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Chen L, Yi H, Li Q, Duan T, Liu X, Li L, Wang HY, Xing C, Wang RF. T-bet Regulates Ion Channels and Transporters and Induces Apoptosis in Intestinal Epithelial Cells. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2401654. [PMID: 38650111 DOI: 10.1002/advs.202401654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 03/22/2024] [Indexed: 04/25/2024]
Abstract
T-bet, encoded by TBX21, is extensively expressed across various immune cell types, and orchestrates critical functions in their development, survival, and physiological activities. However, the role of T-bet in non-immune compartments, notably the epithelial cells, remains obscure. Herein, a Tet-O-T-bet transgenic mouse strain is generated for doxycycline-inducible T-bet expression in adult animals. Unexpectedly, ubiquitous T-bet overexpression causes acute diarrhea, intestinal damage, and rapid mortality. Cell-type-specific analyses reveal that T-bet-driven pathology is not attributable to its overexpression in CD4+ T cells or myeloid lineages. Instead, inducible T-bet overexpression in the intestinal epithelial cells is the critical determinant of the observed lethal phenotype. Mechanistically, T-bet overexpression modulates ion channel and transporter profiles in gut epithelial cells, triggering profound fluid secretion and subsequent lethal dehydration. Furthermore, ectopic T-bet expression enhances gut epithelial cell apoptosis and markedly suppresses colon cancer development in xenograft models. Collectively, the findings unveil a previously unrecognized role of T-bet in intestinal epithelial cells for inducing apoptosis, diarrhea, and local inflammation, thus implicating its potential as a therapeutic target for the treatment of cancer and inflammatory diseases.
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Affiliation(s)
- Lang Chen
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX, 77030, USA
- Department of General Surgery, Third Xiangya Hospital, Xiangya School of Medicine, Central South University, Changsha, 410013, China
| | - Hongwei Yi
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX, 77030, USA
- Department of Pharmacology, School of Medicine, Southeast University, Nanjing, 210009, China
| | - Qingtian Li
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX, 77030, USA
- Department of Medicine, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Tianhao Duan
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX, 77030, USA
- Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Xin Liu
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX, 77030, USA
- Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Linfeng Li
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX, 77030, USA
- Department of Thoracic Surgery, Xiangya Hospital, Central South University, Changsha, 410008, China
| | - Helen Y Wang
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX, 77030, USA
- Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Changsheng Xing
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX, 77030, USA
- Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Rong-Fu Wang
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX, 77030, USA
- Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
- Department of Pediatrics, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90027, USA
- Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
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Mohamed ME, El-Shafae AM, Fikry E, Elbaramawi SS, Elbatreek MH, Tawfeek N. Casuarina glauca branchlets' extract as a potential treatment for ulcerative colitis: chemical composition, in silico and in vivo studies. Front Pharmacol 2023; 14:1322181. [PMID: 38196993 PMCID: PMC10774231 DOI: 10.3389/fphar.2023.1322181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 11/20/2023] [Indexed: 01/11/2024] Open
Abstract
Ulcerative colitis (UC) is an inflammatory bowel disease that is often resistant to current treatment options, leading to a need for alternative therapies. Herbal products have shown promise in managing various conditions, including UC. However, the potential of Casuarina glauca branchlets ethanolic extract (CGBRE) in treating UC has not been explored. This study aimed to analyze the chemical composition of CGBRE and evaluate its efficacy in UC treatment through in silico and in vivo experiments. LC-ESI-MS/MS was used to identify 86 compounds in CGBRE, with 21 potential bioactive compounds determined through pharmacokinetic analysis. Network pharmacology analysis revealed 171 potential UC targets for the bioactive compounds, including EGFR, LRRK2, and HSP90 as top targets, which were found to bind to key CGBRE compounds through molecular docking. Molecular docking findings suggested that CGBRE may be effective in the prevention or treatment of ulcerative colitis mediated by these proteins, where key CGBRE compounds exhibited good binding affinities through formation of numerous interactions. In vivo studies in rats with acetic acid-induced UC demonstrated that oral administration of 300 mg/kg CGBRE for 6 days reduced UC symptoms and colonic expression of EGFR, LRRK2, and HSP90. These findings supported the therapeutic potential of CGBRE in UC and suggested the need for further preclinical and clinical investigation.
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Affiliation(s)
- Maged E. Mohamed
- Department of Pharmaceutical Sciences, College of Clinical Pharmacy, King Faisal University, Al-Ahsa, Saudi Arabia
| | - Azza M. El-Shafae
- Department of Pharmacognosy, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
| | - Eman Fikry
- Department of Pharmacognosy, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
| | - Samar S. Elbaramawi
- Department of Medicinal Chemistry, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
| | - Mahmoud H. Elbatreek
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
| | - Nora Tawfeek
- Department of Pharmacognosy, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
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Zhao C, Jiang Y, Yin H, Jin Z, Yuan J, Shang H, Song H. Hericium caput-medusae (Bull.: Fr.) Pers. Fermentation concentrate polysaccharide ameliorate diarrhea in DSS-induced early colitis by modulating ion channel. J Funct Foods 2023. [DOI: 10.1016/j.jff.2022.105390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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Jayawardena D, Priyamvada S, Kageyama T, White Z, Kumar A, Griggs TF, Majumder A, Akram R, Anbazhagan AN, Sano T, Dudeja PK. Loss of SLC26A3 Results in Colonic Mucosal Immune Dysregulation via Epithelial-Immune Cell Crosstalk. Cell Mol Gastroenterol Hepatol 2023; 15:903-919. [PMID: 36535508 PMCID: PMC9971172 DOI: 10.1016/j.jcmgh.2022.12.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 12/09/2022] [Accepted: 12/09/2022] [Indexed: 01/07/2023]
Abstract
BACKGROUND & AIMS Down-regulation of chloride transporter SLC26A3 or down-regulated in adenoma (DRA) in colonocytes has recently been linked to the pathogenesis of ulcerative colitis (UC). Because exaggerated immune responses are one of the hallmarks of UC, these current studies were undertaken to define the mechanisms by which loss of DRA relays signals to immune cells to increase susceptibility to inflammation. METHODS NanoString Immunology Panel, fluorescence assisted cell sorting, immunoblotting, immunofluorescence, and quantitative real-time polymerase chain reaction assays were used in wild-type and DRA knockout (KO) mice. Interleukin (IL)-33 blocking was used to determine specific changes in immune cells and co-housing/broad spectrum antibiotics administration, and ex vivo studies in colonoids were conducted to rule out the involvement of microbiota. Colonoid-derived monolayers from healthy and UC patient biopsies were analyzed for translatability. RESULTS There was a marked induction of Th2 (>2-fold), CD4+ Th2 cells (∼8-fold), RORγt+ Th17, and FOXP3+ regulatory T cells (Tregs). DRA KO colons also exhibited a robust induction of IL-33 (>8-fold). In vivo studies using blocking of IL-33 established that T2 immune dysregulation (alterations in ILC2, Th2, and GATA3+ iTregs) in response to loss of DRA was due to altered epithelial-immune cell crosstalk via IL-33. CONCLUSIONS Loss of DRA in colonocytes triggers the release of IL-33 to drive a type 2 immune response. These observations emphasize the critical importance of DRA in mucosal immune homeostasis and its implications in the pathogenesis of UC.
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Affiliation(s)
- Dulari Jayawardena
- Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Shubha Priyamvada
- Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Takahiro Kageyama
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, Illinois
| | - Zachary White
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, Illinois
| | - Anoop Kumar
- Department of Medicine, University of Illinois at Chicago, Chicago, Illinois; Jesse Brown VA Medical Center, Chicago, Illinois
| | - Theodor F Griggs
- Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Apurba Majumder
- Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Ramsha Akram
- Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | | | - Teruyuki Sano
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, Illinois
| | - Pradeep K Dudeja
- Department of Medicine, University of Illinois at Chicago, Chicago, Illinois; Jesse Brown VA Medical Center, Chicago, Illinois.
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Wedenoja S, Saarikivi A, Mälkönen J, Leskinen S, Lehto M, Adeshara K, Tuokkola J, Nikkonen A, Merras-Salmio L, Höyhtyä M, Hörkkö S, Haaramo A, Salonen A, de Vos WM, Korpela K, Kolho KL. Fecal microbiota in congenital chloride diarrhea and inflammatory bowel disease. PLoS One 2022; 17:e0269561. [PMID: 35679312 PMCID: PMC9182261 DOI: 10.1371/journal.pone.0269561] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 05/24/2022] [Indexed: 11/21/2022] Open
Abstract
Background and aims Subjects with congenital chloride diarrhea (CLD; a defect in solute carrier family 26 member 3 (SLC26A3)) are prone to inflammatory bowel disease (IBD). We investigated fecal microbiota in CLD and CLD-associated IBD. We also tested whether microbiota is modulated by supplementation with the short-chain fatty acid butyrate. Subjects and methods We recruited 30 patients with CLD for an observational 3-week follow-up study. Thereafter, 16 consented to oral butyrate substitution for a 3-week observational period. Fecal samples, collected once a week, were assayed for calprotectin and potential markers of inflammation, and studied by 16S ribosomal ribonucleic acid (rRNA) gene amplicon sequencing and compared to that of 19 healthy controls and 43 controls with Crohn’s disease. Data on intestinal symptoms, diet and quality of life were collected. Results Patients with CLD had increased abundances of Proteobacteria, Veillonella, and Prevotella, and lower abundances of normally dominant taxa Ruminococcaceae and Lachnospiraceae when compared with healthy controls and Crohn´s disease. No major differences in fecal microbiota were found between CLD and CLD-associated IBD (including two with yet untreated IBD). Butyrate was poorly tolerated and showed no major effects on fecal microbiota or biomarkers in CLD. Conclusions Fecal microbiota in CLD is different from that of healthy subjects or Crohn´s disease. Unexpectedly, no changes in the microbiota or fecal markers characterized CLD-associated IBD, an entity with high frequency among patients with CLD.
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Affiliation(s)
- Satu Wedenoja
- Obstetrics and Gynecology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Stem Cells and Metabolism Research Program, University of Helsinki, and Folkhälsan Research Center, Helsinki, Finland
| | - Aki Saarikivi
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Jani Mälkönen
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Saara Leskinen
- Department of Pediatrics, University of Kuopio and Kuopio University Hospital, Kuopio, Finland
| | - Markku Lehto
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, Helsinki, Finland
- Abdominal Center, Nephrology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Clinical and Molecular Metabolism, Faculty of Medicine Research Programs, University of Helsinki, Helsinki, Finland
| | - Krishna Adeshara
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, Helsinki, Finland
- Abdominal Center, Nephrology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Clinical and Molecular Metabolism, Faculty of Medicine Research Programs, University of Helsinki, Helsinki, Finland
| | - Jetta Tuokkola
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Anne Nikkonen
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Laura Merras-Salmio
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Miikka Höyhtyä
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Sohvi Hörkkö
- Medical Microbiology and Immunology, Research Unit of Biomedicine, University of Oulu, Oulu, Finland
- Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland
| | - Anu Haaramo
- Department of Otorhinolaryngology, Helsinki University Hospital, Helsinki, Finland
| | - Anne Salonen
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Willem M. de Vos
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Laboratory of Microbiology, Wageningen University, Wageningen, the Netherlands
| | - Katri Korpela
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Kaija-Leena Kolho
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- * E-mail:
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SLC26A9 is selected for endoplasmic reticulum associated degradation (ERAD) via Hsp70-dependent targeting of the soluble STAS domain. Biochem J 2021; 478:4203-4220. [PMID: 34821356 PMCID: PMC8826537 DOI: 10.1042/bcj20210644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 11/23/2021] [Accepted: 11/24/2021] [Indexed: 12/24/2022]
Abstract
SLC26A9, a member of the solute carrier protein family, transports chloride ions across various epithelia. SLC26A9 also associates with other ion channels and transporters linked to human health, and in some cases these heterotypic interactions are essential to support the biogenesis of both proteins. Therefore, understanding how this complex membrane protein is initially folded might provide new therapeutic strategies to overcome deficits in the function of SLC26A9 partners, one of which is associated with Cystic Fibrosis. To this end, we developed a novel yeast expression system for SLC26A9. This facile system has been used extensively with other ion channels and transporters to screen for factors that oversee protein folding checkpoints. As commonly observed for other channels and transporters, we first noted that a substantial fraction of SLC26A9 is targeted for endoplasmic reticulum associated degradation (ERAD), which destroys folding-compromised proteins in the early secretory pathway. We next discovered that ERAD selection requires the Hsp70 chaperone, which can play a vital role in ERAD substrate selection. We then created SLC26A9 mutants and found that the transmembrane-rich domain of SLC26A9 was quite stable, whereas the soluble cytosolic STAS domain was responsible for Hsp70-dependent ERAD. To support data obtained in the yeast model, we were able to recapitulate Hsp70-facilitated ERAD of the STAS domain in human tissue culture cells. These results indicate that a critical barrier to nascent membrane protein folding can reside within a specific soluble domain, one that is monitored by components associated with the ERAD machinery.
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ABCC7/CFTR Expression Is Associated with the Clinical Course of Ulcerative Colitis Patients. Gastroenterol Res Pract 2021; 2021:5536563. [PMID: 34512749 PMCID: PMC8426104 DOI: 10.1155/2021/5536563] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 07/01/2021] [Accepted: 08/17/2021] [Indexed: 12/28/2022] Open
Abstract
Inflammatory bowel disease includes ulcerative colitis (UC) and Crohn's disease (CD) of unknown etiology. The expression of ATP-binding cassette (ABC) family proteins has been associated with drug resistance and development of UC. The cystic fibrosis transmembrane conductance regulator (CFTR) or also known as ABCC7 is involved in the inflammatory chronic response. The aim of this study was to evaluate the role of ABCC7/CFTR in UC patients and normal controls without inflammation. This is an exploratory, observational, and cross-sectional study that included a total of 62 patients with UC and normal controls. Gene expression of CFTR was measured by RT-PCR, and protein expression of CFTR was determined by western blot analysis. We found a significant downregulation of the CFTR gene expression in patients with active UC compared to normal controls without inflammation (P < 0.004); even the gene expression of CFTR was decreased in remission UC patients compared to normal controls without inflammation (P = 0.04). The CFTR gene expression was associated with the clinical course of UC and the protein expression of CFTR was decreased in active UC patients compared to normal controls without inflammation suggesting that this molecule might play a role in the inflammation in UC patients.
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Singh V, Johnson K, Yin J, Lee S, Lin R, Yu H, In J, Foulke-Abel J, Zachos NC, Donowitz M, Rong Y. Chronic Inflammation in Ulcerative Colitis Causes Long-Term Changes in Goblet Cell Function. Cell Mol Gastroenterol Hepatol 2021; 13:219-232. [PMID: 34418586 PMCID: PMC8593611 DOI: 10.1016/j.jcmgh.2021.08.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 08/10/2021] [Accepted: 08/11/2021] [Indexed: 12/22/2022]
Abstract
BACKGROUND & AIMS One of the features of ulcerative colitis (UC) is a defect in the protective mucus layer. This has been attributed to a reduced number of goblet cells (GCs). However, it is not known whether abnormal GC mucus secretion also contributes to the reduced mucus layer. Our aims were to investigate whether GC secretion was abnormal in UC and exists as a long-term effect of chronic inflammation. METHODS Colonoids were established from intestinal stem cells of healthy subjects (HS) and patients with UC. Colonoids were maintained as undifferentiated (UD) or induced to differentiate (DF) and studied as three-dimensional or monolayers on Transwell filters. Total RNA was extracted for quantitative real-time polymerase chain reaction analysis. Carbachol and prostaglandin E2 mediated mucin stimulation was examined by MUC2 IF/confocal microscopy and transmission electron microscopy. RESULTS Colonoids from UC patients can be propagated over many passages; however, they exhibit a reduced rate of growth and transepithelial electrical resistance compared with HS. Differentiated UC colonoid monolayers form a thin and non-continuous mucus layer. UC colonoids have increased expression of secretory lineage markers ATOH1 and SPDEF, along with MUC2 positive GCs, but failed to secrete mucin in response to the cholinergic agonist carbachol and prostaglandin E2, which caused increased secretion in HS. Exposure to tumor necrosis factor α (5 days) reduced the number of GCs, with a greater percentage decrease in UC colonoids compared with HS. CONCLUSIONS Chronic inflammation in UC causes long-term changes in GCs, leading to abnormal mucus secretion. This continued defect in GC mucus secretion may contribute to the recurrence in UC.
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Affiliation(s)
- Varsha Singh
- Division of Gastroenterology & Hepatology, Department of Medicine, Baltimore, Maryland.
| | - Kelli Johnson
- Division of Gastroenterology & Hepatology, Department of Medicine, Baltimore, Maryland; Department of Cellular and Molecular Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jianyi Yin
- Division of Gastroenterology & Hepatology, Department of Medicine, Baltimore, Maryland
| | - Sun Lee
- Division of Gastroenterology & Hepatology, Department of Medicine, Baltimore, Maryland
| | - Ruxian Lin
- Division of Gastroenterology & Hepatology, Department of Medicine, Baltimore, Maryland
| | - Huimin Yu
- Division of Gastroenterology & Hepatology, Department of Medicine, Baltimore, Maryland
| | - Julie In
- Division of Gastroenterology & Hepatology, Department of Medicine, Baltimore, Maryland
| | - Jennifer Foulke-Abel
- Division of Gastroenterology & Hepatology, Department of Medicine, Baltimore, Maryland
| | - Nicholas C Zachos
- Division of Gastroenterology & Hepatology, Department of Medicine, Baltimore, Maryland
| | - Mark Donowitz
- Division of Gastroenterology & Hepatology, Department of Medicine, Baltimore, Maryland; Department of Cellular and Molecular Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Yan Rong
- Division of Gastroenterology & Hepatology, Department of Medicine, Baltimore, Maryland
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Yu Q. Slc26a3 (DRA) in the Gut: Expression, Function, Regulation, Role in Infectious Diarrhea and Inflammatory Bowel Disease. Inflamm Bowel Dis 2021; 27:575-584. [PMID: 32989468 DOI: 10.1093/ibd/izaa256] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND The transport of transepithelial Cl- and HCO3- is crucial for the function of the intestinal epithelium and maintains the acid-based homeostasis. Slc26a3 (DRA), as a key chloride-bicarbonate exchanger protein in the intestinal epithelial luminal membrane, participates in the electroneutral NaCl absorption of intestine, together with Na+/H+ exchangers. Increasing recent evidence supports the essential role of decreased DRA function or expression in infectious diarrhea and inflammatory bowel disease (IBD). METHOD In this review, we give an overview of the current knowledge of Slc26a3, including its cloning and expression, function, roles in infectious diarrhea and IBD, and mechanisms of actions. A better understanding of the physiological and pathophysiological relevance of Slc26a3 in infectious diarrhea and IBD may reveal novel targets for future therapy. CONCLUSION Understanding the physiological function, regulatory interactions, and the potential mechanisms of Slc26a3 in the pathophysiology of infectious diarrhea and IBD will define novel therapeutic approaches in future.
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Affiliation(s)
- Qin Yu
- Department of Gastroenterology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan City, China
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Priyamvada S, Anbazhagan AN, Kumar A, Chatterjee I, Borthakur A, Saksena S, Gill RK, Alrefai WA, Dudeja PK. All-trans Retinoic Acid Counteracts Diarrhea and Inhibition of Downregulated in Adenoma Expression in Gut Inflammation. Inflamm Bowel Dis 2020; 26:534-545. [PMID: 31634391 PMCID: PMC7456978 DOI: 10.1093/ibd/izz249] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Indexed: 12/14/2022]
Abstract
BACKGROUND Intestinal epithelial apical membrane Cl-/HCO3- exchanger DRA (downregulated in adenoma, SLC26A3) has emerged as an important therapeutic target for diarrhea, emphasizing the potential therapeutic role of agents that upregulate DRA. All-trans retinoic acid (ATRA), a key vitamin A metabolite, was earlier shown by us to stimulate DRA expression in intestinal epithelial cells. However, its role in modulating DRA in gut inflammation has not been investigated. AIMS Our aim was to analyze the efficacy of ATRA in counteracting inflammation-induced decrease in DRA in vitro and in vivo. METHODS Interferon-γ (IFN-γ)-treated Caco-2 cells and dextran sulfate sodium (DSS)-treated C57BL/6J mice served as in vitro and in vivo models of gut inflammation, respectively. The effect of ATRA on IFN-γ-mediated inhibition of DRA function, expression, and promoter activity were elucidated. In the DSS colitis model, diarrheal phenotype, cytokine response, in vivo imaging, myeloperoxidase activity, and DRA expression were measured in the distal colon. RESULTS All-trans retinoic acid (10 μM, 24 h) abrogated IFN-γ (30 ng/mL, 24 h)-induced decrease in DRA function, expression, and promoter activity in Caco-2 cells. All-trans retinoic acid altered IFN-γ signaling via blocking IFN-γ-induced tyrosine phosphorylation of STAT-1. All-trans retinoic acid cotreatment (1 mg/kg BW, i.p. daily) of DSS-treated mice (3% in drinking water for 7 days) alleviated colitis-associated weight loss, diarrheal phenotype, and induction of IL-1β and CXCL1 and a decrease in DRA mRNA and protein levels in the colon. CONCLUSION Our data showing upregulation of DRA under normal and inflammatory conditions by ATRA demonstrate a novel role of this micronutrient in alleviating IBD-associated diarrhea.
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Affiliation(s)
- Shubha Priyamvada
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Arivarasu N Anbazhagan
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Anoop Kumar
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Ishita Chatterjee
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Alip Borthakur
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Seema Saksena
- Jesse Brown Veterans Affairs Medical Center, Chicago, IL, USA
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Ravinder K Gill
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Waddah A Alrefai
- Jesse Brown Veterans Affairs Medical Center, Chicago, IL, USA
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Pradeep K Dudeja
- Jesse Brown Veterans Affairs Medical Center, Chicago, IL, USA
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
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Adaptation to inflammatory acidity through neutrophil-derived adenosine regulation of SLC26A3. Mucosal Immunol 2020; 13:230-244. [PMID: 31792360 PMCID: PMC7044055 DOI: 10.1038/s41385-019-0237-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 11/07/2019] [Indexed: 02/04/2023]
Abstract
Acute intestinal inflammation includes the early accumulation of neutrophils (PMN). Based on recent evidence that PMN infiltration "imprints" changes in the local tissue environment through local oxygen depletion and the release of adenine nucleotides, we hypothesized that the interaction between transmigrating PMN and intestinal epithelial cells (IECs) results in inflammatory acidification of the tissue. Using newly developed tools, we revealed that active PMN transepithelial migration (TEM) significantly acidifies the local microenvironment, a decrease of nearly 2 pH units. Using unbiased approaches, we sought to define acid-adaptive pathways elicited by PMN TEM. Given the significant amount of adenosine (Ado) generated during PMN TEM, we profiled the influence of Ado on IECs gene expression by microarray and identified the induction of SLC26A3, the major apical Cl-/HCO3- exchanger in IECs. Utilizing loss- and gain-of-function approaches, as well as murine and human colonoids, we demonstrate that Ado-induced SLC26A3 promotes an adaptive IECs phenotype that buffers local pH during active inflammation. Extending these studies, chronic murine colitis models were used to demonstrate that SLC26A3 expression rebounds during chronic DSS-induced inflammation. In conclusion, Ado signaling during PMN TEM induces an adaptive tissue response to inflammatory acidification through the induction of SLC26A3 expression, thereby promoting pH homeostasis.
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Rao MC. Physiology of Electrolyte Transport in the Gut: Implications for Disease. Compr Physiol 2019; 9:947-1023. [PMID: 31187895 DOI: 10.1002/cphy.c180011] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We now have an increased understanding of the genetics, cell biology, and physiology of electrolyte transport processes in the mammalian intestine, due to the availability of sophisticated methodologies ranging from genome wide association studies to CRISPR-CAS technology, stem cell-derived organoids, 3D microscopy, electron cryomicroscopy, single cell RNA sequencing, transgenic methodologies, and tools to manipulate cellular processes at a molecular level. This knowledge has simultaneously underscored the complexity of biological systems and the interdependence of multiple regulatory systems. In addition to the plethora of mammalian neurohumoral factors and their cross talk, advances in pyrosequencing and metagenomic analyses have highlighted the relevance of the microbiome to intestinal regulation. This article provides an overview of our current understanding of electrolyte transport processes in the small and large intestine, their regulation in health and how dysregulation at multiple levels can result in disease. Intestinal electrolyte transport is a balance of ion secretory and ion absorptive processes, all exquisitely dependent on the basolateral Na+ /K+ ATPase; when this balance goes awry, it can result in diarrhea or in constipation. The key transporters involved in secretion are the apical membrane Cl- channels and the basolateral Na+ -K+ -2Cl- cotransporter, NKCC1 and K+ channels. Absorption chiefly involves apical membrane Na+ /H+ exchangers and Cl- /HCO3 - exchangers in the small intestine and proximal colon and Na+ channels in the distal colon. Key examples of our current understanding of infectious, inflammatory, and genetic diarrheal diseases and of constipation are provided. © 2019 American Physiological Society. Compr Physiol 9:947-1023, 2019.
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Affiliation(s)
- Mrinalini C Rao
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois, USA
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13
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Kamal NM, Khan HY, El-Shabrawi MH, Sherief LM. Congenital chloride losing diarrhea: A single center experience in a highly consanguineous population. Medicine (Baltimore) 2019; 98:e15928. [PMID: 31145360 PMCID: PMC6709049 DOI: 10.1097/md.0000000000015928] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Congenital chloride losing diarrhea (CCLD) is a rare type of chronic watery diarrhea due to mutations in SLC26A3 gene leading to defective chloride-bicarbonate exchanges with the resultant loss of chloride and retention of bicarbonate.We aim to define pediatric Saudi CCLD patients' characteristics to achieve prompt diagnosis, management, follow up with good quality of life, and prevention of complications in these patients.We carried retrospective data review of demographic, clinical, laboratory, radiographic, and outcome of all pediatric patients fulfilling the criteria of CCLD over 10 years from 2004 to 2014 from a single center in Taif region, Saudi Arabia.Forty-nine patients fulfilled the criteria of CCLD from 21 families with more than one affected patient in the same family in 90% of them and positive consanguinity in 91% of the cohort. Most patients were born preterm with intrauterine growth restriction and usually neonatal intensive care unit (NICU) admissions with prematurity and its complications. Thirteen patients were discharged without diagnosis of CCLD and 3 were misdiagnosed as intestinal obstruction with unnecessary surgical intervention. Many complications do existed with renal complications being the most common with three patients received renal transplantation.Prematurity with abdominal distension and stool like urine were the commonest presentation of CCLD in Saudi children. Positive consanguinity and more than one affected sibling are present in most of our cohort.High index of suspicion by clinicians is a cornerstone for early diagnosis with subsequent favorable outcome.A multicenter national incidence study of CCLD in KSA and its genetic attributes is recommended. Premarital screening should be implemented specially for consanguineous marriage.
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Affiliation(s)
- Naglaa M. Kamal
- Pediatrics and Pediatric Hepatology, Faculty of Medicine, Cairo University, Egypt
- Pediatric Hepatology and Gastroenterology, Alhada Armed Forces Hospital, Taif, KSA
| | | | | | - Laila M. Sherief
- Pediatrics and Pediatric Hematology, Faculty of Medicine, Zagazig University, Egypt
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Seidler U, Nikolovska K. Slc26 Family of Anion Transporters in the Gastrointestinal Tract: Expression, Function, Regulation, and Role in Disease. Compr Physiol 2019; 9:839-872. [DOI: 10.1002/cphy.c180027] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Kittayaruksakul S, Sawasvirojwong S, Noitem R, Pongkorpsakol P, Muanprasat C, Chatsudthipong V. Activation of constitutive androstane receptor inhibits intestinal CFTR-mediated chloride transport. Biomed Pharmacother 2019; 111:1249-1259. [PMID: 30841439 DOI: 10.1016/j.biopha.2019.01.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 01/04/2019] [Accepted: 01/06/2019] [Indexed: 11/18/2022] Open
Abstract
Constitutive androstane receptor (CAR) belonging to the nuclear receptor superfamily plays an important role in the xenobiotic metabolism and disposition. It has been reported that CAR regulates the expression of the ATP-binding cassette (ABC) transporters in the intestine, such as multidrug resistance protein 1 (MDR1) and multidrug resistance-associated protein 2/3 (MRP2 and MRP3). In this study, we investigated the role of CAR in the regulation of cystic fibrosis transmembrane conductance regulator (CFTR)-mediated chloride transport in T84 human colonic epithelial cells and mouse intestinal tissues. Treatments of T84 cell monolayers with specific CAR agonists (CITCO and phenytoin at concentrations of 1 μM and 5 μM, respectively) for 24 h decreased transepithelial Cl- secretion in response to cAMP-dependent agonist. This inhibition was abolished by coincubation of CITCO with a CAR antagonist, CINPA1. We confirmed that an inhibitory effect of CAR agonists was not due to their cytotoxicity. Basolateral membrane permeabilization experiments also revealed that activation of CAR decreased apical Cl- current stimulated by both CPT-cAMP and genistein (a direct CFTR activator). Such activation also reduced both mRNA and protein expression of CFTR. Furthermore, CITCO decreased cholera toxin (CT)-induced Cl- secretion across T84 cell monolayers. In ICR mice, administration of TCPOBOP (3 mg/kgBW), a murine-specific CAR agonist, for 7 days produced significant decreases in CFTR mRNA and protein expressions in intestinal tissues. Interestingly, TCPOBOP also inhibited CT-induced intestinal fluid accumulation in mice. This is the first evidence showing that CFTR was downregulated by CAR activation in the intestine. Our findings suggest that CAR has potential as a new drug target for treatment of condition with hyperactivity/ hyperfunction of CFTR especially secretory diarrheas.
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Affiliation(s)
- Suticha Kittayaruksakul
- Department of Basic Medical Science, Faculty of Medicine Vajira Hospital, Navamindradhiraj University, Bangkok, Thailand
| | - Sutthipong Sawasvirojwong
- Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Samut Prakan, Thailand
| | - Rattikarn Noitem
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Pawin Pongkorpsakol
- Translational Medicine Graduate Program, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Chatchai Muanprasat
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand; Excellent Center for Drug Discovery, Thailand Center of Excellence for Life Sciences (TCELS), Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Varanuj Chatsudthipong
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand; Research Center of Transport Protein for Medical Innovation, Faculty of Science, Mahidol University, Bangkok, Thailand.
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Lenzen H, Qian J, Manns MP, Seidler U, Jörns A. Restoration of mucosal integrity and epithelial transport function by concomitant anti-TNFα treatment in chronic DSS-induced colitis. J Mol Med (Berl) 2018; 96:831-843. [DOI: 10.1007/s00109-018-1658-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 05/27/2018] [Accepted: 06/01/2018] [Indexed: 12/25/2022]
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Abstract
Inflammatory bowel diseases broadly categorized into Crohn's disease (CD) and ulcerative colitis (UC), are chronic inflammatory disorders of the gastrointestinal tract with increasing prevalence worldwide. The etiology of the disease is complex and involves a combination of genetic, environmental, immunological and gut microbial factors. Recurring and bloody diarrhea is the most prevalent and debilitating symptom in IBD. The pathogenesis of IBD-associated diarrhea is multifactorial and is essentially an outcome of mucosal damage caused by persistent inflammation resulting in dysregulated intestinal ion transport, impaired epithelial barrier function and increased accessibility of the pathogens to the intestinal mucosa. Altered expression and/or function of epithelial ion transporters and channels is the principle cause of electrolyte retention and water accumulation in the intestinal lumen leading to diarrhea in IBD. Aberrant barrier function further contributes to diarrhea via leak-flux mechanism. Mucosal penetration of enteric pathogens promotes dysbiosis and exacerbates the underlying immune system further perpetuating IBD associated-tissue damage and diarrhea. Here, we review the mechanisms of impaired ion transport and loss of epithelial barrier function contributing to diarrhea associated with IBD.
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Affiliation(s)
- Arivarasu N Anbazhagan
- a Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago , IL , USA
| | - Shubha Priyamvada
- a Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago , IL , USA
| | - Waddah A Alrefai
- a Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago , IL , USA.,b Jesse Brown VA Medical Center , Chicago , IL , USA
| | - Pradeep K Dudeja
- a Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago , IL , USA.,b Jesse Brown VA Medical Center , Chicago , IL , USA
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Kc R, Shukla SD, Walters EH, O'Toole RF. Temporal upregulation of host surface receptors provides a window of opportunity for bacterial adhesion and disease. MICROBIOLOGY-SGM 2017; 163:421-430. [PMID: 28113047 DOI: 10.1099/mic.0.000434] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Host surface receptors provide bacteria with a foothold from which to attach, colonize and, in some cases, invade tissue and elicit human disease. In this review, we discuss several key host receptors and cognate adhesins that function in bacterial pathogenesis. In particular, we examine the elevated expression of host surface receptors such as CEACAM-1, CEACAM-6, ICAM-1 and PAFR in response to specific stimuli. We explore how upregulated receptors, in turn, expose the host to a range of bacterial infections in the respiratory tract. It is apparent that exploitation of receptor induction for bacterial adherence is not unique to one body system, but is also observed in the central nervous, gastrointestinal and urogenital systems. Prokaryotic pathogens which utilize this mechanism for their infectivity include Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis and Escherichia coli. A number of approaches have been used, in both in vitro and in vivo experimental models, to inhibit bacterial attachment to temporally expressed host receptors. Some of these novel strategies may advance future targeted interventions for the prevention and treatment of bacterial disease.
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Affiliation(s)
- Rajendra Kc
- School of Medicine, Faculty of Health, University of Tasmania, Hobart, TAS 7000, Australia
| | - Shakti D Shukla
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, The University of Newcastle, Newcastle, NSW 2308, Australia.,Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute, New Lambton Heights, Newcastle, NSW 2305, Australia
| | - Eugene H Walters
- School of Medicine, Faculty of Health, University of Tasmania, Hobart, TAS 7000, Australia
| | - Ronan F O'Toole
- School of Medicine, Faculty of Health, University of Tasmania, Hobart, TAS 7000, Australia
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Anbazhagan AN, Thaqi M, Priyamvada S, Jayawardena D, Kumar A, Gujral T, Chatterjee I, Mugarza E, Saksena S, Onyuksel H, Dudeja PK. GLP-1 nanomedicine alleviates gut inflammation. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2016; 13:659-665. [PMID: 27553076 DOI: 10.1016/j.nano.2016.08.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 07/20/2016] [Accepted: 08/04/2016] [Indexed: 01/15/2023]
Abstract
The gut hormone, glucagon like peptide-1 (GLP-1) exerts anti-inflammatory effects. However, its clinical use is limited by its short half-life. Previously, we have shown that GLP-1 as a nanomedicine (GLP-1 in sterically stabilized phospholipid micelles, GLP-1-SSM) has increased in vivo stability. The current study was aimed at testing the efficacy of this GLP-1 nanomedicine in alleviating colonic inflammation and associated diarrhea in dextran sodium sulfate (DSS) induced mouse colitis model. Our results show that GLP-1-SSM treatment markedly alleviated the colitis phenotype by reducing the expression of pro-inflammatory cytokine IL-1β, increasing goblet cells and preserving intestinal epithelial architecture in colitis model. Further, GLP-1-SSM alleviated diarrhea (as assessed by luminal fluid) by increasing protein expression of intestinal chloride transporter DRA (down regulated in adenoma). Our results indicate that GLP-1 nanomedicine may act as a novel therapeutic tool in alleviating gut inflammation and associated diarrhea in inflammatory bowel disease (IBD).
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Affiliation(s)
- Arivarasu N Anbazhagan
- Department of Medicine, Division of Gastroenterology and Hepatology, College of Medicine, University of Illinois, Chicago, IL, USA
| | - Mentor Thaqi
- Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois, Chicago, IL, USA
| | - Shubha Priyamvada
- Department of Medicine, Division of Gastroenterology and Hepatology, College of Medicine, University of Illinois, Chicago, IL, USA
| | - Dulari Jayawardena
- Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois, Chicago, IL, USA
| | - Anoop Kumar
- Department of Medicine, Division of Gastroenterology and Hepatology, College of Medicine, University of Illinois, Chicago, IL, USA
| | - Tarunmeet Gujral
- Department of Medicine, Division of Gastroenterology and Hepatology, College of Medicine, University of Illinois, Chicago, IL, USA
| | - Ishita Chatterjee
- Department of Medicine, Division of Gastroenterology and Hepatology, College of Medicine, University of Illinois, Chicago, IL, USA
| | - Edurne Mugarza
- Department of Medicine, Division of Gastroenterology and Hepatology, College of Medicine, University of Illinois, Chicago, IL, USA
| | - Seema Saksena
- Department of Medicine, Division of Gastroenterology and Hepatology, College of Medicine, University of Illinois, Chicago, IL, USA
| | - Hayat Onyuksel
- Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois, Chicago, IL, USA
| | - Pradeep K Dudeja
- Department of Medicine, Division of Gastroenterology and Hepatology, College of Medicine, University of Illinois, Chicago, IL, USA; Jesse Brown VA Medical Center, Chicago, IL, USA.
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20
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Magalhães D, Cabral JM, Soares-da-Silva P, Magro F. Role of epithelial ion transports in inflammatory bowel disease. Am J Physiol Gastrointest Liver Physiol 2016; 310:G460-76. [PMID: 26744474 DOI: 10.1152/ajpgi.00369.2015] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 01/02/2016] [Indexed: 02/06/2023]
Abstract
Inflammatory bowel disease (IBD) is a chronic inflammatory disorder with a complex pathogenesis. Diarrhea is a highly prevalent and often debilitating symptom of IBD patients that results, at least in part, from an intestinal hydroelectrolytic imbalance. Evidence suggests that reduced electrolyte absorption is more relevant than increased secretion to this disequilibrium. This systematic review analyses and integrates the current evidence on the roles of epithelial Na(+)-K(+)-ATPase (NKA), Na(+)/H(+) exchangers (NHEs), epithelial Na(+) channels (ENaC), and K(+) channels (KC) in IBD-associated diarrhea. NKA is the key driving force of the transepithelial ionic transport and its activity is decreased in IBD. In addition, the downregulation of apical NHE and ENaC and the upregulation of apical large-conductance KC all contribute to the IBD-associated diarrhea by lowering sodium absorption and/or increasing potassium secretion.
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Affiliation(s)
- Diogo Magalhães
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal; and MedInUP-Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal
| | - José Miguel Cabral
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal; and MedInUP-Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal
| | - Patrício Soares-da-Silva
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal; and MedInUP-Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal
| | - Fernando Magro
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal; and MedInUP-Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal
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21
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Mechanisms Underlying Dysregulation of Electrolyte Absorption in Inflammatory Bowel Disease-Associated Diarrhea. Inflamm Bowel Dis 2015; 21:2926-35. [PMID: 26595422 PMCID: PMC4662046 DOI: 10.1097/mib.0000000000000504] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Inflammatory bowel diseases (IBDs), including Crohn's disease and ulcerative colitis, are chronic relapsing inflammatory disorders of the gastrointestinal tract. Chronic inflammation of the intestine affects the normal fluid and electrolyte absorption leading to diarrhea, the hallmark symptom of IBD. The management of IBD-associated diarrhea still remains to be a challenge, and extensive studies over the last 2 decades have focused on investigating the molecular mechanisms underlying IBD-associated diarrhea. These studies have shown that the predominant mechanism of diarrhea in IBD involves impairment of electroneutral NaCl absorption, with very little role if any played by anion secretion. The electroneutral NaCl absorption involves coupled operation of Na/H exchanger 3 (NHE3 or SLC9A3) and Cl/HCO3 exchanger DRA (Down Regulated in Adenoma, or SLC26A3). Increasing evidence now supports the critical role of a marked decrease in NHE3 and DRA function and/or expression in IBD-associated diarrhea. This review provides a detailed analysis of the current knowledge related to alterations in NHE3 and DRA function and expression in IBD including the mechanisms underlying these observations and highlights the potential of these transporters as important and novel therapeutic targets.
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22
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Arora K, Sinha C, Zhang W, Moon CS, Ren A, Yarlagadda S, Dostmann WR, Adebiyi A, Haberman Y, Denson LA, Wang X, Naren AP. Altered cGMP dynamics at the plasma membrane contribute to diarrhea in ulcerative colitis. THE AMERICAN JOURNAL OF PATHOLOGY 2015; 185:2790-804. [PMID: 26261085 DOI: 10.1016/j.ajpath.2015.06.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 05/31/2015] [Accepted: 06/29/2015] [Indexed: 12/19/2022]
Abstract
Ulcerative colitis (UC) belongs to inflammatory bowel disorders, a group of gastrointestinal disorders that can produce serious recurring diarrhea in affected patients. The mechanism for UC- and inflammatory bowel disorder-associated diarrhea is not well understood. The cystic fibrosis transmembrane-conductance regulator (CFTR) chloride channel plays an important role in fluid and water transport across the intestinal mucosa. CFTR channel function is regulated in a compartmentalized manner through the formation of CFTR-containing macromolecular complexes at the plasma membrane. In this study, we demonstrate the involvement of a novel macromolecular signaling pathway that causes diarrhea in UC. We found that a nitric oxide-producing enzyme, inducible nitric oxide synthase (iNOS), is overexpressed under the plasma membrane and generates compartmentalized cGMP in gut epithelia in UC. The scaffolding protein Na(+)/H(+) exchanger regulatory factor 2 (NHERF2) bridges iNOS with CFTR, forming CFTR-NHERF2-iNOS macromolecular complexes that potentiate CFTR channel function via the nitric oxide-cGMP pathway under inflammatory conditions both in vitro and in vivo. Potential disruption of these complexes in Nherf2(-/-) mice may render them more resistant to CFTR-mediated secretory diarrhea than Nherf2(+/+) mice in murine colitis models. Our study provides insight into the mechanism of pathophysiologic occurrence of diarrhea in UC and suggests that targeting CFTR and CFTR-containing macromolecular complexes will ameliorate diarrheal symptoms and improve conditions associated with inflammatory bowel disorders.
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Affiliation(s)
- Kavisha Arora
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Chandrima Sinha
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Weiqiang Zhang
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee; Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Chang Suk Moon
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Aixia Ren
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Sunitha Yarlagadda
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | | | - Adebowale Adebiyi
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Yael Haberman
- Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Lee A Denson
- Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Xusheng Wang
- Department of Structural Biology and Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Anjaparavanda P Naren
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee.
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Reimold FR, Balasubramanian S, Doroquez DB, Shmukler BE, Zsengeller ZK, Saslowsky D, Thiagarajah JR, Stillman IE, Lencer WI, Wu BL, Villalpando-Carrion S, Alper SL. Congenital chloride-losing diarrhea in a Mexican child with the novel homozygous SLC26A3 mutation G393W. Front Physiol 2015; 6:179. [PMID: 26157392 PMCID: PMC4477073 DOI: 10.3389/fphys.2015.00179] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 05/27/2015] [Indexed: 12/15/2022] Open
Abstract
Congenital chloride diarrhea is an autosomal recessive disease caused by mutations in the intestinal lumenal membrane Cl−/HCO−3 exchanger, SLC26A3. We report here the novel SLC26A3 mutation G393W in a Mexican child, the first such report in a patient from Central America. SLC26A3 G393W expression in Xenopus oocytes exhibits a mild hypomorphic phenotype, with normal surface expression and moderately reduced anion transport function. However, expression of HA-SLC26A3 in HEK-293 cells reveals intracellular retention and greatly decreased steady-state levels of the mutant polypeptide, in contrast to peripheral membrane expression of the wildtype protein. Whereas wildtype HA-SLC26A3 is apically localized in polarized monolayers of filter-grown MDCK cells and Caco2 cells, mutant HA-SLC26A3 G393W exhibits decreased total polypeptide abundance, with reduced or absent surface expression and sparse punctate (or absent) intracellular distribution. The WT protein is similarly localized in LLC-PK1 cells, but the mutant fails to accumulate to detectable levels. We conclude that the chloride-losing diarrhea phenotype associated with homozygous expression of SLC26A3 G393W likely reflects lack of apical surface expression in enterocytes, secondary to combined abnormalities in polypeptide trafficking and stability. Future progress in development of general or target-specific folding chaperonins and correctors may hold promise for pharmacological rescue of this and similar genetic defects in membrane protein targeting.
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Affiliation(s)
- Fabian R Reimold
- Renal Division, Beth Israel Deaconess Medical Center Boston, MA, USA
| | | | - David B Doroquez
- Renal Division, Beth Israel Deaconess Medical Center Boston, MA, USA
| | - Boris E Shmukler
- Renal Division, Beth Israel Deaconess Medical Center Boston, MA, USA
| | - Zsuzsanna K Zsengeller
- Department of Pathology, Beth Israel Deaconess Medical Center Boston, MA, USA ; Department of Pathology, Harvard Medical School Boston, MA, USA
| | - David Saslowsky
- Division of Pediatric Gastroenterology, Boston Children's Hospital Boston, MA, USA ; Department of Pediatrics, Harvard Medical School Boston, MA, USA ; Harvard Digestive Diseases Center, Harvard Medical School Boston, MA, USA
| | - Jay R Thiagarajah
- Division of Pediatric Gastroenterology, Boston Children's Hospital Boston, MA, USA ; Department of Pediatrics, Harvard Medical School Boston, MA, USA ; Harvard Digestive Diseases Center, Harvard Medical School Boston, MA, USA
| | - Isaac E Stillman
- Renal Division, Beth Israel Deaconess Medical Center Boston, MA, USA ; Department of Pathology, Beth Israel Deaconess Medical Center Boston, MA, USA ; Department of Pathology, Harvard Medical School Boston, MA, USA
| | - Wayne I Lencer
- Division of Pediatric Gastroenterology, Boston Children's Hospital Boston, MA, USA ; Department of Pediatrics, Harvard Medical School Boston, MA, USA ; Harvard Digestive Diseases Center, Harvard Medical School Boston, MA, USA
| | - Bai-Lin Wu
- Department of Pathology, Harvard Medical School Boston, MA, USA ; Genetics Diagnostic Laboratory and Claritas Genetics, Boston Children's Hospital Boston, MA, USA ; Children's Hospital and Institute of Biomedical Sciences of Fudan University Shanghai, China
| | - Salvador Villalpando-Carrion
- Department of Pediatric Gastroenterology and Nutrition, Hospital Infantil de Mexico Federico Gomez Mexico City, Mexico
| | - Seth L Alper
- Renal Division, Beth Israel Deaconess Medical Center Boston, MA, USA ; Harvard Digestive Diseases Center, Harvard Medical School Boston, MA, USA ; Department of Medicine, Harvard Medical School Boston, MA, USA
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24
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Yeruva S, Chodisetti G, Luo M, Chen M, Cinar A, Ludolph L, Lünnemann M, Goldstein J, Singh AK, Riederer B, Bachmann O, Bleich A, Gereke M, Bruder D, Hagen S, He P, Yun C, Seidler U. Evidence for a causal link between adaptor protein PDZK1 downregulation and Na⁺/H⁺ exchanger NHE3 dysfunction in human and murine colitis. Pflugers Arch 2014; 467:1795-807. [PMID: 25271043 PMCID: PMC4383727 DOI: 10.1007/s00424-014-1608-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 09/02/2014] [Accepted: 09/03/2014] [Indexed: 12/13/2022]
Abstract
A dysfunction of the Na(+)/H(+) exchanger isoform 3 (NHE3) significantly contributes to the reduced salt absorptive capacity of the inflamed intestine. We previously reported a strong decrease in the NHERF family member PDZK1 (NHERF3), which binds to NHE3 and regulates its function in a mouse model of colitis. The present study investigates whether a causal relationship exists between the decreased PDZK1 expression and the NHE3 dysfunction in human and murine intestinal inflammation. Biopsies from the colon of patients with ulcerative colitis, murine inflamed ileal and colonic mucosa, NHE3-transfected Caco-2BBe colonic cells with short hairpin RNA (shRNA) knockdown of PDZK1, and Pdzk1-gene-deleted mice were studied. PDZK1 mRNA and protein expression was strongly decreased in inflamed human and murine intestinal tissue as compared to inactive disease or control tissue, whereas that of NHE3 or NHERF1 was not. Inflamed human and murine intestinal tissues displayed correct brush border localization of NHE3 but reduced acid-activated NHE3 transport activity. A similar NHE3 transport defect was observed when PDZK1 protein content was decreased by shRNA knockdown in Caco-2BBe cells or when enterocyte PDZK1 protein content was decreased to similar levels as found in inflamed mucosa by heterozygote breeding of Pdzk1-gene-deleted and WT mice. We conclude that a decrease in PDZK1 expression, whether induced by inflammation, shRNA-mediated knockdown, or heterozygous breeding, is associated with a decreased NHE3 transport rate in human and murine enterocytes. We therefore hypothesize that inflammation-induced loss of PDZK1 expression may contribute to the NHE3 dysfunction observed in the inflamed intestine.
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Affiliation(s)
- Sunil Yeruva
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany
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Singh V, Kumar A, Raheja G, Anbazhagan AN, Priyamvada S, Saksena S, Jhandier MN, Gill RK, Alrefai WA, Borthakur A, Dudeja PK. Lactobacillus acidophilus attenuates downregulation of DRA function and expression in inflammatory models. Am J Physiol Gastrointest Liver Physiol 2014; 307:G623-31. [PMID: 25059823 PMCID: PMC4166720 DOI: 10.1152/ajpgi.00104.2014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Probiotics, including Lactobacilli, are commensal bacteria that have been used in clinical trials and experimental models for the prevention and treatment of diarrheal disorders. Our previous studies have shown that Lactobacillus acidophilus (LA) and its culture supernatant (CS) stimulated Cl(-)/HCO3 (-) exchange activity, acutely via an increase in the surface levels of downregulated in adenoma (DRA, SLC26A3) and in long-term treatments via increasing its expression involving transcriptional mechanisms. However, the role of LA in modulating DRA activity under inflammatory conditions is not known. Current in vitro studies using human intestinal epithelial Caco-2 cells examined the efficacy of LA or its CS in counteracting the inhibitory effects of interferon-γ (IFN-γ) on Cl(-)/HCO3 (-) exchange activity. Pretreatment of cells with LA or LA-CS for 1 h followed by coincubation with IFN-γ significantly alleviated the inhibitory effects of IFN-γ on Cl(-)/HCO3 (-) exchange activity. In the in vivo model of dextran sulfate sodium-induced experimental colitis (3% in drinking water for 7 days) in C57BL/6J mice, administration of live LA (3 × 10(9) colony-forming units) via oral gavage attenuated colonic inflammation. LA administration also counteracted the colitis-induced decrease in DRA mRNA and protein levels. Efficacy of LA or its secreted soluble factors in alleviating inflammation and inflammation-associated dysregulation of DRA activity could justify their therapeutic potential in inflammatory diarrheal diseases.
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Affiliation(s)
- Varsha Singh
- 1Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; and
| | - Anoop Kumar
- 1Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; and ,2Singhania University, Pacheri Bari, Rajasthan, India
| | - Geetu Raheja
- 1Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; and
| | - Arivarasu N. Anbazhagan
- 1Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; and
| | - Shubha Priyamvada
- 1Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; and
| | - Seema Saksena
- 1Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; and
| | - Muhammad Nauman Jhandier
- 1Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; and
| | - Ravinder K. Gill
- 1Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; and
| | - Waddah A. Alrefai
- 1Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; and
| | - Alip Borthakur
- 1Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; and
| | - Pradeep K. Dudeja
- 1Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; and
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Patanayindee J, Muanprasat C, Soodvilai S, Chatsudthipong V. Antidiarrheal efficacy of a quinazolin CFTR inhibitor on human intestinal epithelial cell and in mouse model of cholera. Indian J Pharmacol 2013; 44:619-23. [PMID: 23112425 PMCID: PMC3480796 DOI: 10.4103/0253-7613.100392] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2011] [Revised: 05/16/2012] [Accepted: 07/04/2012] [Indexed: 12/26/2022] Open
Abstract
Objective: This study aimed to evaluate the antidiarrheal efficacy and pharmacological properties of ethyl 2-(4-oxo-3-o-tolyl-3,4-dihydroquinazolin-2-ylthio)acetate (DQA) as an inhibitor of cystic fibrosis transmembrane conductance regulator protein (CFTR) both in vitro and in vivo. Materials and Methods: The effects of DQA on CFTR function and cell viability were investigated in Fisher rat thyroid (FRT) cells expressing human CFTR and human intestinal epithelial T84 cells by short-circuit current measurements and MTT assays, respectively. In vivo antidiarrheal efficacy of DQA was evaluated in a closed loop model of cholera in mice. Results: In permeabilized FRT cells, apical chloride current induced by CFTR agonists (10 μM forskolin, 100 μM CPT-cAMP, and 20 μM apigenin) was inhibited by DQA with IC50 ~ 20 μM and complete inhibition at 200 μM. The inhibitory effect was reversible and not associated with cytotoxicity to FRT cells (5–500 μM DQA for 24 h). Likewise, DQA effectively inhibited both forskolin and cholera toxin-induced transepithelial chloride secretion in T84 cells. In mice, intraluminal injection of 100 μM DQA reduced cholera toxin (1 μg/closed loop)-induced intestinal fluid secretion by 85% without affecting intestinal fluid absorption. Conclusions: DQA represents a new class of small molecule CFTR inhibitor with potential application in treatment of cholera.
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Affiliation(s)
- Jenvit Patanayindee
- Department of Physiology and Research Center of Transport Protein for Medical Innovation, Faculty of Science, Mahidol University, Bangkok, Thailand
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27
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Alper SL, Sharma AK. The SLC26 gene family of anion transporters and channels. Mol Aspects Med 2013; 34:494-515. [PMID: 23506885 DOI: 10.1016/j.mam.2012.07.009] [Citation(s) in RCA: 249] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 06/21/2012] [Indexed: 02/08/2023]
Abstract
The phylogenetically ancient SLC26 gene family encodes multifunctional anion exchangers and anion channels transporting a broad range of substrates, including Cl(-), HCO3(-), sulfate, oxalate, I(-), and formate. SLC26 polypeptides are characterized by N-terminal cytoplasmic domains, 10-14 hydrophobic transmembrane spans, and C-terminal cytoplasmic STAS domains, and appear to be homo-oligomeric. SLC26-related SulP proteins of marine bacteria likely transport HCO3(-) as part of oceanic carbon fixation. SulP genes present in antibiotic operons may provide sulfate for antibiotic biosynthetic pathways. SLC26-related Sultr proteins transport sulfate in unicellular eukaryotes and in plants. Mutations in three human SLC26 genes are associated with congenital or early onset Mendelian diseases: chondrodysplasias for SLC26A2, chloride diarrhea for SLC26A3, and deafness with enlargement of the vestibular aqueduct for SLC26A4. Additional disease phenotypes evident only in mouse knockout models include oxalate urolithiasis for Slc26a6 and Slc26a1, non-syndromic deafness for Slc26a5, gastric hypochlorhydria for Slc26a7 and Slc26a9, distal renal tubular acidosis for Slc26a7, and male infertility for Slc26a8. STAS domains are required for cell surface expression of SLC26 proteins, and contribute to regulation of the cystic fibrosis transmembrane regulator in complex, cell- and tissue-specific ways. The protein interactomes of SLC26 polypeptides are under active investigation.
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Affiliation(s)
- Seth L Alper
- Renal Division and Division of Molecular and Vascular Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
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Lomasney KW, Hyland NP. The application of Ussing chambers for determining the impact of microbes and probiotics on intestinal ion transport. Can J Physiol Pharmacol 2013; 91:663-70. [DOI: 10.1139/cjpp-2013-0027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Host–microbe interactions have gained considerable attention in recent years with regards to their role in various organic disorders and diseases. In particular, research efforts have focused on the intestinal microbiota, where the largest and most diverse populations not only co-exist with the host, but also directly influence the state and function of the gastrointestinal (GI) tract. Moreover, both human and animal studies alike are now beginning to show a positive influence of probiotic bacteria on GI disorders associated with diarrhoea or constipation. Diarrheagenic GI diseases, such as those caused by Vibreo cholera or enterpathogenic Eschericia coli, have well-characterised interactions with the host that explain much of the observed symptoms, in particular severe diarrhoea. However, the mechanisms of action of nonpathogenic bacteria or probiotics on host physiology are less clearly understood. In the context of defining the mechanisms of action of probiotics in vitro, the Ussing chamber has proven to be a particularly useful tool. Here, we will present data from several studies that have defined molecular targets for microbes and putative probiotics in the regulation of intestinal secretory and absorptive function, and we will discuss these in the context of their application in pathogen- or inflammation-induced alterations in intestinal ion transport.
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Affiliation(s)
- Kevin W. Lomasney
- Department of Pharmacology and Therapeutics, Western Gateway Building, Western Road, University College Cork, Co. Cork, Ireland
- Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork, Co. Cork, Ireland
| | - Niall P. Hyland
- Department of Pharmacology and Therapeutics, Western Gateway Building, Western Road, University College Cork, Co. Cork, Ireland
- Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork, Co. Cork, Ireland
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Lenzen H, Lünnemann M, Bleich A, Manns MP, Seidler U, Jörns A. Downregulation of the NHE3-binding PDZ-adaptor protein PDZK1 expression during cytokine-induced inflammation in interleukin-10-deficient mice. PLoS One 2012; 7:e40657. [PMID: 22848392 PMCID: PMC3407152 DOI: 10.1371/journal.pone.0040657] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 06/11/2012] [Indexed: 12/21/2022] Open
Abstract
Background Impaired salt and water absorption is an important feature in the pathogenesis of diarrhea in inflammatory bowel disease (IBD). We analyzed the expression of proinflammatory cytokines in the infiltrating immune cells and the function and expression of the Na+/H+ exchanger isoform 3 (NHE3) and its regulatory PDZ-adaptor proteins NHERF1, NHERF2, and PDZK1 in the colon of interleukin-10–deficient (IL-10−/−) mice. Methodology/Principal Findings Gene and protein expression were analyzed by real-time reverse transcription polymerase chain reaction (qRT-PCR), in situ RT-PCR, and immunohistochemistry. NHE3 activity was measured fluorometrically in apical enterocytes within isolated colonic crypts. Mice developed chronic colitis characterized by a typical immune cell infiltration composed of T-lymphocytes and macrophages, with high levels of gene and protein expression of the proinflammatory cytokines interleukin-1β and tumor necrosis factor-α. In parallel, inducible nitric oxide synthase expression was increased while procaspase 3 expression was unaffected. Interferon-γ expression remained low. Although acid-activated NHE3 activity was significantly decreased, the inflammatory process did not affect its gene and protein expression or its abundance and localization in the apical membrane. However, expression of the PDZ-adaptor proteins NHERF2 and PDZK1 was downregulated. NHERF1 expression was unchanged. In a comparative analysis we observed the PDZK1 downregulation also in the DSS (dextran sulphate sodium) model of colitis. Conclusions/Significance The impairment of the absorptive function of the inflamed colon in the IL-10−/−mouse, in spite of unaltered NHE3 expression and localization, is accompanied by the downregulation of the NHE3-regulatory PDZ adaptors NHERF2 and PDZK1. We propose that the downregulation of PDZ-adaptor proteins may be an important factor leading to NHE3 dysfunction and diarrhea in the course of the cytokine-mediated inflammatory process in these animal models of IBD.
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Affiliation(s)
- Henrike Lenzen
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany.
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Xiao F, Juric M, Li J, Riederer B, Yeruva S, Singh AK, Zheng L, Glage S, Kollias G, Dudeja P, Tian DA, Xu G, Zhu J, Bachmann O, Seidler U. Loss of downregulated in adenoma (DRA) impairs mucosal HCO3(-) secretion in murine ileocolonic inflammation. Inflamm Bowel Dis 2012; 18:101-11. [PMID: 21557395 PMCID: PMC5426909 DOI: 10.1002/ibd.21744] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 03/28/2011] [Indexed: 12/12/2022]
Abstract
BACKGROUND Ileocolonic luminal pH has been reported to be abnormally low in inflammatory bowel disease (IBD) patients, and one of the causative factors may be reduced epithelial HCO(3)(-) secretory rate (J(HCO3)(-)). Disturbances in J(HCO3)(-) may occur due to inflammation-induced changes in the crypt and villous architecture, or due to the effect of proinflammatory cytokines on epithelial ion transporters. METHODS To discriminate between these possibilities, the tumor necrosis factor alpha (TNF-α) overexpressing (TNF(+/ΔARE)) mouse model was chosen, which displays high proinflammatory cytokine levels in both ileum and colon, but develops only mild colonic histopathology and diarrhea. HCO(3)(-) secretion, mRNA expression, immunohistochemistry, and fluid absorptive capacity were measured in ileal and mid-colonic mucosa of TNF(+/ΔARE) and wildtype (WT) (TNF(+/+)) mice in Ussing chambers, and in anesthetized mice in vivo. RESULTS The high basal J(HCO3)(-) observed in WT ileal and mid-colonic mucosa were luminal Cl(-) -dependent and strongly decreased in TNF(+/ΔARE) mice. Downregulated in adenoma (DRA) mRNA and protein expression was strongly decreased in TNF(+/ΔARE) ileocolon, whereas cystic fibrosis transmembrane conductance regulator (CFTR), Na(+) /H(+) exchanger 3 (NHE3), Na(+) /HCO(3)(-) cotransporter (NBC), and epithelial sodium channel (ENaC) expression was not significantly altered. This indicates that the severe defect in ileocolonic J(HCO3)(-) was due to DRA downregulation. Fluid absorption was severely depressed in the ileum but only mildly affected in the mid-distal colon, preventing the development of overt diarrhea. CONCLUSIONS Even mild ileocolonic inflammation may result in a decrease of epithelial HCO(3)(-) secretion, which may contribute to alterations in surface pH, intestinal flora, and mucus barrier properties.
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Affiliation(s)
- Fang Xiao
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany
| | - Marina Juric
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany
| | - Junhua Li
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany,Department of Nephrology, Tongji Hospital, Huazhong University of Science & Technology, China
| | - Brigitte Riederer
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany
| | - Sunil Yeruva
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany
| | - Anurag Kumar Singh
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany
| | - Lifei Zheng
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany,Department of Physiology, Capital Medical University, China
| | - Silke Glage
- Institute of Laboratory Animal Science, Hannover Medical School, Hannover, Germany
| | - George Kollias
- Biomedical Sciences Research Center Alexander Fleming, Greece
| | - Pradeep Dudeja
- Department of Medicine, University of Illinois, Champaign, Illinois
| | - De-An Tian
- Department of Gastroenterology, Tongji Hospital, Huazhong University of Science & Technology, China
| | - Gang Xu
- Department of Nephrology, Tongji Hospital, Huazhong University of Science & Technology, China
| | - Jinxia Zhu
- Department of Physiology, Capital Medical University, China
| | - Oliver Bachmann
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany
| | - Ursula Seidler
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany
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Abstract
Diarrhoea is a hallmark of intestinal inflammation. The mechanisms operating in acute inflammation of the intestine are well characterized and are related to regulatory changes induced by inflammatory mediators such as prostaglandins, cytokines or reactive oxygen species, along with leakage due to epithelial injury and changes in permeability. In chronic colitis, however, the mechanisms are less well known, but it is generally accepted that both secretory and absorptive processes are inhibited. These disturbances in ionic transport may be viewed as an adaptation to protracted inflammation of the intestine, since prolonged intense secretion may be physiologically unacceptable in the long term. Mechanistically, the changes in transport may be due to adjustments in the regulation of the different processes involved, to broader epithelial alterations or frank damage, or to modulation of the transportome in terms of expression. In the present review, we offer a summary of the existing evidence on the status of the transportome in chronic intestinal inflammation.
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32
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Bachmann O, Seidler U. News from the end of the gut--how the highly segmental pattern of colonic HCO₃⁻ transport relates to absorptive function and mucosal integrity. Biol Pharm Bull 2011; 34:794-802. [PMID: 21628874 DOI: 10.1248/bpb.34.794] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A number of transport mechanisms in the colonic epithelium contribute to HCO₃⁻ movement across the apical and basolateral membranes, but this ion has been largely regarded as a by-product of the transport functions it is involved in, such as NaCl or short chain fatty acid (SCFA) absorption. However, emerging data points to several specific roles of HCO₃⁻ for colonic epithelial physiology, including pH control in the colonic surface microenvironment, which is important for transport and immune functions, as well as the secretion and the rheological properties of the mucus gel. Furthermore, recent studies have demonstrated that colonic HCO₃⁻ transporters are expressed in a highly segmental as well as species-specific manner. This review summarizes recently gathered information on the functional anatomy of the colon, the roles of HCO₃⁻ in the colonic epithelium, colonic mucosal integrity, and the expression and function of HCO₃⁻ transporting mechanisms in health and disease.
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Affiliation(s)
- Oliver Bachmann
- Department of Gastroenterology, Hepatology, and Endocrinology, Hannover Medical School, Hannover, Germany
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33
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Yeruva S, Farkas K, Hubricht J, Rode K, Riederer B, Bachmann O, Cinar A, Rakonczay Z, Molnár T, Nagy F, Wedemeyer J, Manns M, Raddatz D, Musch MW, Chang EB, Hegyi P, Seidler U. Preserved Na(+)/H(+) exchanger isoform 3 expression and localization, but decreased NHE3 function indicate regulatory sodium transport defect in ulcerative colitis. Inflamm Bowel Dis 2010; 16:1149-61. [PMID: 20027604 DOI: 10.1002/ibd.21183] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND A major causative factor of diarrhea in ulcerative colitis (UC) patients is the loss of Na(+) absorptive capacity of the inflamed colonic mucosa. Potential contributing mechanisms include reduced driving force for active transport, and impaired expression, mislocalization, or defective transport function of Na(+) absorptive proteins. We therefore studied the expression, brush border membrane (BBM) localization, and transport capacity of the major intestinal Na(+) absorptive protein, the Na(+)/H(+) exchanger isoform 3 (NHE3) in biopsies from UC patients. METHODS In UC and control biopsies, inflammation was graded histologically, NHE3, tumor necrosis factor alpha (TNF-alpha), villin, as well as other housekeeping genes were analyzed by quantitative real-time polymerase chain reaction (PCR), BBM localization of NHE3 determined by immunohistochemistry, and confocal microscopy. Na(+) absorptive capacity was assessed by (22)Na(+) isotope fluxes and NHE3 transport activity measured microfluorometrically in BCECF-loaded surface colonocytes within isolated crypts. RESULTS In mildly, moderately, and severely inflamed sigmoid colon of UC patients, neither NHE3 mRNA expression nor the abundance of NHE3 in the BBM was significantly altered compared to other structural components of the BBM. However, Na(+) absorption was strongly reduced by approximately 80% and acid-activated NHE3 transport activity was significantly decreased in the surface cells of sigmoid colonic crypts even in moderately inflamed mucosa. CONCLUSIONS In the colonic mucosa of patients with active UC, NHE3 transport capacity was found significantly decreased despite correct NHE3 location and abundance in the brush border, independent of current treatment. These findings suggest functional NHE3 transport as a novel factor for inflammatory diarrhea in UC patients.
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Affiliation(s)
- Sunil Yeruva
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany
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Wongsamitkul N, Sirianant L, Muanprasat C, Chatsudthipong V. A plant-derived hydrolysable tannin inhibits CFTR chloride channel: a potential treatment of diarrhea. Pharm Res 2010; 27:490-7. [PMID: 20225391 DOI: 10.1007/s11095-009-0040-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
PURPOSE The present study examined the effects and mechanisms of actions of penta-m-digalloyl-glucose (PDG), a hydrolysable tannin extracted from Chinese gallnut, on cystic fibrosis transmembrane conductance regulator protein (CFTR). MATERIALS AND METHODS Fisher rat thyroid cells stably expressing human CFTR (FRT cells) and human intestinal T84 cells were used as cell models to investigate the effects of PDG on chloride secretion using short-circuit current analysis. The mechanisms by which PDG affected chloride secretion were also examined. Finally, in vivo antidiarrheal efficacy and effects of PDG on intestinal fluid absorption were evaluated in mouse closed-loop models. RESULTS In FRT cells, apical chloride current induced by forskolin, CPT-cAMP and apigenin were reversibly inhibited by PDG (IC50 approximately 10microM) without effects on intracellular cAMP content and cell viability. Similarly, in T84 cells, PDG effectively inhibited chloride secretion induced by forskolin and cholera toxin. However, it had no effect on calcium-induced chloride secretion. In mice, a single intraluminal injection of PDG (0.6 mg/kg) reduced cholera toxin-induced intestinal fluid secretion by 75% with no effect on intestinal fluid absorption. CONCLUSIONS PDG represents a new class of CFTR inhibitors. Further development of this class of compounds may provide a new therapeutic intervention for diarrhea.
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Affiliation(s)
- Nisa Wongsamitkul
- Toxicology Graduate Program, Faculty of Science, Mahidol University, Bangkok, Thailand
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35
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Wedenoja S, Höglund P, Holmberg C. Review article: the clinical management of congenital chloride diarrhoea. Aliment Pharmacol Ther 2010; 31:477-85. [PMID: 19912155 DOI: 10.1111/j.1365-2036.2009.04197.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Congenital chloride diarrhoea in a newborn is a medical emergency, requiring early diagnostics and treatment to prevent severe dehydration and infant mortality. While most of the 250 cases reported arise from Finland, Poland and Arab countries, single cases with this autosomal recessive disorder appear worldwide. Such congenital chloride diarrhoea rarity makes diagnosis difficult. Life-long salt substitution with NaCl and KCl stabilizes fluid, electrolyte and acid-base balance diagnosis. When properly treated, the long-term outcome is favourable. AIM To summarize data on congenital chloride diarrhoea diagnosis, pathophysiology and treatment, and to provide guidelines for both acute and long-term management of congenital chloride diarrhoea. METHODS Data are based on MEDLINE search for 'chloride diarrhoea', in addition to clinical experience in the treatment of the largest known series of patients. RESULTS Treatment of congenital chloride diarrhoea involves (i) life-long salt substitution; (ii) management of acute dehydration and hypokalaemia during gastroenteritis or other infections; and (iii) recognition and treatment of other manifestations of the disease, such as intestinal inflammation, renal impairment and male subfertility. CONCLUSIONS This review summarizes data on congenital chloride diarrhoea and provides guidelines for treatment. After being a mostly paediatric problem, adult patients constitute a rare challenge for gastroenterologists worldwide.
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Affiliation(s)
- S Wedenoja
- Hospital for Children and Adolescents, University of Helsinki, Helsinki, Finland.
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36
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Martínez-Augustin O, Romero-Calvo I, Suárez MD, Zarzuelo A, de Medina FS. Molecular bases of impaired water and ion movements in inflammatory bowel diseases. Inflamm Bowel Dis 2009; 15:114-27. [PMID: 18626965 DOI: 10.1002/ibd.20579] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The intestine is dedicated to the absorption of water and nutrients. Fine tuning of this process is necessary to maintain an adequate balance and inflammation disrupts the equilibrium. This review summarizes the current evidence in this field. Classical mechanisms proposed include alteration of epithelial integrity, augmented secretion, and reduced absorption. In addition, intestinal inflammation is associated with defects in epithelial barrier function. However, our understanding of the phenomenon has been complicated by the fact that ionic secretion is in fact diminished in vivo, even after inflammation has subsided. Inhibited ionic secretion can be reversed partially or totally in vitro by maneuvers such as blockade of inducible nitric oxide synthase or removal of the submucosal layer. Disturbances in ionic absorption are less well characterized but clearly involve both electroneutral and electrogenic Na(+) absorption. Altered ionic transport is associated with changes in the expression and function of the transporters, including the Na(+)/K(+) ATPase, the sodium/potassium/chloride cotransporter 1 (NKCC1), the sodium/hydrogen exchanger 3 (NHE3), and the epithelial sodium channel (ENaC), as well as to the modulation of intracellular signaling. Further investigation is needed in this area in order to provide an integrated paradigm of ionic transport in the inflamed intestine. In particular, we do not know exactly how diarrhea ensues in inflammation and, consequently, we do not have specific pharmacological tools to combat this condition effectively and without side effects. Moreover, whether transport disturbances are reversible independently of inflammatory control is unknown.
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Affiliation(s)
- Olga Martínez-Augustin
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, Granada, Spain
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37
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Li C, Krishnamurthy PC, Penmatsa H, Marrs KL, Wang XQ, Zaccolo M, Jalink K, Li M, Nelson DJ, Schuetz JD, Naren AP. Spatiotemporal coupling of cAMP transporter to CFTR chloride channel function in the gut epithelia. Cell 2008; 131:940-51. [PMID: 18045536 DOI: 10.1016/j.cell.2007.09.037] [Citation(s) in RCA: 148] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2007] [Revised: 07/17/2007] [Accepted: 09/13/2007] [Indexed: 12/12/2022]
Abstract
Cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-regulated chloride channel localized at apical cell membranes and exists in macromolecular complexes with a variety of signaling and transporter molecules. Here, we report that the multidrug resistance protein 4 (MRP4), a cAMP transporter, functionally and physically associates with CFTR. Adenosine-stimulated CFTR-mediated chloride currents are potentiated by MRP4 inhibition, and this potentiation is directly coupled to attenuated cAMP efflux through the apical cAMP transporter. CFTR single-channel recordings and FRET-based intracellular cAMP dynamics suggest that a compartmentalized coupling of cAMP transporter and CFTR occurs via the PDZ scaffolding protein, PDZK1, forming a macromolecular complex at apical surfaces of gut epithelia. Disrupting this complex abrogates the functional coupling of cAMP transporter activity to CFTR function. Mrp4 knockout mice are more prone to CFTR-mediated secretory diarrhea. Our findings have important implications for disorders such as inflammatory bowel disease and secretory diarrhea.
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Affiliation(s)
- Chunying Li
- Department of Physiology, The University of Tennessee Health Science Center, 894 Union Avenue, 420 Nash, Memphis, TN 38163, USA
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Dorwart MR, Shcheynikov N, Baker JMR, Forman-Kay JD, Muallem S, Thomas PJ. Congenital chloride-losing diarrhea causing mutations in the STAS domain result in misfolding and mistrafficking of SLC26A3. J Biol Chem 2008; 283:8711-22. [PMID: 18216024 DOI: 10.1074/jbc.m704328200] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Congenital chloride-losing diarrhea (CLD) is a genetic disorder causing watery stool and dehydration. Mutations in SLC26A3 (solute carrier 26 family member 3), which functions as a coupled Cl(-)/HCO(3)(-) exchanger, cause CLD. SLC26A3 is a membrane protein predicted to contain 12 transmembrane-spanning alpha-helices and a C-terminal STAS (sulfate transporters and anti-sigma-factor) domain homologous to the bacterial anti-sigma-factor antagonists. The STAS domain is required for SLC26A3 Cl(-)/HCO(3)(-) exchange function and for the activation of cystic fibrosis transmembrane conductance regulator by SLC26A3. Here we investigate the molecular mechanism(s) by which four CLD-causing mutations (DeltaY526/7, I544N, I675/6ins, and G702Tins) in the STAS domain lead to disease. In a heterologous mammalian expression system biochemical, immunohistochemical, and ion transport experiments suggest that the four CLD mutations cause SLC26A3 transporter misfolding and/or mistrafficking. Expression studies with the isolated STAS domain suggest that the I675/6ins and G702Tins mutations disrupt the STAS domain directly, whereas limited proteolysis experiments suggest that the DeltaY526/7 and I544N mutations affect a later step in the folding and/or trafficking pathway. The data suggest that these CLD-causing mutations cause disease by at least two distinct molecular mechanisms, both ultimately leading to loss of functional protein at the plasma membrane.
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Affiliation(s)
- Michael R Dorwart
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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Alrefai WA, Wen X, Jiang W, Katz JP, Steinbrecher KA, Cohen MB, Williams IR, Dudeja PK, Wu GD. Molecular cloning and promoter analysis of downregulated in adenoma (DRA). Am J Physiol Gastrointest Liver Physiol 2007; 293:G923-34. [PMID: 17761837 DOI: 10.1152/ajpgi.00029.2007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Downregulated in adenoma (DRA), also referred to as SLC26A3, is an intestinal anion transporter essential for intestinal chloride absorption. Mutations in DRA result in congenital chloride diarrhea. DRA expression has been shown to be induced by differentiation and to be modulated by cytokines. However, mechanisms of DRA gene transcription and its tissue-specific targeting have not yet been investigated. In this study, we cloned a 3,765-bp promoter fragment of human DRA gene and characterized its activity in human colonic LS174T and Caco-2 human colon cell lines. Primer extension identified a single transcriptional initiation site that was identical in both colon cancer cell lines and normal colon. Although hepatic nuclear factor HNF-4 is involved in the basal activity of DRA promoter, sodium butyrate induces its activity in LS174T cells via the binding of Yin Yang 1 (YY1) and GATA transcription factors to their respective cis-elements in promoter region. We also demonstrated a reduction in DRA promoter activity in Caco-2 cells by IFN-gamma, suggesting that regulation of DRA promoter by IFN-gamma may contribute to the pathophysiology of intestinal inflammation. Furthermore, we showed that the DRA promoter fragment is sufficient to drive human growth hormone transgene expression specifically in villus epithelial cells of the small intestine and in differentiated upper crypt and surface epithelial cells of the colon. Our studies provide evidence for the involvement of HNF-4, YY1, and GATA transcription factors in DRA expression in intestinal differentiated epithelial cells.
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Affiliation(s)
- Waddah A Alrefai
- University of Illinois at Chicago, Jesse Brown VA Medical Center, Medical Research Service, Chicago, IL 60612, USA.
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N/A. N/A. Shijie Huaren Xiaohua Zazhi 2004; 12:1631-1637. [DOI: 10.11569/wcjd.v12.i7.1631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/26/2023] Open
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Abstract
PURPOSE OF REVIEW Colitis is an inflammatory bowel disease that is confined to the colon and is characterized by a watery diarrhea that can also be accompanied by blood in the stool. The inflammation associated with colitis is generally confined to the mucosal and submucosal layers, although Crohn's colitis may be transmural. The principal functions of the colonic mucosa are to act as a barrier to the luminal contents of the intestinal tract and to facilitate the bidirectional transport of water and electrolytes. It is well established that barrier and transport defects occur in colitis and may be involved in pathogenesis. Consequently, this review discusses recent evidence of potential mechanisms that may be involved in the perturbation of mucosal transport and barrier functions in colitis and therapeutic advances to counteract these defects. RECENT FINDINGS Mechanisms responsible for transport dysfunction and barrier defects in colitis are discussed, including decreased activity of transport proteins such as CFTR, bacterial interactions with the epithelium, including understanding of the regulation and function of NOD-2, and altered expression of components of the intestinal barrier, such as mucins and multidrug resistance proteins. SUMMARY Recent advances in our understanding of how changes in barrier and transport function occur in colitis may illuminate the pathophysiology of this condition. The work discussed may also identify novel targets that are functionally altered in colitis, which potentially can be modulated therapeutically either with existing medications or with newer agents that are in development.
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Affiliation(s)
- Declan F McCole
- School of Medicine, University of California San Diego, San Diego, California, USA
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Walker J, Jijon HB, Churchill T, Kulka M, Madsen KL. Activation of AMP-activated protein kinase reduces cAMP-mediated epithelial chloride secretion. Am J Physiol Gastrointest Liver Physiol 2003; 285:G850-60. [PMID: 12869384 DOI: 10.1152/ajpgi.00077.2003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
AMP-activated protein kinase (AMPK) is activated in response to fluctuations in cellular energy status caused by oxidative stress. One of its targets is the cystic fibrosis transmembrane conductance regulator (CFTR), which is the predominant Cl- secretory channel in colonic tissue. The aim of this study was to determine the role of AMPK in the modulation of colonic chloride secretion under conditions of oxidative stress and chronic inflammation. Chloride secretion and AMPK activity were examined in colonic tissue from adult IL-10-deficient and wild-type 129 Sv/Ev mice in the presence and absence of pharmacological AMPK inhibitors and activators, respectively. Apical levels of CFTR were measured in brush-border membrane vesicles. Cell culture studies in human colonic T84 monolayers examined the effect of hydrogen peroxide and pharmacological activation of AMPK on forskolin-stimulated chloride secretion. Inflamed colons from IL-10-deficient mice exhibited hyporesponsiveness to forskolin stimulation in association with reductions in surface CFTR expression and increased AMPK activity. Inhibition of AMPK restored tissue responsiveness to forskolin, whereas stimulation of AMPK with 5-aminoimidazole-4-carboxamide-1-beta-d-ribofuranoside (AICAR) induced tissue hyporesponsivness in wild-type mice. T84 cells exposed to hydrogen peroxide demonstrated a time-dependent increase in AMPK activity and reduction of forskolin-stimulated chloride secretion. Inhibition of AMPK prevented the reduction in chloride secretion. Treatment of cells with the AMPK activator, AICAR, resulted in a decreased chloride secretion. In conclusion, AMPK activation is linked with reductions in cAMP-mediated epithelial chloride flux and may be a contributing factor to the hyporesponsiveness seen under conditions of chronic inflammation.
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Affiliation(s)
- John Walker
- Univ. of Alberta, 6146 Dentistry Pharmacy Bldg., Edmonton, AB, Canada T6G 2C2
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Chernova MN, Jiang L, Shmukler BE, Schweinfest CW, Blanco P, Freedman SD, Stewart AK, Alper SL. Acute regulation of the SLC26A3 congenital chloride diarrhoea anion exchanger (DRA) expressed in Xenopus oocytes. J Physiol 2003; 549:3-19. [PMID: 12651923 PMCID: PMC2342915 DOI: 10.1113/jphysiol.2003.039818] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Mutations in the human SLC26A3 gene, also known as down-regulated in adenoma (hDRA), cause autosomal recessive congenital chloride-losing diarrhoea (CLD). hDRA expressed in Xenopus oocytes mediated bidirectional Cl--Cl- and Cl--HCO3- exchange. In contrast, transport of oxalate was low, and transport of sulfate and of butyrate was undetectable. Two CLD missense disease mutants of hDRA were nonfunctional in oocytes. Truncation of up to 44 C-terminal amino acids from the putatively cytoplasmic C-terminal hydrophilic domain left transport function unimpaired, but deletion of the adjacent STAS (sulfate transporter anti-sigma factor antagonist) domain abolished function. hDRA-mediated Cl- transport was insensitive to changing extracellular pH, but was inhibited by intracellular acidification and activated by NH4+ at acidifying concentrations. These regulatory responses did not require the presence of either hDRA's N-terminal cytoplasmic tail or its 44 C-terminal amino acids, but they did require more proximate residues of the C-terminal cytoplasmic domain. Although only weakly sensitive to inhibition by stilbenes, hDRA was inhibited with two orders of magnitude greater potency by the anti-inflammatory drugs niflumate and tenidap. cAMP-insensitive Cl--HCO3- exchange mediated by hDRA gained modest cAMP sensitivity when co-expressed with cystic fibrosis transmembrane conductance regulator (CFTR). Despite the absence of hDRA transcripts in human cell lines derived from CFTR patients, DRA mRNA was present at wild-type levels in proximal colon and nearly so in the distal ileum of CFTR(-/-) mice. Thus, pharmacological modulation of DRA might be a useful adjunct treatment of cystic fibrosis.
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Affiliation(s)
- Marina N Chernova
- Molecular Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
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