HDAC5 negatively regulated MEF2 transcriptional activation and KFL2 expression. (A) HUVECs were infected with Ad-Flag-HDAC5. Twenty-four hours later, cells were conditioned under static conditions (first lane) or flow (second lane) for 1 hour. Immunoprecipitation was performed with Flag antibody–conjugated agarose. MEF2C and Flag-HDAC5 were detected by probing with anti-MEF2C and anti-Flag antibodies. (B-C) HUVECs were transfected with 3xMEF2-luciferase or −221/+1 KLF2 promoter or −221/+1 MEF2 binding site–deleted KLF2 promoter reporter gene together with HDAC5-S/A or pcDNA as control. Twenty-four hours later, cells were conditioned with static or flow for 8 hours. Luciferase activities were assayed by Promega Luciferase assay kit. *P < .05 compared with control (static). #P < .05 compared with that treated with flow + pcDNA. Error bars represent ±SEM.