Effects of casein kinase 2 interacting protein-1 on the osteogenic differentiation ability of human periodontal ligament stem cells

To investigate the effects of casein kinase 2 interacting protein-1 (CKIP-1) on the osteogenic differentiation ability of human periodontal ligament stem cells (hPDLSCs).

The hPDLSCs were obtained by primary culture with periodontal ligament tissues that were collected from normal humans. Then, a lentiviral vector containing a CKIP-1-specific siRNA sequence was constructed, and the transcriptional level of CKIP-1 in hPDLSCs was downregulated after vector infection. The P4 cells were divided into four groups: the control group, negative control group (infected with a control vector), CKIP-siRNA group (infected by a CKIP-1 siRNA lentivirus) and CKIP-1 group (infected by a CKIP-1 overexpression virus). All of the cells were cultured under osteogenic induction for 21 days. Then, alizarin red staining and quantitative determination were performed to detect the osteogenic differentiation ability of the hPDLSCs. In addition, qPCR was used to detect the transcriptional level of osteogenesis-related regulatory factors, such as Runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP), osteocalcin (OCN), and receptor activator of nuclear factor kappa-B ligand (RANKL), and the osteogenesis-related regulatory factors of the bone morphogenetic protein (BMP) signaling pathway.

There were no differences in the indexes between the negative control group and the control group (P > 0.05). Compared with the negative control group, the CKIP-siRNA group demonstrated more mineralized nodules (P < 0.05), significantly increased calcium salt deposition (P < 0.05), and increased mRNA levels of osteogenesis-related regulatory factors, such as Runx2, ALP, OCN, and RANKL, and the osteogenesis-related regulatory factors of BMP signaling pathway (P < 0.05).

Downregulation of CKIP-1 could promote the osteogenic differentiation of hPDLSCs, which is related to the transcription level of osteogenic-related regulatory factors.