基因组甲基转移酶G9a通过调节NFATc1功能来抑制骨质细胞生成和骨质再吸收
Koichiro Komatsu1, Hisashi Ideno1, Kazuhisa Nakashima1
1Department of Pharmacology, Tsurumi University School of Dental Medicine, Yokohama, Japan.
概括
表观遗传修饰剂G9a (EHMT2) 通常会抑制骨质细胞的形成. 在细胞和小鼠中删除G9a会增加骨质细胞活性和骨质损失,这表明G9a是治疗骨疾病的目标.
科学领域:
- 表观遗传学和转录的调节.
- 细胞分化和血统承诺
- 骨生物学和骨稳态.
背景情况:
- 表观遗传修饰,包括基因组甲基化,对于调节基因表达和细胞分化至关重要.
- G9a/EHMT2,一个关键的基因组甲基转移酶,催化H3K9甲基化,并影响各种细胞过程.
- 对于G9a在骨质细胞分化中的作用,这对于骨重塑至关重要的一个过程,仍然不完全理解.
研究的目的:
- 研究表观遗传修饰剂G9a在骨质细胞分化过程中的功能.
- 阐明G9a影响骨质细胞生成和骨代谢的分子机制.
主要方法:
- 在G9a缺乏的骨髓巨细胞 (BMM) 中,使用M-CSF和RANKL诱导了骨质细胞分化.
- 使用Cre重组腺病毒在体外和通过生成G9a条件淘汰 (cKO) 小鼠在体内实现了G9a删除.
- 分析了基因和蛋白质表达,基因组修饰水平 (H3K9me2),转录因子活性 (NFATc1) 和骨质再吸收试验.
主要成果:
- 删除G9a显著增加了骨质细胞的数量和活性,由TRAP阳性多核细胞和骨质再吸收的增加证明.
- 失去G9a导致骨质细胞标记物 (TRAP,cathepsin K) 的mRNA和蛋白质水平增加,并增强了NFATc1.1的核积累.
- 在雌性cKO小鼠中,G9a缺乏导致H3K9me2减少,NFATc1与Ctsk促进体结合增加,椎骨体积减少,血清CTX水平升高.
结论:
- G9a通过负面调节NFATc1活动和核定位,在骨质细胞形成中发挥着关键的抑制作用.
- 缺乏G9a会促进骨质细胞的分化和活动,导致骨质再吸收增加和骨质量减少.
- 向G9a可能为骨疾病提供治疗策略,其特点是骨质细胞过度活跃和骨质损失.
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