1
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Becker HM, Seidler UE. Bicarbonate secretion and acid/base sensing by the intestine. Pflugers Arch 2024; 476:593-610. [PMID: 38374228 PMCID: PMC11006743 DOI: 10.1007/s00424-024-02914-3] [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: 11/16/2023] [Revised: 01/15/2024] [Accepted: 01/17/2024] [Indexed: 02/21/2024]
Abstract
The transport of bicarbonate across the enterocyte cell membrane regulates the intracellular as well as the luminal pH and is an essential part of directional fluid movement in the gut. Since the first description of "active" transport of HCO3- ions against a concentration gradient in the 1970s, the fundamental role of HCO3- transport for multiple intestinal functions has been recognized. The ion transport proteins have been identified and molecularly characterized, and knockout mouse models have given insight into their individual role in a variety of functions. This review describes the progress made in the last decade regarding novel techniques and new findings in the molecular regulation of intestinal HCO3- transport in the different segments of the gut. We discuss human diseases with defects in intestinal HCO3- secretion and potential treatment strategies to increase luminal alkalinity. In the last part of the review, the cellular and organismal mechanisms for acid/base sensing in the intestinal tract are highlighted.
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Affiliation(s)
- Holger M Becker
- Department of Gastroenterology, Hannover Medical School, 30625, Hannover, Germany
| | - Ursula E Seidler
- Department of Gastroenterology, Hannover Medical School, 30625, Hannover, Germany.
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2
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Cheng Z, Zhou Y, Xiong X, Li L, Chen Z, Wu F, Dong R, Liu Q, Zhao Y, Jiang S, Yu Q, Chen G. Traditional herbal pair Portulacae Herba and Granati Pericarpium alleviates DSS-induced colitis in mice through IL-6/STAT3/SOCS3 pathway. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2024; 126:155283. [PMID: 38422652 DOI: 10.1016/j.phymed.2023.155283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 12/01/2023] [Accepted: 12/13/2023] [Indexed: 03/02/2024]
Abstract
BACKGROUND Portulacae Herba and Granati Pericarpium pair (PGP) is a traditional Chinese herbal medicine treatment for colitis, clinically demonstrating a relatively favorable effect on relieving diarrhea and abnormal stools. However, the underlying mechanism remain uncertain. PURPOSE The present study intends to evaluate the efficacy of PGP in treating colitis in mice and investigate its underlying mechanism. METHODS The protective effect of PGP against colitis was determined by monitoring body weight, colon length, colon weight, and survival rate in mice. Colonic inflammation was assessed by serum cytokine levels, colonic H&E staining, and local neutrophil infiltration. The reversal of intestinal epithelial barrier damage by PGP was subsequently analyzed with Western blot and histological staining. Furthermore, RNA-seq analysis and molecular docking were performed to identify potential pathways recruited by PGP. Following the hints of the transcriptomic results, the role of PGP through the IL-6/STAT3/SOCS3 pathway in DSS-induced colitis mice was verified by Western blot. RESULTS DSS-induced colitis in mice was significantly curbed by PGP treatment. PGP treatment significantly mitigated DSS-induced colitis in mice, as evidenced by improvements in body weight, DAI severity, survival rate, and inflammatory cytokines levels in serum and colon. Moreover, PGP treatment up-regulated the level of Slc26a3, thereby increasing the expressions of the tight junction/adherens junction proteins ZO-1, occludin and E-cadherin in the colon. RNA-seq analysis revealed that PGP inhibits the IL-6/STAT3/SOCS3 pathway at the transcriptional level. Molecular docking indicated that the major components of PGP could bind tightly to the proteins of IL-6 and SOCS3. Meanwhile, the result of Western blot revealed that the IL-6/STAT3/SOCS3 pathway was inhibited at the protein level after PGP administration. CONCLUSION PGP could alleviate colonic inflammation and reverse damage to the intestinal epithelial barrier in DSS-induced colitis mice. The underlying mechanism involves the inhibition of the IL-6/STAT3/SOCS3 pathway.
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Affiliation(s)
- Zhe Cheng
- Department of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yi Zhou
- Department of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xinyu Xiong
- Department of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Lingli Li
- Department of Traditional Chinese Medicine, Wuhan Fourth Hospital, Wuhan 430033, China
| | - Zekai Chen
- Department of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Fan Wu
- Department of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Ruolan Dong
- Department of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Qiong Liu
- Institute of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yan Zhao
- Department of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Shujun Jiang
- Department of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Qin Yu
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Guang Chen
- Department of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
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3
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Stepanova M, Aherne CM. Adenosine in Intestinal Epithelial Barrier Function. Cells 2024; 13:381. [PMID: 38474346 DOI: 10.3390/cells13050381] [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: 12/23/2023] [Revised: 02/13/2024] [Accepted: 02/18/2024] [Indexed: 03/14/2024] Open
Abstract
At the intestinal front, several lines of defense are in place to resist infection and injury, the mucus layer, gut microbiome and strong epithelial junctions, to name a few. Their collaboration creates a resilient barrier. In intestinal disorders, such as inflammatory bowel disease (IBD), barrier function is compromised, which results in rampant inflammation and tissue injury. In response to the destruction, the intestinal epithelium releases adenosine, a small but powerful nucleoside that functions as an alarm signal. Amidst the chaos of inflammation, adenosine aims to restore order. Within the scope of its effects is the ability to regulate intestinal epithelial barrier integrity. This review aims to define the contributions of adenosine to mucus production, microbiome-dependent barrier protection, tight junction dynamics, chloride secretion and acid-base balance to reinforce its importance in the intestinal epithelial barrier.
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Affiliation(s)
- Mariya Stepanova
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
- School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland
| | - Carol M Aherne
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
- School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland
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4
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Jayawardena D, Anbazhagan AN, Majumder A, Akram R, Nazmi A, Kaur R, Kumar A, Saksena S, Olivares-Villagómez D, Dudeja PK. Ion Transport Basis of Diarrhea, Paneth Cell Metaplasia, and Upregulation of Mechanosensory Pathway in Anti-CD40 Colitis Mice. Inflamm Bowel Dis 2024:izae002. [PMID: 38300738 DOI: 10.1093/ibd/izae002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Indexed: 02/03/2024]
Abstract
BACKGROUND Anti-Cluster of differentiation (CD)-40-induced colitis, driven by innate inflammatory responses in the intestine, is a potent animal model exhibiting IBD pathophysiology including diarrhea. However, the ion transport basis of diarrhea and some key mucosal pathways (Paneth cells, stem cell niche, and mechanosensory) in this model have not been investigated. METHODS Mucosal scrapings and intestinal tissue from control and CD40 antibody (150 µg) treated Rag2-/- mice were examined for gut inflammation, Paneth cell numbers, expression of key transporters, tight/adherens junction proteins, stem cell niche, and mechanosensory pathway via hematoxylin and eosin staining, quantitative polymerase chain reaction, and western blotting. RESULTS Compared with control, anti-CD40 antibody treatment resulted in a significant loss of body weight (P < .05) and diarrhea at day 3 postinjection. Distal colonic tissues of anti-CD40 mice exhibited increased inflammatory infiltrates, higher claudin-2 expression, and appearance of Paneth cell-like structures indicative of Paneth cell metaplasia. Significantly reduced expression (P < .005) of downregulated in adenoma (key Cl- transporter), P-glycoprotein/multidrug resistantance-1 (MDR1, xenobiotic transporter), and adherens junction protein E-cadherin (~2-fold P < .05) was also observed in the colon of anti-CD40 colitis mice. Interestingly, there were also marked alterations in the stem cell markers and upregulation of the mechanosensory YAP-TAZ pathway, suggesting the activation of alternate regeneration pathway post-tissue injury in this model. CONCLUSION Our data demonstrate that the anti-CD40 colitis model shows key features of IBD observed in the human disease, hence making it a suitable model to investigate the pathophysiology of ulcerative colitis (UC).
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Affiliation(s)
- Dulari Jayawardena
- Division of Gastroenterology and Hepatology, Dept. of Medicine, University of Illinois at Chicago, IL, USA
| | - Arivarasu N Anbazhagan
- Division of Gastroenterology and Hepatology, Dept. of Medicine, University of Illinois at Chicago, IL, USA
| | - Apurba Majumder
- Division of Gastroenterology and Hepatology, Dept. of Medicine, University of Illinois at Chicago, IL, USA
| | - Ramsha Akram
- Division of Gastroenterology and Hepatology, Dept. of Medicine, University of Illinois at Chicago, IL, USA
| | - Ali Nazmi
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Animal Sciences, The Ohio State University, Columbus, OH, USA
| | - Ramandeep Kaur
- Division of Gastroenterology and Hepatology, Dept. of Medicine, University of Illinois at Chicago, IL, USA
| | - Anoop Kumar
- Division of Gastroenterology and Hepatology, Dept. of Medicine, University of Illinois at Chicago, IL, USA
- Jesse Brown VA Medical Center, Chicago, IL, USA
| | - Seema Saksena
- Division of Gastroenterology and Hepatology, Dept. of Medicine, University of Illinois at Chicago, IL, USA
- Jesse Brown VA Medical Center, Chicago, IL, USA
| | - Danyvid Olivares-Villagómez
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Pradeep K Dudeja
- Division of Gastroenterology and Hepatology, Dept. of Medicine, University of Illinois at Chicago, IL, USA
- Jesse Brown VA Medical Center, Chicago, IL, USA
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Doi K, Mitani A, Nakakita SI, Higuchi Y, Takegawa K. Characterization of novel endo-β-N-acetylglucosaminidases from intestinal Barnesiella intestinihominis that hydrolyze multi-branched complex-type N-glycans. J Biosci Bioeng 2024; 137:101-107. [PMID: 38142217 DOI: 10.1016/j.jbiosc.2023.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 12/03/2023] [Accepted: 12/05/2023] [Indexed: 12/25/2023]
Abstract
Endo-β-N-acetylglucosaminidases (ENGases) are enzymes that hydrolyze N-linked glycans. Many ENGases have been characterized, but few have been identified with hydrolytic activity towards multi-branched complex-type N-glycans. In this study, three candidate ENGases were identified from Barnesiella intestinihominis based on database searches and phylogenetic analysis. A domain search identified the N x E motif in all three candidates, suggesting that they were members of glycosyl hydrolase family 85 (GH85). The three candidate ENGases, named Endo-BIN1, Endo-BIN2, and Endo-BIN3, were expressed in Escherichia coli cells, and their hydrolytic activity towards N-glycans and glycoproteins was measured by high performance liquid chromatography analysis and SDS-PAGE analysis. All ENGases showed hydrolytic activity towards glycoproteins, but only Endo-BIN2 and Endo-BIN3 showed hydrolytic activity towards pyridylaminated N-glycans. The optimum pH of Endo-BIN1, Endo-BIN2, and End-BIN3 was pH 6.5, 4.0, and 7.0, respectively. We measured substrate specificities of Endo-BIN2 and Endo-BIN3 towards pyridylaminated N-glycans, and found that the two Endo-BIN enzymes showed similar substrate specificity, preferring bi-antennary complex-type N-glycans with galactose or α2,6-linked sialic acid residues at the non-reducing ends. Endo-BIN2 and Endo-BIN3 were also able to hydrolyze multi-branched complex-type N-glycans. SDS-PAGE analysis revealed that all Endo-BIN enzymes were capable of releasing complex-type N-glycans from glycoproteins such as rituximab, transferrin, and fetuin. We expect that B. intestinihominis possesses ENGases to facilitate the utilization of complex-type N-glycans from host cells. These findings will have applications in N-glycan remodeling of glycoproteins and the development of pharmaceuticals.
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Affiliation(s)
- Kanako Doi
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Ai Mitani
- Fushimi Pharmaceutical Co. Ltd., Marugame, Kagawa 763-8605, Japan
| | | | - Yujiro Higuchi
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Kaoru Takegawa
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
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6
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Kim HJ, Hong JH. Multiple Regulatory Signals and Components in the Modulation of Bicarbonate Transporters. Pharmaceutics 2024; 16:78. [PMID: 38258089 PMCID: PMC10820580 DOI: 10.3390/pharmaceutics16010078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/01/2024] [Accepted: 01/03/2024] [Indexed: 01/24/2024] Open
Abstract
Bicarbonate transporters are responsible for the appropriate flux of bicarbonate across the plasma membrane to perform various fundamental cellular functions. The functions of bicarbonate transporters, including pH regulation, cell migration, and inflammation, are highlighted in various cellular systems, encompassing their participation in both physiological and pathological processes. In this review, we focused on recently identified modulatory signaling components that regulate the expression and activity of bicarbonate transporters. Moreover, we addressed recent advances in our understanding of cooperative systems of bicarbonate transporters and channelopathies. This current review aims to provide a new, in-depth understanding of numerous human diseases associated with the dysfunction of bicarbonate transporters.
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Affiliation(s)
| | - Jeong Hee Hong
- Department of Physiology, Lee Gil Ya Cancer and Diabetes Institute, College of Medicine, Gachon University, 155 Getbeolro, Yeonsu-gu, Incheon 21999, Republic of Korea;
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7
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Geertsma ER, Oliver D. SLC26 Anion Transporters. Handb Exp Pharmacol 2024; 283:319-360. [PMID: 37947907 DOI: 10.1007/164_2023_698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Solute carrier family 26 (SLC26) is a family of functionally diverse anion transporters found in all kingdoms of life. Anions transported by SLC26 proteins include chloride, bicarbonate, and sulfate, but also small organic dicarboxylates such as fumarate and oxalate. The human genome encodes ten functional homologs, several of which are causally associated with severe human diseases, highlighting their physiological importance. Here, we review novel insights into the structure and function of SLC26 proteins and summarize the physiological relevance of human members.
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Affiliation(s)
- Eric R Geertsma
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
| | - Dominik Oliver
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Philipps University Marburg, Marburg, Germany.
- Center for Mind, Brain and Behavior (CMBB), Universities of Marburg and Giessen, Marburg, Giessen, Germany.
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8
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Salari A, Xiu R, Amiri M, Pallenberg ST, Schreiber R, Dittrich AM, Tümmler B, Kunzelmann K, Seidler U. The Anion Channel TMEM16a/Ano1 Modulates CFTR Activity, but Does Not Function as an Apical Anion Channel in Colonic Epithelium from Cystic Fibrosis Patients and Healthy Individuals. Int J Mol Sci 2023; 24:14214. [PMID: 37762516 PMCID: PMC10531629 DOI: 10.3390/ijms241814214] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 09/08/2023] [Accepted: 09/11/2023] [Indexed: 09/29/2023] Open
Abstract
Studies in human colonic cell lines and murine intestine suggest the presence of a Ca2+-activated anion channel, presumably TMEM16a. Is there a potential for fluid secretion in patients with severe cystic fibrosis transmembrane conductance regulator (CFTR) mutations by activating this alternative pathway? Two-dimensional nondifferentiated colonoid-myofibroblast cocultures resembling transit amplifying/progenitor (TA/PE) cells, as well as differentiated monolayer (DM) cultures resembling near-surface cells, were established from both healthy controls (HLs) and patients with severe functional defects in the CFTR gene (PwCF). F508del mutant and CFTR knockout (null) mice ileal and colonic mucosa was also studied. HL TA/PE monolayers displayed a robust short-circuit current response (ΔIeq) to UTP (100 µM), forskolin (Fsk, 10 µM) and carbachol (CCH, 100 µM), while ΔIeq was much smaller in differentiated monolayers. The selective TMEM16a inhibitor Ani9 (up to 30 µM) did not alter the response to luminal UTP, significantly decreased Fsk-induced ΔIeq, and significantly increased CCH-induced ΔIeq in HL TA/PE colonoid monolayers. The PwCF TA/PE and the PwCF differentiated monolayers displayed negligible agonist-induced ΔIeq, without a significant effect of Ani9. When TMEM16a was localized in intracellular structures, a staining in the apical membrane was not detected. TMEM16a is highly expressed in human colonoid monolayers resembling transit amplifying cells of the colonic cryptal neck zone, from both HL and PwCF. While it may play a role in modulating agonist-induced CFTR-mediated anion currents, it is not localized in the apical membrane, and it has no function as an apical anion channel in cystic fibrosis (CF) and healthy human colonic epithelium.
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Affiliation(s)
- Azam Salari
- Department of Gastroenterology, Hannover Medical School, 30625 Hannover, Germany; (A.S.); (R.X.); (M.A.)
| | - Renjie Xiu
- Department of Gastroenterology, Hannover Medical School, 30625 Hannover, Germany; (A.S.); (R.X.); (M.A.)
| | - Mahdi Amiri
- Department of Gastroenterology, Hannover Medical School, 30625 Hannover, Germany; (A.S.); (R.X.); (M.A.)
| | - Sophia Theres Pallenberg
- Department of Pediatric Pneumonology, Allergology and Neonatology, Hannover Medical School, 30625 Hannover, Germany (A.-M.D.)
| | - Rainer Schreiber
- Institute of Physiology, University of Regensburg, 93040 Regensburg, Germany; (R.S.); (K.K.)
| | - Anna-Maria Dittrich
- Department of Pediatric Pneumonology, Allergology and Neonatology, Hannover Medical School, 30625 Hannover, Germany (A.-M.D.)
| | - Burkhard Tümmler
- Department of Pediatric Pneumonology, Allergology and Neonatology, Hannover Medical School, 30625 Hannover, Germany (A.-M.D.)
| | - Karl Kunzelmann
- Institute of Physiology, University of Regensburg, 93040 Regensburg, Germany; (R.S.); (K.K.)
| | - Ursula Seidler
- Department of Gastroenterology, Hannover Medical School, 30625 Hannover, Germany; (A.S.); (R.X.); (M.A.)
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9
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Lin C, Lin P, Lin H, Yao H, Liu S, He R, Chen H, Teng Z, Hoffman RM, Ye J, Zhu G. SLC26A3/NHERF2-IκB/NFκB/p65 feedback loop suppresses tumorigenesis and metastasis in colorectal cancer. Oncogenesis 2023; 12:41. [PMID: 37573425 PMCID: PMC10423209 DOI: 10.1038/s41389-023-00488-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 07/25/2023] [Accepted: 07/28/2023] [Indexed: 08/14/2023] Open
Abstract
Colorectal cancer (CRC) is a formidable disease due to the intricate mechanisms that drive its proliferation and metastasis. Despite significant progress in cancer research, the integration of these mechanisms that influence cancer cell behavior remains elusive. Therefore, it is imperative to comprehensively elucidate the underlying mechanisms driving CRC proliferation and metastasis. In this study, we reported a novel role of SLC26A3 in suppressing CRC progression. We found that SLC26A3 expression was downregulated in CRC, which was proportionally correlated with survival. Our in vivo and in vitro experiments demonstrated that up-regulation of SLC26A3 inhibited CRC proliferation and metastasis, while down-regulation of SLC26A3 promoted CRC progression by modulating the expression level of IκB. Furthermore, we identified NHERF2 as a novel interacting protein of SLC26A3 responsible for stabilizing the IκB protein and removing ubiquitination modification. Mechanistically, SLC26A3 augmented the interaction between NHERF2 and IκB, subsequently reducing its degradation. This process inhibited the dissociation of p65 from the IκB/p65/p50 complex and reduced the translocation of p65 from the cytoplasm to the nucleus. Moreover, our investigation revealed that NF-κB/p65 directly bound to the promoter of SLC26A3, leading to a decline in its mRNA expression. Thus, SLC26A3 impeded the nuclear translocation of NF-κB/p65, enhancing the transcription of SLC26A3 and establishing a positive regulatory feedback loop in CRC cells. Collectively, these results suggest that a SLC26A3/NHERF2-IκB/NF-κB/p65 signaling loop suppresses proliferation and metastasis in CRC cells. These findings propose a novel SLC26A3-driven signaling loop that regulates proliferation and metastasis in CRC, providing promising therapeutic interventions and prognostic targets for the management of CRC.
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Affiliation(s)
- Chunlin Lin
- Department of Gastrointestinal Surgery 2 Section, Institute of Abdominal Surgery, Key Laboratory of accurate diagnosis and treatment of cancer, The First Hospital Affiliated to Fujian Medical University, Fuzhou, 350005, China
- Key Laboratory of Ministry of Education for Gastrointestinal Cancer, Fujian Medical University, Fuzhou, 350000, China
- National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Penghang Lin
- Department of Gastrointestinal Surgery 2 Section, Institute of Abdominal Surgery, Key Laboratory of accurate diagnosis and treatment of cancer, The First Hospital Affiliated to Fujian Medical University, Fuzhou, 350005, China
- Key Laboratory of Ministry of Education for Gastrointestinal Cancer, Fujian Medical University, Fuzhou, 350000, China
| | - Huayan Lin
- Department of Gastrointestinal Surgery 2 Section, Institute of Abdominal Surgery, Key Laboratory of accurate diagnosis and treatment of cancer, The First Hospital Affiliated to Fujian Medical University, Fuzhou, 350005, China
- National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Hengxin Yao
- Department of Gastrointestinal Surgery 2 Section, Institute of Abdominal Surgery, Key Laboratory of accurate diagnosis and treatment of cancer, The First Hospital Affiliated to Fujian Medical University, Fuzhou, 350005, China
- Key Laboratory of Ministry of Education for Gastrointestinal Cancer, Fujian Medical University, Fuzhou, 350000, China
| | - Songyi Liu
- Department of Gastrointestinal Surgery 2 Section, Institute of Abdominal Surgery, Key Laboratory of accurate diagnosis and treatment of cancer, The First Hospital Affiliated to Fujian Medical University, Fuzhou, 350005, China
- Key Laboratory of Ministry of Education for Gastrointestinal Cancer, Fujian Medical University, Fuzhou, 350000, China
| | - Ruofan He
- Department of Gastrointestinal Surgery 2 Section, Institute of Abdominal Surgery, Key Laboratory of accurate diagnosis and treatment of cancer, The First Hospital Affiliated to Fujian Medical University, Fuzhou, 350005, China
- Key Laboratory of Ministry of Education for Gastrointestinal Cancer, Fujian Medical University, Fuzhou, 350000, China
| | - Hui Chen
- Department of Gastrointestinal Surgery 2 Section, Institute of Abdominal Surgery, Key Laboratory of accurate diagnosis and treatment of cancer, The First Hospital Affiliated to Fujian Medical University, Fuzhou, 350005, China
- Key Laboratory of Ministry of Education for Gastrointestinal Cancer, Fujian Medical University, Fuzhou, 350000, China
| | - Zuhong Teng
- Department of Gastrointestinal Surgery 2 Section, Institute of Abdominal Surgery, Key Laboratory of accurate diagnosis and treatment of cancer, The First Hospital Affiliated to Fujian Medical University, Fuzhou, 350005, China
- Key Laboratory of Ministry of Education for Gastrointestinal Cancer, Fujian Medical University, Fuzhou, 350000, China
| | - Robert M Hoffman
- AntiCancer, Inc, San Diego, CA, USA
- Department of Surgery, University of California, San Diego, CA, USA
| | - Jianxin Ye
- Department of Gastrointestinal Surgery 2 Section, Institute of Abdominal Surgery, Key Laboratory of accurate diagnosis and treatment of cancer, The First Hospital Affiliated to Fujian Medical University, Fuzhou, 350005, China.
- National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China.
| | - Guangwei Zhu
- Department of Gastrointestinal Surgery 2 Section, Institute of Abdominal Surgery, Key Laboratory of accurate diagnosis and treatment of cancer, The First Hospital Affiliated to Fujian Medical University, Fuzhou, 350005, China.
- National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China.
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10
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Salari A, Zhou K, Nikolovska K, Seidler U, Amiri M. Human Colonoid-Myofibroblast Coculture for Study of Apical Na +/H + Exchangers of the Lower Cryptal Neck Region. Int J Mol Sci 2023; 24:ijms24054266. [PMID: 36901695 PMCID: PMC10001859 DOI: 10.3390/ijms24054266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 02/17/2023] [Accepted: 02/18/2023] [Indexed: 02/25/2023] Open
Abstract
Cation and anion transport in the colonocyte apical membrane is highly spatially organized along the cryptal axis. Because of lack of experimental accessibility, information about the functionality of ion transporters in the colonocyte apical membrane in the lower part of the crypt is scarce. The aim of this study was to establish an in vitro model of the colonic lower crypt compartment, which expresses the transit amplifying/progenitor (TA/PE) cells, with accessibility of the apical membrane for functional study of lower crypt-expressed Na+/H+ exchangers (NHEs). Colonic crypts and myofibroblasts were isolated from human transverse colonic biopsies, expanded as three-dimensional (3D) colonoids and myofibroblast monolayers, and characterized. Filter-grown colonic myofibroblast-colonic epithelial cell (CM-CE) cocultures (myofibroblasts on the bottom of the transwell and colonocytes on the filter) were established. The expression pattern for ion transport/junctional/stem cell markers of the CM-CE monolayers was compared with that of nondifferentiated (EM) and differentiated (DM) colonoid monolayers. Fluorometric pHi measurements were performed to characterize apical NHEs. CM-CE cocultures displayed a rapid increase in transepithelial electrical resistance (TEER), paralleled by downregulation of claudin-2. They maintained proliferative activity and an expression pattern resembling TA/PE cells. The CM-CE monolayers displayed high apical Na+/H+ exchange activity, mediated to >80% by NHE2. Human colonoid-myofibroblast cocultures allow the study of ion transporters that are expressed in the apical membrane of the nondifferentiated colonocytes of the cryptal neck region. The NHE2 isoform is the predominant apical Na+/H+ exchanger in this epithelial compartment.
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Affiliation(s)
- Azam Salari
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, 30625 Hannover, Germany
| | - Kunyan Zhou
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, 30625 Hannover, Germany
- Department of Thyroid Surgery, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310027, China
| | - Katerina Nikolovska
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, 30625 Hannover, Germany
| | - Ursula Seidler
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, 30625 Hannover, Germany
- Correspondence: (U.S.); (M.A.); Tel.: +49-511-532-9427 (U.S.); Fax: +49-511-532-8428 (U.S.)
| | - Mahdi Amiri
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, 30625 Hannover, Germany
- Correspondence: (U.S.); (M.A.); Tel.: +49-511-532-9427 (U.S.); Fax: +49-511-532-8428 (U.S.)
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11
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Zhao C, Jiang Y, Yin H, Jin Z, Yuan J, Shang H, Song H. Hericium caput-medusae (Bull.: Fr.) Pers. Fermentation concentrate polysaccharide ameliorate diarrhea in DSS-induced early colitis by modulating ion channel. J Funct Foods 2023. [DOI: 10.1016/j.jff.2022.105390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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12
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The genetics of monogenic intestinal epithelial disorders. Hum Genet 2022; 142:613-654. [PMID: 36422736 PMCID: PMC10182130 DOI: 10.1007/s00439-022-02501-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 10/23/2022] [Indexed: 11/27/2022]
Abstract
Monogenic intestinal epithelial disorders, also known as congenital diarrheas and enteropathies (CoDEs), are a group of rare diseases that result from mutations in genes that primarily affect intestinal epithelial cell function. Patients with CoDE disorders generally present with infantile-onset diarrhea and poor growth, and often require intensive fluid and nutritional management. CoDE disorders can be classified into several categories that relate to broad areas of epithelial function, structure, and development. The advent of accessible and low-cost genetic sequencing has accelerated discovery in the field with over 45 different genes now associated with CoDE disorders. Despite this increasing knowledge in the causal genetics of disease, the underlying cellular pathophysiology remains incompletely understood for many disorders. Consequently, clinical management options for CoDE disorders are currently limited and there is an urgent need for new and disorder-specific therapies. In this review, we provide a general overview of CoDE disorders, including a historical perspective of the field and relationship to other monogenic disorders of the intestine. We describe the genetics, clinical presentation, and known pathophysiology for specific disorders. Lastly, we describe the major challenges relating to CoDE disorders, briefly outline key areas that need further study, and provide a perspective on the future genetic and therapeutic landscape.
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13
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Wedenoja S, Saarikivi A, Mälkönen J, Leskinen S, Lehto M, Adeshara K, Tuokkola J, Nikkonen A, Merras-Salmio L, Höyhtyä M, Hörkkö S, Haaramo A, Salonen A, de Vos WM, Korpela K, Kolho KL. Fecal microbiota in congenital chloride diarrhea and inflammatory bowel disease. PLoS One 2022; 17:e0269561. [PMID: 35679312 PMCID: PMC9182261 DOI: 10.1371/journal.pone.0269561] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 05/24/2022] [Indexed: 11/21/2022] Open
Abstract
Background and aims Subjects with congenital chloride diarrhea (CLD; a defect in solute carrier family 26 member 3 (SLC26A3)) are prone to inflammatory bowel disease (IBD). We investigated fecal microbiota in CLD and CLD-associated IBD. We also tested whether microbiota is modulated by supplementation with the short-chain fatty acid butyrate. Subjects and methods We recruited 30 patients with CLD for an observational 3-week follow-up study. Thereafter, 16 consented to oral butyrate substitution for a 3-week observational period. Fecal samples, collected once a week, were assayed for calprotectin and potential markers of inflammation, and studied by 16S ribosomal ribonucleic acid (rRNA) gene amplicon sequencing and compared to that of 19 healthy controls and 43 controls with Crohn’s disease. Data on intestinal symptoms, diet and quality of life were collected. Results Patients with CLD had increased abundances of Proteobacteria, Veillonella, and Prevotella, and lower abundances of normally dominant taxa Ruminococcaceae and Lachnospiraceae when compared with healthy controls and Crohn´s disease. No major differences in fecal microbiota were found between CLD and CLD-associated IBD (including two with yet untreated IBD). Butyrate was poorly tolerated and showed no major effects on fecal microbiota or biomarkers in CLD. Conclusions Fecal microbiota in CLD is different from that of healthy subjects or Crohn´s disease. Unexpectedly, no changes in the microbiota or fecal markers characterized CLD-associated IBD, an entity with high frequency among patients with CLD.
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Affiliation(s)
- Satu Wedenoja
- Obstetrics and Gynecology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Stem Cells and Metabolism Research Program, University of Helsinki, and Folkhälsan Research Center, Helsinki, Finland
| | - Aki Saarikivi
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Jani Mälkönen
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Saara Leskinen
- Department of Pediatrics, University of Kuopio and Kuopio University Hospital, Kuopio, Finland
| | - Markku Lehto
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, Helsinki, Finland
- Abdominal Center, Nephrology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Clinical and Molecular Metabolism, Faculty of Medicine Research Programs, University of Helsinki, Helsinki, Finland
| | - Krishna Adeshara
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, Helsinki, Finland
- Abdominal Center, Nephrology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Clinical and Molecular Metabolism, Faculty of Medicine Research Programs, University of Helsinki, Helsinki, Finland
| | - Jetta Tuokkola
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Anne Nikkonen
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Laura Merras-Salmio
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Miikka Höyhtyä
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Sohvi Hörkkö
- Medical Microbiology and Immunology, Research Unit of Biomedicine, University of Oulu, Oulu, Finland
- Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland
| | - Anu Haaramo
- Department of Otorhinolaryngology, Helsinki University Hospital, Helsinki, Finland
| | - Anne Salonen
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Willem M. de Vos
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Laboratory of Microbiology, Wageningen University, Wageningen, the Netherlands
| | - Katri Korpela
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Kaija-Leena Kolho
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- * E-mail:
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14
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Kini A, Zhao B, Basic M, Roy U, Iljazovic A, Odak I, Ye Z, Riederer B, Di Stefano G, Römermann D, Koenecke C, Bleich A, Strowig T, Seidler U. Upregulation of antimicrobial peptide expression in slc26a3-/- mice with colonic dysbiosis and barrier defect. Gut Microbes 2022; 14:2041943. [PMID: 35230892 PMCID: PMC8890434 DOI: 10.1080/19490976.2022.2041943] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Genetic defects in SLC26A3 (DRA), an intestinal Cl-/HCO3- exchanger, result in congenital chloride diarrhea (CLD), marked by lifelong acidic diarrhea and a high risk of inflammatory bowel disease. Slc26a3-/- mice serve as a model to understand the pathophysiology of CLD and search for treatment options. This study investigates the microbiota changes in slc26a3-/- colon, the genotype-related causes for the observed microbiota alterations, its inflammatory potential, as well as the corresponding host responses. The luminal and the mucosa-adherent cecal and colonic microbiota of cohoused slc26a3-/- and wt littermates were analyzed by 16S rRNA gene sequencing. Fecal microbiota transfer from cohoused slc26a3-/- and wt littermates to germ-free wt mice was performed to analyze the stability and the inflammatory potential of the communities.The cecal and colonic luminal and mucosa-adherent microbiota of slc26a3-/- mice was abnormal from an early age, with a loss of diversity, of short-chain fatty acid producers, and an increase of pathobionts. The transfer of slc26a3-/- microbiota did not result in intestinal inflammation and the microbial diversity in the recipient mice normalized over time. A strong increase in the expression of Il22, Reg3β/γ, Relmβ, and other proteins with antimicrobial functions was observed in slc26a3-/- colon from juvenile age, while the mucosal and systemic inflammatory signature was surprisingly mild. The dysbiotic microbiota, low mucosal pH, and mucus barrier defect in slc26a3-/- colon are accompanied by a stark upregulation of the expression of a panel of antimicrobial proteins. This may explain the low inflammatory burden in the gut of these mice.
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Affiliation(s)
| | - Bei Zhao
- Microbial Immune Regulation Research Group, Helmholtz Center for Infection Research, Braunschweig, Germany
| | | | - Urmi Roy
- Microbial Immune Regulation Research Group, Helmholtz Center for Infection Research, Braunschweig, Germany
| | - Aida Iljazovic
- Microbial Immune Regulation Research Group, Helmholtz Center for Infection Research, Braunschweig, Germany
| | - Ivan Odak
- Institute of Immunology Hannover Medical School Hannover, Germany
| | | | | | | | | | | | | | - Till Strowig
- Microbial Immune Regulation Research Group, Helmholtz Center for Infection Research, Braunschweig, Germany
| | - Ursula Seidler
- Department of Gastroenterology,CONTACT Ursula Seidler Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Carl Neuberg Straße 1, D30625, Hannover.de, Germany
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15
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Remigante A, Spinelli S, Pusch M, Sarikas A, Morabito R, Marino A, Dossena S. Role of SLC4 and SLC26 solute carriers during oxidative stress. Acta Physiol (Oxf) 2022; 235:e13796. [PMID: 35143116 PMCID: PMC9542443 DOI: 10.1111/apha.13796] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 02/03/2022] [Accepted: 02/07/2022] [Indexed: 12/13/2022]
Abstract
Bicarbonate is one of the major anions in mammalian tissues and fluids, is utilized by various exchangers to transport other ions and organic substrates across cell membranes and plays a critical role in cell and systemic pH homoeostasis. Chloride/bicarbonate (Cl−/HCO3−) exchangers are abundantly expressed in erythrocytes and epithelial cells and, as a consequence, are particularly exposed to oxidants in the systemic circulation and at the interface with the external environment. Here, we review the physiological functions and pathophysiological alterations of Cl−/HCO3− exchangers belonging to the solute carriers SLC4 and SLC26 superfamilies in relation to oxidative stress. Particularly well studied is the impact of oxidative stress on the red blood cell SLC4A1/AE1 (Band 3 protein), of which the function seems to be directly affected by oxidative stress and possibly involves oxidation of the transporter itself or its interacting proteins, with detrimental consequences in oxidative stress‐related diseases including inflammation, metabolic dysfunctions and ageing. The effect of oxidative stress on SLC26 members was less extensively explored. Indirect evidence suggests that SLC26 transporters can be target as well as determinants of oxidative stress, especially when their expression is abolished or dysregulated.
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Affiliation(s)
- Alessia Remigante
- Biophysics Institute National Research Council Genova Italy
- Department of Chemical Biological, Pharmaceutical and Environmental Sciences University of Messina Messina Italy
| | - Sara Spinelli
- Department of Chemical Biological, Pharmaceutical and Environmental Sciences University of Messina Messina Italy
| | - Michael Pusch
- Biophysics Institute National Research Council Genova Italy
| | - Antonio Sarikas
- Institute of Pharmacology and Toxicology Paracelsus Medical University Salzburg Austria
| | - Rossana Morabito
- Department of Chemical Biological, Pharmaceutical and Environmental Sciences University of Messina Messina Italy
| | - Angela Marino
- Department of Chemical Biological, Pharmaceutical and Environmental Sciences University of Messina Messina Italy
| | - Silvia Dossena
- Institute of Pharmacology and Toxicology Paracelsus Medical University Salzburg Austria
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16
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Kelly J, Al-Rammahi M, Daly K, Flanagan PK, Urs A, Cohen MC, di Stefano G, Bijvelds MJC, Sheppard DN, de Jonge HR, Seidler UE, Shirazi-Beechey SP. Alterations of mucosa-attached microbiome and epithelial cell numbers in the cystic fibrosis small intestine with implications for intestinal disease. Sci Rep 2022; 12:6593. [PMID: 35449374 PMCID: PMC9023491 DOI: 10.1038/s41598-022-10328-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 04/04/2022] [Indexed: 02/07/2023] Open
Abstract
Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Defective CFTR leads to accumulation of dehydrated viscous mucus within the small intestine, luminal acidification and altered intestinal motility, resulting in blockage. These changes promote gut microbial dysbiosis, adversely influencing the normal proliferation and differentiation of intestinal epithelial cells. Using Illumina 16S rRNA gene sequencing and immunohistochemistry, we assessed changes in mucosa-attached microbiome and epithelial cell profile in the small intestine of CF mice and a CF patient compared to wild-type mice and non-CF humans. We found increased abundance of pro-inflammatory Escherichia and depletion of beneficial secondary bile-acid producing bacteria in the ileal mucosa-attached microbiome of CFTR-null mice. The ileal mucosa in a CF patient was dominated by a non-aeruginosa Pseudomonas species and lacked numerous beneficial anti-inflammatory and short-chain fatty acid-producing bacteria. In the ileum of both CF mice and a CF patient, the number of absorptive enterocytes, Paneth and glucagon-like peptide 1 and 2 secreting L-type enteroendocrine cells were decreased, whereas stem and goblet cell numbers were increased. These changes in mucosa-attached microbiome and epithelial cell profile suggest that microbiota-host interactions may contribute to intestinal CF disease development with implications for therapy.
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Affiliation(s)
- Jennifer Kelly
- Department of Infection Biology and Microbiomes, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK
| | - Miran Al-Rammahi
- Department of Infection Biology and Microbiomes, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK.,Department of Physiology, Biochemistry and Pharmacology, College of Veterinary Medicine, University of Al-Qadisiyah, Al Diwaniyah, 58002, Iraq
| | - Kristian Daly
- Department of Infection Biology and Microbiomes, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK
| | - Paul K Flanagan
- Arrowe Park University Teaching Hospital NHS Trust, Wirral, CH49 5PE, UK.,Gastrointestinal and Liver Services, Aintree University Hospital, Lower Lane, Liverpool, Merseyside, L9 7AL, UK
| | - Arun Urs
- Sheffield Children's Hospital NHS Trust, Western Bank, Sheffield, S10 2TH, UK
| | - Marta C Cohen
- Histopathology Department, Sheffield Children's Hospital NHS Trust, Western Bank, Sheffield, S10 2TH, UK
| | - Gabriella di Stefano
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, 30625, Hannover, Germany
| | - Marcel J C Bijvelds
- Department of Gastroenterology and Hepatology, Erasmus MC University Medical Center, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - David N Sheppard
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, UK
| | - Hugo R de Jonge
- Department of Gastroenterology and Hepatology, Erasmus MC University Medical Center, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Ursula E Seidler
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, 30625, Hannover, Germany
| | - Soraya P Shirazi-Beechey
- Department of Infection Biology and Microbiomes, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK.
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17
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Whittamore JM, Hatch M. Oxalate Flux Across the Intestine: Contributions from Membrane Transporters. Compr Physiol 2021; 12:2835-2875. [PMID: 34964122 DOI: 10.1002/cphy.c210013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Epithelial oxalate transport is fundamental to the role occupied by the gastrointestinal (GI) tract in oxalate homeostasis. The absorption of dietary oxalate, together with its secretion into the intestine, and degradation by the gut microbiota, can all influence the excretion of this nonfunctional terminal metabolite in the urine. Knowledge of the transport mechanisms is relevant to understanding the pathophysiology of hyperoxaluria, a risk factor in kidney stone formation, for which the intestine also offers a potential means of treatment. The following discussion presents an expansive review of intestinal oxalate transport. We begin with an overview of the fate of oxalate, focusing on the sources, rates, and locations of absorption and secretion along the GI tract. We then consider the mechanisms and pathways of transport across the epithelial barrier, discussing the transcellular, and paracellular components. There is an emphasis on the membrane-bound anion transporters, in particular, those belonging to the large multifunctional Slc26 gene family, many of which are expressed throughout the GI tract, and we summarize what is currently known about their participation in oxalate transport. In the final section, we examine the physiological stimuli proposed to be involved in regulating some of these pathways, encompassing intestinal adaptations in response to chronic kidney disease, metabolic acid-base disorders, obesity, and following gastric bypass surgery. There is also an update on research into the probiotic, Oxalobacter formigenes, and the basis of its unique interaction with the gut epithelium. © 2021 American Physiological Society. Compr Physiol 11:1-41, 2021.
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Affiliation(s)
- Jonathan M Whittamore
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Marguerite Hatch
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, Florida, USA
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18
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Pathophysiological role of ion channels and transporters in gastrointestinal mucosal diseases. Cell Mol Life Sci 2021; 78:8109-8125. [PMID: 34778915 PMCID: PMC8629801 DOI: 10.1007/s00018-021-04011-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 09/10/2021] [Accepted: 10/23/2021] [Indexed: 11/13/2022]
Abstract
The incidence of gastrointestinal (GI) mucosal diseases, including various types of gastritis, ulcers, inflammatory bowel disease and GI cancer, is increasing. Therefore, it is necessary to identify new therapeutic targets. Ion channels/transporters are located on cell membranes, and tight junctions (TJs) affect acid–base balance, the mucus layer, permeability, the microbiota and mucosal blood flow, which are essential for maintaining GI mucosal integrity. As ion channel/transporter dysfunction results in various GI mucosal diseases, this review focuses on understanding the contribution of ion channels/transporters to protecting the GI mucosal barrier and the relationship between GI mucosal disease and ion channels/transporters, including Cl−/HCO3− exchangers, Cl− channels, aquaporins, Na+/H+ exchangers, and K+ channels. Here, we provide novel prospects for the treatment of GI mucosal diseases.
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19
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Norsa L, Berni Canani R, Duclaux-Loras R, Bequet E, Köglmeier J, Russell RK, Uhlig HH, Travis S, Hollis J, Koletzko S, Grimaldi G, Castaldo G, Rodrigues A, Deflandre J, Dembinski L, Shah N, Heinz-Erian P, Janecke A, Leskinen S, Wedenoja S, Koskela R, Lachaux A, Kolho KL, Ruemmele FM. Inflammatory Bowel Disease in Patients with Congenital Chloride Diarrhoea. J Crohns Colitis 2021; 15:1679-1685. [PMID: 33770165 DOI: 10.1093/ecco-jcc/jjab056] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Congenital chloride diarrhoea [CLD] is a rare autosomal recessive disease caused by mutations in the solute family carrier 26 member 3 [SLC26A3] gene. Patients suffer from life-long watery diarrhoea and chloride loss. Inflammatory bowel disease [IBD] has been reported in individual patients with CLD and in scl26a3-deficient mice. METHODS We performed an international multicentre analysis to build a CLD cohort and to identify cases with IBD. We assessed clinical and genetic characteristics of subjects and studied the cumulative incidence of CLD-associated IBD. RESULTS In a cohort of 72 patients with CLD caused by 17 different SLC26A3 mutations, we identified 12 patients [17%] diagnosed with IBD. Nine patients had Crohn's disease, two ulcerative colitis and one IBD-unclassified [IBD-U]. The prevalence of IBD in our cohort of CLD was higher than the highest prevalence of IBD in Europe [p < 0.0001]. The age of onset was variable [13.5 years, interquartile range: 8.5-23.5 years]. Patients with CLD and IBD had lower z-score for height than those without IBD. Four of 12 patients had required surgery [ileostomy formation n = 2, ileocaecal resection due to ileocaecal valve stenosis n = 1 and colectomy due to stage II transverse colon cancer n = 1]. At last follow-up, 5/12 were on biologics [adalimumab, infliximab or vedolizumab], 5/12 on immunosuppressants [azathioprine or mercaptopurine], one on 5-ASA and one off-treatment. CONCLUSIONS A substantial proportion of patients with CLD develop IBD. This suggests the potential involvement of SL26A3-mediated anion transport in IBD pathogenesis. Patients with CLD-associated IBD may require surgery for treatment failure or colon cancer.
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Affiliation(s)
- Lorenzo Norsa
- Assistance Publique - Hôpitaux de Paris, Hôpital Necker Enfants Malades, Pediatric Gastroenterology Hepatology and Nutrition, Paris, France.,Pediatric Gastroenterology Hepatology and Transplantation, ASST Papa Giovanni XXIII, Bergamo, Italy.,Université de Paris, Faculté de Médecine, Paris, France
| | - Roberto Berni Canani
- Department of Translational Medical Science - Pediatric Section, University 'Federico II', Naples, Italy.,CEINGE Advanced Biotechnologies, University Federico II, Naples, Italy.,European Laboratory for the Investigation of Food Induced Diseases, University 'Federico II', Naples, Italy
| | - Remi Duclaux-Loras
- Department of Paediatric Gastroenterology Hepatology and Nutrition, Hospices Civils de Lyon, Hôpital Femme Mère Enfant, Bron, France.,CIRI unité Inserm U1111, ENS Lyon, France
| | - Emeline Bequet
- Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, University Hospital Liège, Belgium
| | - Jutta Köglmeier
- Pediatric Gastroenterology Hepatology and Nutrition, Great Ormond Street Hospital for Sick Children, London, UK
| | - Richard K Russell
- Pediatric Gastroenterology Hepatology and Nutrition, Royal Hospital for Children, Glasgow, UK
| | - Holm H Uhlig
- Translational Gastroenterology Unit and Biomedical Research Centre, University of Oxford, Oxford, UK
| | - Simon Travis
- Translational Gastroenterology Unit and Biomedical Research Centre, University of Oxford, Oxford, UK
| | - Jennifer Hollis
- Translational Gastroenterology Unit and Biomedical Research Centre, University of Oxford, Oxford, UK
| | - Sibylle Koletzko
- Division of Gastroenterology and Hepatology, Dr. von Hauner Children's Hospital, University Hospital, LMU Munich, Munich, Germany.,Department of Paediatrics, School of Medicine Collegium Medicum University of Warmia and Mazury, Olsztyn, Poland
| | - Giusi Grimaldi
- Department of Translational Medical Science - Pediatric Section, University 'Federico II', Naples, Italy
| | - Giuseppe Castaldo
- CEINGE Advanced Biotechnologies, University Federico II, Naples, Italy
| | - Astor Rodrigues
- Translational Gastroenterology Unit and Biomedical Research Centre, University of Oxford, Oxford, UK
| | | | - Lukasz Dembinski
- Department of Paediatrics, Gastroenterology and Nutrition, Medical University of Warsaw, Warsaw, Poland
| | - Neil Shah
- Pediatric Gastroenterology Hepatology and Nutrition, Great Ormond Street Hospital for Sick Children, London, UK
| | - Peter Heinz-Erian
- Department of Pediatrics I, Medical University of Innsbruck, Innsbruck, Austria
| | - Andreas Janecke
- Department of Pediatrics I, Medical University of Innsbruck, Innsbruck, Austria
| | - Saara Leskinen
- Department of Paediatric Gastroenterology, Kuopio University Hospital, Kuopio, Finland
| | - Satu Wedenoja
- Obstetrics and Gynecology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Ritva Koskela
- Department of Internal Medicine, Oulu University Hospital, Oulu, Finland
| | - Alain Lachaux
- Department of Paediatric Gastroenterology Hepatology and Nutrition, Hospices Civils de Lyon, Hôpital Femme Mère Enfant, Bron, France
| | - Kaija-Leena Kolho
- Department of Paediatric Gastroenterology, Children's Hospital and University of Helsinki, Helsinki, Finland and Tampere University, Tampere, Finland
| | - Frank M Ruemmele
- Assistance Publique - Hôpitaux de Paris, Hôpital Necker Enfants Malades, Pediatric Gastroenterology Hepatology and Nutrition, Paris, France
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20
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Yu Q. Slc26a3 (DRA) in the Gut: Expression, Function, Regulation, Role in Infectious Diarrhea and Inflammatory Bowel Disease. Inflamm Bowel Dis 2021; 27:575-584. [PMID: 32989468 DOI: 10.1093/ibd/izaa256] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND The transport of transepithelial Cl- and HCO3- is crucial for the function of the intestinal epithelium and maintains the acid-based homeostasis. Slc26a3 (DRA), as a key chloride-bicarbonate exchanger protein in the intestinal epithelial luminal membrane, participates in the electroneutral NaCl absorption of intestine, together with Na+/H+ exchangers. Increasing recent evidence supports the essential role of decreased DRA function or expression in infectious diarrhea and inflammatory bowel disease (IBD). METHOD In this review, we give an overview of the current knowledge of Slc26a3, including its cloning and expression, function, roles in infectious diarrhea and IBD, and mechanisms of actions. A better understanding of the physiological and pathophysiological relevance of Slc26a3 in infectious diarrhea and IBD may reveal novel targets for future therapy. CONCLUSION Understanding the physiological function, regulatory interactions, and the potential mechanisms of Slc26a3 in the pathophysiology of infectious diarrhea and IBD will define novel therapeutic approaches in future.
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Affiliation(s)
- Qin Yu
- Department of Gastroenterology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan City, China
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21
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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.
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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.
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22
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Tan Q, di Stefano G, Tan X, Renjie X, Römermann D, Talbot SR, Seidler UE. Inhibition of Na + /H + exchanger isoform 3 improves gut fluidity and alkalinity in cystic fibrosis transmembrane conductance regulator-deficient and F508del mutant mice. Br J Pharmacol 2021; 178:1018-1036. [PMID: 33179259 DOI: 10.1111/bph.15323] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 11/01/2020] [Accepted: 11/02/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE Constipation and intestinal obstructive episodes are major health problems in cystic fibrosis (CF) patients. Three FDA-approved drugs against constipation-prone irritable bowel syndrome were tested for their ability to increase luminal fluidity and alkalinity in cystic fibrosis transmembrane conductance regulator (CFTR) null (cftr-/- ) and F508del mutant (F508delmut/mut ) murine intestine. EXPERIMENTAL APPROACH Guanylate cyclase C agonist linaclotide, PGE1 analogue lubiprostone and intestine-specific NHE3 inhibitor tenapanor were perfused through a ~3 cm jejunal, proximal or mid-distal colonic segment in anaesthetized cftr-/- , F508delmut/mut and WT mice. Net fluid balance was determined gravimetrically and alkaline output by pH-stat back titration. KEY RESULTS Basal jejunal fluid absorptive rates were significantly higher and basal HCO3 - output was significantly lower in cftr-/- and F508delmut/mut compared to WT mice. In cftr-/- and F508delmut/mut mice, all three drugs significantly inhibited the fluid absorptive rate and increased alkaline output in the jejunum and tenapanor and lubiprostone, but not linaclotide, in the colon. After tenapanor pre-incubation, linaclotide elicited a robust fluid secretory response in WT jejunum, while no further change in absorptive rates was observed in cftr-/- and F508delmut/mut jejunum, suggesting that the increase in gut fluidity and alkalinity by linaclotide in CF gut is mediated via NHE3 inhibition. Lubiprostone also inhibited fluid absorption in cftr-/- and F508delmut/mut jejunum via NHE3 inhibition but had a residual NHE3-independent effect. CONCLUSION AND IMPLICATIONS Linaclotide, lubiprostone and tenapanor reduced fluid absorption and increased alkaline output in the CF gut. Their application may ameliorate constipation and reduce obstructive episodes in CF patients.
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Affiliation(s)
- Qinghai Tan
- Department of Gastroenterology, Hannover Medical School, Hanover, Germany
| | | | - Xinjie Tan
- Department of Gastroenterology, Hannover Medical School, Hanover, Germany
| | - Xiu Renjie
- Department of Gastroenterology, Hannover Medical School, Hanover, Germany
| | - Dorothee Römermann
- Department of Gastroenterology, Hannover Medical School, Hanover, Germany
| | - Steven R Talbot
- Institute of Veterinary Research, Hannover Medical School, Hanover, Germany
| | - Ursula E Seidler
- Department of Gastroenterology, Hannover Medical School, Hanover, Germany
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23
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Hayashi H, Nagai H, Ohba KI, Soleimani M, Suzuki Y. Segmental differences in Slc26a3-dependent Cl - absorption and HCO 3- secretion in the mouse large intestine in vitro in Ussing chambers. J Physiol Sci 2021; 71:5. [PMID: 33514305 PMCID: PMC10717946 DOI: 10.1186/s12576-020-00784-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 11/19/2020] [Indexed: 12/12/2022]
Abstract
The anion exchanger slc26a3 (DRA), which is mutated in congenital chloride-losing diarrhea, is expressed in the apical membrane of the cecum and middle-distal colon but not in the proximal colon of rodent large intestines. To elucidate the functional roles of DRA, we measured unidirectional 36Cl- and 22Na+ fluxes and HCO3- secretion in vitro in each of these segments using DRA-KO mice. Robust Cl- absorption, which was largely abolished after DRA deficiency, was present in the cecum and middle-distal colon but absent in the proximal colon. Na+ absorption was present in all three segments in both the control and DRA-KO mice. The luminal-Cl--dependent HCO3- secretions in the cecum and middle-distal colon were abolished in the DRA-KO mice. In conclusion, DRA mediates Cl- absorption and HCO3- secretion in the mouse cecum and middle-distal colon, and may have roles in H2O absorption and luminal acid/base regulation in these segments.
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Affiliation(s)
- Hisayoshi Hayashi
- Laboratory of Physiology, School of Food and Nutritional Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan
| | - Hiroki Nagai
- Laboratory of Physiology, School of Food and Nutritional Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan
| | - Kou-Ichiro Ohba
- Laboratory of Physiology, School of Food and Nutritional Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan
| | - Manoocher Soleimani
- Department of Medicine, University of Cincinnati, Cincinnati, OH, 45267, USA
| | - Yuichi Suzuki
- Laboratory of Physiology, School of Food and Nutritional Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
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24
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Amiri M, Seidler UE, Nikolovska K. The Role of pH i in Intestinal Epithelial Proliferation-Transport Mechanisms, Regulatory Pathways, and Consequences. Front Cell Dev Biol 2021; 9:618135. [PMID: 33553180 PMCID: PMC7862550 DOI: 10.3389/fcell.2021.618135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 01/04/2021] [Indexed: 01/07/2023] Open
Abstract
During the maturation of intestinal epithelial cells along the crypt/surface axis, a multitude of acid/base transporters are differentially expressed in their apical and basolateral membranes, enabling processes of electrolyte, macromolecule, nutrient, acid/base and fluid secretion, and absorption. An intracellular pH (pHi)-gradient is generated along the epithelial crypt/surface axis, either as a consequence of the sum of the ion transport activities or as a distinctly regulated entity. While the role of pHi on proliferation, migration, and tumorigenesis has been explored in cancer cells for some time, emerging evidence suggests an important role of the pHi in the intestinal stem cells (ISCs) proliferative rate under physiological conditions. The present review highlights the current state of knowledge about the potential regulatory role of pHi on intestinal proliferation and differentiation.
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25
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Kini A, Singh AK, Riederer B, Yang I, Tan X, Stefano G, Tan Q, Xiao F, Xia W, Suerbaum S, Seidler U. Slc26a3 deletion alters pH-microclimate, mucin biosynthesis, microbiome composition and increases the TNFα expression in murine colon. Acta Physiol (Oxf) 2020; 230:e13498. [PMID: 32415725 DOI: 10.1111/apha.13498] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 05/07/2020] [Accepted: 05/08/2020] [Indexed: 12/24/2022]
Abstract
AIM SLC26A3 (DRA) mediates the absorption of luminal Cl- in exchange for HCO3 - in the distal intestine. Its expression is lost in congenital chloride diarrhoea (CLD) and strongly decreased in the presence of intestinal inflammation. To characterize the consequences of a loss of Slc26a3 beyond disturbed electrolyte transport, colonic mucus synthesis, surface accumulation and composition, pH microclimate, microbiome composition and development of inflammation was studied in slc26a3-/- mice. METHODS The epithelial surface pH microclimate and the surface mucus accumulation in vivo was assessed by two photon microscopy in exteriorized mid colon of anaesthetized slc26a3-/- and wt littermates. Mucus synthesis, composition and inflammatory markers were studied by qPCR and immunohistochemistry and microbiome composition by 16S rRNA sequencing. RESULTS Colonic pH microclimate was significantly more acidic in slc26a3-/- and to a lesser extent in cftr-/- than in wt mice. Goblet cell thecae per crypt were decreased in slc26a3-/- and increased in cftr-/- colon. Mucus accumulation in vivo was reduced, but much less so than in cftr-/- colon, which is possibly related to the different colonic fluid balance. Slc26a3-/- colonic luminal microbiome displayed strong decrease in diversity. These alterations preceded and maybe causally related to increased mucosal TNFα mRNA expression levels and leucocyte infiltration in the mid-distal colon of slc26a3-/- but not of cftr-/- mice. CONCLUSIONS These findings may explain the strong increase in the susceptibility of slc26a3-/- mice to DSS damage, and offer insight into the mechanisms leading to an increased incidence of intestinal inflammation in CLD patients.
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Affiliation(s)
- Archana Kini
- Department of GastroenterologyHannover Medical School Hannover Germany
| | - Anurag K. Singh
- Department of GastroenterologyHannover Medical School Hannover Germany
- Institute for Physiological Chemistry Martin‐Luther University Halle (Saale) Germany
| | - Brigitte Riederer
- Department of GastroenterologyHannover Medical School Hannover Germany
| | - Ines Yang
- Institute of Medical Microbiology and Hospital EpidemiologyHannover Medical School Hannover Germany
| | - Xinjie Tan
- Department of GastroenterologyHannover Medical School Hannover Germany
| | - Gabriella Stefano
- Department of GastroenterologyHannover Medical School Hannover Germany
| | - Qinghai Tan
- Department of GastroenterologyHannover Medical School Hannover Germany
| | - Fang Xiao
- Department of GastroenterologyHannover Medical School Hannover Germany
- Department of Gastroenterology Tongji HospitalHuazhou University of Technology and Science Wuhan China
| | - Weiliang Xia
- Department of GastroenterologyHannover Medical School Hannover Germany
- Department of Hepatobiliary and Transplantation Surgery First affiliated Hospital Zheijang University Hangzhou China
| | - Sebastian Suerbaum
- Institute of Medical Microbiology and Hospital EpidemiologyHannover Medical School Hannover Germany
- Faculty of Medicine Max von Pettenkofer InstituteLMU Munich Munchen Germany
| | - Ursula Seidler
- Department of GastroenterologyHannover Medical School Hannover Germany
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26
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Priyamvada S, Anbazhagan AN, Kumar A, Chatterjee I, Borthakur A, Saksena S, Gill RK, Alrefai WA, Dudeja PK. All-trans Retinoic Acid Counteracts Diarrhea and Inhibition of Downregulated in Adenoma Expression in Gut Inflammation. Inflamm Bowel Dis 2020; 26:534-545. [PMID: 31634391 PMCID: PMC7456978 DOI: 10.1093/ibd/izz249] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Indexed: 12/14/2022]
Abstract
BACKGROUND Intestinal epithelial apical membrane Cl-/HCO3- exchanger DRA (downregulated in adenoma, SLC26A3) has emerged as an important therapeutic target for diarrhea, emphasizing the potential therapeutic role of agents that upregulate DRA. All-trans retinoic acid (ATRA), a key vitamin A metabolite, was earlier shown by us to stimulate DRA expression in intestinal epithelial cells. However, its role in modulating DRA in gut inflammation has not been investigated. AIMS Our aim was to analyze the efficacy of ATRA in counteracting inflammation-induced decrease in DRA in vitro and in vivo. METHODS Interferon-γ (IFN-γ)-treated Caco-2 cells and dextran sulfate sodium (DSS)-treated C57BL/6J mice served as in vitro and in vivo models of gut inflammation, respectively. The effect of ATRA on IFN-γ-mediated inhibition of DRA function, expression, and promoter activity were elucidated. In the DSS colitis model, diarrheal phenotype, cytokine response, in vivo imaging, myeloperoxidase activity, and DRA expression were measured in the distal colon. RESULTS All-trans retinoic acid (10 μM, 24 h) abrogated IFN-γ (30 ng/mL, 24 h)-induced decrease in DRA function, expression, and promoter activity in Caco-2 cells. All-trans retinoic acid altered IFN-γ signaling via blocking IFN-γ-induced tyrosine phosphorylation of STAT-1. All-trans retinoic acid cotreatment (1 mg/kg BW, i.p. daily) of DSS-treated mice (3% in drinking water for 7 days) alleviated colitis-associated weight loss, diarrheal phenotype, and induction of IL-1β and CXCL1 and a decrease in DRA mRNA and protein levels in the colon. CONCLUSION Our data showing upregulation of DRA under normal and inflammatory conditions by ATRA demonstrate a novel role of this micronutrient in alleviating IBD-associated diarrhea.
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Affiliation(s)
- Shubha Priyamvada
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Arivarasu N Anbazhagan
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Anoop Kumar
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Ishita Chatterjee
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Alip Borthakur
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Seema Saksena
- Jesse Brown Veterans Affairs Medical Center, Chicago, IL, USA
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Ravinder K Gill
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Waddah A Alrefai
- Jesse Brown Veterans Affairs Medical Center, Chicago, IL, USA
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Pradeep K Dudeja
- Jesse Brown Veterans Affairs Medical Center, Chicago, IL, USA
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
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27
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Touré A. Importance of SLC26 Transmembrane Anion Exchangers in Sperm Post-testicular Maturation and Fertilization Potential. Front Cell Dev Biol 2019; 7:230. [PMID: 31681763 PMCID: PMC6813192 DOI: 10.3389/fcell.2019.00230] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 09/26/2019] [Indexed: 12/17/2022] Open
Abstract
In mammals, sperm cells produced within the testis are structurally differentiated but remain immotile and are unable to fertilize the oocyte unless they undergo a series of maturation events during their transit in the male and female genital tracts. This post-testicular functional maturation is known to rely on the micro-environment of both male and female genital tracts, and is tightly controlled by the pH of their luminal milieus. In particular, within the epididymis, the establishment of a low bicarbonate (HCO3–) concentration contributes to luminal acidification, which is necessary for sperm maturation and subsequent storage in a quiescent state. Following ejaculation, sperm is exposed to the basic pH of the female genital tract and bicarbonate (HCO3–), calcium (Ca2+), and chloride (Cl–) influxes induce biochemical and electrophysiological changes to the sperm cells (cytoplasmic alkalinization, increased cAMP concentration, and protein phosphorylation cascades), which are indispensable for the acquisition of fertilization potential, a process called capacitation. Solute carrier 26 (SLC26) members are conserved membranous proteins that mediate the transport of various anions across the plasma membrane of epithelial cells and constitute important regulators of pH and HCO3– concentration. Most SLC26 members were shown to physically interact and cooperate with the cystic fibrosis transmembrane conductance regulator channel (CFTR) in various epithelia, mainly by stimulating its Cl– channel activity. Among SLC26 members, the function of SLC26A3, A6, and A8 were particularly investigated in the male genital tract and the sperm cells. In this review, we will focus on SLC26s contributions to ionic- and pH-dependent processes during sperm post-testicular maturation. We will specify the current knowledge regarding their functions, based on data from the literature generated by means of in vitro and in vivo studies in knock-out mouse models together with genetic studies of infertile patients. We will also discuss the limits of those studies, the current research gaps and identify some key points for potential developments in this field.
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Affiliation(s)
- Aminata Touré
- INSERM U1016, Centre National de la Recherche Scientifique, UMR 8104, Institut Cochin, Université de Paris, Paris, France
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28
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Rao MC. Physiology of Electrolyte Transport in the Gut: Implications for Disease. Compr Physiol 2019; 9:947-1023. [PMID: 31187895 DOI: 10.1002/cphy.c180011] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We now have an increased understanding of the genetics, cell biology, and physiology of electrolyte transport processes in the mammalian intestine, due to the availability of sophisticated methodologies ranging from genome wide association studies to CRISPR-CAS technology, stem cell-derived organoids, 3D microscopy, electron cryomicroscopy, single cell RNA sequencing, transgenic methodologies, and tools to manipulate cellular processes at a molecular level. This knowledge has simultaneously underscored the complexity of biological systems and the interdependence of multiple regulatory systems. In addition to the plethora of mammalian neurohumoral factors and their cross talk, advances in pyrosequencing and metagenomic analyses have highlighted the relevance of the microbiome to intestinal regulation. This article provides an overview of our current understanding of electrolyte transport processes in the small and large intestine, their regulation in health and how dysregulation at multiple levels can result in disease. Intestinal electrolyte transport is a balance of ion secretory and ion absorptive processes, all exquisitely dependent on the basolateral Na+ /K+ ATPase; when this balance goes awry, it can result in diarrhea or in constipation. The key transporters involved in secretion are the apical membrane Cl- channels and the basolateral Na+ -K+ -2Cl- cotransporter, NKCC1 and K+ channels. Absorption chiefly involves apical membrane Na+ /H+ exchangers and Cl- /HCO3 - exchangers in the small intestine and proximal colon and Na+ channels in the distal colon. Key examples of our current understanding of infectious, inflammatory, and genetic diarrheal diseases and of constipation are provided. © 2019 American Physiological Society. Compr Physiol 9:947-1023, 2019.
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Affiliation(s)
- Mrinalini C Rao
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois, USA
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29
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Seidler U, Nikolovska K. Slc26 Family of Anion Transporters in the Gastrointestinal Tract: Expression, Function, Regulation, and Role in Disease. Compr Physiol 2019; 9:839-872. [DOI: 10.1002/cphy.c180027] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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30
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El Khouri E, Whitfield M, Stouvenel L, Kini A, Riederer B, Lores P, Roemermann D, di Stefano G, Drevet JR, Saez F, Seidler U, Touré A. Slc26a3 deficiency is associated with epididymis dysplasia and impaired sperm fertilization potential in the mouse. Mol Reprod Dev 2018; 85:682-695. [PMID: 30118583 DOI: 10.1002/mrd.23055] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 08/16/2018] [Indexed: 12/25/2022]
Abstract
Members of the solute carrier 26 (SLC26) family have emerged as important players in mediating anions fluxes across the plasma membrane of epithelial cells, in cooperation with the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel. Among them, SLC26A3 acts as a chloride/bicarbonate exchanger, highly expressed in the gastrointestinal, pancreatic and renal tissues. In humans, mutations in the SLC26A3 gene were shown to induce congenital chloride-losing diarrhea (CLD), a rare autosomal recessive disorder characterized by life-long secretory diarrhea. In view of some reports indicating subfertility in some male CLD patients together with SLC26-A3 and -A6 expression in the male genital tract and sperm cells, we analyzed the male reproductive parameters and functions of SLC26A3 deficient mice, which were previously reported to display CLD gastro-intestinal features. We show that in contrast to Slc26a6, deletion of Slc26a3 is associated with severe lesions and abnormal cytoarchitecture of the epididymis, together with sperm quantitative, morphological and functional defects, which altogether compromised male fertility. Overall, our work provides new insight into the pathophysiological mechanisms that may alter the reproductive functions and lead to male subfertility in CLD patients, with a phenotype reminiscent of that induced by CFTR deficiency in the male genital tract.
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Affiliation(s)
- Elma El Khouri
- INSERM, U1016, Institut Cochin, Departement of Development, Reproduction and Cancer, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Paris, France
| | - Marjorie Whitfield
- INSERM, U1016, Institut Cochin, Departement of Development, Reproduction and Cancer, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Paris, France.,CNRS, UMR6293, INSERM U1103, GReD, Université Clermont Auvergne, Aubière, France
| | - Laurence Stouvenel
- INSERM, U1016, Institut Cochin, Departement of Development, Reproduction and Cancer, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Paris, France
| | - Archana Kini
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany
| | - Brigitte Riederer
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany
| | - Patrick Lores
- INSERM, U1016, Institut Cochin, Departement of Development, Reproduction and Cancer, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Paris, France
| | | | | | - Joël R Drevet
- CNRS, UMR6293, INSERM U1103, GReD, Université Clermont Auvergne, Aubière, France
| | - Fabrice Saez
- CNRS, UMR6293, INSERM U1103, GReD, Université Clermont Auvergne, Aubière, France
| | - Ursula Seidler
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany
| | - Aminata Touré
- INSERM, U1016, Institut Cochin, Departement of Development, Reproduction and Cancer, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Paris, France
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31
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Association of ulcerative colitis with solute-linked carrier family 26 member A3 gene polymorphisms and its expression in colonic tissues in Chinese patients. Int J Colorectal Dis 2018; 33:1169-1172. [PMID: 29855681 DOI: 10.1007/s00384-018-3097-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/22/2018] [Indexed: 02/04/2023]
Abstract
PURPOSE Abnormalities of the solute-linked carrier family 26 member A3 (SLC26A3) are implicated in the pathogenesis of several diseases including ulcerative colitis (UC). The short communication aimed at investigating the associations of UC with SLC26A3 (rs17154444, rs7810937, rs7785539, rs2108225 and rs6951457) polymorphisms and its expression in colonic tissues. METHODS The techniques of SNaPshot method, quantitative real-time PCR and immunohistochemical analysis were conducted. RESULTS AND CONCLUSION We found that the rs2108225 variation in SLC26A3 might increase the risk of UC and affect its expression at both the mRNA and protein levels in colonic tissues of patients with UC. Moreover, the rs17154444 variation might influence the severity of UC.
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Jung D, Alshaikh A, Ratakonda S, Bashir M, Amin R, Jeon S, Stevens J, Sharma S, Ahmed W, Musch M, Hassan H. Adenosinergic signaling inhibits oxalate transport by human intestinal Caco2-BBE cells through the A 2B adenosine receptor. Am J Physiol Cell Physiol 2018; 315:C687-C698. [PMID: 30020825 DOI: 10.1152/ajpcell.00024.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Most kidney stones (KS) are composed of calcium oxalate, and small increases in urine oxalate affect the stone risk. Intestinal oxalate secretion mediated by anion exchanger SLC26A6 (PAT1) plays a crucial role in limiting net absorption of ingested oxalate, thereby preventing hyperoxaluria and related KS, reflecting the importance of understanding regulation of intestinal oxalate transport. We previously showed that ATP and UTP inhibit oxalate transport by human intestinal Caco2-BBE cells (C2). Since ATP is rapidly degraded to adenosine (ADO), we examined whether intestinal oxalate transport is regulated by ADO. We measured [14C]oxalate uptake in the presence of an outward Cl gradient as an assay of Cl-oxalate exchange activity, ≥49% of which is PAT1-mediated in C2 cells. We found that ADO significantly inhibited oxalate transport by C2 cells, an effect completely blocked by the nonselective ADO receptor antagonist 8- p-sulfophenyltheophylline. ADO also significantly inhibited oxalate efflux by C2 cells, which is important since PAT1 mediates oxalate efflux in vivo. Using pharmacological antagonists and A2B adenosine receptor (A2B AR) siRNA knockdown studies, we observed that ADO inhibits oxalate transport through the A2B AR, phospholipase C, and PKC. ADO inhibits oxalate transport by reducing PAT1 surface expression as shown by biotinylation studies. We conclude that ADO inhibits oxalate transport by lowering PAT1 surface expression in C2 cells through signaling pathways including the A2B AR, PKC, and phospholipase C. Given higher ADO levels and overexpression of the A2B AR in inflammatory bowel disease (IBD), our findings have potential relevance to pathophysiology of IBD-associated hyperoxaluria and related KS.
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Affiliation(s)
- Daniel Jung
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Altayeb Alshaikh
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | | | - Mohamed Bashir
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Ruhul Amin
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Sohee Jeon
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Jan Stevens
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Sapna Sharma
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Wahaj Ahmed
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Mark Musch
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Hatim Hassan
- Department of Medicine, The University of Chicago , Chicago, Illinois
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Lenzen H, Qian J, Manns MP, Seidler U, Jörns A. Restoration of mucosal integrity and epithelial transport function by concomitant anti-TNFα treatment in chronic DSS-induced colitis. J Mol Med (Berl) 2018; 96:831-843. [DOI: 10.1007/s00109-018-1658-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 05/27/2018] [Accepted: 06/01/2018] [Indexed: 12/25/2022]
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Abstract
Inflammatory bowel diseases broadly categorized into Crohn's disease (CD) and ulcerative colitis (UC), are chronic inflammatory disorders of the gastrointestinal tract with increasing prevalence worldwide. The etiology of the disease is complex and involves a combination of genetic, environmental, immunological and gut microbial factors. Recurring and bloody diarrhea is the most prevalent and debilitating symptom in IBD. The pathogenesis of IBD-associated diarrhea is multifactorial and is essentially an outcome of mucosal damage caused by persistent inflammation resulting in dysregulated intestinal ion transport, impaired epithelial barrier function and increased accessibility of the pathogens to the intestinal mucosa. Altered expression and/or function of epithelial ion transporters and channels is the principle cause of electrolyte retention and water accumulation in the intestinal lumen leading to diarrhea in IBD. Aberrant barrier function further contributes to diarrhea via leak-flux mechanism. Mucosal penetration of enteric pathogens promotes dysbiosis and exacerbates the underlying immune system further perpetuating IBD associated-tissue damage and diarrhea. Here, we review the mechanisms of impaired ion transport and loss of epithelial barrier function contributing to diarrhea associated with IBD.
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Affiliation(s)
- Arivarasu N Anbazhagan
- a Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago , IL , USA
| | - Shubha Priyamvada
- a Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago , IL , USA
| | - Waddah A Alrefai
- a Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago , IL , USA.,b Jesse Brown VA Medical Center , Chicago , IL , USA
| | - Pradeep K Dudeja
- a Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago , IL , USA.,b Jesse Brown VA Medical Center , Chicago , IL , USA
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SLC26A3 (DRA) prevents TNF-alpha-induced barrier dysfunction and dextran sulfate sodium-induced acute colitis. J Transl Med 2018; 98:462-476. [PMID: 29330471 DOI: 10.1038/s41374-017-0005-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 11/08/2017] [Accepted: 11/15/2017] [Indexed: 12/24/2022] Open
Abstract
SLC26A3 encodes a Cl-/HCO3- ion transporter that is also known as downregulated in adenoma (DRA) and is involved in HCO3-/mucus formation. The role of DRA in the epithelial barrier has not been previously established. In this study, we investigated the in vivo and in vitro mechanisms of DRA in the colon epithelial barrier. Immunofluorescence (IF) and co-immunoprecipitation (co-IP) studies reveal that DRA binds directly to tight junction (TJ) proteins and affects the expression of TJ proteins in polarized Caco-2BBe cells. Similarly, DRA colocalizes with ZO-1 in the intestinal epithelium. Knockdown or overexpression of DRA leads to alterations in TJ proteins and epithelial permeability. In addition, TNF-α treatment downregulates DRA by activating NF-кB and subsequently affecting intestinal epithelial barrier integrity. Furthermore, overexpression of DRA partly reverses the TNF-α-induced damage by stabilizing TJ proteins. Neutralization of TNF-α in dextran sulfate sodium (DSS)-induced colitis mice demonstrates improved the outcomes, and the therapeutic effect of the TNF-α neutralizing mAb is mediated in part by the preservation of DRA expression. These data suggest that DRA may be one of the therapeutic targets of TNF-α. Moreover, DRA delivered by adenovirus vector significantly prevents the exacerbation of colitis and improves epithelial barrier function by promoting the recovery of TJ proteins in DSS-treated mice. In conclusion, DRA plays a role in protecting the epithelial barrier and may be a therapeutic target in gut homeostasis.
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Das S, Jayaratne R, Barrett KE. The Role of Ion Transporters in the Pathophysiology of Infectious Diarrhea. Cell Mol Gastroenterol Hepatol 2018; 6:33-45. [PMID: 29928670 PMCID: PMC6007821 DOI: 10.1016/j.jcmgh.2018.02.009] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 02/26/2018] [Indexed: 12/12/2022]
Abstract
Every year, enteric infections and associated diarrhea kill millions of people. The situation is compounded by increases in the number of enteric pathogens that are acquiring resistance to antibiotics, as well as (hitherto) a relative paucity of information on host molecular targets that may contribute to diarrhea. Many forms of diarrheal disease depend on the dysregulation of intestinal ion transporters, and an associated imbalance between secretory and absorptive functions of the intestinal epithelium. A number of major transporters have been implicated in the pathogenesis of diarrheal diseases and thus an understanding of their expression, localization, and regulation after infection with various bacteria, viruses, and protozoa likely will prove critical in designing new therapies. This article surveys our understanding of transporters that are modulated by specific pathogens and the mechanism(s) involved, thereby illuminating targets that might be exploited for new therapeutic approaches.
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Key Words
- ATP, adenosine triphosphate
- ATPase, adenosine triphosphatase
- CDI, Clostridium difficile infection
- CFTR, cystic fibrosis transmembrane conductance regulator
- CLCA1, chloride channel accessory 1
- CT, cholera toxin
- CXCR2, C-X-C motif chemokine receptor 2
- DRA, down-regulated in adenoma
- Diarrhea
- ENaC, epithelial sodium channel
- EPEC, enteropathogenic Escherichia coli
- ETEC, enterotoxigenic Escherichia coli
- Enteric Pathogen
- Epithelium
- EspG, Escherichia coli secreted protein G
- GPR39, G-protein coupled receptor 39
- Ion Transport
- KCC, potassium-chloride cotransporter
- LPA, lysophosphatidic acid
- LT, heat-labile toxin
- NHE, sodium/hydrogen exchanger
- NHERF2, sodium/hydrogen exchanger regulatory factor 2
- NKCC, sodium-potassium-2 chloride cotransporter
- ORT, oral rehydration therapy
- PKC, protein kinase C
- SGLT1, sodium-glucose cotransporter 1
- SLC, solute carrier
- ST, heat-stabile toxin
- TNF, tumor necrosis factor
- Tcd, Clostridium difficile toxin
- ZnR, zinc sensing receptor
- cAMP, adenosine 3′,5′-cyclic monophosphate
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Affiliation(s)
- Soumita Das
- Department of Pathology, University of California San Diego School of Medicine, La Jolla, California
| | - Rashini Jayaratne
- Department of Medicine, University of California San Diego School of Medicine, La Jolla, California
| | - Kim E. Barrett
- Department of Medicine, University of California San Diego School of Medicine, La Jolla, California,Correspondence Address correspondence to: Kim E. Barrett, Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093-0063. fax: (858) 246-1788.
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Zhang DL, Sun YJ, Ma ML, Wang YJ, Lin H, Li RR, Liang ZL, Gao Y, Yang Z, He DF, Lin A, Mo H, Lu YJ, Li MJ, Kong W, Chung KY, Yi F, Li JY, Qin YY, Li J, Thomsen ARB, Kahsai AW, Chen ZJ, Xu ZG, Liu M, Li D, Yu X, Sun JP. Gq activity- and β-arrestin-1 scaffolding-mediated ADGRG2/CFTR coupling are required for male fertility. eLife 2018; 7:e33432. [PMID: 29393851 PMCID: PMC5839696 DOI: 10.7554/elife.33432] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 01/30/2018] [Indexed: 12/23/2022] Open
Abstract
Luminal fluid reabsorption plays a fundamental role in male fertility. We demonstrated that the ubiquitous GPCR signaling proteins Gq and β-arrestin-1 are essential for fluid reabsorption because they mediate coupling between an orphan receptor ADGRG2 (GPR64) and the ion channel CFTR. A reduction in protein level or deficiency of ADGRG2, Gq or β-arrestin-1 in a mouse model led to an imbalance in pH homeostasis in the efferent ductules due to decreased constitutive CFTR currents. Efferent ductule dysfunction was rescued by the specific activation of another GPCR, AGTR2. Further mechanistic analysis revealed that β-arrestin-1 acts as a scaffold for ADGRG2/CFTR complex formation in apical membranes, whereas specific residues of ADGRG2 confer coupling specificity for different G protein subtypes, this specificity is critical for male fertility. Therefore, manipulation of the signaling components of the ADGRG2-Gq/β-arrestin-1/CFTR complex by small molecules may be an effective therapeutic strategy for male infertility.
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Affiliation(s)
- Dao-Lai Zhang
- Key Laboratory Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular BiologyShandong University School of MedicineJinanChina
- Department of PhysiologyShandong University School of MedicineJinanChina
- School of PharmacyBinzhou Medical UniversityYantaiChina
| | - Yu-Jing Sun
- Key Laboratory Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular BiologyShandong University School of MedicineJinanChina
- Department of PhysiologyShandong University School of MedicineJinanChina
| | - Ming-Liang Ma
- Key Laboratory Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular BiologyShandong University School of MedicineJinanChina
- Department of PhysiologyShandong University School of MedicineJinanChina
| | - Yi-jing Wang
- Key Laboratory Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular BiologyShandong University School of MedicineJinanChina
- Department of PhysiologyShandong University School of MedicineJinanChina
| | - Hui Lin
- Key Laboratory Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular BiologyShandong University School of MedicineJinanChina
- Department of PhysiologyShandong University School of MedicineJinanChina
| | - Rui-Rui Li
- Key Laboratory Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular BiologyShandong University School of MedicineJinanChina
- Department of PhysiologyShandong University School of MedicineJinanChina
| | - Zong-Lai Liang
- Key Laboratory Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular BiologyShandong University School of MedicineJinanChina
- Department of PhysiologyShandong University School of MedicineJinanChina
| | - Yuan Gao
- Key Laboratory Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular BiologyShandong University School of MedicineJinanChina
- Department of PhysiologyShandong University School of MedicineJinanChina
| | - Zhao Yang
- Key Laboratory Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular BiologyShandong University School of MedicineJinanChina
- Department of PhysiologyShandong University School of MedicineJinanChina
| | - Dong-Fang He
- Key Laboratory Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular BiologyShandong University School of MedicineJinanChina
- Department of PhysiologyShandong University School of MedicineJinanChina
| | - Amy Lin
- Department of BiochemistrySchool of Medicine, Duke UniversityDurhamUnited States
| | - Hui Mo
- Key Laboratory Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular BiologyShandong University School of MedicineJinanChina
- Department of PhysiologyShandong University School of MedicineJinanChina
| | - Yu-Jing Lu
- Key Laboratory Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular BiologyShandong University School of MedicineJinanChina
- Department of PhysiologyShandong University School of MedicineJinanChina
| | - Meng-Jing Li
- Key Laboratory Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular BiologyShandong University School of MedicineJinanChina
- Department of PhysiologyShandong University School of MedicineJinanChina
| | - Wei Kong
- Key Laboratory of Molecular Cardiovascular Science, Department of Physiology and PathophysiologySchool of Basic Medical Sciences, Peking UniversityBeijingChina
| | | | - Fan Yi
- Department of PharmacologyShandong University School of MedicineJinanChina
| | - Jian-Yuan Li
- Key Laboratory of Male Reproductive Health, National Research Institute for Family PlanningNational Health and Family Planning CommissionBeijingChina
| | - Ying-Ying Qin
- National Research Center for Assisted Reproductive Technology and Reproductive GeneticsShandong UniversityJinanChina
| | - Jingxin Li
- Department of PhysiologyShandong University School of MedicineJinanChina
| | - Alex R B Thomsen
- Department of BiochemistrySchool of Medicine, Duke UniversityDurhamUnited States
| | - Alem W Kahsai
- Department of BiochemistrySchool of Medicine, Duke UniversityDurhamUnited States
| | - Zi-Jiang Chen
- National Research Center for Assisted Reproductive Technology and Reproductive GeneticsShandong UniversityJinanChina
| | - Zhi-Gang Xu
- Shandong Provincial Key Laboratory of Animal Cells and Developmental BiologyShandong University School of Life SciencesJinanChina
| | - Mingyao Liu
- Shanghai Key Laboratory of Regulatory Biology, School of Life SciencesInstitute of Biomedical Sciences, East China Normal UniversityShanghaiChina
- Department of Molecular and Cellular Medicine, Institute of Biosciences and TechnologyTexas A&M University Health Science CenterHoustonUnited States
| | - Dali Li
- Shanghai Key Laboratory of Regulatory Biology, School of Life SciencesInstitute of Biomedical Sciences, East China Normal UniversityShanghaiChina
| | - Xiao Yu
- Department of PhysiologyShandong University School of MedicineJinanChina
| | - Jin-Peng Sun
- Key Laboratory Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular BiologyShandong University School of MedicineJinanChina
- Department of BiochemistrySchool of Medicine, Duke UniversityDurhamUnited States
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Ding X, Li D, Li M, Tian D, Yu H, Yu Q. Tumor necrosis factor-α acts reciprocally with solute carrier family 26, member 3, (downregulated-in-adenoma) and reduces its expression, leading to intestinal inflammation. Int J Mol Med 2017; 41:1224-1232. [PMID: 29286110 PMCID: PMC5819926 DOI: 10.3892/ijmm.2017.3347] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 12/18/2017] [Indexed: 12/12/2022] Open
Abstract
Solute carrier family 26, member 3 (Slc26a3), also termed downregulated-in-adenoma (DRA) is a member of the Slc26 family of anion transporters and is mutated in congenital chloride diarrhea. Our previous study demonstrated that DRA deficiency is associated with severely reduced colonic HCO3‑ secretion, a loss of colonic fluid absorption, a lack of a firmly adherent mucus layer and a severely reduced colonic mucosal resistance to dextran sodium sulfate (DSS) damage. However, the direct effect of mediators that trigger intestinal inflammatory factors on DRA has not been fully investigated. Tumor necrosis factor (TNF)‑α is a central mediator of intestinal inflammation in inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease. However, to the best of our knowledge, whether TNF‑α acts reciprocally with DRA leading to the development of gut inflammation in IBD has not been reported. The present study identified that the expression level of DRA was reduced in active UC patients and DSS‑induced colitis mice with high expression levels of TNF‑α identified in the peripheral blood serum. In addition, TNF‑α may affect the expression level of DRA in human colonic Caco2BBE cells in a dose‑dependent manner, including in DRA overexpressed Caco2BBE cells. Furthermore, knockdown of TNF‑α in Caco2BBE cells led to a higher expression level of DRA and a markedly reduced secretion of TNF‑α in the culture media. In addition, knockdown of DRA in Caco2BBE cells led to a higher secretion of TNF‑α in the culture media compared with the control cells, which could be reversed by overexpression of DRA. Overall, these results indicate that TNF‑α may act reciprocally with DRA, leading to the development of intestinal inflammation. Based on the pivotal position of TNF‑α in IBD, DRA is hypothesized to have therapeutic potential against colitis serving as an important target.
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Affiliation(s)
- Xiangming Ding
- Department of Gastroenterology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Dongxiao Li
- Department of Gastroenterology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Mengke Li
- Department of Gastroenterology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Dean Tian
- Department of Gastroenterology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Hongbing Yu
- Department of Pediatrics, BC Children's Hospital and The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Qin Yu
- Department of Gastroenterology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
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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.
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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.
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40
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Chao PC, Butt AG. cAMP-dependent secretagogues stimulate the NaHCO 3 cotransporter in the villous epithelium of the brushtail possum, Trichosurus vulpecula. J Comp Physiol B 2017; 187:1019-1028. [PMID: 28247055 DOI: 10.1007/s00360-017-1063-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 01/30/2017] [Accepted: 02/05/2017] [Indexed: 12/22/2022]
Abstract
In the ileum of the brushtail possum, Trichosurus vulpecula, fluid secretion appears to be driven by electrogenic HCO3- secretion. Consistent with this, the cystic fibrosis transmembrane conductance regulator is expressed in the apical membrane of the ileal epithelial cells and the pancreatic or secretory variant of the NaHCO3 cotransporter in the basolateral membrane. This suggests that in the possum ileum, electrogenic HCO3- secretion is driven by basolateral NaHCO3 cotransporter (NBC) activity. To determine if the NBC contributes to HCO3- secretion in the possum ileum, intracellular pH (pHi) measurements in isolated villi were used to demonstrate NBC activity in the ileal epithelial cells and investigate the effect of cAMP-dependent secretagogues. In CO2/HCO3--free solutions, recovery of the epithelial cells from an acid load was Na+-dependent and ≈80% inhibited by ethyl-isopropyl-amiloride (EIPA, 10 µmol L-1), indicative of the presence of an Na+/H+ exchanger, most likely NHE1. However, in the presence of CO2/HCO3-, EIPA only inhibited ≈ 50% of the recovery, the remainder was inhibited by 4,4'-diisothiocyano-2,2'-stilbenedisulfonic acid (DIDS, 500 µmol L-1), indicative of NBC activity. Under steady-state conditions, NHE1 inhibition by EIPA had little effect on pHi in the presence or absence of secretagogues, but NBC inhibition with DIDS resulted in a rapid acidification of the cells, which was increased fivefold by secretagogues. These data demonstrate the functional activity of an NaHCO3 cotransporter in the ileal epithelial cells. Furthermore, the stimulation of NBC activity by secretagogues is consistent with the involvement of an NaHCO3 cotransporter in electrogenic HCO3- secretion.
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Affiliation(s)
- Pin-Chun Chao
- Department of Physiology, School of Biomedical Sciences, University of Otago, PO Box 56, Dunedin, 9054, New Zealand
| | - A Grant Butt
- Department of Physiology, School of Biomedical Sciences, University of Otago, PO Box 56, Dunedin, 9054, New Zealand.
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41
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42
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Tang L, Cheng CY, Sun X, Pedicone AJ, Mohamadzadeh M, Cheng SX. The Extracellular Calcium-Sensing Receptor in the Intestine: Evidence for Regulation of Colonic Absorption, Secretion, Motility, and Immunity. Front Physiol 2016; 7:245. [PMID: 27458380 PMCID: PMC4914593 DOI: 10.3389/fphys.2016.00245] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Accepted: 06/03/2016] [Indexed: 12/14/2022] Open
Abstract
Different from other epithelia, the intestinal epithelium has the complex task of providing a barrier impeding the entry of toxins, food antigens, and microbes, while at the same time allowing for the transfer of nutrients, electrolytes, water, and microbial metabolites. These molecules/organisms are transported either transcellularly, crossing the apical and basolateral membranes of enterocytes, or paracellularly, passing through the space between enterocytes. Accordingly, the intestinal epithelium can affect energy metabolism, fluid balance, as well as immune response and tolerance. To help accomplish these complex tasks, the intestinal epithelium has evolved many sensing receptor mechanisms. Yet, their roles and functions are only now beginning to be elucidated. This article explores one such sensing receptor mechanism, carried out by the extracellular calcium-sensing receptor (CaSR). In addition to its established function as a nutrient sensor, coordinating food digestion, nutrient absorption, and regulating energy metabolism, we present evidence for the emerging role of CaSR in the control of intestinal fluid homeostasis and immune balance. An additional role in the modulation of the enteric nerve activity and motility is also discussed. Clearly, CaSR has profound effects on many aspects of intestinal function. Nevertheless, more work is needed to fully understand all functions of CaSR in the intestine, including detailed mechanisms of action and specific pathways involved. Considering the essential roles CaSR plays in gastrointestinal physiology and immunology, research may lead to a translational opportunity for the development of novel therapies that are based on CaSR's unique property of using simple nutrients such as calcium, polyamines, and certain amino acids/oligopeptides as activators. It is possible that, through targeting of intestinal CaSR with a combination of specific nutrients, oral solutions that are both inexpensive and practical may be developed to help in conditioning the gut microenvironment and in maintaining digestive health.
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Affiliation(s)
- Lieqi Tang
- Department of Pediatrics, Gastroenterology, Hepatology, and Nutrition, University of Florida Gainesville, FL, USA
| | - Catherine Y Cheng
- Department of Pediatrics, Gastroenterology, Hepatology, and Nutrition, University of Florida Gainesville, FL, USA
| | - Xiangrong Sun
- Department of Pediatrics, Gastroenterology, Hepatology, and Nutrition, University of Florida Gainesville, FL, USA
| | - Alexandra J Pedicone
- Department of Pediatrics, Gastroenterology, Hepatology, and Nutrition, University of Florida Gainesville, FL, USA
| | - Mansour Mohamadzadeh
- Department of Medicine, Center for Inflammation and Mucosal Immunology, University of Florida Gainesville, FL, USA
| | - Sam X Cheng
- Department of Pediatrics, Gastroenterology, Hepatology, and Nutrition, University of Florida Gainesville, FL, USA
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43
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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.
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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
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44
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Yu Q, Liu X, Liu Y, Riederer B, Li T, Tian DA, Tuo B, Shull G, Seidler U. Defective small intestinal anion secretion, dipeptide absorption, and intestinal failure in suckling NBCe1-deficient mice. Pflugers Arch 2016; 468:1419-32. [PMID: 27228994 PMCID: PMC4951514 DOI: 10.1007/s00424-016-1836-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 05/05/2016] [Accepted: 05/09/2016] [Indexed: 11/27/2022]
Abstract
The electrogenic Na+HCO3− cotransporter NBCe1 (Slc4a4) is strongly expressed in the basolateral enterocyte membrane in a villous/surface predominant fashion. In order to better understand its physiological function in the intestine, isolated mucosae in miniaturized Ussing chambers and microdissected intestinal villi or crypts loaded with the fluorescent pH-indicator BCECF were studied from the duodenum, jejunum, and colon of 14- to 17-days-old slc4a4-deficient (KO) and WT mice. NBCe1 was active in the basal state in all intestinal segments under study, most likely to compensate for acid loads imposed upon the enterocytes. Upregulation of other basolateral base uptake mechanism occurs, but in a segment-specific fashion. Loss of NBCe1 resulted in severely impaired Cl− and fluid secretory response, but not HCO3− secretory response to agonist stimulation. In addition, NBCe1 was found to be active during transport processes that load the surface enterocytes with acid, such as Slc26a3 (DRA)-mediated luminal Cl−/HCO3− exchange or PEPT1-mediated H+/dipeptide uptake. Possibly because of the high energy demand for hyperventilation in conjunction with the fluid secretory and nutrient absorptive defects and the relative scarcity of compensatory mechanisms, NBCe1-deficient mice developed progressive jejunal failure, worsening of metabolic acidosis, and death in the third week of life. Our data suggest that the electrogenic influx of base via NBCe1 maintains enterocyte anion homeostasis and pHi control. Its loss impairs small intestinal Cl− and fluid secretion as well as the neutralization of acid loads imposed on the enterocytes during nutrient and electrolyte absorption.
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Affiliation(s)
- Qin Yu
- Department of Gastroenterology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.,Department of Gastroenterology, Tongji Hospital, Huazhong University of Science & Technology, Wuhan, People's Republic of China
| | - Xuemei Liu
- Department of Gastroenterology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.,Department of Gastroenterology, Zunyi Medical College, Zunyi, China
| | - Yongjian Liu
- Department of Gastroenterology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Brigitte Riederer
- Department of Gastroenterology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Taolang Li
- Department of Gastroenterology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.,Department of Gastrointestinal Surgery, Zunyi Medical College, Zunyi, China
| | - De-An Tian
- Department of Gastroenterology, Tongji Hospital, Huazhong University of Science & Technology, Wuhan, People's Republic of China
| | - Biguang Tuo
- Department of Gastroenterology, Zunyi Medical College, Zunyi, China
| | - Gary Shull
- Department of of Molecular Genetics, University of Cincinnati, Cincinnati, OH, USA
| | - Ursula Seidler
- Department of Gastroenterology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
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Roulis M, Bongers G, Armaka M, Salviano T, He Z, Singh A, Seidler U, Becker C, Demengeot J, Furtado GC, Lira SA, Kollias G. Host and microbiota interactions are critical for development of murine Crohn's-like ileitis. Mucosal Immunol 2016; 9:787-97. [PMID: 26487367 PMCID: PMC5027991 DOI: 10.1038/mi.2015.102] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 08/31/2015] [Indexed: 02/04/2023]
Abstract
Deregulation of host-microbiota interactions in the gut is a pivotal characteristic of Crohn's disease. It remains unclear, however, whether commensals and/or the dysbiotic microbiota associated with pathology in humans are causally involved in Crohn's pathogenesis. Here, we show that Crohn's-like ileitis in Tnf(ΔARE/+) mice is microbiota-dependent. Germ-free Tnf(ΔARE/+) mice are disease-free and the microbiota and its innate recognition through Myd88 are indispensable for tumor necrosis factor (TNF) overexpression and disease initiation in this model. The epithelium of diseased mice shows no major defects in mucus barrier and paracellular permeability. However, Tnf(ΔARE/+) ileitis associates with the reduction of lysozyme-expressing Paneth cells, mediated by adaptive immune effectors. Furthermore, we show that established but not early ileitis in Tnf(ΔARE/+) mice involves defective expression of antimicrobials and dysbiosis, characterized by Firmicutes expansion, including epithelial-attaching segmented filamentous bacteria, and decreased abundance of Bacteroidetes. Microbiota modulation by antibiotic treatment at an early disease stage rescues ileitis. Our results suggest that the indigenous microbiota is sufficient to drive TNF overexpression and Crohn's ileitis in the genetically susceptible Tnf(ΔARE/+) hosts, whereas dysbiosis in this model results from disease-associated alterations including loss of lysozyme-expressing Paneth cells.
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Affiliation(s)
- M Roulis
- Institute of Immunology, Biomedical Sciences Research Center “Alexander Fleming”, Vari 16672, Greece
| | - G Bongers
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - M Armaka
- Institute of Immunology, Biomedical Sciences Research Center “Alexander Fleming”, Vari 16672, Greece
| | - T Salviano
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Z He
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - A Singh
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
| | - U Seidler
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
| | - C Becker
- Department of Medicine 1, Universitätsklinikum der Friedrich-Alexander-Universität, Erlangen, Germany
| | - J Demengeot
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - GC Furtado
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - SA Lira
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA,Address correspondence to: Sergio Lira, Immunology Institute, Icahn School of Medicine at Mount Sinai, 1425 Madison Ave, Box 1630, New York, NY 10029-6574. Phone: 1-212-659-9404; Fax: 1-212-849-2525; and George Kollias, Biomedical Sciences Research Center “Alexander Fleming”, 34, Al. Fleming Street, 16672 Vari, Greece. Phone: +302109656507; Fax: +302109656563; and Department of Physiology, Medical School, National & Kapodistrian University of Athens, 75 Micras Asias, Goudi-Athens, 115 27, Greece. Phone: +302107462507; Fax: +30210-7462571;
| | - G Kollias
- Institute of Immunology, Biomedical Sciences Research Center “Alexander Fleming”, Vari 16672, Greece,Second address: Department of Physiology, Medical School, National & Kapodistrian University of Athens, Athens 11527, Greece,Address correspondence to: Sergio Lira, Immunology Institute, Icahn School of Medicine at Mount Sinai, 1425 Madison Ave, Box 1630, New York, NY 10029-6574. Phone: 1-212-659-9404; Fax: 1-212-849-2525; and George Kollias, Biomedical Sciences Research Center “Alexander Fleming”, 34, Al. Fleming Street, 16672 Vari, Greece. Phone: +302109656507; Fax: +302109656563; and Department of Physiology, Medical School, National & Kapodistrian University of Athens, 75 Micras Asias, Goudi-Athens, 115 27, Greece. Phone: +302107462507; Fax: +30210-7462571;
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Magalhães D, Cabral JM, Soares-da-Silva P, Magro F. Role of epithelial ion transports in inflammatory bowel disease. Am J Physiol Gastrointest Liver Physiol 2016; 310:G460-76. [PMID: 26744474 DOI: 10.1152/ajpgi.00369.2015] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 01/02/2016] [Indexed: 02/06/2023]
Abstract
Inflammatory bowel disease (IBD) is a chronic inflammatory disorder with a complex pathogenesis. Diarrhea is a highly prevalent and often debilitating symptom of IBD patients that results, at least in part, from an intestinal hydroelectrolytic imbalance. Evidence suggests that reduced electrolyte absorption is more relevant than increased secretion to this disequilibrium. This systematic review analyses and integrates the current evidence on the roles of epithelial Na(+)-K(+)-ATPase (NKA), Na(+)/H(+) exchangers (NHEs), epithelial Na(+) channels (ENaC), and K(+) channels (KC) in IBD-associated diarrhea. NKA is the key driving force of the transepithelial ionic transport and its activity is decreased in IBD. In addition, the downregulation of apical NHE and ENaC and the upregulation of apical large-conductance KC all contribute to the IBD-associated diarrhea by lowering sodium absorption and/or increasing potassium secretion.
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Affiliation(s)
- Diogo Magalhães
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal; and MedInUP-Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal
| | - José Miguel Cabral
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal; and MedInUP-Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal
| | - Patrício Soares-da-Silva
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal; and MedInUP-Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal
| | - Fernando Magro
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal; and MedInUP-Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal
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47
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Spalinger MR, McCole DF, Rogler G, Scharl M. Protein tyrosine phosphatase non-receptor type 2 and inflammatory bowel disease. World J Gastroenterol 2016; 22:1034-1044. [PMID: 26811645 PMCID: PMC4716018 DOI: 10.3748/wjg.v22.i3.1034] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 08/31/2015] [Accepted: 11/19/2015] [Indexed: 02/06/2023] Open
Abstract
Genome wide association studies have associated single nucleotide polymorphisms within the gene locus encoding protein tyrosine phosphatase non-receptor type 2 (PTPN2) with the onset of inflammatory bowel disease (IBD) and other inflammatory disorders. Expression of PTPN2 is enhanced in actively inflamed intestinal tissue featuring a marked up-regulation in intestinal epithelial cells. PTPN2 deficient mice suffer from severe intestinal and systemic inflammation and display aberrant innate and adaptive immune responses. In particular, PTPN2 is involved in the regulation of inflammatory signalling cascades, and critical for protecting intestinal epithelial barrier function, regulating innate and adaptive immune responses, and finally for maintaining intestinal homeostasis. On one hand, dysfunction of PTPN2 has drastic effects on innate host defence mechanisms, including increased secretion of pro-inflammatory cytokines, limited autophagosome formation in response to invading pathogens, and disruption of the intestinal epithelial barrier. On the other hand, PTPN2 function is crucial for controlling adaptive immune functions, by regulating T cell proliferation and differentiation as well as maintaining T cell tolerance. In this way, dysfunction of PTPN2 contributes to the manifestation of IBD. The aim of this review is to present an overview of recent findings on the role of PTPN2 in intestinal homeostasis and the impact of dysfunctional PTPN2 on intestinal inflammation.
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48
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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.
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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
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49
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Wu KC, Lu YH, Peng YH, Hsu LC, Lin CJ. Effects of lipopolysaccharide on the expression of plasma membrane monoamine transporter (PMAT) at the blood-brain barrier and its implications to the transport of neurotoxins. J Neurochem 2015; 135:1178-88. [DOI: 10.1111/jnc.13363] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 08/26/2015] [Accepted: 08/28/2015] [Indexed: 02/06/2023]
Affiliation(s)
- Kuo-Chen Wu
- School of Pharmacy; College of Medicine; National Taiwan University; Taipei Taiwan
| | - Ya-Hsuan Lu
- School of Pharmacy; College of Medicine; National Taiwan University; Taipei Taiwan
| | - Yi-Hsuan Peng
- School of Pharmacy; College of Medicine; National Taiwan University; Taipei Taiwan
| | - Lih-Ching Hsu
- School of Pharmacy; College of Medicine; National Taiwan University; Taipei Taiwan
| | - Chun-Jung Lin
- School of Pharmacy; College of Medicine; National Taiwan University; Taipei Taiwan
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50
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Tang L, Peng M, Liu L, Chang W, Binder HJ, Cheng SX. Calcium-sensing receptor stimulates Cl(-)- and SCFA-dependent but inhibits cAMP-dependent HCO3(-) secretion in colon. Am J Physiol Gastrointest Liver Physiol 2015; 308:G874-83. [PMID: 25792563 PMCID: PMC4437021 DOI: 10.1152/ajpgi.00341.2014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 03/10/2015] [Indexed: 02/07/2023]
Abstract
Colonic bicarbonate (HCO3(-)) secretion is a well-established physiological process that is closely linked to overall fluid and electrolyte movement in the mammalian colon. These present studies show that extracellular calcium-sensing receptor (CaSR), a fundamental mechanism for sensing and regulating ionic and nutrient compositions of extracellular milieu in the small and large intestine, regulates HCO3(-) secretion. Basal and induced HCO3(-) secretory responses to CaSR agonists were determined by pH stat techniques used in conjunction with short-circuit current measurements in mucosa from rat distal colon mounted in Ussing chambers. R568, a specific CaSR activator, stimulated lumen Cl(-)- and short-chain fatty acid (SCFA)-dependent HCO3(-) secretion but inhibited cyclic nucleotide-activated HCO3(-) secretion. Consequently, at physiological conditions (either at basal or during lumen acid challenge) when electroneutral Cl(-)/HCO3(-) and SCFA/HCO3(-) exchangers dominate, CaSR stimulates HCO3(-) secretion; in contrast, in experimental conditions that stimulate fluid and HCO3(-) secretion, e.g., when forskolin activates electrogenic cystic fibrosis transmembrane conductance regulator-mediated HCO3(-) conductance, CaSR activation inhibits HCO3(-) secretion. Corresponding changes in JHCO3 (μeq·h(-1)·cm(-2), absence vs. presence of R568) were 0.18 ± 0.03 vs. 0.31 ± 0.08 under basal nonstimulated conditions and 1.85 ± 0.23 vs. 0.45 ± 0.06 under forskolin-stimulated conditions. Similarly, activation of CaSR by R568 stimulated Cl(-)- and SCFA-dependent HCO3(-) secretion and inhibited cAMP-dependent HCO3(-) secretion in colon mucosa of wild-type mice; such effects were abolished in CaSR-null mice. These results suggest a new paradigm for regulation of intestinal ion transport in which HCO3(-) secretion may be fine-tuned by CaSR in accordance with nutrient availability and state of digestion and absorption. The ability of CaSR agonists to inhibit secretagogue-induced intestinal HCO3(-) secretion suggests that modulation of CaSR activity may provide a new therapeutic approach to correct HCO3(-) deficit and metabolic acidosis, a primary cause of morbidity and mortality in acute infectious diarrheal illnesses.
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Affiliation(s)
- Lieqi Tang
- 1Division of Gastroenterology, Nutrition and Hepatology, Department of Pediatrics, University of Florida, Gainesville, Florida;
| | - Minzhi Peng
- 1Division of Gastroenterology, Nutrition and Hepatology, Department of Pediatrics, University of Florida, Gainesville, Florida;
| | - Li Liu
- 2Department of Pediatrics, Guangzhou Women and Children's Medical Center, Guangzhou, Guangdong, People's Republic of China;
| | - Wenhan Chang
- 3Endocrine Research, VA Medical Center, University of California at San Francisco, San Francisco, California;
| | - Henry J. Binder
- 4Department of Internal Medicine, Yale University, New Haven, Connecticut
| | - Sam X. Cheng
- 1Division of Gastroenterology, Nutrition and Hepatology, Department of Pediatrics, University of Florida, Gainesville, Florida;
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