Iroquois homeobox 3 regulates odontoblast proliferation and differentiation mediated by Wnt5a expression
Iroquois homeobox 3 regulates odontoblast proliferation and differentiation mediated by Wnt5a expression
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DOI：
10.1016/j.bbrc.2023.02.004
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发表时间：
2023-02-09
影响因子：
3.1
通讯作者：
Iwamoto，Tsutomu
中科院分区：
文献类型：
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作者：
Narwidina，Anrizandy;Miyazaki，Aya;Iwamoto，Tsutomu
Iroquois同源异型盒基因是一类在物种间进化保守的TALE类同源异型盒基因，在基本组织发育过程中具有多种重要的细胞功能。以前的研究表明，Irxs基因在牙齿发育过程中表达。然而，基因在牙齿中的确切作用仍不清楚。在这里，我们首次证明了Irx 3是成牙本质细胞增殖和分化的重要分子。利用RT-PCR技术检测出生后第1天（P1）牙胚中Irx基因的表达，发现除Irx 4外，其他基因在牙胚中均有表达，其中Irx 1-Irx 3a在牙胚上皮细胞系M3 H1中表达，Irx 3和Irx 5在牙胚间充质细胞系mDP中表达。在两种未分化细胞系中只有Irx 3表达。免疫组化染色还显示，在牙齿上皮细胞和间充质凝聚中存在IRX 3。siRNA抑制内源性Irx 3可抑制mDP细胞的增殖和分化;定量PCR分析显示，Wnt 3a、Wnt 5a和Bmp 4在mDP细胞中高表达，是成牙本质细胞分化的重要调控因子。有趣的是，Irx 3siRNA抑制了Wnt 5a的表达（但不抑制Wnt 3和Bmp 4）。这些结果表明，Irx 3起着至关重要的作用，部分通过调节Wnt 5a的表达在成牙本质细胞的增殖和分化。
Iroquois homeobox (Irx) genes are TALE-class homeobox genes that are evolutionarily conserved across species and have multiple critical cellular functions in fundamental tissue development processes. Previous studies have shown that Irxs genes are expressed during tooth development. However, the precise roles of genes in teeth remain unclear. Here, we demonstrated for the first time that Irx3 is an essential molecule for the proliferation and differentiation of odontoblasts. Using cDNA synthesized from postnatal day 1 (P1) tooth germs, we examined the expression of all Irx genes (Irx1-Irx6) by RT-PCR and found that all genes exceptIrx4were expressed in the tooth tissue.Irx1-Irx3a were expressed in the dental epithelial cell line M3H1 cells, whileIrx3andIrx5were expressed in the dental mesenchymal cell line mDP cells. OnlyIrx3was expressed in both undifferentiated cell lines. Immunostaining also revealed the presence of IRX3 in the dental epithelial cells and mesenchymal condensation. Inhibition of endogenousIrx3by siRNA blocks the proliferation and differentiation of mDP cells.Wnt3a,Wnt5a, andBmp4are factors involved in odontoblast differentiation and were highly expressed in mDP cells by quantitative PCR analysis. Interestingly, the expression ofWnt5a(but notWnt3aorBmp4) was suppressed byIrx3siRNA. These results suggest that Irx3 plays an essential role in part through the regulation of Wnt5a expression during odontoblast proliferation and differentiation.