Magnesium promotes osteogenesis via increasing OPN expression and activating CaM/CaMKIV/CREB1 pathway

Abstract

Magnesium (Mg) based alloy has been used as a biodegradable implant for fracture repair with considerable efficacy, and it has been proved that magnesium ion (Mg2+), one of the degradation products, could stimulate osteogenesis. Here, we investigated the osteogenesis property of magnesium both in vitro and in vivo, and to identify the cellular and molecular mechanisms that mediate these effects. Results showed that magnesium exerts a dose‐dependent increase in the proliferation of MC3T3 and MG63 cells, and in the expression of osteopontin (OPN), a promising biomarker of osteogenesis. Subsequently, the protein–protein interaction (PPI) network analysis showed the interactions between calmodulin (CaM) and calmodulin‐dependent protein kinase (CaMK) and CREB1. The ratio of p‐CaMKIV/CaMKIV and p‐CREB1/CREB were increased at protein level in MC3T3 and MG63 cells after treatment with Mg2+. Dual‐luciferase reporter gene assay showed that p‐CREB1 could directly bind to OPN promoter and up‐regulate the transcription of OPN after nuclear entry. Meanwhile, the expression of OPN and p‐CREB1, which increased after Mg2+ treatment, was down‐regulated by sh‐CaMKIV or sh‐CREB1. Moreover, the mineralized deposit and expression of OPN were reduced after treatment with an inhibitor of CaMKIV, KN93. In addition, massive cavities in the cortical bone around the Mg screw were showed in vivo after injection of KN93. These data indicated that the osteogenic effect of Mg is related to the activation OPN through CaM/CaMKIV/CREB1 signaling pathway.

Collaborative Design of MgO/FeOx Nanosheets on Titanium: Combining Therapy with Regeneration

“…[ 46,47 ] Moreover, Mg ions could promote osteogenesis directly by upregulating OPN expression through activating CaM/CaMKIV/CREB1 signaling pathway. [ 48 ] In the other hand, an alkaline microenvironment is beneficial for ALP activity and the deposition of hydroxyapatite. [ 19,49 ] The above two positive factors are fulfilled by this study.…”

Alkaline earth metals for osteogenic scaffolds: From mechanisms to applications

“…The osteogenic properties of Mg 2+ and cellular and molecular pathways mediated by Mg 2+ have been extensively studied. 7,[44][45][46] As concluded by Castiglioni et al, 47 a deficit of magnesium ions in the blood, that is, hypomagnesemia, may act as a trigger for osteoporosis by the following mechanisms: (i) alter the structure of apatite crystals and affect bone cells; (ii) decrease parathyroid hormone (PTH) levels, facilitate end-organ resistance to PTH, and cause vitamin D deficiency;…”

“…Furthermore, Mg 2+ could enhance the osteogenic differentiation of BMSCs by activating ERK/MAPK pathway. 54 It has been indicated that the activation of OPN through the CaM/CaMKIV/CREB1 signaling pathway is related to Mg 2+ , providing mechanistic insights into the osteogenic effect of Mg. 45 For osteoblasts, the Transient receptor potential melastatin 7/phosphoinositide 3-kinase (TRPM7/PI3K) signaling pathway and alkaline phosphatase (ALP) have essential roles in osteogenesis. TRPM7, a member of the TRP protein family, is both an Mg 2+ transporter and a protein kinase that regulates cell proliferation and motility.…”

“…Mg plays a regulatory role in the entire bone formation process, and its concentration in serum significantly impacts bone metabolism. The osteogenic properties of Mg 2+ and cellular and molecular pathways mediated by Mg 2+ have been extensively studied 7,44–46 . As concluded by Castiglioni et al, 47 a deficit of magnesium ions in the blood, that is, hypomagnesemia, may act as a trigger for osteoporosis by the following mechanisms: (i) alter the structure of apatite crystals and affect bone cells; (ii) decrease parathyroid hormone (PTH) levels, facilitate end‐organ resistance to PTH, and cause vitamin D deficiency; (iii) increase inflammatory cytokines and stimulate bone remodeling and osteoporosis; (iv) promote endothelial dysfunction; (v) lower ability to reduce the acid load in foods.…”

“…Furthermore, Mg 2+ could enhance the osteogenic differentiation of BMSCs by activating ERK/MAPK pathway 54 . It has been indicated that the activation of OPN through the CaM/CaMKIV/CREB1 signaling pathway is related to Mg 2+ , providing mechanistic insights into the osteogenic effect of Mg 45 …”