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Barrett KE, McCole DF. Hydrogen peroxide scavenger, catalase, alleviates ion transport dysfunction in murine colitis. Clin Exp Pharmacol Physiol 2017; 43:1097-1106. [PMID: 27543846 DOI: 10.1111/1440-1681.12646] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 08/11/2016] [Accepted: 08/18/2016] [Indexed: 12/16/2022]
Abstract
Reactive oxygen species (ROS) such as hydrogen peroxide (H2 O2 ) contribute to epithelial damage and ion transport dysfunction (key events in inflammatory diarrhoea) in inflammatory bowel disease (IBD). The aim of this study was to identify if H2 O2 mediates suppression of colonic ion transport function in the murine dextran sulfate sodium (DSS) colitis model by using the H2 O2 degrading enzyme, catalase. Colitis was induced by administering DSS (4%) in drinking water for 5 days followed by 3 days on normal H2 O. Mice were administered either pegylated catalase or saline at day -1, 0 and +1 of DSS treatment. Ion transport responses to the Ca2+ -dependent agonist, carbachol (CCh), or the cAMP-dependent agonist, forskolin, were measured across distal colonic mucosa mounted in Ussing chambers. Parameters of DSS-induced inflammation (loss in body weight, decreased colon length, altered stool consistency), were only partially alleviated by catalase while histology was only minimally improved. However, catalase significantly reversed the DSS-induced reduction in baseline ion transport as well as colonic Isc responses to CCh. However, ion transport responses to forskolin were not significantly restored. Catalase also reduced activation of ERK MAP kinase in the setting of colitis, and increased expression of the Na+ -K+ -2Cl- cotransporter, NKCC1, consistent with restoration of ion transport function. Ex vivo treatment of inflamed colonic mucosae with catalase also partially restored ion transport function. Therefore, catalase partially prevents, and rescues, the loss of ion transport properties in DSS colitis even in the setting of unresolved tissue inflammation. These findings indicate a prominent role for ROS in ion transport dysfunction in colitis and may suggest novel strategies for the treatment of inflammatory diarrhoea.
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Affiliation(s)
- Kim E Barrett
- Division of Gastroenterology, University of California, San Diego School of Medicine, La Jolla, CA, USA
| | - Declan F McCole
- Division of Biomedical Sciences, School of Medicine, University of California Riverside, Riverside, CA, USA.
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52
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Sarker R, Cha B, Kovbasnjuk O, Cole R, Gabelli S, Tse CM, Donowitz M. Phosphorylation of NHE3-S 719 regulates NHE3 activity through the formation of multiple signaling complexes. Mol Biol Cell 2017; 28:1754-1767. [PMID: 28495796 PMCID: PMC5491184 DOI: 10.1091/mbc.e16-12-0862] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/09/2017] [Accepted: 05/04/2017] [Indexed: 12/02/2022] Open
Abstract
CK2 regulates NHE3 by phosphorylating a single C-terminal amino acid, which, when mutated, reduces basal NHE3 activity and its acute stimulation and inhibition. It also is necessary for binding of proteins throughout the C-terminus, which means that it determines the C-terminal structure. Casein kinase 2 (CK2) binds to the NHE3 C-terminus and constitutively phosphorylates a downstream site (S719) that accounts for 40% of basal NHE3 activity. The role of CK2 in regulation of NHE3 activity in polarized Caco-2/bbe cells was further examined by mutation of NHE3-S719 to A (not phosphorylated) or D (phosphomimetic). NHE3-S719A but not -S719D had multiple changes in NHE3 activity: 1) reduced basal NHE3 activity—specifically, inhibition of the PI3K/AKT-dependent component; 2) reduced acute stimulation of NHE3 activity by LPA/LPA5R stimulation; and 3) reduced acute inhibition of NHE3 activity—specifically, elevated Ca2+ related (carbachol/Ca2+ ionophore), but there was normal inhibition by forskolin and hyperosmolarity. The S719A mutant had reduced NHE3 complex size, reduced expression in lipid rafts, increased BB mobile fraction, and reduced binding to multiple proteins that bind throughout the NHE3 intracellular C-terminus, including calcineurin homologous protein, the NHERF family and SNX27 (related PDZ domains). These studies show that phosphorylation of the NHE3 at a single amino acid in the distal part of the C-terminus affects multiple aspects of NHE3 complex formation and changes the NHE3 lipid raft distribution, which cause changes in specific aspects of basal as well as acutely stimulated and inhibited Na+/H+ exchange activity.
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Affiliation(s)
- Rafiquel Sarker
- Department of Physiology and Department of Medicine, GI Division, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Boyoung Cha
- Department of Physiology and Department of Medicine, GI Division, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Olga Kovbasnjuk
- Department of Physiology and Department of Medicine, GI Division, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Robert Cole
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Sandra Gabelli
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Chung Ming Tse
- Department of Physiology and Department of Medicine, GI Division, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Mark Donowitz
- Department of Physiology and Department of Medicine, GI Division, Johns Hopkins University School of Medicine, Baltimore, MD 21205
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Janecke AR, Heinz-Erian P, Müller T. Reduced NHE3 activity results in congenital diarrhea and can predispose to inflammatory bowel disease. Am J Physiol Regul Integr Comp Physiol 2017; 312:R311. [DOI: 10.1152/ajpregu.00545.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 01/08/2017] [Indexed: 11/22/2022]
Affiliation(s)
- Andreas R. Janecke
- Department of Pediatrics I, Medical University of Innsbruck, Innsbruck, Austria
| | - Peter Heinz-Erian
- Department of Pediatrics I, Medical University of Innsbruck, Innsbruck, Austria
| | - Thomas Müller
- Department of Pediatrics I, Medical University of Innsbruck, Innsbruck, Austria
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54
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Kim SE, Choo J, Yoon J, Chu JR, Bae YJ, Lee S, Park T, Sung MK. Genome-wide analysis identifies colonic genes differentially associated with serum leptin and insulin concentrations in C57BL/6J mice fed a high-fat diet. PLoS One 2017; 12:e0171664. [PMID: 28170448 PMCID: PMC5295695 DOI: 10.1371/journal.pone.0171664] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 01/24/2017] [Indexed: 02/07/2023] Open
Abstract
Obesity-induced chronic inflammation is known to increase the risk of ulcerative colitis, Crohn's disease, and colorectal cancer. Accumulating evidence suggests that leptin and insulin are key molecules linking obesity with diseases of the lower intestine. Here, we identified serum phenotype-associated genes in the colon of diet-induced obese mice as early biomarkers of obesity-associated colonic diseases. C57BL/6J mice were fed with either normal diet (ND, 15% of fat calories) or high-fat diet (HFD, 45% of fat calories) for 8 weeks. Serum concentrations of insulin, insulin-like growth factor-1 (IGF-1), leptin, and adiponectin were measured as obesity-related phenotypic markers. Genome-wide gene expression profiles of colon tissue were determined, followed by statistical analyses to detect differentially expressed and serum phenotype-associated genes. HFD-fed mice showed higher serum concentrations of leptin (P < 0.001) and insulin (P < 0.01) than those in the ND group, whereas serum IGF-1 and adiponectin concentrations did not differ between the two dietary groups. Among differentially expressed genes affected by HFD, 135, 128, 110, and 341 genes were associated with serum levels of leptin, insulin, IGF-1, and adiponectin, respectively. We identified 17 leptin-associated genes and 4 insulin-associated genes that inversely responded to HFD and ND. Among these, leptin-associated Peli3 (Pellino E3 ubiquitin protein ligase family member 3), Creb1 (cAMP responsive element binding protein 1), and Enpp2 (ectonucleotide pyrophosphatase/phosphodiesterase 2, autotaxin) and insulin-associated Centg1 (AGAP2, ArfGAP with GTPase domain) are reported to play a role either in obesity or colonic diseases. mRNA expression of these genes was validated by RT-qPCR. Our data suggest Peli3, Creb1, Enpp2, and Centg1 as potential early biomarker candidates for obesity-induced pathophysiological changes in the colon. Future studies verifying the function of these candidates are needed for the prevention, early detection, and treatment of colon diseases.
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Affiliation(s)
- Sung-Eun Kim
- Department of Food and Nutrition, Sookmyung Women’s University, Seoul, Republic of Korea
| | - Jinsil Choo
- Department of Life Systems, Sookmyung Women’s University, Seoul, Republic of Korea
| | - Joon Yoon
- Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul, Republic of Korea
| | - Jae Ryang Chu
- Department of Life Systems, Sookmyung Women’s University, Seoul, Republic of Korea
| | - Yun Jung Bae
- Division of Food Science and Culinary Arts, Shinhan University, Gyeonggi-do, Republic of Korea
| | - Seungyeoun Lee
- Department of Mathematics and Statistics, Sejong University, Seoul, Republic of Korea
| | - Taesung Park
- Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul, Republic of Korea
- Department of Statistics, Seoul National University, Seoul, Republic of Korea
| | - Mi-Kyung Sung
- Department of Food and Nutrition, Sookmyung Women’s University, Seoul, Republic of Korea
- * E-mail:
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55
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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 2017; 13:659-665. [PMID: 27553076 PMCID: PMC5501083 DOI: 10.1016/j.nano.2016.08.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [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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Camilleri M, Sellin JH, Barrett KE. Pathophysiology, Evaluation, and Management of Chronic Watery Diarrhea. Gastroenterology 2017; 152:515-532.e2. [PMID: 27773805 PMCID: PMC5285476 DOI: 10.1053/j.gastro.2016.10.014] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 09/21/2016] [Accepted: 10/11/2016] [Indexed: 02/08/2023]
Abstract
Chronic watery diarrhea poses a diagnostic and therapeutic challenge and is often a disabling condition for patients. Although acute diarrhea is likely to be caused by infection, the causes of chronic diarrhea (>4 weeks in duration) are more elusive. We review the pathophysiology, diagnosis, and treatment of chronic diarrhea. Drawing on recent insights into the molecular mechanisms of intestinal epithelial transport and barrier function, we discuss how diarrhea can result from a decrease in luminal solute absorption, an increase in secretion, or both, as well as derangements in barrier properties. We also describe the various extraepithelial factors that activate diarrheal mechanisms. Finally, clinical evaluation and tests used in the assessment of patients presenting with chronic diarrhea are reviewed, and an algorithm guiding therapeutic decisions and pharmacotherapy is presented.
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Affiliation(s)
- Michael Camilleri
- Clinical Enteric Neuroscience Translational and Epidemiological Research, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota.
| | - Joseph H. Sellin
- Division of Gastroenterology, Department of Medicine, Baylor College of Medicine, Houston, TX
| | - Kim E. Barrett
- Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, CA
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Kumar A, Anbazhagan AN, Coffing H, Chatterjee I, Priyamvada S, Gujral T, Saksena S, Gill RK, Alrefai WA, Borthakur A, Dudeja PK. Lactobacillus acidophilus counteracts inhibition of NHE3 and DRA expression and alleviates diarrheal phenotype in mice infected with Citrobacter rodentium. Am J Physiol Gastrointest Liver Physiol 2016; 311:G817-G826. [PMID: 27634011 PMCID: PMC5130543 DOI: 10.1152/ajpgi.00173.2016] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 09/12/2016] [Indexed: 01/31/2023]
Abstract
Impaired absorption of electrolytes is a hallmark of diarrhea associated with inflammation or enteric infections. Intestinal epithelial luminal membrane NHE3 (Na+/H+ exchanger 3) and DRA (Down-Regulated in Adenoma; Cl-/HCO3- exchanger) play key roles in mediating electroneutral NaCl absorption. We have previously shown decreased NHE3 and DRA function in response to short-term infection with enteropathogenic E coli (EPEC), a diarrheal pathogen. Recent studies have also shown substantial downregulation of DRA expression in a diarrheal model of infection with Citrobacter rodentium, the mouse counterpart of EPEC. Since our previous studies showed that the probiotic Lactobacillus acidophilus (LA) increased DRA and NHE3 function and expression and conferred protective effects in experimental colitis, we sought to evaluate the efficacy of LA in counteracting NHE3 and DRA inhibition and ameliorating diarrhea in a model of C rodentium infection. FVB/N mice challenged with C rodentium [1 × 109 colony-forming units (CFU)] with or without administration of live LA (3 × 109 CFU) were assessed for NHE3 and DRA mRNA and protein expression, mRNA levels of carbonic anhydrase, diarrheal phenotype (assessed by colonic weight-to-length ratio), myeloperoxidase activity, and proinflammatory cytokines. LA counteracted C rodentium-induced inhibition of colonic DRA, NHE3, and carbonic anhydrase I and IV expression and attenuated diarrheal phenotype and MPO activity. Furthermore, LA completely blocked C rodentium induction of IL-1β, IFN-γ, and CXCL1 mRNA and C rodentium-induced STAT3 phosphorylation. In conclusion, our data provide mechanistic insights into antidiarrheal effects of LA in a model of infectious diarrhea and colitis.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Alip Borthakur
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago and Jesse Brown VA Medical Center, Chicago, Illinois
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Congenital Sodium Diarrhea: A Form of Intractable Diarrhea, With a Link to Inflammatory Bowel Disease. J Pediatr Gastroenterol Nutr 2016; 63:170-6. [PMID: 26835907 DOI: 10.1097/mpg.0000000000001139] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Congenital diarrheal disorders (CDDs) represent a group of challenging clinical conditions for pediatricians because of the severity of the presentation and the broad range of possible differential diagnoses. CDDs arise from alterations in the transport of nutrients and electrolytes across the intestinal mucosa, from enterocyte and enteroendocrine cell differentiation and/or polarization defects, and from the modulation of the intestinal immune response. Advances were made recently in deciphering the etiology and pathophysiology of one of these disorders, congenital sodium diarrhea (CSD). CSD refers to an intractable diarrhea of intrauterine onset with high fecal sodium loss. CSD is clinically and genetically heterogeneous. A syndromic form of CSD features choanal and intestinal atresias as well as recurrent corneal erosions. Small bowel histology frequently detects an epithelial "tufting" dysplasia. It is autosomal recessively inherited, and caused by SPINT2 mutations. The nonsyndromic form of CSD can be caused by dominant activating mutations in GUCY2C, encoding intestinal receptor guanylate cyclase C (GC-C), and by autosomal recessive SLC9A3 loss-of-function mutations. SLC9A3 encodes Na/H antiporter 3, the major intestinal brush border Na/H exchanger, and a downstream target of GC-C. A number of patients with GUCY2C and SLC9A3 mutations developed inflammatory bowel disease. Both the number of recognized CDD forms as well as the number of underlying disease genes are gradually increasing. Knowledge of these CDD genes enables noninvasive, next-generation gene panel-based testing to facilitate an early diagnosis in CDD. Primary Na/H antiporter 3 and GC-C malfunction is implicated as a predisposition for inflammatory bowel disease in subset of patients.
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Pérez-Torras S, Iglesias I, Llopis M, Lozano JJ, Antolín M, Guarner F, Pastor-Anglada M. Transportome Profiling Identifies Profound Alterations in Crohn's Disease Partially Restored by Commensal Bacteria. J Crohns Colitis 2016; 10:850-9. [PMID: 26874350 DOI: 10.1093/ecco-jcc/jjw042] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND AND AIMS Several transport alterations have been described in intestinal inflammatory diseases. This is relevant because the primary function of the intestine is nutrient and mineral absorption. However, analysis of the transportome as a whole and the effect of commensal bacteria on it have not been addressed so far. METHODS Five healthy and 6 Crohn's disease (CD) samples were hybridized to human HT-12 V4 Illumina GeneChip. Results were validated by reverse transcription-polymerase chain reaction (RT-PCR) analysis and with additional array data. Organ culture assays were performed from mucosa ileal wall specimens collected at surgery. Samples were incubated with or without commensal bacteria for 4 hours. Finally, RNA was isolated for microarray processing. RESULTS The analysis of CD versus healthy ileal mucosa demonstrated upregulation of previously described genes involved in immunity and the inflammatory response in this disease. Interestingly, whole transcriptional analysis revealed profound alterations in the transportome profile. Sixty-two solute carrier (SLC) transporters displayed different expression patterns, most of them being downregulated. Changes were confirmed by RT-PCR in a randomly chosen subset of SLCs. A large number of amino acid transporters and most members of the enteric purinome were found to be altered. Most of these proteins were found at the apical membrane of the enterocyte, which could impair both amino acid absorption and purinergic signalling. Treatment of ileum specimen explants with commensal bacteria restored almost all CD transportome alterations. CONCLUSIONS These results describe the altered transportome profile in CD and open the possibility of restoring transportome complications with commensal bacteria.
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Affiliation(s)
- Sandra Pérez-Torras
- Molecular Pharmacology and Experimental Therapeutics, Department of Biochemistry and Molecular Biology, Institute of Biomedicine, University of Barcelona, Barcelona, Spain Oncology Program, CIBERehd, National Biomedical Research Institute on Liver and Gastrointestinal Diseases, Instituto de Salud Carlos III, Barcelona, Spain
| | - Ingrid Iglesias
- Molecular Pharmacology and Experimental Therapeutics, Department of Biochemistry and Molecular Biology, Institute of Biomedicine, University of Barcelona, Barcelona, Spain Oncology Program, CIBERehd, National Biomedical Research Institute on Liver and Gastrointestinal Diseases, Instituto de Salud Carlos III, Barcelona, Spain
| | - Marta Llopis
- Digestive System Research Unit, University Hospital Vall d'Hebron, CIBEREHD, Passeig Vall d'Hebron 119-129, Barcelona 08035, Spain
| | | | - María Antolín
- Digestive System Research Unit, University Hospital Vall d'Hebron, CIBEREHD, Passeig Vall d'Hebron 119-129, Barcelona 08035, Spain
| | - Francisco Guarner
- Digestive System Research Unit, University Hospital Vall d'Hebron, CIBEREHD, Passeig Vall d'Hebron 119-129, Barcelona 08035, Spain
| | - Marçal Pastor-Anglada
- Molecular Pharmacology and Experimental Therapeutics, Department of Biochemistry and Molecular Biology, Institute of Biomedicine, University of Barcelona, Barcelona, Spain Oncology Program, CIBERehd, National Biomedical Research Institute on Liver and Gastrointestinal Diseases, Instituto de Salud Carlos III, Barcelona, Spain
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Mechanisms Underlying Dysregulation of Electrolyte Absorption in Inflammatory Bowel Disease-Associated Diarrhea. Inflamm Bowel Dis 2016; 22:E17-8. [PMID: 27104826 DOI: 10.1097/mib.0000000000000778] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
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61
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Anbazhagan AN, Priyamvada S, Alakkam A, Kumar A, Borthakur A, Saksena S, Gill RK, Alrefai WA, Dudeja PK. Transcriptional modulation of SLC26A3 (DRA) by sphingosine-1-phosphate. Am J Physiol Gastrointest Liver Physiol 2016; 310:G1028-35. [PMID: 27079615 PMCID: PMC4935485 DOI: 10.1152/ajpgi.00308.2015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 04/12/2016] [Indexed: 01/31/2023]
Abstract
SLC26A3 or Downregulated in adenoma (DRA) is the major Cl(-)/HCO3 (-) exchanger involved in electroneutral NaCl absorption in the mammalian intestine. Alterations in DRA function and expression have been implicated in diarrheal diseases associated with inflammation or infection. Therefore, agents that upregulate DRA activity may serve as potential antidiarrheals. In this regard, sphingosine-1-phosphate (S1P), a member of the bioactive sphingolipid family, has been shown to modulate various cellular processes including improvement of intestinal barrier function. However, the role of S1P in modulating intestinal chloride absorption by regulating DRA is not known. Therefore, the present studies were designed to examine the direct effects of S1P on apical Cl(-)/HCO3 (-) exchange activity and DRA expression. S1P significantly increased Cl(-)/HCO3 (-) exchange activity and also significantly increased DRA mRNA and protein expression. Increased DRA mRNA by S1P was accompanied by enhanced DRA promoter activity, indicating involvement of transcriptional mechanisms. The specific S1P receptor subtype-2 (S1PR2) antagonist JTE-013 blocked the stimulatory effects of S1P on DRA promoter activity, indicating the involvement of S1PR2 S1P-mediated increase in DRA promoter activity involved PI3K/Akt pathway. Progressive deletions of the DRA promoter indicated that the putative S1P-responsive elements are present in the -790/-398 region of the DRA promoter. Furthermore, results obtained from electrophoretic mobility shift assay showed that S1P stimulated DRA promoter activity via increased binding of Ying-Yang1 (YY1) in the S1P-responsive region. In conclusion, transcriptional modulation of DRA expression and function in response to S1P through a PI3/Akt pathway represents a novel role of S1P as a potential proabsorptive agent.
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Affiliation(s)
- Arivarasu N. Anbazhagan
- 2Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Shubha Priyamvada
- 2Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Anas Alakkam
- 2Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Anoop Kumar
- 2Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Alip Borthakur
- 2Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Seema Saksena
- 1Jesse Brown VA Medical Center, Research Service, Chicago, Illinois; and ,2Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Ravinder K. Gill
- 2Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Waddah A. Alrefai
- 1Jesse Brown VA Medical Center, Research Service, Chicago, Illinois; and ,2Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Pradeep K. Dudeja
- 1Jesse Brown VA Medical Center, Research Service, Chicago, Illinois; and ,2Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
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