Development and Regeneration, Skeletal Biology and Engineering Research Center, Laboratory of Tissue Homeostasis and Disease, KU Leuven, Leuven, Belgium.
Development and Regeneration, Skeletal Biology and Engineering Research Center, Laboratory of Tissue Homeostasis and Disease, KU Leuven, Leuven, Belgium
Ann Rheum Dis. 2023 Jul;82(7):963-973. doi: 10.1136/ard-2022-223789. Epub 2023 Mar 16.
In osteoarthritis, methylation of lysine 79 on histone H3 (H3K79me), a protective epigenetic mechanism, is reduced. Histone methylation levels are dynamically regulated by histone methyltransferases and demethylases. Here, we aimed to identify which histone demethylases regulate H3K79me in cartilage and investigate whether their targeting protects against osteoarthritis.
We determined histone demethylase expression in human non-osteoarthritis and osteoarthritis cartilage using qPCR. The role of histone demethylase families and subfamilies on H3K79me was interrogated by treatment of human C28/I2 chondrocytes with pharmacological inhibitors, followed by western blot and immunofluorescence. We performed C28/I2 micromasses to evaluate effects on glycosaminoglycans by Alcian blue staining. Changes in H3K79me after destabilisation of the medial meniscus (DMM) in mice were determined by immunohistochemistry. Daminozide, a KDM2/7 subfamily inhibitor, was intra-articularly injected in mice upon DMM. Histone demethylases targeted by daminozide were individually silenced in chondrocytes to dissect their role on H3K79me and osteoarthritis.
We documented the expression signature of histone demethylases in human non-osteoarthritis and osteoarthritis articular cartilage. Inhibition of Jumonji-C demethylase family increased H3K79me in human chondrocytes. Blockade of KDM2/7 histone demethylases with daminozide increased H3K79me and glycosaminoglycans. In mouse articular cartilage, H3K79me decayed rapidly upon induction of joint injury. Early and sustained intra-articular treatment with daminozide enhanced H3K79me and exerted protective effects in mice upon DMM. Individual silencing of KDM7A/B demethylases in human chondrocytes demonstrated that KDM7A/B mediate protective effects of daminozide on H3K79me and osteoarthritis.
Targeting KDM7A/B histone demethylases could be an attractive strategy to protect joints against osteoarthritis.
在骨关节炎中，组蛋白 H3 赖氨酸 79 上的甲基化（H3K79me）减少，这是一种保护性的表观遗传机制。组蛋白的甲基化水平受组蛋白甲基转移酶和去甲基酶的动态调节。在这里，我们的目的是确定哪些组蛋白去甲基酶调节软骨中的 H3K79me，并研究其靶向治疗是否能预防骨关节炎。
我们使用 qPCR 确定了人非骨关节炎和骨关节炎软骨中的组蛋白去甲基酶表达。通过用药理抑制剂处理人 C28/I2 软骨细胞，然后进行 Western blot 和免疫荧光，来研究组蛋白去甲基酶家族和亚家族对 H3K79me 的作用。我们进行 C28/I2 微团，通过 Alcian 蓝染色评估对糖胺聚糖的影响。通过免疫组织化学确定小鼠内侧半月板不稳定（DMM）后 H3K79me 的变化。在 DMM 后，将 KDM2/7 亚家族抑制剂氨甲喋呤关节内注射。在软骨细胞中单独沉默氨甲喋呤靶向的组蛋白去甲基酶，以剖析它们对 H3K79me 和骨关节炎的作用。
我们记录了人非骨关节炎和骨关节炎关节软骨中组蛋白去甲基酶的表达谱。抑制 Jumonji-C 去甲基酶家族增加了人软骨细胞中的 H3K79me。用氨甲喋呤阻断 KDM2/7 组蛋白去甲基酶增加了 H3K79me 和糖胺聚糖。在小鼠关节软骨中，关节损伤诱导后 H3K79me 迅速降解。早期和持续关节内用氨甲喋呤治疗增强了 H3K79me，并在 DMM 后对小鼠有保护作用。在人软骨细胞中单独沉默 KDM7A/B 去甲基酶表明，KDM7A/B 介导氨甲喋呤对 H3K79me 和骨关节炎的保护作用。
靶向 KDM7A/B 组蛋白去甲基酶可能是保护关节免受骨关节炎的一种有吸引力的策略。
