1
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Omori S, Hanazono Y, Nishi H, Kinoshita K. The role of the STAS domain in SLC26A9 for chloride ion transporter function. Biophys J 2024; 123:1751-1762. [PMID: 38773769 PMCID: PMC11214054 DOI: 10.1016/j.bpj.2024.05.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 12/25/2023] [Accepted: 05/16/2024] [Indexed: 05/24/2024] Open
Abstract
The anion exchanger solute carrier family 26 (SLC26)A9, consisting of the transmembrane (TM) domain and the cytoplasmic STAS domain, plays an essential role in regulating chloride transport across cell membranes. Recent studies have indicated that C-terminal helices block the entrance of the putative ion transport pathway. However, the precise functions of the STAS domain and C-terminal helix, as well as the underlying molecular mechanisms governing the transport process, remain poorly understood. In this study, we performed molecular dynamics simulations of three distinct models of human SLC26A9, full-length, STAS domain removal (ΔSTAS), and C-terminus removal (ΔC), to investigate their conformational dynamics and ion-binding properties. Stable binding of ions to the binding sites was exclusively observed in the ΔC model in these simulations. Comparing the full-length and ΔC simulations, the ΔC model displayed enhanced motion of the STAS domain. Furthermore, comparing the ΔSTAS and ΔC simulations, the ΔSTAS simulation failed to exhibit stable ion bindings to the sites despite the absence of the C-terminus blocking the ion transmission pathway in both systems. These results suggest that the removal of the C-terminus not only unblocks the access of ions to the permeation pathway but also triggers STAS domain motion, gating the TM domain to promote ions' entry into their binding site. Further analysis revealed that the asymmetric motion of the STAS domain leads to the expansion of the ion permeation pathway within the TM domain, resulting in the stiffening of the flexible TM12 helix near the ion-binding site. This structural change in the TM12 helix stabilizes chloride ion binding, which is essential for SLC26A9's alternate-access mechanism. Overall, our study provides new insights into the molecular mechanisms of SLC26A9 transport and may pave the way for the development of novel treatments for diseases associated with dysregulated ion transport.
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Affiliation(s)
- Satoshi Omori
- Graduate School of Information Sciences, Tohoku University, Sendai, Miyagi, Japan; Department of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, Japan
| | - Yuya Hanazono
- Graduate School of Information Sciences, Tohoku University, Sendai, Miyagi, Japan; Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Hafumi Nishi
- Graduate School of Information Sciences, Tohoku University, Sendai, Miyagi, Japan; Faculty of Core Research, Ochanomizu University, Bunkyo-ku, Tokyo, Japan; Tohoku Medical Megabank Organization, Tohoku University, Sendai, Miyagi, Japan
| | - Kengo Kinoshita
- Graduate School of Information Sciences, Tohoku University, Sendai, Miyagi, Japan; Tohoku Medical Megabank Organization, Tohoku University, Sendai, Miyagi, Japan; Institute of Development, Aging, and Cancer, Tohoku University, Sendai, Miyagi, Japan.
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2
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Kato A, Pipil S, Ota C, Kusakabe M, Watanabe T, Nagashima A, Chen AP, Islam Z, Hayashi N, Wong MKS, Komada M, Romero MF, Takei Y. Convergent gene losses and pseudogenizations in multiple lineages of stomachless fishes. Commun Biol 2024; 7:408. [PMID: 38570609 PMCID: PMC10991444 DOI: 10.1038/s42003-024-06103-x] [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: 04/03/2023] [Accepted: 03/25/2024] [Indexed: 04/05/2024] Open
Abstract
The regressive evolution of independent lineages often results in convergent phenotypes. Several teleost groups display secondary loss of the stomach, and four gastric genes, atp4a, atp4b, pgc, and pga2 have been co-deleted in agastric (stomachless) fish. Analyses of genotypic convergence among agastric fishes showed that four genes, slc26a9, kcne2, cldn18a, and vsig1, were co-deleted or pseudogenized in most agastric fishes of the four major groups. kcne2 and vsig1 were also deleted or pseudogenized in the agastric monotreme echidna and platypus, respectively. In the stomachs of sticklebacks, these genes are expressed in gastric gland cells or surface epithelial cells. An ohnolog of cldn18 was retained in some agastric teleosts but exhibited an increased non-synonymous substitution when compared with gastric species. These results revealed novel convergent gene losses at multiple loci among the four major groups of agastric fish, as well as a single gene loss in the echidna and platypus.
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Affiliation(s)
- Akira Kato
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan.
- Department of Biological Sciences, Tokyo Institute of Technology, Yokohama, Japan.
- Center for Biological Resources and Informatics, Tokyo Institute of Technology, Yokohama, Japan.
- Department of Physiology & Biomedical Engineering, Mayo Clinic College of Medicine & Science, Rochester, MN, USA.
| | - Supriya Pipil
- Department of Marine Bioscience, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan
| | - Chihiro Ota
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Makoto Kusakabe
- Department of Marine Bioscience, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan
- Department of Biological Sciences, Faculty of Science, Shizuoka University, Shizuoka, Japan
| | - Taro Watanabe
- Department of Marine Bioscience, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan
| | - Ayumi Nagashima
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - An-Ping Chen
- Department of Physiology & Biomedical Engineering, Mayo Clinic College of Medicine & Science, Rochester, MN, USA
| | - Zinia Islam
- Department of Biological Sciences, Tokyo Institute of Technology, Yokohama, Japan
| | - Naoko Hayashi
- Department of Biological Sciences, Tokyo Institute of Technology, Yokohama, Japan
| | - Marty Kwok-Shing Wong
- Department of Marine Bioscience, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan
- Department of Biomolecular Science, Toho University, Funabashi, Japan
| | - Masayuki Komada
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Michael F Romero
- Department of Physiology & Biomedical Engineering, Mayo Clinic College of Medicine & Science, Rochester, MN, USA
- Department of Nephrology & Hypertension, Mayo Clinic College of Medicine & Science, Rochester, MN, USA
| | - Yoshio Takei
- Department of Marine Bioscience, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan
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3
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Pan C, Li H, Mustafa SB, Renqing C, Zhang Z, Li J, Song T, Wang G, Zhao W. Coping with extremes: the rumen transcriptome and microbiome co-regulate plateau adaptability of Xizang goat. BMC Genomics 2024; 25:258. [PMID: 38454325 PMCID: PMC10921577 DOI: 10.1186/s12864-024-10175-8] [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: 11/15/2023] [Accepted: 02/29/2024] [Indexed: 03/09/2024] Open
Abstract
The interactions between the rumen microbiota and the host are crucial for the digestive and absorptive processes of ruminants, and they are heavily influenced by the climatic conditions of their habitat. Owing to the harsh conditions of the high-altitude habitat, little is known about how ruminants regulate the host transcriptome and the composition of their rumen microbiota. Using the model species of goats, we examined the variations in the rumen microbiota, transcriptome regulation, and climate of the environment between high altitude (Lhasa, Xizang; 3650 m) and low altitude (Chengdu, Sichuan, China; 500 m) goats. The results of 16 S rRNA sequencing revealed variations in the abundance, diversity, and composition of rumen microbiota. Papillibacter, Quinella, and Saccharofermentans were chosen as potential microbes for the adaptation of Xizang goats to the harsh climate of the plateau by the Spearman correlation study of climate and microbiota. Based on rumen transcriptome sequencing analysis, 244 genes were found to be differentially expressed between Xizang goats and low-altitude goats, with 127 genes showing up-regulation and 117 genes showing down-regulation. SLC26A9, GPX3, ARRDC4, and COX1 were identified as potential candidates for plateau adaptation in Xizang goats. Moreover, the metabolism of fatty acids, arachidonic acids, pathway involving cytokines and their receptors could be essential for adaptation to plateau hypoxia and cold endurance. The expression of GPX3, a gene linked to plateau acclimatization in Xizang goats, was linked to the abundance of Anaerovibrio, and the expression of SLC26A9 was linked to the quantity of Selenomonas, according to ruminal microbiota and host Spearman correlation analysis. Our findings imply that in order to adapt harsh plateau conditions, Xizang goats have evolved to maximize digestion and absorption as well as to have a rumen microbiota suitable for the composition of their diet.
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Affiliation(s)
- Cheng Pan
- School of Life Science and Engineering, Southwest University of Science and Technology, 621000, Mianyang, Sichuan, China
| | - Haiyan Li
- School of Life Science and Engineering, Southwest University of Science and Technology, 621000, Mianyang, Sichuan, China
| | - Shehr Bano Mustafa
- School of Life Science and Engineering, Southwest University of Science and Technology, 621000, Mianyang, Sichuan, China
| | - Cuomu Renqing
- Institute of Animal Science, Xizang Academy of Agricultural and Animal Husbandry Science, 850009, Lhasa, Xizang, China
- Key Laboratory of Animal Genetics and Breeding on Xizang Plateau, Ministry of Agriculture and Rural Affairs, 850009, Lhasa, Xizang, China
| | - Zhenzhen Zhang
- School of Life Science and Engineering, Southwest University of Science and Technology, 621000, Mianyang, Sichuan, China
| | - Jingjing Li
- School of Life Science and Engineering, Southwest University of Science and Technology, 621000, Mianyang, Sichuan, China
| | - Tianzeng Song
- Institute of Animal Science, Xizang Academy of Agricultural and Animal Husbandry Science, 850009, Lhasa, Xizang, China
- Key Laboratory of Animal Genetics and Breeding on Xizang Plateau, Ministry of Agriculture and Rural Affairs, 850009, Lhasa, Xizang, China
| | - Gaofu Wang
- Chongqing Academy of Animal Sciences, 402460, Chongqing, Rongchang, China.
| | - Wangsheng Zhao
- School of Life Science and Engineering, Southwest University of Science and Technology, 621000, Mianyang, Sichuan, China.
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4
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Kunzelmann K, Centeio R, Ousingsawat J, Talbi K, Seidler U, Schreiber R. SLC26A9 in airways and intestine: secretion or absorption? Channels (Austin) 2023; 17:2186434. [PMID: 36866602 PMCID: PMC9988340 DOI: 10.1080/19336950.2023.2186434] [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: 03/04/2023] Open
Abstract
SLC26A9 is one out of 11 proteins that belong to the SLC26A family of anion transporters. Apart from expression in the gastrointestinal tract, SLC26A9 is also found in the respiratory system, in male tissues and in the skin. SLC26A9 has gained attention because of its modifier role in the gastrointestinal manifestation of cystic fibrosis (CF). SLC26A9 appears to have an impact on the extent of intestinal obstruction caused by meconium ileus. SLC26A9 supports duodenal bicarbonate secretion, but was assumed to provide a basal Cl- secretory pathway in airways. However, recent results show that basal airway Cl- secretion is due to cystic fibrosis conductance regulator (CFTR), while SLC26A9 may rather secrete HCO3-, thereby maintaining proper airway surface liquid (ASL) pH. Moreover, SLC26A9 does not secrete but probably supports reabsorption of fluid particularly in the alveolar space, which explains early death by neonatal distress in Slc26a9-knockout animals. While the novel SLC26A9 inhibitor S9-A13 helped to unmask the role of SLC26A9 in the airways, it also provided evidence for an additional role in acid secretion by gastric parietal cells. Here we discuss recent data on the function of SLC26A9 in airways and gut, and how S9-A13 may be useful in unraveling the physiological role of SLC26A9.
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Affiliation(s)
- Karl Kunzelmann
- Institut für Physiologie, Universität, Universitätsstraße 31, Regensburg, Germany
- CONTACT Karl Kunzelmann
| | - Raquel Centeio
- Institut für Physiologie, Universität, Universitätsstraße 31, Regensburg, Germany
| | - Jiraporn Ousingsawat
- Institut für Physiologie, Universität, Universitätsstraße 31, Regensburg, Germany
| | - Khaoula Talbi
- Institut für Physiologie, Universität, Universitätsstraße 31, Regensburg, Germany
| | - Ursula Seidler
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany
| | - Rainer Schreiber
- Institut für Physiologie, Universität, Universitätsstraße 31, Regensburg, Germany
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5
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Kunzelmann K, Ousingsawat J, Kraus A, Park JH, Marquardt T, Schreiber R, Buchholz B. Pathogenic Relationships in Cystic Fibrosis and Renal Diseases: CFTR, SLC26A9 and Anoctamins. Int J Mol Sci 2023; 24:13278. [PMID: 37686084 PMCID: PMC10487509 DOI: 10.3390/ijms241713278] [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: 06/28/2023] [Revised: 07/31/2023] [Accepted: 08/22/2023] [Indexed: 09/10/2023] Open
Abstract
The Cl--transporting proteins CFTR, SLC26A9, and anoctamin (ANO1; ANO6) appear to have more in common than initially suspected, as they all participate in the pathogenic process and clinical outcomes of airway and renal diseases. In the present review, we will therefore concentrate on recent findings concerning electrolyte transport in the airways and kidneys, and the role of CFTR, SLC26A9, and the anoctamins ANO1 and ANO6. Special emphasis will be placed on cystic fibrosis and asthma, as well as renal alkalosis and polycystic kidney disease. In essence, we will summarize recent evidence indicating that CFTR is the only relevant secretory Cl- channel in airways under basal (nonstimulated) conditions and after stimulation by secretagogues. Information is provided on the expressions of ANO1 and ANO6, which are important for the correct expression and function of CFTR. In addition, there is evidence that the Cl- transporter SLC26A9 expressed in the airways may have a reabsorptive rather than a Cl--secretory function. In the renal collecting ducts, bicarbonate secretion occurs through a synergistic action of CFTR and the Cl-/HCO3- transporter SLC26A4 (pendrin), which is probably supported by ANO1. Finally, in autosomal dominant polycystic kidney disease (ADPKD), the secretory function of CFTR in renal cyst formation may have been overestimated, whereas ANO1 and ANO6 have now been shown to be crucial in ADPKD and therefore represent new pharmacological targets for the treatment of polycystic kidney disease.
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Affiliation(s)
- Karl Kunzelmann
- Physiological Institute, University of Regensburg, University Street 31, 93053 Regensburg, Germany; (J.O.); (R.S.)
| | - Jiraporn Ousingsawat
- Physiological Institute, University of Regensburg, University Street 31, 93053 Regensburg, Germany; (J.O.); (R.S.)
| | - Andre Kraus
- Department of Nephrology and Hypertension, Friedrich Alexander University Erlangen Nuremberg, 91054 Erlangen, Germany; (A.K.); (B.B.)
| | - Julien H. Park
- Department of Pediatrics, University Hospital Münster, 48149 Münster, Germany; (J.H.P.); (T.M.)
| | - Thorsten Marquardt
- Department of Pediatrics, University Hospital Münster, 48149 Münster, Germany; (J.H.P.); (T.M.)
| | - Rainer Schreiber
- Physiological Institute, University of Regensburg, University Street 31, 93053 Regensburg, Germany; (J.O.); (R.S.)
| | - Björn Buchholz
- Department of Nephrology and Hypertension, Friedrich Alexander University Erlangen Nuremberg, 91054 Erlangen, Germany; (A.K.); (B.B.)
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6
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Jo S, Centeio R, Park J, Ousingsawat J, Jeon DK, Talbi K, Schreiber R, Ryu K, Kahlenberg K, Somoza V, Delpiano L, Gray MA, Amaral MD, Railean V, Beekman JM, Rodenburg LW, Namkung W, Kunzelmann K. The SLC26A9 inhibitor S9-A13 provides no evidence for a role of SLC26A9 in airway chloride secretion but suggests a contribution to regulation of ASL pH and gastric proton secretion. FASEB J 2022; 36:e22534. [PMID: 36183361 DOI: 10.1096/fj.202200313rr] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 08/11/2022] [Accepted: 08/24/2022] [Indexed: 11/11/2022]
Abstract
The solute carrier 26 family member A9 (SLC26A9) is an epithelial anion transporter that is assumed to contribute to airway chloride secretion and surface hydration. Whether SLC26A9 or CFTR is responsible for airway Cl- transport under basal conditions is still unclear, due to the lack of a specific inhibitor for SLC26A9. In the present study, we report a novel potent and specific inhibitor for SLC26A9, identified by screening of a drug-like molecule library and subsequent chemical modifications. The most potent compound S9-A13 inhibited SLC26A9 with an IC50 of 90.9 ± 13.4 nM. S9-A13 did not inhibit other members of the SLC26 family and had no effects on Cl- channels such as CFTR, TMEM16A, or VRAC. S9-A13 inhibited SLC26A9 Cl- currents in cells that lack expression of CFTR. It also inhibited proton secretion by HGT-1 human gastric cells. In contrast, S9-A13 had minimal effects on ion transport in human airway epithelia and mouse trachea, despite clear expression of SLC26A9 in the apical membrane of ciliated cells. In both tissues, basal and stimulated Cl- secretion was due to CFTR, while acidification of airway surface liquid by S9-A13 suggests a role of SLC26A9 for airway bicarbonate secretion.
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Affiliation(s)
- Sungwoo Jo
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, South Korea
| | - Raquel Centeio
- Physiological Institute, University of Regensburg, Regensburg, Germany
| | - Jinhong Park
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, South Korea
| | | | - Dong-Kyu Jeon
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, South Korea
| | - Khaoula Talbi
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
| | - Rainer Schreiber
- Physiological Institute, University of Regensburg, Regensburg, Germany
| | - Kunhi Ryu
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, South Korea
| | - Kristin Kahlenberg
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
| | - Veronika Somoza
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
| | - Livia Delpiano
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Michael A Gray
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Margarida D Amaral
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Lisbon, Portugal
| | - Violeta Railean
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Lisbon, Portugal
| | - Jeffrey M Beekman
- Regenerative Medicine Utrecht, University Medical Center, Utrecht University, Utrecht, Netherlands
| | - Lisa W Rodenburg
- Regenerative Medicine Utrecht, University Medical Center, Utrecht University, Utrecht, Netherlands
| | - Wan Namkung
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, South Korea
| | - Karl Kunzelmann
- Physiological Institute, University of Regensburg, Regensburg, Germany
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7
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Ammendolia DA, Bement WM, Brumell JH. Plasma membrane integrity: implications for health and disease. BMC Biol 2021; 19:71. [PMID: 33849525 PMCID: PMC8042475 DOI: 10.1186/s12915-021-00972-y] [Citation(s) in RCA: 93] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Accepted: 02/01/2021] [Indexed: 12/12/2022] Open
Abstract
Plasma membrane integrity is essential for cellular homeostasis. In vivo, cells experience plasma membrane damage from a multitude of stressors in the extra- and intra-cellular environment. To avoid lethal consequences, cells are equipped with repair pathways to restore membrane integrity. Here, we assess plasma membrane damage and repair from a whole-body perspective. We highlight the role of tissue-specific stressors in health and disease and examine membrane repair pathways across diverse cell types. Furthermore, we outline the impact of genetic and environmental factors on plasma membrane integrity and how these contribute to disease pathogenesis in different tissues.
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Affiliation(s)
- Dustin A Ammendolia
- Cell Biology Program, Hospital for Sick Children, 686 Bay Street PGCRL, Toronto, ON, M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A1, Canada
| | - William M Bement
- Center for Quantitative Cell Imaging and Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - John H Brumell
- Cell Biology Program, Hospital for Sick Children, 686 Bay Street PGCRL, Toronto, ON, M5G 0A4, Canada. .,Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A1, Canada. .,Institute of Medical Science, University of Toronto, Toronto, ON, M5S 1A1, Canada. .,SickKids IBD Centre, Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada.
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8
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Zajac M, Dreano E, Edwards A, Planelles G, Sermet-Gaudelus I. Airway Surface Liquid pH Regulation in Airway Epithelium Current Understandings and Gaps in Knowledge. Int J Mol Sci 2021; 22:3384. [PMID: 33806154 PMCID: PMC8037888 DOI: 10.3390/ijms22073384] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/08/2021] [Accepted: 03/08/2021] [Indexed: 12/22/2022] Open
Abstract
Knowledge on the mechanisms of acid and base secretion in airways has progressed recently. The aim of this review is to summarize the known mechanisms of airway surface liquid (ASL) pH regulation and their implication in lung diseases. Normal ASL is slightly acidic relative to the interstitium, and defects in ASL pH regulation are associated with various respiratory diseases, such as cystic fibrosis. Basolateral bicarbonate (HCO3-) entry occurs via the electrogenic, coupled transport of sodium (Na+) and HCO3-, and, together with carbonic anhydrase enzymatic activity, provides HCO3- for apical secretion. The latter mainly involves CFTR, the apical chloride/bicarbonate exchanger pendrin and paracellular transport. Proton (H+) secretion into ASL is crucial to maintain its relative acidity compared to the blood. This is enabled by H+ apical secretion, mainly involving H+/K+ ATPase and vacuolar H+-ATPase that carry H+ against the electrochemical potential gradient. Paracellular HCO3- transport, the direction of which depends on the ASL pH value, acts as an ASL protective buffering mechanism. How the transepithelial transport of H+ and HCO3- is coordinated to tightly regulate ASL pH remains poorly understood, and should be the focus of new studies.
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Affiliation(s)
- Miroslaw Zajac
- Department of Physics and Biophysics, Institute of Biology, Warsaw University of Life Sciences, 02-776 Warsaw, Poland;
| | - Elise Dreano
- Institut Necker Enfants Malades, INSERM U1151, 75015 Paris, France;
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, 75006 Paris, France;
| | - Aurelie Edwards
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA;
| | - Gabrielle Planelles
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, 75006 Paris, France;
- Laboratoire de Physiologie rénale et Tubulopathies, CNRS ERL 8228, 75006 Paris, France
| | - Isabelle Sermet-Gaudelus
- Institut Necker Enfants Malades, INSERM U1151, 75015 Paris, France;
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, 75006 Paris, France;
- Centre de Référence Maladies Rares, Mucoviscidose et Maladies de CFTR, Hôpital Necker Enfants Malades, 75015 Paris, France
- Clinical Trial Network, European Cystic Fibrosis Society, BT2 Belfast, Ireland
- European Respiratory Network Lung, 75006 Paris, France
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9
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Chi X, Jin X, Chen Y, Lu X, Tu X, Li X, Zhang Y, Lei J, Huang J, Huang Z, Zhou Q, Pan X. Structural insights into the gating mechanism of human SLC26A9 mediated by its C-terminal sequence. Cell Discov 2020; 6:55. [PMID: 32818062 PMCID: PMC7417587 DOI: 10.1038/s41421-020-00193-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 07/07/2020] [Indexed: 11/25/2022] Open
Abstract
The human SLC26 transporter family exhibits various transport characteristics, and family member SLC26A9 performs multiple roles, including acting as Cl-/HCO3- exchangers, Cl- channels, and Na+ transporters. Some mutations of SLC26A9 are correlated with abnormalities in respiration and digestion systems. As a potential target colocalizing with CFTR in cystic fibrosis patients, SLC26A9 is of great value in drug development. Here, we present a cryo-EM structure of the human SLC26A9 dimer at 2.6 Å resolution. A segment at the C-terminal end is bound to the entry of the intracellular vestibule of the putative transport pathway, which has been proven by electrophysiological experiments to be a gating modulator. Multiple chloride and sodium ions are resolved in the high-resolution structure, identifying novel ion-binding pockets for the first time. Together, our structure takes important steps in elucidating the structural features and regulatory mechanism of SLC26A9, with potential significance in the treatment of cystic fibrosis.
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Affiliation(s)
- Ximin Chi
- Key Laboratory of Structural Biology of Zhejiang Province, Institute of Biology, Westlake Institute for Advanced Study, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang 310024 China
| | - Xueqin Jin
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Yun Chen
- Key Laboratory of Structural Biology of Zhejiang Province, Institute of Biology, Westlake Institute for Advanced Study, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang 310024 China
| | - Xiaoli Lu
- Key Laboratory of Structural Biology of Zhejiang Province, Institute of Biology, Westlake Institute for Advanced Study, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang 310024 China
| | - Xinyu Tu
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing, 100191 China
| | - Xiaorong Li
- Key Laboratory of Structural Biology of Zhejiang Province, Institute of Biology, Westlake Institute for Advanced Study, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang 310024 China
| | - Yuanyuan Zhang
- Key Laboratory of Structural Biology of Zhejiang Province, Institute of Biology, Westlake Institute for Advanced Study, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang 310024 China
| | - Jianlin Lei
- Technology Center for Protein Sciences, Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Jing Huang
- Key Laboratory of Structural Biology of Zhejiang Province, Institute of Biology, Westlake Institute for Advanced Study, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang 310024 China
| | - Zhuo Huang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing, 100191 China
- Key Laboratory for Neuroscience, Ministry of Education/National Health and Family Planning Commission, Peking University, Beijing, 100191 China
| | - Qiang Zhou
- Key Laboratory of Structural Biology of Zhejiang Province, Institute of Biology, Westlake Institute for Advanced Study, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang 310024 China
| | - Xiaojing Pan
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084 China
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10
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Deficient Active Transport Activity in Healing Mucosa After Mild Gastric Epithelial Damage. Dig Dis Sci 2020; 65:119-131. [PMID: 31515722 PMCID: PMC7950857 DOI: 10.1007/s10620-019-05825-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 09/04/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Peptic ulcers recur, suggesting that ulcer healing may leave tissue predisposed to subsequent damage. In mice, we have identified that the regenerated epithelium found after ulcer healing will remain abnormal for months after healing. AIM To determine whether healed gastric mucosa has altered epithelial function, as measured by electrophysiologic parameters. METHOD Ulcers were induced in mouse gastric corpus by serosal local application of acetic acid. Thirty days or 8 months after ulcer induction, tissue was mounted in an Ussing chamber. Transepithelial electrophysiologic parameters (short-circuit current, Isc. resistance, R) were compared between the regenerated healed ulcer region and the non-ulcerated contralateral region, in response to luminal hyperosmolar NaCl challenge (0.5 M). RESULTS In unperturbed stomach, luminal application of hyperosmolar NaCl transiently dropped Isc followed by gradual recovery over 2 h. Compared to the starting baseline Isc, percent Isc recovery was reduced in 30-day healing mucosa, but not at 8 months. Prior to NaCl challenge, a lower baseline Isc was observed in trefoil factor 2 (TFF2) knockout (KO) versus wild type (WT), with no Isc recovery in either non-ulcerated or healing mucosa of KO. Inhibiting Na/H exchanger (NHE) transport in WT mucosa inhibited Isc recovery in response to luminal challenge. NHE2-KO baseline Isc was reduced versus NHE2-WT. In murine gastric organoids, NHE inhibition slowed recovery of intracellular pH and delayed the repair of photic induced damage. CONCLUSION Healing gastric mucosa has deficient electrophysiological recovery in response to hypertonic NaCl. TFF2 and NHE2 contribute to Isc regulation, and the recovery and healing of transepithelial function.
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11
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Quirós M, Nusrat A. Contribution of Wound-Associated Cells and Mediators in Orchestrating Gastrointestinal Mucosal Wound Repair. Annu Rev Physiol 2019; 81:189-209. [PMID: 30354933 PMCID: PMC7871200 DOI: 10.1146/annurev-physiol-020518-114504] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The gastrointestinal mucosa, structurally formed by the epithelium and lamina propria, serves as a selective barrier that separates luminal contents from the underlying tissues. Gastrointestinal mucosal wound repair is orchestrated by a series of spatial and temporal events that involve the epithelium, recruited immune cells, resident stromal cells, and the microbiota present in the wound bed. Upon injury, repair of the gastrointestinal barrier is mediated by collective migration, proliferation, and subsequent differentiation of epithelial cells. Epithelial repair is intimately regulated by a number of wound-associated cells that include immune cells and stromal cells in addition to mediators released by luminal microbiota. The highly regulated interaction of these cell types is perturbed in chronic inflammatory diseases that are associated with impaired wound healing. An improved understanding of prorepair mechanisms in the gastrointestinal mucosa will aid in the development of novel therapeutics that promote mucosal healing and reestablish the critical epithelial barrier function.
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Affiliation(s)
- Miguel Quirós
- Department of Pathology, University of Michigan, Ann Arbor, Michigan 48109, USA; ,
| | - Asma Nusrat
- Department of Pathology, University of Michigan, Ann Arbor, Michigan 48109, USA; ,
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12
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Balázs A, Mall MA. Role of the SLC26A9 Chloride Channel as Disease Modifier and Potential Therapeutic Target in Cystic Fibrosis. Front Pharmacol 2018; 9:1112. [PMID: 30327603 PMCID: PMC6174851 DOI: 10.3389/fphar.2018.01112] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 09/10/2018] [Indexed: 12/13/2022] Open
Abstract
The solute carrier family 26, member 9 (SLC26A9) is an epithelial chloride channel that is expressed in several organs affected in patients with cystic fibrosis (CF) including the lungs, the pancreas, and the intestine. Emerging evidence suggests SLC26A9 as a modulator of wild-type and mutant CFTR function, and as a potential alternative target to circumvent the basic ion transport defect caused by deficient CFTR-mediated chloride transport in CF. In this review, we summarize in vitro studies that revealed multifaceted molecular and functional interactions between SLC26A9 and CFTR that may be implicated in normal transepithelial chloride secretion in health, as well as impaired chloride/fluid transport in CF. Further, we focus on recent genetic association studies and investigations utilizing genetically modified mouse models that identified SLC26A9 as a disease modifier and supported an important role of this alternative chloride channel in the pathophysiology of several organ manifestations in CF, as well as other chronic lung diseases such as asthma and non-CF bronchiectasis. Collectively, these findings and the overlapping endogenous expression with CFTR suggest SLC26A9 an attractive novel therapeutic target that may be exploited to restore epithelial chloride secretion in patients with CF irrespective of their CFTR genotype. In addition, pharmacological activation of SLC26A9 may help to augment the effect of CFTR modulator therapies in patients with CF carrying responsive mutations such as the most common disease-causing mutation F508del-CFTR. However, future research and development including the identification of compounds that activate SLC26A9-mediated chloride transport are needed to explore this alternative chloride channel as a therapeutic target in CF and potentially other muco-obstructive lung diseases.
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Affiliation(s)
- Anita Balázs
- Department of Pediatric Pulmonology, Immunology and Intensive Care Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health, Berlin, Germany.,German Center for Lung Research, Giessen, Germany
| | - Marcus A Mall
- Department of Pediatric Pulmonology, Immunology and Intensive Care Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health, Berlin, Germany.,German Center for Lung Research, Giessen, Germany
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13
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Liu X, Li T, Tuo B. Physiological and Pathophysiological Relevance of the Anion Transporter Slc26a9 in Multiple Organs. Front Physiol 2018; 9:1197. [PMID: 30233393 PMCID: PMC6127633 DOI: 10.3389/fphys.2018.01197] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 08/08/2018] [Indexed: 02/05/2023] Open
Abstract
Transepithelial Cl- and HCO3- transport is crucial for the function of all epithelia, and HCO3- is a biological buffer that maintains acid-base homeostasis. In most epithelia, a series of Cl-/HCO3- exchangers and Cl- channels that mediate Cl- absorption and HCO3- secretion have been detected in the luminal and basolateral membranes. Slc26a9 belongs to the solute carrier 26 (Slc26) family of anion transporters expressed in the epithelia of multiple organs. This review summarizes the expression pattern and functional diversity of Slc26a9 in different systems based on all investigations performed thus far. Furthermore, the physical and functional interactions between Slc26a9 and cystic fibrosis transmembrane conductance regulator (CFTR) are discussed due to their overlapping expression pattern in multiple organs. Finally, we focus on the relationship between slc26a9 mutations and disease onset. An understanding of the physiological and pathophysiological relevance of Slc26a9 in multiple organs offers new possibilities for disease therapy.
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Affiliation(s)
- Xuemei Liu
- Department of Gastroenterology, Affiliated Hospital, Zunyi Medical University, Zunyi, China.,Digestive Disease Institute of Guizhou Province, Zunyi, China
| | - Taolang Li
- Department of Thyroid and Breast Surgery, Affiliated Hospital, Zunyi Medical University, Zunyi, China
| | - Biguang Tuo
- Department of Gastroenterology, Affiliated Hospital, Zunyi Medical University, Zunyi, China.,Digestive Disease Institute of Guizhou Province, Zunyi, China
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14
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Aihara E, Medina-Candelaria NM, Hanyu H, Matthis AL, Engevik KA, Gurniak CB, Witke W, Turner JR, Zhang T, Montrose MH. Cell injury triggers actin polymerization to initiate epithelial restitution. J Cell Sci 2018; 131:jcs.216317. [PMID: 30072444 DOI: 10.1242/jcs.216317] [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: 01/31/2018] [Accepted: 07/21/2018] [Indexed: 12/30/2022] Open
Abstract
The role of the actin cytoskeleton in the sequence of physiological epithelial repair in the intact epithelium has yet to be elucidated. Here, we explore the role of actin in gastric repair in vivo and in vitro gastric organoids (gastroids). In response to two-photon-induced cellular damage of either an in vivo gastric or in vitro gastroid epithelium, actin redistribution specifically occurred in the lateral membranes of cells neighboring the damaged cell. This was followed by their migration inward to close the gap at the basal pole of the dead cell, in parallel with exfoliation of the dead cell into the lumen. The repair and focal increase of actin was significantly blocked by treatment with EDTA or the inhibition of actin polymerization. Treatment with inhibitors of myosin light chain kinase, myosin II, trefoil factor 2 signaling or phospholipase C slowed both the initial actin redistribution and the repair. While Rac1 inhibition facilitated repair, inhibition of RhoA/Rho-associated protein kinase inhibited it. Inhibitors of focal adhesion kinase and Cdc42 had negligible effects. Hence, initial actin polymerization occurs in the lateral membrane, and is primarily important to initiate dead cell exfoliation and cell migration to close the gap.
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Affiliation(s)
- Eitaro Aihara
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, OH 45267, USA
| | | | - Hikaru Hanyu
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Andrea L Matthis
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Kristen A Engevik
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, OH 45267, USA
| | | | - Walter Witke
- Institute of Genetics, University of Bonn, Bonn, Germany
| | - Jerrold R Turner
- Departments of Pathology and Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Tongli Zhang
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Marshall H Montrose
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, OH 45267, USA
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15
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Paehler Vor der Nolte A, Chodisetti G, Yuan Z, Busch F, Riederer B, Luo M, Yu Y, Menon MB, Schneider A, Stripecke R, Nikolovska K, Yeruva S, Seidler U. Na + /H + exchanger NHE1 and NHE2 have opposite effects on migration velocity in rat gastric surface cells. J Cell Physiol 2017; 232:1669-1680. [PMID: 28019659 PMCID: PMC5396337 DOI: 10.1002/jcp.25758] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 12/21/2016] [Accepted: 12/22/2016] [Indexed: 12/13/2022]
Abstract
Following superficial injury, neighbouring gastric epithelial cells close the wound by rapid cell migration, a process called epithelial restitution. Na+/H+ exchange (NHE) inhibitors interfere with restitution, but the role of the different NHE isoforms expressed in gastric pit cells has remained elusive. The role of the basolaterally expressed NHE1 (Slc9a1) and the presumably apically expressed NHE2 (Slc9a2) in epithelial restitution was investigated in the nontransformed rat gastric surface cell line RGM1. Migration velocity was assessed by loading the cells with the fluorescent dye DiR and following closure of an experimental wound over time. Since RGM1 cells expressed very low NHE2 mRNA and have low transport activity, NHE2 was introduced by lentiviral gene transfer. In medium with pH 7.4, RGM1 cells displayed slow wound healing even in the absence of growth factors and independently of NHE activity. Growth factors accelerated wound healing in a partly NHE1‐dependent fashion. Preincubation with acidic pH 7.1 stimulated restitution in a NHE1‐dependent fashion. When pH 7.1 was maintained during the restitution period, migratory speed was reduced to ∼10% of the speed at pH 7,4, and the residual restitution was further inhibited by NHE1 inhibition. Lentiviral NHE2 expression increased the steady‐state pHi and reduced the restitution velocity after low pH preincubation, which was reversible by pharmacological NHE2 inhibition. The results demonstrate that in RGM1 cells, migratory velocity is increased by NHE1 activation, while NHE2 activity inhibit this process. A differential activation of NHE1 and NHE2 may therefore, play a role in the initiation and completion of the epithelial restitution process.
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Affiliation(s)
- Anja Paehler Vor der Nolte
- Departments of Gastroenterology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Giriprakash Chodisetti
- Departments of Gastroenterology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Zhenglin Yuan
- Departments of Gastroenterology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Florian Busch
- Departments of Gastroenterology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Brigitte Riederer
- Departments of Gastroenterology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Min Luo
- Departments of Gastroenterology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Yan Yu
- Departments of Gastroenterology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Manoj B Menon
- Departments of Biochemistry, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Andreas Schneider
- Departments of Hematology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Renata Stripecke
- Departments of Hematology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Katerina Nikolovska
- Departments of Gastroenterology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Sunil Yeruva
- Departments of Gastroenterology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
| | - Ursula Seidler
- Departments of Gastroenterology, Hemostatsis, Oncology and Stem Cell Transplantation, Medical School of Hannover, Germany
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16
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Oliveros-Bastidas A, Calcagno-Pissarelli MP, Naya M, Ávila-Núñez JL, Alonso-Amelot ME. Human gastric cancer, Helicobacter pylori and bracken carcinogens: A connecting hypothesis. Med Hypotheses 2016; 88:91-9. [DOI: 10.1016/j.mehy.2015.11.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Revised: 09/29/2015] [Accepted: 11/08/2015] [Indexed: 12/12/2022]
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17
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Novel Roles for Chloride Channels, Exchangers, and Regulators in Chronic Inflammatory Airway Diseases. Mediators Inflamm 2015; 2015:497387. [PMID: 26612971 PMCID: PMC4647060 DOI: 10.1155/2015/497387] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 10/13/2015] [Indexed: 01/14/2023] Open
Abstract
Chloride transport proteins play critical roles in inflammatory airway diseases, contributing to the detrimental aspects of mucus overproduction, mucus secretion, and airway constriction. However, they also play crucial roles in contributing to the innate immune properties of mucus and mucociliary clearance. In this review, we focus on the emerging novel roles for a chloride channel regulator (CLCA1), a calcium-activated chloride channel (TMEM16A), and two chloride exchangers (SLC26A4/pendrin and SLC26A9) in chronic inflammatory airway diseases.
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18
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Yi R, Wang R, Sun P, Zhao X. Antioxidant-mediated preventative effect of Dragon-pearl tea crude polyphenol extract on reserpine-induced gastric ulcers. Exp Ther Med 2015; 10:338-344. [PMID: 26170959 DOI: 10.3892/etm.2015.2473] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 04/08/2015] [Indexed: 02/07/2023] Open
Abstract
Dragon-pearl tea is a type of green tea commonly consumed in Southwest China. In the present study, the antioxidative and anti-gastric ulcer effects of Dragon-pearl tea crude polyphenols (DTCP) were determined in vitro and in vivo. Treatment with 25, 50 or 100 µg/ml DTCP resulted in notable antioxidant effects in vitro, which manifested as 2,2-diphenyl-1-picrylhydrazyl and OH radical-scavenging activity. Furthermore, using an in vivo mouse model, DTCP was shown to reduce the gastric ulcer area in the stomach, in which the 200 mg/kg DTCP dose exhibited the most marked effect, with a gastric ulcer index inhibitory rate of 72.63%. In addition, DTCP was demonstrated to improve stomach acidity conditions in vivo by increasing the pH and reducing the level of gastric juice, as compared with the reserpine-induced gastric ulcer control mice. Furthermore, DTCP altered the serum levels of a number of oxidation-related biomolecules, including superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), malondialdehyde (MDA), lipid peroxidation (LPO) and catalase (CAT), to subsequently exert an anti-gastric ulcer effect. Treatment with 50, 100 and 200 mg/kg DTCP increased the SOD, GSH-Px and CAT levels and reduced the MDA and LPO levels in the mouse model of gastric ulcers. These serum level alterations resulted in the modified serum levels of prostaglandin E2 (PGE2) and nitric oxide (NO), which are associated with gastric mucosal protection. A reverse transcription-quantitative polymerase chain reaction (RT-PCR) assay is a molecular biology experiment which could determine the changes of mRNA in tissues. Using the RT-PCR assay, DTCP was observed to increase the mRNA expression levels of certain genes associated with gastric ulcers: Epidermal growth factor, epidermal growth factor receptor, vascular endothelial growth factor and vascular endothelial growth factor receptor 1, while reducing gastrin expression levels. Therefore, the results indicated that DTCP induced a marked preventative effect on reserpine-induced gastric ulcers in vivo, as a result of its antioxidative capacity.
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Affiliation(s)
- Ruokun Yi
- Department of Food Science and Nutrition, Pusan National University, Busan 609-735, Republic of Korea
| | - Rui Wang
- Department of Biological and Chemical Engineering, Chongqing University of Education, Chongqing 400067, P.R. China
| | - Peng Sun
- Department of Biological and Chemical Engineering, Chongqing University of Education, Chongqing 400067, P.R. China
| | - Xin Zhao
- Department of Biological and Chemical Engineering, Chongqing University of Education, Chongqing 400067, P.R. China
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19
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Aihara E, Montrose MH. Importance of Ca(2+) in gastric epithelial restitution-new views revealed by real-time in vivo measurements. Curr Opin Pharmacol 2014; 19:76-83. [PMID: 25108560 DOI: 10.1016/j.coph.2014.07.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 07/22/2014] [Accepted: 07/22/2014] [Indexed: 12/14/2022]
Abstract
It has been a few decades since Ca(2+) was identified as one of the important factors that can accelerate gastric wound repair as well as contribute to epithelial homeostasis and regulation of gastric secretions. The mechanistic basis has remained largely unexplored in vivo because it was not possible to track in real time either intracellular Ca(2+) mobilization or wound repair in living tissues. Recent advances in technology, such as combining high resolution light microscopy and genetically encoded Ca(2+) reporters in mice, now allow the monitoring of Ca(2+) mobilization during gastric epithelial cell restitution. Ca(2+) is a ubiquitous second messenger that influences numerous cellular processes, including gastric acid/bicarbonate secretion, mucus secretion, and cell migration. We have demonstrated that cytosolic Ca(2+) mobilization within the restituting gastric epithelial cells is a central signal driving small wound repair. However, extracellular Ca(2+) is also mobilized in the juxtamucosal luminal space above a wound, and evidence suggests extracellular Ca(2+) is a third messenger that also promotes gastric epithelial restitution. Interplay between intracellular and extracellular Ca(2+) is necessary for efficient gastric epithelial restitution.
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Affiliation(s)
- Eitaro Aihara
- Department of Molecular and Cellular Physiology, University of Cincinnati, OH 45267, USA
| | - Marshall H Montrose
- Department of Molecular and Cellular Physiology, University of Cincinnati, OH 45267, USA.
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20
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Liu X, Li T, Riederer B, Lenzen H, Ludolph L, Yeruva S, Tuo B, Soleimani M, Seidler U. Loss of Slc26a9 anion transporter alters intestinal electrolyte and HCO3(-) transport and reduces survival in CFTR-deficient mice. Pflugers Arch 2014; 467:1261-75. [PMID: 24965066 PMCID: PMC4434866 DOI: 10.1007/s00424-014-1543-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 05/19/2014] [Accepted: 05/20/2014] [Indexed: 12/16/2022]
Abstract
Slc26a9 is an anion transporter that is strongly expressed in the stomach and lung. Slc26a9 variants were recently found associated with a higher incidence of meconium ileus in cystic fibrosis (CF) infants, raising the question whether Slc26a9 is expressed in the intestine and what its functional role is. Slc26a9 messenger RNA (mRNA) was found highly expressed in the mucosae of the murine and human upper gastrointestinal tract, with an abrupt decrease in expression levels beyond the duodenum. Absence of SLC26a9 expression strongly increased the intestinally related mortality in cystic fibrosis transmembrane conductance regulator (CFTR)-deficient mice. Proximal duodenal JHCO3(-) and fluid secretion were reduced in the absence of Slc26a9 expression. In the proximal duodenum of young Slc26a9 KO mice, the glands and villi/crypts were elongated and proliferation was enhanced. This difference was lost with ageing, as were the alterations in fluid movement, whereas the reduction in JHCO3(-) remained. Laser dissection followed by qPCR suggested Slc26a9 expression to be crypt-predominant in the duodenum. In summary, deletion of Slc26a9 caused bicarbonate secretory and fluid absorptive changes in the proximal duodenal mucosa and increased the postweaning death rates in CFTR-deficient mice. Functional alterations in the duodenum were most prominent at young ages. We assume that the association of meconium ileus and Slc26a9 variants may be related to maldigestion and impaired downstream signaling caused by loss of upper GI tract digestive functions, aggravating the situation of lack of secretion and sticky mucus at the site of obstruction in CF intestine.
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Affiliation(s)
- Xuemei Liu
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany
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21
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Functional interaction of the cystic fibrosis transmembrane conductance regulator with members of the SLC26 family of anion transporters (SLC26A8 and SLC26A9): physiological and pathophysiological relevance. Int J Biochem Cell Biol 2014; 52:58-67. [PMID: 24530837 DOI: 10.1016/j.biocel.2014.02.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 01/29/2014] [Accepted: 02/01/2014] [Indexed: 12/21/2022]
Abstract
The solute carrier 26 (SLC26) proteins are transmembrane proteins located at the plasma membrane of the cells and transporting a variety of monovalent and divalent anions, including chloride, bicarbonate, sulfate and oxalate. In humans, 11 members have been identified (SLC26A1 to SLC26A11) and although part of them display a very restricted tissue expression pattern, altogether they are widely expressed in the epithelial cells of the body where they contribute to the composition and the pH regulation of the secreted fluids. Importantly, mutations in SLC26A2, A3, A4, and A5 have been associated with distinct human genetic recessive disorders (i.e. diastrophic dysplasia, congenital chloride diarrhea, Pendred syndrome and deafness, respectively), demonstrating their essential and non-redundant functions in many tissues. During the last decade, physical and functional interactions of SLC26 members with the cystic fibrosis transmembrane conductance regulator (CFTR) have been highly documented, leading to the model of a crosstalk based on the binding of the SLC26 STAS domain to the CFTR regulatory domain. In this review, we will focus on the functional interaction of SLC26A8 and SLC26A9 with the CFTR channel. In particular we will highlight the newly published studies indicating that mutations in SLC26A8 and SLC26A9 proteins are associated with a deregulation of the CFTR anion transport activity in the pathophysiological context of the sperm and the pulmonary cells. These studies confirm the physiological relevance of SLC26 and CFTR cross-regulation, opening new gates for the treatment of cystic fibrosis.
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22
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Aihara E, Hentz CL, Korman AM, Perry NPJ, Prasad V, Shull GE, Montrose MH. In vivo epithelial wound repair requires mobilization of endogenous intracellular and extracellular calcium. J Biol Chem 2013; 288:33585-33597. [PMID: 24121509 DOI: 10.1074/jbc.m113.488098] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
We report that a localized intracellular and extracellular Ca(2+) mobilization occurs at the site of microscopic epithelial damage in vivo and is required to mediate tissue repair. Intravital confocal/two-photon microscopy continuously imaged the surgically exposed stomach mucosa of anesthetized mice while photodamage of gastric epithelial surface cells created a microscopic lesion that healed within 15 min. Transgenic mice with an intracellular Ca(2+)-sensitive protein (yellow cameleon 3.0) report that intracellular Ca(2+) selectively increases in restituting gastric epithelial cells adjacent to the damaged cells. Pretreatment with U-73122, indomethacin, 2-aminoethoxydiphenylborane, or verapamil inhibits repair of the damage and also inhibits the intracellular Ca(2+) increase. Confocal imaging of Fura-Red dye in luminal superfusate shows a localized extracellular Ca(2+) increase at the gastric surface adjacent to the damage that temporally follows intracellular Ca(2+) mobilization. Indomethacin and verapamil also inhibit the luminal Ca(2+) increase. Intracellular Ca(2+) chelation (1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid/acetoxymethyl ester, BAPTA/AM) fully inhibits intracellular and luminal Ca(2+) increases, whereas luminal calcium chelation (N-(2-hydroxyetheyl)-ethylendiamin-N,N,N'-triacetic acid trisodium, HEDTA) blocks the increase of luminal Ca(2+) and unevenly inhibits late-phase intracellular Ca(2+) mobilization. Both modes of Ca(2+) chelation slow gastric repair. In plasma membrane Ca-ATPase 1(+/-) mice, but not plasma membrane Ca-ATPase 4(-/-) mice, there is slowed epithelial repair and a diminished gastric surface Ca(2+) increase. We conclude that endogenous Ca(2+), mobilized by signaling pathways and transmembrane Ca(2+) transport, causes increased Ca(2+) levels at the epithelial damage site that are essential to gastric epithelial cell restitution in vivo.
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Affiliation(s)
- Eitaro Aihara
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio 45267
| | - Courtney L Hentz
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio 45267
| | - Abraham M Korman
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio 45267
| | - Nicholas P J Perry
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio 45267
| | - Vikram Prasad
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, Cincinnati, Ohio 45267
| | - Gary E Shull
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, Cincinnati, Ohio 45267
| | - Marshall H Montrose
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio 45267.
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Alper SL, Sharma AK. The SLC26 gene family of anion transporters and channels. Mol Aspects Med 2013; 34:494-515. [PMID: 23506885 DOI: 10.1016/j.mam.2012.07.009] [Citation(s) in RCA: 259] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 06/21/2012] [Indexed: 02/08/2023]
Abstract
The phylogenetically ancient SLC26 gene family encodes multifunctional anion exchangers and anion channels transporting a broad range of substrates, including Cl(-), HCO3(-), sulfate, oxalate, I(-), and formate. SLC26 polypeptides are characterized by N-terminal cytoplasmic domains, 10-14 hydrophobic transmembrane spans, and C-terminal cytoplasmic STAS domains, and appear to be homo-oligomeric. SLC26-related SulP proteins of marine bacteria likely transport HCO3(-) as part of oceanic carbon fixation. SulP genes present in antibiotic operons may provide sulfate for antibiotic biosynthetic pathways. SLC26-related Sultr proteins transport sulfate in unicellular eukaryotes and in plants. Mutations in three human SLC26 genes are associated with congenital or early onset Mendelian diseases: chondrodysplasias for SLC26A2, chloride diarrhea for SLC26A3, and deafness with enlargement of the vestibular aqueduct for SLC26A4. Additional disease phenotypes evident only in mouse knockout models include oxalate urolithiasis for Slc26a6 and Slc26a1, non-syndromic deafness for Slc26a5, gastric hypochlorhydria for Slc26a7 and Slc26a9, distal renal tubular acidosis for Slc26a7, and male infertility for Slc26a8. STAS domains are required for cell surface expression of SLC26 proteins, and contribute to regulation of the cystic fibrosis transmembrane regulator in complex, cell- and tissue-specific ways. The protein interactomes of SLC26 polypeptides are under active investigation.
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Affiliation(s)
- Seth L Alper
- Renal Division and Division of Molecular and Vascular Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
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24
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Bakouh N, Bienvenu T, Thomas A, Ehrenfeld J, Liote H, Roussel D, Duquesnoy P, Farman N, Viel M, Cherif-Zahar B, Amselem S, Taam RA, Edelman A, Planelles G, Sermet-Gaudelus I. Characterization of SLC26A9 in patients with CF-like lung disease. Hum Mutat 2013; 34:1404-14. [PMID: 24272871 DOI: 10.1002/humu.22382] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2012] [Accepted: 07/10/2013] [Indexed: 01/07/2023]
Abstract
Diffuse bronchiectasis is a common problem in respiratory clinics. We hypothesized that mutations in the solute carrier 26A9 (SLC26A9) gene, encoding for a chloride (Cl(-)) transporter mainly expressed in lungs, may lead to defects in mucociliary clearance. We describe two missense variants in the SLC26A9 gene in heterozygote patients presenting with diffuse idiopathic bronchiectasis : p.Arg575Trp, identified in a patient also heterozygote for p.Phe508del in the CFTR gene; and p.Val486Ile. Expression of both mutants in Xenopus laevis oocytes abolished SLC26A9-mediated Cl(-) conductance without decreasing protein membrane expression. Coexpression of CFTR with SLC26A9-p.Val486Ile resulted in a significant increase in the Cl(-) current induced by PKA stimulation, similar to that obtained in oocytes expressing CFTR and SLC26A9-WT. In contrast, coexpression of CFTR with SLC26A9-p.Arg575Trp inhibited SLC26A9-enhanced CFTR activation upon PKA. Further structure-function analyses led us to propose a site encompassing Arg575 in the SLC26A9-STAS domain for CFTR-SLC26A9 interaction. We hypothesize that SLC26A9-p.Arg575Trp prevented SLC26A9-mediated functional activation of CFTR by altering SLC26A9-CFTR interaction. Although we cannot confirm that these mutations by themselves are deleterious, we propose that they trigger the pathogenic role of a single CFTR mutation and provide insight into a novel mechanism of Cl(-) transport alteration across the respiratory mucosa, based on functional inhibition of CFTR.
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Affiliation(s)
- Naziha Bakouh
- INSERM U 845, Paris, France; Faculté de Médecine, Université René Descartes, Paris V, Paris, France
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Chen AP, Chang MH, Romero MF. Functional analysis of nonsynonymous single nucleotide polymorphisms in human SLC26A9. Hum Mutat 2012; 33:1275-84. [PMID: 22544634 PMCID: PMC3399991 DOI: 10.1002/humu.22107] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 04/16/2012] [Indexed: 01/13/2023]
Abstract
Slc26 anion transporters play crucial roles in transepithelial Cl(-) absorption and HCO(3)(-) secretion; Slc26 protein mutations lead to several diseases. Slc26a9 functions as a Cl(-) channel and electrogenic Cl(-)--HCO(3)(-) exchanger, and can interact with cystic fibrosis transmembrane conductance regulator. Slc26a9(-/-) mice have reduced gastric acid secretion, yet no human disease is currently associated with SLC26A9 coding mutations. Therefore, we tested the function of nonsynonymous, coding, single nucleotide polymorphisms (cSNPs) of SLC26A9. Presently, eight cSNPs are NCBI documented: Y70N, T127N, I384T, R575W, P606L, V622L, V744M, and H748R. Using two-electrode voltage-clamp and anion selective electrodes, we measured the biophysical consequences of these cSNPs. Y70N (cytoplasmic N-terminus) displays higher channel activity and enhanced Cl(-)--HCO(3)(-) exchange. T127N (transmembrane) results in smaller halide currents but not for SCN(-). V622L (STAS domain) and V744M (STAS adjacent) decreased plasma membrane expression, which partially accounts for decreased whole cell currents. Nevertheless, V622L transport is reduced to ∼50%. SLC26A9 polymorphisms lead to several function modifications (increased activity, decreased activity, altered protein expression), which could lead to a spectrum of pathophysiologies. Thus, knowing an individual's SLC26A9 genetics becomes important for understanding disease potentially caused by SLC26A9 mutations or modifying diseases, for example, cystic fibrosis. Our results also provide a framework to understand SLC26A9 transport modalities and structure-function relationships.
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Affiliation(s)
- An-Ping Chen
- Physiology & Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
| | - Min-Hwang Chang
- Physiology & Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
| | - Michael F. Romero
- Physiology & Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
- Nephrology & Hypertension, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
- O’Brien Urology Research Center, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
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Demitrack ES, Aihara E, Kenny S, Varro A, Montrose MH. Inhibitors of acid secretion can benefit gastric wound repair independent of luminal pH effects on the site of damage. Gut 2012; 61:804-11. [PMID: 21997560 PMCID: PMC3418063 DOI: 10.1136/gutjnl-2011-300420] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
BACKGROUND AND AIMS The authors' goal was to measure pH at the gastric surface (pH₀) to understand how acid secretion affects the repair of microscopic injury to the gastric epithelium. METHODS Microscopic gastric damage was induced by laser light, during confocal/two-photon imaging of pH-sensitive dyes (Cl-NERF, BCECF) that were superfused over the mucosal surface of the exposed gastric corpus of anaesthetised mice. The progression of repair was measured in parallel with pH₀. Experimental conditions included varying pH of luminal superfusates, and using omeprazole (60 mg/kg ip) or famotidine (30 mg/kg ip) to inhibit acid secretion. RESULTS Similar rates of epithelial repair and resting pH₀ values (∼pH 4) were reported in the presence of luminal pH 3 or pH 5. Epithelial repair was unreliable at luminal pH 2 and pH₀ was lower (2.5±0.2, P <0.05 vs pH 3). Epithelial repair was slower at luminal pH 7 and pH₀ was higher (6.4±0.1, P<0.001). In all conditions, pH₀ increased adjacent to damage. At luminal pH 3 or pH 7, omeprazole reduced maximal damage size and accelerated epithelial repair, although only at pH 3 did omeprazole further increase surface pH above the level caused by imposed damage. At luminal pH 7, famotidine also reduced maximal damage size and accelerated epithelial repair. Neither famotidine nor omeprazole raised plasma gastrin levels during the time course of the experiments. CONCLUSIONS Epithelial repair in vivo is affected by luminal pH variation, but the beneficial effects of acutely blocking acid secretion extend beyond simply raising luminal and/or surface pH.
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Affiliation(s)
- Elise S Demitrack
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Eitaro Aihara
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Susan Kenny
- Department of Physiology, University of Liverpool, Liverpool, UK
| | - Andrea Varro
- Department of Physiology, University of Liverpool, Liverpool, UK
| | - Marshall H Montrose
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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McColl KEL, Aihara E, Kenny S, Varro A, Montrose MH. The elegance of the gastric mucosal barrier: designed by nature for nature. Gut 2012; 61:787-8. [PMID: 22147513 DOI: 10.1136/gutjnl-2011-301612] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Kenneth E L McColl
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, 44 Church Street, Glasgow G11 6NT, UK.
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Abstract
PURPOSE OF REVIEW We have highlighted the recent findings relating to gastroduodenal mucosal defense, including elements that may contribute to the failure of defense systems and factors that enhance mucosal healing, focusing on findings that elucidate new pathophysiological mechanisms. RECENT FINDINGS Bicarbonate secretion is mediated by multiple types of prostaglandin E synthases, including membrane-bound prostaglandin E synthase-1. Mucins, growth factors, and trefoil factors are involved in accelerating gastric injury healing through epithelial reconstruction. A combination of NSAIDs and bile induce greater damage on the mucosa than if the two agents were acting alone. Proton pump inhibitors defend the mucosa from injury by promoting cellular restitution as well as inhibiting gastric acid secretion and reactive oxygen species (ROS) damage. Roxatidine, a novel H2 receptor antagonist, acts through a mechanism that involves nitric oxide. Melatonin enhances angiogenesis through the upregulation of plasma levels of gastrin and matrix metalloproteinase expression. The mucosal protective drug polaprezinc exhibits ROS-quenching activities. Lipopolysaccharides induce oxidative stress mediated by p38 mitogen-activated protein kinase (p38 MAPK). Aging weakens gastroduodenal mucosal defense mechanisms. SUMMARY There is a wide array of pathways leading to gastroduodenal mucosal injury in addition to protective defense mechanisms that counteract them to maintain homeostasis. Increased understanding of these systems may help identify novel molecular targets for the prevention and treatment of mucosal injury.
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Xue L, Aihara E, Wang TC, Montrose MH. Trefoil factor 2 requires Na/H exchanger 2 activity to enhance mouse gastric epithelial repair. J Biol Chem 2011; 286:38375-38382. [PMID: 21900251 DOI: 10.1074/jbc.m111.268219] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Trefoil factor (TFF) peptides are pivotal for gastric restitution after surface epithelial damage, but TFF cellular targets that promote cell migration are poorly understood. Conversely, Na/H exchangers (NHE) are often implicated in cellular migration but have a controversial role in gastric restitution. Using intravital microscopy to create microscopic lesions in the mouse gastric surface epithelium and directly measure epithelial restitution, we evaluated whether TFFs and NHE isoforms share a common pathway to promote epithelial repair. Blocking Na/H exchange (luminal 10 μm 5-(N-ethyl-N-isopropyl) amiloride or 25 μm HOE694) slows restitution 72-83% in wild-type or NHE1(-/-) mice. In contrast, HOE694 has no effect on the intrinsically defective gastric restitution in NHE2(-/-) mice or TFF2(-/-) mice. In TFF2(-/-) mice, NHE2 protein is reduced 23%, NHE2 remains localized to apical membranes of surface epithelium, and NHE1 protein amount or localization is unchanged. The action of topical rat TFF3 to accelerate restitution in TFF2(-/-) mice was inhibited by AMD3100 (CXCR4 receptor antagonist). Furthermore, rat TFF3 did not rescue restitution when NHE2 was inhibited [TFF2(-/-) mice +HOE694, or NHE2(-/-) mice]. HOE694 had no effect on pH at the juxtamucosal surface before or after damage. We conclude that functional NHE2, but not NHE1, is essential for mouse gastric epithelial restitution and that TFFs activate epithelial repair via NHE2.
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Affiliation(s)
- Lin Xue
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio 45267
| | - Eitaro Aihara
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio 45267
| | - Timothy C Wang
- Division of Digestive and Liver Diseases, Columbia University Medical Center, New York, New York 10032
| | - Marshall H Montrose
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio 45267.
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