Quinine oxidoreductase 1 inhibits the secretion of IL-8 in Mycoplasma pneumoniae lipid-associated membrane proteins stimulated the THP-1 monocyte line / 中华微生物学和免疫学杂志

ABSTRACT

Objective:To investigate the effects and regulation mechanism of lipid-associated membrane proteins (LAMPs) derived from Mycoplasma pneumoniae( Mp) on the expression of quinine oxidoreductase 1 (NQO-1) in human monocyte cell line THP-1 cells, and to know the effect of NQO-1 to interleukin 8 secretion in LAMPs stimulated cells, so as to better understand the regulation mechanism upon Mp infection. Methods:Mp were cultivated and the precipitate was collected to extract LAMPs. The cytotoxicity of LAMPs to THP-1 cells was analyzed by using CCK8 test. THP-1 cells were cultured in vitro with different concentrations of LAMPs for different times, and the expression of NQO-1 protein was detected by Western blot. Nrf2 siRNA was used to investigate the role of Nrf2 in NQO-1 expression in LAMPs induced cells, and NQO-1 inhibitor Diminutol was performed to test whether they blocked interleukin 8 (IL-8) secretion when treated with LAMPs in THP-1 cells. Results:LAMPs extracted from Mp had no cytotoxicity to THP-1 cells. The expression of NQO-1 protein in LAMPs-stimulated THP-1 cells showed a dose-dependent and time-dependent manner. The production of NQO-1 protein reached peaks when treated with 5.0 μg/ml or 7.5 μg/ml of LAMPs for 12 h. Silencing of Nrf2 by siRNA significantly decreased NQO-1 production, and blocking NQO-1 by Dim increased the level of IL-8 in LAMPs-stimulated cells. Conclusions:LAMPs derived from Mp induced the expression of NQO-1 protein in THP-1 cells via Nrf2, and NQO-1 can inhibit IL-8 secretion in LAMPs stimulated monocytes.