Regulation of Collagen Formation in Pulmonary Fibrosis

肺纤维化中胶原蛋白形成的调节

• 批准号: 6920783
• 负责人: Ronald Howard Goldstein
• 金额: $ 36.34万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6920783
• 关键词: 3T3 cells; G protein; actins; antisense nucleic acid; apoptosis; biological signal transduction; bleomycin; cell differentiation; cell morphology; collagen; fibroblasts; fibrogenesis; gene expression; genetic regulatory element; integrins; laboratory mouse; lung injury; messenger RNA; phosphatidylinositol 3 kinase; prostaglandins; protein kinase; protein tyrosine kinase; pulmonary fibrosis /granuloma; smooth muscle; tumor necrosis factor alpha

The activation of myofibroblast is a central feature of interstitial pulmonary fibrosis. The objective of this proposal is to examine the regulation of the lung myofibroblast phenotype with an emphasis on the signal transduction pathways utilized by these cells to increase matrix deposition. Following lung injury in vivo, fibroblasts in the interstitial wall display a myofibroblast phenotype with increased expression of alpha-smooth muscle actin and alpha1(I) collagen mRNA. We have shown that prostaglandin E2 (PGE2) down-regulated steady state levels for alpha1(I) collagen, connective tissue growth factor and alpha- smooth muscle actin mRNA. PGE2 also stimulated Ca2+ activated K+ channels that decrease cell volume, and sensitized the cells to death receptor mediated apoptosis. These results indicate that PGE2 inhibits expression of the myofibroblast phenotype and has significant anti-fibrogenic properties. Preliminary data indicate that treatment of fibroblasts with PGE2 causes decreases in phosphatidylinositiol 3-kinase (PI-3K) as assessed by levels of phosphorylated protein kinase B/Akt. Employing inhibitors to PI-3K and mutant Akt constructs, we find that the activity of the PI-3K system regulates the stability of the alpha1(I) collagen mRNA. We hypothesize that fibroblast activation and the development of the myofibroblast phenotype involves an up- regulation in the activity of the PI-3K signal transduction pathways which in turn up-regulates alpha1(I) collagen and alpha- smooth muscle actin mRNA expression. PGE2 down-regulates these processes by affecting PI-3K activity and decreasing cell hydration. We plan to use cellular and molecular approaches to test our hypothesis in vitro and in vivo. Our studies will provide new insights into the regulation of the myofibroblast and suggest new therapeutic options for the treatment of pulmonary fibrosis.

肌成纤维细胞的激活是间质性肺纤维化的核心特征。 该提案的目的是检查肺肌成纤维细胞表型的调节，重点是这些细胞用来增加基质沉积的信号转导途径。 体内肺损伤后，间质壁中的成纤维细胞表现出肌成纤维细胞表型，其中 α-平滑肌肌动蛋白和 α1(I) 胶原蛋白 mRNA 的表达增加。 我们已经证明前列腺素 E2 (PGE2) 下调 α1(I) 胶原蛋白、结缔组织生长因子和 α-平滑肌肌动蛋白 mRNA 的稳态水平。 PGE2 还刺激 Ca2+ 激活 K+ 通道，从而减少细胞体积，并使细胞对死亡受体介导的细胞凋亡敏感。 这些结果表明 PGE2 抑制肌成纤维细胞表型的表达并具有显着的抗纤维形成特性。 初步数据表明，通过磷酸化蛋白激酶 B/Akt 水平评估，用 PGE2 处理成纤维细胞会导致磷脂酰肌醇 3-激酶 (PI-3K) 减少。 使用 PI-3K 和突变 Akt 构建体的抑制剂，我们发现 PI-3K 系统的活性调节 alpha1(I) 胶原蛋白 mRNA 的稳定性。 我们假设成纤维细胞活化和肌成纤维细胞表型的发展涉及 PI-3K 信号转导途径活性的上调，进而上调 α1(I) 胶原和 α-平滑肌肌动蛋白 mRNA 的表达。 PGE2 通过影响 PI-3K 活性和减少细胞水合作用来下调这些过程。 我们计划使用细胞和分子方法在体外和体内检验我们的假设。 我们的研究将为肌成纤维细胞的调节提供新的见解，并为治疗肺纤维化提出新的治疗选择。