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Li N, Zhang H, Wang S, Xu Y, Ying Y, Li J, Li X, Li M, Yang B. Urea transporter UT-A1 as a novel drug target for hyponatremia. FASEB J 2024; 38:e23760. [PMID: 38924449 DOI: 10.1096/fj.202400555rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 06/06/2024] [Accepted: 06/13/2024] [Indexed: 06/28/2024]
Abstract
Hyponatremia is the most common disorder of electrolyte imbalances. It is necessary to develop new type of diuretics to treat hyponatremia without losing electrolytes. Urea transporters (UT) play an important role in the urine concentrating process and have been proved as a novel diuretic target. In this study, rat and mouse syndromes of inappropriate antidiuretic hormone secretion (SIADH) models were constructed and analyzed to determine if UTs are a promising drug target for treating hyponatremia. Experimental results showed that 100 mg/kg UT inhibitor 25a significantly increased serum osmolality (from 249.83 ± 5.95 to 294.33 ± 3.90 mOsm/kg) and serum sodium (from 114 ± 2.07 to 136.67 ± 3.82 mmol/L) respectively in hyponatremia rats by diuresis. Serum chemical examination showed that 25a neither caused another electrolyte imbalance nor influenced the lipid metabolism. Using UT-A1 and UT-B knockout mouse SIADH model, it was found that serum osmolality and serum sodium were lowered much less in UT-A1 knockout mice than in UT-B knockout mice, which suggest UT-A1 is a better therapeutic target than UT-B to treat hyponatremia. This study provides a proof of concept that UT-A1 is a diuretic target for SIADH-induced hyponatremia and UT-A1 inhibitors might be developed into new diuretics to treat hyponatremia.
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Affiliation(s)
- Nannan Li
- State Key Laboratory of Vascular Homeostasis and Remodeling, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Hang Zhang
- State Key Laboratory of Vascular Homeostasis and Remodeling, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Shuyuan Wang
- State Key Laboratory of Vascular Homeostasis and Remodeling, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Yue Xu
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, Ohio, USA
| | - Yi Ying
- State Key Laboratory of Vascular Homeostasis and Remodeling, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Jing Li
- The State Key Laboratory of Anti-Infective Drug Development, Sunshine Lake Pharma Co., Ltd., Dongguan, China
| | - Xiaowei Li
- State Key Laboratory of Vascular Homeostasis and Remodeling, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Min Li
- State Key Laboratory of Vascular Homeostasis and Remodeling, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Baoxue Yang
- State Key Laboratory of Vascular Homeostasis and Remodeling, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
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2
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Takata T, Hamada S, Mae Y, Iyama T, Ogihara R, Seno M, Nakamura K, Takata M, Sugihara T, Isomoto H. Uromodulin Regulates Murine Aquaporin-2 Activity via Thick Ascending Limb-Collecting Duct Cross-Talk during Water Deprivation. Int J Mol Sci 2022; 23:ijms23169410. [PMID: 36012675 PMCID: PMC9408883 DOI: 10.3390/ijms23169410] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 08/14/2022] [Accepted: 08/16/2022] [Indexed: 12/03/2022] Open
Abstract
Uromodulin, a urinary protein synthesized and secreted from the thick ascending limb (TAL) of the loop of Henle, is associated with hypertension through the activation of sodium reabsorption in the TAL. Uromodulin is a potential target for hypertension treatment via natriuresis. However, its biological function in epithelial cells of the distal nephron segment, particularly the collecting duct, remains unknown. Herein, we examined the regulation of uromodulin production during water deprivation in vivo as well as the effect of uromodulin on the activity of the water channel aquaporin−2 (AQP2) in vitro and in vivo using transgenic mice. Water deprivation upregulated uromodulin production; immunofluorescence experiments revealed uromodulin adhesion on the apical surface of the collecting duct. Furthermore, the activation of AQP2 was attenuated in mice lacking uromodulin. Uromodulin enhanced the phosphorylation and apical trafficking of AQP2 in mouse collecting duct cells treated with the vasopressin analog dDAVP. The uromodulin-induced apical trafficking of AQP2 was attenuated via endocytosis inhibitor treatment, suggesting that uromodulin activates AQP2 through the suppression of endocytosis. This study provides novel insights into the cross−talk between TAL and the collecting duct, and indicates that the modulation of uromodulin is a promising approach for diuresis and hypertension treatment.
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Affiliation(s)
- Tomoaki Takata
- Division of Gastroenterology and Nephrology, Faculty of Medicine, Tottori University, Yonago 683-8504, Japan
- Correspondence: ; Tel.: +81-859-38-6527
| | - Shintaro Hamada
- Division of Gastroenterology and Nephrology, Faculty of Medicine, Tottori University, Yonago 683-8504, Japan
| | - Yukari Mae
- Division of Gastroenterology and Nephrology, Faculty of Medicine, Tottori University, Yonago 683-8504, Japan
| | - Takuji Iyama
- Division of Gastroenterology and Nephrology, Faculty of Medicine, Tottori University, Yonago 683-8504, Japan
| | - Ryohei Ogihara
- Division of Gastroenterology and Nephrology, Faculty of Medicine, Tottori University, Yonago 683-8504, Japan
| | - Misako Seno
- Advanced Medicine & Translational Research Center, Organization for Research Initiative and Promotion, Tottori University, Yonago 683-8504, Japan
| | - Kazuomi Nakamura
- Advanced Medicine, Innovation and Clinical Research Center, Tottori University Hospital, Yonago 683-8504, Japan
| | - Miki Takata
- Division of Respiratory Medicine and Rheumatology, Faculty of Medicine, Tottori University, Yonago 683-8504, Japan
| | - Takaaki Sugihara
- Division of Gastroenterology and Nephrology, Faculty of Medicine, Tottori University, Yonago 683-8504, Japan
| | - Hajime Isomoto
- Division of Gastroenterology and Nephrology, Faculty of Medicine, Tottori University, Yonago 683-8504, Japan
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3
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Wang Z, Yu J, Hao D, Liu X, Wang X. Transcriptomic signatures responding to PKM2 activator TEPP-46 in the hyperglycemic human renal proximal epithelial tubular cells. Front Endocrinol (Lausanne) 2022; 13:965379. [PMID: 36120453 PMCID: PMC9471676 DOI: 10.3389/fendo.2022.965379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 08/01/2022] [Indexed: 11/22/2022] Open
Abstract
Pyruvate kinase M2 (PKM2), as the terminal and last rate-limiting enzyme of the glycolytic pathway, is an ideal enzyme for regulating metabolic phenotype. PKM2 tetramer activation has shown a protective role against diabetic kidney disease (DKD). However, the molecular mechanisms involved in diabetic tubular have not been investigated so far. In this study, we performed transcriptome gene expression profiling in human renal proximal tubular epithelial cell line (HK-2 cells) treated with 25 mM high D-glucose (HG) for 7 days before the addition of 10 μM TEPP-46, an activator of PKM2 tetramerization, for a further 1 day in the presence of HG. Afterwards, we analyzed the differentially expressed (DE) genes and investigated gene relationships based on weighted gene co-expression network analysis. The results showed that 2,902 DE genes were identified (adjusted P-value ≤ 0.05), where 2,509 DE genes (86.46%) were co-expressed in the key module. Four extremely downregulated DE genes (HSPA8, HSPA2, HSPA1B, and ARRB1) and three extremely upregulated DE genes (GADD45A, IGFBP3, and SIAH1) enriched in the downregulated endocytosis (hsa04144) and upregulated p53 signaling pathway (hsa04115), respectively, were validated by qRT-PCR experiments. The qRT-PCR results showed that the relative expression levels of HSPA8 [adjusted P-value = 4.45 × 10-34 and log2(FC) = -1.12], HSPA2 [adjusted P-value = 6.09 × 10-14 and log2(FC) = -1.27], HSPA1B [adjusted P-value = 1.14 × 10-11 and log2(FC) = -1.02], and ARRB1 [adjusted P-value = 2.60 × 10-5 and log2(FC) = -1.13] were significantly different (P-value < 0.05) from the case group to the control group. Furthermore, the interactions and predicted microRNAs of the key genes (HSPA8, HSPA2, HSPA1B, and ARRB1) were visualized in networks. This study identified the key candidate transcriptomic biomarkers and biological pathways in hyperglycemic HK-2 cells responding to the PKM2 activator TEPP-46 that can highlight a possibility of PKM2 tetramerization reshaping the interplay among endocytic trafficking through the versatile networks of Hsp70s and rewiring the crosstalk between EGFR signal transduction circuits and metabolic stress to promote resilience, which will be valuable for further research on PKM2 in DKD.
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Affiliation(s)
- Zhimin Wang
- Division of Endocrinology and Metabolic Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jiating Yu
- Division of Pediatric Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Dan Hao
- Shijiazhuang Zhongnongtongchuang (ZNTC) Biotechnology Co., Ltd., Shijiazhuang, China
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Xin Liu
- Division of Clinical Laboratory, Key Clinical Laboratory of Henan Province, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- *Correspondence: Xin Liu, ; Xiao Wang,
| | - Xiao Wang
- Konge Larsen ApS, Kongens Lyngby, Denmark
- College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, China
- *Correspondence: Xin Liu, ; Xiao Wang,
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4
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Greene ES, Cauble R, Kadhim H, de Almeida Mallmann B, Gu I, Lee SO, Orlowski S, Dridi S. Protective effects of the phytogenic feed additive "comfort" on growth performance via modulation of hypothalamic feeding- and drinking-related neuropeptides in cyclic heat-stressed broilers. Domest Anim Endocrinol 2021; 74:106487. [PMID: 32861191 DOI: 10.1016/j.domaniend.2020.106487] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 04/12/2020] [Accepted: 04/13/2020] [Indexed: 12/14/2022]
Abstract
Identification of alternatives to antibiotics in livestock and poultry is necessary. Fueled by consumer preferences, phytogenic feed additives are increasingly used in the food system; however, their mode of action is not well defined. Here, we used broiler chickens, in which appetite and feeding behavior regulation are controlled by complex mechanisms, to determine the effect of the phytogenic feed additive "comfort" (PFA-C) as well as its underlying molecular mechanisms on growth performance in heat-stressed broiler chickens. Heat stress significantly increased birds' core body temperature, water intake, and the hypothalamic expression of heat shock protein (HSP) 70, whereas it decreased feed intake, BW, and woody breast incidence. Phytogenic feed additive "comfort" supplementation downregulated the hypothalamic expression of HSP70, reduced core body temperature, increased feed and water intake, and improved BW in HS broilers. At molecular levels, the effect of PFA-C on growth performance seemed to be mediated by modulation of hypothalamic expression of melanocortin receptor 2, arginine vasopressin, aquaporin 2, and sodium and potassium-transporting ATPase subunit beta 1 polypeptides. In summary, PFA-C supplementation ameliorates heat stress productivity losses via a potential cytoprotective effect, reduction of hypothalamic intracellular stress, and modulation of hypothalamic feeding- and drinking-related polypeptide expression.
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Affiliation(s)
- E S Greene
- Department of Poultry Science, Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA
| | - R Cauble
- Department of Animal Science, University of Arkansas, Fayetteville, AR 72701, USA
| | - H Kadhim
- Department of Poultry Science, Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA
| | - B de Almeida Mallmann
- Department of Poultry Science, Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA
| | - I Gu
- Department of Food Science, University of Arkansas, Fayetteville, AR 72701, USA
| | - S-O Lee
- Department of Food Science, University of Arkansas, Fayetteville, AR 72701, USA
| | - S Orlowski
- Department of Poultry Science, Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA
| | - S Dridi
- Department of Poultry Science, Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA.
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5
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Fenton RA, Murali SK, Moeller HB. Advances in aquaporin-2 trafficking mechanisms and their implications for treatment of water balance disorders. Am J Physiol Cell Physiol 2020; 319:C1-C10. [PMID: 32432927 DOI: 10.1152/ajpcell.00150.2020] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In mammals, conservation of body water is critical for survival and is dependent on the kidneys' ability to minimize water loss in the urine during periods of water deprivation. The collecting duct water channel aquaporin-2 (AQP2) plays an essential role in this homeostatic response by facilitating water reabsorption along osmotic gradients. The ability to increase the levels of AQP2 in the apical plasma membrane following an increase in plasma osmolality is a rate-limiting step in water reabsorption, a process that is tightly regulated by the antidiuretic hormone arginine vasopressin (AVP). In this review, the focus is on the role of the carboxyl-terminus of AQP2 as a key regulatory point for AQP2 trafficking. We provide an overview of AQP2 structure, disease-causing mutations in the AQP2 carboxyl-terminus, the role of posttranslational modifications such as phosphorylation and ubiquitylation in the tail domain, and their implications for balanced trafficking of AQP2. Finally, we discuss how various modifications of the AQP2 tail facilitate selective protein-protein interactions that modulate the AQP2 trafficking mechanism.
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Affiliation(s)
- Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | - Hanne B Moeller
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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6
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Törnroth-Horsefield S. Phosphorylation of human AQP2 and its role in trafficking. VITAMINS AND HORMONES 2019; 112:95-117. [PMID: 32061351 DOI: 10.1016/bs.vh.2019.08.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Human Aquaporin 2 (AQP2) is a membrane-bound water channel found in the kidney collecting duct whose regulation by trafficking plays a key role in regulating urine volume. AQP2 trafficking is tightly controlled by the pituitary hormone arginine vasopressin (AVP), which stimulates translocation of AQP2 residing in storage vesicles to the apical membrane. The AVP-dependent translocation of AQP2 to and from the apical membrane is controlled by multiple phosphorylation sites in the AQP2 C-terminus, the phosphorylation of which alters its affinity to proteins within the cellular membrane protein trafficking machinery. The aim of this chapter is to provide a summary of what is currently known about AVP-mediated AQP2 trafficking, dissecting the roles of individual phosphorylation sites, kinases and phosphatases and interacting proteins. From this, the picture of an immensely complex process emerges, of which many structural and molecular details remains to be elucidated.
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7
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Tingskov SJ, Choi HJ, Holst MR, Hu S, Li C, Wang W, Frøkiær J, Nejsum LN, Kwon TH, Nørregaard R. Vasopressin-Independent Regulation of Aquaporin-2 by Tamoxifen in Kidney Collecting Ducts. Front Physiol 2019; 10:948. [PMID: 31447686 PMCID: PMC6695565 DOI: 10.3389/fphys.2019.00948] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 07/09/2019] [Indexed: 12/11/2022] Open
Abstract
Arginine vasopressin (AVP) mediates water reabsorption in the kidney collecting ducts through regulation of aquaporin-2 (AQP2). Also, estrogen has been known to regulate AQP2. Consistently, we previously demonstrated that tamoxifen (TAM), a selective estrogen receptor modulator, attenuates the downregulation of AQP2 in lithium-induced nephrogenic diabetes insipidus (NDI). In this study, we investigated the AVP-independent regulation of AQP2 by TAM and the therapeutic effect of TAM on the dysregulation of AQP2 and impaired urinary concentration in a unilateral ureteral obstruction (UUO) model. Primary cultured inner medullary collecting duct (IMCD) cells from kidneys of male Sprague-Dawley rats were treated with TAM. Rats subjected to 7 days of UUO were treated with TAM by oral gavage. Changes of intracellular trafficking and expression of AQP2 were evaluated by quantitative PCR, Western blotting, and immunohistochemistry. TAM induced AQP2 protein expression and intracellular trafficking in primary cultured IMCD cells, which were independent of the vasopressin V2 receptor (V2R) and cAMP activation, the critical pathways involved in AVP-stimulated regulation of AQP2. TAM attenuated the downregulation of AQP2 in TGF-β treated IMCD cells and IMCD suspensions prepared from UUO rats. TAM administration in vivo attenuated the downregulation of AQP2, associated with an improvement of urinary concentration in UUO rats. In addition, TAM increased CaMKII expression, suggesting that calmodulin signaling pathway is likely to be involved in the TAM-mediated AQP2 regulation. In conclusion, TAM is involved in AQP2 regulation in a vasopressin-independent manner and improves urinary concentration by attenuating the downregulation of AQP2 and maintaining intracellular trafficking in UUO.
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Affiliation(s)
| | - Hyo-Jung Choi
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Daegu, South Korea
| | - Mikkel R Holst
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Shan Hu
- Zhongshan School of Medicine, Institute of Hypertension, Sun Yat-sen University, Guangzhou, China
| | - Chunling Li
- Zhongshan School of Medicine, Institute of Hypertension, Sun Yat-sen University, Guangzhou, China
| | - Weidong Wang
- Zhongshan School of Medicine, Institute of Hypertension, Sun Yat-sen University, Guangzhou, China
| | - Jørgen Frøkiær
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Lene N Nejsum
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Tae-Hwan Kwon
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Daegu, South Korea
| | - Rikke Nørregaard
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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Jung HJ, Kwon TH. New insights into the transcriptional regulation of aquaporin-2 and the treatment of X-linked hereditary nephrogenic diabetes insipidus. Kidney Res Clin Pract 2019; 38:145-158. [PMID: 31189221 PMCID: PMC6577206 DOI: 10.23876/j.krcp.19.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 02/09/2019] [Accepted: 02/11/2019] [Indexed: 12/18/2022] Open
Abstract
The kidney collecting duct (CD) is a tubular segment of the kidney where the osmolality and final flow rate of urine are established, enabling urine concentration and body water homeostasis. Water reabsorption in the CD depends on the action of arginine vasopressin (AVP) and a transepithelial osmotic gradient between the luminal fluid and surrounding interstitium. AVP induces transcellular water reabsorption across CD principal cells through associated signaling pathways after binding to arginine vasopressin receptor 2 (AVPR2). This signaling cascade regulates the water channel protein aquaporin-2 (AQP2). AQP2 is exclusively localized in kidney connecting tubules and CDs. Specifically, AVP stimulates the intracellular translocation of AQP2-containing vesicles to the apical plasma membrane, increasing the osmotic water permeability of CD cells. Moreover, AVP induces transcription of the Aqp2 gene, increasing AQP2 protein abundance. This review provides new insights into the transcriptional regulation of the Aqp2 gene in the kidney CD with an overview of AVP and AQP2. It summarizes current therapeutic approaches for X-linked nephrogenic diabetes insipidus caused by AVPR2 gene mutations.
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Affiliation(s)
- Hyun Jun Jung
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Tae-Hwan Kwon
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Daegu, Korea
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Ranieri M, Di Mise A, Tamma G, Valenti G. Vasopressin-aquaporin-2 pathway: recent advances in understanding water balance disorders. F1000Res 2019; 8. [PMID: 30800291 PMCID: PMC6364380 DOI: 10.12688/f1000research.16654.1] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/23/2019] [Indexed: 12/11/2022] Open
Abstract
The alteration of water balance and related disorders has emerged as being strictly linked to the state of activation of the vasopressin–aquaporin-2
(vasopressin–AQP2) pathway. The lack of responsiveness of the kidney to the vasopressin action impairs its ability to concentrate the urine, resulting in polyuria, polydipsia, and risk of severe dehydration for patients. Conversely, non-osmotic release of vasopressin is associated with an increase in water permeability in the renal collecting duct, producing water retention and increasing the circulatory blood volume. This review highlights some of the new insights and recent advances in therapeutic intervention targeting the dysfunctions in the vasopressin–AQP2 pathway causing diseases characterized by water balance disorders such as congenital nephrogenic diabetes insipidus, syndrome of inappropriate antidiuretic hormone secretion, nephrogenic syndrome of inappropriate antidiuresis, and autosomal dominant polycystic kidney disease. The recent clinical data suggest that targeting the vasopressin–AQP2 axis can provide therapeutic benefits in patients with water balance disorders.
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Affiliation(s)
- Marianna Ranieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy, 70125, Italy
| | - Annarita Di Mise
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy, 70125, Italy
| | - Grazia Tamma
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy, 70125, Italy.,Istituto Nazionale di Biostrutture e Biosistemi, Rome, Roma, Italy, 00136, Italy
| | - Giovanna Valenti
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy, 70125, Italy.,Istituto Nazionale di Biostrutture e Biosistemi, Rome, Roma, Italy, 00136, Italy.,Center of Excellence in Comparative Genomics (CEGBA), University of Bari, Bari, Italy, 70125, Italy
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10
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The Expanding Role of Vesicles Containing Aquaporins. Cells 2018; 7:cells7100179. [PMID: 30360436 PMCID: PMC6210599 DOI: 10.3390/cells7100179] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 10/16/2018] [Accepted: 10/20/2018] [Indexed: 12/11/2022] Open
Abstract
In animals and plants, membrane vesicles containing proteins have been defined as key for biological systems involving different processes such as trafficking or intercellular communication. Docking and fusion of vesicles to the plasma membrane occur in living cells in response to different stimuli, such as environmental changes or hormones, and therefore play an important role in cell homeostasis as vehicles for certain proteins or other substances. Because aquaporins enhance the water permeability of membranes, their role as proteins immersed in vesicles formed of natural membranes is a recent topic of study. They regulate numerous physiological processes and could hence serve new biotechnological purposes. Thus, in this review, we have explored the physiological implications of the trafficking of aquaporins, the mechanisms that control their transit, and the proteins that coregulate the migration. In addition, the importance of exosomes containing aquaporins in the cell-to-cell communication processes in animals and plants have been analyzed, together with their potential uses in biomedicine or biotechnology. The properties of aquaporins make them suitable for use as biomarkers of different aquaporin-related diseases when they are included in exosomes. Finally, the fact that these proteins could be immersed in biomimetic membranes opens future perspectives for new biotechnological applications.
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Roche JV, Törnroth-Horsefield S. Aquaporin Protein-Protein Interactions. Int J Mol Sci 2017; 18:ijms18112255. [PMID: 29077056 PMCID: PMC5713225 DOI: 10.3390/ijms18112255] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 10/20/2017] [Accepted: 10/23/2017] [Indexed: 12/20/2022] Open
Abstract
Aquaporins are tetrameric membrane-bound channels that facilitate transport of water and other small solutes across cell membranes. In eukaryotes, they are frequently regulated by gating or trafficking, allowing for the cell to control membrane permeability in a specific manner. Protein–protein interactions play crucial roles in both regulatory processes and also mediate alternative functions such as cell adhesion. In this review, we summarize recent knowledge about aquaporin protein–protein interactions; dividing the interactions into three types: (1) interactions between aquaporin tetramers; (2) interactions between aquaporin monomers within a tetramer (hetero-tetramerization); and (3) transient interactions with regulatory proteins. We particularly focus on the structural aspects of the interactions, discussing the small differences within a conserved overall fold that allow for aquaporins to be differentially regulated in an organism-, tissue- and trigger-specific manner. A deep knowledge about these differences is needed to fully understand aquaporin function and regulation in many physiological processes, and may enable design of compounds targeting specific aquaporins for treatment of human disease.
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Affiliation(s)
- Jennifer Virginia Roche
- Department of Biochemistry and Structural Biology, Center for Molecular Protein Science, Lund University, Box 124, 221 00 Lund, Sweden.
| | - Susanna Törnroth-Horsefield
- Department of Biochemistry and Structural Biology, Center for Molecular Protein Science, Lund University, Box 124, 221 00 Lund, Sweden.
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12
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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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13
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Roche JV, Survery S, Kreida S, Nesverova V, Ampah-Korsah H, Gourdon M, Deen PMT, Törnroth-Horsefield S. Phosphorylation of human aquaporin 2 (AQP2) allosterically controls its interaction with the lysosomal trafficking protein LIP5. J Biol Chem 2017; 292:14636-14648. [PMID: 28710278 DOI: 10.1074/jbc.m117.788364] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Revised: 07/07/2017] [Indexed: 12/21/2022] Open
Abstract
The interaction between the renal water channel aquaporin-2 (AQP2) and the lysosomal trafficking regulator-interacting protein LIP5 targets AQP2 to multivesicular bodies and facilitates lysosomal degradation. This interaction is part of a process that controls AQP2 apical membrane abundance in a vasopressin-dependent manner, allowing for urine volume adjustment. Vasopressin regulates phosphorylation at four sites within the AQP2 C terminus (Ser256, Ser261, Ser264, and Thr269), of which Ser256 is crucial and sufficient for AQP2 translocation from storage vesicles to the apical membrane. However, whether AQP2 phosphorylation modulates AQP2-LIP5 complex affinity is unknown. Here we used far-Western blot analysis and microscale thermophoresis to show that the AQP2 binds LIP5 in a phosphorylation-dependent manner. We constructed five phospho-mimicking mutants (S256E, S261E, S264E, T269E, and S256E/T269E) and a C-terminal truncation mutant (ΔP242) that lacked all phosphorylation sites but retained a previously suggested LIP5-binding site. CD spectroscopy indicated that wild-type AQP2 and the phospho-mimicking mutants had similar overall structure but displayed differences in melting temperatures possibly arising from C-terminal conformational changes. Non-phosphorylated AQP2 bound LIP5 with the highest affinity, whereas AQP2-ΔP242 had 20-fold lower affinity as determined by microscale thermophoresis. AQP2-S256E, S261E, T269E, and S256E/T269E all had reduced affinity. This effect was most prominent for AQP2-S256E, which fits well with its role in apical membrane targeting. AQP2-S264E had affinity similar to non-phosphorylated AQP2, possibly indicating a role in exosome excretion. Our data suggest that AQP2 phosphorylation allosterically controls its interaction with LIP5, illustrating how altered affinities to interacting proteins form the basis for regulation of AQP2 trafficking by post-translational modifications.
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Affiliation(s)
- Jennifer Virginia Roche
- From the Department of Biochemistry and Structural Biology, Lund University, 221 00 Lund, Sweden and
| | - Sabeen Survery
- From the Department of Biochemistry and Structural Biology, Lund University, 221 00 Lund, Sweden and
| | - Stefan Kreida
- From the Department of Biochemistry and Structural Biology, Lund University, 221 00 Lund, Sweden and
| | - Veronika Nesverova
- From the Department of Biochemistry and Structural Biology, Lund University, 221 00 Lund, Sweden and
| | - Henry Ampah-Korsah
- From the Department of Biochemistry and Structural Biology, Lund University, 221 00 Lund, Sweden and
| | - Maria Gourdon
- From the Department of Biochemistry and Structural Biology, Lund University, 221 00 Lund, Sweden and
| | - Peter M T Deen
- the Department of Physiology, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
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14
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Lee MS, Choi HJ, Park EJ, Park HJ, Kwon TH. Depletion of vacuolar protein sorting-associated protein 35 is associated with increased lysosomal degradation of aquaporin-2. Am J Physiol Renal Physiol 2016; 311:F1294-F1307. [PMID: 27733367 DOI: 10.1152/ajprenal.00307.2016] [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: 05/20/2016] [Revised: 09/22/2016] [Accepted: 10/07/2016] [Indexed: 11/22/2022] Open
Abstract
The carboxyl terminus of aquaporin-2 (AQP2c) undergoes posttranslational modifications, including phosphorylation and ubiquitination, in the process of regulating aquaporin-2 (AQP2) translocation and protein abundance. We aimed to identify novel proteins interacting with AQP2c. Recombinant AQP2c protein was made in Escherichia coli BL21 (DE3) cells by exploiting the pET32 TrxA fusion system. Lysates of rat kidney inner medullary collecting duct (IMCD) tubule suspensions interacted with rat AQP2c bound to Ni2+-resin were subjected to LC-MS/MS proteomic analysis. Potential interacting proteins were identified, including vacuolar protein sorting-associated protein 35 (Vps35). Coimmunoprecipitation assay demonstrated that Vps35 interacted with AQP2c. Immunohistochemistry of rat kidney revealed that AQP2 and Vps35 were partly colocalized at the intracellular vesicles in collecting duct cells. The role of Vps35 in AQP2 regulation induced by 1-deamino-8D-arginine vasopressin (dDAVP) was examined in mpkCCDc14 cells. Cell surface biotinylation assay demonstrated that dDAVP-induced apical translocation of AQP2 was significantly decreased under siRNA-mediated Vps35 knockdown. dDAVP-induced AQP2 upregulation was less prominent in the cells with Vps35 knockdown. Moreover, AQP2 protein abundance was decreased to a greater extent during the withdrawal period after dDAVP stimulation under Vps35 knockdown, which was significantly inhibited by chloroquine (a blocker of the lysosomal pathway) but not by MG132 (a proteasome inhibitor). Immunocytochemistry demonstrated that internalized AQP2 was more associated with lysosomal-associated membrane protein 1 (LAMP-1) in primary cultured IMCD cells under a Vps35 knockdown situation. Taken together, our results show that Vps35 interacts with AQP2c, and depletion of Vps35 is likely to be associated with decreased AQP2 trafficking and increased lysosomal degradation of AQP2 protein.
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Affiliation(s)
- Mi Suk Lee
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea; and.,BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science, Kyungpook National University, Taegu, Korea
| | - Hyo-Jung Choi
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea; and
| | - Eui-Jung Park
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea; and.,BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science, Kyungpook National University, Taegu, Korea
| | - Hye-Jeong Park
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea; and.,BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science, Kyungpook National University, Taegu, Korea
| | - Tae-Hwan Kwon
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea; and .,BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science, Kyungpook National University, Taegu, Korea
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15
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Kristensen MLV, Kierulf-Lassen C, Nielsen PM, Krag S, Birn H, Nejsum LN, Nørregaard R. Remote ischemic perconditioning attenuates ischemia/reperfusion-induced downregulation of AQP2 in rat kidney. Physiol Rep 2016; 4:4/13/e12865. [PMID: 27405971 PMCID: PMC4945844 DOI: 10.14814/phy2.12865] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Accepted: 06/21/2016] [Indexed: 12/28/2022] Open
Abstract
Renal ischemia/reperfusion (I/R) can lead to impaired urine concentration ability and increased fractional excretion of sodium (FeNa). Local ischemic preconditioning improves renal water and sodium handling after I/R injury. Here, we investigate whether remote ischemic perconditioning (rIPeC) prevents dysregulation of renal water and salt handling in response to I/R injury and mechanisms that may be involved. Rats were subjected to right nephrectomy and randomized into a sham group or an I/R group. In the I/R group, rats were subjected to 37 min of renal ischemia and 3 days of reperfusion. rIPeC was applied to the abdominal aorta. Blood and urine were collected on day 3 postoperatively for clearance studies. The expression of aquaporins (AQPs) and the sodium transporter Na-K-ATPase were analyzed using immunoblotting and immunohistochemistry. I/R injury resulted in polyuria, increased FeNa, and decreased urine osmolality compared to sham rats. rIPeC attenuated the increase in FeNa and the decrease in urine osmolality. Expression of AQP1, AQP2, phosphorylated AQP2 (pAQP2), and Na-K-ATPase was downregulated in I/R rats. rIPeC attenuated the reductions in AQP2 and pAQP2 expression. Immunohistochemistry revealed decreased labeling of Na-K-ATPase in the outer medulla in I/R kidneys compared to kidneys from sham and I/R + rIPeC rats. After renal ischemia, the expression of Na-K-ATPase was substantially reduced in the outer medullary thick ascending limb. In conclusion, our data suggest that rIPeC might prevent dysregulation of renal water and salt handling via regulation of AQP2 expression and phosphorylation as well as via regulation of Na-K-ATPase expression in I/R rat kidneys.
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Affiliation(s)
| | | | - Per Mose Nielsen
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Søren Krag
- Department of Pathology, Aarhus University, Aarhus, Denmark
| | - Henrik Birn
- Department of Biomedicine, Aarhus University, Aarhus, Denmark Department of Renal Medicine, Aarhus University, Aarhus, Denmark
| | - Lene N Nejsum
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Rikke Nørregaard
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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16
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Vukićević T, Schulz M, Faust D, Klussmann E. The Trafficking of the Water Channel Aquaporin-2 in Renal Principal Cells-a Potential Target for Pharmacological Intervention in Cardiovascular Diseases. Front Pharmacol 2016; 7:23. [PMID: 26903868 PMCID: PMC4749865 DOI: 10.3389/fphar.2016.00023] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 01/25/2016] [Indexed: 01/13/2023] Open
Abstract
Arginine-vasopressin (AVP) stimulates the redistribution of water channels, aquaporin-2 (AQP2) from intracellular vesicles into the plasma membrane of renal collecting duct principal cells. By this AVP directs 10% of the water reabsorption from the 170 L of primary urine that the human kidneys produce each day. This review discusses molecular mechanisms underlying the AVP-induced redistribution of AQP2; in particular, it provides an overview over the proteins participating in the control of its localization. Defects preventing the insertion of AQP2 into the plasma membrane cause diabetes insipidus. The disease can be acquired or inherited, and is characterized by polyuria and polydipsia. Vice versa, up-regulation of the system causing a predominant localization of AQP2 in the plasma membrane leads to excessive water retention and hyponatremia as in the syndrome of inappropriate antidiuretic hormone secretion (SIADH), late stage heart failure or liver cirrhosis. This article briefly summarizes the currently available pharmacotherapies for the treatment of such water balance disorders, and discusses the value of newly identified mechanisms controlling AQP2 for developing novel pharmacological strategies. Innovative concepts for the therapy of water balance disorders are required as there is a medical need due to the lack of causal treatments.
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Affiliation(s)
- Tanja Vukićević
- Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association Berlin, Germany
| | - Maike Schulz
- Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association Berlin, Germany
| | - Dörte Faust
- Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association Berlin, Germany
| | - Enno Klussmann
- Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz AssociationBerlin, Germany; German Centre for Cardiovascular ResearchBerlin, Germany
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17
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Kim JE, Jung HJ, Lee YJ, Kwon TH. Vasopressin-regulated miRNAs and AQP2-targeting miRNAs in kidney collecting duct cells. Am J Physiol Renal Physiol 2015; 308:F749-64. [DOI: 10.1152/ajprenal.00334.2014] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 01/21/2015] [Indexed: 12/29/2022] Open
Abstract
Mature microRNA (miRNA) acts as an important posttranscriptional regulator. We aimed to profile vasopressin-responsive miRNAs in kidney inner medullary collecting duct cells and to identify aquaporin-2 (AQP2)-targeting miRNAs. Microarray chip assay was carried out in inner medullary collecting duct tubule suspensions from rat kidneys in the absence or presence of desmopressin (dDAVP) stimulation (10−9 M, 2 h). The results demonstrated 19 miRNAs, including both precursor and mature miRNAs, as potential candidates that showed significant changes in expression after dDAVP stimulation ( P < 0.05). Nine mature miRNAs exhibiting >1.3-fold changes in expression on the microarray (miR-127, miR-1, miR-873, miR-16, miR-206, miR-678, miR-496, miR-298, and miR-463) were further examined by quantitative real-time PCR, and target genes of the selected miRNAs were predicted. Next, to identify AQP2-targeting miRNAs, in silico analysis was performed. Four miRNAs (miR-32, miR-137, miR-216a, and miR-216b) target the 3′-untranslated region of rat AQP2 mRNA. Target seed regions of miR-32 and miR-137 were also conserved in the 3′-untranslated region of mouse AQP2 mRNA. Quantitative real-time PCR and immunoblot analysis demonstrated that dDAVP-induced AQP2 expression was significantly attenuated in mpkCCDc14 cells when cells were transfected with miRNA mimics of miR-32 or miR-137. Moreover, luciferase reporter assay demonstrated a significant decrease of AQP2 translation in mpkCCDc14 cells transfected with miRNA mimics of miR-32 or miR-137. The present study provides novel insights into the regulation of AQP2 by RNA interference; however, vasopressin-regulated miRNAs did not include miR-32 or miR-137, indicating that the interaction of miRNAs with the AQP2 regulatory pathway requires further analysis.
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Affiliation(s)
- Jae-Eun Kim
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea
- BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science, Kyungpook National University, Taegu, Korea
| | - Hyun Jun Jung
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea
| | - Yu-Jung Lee
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea
- BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science, Kyungpook National University, Taegu, Korea
| | - Tae-Hwan Kwon
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea
- BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science, Kyungpook National University, Taegu, Korea
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18
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Choi HJ, Jung HJ, Kwon TH. Extracellular pH affects phosphorylation and intracellular trafficking of AQP2 in inner medullary collecting duct cells. Am J Physiol Renal Physiol 2015; 308:F737-48. [DOI: 10.1152/ajprenal.00376.2014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 01/21/2015] [Indexed: 12/29/2022] Open
Abstract
Kidney collecting duct cells are continuously exposed to the changes of extracellular pH (pHe). We aimed to study the effects of altered pHe on desmopressin (dDAVP)-induced phosphorylation (Ser256, Ser261, Ser264, and Ser269) and apical targeting of aquaporin-2 (AQP2) in rat kidney inner medullary collecting duct (IMCD) cells. When freshly prepared IMCD tubule suspensions exposed to HEPES buffer with pH 5.4, 6.4, 7.4, or 8.4 for 1 h were stimulated with dDAVP (10−10 M, 3 min), AQP2 phosphorylation at Ser256, Ser264, and Ser269 was significantly attenuated under acidic conditions. Next, IMCD cells primary cultured in transwell chambers were exposed to a transepithelial pH gradient for 1 h (apical pH 6.4, 7.4, or 8.4 vs. basolateral pH 7.4 and vice versa). Immunocytochemistry and cell surface biotinylation assay revealed that exposure to either apical pH 6.4 or basolateral pH 6.4 for 1 h was associated with decreased dDAVP (10−9 M, 15 min, basolateral)-induced apical targeting of AQP2 and surface expression of AQP2. Fluorescence resonance energy transfer analysis revealed that the dDAVP (10−9 M)-induced increase of PKA activity was significantly attenuated when LLC-PK1 cells were exposed to pHe 6.4 compared with pHe 7.4 and 8.4. In contrast, forskolin (10−7 M)-induced PKA activation and dDAVP (10−9 M)-induced increases of intracellular Ca2+ were not affected. Taken together, dDAVP-induced phosphorylation and apical targeting of AQP2 are attenuated in IMCD cells under acidic pHe, likely via an inhibition of vasopressin V2 receptor-G protein-cAMP-PKA actions.
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Affiliation(s)
- Hyo-Jung Choi
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea; and
- BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science, Kyungpook National University, Taegu, Korea
| | - Hyun Jun Jung
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea; and
| | - Tae-Hwan Kwon
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea; and
- BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science, Kyungpook National University, Taegu, Korea
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19
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Jung HJ, Kim SY, Choi HJ, Park EJ, Lim JS, Frøkiaer J, Nielsen S, Kwon TH. Tankyrase-mediated β-catenin activity regulates vasopressin-induced AQP2 expression in kidney collecting duct mpkCCDc14 cells. Am J Physiol Renal Physiol 2014; 308:F473-86. [PMID: 25520007 DOI: 10.1152/ajprenal.00052.2014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Aquaporin-2 (AQP2) mediates arginine vasopressin (AVP)-induced water reabsorption in the kidney collecting duct. AVP regulates AQP2 expression primarily via Gsα/cAMP/PKA signaling. Tankyrase, a member of the poly(ADP-ribose) polymerase family, is known to mediate Wnt/β-catenin signaling-induced gene expression. We examined whether tankyrase plays a role in AVP-induced AQP2 regulation via ADP-ribosylation of G protein-α (Gα) and/or β-catenin-mediated transcription of AQP2. RT-PCR and immunoblotting analysis revealed the mRNA and protein expression of tankyrase in mouse kidney and mouse collecting duct mpkCCDc14 cells. dDAVP-induced AQP2 upregulation was attenuated in mpkCCDc14 cells under the tankyrase inhibition by XAV939 treatment or small interfering (si) RNA knockdown. Fluorescence resonance energy transfer image analysis, however, revealed that XAV939 treatment did not affect dDAVP- or forskolin-induced PKA activation. Inhibition of tankyrase decreased dDAVP-induced phosphorylation of β-catenin (S552) and nuclear translocation of phospho-β-catenin. siRNA-mediated knockdown of β-catenin decreased forskolin-induced AQP2 transcription and dDAVP-induced AQP2 expression. Moreover, inhibition of phosphoinositide 3-kinase/Akt, which was associated with decreased nuclear translocation of β-catenin, diminished dDAVP-induced AQP2 upregulation, further indicating that β-catenin mediates AQP2 expression. Taken together, tankyrase plays a role in AVP-induced AQP2 regulation, which is likely via β-catenin-mediated transcription of AQP2, but not ADP-ribosylation of Gα. The results provide novel insights into vasopressin-mediated urine concentration and homeostasis of body water metabolism.
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Affiliation(s)
- Hyun Jun Jung
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, South Korea
| | - Sang-Yeob Kim
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, South Korea
| | - Hyo-Jung Choi
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, South Korea
| | - Eui-Jung Park
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, South Korea
| | - Jung-Suk Lim
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, South Korea
| | - Jørgen Frøkiaer
- The Water and Salt Research Center, Department of Biomedicine, Aarhus University, Aarhus C, Denmark; and
| | - Søren Nielsen
- The Water and Salt Research Center, Department of Biomedicine, Aarhus University, Aarhus C, Denmark; and Institute of Medicine and Health Technology, Aalborg University, Aalborg, Denmark
| | - Tae-Hwan Kwon
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, South Korea;
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20
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Regulation of aquaporin-2 in the kidney: A molecular mechanism of body-water homeostasis. Kidney Res Clin Pract 2013; 32:96-102. [PMID: 26877923 PMCID: PMC4714093 DOI: 10.1016/j.krcp.2013.07.005] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 06/29/2013] [Indexed: 11/22/2022] Open
Abstract
The kidneys play a key role in the homeostasis of body water and electrolyte balance. Aquaporin-2 (AQP2) is the vasopressin-regulated water-channel protein expressed at the connecting tubule and collecting duct, and plays a key role in urine concentration and body-water homeostasis through short-term and long-term regulation of collecting duct water permeability. The signaling transduction pathways resulting in the AQP2 trafficking to the apical plasma membrane of the collecting duct principal cells, including AQP2 phosphorylation, RhoA phosphorylation, actin depolymerization, and calcium mobilization, and the changes of AQP2 abundance in water-balance disorders have been extensively studied. Dysregulation of AQP2 has been shown to be importantly associated with a number of clinical conditions characterized by body-water balance disturbances, including hereditary nephrogenic diabetes insipidus (NDI), lithium-induced NDI, electrolytes disturbance, acute and chronic renal failure, ureteral obstruction, nephrotic syndrome, congestive heart failure, and hepatic cirrhosis. Recent studies exploiting omics technology further demonstrated the comprehensive vasopressin signaling pathways in the collecting ducts. Taken together, these studies elucidate the underlying molecular mechanisms of body-water homeostasis and provide the basis for the treatment of body-water balance disorders.
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