Objective::In order to study the important role and molecular mechanism of Brevinin-2 family antimicrobial peptide Brevinin-2ISb in methicillin-resistant Staphylococcus aureus(MRSA)infection of Caenorhabditis(C.)elega...Objective::In order to study the important role and molecular mechanism of Brevinin-2 family antimicrobial peptide Brevinin-2ISb in methicillin-resistant Staphylococcus aureus(MRSA)infection of Caenorhabditis(C.)elegans,and to find the optimal therapeutic concentration of Brevinin-2ISb.Methods::By using a C.elegans model and MRSA infection modelto study the therapeutic effect of different concentrations of Brevinin-2ISb on C.elegans.Real-time PCR was used for investigating the effect of Brevinin-2ISb on the downstream gene expression of DAF-2/DAF-16 innate immune pathway and the major virulence factor gene expression of MRSA.With protein activity tests to study the inhibitory effect of Brevinin-2ISb on MRSA virulence factor protein activity.Finally,laser confocal imaging was carried out to observe real-time expression and distribution of downstream antimicrobial proteins to further prove the effect of Brevinin-2ISb on the activation of DAF-2/DAF-16 pathway by in vivo imaging.All animal study procedures were approved by the Academic Committee at Xidian University and Xi’an Jiaotong University Animal Care and Use Committee,China(approval No.JGC201207)on July 15,2017.Results::Host immunity was largely enhanced by Brevinin-2ISb,and the expression of staphylococcal enterotoxin genes,as well as virulence factors,was suppressed by Brevinin-2ISb.Indeed,the expression of many C.elegans innate immune genes,including lys-7,spp-1,K05D8.5 and C29F3.7,was induced by Brevinin-2ISb.In particular,robust,sustained expression of the antibacterial gene lys-7 was observed after Brevinin-2ISb treatment,resulting in increased protein levels.These effects correlated with a reduction in the MRSA-mediated death of the C.elegans host.Low concentrations of Brevinin-2ISb exhibited very low hemolytic activity,and may play a positive role in host innate immunity.Specifically,activation of the DAF-2/DAF-16 pathway appears to be essential for immune activation in C.elegans treated with Brevinin-2ISb.Based on the evolutionary conservation of innate immune pathways,our results suggest that Brevinin-2ISb not only has strong antibacterial activity,but may also enhance the innate immune response in humans.This study demonstrates that Brevinin-2ISb-related peptides are potential candidates for the development of novel anti-inflammatory or anti-microbial drugs.Conclusion::Antimicrobial peptide Brevinin-2ISb effectively inhibits MRSA at low concentration.This antimicrobial peptide can prolong the life of MRSA-infected C.elegans,has very low hemolytic activity and inhibits the activity and expression of various MRSA virulence factors.More importantly,Brevinin-2ISb activated the expression of antimicrobial genes downstream of DAF-2/DAF-16,which enhanced the MRSA resistance of C.elegans.This peptide could be used as the basis for developing new drugs to replace antibiotics.展开更多
基金supported in part by the National Key R&D Program of China(No.2018YFC0910600)the National Natural Science Foundation of China(Nos.62007026,81627807,11727813,81871397,81701853,91859109)+3 种基金the Fok Ying-Tong Education Foundation of China(No.161104)the Program for the Young Top-notch Talent of Shaanxi Province,the Research Fund for Young Star of Science and Technology in Shaanxi Province of China(No.2018KJXX-018)the Science and Technology Projects of Xi’an,China(No.201809170CX11JC12)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2019JQ-201).
文摘Objective::In order to study the important role and molecular mechanism of Brevinin-2 family antimicrobial peptide Brevinin-2ISb in methicillin-resistant Staphylococcus aureus(MRSA)infection of Caenorhabditis(C.)elegans,and to find the optimal therapeutic concentration of Brevinin-2ISb.Methods::By using a C.elegans model and MRSA infection modelto study the therapeutic effect of different concentrations of Brevinin-2ISb on C.elegans.Real-time PCR was used for investigating the effect of Brevinin-2ISb on the downstream gene expression of DAF-2/DAF-16 innate immune pathway and the major virulence factor gene expression of MRSA.With protein activity tests to study the inhibitory effect of Brevinin-2ISb on MRSA virulence factor protein activity.Finally,laser confocal imaging was carried out to observe real-time expression and distribution of downstream antimicrobial proteins to further prove the effect of Brevinin-2ISb on the activation of DAF-2/DAF-16 pathway by in vivo imaging.All animal study procedures were approved by the Academic Committee at Xidian University and Xi’an Jiaotong University Animal Care and Use Committee,China(approval No.JGC201207)on July 15,2017.Results::Host immunity was largely enhanced by Brevinin-2ISb,and the expression of staphylococcal enterotoxin genes,as well as virulence factors,was suppressed by Brevinin-2ISb.Indeed,the expression of many C.elegans innate immune genes,including lys-7,spp-1,K05D8.5 and C29F3.7,was induced by Brevinin-2ISb.In particular,robust,sustained expression of the antibacterial gene lys-7 was observed after Brevinin-2ISb treatment,resulting in increased protein levels.These effects correlated with a reduction in the MRSA-mediated death of the C.elegans host.Low concentrations of Brevinin-2ISb exhibited very low hemolytic activity,and may play a positive role in host innate immunity.Specifically,activation of the DAF-2/DAF-16 pathway appears to be essential for immune activation in C.elegans treated with Brevinin-2ISb.Based on the evolutionary conservation of innate immune pathways,our results suggest that Brevinin-2ISb not only has strong antibacterial activity,but may also enhance the innate immune response in humans.This study demonstrates that Brevinin-2ISb-related peptides are potential candidates for the development of novel anti-inflammatory or anti-microbial drugs.Conclusion::Antimicrobial peptide Brevinin-2ISb effectively inhibits MRSA at low concentration.This antimicrobial peptide can prolong the life of MRSA-infected C.elegans,has very low hemolytic activity and inhibits the activity and expression of various MRSA virulence factors.More importantly,Brevinin-2ISb activated the expression of antimicrobial genes downstream of DAF-2/DAF-16,which enhanced the MRSA resistance of C.elegans.This peptide could be used as the basis for developing new drugs to replace antibiotics.
