TYPE I COLLAGEN REGULATION IN PULMONARY FIBROSIS

肺纤维化中 I 型胶原蛋白的调节

• 批准号: 6411235
• 负责人: Ronald Howard Goldstein
• 金额: $ 30.86万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-01-22 至 2002-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6411235
• 关键词: clinical research; collagen; collagen disorder; cytokine receptors; drug screening /evaluation; genetic promoter element; genetic regulatory element; genetic transcription; genetically modified animals; growth factor receptors; human subject; laboratory mouse; molecular pathology; prednisone; prostaglandin E; prostaglandin analogs; protein biosynthesis; protein kinase; pulmonary fibrosis /granuloma; receptor; receptor binding; receptor expression; regulatory gene; retinoids; transforming growth factors

Excess accumulation of type I collagen is key feature of the fibrosing lung diseases, causing disruption of normal pulmonary function. This increase in type I collagen likely results from a complex interplay of effector substances which activate or inhibit collagen formation by lung fibroblasts. We have a long-standing interest in the mechanisms whereby key regulatory molecules such as transforming growth factor-beat(TGF- beta), prostaglandin E2 (PGE2), and retinoic acid (RA) affect type I collagen accumulation. We believe that the examination of interactions between these mediators will suggest possible strategies for modulating type I collagen accumulation in the lung. TGF-beta activates transcription via signals transmitted by two signalling receptors (type I and type II), each containing cytoplasmic serine-threonine kinase domains. We found that TGF-beta stimulates and PGE2 inhibits type I receptor mRNA levels. These findings may explain, in part, the sustained elevation of type I collagen formation induced by TGF-beta and the selective inhibition of TGF-beta action on lung fibroblasts by PGE2. We have cloned the type I TGF-beta receptor promoter. In the first part of this proposal, we will employ the human type I receptor promoter to identify the genetic mechanisms whereby TGF-beta and PGE2 regulate type I receptor promoter activity. Subsequently, by over-expressing a kinase deficient or a wild- type I receptor cDNA, we will characterize the precise relation between type I receptor expression and alpha 1(I) promoter activity. Using an alpha 1(I) collagen promoter construct, we plan to identify the cis-acting elements and trans-acting factors which mediate the decrease in type I collagen gene transcription by PGE2 and RA. We hypothesize that the inhibitory effect of PGE2 on type I collagen formation and TGF-beta type I receptor expression indicates that misoprostol, a PGE1 analog, may have therapeutic value in pulmonary fibrosis. Notably, we found that misoprostol inhibited basal and TGF-beta-induced collagen formation by lung fibroblasts in vitro. Thus, as the final part of this proposal we will determine the effect of prednisone with or without immunotherapy, or misoprostol on collagen biosynthesis in patients with fibrosing lung diseases. We will assess collagen biosynthesis by measuring pro-collagen peptides, lysyl oxidase activity, and collagen metabolites. Overall, the studies outlined in this component of the SCOR proposal will provide key information regarding the modulation of type I collagen accumulation in pulmonary fibrosis.

I 型胶原蛋白的过量积累是纤维化的关键特征 肺部疾病，导致正常肺功能中断。 这 I 型胶原蛋白的增加可能是由于以下因素复杂的相互作用造成的 激活或抑制肺胶原形成的效应物质 成纤维细胞。 我们对机制有着长期的兴趣 关键调控分子如转化生长因子-beat(TGF- beta)、前列腺素 E2 (PGE2) 和视黄酸 (RA) 影响 I 型 胶原蛋白堆积。 我们认为，相互作用的检验 这些中介者之间的关系将提出可能的调节策略 I 型胶原蛋白在肺部积聚。 TGF-β 激活 通过两个信号受体（I 型 和 II 型），每个都包含细胞质丝氨酸-苏氨酸激酶结构域。 我们发现 TGF-β 刺激 I 型受体 mRNA，PGE2 抑制 I 型受体 mRNA 水平。这些发现可以部分解释为什么 TGF-β诱导的I型胶原形成及其选择性抑制 PGE2 作用于肺成纤维细胞的 TGF-β 作用。我们克隆了I型 TGF-β受体启动子。在本提案的第一部分中，我们将 使用人类 I 型受体启动子来鉴定遗传 TGF-β 和 PGE2 调节 I 型受体启动子的机制 活动。 随后，通过过度表达激酶缺陷或野生激酶 I 型受体 cDNA，我们将表征之间的精确关系 I 型受体表达和 alpha 1(I) 启动子活性。使用 α 1(I) 胶原蛋白启动子构建体，我们计划鉴定顺式作用 介导 I 型减少的元素和反式作用因子 PGE2 和 RA 的胶原蛋白基因转录。我们假设 PGE2对I型胶原形成和TGF-β型的抑制作用 I 受体表达表明米索前列醇（一种 PGE1 类似物）可能具有 对肺纤维化有治疗价值。 值得注意的是，我们发现 米索前列醇通过以下方式抑制基础胶原蛋白和 TGF-β 诱导的胶原蛋白形成 体外肺成纤维细胞。因此，作为该提案的最后一部分，我们 将确定泼尼松联合或不联合免疫治疗的效果，或 米索前列醇对肺纤维化患者胶原生物合成的影响 疾病。 我们将通过测量前胶原蛋白来评估胶原蛋白的生物合成 肽、赖氨酰氧化酶活性和胶原代谢物。总体而言， SCOR 提案的这一部分中概述的研究将提供关键的 有关调节 I 型胶原蛋白积累的信息 肺纤维化。