Zinc finger protein 750 is a novel regulator of osteoblast differentiation and bone homeostasis by transcriptionally deactivating SNAI1 signaling

Zinc finger protein 750 (ZNF750) has been identified as a potential tumor suppressor across multiple malignancies. Nevertheless, the specific involvement of ZNF750 in the regulation of mesenchymal cell differentiation and bone homeostasis has yet to be elucidated. In the current study, we observed a substantial presence of ZNF750 in bone tissue and noted alterations in its expression during osteogenic differentiation of mesenchymal progenitor cells. Functional experiments indicated that ZNF750 promoted osteogenic differentiation while impeding adipogenic differentiation from mesenchymal stem/progenitor cells. Further mechanistic investigations revealed that ZNF750 transcriptionally suppressed the expression of Snail family transcriptional repressor 1 (SNAI1) by binding to the proximal promoter region of Snai1 gene, thereby activating Wnt/β-catenin signaling. SNAI1 exerted opposing effects on cell differentiation towards osteoblasts and adipocytes in comparison to ZNF750. The overexpression of SNAI1 counteracted the dysregulated osteogenic and adipogenic differentiation induced by ZNF750. Furthermore, the transplantation of Znf750-silenced bone marrow stromal cells into the marrow of wild-type mice resulted in a reduction in cancellous and cortical bone mass, alongside a decrease in osteoblasts and an increase in marrow adipocytes, while the number of osteoclasts remained unchanged. This study presents the first demonstration that ZNF750 regulates the differentiation of osteoblasts and adipocytes from mesenchymal stem/progenitor cells by transcriptionally deactivating SNAI1 signaling, thereby contributing to the maintenance of bone homeostasis. It suggests that ZNF750 may represent a promising therapeutic target for metabolic bone disorders such as osteoporosis.