Stepp M A, Zhu L, Cranfill R
Department of Anatomy and Cell Biology, George Washington University Medical Center, Washington, DC 20037, USA.
Invest Ophthalmol Vis Sci. 1996 Jul;37(8):1593-601.
To determine whether production and localization of beta 4 integrin is altered during in vivo corneal epithelial cell migration in response to debridement wounding.
Rat corneas were wounded and animals were killed at times ranging from 3 hours to 14 days. At various time points, corneal epithelial integrins were quantitated by gel electrophoresis and immunoblotting of epithelial extracts and then were localized by immunohistochemistry.
As early as 6 hours after wounding, an increase in the amount of the beta 4 integrin subunit expressed per microgram of total protein was observed. The level of beta 4 continued to increase until wound closure. By 14 days after wounding, beta 4 expression returned to control levels. The level of expression of beta 1 and alpha (v) integrins were found not to change significantly throughout migration. Immunohistochemical analyses using antibodies against either the beta 4 integrin subunit or HD1, a hemidesmosomal plaque component, showed that in control sections, beta 4 integrin and HD1 codistributed in a linear staining pattern above the basement membrane. As early as 4 hours after wounding, beta 4 was present in both basal and suprabasal epithelial cells, and HD1 was retained at the basal aspect of the epithelial basal cells.
These data show that changes in expression and localization of beta 4 integrin occur in the corneal epithelium in response to debridement wounding in vivo. Previously, we had shown that quantitative changes in beta 4 integrin expression do not occur in an in vitro organ culture model used for the study of corneal epithelial cell migration. Increased beta 4 expression may not be required for migration per se, but it may be play a role in either stabilizing cell:cell or cell:substrate adhesion in vivo or in preparing cells to undergo mitosis during restratification.
确定在因清创损伤而导致的体内角膜上皮细胞迁移过程中，β4整合素的产生和定位是否发生改变。
对大鼠角膜造成损伤，并在3小时至14天的不同时间点处死动物。在各个时间点，通过对上皮提取物进行凝胶电泳和免疫印迹来定量角膜上皮整合素，然后通过免疫组织化学进行定位。
早在受伤后6小时，就观察到每微克总蛋白中表达的β4整合素亚基数量增加。β4水平持续升高直至伤口闭合。受伤后14天，β4表达恢复到对照水平。发现在整个迁移过程中，β1和α(v)整合素的表达水平没有显著变化。使用针对β4整合素亚基或半桥粒斑块成分HD1的抗体进行的免疫组织化学分析表明，在对照切片中，β4整合素和HD1在基底膜上方呈线性染色模式共分布。早在受伤后4小时，β4就存在于基底和基底上层上皮细胞中，而HD1保留在上皮基底细胞的基底部分。
这些数据表明，在体内因清创损伤而导致的角膜上皮中，β4整合素的表达和定位发生了变化。此前，我们已经表明，在用于研究角膜上皮细胞迁移的体外器官培养模型中，β4整合素表达的定量变化并未发生。β4表达的增加本身可能不是迁移所必需的，但它可能在体内稳定细胞:细胞或细胞:基质黏附，或在复层化过程中使细胞准备进行有丝分裂方面发挥作用。
