Collagen Transcription and Lung Fibrosis

胶原蛋白转录和肺纤维化

• 批准号: 6980463
• 负责人: BARBARA Davis SMITH
• 金额: $ 40.38万
• 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: 2001-07-01 至 2010-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6980463
• 关键词: MHC class II antigen; collagen; fibrogenesis; gene induction /repression; gene mutation; genetic transcription; genetically modified animals; immunotherapy; inflammation; interferon gamma; laboratory mouse; lung injury; nonhuman therapy evaluation; protein biosynthesis; protein localization; protein protein interaction; pulmonary fibrosis /granuloma; transcription factor; transforming growth factors

DESCRIPTION (provided by applicant): Certain lung injuries induce large increases in connective tissue content, particularly collagen, resulting in pulmonary fibrosis. During injury, inflammation, and repair, cells are exposed to molecules such as interferon-gamma (IFN-gamma) and transforming growth factor-beta (TGF-beta) that are released by inflammatory cells and regulate production of collagen. Collagen type I transcription is activated after inflammatory response to injury in order to repair damage. This process is followed by repression of transcription. Without transcriptional repression, progressive fibrosis results in the lung. We hypothesize that changes in transcription require multiple proteins interacting cooperatively to alter transcription and chromatin structure in response to cytokine signals. During the last funding period, we focused on the mechanism of IFN-gamma induced repression of collagen transcription. IFN-gamma increases expression of regulatory factor for X-box 5 (RFX5) complex proteins which localizes in the nucleus, interacts with the collagen gene transcriptional start site and represses collagen synthesis. Class II transactivator (CIITA) dramatically increases early during IFN-gamma treatment and interacts with RFX5 complex. IFN-gamma-induced CIITA protein is responsible for both activation of major histocompatibility complex (MHC) and repression of collagen gene expression. Clinical trials for interstitial pulmonary fibrosis with IFN-gamma have been unsuccessful due to increased inflammatory response. We hypothesize that RFX5/CIITA proteins may be responsible for activating inflammatory responses while repressing collagen through separate CIITA transactivation and repression domains. We have compelling evidence that many proteins including co-repressors bind to the collagen start site during repression. Activation by agents such as TGF-beta may recruit different proteins to the collagen gene. The specific aims are to; 1) Determine the proteins interacting with the collagen start site during IFN-gamma treatment. 2) Examine the functional interactions of activation proteins binding upstream in the promoter with RFX family of proteins with and without TGF-beta. 3) Examine bleomycin induced fibrosis in animals with CIITA mutations and/or deficiencies with and without collagen-promoter-CAT constructs to investigate inflammation and collagen transcriptional regulation during fibrosis.

描述（由申请人提供）：某些肺损伤会导致结缔组织含量（尤其是胶原蛋白）大幅增加，从而导致肺纤维化。 在损伤、炎症和修复过程中，细胞会暴露于干扰素-γ (IFN-γ) 和转化生长因子-β (TGF-β) 等分子中，这些分子由炎症细胞释放并调节胶原蛋白的产生。 I 型胶原蛋白转录在对损伤产生炎症反应后被激活，以修复损伤。该过程之后是转录抑制。如果没有转录抑制，肺部就会发生进行性纤维化。 我们假设转录的变化需要多种蛋白质协同相互作用来改变转录和染色质结构以响应细胞因子信号。 在上一次资助期间，我们重点研究了 IFN-γ 诱导的胶原蛋白转录抑制的机制。 IFN-γ 增加 X-box 5 (RFX5) 复合蛋白调节因子的表达，该蛋白位于细胞核中，与胶原蛋白基因转录起始位点相互作用并抑制胶原蛋白合成。 II 类反式激活因子 (CIITA) 在 IFN-γ 治疗早期显着增加，并与 RFX5 复合物相互作用。 IFN-γ 诱导的 CIITA 蛋白负责主要组织相容性复合体 (MHC) 的激活和胶原蛋白基因表达的抑制。 由于炎症反应增加，用 IFN-γ 治疗间质性肺纤维化的临床试验尚未成功。 我们假设 RFX5/CIITA 蛋白可能负责激活炎症反应，同时通过单独的 CIITA 反式激活和抑制域抑制胶原蛋白。 我们有令人信服的证据表明，包括共阻遏物在内的许多蛋白质在阻遏过程中与胶原蛋白起始位点结合。 TGF-β 等物质的激活可能会将不同的蛋白质招募到胶原蛋白基因中。 具体目标是： 1) 确定 IFN-gamma 治疗期间与胶原蛋白起始位点相互作用的蛋白质。 2) 检查启动子上游结合的激活蛋白与有或没有 TGF-β 的 RFX 蛋白家族的功能相互作用。 3) 在有或没有胶原蛋白启动子-CAT构建体的情况下，检查具有CIITA突变和/或缺陷的动物中博来霉素诱导的纤维化，以研究纤维化过程中的炎症和胶原蛋白转录调节。