The expression level of heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) during the odontogenic differentiation of hDPSCs was analyzed by RT-PCR and Western blot. The roles of hnRNP A1 in the alternative splicing of RUNX2 exon 5 and the odontogenic differentiation of dental mesenchymal cells were analyzed by gain- and loss-of-function experiments.
Surprisingly, we found an alternative splicing factor, hnRNP A1, which had an opposite role to YBX1 in regulating RUNX2 exon 5 inclusion and odontogenic differentiation of hDPSCs. Through gain- and loss-of-function assay, we found that hnRNP A1 suppressed the inclusion of RUNX2 exon 5, resulting in the inhibition of odontoblastic differentiation. The overexpression of hnRNP A1 can inhibit the expression of ALP (alkaline phosphatase) and OCN (osteocalcin), and the formation of mineralized nodules during the odontogenic differentiation of both hDPSCs and mouse dental papilla cells (mDPCs), whereas the opposite results were obtained with an hnRNP A1 knockdown preparation.
The present study indicated that hnRNP A1 suppressed RUNX2 exon 5 inclusion and reduced the odontogenic differentiation ability of hDPSCs and mDPCs.
通过RT-PCR和Westernblot分析了hDPSCs牙源性分化过程中异质核核糖核蛋白A1(hnRNPA1)的表达水平。通过功能增益和功能丧失实验分析了hnRNPA1在RUNX2外显子5的可变剪接和牙间充质细胞的牙源性分化中的作用。
令人惊讶的是,我们发现了一个可变的剪接因子,hnRNPA1在调节hDPSC的RUNX2外显子5包合和牙源性分化中具有与YBX1相反的作用。通过功能增益和丧失试验,我们发现hnRNPA1抑制了RUNX2外显子5的包含,从而抑制了成牙本质细胞的分化。hnRNPA1过表达可抑制碱性磷酸酶(ALP)和骨钙蛋白(OCN)的表达,以及在hDPSC和小鼠牙乳头细胞(mDPC)的牙源性分化过程中矿化结节的形成,而使用hnRNPA1敲除制剂获得了相反的结果。
本研究表明hnRNPA1抑制RUNX2外显子5包合,降低hDPSC和mDPC的牙源性分化能力。