Hpdlfs

Commercially acquired human periodontal ligament fibroblasts (HPdLFs, Lonza, Basel, Switzerland) are pooled from several donors. They were grown in Dulbecco’s modified Eagle medium (DMEM; Thermo Fisher Scientific, Carlsbad, CA, USA) containing 4.5 g/L glucose, 10% heat-inactivated foetal bovine serum (Thermo Fisher Scientific, Carlsbad, CA, USA), 100 U/ml penicillin, 100 µg/ml streptomycin and 50 mg/L L-ascorbic acid at 37°C, 5% CO2, and 95% humidity. When reaching 75% confluency, HPdLFs were passaged with 0.05% Trypsin/EDTA (Thermo Fisher Scientific, Carlsbad, CA, USA). Passage four to eight were used for experimental setups. For transcriptional analysis, HDAC and HAT activity assay as well as CHIP, 2.5 × 10⁴ HPdLFs were seeded into each well of a 6-well plate. For TPH1 adhesion assay, 5 × 10³ HPdLFs were seeded on glass coverslips into each well of a 24-well-plate.
THP1 cells (DMSZ, Braunschweig, Germany) were cultured in RPMI 1640 medium (Thermo Fisher Scientific, Carlsbad, CA, USA) that contains 10% FBS, 100 U/ml penicillin and 100 µg/ml streptomycin at 37°C, 5% CO2 and 95% humidity. Passages were performed weekly and 1 × 10⁶ cells were reseeded into a T175 culture flask (Thermo Fisher Scientific, Carlsbad, CA, USA).