An insight into the role of magnesium in the immunomodulatory properties of mesenchymal stem cells

Magnesium (Mg2+) is a mineral with the ability to influence cell proliferation and to modulate inflammatory/immune responses, due to its anti-inflammatory properties. In addition, mesenchymal stem cells (MSCs) modulate the function of all major immune cell populations. Knowing that, the current work aimed to investigate the effects of Mg2+ enrichment, and its influence on the immunomodulatory capacity of MSCs. Murine C3H/10T1/2 MSCs were cultivated in media with different concentrations of Mg2+ (0, 1, 3 and 5 mM), in order to evaluate the effects of Mg2+ on MSC immunomodulatory properties, cell proliferation rates, expression of NFκB and STAT-3, production of IL-1β, IL-6, TGF-β, IL-10, PGE2 and NO, and TRPM7 expression. The results showed that TRPM7 is expressed in MSCs, but Mg2+, in the way that cells were cultivated, did not affect TRPM7 expression. Additionally, there was no difference in the intracellular concentration of Mg2+. Mg2+, especially at 5 mM, raised proliferation rates of MSCs, and modulated immune responses by decreasing levels of IL-1β and IL-6, and by increasing levels of IL-10 and PGE2 in cells stimulated with LPS or TNF-α. In addition, MSCs cultured in 5 mM Mg2+ expressed lower levels of pNFκB/NFκB and higher levels of pSTAT-3/STAT-3. Furthermore, conditioned media from MSCs reduced lymphocyte and macrophage proliferation, but Mg2+ did not affect this parameter. In addition, conditioned media from MSCs cultured at 5 mM of Mg2+ modulated the production profile of cytokines, especially of IL-1β and IL-6 in macrophages. In conclusion, Mg2+ is able to modulate some immunoregulatory properties of MSCs.