Innate Immune Response and Intestinal Inflammation

描述（由申请人提供）： 肝纤维化，细胞外基质蛋白的积累，发生在大多数类型的慢性肝病。肝纤维化患者可能进展为肝硬化，随后出现门静脉高压、肝衰竭和肝细胞癌。不幸的是，对于慢性肝病患者没有有效的抗纤维化治疗。肝星状细胞（hepatic stellate cells，HSC）的活化是肝纤维化发生的中心环节。活化的HSC是纤维化肝脏中主要的细胞外基质蛋白产生细胞类型，并且已经鉴定了关键的纤维化信号，包括通过Toll样受体4（TLR 4）的信号传导。在HSC的活化过程中诱导TLR 4信号传导所需的所有分子，使活化的HSC响应于TLR 4配体如脂多糖（LPS），活化包括NF κ B和JNK的信号传导途径，并合成促炎分子。TLR 4突变小鼠对实验性肝纤维化具有抗性。该项目的目标是进一步确定TLR 4导致肝纤维化的机制，并通过配体结合可溶性受体测试TLR 4作为治疗的潜在靶点。作为本提案基础的基本假设如下：1。细胞内TLR 4接头蛋白和效应分子对LPS刺激后促炎基因表达的贡献不同。2.包括高迁移率族蛋白1（HMGB 1）在内的其他内源性配体直接与TLR 4相互作用并在HSC中诱导促炎作用。3.促炎和纤维化作用可以通过使用调节TLR 4信号传导的可溶性TLR 4受体来阻断。因此，我们希望实现四个具体目标。我们希望进一步确定TLR 4在HSC中介导其作用的信号通路和机制（目的1）。我们将研究HMGB 1作为内源性TLR 4配体对培养的HSC和小鼠肝纤维化模型的影响（目的2）。我们还想确定是否有其他内源性TLR 4配体介导肝纤维化（目的3）。如我们的初步数据所示，我们开发了可溶性TLR 4受体，其抑制HSC中LPS诱导的信号传导和促炎作用。因此，我们希望扩展这些研究，并使用可溶性TLR 4受体作为肝纤维化动物模型的预防和治疗方法（目的4）。总体目标是获得对HSC病理生理学的新见解，并更好地了解慢性肝病的分子机制。最终，这种方法可能会为慢性肝病患者带来一种新的治疗方法。为了实现拟议的研究目标，我将获得额外的专业知识，在复杂的分子生物学技术。在获奖期间，我将继续基础研究，研究肝纤维化，重点是“转化医学”-采取最新的研究成果，并将其转化为临床治疗。

DESCRIPTION (provided by applicant): Liver fibrosis, the accumulation of extracellular matrix proteins, occurs in most types of chronic liver disease. Patients with liver fibrosis may progress to cirrhosis with subsequent portal hypertension, hepatic failure and hepatocellular carcinoma. Unfortunately, there are no effective antifibrotic treatments for patients with chronic liver disease. Activation of hepatic stellate cells (HSCs) is the central event in liver fibrogenesis. Activated HSCs are the main extracellular matrix protein producing cell type in fibrotic liver and key fibrogenic signals have been identified including signaling through toll-like receptor 4 (TLR4). All molecules required for TLR4 signaling are induced during the activation process of HSCs, rendering activated HSCs responsive to TLR4 ligands such as lipopolysaccharide (LPS) with activation of signaling pathways including NFicB and JNK, and the synthesis of pro-inflammatory molecules. TLR4 mutant mice are resistant to experimental liver fibrosis. The goal of this project is to further define the mechanisms by which TLR4 leads to liver fibrosis and to test TLR4 as a potential target of therapy via ligand-binding soluble receptors. The underlying hypotheses that serve as the basis for this proposal are the following: 1. Intracellular TLR4 adaptor proteins and effector molecules contribute differently to pro-inflammatory gene expression following LPS stimulation. 2. Other endogenous ligands including high-mobility group box 1 (HMGB1) directly interact with TLR4 and induce pro-inflammatory effects in HSCs. 3. Pro-inflammatory and fibrogenic actions can be blocked by using a soluble TLR4 receptor that modulates TLR4 signaling. We therefore wish to pursue four specific aims. We want to further define the signaling pathways and mechanisms by which TLR4 mediates its effects in HSCs (aim 1). We will investigate the effect of HMGB1 as endogenous TLR4 ligand on cultured HSCs, and in a mouse model of liver fibrosis (aim 2). We also want to determine whether other endogenous TLR4 ligands mediate hepatic fibrogenesis (aim 3). As shown in our preliminary data, we developed a soluble TLR4 receptor, which inhibits LPS induced signaling and pro-inflammatory actions in HSCs. We therefore want to extend these studies and use the soluble TLR4 receptor as preventive and therapeutic approach in animal models of liver fibrosis (aim 4). The overall goal is to gain new insights into the pathophysiology of HSCs and to provide a better understanding of the molecular mechanisms underlying chronic liver diseases. Eventually this approach might lead to a novel therapy for patients with chronic liver disease. To achieve the proposed research aims, I will gain additional expertise in sophisticated molecular biology techniques. During the time of the award I will continue basic research to study liver fibrosis with an emphasis on "translational medicine" - taking the latest research and translating it into clinical therapies.