Yoo Hong-Il, Lee Gye-Hyeok, Lee Su-Young, Kang Jee-Hae, Moon Jung-Sun, Kim Min-Seok, Kim Sun-Hun
Dental Science Research Institute, School of Dentistry, Chonnam National University, Gwangju, Korea.
J Anat. 2016 Jan;228(1):153-61. doi: 10.1111/joa.12387. Epub 2015 Oct 1.
Amelogenin, an enamel matrix protein has been considered to be exclusively expressed by ameloblasts during odontogenesis. However, burgeoning evidence indicates that amelogenin is also expressed in non-mineralizing tissues. Under the hypothesis that amelogenin may be a functional molecule in developing hair follicles which share developmental features with odontogenesis, this study for the first time elucidated the presence and functional changes of amelogenin and its receptors during rat hair follicle development. Amelogenin was specifically localized in the outer epithelial root sheath of hair follicles. Its expression appeared in the deeper portion of hair follicles, i.e. the bulbar and suprabulbar regions rather than the superficial region. Lamp-1, an amelogenin receptor, was localized in either follicular cells or outer epithelial sheath cells, reflecting functional changes during development. The expression of amelogenin splicing variants increased in a time-dependent manner during postnatal development of hair follicles. Amelogenin expression was increased by treatment with cyclosporin A, which is an inducer of anagen in the hair follicle, whereas the level of Lamp-1 and -2 was decreased by cyclosporin A treatment. These results suggest that amelogenin may be a functional molecule involved in the development of the hair follicle rather than an inert hair shaft matrix protein.
釉原蛋白是一种牙釉质基质蛋白，一直被认为在牙胚发生过程中仅由成釉细胞表达。然而，越来越多的证据表明，釉原蛋白也在非矿化组织中表达。基于釉原蛋白可能是在与牙胚发生具有共同发育特征的毛囊发育过程中的一种功能分子这一假设，本研究首次阐明了大鼠毛囊发育过程中釉原蛋白及其受体的存在和功能变化。釉原蛋白特异性定位于毛囊的外根鞘。其表达出现在毛囊较深的部分，即球部和球上部区域，而非浅表区域。釉原蛋白受体Lamp-1定位于毛囊细胞或外上皮鞘细胞中，反映了发育过程中的功能变化。在毛囊出生后发育过程中，釉原蛋白剪接变体的表达呈时间依赖性增加。用环孢素A处理可增加釉原蛋白的表达，环孢素A是毛囊生长期的诱导剂，而环孢素A处理可降低Lamp-1和Lamp-2的水平。这些结果表明，釉原蛋白可能是参与毛囊发育的功能分子，而不是一种惰性的毛干基质蛋白。
