Characterization of osteoprotegerin-induced signaling in human endothelial cells

背景和目的：凝血酶是一种促凝血、促炎分子，也是骨吸收的潜在介质。骨保护素（OPG）是与核因子-κB（NF-κB）配体（RANKL）的受体活化因子结合并抑制破骨细胞分化的关键分子。本研究旨在评价凝血酶对人真皮微血管内皮细胞（HMVEC）生成OPG的生物学效应。材料和方法：用2.1- 11.2U/mL凝血酶处理HMVEC 18 h。酶联免疫吸附试验（ELISA）评估凝血酶诱导的OPG产生。用抑制剂研究凝血酶对HMVEC中OPG产生和凝血酶信号通路的影响。结果：凝血酶诱导HMVEC产生OPG，并呈剂量依赖性。磷脂酰肌醇3-激酶（PI 3 K）抑制剂和Src激酶抑制剂对凝血酶诱导的OPG表达具有抑制作用。凝血酶诱导的OPG产生也被蛋白酶激活受体（PAR）-1拮抗剂抑制。结论：凝血酶可能通过PAR-1诱导HMVEC表达OPG。凝血酶诱导的OPG产生受PI 3 K和Src通路调节。这些结果表明，凝血酶可能在调节血清OPG水平中起重要作用。

Background and Objectives: Thrombin is a procoagulant and proinflammatory molecule that is also a potential mediator of bone resorption . Osteoprotegerin (OPG) is a key molecule that binds to the receptor-activator of the nuclear factor-κB (NF-κB) ligand (RANKL), and inhibits osteoclast differentiation. This study aimed to evaluate the biological effects of thrombin on OPG production in human dermal microvascular endothelial cells (HMVEC). Materials and Methods: HMVEC were treated with 2.1-11.2 U/mL of thrombin for 18 h. Thrombin-induced OPG production was assessed by enzyme-linked immunosorbent assay (ELISA). Inhibitors were used to investigate the influence of thrombin on OPG production in HMVEC and the thrombin-signaling pathway. Results: Thrombin induced OPG production in HMVEC in a dose-dependent manner. The phosphatidylinositol 3-kinase (PI3K) inhibitor and Src kinase inhibitor exerted an inhibitory effect on thrombin-induced OPG expression. Thrombin-induced OPG production was also inhibited by the protease-activated receptor (PAR)-1 antagonist. Conclusion: Thrombin induces OPG expression in HMVEC, possibly through PAR-1. Thrombin-induced OPG production is regulated by the PI3K and Src pathways. These findings suggest that thrombin may play a significant role in regulating the levels of serum OPG.