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Regulation of matrix metalloproteinase-9 (MMP-9) in TNF-stimulated neutrophils: novel pathways for tertiary granule release

2005; Oxford University Press; Volume: 79; Issue: 1 Linguagem: Inglês

10.1189/jlb.0605353

1938-3673

Subhadeep Chakrabarti, Jennifer M. Zee, Kamala D. Patel,

Signaling Pathways in Disease

Abstract Matrix metalloproteinase-9 (MMP-9) is present in the tertiary granules of neutrophils and is rapidly released following stimulation. We examined the pathways that regulate tumor necrosis factor (TNF)-mediated MMP-9 release and found this to be dependent on the TNF receptor I. TNF rapidly activated extracellular signal-regulated kinase and p38 mitogen-activated protein kinases, but neither of these pathways was critical for MMP-9 release. Many neutrophil responses to TNF require β2-integrin-dependent signaling and subsequent Src family kinase activation. In conrast, we found that MMP-9 release from tertiary granules was only partially affected by blocking β2-integrin-mediated adhesion. Similarly, blocking Src family kinases with the inhibitor PP2 only attenuated TNF-induced MMP-9 release. Blocking β2-integrin-mediated adhesion and Src family kinases did not result in additive inhibition of MMP-9 release. In contrast, inhibiting protein kinase C (PKC) with a pan-specific inhibitor blocked greater than 85% of MMP-9 release. Inhibitors against specific PKC isoforms suggested a role for PKC α and PKC δ in maximal MMP-9 release. These data suggest that MMP-9 release from tertiary granules uses β2-integrin-independent signaling pathways. Furthermore, PKC isoforms play a critical role in regulating tertiary granule release.