Trichostatin A-Induced H3K9ac Hyperacetylation Selectively Enriches Promoters in Adipogenic Human Periodontal Ligament Stem Cells

Adipogenesis is regulated by histone modifications associated with chromatin accessibility. These modifications include histone H3 lysine 9 acetylation (H3K9ac), a mark linked to transcriptional activation. Its dynamics are governed by histone acetyltransferases and histone deacetylases (HDACs). Although trichostatin A (TSA) induces global hyperacetylation, its association with the differential enrichment of H3K9ac at regulatory elements during adipogenesis in human cells remains unclear. Therefore, this study characterized the genomic distribution of TSA-induced H3K9ac enrichment in human periodontal ligament stem cells (hPDLSCs). To this end, hPDLSCs underwent adipogenic differentiation for 14 days following TSA pretreatment (100 nM, 72 h). Cell morphology, lipid droplet radius, and the nuclear distribution of H3K9ac and H3K9me2 were evaluated by immunofluorescence, while the genomic distribution of H3K9ac was assessed by ChIP-seq. Statistical significance was assessed using an unpaired two-tailed Student’s t-test (p < 0.05) and MACS3 peak calling (q = 0.001). TSA reduced the lipid droplet radius by 1.69-fold and increased the nuclear H3K9ac signal by 10.17-fold, while reducing H3K9me2 signal by 1.38-fold. Furthermore, 752 promoters exhibited greater H3K9ac enrichment under TSA treatment compared with 364 in the control, including genes associated with adipogenesis, such as PPARGC1B and AGPAT2, and chromatin remodeling genes SETD5 and KDM2A. Overall, these findings indicate that TSA alters the adipogenic phenotype and increases H3K9ac enrichment at promoters associated with metabolic and chromatin remodeling programs.