Sodium butyrate attenuates angiotensin II‐induced cardiac hypertrophy by inhibiting COX2/PGE2 pathway via a HDAC5/HDAC6‐dependent mechanism

Sodium butyrate (NaBu) is reported to play important roles in a number of chronic diseases. The present work is aimed to investigate the effect of NaBu on angiotensin II (Ang II)‐induced cardiac hypertrophy and the underlying mechanism in in vivo and in vitro models. Sprague Dawley rats were infused with vehicle or Ang II (200 ng/kg/min) and orally administrated with or without NaBu (1 g/kg/d) for two weeks. Cardiac hypertrophy parameters and COX2/PGE2 pathway were analysed by real‐time PCR, ELISA, immunostaining and Western blot. The cardiomyocytes H9C2 cells were used as in vitro model to investigate the role of NaBu (2 mmol/L) in inhibition of Ang II‐induced cardiac hypertrophy. NaBu significantly attenuated Ang II‐induced increase in the mean arterial pressure. Ang II treatment remarkably increased cardiac hypertrophy as indicated by increased ratio of heart weight/body weight and enlarged cardiomyocyte size, extensive fibrosis and inflammation, as well as enhanced expression of hypertrophic markers, whereas hearts from NaBu‐treated rats exhibited a significant reduction in these hypertrophic responses. Mechanistically, NaBu inhibited the expression of COX2/PGE2 along with production of ANP and phosphorylated ERK (pERK) stimulated by Ang II in in vivo and in vitro, which was accompanied by the suppression of HDAC5 and HDAC6 activities. Additionally, knocking down the expression of HDAC5 and HDAC6 via gene‐editing strategy dramatically blocked Ang II‐induced hypertrophic responses through COX2/PGE2 pathway. These results provide solid evidence that NaBu attenuates Ang II‐induced cardiac hypertrophy by inhibiting the activation of COX2/PGE2 pathway in a HDAC5/HDAC6‐dependent manner.