Guo Feng, Feng Junsheng, Wang Feng, Li Wentong, Gao Qingping, Chen Zhuo, Shoff Lisa, Donly Kevin J, Gluhak-Heinrich Jelica, Chun Yong Hee Patricia, Harris Stephen E, MacDougall Mary, Chen Shuo
Department of Stomatology, Xiangya Hospital, Central South University, Changsha, China; Department of Developmental Dentistry, The University of Texas Health Science Center at San Antonio, Floyd Curl Drive, San Antonio, Texas.
J Cell Physiol. 2015 Aug;230(8):1871-82. doi: 10.1002/jcp.24915.
Although Bmp2 is essential for tooth formation, the role of Bmp2 during enamel formation remains unknown in vivo. In this study, the role of Bmp2 in regulation of enamel formation was investigated by the Bmp2 conditional knock out (Bmp2 cKO) mice. Teeth of Bmp2 cKO mice displayed severe and profound phenotypes with asymmetric and misshaped incisors as well as abrasion of incisors and molars. Scanning electron microscopy analysis showed that the enamel layer was hypoplastic and enamel lacked a typical prismatic pattern. Teeth from null mice were much more brittle as tested by shear and compressive moduli. Expression of enamel matrix protein genes, amelogenin, enamelin, and enamel-processing proteases, Mmp-20 and Klk4 was reduced in the Bmp2 cKO teeth as reflected in a reduced enamel formation. Exogenous Bmp2 up-regulated those gene expressions in mouse enamel organ epithelial cells. This result for the first time indicates Bmp2 signaling is essential for proper enamel development and mineralization in vivo.
尽管Bmp2对牙齿形成至关重要，但在体内，Bmp2在釉质形成过程中的作用仍不清楚。在本研究中，通过Bmp2条件性敲除（Bmp2 cKO）小鼠研究了Bmp2在调节釉质形成中的作用。Bmp2 cKO小鼠的牙齿表现出严重且显著的表型，包括不对称和畸形的门牙以及门牙和臼齿的磨损。扫描电子显微镜分析表明，釉质层发育不全，釉质缺乏典型的棱柱形图案。通过剪切和压缩模量测试，敲除小鼠的牙齿更脆。在Bmp2 cKO牙齿中，釉质基质蛋白基因、釉原蛋白、釉蛋白以及釉质加工蛋白酶Mmp - 20和Klk4的表达降低，这反映在釉质形成减少上。外源性Bmp2上调了小鼠釉质器官上皮细胞中的这些基因表达。这一结果首次表明Bmp2信号对于体内正常的釉质发育和矿化至关重要。
