Acetate supplementation increases brain histone acetylation and inhibits histone deacetylase activity and expression

Acetate supplementation increases brain, heart, and liver acetyl-CoA levels and reduces lipopolysaccharide-induced neuroinflammation. Because intracellular acetyl-CoA can be used to alter histone acetylation-state, using Western blot analysis, we measured the temporal effect that acetate supplementation had on brain and liver histone acetylation following a single oral dose of glyceryl triacetate (6 g/kg). In parallel experiments, we measured the effect that acetate supplementation had on histone deacetylase (HDAC) and histone acetyltransferase (HAT) enzymic activities and the expression levels of HDAC class I and II enzymes using Western blot analysis. We found that acetate supplementation increased the acetylation-state of brain histone H4 at lysine 8 at 2 and 4 h, histone H4 at lysine 16 at 4 and 24 h, and histone H3 at lysine 9 at 4 h following treatment. No changes in other forms of brain or liver H3 and H4 acetylation-state were found at any post-treatment times measured. Enzymic HAT and HDAC assays on brain extracts showed that acetate supplementation had no effect on HAT activity, but significantly inhibited by 2-fold HDAC activity at 2 and 4 h post-treatment. Western blot analysis demonstrated that HDAC 2 levels were decreased at 4 h following treatment. Based on these results, we conclude that acetyl-CoA derived from acetate supplementation increases brain histone acetylation-state by reducing HDAC activity and expression.     

Butyrate-induced GPR41 activation inhibits histone acetylation and cell growth

Butyrate has been recently identified as a natural ligand of the G-protein-coupled receptor 41(GPR41).In addition,it is an inhibitor of histone deacetylase(HDAC).Butyrate treatment results in the hyperacetylation of histones,with resultant multiple biological effects including inhibition of proliferation,induction of cell cycle arrest,and apoptosis,in a variety of cultured mammalian cells.However,it is not clear whether GPR41 is actively involved in the above-mentioned processes.In this study,we generated a stable cell line expressing the hGPR41 receptor in order to investigate the involvement of GPR41 on butyrate-induced biochemical and physiologic processes.We found that GPR41 activation may be a compensatory mechanism to counter the increase in histone H3 acetylation levels induced by butyrate treatment.Moreover,GPR41 had an inhibitory effect on the anti-proliferative,pro-apoptotic effects of butyrate.GPR41 expression induced cell cycle arrest at the G1-stage,while its activation by butyrate can cause more cells to pass the G1 checkpoint.These results indicated that GPR41 was associated with histone acetylation and might be involved in the acetylation-related regulation of cell processes including proliferation,apoptosis,and the cell cycle.