The ER Ca2+ sensor STIM1 can activate osteoblast and odontoblast differentiation in mineralized tissues

ABSTRACT

Bone and dentin development requires temporal and spatial deposition of calcium phosphate mineral. A host of proteins works in concert to contribute to this tightly regulated process while malfunction in this scheme often leads to pathological defects. We have reported earlier that DMP1 stimulation of preosteoblasts leads to calcium release from internal Ca²⁺ stores and this store depletion is sensed by the ER Ca²⁺ sensor STIM1 (stromal interaction molecule 1). In this study, we first assessed the temporal and spatial localization of STIM1 protein during the development of bone and dentin by immunohistochemical methods. We further analyzed the function of STIM1 by establishing a stable MC3T3-E1 cell-line by overexpressing STIM1 (MC3T3-E1/STIM1 OE). Under mineralizing conditions, STIM1 overexpressing cells showed increased calcium deposits with higher expression of key osteogenic markers, such as Runx2 and type I collagen, BMP4 when compared with the control cells. Our results demonstrate that during mineralized matrix formation STIM1, the key ER sensor protein, can promote cellular differentiation in the presence of extracellular calcium.     

降钙素基因相关肽在大鼠切牙和牙周组织中的表达

目的:研究降钙素基因相关肽(calcitonin gene-related petide,CGRP)在大鼠切牙成釉细胞、成牙本质细胞和牙周膜细胞中的定位表达。方法:取6周龄Wistar大鼠的下颌骨,常规脱钙,切片,并进行HE染色和免疫组织化学染色,显微镜下观察CGRP在各组织细胞中的定位和表达。结果:CGRP在牙周膜细胞中呈阳性表达,在分泌期成釉细胞和成牙本质细胞中呈强阳性表达。结论:CGRP在牙齿硬组织发育细胞中呈强阳性表达,提示CGRP在釉质和牙本质发育的过程具有一定的意义。