GROWTH FACTOR/CYTOKINE INTERACTIONS IN MESENCHYMAL CELLS

肠道慢性炎症诱导伤口愈合反应 特征在于间充质细胞的增殖和增加 细胞外基质（ECM）沉积。这种纤维化反应导致 狭窄和梗阻的并发症。有升高的表达 胰岛素样生长因子（IGF-I和IGF-II）在动物模型中的作用 慢性肠道炎症和在涉及肠道的患者， 克罗恩病（CD）。IGF刺激间充质细胞生长， 增强其他激素的增殖作用。我们假设 IGFs与细胞因子和ECM一起促进纤维化相关 通过刺激肠道成纤维细胞改变表型，增加CD 增殖和胶原沉积。为了验证这个假设，我们 我建议使用从人中分离的肠成纤维细胞系 结肠（CCD-18 Co）和正常的，培养的人肠成纤维细胞， 模型系统首先，我们将评估IGF-I单独和联合应用的效果。 与CD相关的其他生长因子和细胞因子联合， DNA合成和细胞数量、表型，如通过α-平滑判断 肌肌动蛋白和胶原沉积，通过胶原和胶原酶判断 基因表达和胶原蛋白的产生。接下来，我们将检查 IGF-I、bFGF协同作用的细胞内机制 和IL-1对细胞增殖的影响。这将包括类型的检查 I IGF受体和IGFBPs可能调节IGF反应性。在 此外，将使用转染方法来评估细胞因子的作用。 AP-1信号在介导IGF、bFGF、IL-1作用中的作用及其机制 交互.最后，我们将比较ECM提取的效果， 从狭窄处提取的ECM的效果的健康肠段 GD对DNA合成、细胞数量、分化、IGF表达和 对IGF的反应。

Chronic inflammation of the bowel induces a wound-healing response characterized by proliferation of mesenchymal cells and increased extracellular matrix (ECM) deposition. This fibrogenic response causes complications of stricture and obstruction. There is elevated expression of insulin-like growth factors (IGF-I and IGF-II) in animal models of chronic bowel inflammation and in the involved bowel of patients with Crohn's disease (CD). IGFs stimulate mesenchymal cell growth and potentiate proliferative actions of other hormones. We hypothesize that IGFs work together with cytokines and ECM to promote fibrosis associated with CD by stimulating enteric fibroblasts to change phenotype, increase proliferation and collagen deposition. To test this hypothesis, we propose to use an enteric fibroblast cell line isolated from the human colon (CCD-18Co) and normal, cultured human intestinal fibroblasts as model systems. First, we will assess the effects of IGF-I alone and in combination with other growth factors and cytokines implicated in CD on DNA synthesis and cell number, phenotype, as judged by alpha-smooth muscle actin, and collagen deposition, judged by collagen and collagenase gene expression and collagen production. Next, we will examine intracellular mechanisms underlying synergistic effects of IGF-I, bFGF and IL-1 on cell proliferation. This will include an examination of type I IGF receptor and IGFBPs that may modulate IGF responsiveness. In addition, a transfection approach will be used to assess the role of the AP-1 signaling in mediating IGF, bFGF, IL-1 action and their interactions. Finally, we will compare the effects of ECM extracted from healthy segment of bowel with the effects of ECM extracted from stricture of GD on DNA synthesis, cell number, differentiation, IGF expression and responsiveness to IGF.