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Antisense locked nucleic acids targeting agrA inhibit quorum sensing and pathogenesis of community‐associated methicillin‐resistant Staphylococcus aureus
Author(s) -
Da F.,
Yao L.,
Su Z.,
Hou Z.,
Li Z.,
Xue X.,
Meng J.,
Luo X.
Publication year - 2017
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.13321
Subject(s) - quorum sensing , agra , microbiology and biotechnology , virulence , staphylococcus aureus , biology , effector , methicillin resistant staphylococcus aureus , bacteria , gene , biochemistry , ecology , genetics
Aim Community‐associated methicillin‐resistant Staphylococcus aureus ( CA ‐ MRSA ) is commonly associated with nonnosocomial skin and soft tissue infections due to its virulence, which is mainly controlled by the accessory gene regulator ( agr ) quorum sensing ( QS ) system. In this study ( KFF ) 3 K peptide‐conjugated locked nucleic acids ( PLNA s) targeting agrA mRNA were developed to inhibit agr activity and arrest the pathogenicity of CA ‐ MRSA . Methods and Results Two PLNA s were designed, and synthesized, after predicting the secondary structure of agrA mRNA . The influence on bacterial growth was tested using a growth curve assay. RT ‐ qPCR , haemolysis assay, lactate dehydrogenase release assay and chemotaxis assay were used to evaluate the effects of the PLNA s on inhibiting agr QS . A mouse skin infection model was employed to test the protective effect of the PLNA s in vivo . None of the PLNA s were found to be bacteriostatic or bactericidal in vitro . However, one PLNA , PLNA 34, showed strong ability to suppress expression of agrA and the effector molecule RNAIII in USA 300 LAC strain. Furthermore, PLNA 34 inhibited the expression of virulence genes that are upregulated by agr , including hla , psmα , psmβ and pvl . The haemolytic activity of the supernatants from PLNA 34‐treated bacteria was also dramatically reduced, as well as the capacity to lyse and recruit neutrophils. Moreover, PLNA 34 showed high levels of protection in the CA ‐ MRSA mouse skin infection model. Conclusions The anti‐ agrA PLNA 34 can effectively inhibit the agr QS and suppress CA ‐ MRSA pathogenicity. Significance and Impact of the Study agrA is a promising target for the development of antisense oligonucleotides to block agr QS .