Knuppe Molecular Urology Laboratory, Department of Urology, School of Medicine, University of California, San Francisco, CA 94143-0738, USA.
Biochem Biophys Res Commun. 2011 Sep 23;413(2):353-7. doi: 10.1016/j.bbrc.2011.08.104. Epub 2011 Aug 27.
Stro-1 is the best-known mesenchymal stem cell (MSC) marker. However, previous studies have observed its expression in the endothelium. In the present study we performed immunofluorescence (IF) staining for Stro-1, using endothelial marker vWF as reference. In the liver, both proteins were expressed in the endothelium of the central veins and hepatic sinusoids. In the lung, both were expressed in the endothelium of pulmonary blood vessels, but while vWF was absent in the alveolar capillaries, Stro-1 was present. In the kidney, both were expressed in the endothelium of renal arterial branches, but while vWF was strongly expressed in the glomeruli, Stro-1 only scantly. IF staining in cultured endothelial cells also showed extensive overlaps between Stro-1 and vWF. Western blot analysis with Stro-1 antibody detected a single protein band of 75 kd in endothelial cells but not smooth muscle cells, fibroblasts, or B cells. Cancer cell lines PC3, DU145, MCF7, and K562 were also positive. Adipose-derived stem cells (ADSCs) expressed higher levels of Stro-1 when cultured beyond the first passage or when induced to differentiate into endothelial cells. These data, together with previous studies, indicate that Stro-1 is intrinsically an endothelial antigen, and its expression in MSC is probably an induced event.
Stro-1 是最著名的间充质干细胞（MSC）标志物。然而，之前的研究观察到它在内皮细胞中有表达。在本研究中，我们使用内皮标志物 vWF 作为参照，进行了 Stro-1 的免疫荧光（IF）染色。在肝脏中，这两种蛋白都在内皮细胞的中央静脉和肝窦中表达。在肺中，这两种蛋白都在肺血管的内皮细胞中表达，但 vWF 不存在于肺泡毛细血管中，而 Stro-1 存在。在肾脏中，这两种蛋白都在肾动脉分支的内皮细胞中表达，但 vWF 在肾小球中强烈表达，而 Stro-1 仅轻微表达。培养的内皮细胞中的 IF 染色也显示 Stro-1 和 vWF 之间存在广泛的重叠。Stro-1 抗体的 Western blot 分析在内皮细胞中检测到一条 75 kd 的单条蛋白带，但在平滑肌细胞、成纤维细胞或 B 细胞中没有检测到。前列腺癌细胞系 PC3、DU145、MCF7 和 K562 也呈阳性。脂肪来源的干细胞（ADSCs）在培养超过第一阶段或诱导分化为内皮细胞时，表达更高水平的 Stro-1。这些数据，连同之前的研究，表明 Stro-1 本质上是一种内皮抗原，其在 MSC 中的表达可能是一种诱导事件。
