Integrin-collagen signaling and control of fibroblast proliferation

整合素胶原信号传导和成纤维细胞增殖的控制

• 批准号: 8269781
• 负责人: CRAIG A HENKE
• 金额: $ 16.21万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-04 至 2014-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8269781
• 关键词: Alveolar; Alveolar wall; Apoptosis; Applications Grants; Architecture; Area; Behavior; Bleomycin; Bone Marrow; Cells; Chronic; Collagen; Collagen Type I; Complex; Defect; Deposition; Disease; Extracellular Matrix; Facies; Feedback; Fibroblasts; Fibronectins; Fibrosis; Goals; Growth; Hamman-Rich syndrome; Healed; Health; In Vitro; Inflammation; Inflammatory; Injury; Integrins; Interstitial Lung Diseases; Knockout Mice; Knowledge; Left; Lesion; Ligation; Lipids; Lung; Lung diseases; Membrane; Mesenchymal; Methodology; Molecular; Mus; Myofibroblast; Nature; Normal tissue morphology; PTEN gene; Pathologic; Pathway interactions; Phenotype; Phosphoric Monoester Hydrolases; Phosphotransferases; Physiological; Process; Proliferating; Protein Biosynthesis; Protein Phosphatase 2A Regulatory Subunit PR53; Proteins; Pulmonary Fibrosis; Regulation; Role; Seminal; Sentinel; Signal Pathway; Signal Transduction; Staging; Structure of parenchyma of lung; Testing; Tissues; Tumor Suppressor Proteins; Validation; Wild Type Mouse; base; caveolin 1; effective therapy; fibrogenesis; healing; in vivo; lung development; lung injury; lung repair; mRNA Expression; mTOR Inhibitor; member; protein expression; repaired; response; restraint; therapeutic target; tissue repair; transcription factor

DESCRIPTION (provided by applicant): Idiopathic Pulmonary Fibrosis (IPF) is a progressive, fatal fibrotic lung disease for which there is no effective therapy. The sentinel morphological lesion is the fibroblastic focus, which is composed of myofibroblasts in a type I collagen rich matrix. Prima facie evidence supports the critical role for myofibroblasts in the relentless progression of IPF given that this is the cell that proliferates and deposits collagen in the alveolar wall. Although studies strongly support the notion that IPF fibroblasts display a distinct pathological phenotype, large gaps in knowledge remain regarding differences between the pathological nature of IPF fibroblasts responsible for progressive fibrosis and the physiologic function of myofibroblasts essential for normal lung repair. The objective of this proposal is to characterize the molecular processes underlying the pathological nature of IPF fibroblasts. Seminal studies have demonstrated that polymerized type I collagen acts as a negative regulator of fibroblast proliferation. Consistent with this, we have found that normal lung fibroblast proliferation is inhibited by polymerized collagen. In contrast, we have found that IPF fibroblasts have escaped this restraint. Our mechanistic studies of this phenomenon point to abnormalities in ¿1 integrin signaling in response to ligation with type I collagen. We have discovered that integrin-ECM interaction regulates PTEN expression and activity. PTEN is a phosphatase whose baseline activity is constitutively high. It functions as a tumor suppressor by negatively regulating proliferation by repressing the integrin-phosphoinositol 3-kinase (PI3K)/Akt signaling pathway. When normal lung fibroblasts are cultured on polymerized collagen, we have found that PTEN activity remains high. In contrast, when IPF fibroblasts are cultured on polymerized collagen PTEN activity is inappropriately low leaving the PI3K/Akt signaling pathway unrestrained and removing one of the major physiological negative feedback signals regulating proliferation. This enables IPF fibroblasts to circumvent the negative regulatory effects of polymerized collagen. We hypothesize that: ¿1 integrin-type I collagen interaction results in aberrant regulation of PTEN. This leads to unrestrained PI3K/Akt/S6K1 activity and underlies the pathologic proliferation of IPF fibroblasts on polymerized collagen. To test our hypothesis we will: Aim 1. Determine the role of the PI3K/Akt/S6K1-PTEN signaling axis in enabling IPF fibroblasts to elude the negative proliferative effects of polymerized type I collagen. Aim 2. Define the molecular basis for regulation of PTEN and the PI3K/Akt signal pathway in control and IPF lung fibroblasts by ¿1 integrin-type I collagen interaction. Aim 3. Validation of in vitro studies implicating abnormal function of the ¿1 integrin PI3K/Akt/S6K1-PTEN signaling axis in IPF fibrogenesis by in vivo methodology. PUBLIC HEALTH RELEVANCE: Idiopathic pulmonary fibrosis (IPF) is a chronic, lethal interstitial lung disease. The sentinel morphological lesion is the fibroblastic focus, which is composed of fibroblasts embedded in a type I collagen rich matrix. Seminal studies have demonstrated that polymerized type I collagen acts as a negative regulator of fibroblast proliferation. We have discovered that IPF fibroblasts have escaped this restraint. Our mechanistic studies of this phenomenon point to aberrant proliferation signaling through the ¿1 integrin, involving the downstream phosphoinositol 3-kinase/Akt - PTEN axis. The objective of this grant application is to characterize the molecular mechanism by which ¿1 integrin-collagen interaction results in abnormal proliferative signaling in IPF fibroblasts. It is our goal to uncover those components of the myofibroblast cellular machinery that result in unrelenting fibrosis in IPF, and in proper tissue healing under normal circumstances. Identifying key regulatory nodes controlling the pathologic behavior of IPF fibroblasts may provide molecular therapeutic targets to limit the progressive fibrosis that characterizes IPF.

描述（由申请人提供）：特发性肺纤维化（IPF）是一种进行性、致命性的纤维化肺病，目前尚无有效的治疗方法。前哨形态学病变是成纤维细胞灶，它由富含 I 型胶原的基质中的肌成纤维细胞组成。初步证据支持肌成纤维细胞在 IPF 的持续进展中发挥关键作用，因为肌成纤维细胞是在肺泡壁中增殖和沉积胶原的细胞。尽管研究强烈支持 IPF 成纤维细胞表现出独特的病理表型的观点，但对于导致进行性纤维化的 IPF 成纤维细胞的病理性质与正常肺修复所必需的肌成纤维细胞的生理功能之间的差异，仍然存在巨大的知识差距。该提案的目的是表征 IPF 成纤维细胞病理本质的分子过程。开创性研究表明，聚合 I 型胶原蛋白可作为成纤维细胞增殖的负调节剂。与此一致的是，我们发现正常的肺成纤维细胞增殖受到聚合胶原蛋白的抑制。相比之下，我们发现IPF成纤维细胞却逃脱了这种限制。我们对这种现象的机制研究表明，与 I 型胶原连接后，¿1 整合素信号传导出现异常。我们发现整合素-ECM 相互作用调节 PTEN 表达和活性。 PTEN 是一种基线活性较高的磷酸酶。它通过抑制整合素磷酸肌醇 3 激酶 (PI3K)/Akt 信号通路来负向调节增殖，从而发挥肿瘤抑制剂的作用。当正常肺成纤维细胞在聚合胶原上培养时，我们发现 PTEN 活性仍然很高。相反，当 IPF 成纤维细胞在聚合胶原蛋白上培养时，PTEN 活性过低，导致 PI3K/Akt 信号通路不受限制，并消除了调节增殖的主要生理负反馈信号之一。这使得 IPF 成纤维细胞能够规避聚合胶原蛋白的负面调节作用。我们假设： 1 整合素-I 型胶原蛋白相互作用导致 PTEN 的异常调节。这导致 PI3K/Akt/S6K1 活性不受限制，是聚合胶原蛋白上 IPF 成纤维细胞病理性增殖的基础。为了检验我们的假设，我们将： 目标 1. 确定 PI3K/Akt/S6K1-PTEN 信号轴在使 IPF 成纤维细胞逃避聚合 I 型胶原蛋白的负面增殖作用中的作用。目标 2. 定义通过 ¿1 整合素与 I 型胶原相互作用调节对照和 IPF 肺成纤维细胞中 PTEN 和 PI3K/Akt 信号通路的分子基础。目标 3. 通过体内方法验证体外研究表明 1 整合素 PI3K/Akt/S6K1-PTEN 信号轴在 IPF 纤维形成中的异常功能。公共卫生相关性：特发性肺纤维化 (IPF) 是一种慢性致命性间质性肺疾病。前哨形态学病变是成纤维细胞灶，它由嵌入富含 I 型胶原的基质中的成纤维细胞组成。开创性研究表明，聚合 I 型胶原蛋白可作为成纤维细胞增殖的负调节剂。我们发现IPF成纤维细胞已经逃脱了这种限制。我们对此现象的机制研究表明，通过 ¿1 整合素存在异常增殖信号，涉及下游磷酸肌醇 3-激酶/Akt - PTEN 轴。该资助申请的目的是确定 1 整合素-胶原蛋白相互作用导致 IPF 成纤维细胞异常增殖信号传导的分子机制。我们的目标是揭示肌成纤维细胞机制的那些成分，这些成分会导致 IPF 中持续的纤维化，并在正常情况下导致适当的组织愈合。识别控制 IPF 成纤维细胞病理行为的关键调节节点可能提供分子治疗靶点，以限制 IPF 特征的进行性纤维化。