Prominent action of butyrate over β-hydroxybutyrate as histone deacetylase inhibitor, transcriptional modulator and anti-inflammatory molecule

Abstract

Butyrate and R-β-hydroxybutyrate are two related short chain fatty acids naturally found in mammals. Butyrate, produced by enteric butyric bacteria, is present at millimolar concentrations in the gastrointestinal tract and at lower levels in blood; R-β-hydroxybutyrate, the main ketone body, produced by the liver during fasting can reach millimolar concentrations in the circulation. Both molecules have been shown to be histone deacetylase (HDAC) inhibitors, and their administration has been associated to an improved metabolic profile and better cellular oxidative status, with butyrate inducing PGC1α and fatty acid oxidation and R-β-hydroxybutyrate upregulating oxidative stress resistance factors FOXO3A and MT2 in mouse kidney. Because of the chemical and functional similarity between the two molecules, we compared here their impact on multiple cell types, evaluating i) histone acetylation and hydroxybutyrylation levels by immunoblotting, ii) transcriptional regulation of metabolic and inflammatory genes by quantitative PCR and iii) cytokine secretion profiles using proteome profiling array analysis. We confirm that butyrate is a strong HDAC inhibitor, a characteristic we could not identify in R-β-hydroxybutyrate in vivo nor in vitro. Butyrate had an extensive impact on gene transcription in rat myotubes, upregulating PGC1α, CPT1b, mitochondrial sirtuins (SIRT3-5), and the mitochondrial anti-oxidative genes SOD2 and catalase. In endothelial cells, butyrate suppressed gene expression and LPS-induced secretion of several pro-inflammatory genes, while R-β-hydroxybutyrate acted as a slightly pro-inflammatory molecule. Our observations indicate that butyrate induces transcriptional changes to a higher extent than R-β-hydroxybutyrate in rat myotubes and endothelial cells, in keep with its HDAC inhibitory activity. Also, in contrast with previous reports, R-β-hydroxybutyrate, while inducing histone β-hydroxybutyrylation, did not display a readily detectable HDAC inhibitor activity and exerted a slight pro-inflammatory action on endothelial cells.

Modulation of Cellular Biochemistry, Epigenetics and Metabolomics by Ketone Bodies. Implications of the Ketogenic Diet in the Physiology of the Organism and Pathological States

“…However, more recent data from Chriett et al did not confirm the function of BHB as a histone deacetylase inhibitor. Experiments performed on multiple cell lines, including HEK293 cells, myotubes (L6) and endothelial cells (HMEC-1), showed that BHB administration did not increase histone acetylation, and BHB treatment of crude nuclear extracts did not inhibit histone deacetylase catalytic activity [31]. These data are in line with the study performed by Xie et al that presented a BHB dose-dependent induction of β-hydroxybutyrylation on multiple histone lysines with only marginal changes in the acetylation patterns [25].…”

Skin Cutibacterium acnes Mediates Fermentation to Suppress the Calcium Phosphate-Induced Itching: A Butyric Acid Derivative with Potential for Uremic Pruritus

“…As shown in Figure 2, activation of AcH3K9 is detectable in KERTr cells or mouse skin treated with butyric acid or BA-NH-NH-BA, suggesting that butyric acid or BA-NH-NH-BA may down-regulate the production of IL-6 via the inhibition of HDACs favoring histone acetylation [75]. A modeling study demonstrated that trichostatin A (TSA) exerts its inhibitory effect on HDAC inhibitor by disrupting interactions between the lysine side chain of histone H3 and the acetyl group of HDAC [76].…”

Dietary Fatty Acids and Microbiota-Brain Communication in Neuropsychiatric Diseases

“…As observed for the role of SCFAs in depression, butyrate can normalize BDNF expression and depression-like behaviors in animals [200], through mechanisms involving BDNF-5HT synergistic modulation as well as HDAC inhibition and potentiation of 5HT transmission [204]. Not only butyrate administration can promote the recovery of BDNF expression and memory impairment [249], but its activity as HDAC inhibitor provides a mechanistic evidence for the ability to suppress several LPS-induced pro-inflammatory factors [250], which are recognized components of SCZ pathogenesis [251]. Strikingly, stress-induced derangement of gut microbial composition and changes in brain BDNF expression are associated to the alteration of NMDA receptor subunits, such as for the decrease of GluN2A subunit in the hippocampus and cortex of GF mice [32].…”