The mechanical regulatory role of ATP13a3 in osteogenic differentiation of pre-osteoblasts.

ABSTRACT

PURPOSE: The process of osteogenic differentiation hinges upon the pivotal role of mechanical signals. Previous studies found that mechanical tensile strain of 2,500 microstrain (µÎµ) at a frequency of 0.5 Hz promoted osteogenesis in vitro. However, the mechanism of the mechanical strain influencing osteogenesis at the cellular and molecular levels are not yet fully understood. This study aimed to explore the mechanism of mechanical strain on osteogenic differentiation of MC3T3-E1 cells. MATERIALS AND METHODS: Proteomics analysis was conducted to explore the mechanical strain that significantly impacted the protein expression. Bioinformatics identified important mechanosensitive proteins and the expression of genes was investigated using real-time PCR. The dual-luciferase assay revealed the relationship between the miRNA and its target gene. Overexpression and downexpression of the gene, to explore its role in mechanically induced osteogenic differentiation and transcriptomics, revealed further mechanisms in this process. RESULTS: Proteomics and bioinformatics identified an important mechanosensitive lowexpression protein ATP13A3, and the expression of Atp13a3 gene was also reduced. The dual-luciferase assay revealed that microRNA-3070-3p (miR-3070-3p) targeted the Atp13a3 gene. Furthermore, the downexpression of Atp13a3 promoted the expression levels of osteogenic differentiation-related genes and proteins, and this process was probably mediated by the tumor necrosis factor (TNF) signaling pathway. CONCLUSION: Atp13a3 responded to mechanical tensile strain to regulate osteogenic differentiation, and the TNF signaling pathway regulated by Atp13a3 was probably involved in this process. These novel insights suggested that Atp13a3 was probably a potential osteogenesis and bone formation regulator.