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Lan Q, Li J, Zhang H, Zhou Z, Fang Y, Yang B. Mechanistic complement of autosomal dominant polycystic kidney disease: the role of aquaporins. J Mol Med (Berl) 2024; 102:773-785. [PMID: 38668786 DOI: 10.1007/s00109-024-02446-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 04/05/2024] [Accepted: 04/09/2024] [Indexed: 05/21/2024]
Abstract
Autosomal dominant polycystic kidney disease is a genetic kidney disease caused by mutations in the genes PKD1 or PKD2. Its course is characterized by the formation of progressively enlarged cysts in the renal tubules bilaterally. The basic genetic explanation for autosomal dominant polycystic kidney disease is the double-hit theory, and many of its mechanistic issues can be explained by the cilia doctrine. However, the precise molecular mechanisms underpinning this condition's occurrence are still not completely understood. Experimental evidence suggests that aquaporins, a class of transmembrane channel proteins, including aquaporin-1, aquaporin-2, aquaporin-3, and aquaporin-11, are involved in the mechanism of autosomal dominant polycystic kidney disease. Aquaporins are either a potential new target for the treatment of autosomal dominant polycystic kidney disease, and further study into the physiopathological role of aquaporins in autosomal dominant polycystic kidney disease will assist to clarify the disease's pathophysiology and increase the pool of potential treatment options. We primarily cover pertinent findings on aquaporins in autosomal dominant polycystic kidney disease in this review.
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Affiliation(s)
- Qiumei Lan
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, 300193, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, 300193, China
| | - Jie Li
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, 300193, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, 300193, China
| | - Hanqing Zhang
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, 300193, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, 300193, China
| | - Zijun Zhou
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, 300193, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, 300193, China
| | - Yaxuan Fang
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, 300193, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, 300193, China
| | - Bo Yang
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, 300193, China.
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, 300193, China.
- Department of Nephrology, The First Affiliated Hospital of Tianjin University of Traditional Chinese Medicine, No.88, Changling Road, Xiqing District, Tianjin, 300193, China.
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Aggrey SE, Ghareeb AFA, Milfort MC, Ariyo OW, Aryal B, Hartono E, Kwakye J, Sovi S, Hipple SA, Stevenson C, Fuller AL, El Sabry MI, Stino F, Rekaya R. Quantitative and molecular aspects of water intake in meat-type chickens. Poult Sci 2023; 102:102973. [PMID: 37633082 PMCID: PMC10474491 DOI: 10.1016/j.psj.2023.102973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/21/2023] [Accepted: 07/24/2023] [Indexed: 08/28/2023] Open
Abstract
Even though water is the most essential nutrient for poultry production, adequate data on individual water intake in broiler chickens and its relationship with other traits of economic importance is scant. Water is provided to chickens in an unrestricted manner in spite of being a finite resource. Climate change continues to affect water sources and efficient bird use of water is long overdue. Understanding the biological basis of water intake is essential for sustainability of the poultry industry. Individual water and feed intake, and growth data was collected on 520 commercial broilers aged 14 to 42 days. We introduced the concepts of water conversion ratio (WCR) and residual water intake (RWI) as parameters that can be used to assess water intake efficiency. Water conversion ratio was defined as the amount of water consumed per unit of body weight gain, and RWI was defined as the difference between the actual water intake (WI) of a given bird and the expected WI by an average bird from the population with the same metabolic body weight, feed intake (FI) and body weight gain (BWG). The correlation between WI and FI was positive (r=0.77; P<0.0001), and the correlation between WI and BWG was positive (r=0.80; P<0.0001). Based on the distribution of RWI, the bottom 5 birds (LRWI) and the top 5 birds (HRWI) for RWI were selected for mRNA expression differences. The average broiler consumed about 7.8 L (± 1L) of water from 14 to 42 days of age. The mRNA expression of arginine vasopressin (AVP) antidiuretic hormone, calcium sensing receptor (CasR), sodium channel epithelial 1 subunit alpha (SCNN1A) and SCNN1D in the hypothalamus was upregulated in the LRWI group compared to the HRWI group. Similarly, kidney aquaporins (AQP) 2, 3, and 4 were upregulated in the LRWI group compared with the HRWI group. Given that water was provided ad libitum, the up-regulation of AVP and AQP gene mRNA expressions seem to indicate that the LRWI birds were more efficient in water reabsorption in the kidney compared to their HRWI counterparts. Increased water reabsorption will reduce the amount of water consumed to attain hydration. The water reabsorption potential was reflected in the excreta moisture levels as the LRWI birds had significantly lower excreta moisture than the HRWI birds. Excreta moisture level require further studies and could be considered as a potential proxy trait for water intake.
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Affiliation(s)
- Samuel E Aggrey
- Water Intake Genomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA, 30602.
| | - Ahmed F A Ghareeb
- Water Intake Genomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA, 30602
| | - Marie C Milfort
- Water Intake Genomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA, 30602
| | - Oluwatomide W Ariyo
- Water Intake Genomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA, 30602
| | - Bikash Aryal
- Water Intake Genomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA, 30602
| | - Evan Hartono
- Water Intake Genomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA, 30602
| | - Josephine Kwakye
- Water Intake Genomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA, 30602
| | - Selorm Sovi
- Water Intake Genomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA, 30602
| | - Sommer A Hipple
- Water Intake Genomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA, 30602
| | - Carrienton Stevenson
- Department of Agricultural Engineering Technology, Fort Valley State University, Fort Valley, GA, 31030
| | - Alberta L Fuller
- Water Intake Genomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA, 30602
| | | | - Farid Stino
- Department of Animal Production, Cairo University, Giza, Egypt
| | - Romdhane Rekaya
- Department of Animal and Dairy Science, University of Georgia, Athens, GA, 30602
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Qiu Z, Jiang T, Li Y, Wang W, Yang B. Aquaporins in Urinary System. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1398:155-177. [PMID: 36717493 DOI: 10.1007/978-981-19-7415-1_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
There are at least eight aquaporins (AQPs) expressed in the kidney. Including AQP1 expressed in proximal tubules, thin descending limb of Henle and vasa recta; AQP2, AQP3, AQP4, AQP5, and AQP6 expressed in collecting ducts; AQP7 expressed in proximal tubules; AQP8 expressed in proximal tubules and collecting ducts; and AQP11 expressed in the endoplasmic reticulum of proximal tubular epithelial cells. Over years, researchers have constructed different AQP knockout mice and explored the effect of AQP knockout on kidney function. Thus, the roles of AQPs in renal physiology are revealed, providing very useful information for addressing fundamental questions about transepithelial water transport and the mechanism of near isoosmolar fluid reabsorption. This chapter introduces the localization and function of AQPs in the kidney and their roles in different kidney diseases to reveal the prospects of AQPs in further basic and clinical studies.
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Affiliation(s)
- Zhiwei Qiu
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Tao Jiang
- College of Basic Medicine, Beihua University, Jilin, China
| | - Yingjie Li
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Weiling Wang
- Beijing Research Institute of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, P.R. China
| | - Baoxue Yang
- School of Basic Medical Sciences, Peking University, Beijing, China.
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Zhong QM, Wang JL. Seasonal flexibility of kidney structure and factors regulating water and salt in Eremias multiocellata. Comp Biochem Physiol A Mol Integr Physiol 2022; 274:111301. [DOI: 10.1016/j.cbpa.2022.111301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 08/21/2022] [Accepted: 08/21/2022] [Indexed: 12/05/2022]
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Leo KT, Chou CL, Yang CR, Park E, Raghuram V, Knepper MA. Bayesian analysis of dynamic phosphoproteomic data identifies protein kinases mediating GPCR responses. Cell Commun Signal 2022; 20:80. [PMID: 35659261 PMCID: PMC9164474 DOI: 10.1186/s12964-022-00892-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 04/28/2022] [Indexed: 11/18/2022] Open
Abstract
Background A major goal in the discovery of cellular signaling networks is to identify regulated phosphorylation sites (“phosphosites”) and map them to the responsible protein kinases. The V2 vasopressin receptor is a G-protein coupled receptor (GPCR) that is responsible for regulation of renal water excretion through control of aquaporin-2-mediated osmotic water transport in kidney collecting duct cells. Genome editing experiments have demonstrated that virtually all vasopressin-triggered phosphorylation changes are dependent on protein kinase A (PKA), but events downstream from PKA are still obscure. Methods Here, we used: 1) Tandem mass tag-based quantitative phosphoproteomics to experimentally track phosphorylation changes over time in native collecting ducts isolated from rat kidneys; 2) a clustering algorithm to classify time course data based on abundance changes and the amino acid sequences surrounding the phosphosites; and 3) Bayes’ Theorem to integrate the dynamic phosphorylation data with multiple prior “omic” data sets covering expression, subcellular location, known kinase activity, and characteristic surrounding sequences to identify a set of protein kinases that are regulated secondary to PKA activation. Results Phosphoproteomic studies revealed 185 phosphosites regulated by vasopressin over 15 min. The resulting groups from the cluster algorithm were integrated with Bayes’ Theorem to produce corresponding ranked lists of kinases likely responsible for each group. The top kinases establish three PKA-dependent protein kinase modules whose regulation mediate the physiological effects of vasopressin at a cellular level. The three modules are 1) a pathway involving several Rho/Rac/Cdc42-dependent protein kinases that control actin cytoskeleton dynamics; 2) mitogen-activated protein kinase and cyclin-dependent kinase pathways that control cell proliferation; and 3) calcium/calmodulin-dependent signaling. Conclusions Our findings identify a novel set of downstream small GTPase effectors and calcium/calmodulin-dependent kinases with potential roles in the regulation of water permeability through actin cytoskeleton rearrangement and aquaporin-2 trafficking. The proposed signaling network provides a stronger hypothesis for the kinases mediating V2 vasopressin receptor responses, encouraging future targeted examination via reductionist approaches. Furthermore, the Bayesian analysis described here provides a template for investigating signaling via other biological systems and GPCRs. Video abstract
Supplementary Information The online version contains supplementary material available at 10.1186/s12964-022-00892-6.
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Su W, Cao R, Zhang XY, Guan Y. Aquaporins in the kidney: physiology and pathophysiology. Am J Physiol Renal Physiol 2019; 318:F193-F203. [PMID: 31682170 DOI: 10.1152/ajprenal.00304.2019] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The kidney is the central organ involved in maintaining water and sodium balance. In human kidneys, nine aquaporins (AQPs), including AQP1-8 and AQP11, have been found and are differentially expressed along the renal tubules and collecting ducts with distinct and critical roles in the regulation of body water homeostasis and urine concentration. Dysfunction and dysregulation of these AQPs result in various water balance disorders. This review summarizes current understanding of physiological and pathophysiological roles of AQPs in the kidney, with a focus on recent progress on AQP2 regulation by the nuclear receptor transcriptional factors. This review also provides an overview of AQPs as clinical biomarkers and therapeutic targets for renal diseases.
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Affiliation(s)
- Wen Su
- Department of Pathophysiology, Shenzhen University Health Science Center, Shenzhen University, Shenzhen, China
| | - Rong Cao
- Department of Nephrology, The First Affiliated Hospital of Shenzhen University, Shenzhen, China.,The Second People's Hospital of Shenzhen, Shenzhen, China
| | - Xiao-Yan Zhang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, China
| | - Youfei Guan
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, China
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Vitamin D Regulates the Expressions of AQP-1 and AQP-4 in Mice Kidneys. BIOMED RESEARCH INTERNATIONAL 2019; 2019:3027036. [PMID: 30809535 PMCID: PMC6369492 DOI: 10.1155/2019/3027036] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 12/09/2018] [Accepted: 01/08/2019] [Indexed: 01/27/2023]
Abstract
Aim Vitamin D plays an important role in water and salt homeostasis. The aim of our study was to investigate the underlying relationship of Vitamin D and Aquaporins (AQP). Methods The behaviors of 1α (OH)-ase knockout mice and wild type mice were observed before analysis. The ICR mice were treated with vehicle or paricalcitol, a vitamin D analogue, followed by animals receiving a standard diet and free access to drinking water either with aliskiren (renin blocker; 37.5 mg aliskiren in 100 ml water), or telmisartan (a angiotensin II type I receptor blocker; 40 mg telmisartan in 100 ml water) a week before study. The expressions of AQP-1, AQP-4, and renin in mice kidneys were detected by western bolting, immunohistochemistry, and immunofluorescence. Results Diuresis and polydipsia were observed in 1α (OH)-ase knockout mice, and a decreased water intake and urine output in ICR mice was observed after paricalcitol treatment. Compared with wild type, the AQP-1 expressions were increased in renal papilla and AQP-4 expressions were decreased in renal proximal tubule of 1α(OH) ase knockout mice. In addition, AQP-1 was decreased in renal papilla and AQP-4 expressions were increased in proximal tubule by suppressing renin activity or supplement of Vitamin D analogue. After injecting renin into the lateral ventricle of the 1α(OH)ase knockout mice, the renin expression level was decreased in the kidney, followed by the decrease of AQP-1 in renal papilla and increase of AQP-4 in proximal tubule. Conclusions Overall, Vitamin D and renin inhibitors have synergistic effects in regulating water channels in mice kidneys.
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Sisto M, Ribatti D, Lisi S. Aquaporin water channels: New perspectives on the potential role in inflammation. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2019; 116:311-345. [PMID: 31036295 DOI: 10.1016/bs.apcsb.2018.11.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Aquaporins (AQPs) are a family of membrane water channel proteins that osmotically modulate water fluid homeostasis in several tissues; some of them also transport small solutes such as glycerol. At the cellular level, the AQPs regulate not only cell migration and transepithelial fluid transport across membranes, but also common events that are crucial for the inflammatory response. Emerging data reveal a new function of AQPs in the inflammatory process, as demonstrated by their dysregulation in a wide range of inflammatory diseases including edematous states, cancer, obesity, wound healing and several autoimmune diseases. This chapter summarizes the discoveries made so far about the structure and functions of the AQPs and provides updated information on the underlying mechanisms of AQPs in several human inflammatory diseases. The discovery of new functions for AQPs opens new vistas offering promise for the discovery of mechanisms and therapeutic opportunities in inflammatory disorders.
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Affiliation(s)
- Margherita Sisto
- Department of Basic Medical Sciences, Neurosciences and Sensory Organs (SMBNOS), Section of Human Anatomy and Histology, University of Bari "Aldo Moro", Bari, Italy.
| | - Domenico Ribatti
- Department of Basic Medical Sciences, Neurosciences and Sensory Organs (SMBNOS), Section of Human Anatomy and Histology, University of Bari "Aldo Moro", Bari, Italy
| | - Sabrina Lisi
- Department of Basic Medical Sciences, Neurosciences and Sensory Organs (SMBNOS), Section of Human Anatomy and Histology, University of Bari "Aldo Moro", Bari, Italy
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Nawata CM, Pannabecker TL. Mammalian urine concentration: a review of renal medullary architecture and membrane transporters. J Comp Physiol B 2018; 188:899-918. [PMID: 29797052 PMCID: PMC6186196 DOI: 10.1007/s00360-018-1164-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 04/23/2018] [Accepted: 05/14/2018] [Indexed: 01/10/2023]
Abstract
Mammalian kidneys play an essential role in balancing internal water and salt concentrations. When water needs to be conserved, the renal medulla produces concentrated urine. Central to this process of urine concentration is an osmotic gradient that increases from the corticomedullary boundary to the inner medullary tip. How this gradient is generated and maintained has been the subject of study since the 1940s. While it is generally accepted that the outer medulla contributes to the gradient by means of an active process involving countercurrent multiplication, the source of the gradient in the inner medulla is unclear. The last two decades have witnessed advances in our understanding of the urine-concentrating mechanism. Details of medullary architecture and permeability properties of the tubules and vessels suggest that the functional and anatomic relationships of these structures may contribute to the osmotic gradient necessary to concentrate urine. Additionally, we are learning more about the membrane transporters involved and their regulatory mechanisms. The role of medullary architecture and membrane transporters in the mammalian urine-concentrating mechanism are the focus of this review.
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Affiliation(s)
- C Michele Nawata
- Department of Physiology, Banner University Medical Center, University of Arizona, 1501 N. Campbell Avenue, Tucson, AZ, 85724-5051, USA.
| | - Thomas L Pannabecker
- Department of Physiology, Banner University Medical Center, University of Arizona, 1501 N. Campbell Avenue, Tucson, AZ, 85724-5051, USA
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Deneysel epilepsi modelinde böbrekte bulunan aquaporin4 ve aquaporin2 kanallarının gen ekspresyonları. JOURNAL OF CONTEMPORARY MEDICINE 2018. [DOI: 10.16899/gopctd.441193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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11
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AQP4 and HIVAN. Exp Mol Pathol 2018; 105:71-75. [PMID: 29778884 DOI: 10.1016/j.yexmp.2018.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 05/13/2018] [Indexed: 11/21/2022]
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Elgot A, El Hiba O, Belkouch M, Gamrani H. The underlying physiological basis of the desert rodent Meriones shawi's survival to prolonged water deprivation: Central vasopressin regulation on peripheral kidney water channels AQPs-2. Acta Histochem 2018; 120:65-72. [PMID: 29217107 DOI: 10.1016/j.acthis.2017.11.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 11/15/2017] [Accepted: 11/17/2017] [Indexed: 12/19/2022]
Abstract
Meriones shawi (M. shawi) is a particular semi-desert rodent known by its resistance to long periods of thirst. The aim of the present investigation is to clarify the underlying mechanisms allowing M. shawi to resist to hard conditions of dehydration. For this reason we used two different approaches: i) a morphometric study, which consists in measuring the effect of dehydration on body and kidneys weights as well as the report kidney weight/body weight, ii) By immunohistochemistry, we proceed to study the effect of dehydration on the immunoreactivity of central vasopressin (AVP) and the kidney aquaporin-2 (AQP-2) which is a channel protein that allows water to permeate across cell membranes. Our results showed both a body mass decrease accompanied by a remarkable kidneys hypertrophy. The immunohistochemical study showed a significant increase of AQP-2 immunoreactivity in the medullar part of Meriones kidneys allowing probably to Meriones a great ability to water retention. Consistently, we demonstrate that the increased AQP-2 expression occurred together with an increase in vasopressin (AVP) expression in both hypothalamic supraoptic (SON) and paraventricular nucleus (PVN), which are a major hub in the osmotic control circuitry. These various changes seen either in body weight and kidneys or at the cellular level might be the basis of peripheral control of body water homeostasis, providing to M. shawia strong resistance against chronic dehydration.
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Rahman SS, Moffitt AEJ, Trease AJ, Foster KW, Storck MD, Band H, Boesen EI. EHD4 is a novel regulator of urinary water homeostasis. FASEB J 2017; 31:5217-5233. [PMID: 28778975 DOI: 10.1096/fj.201601182rr] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 07/25/2017] [Indexed: 01/08/2023]
Abstract
The Eps15-homology domain-containing (EHD) protein family comprises 4 members that regulate endocytic recycling. Although the kidney expresses all 4 EHD proteins, their physiologic roles are largely unknown. This study focused on EHD4, which we found to be expressed differentially across nephron segments with the highest expression in the inner medullary collecting duct. Under baseline conditions, Ehd4-/- [EHD4-knockout (KO)] mice on a C57Bl/6 background excreted a higher volume of more dilute urine than control C57Bl/6 wild-type (WT) mice while maintaining a similar plasma osmolality. Urine excretion after an acute intraperitoneal water load was significantly increased in EHD4-KO mice compared to WT mice, and although EHD4-KO mice concentrated their urine during 24-h water restriction, urinary osmolality remained significantly lower than in WT mice, suggesting that EHD4 plays a role in renal water handling. Total aquaporin 2 (AQP2) and phospho-S256-AQP2 (pAQP2) protein expression in the inner medulla was similar in the two groups in baseline conditions. However, localization of both AQP2 and pAQP2 in the renal inner medullary principal cells appeared more dispersed, and the intensity of apical membrane staining for AQP2 was reduced significantly (by ∼20%) in EHD4-KO mice compared to WT mice in baseline conditions, suggesting an important role of EHD4 in trafficking of AQP2. Together, these data indicate that EHD4 play important roles in the regulation of water homeostasis.-Rahman, S. S., Moffitt, A. E. J., Trease, A. J., Foster, K. W., Storck, M. D., Band, H., Boesen, E. I. EHD4 is a novel regulator of urinary water homeostasis.
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Affiliation(s)
- Shamma S Rahman
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Alexandra E J Moffitt
- The Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Andrew J Trease
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Kirk W Foster
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Matthew D Storck
- The Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Hamid Band
- The Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, Nebraska, USA; .,Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, USA.,Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA.,Department of Genetics, Cell Biology, and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, USA.,Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, USA; and.,Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Erika I Boesen
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, USA;
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Khositseth S, Charngkaew K, Boonkrai C, Somparn P, Uawithya P, Chomanee N, Payne DM, Fenton RA, Pisitkun T. Hypercalcemia induces targeted autophagic degradation of aquaporin-2 at the onset of nephrogenic diabetes insipidus. Kidney Int 2017; 91:1070-1087. [PMID: 28139295 DOI: 10.1016/j.kint.2016.12.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 11/16/2016] [Accepted: 12/01/2016] [Indexed: 12/22/2022]
Abstract
Hypercalcemia can cause renal dysfunction such as nephrogenic diabetes insipidus (NDI), but the mechanisms underlying hypercalcemia-induced NDI are not well understood. To elucidate the early molecular changes responsible for this disorder, we employed mass spectrometry-based proteomic analysis of inner medullary collecting ducts (IMCD) isolated from parathyroid hormone-treated rats at onset of hypercalcemia-induced NDI. Forty-one proteins, including the water channel aquaporin-2, exhibited significant changes in abundance, most of which were decreased. Bioinformatic analysis revealed that many of the downregulated proteins were associated with cytoskeletal protein binding, regulation of actin filament polymerization, and cell-cell junctions. Targeted LC-MS/MS and immunoblot studies confirmed the downregulation of 16 proteins identified in the initial proteomic analysis and in additional experiments using a vitamin D treatment model of hypercalcemia-induced NDI. Evaluation of transcript levels and estimated half-life of the downregulated proteins suggested enhanced protein degradation as the possible regulatory mechanism. Electron microscopy showed defective intercellular junctions and autophagy in the IMCD cells from both vitamin D- and parathyroid hormone-treated rats. A significant increase in the number of autophagosomes was confirmed by immunofluorescence labeling of LC3. Colocalization of LC3 and Lamp1 with aquaporin-2 and other downregulated proteins was found in both models. Immunogold electron microscopy revealed aquaporin-2 in autophagosomes in IMCD cells from both hypercalcemia models. Finally, parathyroid hormone withdrawal reversed the NDI phenotype, accompanied by termination of aquaporin-2 autophagic degradation and normalization of both nonphoshorylated and S256-phosphorylated aquaporin-2 levels. Thus, enhanced autophagic degradation of proteins plays an important role in the initial mechanism of hypercalcemic-induced NDI.
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Affiliation(s)
- Sookkasem Khositseth
- Department of Pediatrics, Faculty of Medicine, Thammasat University, Pathumthani, Thailand.
| | - Komgrid Charngkaew
- Department of Pathology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Chatikorn Boonkrai
- Systems Biology Center, Research Affairs, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Poorichaya Somparn
- Systems Biology Center, Research Affairs, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Panapat Uawithya
- Department of Physiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Nusara Chomanee
- Department of Pathology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - D Michael Payne
- Systems Biology Center, Research Affairs, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Robert A Fenton
- Department of Biomedicine and Center for Interactions of Proteins in Epithelial Transport, Aarhus University, Aarhus, Denmark
| | - Trairak Pisitkun
- Systems Biology Center, Research Affairs, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand; Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, Bethesda, Maryland, USA.
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15
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Loh SY, Giribabu N, Salleh N. Effects of gonadectomy and testosterone treatment on aquaporin expression in the kidney of normotensive and hypertensive rats. Exp Biol Med (Maywood) 2017; 242:1376-1386. [PMID: 28399644 DOI: 10.1177/1535370217703360] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
We tested the hypothesis that testosterone-induced increase in blood pressure was due to changes in aquaporin (AQP) expression in kidneys. In this study, expression level of kidney AQPs was investigated under testosterone influence. Adult normotensive Wistar Kyoto (WKY) and hypertensive SHR male and female rats underwent gonadectomy. For female rats, testosterone was given for six weeks duration, two weeks following ovariectomy via subcutaneous silastic implant. Mean arterial pressure (MAP) was measured in all the rats after eight weeks via carotid artery cannulation and the rats were then sacrificed and kidneys were harvested for analyses of AQP-1, 2, 3, 4, 6, and 7 mRNA and protein expressions by quantitative real-time PCR and Western blotting, respectively. Distribution of AQP subunits' protein in kidneys was observed by immunofluorescence. In male WKY rats, MAP, AQP-1, 2, 4, and 7 protein; and mRNA expression decreased however AQP-3 protein and mRNA expression increased following orchidectomy. The vice versa effects were observed in testosterone-treated ovariectomized female WKY rats. However, no changes in AQP-6 expression were observed. Meanwhile, in adult male SHR rats, MAP and expression level of all AQP subunits decreased following orchidectomy. The opposite effects were seen in ovariectomized female SHR rats following testosterone treatment. Immunofluorescence study showed AQP-1 and AQP-7 were distributed in the proximal convoluted tubules (PCT) while AQP-2, AQP-4, and AQP-6 were distributed in the collecting ducts (CDs). AQP-3 was distributed in the PCT and CD. In conclusion, changes in AQP subunit expression in kidneys could explain changes in blood pressure under testosterone influence. Impact statement This study provides fundamental understanding on the mechanisms underlying testosterone-induced increase in blood pressure which involve regulation of aquaporin channel subunits in the kidneys. A better understanding of this issue can help to explain the reason for higher blood pressure in males as compared to females and may explain the reason for higher blood pressure in females after menopause than females before menopause, the former most probably related to the changes in female androgen.
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Affiliation(s)
- Su Yi Loh
- Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Nelli Giribabu
- Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Naguib Salleh
- Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
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16
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Li Y, Wang W, Jiang T, Yang B. Aquaporins in Urinary System. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 969:131-148. [PMID: 28258571 DOI: 10.1007/978-94-024-1057-0_9] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Several aquaporin (AQP )-type water channels are expressed in kidney: AQP1 in the proximal tubule, thin descending limb of Henle, and vasa recta; AQP2 -6 in the collecting duct; AQP7 in the proximal tubule; AQP8 in the proximal tubule and collecting duct; and AQP11 in the endoplasmic reticulum of proximal tubule cells. AQP2 is the vasopressin-regulated water channel that is important in hereditary and acquired diseases affecting urine-concentrating ability. The roles of AQPs in renal physiology and transepithelial water transport have been determined using AQP knockout mouse models. This chapter describes renal physiologic insights revealed by phenotypic analysis of AQP knockout mice and the prospects for further basic and clinical studies.
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Affiliation(s)
- Yingjie Li
- Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, 100191, China
| | - Weiling Wang
- State Key Laboratory of Natural and Biomimetic Drugs, and Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, 100191, China
| | - Tao Jiang
- Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, 100191, China
| | - Baoxue Yang
- Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, 100191, China.
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing, 100191, China.
- Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Peking University, Beijing, 100191, China.
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17
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Miyoshi T, Yamaguchi T, Ogita K, Tanaka Y, Ishibashi KI, Ito H, Kobayashi T, Nakagawa T, Ito J, Omori K, Yamamoto N. Quantitative Analysis of Aquaporin Expression Levels during the Development and Maturation of the Inner Ear. J Assoc Res Otolaryngol 2016; 18:247-261. [PMID: 28004290 DOI: 10.1007/s10162-016-0607-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Accepted: 11/24/2016] [Indexed: 01/30/2023] Open
Abstract
Aquaporins (AQPs) are a family of small membrane proteins that transport water molecules across the plasma membrane along the osmotic gradient. Mammals express 13 subtypes of AQPs, including the recently reported "subcellular AQPs", AQP11 and 12. Each organ expresses specific subsets of AQP subtypes, and in the inner ear, AQPs are essential for the establishment and maintenance of two distinct fluids, endolymph and perilymph. To evaluate the contribution of AQPs during the establishment of inner ear function, we used quantitative reverse transcription polymerase chain reaction to quantify the expression levels of all known AQPs during the entire development and maturation of the inner ear. Using systematic and longitudinal quantification, we found that AQP11 was majorly and constantly expressed in the inner ear, and that the expression levels of several AQPs follow characteristic longitudinal patterns: increasing (Aqp0, 1, and 9), decreasing (Aqp6, 8, and 12), and peak of expression on E18 (Aqp2, 5, and 7). In particular, the expression level of Aqp9 increased by 70-fold during P3-P21. We also performed in situ hybridization of Aqp11, and determined the unique localization of Aqp11 in the outer hair cells. Immunohistochemistry of AQP9 revealed its localization in the supporting cells inside the organ of Corti, and in the root cells. The emergence of AQP9 expression in these cells was during P3-P21, which was coincident with the marked increase of its expression level. Combining these quantification and localization data, we discuss the possible contributions of these AQPs to inner ear function.
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Affiliation(s)
- Takushi Miyoshi
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Kyoto, Japan
| | - Taro Yamaguchi
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Setsunan University, Neyagawa, 572-0074, Osaka, Japan
| | - Kiyokazu Ogita
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Setsunan University, Neyagawa, 572-0074, Osaka, Japan
| | - Yasuko Tanaka
- Department of Medical Physiology, Meiji Pharmaceutical University, Kiyose, 204-0004, Tokyo, Japan
| | - Ken-Ichi Ishibashi
- Department of Medical Physiology, Meiji Pharmaceutical University, Kiyose, 204-0004, Tokyo, Japan
| | - Hiroaki Ito
- Department of Otolaryngology, Head and Neck Surgery, Kochi Medical School, Nangoku, 783-0043, Kochi, Japan
| | - Taisuke Kobayashi
- Department of Otolaryngology, Head and Neck Surgery, Kochi Medical School, Nangoku, 783-0043, Kochi, Japan
| | - Takayuki Nakagawa
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Kyoto, Japan
| | - Juichi Ito
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Kyoto, Japan.,Shiga Medical Center Research Institute, Moriyama, 524-0022, Shiga, Japan
| | - Koichi Omori
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Kyoto, Japan
| | - Norio Yamamoto
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Kyoto, Japan.
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18
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Baturina GS, Katkova LE, Zarogiannis SG, Solenov EI. Brattleboro rats have impaired apical membrane water permeability regulation in the outer medullary collecting duct principal cells. Clin Exp Pharmacol Physiol 2016; 43:1225-1233. [DOI: 10.1111/1440-1681.12666] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Revised: 07/28/2016] [Accepted: 08/31/2016] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Sotirios G Zarogiannis
- Department of Physiology; Faculty of Medicine; University of Thessaly; BIOPOLIS; Larissa Greece
| | - Evgeniy I Solenov
- Institute of Cytology and Genetics, SB RAS; Novosibirsk Russia
- Novosibirsk State University; Novosibirsk Russia
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Arnspang EC, Login FH, Koffman JS, Sengupta P, Nejsum LN. AQP2 Plasma Membrane Diffusion Is Altered by the Degree of AQP2-S256 Phosphorylation. Int J Mol Sci 2016; 17:ijms17111804. [PMID: 27801846 PMCID: PMC5133805 DOI: 10.3390/ijms17111804] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 09/15/2016] [Accepted: 09/22/2016] [Indexed: 01/21/2023] Open
Abstract
Fine tuning of urine concentration occurs in the renal collecting duct in response to circulating levels of arginine vasopressin (AVP). AVP stimulates intracellular cAMP production, which mediates exocytosis of sub-apical vesicles containing the water channel aquaporin-2 (AQP2). Protein Kinase A (PKA) phosphorylates AQP2 on serine-256 (S256), which triggers plasma membrane accumulation of AQP2. This mediates insertion of AQP2 into the apical plasma membrane, increasing water permeability of the collecting duct. AQP2 is a homo-tetramer. When S256 on all four monomers is changed to the phosphomimic aspartic acid (S256D), AQP2-S256D localizes to the plasma membrane and internalization is decreased. In contrast, when S256 is mutated to alanine (S256A) to mimic non-phosphorylated AQP2, AQP2-S256A localizes to intracellular vesicles as well as the plasma membrane, with increased internalization from the plasma membrane. S256 phosphorylation is not necessary for exocytosis and dephosphorylation is not necessary for endocytosis, however, the degree of S256 phosphorylation is hypothesized to regulate the kinetics of AQP2 endocytosis and thus, retention time in the plasma membrane. Using k-space Image Correlation Spectroscopy (kICS), we determined how the number of phosphorylated to non-phosphorylated S256 monomers in the AQP2 tetramer affects diffusion speed of AQP2 in the plasma membrane. When all four monomers mimicked constitutive phosphorylation (AQP2-S256D), diffusion was faster than when all four were non-phosphorylated (AQP2-S256A). AQP2-WT diffused at a speed similar to that of AQP2-S256D. When an average of two or three monomers in the tetramer were constitutively phosphorylated, the average diffusion coefficients were not significantly different to that of AQP2-S256D. However, when only one monomer was phosphorylated, diffusion was slower and similar to AQP2-S256A. Thus, AQP2 with two to four phosphorylated monomers has faster plasma membrane kinetics, than the tetramer which contains just one or no phosphorylated monomers. This difference in diffusion rate may reflect behavior of AQP2 tetramers destined for either plasma membrane retention or endocytosis.
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Affiliation(s)
- Eva C Arnspang
- Department of Clinical Medicine, Aarhus University, DK-8000 Aarhus C, Denmark.
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Frédéric H Login
- Department of Clinical Medicine, Aarhus University, DK-8000 Aarhus C, Denmark.
| | - Jennifer S Koffman
- Department of Interdisciplinary Nanoscience Center, Aarhus University, DK-8000 Aarhus C, Denmark.
| | - Prabuddha Sengupta
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Lene N Nejsum
- Department of Clinical Medicine, Aarhus University, DK-8000 Aarhus C, Denmark.
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20
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Matsuzaki T, Yaguchi T, Shimizu K, Kita A, Ishibashi K, Takata K. The distribution and function of aquaporins in the kidney: resolved and unresolved questions. Anat Sci Int 2016; 92:187-199. [PMID: 26798062 DOI: 10.1007/s12565-016-0325-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 12/31/2015] [Indexed: 11/25/2022]
Abstract
The membrane water channel aquaporin (AQP) family is composed of 13 isoforms in mammals, eight of which are reportedly expressed in the kidney: AQP1, 2, 3, 4, 6, 7, 8, and 11. These isoforms are differentially expressed along the renal tubules and collecting ducts. AQP1 and 7 are distributed in the proximal tubules, whereas AQP2, 3, and 4 occur in the collecting duct system. They play important roles in the reabsorption of water and some solutes across the plasma membrane. In contrast to other aquaporins found in the kidney, AQP6, 8, and 11 are localized to the cytoplasm rather than to the apical or basolateral membranes. It is therefore doubtful that these isoforms are directly involved in water or solute reabsorption. AQP6 is localized in acid-secreting type A intercalated cells of the collecting duct. AQP8 has been found in the proximal tubule but its cellular location has not yet been defined by immunohistochemistry. AQP11 seems to be localized in the endoplasmic reticulum (ER) of proximal tubule cells. Interestingly, polycystic kidneys develop in AQP11-null mice. Many vacuole-like structures are seen in proximal tubule cells in kidneys of newborn AQP11-null mice. Subsequently, cysts are generated, and most of the mice die within a month due to severe renal failure. Although ER stress and impairment of polycystin-1, the product of the gene mutated in autosomal-dominant polycystic kidney disease, are possible causes of cystogenesis in AQP11-null mice, the exact mechanism of pathogenesis and the physiological function of AQP11 are yet to be resolved.
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Affiliation(s)
- Toshiyuki Matsuzaki
- Department of Anatomy and Cell Biology, Gunma University Graduate School of Medicine, Maebashi, Gunma, 371-8511, Japan.
| | - Tomoyuki Yaguchi
- Department of Anatomy and Cell Biology, Gunma University Graduate School of Medicine, Maebashi, Gunma, 371-8511, Japan
| | - Kinue Shimizu
- Department of Anatomy and Cell Biology, Gunma University Graduate School of Medicine, Maebashi, Gunma, 371-8511, Japan
| | - Aoi Kita
- Department of Anatomy and Cell Biology, Gunma University Graduate School of Medicine, Maebashi, Gunma, 371-8511, Japan
| | - Kenichi Ishibashi
- Department of Medical Physiology, Meiji Pharmaceutical University, Kiyose, Tokyo, 204-8588, Japan
| | - Kuniaki Takata
- Gunma Prefectural College of Health Sciences, 323-1 Kamioki-Machi, Maebashi, Gunma, 371-0052, Japan
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21
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Khositseth S, Uawithya P, Somparn P, Charngkaew K, Thippamom N, Hoffert JD, Saeed F, Michael Payne D, Chen SH, Fenton RA, Pisitkun T. Autophagic degradation of aquaporin-2 is an early event in hypokalemia-induced nephrogenic diabetes insipidus. Sci Rep 2015; 5:18311. [PMID: 26674602 PMCID: PMC4682130 DOI: 10.1038/srep18311] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 11/16/2015] [Indexed: 12/19/2022] Open
Abstract
Hypokalemia (low serum potassium level) is a common electrolyte imbalance that can cause a defect in urinary concentrating ability, i.e., nephrogenic diabetes insipidus (NDI), but the molecular mechanism is unknown. We employed proteomic analysis of inner medullary collecting ducts (IMCD) from rats fed with a potassium-free diet for 1 day. IMCD protein quantification was performed by mass spectrometry using a label-free methodology. A total of 131 proteins, including the water channel AQP2, exhibited significant changes in abundance, most of which were decreased. Bioinformatic analysis revealed that many of the down-regulated proteins were associated with the biological processes of generation of precursor metabolites and energy, actin cytoskeleton organization, and cell-cell adhesion. Targeted LC-MS/MS and immunoblotting studies further confirmed the down regulation of 18 selected proteins. Electron microscopy showed autophagosomes/autophagolysosomes in the IMCD cells of rats deprived of potassium for only 1 day. An increased number of autophagosomes was also confirmed by immunofluorescence, demonstrating co-localization of LC3 and Lamp1 with AQP2 and several other down-regulated proteins in IMCD cells. AQP2 was also detected in autophagosomes in IMCD cells of potassium-deprived rats by immunogold electron microscopy. Thus, enhanced autophagic degradation of proteins, most notably including AQP2, is an early event in hypokalemia-induced NDI.
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Affiliation(s)
- Sookkasem Khositseth
- Department of Pediatrics, Faculty of Medicine, Thammasat University Klong Luang, Pathumthani, 12120, Thailand
| | - Panapat Uawithya
- Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University Bangkok, 10700, Thailand
| | - Poorichaya Somparn
- Systems Biology Center, Research Affairs, Faculty of Medicine, Chulalongkorn University 1873 Rama 4 Road, Pathumwan, Bangkok, 10330, Thailand
| | - Komgrid Charngkaew
- Department of Pathology, Faculty of Medicine Siriraj Hospital, Mahidol University Bangkok, 10700, Thailand
| | - Nattakan Thippamom
- Department of Pediatrics, Faculty of Medicine, Thammasat University Klong Luang, Pathumthani, 12120, Thailand
| | - Jason D. Hoffert
- National Institute of Diabetes and Digestive and Kidney, Bethesda MD 20892, United States
| | - Fahad Saeed
- Department of Electrical & Computer Engineering and Department of Computer Science, Western Michigan University Kalamazoo, 49008, United States
| | - D. Michael Payne
- Systems Biology Center, Research Affairs, Faculty of Medicine, Chulalongkorn University 1873 Rama 4 Road, Pathumwan, Bangkok, 10330, Thailand
| | - Shu-Hui Chen
- Department of Chemistry, National Cheng Kung University, Tainan City, 701, Taiwan
| | - Robert A. Fenton
- Department of Biomedicine and Center for Interactions of Proteins in Epithelial Transport, Aarhus University, Aarhus, 8000, Denmark
| | - Trairak Pisitkun
- Systems Biology Center, Research Affairs, Faculty of Medicine, Chulalongkorn University 1873 Rama 4 Road, Pathumwan, Bangkok, 10330, Thailand
- Department of Biomedicine and Center for Interactions of Proteins in Epithelial Transport, Aarhus University, Aarhus, 8000, Denmark
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, Bethesda MD 20892, United States
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22
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Physiological role of aquaporin 5 in salivary glands. Pflugers Arch 2015; 468:519-39. [DOI: 10.1007/s00424-015-1749-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 10/15/2015] [Accepted: 10/16/2015] [Indexed: 12/18/2022]
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23
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Abstract
Desert rodents face a sizeable challenge in maintaining salt and water homeostasis due to their life in an arid environment. A number of their organ systems exhibit functional characteristics that limit water loss above that which occurs in non-desert species under similar conditions. These systems include renal, pulmonary, gastrointestinal, nasal, and skin epithelia. The desert rodent kidney preserves body water by producing a highly concentrated urine that reaches a maximum osmolality nearly three times that of the common laboratory rat. The precise mechanism by which urine is concentrated in any mammal is unknown. Insights into the process may be more apparent in species that produce highly concentrated urine. Aquaporin water channels play a fundamental role in water transport in several desert rodent organ systems. The role of aquaporins in facilitating highly effective water preservation in desert rodents is only beginning to be explored. The organ systems of desert rodents and their associated AQPs are described.
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Affiliation(s)
- Thomas L Pannabecker
- Department of Physiology, AHSC 4128, University of Arizona Health Sciences Center, 1501 N. Campbell Avenue, Tucson, Arizona 85724-5051
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24
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Park EJ, Kwon TH. A Minireview on Vasopressin-regulated Aquaporin-2 in Kidney Collecting Duct Cells. Electrolyte Blood Press 2015; 13:1-6. [PMID: 26240594 PMCID: PMC4520882 DOI: 10.5049/ebp.2015.13.1.1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 06/09/2015] [Indexed: 11/30/2022] Open
Abstract
The kidney collecting duct is an important renal tubular segment for the regulation of body water and salt homeostasis. Water reabsorption in the collecting duct cells is regulated by arginine vasopressin (AVP) via the vasopressin V2-receptor (V2R). AVP increases the osmotic water permeability of the collecting duct cells through aquaporin-2 (AQP2) and aquaporin-3 (AQP3). AVP induces the apical targeting of AQP2 and transcription of AQP2 gene in the kidney collecting duct principal cells. The signaling transduction pathways resulting in the AQP2 trafficking to the apical plasma membrane of the collecting duct principal cells, include AQP2 phosphorylation, RhoA phosphorylation, actin depolymerization and calcium mobilization, and the changes of AQP2 protein abundance in water balance disorders have been extensively studied. These studies elucidate the underlying cellular and molecular mechanisms of body water homeostasis and provide the basis for the treatment of body water balance disorders.
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Affiliation(s)
- Eui-Jung Park
- Department of Biochemistry and Cell Biology, Kyungpook National University School of Medicine, Daegu, Korea
| | - Tae-Hwan Kwon
- Department of Biochemistry and Cell Biology, Kyungpook National University School of Medicine, Daegu, Korea
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25
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26
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AVP-induced increase in AQP2 and p-AQP2 is blunted in heart failure during cardiac remodeling and is associated with decreased AT1R abundance in rat kidney. PLoS One 2015; 10:e0116501. [PMID: 25658446 PMCID: PMC4319737 DOI: 10.1371/journal.pone.0116501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 12/10/2014] [Indexed: 01/02/2023] Open
Abstract
AIM The objective was to examine the renal effects of long-term increased angiotensin II and vasopressin plasma levels in early-stage heart failure (HF). We investigated the regulations of the V2 vasopressin receptor, the type 1A angiotensin II receptor, the (pro)renin receptor, and the water channels AQP2, AQP1, AQP3, and AQP4 in the inner medulla of rat kidney. METHODS HF was induced by coronary artery ligation. Sixty-eight rats were allocated to six groups: Sham (N = 11), HF (N = 11), sodium restricted sham (N = 11), sodium restricted HF (N = 11), sodium restricted sham + DDAVP (N = 12), and sodium restricted HF + DDAVP (N = 12). 1-desamino-8-D-arginine vasopressin (0.5 ng h-1 for 7 days) or vehicle was administered. Pre- and post-treatment echocardiographic evaluation was performed. The rats were sacrificed at day 17 after surgery, before cardiac remodeling in rat is known to be completed. RESULTS HF rats on standard sodium diet and sodium restriction displayed biochemical markers of HF. These rats developed hyponatremia, hypo-osmolality, and decreased fractional excretion of sodium. Increase of AQP2 and p(Ser256)-AQP2 abundance in all HF groups was blunted compared with control groups even when infused with DDAVP and despite increased vasopressin V2 receptor and Gsα abundance. This was associated with decreased protein abundance of the AT1A receptor in HF groups vs. controls. CONCLUSION Early-stage HF is associated with blunted increase in AQP2 and p(Ser256)-AQP2 despite of hyponatremia, hypo-osmolality, and increased inner medullary vasopressin V2 receptor expression. Decreased type 1A angiotensin II receptor abundance likely plays a role in the transduction of these effects.
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27
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Pearce D, Soundararajan R, Trimpert C, Kashlan OB, Deen PM, Kohan DE. Collecting duct principal cell transport processes and their regulation. Clin J Am Soc Nephrol 2015; 10:135-46. [PMID: 24875192 PMCID: PMC4284417 DOI: 10.2215/cjn.05760513] [Citation(s) in RCA: 198] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The principal cell of the kidney collecting duct is one of the most highly regulated epithelial cell types in vertebrates. The effects of hormonal, autocrine, and paracrine factors to regulate principal cell transport processes are central to the maintenance of fluid and electrolyte balance in the face of wide variations in food and water intake. In marked contrast with the epithelial cells lining the proximal tubule, the collecting duct is electrically tight, and ion and osmotic gradients can be very high. The central role of principal cells in salt and water transport is reflected by their defining transporters-the epithelial Na(+) channel (ENaC), the renal outer medullary K(+) channel, and the aquaporin 2 (AQP2) water channel. The coordinated regulation of ENaC by aldosterone, and AQP2 by arginine vasopressin (AVP) in principal cells is essential for the control of plasma Na(+) and K(+) concentrations, extracellular fluid volume, and BP. In addition to these essential hormones, additional neuronal, physical, and chemical factors influence Na(+), K(+), and water homeostasis. Notably, a variety of secreted paracrine and autocrine agents such as bradykinin, ATP, endothelin, nitric oxide, and prostaglandin E2 counterbalance and limit the natriferic effects of aldosterone and the water-retaining effects of AVP. Considerable recent progress has improved our understanding of the transporters, receptors, second messengers, and signaling events that mediate principal cell responses to changing environments in health and disease. This review primarily addresses the structure and function of the key transporters and the complex interplay of regulatory factors that modulate principal cell ion and water transport.
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Affiliation(s)
- David Pearce
- Division of Nephrology, Department of Medicine, University of California, San Francisco, California
| | - Rama Soundararajan
- Department of Translational Molecular Pathology, MD Anderson Cancer Center, Houston, Texas
| | - Christiane Trimpert
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ossama B. Kashlan
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Peter M.T. Deen
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Donald E. Kohan
- Division of Nephrology, University of Utah Health Sciences Center, Salt Lake City, Utah
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Ontogeny of the mammalian kidney: expression of aquaporins 1, 2, 3, and 4. World J Pediatr 2014; 10:306-12. [PMID: 25515803 DOI: 10.1007/s12519-014-0508-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 07/21/2014] [Indexed: 12/16/2022]
Abstract
BACKGROUND Determining the expression and functions of aquaporins (AQPs) in the adult kidney has generated important information about the roles of this protein family in the renal regulation of water homeostasis. However, limited information describes the expression of AQPs in fetal kidneys, and most reports on fetal renal AQPs originate from animal studies. Although there are the maturation and regulation of the renal-concentrating mechanism, the ways in which changes in the expression of AQPs contribute to the formation of urine during the perinatal period remain unclear. DATA SOURCES This review summarizes current knowledge about the spatial and temporal expression patterns of AQP1, AQP2, AQP3, and AQP4 in the fetal and postnatal kidneys in different animal species and in human beings. RESULTS AQP1 and AQP2 expression can be detected earlier in gestation in human beings and sheep compared with mice and rats. AQP1 expression is detected earlier in the proximal tubules than the expression of AQP2, AQP3, and AQP4 in the collecting ducts. CONCLUSION Further studies investigating the regulation of AQPs during kidney development may provide insights into normal water-handling mechanisms and the pathophysiology of fetal kidneys, which may determine new directions for the clinical treatment of kidney diseases.
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Marlar S, Arnspang EC, Koffman JS, Løcke EM, Christensen BM, Nejsum LN. Elevated cAMP increases aquaporin-3 plasma membrane diffusion. Am J Physiol Cell Physiol 2014; 306:C598-606. [PMID: 24452376 DOI: 10.1152/ajpcell.00132.2013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Regulated urine concentration takes place in the renal collecting duct upon arginine vasopressin (AVP) stimulation, where subapical vesicles containing aquaporin-2 (AQP2) are inserted into the apical membrane instantly increasing water reabsorption and urine concentration. The reabsorped water exits via basolateral AQP3 and AQP4. Upon long-term stimulation with AVP or during thirst, expression levels of both AQP2 and AQP3 are increased; however, there is so far no evidence for short-term AVP regulation of AQP3 or AQP4. To facilitate the increase in transepithelial water transport, AQP3 may be short-term regulated via changes in protein-protein interactions, incorporation into lipid rafts, and/or changes in steady-state turnover, which could result in changes in the diffusion behavior of AQP3. Thus we measured AQP3 diffusion coefficients upon stimulation with the AVP mimic forskolin to reveal if AQP3 could be short-term regulated by AVP. k-Space image correlation spectroscopy (kICS) analysis of time-lapse image sequences of basolateral enhanced green fluorescent protein-tagged AQP3 (AQP3-EGFP) revealed that the forskolin-mediated elevation of cAMP increased the diffusion coefficient by 58% from 0.0147 ± 0.0082 μm(2)/s (control) to 0.0232 ± 0.0085 μm(2)/s (forskolin, P < 0.05). Quantum dot-conjugated antibody labeling also revealed a significant increase in AQP3 diffusion upon forskolin treatment by 44% [0.0104 ± 0.0040 μm(2)/s (control) vs. 0.0150 ± 0.0016 μm(2)/s (forskolin, P < 0.05)]. Immunoelectron microscopy showed no obvious difference in AQP3-EGFP expression levels or localization in the plasma membrane upon forskolin stimulation. Thus AQP3-EGFP diffusion is altered upon increased cAMP, which may correspond to basolateral adaptations in response to the increased apical water readsorption.
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Affiliation(s)
- Saw Marlar
- Institute of Molecular Biology and Genetics and Interdisciplinary Nanoscience Center, Aarhus University, Aarhus, Denmark; and
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Abstract
Aquaporins (AQPs) are a family of membrane water channels that basically function as regulators of intracellular and intercellular water flow. To date, thirteen aquaporins have been characterized. They are distributed wildly in specific cell types in multiple organs and tissues. Each AQP channel consists of six membrane-spanning alpha-helices that have a central water-transporting pore. Four AQP monomers assemble to form tetramers, which are the functional units in the membrane. Some of AQPs also transport urea, glycerol, ammonia, hydrogen peroxide, and gas molecules. AQP-mediated osmotic water transport across epithelial plasma membranes facilitates transcellular fluid transport and thus water reabsorption. AQP-mediated urea and glycerol transport is involved in energy metabolism and epidermal hydration. AQP-mediated CO2 and NH3 transport across membrane maintains intracellular acid-base homeostasis. AQPs are also involved in the pathophysiology of a wide range of human diseases (including water disbalance in kidney and brain, neuroinflammatory disease, obesity, and cancer). Further work is required to determine whether aquaporins are viable therapeutic targets or reliable diagnostic and prognostic biomarkers.
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Kortenoeven MLA, Fenton RA. Renal aquaporins and water balance disorders. Biochim Biophys Acta Gen Subj 2013; 1840:1533-49. [PMID: 24342488 DOI: 10.1016/j.bbagen.2013.12.002] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 11/26/2013] [Accepted: 12/09/2013] [Indexed: 12/17/2022]
Abstract
BACKGROUND Aquaporins (AQPs) are a family of proteins that can act as water channels. Regulation of AQPs is critical to osmoregulation and the maintenance of body water homeostasis. Eight AQPs are expressed in the kidney of which five have been shown to play a role in body water balance; AQP1, AQP2, AQP3, AQP4 and AQP7. AQP2 in particular is regulated by vasopressin. SCOPE OF REVIEW This review summarizes our current knowledge of the underlying mechanisms of various water balance disorders and their treatment strategies. MAJOR CONCLUSIONS Dysfunctions of AQPs are involved in disorders associated with disturbed water homeostasis. Hyponatremia with increased AQP levels can be caused by diseases with low effective circulating blood volume, such as congestive heart failure, or osmoregulation disorders such as the syndrome of inappropriate secretion of antidiuretic hormone. Treatment consists of fluid restriction, demeclocycline and vasopressin type-2 receptor antagonists. Decreased AQP levels can lead to diabetes insipidus (DI), characterized by polyuria and polydipsia. In central DI, vasopressin production is impaired, while in gestational DI, levels of the vasopressin-degrading enzyme vasopressinase are abnormally increased. Treatment consists of the vasopressin analogue dDAVP. Nephrogenic DI is caused by the inability of the kidney to respond to vasopressin and can be congenital, but is most commonly acquired, usually due to lithium therapy. Treatment consists of sufficient fluid supply, low-solute diet and diuretics. GENERAL SIGNIFICANCE In recent years, our understanding of the underlying mechanisms of water balance disorders has increased enormously, which has opened up several possible new treatment strategies. This article is part of a Special Issue entitled Aquaporins.
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Affiliation(s)
- Marleen L A Kortenoeven
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; Center for Interactions of Proteins in Epithelial Transport (InterPrET), Aarhus University, Aarhus, Denmark.
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; Center for Interactions of Proteins in Epithelial Transport (InterPrET), Aarhus University, Aarhus, Denmark.
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Aquaporin-3 and aquaporin-4 are sorted differently and separately in the trans-Golgi network. PLoS One 2013; 8:e73977. [PMID: 24058510 PMCID: PMC3776795 DOI: 10.1371/journal.pone.0073977] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 08/01/2013] [Indexed: 11/19/2022] Open
Abstract
Aquaporin-3 (AQP3) and aquaporin-4 (AQP4) are homologous proteins expressed in the basolateral plasma membrane of kidney collecting duct principal cells, where they mediate the exit pathway for apically reabsorbed water. Although both proteins are localized to the same plasma membrane domain, it is unknown if they are sorted together in the Golgi, or arrive in the same or different vesicles at the plasma membrane. We addressed these questions using high resolution deconvolution imaging, spinning disk and laser scanning confocal microscopy of cells expressing AQP3 and AQP4. AQP3 and AQP4 were observed mostly in separate post-Golgi carriers, and spinning disk microscopy showed that most of AQP3 and AQP4 were delivered to the plasma membrane in separate vesicles. In contrast, VSV-G and LDL-R, two well-charcterized basolateral proteins, co-localized to a high degree in the same post-Golgi carriers, indicating that the differential sorting of AQP3 and AQP4 is specific and regulated. Significantly, a chimeric AQP3 containing the AQP4 cytoplasmic tails co-localized with AQP4 in post-Golgi vesicles. These results indicate that AQP3 and AQP4 are separated into different post-Golgi carriers based on different cytoplasmic domain sorting signals, and are then delivered separately to the plasma membrane.
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Poulsen SB, Kim YH, Frøkiær J, Nielsen S, Christensen BM. Long-term vasopressin-V2-receptor stimulation induces regulation of aquaporin 4 protein in renal inner medulla and cortex of Brattleboro rats. Nephrol Dial Transplant 2013; 28:2058-65. [DOI: 10.1093/ndt/gft088] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Pannabecker TL. Comparative physiology and architecture associated with the mammalian urine concentrating mechanism: role of inner medullary water and urea transport pathways in the rodent medulla. Am J Physiol Regul Integr Comp Physiol 2013; 304:R488-503. [PMID: 23364530 PMCID: PMC3627947 DOI: 10.1152/ajpregu.00456.2012] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 01/25/2013] [Indexed: 01/07/2023]
Abstract
Comparative studies of renal structure and function have potential to provide insights into the urine-concentrating mechanism of the mammalian kidney. This review focuses on the tubular transport pathways for water and urea that play key roles in fluid and solute movements between various compartments of the rodent renal inner medulla. Information on aquaporin water channel and urea transporter expression has increased our understanding of functional segmentation of medullary thin limbs of Henle's loops, collecting ducts, and vasa recta. A more complete understanding of membrane transporters and medullary architecture has identified new and potentially significant interactions between these structures and the interstitium. These interactions are now being introduced into our concept of how the inner medullary urine-concentrating mechanism works. A variety of regulatory pathways lead directly or indirectly to variable patterns of fluid and solute movements among the interstitial and tissue compartments. Animals with the ability to produce highly concentrated urine, such as desert species, are considered to exemplify tubular structure and function that optimize urine concentration. These species may provide unique insights into the urine-concentrating process.(1)
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Affiliation(s)
- Thomas L Pannabecker
- Department of Physiology, AHSC 4128, University of Arizona Health Sciences Center, 1501 N. Campbell Ave., Tucson, AZ 85724-5051, USA.
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Li ZZ, Xing L, Zhao ZZ, Li JS, Xue R, Chandra A, Nørregaard R, Wen JG. Decrease of renal aquaporins 1-4 is associated with renal function impairment in pediatric congenital hydronephrosis. World J Pediatr 2012; 8:335-41. [PMID: 23151861 DOI: 10.1007/s12519-012-0378-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2011] [Accepted: 04/23/2012] [Indexed: 11/29/2022]
Abstract
BACKGROUND Renal aquaporins (AQP1-4) concentration is downregulated and is in proportion to the degree of hydronephrosis graded by ultrasound in pediatric congenital hydronephrosis (CH). However, the relationship between the expression of AQP1-4 with the changes of renal function impairment (RFI) evaluated by (99m)Tc-DTPA renal dynamic imaging is still unclear. This study aimed to investigate the relationship between AQP1-4 expression and degree of RFI in children with CH. METHODS The expression of AQP1-4 was evaluated in 45 children with unilateral ureteropelvic junction obstruction (28 boys and 17 girls, average age: 28±10 months) and 15 children undergoing nephrectomy for nephroblastoma (8 boys and 7 girls, average age: 26±8 months) by immunoblotting and immunohistochemistry. Renal function was graded into mild and severe RFI by (99m)Tc-DTPA renal dynamic imaging. RESULTS One-way analysis of variance with Bonferonni's correction showed a significantly reduced protein expression of AQP1-4 in the severe RFI group compared with those in both mild RFI group and controls (AQP1: 0.52±0.09 vs. 0.91±0.06 vs. 1.23±0.033; AQP2: 0.68±0.12 vs. 1.09±0.06 vs. 1.52±0.08; AQP3: 0.59±0.16 vs. 0.94±0.08 vs. 1.31±0.07; AQP4: 0.64±0.06 vs. 1.14±0.07 vs. 1.61±0.07; P<0.001, respectively). In kidneys with severe RFI, there was a reduction in the protein concentration of all four AQP isoforms which was more pronounced compared with those seen in kidneys with mild RFI and in the controls. CONCLUSION AQP1-4 expression is reduced in proportion with the impairment degree of renal function graded by (99m)Tc-DTPA renal dynamic imaging in human CH.
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Affiliation(s)
- Zhen-Zhen Li
- The Institute of Clinical Medicine, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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Water channel proteins in the inner ear and their link to hearing impairment and deafness. Mol Aspects Med 2012; 33:612-37. [DOI: 10.1016/j.mam.2012.06.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 06/11/2012] [Accepted: 06/17/2012] [Indexed: 11/24/2022]
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Langaa S, Bloksgaard M, Bek S, Neess D, Nørregaard R, Hansen PBL, Marcher AB, Frøkiær J, Mandrup S, Jensen BL. Mice with targeted disruption of the acyl-CoA binding protein display attenuated urine concentrating ability and diminished renal aquaporin-3 abundance. Am J Physiol Renal Physiol 2012; 302:F1034-44. [DOI: 10.1152/ajprenal.00371.2011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The acyl-CoA binding protein (ACBP) is a small intracellular protein that specifically binds and transports medium to long-chain acyl-CoA esters. Previous studies have shown that ACBP is ubiquitously expressed but found at particularly high levels in lipogenic cell types as well as in many epithelial cells. Here we show that ACBP is widely expressed in human and mouse kidney epithelium, with the highest expression in the proximal convoluted tubules. To elucidate the role of ACBP in the renal epithelium, mice with targeted disruption of the ACBP gene (ACBP−/−) were used to study water and NaCl balance as well as urine concentrating ability in metabolic cages. Food intake and urinary excretion of Na+ and K+ did not differ between ACBP−/− and +/+ mice. Interestingly, however, water intake and diuresis were significantly higher at baseline in ACBP−/− mice compared with that of +/+ mice. Subsequent to 20-h water deprivation, ACBP−/− mice exhibited increased diuresis, reduced urine osmolality, elevated hematocrit, and higher relative weight loss compared with +/+ mice. There were no significant differences in plasma concentrations of renin, corticosterone, and aldosterone between mice of the two genotypes. After water deprivation, renal medullary interstitial fluid osmolality and concentrations of Na+, K+, and urea did not differ between genotypes and cAMP excretion was similar. Renal aquaporin-1 (AQP1), -2, and -4 protein abundances did not differ between water-deprived +/+ and ACBP−/− mice; however, ACBP−/− mice displayed increased apical targeting of pS256-AQP2. AQP3 abundance was lower in ACBP−/− mice than in +/+ control animals. Thus we conclude that ACBP is necessary for intact urine concentrating ability. Our data suggest that the deficiency in urine concentrating ability in the ACBP−/− may be caused by reduced AQP3, leading to impaired efflux over the basolateral membrane of the collecting duct.
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Affiliation(s)
- Stine Langaa
- Departments of 1Cardiovascular and Renal Research and
| | - Maria Bloksgaard
- Biochemistry and Molecular Biology, University of Southern Denmark, Odense; and
| | - Signe Bek
- Biochemistry and Molecular Biology, University of Southern Denmark, Odense; and
| | - Ditte Neess
- Biochemistry and Molecular Biology, University of Southern Denmark, Odense; and
| | - Rikke Nørregaard
- The Water and Salt Research Center, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | | | - Ann Britt Marcher
- Biochemistry and Molecular Biology, University of Southern Denmark, Odense; and
| | - Jørgen Frøkiær
- The Water and Salt Research Center, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Susanne Mandrup
- Biochemistry and Molecular Biology, University of Southern Denmark, Odense; and
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Abstract
MicroRNAs (miRNAs) are endogenous short (20-22 nucleotides) non-coding RNA molecules that mediate gene expression. This is an important regulatory mechanism to modulate fundamental cellular processes such as differentiation, proliferation, death, metabolism, and pathophysiology of many diseases. The miRNA expression profile of the kidney differs greatly from that of other organs, as well as between the different regions in the kidney. In kidneys, miRNAs are indispensable for development and homeostasis. In this review, we explore the involvement of miRNAs in the regulation of blood pressure, hormone, water, and ion balance pertaining to kidney homeostasis. We also highlight their importance in renal pathophysiology, such as in polycystic disease, diabetic nephropathy, nephrogenic diabetes insipidus, hypertension, renal cancer, and kidney fibrosis (epithelial-mesenchymal transition). In addition, we highlight the need for further investigations on miRNA-based studies in the development of diagnostic, prognostic, and therapeutic tools for renal diseases.
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Kim SW, Gresz V, Rojek A, Wang W, Verkman AS, Frøkiaer J, Nielsen S. Decreased expression of AQP2 and AQP4 water channels and Na, K-ATPase in kidney collecting duct in AQP3 null mice. Biol Cell 2012; 97:765-78. [PMID: 15898956 DOI: 10.1042/bc20040148] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND INFORMATION Phenotype analysis has demonstrated that AQP3 (aquaporin 3) null mice are polyuric and manifest a urinary concentration defect. In the present study, we report that deletion of AQP3 is also associated with an increased urinary sodium excretion. To investigate further the mechanism of the decreased urinary concentration and significant natriuresis, we examined the segmental and subcellular localization of collecting duct AQPs [AQP2, p-AQP2 (phosphorylated AQP2), AQP3 and AQP4], ENaC (epithelial sodium channel) subunits and Na,K-ATPase by immunoperoxidase and immunofluorescence microscopy in AQP3 null (-/-), heterozygous (+/-) mice, wild-type and unrelated strain of normal mice. RESULTS The present study confirms that AQP3 null mice exhibit severe polyuria and polydipsia and demonstrated that they exhibit increased urinary sodium excretion. In AQP3 null mice, there is a marked down-regulation of AQP2 and p-AQP2 both in CNT (connecting tubule) and CCD (cortical collecting duct). Moreover, AQP4 is virtually absent from CNT and CCD in AQP3 null mice. Basolateral AQP2 was virtually absent from AQP3 null mice and normal mice in contrast with rat. Thus the above results demonstrate that no basolateral AQPs are expressed in CNT and CCD of AQP3 null mice. However, in the medullary-collecting ducts, there is no difference in the expression levels and subcellular localization of AQP2, p-AQP2 and AQP4 between AQP3 +/- and AQP3 null mice. Moreover, a striking decrease in the immunolabelling of the alpha1 subunit of Na,K-ATPase was observed in CCD in AQP3 null mice, whereas a medullary-collecting duct exhibited normal labelling. Immunolabelling of all the ENaC subunits in the collecting duct was comparable between the two groups. CONCLUSIONS The results improve the possibility that the severe urinary concentrating defect in AQP3 null mice may in part be caused by the decreased expression of AQP2, p-AQP2 and AQP4 in CNT and CCD, whereas the increased urinary sodium excretion may in part be accounted for by Na,K-ATPase in CCD in AQP3 null mice.
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Affiliation(s)
- Soo Wan Kim
- Water and Salt Research Center, University of Aarhus, DK-8000 Aarhus C, Denmark
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Fenton RA, Praetorius J. Molecular Physiology of the Medullary Collecting Duct. Compr Physiol 2011; 1:1031-56. [DOI: 10.1002/cphy.c100064] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Li JH, Chou CL, Li B, Gavrilova O, Eisner C, Schnermann J, Anderson SA, Deng CX, Knepper MA, Wess J. A selective EP4 PGE2 receptor agonist alleviates disease in a new mouse model of X-linked nephrogenic diabetes insipidus. J Clin Invest 2010; 119:3115-26. [PMID: 19729836 DOI: 10.1172/jci39680] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2009] [Accepted: 07/01/2009] [Indexed: 11/17/2022] Open
Abstract
X-linked nephrogenic diabetes insipidus (XNDI) is a severe kidney disease caused by inactivating mutations in the V2 vasopressin receptor (V2R) gene that result in the loss of renal urine-concentrating ability. At present,no specific pharmacological therapy has been developed for XNDI, primarily due to the lack of suitable animal models. To develop what we believe to be the first viable animal model of XNDI, we generated mice in which the V2R gene could be conditionally deleted during adulthood by administration of 4-OH-tamoxifen.Radioligand-binding studies confirmed the lack of V2R-binding sites in kidneys following 4-OH-tamoxifen treatment, and further analysis indicated that upon V2R deletion, adult mice displayed all characteristic symptoms of XNDI, including polyuria, polydipsia, and resistance to the antidiuretic actions of vasopressin. Gene expression analysis suggested that activation of renal EP4 PGE2 receptors might compensate for the lack of renal V2R activity in XNDI mice. Strikingly, both acute and chronic treatment of the mutant mice with a selective EP4 receptor agonist greatly reduced all major manifestations of XNDI, including changes in renal morphology.These physiological improvements were most likely due to a direct action on EP4 receptors expressed on collecting duct cells. These findings illustrate the usefulness of the newly generated V2R mutant mice for elucidating and testing new strategies for the potential treatment of humans with XNDI.
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Affiliation(s)
- Jian Hua Li
- Molecular Signaling Section, National Institute of Diabetes and Digestive and Kidney Diseases,NIH, Bethesda, Maryland, USA
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Kida H, Miyoshi T, Manabe K, Takahashi N, Konno T, Ueda S, Chiba T, Shimizu T, Okada Y, Morishima S. Roles of aquaporin-3 water channels in volume-regulatory water flow in a human epithelial cell line. J Membr Biol 2009; 208:55-64. [PMID: 16596446 DOI: 10.1007/s00232-005-0819-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2005] [Revised: 11/10/2005] [Indexed: 10/24/2022]
Abstract
Membrane water transport is an essential event not only in the osmotic cell volume change but also in the subsequent cell volume regulation. Here we investigated the route of water transport involved in the regulatory volume decrease (RVD) that occurs after osmotic swelling in human epithelial Intestine 407 cells. The diffusion water permeability coefficient (Pd) measured by NMR under isotonic conditions was much smaller than the osmotic water permeability coefficient (Pf) measured under an osmotic gradient. Temperature dependence of Pf showed the Arrhenius activation energy (Ea) of a low value (1.6 kcal/mol). These results indicate an involvement of a facilitated diffusion mechanism in osmotic water transport. A mercurial water channel blocker (HgCl(2)) diminished the Pf value. A non-mercurial sulfhydryl reagent (MMTS) was also effective. These blockers of water channels suppressed the RVD. RT-PCR and immunocytochemistry demonstrated predominant expression of AQP3 water channel in this cell line. Downregulation of AQP3 expression induced by treatment with antisense oligodeoxynucleotides was found to suppress the RVD response. Thus, it is concluded that AQP3 water channels serve as an essential pathway for volume-regulatory water transport in, human epithelial cells.
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Affiliation(s)
- H Kida
- Department of Cell Physiology, National Institute for Physiological Sciences, Okazaki 444-8585, Japan
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Aquaporin-4 expression is increased in edematous meningiomas. J Clin Neurosci 2009; 16:441-3. [DOI: 10.1016/j.jocn.2008.04.028] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Revised: 04/18/2008] [Accepted: 04/21/2008] [Indexed: 11/22/2022]
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Affiliation(s)
- Tae-Hwan Kwon
- Water and Salt Research Center, Institute of Anatomy, University of Aarhus, 8000 Aarhus C, Denmark
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Abstract
Knockout mice have been informative in the discovery of unexpected biological functions of aquaporins. Knockout mice have confirmed the predicted roles of aquaporins in transepithelial fluid transport, as in the urinary concentrating mechanism and glandular fluid secretion. A less obvious, though predictable role of aquaporins is in tissue swelling under stress, as in the brain in stroke, tumor and infection. Phenotype analysis of aquaporin knockout mice has revealed several unexpected cellular roles of aquaporins whose mechanisms are being elucidated. Aquaporins facilitate cell migration, as seen in aquaporin-dependent tumor angiogenesis and tumor metastasis, by a mechanism that may involve facilitated water transport in lamellipodia of migrating cells. The ' aquaglyceroporins', aquaporins that transport both glycerol and water, regulate glycerol content in epidermis, fat and other tissues, and lead to a multiplicity of interesting consequences of gene disruption including dry skin, resistance to skin carcinogenesis, impaired cell proliferation and altered fat metabolism. An even more surprising role of a mammalian aquaporin is in neural signal transduction in the central nervous system. The many roles of aquaporins might be exploited for clinical benefit by modulation of aquaporin expression/function - as diuretics, and in the treatment of brain swelling, glaucoma, epilepsy, obesity and cancer.
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Affiliation(s)
- Alan S Verkman
- Departments of Medicine and Physiology, Cardiovascular Research Institute, University of California, San Francisco, CA, 94143-0521, USA.
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Abstract
Transgenic mice lacking renal aquaporins (AQPs), or containing mutated AQPs, have been useful in confirming anticipated AQP functions in renal physiology and in discovering new functions. Mice lacking AQPs 1-4 manifest defects in urinary concentrating ability to different extents. Mechanistic studies have confirmed the involvement of AQP1 in near-isosmolar fluid absorption in the proximal tubule, and in countercurrent multiplication and exchange mechanisms that produce medullary hypertonicity in the antidiuretic kidney. Deletion of AQPs 2-4 impairs urinary concentrating ability by reduction of transcellular water permeability in the collecting duct. Recently created transgenic mouse models of nephrogenic diabetes insipidus produced by AQP2 gene mutation offer exciting possibilities to test new drug therapies. Several unanticipated AQP functions in kidney have been discovered recently that are unrelated to their role in transcellular water transport. There is evidence for involvement of AQP1 in kidney cell migration after renal injury, of AQP7 in renal glycerol clearance, of AQP11 in prevention of renal cystic disease, and possibly of AQP3 in regulation of collecting duct cell proliferation. Future work in renal AQPs will focus on mechanisms responsible for these non-fluid-transporting functions, and on the development of small-molecule AQP inhibitors for use as aquaretic-type diuretics.
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Sugiura K, Aste N, Fujii M, Shimada K, Saito N. Effect of hyperosmotic stimulation on aquaporins gene expression in chick kidney. Comp Biochem Physiol A Mol Integr Physiol 2008; 151:173-9. [PMID: 18621138 DOI: 10.1016/j.cbpa.2008.06.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Revised: 06/18/2008] [Accepted: 06/19/2008] [Indexed: 10/21/2022]
Abstract
Birds can produce hyperosmotic urine, but their renal morphology differs from that of mammals. Recent studies in mammals, suggested that various aquaporins (AQPs) are present in the kidney and play crucial roles in urine production. To elucidate the role of AQPs in the avian kidney, we first examined for the presence of AQP1, 2, 3, 4, 7 and 9 mRNAs in the chick (Gallus gallus) kidney by RT-PCR analysis. Next, we quantified variations of AQPs mRNAs levels in chick kidney after hyperosmotic stimulation (water-deprivation or salt-loading) by real-time RT-PCR analysis. Our study showed that in addition to AQP1, 2, 3, 4 and 7, chick kidney also expressed AQP9 and that hyperosmotic stimulation induced changes in AQPs expression. In particular, water-deprivation increased AQP2 and AQP3 mRNAs levels, whereas salt-loading induced a significant increase in AQP1, AQP2 and AQP9 mRNAs levels. AQP4 and AQP7 mRNA levels were not affected by any hyperosmotic stimulation. Taken together, these results indicated that the presence of AQPs in chick kidney is similar to that in mammals, that the chick kidney has an additional AQP9 and that AQP1, 2, 3 and 9 may play a crucial but different role in water permeability in this organ.
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Affiliation(s)
- K Sugiura
- Laboratory of Animal Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
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Mammalian aquaporins: diverse physiological roles and potential clinical significance. Expert Rev Mol Med 2008; 10:e13. [PMID: 18482462 DOI: 10.1017/s1462399408000690] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Aquaporins have multiple distinct roles in mammalian physiology. Phenotype analysis of aquaporin-knockout mice has confirmed the predicted role of aquaporins in osmotically driven transepithelial fluid transport, as occurs in the urinary concentrating mechanism and glandular fluid secretion. Aquaporins also facilitate water movement into and out of the brain in various pathologies such as stroke, tumour, infection and hydrocephalus. A major, unexpected cellular role of aquaporins was revealed by analysis of knockout mice: aquaporins facilitate cell migration, as occurs in angiogenesis, tumour metastasis, wound healing, and glial scar formation. Another unexpected role of aquaporins is in neural function - in sensory signalling and seizure activity. The water-transporting function of aquaporins is likely responsible for these roles. A subset of aquaporins that transport both water and glycerol, the 'aquaglyceroporins', regulate glycerol content in epidermal, fat and other tissues. Mice lacking various aquaglyceroporins have several interesting phenotypes, including dry skin, resistance to skin carcinogenesis, impaired cell proliferation, and altered fat metabolism. The various roles of aquaporins might be exploited clinically by development of drugs to alter aquaporin expression or function, which could serve as diuretics, and in the treatment of brain swelling, glaucoma, epilepsy, obesity and cancer.
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Fenton RA, Knepper MA. Mouse models and the urinary concentrating mechanism in the new millennium. Physiol Rev 2007; 87:1083-112. [PMID: 17928581 DOI: 10.1152/physrev.00053.2006] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Our understanding of urinary concentrating and diluting mechanisms at the end of the 20th century was based largely on data from renal micropuncture studies, isolated perfused tubule studies, tissue analysis studies and anatomical studies, combined with mathematical modeling. Despite extensive data, several key questions remained to be answered. With the advent of the 21st century, a new approach, transgenic and knockout mouse technology, is providing critical new information about urinary concentrating processes. The central goal of this review is to summarize findings in transgenic and knockout mice pertinent to our understanding of the urinary concentrating mechanism, focusing chiefly on mice in which expression of specific renal transporters or receptors has been deleted. These include the major renal water channels (aquaporins), urea transporters, ion transporters and channels (NHE3, NKCC2, NCC, ENaC, ROMK, ClC-K1), G protein-coupled receptors (type 2 vasopressin receptor, prostaglandin receptors, endothelin receptors, angiotensin II receptors), and signaling molecules. These studies shed new light on several key questions concerning the urinary concentrating mechanism including: 1) elucidation of the role of water absorption from the descending limb of Henle in countercurrent multiplication, 2) an evaluation of the feasibility of the passive model of Kokko-Rector and Stephenson, 3) explication of the role of inner medullary collecting duct urea transport in water conservation, 4) an evaluation of the role of tubuloglomerular feedback in maintenance of appropriate distal delivery rates for effective regulation of urinary water excretion, and 5) elucidation of the importance of water reabsorption in the connecting tubule versus the collecting duct for maintenance of water balance.
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Affiliation(s)
- Robert A Fenton
- Water and Salt Research Center, Institute of Anatomy, University of Aarhus, Aarhus, Denmark.
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Maeda S, Kuwahara S, Ito H, Tanaka K, Hayakawa T, Seki M. Expression and localization of aquaporins in the kidney of the musk shrew (Suncus murinus). J Histochem Cytochem 2007; 56:67-75. [PMID: 17938283 DOI: 10.1369/jhc.7a7281.2007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Expression and localization of members of the aquaporin (AQP) family (AQP1, 2, 3, 4, and 5) in the kidney of the musk shrew (Suncus murinus) was examined by immunohistochemistry. AQP1 was expressed in the proximal tubules and in the thin limb of the loops of Henle. AQP1 was the only water channel expressed in the proximal nephron examined, indicating that AQP1 may be an independent water transporter in the proximal nephron. AQP2 and AQP5 were localized to the apical cytoplasm of the cortical to medullary collecting duct (CD) cells and AQP3 and AQP4 were localized to the basal aspect of the cortical to medullary CD cells. AQP3 expression was weaker in the cortical cells compared with the medullary cells, whereas AQP4 was strongly positive throughout the CD. These indicate that the CD is the main water reabsorption segment of the nephron and is regulated by AQPs. Indeed, apical water transport of CD cells of the musk shrew may be controlled by both AQP2 and AQP5. The characteristic expression pattern of the AQPs in this animal provides a novel animal model for elucidating the regulation of water reabsorption by AQPs in the mammalian kidney.
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Affiliation(s)
- Seishi Maeda
- Department of Anatomy, Hyogo College of Medicine, Mukogawa 1-1, Nishinomiya, Hyogo 663-8501, Japan.
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