As a member of the AFF (AF4/FMR2) family, AFF4 is a transcription elongation factor that is a component of the super elongation complex. AFF4 serves as a scaffolding protein that connects transcription factors and promotes gene transcription through elongation and chromatin remodelling. Here, we investigated the effect of AFF4 on human dental follicle cells (DFCs) in osteogenic differentiation. In this study, we found that small interfering RNA-mediated depletion of AFF4 resulted in decreased alkaline phosphatase (ALP) activity and impaired mineralization. In addition, the expression of osteogenic-related genes (DLX5, SP7, RUNX2 and BGLAP) was significantly downregulated. In contrast, lentivirus-mediated overexpression of AFF4 significantly enhanced the osteogenic potential of human DFCs. Mechanistically, we found that both the mRNA and protein levels of ALKBH1, a critical regulator of epigenetics, changed in accordance with AFF4 expression levels. Overexpression of ALKBH1 in AFF4-depleted DFCs partially rescued the impairment of osteogenic differentiation. Our data indicated that AFF4 promoted the osteogenic differentiation of DFCs by upregulating the transcription of ALKBH1.

作为AFF（AF4 / FMR2）家族的成员，AFF4是转录延伸因子，是超延伸复合体的组成部分。AFF4是一种连接转录因子并通过延伸和染色质重塑促进基因转录的支架蛋白。在这里，我们调查了成骨分化中AFF4对人牙囊细胞（DFCs）的影响。在这项研究中，我们发现小干扰RNA介导的AFF4耗竭导致碱性磷酸酶（ALP）活性降低和矿化受损。此外，成骨相关基因（DLX5，SP7，RUNX2和BGLAP）的表达）被大幅下调。相反，慢病毒介导的AFF4的过表达显着增强了人类DFC的成骨潜能。从机理上讲，我们发现表观遗传学的关键调节因子ALKBH1的mRNA和蛋白质水平均根据AFF4表达水平而变化。ALKBH1在AFF4耗尽的DFC中的过表达部分挽救了成骨分化的损伤。我们的数据表明，AFF4通过上调的转录促进牙囊的成骨分化ALKBH1。