The effect of small interfering RNA against Pseudomonas aeruginosa expressing MexA-MexB-OprM efflux pumps in vivo / 中华微生物学和免疫学杂志

Objective To investigate the efficacy of small interfering RNA against Pseudomonos aeruginosa expressing MexA-MexB-OprM multidrug efflux pump in vivo.Methods Two short hairpin (sh)RNA expression vectors targeting the MexB gene,and negative controls,were designed,synthesized,and electrotransformed into the P.aeruginosa strain PAO1.The in vivo therapeutic efficacy of the MexB small interfering (si)RNAs was determined by infecting a murine model of chronic P.aeruginosa lung infection (1 × 107 CFU/ml).The mice were killed on day 3,5 and 7 after infection with the Pseudomonas aeruginosa strains.Results In the murine infection model,treatment with MexB-siRNAs led to significantly reduced bacteria burden of the bellows by day 5 and 7 post-infection,and reduced the P.aeruginosa-induced pathological changes.In addition,MexB-siRNA2 treatment enhanced neutrophil recruitment and production of inflammatory cytokines (IL-1β,IL-12) in the early infection stage (day 3) (P＜0.05),both of which decreased by day 7.Conclusion MexB-siRNA could inhibit both mRNA expression and the activity of P.aeruginosa in vitro.siRNA was effective in reducing the bacterial load in a murine model of chronic lung infection.Targeting of MexB with siRNA appears to be a novel strategy for treating P.aeruginosa infections.

The effect on MexB expression with siRNA silencing mexB gene of Pseudomonas aeruginosa / 中华微生物学和免疫学杂志

ObjectiveTo investigate the alteration of MexB protein expression by plasmid containing siRNA template strand was transformed into Pseudomonas aeruginosa.Methods siRNA molecules specifically against mexB were designed and ligated into pGPU6/GFP/Neo vector to construct the recombinant plasmid pGPU6/GFP/Neo-siRNA.MexB gene was cloned into expression vector pET22b+ to construct plasmid pET22b+/mexB,the recombinant expression plasmid was transformed into E.coli BL21 (DE3)plysS and protein MexB was induced to express,then purified protein MexB was used to prepare specific antibodies in rabbits.The plasmids with siRNA molecules specifically against mexB were transformed into wild type strain,clinical multiresistant strain and mexB overexpression strain of Pseudomonas aeruginosa by electroporation respectively,and the changes of the expression of MexB were detected in 8,12,24 h respectively by Western blot.ResultspGPU6/GFP/Neo-siRNA was constructed successfully.Protein MexB was expressed successfully and the rabbit polyclonal antibodies against MexB was prepared well.The gene silence of mexB by siRNA molecules was effective in the three strains of Pseudomonas aeruginosa,but it depended on the silencing time.ConclusionThe expression of MexB was reduced in 8 h and 12 h,but in 24 h,the expression was unchanged.