Mechanisms of insulin resistance related to nonalcoholic steatohepatitis

非酒精性脂肪性肝炎相关胰岛素抵抗机制

基本信息

批准号：
10161771
负责人：
MICHAEL P CZECH
金额：
$ 66.91万
依托单位：
UNIV OF MASSACHUSETTS MED SCH WORCESTER
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-03-09 至 2024-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10161771
关键词：
Acetyl Coenzyme A Address Antisense RNA Attenuated Chemicals Cholesterol Clinic Clinical Collagen Data Dependence Diabetes Mellitus Diet Dissociation Down-Regulation Erinaceidae Extravasation Fatty Acids Fatty Liver Fatty acid glycerol esters Fibrosis Functional disorder Gene Combinations Gene Silencing Gene Targeting Genes Genetic Gluconeogenesis Goals Health Hepatic Hepatocyte Human Immune response Inflammation Insulin Resistance Knockout Mice Knowledge Kupffer Cells Lipids Liver Liver Mitochondria Measures Methods Mitochondria Modeling Modification Molecular Mus Non-Insulin-Dependent Diabetes Mellitus Obesity Palmitates Paracrine Communication Pathway interactions Pharmaceutical Preparations Production Pyruvate Carboxylase RNA RNA Interference RNA delivery Research Rodent Steatohepatitis Subcutaneous Injections Syndrome Technology Testing Therapeutic Therapeutic Agents Thinness Time Toxic effect Transgenic Mice Triglycerides Viral Vector base comorbidity cost experimental study glucose tolerance in vivo in vivo evaluation liver inflammation mouse model non-alcoholic non-alcoholic fatty liver disease nonalcoholic steatohepatitis novel novel therapeutic intervention paracrine small molecule stellate cell therapeutic lead compound tool transcription factor uptake

项目摘要

The long term goal of this project is to understand the underlying mechanisms that cause fatty liver (NAFLD) and nonalcoholic steatohepatitis (NASH) in obesity/type 2 diabetes, and how such mechanisms relate to systemic insulin resistance. We also seek to unravel the paradox that while NASH is tightly correlated with insulin resistance in obese humans and mice, these two syndromes are clearly dissociated in certain gene KO mouse models. The central hypothesis of this proposal solves this riddle by positing that hepatocyte cytosolic Acetyl CoA levels promote NAFLD and NASH through producing palmitate/cholesterol toxicity, while hepatocyte mitochondrial Acetyl CoA levels drive insulin resistance by stimulating pyruvate carboxylase and gluconeogenesis. Thus, we propose that while hepatocyte Acetyl CoA pools are often coordinately elevated, they can be disconnected in certain genetic mouse models of obesity and fatty liver. In order to test our hypothesis and attack this problem directly, we apply novel gene silencing technology that combines unique RNA modifications and GalNAC-directed hepatocyte targeting in “self delivery” RNAi (sdRNA) compounds. These compounds can silence single or multiple targeted hepatocyte genes for 2 months or more after a single subcutaneous injection in mice. Using GalNAC-sdRNA, we can selectively target and silence each of the multiple pathways that produce cytosolic Acetyl CoA (e.g., ACLY and ACSS2 pathways) versus mitochondrial Acetyl CoA(e.g., FATP2/5 pathway), while avoiding prohibitive costs and time in generating multiple gene KO mice. In Aim 1, we couple this powerful RNAi technology with a novel method that quantifies hepatocyte mitochondrial Acetyl CoA vs total cellular Acetyl CoA to determine the relative contributions of ACLY, ACSS2 and FATP2, FATP5 to these specific hepatocyte Acetyl CoA pools in lean and HFD mice. In Aim 2 we propose to deplete hepatocyte cytosolic Acetyl CoA in NAFLD/NASH mouse models by appropriate GalNAC-sdRNA gene targeting learned from Aim 1, and determine its impact on liver triglyceride, inflammation, fibrosis and glucose tolerance as well as its impact on Kupffer and Stellate cell dysfunction. For example, we will test whether depletion of hepatocyte Acetyl CoA levels in NASH mouse models attenuates collagen production by Stellate cells through downregulation of hepatocyte transcription factor TAZ, which drives hepatocyte Indian hedgehog (IHH) secretion and Stellate activation. These studies will also resolve the key question whether Kupffer and Stellate cell dysfunction is driven by hepatocyte NAFLD versus independently promoted by circulating factors, or both. Finally, in Aim 3 we will test a potential therapeutic strategy by determining whether GalNAC-sdRNAs targeting multiple hepatocyte genes will simultaneously alleviate all three syndromes of NAFLD, NASH and insulin resistance in obesity/type 2 diabetes. This approach has major clinical advantages since multiple GalNAC-sdRNAs against different genes consist of the same chemical composition and, unlike small molecules, are evaluated for use in the clinic as a single therapeutic agent.

该项目的长期目标是了解肥胖/2型糖尿病中引起脂肪肝（NAFLD）和非酒精性脂肪性肝炎（NASH）的潜在机制，以及与系统性胰岛素抵抗相关的这些机制如何。我们还试图揭示悖论，尽管NASH与肥胖人和小鼠的胰岛素耐药性密切相关，但这两种综合征在某些基因KO小鼠模型中显然是分离的。该提案的中心假设通过应用肝细胞胞质乙酰基COA水平通过产生棕榈酸/胆固醇的毒性来促进NAFLD和NASH，而肝细胞乙酰基乙酰基COA通过刺激性胰蛋白酶氨基酶和胶质酶促进胰岛素的耐药性来促进NAFLD和NASH。因此，我们建议，虽然肝细胞乙酰基COA池通常会协调升高，但在肥胖和脂肪肝的某些遗传小鼠模型中可能会断开它们。为了测试我们的假设并直接攻击此问题，我们应用了新型的基因沉默技术，将独特的RNA修饰和GalNAC定向的肝细胞靶向组合在“自我递送” RNAi（SDRNA）化合物中。这些化合物在小鼠中单次皮下注射后可以将单个或多个靶向肝细胞基因静音2个月或更多。使用Galnac-SDRNA，我们可以选择性地靶向和沉默在产生胞质乙酰基COA（例如ACLY和ACSS2途径）与线粒体乙酰基COA（例如FATP2/5途径）的多种途径，同时避免了禁止的成本和时间产生多个基因KO小鼠。在AIM 1中，我们将这种强大的RNAi技术与一种新颖的方法相结合，该方法量化了肝细胞线粒体乙酰基COA与总细胞乙酰基COA，以确定ACLY，ACSS2和FATP2，FATP5，FATP5，FATP5，FATP5对这些特定肝细胞乙酰乙基COA的相对贡献。在AIM 2中，我们建议通过适当的GalNAC-SDRNA基因从AIM 1中学到的靶向NAFLD/NASH小鼠模型中的肝细胞胞质乙酰COA，并确定其对肝甘油三酸酯，感染，纤维化，纤维化和葡萄糖耐受性的影响，以及其对kupffer和stelllate Cellate Cellate Cellate Cellate Cellate and dySfunction的影响。例如，我们将测试NASH小鼠模型中肝细胞乙酰COA水平的耗竭是否会通过下调肝细胞转录因子TAZ抑制胶原蛋白的产生，从而驱动肝细胞印度Hedgehog（IHH）分泌物和稳定活化。这些研究还将解决库普弗和星状细胞功能障碍是由肝细胞NAFLD驱动的，而不是由循环因子或两者兼而有之。最后，在AIM 3中，我们将通过确定靶向多个肝细胞基因的GALNAC-SDRNA是否会简单地减轻肥胖/2型糖尿病中NAFLD，NASH和胰岛素抵抗的所有三种综合征。这种方法具有主要的临床优势，因为多个GALNAC-SDRNA针对不同的基因由相同的化学组成组成，并且与小分子不同，在诊所中评估了作为单个治疗剂。