Ekblom P, Klein G, Ekblom M, Sorokin L
Friedrich-Miescher-Laboratorium, Max-Planck-Gesellschaft, Tübingen, Germany.
Am J Kidney Dis. 1991 Jun;17(6):603-5. doi: 10.1016/s0272-6386(12)80329-5.
Epithelial cells have a polarized morphology, with distinct basal, lateral, and apical cell surfaces. It would be of considerable interest to know how the polarized morphology develops during embryogenesis. Both the tubular and glomerular epithelial cells of the kidney develop from mesenchymal stem cells during embryogenesis. A unique conversion of nonpolar cells to polarized epithelial cells thus occurs in the embryonic kidney. This conversion also occurs in vitro if the mesenchymal cells are properly induced. Organ cultures of mesenchymal cells from the mouse embryonic kidney have therefore been much used to study the development of epithelial cell polarity. We have used this model system to study the role of basement membrane glycoproteins in development. The results obtained suggest that laminins are particularly important for epithelial cell development. There are many different types of laminins. Developing kidney tubule cells synthesize a laminin isoform with the chain composition A-B1-B2, and it seems to promote development by interacting with specific integrin receptors on the cell surface. The mesenchymal stem cells also produce laminin B chains, but not the A chain, and they also lack the integrin receptor that interacts with A-B1-B2 laminin.
上皮细胞具有极化形态，具有明显的基底、侧面和顶端细胞表面。了解极化形态在胚胎发育过程中如何形成将非常有趣。肾脏的肾小管和肾小球上皮细胞在胚胎发育过程中均由间充质干细胞发育而来。因此，在胚胎肾脏中发生了非极性细胞向极化上皮细胞的独特转变。如果间充质细胞得到适当诱导，这种转变在体外也会发生。因此，来自小鼠胚胎肾脏的间充质细胞的器官培养物被大量用于研究上皮细胞极性的发育。我们利用这个模型系统研究基底膜糖蛋白在发育中的作用。获得的结果表明，层粘连蛋白对上皮细胞发育尤为重要。层粘连蛋白有许多不同类型。发育中的肾小管细胞合成一种链组成为A-B1-B2的层粘连蛋白异构体，它似乎通过与细胞表面的特定整合素受体相互作用来促进发育。间充质干细胞也产生层粘连蛋白B链，但不产生A链，并且它们也缺乏与A-B1-B2层粘连蛋白相互作用的整合素受体。
