The role of GATA-binding protein 4 (GATA4) in neural crest cells (NCCs) is poorly defined. Here we showed that mouse NCCs lacking GATA4 exhibited developmental defects in craniofacial bone, teeth, and heart. The defects likely occurred due to decreased cell proliferation at the developmental stage. The in vitro results were consistent with the mouse model. The isobaric tags for relative and absolute quantitation assay revealed that BARX1 is one of the differentially expressed proteins after GATA4 knockdown in NCCs. On the basis of the results of dual-luciferase, electro-mobility shift, and chromatin immunoprecipitation assays, Barx1 expression is directly regulated by GATA4 in NCCs. In zebrafish, gata4 knockdown affects the development of NCCs derivatives. However, the phenotype in zebrafish could be partly rescued by co-injection of gata4 morpholino oligomers and barx1 mRNA. This study identified new downstream targets of GATA4 in NCCs and uncovered additional evidence of the complex regulatory functions of GATA4 in NCC development.

Rationale: Bone homeostasis is maintained by a balanced interplay of osteoblasts and osteoclasts. Osteoclasts are derived from monocyte/macrophage lineage. Major vault protein (MVP) is known to promote apoptosis and prevent metabolic diseases in macrophage. However, whether MVP is involved in osteoclastogenesis is unknown. Here, we identified an important function of MVP as a negative regulator of osteoclastogenesis and its therapeutic potential in preventing bone loss.

Growth disorders in the orofacial bone development process may lead to orofacial deformities. The balance between bone matrix formation by mesenchymal lineage osteoblasts and bone resorption by osteoclasts is vital for orofacial bone development. Although the mechanisms of orofacial mesenchymal stem cells (OMSCs) in orofacial bone development have been studied intensively, the communication between OMSCs and osteoclasts remains largely unclear.

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.