title: Antisense locked nucleic acids targeting agrA inhibit quorum sensing and pathogenesis of community-associated methicillin-resistant Staphylococcus aureus.
abstract: OBJECTIVE
  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)3K peptide-conjugated locked nucleic acids (PLNAs) targeting agrA mRNA were developed to inhibit agr activity and arrest the pathogenicity of CA-MRSA.
  
  
  RESULTS
  Two PLNAs 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 PLNAs on inhibiting agr QS. A mouse skin infection model was employed to test the protective effect of the PLNAs in vivo. None of the PLNAs were found to be bacteriostatic or bactericidal in vitro. However, one PLNA, PLNA34, showed strong ability to suppress expression of agrA and the effector molecule RNAIII in USA300 LAC strain. Furthermore, PLNA34 inhibited the expression of virulence genes that are upregulated by agr, including hla, psmα, psmβ and pvl. The haemolytic activity of the supernatants from PLNA34-treated bacteria was also dramatically reduced, as well as the capacity to lyse and recruit neutrophils. Moreover, PLNA34 showed high levels of protection in the CA-MRSA mouse skin infection model.
  
  
  CONCLUSIONS
  The anti-agrA PLNA34 can effectively inhibit the agr QS and suppress CA-MRSA pathogenicity.
  
  
  CONCLUSIONS
  agrA is a promising target for the development of antisense oligonucleotides to block agr QS.
authors.affiliation: Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China.
authors.forename: F
authors.initials: F
authors.lastname: Da
authors.affiliation: Department of Medicinal Chemistry, School of Pharmacy, Fourth Military Medical University, Xi'an, China.
authors.forename: L
authors.initials: L
authors.lastname: Yao
authors.affiliation: Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Su
authors.affiliation: Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Hou
authors.affiliation: Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China.
authors.forename: X
authors.initials: X
authors.lastname: Xue
authors.affiliation: Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China.
authors.forename: J
authors.initials: J
authors.lastname: Meng
authors.affiliation: Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China.
authors.forename: X
authors.initials: X
authors.lastname: Luo
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D017714:Community-Acquired Infections / Q000382:microbiology* / Q000628:therapy; D016373:DNA, Antisense / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity* / Q000502:physiology; D051379:Mice; D009841:Oligonucleotides / Q000235:genetics* / Q000378:metabolism; D053038:Quorum Sensing; D013203:Staphylococcal Infections / Q000382:microbiology* / Q000628:therapy; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D016373:DNA, Antisense; D009841:Oligonucleotides; C477371:locked nucleic acid
keywords: 
  agr
  ; antisense; locked nucleic acid; methicillin-resistant Staphylococcus aureus; skin infection; virulence