Proteinases of common pathogenic bacteria degrade and inactivate the antibacterial peptide LL-37

• Effectors of the innate immune system, the anti-bacterial peptides, have pivotal roles in preventing infection at epithelial surfaces. Here we show that proteinases of the significant human pathogens Pseudomonas aeruginosa, Enterococcus faecalis, Proteus mirabilis and Streptococcus pyogenes, degrade the antibacterial peptide LL-37. Analysis by mass spectrometry of fragments generated by P. aeruginosa elastase in vitro revealed that the initial cleavages occurred at Asn-Leu and Asp-Phe, followed by two breaks at Arg-Ile, thus inactivating the peptide. Proteinases of the other pathogens also degraded LL-37 as determined by SDS-PAGE. Ex vivo, P. aeruginosa elastase induced LL-37 degradation in human wound fluid, leading to enhanced bacterial survival. The degradation was blocked by the metalloproteinase inhibitors GM6001 and 1, 10-phenantroline (both of which inhibited P. aeruginosa elastase, P. mirabilis proteinase, and E. faecalis gelatinase), or the inhibitor E64 (which inhibited S. pyogenes cysteine proteinase). Additional experiments demonstrated that dermatan sulphate and disaccharides of the structure [DeltaUA(2S)-GalNAc(4,6S)], or sucroseoctasulphate, in-hibited the degradation of LL-37. The results indicate that proteolytic degradation of LL-37 is a common virulence mechanism and that molecules which block this degradation could have therapeutic potential.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Dermatologi och venereologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Dermatology and Venereal Diseases (hsv//eng)

Nyckelord

Endopeptidases/*metabolism

Glycosaminoglycans/pharmacology

Microbial Sensitivity Tests

Human

Molecular Sequence Data

Pancreatic Elastase/metabolism

Neutrophils

Protease Inhibitors/pharmacology

Pseudomonas aeruginosa/enzymology/pathogenicity

Spectrum Analysis

Mass

Sulfur/metabolism

Wound Infection/microbiology

Virulence

Disaccharides/chemistry/pharmacology

Bacterial Infections/microbiology

Bacteria/*drug effects/*metabolism/pathogenicity

Antimicrobial Cationic Peptides/genetics/*metabolism/*pharmacology

Amino Acid Sequence

Publikations- och innehållstyp

art (ämneskategori)

ref (ämneskategori)