Aryl hydrocarbon receptor mediates indoxyl sulfate-induced cellular senescence in human umbilical vein endothelial cells

Aim: vascular senescence,which is accelerated in individuals with chronic kidney disease (ckd),contributes to the development of cardio-renal syndrome,and various uremic toxins may play important roles in the mechanisms underlying this phenomenon. we recently reported that indoxyl sulfate (is),a uremic toxin,directly activates aryl hydrocarbon receptor (ahr) and generates oxidative stress through nadph oxidase-4 in human umbilical vein endothelial cells (huvecs). in the current study,we sought to examine whether is regulates sirtuin 1 (sirt1) and affects endothelial senescence via ahr activation.methods: huvecs were incubated with 500 μmol/l of is for the indicated time periods. in order to evaluate changes in the senescence of the huvecs,the number of senescence-associated β-galactosidase (sa β-gal)-positive cells was determined using an image analysis software program. the intracellular nicotinamide phosphoribosyltransferase (inampt) activity,cellular nad＋/nadph ratio and sirt1 activity were analyzed according to a colorimetric assay to determine the mechanism of cellular senescence. furthermore,we evaluated the involvement of ahr in the senescence-related changes induced by is using ahr antagonists.results: is decreased the inampt activity,nad＋/nadph ratio and sirt1 activity,resulting in an increase in the percentage of sa β-gal-positive cells. on the other hand,the ahr antagonists restored the is-induced decrease in the nad＋ content in association with an improvement in the inampt activity and ameliorated the senescence-related changes. taken together,these results indicate that is impairs the inampt-nad＋-sirt1 system via ahr activation,which in turn promotes endothelial senescence.conclusions: the is-ahr pathway induces endothelial senescence. therefore,blocking the effects of ahr in the endothelium may provide a new therapeutic tool for treating cardio-renal syndrome. © 2014,japan atherosclerosis society. all rights reserved.