ABSTRACT
Objective To study the role of TLR2 and TLR4 signal transduction in RAW264.7 monocyte-macrophages stimulated by Aspergillus fumigatus conidia,and to investigate the expression of TLR2 signal transduction after silencing gene of TLR4.Methods Macrophages were randomly divided into normal group ( N group),normal+stimulated with Aspergillus fumigatus conidia ( N +Af group ),normal + transfected with TLR4-siRNA [ TLR4 (RNAi) group ],normal+transfected with TLR4-siRNA +stimulated with Aspergillus fumigatus conidia[ TLR4(RNAi) +Af group].RT-PCR and Western blot were used to assay expression levels of TLR2,TLR4,MyD88 mRNA and pro-inflammatory cytokines TNF-α protein when macrophages were stimulated 12 h by Aspergillus fumigatus conidia after tranfected 24 h with TLR4-siRNA by technology of RNAi.Results ( 1 ) Compared with N group,the expression of TLR2,TLR4,MyD88 mRNA and TNF-αprotein in N+Af group significantly increased before silencing gene of TLR4.(2) Silencing efficiency of macrophates was up to 83％ after transfected with TLR4-siRNA.(3)The expression of TLR2,MyD88 mRNA in TLR4 (RNAi) group significantly decreased contrast with normal group.Meanwhile the expression of TLR2,MyD88 mRNA and TNF-α protein also obviously reduced in TLR4(RNAi) +Af group when compared with N +Af group.Compared with TLR4 (RNAi) group,the expression of MyD88 mRNA in TLR4 (RNAi) +Af group significantly increased.However,the expression of TLR2 mRNA and TNF-α protein have no significant change after silencing gene of TLR4.Conclusion Signaling pathway of TLR2 and TLR4 in macrophages was activated by given stimulus of Aspergillusfumigatus conidia and exerted the effect of anti-Aspergillus fumigatus spores stimulation through the release of pro-inflammatory cytokines TNF-α.Meanwhile,silencing gene of TLR4 down-regulate the effect of TLR2 signal transduction in RAW264.7 cells to anti-Aspergillus fumigatus conidia stimulation,and it found that TLR4 played an more important role by contrast with TLR2.