1
|
Sawant H, Selvaraj R, Manogaran P, Borthakur A. Intestinal Epithelial Creatine Transporter SLC6A8 Dysregulation in Inflammation and in Response to Adherent Invasive E. coli Infection. Int J Mol Sci 2024; 25:6537. [PMID: 38928243 PMCID: PMC11204174 DOI: 10.3390/ijms25126537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2024] [Revised: 06/07/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024] Open
Abstract
Creatine transporter (CrT1) mediates cellular uptake of creatine (Cr), a nutrient pivotal in maintaining energy homeostasis in various tissues including intestinal epithelial cells (IECs). The impact of CrT1 deficiency on the pathogenesis of various psychiatric and neurological disorders has been extensively investigated. However, there are no studies on its regulation in IECs in health and disease. Current studies have determined differential expression of CrT1 along the length of the mammalian intestine and its dysregulation in inflammatory bowel disease (IBD)-associated inflammation and Adherent Invasive E. coli (AIEC) infection. CrT1 mRNA and protein levels in normal intestines and their alterations in inflammation and following AIEC infection were determined in vitro in model IECs (Caco-2/IEC-6) and in vivo in SAMP1/YitFc mice, a model of spontaneous ileitis resembling human IBD. CrT1 is differentially expressed in different regions of mammalian intestines with its highest expression in jejunum. In vitro, CrT1 function (Na+-dependent 14C-Cr uptake), expression and promoter activity significantly decreased following TNFα/IL1β treatments and AIEC infection. SAMP1 mice and ileal organoids generated from SAMP1 mice also showed decreased CrT1 mRNA and protein compared to AKR controls. Our studies suggest that Cr deficiency in IECs secondary to CrT1 dysregulation could be a key factor contributing to IBD pathogenesis.
Collapse
Affiliation(s)
| | | | | | - Alip Borthakur
- Department of Clinical and Translational Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA; (H.S.); (R.S.); (P.M.)
| |
Collapse
|
2
|
Sun Z, Huang S, Yan X, Zhang X, Hao Y, Jiang L, Dai Z. Living, Heat-Killed Limosilactobacillus mucosae and Its Cell-Free Supernatant Differentially Regulate Colonic Serotonin Receptors and Immune Response in Experimental Colitis. Nutrients 2024; 16:468. [PMID: 38398793 PMCID: PMC10893098 DOI: 10.3390/nu16040468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 01/27/2024] [Accepted: 01/29/2024] [Indexed: 02/25/2024] Open
Abstract
Lactobacillus species have been shown to alleviate gut inflammation and oxidative stress. However, the effect of different lactobacilli components on gut inflammation has not been well studied. This study aims to identify the differences in the effect and mechanisms of different forms and components of Limosilactobacillus mucosae (LM) treatment in the alleviation of gut inflammation using a colitis mouse model that is induced by dextran sodium sulfate (DSS). Seventy-two C57BL/6 mice were divided into six groups: control, DSS, live LM+DSS (LM+DSS), heat-killed LM+DSS (HKLM+DSS), LM cell-free supernatant + DSS (LMCS+DSS), and MRS medium + DSS (MRS+DSS). The mice were treated with different forms and components of LM for two weeks before DSS treatment. After that, the mice were sacrificed for an assessment of their levels of inflammatory cytokines, serotonin (5-HT) receptors (HTRs), and tryptophan metabolites. The results showed that, compared to other treatments, LMCS was more effective (p < 0.05) in the alleviation of DSS-induced body weight loss and led to an increase in the disease activity index score. All three forms and components of LM increased (p < 0.05) the levels of indole-3-acetic acid but reduced (p < 0.05) the levels of 5-HT in the colon. HKLM or LMCS reduced (p < 0.05) the percentages of CD3+CD8+ cytotoxic T cells but increased (p < 0.05) the percentages of CD3+CD4+ T helper cells in the spleen. LM or HKLM increased (p < 0.05) abundances of CD4+Foxp3+ regulatory T cells in the spleen. The LM and LMCS treatments reduced (p < 0.05) the expression of the pro-inflammatory cytokines Il6 and Il17a. The mice in the HKLM+DSS group had higher (p < 0.05) mRNA levels of the anti-inflammatory cytokine Il10, the cell differentiation and proliferation markers Lgr5 and Ki67, the 5-HT degradation enzyme Maoa, and HTRs (Htr1a, Htr2a, and Htr2b) in the colon. All three forms and components of LM reduced the phosphorylation of STAT3. The above findings can help to optimize the functionality of probiotics and develop new dietary strategies that aid in the maintenance of a healthy gut.
Collapse
Affiliation(s)
- Zhiyuan Sun
- State Key Laboratory of Animal Nutrition and Feeding, China Agricultural University, Beijing 100193, China; (Z.S.); (X.Y.); (X.Z.); (Y.H.); (L.J.)
| | - Siqi Huang
- College of Animal Science and Technology, China Agricultural University, Beijing 100193, China;
| | - Xing Yan
- State Key Laboratory of Animal Nutrition and Feeding, China Agricultural University, Beijing 100193, China; (Z.S.); (X.Y.); (X.Z.); (Y.H.); (L.J.)
| | - Xiuwen Zhang
- State Key Laboratory of Animal Nutrition and Feeding, China Agricultural University, Beijing 100193, China; (Z.S.); (X.Y.); (X.Z.); (Y.H.); (L.J.)
| | - Youling Hao
- State Key Laboratory of Animal Nutrition and Feeding, China Agricultural University, Beijing 100193, China; (Z.S.); (X.Y.); (X.Z.); (Y.H.); (L.J.)
| | - Lili Jiang
- State Key Laboratory of Animal Nutrition and Feeding, China Agricultural University, Beijing 100193, China; (Z.S.); (X.Y.); (X.Z.); (Y.H.); (L.J.)
| | - Zhaolai Dai
- State Key Laboratory of Animal Nutrition and Feeding, China Agricultural University, Beijing 100193, China; (Z.S.); (X.Y.); (X.Z.); (Y.H.); (L.J.)
| |
Collapse
|
3
|
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: 5] [Impact Index Per Article: 5.0] [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.
Collapse
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.
| |
Collapse
|
4
|
Lactobacillus acidophilus Mitigates Osteoarthritis-Associated Pain, Cartilage Disintegration and Gut Microbiota Dysbiosis in an Experimental Murine OA Model. Biomedicines 2022; 10:biomedicines10061298. [PMID: 35740320 PMCID: PMC9220766 DOI: 10.3390/biomedicines10061298] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 05/27/2022] [Accepted: 05/30/2022] [Indexed: 02/04/2023] Open
Abstract
To test probiotic therapy for osteoarthritis (OA), we administered Lactobacillus acidophilus (LA) by oral gavage (2×/week) after induction of OA by partial medial meniscectomy (PMM). Pain was assessed by von Frey filament and hot plate testing. Joint pathology and pain markers were comprehensively analyzed in knee joints, spinal cords, dorsal root ganglia and distal colon by Safranin O/fast green staining, immunofluorescence microscopy and RT-qPCR. LA acutely reduced inflammatory knee joint pain and prevented further OA progression. The therapeutic efficacy of LA was supported by a significant reduction of cartilage-degrading enzymes, pain markers and inflammatory factors in the tissues we examined. This finding suggests a likely clinical effect of LA on OA. The effect of LA treatment on the fecal microbiome was assessed by 16S rRNA gene amplicon sequencing analysis. LA significantly altered the fecal microbiota compared to vehicle-treated mice (PERMANOVA p < 0.009). Our pre-clinical OA animal model revealed significant OA disease modifying effects of LA as reflected by rapid joint pain reduction, cartilage protection, and reversal of dysbiosis. Our findings suggest that LA treatment has beneficial systemic effects that can potentially be developed as a safe OA disease-modifying drug (OADMD).
Collapse
|
5
|
Wu Y, Nie C, Luo R, Qi F, Bai X, Chen H, Niu J, Chen C, Zhang W. Effects of Multispecies Probiotic on Intestinal Microbiota and Mucosal Barrier Function of Neonatal Calves Infected With E. coli K99. Front Microbiol 2022; 12:813245. [PMID: 35154038 PMCID: PMC8826468 DOI: 10.3389/fmicb.2021.813245] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 11/25/2021] [Indexed: 12/13/2022] Open
Abstract
Altered gut microbiota are implicated in inflammatory neonatal calf diarrhea caused by E. coli K99. Beneficial probiotics are used to modulate gut microbiota. However, factors that mediate host-microbe interactions remain unclear. We evaluated the effects of a combination of multispecies probiotics (MSP) on growth, intestinal epithelial development, intestinal immune function and microbiota of neonatal calves infected with E. coli K99. Twelve newborn calves were randomly assigned as follows: C (control, without MSP); D (E. coli O78:K99 + gentamycin); and P (E. coli O78:K99 + supplemental MSP). All groups were studied for 21 d. MSP supplementation significantly (i) changed fungal Chao1 and Shannon indices of the intestine compared with group D; (ii) reduced the relative abundance of Bacteroides and Actinobacteria, while increasing Bifidobacteria, Ascomycetes, and Saccharomyces, compared with groups C and D; (iii) improved duodenal and jejunal mucosal SIgA and total Short Chain Fatty Acids (SCFA) concentrations compared with group D; (iv) increased relative ZO-1 and occludin mRNA expression in jejunal mucosa compared with group D; and (v) enhanced intestinal energy metabolism and defense mechanisms of calves by reducing HSP90 expression in E. coli K99, thereby alleviating the inflammatory response and promoting recovery of mucosal function. Our research may provide direct theoretical support for future applications of MSP in ruminant production.
Collapse
Affiliation(s)
- Yanyan Wu
- College of Animal Science and Technology, Shihezi University, Shihezi, China
| | - Cunxi Nie
- College of Animal Science and Technology, Shihezi University, Shihezi, China
| | - Ruiqing Luo
- Xinjiang Tianshan Junken Animal Husbandry Co., Ltd., Shihezi, China
| | - Fenghua Qi
- College of Animal Science and Technology, Shihezi University, Shihezi, China
| | - Xue Bai
- College of Animal Science and Technology, Shihezi University, Shihezi, China
| | - Hongli Chen
- Xinjiang Tianshan Junken Animal Husbandry Co., Ltd., Shihezi, China
| | - Junli Niu
- College of Animal Science and Technology, Shihezi University, Shihezi, China
| | - Chen Chen
- College of Animal Science and Technology, Shihezi University, Shihezi, China
| | - Wenju Zhang
- College of Animal Science and Technology, Shihezi University, Shihezi, China
| |
Collapse
|
6
|
Quach A, Jayaratne RR, Lee BJ, Ibeawuchi SR, Lim E, Das S, Barrett KE. Diarrheal pathogenesis in Salmonella infection may result from an imbalance in intestinal epithelial differentiation through reduced Notch signaling. J Physiol 2022; 600:1851-1865. [PMID: 35100665 DOI: 10.1113/jp282585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 01/20/2022] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Salmonella is a leading foodborne pathogen known to cause high chloride content diarrhea. Salmonella infection of murine enteroid-derived monolayers decreased DRA expression. Salmonella infection resulted in upregulation of the secretory epithelial marker ATOH1, the goblet cell marker Muc2, and the enteroendocrine cell marker ChgA. Downregulation of DRA may result from infection-induced Notch inhibition, as reflected by decreased expression of Notch intracellular domain and Hes1, as well as from decreased HNF1α signaling. The imbalance in intestinal epithelial differentiation favoring secretory over absorptive cell types is a possible mechanism by which Salmonella elicits diarrhea and may be relevant therapeutically. ABSTRACT Infections with non-typhoidal Salmonella spp. represent the most burdensome foodborne illnesses worldwide, yet despite their prevalence, the mechanism through which Salmonella elicits diarrhea is not entirely known. Intestinal ion transporters play important roles in fluid and electrolyte homeostasis in the intestine. We have previously shown that infection with Salmonella caused decreased colonic expression of the chloride/bicarbonate exchanger SLC26A3 (Down-Regulated in Adenoma; DRA) in a mouse model. In this study, we focused on the mechanism of DRA downregulation during Salmonella infection, by using murine epithelial enteroid-derived monolayers (EDM). The decrease in DRA expression caused by infection was recapitulated in EDM and accompanied by increased expression of ATOH1, the goblet cell marker Muc2, and the enteroendocrine cell marker ChgA. This suggested biased epithelial differentiation towards the secretory, rather than absorptive phenotype. In addition, the downstream Notch effector, Notch Intracellular Domain (NICD) and Hes1 were decreased following Salmonella infection. The relevance of Notch signaling was further investigated using a γ-secretase inhibitor, which recapitulated the downregulation in Hes1 and DRA as well as upregulation in ATOH1 and Muc2 seen following infection. Our findings suggest that Salmonella infection may result in a shift from absorptive to secretory cell types through Notch inhibition, which explains why there is a decreased capacity for absorption and ultimately the accumulation of diarrheal fluid. Our work also shows the value of EDM as a model to investigate mechanisms that might be targeted for therapy of diarrhea caused by Salmonella infection. Abstract figure legend Upon infection of the intestinal epithelium with Salmonella, diarrhea may be explained by an imbalance of intestinal epithelial differentiation. Downregulation of cell-fate commitment to the absorptive lineage, as reflected by decreased Hes1 and DRA, was observed. Conversely, upregulation of epithelial differentiation into secretory cell types was observed, as reflected by increased ATOH1, Muc2, and ChgA. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Andrew Quach
- Division of Gastroenterology, Department of Medicine, University of California San Diego, School of Medicine, La Jolla, CA, 92093, USA
| | - Rashini R Jayaratne
- Division of Gastroenterology, Department of Medicine, University of California San Diego, School of Medicine, La Jolla, CA, 92093, USA
| | - Beom Jae Lee
- Division of Gastroenterology, Department of Medicine, University of California San Diego, School of Medicine, La Jolla, CA, 92093, USA.,Department of Gastroenterology, Korea University Guro Hospital, Seoul, 08308, Republic of Korea
| | - Stella-Rita Ibeawuchi
- Department of Pathology, University of California San Diego, School of Medicine, La Jolla, CA, 92093, USA
| | - Eileen Lim
- Division of Gastroenterology, Department of Medicine, University of California San Diego, School of Medicine, La Jolla, CA, 92093, USA
| | - Soumita Das
- Department of Pathology, University of California San Diego, School of Medicine, La Jolla, CA, 92093, USA
| | - Kim E Barrett
- Division of Gastroenterology, Department of Medicine, University of California San Diego, School of Medicine, La Jolla, CA, 92093, USA.,Current affiliation: UC Davis School of Medicine, Education Building, 4610 X Street, Sacramento, CA, 95817, USA
| |
Collapse
|
7
|
Rahman MM, Afroz S, Arthur S, Sundaram U. Mast Cell Mediated Regulation of Small Intestinal Chloride Malabsorption in SAMP1/YitFc Mouse Model of Spontaneous Chronic Ileitis. Cells 2021; 10:cells10030697. [PMID: 33801010 PMCID: PMC8004028 DOI: 10.3390/cells10030697] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 03/13/2021] [Accepted: 03/18/2021] [Indexed: 12/19/2022] Open
Abstract
In Inflammatory Bowel Disease (IBD), malabsorption of electrolytes (NaCl) results in diarrhea. Inhibition of coupled NaCl absorption, mediated by the dual operation of Na:H and Cl:HCO3 exchangers on the brush border membrane (BBM) of the intestinal villus cells has been reported in IBD. In the SAMP1/YitFcs (SAMP1) mice model of spontaneous ileitis, representing Crohn’s disease, DRA (Downregulated in Adenoma) mediated Cl:HCO3 exchange was shown to be inhibited secondary to diminished affinity of the exchanger for Cl. However, NHE3 mediated Na:H exchange remained unaffected. Mast cells and their secreted mediators are known to be increased in the IBD mucosa and can affect intestinal electrolyte absorption. However, how mast cell mediators may regulate Cl:HCO3 exchange in SAMP1 mice is unknown. Therefore, the aim of this study was to determine the effect of mast cell mediators on the downregulation of DRA in SAMP1 mice. Mast cell numbers and their degranulation marker enzyme (β-hexosaminidase) levels were significantly increased in SAMP1 mice compared to control AKR mice. However, treatment of SAMP1 mice with a mast cell stabilizer, ketotifen, restored the β-hexosaminidase enzyme levels to normal in the intestine, demonstrating stabilization of mast cells by ketotifen. Moreover, downregulation of Cl:HCO3 exchange activity was restored in ketotifen treated SAMP1 mice. Kinetic studies showed that ketotifen restored the altered affinity of Cl:HCO3 exchange in SAMP1 mice villus cells thus reinstating its activity to normal. Further, RT-qPCR, Western blot and immunofluorescence studies showed that the expression levels of DRA mRNA and BBM protein, respectively remained unaltered in all experimental conditions, supporting the kinetic data. Thus, inhibition of Cl:HCO3 exchange resulting in chloride malabsorption leading to diarrhea in IBD is likely mediated by mast cell mediators.
Collapse
|
8
|
Kumar A, Priyamvada S, Ge Y, Jayawardena D, Singhal M, Anbazhagan AN, Chatterjee I, Dayal A, Patel M, Zadeh K, Saksena S, Alrefai WA, Gill RK, Zadeh M, Zhao N, Mohamadzadeh M, Dudeja PK. A Novel Role of SLC26A3 in the Maintenance of Intestinal Epithelial Barrier Integrity. Gastroenterology 2021; 160:1240-1255.e3. [PMID: 33189700 PMCID: PMC7956241 DOI: 10.1053/j.gastro.2020.11.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 11/02/2020] [Accepted: 11/03/2020] [Indexed: 02/08/2023]
Abstract
BACKGROUND & AIMS The down-regulated in adenoma (DRA) protein, encoded by SLC26A3, a key intestinal chloride anion exchanger, has recently been identified as a novel susceptibility gene for inflammatory bowel disease (IBD). However, the mechanisms underlying the increased susceptibility to inflammation induced by the loss of DRA remain elusive. Compromised barrier is a key event in IBD pathogenesis. The current studies were undertaken to elucidate the impact of DRA deficiency on epithelial barrier integrity and to define underlying mechanisms. METHODS Wild-type and DRA-knockout (KO) mice and crypt-derived colonoids were used as models for intestinal epithelial response. Paracellular permeability was measured by using fluorescein isothiocyanate-dextran flux. Immunoblotting, immunofluorescence, immunohistochemistry, and ribonucleoprotein immunoprecipitation assays were performed. Gut microbiome analysis was conducted to investigate the impact of DRA deficiency on gut microbial communities. RESULTS DRA-KO mice exhibited an increased colonic paracellular permeability with significantly decreased levels of tight junction/adherens junction proteins, including ZO-1, occludin, and E-cadherin. A similar expression pattern of occludin and E-cadherin was observed in colonoids derived from DRA-KO mice and short hairpin RNA-mediated DRA knockdown in Caco-2 cells. Microbial analysis showed gut dysbiosis in DRA-KO mice. However, cohousing studies showed that dysbiosis played only a partial role in maintaining tight junction protein expression. Furthermore, our results showed increased binding of RNA-binding protein CUGBP1 with occludin and E-cadherin genes in DRA-KO mouse colon, suggesting that posttranscriptional mechanisms play a key role in gut barrier dysfunction. CONCLUSIONS To our knowledge, our studies demonstrate a novel role of DRA in maintaining the intestinal epithelial barrier function and potential implications of its dysregulation in IBD pathogenesis.
Collapse
Affiliation(s)
- Anoop Kumar
- Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Shubha Priyamvada
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Yong Ge
- Department of Infectious Diseases and Immunology and Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, University of Florida, Gainesville, Florida
| | - Dulari Jayawardena
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Megha Singhal
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Arivarasu N Anbazhagan
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Ishita Chatterjee
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Aneal Dayal
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Mitul Patel
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Kimia Zadeh
- Department of Infectious Diseases and Immunology and Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, University of Florida, Gainesville, Florida
| | - Seema Saksena
- Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Waddah A Alrefai
- Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Ravinder K Gill
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Mojgan Zadeh
- Department of Infectious Diseases and Immunology and Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, University of Florida, Gainesville, Florida
| | - Ni Zhao
- Department of Infectious Diseases and Immunology and Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, University of Florida, Gainesville, Florida
| | - Mansour Mohamadzadeh
- Department of Infectious Diseases and Immunology and Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, University of Florida, Gainesville, Florida
| | - Pradeep K Dudeja
- Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois.
| |
Collapse
|
9
|
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.
Collapse
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
| |
Collapse
|
10
|
Kumar A, Jayawardena D, Anbazhagan AN, Chatterjee I, Priyamvada S, Alrefai WA, Borthakur A, Dudeja PK. Decreased SLC26A3 expression and function in intestinal epithelial cells in response to Cryptosporidium parvum infection. Am J Physiol Cell Physiol 2019; 317:C1205-C1212. [PMID: 31483700 DOI: 10.1152/ajpcell.00278.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The protozoan parasite Cryptosporidium parvum (CP) causes cryptosporidiosis, a diarrheal disease worldwide. Infection in immunocompetent hosts typically results in acute, self-limiting, or recurrent diarrhea. However, in immunocompromised individuals infection can cause fulminant diarrhea, extraintestinal manifestations, and death. To date, the mechanisms underlying CP-induced diarrheal pathogenesis are poorly understood. Diarrheal diseases most commonly involve increased secretion and/or decreased absorption of fluid and electrolytes. We and others have previously shown impaired chloride absorption in infectious diarrhea due to dysregulation of SLC26A3 [downregulated in adenoma (DRA)], the human intestinal apical membrane Cl-/HCO3- exchanger protein. However, there are no studies on the effects of CP infection on DRA activity. Therefore, we examined the expression and function of DRA in intestinal epithelial cells in response to CP infection in vitro and in vivo. CP infection (0.5 × 106 oocysts/well in 24-well plates, 24 h) of Caco-2 cell monolayers significantly decreased Cl-/HCO3- exchange activity (measured as DIDS-sensitive 125I uptake) as well as DRA mRNA and protein levels. Substantial downregulation of DRA mRNA and protein was also observed following CP infection ex vivo in mouse enteroid-derived monolayers and in vivo in the ileal and jejunal mucosa of C57BL/6 mice for 24 h. However, at 48 h after infection in vivo, the effects on DRA mRNA and protein were attenuated and at 5 days after infection DRA returned to normal levels. Our results suggest that impaired chloride absorption due to downregulation of DRA could be one of the contributing factors to CP-induced acute, self-limiting diarrhea in immunocompetent hosts.
Collapse
Affiliation(s)
- Anoop Kumar
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois College of Medicine, Chicago, Illinois.,Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Dulari Jayawardena
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois College of Medicine, Chicago, Illinois.,Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Arivarasu N Anbazhagan
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois College of Medicine, Chicago, Illinois.,Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Ishita Chatterjee
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois College of Medicine, Chicago, Illinois.,Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Shubha Priyamvada
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois College of Medicine, Chicago, Illinois.,Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Waddah A Alrefai
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois College of Medicine, Chicago, Illinois.,Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Alip Borthakur
- Department of Clinical and Translational Sciences, Marshall University Joan C. Edwards School of Medicine, Huntington, West Virginia
| | - Pradeep K Dudeja
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois College of Medicine, Chicago, Illinois.,Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| |
Collapse
|
11
|
Hu J, Ma L, Nie Y, Chen J, Zheng W, Wang X, Xie C, Zheng Z, Wang Z, Yang T, Shi M, Chen L, Hou Q, Niu Y, Xu X, Zhu Y, Zhang Y, Wei H, Yan X. A Microbiota-Derived Bacteriocin Targets the Host to Confer Diarrhea Resistance in Early-Weaned Piglets. Cell Host Microbe 2019; 24:817-832.e8. [PMID: 30543777 DOI: 10.1016/j.chom.2018.11.006] [Citation(s) in RCA: 164] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 09/19/2018] [Accepted: 10/23/2018] [Indexed: 12/16/2022]
Abstract
Alternatives to antibiotics for preventing diarrhea in early-weaned farm animals are sorely needed. CM piglets (a native Chinese breed) are more resistant to early-weaning stress-induced diarrhea than the commercial crossbred LY piglets. Transferring fecal microbiota, but not saline, from healthy CM into LY piglets by oral administration prior to early weaning conferred diarrhea resistance. By comparing the relative abundance of intestinal microbiota in saline and microbiota transferred LY piglets, we identified and validated Lactobacillus gasseri LA39 and Lactobacillus frumenti as two bacterial species that mediate diarrhea resistance. Diarrhea resistance depended on the bacterial secretory circular peptide gassericin A, a bacteriocin. The binding of gassericin A to Keratin 19 (KRT19) on the plasma membrane of intestinal epithelial cells was essential for enhancement of fluid absorption and decreased secretion. These findings suggest the use of L. gasseri LA39 and L. frumenti as antibiotic alternatives for preventing diarrhea in mammals.
Collapse
Affiliation(s)
- Jun Hu
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei 430070, China; Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei 430070, China
| | - Libao Ma
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei 430070, China; Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei 430070, China
| | - Yangfan Nie
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei 430070, China; Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei 430070, China
| | - Jianwei Chen
- BGI-Qingdao, BGI-Shenzhen, Qingdao 266555, China
| | - Wenyong Zheng
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei 430070, China; Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei 430070, China
| | - Xinkai Wang
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei 430070, China; Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei 430070, China
| | - Chunlin Xie
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei 430070, China; Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei 430070, China
| | - Zilong Zheng
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei 430070, China; Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei 430070, China
| | - Zhichang Wang
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei 430070, China; Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei 430070, China
| | - Tao Yang
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei 430070, China; Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei 430070, China
| | - Min Shi
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei 430070, China; Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei 430070, China
| | - Lingli Chen
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei 430070, China; Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei 430070, China
| | - Qiliang Hou
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei 430070, China; Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei 430070, China
| | - Yaorong Niu
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei 430070, China; Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei 430070, China
| | - Xiaofan Xu
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei 430070, China; Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei 430070, China
| | - Yuhua Zhu
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Yong Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang, Guizhou 550025, China
| | - Hong Wei
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Xianghua Yan
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei 430070, China; Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei 430070, China.
| |
Collapse
|
12
|
Kumar A, Chatterjee I, Anbazhagan AN, Jayawardena D, Priyamvada S, Alrefai WA, Sun J, Borthakur A, Dudeja PK. Cryptosporidium parvum disrupts intestinal epithelial barrier function via altering expression of key tight junction and adherens junction proteins. Cell Microbiol 2018; 20:e12830. [PMID: 29444370 PMCID: PMC5980709 DOI: 10.1111/cmi.12830] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 01/31/2018] [Accepted: 02/02/2018] [Indexed: 01/02/2023]
Abstract
Infection with the protozoan parasite Cryptosporidium parvum (CP) causes cryptosporidiosis, a widespread diarrhoeal disease. Impaired intestinal epithelial barrier function and increased permeability are most commonly associated with diarrhoeal diseases caused by enteric infections. However, studies on barrier disruption and underlying mechanisms in cryptosporidiosis are extremely limited. Epithelial tight junctions (TJs) and adherens junctions (AJs) are important in maintaining barrier integrity. Therefore, we examined the effects of CP infection on paracellular permeability and on the expression of the major TJ and AJ proteins utilising in vitro, ex vivo, and in vivo models. CP infection (0.5 × 106 oocysts/well in Transwell inserts, 24 hr) increased paracellular permeability (FITC-dextran flux) in Caco-2 cell monolayers and substantially decreased the protein levels of occludin, claudin 4, and E-cadherin. Claudin 3, zonula occludens-1 (ZO1) and α-catenin were also significantly decreased, whereas claudins 1 and 2 and β-catenin were not altered. Substantial downregulation of occludin, claudin 4, and E-cadherin was also observed in response to CP infection ex vivo in mouse enteroid-derived monolayers and in vivo in the ileal and jejunal mocosa of C57BL/6 mice. The mRNA levels of these proteins were also significantly decreased in CP-infected mouse ileum and jejunum but were unaltered in Caco-2 cells. Further, bafilomycin-A, an inhibitor of lysosomal proton pump, partially abrogated CP effects on occludin expression in Caco-2 cells, suggesting a potential role of posttranslational mechanisms, such as induction of protein degradation pathways, in mediating the effects of the parasite. Our studies suggest that disruption of barrier function via downregulation of specific key components of TJ and AJ could be a major mechanism underlying CP infection-induced diarrhoea.
Collapse
Affiliation(s)
- Anoop Kumar
- Division of Gastroenterology & Hepatology, Department of Medicine, UIC, and Jesse Brown VA Medical Center, Chicago IL 60612
| | - Ishita Chatterjee
- Division of Gastroenterology & Hepatology, Department of Medicine, UIC, and Jesse Brown VA Medical Center, Chicago IL 60612
| | - Arivarasu N. Anbazhagan
- Division of Gastroenterology & Hepatology, Department of Medicine, UIC, and Jesse Brown VA Medical Center, Chicago IL 60612
| | - Dulari Jayawardena
- Division of Gastroenterology & Hepatology, Department of Medicine, UIC, and Jesse Brown VA Medical Center, Chicago IL 60612
| | - Shubha Priyamvada
- Division of Gastroenterology & Hepatology, Department of Medicine, UIC, and Jesse Brown VA Medical Center, Chicago IL 60612
| | - Waddah A. Alrefai
- Division of Gastroenterology & Hepatology, Department of Medicine, UIC, and Jesse Brown VA Medical Center, Chicago IL 60612
| | - Jun Sun
- Division of Gastroenterology & Hepatology, Department of Medicine, UIC, and Jesse Brown VA Medical Center, Chicago IL 60612
| | - Alip Borthakur
- Division of Gastroenterology & Hepatology, Department of Medicine, UIC, and Jesse Brown VA Medical Center, Chicago IL 60612
| | - Pradeep K. Dudeja
- Division of Gastroenterology & Hepatology, Department of Medicine, UIC, and Jesse Brown VA Medical Center, Chicago IL 60612
| |
Collapse
|
13
|
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.
Collapse
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
| |
Collapse
|
14
|
Kumar A, Malhotra P, Coffing H, Priyamvada S, Anbazhagan AN, Krishnan HR, Gill RK, Alrefai WA, Gavin DP, Pandey SC, Dudeja PK, Saksena S. Epigenetic modulation of intestinal Na +/H + exchanger-3 expression. Am J Physiol Gastrointest Liver Physiol 2018; 314:G309-G318. [PMID: 29167115 PMCID: PMC5899241 DOI: 10.1152/ajpgi.00293.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 11/01/2017] [Accepted: 11/09/2017] [Indexed: 01/31/2023]
Abstract
Na+/H+ exchanger-3 (NHE3) is crucial for intestinal Na+ absorption, and its reduction has been implicated in infectious and inflammatory bowel diseases (IBD)-associated diarrhea. Epigenetic mechanisms such as DNA methylation are involved in the pathophysiology of IBD. Whether changes in DNA methylation are involved in modulating intestinal NHE3 gene expression is not known. Caco-2 and HuTu 80 cells were used as models of human intestinal epithelial cells. Normal C57/BL6, wild-type, or growth arrest and DNA damage-inducible 45b (GADD45b) knockout (KO) mice were used as in vivo models. NHE3 gene DNA methylation levels were assessed by MBDCap (MethyMiner) assays. Results demonstrated that in vitro methylation of NHE3 promoter construct (p-1509/+127) cloned into a cytosine guanine dinucleotide-free lucia vector decreased the promoter activity in Caco-2 cells. DNA methyltransferase inhibitor 5-azacytidine (10 μM, 24 h) caused a significant decrease in DNA methylation of the NHE3 gene and concomitantly increased NHE3 expression in Caco-2 cells. Similarly, 5-azacytidine treatment increased NHE3 mRNA levels in HuTu 80 cells. 5-Azacytidine treatment for 3 wk (10 mg/kg body wt ip, 3 times/wk) also resulted in an increase in NHE3 expression in the mouse ileum and colon. Small-interfering RNA knockdown of GADD45b (protein involved in DNA demethylation) in Caco-2 cells decreased NHE3 mRNA expression. Furthermore, there was a significant decrease in NHE3 mRNA and protein expression in the ileum and colon of GADD45b KO mice. Our findings demonstrate that NHE3 gene expression is regulated by changes in its DNA methylation. NEW & NOTEWORTHY Our studies for the first time demonstrate that Na+/H+ exchanger-3 gene expression is regulated by an epigenetic mechanism involving DNA methylation.
Collapse
Affiliation(s)
- Anoop Kumar
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Pooja Malhotra
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Hayley Coffing
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Shubha Priyamvada
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Arivarasu N Anbazhagan
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Harish R Krishnan
- Center for Alcohol Research in Epigenetics, Department of Psychiatry, University of Illinois at Chicago , Chicago, Illinois
| | - Ravinder K Gill
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Waddah A Alrefai
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
- Jesse Brown Veterans Affairs Medical Center , Chicago, Illinois
| | - David P Gavin
- Center for Alcohol Research in Epigenetics, Department of Psychiatry, University of Illinois at Chicago , Chicago, Illinois
- Jesse Brown Veterans Affairs Medical Center , Chicago, Illinois
| | - Subhash C Pandey
- Center for Alcohol Research in Epigenetics, Department of Psychiatry, University of Illinois at Chicago , Chicago, Illinois
- Jesse Brown Veterans Affairs Medical Center , Chicago, Illinois
| | - Pradeep K Dudeja
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
- Jesse Brown Veterans Affairs Medical Center , Chicago, Illinois
| | - Seema Saksena
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
- Jesse Brown Veterans Affairs Medical Center , Chicago, Illinois
| |
Collapse
|
15
|
Muthusamy S, Jeong JJ, Cheng M, Bonzo JA, Kumar A, Gonzalez FJ, Borthakur A, Dudeja PK, Saksena S, Malakooti J. Hepatocyte nuclear factor 4α regulates the expression of intestinal epithelial Na +/H + exchanger isoform 3. Am J Physiol Gastrointest Liver Physiol 2018; 314:G14-G21. [PMID: 28882825 PMCID: PMC5866373 DOI: 10.1152/ajpgi.00225.2017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 08/28/2017] [Accepted: 08/31/2017] [Indexed: 01/31/2023]
Abstract
Na+/H+ exchanger isoform 3 (NHE3) plays a key role in coupled electroneutral NaCl absorption in the mammalian intestine. Reduced NHE3 expression or function has been implicated in the pathogenesis of diarrhea associated with inflammatory bowel disease (IBD) or enteric infections. Our previous studies revealed transcriptional regulation of NHE3 by various agents such as TNF-α, IFN-γ, and butyrate involving transcription factors Sp1 and Sp3. In silico analysis revealed that the NHE3 core promoter also contains a hepatocyte nuclear factor 4α (HNF-4α) binding site that is evolutionarily conserved in several species suggesting that HNF-4α has a role in NHE3 regulation. Nhe3 mRNA levels were reduced in intestine-specific Hnf4α-null mice. However, detailed mechanisms of NHE3 regulation by HNF-4α are not known. We investigated the regulation of NHE3 gene expression by HNF-4α in vitro in the human intestinal epithelial cell line C2BBe1 and in vivo in intestine-specific Hnf4α-null ( Hnf4αΔIEpC) and control ( Hnf4αfl/fl) mice. HNF-4α knockdown by short interfering RNA in C2BBe1 cells significantly decreased NHE3 mRNA and NHE3 protein levels. Gel mobility shift and chromatin immunoprecipitation assays revealed that HNF-4α directly interacts with the HNF-4α motif in the NHE3 core promoter. Site-specific mutagenesis on the HNF-4α motif decreased, whereas ectopic overexpression of HNF-4α increased, NHE3 promoter activity. Furthermore, loss of HNF-4α in Hnf4αΔIEpC mice decreased colonic Nhe3 mRNA and NHE3 protein levels. Our results demonstrate a novel role for HNF-4α in basal regulation of NHE3 expression. These studies represent an important and novel target for therapeutic intervention in IBD-associated diarrhea. NEW & NOTEWORTHY Our studies for the first time show that hepatocyte nuclear factor 4α directly regulates NHE3 promoter activity and its basal expression in the intestine.
Collapse
Affiliation(s)
- Saminathan Muthusamy
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Jong Jin Jeong
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Ming Cheng
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Jessica A Bonzo
- Center for Cancer Research, National Cancer Institute , Bethesda, Maryland
| | - Anoop Kumar
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Frank J Gonzalez
- Center for Cancer Research, National Cancer Institute , Bethesda, Maryland
| | - Alip Borthakur
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Pradeep K Dudeja
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
- Jesse Brown Veterans Affairs Medical Center , Chicago, Illinois
| | - Seema Saksena
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
- Jesse Brown Veterans Affairs Medical Center , Chicago, Illinois
| | - Jaleh Malakooti
- Jesse Brown Veterans Affairs Medical Center , Chicago, Illinois
| |
Collapse
|
16
|
Kumar A, Chatterjee I, Gujral T, Alakkam A, Coffing H, Anbazhagan AN, Borthakur A, Saksena S, Gill RK, Alrefai WA, Dudeja PK. Activation of Nuclear Factor-κB by Tumor Necrosis Factor in Intestinal Epithelial Cells and Mouse Intestinal Epithelia Reduces Expression of the Chloride Transporter SLC26A3. Gastroenterology 2017; 153:1338-1350.e3. [PMID: 28823863 PMCID: PMC5669803 DOI: 10.1053/j.gastro.2017.08.024] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 07/26/2017] [Accepted: 08/02/2017] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Diarrhea associated with inflammatory bowel diseases has been associated with increased levels of inflammatory cytokines, including tumor necrosis factor (TNF). The intestinal mucosa of patients with inflammatory bowel diseases has reduced expression of solute carrier family 26 member 3 (SLC26A3, also called DRA). We investigated whether TNF directly affects expression of DRA in human intestinal epithelial cells (IECs) and in the intestines of mice, and studied the mechanisms of these effects. METHODS We performed quantitative reverse transcription polymerase chain reaction, immunofluorescence, and immunoblot analyses in Caco-2, HT-29, and T-84 cells human IECs cultured in 2 or 3 dimensions with or without TNF (50 ng/mL for 6-24 hours). We purified nuclear extracts and quantified nuclear factor-κB (NF-κB) activation and DNA binding. We isolated intestinal crypts from C57BL/6 mice, cultured enteroids, incubated these with TNF (50 ng/mL, 24 hours), and quantified messenger RNAs. DRA-mediated exchange of Cl- for HCO3- was measured by uptake of 125I. Expression of the NF-κB inhibitor α (IkBa) was knocked down in Caco-2 cells with small interfering RNAs. Activation of NF-κB in response to TNF was measured by luciferase reporter assays; binding of the NF-κB subunit p65 in cells was analyzed in chromatin immunoprecipitation assays. DRA promoter activity was measured in a luciferase reporter assay. C57BL/6 mice were injected with TNF (5 μg/mouse for 3-6 hours) or vehicle (control); intestines were collected and analyzed by immunofluorescence, or RNA and protein were collected from the mucosa. RESULTS Incubation of IECs with TNF reduced expression of DRA. Knockdown of NF-κB inhibitor α in IECs led to nuclear translocation of the NF-κB subunit p65 and reduced levels of DRA messenger RNA and protein. Expression of a transgene encoding p65 or p50 in IECs led to significant reductions in the promoter activity of DRA and its expression. In chromatin immunoprecipitation assays, p65 bound directly to the promoter of DRA, at the regions of -935 to -629 and -375 to -84. Injection of mice with TNF or incubation of crypt-derived enteroids with TNF reduced their expression of DRA messenger RNA and protein. CONCLUSIONS In human IECs and intestinal tissues from mice, we found TNF to activate NF-κB, which reduced expression of the Cl- / HCO3- exchanger DRA (SLC26A3), via direct binding to the promoter of DRA. This pathway is an important therapeutic target for inflammatory bowel disease-associated diarrhea.
Collapse
Affiliation(s)
- Anoop Kumar
- Division of Gastroenterology and Hepatology, University of Illinois at Chicago, Chicago, Illinois
| | - Ishita Chatterjee
- Division of Gastroenterology and Hepatology, University of Illinois at Chicago, Chicago, Illinois
| | - Tarunmeet Gujral
- Division of Gastroenterology and Hepatology, University of Illinois at Chicago, Chicago, Illinois
| | - Anas Alakkam
- Division of Gastroenterology and Hepatology, University of Illinois at Chicago, Chicago, Illinois
| | - Hayley Coffing
- Department of Microbiology and Immunology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Arivarasu N Anbazhagan
- Division of Gastroenterology and Hepatology, University of Illinois at Chicago, Chicago, Illinois
| | - Alip Borthakur
- Division of Gastroenterology and Hepatology, University of Illinois at Chicago, Chicago, Illinois
| | - Seema Saksena
- Division of Gastroenterology and Hepatology, University of Illinois at Chicago, Chicago, Illinois; Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Ravinder K Gill
- Division of Gastroenterology and Hepatology, University of Illinois at Chicago, Chicago, Illinois
| | - Waddah A Alrefai
- Division of Gastroenterology and Hepatology, University of Illinois at Chicago, Chicago, Illinois; Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Pradeep K Dudeja
- Division of Gastroenterology and Hepatology, University of Illinois at Chicago, Chicago, Illinois; Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois.
| |
Collapse
|
17
|
Chatterjee I, Kumar A, Castilla-Madrigal RM, Pellon-Cardenas O, Gill RK, Alrefai WA, Borthakur A, Verzi M, Dudeja PK. CDX2 upregulates SLC26A3 gene expression in intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol 2017; 313:G256-G264. [PMID: 28572085 PMCID: PMC5625132 DOI: 10.1152/ajpgi.00108.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/26/2017] [Accepted: 05/26/2017] [Indexed: 01/31/2023]
Abstract
SLC26A3 [downregulated in adenoma (DRA)] plays a key role in mammalian intestinal NaCl absorption, in that it mediates apical membrane Cl-/[Formula: see text] exchange. DRA function and expression are significantly decreased in diarrhea associated with inflammatory bowel disease. DRA is also considered to be a marker of cellular differentiation and is predominantly expressed in differentiated epithelial cells. Caudal-type homeobox protein-2 (CDX2) is known to regulate genes involved in intestinal epithelial differentiation and proliferation. Reduced expression of both DRA and CDX2 in intestinal inflammation prompted us to study whether the DRA gene is directly regulated by CDX2. Our initial studies utilizing CDX2 knockout (CDX2fV/fV;Cre+) mice showed a marked reduction in DRA mRNA and protein levels in proximal and distal colon. In silico analysis of the DRA promoter showed two consensus sites for CDX2 binding. Therefore, we utilized Caco-2 cells as an in vitro model to examine if DRA is a direct target of CDX2 regulation. siRNA-mediated silencing of CDX2 in Caco-2 cells resulted in a marked (~50%) decrease in DRA mRNA and protein levels, whereas ectopic overexpression of CDX2 upregulated DRA expression and also stimulated DRA promoter activity, suggesting transcriptional regulation. Electrophoretic mobility shift and chromatin immunoprecipitation assays demonstrated direct binding of CDX2 to one of the two putative CDX2 binding sites in the DRA promoter (+645/+663). In summary, our studies, for the first time, demonstrate transcriptional regulation of DRA expression by CDX2, implying that reduced expression of DRA in inflammatory bowel disease-associated diarrhea may, in part, be due to downregulation of CDX2 in the inflamed mucosa.NEW & NOTEWORTHY SLC26A3 [downregulated in adenoma (DRA)] mediates intestinal luminal NaCl absorption and is downregulated in inflammatory bowel disease-associated diarrhea. Since both DRA and caudal-type homeobox protein-2 (CDX2) are reduced in intestinal inflammation and the DRA promoter harbors CDX2 binding sites, we examined whether the DRA gene is regulated by CDX2. Our studies, for the first time, demonstrate transcriptional regulation of DRA expression by CDX2 via direct binding to the DRA promoter, suggesting that reduced expression of DRA in inflammatory bowel disease-associated diarrhea could, in part, be attributed to downregulation of CDX2.
Collapse
Affiliation(s)
- Ishita Chatterjee
- 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;
| | | | | | - Ravinder K. Gill
- 2Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois;
| | - Waddah A. Alrefai
- 1Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; ,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;
| | - Michael Verzi
- 4Department of Genetics, Rutgers University, Piscataway, New Jersey
| | - Pradeep K. Dudeja
- 1Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; ,2Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois;
| |
Collapse
|
18
|
Luo XM, Edwards MR, Reilly CM, Mu Q, Ahmed SA. Diet and Microbes in the Pathogenesis of Lupus. Lupus 2017. [DOI: 10.5772/68110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
19
|
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).
Collapse
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.
| |
Collapse
|
20
|
The role of intestinal oxalate transport in hyperoxaluria and the formation of kidney stones in animals and man. Urolithiasis 2016; 45:89-108. [PMID: 27913853 DOI: 10.1007/s00240-016-0952-z] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 11/22/2016] [Indexed: 12/26/2022]
Abstract
The intestine exerts a considerable influence over urinary oxalate in two ways, through the absorption of dietary oxalate and by serving as an adaptive extra-renal pathway for elimination of this waste metabolite. Knowledge of the mechanisms responsible for oxalate absorption and secretion by the intestine therefore have significant implications for understanding the etiology of hyperoxaluria, as well as offering potential targets for future treatment strategies for calcium oxalate kidney stone disease. In this review, we present the recent developments and advances in this area over the past 10 years, and put to the test some of the new ideas that have emerged during this time, using human and mouse models. A key focus for our discussion are the membrane-bound anion exchangers, belonging to the SLC26 gene family, some of which have been shown to participate in transcellular oxalate absorption and secretion. This has offered the opportunity to not only examine the roles of these specific transporters, revealing their importance to oxalate homeostasis, but to also probe the relative contributions made by the active transcellular and passive paracellular components of oxalate transport across the intestine. We also discuss some of the various physiological stimuli and signaling pathways which have been suggested to participate in the adaptation and regulation of intestinal oxalate transport. Finally, we offer an update on research into Oxalobacter formigenes, alongside recent investigations of other oxalate-degrading gut bacteria, in both laboratory animals and humans.
Collapse
|
21
|
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.
Collapse
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
| | | |
Collapse
|
22
|
Haileselassie Y, Navis M, Vu N, Qazi KR, Rethi B, Sverremark-Ekström E. Lactobacillus reuteri and Staphylococcus aureus differentially influence the generation of monocyte-derived dendritic cells and subsequent autologous T cell responses. IMMUNITY INFLAMMATION AND DISEASE 2016; 4:315-26. [PMID: 27621814 PMCID: PMC5004286 DOI: 10.1002/iid3.115] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 05/20/2016] [Accepted: 06/20/2016] [Indexed: 12/23/2022]
Abstract
Introduction In early‐life, the immature mucosal barrier allows contact between the gut microbiota and the developing immune system. Due to their strategic location and their ability to sample luminal antigen, dendritic cells (DC) play a central role in the interaction of microbes and immune cells in the gut. Here, we investigated how two bacteria associated with opposite immune profiles in children, that is, Lactobacillus (L.) reuteri and Staphylococcus (S.) aureus, influenced the differentiation of monocytes in vitro as well how the generated DC impacted T cell responses. Methods We exposed monocyte cultures to cell‐free supernatants (CFS) from these bacteria during their differentiation to DC. Results The presence of L. reuteri‐CFS during DC differentiation resulted in DC with a more mature phenotype, in terms of up‐regulated surface markers (HLA‐DR, CD86, CD83, CCR7) and enhanced cytokine production (IL6, IL10, and IL23), but had a reduced phagocytic capacity compared with non‐treated monocyte‐derived DC (Mo‐DC). However, upon LPS activation, L. reuteri‐CFS‐generated DC displayed a more regulated phenotype than control Mo‐DC with notable reduction of cytokine responses both at mRNA and protein levels. In contrast, S. aureus‐CFS‐generated DC were more similar to control Mo‐DC both without and after LPS stimulation, but they were still able to induce responses in autologous T cells, in the absence of further T cell stimulation. Conclusions We show that bacterial signals during DC differentiation have a profound impact on DC function and possibly also for shaping the T cell pool.
Collapse
Affiliation(s)
- Yeneneh Haileselassie
- Department of Molecular Biosciences, The Wenner-Gren Institute Stockholm University Stockholm Sweden
| | - Marit Navis
- Department of Molecular Biosciences, The Wenner-Gren Institute Stockholm University Stockholm Sweden
| | - Nam Vu
- Department of Molecular Biosciences, The Wenner-Gren Institute Stockholm University Stockholm Sweden
| | - Khaleda Rahman Qazi
- Department of Molecular Biosciences, The Wenner-Gren Institute Stockholm University Stockholm Sweden
| | - Bence Rethi
- Department of Medicine Karolinska University Hospital Stockholm Sweden
| | - Eva Sverremark-Ekström
- Department of Molecular Biosciences, The Wenner-Gren Institute Stockholm University Stockholm Sweden
| |
Collapse
|
23
|
Kravtsov DV, Ahsan MK, Kumari V, van Ijzendoorn SCD, Reyes-Mugica M, Kumar A, Gujral T, Dudeja PK, Ameen NA. Identification of intestinal ion transport defects in microvillus inclusion disease. Am J Physiol Gastrointest Liver Physiol 2016; 311:G142-55. [PMID: 27229121 PMCID: PMC4967175 DOI: 10.1152/ajpgi.00041.2016] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 05/08/2016] [Indexed: 01/31/2023]
Abstract
Loss of function mutations in the actin motor myosin Vb (Myo5b) lead to microvillus inclusion disease (MVID) and death in newborns and children. MVID results in secretory diarrhea, brush border (BB) defects, villus atrophy, and microvillus inclusions (MVIs) in enterocytes. How loss of Myo5b results in increased stool loss of chloride (Cl(-)) and sodium (Na(+)) is unknown. The present study used Myo5b loss-of-function human MVID intestine, polarized intestinal cell models of secretory crypt (T84) and villus resembling (CaCo2BBe, C2BBe) enterocytes lacking Myo5b in conjunction with immunofluorescence confocal stimulated emission depletion (gSTED) imaging, immunohistochemical staining, transmission electron microscopy, shRNA silencing, immunoblots, and electrophysiological approaches to examine the distribution, expression, and function of the major BB ion transporters NHE3 (Na(+)), CFTR (Cl(-)), and SLC26A3 (DRA) (Cl(-)/HCO3 (-)) that control intestinal fluid transport. We hypothesized that enterocyte maturation defects lead villus atrophy with immature secretory cryptlike enterocytes in the MVID epithelium. We investigated the role of Myo5b in enterocyte maturation. NHE3 and DRA localization and function were markedly reduced on the BB membrane of human MVID enterocytes and Myo5bKD C2BBe cells, while CFTR localization was preserved. Forskolin-stimulated CFTR ion transport in Myo5bKD T84 cells resembled that of control. Loss of Myo5b led to YAP1 nuclear retention, retarded enterocyte maturation, and a cryptlike phenotype. We conclude that preservation of functional CFTR in immature enterocytes, reduced functional expression of NHE3, and DRA contribute to Cl(-) and Na(+) stool loss in MVID diarrhea.
Collapse
Affiliation(s)
- Dmitri V. Kravtsov
- 1Department of Pediatrics/Gastroenterology and Hepatology, Yale School of Medicine, New Haven, Connecticut;
| | - Md Kaimul Ahsan
- 1Department of Pediatrics/Gastroenterology and Hepatology, Yale School of Medicine, New Haven, Connecticut;
| | - Vandana Kumari
- 1Department of Pediatrics/Gastroenterology and Hepatology, Yale School of Medicine, New Haven, Connecticut;
| | - Sven C. D. van Ijzendoorn
- 2Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands;
| | | | - Anoop Kumar
- 4Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; and
| | - Tarunmeet Gujral
- 4Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; and
| | - Pradeep K. Dudeja
- 4Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; and
| | - Nadia A. Ameen
- 1Department of Pediatrics/Gastroenterology and Hepatology, Yale School of Medicine, New Haven, Connecticut; ,5Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut
| |
Collapse
|
24
|
Asghar MN, Priyamvada S, Nyström JH, Anbazhagan AN, Dudeja PK, Toivola DM. Keratin 8 knockdown leads to loss of the chloride transporter DRA in the colon. Am J Physiol Gastrointest Liver Physiol 2016; 310:G1147-54. [PMID: 27125276 PMCID: PMC4935477 DOI: 10.1152/ajpgi.00354.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 04/23/2016] [Indexed: 02/06/2023]
Abstract
Keratins (K) are intermediate filament proteins important in protection from stress. The roles of keratins in the intestine are not clear, but K8 knockout (K8(-/-)) mice develop a Th2-type colonic inflammation, epithelial hyperproliferation, and mild diarrhea caused by a keratin level-dependent decrease in short-circuit current and net sodium and chloride absorption in the distal colon. The lack of K8 leads to mistargeting or altered levels of membrane proteins in colonocytes; however, the main transporter responsible for the keratin-related ion transport defect is unknown. We here analyzed protein and mRNA levels of candidate ion transporters CFTR, PAT-1, NHE-3, and DRA in ileum, cecum, and proximal and distal colon. Although no differences were observed for CFTR, PAT-1, or NHE-3, DRA mRNA levels were decreased by three- to fourfold and DRA protein was almost entirely lost in K8(-/-) cecum and proximal and distal colon compared with K8(+/+), whereas the levels in ileum were normal. In K8(+/-) mice, DRA mRNA levels were unaltered, while decreased DRA protein levels were detected in the proximal colon. Immunofluorescence staining confirmed the loss of DRA in K8(-/-) distal colon, while K8(+/-) displayed a similar but more patchy apical DRA distribution compared with K8(+/+) DRA was similarly decreased when K8 was knocked down in Caco-2 cells, confirming that K8 levels modulate DRA levels in an inflammation-independent manner. Taken together, the loss of DRA in the K8(-/-) mouse colon and cecum explains the dramatic chloride transport defect and diarrheal phenotype after K8 inactivation and identifies K8 as a novel regulator of DRA.
Collapse
Affiliation(s)
- M. Nadeem Asghar
- 1Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University and Turku Center for Disease Modeling, University of Turku, Turku, Finland; and
| | - Shubha Priyamvada
- 2University of Illinois at Chicago, Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Joel H. Nyström
- 1Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University and Turku Center for Disease Modeling, University of Turku, Turku, Finland; and
| | | | - Pradeep K. Dudeja
- 2University of Illinois at Chicago, Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Diana M. Toivola
- 1Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University and Turku Center for Disease Modeling, University of Turku, Turku, Finland; and
| |
Collapse
|
25
|
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.
Collapse
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
| |
Collapse
|
26
|
Priyamvada S, Gomes R, Gill RK, Saksena S, Alrefai WA, Dudeja PK. 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] [MESH Headings] [Grants] [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.
Collapse
Affiliation(s)
- Shubha Priyamvada
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL
| | - Rochelle Gomes
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL
| | - Ravinder K. Gill
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL
| | - Seema Saksena
- Jesse Brown VA Medical Center, University of Illinois at Chicago, Chicago, IL
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL
| | - Waddah A. Alrefai
- Jesse Brown VA Medical Center, University of Illinois at Chicago, Chicago, IL
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL
| | - Pradeep K. Dudeja
- Jesse Brown VA Medical Center, University of Illinois at Chicago, Chicago, IL
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL
| |
Collapse
|
27
|
Kumar A, Alrefai WA, Borthakur A, Dudeja PK. Lactobacillus acidophilus counteracts enteropathogenic E. coli-induced inhibition of butyrate uptake in intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol 2015; 309:G602-7. [PMID: 26272259 PMCID: PMC4593819 DOI: 10.1152/ajpgi.00186.2015] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 08/10/2015] [Indexed: 01/31/2023]
Abstract
Butyrate, a key short-chain fatty acid metabolite of colonic luminal bacterial action on dietary fiber, serves as a primary fuel for the colonocytes, ameliorates mucosal inflammation, and stimulates NaCl absorption. Absorption of butyrate into the colonocytes is essential for these intracellular effects. Monocarboxylate transporter 1 (MCT1) plays a major role in colonic luminal butyrate absorption. Previous studies (Tan J, McKenzie C, Potamitis M, Thorburn AN, Mackay CR, Macia L. Adv Immunol 121: 91-119, 2014.) showed decreased MCT1 expression and function in intestinal inflammation. We have previously shown (Borthakur A, Gill RK, Hodges K, Ramaswamy K, Hecht G, Dudeja PK. Am J Physiol Gastrointest Liver Physiol 290: G30-G35, 2006.) impaired butyrate absorption in human intestinal epithelial Caco-2 cells due to decreased MCT1 level at the apical cell surface following enteropathogenic E. coli (EPEC) infection. Current studies, therefore, examined the potential role of probiotic Lactobacilli in stimulating MCT1-mediated butyrate uptake and counteracting EPEC inhibition of MCT1 function. Of the five species of Lactobacilli, short-term (3 h) treatment with L. acidophilus (LA) significantly increased MCT1-mediated butyrate uptake in Caco-2 cells. Heat-killed LA was ineffective, whereas the conditioned culture supernatant of LA (LA-CS) was equally effective in stimulating MCT1 function, indicating that the effects are mediated by LA-secreted soluble factor(s). Furthermore, LA-CS increased apical membrane levels of MCT1 protein via decreasing its basal endocytosis, suggesting that LA-CS stimulation of butyrate uptake could be secondary to increased levels of MCT1 on the apical cell surface. LA-CS also attenuated EPEC inhibition of butyrate uptake and EPEC-mediated endocytosis of MCT1. Our studies highlight distinct role of specific LA-secreted molecules in modulating colonic butyrate absorption.
Collapse
Affiliation(s)
- Anoop Kumar
- 1Department of Medicine, Division of Gastroenterology & Hepatology, University of Illinois at Chicago, Chicago, Illinois; and
| | - Waddah A. Alrefai
- 1Department of Medicine, Division of Gastroenterology & Hepatology, University of Illinois at Chicago, Chicago, Illinois; and ,2Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Alip Borthakur
- Department of Medicine, Division of Gastroenterology & Hepatology, University of Illinois at Chicago, Chicago, Illinois; and
| | - Pradeep K. Dudeja
- 1Department of Medicine, Division of Gastroenterology & Hepatology, University of Illinois at Chicago, Chicago, Illinois; and ,2Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| |
Collapse
|