Chemerin/ChemR23 signaling axis is involved in the endothelial protection by KATP channel opener iptakalim

Abstract

Aim: To elucidate the modulation of the chemerin/ChemR23 axis by iptakalim-induced opening of KATP channels and to determine the role of the chemerin/ChemR23 axis in the iptakalim-mediated endothelial protection. Methods: Cultured rat aortic endothelial cells (RAECs) were used. Chemerin secretion and ChemR23 protein expression were investigated using Western blot analysis. The gene expression level of ChemR23 was examined with RT-PCR. In addition, the release of nitric oxide (NO) was measured with a nitric oxide assay. Results: Homocysteine, uric acid, high glucose, or oxidized low-density lipoprotein (ox-LDL) down-regulated the chemerin secretion and ChemR23 gene/protein expression in RAECs as a function of concentration and time, which was reversed by pretreatment with iptakalim (1-10 μmol/L). Moreover, these effects of iptakalim were abolished in the presence of the KATP channel antagonist glibenclamide (1 μmol/L). Both iptakalim and recombinant chemerin restored the impaired NO production in RAECs induced by uric acid, and the effects were abolished by anti-ChemR23 antibodies. Conclusion: Iptakalim via opening KATP channels enhanced the endothelial chemerin/ChemR23 axis and NO production, thus improving endothelial function. © 2011 CPS and SIMM All rights reserved.