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Guo X, Kong Y, Kwon TH, Li C, Wang W. Autophagy and regulation of aquaporins in the kidneys. Kidney Res Clin Pract 2023; 42:676-685. [PMID: 37098672 DOI: 10.23876/j.krcp.22.247] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Accepted: 12/20/2022] [Indexed: 04/27/2023] Open
Abstract
Aquaporins (AQPs) are water channel proteins that facilitate the transport of water molecules across cell membranes. To date, seven AQPs have been found to be expressed in mammal kidneys. The cellular localization and regulation of the transport properties of AQPs in the kidney have been widely investigated. Autophagy is known as a highly conserved lysosomal pathway, which degrades cytoplasmic components. Through basal autophagy, kidney cells maintain their functions and structure. As a part of the adaptive responses of the kidney, autophagy may be altered in response to stress conditions. Recent studies revealed that autophagic degradation of AQP2 in the kidney collecting ducts leads to impaired urine concentration in animal models with polyuria. Therefore, the modulation of autophagy could be a therapeutic approach to treat water balance disorders. However, as autophagy is either protective or deleterious, it is crucial to establish an optimal condition and therapeutic window where autophagy induction or inhibition could yield beneficial effects. Further studies are needed to understand both the regulation of autophagy and the interaction between AQPs and autophagy in the kidneys in renal diseases, including nephrogenic diabetes insipidus.
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Affiliation(s)
- Xiangdong Guo
- Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
- Department of Physiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Yonglun Kong
- Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Tae-Hwan Kwon
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Chunling Li
- Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
- Department of Physiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Weidong Wang
- Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
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Xu C, Yi X, Tang L, Wang H, Chu S, Yu J. Differential regulation of autophagy on urine-concentrating capability through modulating the renal AQP2 expression and renin-angiotensin system in mice. Am J Physiol Renal Physiol 2023; 325:F503-F518. [PMID: 37589054 DOI: 10.1152/ajprenal.00018.2023] [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: 01/30/2023] [Revised: 08/02/2023] [Accepted: 08/07/2023] [Indexed: 08/18/2023] Open
Abstract
Autophagy, a cellular process of "self-eating," plays an essential role in renal pathophysiology. However, the effect of autophagy on urine-concentrating ability in physiological conditions is still unknown. This study aimed to determine the relevance and mechanisms of autophagy for maintaining urine-concentrating capability during antidiuresis. The extent of the autophagic response to water deprivation (WD) was different between the renal cortex and medulla in mice. Autophagy activity levels in the renal cortex were initially suppressed and then stimulated by WD in a time-dependent manner. During 48 h WD, the urine-concentrating capability of mice was impaired by rapamycin (Rapa) but not by 3-methyladenine (3-MA), accompanied by suppressed renal aquaporin 2 (AQP2), V2 receptor (V2R), renin, and angiotensin-converting enzyme (ACE) expression, and levels of prorenin/renin, angiotensin II (ANG II), and aldosterone in the plasma and urine. In contrast, 3-MA and chloroquine (CQ) suppressed the urine-concentrating capability in WD72 mice, accompanied by downregulation of AQP2 and V2R expression in the renal cortex. 3-MA and CQ further increased AQP2 and V2R expression in the renal medulla of WD72 mice. Compared with 3-MA and CQ, Rapa administration yielded completely opposite results on the above parameters in WD72 mice. In addition, 3-MA and CQ abolished the upregulation of prorenin/renin, ANG II, and aldosterone levels in the plasma and urine in WD72 mice. Taken together, our study demonstrated that autophagy regulated urine-concentrating capability through differential regulation of renal AQP2/V2R and ACE/ANG II signaling during WD.NEW & NOTEWORTHY Autophagy exhibits a double-edged effect on cell survival and plays an essential role in renal pathophysiology. We for the first time reported a novel function of autophagy that controls the urine-concentrating capability in physiological conditions. We found that water deprivation (WD) differentially regulated autophagy in the kidneys of mice in a time-dependent manner and autophagy regulates the urine-concentrating capability mainly by regulating AQP2/V2R and ACE/ANG II signaling in the renal cortex in WD mice.
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Affiliation(s)
- Chuanming Xu
- Translational Medicine Centre, Jiangxi University of Chinese Medicine, Nanchang, People's Republic of China
| | - Xiaoli Yi
- Translational Medicine Centre, Jiangxi University of Chinese Medicine, Nanchang, People's Republic of China
| | - Le Tang
- Translational Medicine Centre, Jiangxi University of Chinese Medicine, Nanchang, People's Republic of China
| | - Hui Wang
- Translational Medicine Centre, Jiangxi University of Chinese Medicine, Nanchang, People's Republic of China
| | - Shuhan Chu
- Translational Medicine Centre, Jiangxi University of Chinese Medicine, Nanchang, People's Republic of China
| | - Jun Yu
- Center for Metabolic Disease Research and Department of Cardiovascular Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, United States
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AQP2 trafficking in health and diseases: an updated overview. Int J Biochem Cell Biol 2022; 149:106261. [DOI: 10.1016/j.biocel.2022.106261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 05/25/2022] [Accepted: 06/30/2022] [Indexed: 11/23/2022]
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Yang HH, Su SH, Ho CH, Yeh AH, Lin YJ, Yu MJ. Glucocorticoid Receptor Maintains Vasopressin Responses in Kidney Collecting Duct Cells. Front Physiol 2022; 13:816959. [PMID: 35685285 PMCID: PMC9173664 DOI: 10.3389/fphys.2022.816959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 03/28/2022] [Indexed: 11/22/2022] Open
Abstract
Water permeability of the kidney collecting ducts is regulated in part by the amount of the molecular water channel protein aquaporin-2 (AQP2), whose expression, in turn, is regulated by the pituitary peptide hormone vasopressin. We previously showed that stable glucocorticoid receptor knockdown diminished the vasopressin-induced Aqp2 gene expression in the collecting duct cell model mpkCCD. Here, we investigated the pathways regulated by the glucocorticoid receptor by comparing transcriptomes of the mpkCCD cells with or without stable glucocorticoid receptor knockdown. Glucocorticoid receptor knockdown downregulated 5,394 transcripts associated with 55 KEGG pathways including "vasopressin-regulated water reabsorption," indicative of positive regulatory roles of these pathways in the vasopressin-induced Aqp2 gene expression. Quantitative RT-PCR confirmed the downregulation of the vasopressin V2 receptor transcript upon glucocorticoid receptor knockdown. Glucocorticoid receptor knockdown upregulated 3,785 transcripts associated with 42 KEGG pathways including the "TNF signaling pathway" and "TGFβ signaling pathway," suggesting the negative regulatory roles of these pathways in the vasopressin-induced Aqp2 gene expression. Quantitative RT-PCR confirmed the upregulation of TNF and TGFβ receptor transcripts upon glucocorticoid receptor knockdown. TNF or TGFβ inhibitor alone, in the absence of vasopressin, did not induce Aqp2 gene transcription. However, TNF or TGFβ blunted the vasopressin-induced Aqp2 gene expression. In particular, TGFβ reduced vasopressin-induced increases in Akt phosphorylation without inducing epithelial-to-mesenchymal transition or interfering with vasopressin-induced apical AQP2 trafficking. In summary, our RNA-seq transcriptomic comparison revealed positive and negative regulatory pathways maintained by the glucocorticoid receptor for the vasopressin-induced Aqp2 gene expression.
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Affiliation(s)
| | | | | | | | | | - Ming-Jiun Yu
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
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Campagno RV, Nosetto EC, Brandoni A, Torres AM. Hepatic and renal expression of Oatp1 in obstructive uropathy. First detection of Oatp1 in urine, a potential biomarker. Clin Exp Pharmacol Physiol 2021; 48:987-995. [PMID: 33738813 DOI: 10.1111/1440-1681.13499] [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: 12/19/2020] [Revised: 03/12/2021] [Accepted: 03/15/2021] [Indexed: 11/29/2022]
Abstract
Obstructive renal diseases affect renal function and kidney integrity. Nevertheless, little is known about its systemic or extra-renal effects. The organic anion transporting polypeptide 1 (Oatp1) is a carrier expressed in liver and kidneys. In this study, the hepatic and renal expression of Oatp1 was evaluated in rats with obstructive nephropathy. Moreover, the urinary excretion of Oatp1 (Oatp1u ) was evaluated as a potential biomarker for this pathology. Male Wistar rats with bilateral ureteral obstruction for 5 hours (BUO5), 24 hours (BUO24) or sham operated were used. After 24 hours of ureteral releasing, liver and kidney functional parameters, histopathology, Oatp1 tissular expression and Oatp1u were evaluated. For Oatp1u evaluation two groups were added; BUO1 and BUO2 (1 and 2 hours of ureteral obstruction, respectively). Both liver and kidney functional parameters and histopathological studies showed alterations in BUO5 and BUO24. In hepatic homogenates, Oatp1 significantly decreased in BUO groups and in total liver membranes no modifications were observed. In renal homogenates, Oatp1 significantly decreased in BUO groups, but in apical kidney membranes, its expression was increased. Oatp1u was only detected in BUO groups, even in those (BUO1, BUO2) in which no alterations in the traditional parameters of renal function were observed. Modulations in liver and renal expression of Oatp1 could be an organism strategy to attenuate the effects of the disease and an attempt to maintain the complex organ cross-talk between liver and kidneys. Oatp1u could be a new, early and specific biomarker of obstructive nephropathy.
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Affiliation(s)
- Romina V Campagno
- Área Farmacología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, CONICET, Rosario, Argentina
| | - Evangelina C Nosetto
- Área Farmacología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, CONICET, Rosario, Argentina
| | - Anabel Brandoni
- Área Farmacología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, CONICET, Rosario, Argentina
| | - Adriana M Torres
- Área Farmacología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, CONICET, Rosario, Argentina
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Brandoni A, Torres AM. Renal expression and urinary excretion of aquaporin-2 in postobstructive uropathy in rats. Can J Physiol Pharmacol 2021; 99:619-626. [PMID: 34048270 DOI: 10.1139/cjpp-2020-0481] [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] [Indexed: 11/22/2022]
Abstract
This work assessed the time course of water renal management together with aquaporin-2 (AQP2) kidney expression and urinary AQP2 levels (AQP2u) in obstructive nephropathy. Adult male Wistar rats were monitored after 1, 2, and 7 days of bilateral ureteral release (bilateral ureteral obstruction (BUO); BUO-1, BUO-2 and BUO-7). Renal water handling was evaluated using conventional clearance techniques. AQP2 levels were assessed by immunoblotting and immunohistochemical techniques. AQP2 expression in apical membranes was downregulated in BUO-1 rats and upregulated both in BUO-2 and BUO-7 animals. AQP2 protein expression in whole cell lysate fraction from kidney cortex and medulla were significantly decreased in all the experimental groups. Concomitantly, mRNA levels of AQP2 decreased in renal medulla of all groups and in renal cortex from BUO-1; however, in renal cortex from BUO-2 and BUO-7 a recovery and an increase in the level of AQP2 mRNA were, respectively, observed. BUO-7 group showed a significant increase in AQP2u. The alterations observed in apical membranes AQP2 expression could explain, at least in part, the evolution time of water kidney management in the postobstructive phase of BUO. Additionally, the AQP2u increase after 7 days of ureteral release may be postulated as a biomarker of improvement in the kidney function.
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Affiliation(s)
- Anabel Brandoni
- Área Farmacología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, CONICET, Rosario, Santa Fe 2000, Argentina
- Área Farmacología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, CONICET, Rosario, Santa Fe 2000, Argentina
| | - Adriana M Torres
- Área Farmacología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, CONICET, Rosario, Santa Fe 2000, Argentina
- Área Farmacología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, CONICET, Rosario, Santa Fe 2000, Argentina
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Campagno RV, Nosetto EC, Brandoni A, Torres AM. Utility of urinary organic anion transporter 5 as an early biomarker of obstructive nephropathy. Clin Exp Pharmacol Physiol 2020; 47:1674-1681. [PMID: 32497308 DOI: 10.1111/1440-1681.13360] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 05/19/2020] [Accepted: 05/26/2020] [Indexed: 12/11/2022]
Abstract
Ureteral obstruction is a relevant cause of kidney damage. The traditional parameters used in clinical practice for the detection of renal injury are insensitive and non-specific for the diagnosis of obstructive renal disease. The organic anion transporter 5 (Oat5) is a carrier expressed exclusively in the kidney. In this study, the Oat5 urinary excretion (Oat5u ) was evaluated as a potential biomarker of obstructive nephropathy, comparing it with traditional markers of renal function and with neutrophil gelatinase-associated lipocalin in urine (NGALu ), a more recent biomarker of renal pathology. Bilateral ureteral obstruction (BUO) was induced in male Wistar rats, by complete ligation of ureters for 1 hour (BUO1), 2 hours (BUO2), 5 hours (BUO5), or 24 hours (BUO24). After 24 hours of ureteral releasing, urea and creatinine plasma concentrations, creatinine clearance, urinary total proteins, urinary glucose, and alkaline phosphatase activities in urine were evaluated. Oat5 and NGAL levels were assessed in urine samples by immunoblotting. All parameters of renal function were altered in the BUO24 and some also in BUO5, while the Oat5u increased in all of the experimental groups analyzed. After a long time of ureteral obstruction (BUO24), the urinary excretion of Oat5 markedly increased, in parallel with the alteration in the other parameters evaluated. Nevertheless, in BUO1 and BUO2, Oat5u appeared as the only parameter modified. Therefore, Oat5u could be proposed as a novel early biomarker of ureteral obstruction, with the additional potential to inform about the severity of the obstructive injury suffered by the kidney.
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Affiliation(s)
- Romina V Campagno
- Pharmacology Area, Faculty of Biochemistry and Pharmaceutical Sciences, National University of Rosario, CONICET, Rosario, Argentina
| | - Evangelina C Nosetto
- Pharmacology Area, Faculty of Biochemistry and Pharmaceutical Sciences, National University of Rosario, CONICET, Rosario, Argentina
| | - Anabel Brandoni
- Pharmacology Area, Faculty of Biochemistry and Pharmaceutical Sciences, National University of Rosario, CONICET, Rosario, Argentina
| | - Adriana M Torres
- Pharmacology Area, Faculty of Biochemistry and Pharmaceutical Sciences, National University of Rosario, CONICET, Rosario, Argentina
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Plasma Concentrations of Extracellular DNA in Acute Kidney Injury. Diagnostics (Basel) 2020; 10:diagnostics10030152. [PMID: 32168933 PMCID: PMC7151483 DOI: 10.3390/diagnostics10030152] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 03/02/2020] [Accepted: 03/09/2020] [Indexed: 12/18/2022] Open
Abstract
Current diagnostic methods of acute kidney injury (AKI) have limited sensitivity and specificity. Tissue injury has been linked to an increase in the concentrations of extracellular DNA (ecDNA) in plasma. A rapid turnover of ecDNA in the circulation makes it a potential marker with high sensitivity. This study aimed to analyze the concentration of ecDNA in plasma in animal models of AKI. Three different fractions of ecDNA were measured—total ecDNA was assessed fluorometrically, while nuclear ecDNA (ncDNA) and mitochondrial DNA (mtDNA) were analyzed using quantitative real-time PCR. AKI was induced using four different murine models of AKI-bilateral ureteral obstruction (BUO), glycerol-induced AKI (GLY), ischemia–reperfusion injury (IRI) and bilateral nephrectomy (BNx). Total ecDNA was significantly higher in BUO (p < 0.05) and GLY (p < 0.05) compared to the respective control groups. ncDNA was significantly higher in BUO (p < 0.05) compared to SHAM. No significant differences in the concentrations of mtDNA were found between the groups. The plasma concentrations of different fractions of ecDNA are dependent on the mechanism of induction of AKI and warrant further investigation as potential surrogate markers of AKI.
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Somparn P, Boonkrai C, Charngkaew K, Chomanee N, Hodge KG, Fenton RA, Pisitkun T, Khositseth S. Bilateral ureteral obstruction is rapidly accompanied by ER stress and activation of autophagic degradation of IMCD proteins, including AQP2. Am J Physiol Renal Physiol 2020; 318:F135-F147. [PMID: 31736351 PMCID: PMC7054639 DOI: 10.1152/ajprenal.00113.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
After the release of bilateral ureteral obstruction (BUO), postobstructive diuresis from an impaired urine concentration mechanism is associated with reduced aquaporin 2 (AQP2) abundance in the inner medullary collecting duct (IMCD). However, the underlying molecular mechanism of this AQP2 reduction is incompletely understood. To elucidate the mechanisms responsible for this phenomenon, we studied molecular changes in IMCDs isolated from rats with 4-h BUO or sham operation at the early onset of AQP2 downregulation using mass spectrometry-based proteomic analysis. Two-hundred fifteen proteins had significant changes in abundances, with 65% of them downregulated in the IMCD of 4-h BUO rats compared with sham rats. Bioinformatic analysis revealed that significantly changed proteins were associated with functional Gene Ontology terms, including “cell-cell adhesion,” “cell-cell adherens junction,” “mitochondrial inner membrane,” “endoplasmic reticulum chaperone complex,” and the KEGG pathway of glycolysis/gluconeogenesis. Targeted liquid chromatography-tandem mass spectrometry or immunoblot analysis confirmed the changes in 19 proteins representative of each predominant cluster, including AQP2. Electron microscopy demonstrated disrupted tight junctions, disorganized adherens junctions, swollen mitochondria, enlargement of the endoplasmic reticulum lumen, and numerous autophagosomes/lysosomes in the IMCD of rats with 4-h BUO. AQP2 and seven proteins chosen as representative of the significantly altered clusters had a significant increase in immunofluorescence-based colocalization with autophagosomes/lysosomes. Immunogold electron microscopy confirmed colocalization of AQP2 with the autophagosome marker microtubule-associated protein 1A/1B-light chain 3 and the lysosomal marker cathepsin D in IMCD cells of rats with 4-h BUO. We conclude that enhanced autophagic degradation of AQP2 and other critical proteins, as well as endoplasmic reticulum stress in the IMCD, are initiated shortly after BUO.
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Affiliation(s)
- Poorichaya Somparn
- Center of Excellent in Systems Biology, Research Affairs, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.,Translational Research in Inflammation and Immunology Research Unit, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Chatikorn Boonkrai
- Center of Excellent in Systems Biology, Research Affairs, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Komgrid Charngkaew
- Department of Pathology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Thailand
| | - Nusara Chomanee
- Department of Pathology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Thailand
| | - Kenneth G Hodge
- Center of Excellent in Systems Biology, 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
- Center of Excellent in Systems Biology, Research Affairs, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.,Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | - Sookkasem Khositseth
- Department of Pediatrics, Faculty of Medicine, Thammasat University, Pathumthani, Thailand
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Kim WY, Nam SA, Choi A, Kim YM, Park SH, Kim HL, Kim H, Han KH, Yang CW, Lee MS, Kim YK, Kim J. Atg7-dependent canonical autophagy regulates the degradation of aquaporin 2 in prolonged hypokalemia. Sci Rep 2019; 9:3021. [PMID: 30816234 PMCID: PMC6395725 DOI: 10.1038/s41598-019-39702-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 11/23/2018] [Indexed: 01/31/2023] Open
Abstract
Prolonged hypokalemia induces a decrease of urinary concentrating ability via down-regulation of aquaporin 2 (AQP2); however, the precise mechanisms remain unknown. To investigate the role of autophagy in the degradation of AQP2, we generated the principal cell-specific Atg7 deletion (Atg7Δpc) mice. In hypokalemic Atg7-floxed (Atg7f/f) mice, huge irregular shaped LC3-positive autophagic vacuoles accumulated mainly in inner medullary collecting duct (IMCD) cells. Total- and pS261-AQP2 were redistributed from apical and subapical domains into these vacuoles, which were not co-localized with RAB9. However, in the IMCD cells of hypokalemic Atg7Δpc mice, these canonical autophagic vacuoles were markedly reduced, whereas numerous small regular shaped LC3-negative/RAB9-positive non-canonical autophagic vacuoles were observed along with diffusely distributed total- and pS261-AQP2 in the cytoplasm. The immunoreactivity of pS256-AQP2 in the apical membrane of IMCD cells was markedly decreased, and no redistribution was observed in both hypokalemic Atg7f/f and Atg7Δpc mice. These findings suggest that AQP2 down regulation in hypokalemia was induced by reduced phosphorylation of AQP2, resulting in a reduction of apical plasma labeling of pS256-AQP2 and degradation of total- and pS261-AQP2 via an LC3/ATG7-dependent canonical autophagy pathway.
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Affiliation(s)
- Wan-Young Kim
- Department of Anatomy and Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Sun Ah Nam
- Department of Anatomy and Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Arum Choi
- Department of Anatomy and Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Yu-Mi Kim
- Department of Anatomy and Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Sang Hee Park
- Institute of Clinical Medicine Research of Bucheon St. Mary's Hospital, Bucheon, Korea
| | - Hong Lim Kim
- Integrative Research Support Center, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Hyang Kim
- Division of Nephrology, Kangbuk Samsung Hospital, Sungkyunkwan University, School of Medicine, Seoul, Korea
| | - Ki-Hwan Han
- Department of Anatomy, Ewha Womans University School of Medicine, Seoul, Korea
| | - Chul Woo Yang
- Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Myung-Shik Lee
- Severance Biomedical Science Institute, College of Medicine, Yonsei University, Seoul, Korea
| | - Yong Kyun Kim
- Department of Anatomy and Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, Seoul, Korea. .,Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
| | - Jin Kim
- Department of Anatomy and Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, Seoul, Korea.
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Farrell MR, Papagiannopoulos D, Ebersole J, White G, Deane LA. Perinephric Fat Stranding Is Associated with Elevated Creatinine Among Patients with Acutely Obstructing Ureterolithiasis. J Endourol 2018; 32:891-895. [PMID: 29943669 DOI: 10.1089/end.2018.0252] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
INTRODUCTION Pyelovenous/pyelolymphatic backflow from acute ureteral obstruction, manifesting radiologically as perinephric fat stranding (PFS), may result in elevated serum creatinine. Among patients with acutely obstructing ureterolithiasis, we evaluated the relationship between degree of PFS and changes in serum creatinine from baseline. METHODS Our tertiary care center's radiology dictation system (Fluency Discovery, M Modal) was queried for noncontrast abdominopelvic CT studies obtained in the Emergency Department for patients with obstructing ureteral calculi from 7/2015 to 4/2016. A single radiologist blinded to clinical data reviewed all CT scans and coded stone size, location, severity of hydronephrosis, and degree of PFS (none, mild, moderate, severe). For patients who met imaging criteria, a retrospective chart review was performed. RESULTS We evaluated 148 patients with mean age of 46 years (SD 14.6), 56.0% (n = 83) were male. On univariate analysis, moderate-severe perinephric stranding was associated with elevated creatinine from baseline (OR 2.93, p = 0.03). Mean creatinine increased as the severity of stranding increased (none Cr = 0.978 mg/dL, mild Cr = 0.983 mg/dL, moderate Cr = 1.165 mg/dL, severe Cr = 1.370 mg/dL; p < 0.01). An increase in creatinine from baseline was not associated with greater severity of hydronephrosis (OR 0.504, p = 0.189). There was no association between degree of PFS and severity of hydronephrosis, positive urine culture, stone location, or symptom duration (p > 0.05). On regression analysis controlling for positive urine culture and degree of hydronephrosis, there remained an association between elevated serum creatinine from baseline and moderate-severe PFS (OR 9.0, p = 0.01). CONCLUSIONS Among patients with acute obstructive ureterolithiasis, moderate-severe PFS was associated with elevated serum creatinine from baseline. This elevated creatinine was not explained by the obstructed kidney alone, as there was no association between the severity of hydronephrosis and increased creatinine. Pyelovenous/pyelolymphatic backflow resulting in PFS may be a contributing factor to elevated serum creatinine in this setting.
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Affiliation(s)
- M Ryan Farrell
- 1 Division of Urology, Rush University Medical Center , Chicago, Illinois
| | | | - John Ebersole
- 2 Department of Radiology, Rush University Medical Center , Chicago, Illinois
| | - Gregory White
- 2 Department of Radiology, Rush University Medical Center , Chicago, Illinois
| | - Leslie A Deane
- 1 Division of Urology, Rush University Medical Center , Chicago, Illinois
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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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Stødkilde L, Palmfeldt J, Nilsson L, Carlsen I, Wang Y, Nørregaard R, Frøkiaer J. Proteomic identification of early changes in the renal cytoskeleton in obstructive uropathy. Am J Physiol Renal Physiol 2014; 306:F1429-41. [PMID: 24761003 DOI: 10.1152/ajprenal.00244.2013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Bilateral ureteral obstruction (BUO) is associated with renal damage and impaired ability to concentrate urine and is known to induce alterations in an array of kidney proteins. The aim of this study was to identify acute proteomic alterations induced by BUO. Rats were subjected to BUO for 2, 6, or 24 h. Mass spectrometry-based proteomics was performed on the renal inner medulla, and protein changes in the obstructed group were identified. Significant changes were successfully identified for 109 proteins belonging to different biological classes. Interestingly, proteins belonging to the cytoskeleton and proteins related to cytoskeletal regulation were found to be biologically enriched in BUO using online-accessible tools. Western blots confirmed the selected results, demonstrating acute downregulation of proteins belonging to all three cytoskeletal components. The microfilament protein β-actin and the intermediate filament proteins pankeratin and vimentin were all downregulated. β-Tubulin, an important microtubular protein, was found to be significantly downregulated after 24 h. Also, there was significant upregulation of cofilin, an actin-binding protein known to be upregulated in other nephropathy models. Furthermore, both upregulation and downregulation of cytoskeletal motor and regulatory proteins were observed. These findings were confirmed by immunohistochemistry, which clearly showed alterations in labeling in the inner medulla. Interestingly, we were able to confirm selected results in mpkCCD cells exposed to mechanical stretch. Our findings add to the knowledge of BUO-induced acute changes in the renal cytoskeleton and suggest that these molecular changes are partly mediated by increased stretch of the cells during obstruction.
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Affiliation(s)
- Lene Stødkilde
- Department of Clinical Physiology and Molecular Imaging, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine Aarhus University Hospital, Aarhus, Denmark
| | - Johan Palmfeldt
- Research Unit for Molecular Medicine, Aarhus University Hospital, Aarhus, Denmark; and Department of Clinical Medicine Aarhus University Hospital, Aarhus, Denmark
| | - Line Nilsson
- Department of Clinical Medicine Aarhus University Hospital, Aarhus, Denmark
| | - Inge Carlsen
- Department of Clinical Physiology and Molecular Imaging, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine Aarhus University Hospital, Aarhus, Denmark
| | - Yan Wang
- Department of Clinical Physiology and Molecular Imaging, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine Aarhus University Hospital, Aarhus, Denmark
| | - Rikke Nørregaard
- Department of Clinical Medicine Aarhus University Hospital, Aarhus, Denmark
| | - Jørgen Frøkiaer
- Department of Clinical Physiology and Molecular Imaging, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine Aarhus University Hospital, Aarhus, Denmark
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15
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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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Abstract
Prostanoids are prominent, yet complex, components in the maintenance of body water homeostasis. Recent functional and molecular studies have revealed that the local lipid mediator PGE2 is involved both in water excretion and absorption. The biologic actions of PGE2 are exerted through four different G-protein-coupled receptors; designated EP1-4, which couple to separate intracellular signaling pathways. Here, we discuss new developments in our understanding of the actions of PGE2 that have been uncovered utilizing receptor specific agonists and antagonists, EP receptor and PG synthase knockout mice, polyuric animal models, and the new understanding of the molecular regulation of collecting duct water permeability. The role of PGE2 in urinary concentration comprises a variety of mechanisms, which are not fully understood and likely depend on which receptor is activated under a particular physiologic condition. EP3 and microsomal PG synthase type 1 play a role in decreasing collecting duct water permeability and increasing water excretion, whereas EP2 and EP4 can bypass vasopressin signaling and increase water reabsorption through two different intracellular signaling pathways. PGE2 has an intricate role in urinary concentration, and we now suggest how targeting specific prostanoid receptor signaling pathways could be exploited for the treatment of disorders in water balance.
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Affiliation(s)
- Emma T B Olesen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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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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Hisaki H, Matsuda J, Tadano-Aritomi K, Uchida S, Okinaga H, Miyagawa M, Tamamori-Adachi M, Iizuka M, Okazaki T. Primary polydipsia, but not accumulated ceramide, causes lethal renal damage in saposin D-deficient mice. Am J Physiol Renal Physiol 2012; 303:F1049-59. [PMID: 22832923 DOI: 10.1152/ajprenal.00047.2012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Saposin D-deficient (Sap-D(-/-)) mice develop polydipsia/polyuria and die prematurely due to renal failure with robust hydronephrosis. Such symptoms emerged when they were around 3 mo of age. To investigate the pathogenesis of their water mishandling, we attempted to limit water supply and followed sequential changes of physiological and biochemical parameters. We also analyzed renal histological changes at several time points. At 3 mo old just before water restriction challenge was started, their baseline arginine vasopressin level was comparable to the wild-type (WT) level. Twenty-four-hour water deprivation and desamino d-arginine vasopressin administration improved polydipsia and polyuria to certain degrees. However, creatinine concentrations in Sap-D(-/-) mice were significantly higher than those in WT mice, suggesting that some renal impairment already emerged in the affected mice at this age. Renal histological analyses revealed that renal tubules and collecting ducts were expanded after 3 mo old. After 6 mo old, vacuolar formation was observed, many inflammatory cells migrated around the ducts, and epithelial monolayer cells of tubular origin were replaced by plentiful cysts of various sizes. At 10∼12 mo old, severe cystic deformity appeared. On the other hand, 8-mo-long water restriction started at 4 mo old dramatically improved tubular damage and restored once-dampened amount of tubular aquaporin2 protein to the WT level. Furthermore, 10-mo-long water restriction ameliorated their renal function. Remarkably, by continuing water restriction thereafter, overall survival period became comparable with that of the WT. Together, polyuria, devastating renal tubular lesions, and renal failure were ameliorated by the mere 10-mo-long water restriction, which would trigger lethal dehydration if the disease were to be caused by any processes other than primary polydipsia. Our study demonstrates that long-term water restriction surely improved renal histopathological changes leading to prevention of premature death in Sap-D(-/-) mice.
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Affiliation(s)
- Harumi Hisaki
- Dept. of Biochemistry, Teikyo Univ. School of Medicine, Itabashi, Tokyo, Japan
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Bohn AB, Nørregaard R, Stødkilde L, Wang Y, Bertelsen LB, Fenton RA, Matchkov VV, Bouzinova EV, Horsman MR, Frøkiær J, Stødkilde-Jørgensen H. Treatment with the vascular disrupting agent combretastatin is associated with impaired AQP2 trafficking and increased urine output. Am J Physiol Regul Integr Comp Physiol 2012; 303:R186-98. [PMID: 22621967 DOI: 10.1152/ajpregu.00572.2011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Combretastatin A-4 disodium phosphate (CA4P) is a vascular disrupting agent known to mediate its effects primarily on tumor blood vessels. CA4P has previously been shown to induce a significant increase in mean arterial blood pressure and in hemoglobin concentration in mice. In the present study, we examined whether this is associated with a general leakage of water into certain tissues or with changes in renal water handling. Munich-Wistar rats received either CA4P (30 mg/kg body wt) or saline intraperitoneally as a bolus injection. One hour later, hemoglobin concentration and mean blood pressure increased significantly. MRI showed no significant changes in tissue water content following CA4P administration. However, urine output and salt excretion increased 1 h after CA4P treatment, without changes in urinary and medullary osmolality. Aquaporin 2 (AQP2) mRNA levels in kidney inner medulla did not change 1 h after CA4P treatment, but semiquantitative confocal laser-scanning microscopy analysis demonstrated a decrease in phosphorylated AQP2 (pS256-AQP2) apical distribution within the collecting ducts of CA4P-treated rats compared with the characteristic apical localization in control rats. Furthermore, we demonstrated that CA4P cause disruption of microtubules and a weaker apical labeling of pS256-AQP2 in collecting duct principal cells within 1 h. In conclusion, our data indicate that water escapes from the vascular system after CA4P treatment, and it may take place primarily through a renal mechanism. The CA4P-mediated increase in urine output seems to be a local effect in the collecting ducts due to reduced AQP2 trafficking to the apical plasma membrane.
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Affiliation(s)
- Anja B Bohn
- Department of Experimental Clinical Oncology, Aarhus University Hospital, Nørrebrogade, Denmark.
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