title: Selective early production of CCL20, or macrophage inflammatory protein 3alpha, by human mast cells in response to Pseudomonas aeruginosa.
abstract: Mast cells are important as sentinel cells in host defense against bacterial infection. Much of their effectiveness depends upon recruiting other immune cells; however, little is known about the mechanisms of this response. CCL20, also known as macrophage inflammatory protein-3alpha (MIP-3alpha), Exodus, and LARC, is a chemokine known to be a potent chemoattractant for immature dendritic cells and T cells. In this study, we examined the human mast cell production of both CCL20 and granulocyte-macrophage colony-stimulating factor (GM-CSF), a critical cytokine for innate immune responses in the lung, in response to Pseudomonas aeruginosa. Reverse transcription-PCR and Western blot analysis demonstrated that the human mast cells (HMC-1) express CCL20 mRNA and are able to produce a significant amount (32.4 ng/ml) of CCL20 protein following stimulation by calcium ionophore and phorbol myristate acetate. Importantly, P. aeruginosa potently stimulated CCL20 production in human cord blood-derived mast cells (CBMC), with production peaking at 6 h after stimulation. This time course of expression was distinct from that of GM-CSF, which peaked after 24 to 48 h. Significant CCL20 production did not occur following immunoglobulin E-mediated activation of CBMC under conditions which induced a substantial GM-CSF response. Interestingly, the CCL20 response of mast cells to P. aeruginosa was relatively resistant to inhibition by the corticosteroid dexamethasone, interleukin-10, or cyclosporine, while GM-CSF production was potently inhibited. However, P. aeruginosa-induced CCL20 production was blocked by the protein kinase C (PKC) inhibitor Ro 31-8220 and a PKC pseudosubstrate. These results support a role for human mast cells in the initiation of immune responses to P. aeruginosa infection.
authors.affiliation: Department of Microbiology & Immunology, Dalhousie University, Halifax, Nova Scotia, B3H 4H7 Canada.
authors.forename: Tong-Jun
authors.initials: TJ
authors.lastname: Lin
authors.forename: Lauren H
authors.initials: LH
authors.lastname: Maher
authors.forename: Kaede
authors.initials: K
authors.lastname: Gomi
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: McCurdy
authors.forename: Rafael
authors.initials: R
authors.lastname: Garduno
authors.forename: Jean S
authors.initials: JS
authors.lastname: Marshall
mesh_terms: D002460:Cell Line; D002478:Cells, Cultured; D054418:Chemokine CCL20; D019742:Chemokines, CC / Q000378:metabolism*; D016572:Cyclosporine / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D005312:Fetal Blood / Q000166:cytology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism; D006801:Humans; D016753:Interleukin-10 / Q000494:pharmacology; D019402:Macrophage Inflammatory Proteins / Q000378:metabolism*; D008407:Mast Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000276:immunology*; D054399:Receptors, CCR6; D019707:Receptors, Chemokine
chemical_list: C108355:CCL20 protein, human; C106311:CCR6 protein, human; D054418:Chemokine CCL20; D019742:Chemokines, CC; D019402:Macrophage Inflammatory Proteins; D054399:Receptors, CCR6; D019707:Receptors, Chemokine; D016753:Interleukin-10; D003907:Dexamethasone; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D016572:Cyclosporine; D011493:Protein Kinase C