High concentration magnesium inhibits extracellular matrix calcification and protects articular cartilage via Erk/autophagy pathway

Abstract

The significant cytopathological changes of osteoarthritis are chondrocyte hypertrophy, proteoglycan loss, extracellular matrix (ECM) calcification, and terminally, the replacement of cartilage by bone. Meanwhile, magnesium ion (Mg 2+ ), as the second most abundant divalent cation in the human body, has been proved to inhibit the ECM calcification of hBMSCs (human bone marrow stromal cells), hVSMCs (Human vascular smooth muscle cells), and TDSCs (tendon-derived stem cells) in vitro studies. The ATDC5 cell line, which holds chondrocyte characteristics, was used in this study as an in vitro subject. We found that Mg 2+ can efficiently suppress the ECM calcification and downregulate both hypertrophy and matrix metalloproteinase-related genes. Meanwhile, Mg 2+ inhibits the formation of autophagy by inhibiting Erk phosphorylation signaling and lowers the expression of LC3, and eventually effectively reduces the formation of ECM calcification in vitro. In this study, we also used destabilization of the medial meniscus (DMM)-induced osteoarthritis (OA) animal model to further confirm the protective effect of Mg 2+ on articular cartilage. Compared with the control group (saline-injected), continuous intraarticular magnesium chloride (MgCl 2 ) injection can significantly alleviate the severity of cartilage calcification in OA animal model. Immunofluorescence staining also revealed that saline-injected DMM group had a higher positive rate of LC3 expression in cartilage chondrocytes, compared with MgCl 2 -injected DMM group. In general, Mg 2+ can significantly downregulate the hypertrophic gene Runx2, MMP13, and Col10α1, upregulate the chondrogenic genes Sox9 and Col1α1, inhibit the Erk phosphorylation signaling, reduce the expression of autophagy protein LC3, and effectively inhibit the ECM calcification of ATDC5. In vivo study also proved that intra-articular injection of Mg 2+ protected knee cartilage by inhibiting the autophagy formation. K E Y W O R D S autophagy, calcification inhibitive, chondrocyte hypertrophy, DMM-induced osteoarthritis, magnesium ion SUPPORTING INFORMATION Additional supporting information may be found online in the Supporting Information section. How to cite this article: Yue J, Jin S, Gu S, Sun R, Liang Q. High concentration magnesium inhibits extracellular matrix calcification and protects articular cartilage via Erk/ autophagy pathway.

MicroRNA-16, via FGF2 Regulation of the ERK/MAPK Pathway, Is Involved in the Magnesium-Promoted Osteogenic Differentiation of Mesenchymal Stem Cells

“…Male 3-week-old Sprague-Dawley rats were purchased from the Experimental Animal Center of Nanjing Medical University. Primary BMSCs were isolated and characterized as described previously [26,27]. Under sterile conditions, BMSCs were collected by flushing the femurs and tibias with alpha minimal essential medium (αMEM; Sigma-Aldrich CO, St. Louis, MO, USA) containing fetal bovine serum (FBS, 15%; Lonza Inc., Walkersville, MD, USA), ultraglutamine (1%, Lonza), penicillin (100 U/mL), and streptomycin (100 μg/mL).…”

“…In addition to their effects on bone formation, Mg ions at optimal concentrations enhance the phenotype of chondrocytes [46], and magnesium deficiency elevates the numbers of adipocytes [47]. High concentrations of magnesium inhibit calcification of the extracellular matrix and protect articular cartilage via the Erk/autophagy pathway [27].…”

Intra-articular Magnesium to Alleviate Postoperative Pain After Arthroscopic Knee Surgery: A Meta-analysis of Randomized Controlled Trials

“…Mg deficiency in the extracellular matrix of cartilage may lead to typical joint cartilage lesions [42]. In contrast, high concentrations of IA Mg can signi cantly inhibit extracellular matrix calci cation and protect articular cartilage [44,45]. Similarly, clinical trials have found that subjects with lower levels of serum Mg had a higher prevalence of knee chondrocalcinosis [46].…”

Intra-articular Magnesium to Alleviate Postoperative Pain After Arthroscopic Knee Surgery: A Meta-analysis of Randomized Controlled Trials

“…Additionally, animal experiments suggest that Mg de ciency in the extracellular matrix of cartilage may lead to typical joint cartilage lesions [43]. In contrast, high concentrations of IA Mg can signi cantly inhibit extracellular matrix calci cation and protect articular cartilage [44,45]. Similarly, clinical trials have found that subjects with lower levels of serum Mg had a higher prevalence of knee chondrocalcinosis [46].…”