TLR2 ligands attenuate cardiac dysfunction in polymicrobial sepsis via a phosphoinositide 3-kinase-dependent mechanism

Am J Physiol Heart Circ Physiol. 2010 Mar;298(3):H984-91. doi: 10.1152/ajpheart.01109.2009. Epub 2010 Jan 8.

Abstract

Myocardial dysfunction is a major consequence of septic shock and contributes to the high mortality of sepsis. In the present study, we examined the effect of Toll-like receptor 2 (TLR2) ligands, peptidoglycan (PGN), and Pam3CSK4 (Pam3) on cardiac function in cecal ligation and puncture (CLP)-induced sepsis in mice. We also investigated whether the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway is involved in the effect of TLR2 ligands on cardiac function in CLP mice. PGN was administered to C57B6/L mice 1 h before the induction of CLP. Sham surgically operated mice served as a control. Cardiac function indexes (rate of change in left ventricular pressure, stroke work, cardiac output, and ejection fraction) were examined by a microconductance pressure catheter. Cardiac function was significantly decreased 6 h after CLP-induced sepsis compared with sham-operated control. In contrast, PGN administration attenuated CLP-induced cardiac dysfunction. Importantly, the therapeutic treatment with Pam3 1 h after CLP also significantly attenuated cardiac dysfunction in CLP mice. However, the beneficial effect of TLR2 ligands on cardiac dysfunction in CLP-mice was abolished in TLR2-deficient mice. PGN administration significantly increased the levels of phospho-Akt and phospho-GSK-3beta in the myocardium compared with the levels in untreated CLP mice. PI3K inhibition abolished the PGN-induced attenuation of cardiac dysfunction in CLP mice. In conclusion, these data demonstrate that the administration of TLR2 ligands, PGN, or Pam3 attenuates cardiac dysfunction in septic mice via a TLR2/PI3K-dependent mechanism. More significantly, Pam3 therapeutic treatment will have a potential clinical relevance.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cardiac Output / physiology
  • Disease Models, Animal
  • Glycogen Synthase Kinase 3 / physiology
  • Glycogen Synthase Kinase 3 beta
  • Heart / physiopathology
  • Heart Diseases / drug therapy*
  • Heart Diseases / physiopathology
  • Ligands
  • Lipopeptides / therapeutic use*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Peptidoglycan / therapeutic use*
  • Phosphatidylinositol 3-Kinases / physiology*
  • Proto-Oncogene Proteins c-akt / physiology
  • Sepsis / drug therapy*
  • Sepsis / physiopathology
  • Signal Transduction / physiology
  • Stroke Volume / physiology
  • Toll-Like Receptor 2 / genetics
  • Toll-Like Receptor 2 / physiology*

Substances

  • Ligands
  • Lipopeptides
  • Pam(3)CSK(4) peptide
  • Peptidoglycan
  • Tlr2 protein, mouse
  • Toll-Like Receptor 2
  • Phosphatidylinositol 3-Kinases
  • Glycogen Synthase Kinase 3 beta
  • Gsk3b protein, mouse
  • Proto-Oncogene Proteins c-akt
  • Glycogen Synthase Kinase 3