NLF20: an antimicrobial peptide with therapeutic potential against invasive Pseudomonas aeruginosa infection.
OBJECTIVE
Increasing resistance to antibiotics makes antimicrobial peptides interesting as novel therapeutics. Here, we report on studies of the peptide NLF20 (NLFRKLTHRLFRRNFGYTLR), corresponding to an epitope of the D helix of heparin cofactor II (HCII), a plasma protein mediating bacterial clearance.


METHODS
Peptide effects were evaluated by a combination of in vitro and in vivo methods, including antibacterial, anti-inflammatory and cytotoxicity assays, fluorescence and electron microscopy, and experimental models of endotoxin shock and Pseudomonas aeruginosa sepsis.


RESULTS
The results showed that NLF20 displayed potent antimicrobial effects against the Gram-negative bacteria Escherichia coli and P. aeruginosa, the Gram-positive Bacillus subtilis and Staphylococcus aureus and the fungi Candida albicans and Candida parapsilosis. Importantly, this antimicrobial effect was retained in human blood, particularly for P. aeruginosa. Fluorescence and electron microscopy studies showed that the peptide exerted membrane-breaking effects. In an animal model of P. aeruginosa sepsis, NLF20 reduced bacterial levels, resulting in improved survival. Reduced mortality was also observed in experimental animal models of endotoxin shock, which was paralleled with modulated IFN-γ, IL-10 and coagulation responses.


CONCLUSIONS
Together, these results indicate that functional epitopes of HCII may have therapeutic potential against bacterial infection.
Division of Dermatology and Venereology, Department of Clinical Sciences, Lund University, Lund, Sweden Division of Infection Medicine, Department of Clinical Sciences, Lund University, Lund, Sweden praveen.papareddy@med.lu.se.
Praveen
P
Papareddy
Division of Dermatology and Venereology, Department of Clinical Sciences, Lund University, Lund, Sweden Respiratory Medicine and Allergology, Department of Clinical Sciences, Lund University, Lund, Sweden.
Gopinath
G
Kasetty
Division of Dermatology and Venereology, Department of Clinical Sciences, Lund University, Lund, Sweden.
Martina
M
Kalle
Division of Dermatology and Venereology, Department of Clinical Sciences, Lund University, Lund, Sweden Respiratory Medicine and Allergology, Department of Clinical Sciences, Lund University, Lund, Sweden.
Ravi K V
RK
Bhongir
Division of Infection Medicine, Department of Clinical Sciences, Lund University, Lund, Sweden.
Matthias
M
Mörgelin
Division of Dermatology and Venereology, Department of Clinical Sciences, Lund University, Lund, Sweden Dermatology, LKCMedicine, Nanyang Technological University, Singapore.
Artur
A
Schmidtchen
Department of Pharmacy, Uppsala University, Uppsala, Sweden.
Martin
M
Malmsten
D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology* / Q000627:therapeutic use; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D005658:Fungi / Q000187:drug effects*; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D008297:Male; D008810:Mice, Inbred C57BL; D008826:Microbial Sensitivity Tests; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D010539:Permeability / Q000187:drug effects; D011552:Pseudomonas Infections / Q000188:drug therapy*; D018805:Sepsis / Q000188:drug therapy*; D012772:Shock, Septic / Q000188:drug therapy; D016019:Survival Analysis; D016896:Treatment Outcome
D023181:Antimicrobial Cationic Peptides