Ceramides as Lipotoxic Mediators of Non-Alcoholic Fatty Liver Diseases and Non-Alcoholic Steatohepatitis

神经酰胺作为非酒精性脂肪肝病和非酒精性脂肪性肝炎的脂毒性介质

• 批准号: 10427190
• 负责人: ANNELISE POSS
• 金额: $ 1.25万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10427190
• 关键词: Ablation; Adult; Amino Acids; Apoptosis; Atherosclerosis; Attenuated; Automobile Driving; Ceramidase; Ceramides; Chemicals; Cirrhosis; Complex; Coupled; Data; Development; Diet; Disease; Disease Progression; Enzymes; Evaluation; Experimental Designs; Fatty Acids; Fatty Liver; Fatty acid glycerol esters; Fellowship; Fibrosis; Gangliosides; Genes; Genetic study; Genetically Engineered Mouse; Goals; Health; Hepatic; Hepatocyte; Histologic; Histopathology; Hypertriglyceridemia; In Vitro; Individual; Insulin Resistance; Intervention; Link; Lipids; Liver; Liver Fibrosis; Mass Spectrum Analysis; Mediating; Mediator of activation protein; Membrane; Mentorship; Metabolic; Metabolic syndrome; Metabolism; Mitochondria; Modeling; Molecular; Mus; Non-Rodent Model; Obesity; Outcome; Pathogenesis; Pathology; Patients; Pharmacology; Population; Pre-Clinical Model; Primary carcinoma of the liver cells; Process; Production; Publishing; Research; Rodent; Role; Series; Serum; Sphingolipids; Sphingomyelins; Sphingosine; Statistical Data Interpretation; Steatohepatitis; System; Testing; Therapeutic; Tissues; Training; Vertebral column; Work; base; career; cell type; combat; desaturase; dihydroceramide; dihydroceramide desaturase; effective therapy; endoplasmic reticulum stress; galactosylgalactosylglucosylceramidase; genetic manipulation; glucose metabolism; glucose tolerance; human disease; improved; in vivo; insight; insulin signaling; knockout animal; lifestyle intervention; lipid metabolism; liver injury; mouse model; non-alcoholic fatty liver disease; nonalcoholic steatohepatitis; novel; pi bond; pre-clinical; prevent; research study; skill acquisition; transcriptome sequencing

ABSTRACT Non-alcoholic fatty liver disease (NAFLD) and subsequent progression to non-alcoholic steatohepatitis (NASH) are hepatic manifestations of the metabolic syndrome that represent an unmet therapeutic need. This fellowship application proposes to evaluate the role of a class of lipotoxic fat molecules, termed ceramides, in driving hepatic steatosis and fibrosis. Despite prior studies determining ceramides may be amongst the most deleterious fat-derived metabolites that accumulate in obesity, detailed genetic studies directly manipulating ceramide levels in pre-clinical models of NASH have yet to be performed, lending the research proposed herein novel. Specifically, mechanisms of ceramides within hepatocytes will be probed. Preliminary data demonstrate a single double bond within the sphingosine backbone of these lipids as necessary for these liver pathologies to manifest in mice. Genetically engineered mice lacking dihydroceramide desaturase 1 (DES1), which inserts this double bond, show blunted ceramide levels with a concomitant increase in the dihydroceramides lacking the unique structural feature. When evaluated in preclinical NASH and fibrosis models, whole body DES1 knockout animals are protected from hepatic injury. In Aim 1 hepatocyte specific DES1 knockout animals will be evaluated in models of NASH. In Aim 2, ceramides will be elevated through genetic manipulation of acid ceramidase (ASAH1), an enzyme that degrades ceramides. Whole body and hepatocyte specific depletion of ASAH1 will be evaluated on the basis of ceramide accumulation and NASH progression. Based upon RNA sequencing data indicating a close relationship between ceramide concentrations, fibrosis and endoplasmic reticulum (ER) stress, Aim 3 will evaluate the role of ceramide- coupled ER stress in NASH both in vivo and in vitro. This series of gain and loss of ceramide studies will provide insight into the therapeutic potential of ceramide-lowering interventions and mechanistic insight into how ceramides participate in NASH related metabolic perturbation and histopathology. The proposed research will also greatly enrich my graduate training through acquisition of skills detailed in the Sponsor/Co-Sponsor statement (i.e., histological evaluation of NASH, mass spectrometry-based analysis of ceramide levels, mentorship-guided training in experimental design and statistical analysis). The combination of the proposed research studies and the guidance of my Sponsor and Co-Sponsor will yield valuable information regarding NASH disease progression, novel insight into ceramide mechanisms of action, and be a critical step in the development of my independent research career.

摘要 非酒精性脂肪性肝病（NAFLD）和随后进展为非酒精性脂肪性肝炎（NASH） 是代谢综合征的肝脏表现，代表了未满足的治疗需求。这 一项奖学金申请建议评估一类脂毒性脂肪分子（称为神经酰胺）在 导致肝脂肪变性和纤维化尽管先前的研究确定神经酰胺可能是最 有害的脂肪衍生代谢产物，积累在肥胖症，详细的遗传研究直接操纵 NASH临床前模型中的神经酰胺水平尚未进行， 在此是新颖的。具体而言，神经酰胺在肝细胞内的机制将被探测。初步数据 证明了这些脂质的鞘氨醇骨架内的单个双键对于这些肝脏是必需的 在小鼠中表现出的病理学。缺乏二氢神经酰胺去饱和酶1（DES 1）的基因工程小鼠， 插入这个双键，表现出钝化的神经酰胺水平，伴随着神经酰胺水平的增加。 二氢神经酰胺缺乏独特的结构特征。在临床前NASH和纤维化中进行评价时 模型中，全身DES 1敲除动物免受肝脏损伤。In Aim 1肝细胞特异性 将在NASH模型中评价DES 1敲除动物。在目标2中，神经酰胺将通过 酸性神经酰胺酶（ASAH 1）的遗传操作，这是一种降解神经酰胺的酶。全身和 将根据神经酰胺蓄积和NASH评价肝细胞特异性ASAH 1耗竭 进展基于RNA测序数据，表明神经酰胺与 浓度，纤维化和内质网（ER）应激，目的3将评估神经酰胺的作用， 在体内和体外NASH中偶联ER应激。这一系列的神经酰胺的获得和损失的研究将 深入了解降低神经酰胺干预的治疗潜力，并深入了解 神经酰胺如何参与NASH相关的代谢紊乱和组织病理学。拟议研究 我还将通过获得赞助商/共同赞助商中详细介绍的技能，极大地丰富我的研究生培训 语句（即，NASH的组织学评价、基于质谱的神经酰胺水平分析 实验设计和统计分析的指导培训）。建议的组合 研究以及我的申办者和共同申办者的指导将产生有关以下方面的有价值信息 NASH疾病进展，对神经酰胺作用机制的新见解，并成为治疗NASH疾病进展的关键步骤。 我的独立研究生涯。