TGF-beta receptor signaling in scleroderma

硬皮病中的 TGF-β 受体信号传导

• 批准号: 7086368
• 负责人: MARIA TROJANOWSKA
• 金额: $ 24.66万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-15 至 2008-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7086368
• 关键词: autocrine; binding proteins; biological signal transduction; biopsy; collagen; cytokine; extracellular matrix; extracellular matrix proteins; fibroblasts; fibrogenesis; growth factor receptors; human subject; insulinlike growth factor; molecular pathology; patient oriented research; protein isoforms; protein structure function; protooncogene; systemic scleroderma; tissue /cell culture; transforming growth factors

DESCRIPTION (provided by applicant): Organ fibrosis, a major pathological manifestation of scleroderma (SSc), is the result of excessive deposition of collagen I and other extracellular matrix (ECM) proteins. Despite the significant progress that has been made towards unraveling the physiological and pathological mechanisms involved in regulation of collagen genes, a full understanding of these processes is still lacking. In particular, very little is currently known about the molecular mechanism responsible for constitutive upregulation of ECM proteins by SSc fibroblasts. Such knowledge is critical for development of suitable targets for therapeutic intervention. During the last funding period we proposed to test the hypothesis that autocrine TGF-B signaling through overexpression of TGFB receptors is at least partially responsible for the SSc phenotype. To test this hypothesis we blocked TGF-B signaling by overexpressing a kinase-deficient TGF-B receptor II (TBRIIdeltaK). Contrary to our expectations, SSc fibroblasts were mainly unresponsive to this treatment with regard to collagen production. On the other hand, this treatment resulted in a significant downregulation of the ECM production in healthy skin fibroblasts. These results led to a revision of our hypothesis and prompted us to investigate alternative mechanisms that may be responsible for the SSc phenotype. To investigate TGF-B independent pathways, we have focused on CTGF (connective tissue growth factor) and IGFBP5 (IGF binding protein 5). The current research proposal is based on our novel observations indicating that CTGF induction of ECM in human fibroblasts is dependent on insulin signaling and that IGFBP5 also stimulates collagen production by fibroblasts. We propose the following Specific Aims to test the hypothesis that interactions between TGF-B, CTGF, and insulin/IGF pathways are involved in the regulation of the SSc phenotype. In Specific Aim 1 we will continue to examine the role of the components of the TGF-B signaling pathway in the manifestation of the SSc phenotype. In Specific Aim 2 we will determine the role of the CTGF-mediated pathway in ECM production by SSc fibroblasts. We will delineate the mechanism of CTGF stimulation of the COL1A2 promoter and characterize the components of the insulin/IGF signaling pathway that contribute to CTGF induction of collagen. In Specific Aim 3 we will determine the mechanism of IGFBP5 stimulation of collagen production by SSc and healthy fibroblasts. We will analyze expression patterns of IGFBPs in SSc and healthy fibroblasts and utilize purified IGFBP proteins and corresponding cDNAs to probe their role in collagen regulation by SSc and healthy fibroblasts. In Specific Aim 4 we will examine the in vivo expression of the TGF-B receptor subunits, CTGF, and IGF/IGFBPs in SSc skin.

描述（由申请人提供）：器官纤维化，一种主要的病理学 硬皮病（SSc）的表现是过度沉积的结果 I 型胶原蛋白和其他细胞外基质 (ECM) 蛋白。尽管 在阐明生理学方面已取得重大进展 和涉及胶原蛋白基因调节的病理机制，完整的 对这些过程的了解仍然缺乏。特别是很少 目前已知负责组成的分子机制 SSc 成纤维细胞上调 ECM 蛋白。这些知识对于 制定合适的治疗干预目标。最后期间 我们提议在资助期间检验自分泌 TGF-B 的假设 通过过度表达 TGFB 受体的信号转导至少部分是 负责 SSc 表型。为了验证这一假设，我们阻断了 TGF-B 通过过度表达激酶缺陷型 TGF-B 受体 II (TBRIIdeltaK) 来发挥信号传导作用。 与我们的预期相反，SSc 成纤维细胞主要对此没有反应 与胶原蛋白产生有关的治疗。另一方面，这种治疗 导致健康皮肤中 ECM 的产生显着下调 成纤维细胞。这些结果导致我们的假设被修正并促使我们 研究可能导致 SSc 的替代机制 表型。为了研究 TGF-B 独立途径，我们重点关注 CTGF （结缔组织生长因子）和 IGFBP5（IGF 结合蛋白 5）。当前的研究提案基于我们的新观察结果，表明 CTGF 对人成纤维细胞 ECM 的诱导依赖于胰岛素信号传导 IGFBP5 还可以刺激成纤维细胞产生胶原蛋白。我们建议 以下具体目标是检验以下假设： TGF-B、CTGF 和胰岛素/IGF 途径参与 SSc 的调节 表型。在具体目标 1 中，我们将继续研究 SSc 表现中 TGF-B 信号通路的组成部分 表型。在具体目标 2 中，我们将确定 CTGF 介导的作用 SSc 成纤维细胞产生 ECM 的途径。我们将划定机制 CTGF 刺激 COL1A2 启动子并表征其成分 胰岛素/IGF信号通路有助于CTGF诱导 胶原。在具体目标 3 中，我们将确定 IGFBP5 的机制 刺激 SSc 和健康成纤维细胞产生胶原蛋白。我们将 分析 SSc 和健康成纤维细胞中 IGFBP 的表达模式， 利用纯化的 IGFBP 蛋白和相应的 cDNA 来探测它们在 SSc 和健康成纤维细胞对胶原蛋白的调节。在具体目标 4 中，我们将 检查 TGF-B 受体亚基、CTGF 和 SSc 皮肤中的 IGF/IGFBP。