Aquaporin-11 knockout effect on kidney

Aquaporin-11 (AQP11), a new member of the aquaporin family, is localized in the endoplasmic reticulum (ER). Aqp11–/– mice neonatally suffer from polycystic kidneys derived from the proximal tubule. Its onset is proceeded by the vacuolization of ER. However, the mechanism for the formation of vacuoles and the development of cysts remain to be clarified. Here, we show that Aqp11–/– mice and polycystic kidney disease animals share a common pathogenic mechanism of cyst formation. Keywords: Geneexpression profile of Aqp11 knokout mouse kidney Aqp11+/– mice, originally generated in a 129/SvEvBrd background (4), were back-crossed 10–11 times to a C57/BL6 background. Heterozygous mice were interbred to obtain knockout (Aqp11–/–) and wild-type littermates (Aqp11+/+). The genotypes of offsprings were analyzed by PCR using tail DNA as a template. All animal experiments were approved by the Animal Care Committee of the University of Tokyo. One-week-old mice were sacrificed by cervical dislocation. Kidneys were rapidly excised on ice, washed in ice-cold phosphate-buffered saline, immersed in RNAlater (Ambion) and stored at –20°C. Total RNA was isolated using TRIzol Reagent (Invitrogen) and cleaned up using an RNeasy minikit with DNase treatment (Qiagen). The RNA quality and quantity were examined by agarose-gel electrophoresis and a spectrophotometer (GE Healthcare). Five pairs of Aqp11+/– mice were interbred, and we obtained 7 Aqp11+/+ and 9 Aqp11–/– offsprings. Three micrograms of total RNA obtained from each kidney was individually reverse-transcribed, amplified, and labeled using GeneChip One-Cycle Target Labeling and Control Reagent package (Affymetrix) according to the manufacturer’s protocol. Labeled cRNA was hybridized to GeneChip Mouse Genome 430 2.0 Array (Affymetrix) (a total of 16 samples on 16 different arrays). The arrays were washed, stained using Fluidics Station (Affymetrix), and then scanned with the GeneChip Scanner (Affymetrix). Data collection was performed using GeneChip Operating Software (Affymetrix). The quality of collected data was checked by scatter plot analysis.