In vitro and In vivo evaluation of antiendotoxin activity of thepepR peptide against endotoxin mediated shock and invasivePseudomonas aeruginosa Infection

Background and Aim : Sepsis and septic shock are important medical problems with highmortality rates. Common treatment of sepsis is based of antibiotic therapy to target the bacteria,without addressing the systemic inflammatory response, which is a major contributor to mortalityin sepsis. Accordingly, novel treatment options are necessary to counteract these complex sepsispathologies. Here, antiendotoxin activity of the PepR peptide which derived from capside of dengovirus was investigated against P. aeroginosa.Methods : The MIC and MBC values of PepR against P. aeroginosa ATCC ۲۷۸۵۳ was determinedby the microtiter broth dilution method. In vitro and In vivo LPS models were prepared byaffecting PepR on macrophages cells (۳.۵×۱۰۵ cells/well) and Male Balb/c mice (۸–۱۰ weeks),respectively. The levels of IL-۶, IL-۱۰, MCP-۱, IFN-ˠ, and TNF-α were measured in both cellculture supernatants and murine plasma using the Mouse Inflammation Kit according to themanufacturer’s instructions. In addition, P. aeruginosa infection model was prepared by intraperitoneallyinjection of bacterial suspension and subcutaneously injection of PepR in male Balb/cmice. Finally, bacterial dissemination to target organs including spleen, liver and kidney wasdetermined by measuring cfu/g. Results:Results : MIC and MBC of PepR for ATCC ۲۷۸۵۳ P. aeruginosa strains were ۸ and ۱۶ μg/mL,respectively. The results showed that PepR has antimicrobial activity against the P. aeruginosastrain. Moreover, PepR binds to LPS and thereby decrease LPS-induced pro-inflammatoryresponses by reducing in vitro NF-kB/AP-۱ activation. In mouse models of LPS-induced shock,PepR significantly increased survival by modulating the pro-inflammatory cytokine response.Finally, in an invasive Pseudomonas infection model, the peptide inhibited bacterial growth andreduced the pro-inflammatory response, resulting in a significant reduction of mortality.Conclusion : Given simultaneously targeting bacteria and LPS-induced pro-inflammatoryresponses by PepR, the peptide could be considered as a novel promising therapeutic candidate forinvasive infections.

کلیدواژه ها:

Antimicrobial peptides ، PepR ، Pseudomonas aeruginosa ، Anti-endotoxin ، Antiinflammatory ، LPS.