Periodontal ligament cells (PDLCs) have well documented osteogenic potential; however, this commitment can be highly heterogenous, limiting their applications in tissue regeneration. In this study, we use PDLC populations characterized by high and low osteogenic potential (h-PDLCs and l-PDLCs, respectively) to identify possible sources of such heterogeneity and to investigate whether the osteogenic differentiation can be enhanced by epigenetic modulation. In h-PDLCs, low basal expression levels of pluripotency markers (NANOG, OCT4), DNA methyltransferases (DNMT1, DNMT3B), and enzymes involved in active DNA demethylation (TET1, TET3) were prerequisite to high osteogenic potential. Furthermore, these genes were downregulated upon early osteogenesis, possibly allowing for the increase in expression of the key osteogenic transcription factors, Runt-related transcription factor 2 (RUNX2) and SP7, and ultimately, mineral nodule formation. l-PDLCs appeared locked in the multipotent state and this was further enhanced upon early osteogenic stimulation, correlating with low RUNX2 expression and impaired mineralization. Further upregulation of DNMTs was also evident, while pretreatment with RG108, the DNMTs' inhibitor, enhanced the osteogenic program in l-PDLCs through downregulation of DNMTs, increased RUNX2 expression and nuclear localization, accelerated expression of osteogenic markers, and increased mineralization. These findings point toward the role of DNMTs and Ten Eleven Translocations (TETs) in osteogenic commitment and support application of epigenetic approaches to modulate biomineralization in PDLCs.

中文翻译：

---

DNMT1抑制剂可恢复牙周膜细胞中RUNX2的表达和矿化。

牙周膜细胞（PDLC）具有充分的成骨潜力；然而，这种承诺可能是高度异质的，从而限制了它们在组织再生中的应用。在这项研究中，我们使用具有高和低成骨潜能的PDLC群体（分别为h-PDLC和1-PDLC）来鉴定这种异质性的可能来源，并研究表观遗传调控是否可以增强成骨分化。在h-PDLC中，多能性标记（NANOG，OCT4），DNA甲基转移酶（DNMT1，DNMT3B）和参与活性DNA脱甲基化的酶（TET1，TET3）的基础表达水平较低）是高成骨潜能的前提。此外，这些基因在早期成骨过程中被下调，可能使关键成骨转录因子，Runt相关转录因子2（RUNX2）和SP7的表达增加，并最终导致矿物质结节的形成。I-PDLCs似乎锁定在多能状态，并且在早期成骨刺激后进一步增强，这与RUNX2表达低和矿化受损有关。DNMT的进一步上调也很明显，而DNMT抑制剂RG108的预处理通过下调DNMT增强了I-PDLC的成骨程序。s，增加RUNX2表达和核定位，加速成骨标记物的表达，并增加矿化作用。这些发现指向DNMT和十一个11易位（TET）在成骨作用中的作用，并支持表观遗传方法在PDLC中调节生物矿化的应用。