Downregulation of the Cl-/HCO3-Exchanger Pendrin in Kidneys of Mice with Cystic Fibrosis: Role in the Pathogenesis of Metabolic Alkalosis
Background/Aims: Patients with cystic fibrosis (CF) are prone to the development of metabolic alkalosis; however, the pathogenesis of this life threatening derangement remains unknown. We hypothesized that altered acid base transport machinery in the kidney collecting duct underlies the mechanism of...
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Cell Physiol Biochem Press GmbH & Co KG
2018-02-01
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doaj-9697a59eae304e8ab578943f8b7740cd2020-11-24T21:44:26ZengCell Physiol Biochem Press GmbH & Co KGCellular Physiology and Biochemistry1015-89871421-97782018-02-014541551156510.1159/000487691487691Downregulation of the Cl-/HCO3-Exchanger Pendrin in Kidneys of Mice with Cystic Fibrosis: Role in the Pathogenesis of Metabolic AlkalosisMujan Varasteh KiaSharon BaroneAlicia A. McDonoughKamyar ZahediJie XuManoocher SoleimaniBackground/Aims: Patients with cystic fibrosis (CF) are prone to the development of metabolic alkalosis; however, the pathogenesis of this life threatening derangement remains unknown. We hypothesized that altered acid base transport machinery in the kidney collecting duct underlies the mechanism of impaired bicarbonate elimination in the CF kidney. Methods: Balance studies in metabolic cages were performed in WT and CFTR knockout (CF) mice with the intestinal rescue in response to bicarbonate loading or salt restriction, and the expression levels and cellular distribution of acid base and electrolyte transporters in the proximal tubule, collecting duct and small intestine were examined by western blots, northern blots and/or immunofluorescence labeling. Results: Baseline parameters, including acid-base and systemic vascular volume status were comparable in WT and CF mice, as determined by blood gas, kidney renin expression and urine chloride excretion. Compared with WT animals, CF mice demonstrated a significantly higher serum HCO3- concentration (22.63 in WT vs. 26.83 mEq/l in CF mice; n=4, p=0.013) and serum pH (7.33 in WT vs. 7.42 in CF mice; n=4, p=0.00792) and exhibited impaired kidney HCO3- excretion (urine pH 8.10 in WT vs. 7.35 in CF mice; n=7, p=0.00990) following a 3-day oral bicarbonate load. When subjected to salt restriction, CF mice developed a significantly higher serum HCO3- concentration vs. WT animals (29.26 mEq/L in CF mice vs. 26.72 in WT; n=5, p=0.0291). Immunofluorescence labeling demonstrated a profound reduction in the apical expression of the Cl-/HCO3- exchanger pendrin in cortical collecting duct cells and western and northern blots indicated diminished plasma membrane abundance and mRNA expression of pendrin in CF kidneys. Conclusions: We propose that patients with cystic fibrosis are prone to the development of metabolic alkalosis secondary to the inactivation of the bicarbonate secreting transporter pendrin, specifically during volume depletion, which is a common occurrence in CF patients.https://www.karger.com/Article/FullText/487691Metabolic AlkalosisCystic FibrosisPendrinCFTR |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Mujan Varasteh Kia Sharon Barone Alicia A. McDonough Kamyar Zahedi Jie Xu Manoocher Soleimani |
spellingShingle |
Mujan Varasteh Kia Sharon Barone Alicia A. McDonough Kamyar Zahedi Jie Xu Manoocher Soleimani Downregulation of the Cl-/HCO3-Exchanger Pendrin in Kidneys of Mice with Cystic Fibrosis: Role in the Pathogenesis of Metabolic Alkalosis Cellular Physiology and Biochemistry Metabolic Alkalosis Cystic Fibrosis Pendrin CFTR |
author_facet |
Mujan Varasteh Kia Sharon Barone Alicia A. McDonough Kamyar Zahedi Jie Xu Manoocher Soleimani |
author_sort |
Mujan Varasteh Kia |
title |
Downregulation of the Cl-/HCO3-Exchanger Pendrin in Kidneys of Mice with Cystic Fibrosis: Role in the Pathogenesis of Metabolic Alkalosis |
title_short |
Downregulation of the Cl-/HCO3-Exchanger Pendrin in Kidneys of Mice with Cystic Fibrosis: Role in the Pathogenesis of Metabolic Alkalosis |
title_full |
Downregulation of the Cl-/HCO3-Exchanger Pendrin in Kidneys of Mice with Cystic Fibrosis: Role in the Pathogenesis of Metabolic Alkalosis |
title_fullStr |
Downregulation of the Cl-/HCO3-Exchanger Pendrin in Kidneys of Mice with Cystic Fibrosis: Role in the Pathogenesis of Metabolic Alkalosis |
title_full_unstemmed |
Downregulation of the Cl-/HCO3-Exchanger Pendrin in Kidneys of Mice with Cystic Fibrosis: Role in the Pathogenesis of Metabolic Alkalosis |
title_sort |
downregulation of the cl-/hco3-exchanger pendrin in kidneys of mice with cystic fibrosis: role in the pathogenesis of metabolic alkalosis |
publisher |
Cell Physiol Biochem Press GmbH & Co KG |
series |
Cellular Physiology and Biochemistry |
issn |
1015-8987 1421-9778 |
publishDate |
2018-02-01 |
description |
Background/Aims: Patients with cystic fibrosis (CF) are prone to the development of metabolic alkalosis; however, the pathogenesis of this life threatening derangement remains unknown. We hypothesized that altered acid base transport machinery in the kidney collecting duct underlies the mechanism of impaired bicarbonate elimination in the CF kidney. Methods: Balance studies in metabolic cages were performed in WT and CFTR knockout (CF) mice with the intestinal rescue in response to bicarbonate loading or salt restriction, and the expression levels and cellular distribution of acid base and electrolyte transporters in the proximal tubule, collecting duct and small intestine were examined by western blots, northern blots and/or immunofluorescence labeling. Results: Baseline parameters, including acid-base and systemic vascular volume status were comparable in WT and CF mice, as determined by blood gas, kidney renin expression and urine chloride excretion. Compared with WT animals, CF mice demonstrated a significantly higher serum HCO3- concentration (22.63 in WT vs. 26.83 mEq/l in CF mice; n=4, p=0.013) and serum pH (7.33 in WT vs. 7.42 in CF mice; n=4, p=0.00792) and exhibited impaired kidney HCO3- excretion (urine pH 8.10 in WT vs. 7.35 in CF mice; n=7, p=0.00990) following a 3-day oral bicarbonate load. When subjected to salt restriction, CF mice developed a significantly higher serum HCO3- concentration vs. WT animals (29.26 mEq/L in CF mice vs. 26.72 in WT; n=5, p=0.0291). Immunofluorescence labeling demonstrated a profound reduction in the apical expression of the Cl-/HCO3- exchanger pendrin in cortical collecting duct cells and western and northern blots indicated diminished plasma membrane abundance and mRNA expression of pendrin in CF kidneys. Conclusions: We propose that patients with cystic fibrosis are prone to the development of metabolic alkalosis secondary to the inactivation of the bicarbonate secreting transporter pendrin, specifically during volume depletion, which is a common occurrence in CF patients. |
topic |
Metabolic Alkalosis Cystic Fibrosis Pendrin CFTR |
url |
https://www.karger.com/Article/FullText/487691 |
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