Abstract P320: The Gut Microbial Metabolite Butyrate Suppresses Cardiac Hypertrophy Via An Epigenetic Mechanism

Introduction: Short-chain fatty acids (SCFA) are one of the gut microbial metabolites that can influence host health and disease. We previously reported that gut dysbiosis is associated with heart failure, and that the proportion of butyrate-producing bacteria is decreased in the gut of patients with heart failure. Purpose: We investigated the molecular mechanism of butyrate in the development of cardiac hypertrophy. Methods and Results: Single-cell transcriptome analysis and co-expression network analysis revealed that G protein-coupled receptors for short-chain fatty acid receptors were not expressed in cardiomyocytes and that Olfr78 was expressed in vascular smooth muscle cells in the heart. On the other hand, treatment with butyrate inhibited ET1-induced and isoproterenol (ISO)-induced hypertrophic growth in cultured neonatal rat cardiomyocytes. Moreover, butyrate increased the acetylation levels of histone H3, suggesting the inhibitory effect of butyrate on HDAC. In addition, butyrate caused the degradation of HDAC2 and up-regulation of Inpp5f, encoding inositol polyphosphate-5-phosphatase f, leading to a significant decrease in the phosphorylation levels of Akt and glycogen synthase kinase 3β (GSK3β). Finally, intraperitoneal injection of butyrate inhibited ISO-induced cardiac hypertrophy in mice. These results suggest that butyrate protects against hypertrophic responses via suppression of the Akt-GSK3β pathway through HDAC inhibition. Conclusion: In the heart, there were no known short-chain fatty acid receptors in cardiomyocytes. However, butyrate was shown to have an epigenetic mechanism in suppressing effect on cardiomyocyte hypertrophy via suppression of HDAC2-Akt-GSK3β axis. Our results uncover a potential link between dysbiosis of intestinal microbiota and the development of cardiac hypertrophy.