Connective Tissue Growth Factor in Hepatic Fibrosis

广泛的长期目标是确定结缔组织生长因子（CTGF）在纤维化疾病中的作用。CTGF是一种高度促纤维化的分子，迄今为止在所有的纤维化病变中都有过表达。它被转化生长因子- β (tgf - β)转录激活，并介导许多先前归因于tgf - β的基质诱导特性。本提案中描述的研究主要关注CTGF在肝纤维化中的作用，包括与酒精滥用相关的研究。初步数据显示，CTGF在纤维化肝脏中过度表达，由主要的纤维化细胞类型肝星状细胞（HSCs）产生，既可响应tgf - β，也可作为激活功能。造血干细胞在CTGF的作用下表现出增强的粘附和α平滑肌肌动蛋白水平。此外，乙醇及其成纤维代谢产物乙醛刺激成纤维细胞中的CTGF转录。我们的假设是肝脏中CTGF的局部上调驱动了纤维化反应，包括酒精引发的纤维化反应。我们的具体目标是：(1)确定CTGF在HSC中的调节机制，包括tgf - β和乙醛（刺激HSC和CTGF的产生）以及维甲酸和tnf - α（抑制HSC功能和CTGF的产生）所起的作用；(2)通过检测体内自然产生的、体外维持的产物CTGF的不同质量形式（1OkDa、16-20kDa、38kDa）处理或过表达的HSC的HSC DNA合成、分裂、基质代谢、维生素A含量和粘附，确定CTGF刺激的激酶在这些过程中的作用，确定CTGF对HSC功能的影响；(3)制备重组腺相关病毒，在体内将CTGF基因导入肝脏，直接建立10kda和38kDa CTGF刺激肝纤维化的能力。这些研究将从CTGF的调控、生物学特性、信号机制和蛋白结构等方面明确其成纤维特性。此外，这些研究将有助于确定CTGF是否是治疗纤维化的治疗靶点，在美国，纤维化是45%死亡的一个促成因素。

The broad long-term objectives are to establish the role of connective tissue growth factor (CTGF) in causing fibrotic disease. CTGF is a highly pro-fibrogenic molecule which is over- expressed in all fibrotic lesions examined to date. It is transcriptionally activated by transforming growth factor-beta (TGF-beta) and mediates many of the matrix-inducing properties that have previously been attributed to TGF-beta. The studies described in this proposal focus on the role of CTGF in liver fibrosis, including that related to alcohol abuse. Preliminary data show that CTGF is over-expressed in fibrotic livers and is produced by hepatic stellate cells (HSCs), the principal fibrogenic cell type, both in response to TGF-beta and as a function of activation. HSCs show enhanced adhesion and levels of alpha smooth muscle actin in response to CTGF. In addition, ethanol and its fibrogenic metabolite, acetaldehyde, stimulate CTGF transcription in fibroblasts. Our hypothesis is that local up-regulation of CTGF in the liver drives the fibrogenic response, including that initiated by alcohol. Our Specific Aims are (1) To determine mechanisms of CTGF regulation in HSCs, including the role played by TGF-beta and acetaldehyde (which stimulate HSCs and CTGF production) as well as retinoic acid and TNF-alpha (which inhibit HSC function and CTGF production); (2) To determine the effects of CTGF on HSC function by examining HSC DNA synthesis, division, matrix metabolism, vitamin A content, and adhesion in HSCs treated with or over-expressing various mass forms (1OkDa, 16-20kDa, 38kDa) of CTGF which occur naturally in vivo and which are a product of HSCs maintained in vitro, and to determine the role of CTGF-stimulated kinases in these processes; and (3) To produce recombinant adeno-associated viruses for the delivery of the CTGF gene into the liver in vivo to directly establish the ability of 10 kDa and 38kDa CTGF to stimulate liver fibrosis. These studies will define the fibrogenic properties of CTGF in terms of its regulation, biological properties, signaling mechanisms and protein structure. In addition, these studies will help establish whether CTGF is a therapeutic target for treating fibrosis, which is a contributing factor in 45 percent of deaths in the USA.