Possible Roles of Msx2 in Ameloblast differentiation

Msx2 在成釉细胞分化中的可能作用

• 批准号: 13671897
• 负责人: KAWANO Yoshiro
• 金额: $ 1.66万
• 依托单位: NIIGATA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13671897/
• 关键词: Msx2; knockout mice; development; ameloblasts; stellate reticulum; stratum intermedium; immunohistochemistry; organ culture; ノックウアウトマウス; 上皮性幹細胞

Msx homeobox gene family which plays important roles in cell differentiation and proliferation is expressed in multipotent progenitor cells during organogenesis. Previous studies have shown that Msx2 mutant mice had defects in skull ossification and fusion of calvarial sutures. In this study, possible roles of Msx2 gene in odontogenesis were investigated by immunohistochemical and histological techniques, in comparison with phenotypes of one-day-old Msx2 mutant and wild type mice at each stage of amelogenesis. Furthermore, cultured incisor tooth germs of one-day-old mouse were processed for histologic analysis.No obvious phenotypic difference existed between the wild type and Msx2 mutant mice. The cervical loop also showed no discrepancy. However, abnormalities were found in the stratum intermedium and ameloblasts at the early stage of odontogenesis. The degree of abnormalities became more significant between the individual cells of ameloblasts and stratum intermedium in advance with cell differentiation. Each cell component expressed insufficient alkaline phosphatase activity. A part of ameloblasts secreted enamel protein. Similar abnormalities in vivo in the cultured stratum intermedium and ameloblasts were found. The differentiation of odontoblasts and dentin formation were intact. These findings suggest that Msx2 is essential for the development of the enamel organ.

Msx同源异型盒基因家族在器官形成过程中的多能祖细胞中表达，在细胞分化和增殖中起重要作用。先前的研究表明，Msx2突变小鼠在颅骨骨化和颅骨缝融合方面存在缺陷。在这项研究中，Msx2基因在牙齿发生的可能作用进行了研究，通过免疫组织化学和组织学技术，比较表型的1日龄Msx2突变和野生型小鼠在每个阶段的釉质形成。此外，对1日龄小鼠的切牙牙胚进行组织学分析，野生型和Msx2突变型小鼠之间没有明显的表型差异。颈环也没有显示出差异。但在牙胚发育早期，中间层和成釉细胞出现异常。随着细胞分化的提前，成釉细胞和中间层细胞之间的异常程度变得更加明显。每种细胞组分表达的碱性磷酸酶活性不足。部分成釉细胞分泌釉蛋白。在体内培养的中间层和成釉细胞也有类似的异常，成牙本质细胞的分化和牙本质的形成是完整的。这些发现表明Msx2对釉质器官的发育至关重要。