Fasting-induced JMJD3 histone demethylase epigenetically activates mitochondrial fattyacid beta-oxidation

Jumonji D3 (JMJD3) histone demethylase epigenetically regulates development, differentiation, and immunity by demethylating a gene-repression histone mark, H3K27-me3, but a role for JMJD3 in metabolic regulation has not been described. SIRT1 deacetylase maintains energy balance during fasting by directly activating both hepatic gluconeogenic and mitochondrial fatty acid beta-oxidation genes, but the underlying epigenetic and gene-specific mechanisms remain unclear. To explore global hepatic functions of JMJD3, mRNA levels in control and JMJD3-downregulated hepatocytes were compared by RNA-seq analysis. Expression of 2,772 and 2,143 genes was significantly decreased and increased, respectively, over 1.5-fold, by downregulation of JMJD3. ). In gene ontology analysis, genes downregulated with the highest significance were those involved in mitochondrial functions, particularly oxidation/reduction, the respiratory chain, and fatty acid beta-oxidation, Overall, in this study, JMJD3 was shown unexpectedly to be a gene-specific transcriptional partner of SIRT1 and these epigenetic factors interact with the nuclear receptor PPARalpha to epigenetically activate mitochondrial beta-oxidation, but not gluconeogenic, genes during fasting. Liver mRNA profiles were generated by deep sequencing, were profiled in primary mouse hepatocytes in which JMJD3 was downregulated by infection with lentivirus expressing JMJD3 shRNA or by infection with control lentivirus.