TGF-β1 Inhibits Osteogenesis via ZBTB16 Regulation in Periodontal Ligament

To elucidate pivotal molecules through which transforming growth factor-β1 (TGF-β1) regulates osteogenesis in human periodontal ligament (PDL) cells.

In vitro, human PDL, pulpal, and gingival cells were obtained from healthy premolars that were extracted for orthodontic treatment. Cells were treated with dexamethasone for differentiation and alkaline phosphatase and alizarin red staining were used for the mineralization assay. In vivo, the upper first molars in rats were mesially moved. Genes were identified by RNA sequencing and bioinformatics analysis. The expression levels and histological localization of TGF-β1 and ZBTB16 were determined by real-time RT-PCR and Western blotting, and immunofluorescence, respectively.

RNA sequencing identified zinc finger and BTB domain-containing protein 16 (ZBTB16) as a key gene involved in dexamethasone-induced osteogenesis in human PDL cells, which exhibited significantly higher alkaline phosphatase activity compared to other cell types. Knockdown of ZBTB16 markedly impaired the osteogenic differentiation of PDL cells. ZBTB16 expression was significantly suppressed by recombinant TGF-β1. While dexamethasone downregulated TGF-β1 expression in human PDL cells, the osteogenic effects of dexamethasone-evidenced by increased alkaline phosphatase activity and mineralization-were attenuated by TGF-β1. In vivo, both ZBTB16 and TGF-β1 were strongly expressed in PDL cells subjected to tension or compression, which are associated with alveolar bone formation and resorption, respectively.

This study suggests that modulating ZBTB16 via TGF-β1 may have therapeutic potential for maintaining periodontal tissue homeostasis.