Objective To investigate the crosstalk between canonical Wnt/β-catenin and noncanonical Wnt/Ca2+ pathway in osteoblast differentiation process of periodontal ligament stem cell (PDLSC) in inflammatory microenvironments.Methods PDLSCs were obtained from human healthy individuals(H-PDLSC) and patients with periodontitis(P-PDLSC).The H/P-PDLSCs were transfected with β-catenin siRNA.Cell morphology was observed under fluorescent microscope and transfection efficiency was easured by Western blotting after transfection of PDLSC.The mRNA expressions of Runt-related transcription factor 2(Runx2),β-catenin and nemo like kinase(NLK) were detected by real time PCR,the protein expressions of calciun/calmodulin-dependent protein kinase Ⅱ (CaMK Ⅱ) and NLK were examined by Western blotting and the CaMK Ⅱ was observed by immunofluorescence staining,respectively.Results The β-catenin expressions in H/P-PDLSCs were inhibited specifically and efficiently by treatment of β-catenin-siRNA for 24 h.After a 3-day-osteogenic process,results of real-time quantitative PCR showed that the Runx2 mRNA expression in P-PDLSC siRNA β-catenin transfected group(4.553 ± 0.659) was significantly higher than that in P-PDLSC empty plasmid control group(l.918 ±0.315)(P=0.000).A similar trend was observed in the NLK mRNA expression tests(7.341 ± 1.331 vs.5.664 ± 0.792)(P=0.030).Accordingly,the protein expression levels of CaMK Ⅱ,NLK were higher in P-PDLSC siRNA β-catenin transfected group than that in P-PDLSC empty plasmid control group in osteogenic differentiation condition for 3 days.CaMK Ⅱ was more strongly induced in P-PDLSC siRNA β-catenin group than that in P-PDLSC empty plasmid control group after PDLSC cultured in osteogenic medium for 3 days.Conclusions Both canonical Wnt/β-catenin and noncanonical Wnt/Ca2+ pathway could regulate the osteogenic differentiation potential of P-PDLSC.Suppression of β-catenin by siRNA promoted osteogenic differentiation via increasing noncanonical Wnt signaling pathway of PDLSC in inflammatory microenvironments.