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）在引起纤维化疾病中的作用。 CTGF是一种高度促纤维化的分子，其在迄今为止检查的所有纤维化病变中过表达。 它被转化生长因子β（TGF-β）转录激活，并介导许多以前归因于TGF-β的基质诱导特性。 该提案中描述的研究集中在CTGF在肝纤维化中的作用，包括与酒精滥用有关的作用。 初步数据显示，CTGF在纤维化肝脏中过度表达，并且由肝星状细胞（HSC）产生，肝星状细胞是主要的纤维化细胞类型，其响应于TGF-β并且作为活化的函数。 HSC显示出响应于CTGF的增强的粘附和α平滑肌肌动蛋白水平。 此外，乙醇及其致纤维化代谢物乙醛刺激成纤维细胞中的CTGF转录。 我们的假设是，CTGF在肝脏中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HSC中CTGF的调控机制，包括TGF-β和乙醛的作用（刺激HSC和CTGF产生）以及视黄酸和TNF-α（其抑制HSC功能和CTGF产生）;（2）通过检测肝星状细胞DNA合成、分裂、基质代谢、维生素A含量，用各种团块形式处理或过表达的HSC中的粘附（10 kDa，16- 20 kDa，38 kDa）的CTGF，这些CTGF在体内天然存在并且是体外维持的HSC的产物，并且确定CTGF刺激的激酶在这些过程中的作用;以及（3）制备用于将CTGF基因递送到体内肝脏中的重组腺相关病毒，以直接建立10 kDa和38 kDa 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、信号传导机制和蛋白质结构等方面明确CTGF的致纤维化特性。 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，纤维化是美国45%死亡的原因。

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.