Paracrine Signaling by Kupffer Cells in Hepatic Insulin Resistance

肝胰岛素抵抗中库普弗细胞的旁分泌信号传导

• 批准号: 9029321
• 负责人: MICHAEL P CZECH
• 金额: $ 57.56万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-03-09 至 2019-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9029321
• 关键词: Address; Affect; Animal Model; Attenuated; CD14 Antigen; CD14 gene; CD36 gene; Cell Lineage; Cell Transplantation; Cells; Ceramides; Cytokine Signaling; Data; Diabetes Mellitus; Dissociation; Educational process of instructing; Encapsulated; Endotoxins; Experimental Models; Fatty Acids; Fatty Liver; Fatty acid glycerol esters; Functional disorder; Gene Expression; Gene Silencing; Gene Targeting; Genes; Glucans; Glucose Intolerance; Goals; Health; Hepatic; Hepatocyte; Human; Immune; Immunologic Receptors; Inflammation; Inflammatory; Insulin; Insulin Resistance; Interleukin-1; Interleukin-1 beta; Knockout Mice; Knowledge; Kupffer Cells; Lead; Left; Lipids; Liver; Liver diseases; MAPK8 gene; Mediating; Mediator of activation protein; Metabolic; Metabolic Diseases; Metabolism; Methods; Molecular; Mus; Myeloid Cells; Non-Insulin-Dependent Diabetes Mellitus; Obese Mice; Obesity; Organ; Paracrine Communication; Pathology; Pathway interactions; Peptides; Population; Proteins; Proteomics; Research; Rodent; Role; Signal Transduction; Small Interfering RNA; TLR4 gene; TNF gene; Technology; Testing; Tissues; Transgenic Mice; Triglycerides; cytokine; deep sequencing; design; glucose metabolism; glucose output; glucose tolerance; in vivo; insight; insulin sensitivity; insulin signaling; insulin tolerance; liver inflammation; macrophage; metabolic profile; mouse model; new technology; novel; nutrition; p65; paracrine; receptor; release factor; response; scavenger receptor; sensor; uptake

 DESCRIPTION (provided by applicant): The overall long term goal of this project is to understand the mechanisms that generate fatty liver and hepatic insulin resistance in obesity, and the molecular relationships between these two phenomena. We seek to unravel the paradox whereby hepatic steatosis is tightly correlated with insulin resistance in humans, whereas these pathways can be clearly dissociated in experimental models. We hypothesize that this paradox may be solved by investigating Kupffer cells as mediators of insulin resistance in neighboring hepatocytes through their release of inflammatory cytokines in response to innate immune receptors and lipid sensors CD36 and Msr1 scavenger receptor. New evidence that these lipid sensors activate inflammasome and NFkB pathways in Kupffer cells provides a plausible mechanism whereby over-nutrition in obesity can lead to activation of liver inflammation. In order to attack this problem, we developed a unique glucan encapsulated siRNA (GeRP) delivery method to silence genes selectively in macrophages and Kupffer cells that reside specifically in liver, while leaving hepatocytes and macrophages in other tissues unaffected. With this method we can selectively probe Kupffer cell contributions to hepatocyte function in vivo in various mouse models of obesity. Using this approach we shall selectively silence Kupffer cell NFkB p65, Nlrp3, TLR4 co-receptor CD14, CD36 and Msr1 and other targets, alone and in combinations, to disrupt release of inflammatory factors in vivo. Metabolic profiling will be performed on these mice (glucose tolerance, insulin tolerance, systemic insulin sensitivity, hepatic glucose output and other metabolic parameters) to assess systemic effects of silencing Kupffer cell inflammation. We will then test the hypothesis that Kupffer cell factors that modulate whole body metabolism do so by paracrine signaling to neighboring hepatocytes. We also seek to discover novel Kupffer cell factors that disrupt hepatic insulin sensitivity using deep sequencing, proteomics and lipidomics approaches. Finally, we shall identify which intracellular pathways within hepatocytes cause impaired hepatocyte insulin signaling in response to Kupffer cell factors. Candidates such as DAG, ceramides, JNK as well as novel signaling components found in unbiased screens will be evaluated following GeRP-mediated silencing of inflammatory pathways in Kupffer cells in vivo.

 描述(申请人提供)：本项目的总体长期目标是了解肥胖症患者脂肪肝和肝脏胰岛素抵抗的产生机制，以及这两种现象之间的分子关系。我们试图揭开这样一个悖论，即在人类中，肝脏脂肪变性与胰岛素抵抗密切相关，而这些途径在实验模型中显然是分离的。我们推测，这一悖论可以通过研究Kupffer细胞作为邻近肝细胞胰岛素抵抗的媒介来解决，Kupffer细胞通过其对天然免疫受体和脂质传感器CD36和Msr1清道夫受体的反应释放炎性细胞因子。这些脂质感受器激活Kupffer细胞中的炎症体和NFkB通路的新证据提供了一种可信的机制，即肥胖时的过度营养可能导致肝脏炎症的激活。为了解决这个问题，我们开发了一种独特的葡聚糖包裹的siRNA(GERP)传递方法，可以选择性地沉默驻留在肝脏中的巨噬细胞和Kupffer细胞中的基因，而不影响其他组织中的肝细胞和巨噬细胞。利用这种方法，我们可以选择性地在体内探索Kupffer细胞对各种肥胖小鼠模型肝细胞功能的贡献。使用这种方法，我们将选择性地沉默Kupffer细胞NFkB p65、Nlrp3、TLR4共同受体CD14、CD36和Msr1以及其他靶点，以干扰体内炎症因子的释放。将对这些小鼠进行代谢分析(葡萄糖耐量、胰岛素耐量、全身胰岛素敏感性、肝脏葡萄糖输出量和其他代谢参数)，以评估沉默库普弗细胞炎症的全身影响。然后我们将验证这样的假设，即调节全身新陈代谢的库普弗细胞因子是通过旁分泌信号传递给邻近的肝细胞来实现的。我们还试图利用深度测序、蛋白质组学和脂类组学方法发现新的库普弗细胞因子，这些因素可以破坏肝脏的胰岛素敏感性。最后，我们将确定肝细胞内的哪些细胞内途径导致Kupffer细胞因子反应的肝细胞胰岛素信号受损。候选基因如DAG、神经酰胺、JNK以及在无偏筛选中发现的新的信号成分将在体内GERP介导的库普弗细胞炎症通路沉默后进行评估。