Advanced glycation end products (AGEs) and high glucose in endothelial cells: gene expression analysis
Tali Zitman-Gal1, Janice Green1, Metsada Pasmanik-Chor2, Varda Oron-Karni2 & Jacques Bernheim1,3
Background: Elevation of blood and tissue concentrations of glucose and advanced glycation end products (AGEs) may play a relevant role in the occurrence of atherosclerosis, arteriosclerosis and diabetic complications. To evaluate the impact of elevated extracellular AGEs and different glucose concentrations we studied the gene expressions and the underlying pathways which may lead to endothelial inflammation.
Methods: Fresh human umbilical vein cord endothelial cells (HUVEC) were treated in vitro in the presence of elevated extracellular glucose concentrations (150500 mg/dl) with and without AGEHSA. The ethics review committee of Meir Medical Center approved the study. Affymetrix GeneChip Human arrays were used for gene expression analysis. Genes of interest differentially expressed (P<0.05) were further validated using real-time PCR and western blot.
Results: Microarray analysis revealed significant changes in some gene expressions in the presence of the different stimuli, suggesting different pathways for activation. Validation of the increased expressions of selected genes was examined as follows: thioredoxininteracting protein (TXNIP), NFKB p50, IL6, IL8 and receptor of AGEs (RAGE). The combined incubation of AGEs and the highest glucose concentrations (500 mg/dl) induced a blunting action on the expression of these genes. A significant decrease in NF-κB p65 and TXNIP protein expressions was also observed in the highest glucose concentration in comparison with the results observed with the lower extracellular glucose concentrations.
Conclusion: A diabetic like environment showed an unexpected blunting action of AGEs in the presence of the highest glucose concentrations on endothelial inflammatory gene expressions. Such phenomenon will have to be explained through the cellular interactive pathways involved in such processes.