Schacht Vivien, Dadras Soheil S, Johnson Louise A, Jackson David G, Hong Young-Kwon, Detmar Michael
Cutaneous Biology Research Center, Massachusetts General Hospital, Charlestown, Massachusetts, USA.
Am J Pathol. 2005 Mar;166(3):913-21. doi: 10.1016/S0002-9440(10)62311-5.
The mucin-type glycoprotein podoplanin is specifically expressed by lymphatic but not blood vascular endothelial cells in culture and in tumor-associated lymphangiogenesis, and podoplanin deficiency results in congenital lymphedema and impaired lymphatic vascular patterning. However, research into the biological importance of podoplanin has been hampered by the lack of a generally available antibody against the human protein, and its expression in normal tissues and in human malignancies has remained unclear. We generated a human podoplanin-Fc fusion protein and found that the commercially available mouse monoclonal antibody D2-40 specifically recognized human podoplanin, as assessed by enzyme-linked immunosorbent assay and Western blot analyses. We found that, in addition to lymphatic endothelium, podoplanin was also expressed by peritoneal mesothelial cells, osteocytes, glandular myoepithelial cells, ependymal cells, and by stromal reticular cells and follicular dendritic cells of lymphoid organs. These findings were confirmed in normal mouse tissues with anti-podoplanin antibody 8.1.1. Podoplanin was also strongly expressed by granulosa cells in normal ovarian follicles, and by ovarian dysgerminomas and granulosa cell tumors. Although podoplanin was primarily absent from normal human epidermis, its expression was strongly induced in 22 of 28 squamous cell carcinomas studied. These findings suggest a potential role of podoplanin in tumor progression, and they also identify the first commercially available antibody for the specific staining of a defined lymphatic marker in archival human tissue sections, thereby enabling more widespread studies of tumor lymphangiogenesis in human cancers.
黏蛋白型糖蛋白血小板内皮细胞黏附分子（Podoplanin）在培养的淋巴管内皮细胞而非血管内皮细胞中特异性表达，在肿瘤相关淋巴管生成中也是如此，并且血小板内皮细胞黏附分子缺乏会导致先天性淋巴水肿和淋巴管模式形成受损。然而，由于缺乏一种普遍可用的针对人类该蛋白的抗体，对血小板内皮细胞黏附分子生物学重要性的研究受到了阻碍，其在正常组织和人类恶性肿瘤中的表达仍不清楚。我们制备了一种人血小板内皮细胞黏附分子-Fc融合蛋白，通过酶联免疫吸附测定和蛋白质印迹分析评估发现，市售的小鼠单克隆抗体D2-40能特异性识别人类血小板内皮细胞黏附分子。我们发现，除了淋巴管内皮细胞外，血小板内皮细胞黏附分子还表达于腹膜间皮细胞、骨细胞、腺肌上皮细胞、室管膜细胞以及淋巴器官的基质网状细胞和滤泡树突状细胞。这些发现用抗血小板内皮细胞黏附分子抗体8.1.1在正常小鼠组织中得到了证实。血小板内皮细胞黏附分子在正常卵巢卵泡的颗粒细胞、卵巢无性细胞瘤和颗粒细胞瘤中也强烈表达。虽然正常人类表皮中基本不存在血小板内皮细胞黏附分子，但其在28例研究的鳞状细胞癌中有22例中表达强烈诱导。这些发现提示血小板内皮细胞黏附分子在肿瘤进展中可能发挥作用，并且它们还鉴定出了第一种可用于存档人类组织切片中特定淋巴管标志物特异性染色的市售抗体，从而能够更广泛地研究人类癌症中的肿瘤淋巴管生成。
