Davideau J L, Papagerakis P, Hotton D, Lezot F, Berdal A
INSERM U-120, Hôpital Robert Debré, Paris, France.
Endocrinology. 1996 Aug;137(8):3577-85. doi: 10.1210/endo.137.8.8754789.
The aim of this study was to investigate the expression pattern of 1, 25-dihydroxyvitamin D3 receptor (VDR) and vitamin D-responsive gene expression during the steps of hard tissue formation in oro-facial development. In situ hybridization of VDR, alkaline phosphatase, and osteocalcin transcripts was performed in the mandibles of growing rats. Osteoblasts were used as the internal positive control for in situ detection of VDR messenger RNAs. Transcripts were present throughout the stages of differentiation and in differentiated osteoblasts and osteocytes, and showed some anatomical specificities in their developmental expression pattern. In dental tissues, VDR was strongly expressed in the inner dental epithelium at the beginning of the presecretion stage and, after a transient decrease at the end of the presecretion stage, in secretion stage ameloblasts. VDR was continuously expressed in epithelial supraameloblastic cells. During dentin formation, VDR was mainly present in subodontoblastic cells and was down-regulated during the terminal differentiation of odontoblasts. In these cells, VDR expression appeared to be induced by 1, 25-dihydroxyvitamin D3 injection. These data confirm that VDR is expressed in cells directly involved in mineralized tissue formation: ameloblasts, odontoblasts, and osteoblasts. Furthermore, they extend the idea of vitamin D sensitivity to cells that are not directly involved in this process: supraameloblastic, subodontoblastic, and osteoprogenitor cells. The differential expression pattern of VDR in odontoblasts and osteoblasts together with the similarity in the expression of potential vitamin D-responsive genes (osteocalcin in odontoblasts and osteoblasts, and alkaline phosphatase in osteoprogenitor and subodontoblastic cells) suggest the existence of a tissue specificity for the genomic action of 1, 25-dihydroxyvitamin D3, which may involve co-operation with additional nuclear factors.
本研究旨在探讨1,25 - 二羟基维生素D3受体（VDR）的表达模式以及在口腔面部发育过程中硬组织形成步骤期间维生素D反应性基因的表达情况。对生长中大鼠的下颌骨进行了VDR、碱性磷酸酶和骨钙素转录物的原位杂交。成骨细胞用作原位检测VDR信使核糖核酸的内部阳性对照。转录物存在于整个分化阶段以及分化的成骨细胞和骨细胞中，并且在其发育表达模式中表现出一些解剖学特异性。在牙组织中，VDR在分泌前期开始时在内釉上皮中强烈表达，在分泌前期结束时短暂下降后，在分泌期成釉细胞中表达。VDR在上釉上皮细胞中持续表达。在牙本质形成过程中，VDR主要存在于成牙本质细胞下层细胞中，并在成牙本质细胞终末分化期间下调。在这些细胞中，VDR表达似乎可通过注射1,25 - 二羟基维生素D3诱导。这些数据证实VDR在直接参与矿化组织形成的细胞中表达：成釉细胞、成牙本质细胞和成骨细胞。此外，它们将维生素D敏感性的概念扩展到未直接参与此过程的细胞：上釉上皮细胞、成牙本质细胞下层细胞和骨祖细胞。成牙本质细胞和成骨细胞中VDR的差异表达模式以及潜在的维生素D反应性基因（成牙本质细胞和成骨细胞中的骨钙素，以及骨祖细胞和成牙本质细胞下层细胞中的碱性磷酸酶）表达的相似性表明，1,25 - 二羟基维生素D3的基因组作用存在组织特异性，这可能涉及与其他核因子的合作。
