Cell type-specific release of matrix-metallo-proteinase-9 by bacterial chemoattractant in human blood phagocytic leukocytes.

Stimulation of phagocytic leukocytes with bacterial chemoattractant resulted in the release of matrix metal-loproteinases (MMPs). Little is known about the mechanisms of bacterial chemoattractant regulation of MMP in phagocytic leukocytes. We report here that the mechanisms of the bacterial chemotactic peptidefMLP-induced MMP -9 release in monocytes appeared to be different from fMLP-stimulated MMP-9 release in neutrophils. In freshly prepared peripheral blood monocytes, fMLP induces MMP-9 release, starting at 8 h after stimulation. These functions of fMLP is accompanied by an increase in TNFα expression, and mediated through the phosphorylation of ERK1/2 in monocytes. However, neutrophil preparations that responded to fMLP with MMP-9 release did not require activation of ERK1/2 and TNFα expression. These results suggest a different role of fMLP in MMP-9 expression in neutrophils and monocytes, and the signal molecules involved in mediating this effect in human blood monocytes stimulated by bacterial chemoattractant.