GSK3β and VDAC Involvement in ER Stress and Apoptosis Modulation during Orthotopic Liver Transplantation

Mohamed Zaouali,Arnau Panisello,Joan Roselló-Catafau,Emma Folch,René Adam,Anabela Rolo,Alexandre Lopez,Carlos Palmeira,Teresa Carbonell,Agustin Garcia-Gil,Carlos Castro

doi:10.3390/ijms18030591

Abstract

We investigated the involvement of glycogen synthase kinase-3β (GSK3β) and the voltage-dependent anion channel (VDAC) in livers subjected to cold ischemia–reperfusion injury (I/R) associated with orthotopic liver transplantation (OLT). Rat livers were preserved in University of Wisconsin (UW) and Institute Georges Lopez (IGL-1) solution, the latter enriched or not with trimetazidine, and then subjected to OLT. Transaminase (ALT) and HMGB1 protein levels, glutamate dehydrogenase (GLDH), and oxidative stress (MDA) were measured. The AKT protein kinase and its direct substrates, GSK3β and VDAC, as well as caspases 3, 9, and cytochrome C and reticulum endoplasmic stress-related proteins (GRP78, pPERK, ATF4, and CHOP), were determined by Western blot. IGL-1+TMZ significantly reduced liver injury. We also observed a significant phosphorylation of AKT, which in turn induced the phosphorylation and inhibition of GSK3β. In addition, TMZ protected the mitochondria since, in comparison with IGL-1 alone, we found reductions in VDAC phosphorylation, apoptosis, and GLDH release. All these results were correlated with decreased ER stress. Addition of TMZ to IGL-1 solution increased the tolerance of the liver graft to I/R injury through inhibition of GSK3β and VDAC, contributing to ER stress reduction and cell death prevention.

Highlights

Cold ischemia–reperfusion (I/R) injury is a major cause of primary graft non-function after liver transplantation (LT) [1]
In this study we evaluated whether the addition of trimetazidine to IGL-1 solution protected liver grafts against cold I/R associated with liver transplantation, and whether this protection might be mediated by changes in the protein levels of AKT and its direct substrate glycogen synthase kinase-3β (GSK3β) after 8 h of ischemic cold storage followed by 24 h orthotopic liver transplantation
This was associated with a decrease in the protein levels of phosphorylated GSK3β (p-GSK3β), the inactive form of GSK3β, in livers preserved in University of Wisconsin (UW) solution (Figure 1B)

Summary

Introduction

Cold ischemia–reperfusion (I/R) injury is a major cause of primary graft non-function after liver transplantation (LT) [1]. The benefits of IGL-1 solution are mainly associated with the nitric oxide generation and the prevention of endoplasmic reticulum (ER) stress and inflammatory response [4]. In previous publications, we have shown that the use of additives such as trimetazidine (TMZ) to UW [5,6] and IGL-1 solutions [7,8] contributes to increasing the preservation of steatotic liver grafts (which are more vulnerable than non-steatotic ones) against cold I/R injury [9]. We proved that the presence of TMZ in IGL-1 solution increases the liver graft protection against cold I/R associated with orthotopic liver transplantation (OLT) by promoting effective prevention of mitochondrial damage [10]. The underlying mechanisms of mitochondrial protection responsible for these IGL-1 benefits have not been fully investigated

Methods

Results

Conclusion