Barry-Lane P A, Wilson S E, Cavanagh H D, Petroll W M, Jester J V
Department of Ophthalmology, University of Texas Southwestern Medical Center at Dallas 75235-9057, USA.
Cornea. 1997 Jan;16(1):72-8.
The process of corneal wound healing involves the transformation of adjacent corneal keratocytes to myofibroblast-like cells characterized by the development of prominent microfilament bundles containing alpha-smooth muscle-specific actin (alpha-SM), a contractile protein thought to be important in mediating wound contraction. Recent studies have shown that the expression of alpha-SM in cultured corneal keratocytes can be induced by serum and TGF beta 1. To study the cellular and molecular mechanisms underlying this transformation process and to begin to identify the role of alpha-SM in wound contractile events, we generated immortalized rabbit corneal cell strains with extended life by using SV40 transfection. Two unique strains were isolated (TRK-36 and TRK-43). TRK-36, which appears similar to normal corneal keratocytes, maintains a stellate, keratocyte morphology when grown in the absence of serum and transforms to a myofibroblast-like cell when treated with TGF beta 1 (1 ng/ml), as indicated by the induced expression of alpha-SM actin. TRK-43 exhibits features characteristic of myofibroblasts in that it constitutively expresses alpha-SM actin under serum-free conditions. Both strains show in vitro contraction of collagen gels < or = 80% in 24 h in serum-containing medium. Interestingly, under serum-free conditions, TRK-43 cells showed significantly greater contraction of collagen gels compared with those of TRK-36. Overall, the establishment and further study of these cell strains may provide important insights into the molecular mechanisms underlying myofibroblast transformation.
角膜伤口愈合过程涉及相邻角膜基质细胞向肌成纤维细胞样细胞的转变，其特征是形成含有α-平滑肌特异性肌动蛋白（α-SM）的突出微丝束，α-SM是一种收缩蛋白，被认为在介导伤口收缩中起重要作用。最近的研究表明，血清和转化生长因子β1（TGFβ1）可诱导培养的角膜基质细胞中α-SM的表达。为了研究这种转变过程的细胞和分子机制，并开始确定α-SM在伤口收缩事件中的作用，我们通过使用SV40转染生成了具有延长寿命的永生化兔角膜细胞系。分离出两个独特的细胞系（TRK-36和TRK-43）。TRK-36看起来与正常角膜基质细胞相似，在无血清培养时保持星状的角膜基质细胞形态，在用TGFβ1（1 ng/ml）处理时转变为肌成纤维细胞样细胞，α-SM肌动蛋白的诱导表达表明了这一点。TRK-43表现出肌成纤维细胞的特征，即它在无血清条件下组成性表达α-SM肌动蛋白。在含血清培养基中，两种细胞系在24小时内均显示出胶原蛋白凝胶的体外收缩率≤80%。有趣的是，在无血清条件下，TRK-43细胞与TRK-36细胞相比，胶原蛋白凝胶的收缩明显更大。总体而言，这些细胞系的建立和进一步研究可能为肌成纤维细胞转变的分子机制提供重要见解。
