TYPE I COLLAGEN REGULATION IN PULMONARY FIBROSIS

I型胶原蛋白的过度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的复杂相互作用 激活或抑制肺胶原形成的效应物质 成纤维细胞 我们长期关注的是， 关键的调节分子，如转化生长因子-β（TGF-β）， β）、前列腺素E2（PGE2）和维甲酸（RA）影响I型糖尿病。 胶原蛋白积聚。 我们认为，对相互作用的研究 这些介质之间的关系将提出可能的策略， I型胶原在肺中的积聚。 TGF-β激活 通过两个信号受体（I型）传递的信号进行转录 和II型），每一个都含有细胞质丝氨酸-苏氨酸激酶结构域。 我们发现TGF-β刺激和PGE2抑制I型受体mRNA， 程度.这些发现可以部分解释， TGF-β诱导的I型胶原形成及其选择性抑制 TGF-β通过PGE2对肺成纤维细胞的作用。我们克隆了I型 TGF-β受体启动子。在本提案的第一部分，我们将 使用人I型受体启动子来鉴定基因 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型或野生型， I型受体cDNA，我们将描述精确的关系， I型受体表达和α 1（I）启动子活性。使用 α 1（I）胶原蛋白启动子构建，我们计划确定顺式作用 元素和反式作用因子介导的减少I型 PGE2和RA的胶原基因转录。我们假设 前列腺素E_2对I型胶原形成和TGF-β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 肺纤维化的治疗价值。 值得注意的是， 米索前列醇抑制基础和TGF-β诱导的胶原蛋白形成， 体外培养肺成纤维细胞。因此，作为本提案的最后一部分， 将决定强的松是否有免疫治疗的效果，或 米索前列醇对肺纤维化患者胶原合成的影响 疾病 我们将通过测量前胶原来评估胶原的生物合成 肽、赖氨酰氧化酶活性和胶原代谢物。总体看 在SCOR建议的这一部分中概述的研究将提供关键的 关于调节I型胶原积累的信息， 肺纤维化

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.