Molecular Characterization of an Aquaporin−2 Mutation Causing Nephrogenic Diabetes Insipidus
The aquaporin 2 (AQP2) plays a critical role in water reabsorption to maintain water homeostasis. AQP2 mutation leads to nephrogenic diabetes insipidus (NDI), characterized by polyuria, polydipsia, and hypernatremia. We previously reported that a novel AQP2 mutation (G215S) caused NDI in a boy. In t...
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Format: | Article |
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Frontiers Media S.A.
2021-08-01
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Series: | Frontiers in Endocrinology |
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Online Access: | https://www.frontiersin.org/articles/10.3389/fendo.2021.665145/full |
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doaj-60be86ea8e6946e2ae09420f718463c7 |
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record_format |
Article |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Qian Li Bichao Lu Jia Yang Chao Li Yanchun Li Hui Chen Naishi Li Lian Duan Feng Gu Jianmin Zhang Weibo Xia |
spellingShingle |
Qian Li Bichao Lu Jia Yang Chao Li Yanchun Li Hui Chen Naishi Li Lian Duan Feng Gu Jianmin Zhang Weibo Xia Molecular Characterization of an Aquaporin−2 Mutation Causing Nephrogenic Diabetes Insipidus Frontiers in Endocrinology aquaporin 2 nephrogenic diabetes insipidus water reabsorption polydipsia hypernatremia |
author_facet |
Qian Li Bichao Lu Jia Yang Chao Li Yanchun Li Hui Chen Naishi Li Lian Duan Feng Gu Jianmin Zhang Weibo Xia |
author_sort |
Qian Li |
title |
Molecular Characterization of an Aquaporin−2 Mutation Causing Nephrogenic Diabetes Insipidus |
title_short |
Molecular Characterization of an Aquaporin−2 Mutation Causing Nephrogenic Diabetes Insipidus |
title_full |
Molecular Characterization of an Aquaporin−2 Mutation Causing Nephrogenic Diabetes Insipidus |
title_fullStr |
Molecular Characterization of an Aquaporin−2 Mutation Causing Nephrogenic Diabetes Insipidus |
title_full_unstemmed |
Molecular Characterization of an Aquaporin−2 Mutation Causing Nephrogenic Diabetes Insipidus |
title_sort |
molecular characterization of an aquaporin−2 mutation causing nephrogenic diabetes insipidus |
publisher |
Frontiers Media S.A. |
series |
Frontiers in Endocrinology |
issn |
1664-2392 |
publishDate |
2021-08-01 |
description |
The aquaporin 2 (AQP2) plays a critical role in water reabsorption to maintain water homeostasis. AQP2 mutation leads to nephrogenic diabetes insipidus (NDI), characterized by polyuria, polydipsia, and hypernatremia. We previously reported that a novel AQP2 mutation (G215S) caused NDI in a boy. In this study, we aimed to elucidate the cell biological consequences of this mutation on AQP2 function and clarify the molecular pathogenic mechanism for NDI in this patient. First, we analyzed AQP2 expression in Madin-Darby canine kidney (MDCK) cells by AQP2-G215S or AQP2-WT plasmid transfection and found significantly decreased AQP2-G215S expression in cytoplasmic membrane compared with AQP2-WT, independent of forskolin treatment. Further, we found co-localization of endoplasmic reticulum (ER) marker (Calnexin) with AQP2-G215S rather than AQP2-WT in MDCK cells by immunocytochemistry. The functional analysis showed that MDCK cells transfected with AQP2-G215S displayed reduced water permeability compared with AQP2-WT. Visualization of AQP2 structure implied that AQP2-G215S mutation might interrupt the folding of the sixth transmembrane α-helix and/or the packing of α-helices, resulting in the misfolding of monomer and further impaired formation of tetramer. Taken together, these findings suggested that AQP2-G215S was misfolded and retained in the ER and could not be translocated to the apical membrane to function as a water channel, which revealed the molecular pathogenic mechanism of AQP2-G215S mutation and explained for the phenotype of NDI in this patient. |
topic |
aquaporin 2 nephrogenic diabetes insipidus water reabsorption polydipsia hypernatremia |
url |
https://www.frontiersin.org/articles/10.3389/fendo.2021.665145/full |
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doaj-60be86ea8e6946e2ae09420f718463c72021-09-03T11:36:10ZengFrontiers Media S.A.Frontiers in Endocrinology1664-23922021-08-011210.3389/fendo.2021.665145665145Molecular Characterization of an Aquaporin−2 Mutation Causing Nephrogenic Diabetes InsipidusQian Li0Bichao Lu1Jia Yang2Chao Li3Yanchun Li4Hui Chen5Naishi Li6Lian Duan7Feng Gu8Jianmin Zhang9Weibo Xia10Department of Endocrinology, Key Laboratory of Endocrinology, NHC, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, ChinaDepartment of Immunology, Research Center on Pediatric Development and Diseases, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, State Key Laboratory of Medical Molecular Biology, Beijing, ChinaDepartment of Immunology, Research Center on Pediatric Development and Diseases, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, State Key Laboratory of Medical Molecular Biology, Beijing, ChinaDepartment of Immunology, Research Center on Pediatric Development and Diseases, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, State Key Laboratory of Medical Molecular Biology, Beijing, ChinaDepartment of Radiation Oncology, Stanford University, School of Medicine, Stanford, CA, United StatesDepartment of Immunology, Research Center on Pediatric Development and Diseases, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, State Key Laboratory of Medical Molecular Biology, Beijing, ChinaDepartment of Endocrinology, Key Laboratory of Endocrinology, NHC, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, ChinaDepartment of Endocrinology, Key Laboratory of Endocrinology, NHC, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, ChinaDepartment of Endocrinology, Key Laboratory of Endocrinology, NHC, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, ChinaDepartment of Immunology, Research Center on Pediatric Development and Diseases, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, State Key Laboratory of Medical Molecular Biology, Beijing, ChinaDepartment of Endocrinology, Key Laboratory of Endocrinology, NHC, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, ChinaThe aquaporin 2 (AQP2) plays a critical role in water reabsorption to maintain water homeostasis. AQP2 mutation leads to nephrogenic diabetes insipidus (NDI), characterized by polyuria, polydipsia, and hypernatremia. We previously reported that a novel AQP2 mutation (G215S) caused NDI in a boy. In this study, we aimed to elucidate the cell biological consequences of this mutation on AQP2 function and clarify the molecular pathogenic mechanism for NDI in this patient. First, we analyzed AQP2 expression in Madin-Darby canine kidney (MDCK) cells by AQP2-G215S or AQP2-WT plasmid transfection and found significantly decreased AQP2-G215S expression in cytoplasmic membrane compared with AQP2-WT, independent of forskolin treatment. Further, we found co-localization of endoplasmic reticulum (ER) marker (Calnexin) with AQP2-G215S rather than AQP2-WT in MDCK cells by immunocytochemistry. The functional analysis showed that MDCK cells transfected with AQP2-G215S displayed reduced water permeability compared with AQP2-WT. Visualization of AQP2 structure implied that AQP2-G215S mutation might interrupt the folding of the sixth transmembrane α-helix and/or the packing of α-helices, resulting in the misfolding of monomer and further impaired formation of tetramer. Taken together, these findings suggested that AQP2-G215S was misfolded and retained in the ER and could not be translocated to the apical membrane to function as a water channel, which revealed the molecular pathogenic mechanism of AQP2-G215S mutation and explained for the phenotype of NDI in this patient.https://www.frontiersin.org/articles/10.3389/fendo.2021.665145/fullaquaporin 2nephrogenic diabetes insipiduswater reabsorptionpolydipsiahypernatremia |