Inhibition assays with antibody against tumor necrosis factor-receptor 1 (TNFR1
). (A) Analysis of nuclear factor-kappa-B (NF-κB) phosphorylation upon blockade of TNFR1. Dental pulp stems (DPCs) were incubated with different concentrations (0, 4, 6, and 10 μg/mL) of TNFR1AB for 1 hour prior to treatment with TNF-α (10 ng/mL). Phosphorylation of NF-κB (p65, p105) was examined by Western blot at 5 minutes after stimulation. TNFR1AB inhibited TNF-α-induced phosphorylation of p105 and p65 in a dose-dependent manner, and a maximum effect was observed with a concentration of 10 μg/mL. (B) Flow cytometric analysis of expression of stage-specific embryonic antigen 4 (SSEA-4). TNFR1AB only partially inhibited TNF-α-induced increase in the number of SSEA-4+ cells. (C) Analysis of mRNA levels of OCT-4 and NANOG upon inhibition of TNFR1. Although TNF-α treatment increased the gene expression of OCT-4 and NANOG, TNFR1AB nullified the TNF-α-induced increase OCT-4 mRNA levels only. **P <0.01, one-way analysis of variance (ANOVA), Tukey test. Data are representative of at least three different experiments.