转化生长因子-β刺激骨关节炎滑膜中神经生长因子的产生。
Transforming growth factor-β stimulates nerve growth factor production in osteoarthritic synovium.
机构信息
Department of Orthopedic Surgery, Kitasato University School of Medicine, 1-15-1 Minami-ku, Kitasato, Sagamihara City, Kanagawa, 252-0374, Japan.
Department of Biochemistry, Kitasato University School of Medicine, 1-15-1 Minami-ku, Kitasato, Sagamihara City, Kanagawa, 252-0374, Japan.
出版信息
BMC Musculoskelet Disord. 2019 May 10;20(1):204. doi: 10.1186/s12891-019-2595-z.
BACKGROUND
Nerve growth factor (NGF) contributes to pain in knee osteoarthritis (KOA) patients. Transforming growth factor-beta (TGF-β) stimulates NGF expression in chondrocytes from KOA patients. However, the correlation between synovial TGF-β and NGF levels has not been sufficiently studied in human KOA patients. Further, the mechanism governing NGF regulation by TGF-β in synovial cells is unclear.
METHODS
During total knee arthroplasty, we extracted the synovial tissue (SYT) of 107 subjects with unilateral Kellgren/Lawrence grade 3-4 KOA confirmed by radiography. We examined the distribution of TGF-β and NGF using immunohistochemistry, and analyzed the relationship between NGF and TGFB mRNA levels. Cultured synovial cells extracted from SYT were exposed to culture medium (control), human recombinant TGF-β (rhTGF-β), rhTGF-β + ALK5 inhibitor SB505124, rhTGF-β + transforming growth factor activating kinase 1 (TAK1) inhibitor (5Z)-7-oxozeaenol, or rhTGF-β + p38 inhibitor SB203580 for 30 min, 6 h and 24 h. NGF mRNA expressed by the cultured cells and NGF protein levels in the cell supernatant were detected by real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Phosphorylation of p38 was evaluated by western blotting.
RESULTS
NGF mRNA levels were positively correlated with those of TGFB. Cells expressing TGF-β and NGF protein were observed in the lining layer of SYT. TGF-β stimulated increased NGF mRNA expression and NGF protein production. The ALK5 inhibitor completely suppressed the TGF-β-mediated increase in NGF expression and NGF production in synovial cells. ALK5, TAK1 and p38 inhibitors inhibited the TGF-β-induced phosphorylation of p38, and TAK1 and p38 inhibitors partially inhibited the TGF-β-mediated increase in NGF expression and NGF production in synovial cells.
CONCLUSION
TGF-β regulates NGF production via the TGF-β/ALK5 signaling pathway in osteoarthritic synovium. This effect may partially occur through inhibition of the TAK1/p38 pathway in the SYT of KOA patients.
背景
神经生长因子（NGF）参与膝骨关节炎（KOA）患者的疼痛。转化生长因子-β（TGF-β）刺激 KOA 患者软骨细胞中 NGF 的表达。然而，人类 KOA 患者滑膜 TGF-β和 NGF 水平之间的相关性尚未得到充分研究。此外，TGF-β在滑膜细胞中调节 NGF 的机制尚不清楚。
方法
在全膝关节置换术中，我们从 107 名单侧影像学证实为 Kellgren/Lawrence 3-4 级 KOA 的患者的滑膜组织（SYT）中提取了滑膜组织（SYT）。我们使用免疫组织化学检查了 TGF-β和 NGF 的分布，并分析了 NGF 与 TGFB mRNA 水平之间的关系。从 SYT 中提取的培养滑膜细胞暴露于培养基（对照）、人重组 TGF-β（rhTGF-β）、rhTGF-β+ALK5 抑制剂 SB505124、rhTGF-β+转化生长因子激活激酶 1（TAK1）抑制剂（5Z）-7-氧杂泽诺醇或 rhTGF-β+p38 抑制剂 SB203580 30min、6h 和 24h。通过实时聚合酶链反应（PCR）和酶联免疫吸附测定（ELISA）分别检测培养细胞中表达的 NGF mRNA 和细胞上清液中的 NGF 蛋白水平。通过 Western blot 评估 p38 的磷酸化。
结果
NGF mRNA 水平与 TGFB 水平呈正相关。在 SYT 的衬里层观察到表达 TGF-β和 NGF 蛋白的细胞。TGF-β 刺激 NGF mRNA 表达和 NGF 蛋白产生增加。ALK5 抑制剂完全抑制了 TGF-β 介导的滑膜细胞中 NGF 表达和 NGF 产生的增加。ALK5、TAK1 和 p38 抑制剂抑制 TGF-β 诱导的 p38 磷酸化，TAK1 和 p38 抑制剂部分抑制 TGF-β 介导的滑膜细胞中 NGF 表达和 NGF 产生的增加。
结论
TGF-β 通过 TGF-β/ALK5 信号通路在骨关节炎滑膜中调节 NGF 的产生。这种作用可能部分通过抑制 KOA 患者 SYT 中的 TAK1/p38 途径发生。
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