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Khan Z, Mehan S, Saifi MA, Das Gupta G, Narula AS, Kalfin R. Proton Pump Inhibitors and Cognitive Health: Review on Unraveling the Dementia Connection and Co-morbid Risks. Curr Alzheimer Res 2024; 20:739-757. [PMID: 38424433 PMCID: PMC11107432 DOI: 10.2174/0115672050289946240223050737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 01/28/2024] [Accepted: 01/31/2024] [Indexed: 03/02/2024]
Abstract
Dementia, an international health issue distinguished by the impairment of daily functioning due to cognitive decline, currently affects more than 55 million people worldwide, with the majority residing in low-income and middle-income countries. Globally, dementia entails significant economic burdens in 2019, amounting to a cost of 1.3 trillion US dollars. Informal caregivers devote considerable hours to providing care for those affected. Dementia imposes a greater caregiving and disability-adjusted life-year burden on women. A recent study has established a correlation between prolonged Proton Pump Inhibitor (PPI) usage and dementia, in addition to other neurodegenerative conditions. PPIs are frequently prescribed to treat peptic ulcers and GERD (gastroesophageal reflux disease) by decreasing stomach acid secretion. They alleviate acid-related symptoms through the inhibition of acid-secreting H+-K+ ATPase. In a number of observational studies, cognitive decline and dementia in the elderly have been linked to the use of PPIs. The precise mechanism underlying this relationship is unknown. These drugs might also alter the pH of brain cells, resulting in the accumulation of amyloid-beta (Aβ) peptides and the development of Alzheimer's disease (AD). Despite the compelling evidence supporting the association of PPIs with dementia, the results of studies remain inconsistent. The absence of a correlation between PPI use and cognitive decline in some studies emphasizes the need for additional research. Chronic PPI use can conceal underlying conditions, including cancer, celiac disease, vitamin B12 deficiency, and renal injury, highlighting dementia risk and the need for further investigations on cognitive health.
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Affiliation(s)
- Zuber Khan
- Division of Neuroscience, Department of Pharmacology, ISF College of Pharmacy, Moga, Punjab, India (Affiliated to IK Gujral Punjab Technical University), Jalandhar, Punjab, 144603, India;
| | - Sidharth Mehan
- Division of Neuroscience, Department of Pharmacology, ISF College of Pharmacy, Moga, Punjab, India (Affiliated to IK Gujral Punjab Technical University), Jalandhar, Punjab, 144603, India;
| | - Mohd. Anas Saifi
- Department of Medical Elementology and Toxicology, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi-110062, India;
| | - Ghanshyam Das Gupta
- Department of Pharmaceutics, ISF College of Pharmacy, Moga, Punjab, India (Affiliated to IK Gujral Punjab Technical University), Jalandhar, Punjab, 144603, India;
| | - Acharan S. Narula
- Narula Research, LLC, 107 Boulder Bluff, Chapel Hill, NC 27516, USA;
| | - Reni Kalfin
- Institute of Neurobiology, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 23, Sofia 1113, Bulgaria;
- Department of Healthcare, South-West University “NeofitRilski”, Ivan Mihailov St. 66, Blagoevgrad 2700, Bulgaria
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Abdelgied M, Uhl K, Chen OG, Schultz C, Tripp K, Peraino AM, Paithankar S, Chen B, Tamae Kakazu M, Castillo Bahena A, Jager TE, Lawson C, Chesla DW, Pestov N, Modyanov NN, Prokop J, Neubig RR, Uhal BD, Girgis RE, Li X. Targeting ATP12A, a Nongastric Proton Pump α Subunit, for Idiopathic Pulmonary Fibrosis Treatment. Am J Respir Cell Mol Biol 2023; 68:638-650. [PMID: 36780662 PMCID: PMC10257074 DOI: 10.1165/rcmb.2022-0264oc] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 02/13/2023] [Indexed: 02/15/2023] Open
Abstract
Idiopathic pulmonary fibrosis (IPF) is a pathological condition of unknown etiology that results from injury to the lung and an ensuing fibrotic response that leads to the thickening of the alveolar walls and obliteration of the alveolar space. The pathogenesis is not clear, and there are currently no effective therapies for IPF. Small airway disease and mucus accumulation are prominent features in IPF lungs, similar to cystic fibrosis lung disease. The ATP12A gene encodes the α-subunit of the nongastric H+, K+-ATPase, which functions to acidify the airway surface fluid and impairs mucociliary transport function in patients with cystic fibrosis. It is hypothesized that the ATP12A protein may play a role in the pathogenesis of IPF. The authors' studies demonstrate that ATP12A protein is overexpressed in distal small airways from the lungs of patients with IPF compared with normal human lungs. In addition, overexpression of the ATP12A protein in mouse lungs worsened bleomycin induced experimental pulmonary fibrosis. This was prevented by a potassium competitive proton pump blocker, vonoprazan. These data support the concept that the ATP12A protein plays an important role in the pathogenesis of lung fibrosis. Inhibition of the ATP12A protein has potential as a novel therapeutic strategy in IPF treatment.
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Affiliation(s)
| | - Katie Uhl
- Department of Pediatrics and Human Development and
| | | | - Chad Schultz
- Department of Pediatrics and Human Development and
| | - Kaylie Tripp
- Department of Pediatrics and Human Development and
| | | | | | - Bin Chen
- Department of Pediatrics and Human Development and
- Department of Pharmacology and Toxicology and
| | - Maximiliano Tamae Kakazu
- Department of Medicine, College of Human Medicine, Michigan State University, Grand Rapids, Michigan
- Division of Pulmonary and Critical Care Medicine
| | | | - Tara E. Jager
- Richard Devos Heart and Lung Transplant Program, Spectrum Health, Grand Rapids, Michigan
| | - Cameron Lawson
- Richard Devos Heart and Lung Transplant Program, Spectrum Health, Grand Rapids, Michigan
| | | | - Nikolay Pestov
- Department of Physiology and Pharmacology and Center for Diabetes and Endocrine Research, College of Medicine, University of Toledo, Health Science Campus, Toledo, Ohio
| | - Nikolai N. Modyanov
- Department of Physiology and Pharmacology and Center for Diabetes and Endocrine Research, College of Medicine, University of Toledo, Health Science Campus, Toledo, Ohio
| | - Jeremy Prokop
- Department of Pediatrics and Human Development and
- Department of Pharmacology and Toxicology and
| | | | - Bruce D. Uhal
- Department of Physiology, Michigan State University, East Lansing, Michigan; and
| | - Reda E. Girgis
- Department of Medicine, College of Human Medicine, Michigan State University, Grand Rapids, Michigan
- Division of Pulmonary and Critical Care Medicine
- Richard Devos Heart and Lung Transplant Program, Spectrum Health, Grand Rapids, Michigan
| | - Xiaopeng Li
- Department of Pediatrics and Human Development and
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Papazoglou A, Arshaad MI, Henseler C, Daubner J, Broich K, Haenisch B, Weiergräber M. The Janus-like Association between Proton Pump Inhibitors and Dementia. Curr Alzheimer Res 2021; 18:453-469. [PMID: 34587884 PMCID: PMC8778640 DOI: 10.2174/1567205018666210929144740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 06/10/2021] [Accepted: 06/18/2021] [Indexed: 11/30/2022]
Abstract
Early pharmacoepidemiological studies suggested that Proton Pump Inhibitors (PPIs) might increase the risk of Alzheimer’s Disease (AD) and non-AD related dementias. These findings were supported by preclinical studies, specifically stressing the proamyloidogenic and indirect anticholinergic effects of PPIs. However, further large-scale pharmacoepidemiological studies showed inconsistent results on the association between PPIs and dementia. Pharmacodynamically, these findings might be related to the LXR/RXR-mediated amyloid clearance effect and anti-inflammatory action of PPIs. Further aspects that influence PPI effects on AD are related to patient-specific pharmacokinetic and pharmacogenomic characteristics. In conclusion, a personalized (individualized) medicinal approach is necessary to model and predict the potential harmful or beneficial effects of PPIs in AD and non-AD-related dementias in the future.
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Affiliation(s)
- Anna Papazoglou
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany
| | - Muhammad I Arshaad
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany
| | - Christina Henseler
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany
| | - Johanna Daubner
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany
| | - Karl Broich
- Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM) 53127, Kurt-Georg- Kiesinger-Allee 3, 53175 Bonn, Germany
| | - Britta Haenisch
- Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM) 53127, Kurt-Georg- Kiesinger-Allee 3, 53175 Bonn, Germany
| | - Marco Weiergräber
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany
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Fu W, Wang R, Yu J, Hu D, Cai Y, Shao J, Jiang Y. GGVD: A goat genome variation database for tracking the dynamic evolutionary process of selective signatures and ancient introgressions. J Genet Genomics 2021; 48:248-256. [PMID: 33965348 DOI: 10.1016/j.jgg.2021.03.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 03/12/2021] [Accepted: 03/13/2021] [Indexed: 11/20/2022]
Abstract
Understanding the evolutionary history and adaptive process depends on the knowledge that we can acquire from both ancient and modern genomic data. With the availability of a deluge of whole-genome sequencing data from ancient and modern goat samples, a user-friendly database making efficient reuse of these important resources is needed. Here, we use the genomes of 208 modern domestic goats, 24 bezoars, 46 wild ibexes, and 82 ancient goats to present a comprehensive goat genome variation database (GGVD). GGVD hosts a total of ∼41.44 million SNPs, ∼5.14 million indels, 6,193 selected loci, and 112 introgression regions. Users can freely visualize the frequency of genomic variations in geographical maps, selective sweeps in interactive tables, Manhattan plots, or line charts, as well as the heatmap patterns of the SNP genotype. Ancient data can be shown in haplotypes to track the state of genetic variants of selection and introgression events in the early, middle, and late stages. For facilitating access to sequence features, the UCSC Genome Browser, BLAT, BLAST, LiftOver, and pcadapt are also integrated into GGVD. GGVD will be a convenient tool for population genetic studies and molecular marker designing in goat breeding programs, and it is publicly available at http://animal.nwsuaf.edu.cn/GoatVar.
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Affiliation(s)
- Weiwei Fu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Rui Wang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Jiantao Yu
- College of Information Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Dexiang Hu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Yudong Cai
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Junjie Shao
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Yu Jiang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China.
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Ortiz-Guerrero G, Amador-Muñoz D, Calderón-Ospina CA, López-Fuentes D, Nava Mesa MO. Proton Pump Inhibitors and Dementia: Physiopathological Mechanisms and Clinical Consequences. Neural Plast 2018; 2018:5257285. [PMID: 29755512 PMCID: PMC5883984 DOI: 10.1155/2018/5257285] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 02/14/2018] [Indexed: 12/11/2022] Open
Abstract
Alzheimer's disease (AD) is the most common type of dementia, mainly encompassing cognitive decline in subjects aged ≥65 years. Further, AD is characterized by selective synaptic and neuronal degeneration, vascular dysfunction, and two histopathological features: extracellular amyloid plaques composed of amyloid beta peptide (Aβ) and neurofibrillary tangles formed by hyperphosphorylated tau protein. Dementia and AD are chronic neurodegenerative conditions with a complex physiopathology involving both genetic and environmental factors. Recent clinical studies have shown that proton pump inhibitors (PPIs) are associated with risk of dementia, including AD. However, a recent case-control study reported decreased risk of dementia. PPIs are a widely indicated class of drugs for gastric acid-related disorders, although most older adult users are not treated for the correct indication. Although neurological side effects secondary to PPIs are rare, several preclinical reports indicate that PPIs might increase Aβ levels, interact with tau protein, and affect the neuronal microenvironment through several mechanisms. Considering the controversy between PPI use and dementia risk, as well as both cognitive and neuroprotective effects, the aim of this review is to examine the relationship between PPI use and brain effects from a neurobiological and clinical perspective.
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Affiliation(s)
- Gloria Ortiz-Guerrero
- Individualized Research Learner Program, Neuromuscular Research Division, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160, USA
| | - Diana Amador-Muñoz
- Neuroscience (NEUROS) Research Group, School of Medicine and Health Sciences, Universidad del Rosario, Carrera 24 No. 63C–69, Bogotá 111221, Colombia
| | - Carlos Alberto Calderón-Ospina
- Unidad de Farmacología, School of Medicine and Health Sciences, Universidad del Rosario, Carrera 24 No. 63C–69, Bogotá 111221, Colombia
| | - Daniel López-Fuentes
- Medical Social Service, Hospital de San Francisco, Kra 8 No. 6A–121, Gacheta 251230, Colombia
| | - Mauricio Orlando Nava Mesa
- Neuroscience (NEUROS) Research Group, School of Medicine and Health Sciences, Universidad del Rosario, Carrera 24 No. 63C–69, Bogotá 111221, Colombia
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Min JY, Ocampo CJ, Stevens WW, Price CPE, Thompson CF, Homma T, Huang JH, Norton JE, Suh LA, Pothoven KL, Conley DB, Welch KC, Shintani-Smith S, Peters AT, Grammer LC, Harris KE, Hulse KE, Kato A, Modyanov NN, Kern RC, Schleimer RP, Tan BK. Proton pump inhibitors decrease eotaxin-3/CCL26 expression in patients with chronic rhinosinusitis with nasal polyps: Possible role of the nongastric H,K-ATPase. J Allergy Clin Immunol 2016; 139:130-141.e11. [PMID: 27717558 DOI: 10.1016/j.jaci.2016.07.020] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 05/31/2016] [Accepted: 07/14/2016] [Indexed: 12/12/2022]
Abstract
BACKGROUND Chronic rhinosinusitis with nasal polyps (CRSwNP) is often characterized by tissue eosinophilia that is associated with poor prognosis. Recent findings that proton pump inhibitors (PPIs) directly modulate the expression of eotaxin-3, an eosinophil chemoattractant, in patients with eosinophilic diseases suggest therapeutic potential for PPIs in those with CRSwNP. OBJECTIVE We assessed the effect of type 2 mediators, particularly IL-13 and eotaxin-3, on tissue eosinophilia and disease severity in patients with chronic rhinosinusitis (CRS). Further investigation focused on PPI suppression of eotaxin-3 expression in vivo and in vitro, with exploration of underlying mechanisms. METHODS Type 2 mediator levels in nasal tissues and secretions were measured by using a multiplex immunoassay. Eotaxin-3 and other chemokines expressed in IL-13-stimulated human sinonasal epithelial cells (HNECs) and BEAS-2B cells with or without PPIs were assessed by using ELISA, Western blotting, real-time PCR, and intracellular pH imaging. RESULTS Nasal tissues and secretions from patients with CRSwNP had increased IL-13, eotaxin-2, and eotaxin-3 levels, and these were positively correlated with tissue eosinophil cationic protein levels and radiographic scores in patients with CRS (P < .05). IL-13 stimulation of HNECs and BEAS-2B cells dominantly induced eotaxin-3 expression, which was significantly inhibited by PPIs (P < .05). Patients with CRS taking PPIs also showed lower in vivo eotaxin-3 levels compared with those without PPIs (P < .05). Using intracellular pH imaging and altering extracellular K+, we found that IL-13 enhanced H+,K+-exchange, which was blocked by PPIs and the mechanistically unrelated H,K-ATPase inhibitor, SCH-28080. Furthermore, knockdown of ATP12A (gene for the nongastric H,K-ATPase) significantly attenuated IL-13-induced eotaxin-3 expression in HNECs. PPIs also had effects on accelerating IL-13-induced eotaxin-3 mRNA decay. CONCLUSION Our results demonstrated that PPIs reduce IL-13-induced eotaxin-3 expression by airway epithelial cells. Furthermore, mechanistic studies suggest that the nongastric H,K-ATPase is necessary for IL-13-mediated epithelial responses, and its inhibitors, including PPIs, might be of therapeutic value in patients with CRSwNP by reducing epithelial production of eotaxin-3.
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Affiliation(s)
- Jin-Young Min
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | - Christopher J Ocampo
- Division of Allergy-Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | - Whitney W Stevens
- Division of Allergy-Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | - Caroline P E Price
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | - Christopher F Thompson
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | - Tetsuya Homma
- Division of Allergy-Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Ill; Division of Respiratory Medicine and Allergology, Department of Internal Medicine, Showa University School of Medicine, Tokyo, Japan
| | - Julia H Huang
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | - James E Norton
- Division of Allergy-Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | - Lydia A Suh
- Division of Allergy-Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | - Kathryn L Pothoven
- Division of Allergy-Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | - David B Conley
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | - Kevin C Welch
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | | | - Anju T Peters
- Division of Allergy-Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | - Leslie C Grammer
- Division of Allergy-Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | - Kathleen E Harris
- Division of Allergy-Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | - Kathryn E Hulse
- Division of Allergy-Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | - Atsushi Kato
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, Chicago, Ill; Division of Allergy-Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | - Nikolai N Modyanov
- Department of Physiology and Pharmacology, University of Toledo College of Medicine, Toledo, Ohio
| | - Robert C Kern
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, Chicago, Ill; Division of Allergy-Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | - Robert P Schleimer
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, Chicago, Ill; Division of Allergy-Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | - Bruce K Tan
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, Chicago, Ill.
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Görögh T, Bèress L, Quabius ES, Ambrosch P, Hoffmann M. Head and neck cancer cells and xenografts are very sensitive to palytoxin: decrease of c-jun n-terminale kinase-3 expression enhances palytoxin toxicity. Mol Cancer 2013; 12:12. [PMID: 23409748 PMCID: PMC3585753 DOI: 10.1186/1476-4598-12-12] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Accepted: 02/06/2013] [Indexed: 02/01/2023] Open
Abstract
Objectives Palytoxin (PTX), a marine toxin isolated from the Cnidaria (zooanthid) Palythoa caribaeorum is one of the most potent non-protein substances known. It is a very complex molecule that presents both lipophilic and hydrophilic areas. The effect of PTX was investigated in a series of experiments conducted in head and neck squamous cell carcinoma (HNSCC) cell lines and xenografts. Materials and methods Cell viability, and gene expression of the sodium/potassium-transporting ATPase subumit alpha1 (ATP1AL1) and GAPDH were analyzed in HNSCC cells and normal epithelial cells after treatment with PTX using cytotoxicity-, clonogenic-, and enzyme inhibitor assays as well as RT-PCR and Northern Blotting. For xenograft experiments severe combined immunodeficient (SCID) mice were used to analyze tumor regression. The data were statistically analyzed using One-Way Annova (SPSS vs20). Results Significant toxic effects were observed in tumor cells treated with PTX (LD50 of 1.5 to 3.5 ng/ml) in contrast to normal cells. In tumor cells PTX affected both the release of LDH and the expression of the sodium/potassium-transporting ATPase subunit alpha1 gene suggesting loss of cellular integrity, primarily of the plasma membrane. Furthermore, strong repression of the c-Jun N-terminal kinase 3 (JNK3) mRNA expression was found in carcinoma cells which correlated with enhanced toxicity of PTX suggesting an essential role of the mitogen activated protein kinase (MAPK)/JNK signalling cascades pathway in the mechanisms of HNSCC cell resistance to PTX. In mice inoculated with carcinoma cells, injections of PTX into the xenografted tumors resulted within 24 days in extensive tumor destruction in 75% of the treated animals (LD50 of 68 ng/kg to 83 ng/kg) while no tumor regression occurred in control animals. Conclusions These results clearly provide evidence that PTX possesses preferential toxicity for head and neck carcinoma cells and therefore it is worth further studying its impact which may extend our knowledge of the biology of head and neck cancer.
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Affiliation(s)
- Tibor Görögh
- Department of Otorhinolaryngology- Head and Neck Surgery, Section of Experimental Oncology, University of Kiel Schleswig-Holstein, Kiel, 24105, Germany.
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Bchetnia M, Tremblay ML, Leclerc G, Dupérée A, Powell J, McCuaig C, Morin C, Legendre-Guillemin V, Laprise C. Expression signature of epidermolysis bullosa simplex. Hum Genet 2011; 131:393-406. [DOI: 10.1007/s00439-011-1077-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Accepted: 07/29/2011] [Indexed: 01/24/2023]
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Abstract
PURPOSE OF REVIEW We integrate recent evidence that demonstrates the importance of the gastric (HKalpha1) and nongastric (HKalpha2)-containing hydrogen potassium adenosine triphosphatases (H,K-ATPases) on physiological function and their role in potassium (K), sodium (Na), and acid-base balance. RECENT FINDINGS Previous studies focused on the primary role of H,K-ATPases as a mechanism of K conservation during states of K deprivation. Both isoforms function in H secretion and K absorption in vivo during K deprivation, but recent findings show that these pumps also function in acid secretion in animals fed normal K-replete diets. The complicated pharmacological inhibition of both pumps is reviewed. Interestingly, HKalpha2-null mice have a reduced expression and activity of the renal epithelial Na channel alpha subunit in the colon. When the human nongastric isoform was studied in a heterologous expression system with its cognate beta subunit (NaKbeta1), the pump exhibited substantial Na affinity at the 'K'-binding site. Evidence cited herein raises the possibility that either directly or indirectly the renal HKalpha2-containing H,K-ATPase may affect Na balance. SUMMARY Both H,K-ATPase isoforms are active in normal animals and not just under conditions of K depletion. The possibility that either one or both isoforms contribute to Na absorption, particularly in humans, raises important clinical implications for these pumps in the kidney.
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Pestov NB, Korneenko TV, Shakhparonov MI, Shull GE, Modyanov NN. Loss of acidification of anterior prostate fluids in Atp12a-null mutant mice indicates that nongastric H-K-ATPase functions as proton pump in vivo. Am J Physiol Cell Physiol 2006; 291:C366-74. [PMID: 16525125 DOI: 10.1152/ajpcell.00042.2006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The physiological functions of nongastric (colonic) H-K-ATPase (gene symbol Atp12a), unlike those of Na-K-ATPase and gastric H-K-ATPase, are poorly understood. It has been suggested that it pumps Na+ more efficiently than H+; however, so far, there is no direct evidence that it pumps H+ in vivo. Previously, we found that the nongastric H-K-ATPase alpha-subunit is expressed in apical membranes of rodent anterior prostate epithelium, in a complex with the Na-K-ATPase beta1-subunit. Here we report the effects of Atp12a gene ablation on polarization of the beta1-subunit and secretory function of the anterior prostate. In nongastric H-K-ATPase-deficient prostate, the Na-K-ATPase alpha-subunit resided exclusively in basolateral membranes; however, the beta1-subunit disappeared from apical membranes, demonstrating that beta1 is an authentic subunit of nongastric H-K-ATPase in vivo and that apical localization of beta1 in the prostate is completely dependent on its association with the nongastric H-K-ATPase alpha-subunit. A remarkable reduction in acidification of anterior prostate fluids was observed: pH 6.38 +/- 0.14 for wild-type mice and 6.96 +/- 0.10 for homozygous mutants. These results show that nongastric H-K-ATPase is required for acidification of luminal prostate fluids, thereby providing a strong in vivo correlate of previous functional expression studies demonstrating that it operates as a proton pump.
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Affiliation(s)
- Nikolay B Pestov
- Dept. of Physiology, Pharmacology, Metabolism, and Cardiovascular Sciences, Med. Univ. of Ohio, 3035 Arlington Ave., Toledo, OH 43614, USA
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Johansson M, Jansson T, Pestov NB, Powell TL. Non-gastric H+/K+ ATPase is present in the microvillous membrane of the human placental syncytiotrophoblast. Placenta 2004; 25:505-11. [PMID: 15135233 DOI: 10.1016/j.placenta.2003.11.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2003] [Revised: 11/18/2003] [Accepted: 11/19/2003] [Indexed: 11/25/2022]
Abstract
In humans, the non-gastric H(+)/K(+)ATPase (ATP1AL1) has previously been shown to be expressed in the epithelia of skin, kidney and colon. In this study we tested the hypothesis that the non-gastric H(+)/K(+)ATPase is localized to the syncytiotrophoblast, the transporting epithelium of the human placenta. Microvillous (MVM) and basal plasma membranes (BM) of the syncytiotrophoblast were isolated from term placenta and membrane proteins were separated using SDS-PAGE. The ATP1AL1 protein was identified as a 114 kD band in both MVM and BM by Western blot, however, the protein was more abundant in the MVM. Using immunocytochemistry H(+)/K(+)ATPase protein was localized in MVM but not BM. We constructed primers specific for ATP1AL1 and performed RT-PCR on RNA isolated from human placenta and human kidney. A product of the expected size could be detected in both tissues after 30 cycles of amplification. The sequence identity of this 517 nucleotide product was confirmed by sequencing and found to be identical to the human non-gastric H(+)/K(+)ATPase. The activity of this proton pump appears to be low in normal healthy placental at term, however, it is speculated that MVM non-gastric H(+)/K(+)ATPase may be important in pathological states. In conclusion, non-gastric H(+)/K(+)ATPase is present in the microvillous plasma membrane of the transporting epithelia of the human placenta.
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Affiliation(s)
- M Johansson
- Perinatal Center, Department of Physiology and Pharmacology, Göteborg University, Box 432, 40530 Goteborg, Sweden
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12
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Crambert G, Horisberger JD, Modyanov NN, Geering K. Human nongastric H+-K+-ATPase: transport properties of ATP1al1 assembled with different beta-subunits. Am J Physiol Cell Physiol 2002; 283:C305-14. [PMID: 12055100 DOI: 10.1152/ajpcell.00590.2001] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To investigate whether nongastric H+-K+-ATPases transport Na+ in exchange for K+ and whether different beta-isoforms influence their transport properties, we compared the functional properties of the catalytic subunit of human nongastric H+-K+-ATPase, ATP1al1 (AL1), and of the Na+-K+-ATPase alpha1-subunit (alpha1) expressed in Xenopus oocytes, with different beta-subunits. Our results show that betaHK and beta1-NK can produce functional AL1/beta complexes at the oocyte cell surface that, in contrast to alpha1/beta1 NK and alpha1/betaHK complexes, exhibit a similar apparent K+ affinity. Similar to Na+-K+-ATPase, AL1/beta complexes are able to decrease intracellular Na+ concentrations in Na+-loaded oocytes, and their K+ transport depends on intra- and extracellular Na+ concentrations. Finally, controlled trypsinolysis reveals that beta-isoforms influence the protease sensitivity of AL1 and alpha1 and that AL1/beta complexes, similar to the Na+-K+-ATPase, can undergo distinct K+-Na+- and ouabain-dependent conformational changes. These results provide new evidence that the human nongastric H+-K+-ATPase interacts with and transports Na+ in exchange for K+ and that beta-isoforms have a distinct effect on the overall structural integrity of AL1 but influence its transport properties less than those of the Na+-K+-ATPase alpha-subunit.
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Affiliation(s)
- Gilles Crambert
- Institute Of Pharmacology And Toxicology of The University, CH-1005 Lausanne, Switzerland
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13
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Takahashi Y, Sakai H, Kuragari M, Suzuki T, Tauchi K, Minamimura T, Tsukada K, Asano S, Takeguchi N. Expression of ATP1AL1, a non-gastric proton pump, in human colorectum. THE JAPANESE JOURNAL OF PHYSIOLOGY 2002; 52:317-21. [PMID: 12230809 DOI: 10.2170/jjphysiol.52.317] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The expression of mRNAs encoding a human nongastric proton pump (ATP1AL1) in the colorectum was investigated. The real-time PCR gave significant levels of signals not only in the distal part of human colon and rectum, but also in the proximal part of the colon. ATP1AL1 mRNA was overexpressed in 12 out of 20 human colorectal adenocarcinomas compared with the level in the accompanying normal mucosa. It is noted that astonishing levels of the mRNA overexpression were found in 4 carcinomas, which were detected even by Northern blot. The very high levels of ATP1AL1 mRNA expression in some cancer tissues may be connected to an unknown specific pathophysiological condition.
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Affiliation(s)
- Yuji Takahashi
- Department of Pharmaceutical Physiology, Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Toyama, 930-0194 Japan
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14
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Pestov NB, Korneenko TV, Adams G, Tillekeratne M, Shakhparonov MI, Modyanov NN. Nongastric H-K-ATPase in rodent prostate: lobe-specific expression and apical localization. Am J Physiol Cell Physiol 2002; 282:C907-16. [PMID: 11880279 DOI: 10.1152/ajpcell.00258.2001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The molecular basis of active ion transport in secretory glands such as the prostate is not well characterized. Rat nongastric H-K-ATPase is expressed at high levels in distal colon surface cell apical membranes and thus is referred to as "colonic." Here we show that the ATPase is expressed in rodent prostate complex in a lobe-specific manner. RT-PCR and Western blot analyses indicate that rat nongastric H-K-ATPase alpha-subunit (alpha(ng)) mRNA and protein are present in coagulating gland (anterior prostate) and lateral and dorsal prostate and absent from ventral lobe, whereas Na-K-ATPase alpha-subunit is present in all lobes. RT-PCR analysis shows that Na-K-ATPase alpha(4) and alpha(3) and gastric H-K-ATPase alpha-subunit are not present in significant amounts in all prostate lobes. Relatively low levels of Na-K-ATPase alpha(2) were found in lateral, dorsal, and anterior lobes. alpha(ng) protein expression is anteriodorsolateral: highest in coagulating gland, somewhat lower in dorsal lobe, and even lower in lateral lobe. Na-K-ATPase protein abundance has the reverse order: expression in ventral lobe is higher than in coagulating gland. alpha(ng) protein abundance is higher in coagulating gland than distal colon membranes. Immunohistochemistry shows that in rat and mouse coagulating gland epithelium alpha(ng) protein has an apical polarization and Na-K-ATPase alpha(1) is localized in basolateral membranes. The presence of nongastric H-K-ATPase in rodent prostate apical membranes may indicate its involvement in potassium concentration regulation in secretions of these glands.
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Affiliation(s)
- Nikolay B Pestov
- Department of Pharmacology, Medical College of Ohio, 3035 Arlington Ave., Toledo, OH 43614, USA
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15
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Reinhardt J, Grishin AV, Oberleithner H, Caplan MJ. Differential localization of human nongastric H(+)-K(+)-ATPase ATP1AL1 in polarized renal epithelial cells. Am J Physiol Renal Physiol 2000; 279:F417-25. [PMID: 10966921 DOI: 10.1152/ajprenal.2000.279.3.f417] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The human H(+)-K(+)-ATPase, ATP1AL1, belongs to the subgroup of nongastric, K(+)-transporting ATPases. In concert with the structurally related gastric H(+)-K(+)-ATPase, it plays a major role in K(+) reabsorption in various tissues, including colon and kidney. Physiological and immunocytochemical data suggest that the functional heteromeric ion pumps are usually found in the apical plasma membranes of renal epithelial cells. However, the low expression levels of characteristic nongastric ion pumps makes it difficult to verify their spatial distribution in vivo. To investigate the sorting behavior of ATP1AL1, we expressed this pump by stable transfection in MDCK and LLC-PK(1) renal epithelial cell lines. Stable interaction of ATP1AL1 with either the endogenous Na(+)-K(+)-ATPase beta-subunit or the gastric H(+)-K(+)-ATPase beta-subunit was tested by confocal immunofluorescence microscopy and surface biotinylation. In cells transfected with ATP1AL1 alone, the alpha-subunit accumulated intracellularly, consistent with its inability to assemble and travel to the plasma membrane with the endogenous Na(+)-K(+)-ATPase beta-subunit. Cotransfection of ATP1AL1 with the gastric H(+)-K(+)-ATPase beta-subunit resulted in plasma membrane localization of both pump subunits. In cotransfected MDCK cells the heteromeric ion pump was predominantly polarized to the apical plasma membrane. Functional expression of ATP1AL1 was confirmed by (86)Rb(+) uptake measurements. In contrast, cotransfected LLC-PK(1) cells accumulate ATP1AL1 at the lateral membrane. The distinct polarization of ATP1AL1 indicates that the alpha-subunit encodes sorting information that is differently interpreted by cell type-specific sorting mechanisms.
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Affiliation(s)
- J Reinhardt
- Department of Physiology, University of Münster, 48149 Münster, Germany
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16
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Pestov NB, Adams G, Shakhparonov MI, Modyanov NN. Identification of a novel gene of the X,K-ATPase beta-subunit family that is predominantly expressed in skeletal and heart muscles. FEBS Lett 1999; 456:243-8. [PMID: 10456317 DOI: 10.1016/s0014-5793(99)00954-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have identified the fifth member of the mammalian X,K-ATPase beta-subunit gene family. The human and rat genes are largely expressed in skeletal muscle and at a lower level in heart. The deduced human and rat proteins designated as beta(muscle) (beta(m)) consist of 357 and 356 amino acid residues, respectively, and exhibit 89% identity. The sequence homology of beta(m) proteins with known Na,K- and H,K-ATPase beta-subunits are 30.5-39.4%. Unlike other beta-subunits, putative beta(m) proteins have large N-terminal cytoplasmic domains containing long Glu-rich sequences. The data obtained indicate the existence of hitherto unknown X,K-ATPase (most probably Na,K-ATPase) isozymes in muscle cells.
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Affiliation(s)
- N B Pestov
- Department of Pharmacology, Medical College of Ohio, Toledo 43614, USA
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17
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Campbell WG, Weiner ID, Wingo CS, Cain BD. H-K-ATPase in the RCCT-28A rabbit cortical collecting duct cell line. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:F237-45. [PMID: 9950954 DOI: 10.1152/ajprenal.1999.276.2.f237] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the present study, we demonstrate that the rabbit cortical collecting duct cell line RCCT-28A possesses three distinct H-K-ATPase catalytic subunits (HKalpha). Intracellular measurements of RCCT-28A cells using the pH-sensitive dye 2', 7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF) indicated that the mechanism accounting for recovery from an acid load exhibited both K+ dependence and sensitivity to Sch-28080 characteristic of H-K-ATPases. Recovery rates were 0.022 +/- 0.005 pH units/min in the presence of K+, 0.004 +/- 0.002 in the absence of K+, and 0.002 +/- 0.002 in the presence of Sch-28080. The mRNAs encoding the HKalpha1 subunit and the H-K-ATPase beta-subunit (HKbeta) were detected by RT-PCR. In addition, two HKalpha2 species were found by RT-PCR and 5' rapid amplification of cDNA ends (5'-RACE) in the rabbit renal cortex. One was homologous to HKalpha2 cDNAs generated from other species, and the second was novel. The latter, referred to as HKalpha2c, encoded an apparent 61-residue amino-terminal extension that bore no homology to reported sequences. Antipeptide antibodies were designed on the basis of this extension, and these antibodies recognized a protein of the appropriate mass in both rabbit renal tissue samples and RCCT-28A cells. Such findings constitute very strong evidence for expression of the HKalpha2c subunit in vivo. The results suggest that the rabbit kidney and RCCT-28A cells express at least three distinct H-K-ATPases.
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Affiliation(s)
- W G Campbell
- Department of Biochemistry and Molecular Biology, and Division of Nephrology, Hypertension, and Transplantation, University of Florida College of Medicine, Gainesville, FL 32610, USA
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18
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Pestov NB, Romanova LG, Korneenko TV, Egorov MV, Kostina MB, Sverdlov VE, Askari A, Shakhparonov MI, Modyanov NN. Ouabain-sensitive H,K-ATPase: tissue-specific expression of the mammalian genes encoding the catalytic alpha subunit. FEBS Lett 1998; 440:320-4. [PMID: 9872395 DOI: 10.1016/s0014-5793(98)01483-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Human ATP1AL1 and corresponding genes of other mammals encode the catalytic alpha subunit of a non-gastric ouabain-sensitive H,K-ATPases, the ion pump presumably involved in maintenance of potassium homeostasis. The tissue specificity of the expression of these genes in different species has not been analyzed in detail. Here we report comparative RT-PCR screening of mouse, rat, rabbit, human, and dog tissues. Significant expression levels were observed in the skin, kidney and distal colon of all species (with the exception of the human colon). Analysis of rat urogenital organs also revealed strong expression in coagulating and preputial glands. Relatively lower expression levels were detected in many other tissues including brain, placenta and lung. In rabbit brain the expression was found to be specific to choroid plexus and cortex. Prominent similarity of tissue-specific expression patterns indicates that animal and human non-gastric H,K-ATPases are indeed products of homologous genes. This is also consistent with the high sequence similarity of non-gastric H,K-ATPases (including partial sequences of hitherto unknown cDNAs for mouse and dog proteins).
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Affiliation(s)
- N B Pestov
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow
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19
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Wang T, Courtois-Coutry N, Giebisch G, Caplan MJ. A tyrosine-based signal regulates H-K-ATPase-mediated potassium reabsorption in the kidney. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 275:F818-26. [PMID: 9815140 DOI: 10.1152/ajprenal.1998.275.5.f818] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Isoforms of the H-K-ATPase participate in active K resorption in the renal collecting tubule. The cytoplasmic tail of the beta-subunit of the gastric H-K-ATPase includes a 4 amino acid motif which is highly homologous to tyrosine-based endocytosis signals. We have generated transgenic mice expressing an H-K-ATPase beta-subunit in which the tyrosine residue in this sequence has been mutated to alanine. Mice expressing the mutated protein manifest constitutive hypersecretion of gastric acid, demonstrating that the beta-subunit tyrosine-based motif is required for the regulated endocytosis of the H-K pump and hence the cessation of gastric acid output. To test the possibility that the tyrosine-based sequence in the tail of the H-K-ATPase beta-subunit plays a role in regulating the function of renal H-K-ATPases, we examined renal K clearance in normal and in transgenic mice. Blood pressure, urine volume, glomerular filtration rate (GFR), plasma Na, and Na excretion are similar in control and transgenic mice. However, plasma K concentrations are significantly higher in transgenic mice (4.76 +/- 0.13 meq/l in transgenic and 4. 12 +/- 0.04 meq/l in control; n = 9, P < 0.05) and K excretion is lower in the transgenic animals (fractional excretion of K was 26.2 +/- 3.62% in transgenic and 50.1 +/- 4.78% in control; n = 9, P < 0. 01). These data suggest that the tyrosine-based signal in the cytoplasmic tail of the H-K-ATPase beta-subunit functions in the kidney as it does in the stomach to internalize H-K pump and thus inactivate pump function. Its elimination may result in the constitutive presence of the pump at the cell surface and lead to excessive urinary K reabsorption.
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Affiliation(s)
- T Wang
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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20
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Shirihai O, Smith P, Hammar K, Dagan D. Microglia generate external proton and potassium ion gradients utilizing a member of the H/K ATPase family. Glia 1998. [DOI: 10.1002/(sici)1098-1136(199808)23:4<339::aid-glia6>3.0.co;2-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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21
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Abstract
The H+/K(+)-ATPase of gastric parietal cells catalyzes acid secretion in the stomach. Regulation of this pump's function involves its targeting to an intracellular storage compartment, which fuses with the apical plasma membrane in response to secretagogue stimulation. The H+/K(+)-ATPase must also be returned to this intracellular storage compartment to inactivate acid secretion. Recent research suggests that a number of targeting signals and protein-protein interactions participate in governing this process.
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Affiliation(s)
- M J Caplan
- Department of Cellular and Molecular Physiology, Yale University School of Medicine. New Haven, CT 06525, USA.
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22
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Bookstein C, Xie Y, Rabenau K, Musch MW, McSwine RL, Rao MC, Chang EB. Tissue distribution of Na+/H+ exchanger isoforms NHE2 and NHE4 in rat intestine and kidney. THE AMERICAN JOURNAL OF PHYSIOLOGY 1997; 273:C1496-505. [PMID: 9374634 DOI: 10.1152/ajpcell.1997.273.5.c1496] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We present evidence that tissue distribution of two highly conserved Na+/H+ exchanger isoforms, NHE2 and NHE4, differs significantly from previously published reports. Riboprobes unique to each of these antiporters, from 5' (noncoding and coding) and 3' coding regions, were used to analyze mRNA from adult rat kidney and intestine by ribonuclease protection assay and in situ hybridization. In contrast to earlier work that concluded that both NHE2 and NHE4 were expressed throughout the intestine and in the kidney, our data show that there is no NHE2 message in the kidney and NHE4 is not expressed in small or large intestine. Analyses of intestinal epithelial and kidney membrane proteins by an NHE2-specific antibody identified a doublet at < 90 kDa in intestine but not in kidney. NHE2 is highly expressed in the Na(+)-absorptive epithelium of jejunum, ileum, and ascending and descending colon. NHE4 mRNA message is found in the inner medulla of the kidney as previously reported (C. Bookstein, M. W. Musch, A. DePaoli, Y. Xie, M. Villereal, M. C. Rao, and E. B. Chang. J. Biol. Chem. 269: 29704-29709, 1994) and not in the intestine. From these data, we speculate that neither NHE2 nor NHE4 has a role in renal Na+ absorption. NHE2 is likely involved in gut Na+ absorption, whereas NHE4 may have a specialized role in cell volume rectification of inner medullary collecting duct cells. Knowledge of the correct tissue and cell-specific distribution of these two antiporters should help significantly in understanding their physiological roles.
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Affiliation(s)
- C Bookstein
- Department of Medicine, University of Chicago, Illinois 60637, USA
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23
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Marsy S, Elalouf JM, Doucet A. Quantitative RT-PCR analysis of mRNAs encoding a colonic putative H, K-ATPase alpha subunit along the rat nephron: effect of K+ depletion. Pflugers Arch 1996; 432:494-500. [PMID: 8766009 DOI: 10.1007/s004240050161] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The rat nephron displays two ouabain-sensitive K-ATPases: one, which is present in proximal tubules and thick ascending limbs of normal rats, is specifically activated by K+ and is down-regulated by K+ depletion, whereas the other one appears in collecting ducts of K+-depleted rats and is activated by either Na+ or K+. To determine which of these two ATPases is similar to colonic-type H,K-ATPase, we quantitated by reverse transcriptase-polymerase chain reaction (RT-PCR) the mRNAs encoding the colonic H,K-ATPase alpha subunit in microdissected nephron segments. In normal rats, statistically significant amounts of colonic H,K-ATPase mRNAs were detected exclusively in cortical thick ascending limbs and cortical collecting ducts (200-500 copies/mm). Because these levels of expression were low (1-1.2 copies/target cell), they probably have no physiological relevance. In rats fed a K+-depleted diet for 2 weeks, expression of colonic H,K-ATPase was markedly enhanced in cortical and medullary collecting ducts (5000-12,000 copies/mm or 30-40 copies per cell), whereas it remained low in all other nephron segments. Thus, colonic H,K-ATPase alpha subunit is specifically expressed in cortical and outer medullary collecting ducts of K+-depleted rats where it likely accounts for the ouabain-sensitive K-ATPase activity.
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Affiliation(s)
- S Marsy
- Laboratoire de Biologie Intégrée des Cellules Rénales, Service de Biologie Cellulaire, CEA Saclay, Unité 1859 associée au CNRS, France
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Abstract
1. H+/K(+)-ATPases are members of the P-type ATPase multigene family. The prototypical H+/K(+)-ATPase is the protein that acidifies gastric luminal contents. The physiological and pharmacological significance of this pump has led to a detailed investigation of its biochemistry and molecular and cell biology. 2. Recently, a number of closely related H+/K(+)-ATPase isoforms have been discovered. These isoforms are present in organs other than the stomach, including the colon and kidney, where they contribute to acid-base and potassium homeostasis. The structure, expression and physiological roles of the gastric H+/K(+)-ATPase and other isoforms are reviewed.
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Affiliation(s)
- I R van Driel
- Department of Pathology and Immunology, Monash University Medical School, Melbourne, Victoria, Australia
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25
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Shamraj OI, Lingrel JB. A putative fourth Na+,K(+)-ATPase alpha-subunit gene is expressed in testis. Proc Natl Acad Sci U S A 1994; 91:12952-6. [PMID: 7809153 PMCID: PMC45558 DOI: 10.1073/pnas.91.26.12952] [Citation(s) in RCA: 173] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The Na+,K(+)-ATPase alpha subunit has three known isoforms, alpha 1, alpha 2 and alpha 3, each encoded by a separate gene. This study was undertaken to determine the functional status of a fourth human alpha-like gene, ATP1AL2. Partial genomic sequence analysis revealed regions exhibiting sequence similarity with exons 3-6 of the Na+,K(+)-ATPase alpha isoform genes. ATP1AL2 cDNAs spanning the coding sequence of a novel P-type ATPase alpha subunit were isolated from a rat testis library. The predicted polypeptide is 1028 amino acids long and exhibits 76-78% identity with the rat Na+,K(+)-ATPase alpha 1, alpha 2 and alpha 3 isoforms, indicating that ATP1AL2 may encode a fourth Na+,K(+)-ATPase alpha isoform. A 3.9-kb mRNA is expressed abundantly in human and rat testis.
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Affiliation(s)
- O I Shamraj
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, OH 45267-0524
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26
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Grishin AV, Sverdlov VE, Kostina MB, Modyanov NN. Cloning and characterization of the entire cDNA encoded by ATP1AL1--a member of the human Na,K/H,K-ATPase gene family. FEBS Lett 1994; 349:144-50. [PMID: 8045293 DOI: 10.1016/0014-5793(94)00655-5] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The cDNA for ATP1AL1--the fifth member of the human Na,K-/H,K-ATPase gene family--was cloned and sequenced. The deduced primary ATP1AL1 translation product is 1,039 amino acids in length and has Mr of 114,543. The encoded protein has all of the structural features common to known catalytic subunits of P-type membrane ion-transporting ATPases and is equally distant (63-64% of identity) from the Na,K-ATPase isoforms and the gastric H,K-ATPase. The ATP1AL1 encoded protein was proposed to represent a new separate group within the family of human potassium-dependent ion pumps.
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Affiliation(s)
- A V Grishin
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow
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27
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Jaisser F, Horisberger JD, Geering K, Rossier BC. Mechanisms of urinary K+ and H+ excretion: primary structure and functional expression of a novel H,K-ATPase. J Cell Biol 1993; 123:1421-9. [PMID: 8253841 PMCID: PMC2290882 DOI: 10.1083/jcb.123.6.1421] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The kidney plays an essential role in regulating potassium and acid balance. A major site for these regulations is in the collecting tubule. In the present study, we report the primary sequence of a novel alpha subunit of the P-ATPase gene family, which we isolated from the urinary bladder epithelium of the toad Bufo marinus, the amphibian equivalent of the mammalian collecting tubule. The cDNA encodes a protein of 1,042 amino acids which shares approximately 67% identity with the alpha 1 subunit of the ouabain-inhibitable Na,K-ATPase and approximately 69% identity with the alpha subunit of the SCH28080-inhibitable gastric H,K-ATPase. When coexpressed in Xenopus oocytes with a beta subunit isolated from the same cDNA library, the ATPase is able to transport rubidium (a potassium surrogate) inward, and hydrogen outward, leading to alkalization of the intracellular compartment and acidification of the external medium. The novel ATPase has a unique pharmacological profile showing intermediate sensitivity to both ouabain and SCH28080. Our findings indicate that the bladder ATPase is a member of a new ion motive P-ATPase subfamily. The bladder ATPase is expressed in the urinary tract but not in the stomach or the colon. This H,K-ATPase may be one of the molecules involved in H+ and K+ homeostasis, mediating the transport of these ions across urinary epithelia and therefore regulating their urinary excretion.
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Affiliation(s)
- F Jaisser
- Institut de Pharmacologie et de Toxicologie de l'Université, Lausanne, Switzerland
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28
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Middleton J, Khan W, Collinsworth G, Hannun Y, Medford R. Heterogeneity of protein kinase C-mediated rapid regulation of Na/K-ATPase in kidney epithelial cells. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)82345-6] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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29
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Abstract
The review is devoted to analysis of research carried out in the author's laboratory on structure-function relationships in genes coding for Na,K-ATPases. Also considered are problems related to molecular evolution of ion-transporting ATPases. This brief review is devoted to a fragment of research carried out in my laboratory, the Laboratory of Human Genes Structure and Function at the Shemyakin Institute of Bioorganic Chemistry, USSR Academy of Sciences. The area of the review may be named as structural-evolutionary analysis of functional anatomies of genes. The approach is fairly standard and its essence was formulated long ago: evolution decides 'to be or not to be' based on usefulness or lack of it. The elements of genes that are important for the gene function are retained in the course of evolution, and a comparison of genes having similar functions in different species should, hopefully, reveal different behavior of gene blocks, conservation of functionally significant blocks and variability of less significant or insignificant ones. An approach like this has been widely used in comparing proteins. However, a study of genes gives the investigator yet another tool of structural and evolutionary import: the exon structure may be relevant to the gene's evolutionary history, with exons corresponding to the functional domains (arguments for and against this fascinating hypothesis have been reviewed by Blake (Blake, 1985). However, even if the exon-domain correlation does not hold in the general case, a similarity in the exon-intron pattern of genes from different species is indicative of their common evolutionary origin and is enforcing the logic of variability analysis, provided, of course, that the compared genes have a common predecessor. A few years ago we employed this approach to analyze the functional structure of genes coding for subunits of bacterial DNA-dependent RNA polymerases and constructed functional maps of the enzyme. After that, a similar study of Na,K-ATPase genes to be reviewed here was started. The entire project became possible through collaboration with the lab of Dr. N. N. Modyanov, an eminent specialist in protein chemistry who had already accumulated considerable information on Na,K-ATPase from pig kidneys by that time. I would also like to stress that the work has been started on the initiative of the deceased Director of the Institute, Yu. A. Ovchinnikov. Since this is a self-review, I am asking my colleagues whose work will not be cited here to excuse me.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- E D Sverdlov
- Institute of Molecular Genetics, USSR Academy of Sciences, Moscow
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