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Petersen OH. Physiology and Pathophysiology 2023. FUNCTION (OXFORD, ENGLAND) 2023; 4:zqad005. [PMID: 36788946 PMCID: PMC9912100 DOI: 10.1093/function/zqad005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Accepted: 01/29/2023] [Indexed: 02/04/2023]
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Mistlberger-Reiner A, Sterneder S, Reipert S, Wolske S, Somoza V. Extracellular Vesicles and Particles Modulate Proton Secretion in a Model of Human Parietal Cells. ACS OMEGA 2023; 8:2213-2226. [PMID: 36687051 PMCID: PMC9850724 DOI: 10.1021/acsomega.2c06442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 12/19/2022] [Indexed: 06/17/2023]
Abstract
The secretion of extracellular vesicles and particles (EVPs) is an important mechanism of cellular communication. In this work, we demonstrate a functional role of EVPs in mechanisms regulating gastric acid secretion. HGT-1 cells were used as a model system to assess proton secretion. First, in order to prove EVP secretion by HGT-1 cells, EVPs were isolated by size exclusion chromatography and characterized by nanoparticle tracking analysis, Western blot, and cryo transmission electron microscopy. For examination of the potential role of EVPs in proton secretion, HGT-1 cells were treated with pharmacological EV-inhibitors, resulting in a reduction of histamine-induced proton secretion. To demonstrate the functional role of EVPs in the mechanism of proton secretion, EVP-conditioned supernatant was collected after stimulation of HGT-1 cells with histamine, fractionated, and subjected to an activity screening. The results revealed constituents of the HGT-1-derived secretome with an MW of >100 kDa (including EVPs) to modulate proton secretion, while smaller constituents had no effect. Finally, a dose-dependent modulatory effect on proton secretion of HGT-1 cells was demonstrated by isolated HGT-1-derived EVPs. Hence, this study presents first results on the potential function of EVPs as a previously undiscovered mechanism of regulation of gastric acid secretion by parietal cells.
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Affiliation(s)
- Agnes Mistlberger-Reiner
- Department
of Physiological Chemistry, Faculty of Chemistry, University of Vienna, Vienna 1090, Austria
| | - Sonja Sterneder
- Department
of Physiological Chemistry, Faculty of Chemistry, University of Vienna, Vienna 1090, Austria
| | - Siegfried Reipert
- Core
Facility Cell Imaging and Ultrastructure Research, University of Vienna, Vienna 1030, Austria
| | - Sara Wolske
- Department
of Physiological Chemistry, Faculty of Chemistry, University of Vienna, Vienna 1090, Austria
| | - Veronika Somoza
- Department
of Physiological Chemistry, Faculty of Chemistry, University of Vienna, Vienna 1090, Austria
- Leibniz-Institute
for Food Systems Biology at the Technical University of Munich, Freising 85354, Germany
- Nutritional
Systems Biology, Technical University of
Munich, Freising 85354, Germany
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3
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Nakamura M, Murasato F, Øverby A, Kodama Y, Michimae H, Sasaki K, Flahou B, Haesebrouck F, Murayama SY, Takahashi S, Uchida M, Suzuki H, Matsui H. Effect of Acid Suppressants on Non–Helicobacter pylori Helicobacters Within Parietal Cells. Front Pharmacol 2022; 13:692437. [PMID: 35935877 PMCID: PMC9355715 DOI: 10.3389/fphar.2022.692437] [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: 04/08/2021] [Accepted: 06/14/2022] [Indexed: 12/22/2022] Open
Abstract
We investigated the effect of increased pH induced by acid suppressants on the viability of non–Helicobacter pylori helicobacters (NHPHs) within parietal cell intracellular canaliculi and fundic glandular lumina by immunohistochemistry, electron microscopy, quantitative PCR, urea breath tests, and using a bilayer culture system. Three months before the experiment, mice were infected with the NHPH H. suis and then treated with famotidine (2 mg/kg body weight [BW], once daily), lansoprazole (30 mg/kg BW, once daily), or vonoprazan (20 mg/kg BW, once daily) for 3 days. Immunohistochemical studies using the TUNEL method, quantitative PCR analysis, and urea breath tests were performed. PCR analysis showed a decrease in the NHPH quantity after vonoprazan treatment. Urea breath tests revealed a significant decrease in the NHPH urease activity after vonoprazan, lansoprazole, and famotidine treatments for 3 days; however, 4 days after the treatment, urease activity reversed to the pretreatment level for each treatment group. Electron microscopy revealed an increase in the damaged NHPH after vonoprazan treatment. The TUNEL method revealed apoptotic NHPH within parietal cells after vonoprazan treatment. The bilayer culture results demonstrated that NHPH moved more quickly at a pH of 4.0 than at a pH of 3.0, 5.0, and 6.5, and electron microscopy revealed a change from the spiral form to the coccoid form under near-neutral pH conditions. We thus proposed that acid suppressants, especially vonoprazan, induce NHPH damage by altering pH.
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Affiliation(s)
- Masahiko Nakamura
- Ohmura Satoshi Memorial Institute, Kitasato University, Tokyo, Japan
- *Correspondence: Masahiko Nakamura,
| | - Futa Murasato
- School of Pharmacy, Kitasato University, Tokyo, Japan
| | - Anders Øverby
- Center of Education in Kongsvinger, Kongsvinger, Norway
| | - Yosuke Kodama
- School of Pharmacy, Kitasato University, Tokyo, Japan
| | - Hirofumi Michimae
- Department of Clinical Medicine (Biostatistics), School of Pharmacy, Kitasato University, Tokyo, Japan
| | - Kazuki Sasaki
- School of Pharmacy, Kitasato University, Tokyo, Japan
| | - Bram Flahou
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Freddy Haesebrouck
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Somay Y. Murayama
- Department of Fungal Infection, National Institute of Infectious Diseases, Tokyo, Japan
| | | | - Masayuki Uchida
- Division of Research and Development, Meiji Dairies Corporation, Food Science Institute, Odawara, Japan
| | - Hidekazu Suzuki
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Tokai University School of Medicine, Isehara, Japan
| | - Hidenori Matsui
- Ohmura Satoshi Memorial Institute, Kitasato University, Tokyo, Japan
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4
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Tchernookova BK, Gongwer MW, George A, Goeglein B, Powell AM, Caringal HL, Leuschner T, Phillips AG, Schantz AW, Kiedrowski L, Chappell R, Kreitzer MA, Malchow RP. ATP-mediated increase in H + flux from retinal Müller cells: a role for Na +/H + exchange. J Neurophysiol 2020; 125:184-198. [PMID: 33206577 DOI: 10.1152/jn.00546.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Small alterations in extracellular H+ can profoundly alter neurotransmitter release by neurons. We examined mechanisms by which extracellular ATP induces an extracellular H+ flux from Müller glial cells, which surround synaptic connections throughout the vertebrate retina. Müller glia were isolated from tiger salamander retinae and H+ fluxes examined using self-referencing H+-selective microelectrodes. Experiments were performed in 1 mM HEPES with no bicarbonate present. Replacement of extracellular sodium by choline decreased H+ efflux induced by 10 µM ATP by 75%. ATP-induced H+ efflux was also reduced by Na+/H+ exchange inhibitors. Amiloride reduced H+ efflux initiated by 10 µM ATP by 60%, while 10 µM cariporide decreased H+ flux by 37%, and 25 µM zoniporide reduced H+ flux by 32%. ATP-induced H+ fluxes were not significantly altered by the K+/H+ pump blockers SCH28080 or TAK438, and replacement of all extracellular chloride with gluconate was without effect on H+ fluxes. Recordings of ATP-induced H+ efflux from cells that were simultaneously whole cell voltage clamped revealed no effect of membrane potential from -70 mV to 0 mV. Restoration of extracellular potassium after cells were bathed in 0 mM potassium produced a transient alteration in ATP-dependent H+ efflux. The transient response to extracellular potassium occurred only when extracellular sodium was present and was abolished by 1 mM ouabain, suggesting that alterations in sodium gradients were mediated by Na+/K+-ATPase activity. Our data indicate that the majority of H+ efflux elicited by extracellular ATP from isolated Müller cells is mediated by Na+/H+ exchange.NEW & NOTEWORTHY Glial cells are known to regulate neuronal activity, but the exact mechanism(s) whereby these "support" cells modulate synaptic transmission remains unclear. Small changes in extracellular levels of acidity are known to be particularly powerful regulators of neurotransmitter release. Here, we show that extracellular ATP, known to be a potent activator of glial cells, induces H+ efflux from retinal Müller (glial) cells and that the bulk of the H+ efflux is mediated by Na+/H+ exchange.
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Affiliation(s)
| | | | - Alexis George
- Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Brock Goeglein
- Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Alyssa M Powell
- Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | | | - Thomas Leuschner
- Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Anna G Phillips
- Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Adam W Schantz
- Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Lech Kiedrowski
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois.,Spot Cells LLC, Chicago, Illinois
| | - Richard Chappell
- Department of Physiology and Biophysics, University at Buffalo, Buffalo, New York.,Eugene Bell Center, Marine Biological Laboratory, Woods Hole, Massachusetts
| | | | - Robert Paul Malchow
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois.,Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois
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5
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Physiological Significance of Ion Transporters and Channels in the Stomach and Pathophysiological Relevance in Gastric Cancer. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2020; 2020:2869138. [PMID: 32104192 PMCID: PMC7040404 DOI: 10.1155/2020/2869138] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 12/17/2019] [Accepted: 01/08/2020] [Indexed: 12/26/2022]
Abstract
Gastric cancer (GC) is a highly invasive and fatal malignant disease that accounts for 5.7% of new global cancer cases and is the third leading cause of cancer-related death. Acid/base homeostasis is critical for organisms because protein and enzyme function, cellular structure, and plasma membrane permeability change with pH. Various ion transporters are expressed in normal gastric mucosal epithelial cells and regulate gastric acid secretion, ion transport, and fluid absorption, thereby stabilizing the differentiation and homeostasis of gastric mucosal epithelial cells. Ion transporter dysfunction results in disordered ion transport, mucosa barrier dysfunction, and acid/base disturbances, causing gastric acid-related diseases such as chronic atrophic gastritis (CAG) and GC. This review summarizes the physiological functions of multiple ion transporters and channels in the stomach, including Cl− channels, Cl−/HCO3− exchangers, sodium/hydrogen exchangers (NHEs), and potassium (K+) channels, and their pathophysiological relevance in GC.
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Molecular mechanisms of Wischnewski spot development on gastric mucosa in fatal hypothermia: an experimental study in rats. Sci Rep 2020; 10:1877. [PMID: 32024924 PMCID: PMC7002760 DOI: 10.1038/s41598-020-58894-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 01/17/2020] [Indexed: 02/02/2023] Open
Abstract
Numerous dark-brown-coloured small spots called “Wischnewski spots” are often observed in the gastric mucosa in the patients dying of hypothermia, but the molecular mechanisms through which they develop remain unclear. We hypothesised that hypothermia may activate the secretion of gastric acid and pepsin, leading to the development of the spots. To investigate this, we performed experiments using organotypic rat gastric tissue slices cultured at 37 °C (control) or 32 °C (cold). Cold loading for 6 h lowered the extracellular pH in the culture medium. The mRNA expression of gastrin, which regulates gastric acid secretion, increased after cold loading for 3 h. Cold loading increased the expression of gastric H+,K+-ATPase pump protein in the apical canalicular membrane and resulted in dynamic morphological changes in parietal cells. Cold loading resulted in an increased abundance of pepsin C protein and an elevated mRNA expression of its precursor progastricsin. Collectively, our findings clarified that cold stress induces acidification by activating gastric H+,K+-ATPase pumps and promoting pepsin C release through inducing progastricsin expression on the gastric mucosa, leading to tiny haemorrhages or erosions of the gastric mucosa that manifest as Wischnewski spots in fatal hypothermia.
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7
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Zhang Y, Takahashi Y, Hong SP, Liu F, Bednarska J, Goff PS, Novak P, Shevchuk A, Gopal S, Barozzi I, Magnani L, Sakai H, Suguru Y, Fujii T, Erofeev A, Gorelkin P, Majouga A, Weiss DJ, Edwards C, Ivanov AP, Klenerman D, Sviderskaya EV, Edel JB, Korchev Y. High-resolution label-free 3D mapping of extracellular pH of single living cells. Nat Commun 2019; 10:5610. [PMID: 31811139 PMCID: PMC6898398 DOI: 10.1038/s41467-019-13535-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 11/13/2019] [Indexed: 01/05/2023] Open
Abstract
Dynamic mapping of extracellular pH (pHe) at the single-cell level is critical for understanding the role of H+ in cellular and subcellular processes, with particular importance in cancer. While several pHe sensing techniques have been developed, accessing this information at the single-cell level requires improvement in sensitivity, spatial and temporal resolution. We report on a zwitterionic label-free pH nanoprobe that addresses these long-standing challenges. The probe has a sensitivity > 0.01 units, 2 ms response time, and 50 nm spatial resolution. The platform was integrated into a double-barrel nanoprobe combining pH sensing with feedback-controlled distance dependance via Scanning Ion Conductance Microscopy. This allows for the simultaneous 3D topographical imaging and pHe monitoring of living cancer cells. These classes of nanoprobes were used for real-time high spatiotemporal resolution pHe mapping at the subcellular level and revealed tumour heterogeneity of the peri-cellular environments of melanoma and breast cancer cells.
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Affiliation(s)
- Yanjun Zhang
- Department of Medicine, Imperial College London, London, W12 0NN, UK.
- Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, 300052, China.
| | - Yasufumi Takahashi
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Saitama, 332-0012, Japan
| | - Sung Pil Hong
- Department of Surgery and Cancer, Imperial College London, London, W12 0NN, UK
| | - Fengjie Liu
- Department of Earth Science & Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Joanna Bednarska
- Department of Medicine, Imperial College London, London, W12 0NN, UK
| | - Philip S Goff
- Cell Biology Research Centre, Molecular and Clinical Sciences Research Institute, St George's, University of London, London, SW17 0RE, UK
| | - Pavel Novak
- Department of Medicine, Imperial College London, London, W12 0NN, UK
- National University of Science and Technology "MISIS", Leninskiy prospect 4, 119991, Moscow, Russian Federation
| | - Andrew Shevchuk
- Department of Medicine, Imperial College London, London, W12 0NN, UK
| | - Sahana Gopal
- Department of Medicine, Imperial College London, London, W12 0NN, UK
| | - Iros Barozzi
- Department of Surgery and Cancer, Imperial College London, London, W12 0NN, UK
| | - Luca Magnani
- Department of Surgery and Cancer, Imperial College London, London, W12 0NN, UK
| | - Hideki Sakai
- Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, 930-0194, Japan
| | - Yoshimoto Suguru
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan
| | - Takuto Fujii
- Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, 930-0194, Japan
| | - Alexander Erofeev
- National University of Science and Technology "MISIS", Leninskiy prospect 4, 119991, Moscow, Russian Federation
- Department of Chemistry, Lomonosov Moscow State University, Leninskiye gory 1-3, GSP-1, 119991, Moscow, Russian Federation
| | - Peter Gorelkin
- National University of Science and Technology "MISIS", Leninskiy prospect 4, 119991, Moscow, Russian Federation
| | - Alexander Majouga
- Department of Chemistry, Lomonosov Moscow State University, Leninskiye gory 1-3, GSP-1, 119991, Moscow, Russian Federation
| | - Dominik J Weiss
- Department of Earth Science & Engineering, Imperial College London, London, SW7 2AZ, UK
| | | | - Aleksandar P Ivanov
- Department of Chemistry, Imperial College London, Molecular Science Research Hub, London, W12 0BZ, UK
| | - David Klenerman
- Department of Chemistry, University of Cambridge, London, CB2 1EW, UK
| | - Elena V Sviderskaya
- Cell Biology Research Centre, Molecular and Clinical Sciences Research Institute, St George's, University of London, London, SW17 0RE, UK.
| | - Joshua B Edel
- Department of Chemistry, Imperial College London, Molecular Science Research Hub, London, W12 0BZ, UK.
| | - Yuri Korchev
- Department of Medicine, Imperial College London, London, W12 0NN, UK.
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan.
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Abstract
BACKGROUND Gastroesophageal reflux disease (GERD) is a common problem in neonates, and current modalities for thickening human milk produce inconsistent outcomes. The objective of this in vitro study is to measure the viscosity effect of different thickening strategies. METHODS We thickened donor human milk (DHM) and formula using various thickeners: starch-based thickeners (SBT; Thick It, rice cereal), and gum-based thickeners (GBT; xanthan gum: Simply Thick, Thicken Up Clear; carob gum: GelMix). We also assessed formula with added starches marketed for reflux, including Similac Spit Up (SSU) and Enfamil AR (EAR). The viscosity of each sample was measured over time using a rotary viscometer. Additional variables, including acidity, temperature, and the addition of human milk fortifier, were tested. RESULTS Formula can be effectively thickened with all tested thickeners, but the viscosities of thickened formula increase over time. On the other hand, DHM does not effectively thicken with SBT. Autoclaving DHM inactivates digestive enzymes, thus allowing SBT to successfully thicken autoclaved DHM. GBT effectively thickened both DHM and formula but reached higher viscosities than intended based on manufacturer recommendations. Adding acid to xanthan-gum thickened DHM resulted in phase separation and formation of solid precipitant. CONCLUSIONS Current thickening strategies of preterm infant feeding produces highly variable results in final feed viscosity. The unpredictable properties of gum-based thickeners raise questions about their safety profile. Objective measures of liquid viscosity and careful consideration of acidity and time are recommended for adequate comparisons of thickening regimens. Human milk continues to be the most challenging feed type to thicken.
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9
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Yao X, Smolka AJ. Gastric Parietal Cell Physiology and Helicobacter pylori-Induced Disease. Gastroenterology 2019; 156:2158-2173. [PMID: 30831083 PMCID: PMC6715393 DOI: 10.1053/j.gastro.2019.02.036] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 02/12/2019] [Accepted: 02/14/2019] [Indexed: 12/13/2022]
Abstract
Acidification of the gastric lumen poses a barrier to transit of potentially pathogenic bacteria and enables activation of pepsin to complement nutrient proteolysis initiated by salivary proteases. Histamine-induced activation of the PKA signaling pathway in gastric corpus parietal cells causes insertion of proton pumps into their apical plasma membranes. Parietal cell secretion and homeostasis are regulated by signaling pathways that control cytoskeletal changes required for apical membrane remodeling and organelle and proton pump activities. Helicobacter pylori colonization of human gastric mucosa affects gastric epithelial cell plasticity and homeostasis, promoting epithelial progression to neoplasia. By intervening in proton pump expression, H pylori regulates the abundance and diversity of microbiota that populate the intestinal lumen. We review stimulation-secretion coupling and renewal mechanisms in parietal cells and the mechanisms by which H pylori toxins and effectors alter cell secretory pathways (constitutive and regulated) and organelles to establish and maintain their inter- and intracellular niches. Studies of bacterial toxins and their effector proteins have provided insights into parietal cell physiology and the mechanisms by which pathogens gain control of cell activities, increasing our understanding of gastrointestinal physiology, microbial infectious disease, and immunology.
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Affiliation(s)
- Xuebiao Yao
- MOE Key Laboratory of Cellular Dynamics, CAS Center for Excellence in Molecular Cell Science, University of Science and Technology of China, Hefei, China; Keck Center for Cellular Dynamics and Organoids Plasticity, Morehouse School of Medicine, Atlanta, Georgia.
| | - Adam J. Smolka
- Gastroenterology and Hepatology Division, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina
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10
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Schlegel C, Weis VG, Knowles BC, Lapierre LA, Martin MG, Dickman P, Goldenring JR, Shub MD. Apical Membrane Alterations in Non-intestinal Organs in Microvillus Inclusion Disease. Dig Dis Sci 2018; 63:356-365. [PMID: 29218485 PMCID: PMC5797493 DOI: 10.1007/s10620-017-4867-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 11/22/2017] [Indexed: 12/09/2022]
Abstract
OBJECTIVES Microvillus inclusion disease (MVID) is a severe form of neonatal diarrhea, caused mainly by mutations in MYO5B. Inactivating mutations in MYO5B causes depolarization of enterocytes in the small intestine, which gives rise to chronic, unremitting secretory diarrhea. While the pathology of the small intestine in MVID patients is well described, little is known about extraintestinal effects of MYO5B mutation. METHODS We examined stomach, liver, pancreas, colon, and kidney in Navajo MVID patients, who share a single homozygous MYO5B-P660L (1979C>T p.Pro660Leu, exon 16). Sections were stained for markers of the apical membrane to assess polarized trafficking. RESULTS Navajo MVID patients showed notable changes in H/K-ATPase-containing tubulovesicle structure in the stomach parietal cells. Colonic mucosa was morphologically normal, but did show losses in apical ezrin and Syntaxin 3. Hepatocytes in the MVID patients displayed aberrant canalicular expression of the essential transporters MRP2 and BSEP. The pancreas showed small fragmented islets and a decrease in apical ezrin in pancreatic ducts. Kidney showed normal primary cilia. CONCLUSIONS These findings indicate that the effects of the P660L mutation in MYO5B in Navajo MVID patients are not limited to the small intestine, but that certain tissues may be able to compensate functionally for alterations in apical trafficking.
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Affiliation(s)
- Cameron Schlegel
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN, USA
- Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Victoria G Weis
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN, USA
- Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Byron C Knowles
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
- Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Lynne A Lapierre
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN, USA
- Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Martin G Martin
- Department of Pediatrics, Division of Gastroenterology and Nutrition, Mattel Children's Hospital, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Paul Dickman
- Division of Pathology and Laboratory Medicine, Phoenix Children's Hospital, Phoenix, AZ, USA
- Department of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA
| | - James R Goldenring
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN, USA.
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA.
- Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA.
| | - Mitchell D Shub
- Division of Gastroenterology, Phoenix Children's Hospital, Phoenix, AZ, USA
- Department of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA
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11
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ASAP3 regulates microvilli structure in parietal cells and presents intervention target for gastric acidity. Signal Transduct Target Ther 2017; 2:17003. [PMID: 29263912 PMCID: PMC5661632 DOI: 10.1038/sigtrans.2017.3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 01/20/2017] [Accepted: 01/22/2017] [Indexed: 01/28/2023] Open
Abstract
Gastric acidity-associated disorders such as peptic ulcer and reflux diseases are widespread, and the reported resistance and side effects of currently used medicines suggest an urgent requirement for alternative therapeutic approaches. Here we demonstrate a critical role of ASAP3 in regulating the microvilli structure of parietal cells in vivo, and reveal the feasibility of controlling gastric acidity by targeting ASAP3. Conditional knockout of ASAP3 in mice caused elongation and stacking of microvilli in parietal cells, and substantially decreased gastric acid secretion. These were associated with active assembly of F-actin caused by a higher level of GTP-bound Arf6 GTPase. Consistently, a small molecular compound QS11 inhibited ASAP3 function and significantly reduced gastric acidity in vivo. Of note, the expression of ASAP3 was positively correlated with gastric acid secretion in 90 human cases, and high expression of ASAP3 was associated with reflux disease and peptic ulcer. These results reveal for the first time that ASAP3 regulates the microvilli structures in parietal cells. Our data also suggest ASAP3 as a feasible and drugable therapeutic target for gastric acidity-associated diseases.
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12
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Sahoo N, Gu M, Zhang X, Raval N, Yang J, Bekier M, Calvo R, Patnaik S, Wang W, King G, Samie M, Gao Q, Sahoo S, Sundaresan S, Keeley TM, Wang Y, Marugan J, Ferrer M, Samuelson LC, Merchant JL, Xu H. Gastric Acid Secretion from Parietal Cells Is Mediated by a Ca 2+ Efflux Channel in the Tubulovesicle. Dev Cell 2017; 41:262-273.e6. [PMID: 28486130 DOI: 10.1016/j.devcel.2017.04.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 03/10/2017] [Accepted: 04/03/2017] [Indexed: 12/12/2022]
Abstract
Gastric acid secretion by parietal cells requires trafficking and exocytosis of H/K-ATPase-rich tubulovesicles (TVs) toward apical membranes in response to histamine stimulation via cyclic AMP elevation. Here, we found that TRPML1 (ML1), a protein that is mutated in type IV mucolipidosis (ML-IV), is a tubulovesicular channel essential for TV exocytosis and acid secretion. Whereas ML-IV patients are reportedly achlorhydric, transgenic overexpression of ML1 in mouse parietal cells induced constitutive acid secretion. Gastric acid secretion was blocked and stimulated by ML1 inhibitors and agonists, respectively. Organelle-targeted Ca2+ imaging and direct patch-clamping of apical vacuolar membranes revealed that ML1 mediates a PKA-activated conductance on TV membranes that is required for histamine-induced Ca2+ release from TV stores. Hence, we demonstrated that ML1, acting as a Ca2+ channel in TVs, links transmitter-initiated cyclic nucleotide signaling with Ca2+-dependent TV exocytosis in parietal cells, providing a regulatory mechanism that could be targeted to manage acid-related gastric diseases.
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Affiliation(s)
- Nirakar Sahoo
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, MI 48109, USA
| | - Mingxue Gu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, MI 48109, USA
| | - Xiaoli Zhang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, MI 48109, USA
| | - Neel Raval
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, MI 48109, USA
| | - Junsheng Yang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, MI 48109, USA; Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, China
| | - Michael Bekier
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, MI 48109, USA
| | - Raul Calvo
- National Center for Advancing Translational Sciences, National Institute of Health, 9800 Medical Center Drive, Rockville, MD 20850, USA
| | - Samarjit Patnaik
- National Center for Advancing Translational Sciences, National Institute of Health, 9800 Medical Center Drive, Rockville, MD 20850, USA
| | - Wuyang Wang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, MI 48109, USA
| | - Greyson King
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, MI 48109, USA
| | - Mohammad Samie
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, MI 48109, USA
| | - Qiong Gao
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, MI 48109, USA
| | - Sasmita Sahoo
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, MI 48109, USA
| | - Sinju Sundaresan
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Theresa M Keeley
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yanzhuang Wang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, MI 48109, USA
| | - Juan Marugan
- National Center for Advancing Translational Sciences, National Institute of Health, 9800 Medical Center Drive, Rockville, MD 20850, USA
| | - Marc Ferrer
- National Center for Advancing Translational Sciences, National Institute of Health, 9800 Medical Center Drive, Rockville, MD 20850, USA
| | - Linda C Samuelson
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Juanita L Merchant
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Haoxing Xu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, MI 48109, USA.
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13
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Shashikanth N, Yeruva S, Ong MLDM, Odenwald MA, Pavlyuk R, Turner JR. Epithelial Organization: The Gut and Beyond. Compr Physiol 2017; 7:1497-1518. [DOI: 10.1002/cphy.c170003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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14
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Kitay AM, Geibel JP. Stomach and Bone. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1033:97-131. [DOI: 10.1007/978-3-319-66653-2_6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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15
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Inatomi N, Matsukawa J, Sakurai Y, Otake K. Potassium-competitive acid blockers: Advanced therapeutic option for acid-related diseases. Pharmacol Ther 2016; 168:12-22. [PMID: 27514776 DOI: 10.1016/j.pharmthera.2016.08.001] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 07/29/2016] [Indexed: 02/07/2023]
Abstract
Acid-related diseases (ARDs), such as peptic ulcers and gastroesophageal reflux disease, represent a major health-care concern. Some major milestones in our understanding of gastric acid secretion and ARD treatment reached during the last 50years include 1) discovery of histamine H2-receptors and development of H2-receptor antagonists, 2) identification of H+,K+-ATPase as the parietal cell proton pump and development of proton pump inhibitors (PPIs), and 3) identification of Helicobacter pylori (H. pylori) as the major cause of peptic ulcers and development of effective eradication regimens. Although PPI treatments have been effective and successful, there are limitations to their efficacy and usage, i.e. short half-life, insufficient acid suppression, slow onset of action, and large variation in efficacy among patients due to CYP2C19 metabolism. Potassium-competitive acid blockers (P-CABs) inhibit H+,K+-ATPase in a reversible and K+-competitive manner, and exhibit almost complete inhibition of gastric acid secretion from the first dose. Many pharmaceutical companies have tried to develop P-CABs, but most of their clinical development has been discontinued due to safety concerns or a similar efficacy to PPIs. Revaprazan was developed in Korea and was the first P-CAB approved for sale. Vonoprazan, approved in 2014 in Japan, has a completely different chemical structure and higher pKa value compared to other P-CABs, and exhibits rapid onset of action and prolonged control of intragastric acidity. Vonoprazan is an effective treatment for ARDs that is especially effective in healing reflux esophagitis and for H. pylori eradication. P-CABs, such as vonoprazan, promise to further improve the management of ARDs.
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Affiliation(s)
- Nobuhiro Inatomi
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa 251-8555, Japan
| | - Jun Matsukawa
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa 251-8555, Japan.
| | - Yuuichi Sakurai
- Japan Development Center, Takeda Pharmaceutical Company Limited, Chuo-ku, Osaka 540-8645, Japan
| | - Kazuyoshi Otake
- Global Medical Affairs Japan Department, Takeda Pharmaceutical Company Limited, Chuo-ku, Tokyo 103-8668, Japan
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16
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Cuppoletti J. A dynamic and integrated model of gastric HCl secretion: Focus on "Computer modeling of gastric parietal cell: significance of canalicular space, gland lumen, and variable canalicular [K+]". Am J Physiol Gastrointest Liver Physiol 2016; 310:G669-70. [PMID: 26999806 DOI: 10.1152/ajpgi.00100.2016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 03/10/2016] [Indexed: 01/31/2023]
Affiliation(s)
- John Cuppoletti
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio
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17
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Dekkers BL, Kolodziejczyk E, Acquistapace S, Engmann J, Wooster TJ. Impact of gastric pH profiles on the proteolytic digestion of mixed βlg-Xanthan biopolymer gels. Food Funct 2016; 7:58-68. [DOI: 10.1039/c5fo01085c] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Gastric pH profile duringin vitrogastric digestion is critical for proper assessment of mixed biopolymer gel proteolysis.
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Affiliation(s)
| | | | | | - J. Engmann
- Nestec S.A
- Nestlé Research Centre
- CH 1000 Switzerland
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18
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Nighot MP, Nighot PK, Ma TY, Malinowska DH, Shull GE, Cuppoletti J, Blikslager AT. Genetic Ablation of the ClC-2 Cl- Channel Disrupts Mouse Gastric Parietal Cell Acid Secretion. PLoS One 2015; 10:e0138174. [PMID: 26378782 PMCID: PMC4574764 DOI: 10.1371/journal.pone.0138174] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 08/27/2015] [Indexed: 11/30/2022] Open
Abstract
The present studies were designed to examine the effects of ClC-2 ablation on cellular morphology, parietal cell abundance, H/K ATPase expression, parietal cell ultrastructure and acid secretion using WT and ClC-2-/- mouse stomachs. Cellular histology, morphology and proteins were examined using imaging techniques, electron microscopy and western blot. The effect of histamine on the pH of gastric contents was measured. Acid secretion was also measured using methods and secretagogues previously established to give maximal acid secretion and morphological change. Compared to WT, ClC-2-/- gastric mucosal histological organization appeared disrupted, including dilation of gastric glands, shortening of the gastric gland region and disorganization of all cell layers. Parietal cell numbers and H/K ATPase expression were significantly reduced by 34% (P<0.05) and 53% (P<0.001) respectively and cytoplasmic tubulovesicles appeared markedly reduced on electron microscopic evaluation without evidence of canalicular expansion. In WT parietal cells, ClC-2 was apparent in a similar cellular location as the H/K ATPase by immunofluorescence and appeared associated with tubulovesicles by immunogold electron microscopy. Histamine-stimulated [H+] of the gastric contents was significantly (P<0.025) lower by 9.4 fold (89%) in the ClC-2-/- mouse compared to WT. Histamine/carbachol stimulated gastric acid secretion was significantly reduced (range 84–95%, P<0.005) in ClC-2-/- compared to WT, while pepsinogen secretion was unaffected. Genetic ablation of ClC-2 resulted in reduced gastric gland region, reduced parietal cell number, reduced H/K ATPase, reduced tubulovesicles and reduced stimulated acid secretion.
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Affiliation(s)
- Meghali P. Nighot
- North Carolina State University, College of Veterinary Medicine, Raleigh, North Carolina, United States of America
| | - Prashant K. Nighot
- North Carolina State University, College of Veterinary Medicine, Raleigh, North Carolina, United States of America
| | - Thomas Y. Ma
- University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
| | - Danuta H. Malinowska
- University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Gary E. Shull
- University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - John Cuppoletti
- University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Anthony T. Blikslager
- North Carolina State University, College of Veterinary Medicine, Raleigh, North Carolina, United States of America
- * E-mail:
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19
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Yuan J, Liu W, Karvar S, Baker SS, He W, Baker RD, Ji G, Xie J, Zhu L. Potassium channel KCNJ15 is required for histamine-stimulated gastric acid secretion. Am J Physiol Cell Physiol 2015; 309:C264-70. [DOI: 10.1152/ajpcell.00012.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 06/17/2015] [Indexed: 12/14/2022]
Abstract
Gastric acid secretion is mediated by the K+-dependent proton pump (H+,K+-ATPase), which requires a continuous supply of K+ at the luminal side of the apical membrane. Several K+ channels are implicated in gastric acid secretion. However, the identity of the K+ channel(s) responsible for apical K+ supply is still elusive. Our previous studies have shown the translocation of KCNJ15 from cytoplasmic vesicles to the apical membrane on stimulation, indicating its involvement in gastric acid secretion. In this study, the stimulation associated trafficking of KCNJ15 was observed in a more native context with a live cell imaging system. KCNJ15 molecules in resting live cells were scattered in cytoplasm but exhibited apical localization after stimulation. Furthermore, knocking down KCNJ15 expression with a short hairpin RNA adenoviral construct abolished histamine-stimulated acid secretion in rabbit primary parietal cells. Moreover, KCNJ15, like H+,K+-ATPase, was detected in all of the parietal cells by immunofluorescence staining, whereas only about half of the parietal cells were positive for KCNQ1 under the same condition. Consistently, the endogenous protein levels of KCNJ15, analyzed by Western blotting, were higher than those of KCNQ1 in the gastric mucosa of human, mouse, and rabbit. These results provide evidence for a major role of KCNJ15 in apical K+ supply during stimulated acid secretion.
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Affiliation(s)
- Jianye Yuan
- Institute of Digestive Diseases, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Wensheng Liu
- Digestive Diseases and Nutrition Center, Department of Pediatrics, State University of New York at Buffalo, Buffalo, New York; and
| | - Serhan Karvar
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - Susan S. Baker
- Digestive Diseases and Nutrition Center, Department of Pediatrics, State University of New York at Buffalo, Buffalo, New York; and
| | - Wenjun He
- Digestive Diseases and Nutrition Center, Department of Pediatrics, State University of New York at Buffalo, Buffalo, New York; and
| | - Robert D. Baker
- Digestive Diseases and Nutrition Center, Department of Pediatrics, State University of New York at Buffalo, Buffalo, New York; and
| | - Guang Ji
- Institute of Digestive Diseases, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jianqun Xie
- Institute of Digestive Diseases, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Lixin Zhu
- Institute of Digestive Diseases, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
- Digestive Diseases and Nutrition Center, Department of Pediatrics, State University of New York at Buffalo, Buffalo, New York; and
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20
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Watson RL, Buck J, Levin LR, Winger RC, Wang J, Arase H, Muller WA. Endothelial CD99 signals through soluble adenylyl cyclase and PKA to regulate leukocyte transendothelial migration. ACTA ACUST UNITED AC 2015; 212:1021-41. [PMID: 26101266 PMCID: PMC4493416 DOI: 10.1084/jem.20150354] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 05/14/2015] [Indexed: 12/30/2022]
Abstract
CD99 is a critical regulator of leukocyte transendothelial migration (TEM). Watson et al. describe the CD99 signaling pathway responsible. This involves a complex of CD99 with the A-kinase anchoring protein ezrin and soluble adenylyl cyclase that activates protein kinase A during leukocyte TEM. CD99 is a critical regulator of leukocyte transendothelial migration (TEM). How CD99 signals during this process remains unknown. We show that during TEM, endothelial cell (EC) CD99 activates protein kinase A (PKA) via a signaling complex formed with the lysine-rich juxtamembrane cytoplasmic tail of CD99, the A-kinase anchoring protein ezrin, and soluble adenylyl cyclase (sAC). PKA then stimulates membrane trafficking from the lateral border recycling compartment to sites of TEM, facilitating the passage of leukocytes across the endothelium. Pharmacologic or genetic inhibition of EC sAC or PKA, like CD99 blockade, arrests neutrophils and monocytes partway through EC junctions, in vitro and in vivo, without affecting leukocyte adhesion or the expression of relevant cellular adhesion molecules. This is the first description of the CD99 signaling pathway in TEM as well as the first demonstration of a role for sAC in leukocyte TEM.
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Affiliation(s)
- Richard L Watson
- Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60208
| | - Jochen Buck
- Department of Pharmacology, Weill Medical College of Cornell University, New York, NY 10065
| | - Lonny R Levin
- Department of Pharmacology, Weill Medical College of Cornell University, New York, NY 10065
| | - Ryan C Winger
- Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60208
| | - Jing Wang
- Laboratory of Immunochemistry, WPI Immunology Frontier Research Center and Department of Immunochemistry, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Hisashi Arase
- Laboratory of Immunochemistry, WPI Immunology Frontier Research Center and Department of Immunochemistry, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - William A Muller
- Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60208
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21
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Stumpp M, Hu MY, Tseng YC, Guh YJ, Chen YC, Yu JK, Su YH, Hwang PP. Evolution of extreme stomach pH in bilateria inferred from gastric alkalization mechanisms in basal deuterostomes. Sci Rep 2015; 5:10421. [PMID: 26051042 PMCID: PMC4458843 DOI: 10.1038/srep10421] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 04/13/2015] [Indexed: 12/13/2022] Open
Abstract
The stomachs of most vertebrates operate at an acidic pH of 2 generated by the gastric H+/K+-ATPase located in parietal cells. The acidic pH in stomachs of vertebrates is believed to aid digestion and to protect against environmental pathogens. Little attention has been placed on whether acidic gastric pH regulation is a vertebrate character or a deuterostome ancestral trait. Here, we report alkaline conditions up to pH 10.5 in the larval digestive systems of ambulacraria (echinoderm + hemichordate), the closest relative of the chordate. Microelectrode measurements in combination with specific inhibitors for acid-base transporters and ion pumps demonstrated that the gastric alkalization machinery in sea urchin larvae is mainly based on direct H+ secretion from the stomach lumen and involves a conserved set of ion pumps and transporters. Hemichordate larvae additionally utilized HCO3− transport pathways to generate even more alkaline digestive conditions. Molecular analyses in combination with acidification experiments supported these findings and identified genes coding for ion pumps energizing gastric alkalization. Given that insect larval guts were also reported to be alkaline, our discovery raises the hypothesis that the bilaterian ancestor utilized alkaline digestive system while the vertebrate lineage has evolved a strategy to strongly acidify their stomachs.
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Affiliation(s)
- Meike Stumpp
- 1] Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan R.O.C. [2] Helmholtz Centre for Ocean Research Kiel (GEOMAR), Kiel, Germany
| | - Marian Y Hu
- 1] Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan R.O.C. [2] Institute of Physiology, Christian Albrechts University Kiel, Kiel, Germany
| | - Yung-Che Tseng
- Department of Life Sciences, National Taiwan Normal University, Taipei, Taiwan R.O.C
| | - Ying-Jeh Guh
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan R.O.C
| | - Yi-Chih Chen
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan R.O.C
| | - Jr-Kai Yu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan R.O.C
| | - Yi-Hsien Su
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan R.O.C
| | - Pung-Pung Hwang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan R.O.C
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22
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Wang J, Barbuskaite D, Tozzi M, Giannuzzo A, Sørensen CE, Novak I. Proton Pump Inhibitors Inhibit Pancreatic Secretion: Role of Gastric and Non-Gastric H+/K+-ATPases. PLoS One 2015; 10:e0126432. [PMID: 25993003 PMCID: PMC4436373 DOI: 10.1371/journal.pone.0126432] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 04/02/2015] [Indexed: 02/07/2023] Open
Abstract
The mechanism by which pancreas secretes high HCO3- has not been fully resolved. This alkaline secretion, formed in pancreatic ducts, can be achieved by transporting HCO3- from serosa to mucosa or by moving H+ in the opposite direction. The aim of the present study was to determine whether H+/K+-ATPases are expressed and functional in human pancreatic ducts and whether proton pump inhibitors (PPIs) have effect on those. Here we show that the gastric HKα1 and HKβ subunits (ATP4A; ATP4B) and non-gastric HKα2 subunits (ATP12A) of H+/K+-ATPases are expressed in human pancreatic cells. Pumps have similar localizations in duct cell monolayers (Capan-1) and human pancreas, and notably the gastric pumps are localized on the luminal membranes. In Capan-1 cells, PPIs inhibited recovery of intracellular pH from acidosis. Furthermore, in rats treated with PPIs, pancreatic secretion was inhibited but concentrations of major ions in secretion follow similar excretory curves in control and PPI treated animals. In addition to HCO3-, pancreas also secretes K+. In conclusion, this study calls for a revision of the basic model for HCO3- secretion. We propose that proton transport is driving secretion, and that in addition it may provide a protective pH buffer zone and K+ recirculation. Furthermore, it seems relevant to re-evaluate whether PPIs should be used in treatment therapies where pancreatic functions are already compromised.
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Affiliation(s)
- Jing Wang
- Department of Biology, Section for Molecular Integrative Physiology, August Krogh Building, University of Copenhagen, Copenhagen, Denmark
| | - Dagne Barbuskaite
- Department of Biology, Section for Molecular Integrative Physiology, August Krogh Building, University of Copenhagen, Copenhagen, Denmark
| | - Marco Tozzi
- Department of Biology, Section for Molecular Integrative Physiology, August Krogh Building, University of Copenhagen, Copenhagen, Denmark
| | - Andrea Giannuzzo
- Department of Biology, Section for Molecular Integrative Physiology, August Krogh Building, University of Copenhagen, Copenhagen, Denmark
| | - Christiane E. Sørensen
- Department of Biology, Section for Molecular Integrative Physiology, August Krogh Building, University of Copenhagen, Copenhagen, Denmark
| | - Ivana Novak
- Department of Biology, Section for Molecular Integrative Physiology, August Krogh Building, University of Copenhagen, Copenhagen, Denmark
- * E-mail:
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23
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Sachs G, Shin JM, Munson K, Scott DR. Gastric acid-dependent diseases: a twentieth-century revolution. Dig Dis Sci 2014; 59:1358-69. [PMID: 24852882 DOI: 10.1007/s10620-014-3104-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- George Sachs
- Department of Medicine, David Geffen School of Medicine, The Veterans Administration Greater Los Angeles Healthcare System, University of California at Los Angeles, Bldg 113, Rm 324 11301 Wilshire Blvd., Los Angeles, CA, 90073, USA,
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24
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Natarajan P, Crothers JM, Rosen JE, Nakada SL, Rakholia M, Okamoto CT, Forte JG, Machen TE. Myosin IIB and F-actin control apical vacuolar morphology and histamine-induced trafficking of H-K-ATPase-containing tubulovesicles in gastric parietal cells. Am J Physiol Gastrointest Liver Physiol 2014; 306:G699-710. [PMID: 24578340 PMCID: PMC3989701 DOI: 10.1152/ajpgi.00316.2013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Selective inhibitors of myosin or actin function and confocal microscopy were used to test the role of an actomyosin complex in controlling morphology, trafficking, and fusion of tubulovesicles (TV) containing H-K-ATPase with the apical secretory canaliculus (ASC) of primary-cultured rabbit gastric parietal cells. In resting cells, myosin IIB and IIC, ezrin, and F-actin were associated with ASC, whereas H-K-ATPase localized to intracellular TV. Histamine caused fusion of TV with ASC and subsequent expansion resulting from HCl and water secretion; F-actin and ezrin remained associated with ASC whereas myosin IIB and IIC appeared to dissociate from ASC and relocalize to the cytoplasm. ML-7 (inhibits myosin light chain kinase) caused ASC of resting cells to collapse and most myosin IIB, F-actin, and ezrin to dissociate from ASC. TV were unaffected by ML-7. Jasplakinolide (stabilizes F-actin) caused ASC to develop large blebs to which actin, myosin II, and ezrin, as well as tubulin, were prominently localized. When added prior to stimulation, ML-7 and jasplakinolide prevented normal histamine-stimulated transformations of ASC/TV and the cytoskeleton, but they did not affect cells that had been previously stimulated with histamine. These results indicate that dynamic pools of actomyosin are required for maintenance of ASC structure in resting cells and for trafficking of TV to ASC during histamine stimulation. However, the dynamic pools of actomyosin are not required once the histamine-stimulated transformation of TV/ASC and cytoskeleton has occurred. These results also show that vesicle trafficking in parietal cells shares mechanisms with similar processes in renal collecting duct cells, neuronal synapses, and skeletal muscle.
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Affiliation(s)
- Paramasivam Natarajan
- 1Department of Molecular and Cell Biology, University of California, Berkeley, California; and
| | - James M. Crothers
- 1Department of Molecular and Cell Biology, University of California, Berkeley, California; and
| | - Jared E. Rosen
- 1Department of Molecular and Cell Biology, University of California, Berkeley, California; and
| | - Stephanie L. Nakada
- 1Department of Molecular and Cell Biology, University of California, Berkeley, California; and
| | - Milap Rakholia
- 1Department of Molecular and Cell Biology, University of California, Berkeley, California; and
| | - Curtis T. Okamoto
- 2Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California
| | - John G. Forte
- 1Department of Molecular and Cell Biology, University of California, Berkeley, California; and
| | - Terry E. Machen
- 1Department of Molecular and Cell Biology, University of California, Berkeley, California; and
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25
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Truchet S, Chat S, Ollivier-Bousquet M. Milk secretion: The role of SNARE proteins. J Mammary Gland Biol Neoplasia 2014; 19:119-30. [PMID: 24264376 DOI: 10.1007/s10911-013-9311-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 11/13/2013] [Indexed: 12/21/2022] Open
Abstract
During lactation, polarized mammary epithelial secretory cells (MESCs) secrete huge quantities of the nutrient molecules that make up milk, i.e. proteins, fat globules and soluble components such as lactose and minerals. Some of these nutrients are only produced by the MESCs themselves, while others are to a great extent transferred from the blood. MESCs can thus be seen as a crossroads for both the uptake and the secretion with cross-talks between intracellular compartments that enable spatial and temporal coordination of the secretion of the milk constituents. Although the physiology of lactation is well understood, the molecular mechanisms underlying the secretion of milk components remain incompletely characterized. Major milk proteins, namely caseins, are secreted by exocytosis, while the milk fat globules are released by budding, being enwrapped by the apical plasma membrane. Prolactin, which stimulates the transcription of casein genes, also induces the production of arachidonic acid, leading to accelerated casein transport and/or secretion. Because of their ability to form complexes that bridge two membranes and promote their fusion, SNARE (Soluble N-ethylmaleimide-Sensitive Factor Attachment Protein Receptor) proteins are involved in almost all intracellular trafficking steps and exocytosis. As SNAREs can bind arachidonic acid, they could be the effectors of the secretagogue effect of prolactin in MESCs. Indeed, some SNAREs have been observed between secretory vesicles and lipid droplets suggesting that these proteins could not only orchestrate the intracellular trafficking of milk components but also act as key regulators for both the coupling and coordination of milk product secretion in response to hormones.
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Affiliation(s)
- Sandrine Truchet
- INRA, UR1196 Génomique et Physiologie de la Lactation, 78352, Jouy-en-Josas Cedex, France,
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26
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Novak I, Haanes KA, Wang J. Acid-base transport in pancreas-new challenges. Front Physiol 2013; 4:380. [PMID: 24391597 PMCID: PMC3868914 DOI: 10.3389/fphys.2013.00380] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 12/04/2013] [Indexed: 12/11/2022] Open
Abstract
Along the gastrointestinal tract a number of epithelia contribute with acid or basic secretions in order to aid digestive processes. The stomach and pancreas are the most extreme examples of acid (H(+)) and base (HCO(-) 3) transporters, respectively. Nevertheless, they share the same challenges of transporting acid and bases across epithelia and effectively regulating their intracellular pH. In this review, we will make use of comparative physiology to enlighten the cellular mechanisms of pancreatic HCO(-) 3 and fluid secretion, which is still challenging physiologists. Some of the novel transporters to consider in pancreas are the proton pumps (H(+)-K(+)-ATPases), as well as the calcium-activated K(+) and Cl(-) channels, such as KCa3.1 and TMEM16A/ANO1. Local regulators, such as purinergic signaling, fine-tune, and coordinate pancreatic secretion. Lastly, we speculate whether dys-regulation of acid-base transport contributes to pancreatic diseases including cystic fibrosis, pancreatitis, and cancer.
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Affiliation(s)
- Ivana Novak
- Department of Biology, University of Copenhagen Copenhagen, Denmark
| | | | - Jing Wang
- Department of Biology, University of Copenhagen Copenhagen, Denmark
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Pedersen SF, Hoffmann EK, Novak I. Cell volume regulation in epithelial physiology and cancer. Front Physiol 2013; 4:233. [PMID: 24009588 PMCID: PMC3757443 DOI: 10.3389/fphys.2013.00233] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Accepted: 08/09/2013] [Indexed: 12/21/2022] Open
Abstract
The physiological function of epithelia is transport of ions, nutrients, and fluid either in secretory or absorptive direction. All of these processes are closely related to cell volume changes, which are thus an integrated part of epithelial function. Transepithelial transport and cell volume regulation both rely on the spatially and temporally coordinated function of ion channels and transporters. In healthy epithelia, specific ion channels/transporters localize to the luminal and basolateral membranes, contributing to functional epithelial polarity. In pathophysiological processes such as cancer, transepithelial and cell volume regulatory ion transport are dys-regulated. Furthermore, epithelial architecture and coordinated ion transport function are lost, cell survival/death balance is altered, and new interactions with the stroma arise, all contributing to drug resistance. Since altered expression of ion transporters and channels is now recognized as one of the hallmarks of cancer, it is timely to consider this especially for epithelia. Epithelial cells are highly proliferative and epithelial cancers, carcinomas, account for about 90% of all cancers. In this review we will focus on ion transporters and channels with key physiological functions in epithelia and known roles in the development of cancer in these tissues. Their roles in cell survival, cell cycle progression, and development of drug resistance in epithelial cancers will be discussed.
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Affiliation(s)
- Stine F Pedersen
- Department of Biology, University of Copenhagen Copenhagen, Denmark
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Vandenberg LN, Morrie RD, Seebohm G, Lemire JM, Levin M. Rab GTPases are required for early orientation of the left-right axis in Xenopus. Mech Dev 2013; 130:254-71. [PMID: 23354119 PMCID: PMC10676213 DOI: 10.1016/j.mod.2012.11.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 11/14/2012] [Accepted: 11/16/2012] [Indexed: 02/04/2023]
Abstract
The earliest steps of left-right (LR) patterning in Xenopus embryos are driven by biased intracellular transport that ensures a consistently asymmetric localization of maternal ion channels and pumps in the first 2-4 blastomeres. The subsequent differential net efflux of ions by these transporters generates a bioelectrical asymmetry; this LR voltage gradient redistributes small signaling molecules along the LR axis that later regulate transcription of the normally left-sided Nodal. This system thus amplifies single cell chirality into a true left-right asymmetry across multi-cellular fields. Studies using molecular-genetic gain- and loss-of-function reagents have characterized many of the steps involved in this early pathway in Xenopus. Yet one key question remains: how is the chiral cytoskeletal architecture interpreted to localize ion transporters to the left or right side? Because Rab GTPases regulate nearly all aspects of membrane trafficking, we hypothesized that one or more Rab proteins were responsible for the directed, asymmetric shuttling of maternal ion channel or pump proteins. After performing a screen using dominant negative and wildtype (overexpressing) mRNAs for four different Rabs, we found that alterations in Rab11 expression randomize both asymmetric gene expression and organ situs. We also demonstrated that the asymmetric localization of two ion transporter subunits requires Rab11 function, and that Rab11 is closely associated with at least one of these subunits. Yet, importantly, we found that endogenous Rab11 mRNA and protein are expressed symmetrically in the early embryo. We conclude that Rab11-mediated transport is responsible for the movement of cargo within early blastomeres, and that Rab11 expression is required throughout the early embryo for proper LR patterning.
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Affiliation(s)
- Laura N. Vandenberg
- Center for Regenerative and Developmental Biology, and Biology Department, Tufts University Medford, MA 02155, United States
| | - Ryan D. Morrie
- Center for Regenerative and Developmental Biology, and Biology Department, Tufts University Medford, MA 02155, United States
| | - Guiscard Seebohm
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, Myocellular Electophysiology Group, University Hospital Münster, D-48149 Münster, Germany
| | - Joan M. Lemire
- Center for Regenerative and Developmental Biology, and Biology Department, Tufts University Medford, MA 02155, United States
| | - Michael Levin
- Center for Regenerative and Developmental Biology, and Biology Department, Tufts University Medford, MA 02155, United States
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Kopic S, Geibel JP. Gastric acid, calcium absorption, and their impact on bone health. Physiol Rev 2013; 93:189-268. [PMID: 23303909 DOI: 10.1152/physrev.00015.2012] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Calcium balance is essential for a multitude of physiological processes, ranging from cell signaling to maintenance of bone health. Adequate intestinal absorption of calcium is a major factor for maintaining systemic calcium homeostasis. Recent observations indicate that a reduction of gastric acidity may impair effective calcium uptake through the intestine. This article reviews the physiology of gastric acid secretion, intestinal calcium absorption, and their respective neuroendocrine regulation and explores the physiological basis of a potential link between these individual systems.
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Affiliation(s)
- Sascha Kopic
- Department of Surgery and Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut, USA
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30
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Nguyen N, Kozer-Gorevich N, Gliddon BL, Smolka AJ, Clayton AH, Gleeson PA, van Driel IR. Independent trafficking of the KCNQ1 K+ channel and H+-K+-ATPase in gastric parietal cells from mice. Am J Physiol Gastrointest Liver Physiol 2013; 304:G157-66. [PMID: 23154976 DOI: 10.1152/ajpgi.00346.2012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Gastric acid secretion by the H(+)-K(+)-ATPase at the apical surface of activated parietal cells requires luminal K(+) provided by the KCNQ1/KCNE2 K(+) channel. However, little is known about the trafficking and relative spatial distribution of KCNQ1 and H(+)-K(+)-ATPase in resting and activated parietal cells and the capacity of KCNQ1 to control acid secretion. Here we show that inhibition of KCNQ1 activity quickly curtails gastric acid secretion in vivo, even when the H(+)-K(+)-ATPase is permanently anchored in the apical membrane, demonstrating a key role of the K(+) channel in controlling acid secretion. Three-dimensional imaging analysis of isolated mouse gastric units revealed that the majority of KCNQ1 resides in an intracytoplasmic, Rab11-positive compartment in resting parietal cells, distinct from H(+)-K(+)-ATPase-enriched tubulovesicles. Upon activation, there was a significant redistribution of H(+)-K(+)-ATPase and KCNQ1 from intracytoplasmic compartments to the apical secretory canaliculi. Significantly, high Förster resonance energy transfer was detected between H(+)-K(+)-ATPase and KCNQ1 in activated, but not resting, parietal cells. These findings demonstrate that H(+)-K(+)-ATPase and KCNQ1 reside in independent intracytoplasmic membrane compartments, or membrane domains, and upon activation of parietal cells, both membrane proteins are transported, possibly via Rab11-positive recycling endosomes, to apical membranes, where the two molecules are closely physically opposed. In addition, these studies indicate that acid secretion is regulated by independent trafficking of KCNQ1 and H(+)-K(+)-ATPase.
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Affiliation(s)
- Nhung Nguyen
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Australia
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31
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Nakada SL, Crothers JM, Machen TE, Forte JG. Apical vacuole formation by gastric parietal cells in primary culture: effect of low extracellular Ca2+. Am J Physiol Cell Physiol 2012; 303:C1301-11. [PMID: 23099641 DOI: 10.1152/ajpcell.00244.2012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In primary culture, the gastric parietal cell's deeply invaginated apical membrane, seen in microscopy by phalloidin binding to F-actin (concentrated in microvilli and a subapical web), is engulfed into the cell, separated from the basolateral membrane (which then becomes the complete plasma membrane), and converted, from a lacy interconnected system of canaliculi, into several separate vacuoles. In this study, vacuolar morphology was achieved by 71% of parietal cells 8 h after typical collagenase digestion of rabbit gastric mucosa, but the tight-junctional protein zonula occludens-1 (ZO-1) was completely delocalized after ∼2 h, when cells were ready for culturing. Use of low-Ca(2+) medium (4 mM EGTA) to release cells quickly from gastric glands yielded parietal cells in which ZO-1 was seen in a small spot or ring, a localization quickly lost if these cells were then cultured in normal Ca(2+) but remaining up to 20 h if they were cultured in low Ca(2+). The cells in low Ca(2+) mostly retained, at 20 h, an intermediate morphology of many bulbous canalicular expansions ("prevacuoles"), seemingly with narrow interconnections. Histamine stimulation of 20-h cells with intermediate morphology caused colocalization of proton-pumping H-K-ATPase with canaliculi and prevacuoles but little swelling of those structures, consistent with a remaining apical pore through which secreted acid could escape. Apparent canalicular interconnections, lack of stimulated swelling, and lingering ZO-1 staining indicate inhibition of membrane fission processes that separate apical from basolateral membrane and vacuoles from each other, suggesting an important role for extracellular Ca(2+) in these, and possibly other, endocytotic processes.
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Affiliation(s)
- Stephanie L Nakada
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200, USA
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Kasai H, Takahashi N, Tokumaru H. Distinct Initial SNARE Configurations Underlying the Diversity of Exocytosis. Physiol Rev 2012; 92:1915-64. [DOI: 10.1152/physrev.00007.2012] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The dynamics of exocytosis are diverse and have been optimized for the functions of synapses and a wide variety of cell types. For example, the kinetics of exocytosis varies by more than five orders of magnitude between ultrafast exocytosis in synaptic vesicles and slow exocytosis in large dense-core vesicles. However, in all cases, exocytosis is mediated by the same fundamental mechanism, i.e., the assembly of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. It is often assumed that vesicles need to be docked at the plasma membrane and SNARE proteins must be preassembled before exocytosis is triggered. However, this model cannot account for the dynamics of exocytosis recently reported in synapses and other cells. For example, vesicles undergo exocytosis without prestimulus docking during tonic exocytosis of synaptic vesicles in the active zone. In addition, epithelial and hematopoietic cells utilize cAMP and kinases to trigger slow exocytosis of nondocked vesicles. In this review, we summarize the manner in which the diversity of exocytosis reflects the initial configurations of SNARE assembly, including trans-SNARE, binary-SNARE, unitary-SNARE, and cis-SNARE configurations. The initial SNARE configurations depend on the particular SNARE subtype (syntaxin, SNAP25, or VAMP), priming proteins (Munc18, Munc13, CAPS, complexin, or snapin), triggering proteins (synaptotagmins, Doc2, and various protein kinases), and the submembraneous cytomatrix, and they are the key to determining the kinetics of subsequent exocytosis. These distinct initial configurations will help us clarify the common SNARE assembly processes underlying exocytosis and membrane trafficking in eukaryotic cells.
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Affiliation(s)
- Haruo Kasai
- Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; and Faculty of Pharmaceutical Sciences at Kagawa, Tokushima Bunri University, Kagawa, Japan
| | - Noriko Takahashi
- Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; and Faculty of Pharmaceutical Sciences at Kagawa, Tokushima Bunri University, Kagawa, Japan
| | - Hiroshi Tokumaru
- Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; and Faculty of Pharmaceutical Sciences at Kagawa, Tokushima Bunri University, Kagawa, Japan
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Nishi M, Aoyama F, Kisa F, Zhu H, Sun M, Lin P, Ohta H, Van B, Yamamoto S, Kakizawa S, Sakai H, Ma J, Sawaguchi A, Takeshima H. TRIM50 protein regulates vesicular trafficking for acid secretion in gastric parietal cells. J Biol Chem 2012; 287:33523-32. [PMID: 22872646 DOI: 10.1074/jbc.m112.370551] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Of the TRIM/RBCC family proteins taking part in a variety of cellular processes, TRIM50 is a stomach-specific member with no defined biological function. Our biochemical data demonstrated that TRIM50 is specifically expressed in gastric parietal cells and is predominantly localized in the tubulovesicular and canalicular membranes. In cultured cells ectopically expressing GFP-TRIM50, confocal microscopic imaging revealed dynamic movement of TRIM50-associated vesicles in a phosphoinositide 3-kinase-dependent manner. A protein overlay assay detected preferential binding of the PRY-SPRY domain from the TRIM50 C-terminal region to phosphatidylinositol species, suggesting that TRIM50 is involved in vesicular dynamics by sensing the phosphorylated state of phosphoinositol lipids. Trim50 knock-out mice retained normal histology in the gastric mucosa but exhibited impaired secretion of gastric acid. In response to histamine, Trim50 knock-out parietal cells generated deranged canaliculi, swollen microvilli lacking actin filaments, and excess multilamellar membrane complexes. Therefore, TRIM50 seems to play an essential role in tubulovesicular dynamics, promoting the formation of sophisticated canaliculi and microvilli during acid secretion in parietal cells.
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Affiliation(s)
- Miyuki Nishi
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
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The Golgi apparatus in the endomembrane-rich gastric parietal cells exist as functional stable mini-stacks dispersed throughout the cytoplasm. Biol Cell 2012; 103:559-72. [PMID: 21899517 PMCID: PMC3210445 DOI: 10.1042/bc20110074] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Background information. Acid-secreting gastric parietal cells are polarized epithelial cells that harbour highly abundant and specialized, H+,K+ ATPase-containing, tubulovesicular membranes in the apical cytoplasm. The Golgi apparatus has been implicated in the biogenesis of the tubulovesicular membranes; however, an unanswered question is how a typical Golgi organization could regulate normal membrane transport within the membrane-dense cytoplasm of parietal cells. Results. Here, we demonstrate that the Golgi apparatus of parietal cells is not the typical juxta-nuclear ribbon of stacks, but rather individual Golgi units are scattered throughout the cytoplasm. The Golgi membrane structures labelled with markers of both cis- and trans-Golgi membrane, indicating the presence of intact Golgi stacks. The parietal cell Golgi stacks were closely aligned with the microtubule network and were shown to participate in both anterograde and retrograde transport pathways. Dispersed Golgi stacks were also observed in parietal cells from H+,K+ ATPase-deficient mice that lack tubulovesicular membranes. Conclusions. These results indicate that the unusual organization of individual Golgi stacks dispersed throughout the cytoplasm of these terminally differentiated cells is likely to be a developmentally regulated event.
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35
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Quiescent gastric stem cells maintain the adult Drosophila stomach. Proc Natl Acad Sci U S A 2011; 108:17696-701. [PMID: 21984734 DOI: 10.1073/pnas.1109794108] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The adult Drosophila copper cell region or "stomach" is a highly acidic compartment of the midgut with pH < 3. In this region, a specialized group of acid-secreting cells similar to mammalian gastric parietal cells has been identified by a unique ultrastructure and by copper-metallothionein fluorescence. However, the homeostatic mechanism maintaining the acid-secreting "copper cells" of the adult midgut has not been examined. Here, we combine cell lineage tracing and genetic analysis to investigate the mechanism by which the gastric epithelium is maintained. Our investigation shows that a molecularly identifiable population of multipotent, self-renewing gastric stem cells (GSSCs) produces the acid-secreting copper cells, interstitial cells, and enteroendocrine cells of the stomach. Our assays demonstrate that GSSCs are largely quiescent but can be induced to regenerate the gastric epithelium in response to environmental challenge. Finally, genetic analysis reveals that adult GSSC maintenance depends on Wnt signaling. Characterization of the GSSC lineage in Drosophila, with striking similarities to mammals, will advance the study of both homeostatic and pathogenic processes in the stomach.
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Aoyama F, Sawaguchi A. Functional transformation of gastric parietal cells and intracellular trafficking of ion channels/transporters in the apical canalicular membrane associated with acid secretion. Biol Pharm Bull 2011; 34:813-6. [PMID: 21628877 DOI: 10.1248/bpb.34.813] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The parietal cell of the gastric gland is a highly differentiated cell responsible for the gastric hydrochloric acid secretion into the lumen of the stomach. In response to stimulation of acid secretion, the parietal cells undergo well-characterized morphological transformations to recruit H⁺/K⁺-ATPase from the cytoplasmic tubulovesicles to the apical canalicular membrane. Besides H⁺ extrusion via H⁺/K⁺-ATPase, Cl⁻ efflux and K⁺ recycling across the apical canalicular membrane are necessary via chloride and potassium channels/transporters, respectively. In the last decade, a number of molecular candidates for the Cl⁻ efflux and K⁺ recycling have been identified in the apical canalicular membrane of the parietal cell. This review focuses on the functional transformation of gastric parietal cells and intracellular trafficking of ion channels/transporters expressed in the apical canalicular membrane associated with gastric acid secretion.
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Affiliation(s)
- Fumiyo Aoyama
- Department of Anatomy, Ultrastructural Cell Biology, Faculty of Medicine, University of Miyazaki, Kiyotake, Miyazaki, Japan
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37
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He W, Liu W, Chew CS, Baker SS, Baker RD, Forte JG, Zhu L. Acid secretion-associated translocation of KCNJ15 in gastric parietal cells. Am J Physiol Gastrointest Liver Physiol 2011; 301:G591-600. [PMID: 21719736 PMCID: PMC3191558 DOI: 10.1152/ajpgi.00460.2010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Potassium ions are required for gastric acid secretion. Several potassium channels have been implicated in providing K(+) at the apical membrane of parietal cells. In examining the mRNA expression levels between gastric mucosa and liver tissue, KCNJ15 stood out as the most highly specific K(+) channel in the gastric mucosa. Western blot analysis confirmed that KCNJ15 is abundant in the stomach. Immunofluorescence staining of isolated gastric glands indicated that KCNJ15 was expressed in parietal cells and chief cells, but not in mucous neck cells. In resting parietal cells, KCNJ15 was mainly found in puncta throughout the cytoplasm but was distinct from H(+)-K(+)-ATPase. Upon stimulation, KCNJ15 and H(+)-K(+)-ATPase become colocalized on the apical membranes, as suggested by immunofluorescence staining. Western blot analysis of the resting and the stimulated membrane fractions confirmed this observation. From nonsecreting preparations, KCNJ15-containing vesicles sedimented after a 4-h centrifugation at 100,000 g, but not after a 30-min spin, which did sediment most of the H(+)-K(+)-ATPase-containing tubulovesicles. Most of the KCNJ15 containing small vesicle population was depleted upon stimulation of parietal cells, as indicated by the fact that the KCNJ15 signal was shifted to a large membrane fraction that sedimented at 4,000 g. Our results demonstrate that, in nonsecreting parietal cells, KCNJ15 is stored in vesicles distinct from the H(+)-K(+)-ATPase-enriched tubulovesicles. Furthermore, upon stimulation, KCNJ15 and H(+)-K(+)-ATPase both translocate to the apical membrane for active acid secretion. Thus KCNJ15 can be added to the family of apical K(+) channels in gastric parietal cells.
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Affiliation(s)
- Wenjun He
- 1Digestive Diseases and Nutrition Center, Department of Pediatrics, State University of New York at Buffalo, Buffalo, New York;
| | - Wensheng Liu
- 1Digestive Diseases and Nutrition Center, Department of Pediatrics, State University of New York at Buffalo, Buffalo, New York;
| | - Catherine S. Chew
- 2Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, Georgia; and
| | - Susan S. Baker
- 1Digestive Diseases and Nutrition Center, Department of Pediatrics, State University of New York at Buffalo, Buffalo, New York;
| | - Robert D. Baker
- 1Digestive Diseases and Nutrition Center, Department of Pediatrics, State University of New York at Buffalo, Buffalo, New York;
| | - John G. Forte
- 3Department of Molecular and Cell Biology, University of California, Berkeley, California
| | - Lixin Zhu
- 1Digestive Diseases and Nutrition Center, Department of Pediatrics, State University of New York at Buffalo, Buffalo, New York;
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Fujii T, Morii M, Takeguchi N, Sakai H. [Molecular mechanisms of H(+) and Cl(-) secretion in gastric parietal cells]. Nihon Yakurigaku Zasshi 2011; 138:51-5. [PMID: 21828937 DOI: 10.1254/fpj.138.51] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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39
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Neisch AL, Fehon RG. Ezrin, Radixin and Moesin: key regulators of membrane-cortex interactions and signaling. Curr Opin Cell Biol 2011; 23:377-82. [PMID: 21592758 DOI: 10.1016/j.ceb.2011.04.011] [Citation(s) in RCA: 201] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 03/23/2011] [Accepted: 04/19/2011] [Indexed: 12/18/2022]
Abstract
The cell cortex serves as a critical nexus between the extracellular environment/cell membrane and the underlying cytoskeleton and cytoplasm. In many cells, the cell cortex is organized and maintained by the Ezrin, Radixin and Moesin (ERM) proteins, which have the ability to interact with both the plasma membrane and filamentous actin. Although this membrane-cytoskeletal linkage function is critical to stability of the cell cortex, recent studies indicate that this is only a part of what ERMs do in many cells. In addition to their role in binding filamentous actin, ERMs regulate signaling pathways through their ability to bind transmembrane receptors and link them to downstream signaling components. In this review we discuss recent evidence in a variety of cells indicating that ERMs serve as scaffolds to facilitate efficient signal transduction on the cytoplasmic face of the plasma membrane.
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Affiliation(s)
- Amanda L Neisch
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
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40
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Song P, Groos S, Riederer B, Feng Z, Krabbenhöft A, Manns MP, Smolka A, Hagen SJ, Neusch C, Seidler U. Kir4.1 channel expression is essential for parietal cell control of acid secretion. J Biol Chem 2011; 286:14120-8. [PMID: 21367857 DOI: 10.1074/jbc.m110.151191] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Kir4.1 channels were found to colocalize with the H(+)/K(+)-ATPase throughout the parietal cell (PC) acid secretory cycle. This study was undertaken to explore their functional role. Acid secretory rates, electrophysiological parameters, PC ultrastructure, and gene and protein expression were determined in gastric mucosae of 7-8-day-old Kir4.1-deficient mice and WT littermates. Kir4.1(-/-) mucosa secreted significantly more acid and initiated secretion significantly faster than WT mucosa. No change in PC number but a relative up-regulation of H(+)/K(+)-ATPase gene and protein expression (but not of other PC ion transporters) was observed. Electron microscopy revealed fully fused canalicular membranes and a lack of tubulovesicles in resting state Kir4.1(-/-) PCs, suggesting that Kir4.1 ablation may also interfere with tubulovesicle endocytosis. The role of this inward rectifier in the PC apical membrane may therefore be to balance between K(+) loss via KCNQ1/KCNE2 and K(+) reabsorption by the slow turnover of the H(+)/K(+)-ATPase, with consequences for K(+) reabsorption, inhibition of acid secretion, and membrane recycling. Our results demonstrate that Kir4.1 channels are involved in the control of acid secretion and suggest that they may also affect secretory membrane recycling.
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Affiliation(s)
- Penghong Song
- Department of Gastroenterology, Hepatology, and Endocrinology, Hannover Medical School, D-30625 Hannover, Germany
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Selective high-level expression of epsin 3 in gastric parietal cells, where it is localized at endocytic sites of apical canaliculi. Proc Natl Acad Sci U S A 2010; 107:21511-6. [PMID: 21115825 DOI: 10.1073/pnas.1016390107] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Epsin is a ubiquitin-binding endocytic adaptor, which is highly concentrated at clathrin-coated pits and coordinates acquisition of bilayer curvature with coat recruitment and cargo selection. Epsin is encoded by three distinct genes in mammals. Epsin 1 and 2 have broad tissue distribution with high-level expression in the brain. In contrast, epsin 3 was reported to be expressed primarily in immature keratinocytes. Here, we show that epsin 3 is selectively expressed at high levels in the stomach (including the majority of gastric cancers), where it is concentrated in parietal cells. In these cells, epsin 3 is enriched and colocalized with clathrin around apical canaliculi, the sites that control acidification of the stomach lumen via the exo-endocytosis of vesicles containing the H/K ATPase. Deletion of the epsin 3 gene in mice did not result in obvious pathological phenotypes in either the stomach or other organs, possibly because of overlapping functions of the other two epsins. However, levels of EHD1 and EHD2, two membrane tubulating proteins with a role in endocytic recycling, were elevated in epsin 3 knock-out stomachs, pointing to a functional interplay of epsin 3 with EHD proteins in the endocytic pathway of parietal cells. We suggest that epsin 3 cooperates with other bilayer binding proteins with curvature sensing/generating properties in the specialized traffic and membrane remodeling processes typical of gastric parietal cells.
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Abstract
PURPOSE OF REVIEW This review summarizes the past year's literature regarding the regulation of gastric exocrine and endocrine secretion at the central, peripheral, and cellular levels. RECENT FINDINGS Gastric acid secretion is an intricate and dynamic process that is regulated by neural (efferent and afferent), hormonal (e.g., gastrin), and paracrine (e.g., histamine, ghrelin, somatostatin) pathways as well as mechanical (e.g., distension) and chemical (e.g., protein, glutamate, coffee, and ethanol) stimuli. Secretion of hydrochloric acid by the parietal cell involves recruitment and fusion of HK-adenosine triphosphatase (HK-ATPase)-containing cytoplasmic tubulovesicles with the apical membrane with subsequent electroneutral transport of hydronium ions in exchange for potassium; the source of the latter is the potassium channel, KCNQ1. Concomitantly, chloride exits via the cystic fibrosis transmembrane regulator. Inhibition of the HK-ATPase by proton pump inhibitors leads to a compensatory hypergastrinemia which, if prolonged, results in parietal and enterochromaffin-like cell hyperplasia. The clinical consequence is rebound acid secretion which may induce dyspeptic symptoms in healthy individuals and exacerbate reflux symptoms in patients with gastroesophageal reflux disease. SUMMARY We continue to make progress in our understanding of the regulation of gastric acid secretion in health and disease. A better understanding of the pathways and mechanisms regulating acid secretion should lead to improved management of patients with acid-induced disorders as well as those who secrete too little acid.
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Zhu L, Crothers J, Zhou R, Forte JG. A possible mechanism for ezrin to establish epithelial cell polarity. Am J Physiol Cell Physiol 2010; 299:C431-43. [PMID: 20505040 DOI: 10.1152/ajpcell.00090.2010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ezrin is an important membrane/actin cytoskeleton linker protein, especially in epithelia. Ezrin has two important binding domains: an NH(2)-terminal region that binds to plasma membrane and a COOH-terminal region that binds to F-actin only after a conformational activation by phosphorylation at Thr567 of ezrin. The present experiments were undertaken to investigate the detailed cellular changes in the time course of expression of ezrin-T567 mutants (nonphosphorylatable T567A and permanent phospho-mimic T567D) in parietal cells and to assess ezrin distribution and its influence on the elaborate membrane recruitment processes of these cells. T567A mutant and wild-type (WT) ezrin were consistently localized to the apical plasma membrane, even with overexpression. On the other hand, T567D went first to apical membrane at early times and low expression levels, then accumulated mainly at the basal surface after 24 h. Overexpression of WT or T567A led to incorporation of internal membranes to apical vacuoles, while overexpression of T567D led to large incorporation of apical and intracellular membranes (including H-K-ATPase) to the basal surface. Differences in polar distribution of ezrin suggest a role for the linker protein in promoting formation and plasticity of membrane surface projections, forming the basis for a novel theory for ezrin as an organizer and regulator of membrane recruitment. A model simulating the cellular distribution of ezrin and its associated membrane- and F-actin-binding forms is given to predict redistributions observed with phosphorylation and mutant overexpression, and it can easily be modified as more specific information regarding binding constants and specific sites becomes available.
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Affiliation(s)
- Lixin Zhu
- Department of Pediatrics, State University of New York at Buffalo, Buffalo, New York, USA
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