Thrombin於發炎性肋膜積水誘發纖維化過程中第一型胞漿素原活化抑制劑參與調控機轉之研究(2/2)

Project: A - Government Institutionb - Ministry of Science and Technology

Description

Pleural inflammation and pleuropulmonary fibrosis may progress to irreversible thoracic dysfunction with significant morbidity and mortality. Pleural injury activates pleural mesothelial cells (PMCs) to express plasminogen activator inhibitor (PAI)-1 and inhibits fibrinolysis, promotes pleural inflammation and fibrosis. PAI-1 knockdown was reported to ablate bleomycin-induced lung fibrosis by inhibiting epithelial to mesenchymal transition (EMT). Thrombin triggers proteinase-activated receptors (PARs), induces EMT and increases PAI-1 synthesis in endothelial cells, and direct thrombin inhibition attenuates lung fibrosis. All indicate that both PAI-1 and thrombin are essential in inflammation and fibrosis. However, the role of thrombin in pleural inflammation and pleuropulmonary fibrosis and whether PAI-1 is implicated in thrombin-induced fibrogenesis have never been investigated. Our preliminary data demonstrated that thrombin increased PAI-1 expression via PAR-1/JNK/AP-1 signaling, and induced α-SMA expression and collagen synthesis in human PMCs. PAI-1 siRNA repressed thrombin-induced JNK phosphorylation, α-SMA and collagen production in PMCs. Moreover, the pleural levels of thrombin and PAI-1 were significantly elevated and correlated in inflammatory effusions and pleural fibrosis. Central hypothesis is that thrombin induces PMCs to elaborate PAI-1 that mediates fibrogenesis in inflammatory effusions. Specific Aim 1: To explore the thrombin-induced PAI-1 expression, EMT and collagen synthesis in PMCs, the activated receptors and signalings and the implication mechanism of PAI-1 in vitro (1st year). Hypothesis 1: Thrombin induces PAI-1 expression and then activates EMT and collagen synthesis 1.1. To measure the expression of PAI-1, α-SMA and collagen in PMCs induced by thrombin. 1.2. To find the activated thrombin receptors and signalings in thrombin–induced PAI-1 expression 1.3. To study the role of PAI-1 in regulation of thrombin–induced α-SMA and collagen expression Specific Aim 2: To define the clinical implication of thrombin and PAI-1 in patients with inflammatory pleural effusions and pleuropulmonary fibrosis (2nd year). Hypothesis 2: Thrombin and PAI-1 correlate with pleuropulmonary fibrosis and predict outcomes. 2.1. To measure and compare the protein levels and gene expression (mRNA) of thrombin, PAI-1, in pleural fluids among patients with inflammatory pleural effusions and pleuropulmonary fibrosis. 2.2. Link the protein levels and gene expression (mRNA) of thrombin, PAI-1, α-SMA and collagen in pleural fluids with clinical data to find a predictive biomarker. 2.3. To conduct a randomized, double blind, placebo-controlled trial with inhibitors of thrombin or PAI-1 for treatment of inflammatory pleural effusions and pleuropulmonary fibrosis. Specific Aim 3: To define the role of PAI-1 in regulation of thrombin-induced pleural inflammation and pleuropulmonary fibrosis in vivo. (3rd years). Hypothesis 3: PAI-1 mediates thrombin-induced pleuropulmonary fibrosis in vivo. 3.1 To measure the thrombin and PAI-1 levels and pleuropulmonary fibrosis in thrombin gene transfected murine models. 3.2. To examine the effect of PAI-1 siRNA on pleuropulmonary fibrosis in thrombin gene transfected murine models 3.3. To assess EMT and pleuropulmonary fibrosis in the thrombin-treated PAI-1-knockout mice.
StatusFinished
Effective start/end date8/1/177/31/18

Keywords

  • epithelial to mesenchymal transition
  • plasminogen activator inhibitor-1
  • pleural mesothelial cell
  • pleuropulmonary fibrosis
  • thrombin