Tooth formation is a highly orchestrated process that precisely regulates the size and shape of the tooth.During typical tooth development,Hertwig’s epithelial root sheath(HERS)interacts with mesenchymal cells to dir...Tooth formation is a highly orchestrated process that precisely regulates the size and shape of the tooth.During typical tooth development,Hertwig’s epithelial root sheath(HERS)interacts with mesenchymal cells to direct the elongation of the tooth root and the deposition of dentin and cementum,thereby contributing to the formation of a fully developed tooth root.BMP9,a member of the BMP family,plays a significant role in growth,development,and cell differentiation.However,the precise function of BMP9 in dental root development remains unclear,particularly regarding its influence on HERS and odontoblasts.In this study,we utilized a mouse molar model to investigate the role of BMP9 signaling in tooth root development.The tooth formation of Bmp9 knockout(Bmp9-KO)mice and wild-type(WT)littermates was compared.Our findings revealed that Bmp9-KO mice exhibited shorter mandibular first molar roots,wider apical foramina,and thinner dentin compared with WT mice by micro-CT and hematoxylin-eosin staining analysis.Additionally,the results of immunohistochemistry and quantitative PCR indicated that in the absence of Bmp9,odontoblast differentiation and secretory function were compromised.Furthermore,Bmp9 ablation resulted in reduced cell proliferation and increased intercellular junctions within HERS,subsequently impacting root dentin formation and apical foramen closure.This study offers new insights into the regulatory role of BMP9 signaling in odontoblast and HERS function,highlighting its significance in root development and providing potential avenues for future research in tooth root regeneration.展开更多
Aim To characterize the odontogenic capability of apical bud and phenotypical change of apical bud cells （ABCs） in different microenvironment.Methodology Incisor apical bud tissues from neonatal SD rat were dissecte...Aim To characterize the odontogenic capability of apical bud and phenotypical change of apical bud cells （ABCs） in different microenvironment.Methodology Incisor apical bud tissues from neonatal SD rat were dissected and transplanted into the renal capsules to determine their odontogenic capability. Meanwhile ABCs were cultured and purified by repeated differential trypsinization. Then ABCs were cultured with conditioned medium from developing apical complex cells （DAC-CM）. Immunocytochemistry, reverse transcriptase polymerase chain reaction （RT-PCR） and scanning electron microscope （SEM） were performed to compare the biolo- gical change of ABC treated with or without DAC-CM. Results First we confirmed the ability of apical bud to form crown-like structure ectopically. Equally important, by using the developing apical complex （DAC） condi- tioned medium, we found the microenvironment created by root could abrogate the ＂crown＂ features of ABCs and promote their proliferation and differentiation. Conclusion ABCs possess odontogenic capability to form crown-like tissues and this property can be affected by root-produced microenvironment.展开更多
基金supported by the National Natural Science Foundation of China(No.82470977 to H.Z.,No.32070539 to W.L.)sponsored by the Natural Science Foundation of Chongqing,China(No.2024ZYYB005 to H.Z.).
文摘Tooth formation is a highly orchestrated process that precisely regulates the size and shape of the tooth.During typical tooth development,Hertwig’s epithelial root sheath(HERS)interacts with mesenchymal cells to direct the elongation of the tooth root and the deposition of dentin and cementum,thereby contributing to the formation of a fully developed tooth root.BMP9,a member of the BMP family,plays a significant role in growth,development,and cell differentiation.However,the precise function of BMP9 in dental root development remains unclear,particularly regarding its influence on HERS and odontoblasts.In this study,we utilized a mouse molar model to investigate the role of BMP9 signaling in tooth root development.The tooth formation of Bmp9 knockout(Bmp9-KO)mice and wild-type(WT)littermates was compared.Our findings revealed that Bmp9-KO mice exhibited shorter mandibular first molar roots,wider apical foramina,and thinner dentin compared with WT mice by micro-CT and hematoxylin-eosin staining analysis.Additionally,the results of immunohistochemistry and quantitative PCR indicated that in the absence of Bmp9,odontoblast differentiation and secretory function were compromised.Furthermore,Bmp9 ablation resulted in reduced cell proliferation and increased intercellular junctions within HERS,subsequently impacting root dentin formation and apical foramen closure.This study offers new insights into the regulatory role of BMP9 signaling in odontoblast and HERS function,highlighting its significance in root development and providing potential avenues for future research in tooth root regeneration.
基金supported by National Nature Science Foundation of China(Project No.3057 2046,30725042)
文摘Aim To characterize the odontogenic capability of apical bud and phenotypical change of apical bud cells （ABCs） in different microenvironment.Methodology Incisor apical bud tissues from neonatal SD rat were dissected and transplanted into the renal capsules to determine their odontogenic capability. Meanwhile ABCs were cultured and purified by repeated differential trypsinization. Then ABCs were cultured with conditioned medium from developing apical complex cells （DAC-CM）. Immunocytochemistry, reverse transcriptase polymerase chain reaction （RT-PCR） and scanning electron microscope （SEM） were performed to compare the biolo- gical change of ABC treated with or without DAC-CM. Results First we confirmed the ability of apical bud to form crown-like structure ectopically. Equally important, by using the developing apical complex （DAC） condi- tioned medium, we found the microenvironment created by root could abrogate the ＂crown＂ features of ABCs and promote their proliferation and differentiation. Conclusion ABCs possess odontogenic capability to form crown-like tissues and this property can be affected by root-produced microenvironment.
