Preliminary study on the role of peptidyl arginine deiminase 4 in the regulation of maxillofacial development

Objective To investigate the effect of peptidyl arginine deiminase 4(PAD4) on the differentiation of mesenchymal stem cells isolated from oral bones(OMSC) and craniomaxillofacial development. Methods Immunofluorescence was used to detect the expression of PAD4 in the mandibular of mice E13.5 embryo. A peptidyl arginine deiminase 4 knockout(PAD4-KO) mouse model was constructed. Craniomaxillofacial development was investigated by micro-CT. CCK-8 assay and Transwell assay were used to detect the OMSC proliferation ability and migration ability of PAD4-KO and wild type (WT) mouse. ALP staining was used to detect the changes in OMSC osteogenic differentiation ability. The expression of osteogenesis-related genes was detected by immunofluorescence and PCR assay. Results PAD4 was highly expressed in the mandibular tissue of mouse embryos at E13.5. On the cellular level, PAD4 was expressed in the nucleus and mitochondria of OMSC. Compared to the WT mice,micro-CT showed that PAD4-KO mice had retrusive jaw and decreased mineralization. The proliferation and migration ability of OMSC in PAD4-KO mice were decreased. OMSCs lacking PAD4 had significantly decreased ALP staining level, and the expression levels of osteogenesis-related genes were decreased. In addition, it was found that PAD4 might affect OMSC mineralization by regulating Runx2 transcription. Conclusion PAD4 is expressed in the jaw during embryonic development. It might affect the embryonic development by regulating the proliferation and differentiation of OMSC, leading to craniomaxillofacial abnormalities