Mouse model of inducible nephrogenic diabetes insipidus produced by floxed aquaporin-2 gene deletion.
Mouse model of inducible nephrogenic diabetes insipidus produced by floxed aquaporin-2 gene deletion.
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DOI：
10.1152/ajprenal.00494.2005
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发表时间：
2006-08
期刊：
影响因子：
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通讯作者：
Baoxue Yang;Dan Zhao;Liman Qian;A. Verkman
中科院分区：
文献类型：
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作者：
Baoxue Yang;Dan Zhao;Liman Qian;A. Verkman
包括水通道蛋白-2(AQP2)在内的各种膜转运蛋白或受体蛋白缺失所产生的尿浓缩能力缺陷转基因小鼠模型与新生儿多尿症死亡率有关。在这里，我们报告了一种成年小鼠AQP2基因缺失并严重多尿的诱导性小鼠模型。通过在胚胎干细胞中同源重组，将loxP序列插入到小鼠AQP2基因内含子1和2中。胚系AQP2-loxP小鼠与他莫昔芬诱导表达Cre的小鼠交配，产生表型正常的Cre-AQP2-loxP可诱导纯合后代。注射他莫昔芬超过10天后，AQP2基因被切除，肾脏中检测不到全长AQP2转录本，免疫活性AQP2蛋白减少了95%。4-5天后，尿渗透压从大约2,000降至-lt；500 momoL/kgH(2)O，尿量从2毫升/天增加到25毫升/天。缺水后尿渗透压无明显增加。有趣的是，切除AQP2基因后，集合管中AQP3蛋白的表达增加了约5倍。多尿6周后出现轻度肾损害，集合管扩张，但内生肌酐清除率和血清生化指标正常。这些结果建立了第一个由AQP2缺乏引起的肾源性尿崩症(NDI)的成人模型，尽管与非诱导性NDI模型相比，每天的尿量与体重相当，但显著地保存了肾功能。
Transgenic mouse models of defective urinary concentrating ability produced by deletion of various membrane transport or receptor proteins, including aquaporin-2 (AQP2), are associated with neonatal mortality from polyuria. Here, we report an inducible mouse model of AQP2 gene deletion with severe polyuria in adult mice. LoxP sequences were inserted into introns 1 and 2 in the mouse AQP2 gene by homologous recombination in embryonic stem cells. Mating of germ-line AQP2-loxP mice with tamoxifen-inducible Cre-expressing mice produced offspring with inducible homozygous Cre-AQP2-loxP, which had a normal phenotype. Tamoxifen injections over 10 days resulted in AQP2 gene excision, with undetectable full-length AQP2 transcript in kidney and a >95% reduction in immunoreactive AQP2 protein. Urine osmolality decreased from approximately 2,000 to <500 mosmol/kgH(2)O after 4-5 days, with urine output increasing from 2 to 25 ml/day. Urine osmolality did not increase after water deprivation. Interestingly, AQP3 protein expression in the collecting duct was increased by about fivefold after AQP2 gene excision. Mild renal damage was seen after 6 wk of polyuria, with collecting duct dilatation, yet normal creatinine clearance and serum chemistries. These results establish the first adult model of nephrogenic diabetes insipidus (NDI) caused by AQP2 deficiency, with daily urine output comparable to body weight, although remarkable preservation of renal function compared with non-inducible NDI models.