Proliferation and osteogenic differentiation ability of PDLSCs. PDLSCs were cultured on B-dECM, P-dECM or no-ECM. To control the expression of COL4A2 in dECMs, COL4A2 in the P-dECM group was overexpressed via lentivirus-mediated transduction of PDLCs. COL4A2 in the B-dECM group was downregulated via transfection of BMCs with siRNA. (A) Expression levels of COL4A2 in B-dECM and P-dECM determined by Western blotting. (B) Expression of Ki67, Cyclin B1, and Cyclin D1 in PDLSCs cultured on specific dECMs and no-ECM. (C) Alizarin red staining to detect the osteogenic differentiation ability of PDLSCs in five groups. Quantification of positive staining (right panel). (D) ALP activity was assessed to identify the osteogenic differentiation ability of PDLSCs in five groups. Quantification of positive staining (right panel). (E) Western blotting was used to detect the expression of the indicated proteins to assess osteogenic differentiation of PDLSCs cultured on specific dECMs and no-ECM. The data are presented as the means ± SD; n = 5. * P < 0.05, ** P < 0.01 and *** P < 0.001 represent significant differences in the indicated columns (P-dECM and B-dECM) compared with the no-ECM group. ## P < 0.01 and ### P < 0.001 represent significant differences between the P-dECM and B-dECM groups. ++ P < 0.01 and +++ P < 0.001 represent significant differences in the P-dECM or B-dECM group compared with the P-dECM + LV-COL4A2 or B-dECM + COL4A2-siRNA group.