Role of GATA binding protein 4 (GATA4) in the regulation of tooth development via GNAI3

Transcription factor GATA4 regulates cardiac and osteoblast differentiation. However, its role in tooth development is not clear. Therefore, we generated Wnt1-Cre;GATA4 fl/fl 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.