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

Magnesium (Mg) 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 Mg enrichment, and its influence on the immunomodulatory capacity of MSCs. Murine C3H/10T1/2 MSCs were cultivated in media with different concentrations of Mg (0, 1, 3 and 5 mM), in order to evaluate the effects of Mg 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 Mg, in the way that cells were cultivated, did not affect TRPM7 expression. Additionally, there was no difference in the intracellular concentration of Mg. Mg, 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 Mg 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 Mg did not affect this parameter. In addition, conditioned media from MSCs cultured at 5 mM of Mg modulated the production profile of cytokines, especially of IL-1β and IL-6 in macrophages. In conclusion, Mg is able to modulate some immunoregulatory properties of MSCs.