Mycoplams Macrophage-activating Lipopeptide-2 Induces THP-1 Cells To Express MMP-9 By MAPKs Pathway

Mononuclear phagocytes were employed to kill the invading pathogens during mycoplasma infection. Transmigration of mononuclear phagocytes across the vascular endothelial and the basal lamina and connective tissue by degrading extracellular matrix. The degradation of the barrier is the premise of transmigration. The matrix metalloproteinases(MMPs), which can degrade the extracellular matrix and participate inflammatory reaction with multiple biological effects,were secreted by neutrophils, mononuclear cells or other lymphocytes.The concentrations of matrix metalloproteinase-9(MMP-9) in the serum of patients or rat amniotic fluid were upregulated by mycoplasma infection, which implying MMP-9 may participate the mycoplasma-induced inflammatory responses. Now the researcher focus on the content of MMP-9 in animal model or patients with mycoplasma infection. This study aim to investigate the mechanisms underlying mycoplasma-induced MMP-9 expression.(1) THP-1 cells were cultured in vitro and were treated by 0.1, 1.0 and 5.0 μg/mL Macrophage-activating lipopeptide-2(MALP-2) for different time,respectively, then the contents of MMP-9 and Tissue inhibitor of metalloproteinase-1(TIMP-1) in the supernatant of cell culture were detected by ELISA and Western blot. The activity of MMP-9 was measured by colorimetry.(2) THP-1 cells were pre-incubated with mitogen-activated protein kinases(MAPKs) inhibitor for 1h, then stimulated with 5μg/mL MALP-2 for 18 h, the contents of MMP-9 were measured by ELISA.Our results showed that the concentrations of MMP-9 and TIMP-1 were very low under normal condition while they were significantly increased at 18 h when treated with 0.1, 1.0 and 5.0μg/mL MALP-2 in a dose dependent manner. The increase of TIMP-1was less than that of MMP-9. The transcription of MMP-9 and TIMP-1were significantly increased at 16 h when treated by different concentrations of MALP-2. The expression of MMP-9 was much more than that of TIMP-1. At the same time, the activity of MMP-9 in the supernatant of cell culture was increased by MALP-2 treatment. Besides,the transcription of MMP-9 in THP-1 cells was up-regulated by MALP-2treatment from 6h to 36 h and achieved its peak at 16 h. The MALP-2-induced MMP-9 expression in THP-1 was significantly inhibited by pretreatment with different chemical inhibitors, SB203580(p38 inhibitor), SP600125(JNK inhibitor) or PD98059(ERK inhibitor).Taken together, our current study demonstrates that mycoplasma MALP-2 can induce the expression of MMP-9 in THP-1 cell through MAPKs pathway.