Crosstalk Between Pleural Mesothelial Cell And Lung Fibroblast Contributes To Pulmonary Fibrosis And The Underlying Mechanisms

Objectives: To explore the interaction between pleural mesothelial cells(PMCs) and lung fibroblasts as well as their roles in pulmonary fibrosis.We hope to provide a new target for clinical diagnosis and treatment in patients with pulmonary fibrosis.Methods: 1.Immunofluorescence staining of lung tissue was used to observe the distributions of PMCs in bleomycin-induced mouse pulmonary fibrosis.The aim was to provide preliminary clues and judgments for PMCs participating in the occurrence of IPF.2.Lung fibroblasts were treated with conditioned medium of PMCs,then CCK-8 was used to detect cell proliferation,and Western blot was used to detect changes of collagen-? and proteins concerned cell differentiation in fibroblasts.The aim was to investigate whether PMCs induced fibrogenic changes in lung fibroblasts.3.PMCs were treated with conditioned medium of lung fibroblasts,then Western blot was used to detect changes of collagen-? and biomarkers of mesothelial-mesenchymal transition(MMT).The aim was to investigate whether lung fibroblasts induced fibrogenic changes in PMCs.4.Levels of TGF-?1,Wnt-5a or CD147 in the conditioned medium of PMCs or lung fibroblasts were detected by ELISA kit,repectively.The aim was to study the secretion of these fibrogenic factors produced by PMCs and lung fibroblasts.5.Inhibitors or neutralizing antibodies were used to block TGF-?1,Wnt or CD147 signals in conditioned medium.The aim was to investigate whether PMCs and lung fibroblasts had pro-fibrotic interactions through the above paracrine factors.6.To investigate the role of TGF-?1,Wnt or CD147 signals in bleomycin-induced mouse pulmonary fibrosis model,neutralizing antibodies or antagonistic peptides were administrated in mice.The aim was to investigate whether blocking paracrine factors could inhibit fibrosis in vivo.Results: 1.In bleomycin-induced mouse pulmonary fibrosis model,PMCs migrated into the lung and co-localized with lung fibroblasts at sub-pleural area of the lung.2.The conditioned medium of PMCs induced differentiation,and collagen-? synthesis in lung fibroblasts.3.The conditioned medium of lung fibroblasts induced MMT and collagen-? synthesis in PMCs.4.PMCs interacted with lung fibroblasts by paracrine of TGF-?1 or Wnts,which induced fibrotic process.5.Blocking extracellular TGF-?1 or Wnt signaling in animal models alleviated bleomycin-induced lung fibrosis in mice.6.CD147 secreted by PMCs induced activation and collagen-? synthesis in lung fibroblasts.Extracellular blocking of CD147 reduced bleomycin-induced mouse pulmonary fibrosis in vivo.Conclusion: PMCs migrated into the lung and interacted with lung fibroblasts,which contributed to the pathogenesis of pulmonary fibrosis.Paracrine of TGF-?1 and Wnts by PMCs and lung fibroblasts,and secretion of CD147 from PMCs played roles in the interaction.Blocking TGF-?1,Wnt or CD147 signal in vivo had an inhibitory effect on pulmonary fibrosis induced by bleomycin.