Kaempferol antagonizes adipogenesis by repressing histone H3K4 methylation at PPARγ target genes

We previously demonstrated that kaempferol, a flavonoid present in various herbs, inhibits adipogenesis by repressing peroxisome proliferator-activated receptor γ (PPARγ) activity. Here, we focused on elucidation of the underlying mechanism using genome-wide tools. First, RNA sequencing (RNA-seq) analysis showed downregulation of genes involved in adipogenesis in response to kaempferol. Subsequent ChIP assays revealed that kaempferol regulates the expression of adipogenic (Adipoq, Fabp4, Lpl) genes by modulating enrichment of active H3K4me3 and repressive H3K27me3 histone codes on target promoters. Second, we performed ChIP sequencing analysis of active H3K4me3, and co-analysis with RNA-seq identified PPARγ responsive sites in genes downregulated by kaempferol, in terms of expression and H3K4me3 deposition. Third, direct kaempferol binding to PPARγ, for which the K_D value was 44.54 μM, was determined by microscale thermophoresis. Further RT-qPCR and GST pull-down assays demonstrated that kaempferol antagonizes rosiglitazone-induced PPARγ activation and impairs the rosiglitazone-dependent interaction between PPARγ and its coactivator CBP. Overall, our data suggest that kaempferol, as a PPARγ antagonist, mediates epigenetic repression of lipid accumulation by regulating histone methylation, and could serve as a candidate epigenetic drug to treat obesity-related diseases.