Department of Orthopaedic Surgery, The First People's Hospital of Wenling, Chuan'an Nan Road NO 333, Wenling, 317500, Zhejiang, China.
Department of Orthopaedic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, 215000, Jiangsu, China.
J Orthop Surg Res. 2021 Dec 7;16(1):711. doi: 10.1186/s13018-021-02860-1.
The present study aimed to determine the role of the discoidin domain receptor 2 (DDR2) in the osteonectin (ON) regulation of osteoblast mineralization through the activation of p38 mitogen-activated protein kinase (MAPK).
Four groups were established: the ON group, the inhibitor group, the Ddr2-small interfering ribonucleic acid (siRNA) group, and the control group. Osteoblasts from the parietal bones of neonatal Sprague-Dawley rats were isolated and cultured. In the ON group, 1 µg/mL ON was added to the osteoblasts. The gene expressions of collagen 1 (Col 1) and Ddr2 were detected using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). In the inhibitor group, the osteoblasts were added to WRG-28 (a specific DDR2 inhibitor), and in the Ddr2-siRNA group, the osteoblasts were transfected with Ddr2-siRNA. The gene and protein expressions of DDR2, bone sialoprotein, osteocalcin, osteopontin, and p38 MAPK were determined using RT-qPCR and western blot analysis. Alizarin red staining and transmission electron microscopy were used to detect mineralization.
The results showed that ON enhanced the osteoblast Col 1 and Ddr2 gene expressions, while the use of a Ddr2-siRNA/DDR2-blocker decreased the OPN, BSP, OCN, and P38 gene and protein expressions and reduced osteoblast cellular activity and mineralized nodules.
The present study demonstrated that DDR2 activation of p38 MAPK is an important approach to ON-regulating osteoblast mineralization.
本研究旨在通过激活丝裂原活化蛋白激酶（MAPK）p38 来确定双调蛋白受体 2（DDR2）在骨桥蛋白（ON）调节成骨细胞矿化中的作用。
建立 4 组：ON 组、抑制剂组、DDR2-小干扰 RNA（siRNA）组和对照组。分离培养新生 Sprague-Dawley 大鼠顶骨的成骨细胞。在 ON 组中，将 1μg/mL 的 ON 添加到成骨细胞中。采用反转录定量聚合酶链反应（RT-qPCR）检测胶原 1（Col 1）和 DDR2 的基因表达。在抑制剂组中，向成骨细胞中加入 WRG-28（DDR2 特异性抑制剂），在 DDR2-siRNA 组中，转染 DDR2-siRNA。采用 RT-qPCR 和 Western blot 分析检测 DDR2、骨涎蛋白、骨钙素、骨桥蛋白和 p38 MAPK 的基因和蛋白表达。采用茜素红染色和透射电镜观察矿化情况。
结果表明，ON 增强了成骨细胞 Col 1 和 DDR2 的基因表达，而使用 DDR2-siRNA/DDR2 阻断剂降低了 OPN、BSP、OCN 和 P38 的基因和蛋白表达，并降低了成骨细胞的细胞活性和矿化结节。
本研究表明，DDR2 激活 p38 MAPK 是 ON 调节成骨细胞矿化的重要途径。
