Magnesium Regulates the Migration and Differentiation of NPMSCs via the Integrin Signaling Pathway

Background: Nucleus pulposus mesenchymal stem cells play a fatal role in intervertebral disc homeostasis. Magnesium is an essential bioactive element for the human body, regulating intracellular enzyme activity and promoting stem cell adhesion and differentiation. Objective: This study aimed to detect the effects of Mg2+ on nucleus pulposus mesenchymal stem cells and explore the mechanism by which magnesium ions promote the differentiation of nucleus pulposus mesenchymal stem cells. Methods: Nucleus pulposus mesenchymal stem cells digested from the caudal intervertebral disc of 3-month-old SD rats were interfered with using different concentrations of magnesium ions, and their levels of migration, adhesion, and differentiation were evaluated by biochemical and molecular indices. Results: Magnesium ion treatment significantly enhanced the migration and adhesion ability of NPMSCs. Meanwhile, magnesium ion treatment promoted NP differentiation of NPMSCs and the formation of nucleus pulposus precipitates. p-Smad2 immunofluorescence staining demonstrated that the nuclear translocation of p-Smad2 was significantly up-regulated after Mg2+ stimulation, while this effect was significantly attenuated by the addition of β1 blocker. In addition, protein quantification experiments demonstrated the same results. These results showed that 10mM magnesium can significantly promote the differentiation of NPMSCs, and its mechanism is related to the integrin receptor and TGF-β signaling pathway. Conclusion: Mg2+ at 10 mM significantly promoted migration and differentiation of NPMSCs by a mechanism related to the integrin-TGF signaling pathway.