Servicio Autónomo Instituto de Biomedicina, Facultad de Medicina, Universidad Central de Venezuela, Caracas, Venezuela.
Eur J Histochem. 2011;55(2):e13. doi: 10.4081/ejh.2011.e13.
Endocan is a dermatan sulfate proteoglycan (DSPG) that has been observed in the cytoplasm of endothelial cells of small and large vessels in lung, kidney, liver, colon, ovary and brain tumors. This DSPG has been implicated in the regulation of cellular activities such as adhesion, migration, and proliferation. Given the important roles played by endocan in such processes, we sought to determine whether this DSPG is present in the chicken embryo aortic wall in embryonic days 12 and 14, when intimal thickening and endothelial transformation are notorious. Immunolabeling of serial paraffin cross-sections revealed endocan immunoreactivity at the endothelium and some mesenchymal cells constituting the intimal thickening but not in the cells arranged in lamellar layers. We also investigated whether endocan was present in monolayers of primary embryonic aortic endothelial cells attached to fibronectin when they were deprived of serum and stimulated with epidermal growth factor. Immunofluorescence determined that in the epidermal growth factor (EGF) condition where separating, detaching, and migrating cells were observed, endocan appeared organized in arrays typical of focal complexes in the leading edge of these cells. In serum-free medium condition in which the endothelial cells displayed a cobblestone appearance, endocan appeared mainly delineating the margin of many cells. This study demonstrates for the first time the presence of endocan during the aortic wall remodeling, and provides evidence that suggests a possible contribution of this DSPG in the endothelial-mesenchymal transition (EndoMT) process.
内皮下糖蛋白是一种硫酸乙酰肝素蛋白聚糖（DSPG），已在肺、肾、肝、结肠、卵巢和脑肿瘤中小血管和大血管的内皮细胞细胞质中观察到。这种 DSPG 参与调节细胞的黏附、迁移和增殖等活动。鉴于内皮下糖蛋白在这些过程中发挥着重要作用，我们试图确定这种 DSPG 是否存在于胚胎第 12 天和第 14 天的鸡胚主动脉壁中，此时内膜增厚和内皮转化是众所周知的。对石蜡切片的连续免疫标记显示，内皮下糖蛋白在构成内膜增厚的内皮细胞和一些间质细胞中具有免疫反应性，但不在排列成层状的细胞中。我们还研究了在血清剥夺和表皮生长因子（EGF）刺激下附着在纤维连接蛋白上的原代胚胎主动脉内皮细胞单层中是否存在内皮下糖蛋白。免疫荧光确定，在分离、脱离和迁移细胞的 EGF 条件下，内皮下糖蛋白出现在这些细胞前缘典型的局灶黏附复合物中。在无血清条件下，内皮细胞呈现鹅卵石样外观，内皮下糖蛋白主要描绘许多细胞的边缘。这项研究首次证明了内皮下糖蛋白在主动脉壁重塑过程中的存在，并提供了证据表明这种 DSPG 可能参与内皮-间充质转化（EndoMT）过程。
