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Wan H, Li J, Chen X, Sellers ZM, Dong H. Divergent roles of estrogen receptor subtypes in regulating estrogen-modulated colonic ion transports and epithelial repair. J Biol Chem 2023; 299:105068. [PMID: 37468102 PMCID: PMC10448179 DOI: 10.1016/j.jbc.2023.105068] [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: 06/12/2023] [Revised: 07/10/2023] [Accepted: 07/12/2023] [Indexed: 07/21/2023] Open
Abstract
Although it was described previously for estrogen (E2) regulation of intestinal epithelial Cl- and HCO3- secretion in sex difference, almost nothing is known about the roles of estrogen receptor (ER) subtypes in regulating E2-modulated epithelial ion transports and epithelial restitution. Here, we aimed to investigate ERα and ERβ subtypes in the regulation of E2-modulated colonic epithelial HCO3- and Cl- secretion and epithelial restitution. Through physiological and biochemical studies, in combination of genetic knockdown, we showed that ERα attenuated female colonic Cl- secretion but promoted Ca2+-dependent HCO3- secretion via store-operated calcium entry (SOCE) mechanism in mice. However, ERβ attenuated HCO3- secretion by inhibiting Ca2+via the SOCE and inhibiting cAMP via protein kinases. Moreover, ERα but not ERβ promoted epithelial cell restitution via SOCE/Ca2+ signaling. ERα also enhanced cyclin D1, proliferating cell nuclear antigen, and β-catenin expression in normal human colonic epithelial cells. All ERα-mediated biological effects could be attenuated by its selective antagonist and genetic knockdown. Finally, both ERα and ERβ were expressed in human colonic epithelial cells and mouse colonic tissues. We therefore conclude that E2 modulates complex colonic epithelial HCO3- and Cl- secretion via ER subtype-dependent mechanisms and that ERα is specifically responsible for colonic epithelial regeneration. This study provides novel insights into the molecular mechanisms of how ERα and ERβ subtypes orchestrate functional homeostasis of normal colonic epithelial cells.
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Affiliation(s)
- Hanxing Wan
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao, China; Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Junhui Li
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao, China
| | - Xiongying Chen
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao, China
| | - Zachary M Sellers
- Pediatric Gastroenterology Hepatology & Nutrition, Stanford University School of Medicine, Palo Alto, California, USA.
| | - Hui Dong
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao, China.
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2
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Whittamore JM, Hatch M. Oxalate Flux Across the Intestine: Contributions from Membrane Transporters. Compr Physiol 2021; 12:2835-2875. [PMID: 34964122 DOI: 10.1002/cphy.c210013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Epithelial oxalate transport is fundamental to the role occupied by the gastrointestinal (GI) tract in oxalate homeostasis. The absorption of dietary oxalate, together with its secretion into the intestine, and degradation by the gut microbiota, can all influence the excretion of this nonfunctional terminal metabolite in the urine. Knowledge of the transport mechanisms is relevant to understanding the pathophysiology of hyperoxaluria, a risk factor in kidney stone formation, for which the intestine also offers a potential means of treatment. The following discussion presents an expansive review of intestinal oxalate transport. We begin with an overview of the fate of oxalate, focusing on the sources, rates, and locations of absorption and secretion along the GI tract. We then consider the mechanisms and pathways of transport across the epithelial barrier, discussing the transcellular, and paracellular components. There is an emphasis on the membrane-bound anion transporters, in particular, those belonging to the large multifunctional Slc26 gene family, many of which are expressed throughout the GI tract, and we summarize what is currently known about their participation in oxalate transport. In the final section, we examine the physiological stimuli proposed to be involved in regulating some of these pathways, encompassing intestinal adaptations in response to chronic kidney disease, metabolic acid-base disorders, obesity, and following gastric bypass surgery. There is also an update on research into the probiotic, Oxalobacter formigenes, and the basis of its unique interaction with the gut epithelium. © 2021 American Physiological Society. Compr Physiol 11:1-41, 2021.
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Affiliation(s)
- Jonathan M Whittamore
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Marguerite Hatch
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, Florida, USA
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3
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Nortunen M, Parkkila S, Saarnio J, Huhta H, Karttunen TJ. Carbonic Anhydrases II and IX in Non-ampullary Duodenal Adenomas and Adenocarcinoma. J Histochem Cytochem 2021; 69:677-690. [PMID: 34636283 DOI: 10.1369/00221554211050133] [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] [Indexed: 12/16/2022] Open
Abstract
Non-ampullary duodenal adenocarcinoma (DAC) is a rare malignancy. Little information is available concerning the histopathological prognostic factors associated with DAC. Carbonic anhydrases (CAs) are metalloenzymes catalyzing the universal reaction of CO2 hydration. Isozymes CAII, CAIX, and CAXII are associated with prognosis in various cancers. Our aim was to analyze the immunohistochemical expressions of CAII, CAIX, and CAXII in normal duodenal epithelium, duodenal adenomas, and adenocarcinoma and their associations with clinicopathological variables and survival. Our retrospective study included all 27 DACs treated in Oulu University Hospital during years 2000-2020. For comparison, samples of 42 non-ampullary adenomas were collected. CAII expression was low in duodenal adenomas and adenocarcinoma. CAIX expression in adenomas and adenocarcinoma was comparable with the high expression of normal duodenal crypts. Expression patterns in carcinomas were largely not related to clinicopathological features. However, low expression of CAII associated with poorer differentiation of the tumor (p=0.049) and low expression of CAIX showed a trend for association with nodal spread, although statistical significance was not reached (p=0.091). CAII and CAIX lost their epithelial polarization and staining intensity in adenomas. CAXII expression was not detected in the studied samples. CAs were not associated with survival. The prognostic value of CAII and CAIX downregulation should be further investigated. Both isozymes may serve as biomarkers of epithelial dysplasia in the duodenum.
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Affiliation(s)
- Minna Nortunen
- Research Unit of Surgery, Anesthesia and Intensive Care, University of Oulu, Oulu, Finland.,Department of Surgery, Oulu University Hospital and Medical Research Center Oulu, Oulu, Finland.,Cancer and Translational Medicine Research Unit, Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Seppo Parkkila
- Faculty of Medicine and Health Technology, Tampere University and Fimlab Ltd, Tampere University Hospital, Tampere, Finland (SP)
| | - Juha Saarnio
- Research Unit of Surgery, Anesthesia and Intensive Care, University of Oulu, Oulu, Finland.,Department of Surgery, Oulu University Hospital and Medical Research Center Oulu, Oulu, Finland.,Cancer and Translational Medicine Research Unit, Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Heikki Huhta
- Research Unit of Surgery, Anesthesia and Intensive Care, University of Oulu, Oulu, Finland.,Department of Surgery, Oulu University Hospital and Medical Research Center Oulu, Oulu, Finland.,Cancer and Translational Medicine Research Unit, Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Tuomo J Karttunen
- Cancer and Translational Medicine Research Unit, Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
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4
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The role of HCO 3- in propionate-induced anion secretion across rat caecal epithelium. Pflugers Arch 2021; 473:937-951. [PMID: 33914143 PMCID: PMC8164622 DOI: 10.1007/s00424-021-02565-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/29/2021] [Accepted: 04/08/2021] [Indexed: 12/25/2022]
Abstract
Propionate, a metabolite from the microbial fermentation of carbohydrates, evokes a release of epithelial acetylcholine in rat caecum resulting in an increase of short-circuit current (Isc) in Ussing chamber experiments. The present experiments were performed in order to characterize the ionic mechanisms underlying this response which has been thought to be due to Cl− secretion. As there are regional differences within the caecal epithelium, the experiments were conducted at oral and aboral rat corpus caeci. In both caecal segments, the propionate-induced Isc (IProp) was inhibited by > 85%, when the experiments were performed either in nominally Cl−- or nominally HCO3−-free buffer. In the case of Cl−, the dependency was restricted to the presence of Cl− in the serosal bath. Bumetanide, a blocker of the Na+-K+-2Cl−-cotransporter, only numerically reduced IProp suggesting that a large part of this current must be carried by an ion other than Cl−. In the aboral caecum, IProp was significantly inhibited by mucosally administered stilbene derivatives (SITS, DIDS, DNDS), which block anion exchangers. Serosal Na+-free buffer reduced IProp significantly in the oral (and numerically also in aboral) corpus caeci. RT-PCR experiments revealed the expression of several forms of Na+-dependent HCO3−-cotransporters in caecum, which might underlie the observed Na+ dependency. These results suggest that propionate sensing in caecum is coupled to HCO3– secretion, which functionally would stabilize luminal pH when the microbial fermentation leads to an increase in the concentration of short-chain fatty acids in the caecal lumen.
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5
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Gaowa N, Li W, Murphy B, Cox MS. The Effects of Artificially Dosed Adult Rumen Contents on Abomasum Transcriptome and Associated Microbial Community Structure in Calves. Genes (Basel) 2021; 12:424. [PMID: 33809523 PMCID: PMC7999174 DOI: 10.3390/genes12030424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/08/2021] [Accepted: 03/09/2021] [Indexed: 01/20/2023] Open
Abstract
This study aimed to investigate the changes in abomasum transcriptome and the associated microbial community structure in young calves with artificially dosed, adult rumen contents. Eight young bull calves were randomly dosed with freshly extracted rumen contents from an adult cow (high efficiency (HE), n = 4), or sterilized rumen content (Con, n = 4). The dosing was administered within 3 days of birth, then at 2, 4, and 6 weeks following the initial dosing. Abomasum tissues were collected immediately after sacrifice at 8 weeks of age. Five genera (Tannerella, Desulfovibrio, Deinococcus, Leptotrichia, and Eubacterium; p < 0.05) showed significant difference in abundance between the treatments. A total of 975 differentially expressed genes were identified (p < 0.05, fold-change > 1.5, mean read-counts > 5). Pathway analysis indicated that up-regulated genes were involved in immune system process and defense response to virus, while the down-regulated genes involved in ion transport, ATP biosynthetic process, and mitochondrial electron transport. Positive correlation (r > 0.7, p < 0.05) was observed between TRPM4 gene and Desulfovibrio, which was significantly higher in the HE group. TRPM4 had a reported role in the immune system process. In conclusion, the dosing of adult rumen contents to calves can alter not only the composition of active microorganisms in the abomasum but also the molecular mechanisms in the abomasum tissue, including reduced protease secretion and decreased hydrochloric acid secretion.
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Affiliation(s)
- Naren Gaowa
- State Key Laboratory of Animal Nutrition, Beijing Engineering Technology, Research Center of Raw Milk Quality and Safety Control, College of Animal Science and Technology, China Agricultural University, No.2 Yuanmingyuan West Road, Haidian, Beijing 100193, China;
| | - Wenli Li
- The Cell Wall Utilization and Biology Laboratory, USDA Agricultural Research Service, US Dairy Forage Research Center, Madison, WI 53706, USA;
| | - Brianna Murphy
- The Cell Wall Utilization and Biology Laboratory, USDA Agricultural Research Service, US Dairy Forage Research Center, Madison, WI 53706, USA;
| | - Madison S. Cox
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA;
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI 53706, USA
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6
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Physiological Significance of Ion Transporters and Channels in the Stomach and Pathophysiological Relevance in Gastric Cancer. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2020; 2020:2869138. [PMID: 32104192 PMCID: PMC7040404 DOI: 10.1155/2020/2869138] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 12/17/2019] [Accepted: 01/08/2020] [Indexed: 12/26/2022]
Abstract
Gastric cancer (GC) is a highly invasive and fatal malignant disease that accounts for 5.7% of new global cancer cases and is the third leading cause of cancer-related death. Acid/base homeostasis is critical for organisms because protein and enzyme function, cellular structure, and plasma membrane permeability change with pH. Various ion transporters are expressed in normal gastric mucosal epithelial cells and regulate gastric acid secretion, ion transport, and fluid absorption, thereby stabilizing the differentiation and homeostasis of gastric mucosal epithelial cells. Ion transporter dysfunction results in disordered ion transport, mucosa barrier dysfunction, and acid/base disturbances, causing gastric acid-related diseases such as chronic atrophic gastritis (CAG) and GC. This review summarizes the physiological functions of multiple ion transporters and channels in the stomach, including Cl− channels, Cl−/HCO3− exchangers, sodium/hydrogen exchangers (NHEs), and potassium (K+) channels, and their pathophysiological relevance in GC.
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7
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Zhang F, Wan H, Yang X, He J, Lu C, Yang S, Tuo B, Dong H. Molecular mechanisms of caffeine-mediated intestinal epithelial ion transports. Br J Pharmacol 2019; 176:1700-1716. [PMID: 30808064 DOI: 10.1111/bph.14640] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 01/10/2019] [Accepted: 01/31/2019] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND AND PURPOSE As little is known about the effect of caffeine, one of the most widely consumed substances worldwide, on intestinal function, we aimed to study its action on intestinal anion secretion and the underlying molecular mechanisms. EXPERIMENTAL APPROACH Anion secretion and channel expression were examined in mouse duodenal epithelium by Ussing chambers and immunocytochemistry. Ca2+ imaging was also performed in intestinal epithelial cells (IECs). KEY RESULTS Caffeine (10 mM) markedly increased mouse duodenal short-circuit current (Isc ), which was attenuated by a removal of either Cl- or HCO3 - , Ca2+ -free serosal solutions and selective blockers of store-operated Ca2+ channels (SOC/Ca2+ release-activated Ca2+ channels), and knockdown of Orai1 channels on the serosal side of duodenal tissues. Caffeine induced SOC entry in IEC, which was inhibited by ruthenium red and selective blockers of SOC. Caffeine-stimulated duodenal Isc was inhibited by the endoplasmic reticulum Ca2+ chelator (N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine), selective blockers (ruthenium red and dantrolene) of ryanodine receptors (RyR), and of Ca2+ -activated Cl- channels (niflumic acid and T16A). There was synergism between cAMP and Ca2+ signalling, in which cAMP/PKA promoted caffeine/Ca2+ -mediated anion secretion. Expression of STIM1 and Orai1 was detected in mouse duodenal mucosa and human IECs. The Orai1 proteins were primarily co-located with the basolateral marker Na+ , K+ -ATPase. CONCLUSIONS AND IMPLICATIONS Caffeine stimulated intestinal anion secretion mainly through the RyR/Orai1/Ca2+ signalling pathway. There is synergism between cAMP/PKA and caffeine/Ca2+ -mediated anion secretion. Our findings suggest that a caffeine-mediated RyR/Orai1/Ca2+ pathway could provide novel potential drug targets to control intestinal anion secretion.
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Affiliation(s)
- Fenglian Zhang
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Hanxing Wan
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Xin Yang
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Jialin He
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Cheng Lu
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Shiming Yang
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Biguang Tuo
- Department of Gastroenterology, Affiliated Hospital, Zunyi Medical College, and Digestive Disease Institute of Guizhou Province, Zunyi, China
| | - Hui Dong
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China.,Department of Medicine, School of Medicine, University of California, San Diego, California, USA
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8
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Li T, Liu X, Riederer B, Nikolovska K, Singh AK, Mäkelä KA, Seidler A, Liu Y, Gros G, Bartels H, Herzig KH, Seidler U. Genetic ablation of carbonic anhydrase IX disrupts gastric barrier function via claudin-18 downregulation and acid backflux. Acta Physiol (Oxf) 2018; 222:e12923. [PMID: 28748627 PMCID: PMC5901031 DOI: 10.1111/apha.12923] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Revised: 11/21/2016] [Accepted: 07/24/2017] [Indexed: 12/28/2022]
Abstract
Aim This study aimed to explore the molecular mechanisms for the parietal cell loss and fundic hyperplasia observed in gastric mucosa of mice lacking the carbonic anhydrase 9 (CAIX). Methods We assessed the ability of CAIX‐knockout and WT gastric surface epithelial cells to withstand a luminal acid load by measuring the pHi of exteriorized gastric mucosa in vivo using two‐photon confocal laser scanning microscopy. Cytokines and claudin‐18A2 expression was analysed by RT‐PCR. Results CAIX‐knockout gastric surface epithelial cells showed significantly faster pHi decline after luminal acid load compared to WT. Increased gastric mucosal IL‐1β and iNOS, but decreased claudin‐18A2 expression (which confer acid resistance) was observed shortly after weaning, prior to the loss of parietal and chief cells. At birth, neither inflammatory cytokines nor claudin‐18 expression were altered between CAIX and WT gastric mucosa. The gradual loss of acid secretory capacity was paralleled by an increase in serum gastrin, IL‐11 and foveolar hyperplasia. Mild chronic proton pump inhibition from the time of weaning did not prevent the claudin‐18 decrease nor the increase in inflammatory markers at 1 month of age, except for IL‐1β. However, the treatment reduced the parietal cell loss in CAIX‐KO mice in the subsequent months. Conclusions We propose that CAIX converts protons that either backflux or are extruded from the cells rapidly to CO2 and H2O, contributing to tight junction protection and gastric epithelial pHi regulation. Lack of CAIX results in persistent acid backflux via claudin‐18 downregulation, causing loss of parietal cells, hypergastrinaemia and foveolar hyperplasia.
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Affiliation(s)
- T. Li
- Department of Gastroenterology; Hannover Medical School; Hannover Germany
| | - X. Liu
- Department of Gastroenterology; Hannover Medical School; Hannover Germany
- Department of Department of Gastroenterology; Affiliated Hospital of Zunyi Medical College; Zunyi China
| | - B. Riederer
- Department of Gastroenterology; Hannover Medical School; Hannover Germany
| | - K. Nikolovska
- Department of Gastroenterology; Hannover Medical School; Hannover Germany
| | - A. K. Singh
- Department of Gastroenterology; Hannover Medical School; Hannover Germany
| | - K. A. Mäkelä
- Institute of Biomedicine and Biocenter of Oulu; Oulu University; Finland
| | - A. Seidler
- Department of Gastroenterology; Hannover Medical School; Hannover Germany
| | - Y. Liu
- Department of Gastroenterology; Hannover Medical School; Hannover Germany
| | - G. Gros
- Department of Physiology; Hannover Medical School; Hannover Germany
| | - H. Bartels
- Department of Anatomy; Hannover Medical School; Hannover Germany
| | - K. H. Herzig
- Institute of Biomedicine and Biocenter of Oulu; Oulu University; Finland
| | - U. Seidler
- Department of Gastroenterology; Hannover Medical School; Hannover Germany
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9
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Development and Characterization of a Human and Mouse Intestinal Epithelial Cell Monolayer Platform. Stem Cell Reports 2017; 9:1976-1990. [PMID: 29153987 PMCID: PMC5785676 DOI: 10.1016/j.stemcr.2017.10.013] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 10/13/2017] [Accepted: 10/15/2017] [Indexed: 12/13/2022] Open
Abstract
We describe the development and characterization of a mouse and human epithelial cell monolayer platform of the small and large intestines, with a broad range of potential applications including the discovery and development of minimally systemic drug candidates. Culture conditions for each intestinal segment were optimized by correlating monolayer global gene expression with the corresponding tissue segment. The monolayers polarized, formed tight junctions, and contained a diversity of intestinal epithelial cell lineages. Ion transport phenotypes of monolayers from the proximal and distal colon and small intestine matched the known and unique physiology of these intestinal segments. The cultures secreted serotonin, GLP-1, and FGF19 and upregulated the epithelial sodium channel in response to known biologically active agents, suggesting intact secretory and absorptive functions. A screen of over 2,000 pharmacologically active compounds for inhibition of potassium ion transport in the mouse distal colon cultures led to the identification of a tool compound. Epithelial cell monolayer growth conditions developed for all intestinal segments Monolayer gene expression is consistent with tissue from each intestinal segment Ion transport, secretory, and absorptive functions match intestinal physiology Compound screen identified inhibitor of mouse distal colon potassium transport
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10
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Paehler Vor der Nolte A, Chodisetti G, Yuan Z, Busch F, Riederer B, Luo M, Yu Y, Menon MB, Schneider A, Stripecke R, Nikolovska K, Yeruva S, Seidler U. Na + /H + exchanger NHE1 and NHE2 have opposite effects on migration velocity in rat gastric surface cells. J Cell Physiol 2017; 232:1669-1680. [PMID: 28019659 PMCID: PMC5396337 DOI: 10.1002/jcp.25758] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 12/21/2016] [Accepted: 12/22/2016] [Indexed: 12/13/2022]
Abstract
Following superficial injury, neighbouring gastric epithelial cells close the wound by rapid cell migration, a process called epithelial restitution. Na+/H+ exchange (NHE) inhibitors interfere with restitution, but the role of the different NHE isoforms expressed in gastric pit cells has remained elusive. The role of the basolaterally expressed NHE1 (Slc9a1) and the presumably apically expressed NHE2 (Slc9a2) in epithelial restitution was investigated in the nontransformed rat gastric surface cell line RGM1. Migration velocity was assessed by loading the cells with the fluorescent dye DiR and following closure of an experimental wound over time. Since RGM1 cells expressed very low NHE2 mRNA and have low transport activity, NHE2 was introduced by lentiviral gene transfer. In medium with pH 7.4, RGM1 cells displayed slow wound healing even in the absence of growth factors and independently of NHE activity. Growth factors accelerated wound healing in a partly NHE1‐dependent fashion. Preincubation with acidic pH 7.1 stimulated restitution in a NHE1‐dependent fashion. When pH 7.1 was maintained during the restitution period, migratory speed was reduced to ∼10% of the speed at pH 7,4, and the residual restitution was further inhibited by NHE1 inhibition. Lentiviral NHE2 expression increased the steady‐state pHi and reduced the restitution velocity after low pH preincubation, which was reversible by pharmacological NHE2 inhibition. The results demonstrate that in RGM1 cells, migratory velocity is increased by NHE1 activation, while NHE2 activity inhibit this process. A differential activation of NHE1 and NHE2 may therefore, play a role in the initiation and completion of the epithelial restitution process.
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Affiliation(s)
- Anja Paehler Vor der Nolte
- Departments of Gastroenterology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Giriprakash Chodisetti
- Departments of Gastroenterology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Zhenglin Yuan
- Departments of Gastroenterology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Florian Busch
- Departments of Gastroenterology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Brigitte Riederer
- Departments of Gastroenterology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Min Luo
- Departments of Gastroenterology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Yan Yu
- Departments of Gastroenterology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Manoj B Menon
- Departments of Biochemistry, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Andreas Schneider
- Departments of Hematology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Renata Stripecke
- Departments of Hematology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Katerina Nikolovska
- Departments of Gastroenterology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Sunil Yeruva
- Departments of Gastroenterology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Ursula Seidler
- Departments of Gastroenterology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
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11
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Yu Q, Liu X, Liu Y, Riederer B, Li T, Tian DA, Tuo B, Shull G, Seidler U. Defective small intestinal anion secretion, dipeptide absorption, and intestinal failure in suckling NBCe1-deficient mice. Pflugers Arch 2016; 468:1419-32. [PMID: 27228994 PMCID: PMC4951514 DOI: 10.1007/s00424-016-1836-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 05/05/2016] [Accepted: 05/09/2016] [Indexed: 11/27/2022]
Abstract
The electrogenic Na+HCO3− cotransporter NBCe1 (Slc4a4) is strongly expressed in the basolateral enterocyte membrane in a villous/surface predominant fashion. In order to better understand its physiological function in the intestine, isolated mucosae in miniaturized Ussing chambers and microdissected intestinal villi or crypts loaded with the fluorescent pH-indicator BCECF were studied from the duodenum, jejunum, and colon of 14- to 17-days-old slc4a4-deficient (KO) and WT mice. NBCe1 was active in the basal state in all intestinal segments under study, most likely to compensate for acid loads imposed upon the enterocytes. Upregulation of other basolateral base uptake mechanism occurs, but in a segment-specific fashion. Loss of NBCe1 resulted in severely impaired Cl− and fluid secretory response, but not HCO3− secretory response to agonist stimulation. In addition, NBCe1 was found to be active during transport processes that load the surface enterocytes with acid, such as Slc26a3 (DRA)-mediated luminal Cl−/HCO3− exchange or PEPT1-mediated H+/dipeptide uptake. Possibly because of the high energy demand for hyperventilation in conjunction with the fluid secretory and nutrient absorptive defects and the relative scarcity of compensatory mechanisms, NBCe1-deficient mice developed progressive jejunal failure, worsening of metabolic acidosis, and death in the third week of life. Our data suggest that the electrogenic influx of base via NBCe1 maintains enterocyte anion homeostasis and pHi control. Its loss impairs small intestinal Cl− and fluid secretion as well as the neutralization of acid loads imposed on the enterocytes during nutrient and electrolyte absorption.
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Affiliation(s)
- Qin Yu
- Department of Gastroenterology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.,Department of Gastroenterology, Tongji Hospital, Huazhong University of Science & Technology, Wuhan, People's Republic of China
| | - Xuemei Liu
- Department of Gastroenterology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.,Department of Gastroenterology, Zunyi Medical College, Zunyi, China
| | - Yongjian Liu
- Department of Gastroenterology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Brigitte Riederer
- Department of Gastroenterology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Taolang Li
- Department of Gastroenterology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.,Department of Gastrointestinal Surgery, Zunyi Medical College, Zunyi, China
| | - De-An Tian
- Department of Gastroenterology, Tongji Hospital, Huazhong University of Science & Technology, Wuhan, People's Republic of China
| | - Biguang Tuo
- Department of Gastroenterology, Zunyi Medical College, Zunyi, China
| | - Gary Shull
- Department of of Molecular Genetics, University of Cincinnati, Cincinnati, OH, USA
| | - Ursula Seidler
- Department of Gastroenterology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
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Ward JBJ, Keely SJ, Keely SJ. Oxygen in the regulation of intestinal epithelial transport. J Physiol 2014; 592:2473-89. [PMID: 24710059 DOI: 10.1113/jphysiol.2013.270249] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The transport of fluid, nutrients and electrolytes to and from the intestinal lumen is a primary function of epithelial cells. Normally, the intestine absorbs approximately 9 l of fluid and 1 kg of nutrients daily, driven by epithelial transport processes that consume large amounts of cellular energy and O2. The epithelium exists at the interface of the richly vascularised mucosa, and the anoxic luminal environment and this steep O2 gradient play a key role in determining the expression pattern of proteins involved in fluid, nutrient and electrolyte transport. However, the dynamic nature of the splanchnic circulation necessitates that the epithelium can evoke co-ordinated responses to fluctuations in O2 availability, which occur either as a part of the normal digestive process or as a consequence of several pathophysiological conditions. While it is known that hypoxia-responsive signals, such as reactive oxygen species, AMP-activated kinase, hypoxia-inducible factors, and prolyl hydroxylases are all important in regulating epithelial responses to altered O2 supply, our understanding of the molecular mechanisms involved is still limited. Here, we aim to review the current literature regarding the role that O2 plays in regulating intestinal transport processes and to highlight areas of research that still need to be addressed.
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Affiliation(s)
- Joseph B J Ward
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Simon J Keely
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle NSW, Australia
| | - Stephen J Keely
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
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Cholecystokinin but not ghrelin stimulates mucosal bicarbonate secretion in rat duodenum: independence of feeding status and cholinergic stimuli. ACTA ACUST UNITED AC 2013; 183:46-53. [PMID: 23499805 DOI: 10.1016/j.regpep.2013.03.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 02/21/2013] [Accepted: 03/03/2013] [Indexed: 01/10/2023]
Abstract
Cholecystokinin (CCK) is an important regulator of food digestion but its influence on small intestinal secretion has received little attention. We characterized effects of CCK-8, ghrelin and some related peptides on duodenal HCO3(-) secretion in vivo and demonstrated CCK-induced calcium signaling in acutely isolated enterocytes. A segment of proximal duodenum with intact blood supply was cannulated in situ in anaesthetized rats. Mucosal HCO3(-) secretion was continuously recorded (pH-stat). Peptides were administrated to the duodenum by close intra-arterial infusion. Clusters of duodenal enterocytes were attached to the bottom of a perfusion chamber. The intracellular calcium concentration ([Ca(2+)]i) was examined by dual-wavelength imaging. CCK-8 (3.0, 15 and 60 pmol/kg,h) caused dose-dependent increases (p<0.01) in duodenal alkaline secretion in both overnight fasted and continuously fed animals. The CCK1R-antagonist devazepide but neither the CCK2R-antagonist YMM022 nor the melatonin MT2-selective antagonist luzindole inhibited the rise in secretion. Atropine decreased sensitivity to CCK-8. The appetite-related peptide ghrelin was without effect on the duodenal secretion in fasted as well as fed animals. Superfusion with CCK-8 (1.0-50 nM) induced [Ca(2+)]i signaling in acutely isolated duodenal enterocytes. After an initial peak response, [Ca(2+)]i returned to near basal values within 3-5min. Devazepide but not YMM022 inhibited this [Ca(2+)]i response. Low doses of CCK-8 stimulate duodenal alkaline secretion and induce enterocyte [Ca(2+)]i signaling by an action at CCK1 receptors. The results point to importance of CCK in the rapid postprandial rise in mucosa-protective duodenal secretion.
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Chen M, Praetorius J, Zheng W, Xiao F, Riederer B, Singh AK, Stieger N, Wang J, Shull GE, Aalkjaer C, Seidler U. The electroneutral Na⁺:HCO₃⁻ cotransporter NBCn1 is a major pHi regulator in murine duodenum. J Physiol 2012; 590:3317-33. [PMID: 22586225 DOI: 10.1113/jphysiol.2011.226506] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Duodenocyte pHi control and HCO3 − secretion protects the proximal duodenum against damage by gastric acid. The molecular details of duodenocyte pH control are not well understood. A selective duodenal expression (within the upper GI tract) has been reported for the electroneutral Na+:HCO3 − cotransporter NBCn1 (Slc4a7). We aimed to determine the role of NBCn1 and NBCe2 in duodenocyte intracellular pH regulation as well as basal and agonist-stimulated duodenal bicarbonate secretion (JHCO3 −), exploiting mouse models of genetic slc4a7 and slc4a5 disruption. Basal and forskolin (FSK)-stimulated JHCO3 − was measured by single-pass perfusion in the duodenum of slc4a7−/− and slc4a7+/+ as well as slc4a5−/− and slc4a5+/+ mice in vivo, and by pH-stat titration in isolated duodenal mucosa in vitro. Duodenocyte HCO3 − uptake rates were fluorometrically assessed after acidification of intact villi and of isolated duodenocytes. Slc4a7−/− mice displayed significantly lower basal and FSK-stimulated duodenal HCO3 − secretion than slc4a7+/+ littermates in vivo. FSK-stimulated HCO3 − secretion was significantly reduced in slc4a7−/− isolated duodenal mucosa. Na+- and HCO3 −-dependent base uptake rates were significantly decreased in slc4a7−/− compared with slc4a7+/+ villus duodenocytes when measured in intact villi. Carbonic anhydrase (CA)-mediated CO2 hydration played no apparent role as a HCO3 − supply mechanism for basal or FSK-stimulated secretion in the slc4a7+/+ duodenum, but was an important alternative HCO3 − supply mechanism in the slc4a7−/− duodenum. NBCe2 (Slc4a5) displayed markedly lower duodenal mRNA expression levels, and its disruption did not interfere with duodenal HCO3 − secretion. The electroneutral Na+:HCO3 − cotransporter NBCn1 (slc4a7) is a major duodenal HCO3 − importer that supplies HCO3 − during basal and FSK-stimulated HCO3 − secretion.
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Affiliation(s)
- Mingmin Chen
- Department of Gastroenterology, Hannover Medical School, Carl-Neuberg-Straße 1, Hannover, D-30625, Germany
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Charoenphandhu N, Laohapitakworn S, Kraidith K, Nakkrasae LI, Jongwattanapisan P, Tharabenjasin P, Krishnamra N. Electrogenic Na+/HCO3- co-transporter-1 is essential for the parathyroid hormone-stimulated intestinal HCO3- secretion. Biochem Biophys Res Commun 2011; 409:775-9. [DOI: 10.1016/j.bbrc.2011.05.087] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 05/14/2011] [Indexed: 01/26/2023]
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