1
|
Kemter E, Rathkolb B, Bankir L, Schrewe A, Hans W, Landbrecht C, Klaften M, Ivandic B, Fuchs H, Gailus-Durner V, Hrabé de Angelis M, Wolf E, Wanke R, Aigner B. Mutation of the Na+-K+-2Cl−cotransporter NKCC2 in mice is associated with severe polyuria and a urea-selective concentrating defect without hyperreninemia. Am J Physiol Renal Physiol 2010; 298:F1405-15. [DOI: 10.1152/ajprenal.00522.2009] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The bumetanide-sensitive Na+-K+-2Cl−cotransporter NKCC2, located in the thick ascending limb of Henle's loop, plays a critical role in the kidney's ability to concentrate urine. In humans, loss-of-function mutations of the solute carrier family 12 member 1 gene ( SLC12A1), coding for NKCC2, cause type I Bartter syndrome, which is characterized by prenatal onset of a severe polyuria, salt-wasting tubulopathy, and hyperreninemia. In this study, we describe a novel chemically induced, recessive mutant mouse line termed Slc12a1I299Fexhibiting late-onset manifestation of type I Bartter syndrome. Homozygous mutant mice are viable and exhibit severe polyuria, metabolic alkalosis, marked increase in plasma urea but close to normal creatininemia, hypermagnesemia, hyperprostaglandinuria, hypotension,, and osteopenia. Fractional excretion of urea is markedly decreased. In addition, calcium and magnesium excretions are more than doubled compared with wild-type mice, while uric acid excretion is twofold lower. In contrast to hyperreninemia present in human disease, plasma renin concentration in homozygotes is not increased. The polyuria observed in homozygotes may be due to the combination of two additive factors, a decrease in activity of mutant NKCC2 and an increase in medullary blood flow, due to prostaglandin-induced vasodilation, that impairs countercurrent exchange of urea in the medulla. In conclusion, this novel viable mouse line with a missense Slc12a1 mutation exhibits most of the features of type I Bartter syndrome and may represent a new model for the study of this human disease.
Collapse
Affiliation(s)
- Elisabeth Kemter
- Chair for Molecular Animal Breeding and Biotechnology, and Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, and
- Institute of Veterinary Pathology, Center for Clinical Veterinary Medicine, LMU Munich, Munich
| | - Birgit Rathkolb
- Chair for Molecular Animal Breeding and Biotechnology, and Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, and
| | - Lise Bankir
- INSERM Unité 872, Centre de Recherche des Cordeliers, Paris, France
| | - Anja Schrewe
- Department of Medicine III, Division of Cardiology, University of Heidelberg, Heidelberg; and
- Institute of Experimental Genetics, Helmholtz Zentrum München, Neuherberg, and Chair for Experimental Genetics, Technische Universität München, Munich, Germany
| | - Wolfgang Hans
- Institute of Experimental Genetics, Helmholtz Zentrum München, Neuherberg, and Chair for Experimental Genetics, Technische Universität München, Munich, Germany
| | - Christina Landbrecht
- Chair for Molecular Animal Breeding and Biotechnology, and Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, and
| | - Matthias Klaften
- Institute of Experimental Genetics, Helmholtz Zentrum München, Neuherberg, and Chair for Experimental Genetics, Technische Universität München, Munich, Germany
| | - Boris Ivandic
- Department of Medicine III, Division of Cardiology, University of Heidelberg, Heidelberg; and
| | - Helmut Fuchs
- Institute of Experimental Genetics, Helmholtz Zentrum München, Neuherberg, and Chair for Experimental Genetics, Technische Universität München, Munich, Germany
| | - Valérie Gailus-Durner
- Institute of Experimental Genetics, Helmholtz Zentrum München, Neuherberg, and Chair for Experimental Genetics, Technische Universität München, Munich, Germany
| | - Martin Hrabé de Angelis
- Institute of Experimental Genetics, Helmholtz Zentrum München, Neuherberg, and Chair for Experimental Genetics, Technische Universität München, Munich, Germany
| | - Eckhard Wolf
- Chair for Molecular Animal Breeding and Biotechnology, and Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, and
| | - Ruediger Wanke
- Institute of Veterinary Pathology, Center for Clinical Veterinary Medicine, LMU Munich, Munich
| | - Bernhard Aigner
- Chair for Molecular Animal Breeding and Biotechnology, and Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, and
| |
Collapse
|
2
|
Herbach N, Rathkolb B, Kemter E, Pichl L, Klaften M, de Angelis MH, Halban PA, Wolf E, Aigner B, Wanke R. Dominant-negative effects of a novel mutated Ins2 allele causes early-onset diabetes and severe beta-cell loss in Munich Ins2C95S mutant mice. Diabetes 2007; 56:1268-76. [PMID: 17303807 DOI: 10.2337/db06-0658] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The novel diabetic mouse model Munich Ins2(C95S) was discovered within the Munich N-ethyl-N-nitrosourea mouse mutagenesis screen. These mice exhibit a T-->A transversion in the insulin 2 (Ins2) gene at nucleotide position 1903 in exon 3, which leads to the amino acid exchange C95S and loss of the A6-A11 intrachain disulfide bond. From 1 month of age onwards, blood glucose levels of heterozygous Munich Ins2(C95S) mutant mice were significantly increased compared with controls. The fasted and postprandial serum insulin levels of the heterozygous mutants were indistinguishable from those of wild-type littermates. However, serum insulin levels after glucose challenge, pancreatic insulin content, and homeostasis model assessment (HOMA) beta-cell indices of heterozygous mutants were significantly lower than those of wild-type littermates. The initial blood glucose decrease during an insulin tolerance test was lower and HOMA insulin resistance indices were significantly higher in mutant mice, indicating the development of insulin resistance in mutant mice. The total islet volume, the volume density of beta-cells in the islets, and the total beta-cell volume of heterozygous male mutants was significantly reduced compared with wild-type mice. Electron microscopy of the beta-cells of male mutants showed virtually no secretory insulin granules, the endoplasmic reticulum was severely enlarged, and mitochondria appeared swollen. Thus, Munich Ins2(C95S) mutant mice are considered a valuable model to study the mechanisms of beta-cell dysfunction and death during the development of diabetes.
Collapse
Affiliation(s)
- Nadja Herbach
- Institute of Veterinary Pathology, University of Munich, Munich, Germany.
| | | | | | | | | | | | | | | | | | | |
Collapse
|