Nakajima Akira, Ito Yoshihiro, Tanaka Eiji, Sano Remi, Karasawa Yoko, Maeno Masao, Iwata Koichi, Shimizu Noriyoshi, Shuler Charles F
Department of Orthodontics, Nihon University School of Dentistry, 1-8-13 Kanda Surugadai, Chiyoda-ku, Tokyo 1018310, Japan; Dental Research Center, Nihon University School of Dentistry, 1-8-13 Kanda Surugadai, Chiyoda-ku, Tokyo 1018310, Japan.
Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, BCC-239, La Jolla, CA 92037, USA.
Arch Oral Biol. 2014 Nov;59(11):1192-204. doi: 10.1016/j.archoralbio.2014.07.007. Epub 2014 Jul 24.
Reported expression patterns for TGF-β receptors (TβR-I, -II, and -III) during palatogenesis suggest that they play essential roles in the mechanisms leading to palatal fusion. The purpose of this study was to compare the functions of the three TβRs during palatal fusion.
Using organ culture of mouse palatal shelves, expression levels of TβR-I, -II, and -III were suppressed by transfecting the siRNAs siTβR-I, -II, and -III, respectively. Phosphorylation of SMAD2 was examined as an indicator of downstream signalling via each TβR. Linkage between TGF-β signalling and critical events in palatal fusion led to the use of, MMP-13 expression as an outcome measure for the function of the TGF-β receptors.
The siRNA treatment decreased the expression level of each receptor by more than 85%. When treated with either siTβR-I or -II, palatal shelves at E13+72 h were not fused, with complete clefting in the anterior and posterior regions. The middle palatal region following treatment with either siTβR-I or -II had fusion from one-half or one-third of the palatal region. Treatment with siTβR-III resulted in a persistent midline seam of medial edge epithelium (MEE) in the anterior region with islands of persistent MEE in the middle and posterior regions of the midline. Treatment with all three siTβRs altered the pattern of SMAD2 phosphorylation. Palatal shelf cultures treated with siTβR-I or -II, but not -III, showed altered MMP-13 expression levels.
The ability to identify and recover MEE and palatal mesenchymal cells during palatal fusion will aid in the evaluation of the different mechanistic events regulated by each TβR during palatogenesis.
有关转化生长因子-β受体（TβR-I、-II和-III）在腭形成过程中的表达模式报道表明，它们在导致腭融合的机制中发挥着重要作用。本研究的目的是比较三种TβR在腭融合过程中的功能。
利用小鼠腭突的器官培养，分别转染小干扰RNA（siRNA）siTβR-I、-II和-III来抑制TβR-I、-II和-III的表达水平。检测SMAD2的磷酸化作为通过每个TβR的下游信号传导指标。转化生长因子-β信号传导与腭融合中的关键事件之间的联系导致将基质金属蛋白酶-13（MMP-13）表达作为转化生长因子-β受体功能的结果指标。
siRNA处理使每个受体的表达水平降低了85%以上。用siTβR-I或-II处理时，E13+72小时的腭突未融合，前后区域完全裂开。用siTβR-I或-II处理后的腭中部区域有一半或三分之一的腭区域融合。用siTβR-III处理导致前部内侧边缘上皮（MEE）的中线缝持续存在，中线中部和后部区域有MEE岛持续存在。用所有三种siRNA处理均改变了SMAD2磷酸化模式。用siTβR-I或-II而非-III处理的腭突培养物显示MMP-13表达水平改变。
在腭融合过程中识别和回收MEE及腭间充质细胞的能力将有助于评估每个TβR在腭形成过程中调节的不同机制事件。
