Thrombin-derived C-terminal fragments aggregate and scavenge bacteria and their proinflammatory products

Research output: Contribution to journalArticle

Abstract

Thrombin-derived C-terminal peptides (TCPs), including a major 11-kDa fragment (TCP96), are produced through cleavage by human neutrophil elastase and aggregate lipopolysaccharide (LPS) and the Gram-negative bacterium Escherichia coli. However, the physiological roles of TCP96 in controlling bacterial infections and reducing LPS-induced inflammation are unclear. Here, using various biophysical methods, in silico molecular modeling, microbiological and cellular assays, and animal models, we examined the structural features and functional roles of recombinant TCP96 (rTCP96) in the aggregation of multiple bacteria and the Toll-like receptor (TLR) agonists they produce. We found that rTCP96 aggregates both Gram-negative and Gram-positive bacteria, including Staphylococcus aureus and Pseudomonas aeruginosa, and their cell-wall components LPS, lipid A, and lipoteichoic acid (LTA). The Gram-negative bacteria E. coli and P. aeruginosa were particularly sensitive to aggregation-induced bacterial permeabilization and killing. As a proof of concept, we show that rTCP96 reduces LPS-induced NF-κB activation in human monocytes, as well as in mouse models of LPS-induced subcutaneous inflammation. Moreover, in a mouse model of subcutaneous inoculation with P. aeruginosa, rTCP96 reduced bacterial levels. Together, these results link TCP-mediated aggregation of endotoxins and bacteria in vitro to attenuation of inflammation and bacterial levels in vivo.

Details

Authors
Organisations
External organisations
  • A*Star, Bioinformatics Institute (BII)
  • University of Southampton
  • University of Copenhagen
  • National University of Singapore
  • Bispebjerg Hospital
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Microbiology in the medical area
Original languageEnglish
Pages (from-to)3417-3430
Number of pages14
JournalJournal of Biological Chemistry
Volume295
Issue number11
Publication statusPublished - 2020
Publication categoryResearch
Peer-reviewedYes