Human dental pulp cells (hDPCs) possess the capacity to differentiate into odontoblast-like cells in response to exogenous stimuli. Histone methylation is one of the most robust epigenetic marks and is essential for the regulation of multiple cellular processes. Previous studies have shown that histone methyltransferases (HMTs) and histone demethylases (HDMs) are crucial for the osteogenic differentiation of human bone marrow, adipose tissue, and tooth tissue. However, little is known about the role of histone methylation in hDPC differentiation. Here, the expression levels of HMTs and HDMs were profiled in hDPCs undergoing odontogenic induction. Among several differentially expressed enzymes, HDM KDM5A demonstrated significantly enhanced expression during cytodifferentiation. Furthermore, KDM5A expression increased during early passages and in a time-dependent manner during odontogenic induction. Using a shRNA-expressing lentivirus, KDM5A was knocked down in hDPCs. KDM5A depletion resulted in greater alkaline phosphatase activity and more mineral deposition formation. Meanwhile, the expression levels of the odontogenic markers DMP1, DSPP, OSX, and OCN were increased by KDM5A knockdown. As a histone demethylase specific for tri- and dimethylated histone H3 at lysine 4 (H3K4me3/me2), KDM5A deficiency led to a significant increment in total H3K4me3 levels, whereas no significant difference was found for H3K4 me2. H3K4me3 levels on the promoters of the odontogenic markers increased after KDM5A knockdown in hDPCs. These results demonstrated that KDM5A is present in hDPCs and inhibits the odontogenic differentiation potentiality of hDPCs by removing H3K4me3 from specific gene promoters, suggesting that KDM5A-dependent histone demethylation may play an important role in reparative dentinogenesis.

中文翻译：

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组蛋白脱甲基酶KDM5A对人牙髓细胞牙源性分化的影响。

人类牙髓细胞（hDPC）具有响应外源刺激分化为成牙本质细胞样细胞的能力。组蛋白甲基化是最可靠的表观遗传标记之一，对于调节多个细胞过程至关重要。先前的研究表明，组蛋白甲基转移酶（HMT）和组蛋白脱甲基酶（HDM）对于人类骨髓，脂肪组织和牙齿组织的成骨分化至关重要。但是，关于组蛋白甲基化在hDPC分化中的作用了解甚少。在这里，在经历牙源性诱导的hDPCs中分析了HMT和HDM的表达水平。在几种差异表达的酶中，HDM KDM5A在细胞分化过程中表现出明显增强的表达。此外，KDM5A表达在早期传代过程中增加，并在成牙诱导过程中呈时间依赖性。使用表达shRNA的慢病毒，在hDPC中敲除KDM5A。KDM5A耗尽导致更大的碱性磷酸酶活性和更多的矿物质沉积形成。同时，通过KDM5A抑制，增加了牙源性标记DMP1，DSPP，OSX和OCN的表达水平。作为赖氨酸4（H3K4me3 / me2）上三和二甲基化组蛋白H3特有的组蛋白脱甲基酶，KDM5A缺乏导致总H3K4me3水平显着增加，而H3K4 me2则无显着差异。在hDPC中敲除KDM5A后，牙源性标记启动子上的H3K4me3水平增加。