Smad4对小鼠眼睑发育的影响

Effect of Smad4 on development of eyelid

目的:利用眼特异性Smad4基因敲除小鼠,观察其眼睑表型并探讨其眼睑发育异常的可能机制。方法:选择PAX6第一启动子P0驱动的晶体外胚层特异性表达Cre重组酶的转基因小鼠(Le-Cre)作为介导敲除的工具鼠,将其与Smad4条件基因小鼠(Smad4fl/fl)交配获得Le-Cre特异性Smad4基因敲除小鼠,通过HE染色揭示其眼睑组织形态学的改变,采用免疫染色技术对某些关键蛋白的表达进行检测并与野生型小鼠进行比较,并检测其眼睑上皮细胞凋亡和增殖的改变。结果:Smad4在眼睑的失活导致眼睑在发育过程中不能融合,生后眼睑保持开放;Smad4在眼睑的表达缺失不影响眼睑睑缘上皮细胞的增殖和凋亡,但导致上皮细胞内c-Jun磷酸化过程受损,表皮生长因子受体(EGFR)核转位受影响,引起细胞内肌动蛋白束装配异常而导致上皮细胞移行受损,出现眼睑发育时融合不能。结论:Smad4在眼睑发育中对于眼睑的闭合是必需的。

AIM： To investigate the functional role of Smad4 in controlling the development of eyelid. METHODS： Using the Pax6 promoter-driven Cre transgenic mice,we conditionally inactivated Smad4 in the lens,cornea and ectoderm of the eyelids.HE staining was used to reveal the morphological changes in mutant mouse eyelids.Immunostaining for some key proteins was performed to detect the difference between wild-type and mutant mouse eyelids.The cell death and proliferation were compared between these 2 groups. RESULTS： Removal of Smad4 from the ectoderm of eyelid caused disruption to eyelids fusion and eyelids remained open at birth.Our data showed that inactivation of Smad4 in eyelid did not affect the cell differentiation and cell death of the eyelid epithelium,but led to impair the phosphorylation of c-Jun and nuclear translocation of epidermal growth factor receptor（EGFR） in the epithelial cells,which resulted in the disabled assembly of actin bundles in the epithelium.Therefore,epithelial migration was disrupted and eyelid closure failure occurred. CONCLUSION： Smad4 is required for the growth and fusion of eyelids.