Depletion of HOXA5 inhibits the osteogenic differentiation and proliferation potential of stem cells from the apical papilla.

Mesenchymal stem cells (MSCs) are a prospective cell source for tissue regeneration due to their self-renewal abilities and potential to differentiate into different cell lineages, but the molecular mechanisms of the directed differentiation and proliferation are still unknown. Recently, multiple studies have indicated the crucial role of HOX genes in MSC differentiation and proliferation. However, the role of HOXA5 in MSCs remains unknown. Here, we investigated HOXA5 function in stem cells from the apical papilla (SCAPs). After HOXA5 depletion, the results showed a significant decrease in ALP activity and a weakened mineralization ability of SCAPs. The real-time RT-PCR results showed prominently lessened expression of OPN and BSP. The CCK8 and CFSE results displayed inhibited proliferation of SCAPs, and flow cytometry assays revealed arrested cell cycle progression at the S phase. Furthermore, we found that depletion of HOXA5 upregulated p16INK4A and p18INK4C and downregulated the Cyclin A. Our research demonstrated that depletion of HOXA5 inhibited osteogenic differentiation and repressed cell proliferation by arresting cell cycle progression at the S phase via p16INK4A, p18INK4C and Cyclin A in SCAPs, indicating that HOXA5 has a significant role in maintaining the proliferation and differentiation potential of dental-tissue-derived MSCs.