的导师Mark McNiven博士的帮助下，沿着有一个强大的研究团队， 合作者和四个咨询委员会成员，我将拥有所有的专业知识和培训 需要成功地实现这些目标，并过渡到独立的研究 位置从拟议的研究中获得的结果将提供一个机制 对酒精性脂肪肝脂滴催化剂的认识重要的是，这些研究 提供已发表的研究手稿和初步数据，以支持未来的R 01 提议