Wei Fulan, Wang Chunling, Zhou Gengyin, Liu Dongxu, Zhang Xiaofang, Zhao Yanhong, Zhang Yuhua, Yang Qifeng
Department of Orthodontics, Shandong University, Shandong Province, Jinan 250012, People's Republic of China.
Arch Oral Biol. 2008 Jan;53(1):35-43. doi: 10.1016/j.archoralbio.2007.07.008. Epub 2007 Sep 10.
The aim of this study was to examine the changes of ATF4 expression in cultured human periodontal ligament fibroblasts (hPDLF) after mechanical stimuli, and to investigate whether ATF4 is essential for the mechanical stress-induced hPDLF differentiation.
Reverse transcriptase polymerase chain reaction (RT-PCR) and western blotting were used to examine mRNA and protein levels of ATF4 expression in hPDLFs after application of centrifugal force. pMyc-ATF4 transfected cells were subjected to centrifugal force for 30min, and the changes of alkaline phosphatase (ALP) activity and osteocalcin (OCN), osteopontin (OPN), collagen I (COLI), bone sialoprotein (BSP) genes were measured to assess the differentiation of hPDLFs.
The mRNA and protein levels of ATF4 increased shortly and then decreased rapidly towards its pre-pressure levels. Overexpression of pMyc-ATF4 exhibited a greater increase in ALP activity and all four osteogenic genes compared to the untransfected cells in response to the centrifugal force.
Our results indicate that ATF4 is essential in response of hPDLFs to mechanical stress, resulting in increased differentiation of hPDLFs to osteoblast-like cells.
本研究旨在检测机械刺激后培养的人牙周膜成纤维细胞（hPDLF）中活化转录因子4（ATF4）表达的变化，并探讨ATF4对机械应力诱导的hPDLF分化是否至关重要。
应用逆转录聚合酶链反应（RT-PCR）和蛋白质印迹法检测离心力作用后hPDLF中ATF4表达的mRNA和蛋白质水平。将转染pMyc-ATF4的细胞进行30分钟的离心力处理，检测碱性磷酸酶（ALP）活性以及骨钙素（OCN）、骨桥蛋白（OPN）、I型胶原（COLI）、骨涎蛋白（BSP）基因的变化，以评估hPDLFs的分化情况。
ATF4的mRNA和蛋白质水平短暂升高，随后迅速降至压力前水平。与未转染细胞相比，转染pMyc-ATF4的细胞在离心力作用下，ALP活性及所有四个成骨基因的表达均有更大程度的增加。
我们的结果表明，ATF4对于hPDLF对机械应力的反应至关重要，可导致hPDLF向成骨样细胞的分化增加。
