TLR2-Dependent Reversible Oxidation of Connexin 43 at Cys260 Modifies Electrical Coupling After Experimental Myocardial Ischemia/Reperfusion

J Cardiovasc Transl Res. 2019 Oct;12(5):478-487. doi: 10.1007/s12265-019-09887-0. Epub 2019 Apr 8.

Abstract

We have shown previously that during myocardial ischemia/reperfusion (MI/R), toll-like receptor 2 (TLR2) signaling regulates connexin 43 (Cx43) subcellular localization and function and dampens arrhythmia formation. We aimed to identify sites capable of TLR2-dependent redox modification within Cx43. Post-ischemic TLR2-/- or wild-type (WT) mouse hearts were analyzed by OxICAT. Cx43 was mutated to exclude redox modification and transfected into HL-1 cardiomyocytes (CM) that were challenged with a TLR2 agonist. We identified Cys260 of Cx43 to be susceptible to reversible oxidation MI/R; TLR2-/- leads to reduced H2O2 production in post-ischemic isolated mitochondria and subsequently reduced oxidation of Cx43 at Cys260. Cx43 was dephosphorylated in WT, while phosphorylation was preserved in TLR2-/-. Mutation of Cx43 (C260A) and lentiviral transfection in HL-1 CM accelerated pacemaker activity and reduced activity after TLR2 ligand stimulation. We here provide evidence for TLR2-dependent reversible oxidation of Cx43 at Cys260, which led to decreased Cx43 phosphorylation and affected CM pacemaker frequency and intercellular communication.

Keywords: Connexin 43; Myocardial ischemia; Redox regulation; Reperfusion; Toll-like receptor 2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials
  • Animals
  • Arrhythmias, Cardiac / genetics
  • Arrhythmias, Cardiac / metabolism*
  • Arrhythmias, Cardiac / pathology
  • Arrhythmias, Cardiac / physiopathology
  • Cell Communication
  • Cell Line
  • Connexin 43 / deficiency
  • Connexin 43 / genetics
  • Connexin 43 / metabolism*
  • Cysteine
  • Disease Models, Animal
  • Heart Rate*
  • Hydrogen Peroxide / metabolism
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mitochondria, Heart / metabolism*
  • Mitochondria, Heart / pathology
  • Myocardial Reperfusion Injury / genetics
  • Myocardial Reperfusion Injury / metabolism*
  • Myocardial Reperfusion Injury / pathology
  • Myocardial Reperfusion Injury / physiopathology
  • Myocytes, Cardiac / metabolism*
  • Myocytes, Cardiac / pathology
  • Oxidation-Reduction
  • Phosphorylation
  • Signal Transduction
  • Toll-Like Receptor 2 / deficiency
  • Toll-Like Receptor 2 / genetics
  • Toll-Like Receptor 2 / metabolism*

Substances

  • Connexin 43
  • GJA1 protein, mouse
  • Tlr2 protein, mouse
  • Toll-Like Receptor 2
  • Hydrogen Peroxide
  • Cysteine