Department of Clinical Immunology and Rheumatology, Hiroshima University Hospital, Hiroshima, Japan.
Department of Clinical Immunology and Rheumatology, Hiroshima University Hospital, Hiroshima, Japan,
Pathobiology. 2020;87(3):198-207. doi: 10.1159/000506260. Epub 2020 Mar 3.
Activin A is known to be highly expressed in rheumatoid synovium. In the present study, we investigated the effect of inflammatory cytokines on activin A production and its role in rheumatoid inflammation using freshly prepared rheumatoid synovial cells (fresh-RSC).
Fresh-RSC from patients with rheumatoid arthritis were obtained and stimulated with multiple cytokines for activin A production. Gene expression levels of activin A and inflammatory cytokines were determined by quantitative PCR (qPCR) analysis. An enzyme-linked immunosorbent assay (ELISA) was used to measure activin A and CXCL10 in culture supernatants. The osteoclasts generated from human peripheral monocytes by RANKL stimulation were identified by tartrate-resistant acid phosphatase staining and bone resorption assay using Osteo plate. The expression levels of NFATc1 and cathepsin K, critical intracellular proteins for osteoclastogenesis, were determined by Western blotting.
Activin A production in fresh-RSC was markedly enhanced by the synergistic effect of TGF-β1 with inflammatory cytokines, including TNFα, IL-1β, and IL-6. Activin A inhibited TNFα-induced CXCL10, an important chemoattractant for pathogen-activated T cells and monocytes of osteoclast precursors, but it did not affect the expression of inflammatory cytokines and chemokines. In addition, activin A directly inhibited the expression of NFATc1 and cathepsin K, as well as osteoclast formation in human samples.
Our data indicated that TGF-β1 is involved in the expression of activin A at inflamed joints. Activin A mainly exerts an anti-inflammatory action, which prevents joint damage via the regulation of CXCL10 and osteoclastogenesis.
已知激活素 A 在类风湿滑膜中高度表达。本研究采用新鲜制备的类风湿滑膜细胞（fresh-RSC），探讨炎症细胞因子对激活素 A 产生的影响及其在类风湿炎症中的作用。
从类风湿关节炎患者中获取 fresh-RSC，并通过多种细胞因子刺激其产生激活素 A。通过定量 PCR（qPCR）分析测定激活素 A 和炎症细胞因子的基因表达水平。酶联免疫吸附试验（ELISA）用于测定培养上清液中的激活素 A 和 CXCL10。通过抗酒石酸酸性磷酸酶染色和 Osteo 板骨吸收试验鉴定由 RANKL 刺激产生的人外周单核细胞来源的破骨细胞。通过 Western blot 测定破骨细胞生成的关键细胞内蛋白 NFATc1 和组织蛋白酶 K 的表达水平。
TGF-β1 与炎症细胞因子（TNFα、IL-1β 和 IL-6）的协同作用显著增强了 fresh-RSC 中激活素 A 的产生。激活素 A 抑制了 TNFα 诱导的 CXCL10，后者是病原体激活的 T 细胞和破骨细胞前体细胞中单核细胞的重要趋化因子，但不影响炎症细胞因子和趋化因子的表达。此外，激活素 A 直接抑制了 NFATc1 和组织蛋白酶 K 的表达，以及人样本中的破骨细胞形成。
我们的数据表明，TGF-β1 参与了炎症关节中激活素 A 的表达。激活素 A 主要通过调节 CXCL10 和破骨细胞生成发挥抗炎作用，从而防止关节损伤。
