Retinol/inflammation affect stemness and differentiation potential of gingival stem/progenitor cells via Wnt/β‐catenin

Background and objective Inflammatory cytokines impact the course of periodontal disease, repair, and regeneration. Vitamin A and its metabolites are inflammation‐modulatory biomolecules, affecting cellular pluripotency. The aim of this study was to investigate the effect of retinol and periodontal inflammatory cytokines (IL‐1β/TNF‐α/IFN‐γ) on pluripotency and proliferative properties of gingival mesenchymal stem/progenitor cells (G‐MSCs), for the first time. Material and methods Human G‐MSCs (n = 5) were STRO‐1 immuno‐magnetically sorted, characterized and expanded in basic medium (control group), in basic medium with IL‐1β (1 ng/mL), TNF‐α (10 ng/mL), and IFN‐γ (100 ng/mL) (inflammatory group), in basic medium with retinol (20 μmol/L) (retinol group) and with retinol added to the inflammatory group (inflammatory/retinol group). β‐catenin levels at 1 hour, cellular proliferation over 14 days, and colony‐forming units (CFUs) at 14 days were investigated. Pluripotency gene expressions were examined at 1, 3, and 5 days via reverse transcription‐polymerase chain reaction (RT‐PCR). Multilineage differentiation potential was evaluated, following 5 days priming, using qualitative and quantitative histochemistry and RT‐PCR. Results G‐MSCs were CD14 − , CD34 − , CD45 − , CD73 + , CD90 + , CD105 + , and showed mesenchymal stem/progenitor cells’ hallmarks, CFUs, and multilineage differentiation potential. Intracellular β‐catenin significantly declined in the stimulated groups ( P  < 0.001, Friedman test). Cellular proliferation at 72 hours was most prominent in the control and inflammatory group [Median cell numbers (Q25/Q75); 6806 (4983/7312) and 5414 (4457/7230), respectively], followed by an upsurge in the retinol group. At 14 days, the retinol group exhibited the highest CFUs [Median CFUs (Q25/Q75); 35 (20/58), P  = 0.043, Wilcoxon signed‐rank]. Nanog was most expressed in the inflammatory and retinol group [Median gene expression/PGK1 (Q25/Q75); 0.0006 (0.0002/0.0014) and 0.0005 (0.0003/0.0008)]. Inflammation significantly upregulated Sox2 expression [0.0002 (0.0008/0.0005)], while its expression was diminished in the retinol and inflammatory/retinol group ( P  < 0.001, Friedman test). Inflammatory/retinol group exhibited the highest multilineage differentiation potential. Conclusion Controlled short‐term inflammatory/retinol stimuli activate the Wnt/β‐catenin pathway, affecting G‐MSCs’ pluripotency, proliferation, and differentiation. The present findings provide further insights into the inflammatory‐regenerative interactions and their modulation potential for G‐MSCs‐mediated periodontal repair/regeneration.