Macrophage-activating lipopeptide-2 induces the expression of hemeoxygenase-1 in THP-1 cells and its possible mechanism
10.3760/cma.j.issn.0254-5101.2014.06.010
- VernacularTitle:支原体巨噬细胞活化脂肽2诱导单核细胞系THP-1表达血红素氧合酶1及其机制研究
- Author:
Xiaoxing YOU
;
Xiaohua MA
;
Liangzhuan LIU
;
Yanhua ZENG
;
Minjun YU
;
Cuiming ZHU
;
Jun HE
;
Chuanhao JIANG
;
Yimou WU
- Publication Type:Journal Article
- Keywords:
Macrophage-activating lipopeptide-2;
Hemoxygenase-1;
Monocyte
- From:
Chinese Journal of Microbiology and Immunology
2014;(6):453-458
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate whether macrophage-activating lipopeptide-2 ( MALP-2) in-duces the expression of hemoxygenase-1 ( HO-1 ) in THP-1 cells and to further elucidate its possible regulatory mechanism for a better understanding of protective response upon mycoplasma infection .Methods THP-1 cells were cultured in vitro and stimulated by MALP-2 at different concentrations for 12 h.THP-1 cells were incubated with TLR 2 or TLR6 neutralizing antibodies , or transfected with their dominant negative plasmids to evaluate the effects of TLR 2 and TLR6 on HO-1 expression .Phosphorylation of Akt was detected by Western blot.PI3K inhibitor LY294002 was used to investigate the role of PI3K in HO-1 expression.Im-munofluorescence and electrophoretic mobility shift assay ( EMSA ) were performed to observe the nuclear translocation and DNA-binding activity of nuclear factor Nrf 2.Small interfering RNA ( siRNA) was used to silence the genes encoding Nrf2 and HO-1.Cobalt protoporphyrin (CoPP), an inducer of HO-1, was used to treat THP-1 cells.The expression of HO-1 was detected by Western blot .The secretion of TNF-αand IL-1βby THP-1 cells were measured by ELISA .Results MALP-2 induced the expression of HO-1 in THP-1 cells.However, the expression of HO-1 was inhibited by TLR2 and TLR6 neutralizing antibodies and expres-sion of their dominant negative plasmids .Moreover, PI3K pathway was activated by MALP-2, and with the use of PI3K inhibitor, the expression of HO-1 was decreased.The translocation of Nrf2 to the nucleus and itsDNA-binding activity were enhanced by MALP-2, but were inhibited by the treatment of PI3K inhibitor.Theexpression of HO-1 was significantly down-regulated upon the interference of Nrf2 gene expression withsiRNA.Silenced expression of HO-1 increased the level of TNF-αand IL-1β, while CoPP treatment decreasedthe secretion of MALP-2-induced cytokines.Conclusion MALP-2 might induce the expression ofHO-1 in THP-1 cells through TLR2,6/PI3K/Nrf2 pathways.The expression of HO-1 could negatively regulatethe hyper-secretion of cytokines.
