title: Regulation of matrix metalloproteinase-9 release from IL-8-stimulated human neutrophils.
abstract: Matrix metalloproteinase-9 (MMP-9) is present in the tertiary granules of neutrophils and can be released following stimulation. We examined the signaling mechanisms that regulate interleukin-8 (IL-8)-mediated MMP-9 release from neutrophils. IL-8 activates neutrophils by interacting with two receptors: CXC chemokine receptor 1 (CXCR1) and CXCR2. Blocking CXCR1 had no effect on IL-8-mediated MMP-9 release, whereas blocking CXCR2 significantly reduced MMP-9 release. We also found that stimulating CXCR2 alone was sufficient to induce MMP-9 release. This process was independent of changes in the intracellular calcium concentration. Src-family kinases and protein kinase C (PKC) were involved in two mutually exclusive pathways regulating IL-8-mediated MMP-9 release. Inhibition of extracellular signal-regulated kinase (ERK)1/2 blocked IL-8-mediated MMP-9 release; however, inhibition of p38 mitogen-activated protein kinase had no effect on MMP-9 release. We found ERK1/2 was activated downstream of PKC, but not Src-family kinases, in this system. These data suggest that IL-8-induced MMP-9 release from neutrophils is mediated through CXCR2 and involves two distinct pathways, one involving PKC and ERK1/2 and the other involving Src-family kinases. Furthermore, our data show that the mechanisms that regulate MMP-9 release from tertiary granules are different from those that regulate primary granule release.
authors.affiliation: Department of Physiology and Biophysics, Immunology Research Group, University of Calgary, Alberta, Canada.
authors.forename: Subhadeep
authors.initials: S
authors.lastname: Chakrabarti
authors.forename: Kamala D
authors.initials: KD
authors.lastname: Patel
mesh_terms: D002118:Calcium / Q000378:metabolism; D006801:Humans; D016209:Interleukin-8 / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000276:immunology*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009504:Neutrophils / Q000187:drug effects* / Q000201:enzymology* / Q000276:immunology; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D023062:Receptors, Interleukin-8A / Q000378:metabolism; D023063:Receptors, Interleukin-8B / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D016209:Interleukin-8; D023062:Receptors, Interleukin-8A; D023063:Receptors, Interleukin-8B; D019061:src-Family Kinases; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020780:Matrix Metalloproteinase 9; D002118:Calcium