G Protein pathways as Novel Therapeutic and Diagnostic Targets in Liver Fibrosis

G 蛋白通路作为肝纤维化的新治疗和诊断靶点

基本信息

批准号：
8689692
负责人：
Pradipta Ghosh
金额：
$ 23.25万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN DIEGO
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-07-01 至 2017-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8689692
关键词：
Acute Animals Apoptosis Autoimmune Diseases CCL2 gene Cell physiology Cells Chemotaxis Chronic Chronic Hepatitis C Chronic viral hepatitis Cirrhosis Clinical Code Collagen Complex Coupled Cyclic AMP Deltastab Deposition Development Equilibrium Extracellular Matrix Extracellular Matrix Proteins Family Fibrosis Future GTP-Binding Proteins Glial Fibrillary Acidic Protein Goals Growth Factor Growth Factor Receptors Healthcare Heavy Drinking Hepatic Stellate Cell Hepatitis C Human Immunoblotting Immunohistochemistry Inflammation Inflammatory Injection of therapeutic agent Injury Intercept Kupffer Cells Learning Length Ligation Liver Liver Cirrhosis Liver Fibrosis Macrophage Inflammatory Protein-1 Measures Medicine Messenger RNA Modeling Molecular Molecular Target Mus Myofibroblast PDGFRB gene PI3K/AKT Paraffin Embedding Pathway interactions Patients Pattern Pharmaceutical Preparations Phosphorylation Platelet-Derived Growth Factor Play Post-Translational Protein Processing Production Prognostic Marker Property Protein Binding Protein Subunits Proteins RANTES Receptor Protein-Tyrosine Kinases Reverse Transcriptase Polymerase Chain Reaction Risk Role Sampling Signal Pathway Signal Transduction Signaling Molecule Site Staging Stimulus TNF gene Testing Therapeutic Time Tissues Transgenic Mice Viral hepatitis base beta-Chemokines bile duct care burden cell growth cell type chemokine cohort cytokine fibrogenesis forkhead protein human subject immunocytochemistry inhibitor/antagonist insight liver biopsy liver injury macrophage nonalcoholic steatohepatitis novel novel diagnostics novel therapeutics programs promoter public health relevance receptor research study response small molecule stellate cell therapeutic target

项目摘要

DESCRIPTION (provided by applicant): Liver fibrosis caused by excessive alcohol consumption, viral hepatitis, autoimmune diseases and non-alcoholic steatohepatitis (NASH) can progress to cirrhosis and its multiple complications, and represents a massive health care burden worldwide. It is characterized by aberrant signaling by growth factor receptor tyrosine kinases (RTKs) and Gi-coupled chemokine/cytokine family of GPCRs, e.g., the CCRs), incited by chronic injury/inflammation, causing excessive deposition of extracellular matrix, mainly produced by activated hepatic stellate cells (HSCs). In response to fibrogenic stimuli, quiescent HSCs transform into a collagen- producing myofibroblast-like cell. A key profibrotic trigger for this critical transformation is the PI3K-Akt pathway, whereas a key antifibrotic stimulus is cAMP. The PI3K-Akt pathway is also critical for chemotaxis of KCs, which play another set of critical role in liver fibrosis. The precise mechanism(s) that coordinately drives unrestricted PI3K-Akt signaling and simultaneously reduces cAMP downstream of these diverse classes of receptors culminating into liver fibrosis remains unknown. Recently a novel signaling complex comprised of G protein subunit, G?i and GIV, its non-receptor GEF has been identified, which inhibits cAMP production, and enhances PI3K-Akt signals initiated by both growth factor receptor receptors and GPCRs. It is hypothesized that these signaling programs driven by the GIV-Gi signaling axis activates HSCs and KCs and drives liver fibrosis, and that inhibiting this axis may halt and reverse fibrosis. To test this hypothesis, the expression, posttranslational modifications and G-protein binding properties of GIV will be investigated during the course of acute and chronic liver injury in murine models and in clinical samples from human subjects (Aim 1); GIV's impact on liver fibrosis and pro- and antifibrotic signaling programs in HSCs and KCs downstream of fibrogenic receptors, e.g., TGF?R, PDGFR and CCRs and on cellular processes e.g., collagen production, apoptosis, chemotaxis, and proliferation will be interrogated by inducing liver injury in wild-type and HSC/KC-specific GIV- /- mice and HSCs/KCs isolated from them, respectively (Aim 2); if the Gi-GIV complex is required for liver fibrosis, and whether targeted inhibition of the Gi-GIV interface could serve as a strategy to inhibit and/or reverse fibrosis will be interrogated in murine models of cirrhosis using highly specific small molecule inhibitors of the interface for targeted disruption of the functional complex in the liver (Aim 3); and finally, whether the abundance of GIV in liver biopsies can predict the progression to cirrhosis and thereby, serve as a prognostic marker will be evaluated in a historic cohort of human subjects with chronic viral hepatitis who had a variable time-line to advanced fibrosis and cirrhosis (Aim 4). Insights gained will elucidate the role of this novel Gi-GIV signaling complex i liver fibrosis from a molecular and cellular level, to whole animal level, and finally, to the leve of its broader implications in a human liver cirrhosis, and help determine if the complex could serve as a marker and as a therapeutic target, thereby presenting an opportunity for personalized medicine.

描述（由申请人提供）：由过量饮酒、病毒性肝炎、自身免疫性疾病和非酒精性脂肪性肝炎（NASH）引起的肝纤维化可进展为肝硬化及其多种并发症，并在全世界范围内造成巨大的医疗负担。其特点是生长因子受体酪氨酸激酶 (RTK) 和 GPCR 的 Gi 偶联趋化因子/细胞因子家族（例如 CCR）信号异常，在慢性损伤/炎症的刺激下，导致细胞外基质过度沉积，主要由活化的细胞因子产生。肝星状细胞（HSC）。为了响应纤维化刺激，静止的 HSC 转化为产生胶原蛋白的肌成纤维细胞样细胞。这一关键转变的关键促纤维化触发因素是 PI3K-Akt 通路，而关键的抗纤维化刺激物是 cAMP。 PI3K-Akt 通路对于 KC 的趋化作用也至关重要，KC 在肝纤维化中发挥着另一组关键作用。协调驱动不受限制的 PI3K-Akt 信号传导并同时减少这些不同类别受体下游的 cAMP，最终导致肝纤维化的精确机制仍然未知。最近，一种由 G 蛋白亚基 G?i 和 GIV 组成的新型信号复合物已被鉴定，其非受体 GEF 已被鉴定，可抑制 cAMP 产生，并增强由生长因子受体受体和 GPCR 启动的 PI3K-Akt 信号。据推测，这些由 GIV-Gi 信号轴驱动的信号程序会激活 HSC 和 KC 并驱动肝纤维化，而抑制该轴可能会阻止和逆转纤维化。为了检验这一假设，将在小鼠模型和人类受试者的临床样本中研究急性和慢性肝损伤过程中 GIV 的表达、翻译后修饰和 G 蛋白结合特性（目标 1）； GIV 对肝纤维化以及纤维化受体（例如 TGFβR、PDGFR 和 CCR）下游 HSC 和 KC 中的促纤维化和抗纤维化信号转导程序以及对细胞过程（例如胶原蛋白生成、细胞凋亡、趋化性和增殖）的影响将通过诱导来探究分别对野生型和 HSC/KC 特异性 GIV- /- 小鼠以及从中分离出的 HSC/KC 进行肝损伤（目的2);肝纤维化是否需要 Gi-GIV 复合物，以及 Gi-GIV 界面的靶向抑制是否可以作为抑制和/或逆转纤维化的策略，将在小鼠肝硬化模型中使用高度特异性的小分子抑制剂进行研究用于有针对性地破坏肝脏功能复合物的界面（目标 3）；最后，将在历史上患有慢性病毒性肝炎的人类受试者队列中评估肝活检中 GIV 的丰度是否可以预测肝硬化的进展，从而作为预后标志物，这些受试者具有不同的晚期纤维化时间线和肝硬化（目标 4）。获得的见解将阐明这种新型 Gi-GIV 信号复合物在肝纤维化中的作用，从分子和细胞水平到整个动物水平，最后到其对人类肝硬化的更广泛影响的水平，并帮助确定是否复合物可以作为标记物和治疗靶点，从而为个性化医疗提供了机会。