Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China.
Sci Rep. 2017 May 8;7(1):1534. doi: 10.1038/s41598-017-01689-1.
Transcription factor GATA4 regulates cardiac and osteoblast differentiation. However, its role in tooth development is not clear. Therefore, we generated Wnt1-Cre;GATA4 mice, with conditional inactivation of the GATA4 gene in the dental papilla mesenchymal cells. Phenotypic analysis showed short root deformity along with reduced expressions of odonto/osteogenic markers. Proliferation (but not apoptosis) of cells around the apical area of the root was attenuated. In vitro, we knocked down GATA4 expression in stem cells of dental apical papilla (SCAPs). Proliferation, migration and odonto/osteogenic differentiation of SCAPs were affected in the shGATA4 group. Overexpression of GATA4 in SCAPs increased mineralization. Based on our previous iTRAQ results, guanine nucleotide binding proteins 3 (GNAI3) is one of the distinct proteins after GATA4 deletion. G protein signaling is involved in bone development, remodeling, and disease. In this study, both GATA4 deletion in the mouse root and knock-down in human SCAPs decreased the expression of GNAI3. Dual-luciferase and ChIP assay confirmed the direct binding of GATA4 to the GNAI3 promoter, both in vitro and in vivo. GNAI3 knock-down significantly decreased the odonto/osteogenic differentiation ability of SCAPs. We thus establish the role of GATA4 as a novel regulator of root development and elucidate its downstream molecular events.
转录因子 GATA4 调节心脏和成骨细胞分化。然而，其在牙齿发育中的作用尚不清楚。因此，我们生成了 Wnt1-Cre;GATA4 小鼠，在牙髓间质细胞中条件性敲除 GATA4 基因。表型分析显示根尖区变短，牙/成骨标志物表达减少。根尖区顶端周围细胞的增殖（而非凋亡）减弱。在体外，我们敲低了牙尖乳头干细胞（SCAPs）中的 GATA4 表达。shGATA4 组的增殖、迁移和成牙/成骨分化受到影响。GATA4 在 SCAPs 中的过表达增加了矿化。基于我们之前的 iTRAQ 结果，鸟嘌呤核苷酸结合蛋白 3（GNAI3）是 GATA4 缺失后明显的蛋白之一。G 蛋白信号转导参与骨骼发育、重塑和疾病。在这项研究中，小鼠根中 GATA4 的缺失和人 SCAPs 中的敲低均降低了 GNAI3 的表达。双荧光素酶和 ChIP 测定证实了 GATA4 体外和体内均直接结合到 GNAI3 启动子上。GNAI3 的敲低显著降低了 SCAPs 的牙/成骨分化能力。因此，我们确立了 GATA4 作为根发育新的调节因子的作用，并阐明了其下游分子事件。
