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Kim YJ, Oh SH, Lim JH, Cho JH, Jung HY, Kim CD, Park SH, Kwon TH, Kim YL. Impact of Ring Finger Protein 20 and Its Downstream Regulation on Renal Tubular Injury in a Unilateral Nephrectomy Mouse Model Fed a High-Fat Diet. Nutrients 2023; 15:4959. [PMID: 38068817 PMCID: PMC10708490 DOI: 10.3390/nu15234959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 11/21/2023] [Accepted: 11/23/2023] [Indexed: 12/18/2023] Open
Abstract
Abnormal lipid metabolism increases the relative risk of kidney disease in patients with a single kidney. Using transcriptome analysis, we investigated whether a high-fat diet leads to abnormalities in lipid metabolism and induces kidney cell-specific damage in unilateral nephrectomy mice. Mice with unilateral nephrectomy fed a high-fat diet for 12 weeks exhibited progressive renal dysfunction in proximal tubules, including lipid accumulation, vacuolization, and cell damage. Ring finger protein 20 (RNF20) is a ligase of nuclear receptor corepressor of peroxisome proliferator-activated receptors (PPARs). The transcriptome analysis revealed the involvement of RNF20-related transcriptome changes in PPAR signaling, lipid metabolism, and water transmembrane transporter under a high-fat diet and unilateral nephrectomy. In vitro treatment of proximal tubular cells with palmitic acid induced lipotoxicity by altering RNF20, PPARα, and ATP-binding cassette subfamily A member 1 (ABCA1) expression. PPARγ and aquaporin 2 (AQP2) expression decreased in collecting duct cells, regulating genetic changes in the water reabsorption process. In conclusion, a high-fat diet induces lipid accumulation under unilateral nephrectomy via altering RNF20-mediated regulation and causing functional damage to cells as a result of abnormal lipid metabolism, thereby leading to structural and functional kidney deterioration.
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Affiliation(s)
- You-Jin Kim
- Department of Internal Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea; (Y.-J.K.); (S.-H.O.); (J.-H.C.); (H.-Y.J.); (C.-D.K.); (S.-H.P.)
- Cell and Matrix Research Institute, Kyungpook National University, Daegu 41944, Republic of Korea
| | - Se-Hyun Oh
- Department of Internal Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea; (Y.-J.K.); (S.-H.O.); (J.-H.C.); (H.-Y.J.); (C.-D.K.); (S.-H.P.)
- Cell and Matrix Research Institute, Kyungpook National University, Daegu 41944, Republic of Korea
| | - Jeong-Hoon Lim
- Department of Internal Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea; (Y.-J.K.); (S.-H.O.); (J.-H.C.); (H.-Y.J.); (C.-D.K.); (S.-H.P.)
- Cell and Matrix Research Institute, Kyungpook National University, Daegu 41944, Republic of Korea
- Division of Nephrology, Department of Intermanl Medicine, Kyungpook National University Chilgok Hospital, Daegu 41404, Republic of Korea
| | - Jang-Hee Cho
- Department of Internal Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea; (Y.-J.K.); (S.-H.O.); (J.-H.C.); (H.-Y.J.); (C.-D.K.); (S.-H.P.)
- Cell and Matrix Research Institute, Kyungpook National University, Daegu 41944, Republic of Korea
| | - Hee-Yeon Jung
- Department of Internal Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea; (Y.-J.K.); (S.-H.O.); (J.-H.C.); (H.-Y.J.); (C.-D.K.); (S.-H.P.)
| | - Chan-Duck Kim
- Department of Internal Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea; (Y.-J.K.); (S.-H.O.); (J.-H.C.); (H.-Y.J.); (C.-D.K.); (S.-H.P.)
| | - Sun-Hee Park
- Department of Internal Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea; (Y.-J.K.); (S.-H.O.); (J.-H.C.); (H.-Y.J.); (C.-D.K.); (S.-H.P.)
| | - Tae-Hwan Kwon
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea;
| | - Yong-Lim Kim
- Department of Internal Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea; (Y.-J.K.); (S.-H.O.); (J.-H.C.); (H.-Y.J.); (C.-D.K.); (S.-H.P.)
- Cell and Matrix Research Institute, Kyungpook National University, Daegu 41944, Republic of Korea
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Qiu Z, Jiang T, Li Y, Wang W, Yang B. Aquaporins in Urinary System. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1398:155-177. [PMID: 36717493 DOI: 10.1007/978-981-19-7415-1_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
There are at least eight aquaporins (AQPs) expressed in the kidney. Including AQP1 expressed in proximal tubules, thin descending limb of Henle and vasa recta; AQP2, AQP3, AQP4, AQP5, and AQP6 expressed in collecting ducts; AQP7 expressed in proximal tubules; AQP8 expressed in proximal tubules and collecting ducts; and AQP11 expressed in the endoplasmic reticulum of proximal tubular epithelial cells. Over years, researchers have constructed different AQP knockout mice and explored the effect of AQP knockout on kidney function. Thus, the roles of AQPs in renal physiology are revealed, providing very useful information for addressing fundamental questions about transepithelial water transport and the mechanism of near isoosmolar fluid reabsorption. This chapter introduces the localization and function of AQPs in the kidney and their roles in different kidney diseases to reveal the prospects of AQPs in further basic and clinical studies.
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Affiliation(s)
- Zhiwei Qiu
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Tao Jiang
- College of Basic Medicine, Beihua University, Jilin, China
| | - Yingjie Li
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Weiling Wang
- Beijing Research Institute of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, P.R. China
| | - Baoxue Yang
- School of Basic Medical Sciences, Peking University, Beijing, China.
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Liu Z, Nanda S, Yang C, Chen S, Guo M, Khan MM, Qiu B, Zhang Y, Zhou X, Pan H. RNAi suppression of the nuclear receptor FTZ-F1 impaired ecdysis, pupation, and reproduction in the 28-spotted potato ladybeetle, Henosepilachna vigintioctopunctata. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2022; 182:105029. [PMID: 35249644 DOI: 10.1016/j.pestbp.2021.105029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 12/20/2021] [Accepted: 12/26/2021] [Indexed: 06/14/2023]
Abstract
Fushi-tarazu factor 1 (FTZF1) is an ecdysone-inducible transcription factor that plays a vital role during the metamorphosis in insects. In this study, we functionally characterized HvFTZ-F1 in H. vigintioctopunctata, a dreadful solanaceous crop pest, by using a dietary RNA interference technique. The HvFTZ-F1 expression levels were elevated in the 1st and 2nd-instars before molting and declined immediately after ecdysis. The HvFTZ-F1 silencing led to high mortality in the 1st instars, while the expression of the osmosis-regulative gene, HvAQPAn.G, was significantly increased in the 1st instars. HvFTZ-F1 silencing downregulated the Halloween and 20E-related genes, decreased the ecdysteroids titer, suppressed the expression of pigmentation-related genes, and reduced the catecholamines titer. In the 4th instars, HvFTZ-F1 silencing caused 100% mortality by arresting the development at the prepupal stage and preventing new abdominal cuticle formation. In the female adults, HvFTZ-F1 silencing caused an evident decrease in fecundity, prolonged the pre-oviposition period, reduced the number of eggs and hatching rate, severely atrophied the ovaries. Moreover, the 20E-related genes and the dopamine synthesis genes were suppressed in the dsHvFTZ-F1-treated females. Overall, our results revealed that HvFTZ-F1 regulates ecdysis, pupation, and reproduction in H. vigintioctopunctata, thereby could be a promising molecular target for the development of RNAi-based biopesticides to control H. vigintioctopunctata.
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Affiliation(s)
- Zhuoqi Liu
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou 510642, China
| | - Satyabrata Nanda
- MS Swaminathan School of Agriculture, Centurion University of Technology and Management, Odisha 761200, India
| | - Chunxiao Yang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou 510642, China
| | - Shimin Chen
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou 510642, China
| | - Mujuan Guo
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou 510642, China
| | - Muhammad Musa Khan
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou 510642, China
| | - Baoli Qiu
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou 510642, China
| | - Youjun Zhang
- Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Xuguo Zhou
- Department of Entomology, University of Kentucky, Lexington, KY 40546, USA.
| | - Huipeng Pan
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou 510642, China; State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou 510642, China.
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Olesen ETB, Fenton RA. Aquaporin 2 regulation: implications for water balance and polycystic kidney diseases. Nat Rev Nephrol 2021; 17:765-781. [PMID: 34211154 DOI: 10.1038/s41581-021-00447-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/21/2021] [Indexed: 02/06/2023]
Abstract
Targeting the collecting duct water channel aquaporin 2 (AQP2) to the plasma membrane is essential for the maintenance of mammalian water homeostasis. The vasopressin V2 receptor (V2R), which is a GS protein-coupled receptor that increases intracellular cAMP levels, has a major role in this targeting process. Although a rise in cAMP levels and activation of protein kinase A are involved in facilitating the actions of V2R, studies in knockout mice and cell models have suggested that cAMP signalling pathways are not an absolute requirement for V2R-mediated AQP2 trafficking to the plasma membrane. In addition, although AQP2 phosphorylation is a known prerequisite for V2R-mediated plasma membrane targeting, none of the known AQP2 phosphorylation events appears to be rate-limiting in this process, which suggests the involvement of other factors; cytoskeletal remodelling has also been implicated. Notably, several regulatory processes and signalling pathways involved in AQP2 trafficking also have a role in the pathophysiology of autosomal dominant polycystic kidney disease, although the role of AQP2 in cyst progression is unknown. Here, we highlight advances in the field of AQP2 regulation that might be exploited for the treatment of water balance disorders and provide a rationale for targeting these pathways in autosomal dominant polycystic kidney disease.
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Affiliation(s)
- Emma T B Olesen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark. .,Department of Endocrinology and Nephrology, North Zealand Hospital, Hillerød, Denmark.
| | - Robert A Fenton
- Department of Biomedicine, Faculty of Health, Aarhus University, Aarhus, Denmark.
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Luan ZL, Ming WH, Sun XW, Zhang C, Zhou Y, Zheng F, Yang YL, Guan YF, Zhang XY. A naturally occurring FXR agonist, alisol B 23-acetate, protects against renal ischemia-reperfusion injury. Am J Physiol Renal Physiol 2021; 321:F617-F628. [PMID: 34569253 DOI: 10.1152/ajprenal.00193.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 09/21/2021] [Indexed: 02/07/2023] Open
Abstract
The ligand-activated nuclear receptor, farnesoid X receptor (FXR), plays a pivotal role in regulating renal function. Activation of FXR by its specific agonists exerts renoprotective action in animals with acute kidney injury (AKI). In the present study, we aimed to identify naturally occurring agonists of FXR with potential as therapeutic agents in renal ischemia-reperfusion injury. In vitro and in vivo FXR activation was determined by a dual-luciferase assay, docking analysis, site-directed mutagenesis, and whole kidney transcriptome analysis. Wild-type (WT) and FXR knockout (FXR-/-) mice were used to determine the effect of potential FXR agonist on renal ischemia-reperfusion injury (IRI). We found that alisol B 23-acetate (ABA), a major active triterpenoid extracted from Alismatis rhizoma, a well-known traditional Chinese medicine, can activate renal FXR and induce FXR downstream gene expression in mouse kidney. ABA treatment significantly attenuated renal ischemia-reperfusion-induced AKI in WT mice but not in FXR-/- mice. Our results demonstrate that ABA can activate renal FXR to exert renoprotection against ischemia-reperfusion injury-induced AKI. Therefore, ABA may represent a potential therapeutic agent in the treatment of ischemic AKI.NEW & NOTEWORTHY In the present study, we found that alisol B 23-acetate (ABA), an identified natural farnesoid X receptor (FXR) agonist from the well-known traditional Chinese medicine Alismatis rhizoma, protects against ischemic acute kidney injury (AKI) in an FXR-dependent manner, as reflected by improved renal function, reduced renal tubular apoptosis, ameliorated oxidative stress, and suppressed inflammatory factor expression. Therefore, ABA may have great potential as a novel therapeutic agent in the treatment of AKI in the future.
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Affiliation(s)
- Zhi-Lin Luan
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, People's Republic of China
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Dalian Medical University, Dalian, People's Republic of China
- Dalian Key Laboratory for Nuclear Receptors in Major Metabolic Diseases, Dalian, People's Republic of China
| | - Wen-Hua Ming
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, People's Republic of China
| | - Xiao-Wan Sun
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, People's Republic of China
| | - Cong Zhang
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, People's Republic of China
| | - Yang Zhou
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, People's Republic of China
| | - Feng Zheng
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, People's Republic of China
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Dalian Medical University, Dalian, People's Republic of China
- Dalian Key Laboratory for Nuclear Receptors in Major Metabolic Diseases, Dalian, People's Republic of China
| | - Yong-Liang Yang
- Center for Molecular Medicine, School of Life Science and Biotechnology, Dalian University of Technology, Dalian, People's Republic of China
| | - You-Fei Guan
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, People's Republic of China
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Dalian Medical University, Dalian, People's Republic of China
- Dalian Key Laboratory for Nuclear Receptors in Major Metabolic Diseases, Dalian, People's Republic of China
| | - Xiao-Yan Zhang
- Health Science Center, East China Normal University, Shanghai, People's Republic of China
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Matchimakul P, Pongkan W, Kongtung P, Mektrirat R. Comparative quantitation of aquaporin-2 and arginine vasopressin receptor-2 localizations among chronic kidney disease and healthy kidney in dogs. Vet World 2021; 14:2773-2781. [PMID: 34903939 PMCID: PMC8654747 DOI: 10.14202/vetworld.2021.2773-2781] [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: 06/02/2021] [Accepted: 09/09/2021] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND AND AIM Aquaporin-2 (AQP2) and arginine vasopressin receptor-2 (AVPR2) are proteins that control water homeostasis in principal cells. Chronic kidney disease (CKD) is defined as the impairment and irreversible loss of kidney function and/or structure, which causes water imbalances and polyuria. The study aimed to know the expression of AQPs and AVPR2 in the kidneys of a canine with CKD. MATERIALS AND METHODS The kidneys were collected from two dog carcasses from Small Animal Teaching Hospital, Faculty of Veterinary Medicine, Chiang Mai University. The kidney tissue was prepared for immunohistochemistry and investigated the expression and localization of tissue's AQP2 and AVPR2. For statistical analysis, the Mann-Whitney U-test was applied to the data. RESULTS By immunohistochemistry, AQP2 was expressed strongly in the basolateral and apical membranes of the principal cells, whereas AVPR2 was localized in the principal cell's basolateral membrane in both renal cortex and renal medulla. In the normal kidney, the semi-quantitative immunohistochemistry for the percentage of protein expression of AQP2 and AVPR2 was 5.062±0.4587 and 4.306±0.7695, respectively. In contrast, protein expression of AQP2 and AVPR2 in CKD was found to be 1.218±0.1719 and 0.8536±0.1396, respectively. The data shows that the percentage of AQP2 and AVPR2 expression was decreased, corresponding to a 4-fold and 5-fold in CKD (p<0.001). CONCLUSION Our findings revealed that CKD was a marked decrease in AQP2 and AVPR2 expression. The central role of specific AQP2 and AVPR2 in regulating water homeostasis will provide correlations in case of CKD with polyuria.
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Affiliation(s)
- Pitchaya Matchimakul
- Department of Veterinary Bioscience and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
- Integrative Research Center for Veterinary Circulatory Sciences, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
| | - Wanpitak Pongkan
- Department of Veterinary Bioscience and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
- Integrative Research Center for Veterinary Circulatory Sciences, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
| | - Piyamat Kongtung
- Central Laboratory, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
| | - Raktham Mektrirat
- Department of Veterinary Bioscience and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
- Integrative Research Center for Veterinary Circulatory Sciences, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
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AQP2: Mutations Associated with Congenital Nephrogenic Diabetes Insipidus and Regulation by Post-Translational Modifications and Protein-Protein Interactions. Cells 2020; 9:cells9102172. [PMID: 32993088 PMCID: PMC7599609 DOI: 10.3390/cells9102172] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 09/22/2020] [Accepted: 09/25/2020] [Indexed: 02/07/2023] Open
Abstract
, the molecular defects in the AVPR2 and AQP2 mutants, post-translational modifications (i.e., phosphorylation, ubiquitination, and glycosylation) and various protein-protein interactions that regulate phosphorylation, ubiquitination, tetramerization, trafficking, stability, and degradation of AQP2.
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Activation of farnesoid X receptor (FXR) induces crystallin zeta expression in mouse medullary collecting duct cells. Pflugers Arch 2020; 472:1631-1641. [PMID: 32914211 DOI: 10.1007/s00424-020-02456-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 08/24/2020] [Accepted: 08/28/2020] [Indexed: 02/05/2023]
Abstract
Crystallin zeta (CRYZ) is a phylogenetically restricted water-soluble protein and provides cytoprotection against oxidative stress via multiple mechanisms. Increasing evidence suggests that CRYZ is high abundantly expressed in the kidney where it acts as a transacting factor in increasing glutaminolysis and the Na+/K+/2Cl- cotransporter (BSC1/NKCC2) expression to help maintain acid-base balance and medullary hyperosmotic gradient. However, the mechanism by which CRYZ is regulated in the kidney remains largely uncharacterized. Here, we show that CRYZ is a direct target of farnesoid X receptor (FXR), a nuclear receptor important for renal physiology. We found that CRYZ was ubiquitously expressed in mouse kidney and constitutively expressed in the cytoplasm of medullary collecting duct cells (MCDs). In primary cultured mouse MCDs, CRYZ expression was significantly upregulated by the activation and overexpression of FXR. FXR-induced CRYZ expression was almost completely abolished in the MCD cells with siRNA-mediated FXR knockdown. Consistently, treatment with FXR agonists failed to induce CRYZ expression in the MCDs isolated from mice with global and collecting duct-specific FXR deficiency. We identified a putative FXR response element (FXRE) on the CRYZ gene promoter. The luciferase reporter and ChIP assays revealed that FXR can bind directly to the FXRE site, which was further markedly enhanced by FXR activation. Furthermore, we found CRYZ overexpression in MCDs significantly attenuated hypertonicity-induced cell death possibly via increasing Bcl-2 expression. Collectively, our findings demonstrate that CRYZ is constitutively expressed in renal medullary collecting duct cells, where it is transcriptionally controlled by FXR. Given a critical role of FXR in MCDs, CRYZ may be responsible for protective effect of FXR on the survival of MCDs under hypertonic condition during dehydration.
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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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11
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Su W, Cao R, Zhang XY, Guan Y. Aquaporins in the kidney: physiology and pathophysiology. Am J Physiol Renal Physiol 2019; 318:F193-F203. [PMID: 31682170 DOI: 10.1152/ajprenal.00304.2019] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The kidney is the central organ involved in maintaining water and sodium balance. In human kidneys, nine aquaporins (AQPs), including AQP1-8 and AQP11, have been found and are differentially expressed along the renal tubules and collecting ducts with distinct and critical roles in the regulation of body water homeostasis and urine concentration. Dysfunction and dysregulation of these AQPs result in various water balance disorders. This review summarizes current understanding of physiological and pathophysiological roles of AQPs in the kidney, with a focus on recent progress on AQP2 regulation by the nuclear receptor transcriptional factors. This review also provides an overview of AQPs as clinical biomarkers and therapeutic targets for renal diseases.
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Affiliation(s)
- Wen Su
- Department of Pathophysiology, Shenzhen University Health Science Center, Shenzhen University, Shenzhen, China
| | - Rong Cao
- Department of Nephrology, The First Affiliated Hospital of Shenzhen University, Shenzhen, China.,The Second People's Hospital of Shenzhen, Shenzhen, China
| | - Xiao-Yan Zhang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, China
| | - Youfei Guan
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, China
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Bao LZ, Shen M, Qudirat H, Shi JB, Su T, Song JW, Wang ZK, Zhao XX, Jing Q, Zheng X, Guo ZF. Obestatin ameliorates water retention in chronic heart failure by downregulating renal aquaporin 2 through GPR39, V2R and PPARG signaling. Life Sci 2019; 231:116493. [PMID: 31153818 DOI: 10.1016/j.lfs.2019.05.049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 05/16/2019] [Accepted: 05/19/2019] [Indexed: 12/28/2022]
Abstract
AIMS Obestatin regulates water metabolism by inhibiting arginine vasopressin (AVP) release and upregulated obestatin has been detected in patients with chronic heart failure (CHF). However, the significance of obestatin in CHF, particularly with regard to water retention and aquaporin 2 (AQP2) expression, remains unknown. MAIN METHODS Using a CHF rat model, the effects of 2-week exogenous obestatin administration were evaluated. Expression of AQP2 was evaluated by immunoblotting, immunohistochemical staining, and quantitative real-time PCR (qPCR) in CHF rat model and mouse inner medullary collecting duct (mIMCD) 3 cell line. Moreover, the influence of obestatin on the genetic transcription profile in mIMCD3 cells was evaluated by microarray, and the potential regulatory mechanisms of obestatin on AQP2 were evaluated by RNA silencing of vasopressin receptor 2 (V2R), peroxisome proliferator-activated receptor gamma (PPARG), and G protein-coupled receptor 39 (GPR39). KEY FINDINGS Obestatin increased urinary output and improved expression of CHF biomarker without significantly altering cardiac function, plasma electrolyte concentrations, or the plasma AVP concentration. AQP2 expression was significantly reduced. The results of microarray analyses and qPCR indicated that mRNA levels of Aqp2, Pparg, and V2r were significantly decreased. Inhibition of V2r and Pparg mRNA further reduced the expression of AQP2, while the inhibitory efficacy of obestatin on AQP2 was significantly offset after Gpr39 knockdown. SIGNIFICANCE Long-term treatment with obestatin improves water retention in CHF by increasing urinary output through downregulation of AQP2 expression in renal IMCD cells. These effects may be at least partially mediated by regulation of GPR39, V2R and PPARG signaling.
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Affiliation(s)
- Li-Zhi Bao
- Department of Cardiology, Changhai Hospital, Naval Medical University, Shanghai 200433, China
| | - Ming Shen
- Department of Cardiology, Changhai Hospital, Naval Medical University, Shanghai 200433, China
| | - Hannisa Qudirat
- Department of Cardiology, Changhai Hospital, Naval Medical University, Shanghai 200433, China
| | - Jian-Bo Shi
- Department of Cardiology, HongKou Branch of Changhai Hospital of PLA, Shanghai 200081, China
| | - Ting Su
- Department of Cardiology, Changhai Hospital, Naval Medical University, Shanghai 200433, China
| | - Jing-Wen Song
- Department of Cardiology, Changhai Hospital, Naval Medical University, Shanghai 200433, China
| | - Zhong-Kai Wang
- Department of Cardiology, Changhai Hospital, Naval Medical University, Shanghai 200433, China
| | - Xian-Xian Zhao
- Department of Cardiology, Changhai Hospital, Naval Medical University, Shanghai 200433, China
| | - Qing Jing
- Department of Cardiology, Changhai Hospital, Naval Medical University, Shanghai 200433, China.
| | - Xing Zheng
- Department of Cardiology, Changhai Hospital, Naval Medical University, Shanghai 200433, China.
| | - Zhi-Fu Guo
- Department of Cardiology, Changhai Hospital, Naval Medical University, Shanghai 200433, China.
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Nawata CM, Pannabecker TL. Mammalian urine concentration: a review of renal medullary architecture and membrane transporters. J Comp Physiol B 2018; 188:899-918. [PMID: 29797052 PMCID: PMC6186196 DOI: 10.1007/s00360-018-1164-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 04/23/2018] [Accepted: 05/14/2018] [Indexed: 01/10/2023]
Abstract
Mammalian kidneys play an essential role in balancing internal water and salt concentrations. When water needs to be conserved, the renal medulla produces concentrated urine. Central to this process of urine concentration is an osmotic gradient that increases from the corticomedullary boundary to the inner medullary tip. How this gradient is generated and maintained has been the subject of study since the 1940s. While it is generally accepted that the outer medulla contributes to the gradient by means of an active process involving countercurrent multiplication, the source of the gradient in the inner medulla is unclear. The last two decades have witnessed advances in our understanding of the urine-concentrating mechanism. Details of medullary architecture and permeability properties of the tubules and vessels suggest that the functional and anatomic relationships of these structures may contribute to the osmotic gradient necessary to concentrate urine. Additionally, we are learning more about the membrane transporters involved and their regulatory mechanisms. The role of medullary architecture and membrane transporters in the mammalian urine-concentrating mechanism are the focus of this review.
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Affiliation(s)
- C Michele Nawata
- Department of Physiology, Banner University Medical Center, University of Arizona, 1501 N. Campbell Avenue, Tucson, AZ, 85724-5051, USA.
| | - Thomas L Pannabecker
- Department of Physiology, Banner University Medical Center, University of Arizona, 1501 N. Campbell Avenue, Tucson, AZ, 85724-5051, USA
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Zhang Y, Zhang GX, Wang K, Tan Y, Zhan C. Obstructive jaundice induced kidney damage is mediated by down-regulation of bile acid receptors FXR and TGR5. Shijie Huaren Xiaohua Zazhi 2018; 26:1234-1240. [DOI: 10.11569/wcjd.v26.i20.1234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM To investigate the changes in the expression of bile acid receptors FXR and TGR5 in obstructive jaundice (OJ) induced renal injury.
METHODS Twelve male Sprague-Dawley rats were randomly divided into two groups to undergo either sham operation (CON) or bile duct ligation (BDL). The animals were operated by surgical ligation of the common bile duct to establish an OJ model. Two weeks post operation, serum samples were collected to assess renal associated biochemical markers including alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bile acid (TBA), total bilirubin (TBIL), direct bilirubin (DBIL), serum urea nitrogen (BUN), creatinine (Cr), and uric acid (UA). In addition, the urine of the rats was collected for urine chemistry analysis. Transcription and translation of FXR and TGR5 genes were detected by qRT-PCR and Western blot, respectively. Tissue sections of the kidneys were stained with hematoxylin and eosin (HE) and examined for microscopically pathological changes.
RESULTS Compared with the CON group, the protein and mRNA expression of FXR and TGR5 was significantly decreased in the kidneys of the BDL rats. HE staining revealed that the kidneys of the BDL rats had decreased glomerular density and the local epithelial cells of the tubules shed. Also, the small tube lacuna was expanded, accompanied with the presence of a large number of unstructured substances.
CONCLUSION This in vivo study demonstrated significant down-regulation of the bile acid receptors FXR and TGR5 in the kidneys of OJ rats, suggesting their role in kidney damage.
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Affiliation(s)
- Yang Zhang
- Institute of Integrative Medicine, Dalian Medical University, Dalian 116044, Liaoning Province, China
| | - Gui-Xin Zhang
- Institute of Integrative Medicine, Dalian Medical University, Dalian 116044, Liaoning Province, China,Department of Acute Abdominal Surgery, the First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning Province, China
| | - Kai Wang
- Institute of Integrative Medicine, Dalian Medical University, Dalian 116044, Liaoning Province, China
| | - Yong Tan
- Institute of Integrative Medicine, Dalian Medical University, Dalian 116044, Liaoning Province, China
| | - Chen Zhan
- Institute of Integrative Medicine, Dalian Medical University, Dalian 116044, Liaoning Province, China
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15
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Abstract
Abstract
Introduction: The metanephrogenic zone, renal cortex and renal pyramids develop into their final form by week 13. The metanephric kidney produces large quantities of diluted urine in order to maintain volumes of amniotic fluid. Aquaporins are transmembrane protein channels that enable water transport through biological membranes. Aquaporin 2 (AQP2) is a water channel found in the supranuclear region and apical area of the cell membrane of the kidneys collecting tubule cells. Its main function is reabsorption of water through vasopressin stimulation.
Materials and methods: Immunohistochemistry was used to study fetal renal tissue of 34 post-mortem fetuses of 9 weeks to 24 weeks gestational age.
Results: AQP2 expression is present in connecting tubules and collecting tubules during the targeted time period. From week 9 to 12, the expression is cytoplasmic. From week 13 to 20 the enhancement of expression in the apical cell membrane occurs with the advancement of fetal age. At the end of the studied period, from week 21 to 24, both cytoplasmic and apical expression were observed. In animal studies AQP2 expression has an increasing trend during development. In contradiction with these results, other authors described low AQP2 levels in the human fetal kidney.
Conclusions: This study helps to understand the amniotic fluid’s homeostasis during pregnancy. In the beginning of the fetal period AQP2 protein is present in the cytoplasm of epithelial cells of the collecting duct and distal connecting duct. During the fetal period, AQP2 expression in collecting ducts becomes more enhanced in the apical membrane of the cells.
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16
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Lee M, Katerelos M, Gleich K, Galic S, Kemp BE, Mount PF, Power DA. Phosphorylation of Acetyl-CoA Carboxylase by AMPK Reduces Renal Fibrosis and Is Essential for the Anti-Fibrotic Effect of Metformin. J Am Soc Nephrol 2018; 29:2326-2336. [PMID: 29976587 DOI: 10.1681/asn.2018010050] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 06/18/2018] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Expression of genes regulating fatty acid metabolism is reduced in tubular epithelial cells from kidneys with tubulointerstitial fibrosis (TIF), thus decreasing the energy produced by fatty acid oxidation (FAO). Acetyl-CoA carboxylase (ACC), a target for the energy-sensing AMP-activating protein kinase (AMPK), is the major controller of the rate of FAO within cells. Metformin has a well described antifibrotic effect, and increases phosphorylation of ACC by AMPK, thereby increasing FAO. METHODS We evaluated phosphorylation of ACC in cell and mouse nephropathy models, as well as the effects of metformin administration in mice with and without mutations that reduce ACC phosphorylation. RESULTS Reduced phosphorylation of ACC on the AMPK site Ser79 occurred in both tubular epithelial cells treated with folate to mimic cellular injury and in wild-type (WT) mice after induction of the folic acid nephropathy model. When this effect was exaggerated in mice with knock-in (KI) Ser to Ala mutations of the phosphorylation sites in ACC, lipid accumulation and fibrosis increased significantly compared with WT. The effect of ACC phosphorylation on fibrosis was confirmed in the unilateral ureteric obstruction model, which showed significantly increased lipid accumulation and fibrosis in the KI mice. Metformin use was associated with significantly reduced fibrosis and lipid accumulation in WT mice. In contrast, in the KI mice, the drug was associated with worsened fibrosis. CONCLUSIONS These data indicate that reduced phosphorylation of ACC after renal injury contributes to the development of TIF, and that phosphorylation of ACC is required for metformin's antifibrotic action in the kidney.
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Affiliation(s)
- Mardiana Lee
- Kidney Laboratory, Department of Nephrology, and.,Department of Medicine, The University of Melbourne, Heidelberg and Fitzroy, Victoria, Australia
| | | | - Kurt Gleich
- Kidney Laboratory, Department of Nephrology, and
| | - Sandra Galic
- St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia; and
| | - Bruce E Kemp
- Department of Medicine, The University of Melbourne, Heidelberg and Fitzroy, Victoria, Australia.,St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia; and.,Mary MacKillop Institute for Health Research, Australian Catholic University, Fitzroy, Victoria, Australia
| | - Peter F Mount
- Kidney Laboratory, Department of Nephrology, and.,Department of Medicine, The University of Melbourne, Heidelberg and Fitzroy, Victoria, Australia.,The Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia
| | - David A Power
- Kidney Laboratory, Department of Nephrology, and .,Department of Medicine, The University of Melbourne, Heidelberg and Fitzroy, Victoria, Australia.,The Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia
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17
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Farnesoid X receptor is essential for the survival of renal medullary collecting duct cells under hypertonic stress. Proc Natl Acad Sci U S A 2018; 115:5600-5605. [PMID: 29739889 DOI: 10.1073/pnas.1803945115] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Hypertonicity in renal medulla is critical for the kidney to produce concentrated urine. Renal medullary cells have to survive high medullary osmolarity during antidiuresis. Previous study reported that farnesoid X receptor (FXR), a nuclear receptor transcription factor activated by endogenous bile acids, increases urine concentrating ability by up-regulating aquaporin 2 expression in medullary collecting duct cells (MCDs). However, whether FXR is also involved in the maintenance of cell survival of MCDs under dehydration condition and hypertonic stress remains largely unknown. In the present study, we demonstrate that 24-hours water restriction selectively up-regulated renal medullary expression of FXR with little MCD apoptosis in wild-type mice. In contrast, water deprivation caused a massive apoptosis of MCDs in both global FXR gene-deficient mice and collecting duct-specific FXR knockout mice. In vitro studies showed that hypertonicity significantly increased FXR and tonicity response enhancer binding protein (TonEBP) expression in mIMCD3 cell line and primary cultured MCDs. Activation and overexpression of FXR markedly increased cell viability and decreased cell apoptosis under hyperosmotic conditions. In addition, FXR can increase gene expression and nuclear translocation of TonEBP. We conclude that FXR protects MCDs from hypertonicity-induced cell injury very likely via increasing TonEBP expression and nuclear translocation. This study provides insights into the molecular mechanism by which FXR enhances urine concentration via maintaining cell viability of MCDs under hyperosmotic condition.
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18
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Elgot A, El Hiba O, Belkouch M, Gamrani H. The underlying physiological basis of the desert rodent Meriones shawi's survival to prolonged water deprivation: Central vasopressin regulation on peripheral kidney water channels AQPs-2. Acta Histochem 2018; 120:65-72. [PMID: 29217107 DOI: 10.1016/j.acthis.2017.11.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 11/15/2017] [Accepted: 11/17/2017] [Indexed: 12/19/2022]
Abstract
Meriones shawi (M. shawi) is a particular semi-desert rodent known by its resistance to long periods of thirst. The aim of the present investigation is to clarify the underlying mechanisms allowing M. shawi to resist to hard conditions of dehydration. For this reason we used two different approaches: i) a morphometric study, which consists in measuring the effect of dehydration on body and kidneys weights as well as the report kidney weight/body weight, ii) By immunohistochemistry, we proceed to study the effect of dehydration on the immunoreactivity of central vasopressin (AVP) and the kidney aquaporin-2 (AQP-2) which is a channel protein that allows water to permeate across cell membranes. Our results showed both a body mass decrease accompanied by a remarkable kidneys hypertrophy. The immunohistochemical study showed a significant increase of AQP-2 immunoreactivity in the medullar part of Meriones kidneys allowing probably to Meriones a great ability to water retention. Consistently, we demonstrate that the increased AQP-2 expression occurred together with an increase in vasopressin (AVP) expression in both hypothalamic supraoptic (SON) and paraventricular nucleus (PVN), which are a major hub in the osmotic control circuitry. These various changes seen either in body weight and kidneys or at the cellular level might be the basis of peripheral control of body water homeostasis, providing to M. shawia strong resistance against chronic dehydration.
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19
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Su W, Huang SZ, Gao M, Kong XM, Gustafsson JÅ, Xu SJ, Wang B, Zheng F, Chen LH, Wang NP, Guan YF, Zhang XY. Liver X receptor β increases aquaporin 2 protein level via a posttranscriptional mechanism in renal collecting ducts. Am J Physiol Renal Physiol 2017; 312:F619-F628. [PMID: 28052875 DOI: 10.1152/ajprenal.00564.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 12/19/2016] [Accepted: 12/27/2016] [Indexed: 01/22/2023] Open
Abstract
Liver X receptors (LXRs) including LXRα and LXRβ are nuclear receptor transcription factors and play an important role in lipid and glucose metabolism. It has been previously reported that mice lacking LXRβ but not LXRα develop a severe urine concentrating defect, likely via a central mechanism. Here we provide evidence that LXRβ regulates water homeostasis through increasing aquaporin 2 (AQP2) protein levels in renal collecting ducts. LXRβ-/- mice exhibited a reduced response to desmopressin (dDAVP) stimulation, suggesting that the diabetes insipidus phenotype is of both central and nephrogenic origin. AQP2 protein abundance in the renal inner medulla was significantly reduced in LXRβ-/- mice but with little change in AQP2 mRNA levels. In vitro studies showed that AQP2 protein levels were elevated upon LXR agonist treatment in both primary cultured mouse inner medullary duct cells (mIMCD) and the mIMCD3 cell line with stably expressed AQP2. In addition, LXR agonists including TO901317 and GW3965 failed to induce AQP2 gene transcription but diminished its protein ubiquitination in primary cultured mIMCD cells, thereby inhibiting its degradation. Moreover, LXR activation-induced AQP2 protein expression was abolished by the protease inhibitor MG132 and the ubiquitination-deficient AQP2 (K270R). Taken together, the present study demonstrates that activation of LXRβ increases AQP2 protein levels in the renal collecting ducts via a posttranscriptional mechanism. As such, LXRβ represents a key regulator of body water homeostasis.
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Affiliation(s)
- Wen Su
- AstraZeneca-Shenzhen University Joint Institute of Nephrology, Shenzhen University Health Science Center, Shenzhen University, Shenzhen, China
| | - Shi-Zheng Huang
- Department of Physiology and Pathophysiology, Peking University Health Science Center, Beijing, China
| | - Min Gao
- Department of Physiology and Pathophysiology, Peking University Health Science Center, Beijing, China
| | - Xiao-Mu Kong
- Department of Physiology and Pathophysiology, Peking University Health Science Center, Beijing, China
| | - Jan-Åke Gustafsson
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, Texas.,Center for Biosciences, Department of Biosciences and Nutrition, Karolinska Institutet, Novum, Stockholm, Sweden; and
| | - Su-Juan Xu
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, Liaoning, China
| | - Bing Wang
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, Liaoning, China
| | - Feng Zheng
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, Liaoning, China
| | - Li-Hong Chen
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, Liaoning, China
| | - Nan-Ping Wang
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, Liaoning, China
| | - You-Fei Guan
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, Liaoning, China
| | - Xiao-Yan Zhang
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, Liaoning, China
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20
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Barros ER, Carvajal CA. Urinary Exosomes and Their Cargo: Potential Biomarkers for Mineralocorticoid Arterial Hypertension? Front Endocrinol (Lausanne) 2017; 8:230. [PMID: 28951728 PMCID: PMC5599782 DOI: 10.3389/fendo.2017.00230] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 08/23/2017] [Indexed: 12/13/2022] Open
Abstract
Arterial hypertension (AHT) currently affects approximately 40% of adults worldwide, and its pathological mechanisms are mainly related to renal, vascular, and endocrine systems. Steroid hormones as aldosterone and cortisol are highly relevant to human endocrine physiology, and also to endocrine hypertension. Pathophysiological conditions, such as primary aldosteronism, affect approximately 10% of patients diagnosed with AHT and are secondary to a high production of aldosterone, increasing the risk also for cardiovascular damage and heart diseases. Excess of aldosterone or cortisol increases the activity of the mineralocorticoid receptor (MR) in epithelial and non-epithelial cells. Current research in this field highlights the potential regulatory mechanisms of the MR pathway, including pre-receptor regulation of the MR (action of 11BHSD2), MR activating proteins, and the downstream genes/proteins sensitive to MR (e.g., epithelial sodium channel, NCC, NKCC2). Mineralocorticoid AHT is present in 15-20% of hypertensive subjects, but the mechanisms associated to this condition have been poorly described, due mainly to the absence of reliable biomarkers. In this way, steroids, peptides, and lately urinary exosomes are thought to be potential reporters of biological processes. This review highlight exosomes and their cargo as potential biomarkers of metabolic changes associated to mineralocorticoid AHT. Recent reports have shown the presence of RNA, microRNAs, and proteins in urinary exosomes, which could be used as biomarkers in physiological and pathophysiological conditions. However, more studies are needed in order to benefit from exosomes and the exosomal cargo as a diagnostic tool in mineralocorticoid AHT.
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Affiliation(s)
- Eric R. Barros
- Center of Translational Endocrinology (CETREN), Faculty of Medicine, Endocrinology Department, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Cristian A. Carvajal
- Center of Translational Endocrinology (CETREN), Faculty of Medicine, Endocrinology Department, Pontificia Universidad Católica de Chile, Santiago, Chile
- *Correspondence: Cristian A. Carvajal,
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21
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Li Y, Wang W, Jiang T, Yang B. Aquaporins in Urinary System. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 969:131-148. [PMID: 28258571 DOI: 10.1007/978-94-024-1057-0_9] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Several aquaporin (AQP )-type water channels are expressed in kidney: AQP1 in the proximal tubule, thin descending limb of Henle, and vasa recta; AQP2 -6 in the collecting duct; AQP7 in the proximal tubule; AQP8 in the proximal tubule and collecting duct; and AQP11 in the endoplasmic reticulum of proximal tubule cells. AQP2 is the vasopressin-regulated water channel that is important in hereditary and acquired diseases affecting urine-concentrating ability. The roles of AQPs in renal physiology and transepithelial water transport have been determined using AQP knockout mouse models. This chapter describes renal physiologic insights revealed by phenotypic analysis of AQP knockout mice and the prospects for further basic and clinical studies.
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Affiliation(s)
- Yingjie Li
- Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, 100191, China
| | - Weiling Wang
- State Key Laboratory of Natural and Biomimetic Drugs, and Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, 100191, China
| | - Tao Jiang
- Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, 100191, China
| | - Baoxue Yang
- Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, 100191, China.
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing, 100191, China.
- Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Peking University, Beijing, 100191, China.
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22
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Rahman SS, Boesen EI. Outside the mainstream: novel collecting duct proteins regulating water balance. Am J Physiol Renal Physiol 2016; 311:F1341-F1345. [PMID: 27784697 DOI: 10.1152/ajprenal.00488.2016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 10/06/2016] [Accepted: 10/18/2016] [Indexed: 12/26/2022] Open
Abstract
Body water balance is critical to survival and, therefore, very tightly regulated by the hypothalamus and kidney. A key mechanism involved in this process, the arginine vasopressin-mediated phosphorylation and apical membrane insertion of aquaporin 2 in the collecting duct, has been extensively studied; however, with the increased availability of conditional knockout animals, several novel collecting duct proteins have recently been implicated in water homeostasis. In this Mini-Review, we briefly discuss these novel proteins and their roles in the regulation of water homeostasis.
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Affiliation(s)
- Shamma S Rahman
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Erika I Boesen
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska
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23
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Jung HJ, Kwon TH. Molecular mechanisms regulating aquaporin-2 in kidney collecting duct. Am J Physiol Renal Physiol 2016; 311:F1318-F1328. [PMID: 27760771 DOI: 10.1152/ajprenal.00485.2016] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 10/11/2016] [Accepted: 10/11/2016] [Indexed: 01/04/2023] Open
Abstract
The kidney collecting duct is an important renal tubular segment for regulation of body water homeostasis and urine concentration. Water reabsorption in the collecting duct principal cells is controlled by vasopressin, a peptide hormone that induces the osmotic water transport across the collecting duct epithelia through regulation of water channel proteins aquaporin-2 (AQP2) and aquaporin-3 (AQP3). In particular, vasopressin induces both intracellular translocation of AQP2-bearing vesicles to the apical plasma membrane and transcription of the Aqp2 gene to increase AQP2 protein abundance. The signaling pathways, including AQP2 phosphorylation, RhoA phosphorylation, intracellular calcium mobilization, and actin depolymerization, play a key role in the translocation of AQP2. This review summarizes recent data demonstrating the regulation of AQP2 as the underlying molecular mechanism for the homeostasis of water balance in the body.
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Affiliation(s)
- Hyun Jun Jung
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland; and
| | - Tae-Hwan Kwon
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea
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