FOXO1 impairs whereas statin protects endothelial function in diabetes through reciprocal regulation of Krüppel-like factor 2

Hae-Young Lee, Seock-Won Youn, Hyun-Jai Cho, Yoo-Wook Kwon, Sae-Won Lee, Sung-Jin Kim, Young-Bae Park, Byung-Hee Oh, Hyo-Soo Kim
2012 Cardiovascular Research  
Aims Krüppel-like factor 2 (KLF2) is implicated as a key molecule maintaining endothelial function. This study was designed to evaluate the reciprocal regulation of KLF2 by the forkhead transcription factor FOXO1, and the 3-hydroxy-3methylglutaryl coenzyme A reductase inhibitor atorvastatin, in hyperglycaemic conditions. Methods and results Exposure of human umbilical vein endothelial cells to 30 mM glucose activated FOXO1 and suppressed KLF2. These effects were reversed by FOXO1 small
more » ... ng RNA. Adenoviral transfection of constitutively active FOXO1 suppressed KLF2 expression. Interestingly, atorvastatin inhibited FOXO1 by increasing phosphorylation and also by inhibiting nuclear localization and replenished KLF2 in high-glucose conditions. This effect of atorvastatin was attenuated by mevalonate. Chromatin immunoprecipitation analysis demonstrated that glucose increased whereas atorvastatin decreased FOXO1 binding to the promoter region of the KLF2 gene. In the vessels of Otsuka Long-Evans Tokushima Fatty rats, animal models of type 2 diabetes, FOXO1 was activated and KLF2 was suppressed, and this was reversed by atorvastatin treatment. The arteries from Otsuka Long-Evans Tokushima Fatty rats showed impairment of endothelium-dependent vasodilatation, and both atorvastatin and KLF2 gene therapies restored it. Conclusions Suppression of KLF2 by FOXO1 may be a plausible mechanism of diabetic endothelial dysfunction. High-glucoseinduced, FOXO1-mediated KLF2 suppression was reversed by atorvastatin, suggesting that intensive statin treatment could be a therapeutic option in diabetic vascular dysfunction. ---
doi:10.1093/cvr/cvs283 pmid:23002242 fatcat:ptzcj7jspzcffoaqp46xq7mgvi