Objective::Pseudomonas aeruginosa (n P. aeruginosa) contains a hierarchy of quorum sensing (QS) network, consisting of the n las, rhl and n pqs systems, which play a key role in coordinating the expression of virulence factors. n PA2146 was found to be associated with n P. aeruginosa pathogenicity in macrophage and host Immune response. The aim of this study was to investigate the effects of n PA2146 on the virulence of n P. aeruginosa and explore its mechanism.n Methods::PA2146 gene knockout strain and complement strain of n P. aeruginosa PAO1 were constructed. The biomass of biofilm was detected by crystal violet staining; the virulence factors were measured, including pyocyanin, rhamnolipid, LasA elastase, LasB elastase and hemolytic activity; RNA-seq and label-free relative quantitative proteomics analyses were carried out to test the influence of n PA2146 on transcriptomics and proteomics. This study was approved by the Institutional Review Board of the Third Xiangya Hospital, Central South University, China (approval No. 2019-S021).n Results::PA2146-deficient strains showed reduced biofilm formation and increased pyocyanin, rhamnolipid, LasA elastase, LasB elastase, and hemolytic activity, as well as increased motility, compared with the wild-type strain. RNA-seq and label-free relative quantitative proteomics analyses revealed that n PA2146 repressed the transcription of several genes that are integral to the n pqs system and to pyocyanin biosynthesis, and increased the expression of MexEF-OprN efflux pump components at the gene and protein level.n Conclusion::PA2146 gene was found to inhibit the n pqs system. n PA2146 may affect quorum sensing by directly inhibiting the n pqs system or by enhancing the expression of MexEF-OprN efflux pump components, thereby promoting efflux of 2-heptyl-4(1H)-quinolone, a n Pseudomonas quinolone signal precursor, and thus affecting n P. aeruginosa virulence.n “,”Objective::Pseudomonas aeruginosa (n P. aeruginosa) contains a hierarchy of quorum sensing (QS) network, consisting of the n las, rhl and n pqs systems, which play a key role in coordinating the expression of virulence factors. n PA2146 was found to be associated with n P. aeruginosa pathogenicity in macrophage and host Immune response. The aim of this study was to investigate the effects of n PA2146 on the virulence of n P. aeruginosa and explore its mechanism.n Methods::PA2146 gene knockout strain and complement strain of n P. aeruginosa PAO1 were constructed. The biomass of biofilm was detected by crystal violet staining; the virulence factors were measured, including pyocyanin, rhamnolipid, LasA elastase, LasB elastase and hemolytic activity; RNA-seq and label-free relative quantitative proteomics analyses were carried out to test the influence of n PA2146 on transcriptomics and proteomics. This study was approved by the Institutional Review Board of the Third Xiangya Hospital, Central South University, China (approval No. 2019-S021).n Results::PA2146-deficient strains showed reduced biofilm formation and increased pyocyanin, rhamnolipid, LasA elastase, LasB elastase, and hemolytic activity, as well as increased motility, compared with the wild-type strain. RNA-seq and label-free relative quantitative proteomics analyses revealed that n PA2146 repressed the transcription of several genes that are integral to the n pqs system and to pyocyanin biosynthesis, and increased the expression of MexEF-OprN efflux pump components at the gene and protein level.n Conclusion::PA2146 gene was found to inhibit the n pqs system. n PA2146 may affect quorum sensing by directly inhibiting the n pqs system or by enhancing the expression of MexEF-OprN efflux pump components, thereby promoting efflux of 2-heptyl-4(1H)-quinolone, a n Pseudomonas quinolone signal precursor, and thus affecting n P. aeruginosa virulence.n