Fig. 8: SCFAs increase expression of Aicda- and Prdm1-targeting miRNAs by enhancing histone acetylation of related miRNA host genes.

a Primary mouse B cells, CH12F3 B cells, and human B cells were stimulated with indicated stimuli for 60 h in the presence of nil, butyrate (500 μM), or propionate (2000 μM). Ex vivo B cells were isolated from mice injected with NP-LPS and on plain water or SCFA water for 21 days. Acetylated-histone H3 (H3K9ac), histone H3, and β-actin proteins as detected by immunoblotting. Data are one representative of three independent experiments. b Relative densities of the Ac-histone H3 bands normalized to histone H3 and β-actin levels. c, d B cells stimulated with LPS plus IL-4 in the presence of nil or butyrate for 60 h. Expression of the Aicda- and Prdm1-targeting miRNAs, and irrelevant miRNAs as analyzed by qRT-PCR (c). Relative abundance of H3K9ac/K14ac in miRNA host genes (HGs) as analyzed by ChIP-qPCR (d). e Schematic diagram of the luciferase reporter constructs-containing 3′UTRs of Aicda and Prdm1 mRNAs and their mutant (mut) counterparts. f Surface CD19 and IgA on CH12F3 B cells stimulated for 96 h in the presence of nil, butyrate (500 μM), propionate (2000 μM), or VPA (500 μM) as analyzed by flow cytometry. Data are one representative of 3 independent experiments yielding comparable results. g, miRNA expression in CH12F3 cells stimulated for 24 h in the presence of nil or butyrate, as analyzed by qRT-PCR. Data in c, d, and g are ratios to stimulated B cells cultured with nil (set as 1; means ± SEM of three independent experiments). h Luciferase activity in CH12F3 cells transfected with luciferase reporter vectors-containing wild-type or mutated Aicda or Prdm1 3′UTRs after 24 h treatment with nil or butyrate. Luciferase activity was measured 6 h after transfection, and normalized relative to luciferase activity in B cells cultured with nil. Data in h are ratios to transfected B cells cultured with nil (set as 100%; means ± SEM of three independent experiments). *p < 0.05, **p < 0.01, ns: not significant (unpaired t test). The source data are provided in Source Data file.