Korhonen M, Ylänne J, Laitinen L, Virtanen I
Department of Anatomy, University of Helsinki, Finland.
J Cell Biol. 1990 Sep;111(3):1245-54. doi: 10.1083/jcb.111.3.1245.
We studied the distribution of the alpha 1-alpha 6 subunits of beta 1 integrins in developing and adult human kidney using a panel of mAbs in indirect immunofluorescence microscopy. Uninduced mesenchyme displayed a diffuse immunoreactivity for only the alpha 1 integrin subunit. At the S-shaped body stage of nephron development, several of the alpha subunits were characteristically expressed in distinct fetal nephron segments, and the pattern was retained also in the adult nephron. Thus, the alpha 1 subunit was characteristically expressed in mesangial and endothelial cells, the alpha 2 in glomerular endothelium and distal tubules, the alpha 3 in podocytes, Bowman's capsule, and distal tubules, and the alpha 6 subunit basally in all tubules, and only transiently in podocytes during development. Unlike the alpha 3 and alpha 6 subunits, the alpha 2 subunit displayed an overall cell surface distribution in distal tubules. It was also distinctly expressed in glomerular endothelia during glomerulogenesis. The beta 4 subunit was expressed only in fetal collecting ducts, and hence the alpha 6 subunit seems to be complexed with the beta 1 rather than beta 4 subunit in human kidney. Of the two fibronectin receptor alpha subunits, alpha 4 and alpha 5, only the latter was expressed, confined to endothelia of developing and adult blood vessels, suggesting that these receptor complexes play a minor role during nephrogenesis. The present results suggest that distinct integrins play a role during differentiation of specific nephron segments. They also indicate that alpha 3 beta 1 and alpha 6 beta 1 integrin complexes may function as basement membrane receptors in podocytes and tubular epithelial cells.
我们使用一组单克隆抗体，通过间接免疫荧光显微镜研究了β1整合素的α1-α6亚基在发育中和成人肾脏中的分布。未诱导的间充质仅对α1整合素亚基呈现弥漫性免疫反应。在肾单位发育的S形期，几个α亚基在不同的胎儿肾单位节段有特征性表达，并且这种模式在成人肾单位中也得以保留。因此，α1亚基在系膜细胞和内皮细胞中有特征性表达，α2在肾小球内皮细胞和远曲小管中表达，α3在足细胞、鲍曼囊和远曲小管中表达，α6亚基在所有肾小管的基底表达，并且在发育过程中仅在足细胞中短暂表达。与α3和α6亚基不同，α2亚基在远曲小管中呈现整体细胞表面分布。它在肾小球发生过程中也在肾小球内皮细胞中明显表达。β4亚基仅在胎儿集合管中表达，因此在人肾中α6亚基似乎与β1而不是β4亚基形成复合物。在两种纤连蛋白受体α亚基α4和α5中，只有后者表达，局限于发育中和成人血管的内皮细胞，这表明这些受体复合物在肾发生过程中起次要作用。目前的结果表明，不同的整合素在特定肾单位节段的分化过程中起作用。它们还表明α3β1和α6β1整合素复合物可能在足细胞和肾小管上皮细胞中作为基底膜受体发挥作用。
