Immunohistochemical identification of aquaporin 2 in the kidneys of young beef cattle

Abstract

Aquaporin 2 (AQP2) is a small, integral tetrameric plasma membrane protein that is expressed in mammalian kidneys. The specific constitution of this protein and its selective permeability to water means that AQP2 plays an important role in hypertonic urine production. Immunolocalization of AQP2 has been studied in humans, monkeys, sheep, dogs, rabbits, rats, mice and adult cattle. We analyzed the expression of AQP2 in kidneys of 7-month-old Polish-Friesian var. black and white male calves. AQP2 was localized in the principal cells of collecting ducts in medullary rays penetrating the renal cortex and in the collecting ducts of renal medulla. AQP2 was expressed most strongly in the apical plasma membrane, but expression was observed also in the intracellular vesicles and basolateral plasma membrane. Our study provides new information concerning the immunolocalization of AQP2 in calf kidneys.

Aquaporin 2: Identification and analysis of expression in calves’ urine during their first month of life

“…The samples, warmed to 378C, were loaded on 12% polyacrylamide gels (5 mg denatured protein dissolved in SDS buffer per sample well) and run for 40 min at 200 V. After transfer by electroelution (25 V, 7 min) to PVDF membranes, the membranes were blocked with 5% non-fat milk in PBS-T (80 mM Na 2 HPO 4 , 20 mM NaH 2 PO 4 , 100 mM NaCl, and 0.1% Tween 20, pH 7.5) for 1 h and incubated overnight at 48C with rabbit polyclonal antibodies (H7661, Department of Biomedicine and Anatomy, Aarhus University, Denmark) diluted at a ratio of 1:1000. These antibodies have been successfully used in a variety of different applications in humans (Yanhong et al 2011), rats (Earm et al 1998), mice (Rojek et al 2006) and cattle (Michal ek et al 2013). This was followed by incubation with secondary anti-rabbit (P448, DAKO, Denmark) horseradish peroxidase-conjugated antibodies.…”

“…There is no information in the literature concerning urine AQP2 expression in farm animals, including calves. The sole data on the renal location of AQP2 in cattle is based on our previous research (Michal ek et al 2013) as well as a study conducted by Mobasheri et al (2011). Our recent study showed that in calves' kidneys the protein is located in the apical and basolateral plasma membrane and also in the intracellular vesicles of the collecting duct principal cells.…”

Immunohistochemical identification of aquaporin 2 in the kidneys of wild boars (Sus scrofa)

“…Nielsen et al (1993), in their study on location and analysis of AQP2 expression in the rat kidney, claimed that a small amount of this protein can also be found in the basolateral membrane of the collecting duct cells, especially in the inner medullary collecting duct principal cells. Weak, positive staining for AQP2 along the basolateral membrane of collecting duct cells was also reported by Fushimi et al (1993), Marples et al (1995), and Michałek et al (2014). According to these authors, the location of AQP2 in the basolateral membrane supports an exit pathway for the water across this membrane where abundant expression of AQP3 and AQP4 is also observed.…”

“…The studies conducted in humans and laboratory animals have been extended to other species. The presence of this protein in the kidney and its potential role in renal water retention has been confirmed in animals such as monkeys, dogs, rabbits, cattle, horses, and mini pigs (Loffing et al, 2000;Floyd et al, 2007;Bauchet et al, 2011;Mobasheri et al, 2011;Michałek et al, 2014;Lou et al, 2014). To date, however, this type of study has not been performed in free-living animals, including wild boars.…”

Effect of dietary supplementation with different levels of inulin-typefructans on renal expression of aquaporin 2 of growing piglets

“…intracellular vesicles and the basolateral membrane. The location, distribution, and expression of AQP2 observed in piglets examined was typical and characteristic of humans and other animal species (9,10).…”