Hanyang University Institute for Rheumatology Research, Seoul, 04763, Republic of Korea.
Department of Translational Medicine, Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul, 04763, Republic of Korea.
Arthritis Res Ther. 2021 Dec 8;23(1):301. doi: 10.1186/s13075-021-02670-0.
WNT16 is critical for bone homeostasis, but the effect of WNT16 in ankylosing spondylitis (AS) is still unknown. Here, we investigated whether WNT16 influences bone formation and pathophysiological changes of AS in an in vitro model.
The bone tissue from the facet joints was obtained from seven disease control and seven AS patients. Primary osteoprogenitor cells of the facet joints were isolated using an outgrowth method. Isolated osteoprogenitor cells from both control and AS tissues were analyzed by microarray, RT-qPCR, immunoblotting, and immunohistochemistry. The bone-forming activity of osteoprogenitor cells was assessed by various in vitro assays. β-galactosidase staining and senescence-associated secretory phenotype (SASP) using RT-qPCR were used to assess cell senescence.
In microarray analysis, WNT16 expression was significantly elevated in AS osteoprogenitor cells compared to the control. We also validated that WNT16 expression was elevated in AS-osteoprogenitor cells and human AS-bone tissues. WNT16 treatment inhibited bone formation in AS-osteoprogenitor cells but not in the control. Intriguingly, AS-osteoprogenitor cells were stained markedly with β-galactosidase for cell senescence in WNT16 treatment. Furthermore, in an HO stress-induced premature senescence condition, WNT16 treatment increased cell senescence in AS-osteoprogenitor cells and WNT16 treatment under the HO stress condition showed an increase in p21 protein and SASP mRNA expression. The WNT16-induced SASP expression in AS-osteoprogenitor cells was reduced in WNT16 knockdown cultures.
WNT16 is highly expressed in AS and WNT16 treatment facilitated cell senescence in AS-osteoprogenitor cells during osteoblast differentiation accompanied by suppression of bone formation. The identified role of WNT16 in AS could influence bone loss in AS patients.
WNT16 对骨稳态至关重要，但 WNT16 在强直性脊柱炎（AS）中的作用尚不清楚。在这里，我们研究了 WNT16 是否会影响体外模型中的骨形成和 AS 的病理生理变化。
从 7 例疾病对照组和 7 例 AS 患者的小关节获得骨组织。采用体外生长法分离小关节原代成骨细胞。通过微阵列、RT-qPCR、免疫印迹和免疫组织化学分析对照组和 AS 组织的分离原代成骨细胞。通过各种体外测定评估成骨细胞的成骨活性。β-半乳糖苷酶染色和衰老相关分泌表型（SASP）通过 RT-qPCR 用于评估细胞衰老。
在微阵列分析中，与对照组相比，AS 成骨细胞中的 WNT16 表达明显升高。我们还验证了 WNT16 在 AS 成骨细胞和人 AS 骨组织中表达升高。WNT16 处理抑制 AS 成骨细胞中的骨形成，但不抑制对照组中的骨形成。有趣的是，WNT16 处理在 AS 成骨细胞中明显染色β-半乳糖苷酶用于细胞衰老。此外，在 HO 应激诱导的过早衰老条件下，WNT16 处理增加 AS 成骨细胞中的细胞衰老，并且在 HO 应激条件下，WNT16 处理增加 p21 蛋白和 SASP mRNA 表达。WNT16 诱导的 AS 成骨细胞中的 SASP 表达在 WNT16 敲低培养物中减少。
WNT16 在 AS 中高度表达，WNT16 处理在成骨细胞分化过程中促进 AS 成骨细胞中的细胞衰老，同时抑制骨形成。鉴定的 WNT16 在 AS 中的作用可能会影响 AS 患者的骨质流失。
