Hara-Chikuma Mariko, Verkman A S
Department of Medicine, Cardiovascular Research Institute, 1246 Health Sciences, East Tower, University of California, San Francisco, CA 94143-0521, USA.
J Am Soc Nephrol. 2006 Jan;17(1):39-45. doi: 10.1681/ASN.2005080846. Epub 2005 Nov 30.
Aquaporin-1 (AQP1) is the principal water-transporting protein in cell plasma membranes in kidney proximal tubule, where it facilitates transepithelial water transport. Here, a novel role for AQP1 in kidney involving the migration of proximal tubule cells is reported. Migration was compared in primary cultures of proximal tubule cells from wild-type and AQP1 null mice. Cell cultures from AQP1 null mice were indistinguishable from those of wild-type mice in their appearance, growth/proliferation, and adhesiveness, although, as expected, they had reduced plasma membrane water permeability. Migration of AQP1-deficient cells was reduced by >50% compared with wild-type cells, as measured in a Boyden chamber in the presence of a chemotactic stimulus. Comparable slowing of migration of AQP1-deficient cells was also found in an in vitro scratch assay of wound healing, with reduced appearance of lamella-like membrane protrusions at the cell leading edge. Adenoviral-mediated expression of AQP1 in the AQP1-deficient cells, which increased their water permeability to that of wild-type cells, corrected their migration defect. The potential relevance of these in vitro findings to the intact kidney was tested in an in vivo model of acute tubular injury caused by 30 min of renal artery occlusion. At 3 to 5 d after ischemia-reperfusion, kidneys in AQP1 null mice showed remarkably greater tubular injury and cellular actin disorganization than kidneys in wild-type mice. These results provide evidence for the involvement of AQP1 in migration of proximal tubule cells and possibly in the response of the proximal tubule to injury.
水通道蛋白-1（AQP1）是肾近端小管细胞质膜中主要的水转运蛋白，它促进跨上皮水转运。在此，报道了AQP1在肾脏中的一个新作用，即参与近端小管细胞的迁移。比较了野生型和AQP1基因敲除小鼠近端小管细胞原代培养物中的细胞迁移情况。尽管正如预期的那样，AQP1基因敲除小鼠的细胞培养物质膜水通透性降低，但其外观、生长/增殖和黏附性与野生型小鼠的细胞培养物并无差异。在存在趋化刺激的情况下，通过博伊登小室检测发现，与野生型细胞相比，AQP1缺陷细胞的迁移减少了50%以上。在体外伤口愈合划痕试验中也发现AQP1缺陷细胞的迁移同样减慢，细胞前缘的片状膜突起出现减少。腺病毒介导的AQP1在AQP1缺陷细胞中的表达增加了其水通透性，使其达到野生型细胞的水平，并纠正了其迁移缺陷。在肾动脉闭塞30分钟导致的急性肾小管损伤体内模型中，测试了这些体外研究结果与完整肾脏的潜在相关性。在缺血再灌注后3至5天，AQP1基因敲除小鼠的肾脏显示出比野生型小鼠的肾脏更严重的肾小管损伤和细胞肌动蛋白紊乱。这些结果为AQP1参与近端小管细胞迁移以及可能参与近端小管对损伤的反应提供了证据。
