HDAC9 and colitis: Previous reports have shown that butyrate acts through different signaling pathways, including activation of G protein-coupled receptors (GPCRs) and inhibition of histone deacetylase (HDAC).40 Furthermore, butyrate stabilizes HIF-1α in intestinal epithelial cells, sustaining their function in homeostasis and in colitis models.41,44 HIF-1α forms a heterodimeric transcription factor with the aryl hydrocarbon receptor nuclear translocator (ARNT)7.