Effect of uraemia on endothelial cell damage is mediated by the integrin linked kinase pathway

Abstract

Key pointsr Patients with chronic kidney disease have a higher risk of developing cardiovascular diseases than the general population. Their vascular endothelium is dysfunctional, among other things, because it is permanently exposed to uraemic toxins, several of which have poor clearance by conventional dialysis.r Recent studies have demonstrated the important role of integrin-linked kinase (ILK) in the maintenance of endothelial integrity and in this study we investigate the involvement of ILK in the mechanism underlying vascular endothelial damage that occurs in uraemia.r For the first time, we demonstrate the implication of ILK in the protection against endothelial cell damage (inhibition of proliferation, toxicity, oxidative stress and programed cell death) induced by uraemic serum from chronic kidney disease patients and uraemic toxins.r This molecular mechanism may have clinical relevance because it highlights the importance of maintaining high levels of ILK activity to help preserve endothelial integrity, at least in early stages of chronic kidney disease.Abstract Patients with chronic kidney disease (CKD) have a higher risk of developing cardiovascular diseases. Their vascular endothelium is dysfunctional, among other things, because it is permanently exposed to uraemic toxins, several of which, mostly protein-bound compounds such as indoxyl sulfate (IS) and p-cresyl sulphate, having poor clearance by conventional dialysis, induce endothelial toxicity. However, the molecular mechanism by which uraemic toxins regulate early stages of endothelial dysfunction remains unclear. Recent studies have demonstrated the important role of integrin-linked kinase (ILK) in the maintenance of endothelial integrity. In this study, we investigate the involvement of ILK in the mechanism underlying vascular endothelial damage that occurs in uraemia. First, we show that incubation of EA.hy926 cells with human uraemic serum from CKD patients upregulates ILK activity. This ILK activation also occurs when the cells are exposed to IS (25-100 μg ml −1 ), p-cresol (10-100 μg ml −1 ) or both combined, compared to human serum control. Next, we observed that high doses of both toxins together induce a slight decrease in cell proliferation and increase apoptosis and reactive oxygen species production. Interestingly, these toxic effects displayed a strong increase when the ILK protein is knocked down by small interfering RNA, even at low doses of uraemic toxins. Abrogation of AKT has demonstrated the ILK/AKT signalling pathway involved in these processes. This study has demonstrated the implication of ILK in the protection against endothelial cell damage induced by uraemic toxins, a molecular mechanism that could play a protective role in the early stages of endothelial dysfunction observed in uraemic patients.

Peripheral insulin resistance in ILK-depleted mice by reduction of GLUT4 expression

“…3A and B) and its consequently reduced activity, determined as the phosphorylation state in downstream substrates GSK3B on serine 9 and AKT on serine 473 ( Fig. 3C and D) (Troussard et al 2003, Edwards et al 2005, García-Jérez et al 2015. Since AKT is shared as a downstream component of the IR/IRS-1 network during the GLUT4 modulation (Carnagarin et al 2015), we also studied the AKT phosphorylation state on threonine 308, which was unchanged between groups ( Fig.…”

“…Insulin binding to IR/IRS-1 activates the phosphorylation of AKT in both serine 473 and threonine 308 residues (Carnagarin et al 2015), which is also an ILK downstream effector (Troussard et al 2003, Edwards et al 2005, García-Jérez et al 2015. In order to elucidate whether ILK depletion was affecting the IR/IRS-1/AKTmediated insulin response, we studied the behavior of this pathway under the stimulation of different insulin states in vivo and in vitro.…”

An overview of AVF maturation and endothelial dysfunction in an advanced renal failure

“…Arteriovenous fistula anastomoses need swift proliferation of endothelial cells to restore the barrier, permeability, and biochemical monitoring roles of endothelial cells in managing vascular repair, local thrombosis, neointimal hyperplasia, and inflammation [39]. Because the migration and proliferation of endothelial cells are restricted by uraemia, and because uraemia causes abnormal vascular remodelling, neointimal hyperplasia can sometimes be found at the point of anastomosis of VA [40,41]. This results in primary access failure and ineffective dialysis [42].…”

North American ginseng inhibits myocardial NOX2-ERK1/2 signaling and tumor necrosis factor-α expression in endotoxemia

“…In cultured cardiomyocytes, superoxide generation was determined using CellROX® deep red reagent (Thermo Scientific, Mississauga, Ontario) as previously described [20,21]. The CellROX deep red reagent is a cell-permeable and fluorogenic probe designed to assess ROS levels in live cells.…”