A water channel closely related to rat brain aquaporin 4 is expressed in acid‐ and pepsinogen‐secretory cells of human stomach

Misaka, Takumi; Abe, Keiko; Iwabuchi, Kyoko; Kusakabe, Yuko; Ichinose, Masakazu; Miki, Kazumasa; Emori, Yasufumi; Arai, Soichi

doi:10.1016/0014-5793(96)00092-0

Cited by 57 publications

(41 citation statements)

References 22 publications

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“…First of all, in the present study we were unable to localize AQP4 in any of the cells of different regions of the porcine stomach (cardia, fundus, body, and pylorus). In previous studies, the expression of AQP4 was detected at basolateral membrane of parietal cells located in the stomach of the rat (Fujita et al 1999), mouse (Wang et al 2000), guinea pig (Jiang et al 2014) and humans (Misaka et al 1996). Since the application of proton pump inhibitors evoking acid suppression substantially increased the number of fundic AQP4-expressing parietal cells in the mouse, the involvement of aquaporin in gastric secretory processes (acid secretion) has been postulated (Matsuzaki et al 2010).…”

Section: Discussionmentioning

confidence: 99%

Immunohistochemical localization of aquaporin 4 (AQP4) in the porcine gastrointestinal tract

2015

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The water channel aquaporin-4 (AQP4) is a protein widely expressed on plasma membrane of a variety of epithelial cells. In this study we investigated the expression of AQP4 in the gastrointestinal tract of the pig using immunohistochemical staining. We found no presence of AQP4 in the different regions of the pig stomach. In the porcine small intestine moderate immunoreactivity to AQP4 was detected in enterocytes (along the villi and in the bottom of the crypts), duodenal Brunner's glands and in enteric ganglia in cells lying in close vicinity to myenteric as well as submucous neurons. In superficial epithelial cells of the colonic mucosa as well as of caecal and colonic glands a very strong immunoreactivity to AQP4 was found. Both in the myenteric and submucous ganglia of the large intestine AQP4-positive cells surrounding enteric neurons were observed. We concluded that AQP4 expression in the porcine gastrointestinal tract showed some species-dependent differences in relation to other species. Based on the presented distribution pattern of AQP4, it is likely that the aquaporin plays a role in mucous (but not acid) secretion and intestinal absorptive processes in the pig. Aquaporins, gut, small intestine, large intestine, pig

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Section: Discussionmentioning

confidence: 99%

Immunohistochemical localization of aquaporin 4 (AQP4) in the porcine gastrointestinal tract

2015

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“…AQP4 is an efficient water-selective transporting protein that does not carry protons, ions, or other small solutes (26). AQP4 was originally cloned from rat lung (27), and subsequently various isoforms in brain (28), stomach (29) and other mammals have been sequenced. Knockout mice lacking AQP4 manifest a mild urinary concentrating defect (18) because of impaired water transport in the inner medullary collecting duct (30).…”

Section: Discussionmentioning

confidence: 99%

Impaired Hearing in Mice Lacking Aquaporin-4 Water Channels

Verkman

2001

Journal of Biological Chemistry

239

154

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A role for aquaporins (AQPs) in hearing has been suggested from the specific expression of aquaporins in inner ear and the need for precise volume regulation in epithelial cells involved in acoustic signal transduction. Using mice deficient in selected aquaporins as controls, we localized AQP1 in fibrocytes in the spiral ligament and AQP4 in supporting epithelial cells (Hensen's, Claudius, and inner sulcus cells) in the organ of Corti. To determine whether aquaporins play a role in hearing, auditory brain stem response (ABR) thresholds were compared in wild-type mice and transgenic null mice lacking (individually) AQP1, AQP3, AQP4, and AQP5. In 4 -5-week-old mice in a CD1 genetic background, ABR thresholds in response to a click stimulus were remarkably increased by >12 db in AQP4 null mice compared with wild-type mice (p < 0.001), whereas ABR thresholds were not affected by AQP1, AQP3, or AQP5 deletion. In a C57/bl6 background, nearly all AQP4 null mice were deaf, whereas ABRs could be elicited in wildtype controls. ABRs in AQP4 null CD1 mice measured in response to tone bursts (4 -20 kHz) indicated a frequency-independent hearing deficit. Light microscopy showed no differences in cochlear morphology of wildtype versus AQP4 null mice. These results provide the first direct evidence that an aquaporin water channel plays a role in hearing. AQP4 may facilitate rapid osmotic equilibration in epithelial cells in the organ of Corti, which are subject to large K ؉ fluxes during mechano-electric signal transduction.The aquaporins (AQPs) 1 are a family of small integral membrane proteins that function as water transporters. Phenotype analysis of mice lacking aquaporins has indicated that they play a physiological role in the kidney, central nervous system, gastrointestinal system, and exocrine glands (reviewed in Ref. 1). Mice lacking AQP1, AQP2, or AQP3 manifest nephrogenic diabetes insipidus with defective urinary concentrating ability (2-4), mice lacking AQP4 have altered brain water balance in response to injury (5), and mice lacking AQP5 have defective saliva secretion (6). In humans, mutations in AQP2 cause the autosomal form of hereditary nephrogenic diabetes insipidus (7). Phenotype studies have also shown the tissue-specific expression of an aquaporin does not prove its physiological importance. For example, mice lacking AQP4 in gastric parietal cells and skeletal muscle have unimpaired stomach acid secretion (8) and skeletal muscle function (9). The data from aquaporin null mice suggest that aquaporins are functionally important in tissues carrying out rapid near isosmolar fluid transport or passive water transport driven by osmotic gradients (1).Several aquaporins have been localized in the mammalian inner ear and have been proposed to play a role in hearing. Reverse transcriptase polymerase chain reaction analysis of dissected rat inner ear showed diffuse AQP1 transcript expression, specific expression of AQP2, AQP3, and AQP4 in the endolymphatic sac, and expression of AQP5 in the organ of Corti and Reissn...

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“…AQPs play a pivotal role for normal gastrointestinal homeostasis, all from the secretion of saliva where AQP5 plays an important role [191][192][193], through the water-tight regulated stomach where AQP1, 3 and 4 play major roles in the secretion of gastric juices [189,[194][195][196] and the small intestine, where enterocytes immense bidirectional water transport where AQP1, 3, 7, 10 and 11 are expressed [189,195,197] to the ascending colon where primarily AQP1, 3, 7, 8 and 11 are present [198][199][200]. Several studies have displayed the importance of AQPs in faecal concentration/water absorption in the colon.…”

Section: Aquaporins In Gastrointestinal Homeostasis and Diarrhoeamentioning

confidence: 99%

Aquaporins in Infection and Inflammation

Holm¹

2016

Linköping University Medical Dissertations

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About the cover:The front cover displays a human, blood-derived macrophage stained for aquaporin 9.During the course of the research underlying this thesis, Angelika Holm was enrolled in Forum Scientium, a multidisciplinary doctoral programme at Linköping University Printed by LiU-Tryck, Linköping, Sweden, 2016 "Be brave, even if you're not, pretend to be. No one can tell the difference."To that young, awkward, tall girl who dared to dream of something else, something more:You did it. SUPERVISOR Elena VikströmDepartment of Clinical and Experimental Medicine Linköping University Linköping Sweden When cells of the innate immune system encounter pathogens they need to respond and prepare for migration and phagocytosis and do so through volume regulatory processes. The Gramnegative bacterium Pseudomonas aeruginosa utilizes a small molecule-based communication system, called quorum sensing (QS) to control the production of its virulence factors and biofilms. We found that P. aeruginosa with a complete QS system elicits a stronger phagocytic response in human blood-derived macrophages compared to its lasI-/rhlI-mutant lacking the production of the QS molecules N-butyryl-L-homoserine lactone (C4-HSL) and N-3-oxododecanoyl-L-homoserine lactone (3O-C12-HSL). Infection with P. aeruginosa further increases the expression of AQP9 and induces re-localisation of AQP9 to the front and trailing ends of macrophages. Moreover, the 3O-C12-HSL alone elevates the expression of AQP9, redistribute the water channel to the front and rear ends and increases the cell area and volume of macrophages. Both infection with the wild type P. aeruginosa and the treatment with 3O-C12-HSL change the nano-structural architecture of the AQP9 distribution in macrophages. ASSISTANT SUPERVISORS Karl-Eric MagnussonViruses use the intracellular machinery of the invaded cells to produce and assemble new viral bodies. Intracellular AQPs are localised in a membranes of cellular organelles to regulate their function and morphology. C3H10T1/2 fibroblasts transiently expressing green fluorescent protein (GFP)-AQP6 show a reduced expression of AQP6 after Hazara virus infection and an increased cell area. Overexpressing AQP6 in C3H10T1/2 cells reduces the infectivity of Hazara virus indicating that AQP6 expression has a protective role in virus infections.Ion and water channels in the epithelial cell lining tightly regulate the water homeostasis. In microscopic colitis (MC), patients suffer from severe watery diarrhoeas. For the first time, we have shown that the expression of AQP1, 8 and 11 and the sodium/hydrogen exchanger NHE1 are reduced in colonic biopsies from MC patients compared to healthy control individuals. Following treatment with the glucocorticoid budesonide the patients experienced a rapid recovery and we observed a restored or increased expression of the AQPs and NHE1 during treatment, suggesting a role for AQPs in the diarrhoeal mechanisms in MC.Taken together, this thesis provides new evidence on the importance of water homeostasis regulatio...

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A water channel closely related to rat brain aquaporin 4 is expressed in acid‐ and pepsinogen‐secretory cells of human stomach

Cited by 57 publications

References 22 publications

Immunohistochemical localization of aquaporin 4 (AQP4) in the porcine gastrointestinal tract

Immunohistochemical localization of aquaporin 4 (AQP4) in the porcine gastrointestinal tract

Impaired Hearing in Mice Lacking Aquaporin-4 Water Channels

Aquaporins in Infection and Inflammation

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