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: 8473261
• 负责人: CRAIG A HENKE
• 金额: $ 15.43万
• 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 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8473261
• 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.

描述(申请人提供)：特发性肺纤维化(IPF)是一种进行性的、致命的纤维性肺部疾病，目前还没有有效的治疗方法。前哨形态病变为成纤维细胞灶，由富含I型胶原基质的肌成纤维细胞组成。初步证据支持肌成纤维细胞在IPF的持续发展中的关键作用，因为这是一种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，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，仍存在很大的认识空白。这项建议的目的是描述IPF成纤维细胞病理本质的分子过程。开创性研究表明，聚合的I型胶原对成纤维细胞的增殖起负调控作用。与此一致，我们发现聚合的胶原抑制了正常肺成纤维细胞的增殖。相反，我们发现IPF成纤维细胞逃脱了这种限制。我们对这一现象的机制研究指出，与I型胶原结扎时，整合素信号异常。我们发现整合素-ECM相互作用调节PTEN的表达和活性。PTEN是一种基础活性较高的磷酸酶。它通过抑制整合素-磷脂酰肌醇3-激酶(PI3K)/Akt信号通路，负向调节细胞增殖，发挥肿瘤抑制作用。当将正常肺成纤维细胞培养在聚合的胶原上时，我们发现PTEN活性仍然很高。相反，当IPF成纤维细胞被培养在聚合的胶原上时，PTEN的活性不适当地低，使得PI3K/Akt信号通路不受抑制，并消除了调节增殖的主要生理负反馈信号之一。这使得IPF成纤维细胞能够避开聚合胶原蛋白的负面调节作用。我们假设：1整合素-I型胶原相互作用导致PTEN的异常调节。这导致PI3K/Akt/S6K1活性不受抑制，是IPF成纤维细胞在聚合胶原上病理性增殖的基础。为了验证我们的假设，我们将：目的1.确定PI3K/Akt/S6K1-PTEN信号轴在使IPF成纤维细胞逃避聚合的I型胶原的负面增殖效应中的作用。目的2.明确1整合素-I型胶原相互作用对对照和特发性肺纤维化肺成纤维细胞PTEN和PI3K/Akt信号通路调控的分子基础。目的3.用体内方法学验证1整合素PI3K/Akt/S6K1-PTEN信号轴在特发性肺纤维化中功能异常的体外研究。