title: Plasminogen-stimulated inflammatory cytokine production by airway smooth muscle cells is regulated by annexin A2.
abstract: Plasminogen has a role in airway inflammation. Airway smooth muscle (ASM) cells cleave plasminogen into plasmin, a protease with proinflammatory activity. In this study, the effect of plasminogen on cytokine production by human ASM cells was investigated in vitro. Levels of IL-6 and IL-8 in the medium of ASM cells were increased by incubation with plasminogen (5-50 μg/ml) for 24 hours (P < 0.05; n = 6-9), corresponding to changes in the levels of cytokine mRNA at 4 hours. The effects of plasminogen were attenuated by α2-antiplasmin (1 μg/ml), a plasmin inhibitor (P < 0.05; n = 6-12). Exogenous plasmin (5-15 mU/ml) also stimulated cytokine production (P < 0.05; n = 6-8) in a manner sensitive to serine-protease inhibition by aprotinin (10 KIU/ml). Plasminogen-stimulated cytokine production was increased in cells pretreated with basic fibroblast growth factor (300 pM) in a manner associated with increases in urokinase plasminogen activator expression and plasmin formation. The knockdown of annexin A2, a component of the putative plasminogen receptor comprised of annexin A2 and S100A10, attenuated plasminogen conversion into plasmin and plasmin-stimulated cytokine production by ASM cells. Moreover, a role for annexin A2 in airway inflammation was demonstrated in annexin A2-/- mice in which antigen-induced increases in inflammatory cell number and IL-6 levels in the bronchoalveolar lavage fluid were reduced (P < 0.01; n = 10-14). In conclusion, plasminogen stimulates ASM cytokine production in a manner regulated by annexin A2. Our study shows for the first time that targeting annexin A2-mediated signaling may provide a novel therapeutic approach to the treatment of airway inflammation in diseases such as chronic asthma.
authors.affiliation: 1 Department Pharmacol, University of Melbourne, Parkville, Victoria, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Schuliga
authors.forename: Shenna
authors.initials: S
authors.lastname: Langenbach
authors.forename: Yuxiu C
authors.initials: YC
authors.lastname: Xia
authors.forename: Chengxue
authors.initials: C
authors.lastname: Qin
authors.forename: Josephine S L
authors.initials: JS
authors.lastname: Mok
authors.forename: Trudi
authors.initials: T
authors.lastname: Harris
authors.forename: Graham A
authors.initials: GA
authors.lastname: Mackay
authors.forename: Robert L
authors.initials: RL
authors.lastname: Medcalf
authors.forename: Alastair G
authors.initials: AG
authors.lastname: Stewart
mesh_terms: D000818:Animals; D017306:Annexin A2 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D002478:Cells, Cultured; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D004195:Disease Models, Animal; D005341:Fibrinolysin / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism*; D015850:Interleukin-6 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009130:Muscle, Smooth / Q000276:immunology / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000276:immunology / Q000378:metabolism*; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism; D010958:Plasminogen / Q000378:metabolism*; D011014:Pneumonia / Q000276:immunology / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012137:Respiratory System / Q000276:immunology / Q000378:metabolism*; D015398:Signal Transduction; D013997:Time Factors; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism; D000979:alpha-2-Antiplasmin / Q000378:metabolism
chemical_list: C472822:ANXA2 protein, human; D017306:Annexin A2; C508606:CXCL8 protein, human; D016207:Cytokines; C508600:IL6 protein, human; D018836:Inflammation Mediators; D015850:Interleukin-6; D016209:Interleukin-8; D012333:RNA, Messenger; D000979:alpha-2-Antiplasmin; D016222:Fibroblast Growth Factor 2; D010958:Plasminogen; D058539:Phosphatidylinositol 3-Kinase; D051057:Proto-Oncogene Proteins c-akt; D020928:Mitogen-Activated Protein Kinases; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator