Lipoproteins/peptides are sepsis-inducing toxins from bacteria that can be neutralized by synthetic anti-endotoxin peptides

Sci Rep. 2015 Sep 22:5:14292. doi: 10.1038/srep14292.

Abstract

Sepsis, a life-threatening syndrome with increasing incidence worldwide, is triggered by an overwhelming inflammation induced by microbial toxins released into the bloodstream during infection. A well-known sepsis-inducing factor is the membrane constituent of Gram-negative bacteria, lipopolysaccharide (LPS), signalling via Toll-like receptor-4. Although sepsis is caused in more than 50% cases by Gram-positive and mycoplasma cells, the causative compounds are still poorly described. In contradicting investigations lipoproteins/-peptides (LP), lipoteichoic acids (LTA), and peptidoglycans (PGN), were made responsible for eliciting this pathology. Here, we used human mononuclear cells from healthy donors to determine the cytokine-inducing activity of various LPs from different bacterial origin, synthetic and natural, and compared their activity with that of natural LTA and PGN. We demonstrate that LP are the most potent non-LPS pro-inflammatory toxins of the bacterial cell walls, signalling via Toll-like receptor-2, not only in vitro, but also when inoculated into mice: A synthetic LP caused sepsis-related pathological symptoms in a dose-response manner. Additionally, these mice produced pro-inflammatory cytokines characteristic of a septic reaction. Importantly, the recently designed polypeptide Aspidasept(®) which has been proven to efficiently neutralize LPS in vivo, inhibited cytokines induced by the various non-LPS compounds protecting animals from the pro-inflammatory activity of synthetic LP.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Bacterial Agents / chemical synthesis
  • Anti-Bacterial Agents / pharmacology*
  • Cytokines / biosynthesis
  • Disease Models, Animal
  • Endotoxemia / drug therapy
  • Endotoxemia / etiology
  • Endotoxemia / metabolism
  • Endotoxemia / mortality
  • Endotoxins / adverse effects*
  • Endotoxins / antagonists & inhibitors*
  • Female
  • Gram-Negative Bacteria / immunology
  • HEK293 Cells
  • Humans
  • Leukocytes, Mononuclear / immunology
  • Leukocytes, Mononuclear / metabolism
  • Lipopolysaccharides / adverse effects
  • Lipopolysaccharides / antagonists & inhibitors
  • Lipopolysaccharides / chemistry
  • Lipoproteins / adverse effects*
  • Lipoproteins / antagonists & inhibitors*
  • Lipoproteins / chemistry
  • Macrophages / immunology
  • Macrophages / metabolism
  • Mice
  • Peptides / chemical synthesis
  • Peptides / pharmacology*
  • Peptidoglycan / adverse effects
  • Sepsis / drug therapy
  • Sepsis / etiology*
  • Sepsis / metabolism
  • Sepsis / mortality
  • Staphylococcus aureus / immunology
  • Teichoic Acids / adverse effects

Substances

  • Anti-Bacterial Agents
  • Cytokines
  • Endotoxins
  • Lipopolysaccharides
  • Lipoproteins
  • Peptides
  • Peptidoglycan
  • Teichoic Acids
  • lipoteichoic acid