Jahn L, Fouquet B, Rohe K, Franke W W
Division of Membrane Biology and Biochemistry, German Cancer Research Center, Heidelberg.
Differentiation. 1987;36(3):234-54. doi: 10.1111/j.1432-0436.1987.tb00198.x.
Using immunolocalization techniques, electron microscopy, and gel electrophoresis combined with immunoblotting, we have noted remarkable interspecies differences in the expression of cytokeratins in certain nonepithelial cells. In the present study we describe, in two taxonomically distant vertebrate species, the African clawed toad Xenopus laevis and man, endothelial and smooth muscle cells which express cytokeratin intermediate filaments (IFs), in addition to vimentin and/or desmin IFs. In Xenopus, all endothelia seem to produce both vimentin and cytokeratin IFs. As well, certain smooth muscle bundles located in the periphery of the walls of the esophagus and the urinary bladder produce small amounts of cytokeratin IFs in addition to IFs containing vimentin or desmin or both. The amphibian equivalents of human cytokeratins 8 and 18 have been identified in these nonepithelial tissues. In human endothelial cells, immunocytochemical reactions with certain cytokeratin antibodies are restricted to a rare subset of blood vessels. Vessels of this type were first noted in synovial and submucosal tissues, but also occur in some other locations. Cytokeratins have also been detected in certain groups of smooth muscles, such as those present in the walls of some blood vessels in synovial tissue and umbilical cord. Here, the synthesis of low levels of cytokeratins 8 and 18, sometimes with traces of cytokeratin 19, has been demonstrated in smooth muscle cells by colocalization with myogenic marker proteins, such as desmin and/or the smooth-muscle-specific isoform of alpha-actin. Possible reasons for the differences in cytokeratin expression between adjacent endothelia in man, and smooth-muscle structures in both species, as well as biologic and histodiagnostic implications of these findings, are discussed.
运用免疫定位技术、电子显微镜技术以及凝胶电泳结合免疫印迹法，我们注意到在某些非上皮细胞中细胞角蛋白的表达存在显著的种间差异。在本研究中，我们描述了在两种分类学上距离较远的脊椎动物物种——非洲爪蟾（非洲爪蟾）和人类中，内皮细胞和平滑肌细胞除了表达波形蛋白和/或结蛋白中间丝（IFs）外，还表达细胞角蛋白中间丝（IFs）。在非洲爪蟾中，所有内皮细胞似乎都能产生波形蛋白和细胞角蛋白IFs。同样，位于食管和膀胱壁外周的某些平滑肌束除了含有波形蛋白或结蛋白或两者的IFs外，还能产生少量的细胞角蛋白IFs。在这些非上皮组织中已经鉴定出了人类细胞角蛋白8和18的两栖类对应物。在人类内皮细胞中，与某些细胞角蛋白抗体的免疫细胞化学反应仅限于一小部分罕见的血管。这种类型的血管最初在滑膜和黏膜下组织中被发现，但也出现在其他一些部位。在某些平滑肌组中也检测到了细胞角蛋白，比如滑膜组织和脐带中一些血管壁中的平滑肌。在这里，通过与肌源性标记蛋白（如结蛋白和/或α -肌动蛋白的平滑肌特异性同工型）共定位，已经证实在平滑肌细胞中低水平地合成了细胞角蛋白8和18，有时还伴有细胞角蛋白19的痕迹。本文讨论了人类相邻内皮细胞之间以及这两个物种的平滑肌结构中细胞角蛋白表达差异的可能原因，以及这些发现的生物学和组织诊断意义。
