Cellular Thiols Redox Status: a Switch for NF-κB Activation During Myocardial Post-ischaemic Reperfusion

Abstract

A. Cargnoni, C. Ceconi, G. Gaia, L. Agnoletti and R. Ferrari. Cellular Thiols Redox Status: a Switch for NF-κB Activation During Myocardial Post-ischaemic Reperfusion. Journal of Molecular and Cellular Cardiology (2002)34 , 997–1005. Myocardial ischaemia/reperfusion induces NF-κB activation, but little is known about the stimuli through which it occurs. Aims of the study were to investigate whether: (a) oxidative stress induced by ischaemia/reperfusion is linked with NF-κB activation; (b) counteraction of oxidative stress by N-acetyl cysteine (NAC) reduces NF-κB activation. At this purpose, in isolated rat hearts, we induced mild (15min) and severe (30min) ischaemia; a group of the hearts submitted to severe ischaemia were treated with NAC. Our data indicate that reperfusion after severe ischaemia activates NF-κB: the presence of p65 in the nuclear extracts was 274.5±18.6% vs aerobia; (P<0.05) and an induced DNA-binding activity was detected. NF-κB translocation occurs in parallel with myocardial decrease in reduced glutathione and protein -SH (from 9.2±0.4 to 5.4±0.3nmol/mg prot, P<0.01, and from 350.3±16.6 to 296.0±9.1nmol/mg prot, P<0.05) and accumulation of oxidised glutathione—GSSG—(from 0.075±0.005 to 0.118±0.007nmol/mg prot, P<0.01). When ischaemia/reperfusion does not result in any oxidative stress (in mild ischaemia or severe ischaemia plus NAC), NF-κB does not translocate. A significant correlation was found between the activation of NF-κB and the accumulation of GSSG in the myocardium. Our data indicate that an oxidative shift of cellular thiolic pools can modulate the genic transcription of the heart through NF-κB activation.