Magnesium Compounds Increase Aquaporin-3 in Human Epidermal Keratinocyte HaCaT Cells

Several studies have shown that magnesium can be a useful tool in preventing various skin disorders. However, the mechanism remains unclear. In this study, we analyzed the mechanism by which magnesium improves skin function, focusing on the water channel aquaporin-3 (AQP3), which is a cutaneous functional molecule. Magnesium compounds (magnesium acetate, magnesium chloride, magnesium sulfate, and magnesium lactate) were added to human epidermal keratinocyte HaCaT cells, and the mRNA and protein expression levels of AQP3 were analyzed. We also investigated the mechanism by which magnesium acetate regulates AQP3 expression. Several magnesium compounds were individually added to HaCaT cells, and 6 hours later, the AQP3 mRNA expression level in the treated cells was significantly increased compared to that in the control cells. Among the magnesium compounds, magnesium acetate had a strong effect and markedly increased the AQP3 mRNA expression level by approximately 3.5 times and the protein expression level by approximately 3 times. Magnesium acetate also enhanced the phosphorylation of cAMP response element-binding protein (CREB), which is involved in AQP3 transcription. Furthermore, the increase in AQP3 expression levels induced by magnesium acetate was suppressed by treatment with the protein kinase A (PKA) inhibitor H-89. Magnesium compounds increased the expression level of AQP3 in epidermal keratinocytes and may have a skin-moisturizing effect. The magnesium-induced phosphorylation of CREB may be associated with the activation of the cAMP/PKA pathway. Overall, magnesium compounds may be useful for the prevention and treatment of age-associated xeroderma.