School of Biomedical Engineering, Med-X Research Institute, Shanghai Jiao Tong University, Shanghai, China.
State Key Laboratory of Metal Matrix Composite, National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, Shanghai, China.
Front Immunol. 2019 Dec 3;10:2798. doi: 10.3389/fimmu.2019.02798. eCollection 2019.
Mg-based alloys might be ideal biomaterials in clinical applications owing to favorable mechanical properties, biodegradability, biocompatibility, and especially their anti-inflammatory properties. However, the precise signaling mechanism underlying the inhibition of inflammation by Mg-based alloys has not been elucidated. Here, we investigated the effects of a Mg-2.1Nd-0.2Zn-0.5Zr alloy (denoted as JDBM) on lipopolysaccharide (LPS)-induced macrophages. THP-1 cell-derived macrophages were cultured on JDBM, Ti-6Al-4V alloy (Ti), 15% extract of JDBM, and 7.5 mM of MgCl for 1 h before the addition of LPS for an indicated time; the experiments included negative and positive controls. Our results showed JDBM, extract, and MgCl could decrease LPS-induced tumor necrosis factor (TNF) and interleukin (IL)-6 expression. However, there were no morphologic changes in macrophages on Ti or JDBM. Mechanically, extract and MgCl downregulated the expression of toll-like receptor (TLR)-4 and MYD88 compared with the positive control and inhibited LPS-induced nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways by inactivation of the phosphorylation of IKK-α/β, IKβ-α, P65, P38, and JNK. Additionally, the LPS-induced reactive oxygen species (ROS) expression was also decreased by extract and MgCl. Interestingly, the expression of LPS-induced TNF and IL-6 could be recovered by knocking down TRPM7 of macrophages, in the presence of extract or MgCl. Mechanically, the activities of AKT and AKT1 were increased by extract or MgCl with LPS and were blocked by a PI3K inhibitor, whereas siRNA TRPM7 inhibited only AKT1. Together, our results demonstrated the degradation products of Mg-based alloy, especially magnesium, and resolved inflammation by activation of the TRPM7-PI3K-AKT1 signaling pathway, which may be a potential advantage or target to promote biodegradable Mg-based alloy applications.
镁基合金由于其优异的机械性能、生物降解性、生物相容性，特别是其抗炎特性，可能成为临床应用中的理想生物材料。然而，镁基合金抑制炎症的确切信号机制尚未阐明。在这里，我们研究了 Mg-2.1Nd-0.2Zn-0.5Zr 合金（记为 JDBM）对脂多糖（LPS）诱导的巨噬细胞的影响。THP-1 细胞来源的巨噬细胞在加入 LPS 前 1 小时在 JDBM、Ti-6Al-4V 合金（Ti）、JDBM 的 15%提取物和 7.5mM 的 MgCl 上培养;实验包括阴性和阳性对照。结果表明，JDBM、提取物和 MgCl 均可降低 LPS 诱导的肿瘤坏死因子（TNF）和白细胞介素（IL）-6 的表达。然而，Ti 或 JDBM 上的巨噬细胞形态没有变化。在机制上，与阳性对照相比，提取物和 MgCl 下调了 Toll 样受体（TLR）-4 和 MYD88 的表达，并通过抑制 IKK-α/β、IKβ-α、P65、P38 和 JNK 的磷酸化抑制了 LPS 诱导的核因子-kappa B（NF-κB）和丝裂原活化蛋白激酶（MAPK）信号通路。此外，提取物和 MgCl 还降低了 LPS 诱导的活性氧（ROS）的表达。有趣的是，在存在提取物或 MgCl 的情况下，敲低巨噬细胞中的 TRPM7 可以恢复 LPS 诱导的 TNF 和 IL-6 的表达。在机制上，提取物或 MgCl 与 LPS 一起增加了 AKT 和 AKT1 的活性，而 PI3K 抑制剂阻断了这种作用，而 siRNA TRPM7 仅抑制了 AKT1。综上所述，我们的研究结果表明镁基合金的降解产物，特别是镁，通过激活 TRPM7-PI3K-AKT1 信号通路来缓解炎症，这可能是促进可生物降解镁基合金应用的一个潜在优势或靶点。
