Nephrogenic diabetes insipidus in mice lacking aquaporin-3 water channels
Nephrogenic diabetes insipidus in mice lacking aquaporin-3 water channels
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DOI：
10.1073/pnas.080499597
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发表时间：
2000-04-11
影响因子：
11.1
通讯作者：
Verkman, AS
中科院分区：
文献类型：
--
作者：
Ma, TH;Song, YL;Verkman, AS
水通道蛋白-3(Aquaporin-3，AQP3)是一种表达于肾集合管上皮细胞基底外侧质膜的水通道。克隆了小鼠AQP3基因，编码292个氨基酸的水/甘油转运糖蛋白，在肾脏、大气道、眼部、膀胱、皮肤和胃肠道表达。对小鼠的AQP3基因进行分析，通过靶向基因破坏的方法获得AQP3缺失小鼠。除多尿外，AQP3基因缺失小鼠的生长发育和表型基本正常。AQP3缺失对AQP1或AQP4蛋白表达影响不大，但降低AQP2蛋白表达，尤其是在肾皮质。AQP3基因缺失小鼠的液体消耗量是野生型小鼠的10倍以上，尿液渗透压(1,200 mliosol)，在给予1-去氨基-8-D-精氨酸加压素或缺水后，AQP3基因缺失小鼠能够部分浓缩尿液，接近野生型小鼠的30%。用空间滤波光学方法测量的皮质集合管基侧膜渗透水通透性因AQP3缺失而降低3倍。为了验证AQP3基因缺失小鼠的残留集中能力是由内髓集合管水通道引起的假说，我们建立了AQP4、AQP3/AQP4双基因敲除小鼠。与AQP3单基因敲除小鼠相比，双基因敲除小鼠对尿液浓缩能力的损害更大。我们的发现建立了一种形式的肾源性尿崩症，其原因是集合管基底膜的水通透性受损。因此，基底膜水孔蛋白可能为水通道抑制剂的药物发现提供血液可及的靶点。
Aquaporin-3 (AQP3) is a water channel expressed at the basolateral plasma membrane of kidney collecting-duct epithelial cells. The mouse AQP3 cDNA was isolated and encodes a 292-amino acid water/glycerol-transporting glycoprotein expressed in kidney, large airways, eye, urinary bladder, skin, and gastrointestinal tract. The mouse AQP3 gene was analyzed, and AQP3 null mice were generated by targeted gene disruption. The growth and phenotype of AQP3 null mice were grossly normal except for polyuria. AQP3 deletion had little eff ect on AQP1 or AQP4 protein expression but decreased AQP2 protein expression particularly in renal cortex. Fluid consumption in AQP3 null mice was more than 10-fold greater than that in wild-type litter mates, and urine osmolality (1,200 milliosmol), After 1-desamino-8-D-arginine-vasopressin administration or water deprivation, the AQP3 null mice were able to concentrate their urine partially to approximate to 30% of that in wild-type mice. Osmotic water permeability of cortical collecting-duct basolateral membrane, measured by a spatial filtering optics method, was > 3-fold reduced by AQP3 deletion. To test the hypothesis that the residual concentrating ability of AQP3 null mice was due to the inner medullary collecting-duct water channel AQP4 AQP3/AQP4 double-knockout mice were generated. The double-knockout mice had greater impairment of urinary-concentrating ability than did the AQP3 single-knockout mice. Our findings establish a form of nephrogenic diabetes insipidus produced by impaired water permeability in collecting-duct basolateral membrane. Basolateral membrane aquaporins may thus provide blood-accessible targets for drug discovery of aquaretic inhibitors.