title: VEGF secretion during hypoxia depends on free radicals-induced Fyn kinase activity in mast cells.
abstract: Mast cells (MC) have an important role in pathologic conditions such as asthma and chronic obstructive pulmonary disease (COPD), where hypoxia conduce to deleterious inflammatory response. MC contribute to hypoxia-induced angiogenesis producing factors such as vascular endothelial growth factor (VEGF), but the mechanisms behind the control of hypoxia-induced VEGF secretion in this cell type is poorly understood. We used the hypoxia-mimicking agent cobalt chloride (CoCl2) to analyze VEGF secretion in murine bone marrow-derived mast cells (BMMCs). We found that CoCl2 promotes a sustained production of functional VEGF, able to induce proliferation of endothelial cells in vitro. CoCl2-induced VEGF secretion was independent of calcium rise but dependent on tetanus toxin-sensitive vesicle-associated membrane proteins (VAMPs). VEGF exocytosis required free radicals formation and the activation of Src family kinases. Interestingly, an important deficiency on CoCl2-induced VEGF secretion was observed in Fyn kinase-deficient BMMCs. Moreover, Fyn kinase was activated by CoCl2 in WT cells and this activation was prevented by treatment with antioxidants such as Trolox and N-acetylcysteine. Our results show that BMMCs are able to release VEGF under hypoxic conditions through a tetanus toxin-sensitive mechanism, promoted by free radicals-dependent Fyn kinase activation.
authors.affiliation: Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados del IPN (Cinvestav, IPN), Mexico.
authors.forename: Jonathan
authors.initials: J
authors.lastname: García-Román
authors.forename: Alfredo
authors.initials: A
authors.lastname: Ibarra-Sánchez
authors.forename: Mónica
authors.initials: M
authors.lastname: Lamas
authors.forename: Claudia
authors.initials: C
authors.lastname: González Espinosa
mesh_terms: D000818:Animals; D020126:Brefeldin A / Q000494:pharmacology; D002460:Cell Line; D003035:Cobalt / Q000494:pharmacology; D005609:Free Radicals / Q000378:metabolism*; D000860:Hypoxia / Q000378:metabolism*; D008407:Mast Cells / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008817:Mice, Mutant Strains; D051076:Proto-Oncogene Proteins c-fyn / Q000096:biosynthesis* / Q000235:genetics; D050683:R-SNARE Proteins / Q000378:metabolism; D013744:Tetanus Toxin / Q000494:pharmacology; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
chemical_list: D005609:Free Radicals; D050683:R-SNARE Proteins; D013744:Tetanus Toxin; D042461:Vascular Endothelial Growth Factor A; D020126:Brefeldin A; D003035:Cobalt; D051076:Proto-Oncogene Proteins c-fyn; C018021:cobaltous chloride