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Calamita G, Delporte C. Insights into the Function of Aquaporins in Gastrointestinal Fluid Absorption and Secretion in Health and Disease. Cells 2023; 12:2170. [PMID: 37681902 PMCID: PMC10486417 DOI: 10.3390/cells12172170] [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: 07/01/2023] [Revised: 08/16/2023] [Accepted: 08/17/2023] [Indexed: 09/09/2023] Open
Abstract
Aquaporins (AQPs), transmembrane proteins permeable to water, are involved in gastrointestinal secretion. The secretory products of the glands are delivered either to some organ cavities for exocrine glands or to the bloodstream for endocrine glands. The main secretory glands being part of the gastrointestinal system are salivary glands, gastric glands, duodenal Brunner's gland, liver, bile ducts, gallbladder, intestinal goblet cells, exocrine and endocrine pancreas. Due to their expression in gastrointestinal exocrine and endocrine glands, AQPs fulfill important roles in the secretion of various fluids involved in food handling. This review summarizes the contribution of AQPs in physiological and pathophysiological stages related to gastrointestinal secretion.
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Affiliation(s)
- Giuseppe Calamita
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy;
| | - Christine Delporte
- Laboratory of Pathophysiological and Nutritional Biochemistry, Faculty of Medicine, Université Libre de Bruxelles, 1070 Brussels, Belgium
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Calamita G, Delporte C. Aquaporins in Glandular Secretion. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1398:225-249. [PMID: 36717498 DOI: 10.1007/978-981-19-7415-1_16] [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
Exocrine and endocrine glands deliver their secretory product, respectively, at the surface of the target organs or within the bloodstream. The release of their products has been shown to rely on secretory mechanisms often involving aquaporins (AQPs). This chapter will provide insight into the role of AQPs in secretory glands located within the gastrointestinal tract, including salivary glands, gastric glands, duodenal Brunner's glands, liver, gallbladder, intestinal goblets cells, and pancreas, as well and in other parts of the body, including airway submucosal glands, lacrimal glands, mammary glands, and eccrine sweat glands. The involvement of AQPs in both physiological and pathophysiological conditions will also be highlighted.
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Affiliation(s)
- Giuseppe Calamita
- Department of Biosciences, Biotechnologies and Environment, University of Bari "Aldo Moro", Bari, Italy
| | - Christine Delporte
- Laboratory of Pathophysiological and Nutritional Biochemistry, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium.
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Palazzo C, Abbrescia P, Valente O, Nicchia GP, Banitalebi S, Amiry-Moghaddam M, Trojano M, Frigeri A. Tissue Distribution of the Readthrough Isoform of AQP4 Reveals a Dual Role of AQP4ex Limited to CNS. Int J Mol Sci 2020; 21:ijms21041531. [PMID: 32102323 PMCID: PMC7073200 DOI: 10.3390/ijms21041531] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/14/2020] [Accepted: 02/19/2020] [Indexed: 02/06/2023] Open
Abstract
Translational readthrough (TRT) of aquaporin-4 (AQP4) has remarkably expanded the importance of this new post-transcriptional mechanism, as well as the regulation potential of AQP4. The TRT isoform of AQP4, named AQP4ex, is central for both AQP4 polarization and water channel activity in the central nervous system (CNS). Here we evaluate the relevance of the TRT mechanism by analyzing whether AQP4ex is also expressed in peripheral tissues and whether the expression of AQP4ex is necessary for its polarized expression as it occurs in perivascular astrocyte processes. To this purpose, AQP4ex null mice were used, and analysis was performed by immunolocalization and immunoblot. The results demonstrate that AQP4ex is expressed in kidney, stomach, trachea and skeletal muscle with the same localization pattern as the canonical AQP4 isoforms. AQP4ex protein levels vary from 6% to about 13% of the total AQP4 protein levels in peripheral tissues. Immunogold electron microscopy experiments demonstrated the localization of AQP4ex at the astrocytic endfeet, and experiments conducted on AQP4ex null mice CNS confirmed that the expression of AQP4ex is necessary for anchoring of the perivascular AQP4. Without the readthrough isoform, AQP4 assemblies are mis-localized, being uniformly distributed on the astrocyte processes facing the neuropile. No alteration of AQP4 polarization was found in AQP4ex null kidney, stomach, trachea or skeletal muscle, suggesting that AQP4ex does not have a role for proper membrane localization of AQP4 in peripheral tissues. We conclude that a dual role for AQP4ex is limited to the CNS.
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Affiliation(s)
- Claudia Palazzo
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (C.P.); (O.V.); (M.T.)
| | - Pasqua Abbrescia
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (C.P.); (O.V.); (M.T.)
| | - Onofrio Valente
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (C.P.); (O.V.); (M.T.)
| | - Grazia Paola Nicchia
- Department of Bioscience, Biotechnology and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy;
| | - Shervin Banitalebi
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway; (S.B.); (M.A.-M.)
| | - Mahmood Amiry-Moghaddam
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway; (S.B.); (M.A.-M.)
| | - Maria Trojano
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (C.P.); (O.V.); (M.T.)
| | - Antonio Frigeri
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (C.P.); (O.V.); (M.T.)
- Correspondence:
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Zhang J, Li S, Deng F, Baikeli B, Yu W, Liu G. Distribution of aquaporins and sodium transporters in the gastrointestinal tract of a desert hare, Lepus yarkandensis. Sci Rep 2019; 9:16639. [PMID: 31719660 PMCID: PMC6851143 DOI: 10.1038/s41598-019-53291-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 10/30/2019] [Indexed: 01/16/2023] Open
Abstract
Lepus yarkandensis is a desert hare of the Tarim Basin in western China, and it has strong adaptability to arid environments. Aquaporins (AQPs) are a family of water channel proteins that facilitate transmembrane water transport. Gastrointestinal tract AQPs are involved in fluid absorption in the small intestine and colon. This study aimed to determine the distribution of AQPs and sodium transporters in the gastrointestinal tract of L. yarkandensis and to compare the expression of these proteins with that in Oryctolagus cuniculus. Immunohistochemistry was performed to analyse the cellular distribution of these proteins, and the acquired images were analysed with IpWin32 software. Our results revealed that AQP1 was located in the colonic epithelium, central lacteal cells, fundic gland parietal cells, and capillary endothelial cells; AQP3 was located in the colonic epithelium, small intestinal villus epithelium, gastric pit and fundic gland; AQP4 was located in the fundic gland, small intestinal gland and colonic epithelium; and epithelial sodium channel (ENaC) and Na+-K+-ATPase were located in the epithelial cells, respectively. The higher expression levels of AQP1, AQP3, ENaC and Na+-K+-ATPase in the colon of L. yarkandensis compared to those in O. cuniculus suggested that L. yarkandensis has a higher capacity for faecal dehydration.
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Affiliation(s)
- Jianping Zhang
- College of Life Science, Tarim University Alar, Xinjiang Province, 843300, People's Republic of China.
- Key Laboratory of Biological Resources Protection and Utilization in Tarim Basin, Tarim University Alar, Xinjiang Province, 843300, People's Republic of China.
- Department of Biochemistry and Molecular Biology, School of Laboratory Medicine, and Anhui Province Key Laboratory of Translational Cancer Research Bengbu Medical College Bengbu, Anhui Province, 233030, People's Republic of China.
| | - Shuwei Li
- College of Life Science, Tarim University Alar, Xinjiang Province, 843300, People's Republic of China
- Key Laboratory of Biological Resources Protection and Utilization in Tarim Basin, Tarim University Alar, Xinjiang Province, 843300, People's Republic of China
| | - Fang Deng
- College of Life Science, Tarim University Alar, Xinjiang Province, 843300, People's Republic of China
| | - Buheliqihan Baikeli
- College of Life Science, Tarim University Alar, Xinjiang Province, 843300, People's Republic of China
| | - Weijiang Yu
- College of Life Science, Tarim University Alar, Xinjiang Province, 843300, People's Republic of China
| | - Guoquan Liu
- Department of Biochemistry and Molecular Biology, School of Laboratory Medicine, and Anhui Province Key Laboratory of Translational Cancer Research Bengbu Medical College Bengbu, Anhui Province, 233030, People's Republic of China.
- Department of Basic Veterinary Medicine, and Key Lab of Swine Genetics and Breeding and Agricultural Animal Breeding and Reproduction, College of Animal Science and Veterinary Medicine Huazhong Agricultural University Wuhan, Hubei Province, 430070, People's Republic of China.
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Abstract
Aquaporins (AQPs ) are expressed in most exocrine and endocrine secretory glands. Consequently, summarizing the expression and functions of AQPs in secretory glands represents a daunting task considering the important number of glands present in the body, as well as the number of mammalian AQPs - thirteen. The roles played by AQPs in secretory processes have been investigated in many secretory glands. However, despite considerable research, additional studies are clearly needed to pursue our understanding of the role played by AQPs in secretory processes. This book chapter will focus on summarizing the current knowledge on AQPs expression and function in the gastrointestinal tract , including salivary glands, gastric glands, Duodenal Brunner's gland, liver and gallbladder, intestinal goblets cells, exocrine and endocrine pancreas, as well as few other secretory glands including airway submucosal glands, lacrimal glands, mammary glands and eccrine sweat glands.
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Affiliation(s)
- Christine Delporte
- Laboratory of Pathophysiological and Nutritional Biochemistry, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium.
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Expression, Distribution and Role of Aquaporin Water Channels in Human and Animal Stomach and Intestines. Int J Mol Sci 2016; 17:ijms17091399. [PMID: 27589719 PMCID: PMC5037679 DOI: 10.3390/ijms17091399] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 08/09/2016] [Accepted: 08/22/2016] [Indexed: 12/22/2022] Open
Abstract
Stomach and intestines are involved in the secretion of gastrointestinal fluids and the absorption of nutrients and fluids, which ensure normal gut functions. Aquaporin water channels (AQPs) represent a major transcellular route for water transport in the gastrointestinal tract. Until now, at least 11 AQPs (AQP1–11) have been found to be present in the stomach, small and large intestines. These AQPs are distributed in different cell types in the stomach and intestines, including gastric epithelial cells, gastric glands cells, absorptive epithelial cells (enterocytes), goblet cells and Paneth cells. AQP1 is abundantly distributed in the endothelial cells of the gastrointestinal tract. AQP3 and AQP4 are mainly distributed in the basolateral membrane of epithelial cells in the stomach and intestines. AQP7, AQP8, AQP10 and AQP11 are distributed in the apical of enterocytes in the small and large intestines. Although AQP-null mice displayed almost no phenotypes in gastrointestinal tracts, the alterations of the expression and localization of these AQPs have been shown to be associated with the pathology of gastrointestinal disorders, which suggests that AQPs play important roles serving as potential therapeutic targets. Therefore, this review provides an overview of the expression, localization and distribution of AQPs in the stomach, small and large intestine of human and animals. Furthermore, this review emphasizes the potential roles of AQPs in the physiology and pathophysiology of stomach and intestines.
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Expression of aquaporin-4 water channels in the digestive tract of the guinea pig. J Mol Histol 2013; 45:229-41. [DOI: 10.1007/s10735-013-9545-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 10/03/2013] [Indexed: 01/14/2023]
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Shen L, Zhu Z, Huang Y, Shu Y, Sun M, Xu H, Zhang G, Guo R, Wei W, Wu W. Expression profile of multiple aquaporins in human gastric carcinoma and its clinical significance. Biomed Pharmacother 2010; 64:313-8. [PMID: 20106632 DOI: 10.1016/j.biopha.2009.12.003] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Accepted: 12/01/2009] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND New evidence for involvement of aquaporins (AQPs) in cell migration and proliferation adds AQPs to an expanding list of effectors in tumor biology. But there is few report concerning the expression and role of AQPs in human gastric carcinogenesis so far. The aim of this current study was to investigate the expression profile of AQPs in human gastric carcinoma and its significance. METHODS We screened the expression profile of AQP0 approximately AQP12 in gastric adenocarcinoma tissues and corresponding normal mucosa from 89 patients with gastric cancer by reverse transcriptase polymerase chain reaction (RT-PCR), Western blot analysis and immunochemical assay. The relationship between AQPs expression and clinicopathologic characteristics of patients was evaluated. RESULTS Based on RT-PCR of 13 AQPs examined, AQP1, 3, 4, 5 and 11 were expressed in human gastric cancers or normal gastric tissues, and AQP3, 4 and 5 exhibited differential expression between human gastric carcinomas and corresponding normal tissues, which was confirmed by Western blot analyses. Immunohistochemical assay showed that AQP4 protein was expressed mainly in the membrane of parietal cell and chief cell in the normal gastric mucosa, and absent in carcinoma tissues. AQP3 and AQP5 were detected remarkably stronger in the carcinoma tissues than that in normal mucosa by immunofluorescence. AQP3 expression in cases with undifferentiated tumor was more than that in cases with well-differentiated tumor. Both AQP3 and AQP5 expression were associated with lymph node metastasis and lymphovascular invasion in patients. CONCLUSIONS These findings of differential expressions of AQPs and their correlation with clinicopathologic characteristics implicated AQPs might play a role in human gastric carcinogenesis.
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Affiliation(s)
- Lizong Shen
- Department of General Surgery, First Affiliated Hospital, Nanjing Medical University, 300 Guangzhou Road, Nanjing, Jiangsu 210029, PR China.
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Van Hoek AN, Bouley R, Lu Y, Silberstein C, Brown D, Wax MB, Patil RV. Vasopressin-induced differential stimulation of AQP4 splice variants regulates the in-membrane assembly of orthogonal arrays. Am J Physiol Renal Physiol 2009; 296:F1396-404. [PMID: 19297454 DOI: 10.1152/ajprenal.00018.2009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Aquaporin-4 (AQP4) is a basolateral water channel in collecting duct principal cells and assembles into orthogonal array particles (OAPs), the size of which appears to depend on relative expression levels of AQP4 splice variants. Because the higher-order organization of AQP4 was perturbed by vasopressin in Brattleboro rats and phosphorylation sites have been identified on AQP4, we investigated whether vasopressin and forskolin (Fk) affect AQP4 assembly and/or expression in LLC-PK(1) cells stably transfected with the AQP4 splice variant M23, which is responsible for formation of OAPs, and/or the splice variant M1, which does not form OAPs. Our data show that [lys(8)]-vasopressin (LVP) and Fk treatment led to differential increases in expression levels of M23-AQP4 and M1-AQP4 that varied as a function of incubation time. At early time points (day 1) expression of M1 was significantly stimulated (4.5-fold), over that of M23 (1.6-fold), but after 3 days the expression of M23 became predominant (4.1-fold) over that of M1 (1.9-fold). This pattern of stimulation was dependent on an intact AQP4 residue serine 111 and required protein synthesis. In cells expressing both M1 and M23 (M1/M23 approximately 1), with small sized OAPs at the membrane, the LVP/Fk-induced stimulation of M23 was modified and mimicked that of M1 when expressed alone, suggesting a dominant role for M1. In Brattleboro kidney inner medulla, an 8-day chronic exposure to the vasopressin agonist (dDAVP) led to reduction in M1 and a significant increase in M23 immunoblot staining (M1/M23 = 2/3 --> 1/4). These results indicate that AQP4 organization and expression are regulated by vasopressin in vivo and in vitro and demonstrate that the dominant role for M1 is restricted to a one-to-one interaction between AQP4 splice variants that regulates the membrane expression of OAPs.
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Affiliation(s)
- Alfred N Van Hoek
- Simches Research Center, 8.208, 185 Cambridge St., Boston, MA 02114, USA.
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Abstract
In this article, key concepts in gastric anatomy and physiology are reviewed. Attention is given to historical development of concepts of acid secretion, to the role of stomach in digestion, and to the mechanisms that protect gastric mucosa from acid and hostile luminal conditions. Evolving ideas that may influence understand-ing of the physiologic consequences of emerging therapeutics, and procedures that target anatomy or function of the stomach are also reviewed.
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Affiliation(s)
- David I Soybel
- Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street Boston, MA 02115, USA.
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Silberstein C, Bouley R, Huang Y, Fang P, Pastor-Soler N, Brown D, Van Hoek AN. Membrane organization and function of M1 and M23 isoforms of aquaporin-4 in epithelial cells. Am J Physiol Renal Physiol 2004; 287:F501-11. [PMID: 15149973 DOI: 10.1152/ajprenal.00439.2003] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Aquaporin-4 (AQP4) water channels exist as heterotetramers of M1 and M23 splice variants and appear to be present in orthogonal arrays of intramembraneous particles (OAPs) visualized by freeze-fracture microscopy. We report that AQP4 forms OAPs in rat gastric parietal cells but not in parietal cells from the mouse or kangaroo rat. Furthermore, the organization of principal cell OAPs in Brattleboro rat kidney is perturbed by vasopressin (arginine vasopressin). Membranes of LLC-PK1cells expressing M23-AQP4 showed large, abundant OAPs, but none were detectable in cells expressing M1-AQP4. Measurements of osmotic swelling of transfected LLC-PK1cells using videomicroscopy, gave osmotic water permeability coefficient ( Pf) values (in cm/s) of 0.018 (M1-AQP4), 0.019 (M23-AQP4), and 0.003 (control). Quantitative immunoblot and immunofluorescence showed an eightfold greater expression of M1- over M23-AQP4 in the cell lines, suggesting that single-channel pf(cm3/s) is much greater for the M23 variant. Somatic fusion of M1- and M23-AQP4 cells ( Pf= 0.028 cm/s) yielded OAPs that were fewer and smaller than in M23 cells alone, and M1-to-M23 expression ratios (∼1:4) normalized to AQP4 in M1 or M23 cells indicated a reduced single-channel pffor the M23 variant. Expression of an M23-AQP4-Ser111Emutant produced ∼1.5-fold greater single-channel pfand OAPs that were up to 2.5-fold larger than wild-type M23-AQP4 OAPs, suggesting that a putative PKA phosphorylation site Ser111is involved in OAP formation. We conclude that the higher-order organization of AQP4 in OAPs increases single-channel osmotic water permeability by one order of magnitude and that differential cellular expression levels of the two isoforms could regulate this organization.
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Affiliation(s)
- Claudia Silberstein
- Renal Unit and Program in Membrane Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA
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