Inflammatory Stress Impairs Dental Pulp Stem Cell Osteogenic Function Through ZDHHC16-Related Redox Dysregulation

Introduction and aims Dental pulp stem cells (DPSCs) are a candidate cell source for regenerative dental applications, but inflammatory stress can impair their osteogenic function. This study examined whether zinc finger DHHC-type palmitoyltransferase 16 (ZDHHC16) is associated with impaired osteogenic behaviour in Porphyromonas gingivalis lipopolysaccharide (Pg-LPS)-treated DPSCs and whether cAMP response element-binding protein (CREB)-related redox and S-palmitoylation changes accompany this process. Methods A Pg-LPS challenge model was established in mouse DPSCs, followed by ZDHHC16 overexpression or silencing. Oxidative stress, mitochondrial injury, cell damage and intracellular iron were assessed. CREB phosphorylation and apurinic/apyrimidinic endonuclease 1 (APE1) and nuclear factor erythroid 2-related factor 2 (Nrf2) expression were evaluated by western blotting and immunofluorescence and CREB/APE1 S-palmitoylation was assessed by acyl-biotin exchange. Pharmacological CREB modulation was used to assess functional involvement. Metabolic activity, scratch-wound closure and osteogenic differentiation were also evaluated. Results ZDHHC16 overexpression aggravated oxidative stress, mitochondrial injury and cell damage readouts in Pg-LPS-treated DPSCs, whereas ZDHHC16 knockdown showed the opposite pattern. ZDHHC16 dysregulation was accompanied by corresponding changes in CREB and APE1 S-palmitoylation, the p-CREB/total CREB ratio and APE1/Nrf2 expression. Pharmacological CREB modulation partly modified the associated redox and osteogenic phenotypes. ZDHHC16 overexpression was also associated with reduced metabolic activity, impaired scratch-wound closure and suppressed osteogenic differentiation, with opposite effects after knockdown. Conclusion ZDHHC16 dysregulation is associated with impaired osteogenic function of Pg-LPS-treated DPSCs, together with oxidative and mitochondrial injury and altered CREB/APE1 S-palmitoylation and CREB-related redox signalling. Clinical relevance ZDHHC16-associated intracellular stress regulation may contribute to the loss of DPSC osteogenic competence under inflammatory conditions and may inform future regenerative strategies in inflammation-affected settings.