Petridou S, Masur S K
Department of Ophthalmology, Mount Sinai School of Medicine, New York, NY 10029-6574, USA.
Invest Ophthalmol Vis Sci. 1996 Aug;37(9):1740-8.
In normal cornea, stromal fibroblasts (keratocytes) interact with one another by gap junctions. After corneal wounding, the remaining corneal stroma cells are phenotypically fibroblasts and myofibroblasts. For insight into the respective roles of fibroblasts and myofibroblasts in wound healing, the authors have investigated the molecular basis of cell-cell interaction in cultures of corneal fibroblasts and corneal myofibroblasts.
Using Western blot analysis and immunofluorescent microscopy, the authors determined the relative expression and localization of junction proteins-connexins, cadherins, and cadherin-associated proteins (catenins)-in cultured fibroblasts and myofibroblasts.
In cultured corneal fibroblasts, the gap junction protein, connexin 43, was highly expressed and was localized to dense maculae; cadherins were not detected in cell-cell contacts. Cultured myofibroblasts showed the opposite pattern: Cadherins were highly expressed and localized at the cell-cell contacts, whereas myofibroblast connexin 43 was primarily intracellular. Myofibroblast cadherin was identified by a pan-cadherin antibody as a molecule of 135 kDa that reacted weakly with an N-cadherin monoclonal antibody. In addition, cadherin-associated cytoplasmic proteins, alpha- and beta-catenins, co-localized with cadherin at the cell-cell borders of the myofibroblasts.
The presence of connexin 43 at the cell-cell borders of corneal fibroblasts is consistent with a primary communication role of junctions in confluent corneal fibroblasts. In contrast, the presence of cadherin at the cell-cel borders of myofibroblasts may provide a site for insertion of actin filaments. A cadherin-actin association could support actin-based force generation for effective wound closure.
在正常角膜中，基质成纤维细胞（角膜细胞）通过缝隙连接相互作用。角膜受伤后，剩余的角膜基质细胞在表型上为成纤维细胞和肌成纤维细胞。为深入了解成纤维细胞和肌成纤维细胞在伤口愈合中的各自作用，作者研究了角膜成纤维细胞和角膜肌成纤维细胞培养物中细胞间相互作用的分子基础。
作者使用蛋白质免疫印迹分析和免疫荧光显微镜，确定连接蛋白（连接蛋白、钙黏蛋白和钙黏蛋白相关蛋白（连环蛋白））在培养的成纤维细胞和肌成纤维细胞中的相对表达和定位。
在培养的角膜成纤维细胞中，缝隙连接蛋白连接蛋白43高度表达并定位于致密斑；在细胞间接触中未检测到钙黏蛋白。培养的肌成纤维细胞表现出相反的模式：钙黏蛋白高度表达并定位于细胞间接触处，而肌成纤维细胞连接蛋白43主要位于细胞内。肌成纤维细胞钙黏蛋白被一种泛钙黏蛋白抗体鉴定为135 kDa的分子，与N-钙黏蛋白单克隆抗体反应较弱。此外，钙黏蛋白相关的细胞质蛋白α-连环蛋白和β-连环蛋白与钙黏蛋白在肌成纤维细胞的细胞间边界共定位。
连接蛋白43在角膜成纤维细胞的细胞间边界处的存在与连接在汇合的角膜成纤维细胞中的主要通讯作用一致。相比之下，钙黏蛋白在肌成纤维细胞的细胞间边界处的存在可能为肌动蛋白丝的插入提供位点。钙黏蛋白-肌动蛋白关联可以支持基于肌动蛋白的力产生以实现有效的伤口闭合。
