Mast cell MMP-9 production enhanced by bacterial lipopolysaccharide

Although mast cells contribute to host protective immunity against bacterial infections, the exact mechanism of their recruitment at the affected site has been unclear. Recently, we have reported that both mouse and human mast cells are capable of producing matrix metalloproteinase (MMP)-9, a matrix- degrading enzyme necessary for leukocyte transmigration. Here, we demonstrated that bacterial lipopolysaccharide (LPS) enhanced MMP-9 production of mouse bone marrow derived-cultured mast cells. This action of LPS was partially suppressed by the pretreatment of cultured mast cells with a protein kinase C (PKC) inhibitor, indicating the possible involvement of PKC signaling pathways in the production of MMP-9 by LPS. Thus, these suggest the upregulation of mast cell MMP-9 by bacterial components, thereby resulting in their migration at the affected site.