Involvement of O-GlcNAcylation in vascular damage during septic shock

Abstract

Septic shock is characterized by a systemic inflammatory response syndrome (SIRS) causing hypotension and systemic hypoperfusion leading to altered cellular metabolism. This pathology is accompanied by vascular leakage due to endothelial damage. O-GlcNAcylation is a post-translational modification involved in the stress response. Recently, stimulation of O-GlcNAcylation has been shown to improve cardiovascular function in several murine models of septic shock. An O-GlcNAcylome study identified VE-cadherin and ZO-1 as potential interesting target, which are two major proteins involved in vascular leakage. We hypothesize that stimulation of O-GlcNAcylation may be involved in the regulation of vascular damage during early septic shock. Septic shock was induced in rats ( n = 10–12) by cecal ligation and punction (CLP). At 8 h and 22 h post-surgery, CLP rats receive fluid therapy with or without OGA inhibitor, NButGT (10 mg/kg) to increase O-GlcNAcylation levels. Cardiovascular functions were assessed and aortic arteries and heart were harvested and analyzed at 24 h post-surgery. Expression levels of O-GlcNAcylation, VE-cadherin and ZO-1 were assessed by western blot. The localization of VE-cadherin and ZO-1 was analyzed in the aorta. Evaluation of O-GlcNAcylation on VE-cadherin and ZO-1 were performed by immunoprecipitation and wheat germ agglutinin (WGA) gel. The results of the involvement of NButGT treatment on CLP rats show a cardiovascular improvement through mean arterial pressure (SHAM: 101.2 ± 1.65; CLP: 87.8 ± 4.67; NButGT: 102.9 ± 3.42; n = 10–12; P < 0.05). VE-Cadherin expression in the heart seems to be decreased in CLP group and this expression was significantly reversed with the NButGT treatment (SHAM: 1.00 ± 0.05; CLP: 0.86 ± 0.11; NButGT: 1.27 ± 0.10; n = 6–12; P < 0.05). WGA gel has made it possible to confirm that VE-Cadherin is O-GlcNAcylated. This study will allow us to better understand the mechanisms involved in vascular damage following the improvement of cardiovascular functions by O-GlcNAcylation stimulation in our septic shock model.