Expression and nephron segment-specific distribution of major renal aquaporins (AQP1-4) in Equus caballus, the domestic horse.
Abstract: Aquaporins (AQPs) play fundamental roles in water and osmolyte homeostasis by facilitating water and small solute movement across plasma membranes of epithelial, endothelial, and other tissues. AQP proteins are abundantly expressed in the mammalian kidney, where they have been shown to play essential roles in fluid balance and urine concentration. Thus far, the majority of studies on renal AQPs have been carried out in laboratory rodents and sheep; no data have been published on the expression of AQPs in kidneys of equines or other large mammals. The aim of this comparative study was to determine the expression and nephron segment localization of AQP1-4 in Equus caballus by immunoblotting and immunohistochemistry with custom-designed rabbit polyclonal antisera. AQP1 was found in apical and basolateral membranes of the proximal convoluted tubules and thin descending limbs of the loop of Henle. AQP2 expression was specifically detected in apical membranes of cortical, medullary, and papillary collecting ducts. AQP3 was expressed in basolateral membranes of cortical, medullary, and papillary collecting ducts. Immunohistochemistry also confirmed AQP4 expression in basolateral membranes of cells lining the distal convoluted and connecting tubules. Western blots revealed high expression of AQP1-4 in the equine kidney. These observations confirm that AQPs are expressed in the equine kidney and are found in similar nephron locations to mouse, rat, and human kidney. Equine renal AQP proteins are likely to be involved in acute and chronic regulation of body fluid composition and may be implicated in water balance disorders brought about by colic and endotoxemia.
Publication Date: 2007-04-18 PubMed ID: 17442782DOI: 10.1152/ajpregu.00689.2005Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The study investigates the expression and specific location in the kidney nephron of the four major aquaporin proteins (AQP1-4) in the domestic horse (Equus caballus). Aquaporins play critical roles in body fluids homeostasis and regulation.
Background
- Aquaporins (AQPs) are proteins that facilitate the movement of water and small solutes across plasma membranes in various tissues, including the kidney.
- These proteins have been found to play significant roles in fluid balance and urine concentration in the mammalian kidney.
- Despite the critical role AQPs play in fluid homeostasis, no previous studies have been carried out on the expression of these proteins in equine or other large mammalian kidneys.
Aim and Methodology
- The aim of this research was to determine the expression and location within nephron segments of AQP1-4 in the domestic horse, Equus caballus.
- The researchers conducted this study through the use of immunoblotting and immunohistochemistry with custom-designed rabbit polyclonal antisera.
Findings
- AQP1 was discovered in both the apical and basolateral membranes of the proximal convoluted tubules and the thin descending limbs of the loop of Henle, a part of the kidney nephron.
- AQP2 was specifically found in the apical membranes of cortical, medullary and papillary collecting ducts.
- The researchers detected AQP3 in the basolateral membranes of the cortical, medullary and papillary collecting ducts.
- Immunohistochemistry confirmed the expression of AQP4 in the basolateral membranes of cells lining the distal convoluted and connecting tubules.
- Western blotting methods revealed a high expression of AQP1-4 in the equine kidney.
- These findings validated the presence of AQPs in equine kidneys and their locations are similar to those in the kidneys of mice, rats and humans.
Implications
- Equine renal AQP proteins are likely involved in the acute and chronic regulation of body fluid composition.
- They could possibly play a significant role in water balance disorders caused by conditions such as colic and endotoxemia in horses.
Cite This Article
APA
Floyd RV, Mason SL, Proudman CJ, German AJ, Marples D, Mobasheri A.
(2007).
Expression and nephron segment-specific distribution of major renal aquaporins (AQP1-4) in Equus caballus, the domestic horse.
Am J Physiol Regul Integr Comp Physiol, 293(1), R492-R503.
https://doi.org/10.1152/ajpregu.00689.2005 Publication
Researcher Affiliations
- Department of Physiology, Faculty of Veterinary Science, University of Liverpool, Liverpool, UK.
MeSH Terms
- Animals
- Antibody Specificity
- Aquaporins / metabolism
- Blotting, Western
- Electrophoresis, Polyacrylamide Gel
- Horses / metabolism
- Immunohistochemistry
- Kidney / metabolism
- Kidney Tubules / metabolism
- Kidney Tubules, Collecting / metabolism
- Nephrons / metabolism
- Oligonucleotide Array Sequence Analysis
- Peptides / metabolism
- Rats
Grant Funding
- VS/05/LIV/A5 / Wellcome Trust
Citations
This article has been cited 6 times.- Matchimakul P, Pongkan W, Kongtung P, Mektrirat R. Comparative quantitation of aquaporin-2 and arginine vasopressin receptor-2 localizations among chronic kidney disease and healthy kidney in dogs.. Vet World 2021 Oct;14(10):2773-2781.
- Kan Y, Zeng M, Zhang B, Li B, Wang S, Wang Y, Xu R, Wu Y, Zheng X, Feng W. Corallodiscus flabellata B.L. Burtt Extracts Stimulate Diuretic Activity and Regulate the Renal Expression of Aquaporins.. Evid Based Complement Alternat Med 2020;2020:6020817.
- Ewida SF, Al-Sharaky DR. Implication of Renal Aquaporin-3 in Fructose-Induced Metabolic Syndrome and Melatonin Protection.. J Clin Diagn Res 2016 Apr;10(4):CF06-11.
- Radin MJ, Yu MJ, Stoedkilde L, Miller RL, Hoffert JD, Frokiaer J, Pisitkun T, Knepper MA. Aquaporin-2 regulation in health and disease.. Vet Clin Pathol 2012 Dec;41(4):455-70.
- Cornock R, Langley-Evans SC, Mobasheri A, McMullen S. The impact of maternal protein restriction during rat pregnancy upon renal expression of angiotensin receptors and vasopressin-related aquaporins.. Reprod Biol Endocrinol 2010 Aug 31;8:105.
- Richardson SM, Knowles R, Marples D, Hoyland JA, Mobasheri A. Aquaporin expression in the human intervertebral disc.. J Mol Histol 2008 Jun;39(3):303-9.
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