Extracellular Matrix Regulation of Fibroblast Viability

成纤维细胞活力的细胞外基质调节

• 批准号: 7426960
• 负责人: CRAIG A HENKE
• 金额: $ 32.39万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-04 至 2009-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7426960
• 关键词: 1-Phosphatidylinositol 3-Kinase; 3-Dimensional; Address; Adhesions; Alveolar wall; Alveolus; Anatomy; Antibodies; Apoptosis; Architecture; Biological Process; Cell physiology; Cells; Cicatrix; Collagen; Collagen Type I; Cytochalasin D; Cytoskeleton; Data; Deposition; Disease; Disease regression; Ectopic Expression; Environment; Equilibrium; Extracellular Matrix; Fibroblasts; Fibronectins; Functional disorder; Gases; Gel; Hamman-Rich syndrome; ILK gene; In Vitro; Induction of Apoptosis; Injury; Integrins; Investigation; Lead; Ligation; Lung; Mediating; Modeling; Molecular; Myofibroblast; NR0B2 gene; Nocodazole; Normal tissue morphology; Organ; PTEN gene; PTK2 gene; Pathway interactions; Patients; Pattern; Phenotype; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Physiological; Process; Protein Dephosphorylation; Regulation; Research Personnel; Role; Signal Pathway; Signal Transduction; Signaling Molecule; Surface; Tissues; Transcriptional Activation; Up-Regulation; Wound Healing; in vivo; insight; integrin-linked kinase; lung injury; novel; programs; repaired; response; restoration; wound

DESCRIPTION (provided by applicant): IPF is a deadly disease characterized by the progressive accumulation of fibroblasts within the alveolar wall and airspace with subsequent deposition of collagen in the airspace. During normal lung repair fibroblasts are eliminated by apoptosis permitting restoration of normal anatomic patterns. In contrast, IPF is characterized by the abnormal persistence of fibroblasts in fibrotic foci where they deposit collagen distorting normal lung architecture resulting in organ dysfunction. Identifying key signaling molecules that regulate lung fibroblast viability in a collagen-rich environment will provide insight into the abnormal persistence of fibroblasts in IPF. We have discovered that a B1 integrin PI-3-kinase/Akt viability pathway regulates lung fibroblast survival in collagen matrices. When fibroblasts attach to collagen via B1 integrin Akt is phosphorylated providing a survival signal. However, in response to collagen matrix contraction, Akt becomes dephosphorylated and fibroblasts undergo apoptosis. Enforced activation of the B1 integrin viability pathway rescues fibroblasts from apoptosis. In this revised proposal we will evaluate the identity of the integrin a subunit(s) associated with B1 integrin to determine which integrin is responsible for regulating Akt activity and fibroblast viability in collagen matrices. Furthermore, novel preliminary data we have developed suggest that the molecular mechanism by which collagen matrix contraction promotes apoptosis is by increases in PTEN phosphatase activity resulting in Akt dephosphorylation. Our studies suggest that the mechanism for the increase in PTEN activity involves SHP1-mediated cytoskeletal disassembly. Importantly, we present novel findings indicating that IPF fibroblasts have a distinct phenotype that is characterized by dysfunction of this integrin viability signaling pathway. These observations lead us to hypothesize that: 1) B1 integrin regulation of lung fibroblast viability through the PI-3-kinase/Akt signaling pathway in collagen matrices involves FAK and ILK which activate Akt and PTEN phosphatase which inhibits Akt activity. 2) In response to collagen contraction, SHPl-mediated cytoskeletal disassembly up-regulates PTEN activity inhibiting the B1 integrin viability pathway. 3) Disease specific alterations in the B1 integrin viability pathway and PTEN activity in IPF fibroblasts underlie their altered survival in collagen matrices. To address our hypotheses we will: Aim 1. Identify the integrin a subunit(s) associated with B1 integrin in regulating the Akt viability signal. Aim 2 Investigate the molecular mechanism by which collagen contraction promotes activation of PTEN, Akt dephosphorylation, and fibroblast apoptosis. Examine the role of PTEN in regulating the B1 integrin/PI-3-kinase/Akt survival signal and fibroblast viability. Aim 3. Explore disease-specific alterations in integrin viability signaling and PTEN activity in IPF fibroblasts in a collagen-rich (fibrotic) microenvironment.

描述（由申请人提供）：IPF是一种致命的疾病，其特征是成纤维细胞在肺泡壁和空腔内逐渐积累，随后胶原蛋白在空腔中沉积。在正常的肺修复过程中，成纤维细胞被细胞凋亡消除，从而恢复正常的解剖模式。相比之下，IPF 的特点是纤维化病灶中成纤维细胞的异常持续存在，它们沉积胶原蛋白，扭曲正常的肺结构，导致器官功能障碍。鉴定在富含胶原蛋白的环境中调节肺成纤维细胞活力的关键信号分子将有助于深入了解 IPF 中成纤维细胞的异常持久性。我们发现 B1 整合素 PI-3 激酶/Akt 活力途径可调节胶原基质中肺成纤维细胞的存活。当成纤维细胞通过 B1 整合素附着到胶原蛋白上时，Akt 会被磷酸化，从而提供生存信号。然而，响应胶原基质收缩，Akt 去磷酸化，成纤维细胞发生凋亡。 B1 整合素活力途径的强制激活可挽救成纤维细胞免于凋亡。在这个修订后的提案中，我们将评估与 B1 整合素相关的整合素 a 亚基的身份，以确定哪个整合素负责调节胶原基质中的 Akt 活性和成纤维细胞活力。此外，我们开发的新的初步数据表明，胶原基质收缩促进细胞凋亡的分子机制是通过 PTEN 磷酸酶活性增加导致 Akt 去磷酸化。我们的研究表明 PTEN 活性增加的机制涉及 SHP1 介导的细胞骨架分解。重要的是，我们提出的新发现表明 IPF 成纤维细胞具有独特的表型，其特征是该整合素活力信号通路功能障碍。这些观察结果使我们推测：1) B1 整合素通过胶原基质中的 PI-3 激酶/Akt 信号通路对肺成纤维细胞活力的调节涉及激活 Akt 的 FAK 和 ILK 以及抑制 Akt 活性的 PTEN 磷酸酶。 2)响应于胶原收缩，SHP1介导的细胞骨架分解上调抑制B1整联蛋白活力途径的PTEN活性。 3) IPF 成纤维细胞中 B1 整合素活力途径和 PTEN 活性的疾病特异性改变是其在胶原基质中存活率改变的基础。为了解决我们的假设，我们将： 目标 1. 鉴定与 B1 整合素相关的整合素 a 亚基在调节 Akt 活力信号中的作用。目标 2 研究胶原收缩促进 PTEN 激活、Akt 去磷酸化和成纤维细胞凋亡的分子机制。检查 PTEN 在调节 B1 整合素/PI-3-激酶/Akt 存活信号和成纤维细胞活力中的作用。目标 3. 探索富含胶原蛋白（纤维化）微环境中 IPF 成纤维细胞中整合素活力信号传导和 PTEN 活性的疾病特异性变化。