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: 10314863
• 负责人: ANNELISE POSS
• 金额: $ 3.6万
• 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 2023-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10314863
• 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; Structure; 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.

抽象的 非酒精性脂肪肝病（NAFLD），随后发展为非酒精性脂肪性肝炎（NASH） 代表未满足的治疗需求的代谢综合征的肝表现。这 奖学金应用建议评估一类脂毒性脂肪分子的作用，称为神经酰胺，在 驱动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大的 在肥胖，详细的遗传研究中积累的有害脂肪衍生的代谢产物直接操纵 NASH前临床模型中的神经酰胺水平尚未进行，借出了建议的研究 此小说。具体而言，将探测肝细胞内神经酰胺的机制。初步数据 必要 在小鼠中表现出的病理。缺乏二氢氧酰胺去饱和酶1（DES1）的基因工程小鼠， 插入这种双键，显示出钝的神经酰胺水平，并随之增加 缺乏独特的结构特征的二氢可胺。在临床前纳什和纤维化中评估时 模型，全身DES1敲除动物受到肝损伤的保护。在AIM 1中特定于肝细胞 DES1基因敲除动物将在NASH模型中评估。在AIM 2中，神经酰胺将通过 酸神经酶（ASAH1）的遗传操纵，一种降解神经酰胺的酶。全身和 将根据神经酰胺的积累和NASH评估ASAH1的肝细胞特异性耗竭 进展。基于RNA测序数据，表明神经酰胺之间存在密切的关系 浓度，纤维化和内质网（ER）应力，AIM 3将评估神经酰胺的作用 在体内和体外，nash中的ER应力耦合。这一系列的神经酰胺研究的收益和丧失将 洞悉降低神经酰胺的干预措施的治疗潜力以及对机械性的洞察力 神经酰胺如何参与NASH相关的代谢扰动和组织病理学。拟议的研究 还将通过获取赞助商/共同赞助商中详细介绍的技能来大力丰富我的研究生培训 陈述（即，基于质谱法的组织学评估，基于质谱的神经酰胺水平的分析， 实验设计和统计分析中的指导指导培训）。提议的组合 研究研究以及我的赞助商和共同发起人的指导将产生有关的宝贵信息 纳什疾病的进展，对神经酰胺作用机制的新洞察力，并成为关键的一步 我的独立研究生涯的发展。