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Mungara P, Waiss M, Hartwig S, Burger D, Cordat E. Unraveling the molecular landscape of kAE1: a narrative review. Can J Physiol Pharmacol 2024; 102:396-407. [PMID: 38669699 DOI: 10.1139/cjpp-2023-0482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2024]
Abstract
Kidney anion exchanger 1 (kAE1) is an isoform of the AE1 protein encoded by the SLC4A1 gene. It is a basolateral membrane protein expressed by α-intercalated cells in the connecting tubules and collecting duct of the kidney. Its main function is to exchange bicarbonate and chloride ions between the blood and urine to maintain blood pH at physiological threshold. The kAE1 protein undergoes multiple post-translational modifications such as phosphorylation and ubiquitination and interacts with many different proteins such as claudin-4 and carbonic anhydrase II. Mutations in the gene may lead to the development of distal renal tubular acidosis, characterized by the failure to acidify the urine, which may result in nephrocalcinosis and in more severe cases, renal failure. In this review, we discuss the structure and function of kAE1, its post-translational modifications, and protein-protein interactions. Finally, we discuss insights gained from the study of kAE1 mutations in humans and in mice.
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Affiliation(s)
- Priyanka Mungara
- Department of Physiology, Membrane Protein Disease Research Group, Faculty of Medicine, College of Health Sciences, University of Alberta, Edmonton, AB, Canada
| | - Moubarak Waiss
- School of Pharmaceutical Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Sunny Hartwig
- Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, Canada
| | - Dylan Burger
- School of Pharmaceutical Sciences, University of Ottawa, Ottawa, ON, Canada
- Ottawa Hospital Research Institute, Kidney Research Centre, Ottawa, ON, Canada
| | - Emmanuelle Cordat
- Department of Physiology, Membrane Protein Disease Research Group, Faculty of Medicine, College of Health Sciences, University of Alberta, Edmonton, AB, Canada
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2
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Chávez JC, Carrasquel-Martínez G, Hernández-Garduño S, Matamoros Volante A, Treviño CL, Nishigaki T, Darszon A. Cytosolic and Acrosomal pH Regulation in Mammalian Sperm. Cells 2024; 13:865. [PMID: 38786087 PMCID: PMC11120249 DOI: 10.3390/cells13100865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 05/07/2024] [Accepted: 05/09/2024] [Indexed: 05/25/2024] Open
Abstract
As in most cells, intracellular pH regulation is fundamental for sperm physiology. Key sperm functions like swimming, maturation, and a unique exocytotic process, the acrosome reaction, necessary for gamete fusion, are deeply influenced by pH. Sperm pH regulation, both intracellularly and within organelles such as the acrosome, requires a coordinated interplay of various transporters and channels, ensuring that this cell is primed for fertilization. Consistent with the pivotal importance of pH regulation in mammalian sperm physiology, several of its unique transporters are dependent on cytosolic pH. Examples include the Ca2+ channel CatSper and the K+ channel Slo3. The absence of these channels leads to male infertility. This review outlines the main transport elements involved in pH regulation, including cytosolic and acrosomal pH, that participate in these complex functions. We present a glimpse of how these transporters are regulated and how distinct sets of them are orchestrated to allow sperm to fertilize the egg. Much research is needed to begin to envision the complete set of players and the choreography of how cytosolic and organellar pH are regulated in each sperm function.
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Affiliation(s)
- Julio C. Chávez
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología (IBT), Universidad Nacional Autónoma de México (UNAM), Cuernavaca 62210, Morelos, Mexico; (J.C.C.); (G.C.-M.)
| | - Gabriela Carrasquel-Martínez
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología (IBT), Universidad Nacional Autónoma de México (UNAM), Cuernavaca 62210, Morelos, Mexico; (J.C.C.); (G.C.-M.)
- CITMER, Medicina Reproductiva, México City 11520, Mexico
| | - Sandra Hernández-Garduño
- Departamento de Morfología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México (UNAM), México City 04510, Mexico;
| | - Arturo Matamoros Volante
- Department of Electrical and Computer Engineering and School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA;
| | - Claudia L. Treviño
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología (IBT), Universidad Nacional Autónoma de México (UNAM), Cuernavaca 62210, Morelos, Mexico; (J.C.C.); (G.C.-M.)
| | - Takuya Nishigaki
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología (IBT), Universidad Nacional Autónoma de México (UNAM), Cuernavaca 62210, Morelos, Mexico; (J.C.C.); (G.C.-M.)
| | - Alberto Darszon
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología (IBT), Universidad Nacional Autónoma de México (UNAM), Cuernavaca 62210, Morelos, Mexico; (J.C.C.); (G.C.-M.)
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3
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Bourgeois S, Houillier P. State of knowledge on ammonia handling by the kidney. Pflugers Arch 2024; 476:517-531. [PMID: 38448728 PMCID: PMC11006756 DOI: 10.1007/s00424-024-02940-1] [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: 12/21/2023] [Revised: 02/28/2024] [Accepted: 03/01/2024] [Indexed: 03/08/2024]
Abstract
The disposal of ammonia, the main proton buffer in the urine, is important for acid-base homeostasis. Renal ammonia excretion is the predominant contributor to renal net acid excretion, both under basal condition and in response to acidosis. New insights into the mechanisms of renal ammonia production and transport have been gained in the past decades. Ammonia is the only urinary solute known to be produced in the kidney and selectively transported through the different parts of the nephron. Both molecular forms of total ammonia, NH3 and NH4+, are transported by specific proteins. Proximal tubular ammoniagenesis and the activity of these transport processes determine the eventual fate of total ammonia produced and excreted by the kidney. In this review, we summarized the state of the art of ammonia handling by the kidney and highlighted the newest processes described in the last decade.
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Affiliation(s)
- Soline Bourgeois
- Institut of Physiology, University of Zurich, Zurich, Switzerland.
| | - Pascal Houillier
- Centre de Recherche Des Cordeliers, INSERM, Sorbonne Université, Université Paris Cité, Paris, France
- Centre National de La Recherche Scientifique (CNRS), EMR 8228, Paris, France
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4
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Stock C. pH-regulated single cell migration. Pflugers Arch 2024; 476:639-658. [PMID: 38214759 PMCID: PMC11006768 DOI: 10.1007/s00424-024-02907-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 12/21/2023] [Accepted: 01/02/2024] [Indexed: 01/13/2024]
Abstract
Over the last two decades, extra- and intracellular pH have emerged as fundamental regulators of cell motility. Fundamental physiological and pathological processes relying on appropriate cell migration, such as embryonic development, wound healing, and a proper immune defense on the one hand, and autoimmune diseases, metastatic cancer, and the progression of certain parasitic diseases on the other, depend on surrounding pH. In addition, migrating single cells create their own localized pH nanodomains at their surface and in the cytosol. By this means, the migrating cells locally modulate their adhesion to, and the re-arrangement and digestion of, the extracellular matrix. At the same time, the cytosolic nanodomains tune cytoskeletal dynamics along the direction of movement resulting in concerted lamellipodia protrusion and rear end retraction. Extracellular pH gradients as found in wounds, inflamed tissues, or the periphery of tumors stimulate directed cell migration, and long-term exposure to acidic conditions can engender a more migratory and invasive phenotype persisting for hours up to several generations of cells after they have left the acidic milieu. In the present review, the different variants of pH-dependent single cell migration are described. The underlying pH-dependent molecular mechanisms such as conformational changes of adhesion molecules, matrix protease activity, actin (de-)polymerization, and signaling events are explained, and molecular pH sensors stimulated by H+ signaling are presented.
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Affiliation(s)
- Christian Stock
- Department of Gastroenterology, Hepatology, Infectiology & Endocrinology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
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5
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Liao S, Wu G, Xie Z, Lei X, Yang X, Huang S, Deng X, Wang Z, Tang G. pH regulators and their inhibitors in tumor microenvironment. Eur J Med Chem 2024; 267:116170. [PMID: 38308950 DOI: 10.1016/j.ejmech.2024.116170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 01/14/2024] [Accepted: 01/22/2024] [Indexed: 02/05/2024]
Abstract
As an important characteristic of tumor, acidic tumor microenvironment (TME) is closely related to immune escape, invasion, migration and drug resistance of tumor. The acidity of the TME mainly comes from the acidic products produced by the high level of tumor metabolism, such as lactic acid and carbon dioxide. pH regulators such as monocarboxylate transporters (MCTs), carbonic anhydrase IX (CA IX), and Na+/H+ exchange 1 (NHE1) expel protons directly or indirectly from the tumor to maintain the pH balance of tumor cells and create an acidic TME. We review the functions of several pH regulators involved in the construction of acidic TME, the structure and structure-activity relationship of pH regulator inhibitors, and provide strategies for the development of small-molecule antitumor inhibitors based on these targets.
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Affiliation(s)
- Senyi Liao
- Institute of Pharmacy and Pharmacology, Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, China
| | - Guang Wu
- The Second Affiliated Hospital, Department of Pharmacy, Hengyang Medical School, University of South China, Hengyang, 421001, Hunan, China
| | - Zhizhong Xie
- Institute of Pharmacy and Pharmacology, Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, China
| | - Xiaoyong Lei
- Institute of Pharmacy and Pharmacology, Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, China
| | - Xiaoyan Yang
- Institute of Pharmacy and Pharmacology, Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, China
| | - Sheng Huang
- Jiuzhitang Co., Ltd, Changsha, Hunan, 410007, China
| | - Xiangping Deng
- The First Affiliated Hospital, Department of Pharmacy, Hengyang Medical School, University of South China, Hengyang, 421001, Hunan, China.
| | - Zhe Wang
- The Second Affiliated Hospital, Department of Pharmacy, Hengyang Medical School, University of South China, Hengyang, 421001, Hunan, China.
| | - Guotao Tang
- Institute of Pharmacy and Pharmacology, Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, China.
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6
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Chen PL, Huang KT, Chen LY, Hsu K. Erythroid anion Exchanger-1 (band 3) transports nitrite for nitric oxide metabolism. Free Radic Biol Med 2024; 210:237-245. [PMID: 38042224 DOI: 10.1016/j.freeradbiomed.2023.11.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 11/23/2023] [Accepted: 11/26/2023] [Indexed: 12/04/2023]
Abstract
Nitrite (NO2-) interacts with hemoglobin (Hb) in various ways to regulate blood flow. During hypoxic vasodilation, nitrite is reduced by deoxyHb to yield nitric oxide (NO). While NO, a hydrophobic gas, could freely diffuse across the cell membrane, how the reactant nitrite anion could permeate through the red blood cell (RBC) membrane remains unclear. We hypothesized that Cl-/HCO3- anion exchanger-1 (AE1; band 3) abundantly embedded in the RBC membrane could transport NO2-, as HCO3- and NO2- exhibit similar hydrated radii. Here, we monitored NO/N2O3 generated from NO2- inside human RBCs by DAF-FM fluorophore. NO2-, not NO3-, increased intraerythrocytic DAF-FM fluorescence. To test the involvement of AE1-mediated transport in intraerythrocytic NO/N2O3 production from nitrite, we lowered Cl- or HCO3- in the RBC-incubating buffer by 20 % and indeed observed slower rise of the DAF-FM fluorescence. Anti-extracellular AE1, but not anti-intracellular AE1 antibodies, reduced the rates of NO formation from nitrite. The AE1 blocker DIDS similarly reduced the rates of NO/N2O3 production from nitrite in a dose-dependent fashion, confirming that nitrite entered RBCs through AE1. Nitrite inside the RBCs reacted with both deoxyHb and oxyHb, as evidenced by 6.1 % decrease in deoxyHb, 14.7 % decrease in oxyHb, and 20.7 % increase in methemoglobin (metHb). Lowering Cl- in the milieu equally delayed metHb production from nitrite-oxyHb and nitrite-deoxyHb reactions. Thus, AE1-mediated NO2- transport facilitates NO2--Hb reactions inside the red cells, supporting NOx metabolism in circulation.
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Affiliation(s)
- Pin-Lung Chen
- The Laboratory of Immunogenetics, Department of Medical Research, MacKay Memorial Hospital, Tamsui, New Taipei City, Taiwan
| | - Kuang-Tse Huang
- Department of Chemical Engineering, National Chung-Cheng University, Chia-Yi, Taiwan
| | - Li-Yang Chen
- The Laboratory of Immunogenetics, Department of Medical Research, MacKay Memorial Hospital, Tamsui, New Taipei City, Taiwan
| | - Kate Hsu
- The Laboratory of Immunogenetics, Department of Medical Research, MacKay Memorial Hospital, Tamsui, New Taipei City, Taiwan; MacKay Junior College of Medicine, Nursing, and Management, New Taipei City, Taiwan; Institute of Biomedical Sciences, MacKay Medical College, New Taipei City, Taiwan.
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7
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Abstract
Cancers undergo sequential changes to proton (H+) concentration and sensing that are consequences of the disease and facilitate its further progression. The impact of protonation state on protein activity can arise from alterations to amino acids or their titration. Indeed, many cancer-initiating mutations influence pH balance, regulation or sensing in a manner that enables growth and invasion outside normal constraints as part of oncogenic transformation. These cancer-supporting effects become more prominent when tumours develop an acidic microenvironment owing to metabolic reprogramming and disordered perfusion. The ensuing intracellular and extracellular pH disturbances affect multiple aspects of tumour biology, ranging from proliferation to immune surveillance, and can even facilitate further mutagenesis. As a selection pressure, extracellular acidosis accelerates disease progression by favouring acid-resistant cancer cells, which are typically associated with aggressive phenotypes. Although acid-base disturbances in tumours often occur alongside hypoxia and lactate accumulation, there is now ample evidence for a distinct role of H+-operated responses in key events underpinning cancer. The breadth of these actions presents therapeutic opportunities to change the trajectory of disease.
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Affiliation(s)
- Pawel Swietach
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.
| | - Ebbe Boedtkjer
- Department of Biomedicine, Aarhus University, Aarhus, Denmark.
| | - Stine Falsig Pedersen
- Department of Biology, University of Copenhagen, University of Copenhagen, Faculty of Science, København, Denmark.
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8
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Angeli A, Micheli L, Turnaturi R, Pasquinucci L, Parenti C, Alterio V, Di Fiore A, De Simone G, Monti SM, Carta F, Di Cesare Mannelli L, Ghelardini C, Supuran CT. Discovery of a novel series of potent carbonic anhydrase inhibitors with selective affinity for μ Opioid receptor for Safer and long-lasting analgesia. Eur J Med Chem 2023; 260:115783. [PMID: 37678143 DOI: 10.1016/j.ejmech.2023.115783] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 08/29/2023] [Accepted: 08/30/2023] [Indexed: 09/09/2023]
Abstract
In this study, we investigated the development of dual-targeted ligands that bind to both μ-opioid receptor (MOR) and carbonic anhydrase (CA) enzymes, using fentanyl structure as a template. We synthesized and evaluated 21 novel compounds with dual-targeted affinity identifying the lead candidate compound 8, showing selective affinity for MOR and potent inhibition of several cytosolic CA isoforms. By means of repeated treatment of 3 daily administrations for 17 days, fentanyl (0.1 mg/kg, subcutaneously) led to tolerance development, pain threshold alterations and withdrawal symptoms in CD-1 mice, as well as astrocyte and microglia activation in the dorsal horn of the lumbar spinal cord. In contrast, compound 8 (0.32 mg/kg s.c.) maintained stable during days its analgesic effect at the higher dose tested with fewer withdrawal symptoms, allodynia development and glial cells activation. Our results suggest that targeting both MOR and CA enzymes can lead to the development of new class of potent analgesic agents with fewer side effects and reduced tolerance development. Further studies are needed to explore the potential mechanisms underlying these effects and to further optimize the therapeutic potential of these compounds.
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Affiliation(s)
- Andrea Angeli
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche, University of Florence, Via Ugo Schiff 6, 50019, Sesto Fiorentino, Florence, Italy.
| | - Laura Micheli
- Pharmacology and Toxicology Section, Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale G. Pieraccini, 50139, Florence, Italy
| | - Rita Turnaturi
- Department of Drug Sciences and Health, Medicinal Chemistry Section, Università degli Studi di Catania, Viale A. Doria, 6, 95125, Catania, Italy
| | - Lorella Pasquinucci
- Department of Drug Sciences and Health, Medicinal Chemistry Section, Università degli Studi di Catania, Viale A. Doria, 6, 95125, Catania, Italy
| | - Carmela Parenti
- Department of Drug Sciences and Health, Pharmacology and Toxicology Section, Università degli Studi di Catania, Viale A. Doria, 6, 95125, Catania, Italy
| | - Vincenzo Alterio
- Istituto di Biostrutture e Bioimmagini-CNR, via Pietro Castellino, 111, 80131, Naples, Italy
| | - Anna Di Fiore
- Istituto di Biostrutture e Bioimmagini-CNR, via Pietro Castellino, 111, 80131, Naples, Italy
| | - Giuseppina De Simone
- Istituto di Biostrutture e Bioimmagini-CNR, via Pietro Castellino, 111, 80131, Naples, Italy
| | - Simona Maria Monti
- Istituto di Biostrutture e Bioimmagini-CNR, via Pietro Castellino, 111, 80131, Naples, Italy
| | - Fabrizio Carta
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche, University of Florence, Via Ugo Schiff 6, 50019, Sesto Fiorentino, Florence, Italy
| | - Lorenzo Di Cesare Mannelli
- Pharmacology and Toxicology Section, Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale G. Pieraccini, 50139, Florence, Italy
| | - Carla Ghelardini
- Pharmacology and Toxicology Section, Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale G. Pieraccini, 50139, Florence, Italy
| | - Claudiu T Supuran
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche, University of Florence, Via Ugo Schiff 6, 50019, Sesto Fiorentino, Florence, Italy
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9
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Camargo Castillo MA, de Almeida BA, Wissmann D, Moreira RF, Okano FY, Gonzalez FHD, Soares JF, de Faria Valle S. Viability of erythrocytes in canine packed red blood cells stored in CPDA-1 is related to the presence of Mycoplasma haemocanis. Comp Immunol Microbiol Infect Dis 2023; 97:101982. [PMID: 37120937 DOI: 10.1016/j.cimid.2023.101982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 04/12/2023] [Indexed: 05/02/2023]
Abstract
Hemotropic mycoplasmas are associated with subclinical disease in dogs and should be identified in blood donors. The objective was to investigate the presence and effect of M. haemocanis in units of packed red blood cells (pRBC) during storage. Canine donors (n = 10) were screened for M. haemocanis by quantitative real-time PCR. pRBCs were obtained from 5 hemoplasma negative dogs and 5 hemoplasma positive dogs. Each pRBC was aliquoted into two 100 mL transfer bags and stored at 4 °C. M. haemocanis loads and biochemical variables (pH, bicarbonate, potassium, sodium, chlorite, glucose, lactate, ammonia, PCV, and % hemolysis) were evaluated on days 1, 7, 18, and 29. M. haemocanis loads increased in pRBC from day 1-29 of storage. Glucose decreased and lactate increase faster in pRBC with M. haemocanis. This study contributes to understand hemoplasma metabolism and reinforces that dog donors should be tested for hemoplasmas.
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Affiliation(s)
- Monica A Camargo Castillo
- Department of Veterinary Clinical Pathology, School of Veterinary Medicine, UFRGS, Porto Alegre RS, Brazil
| | | | - Daiani Wissmann
- Department of Veterinary Clinical Pathology, School of Veterinary Medicine, UFRGS, Porto Alegre RS, Brazil
| | - Renata Fagundes Moreira
- Department of Veterinary Clinical Pathology, School of Veterinary Medicine, UFRGS, Porto Alegre RS, Brazil
| | - Felipe Yuki Okano
- Department of Veterinary Clinical Pathology, School of Veterinary Medicine, UFRGS, Porto Alegre RS, Brazil
| | - Felix H D Gonzalez
- Department of Veterinary Clinical Pathology, School of Veterinary Medicine, UFRGS, Porto Alegre RS, Brazil
| | - João Fábio Soares
- Department of Veterinary Clinical Pathology, School of Veterinary Medicine, UFRGS, Porto Alegre RS, Brazil
| | - Stella de Faria Valle
- Department of Veterinary Clinical Pathology, School of Veterinary Medicine, UFRGS, Porto Alegre RS, Brazil.
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10
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Potential Novel Role of Membrane-Associated Carbonic Anhydrases in the Kidney. Int J Mol Sci 2023; 24:ijms24044251. [PMID: 36835660 PMCID: PMC9961601 DOI: 10.3390/ijms24044251] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/06/2023] [Accepted: 02/06/2023] [Indexed: 02/23/2023] Open
Abstract
Carbonic anhydrases (CAs), because they catalyze the interconversion of carbon dioxide (CO2) and water into bicarbonate (HCO3-) and protons (H+), thereby influencing pH, are near the core of virtually all physiological processes in the body. In the kidneys, soluble and membrane-associated CAs and their synergy with acid-base transporters play important roles in urinary acid secretion, the largest component of which is the reabsorption of HCO3- in specific nephron segments. Among these transporters are the Na+-coupled HCO3- transporters (NCBTs) and the Cl--HCO3- exchangers (AEs)-members of the "solute-linked carrier" 4 (SLC4) family. All of these transporters have traditionally been regarded as "HCO3-" transporters. However, recently our group has demonstrated that two of the NCBTs carry CO32- rather than HCO3- and has hypothesized that all NCBTs follow suit. In this review, we examine current knowledge on the role of CAs and "HCO3-" transporters of the SLC4 family in renal acid-base physiology and discuss how our recent findings impact renal acid secretion, including HCO3- reabsorption. Traditionally, investigators have associated CAs with producing or consuming solutes (CO2, HCO3-, and H+) and thus ensuring their efficient transport across cell membranes. In the case of CO32- transport by NCBTs, however, we hypothesize that the role of membrane-associated CAs is not the appreciable production or consumption of substrates but the minimization of pH changes in nanodomains near the membrane.
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Lee SK, Occhipinti R, Moss FJ, Parker MD, Grichtchenko II, Boron WF. Distinguishing among HCO 3- , CO 3= , and H + as Substrates of Proteins That Appear To Be "Bicarbonate" Transporters. J Am Soc Nephrol 2023; 34:40-54. [PMID: 36288904 PMCID: PMC10103014 DOI: 10.1681/asn.2022030289] [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: 03/10/2022] [Accepted: 07/23/2022] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Differentiating among HCO 3- , CO 3= , and H + movements across membranes has long seemed impossible. We now seek to discriminate unambiguously among three alternate mechanisms: the inward flux of 2 HCO 3- (mechanism 1), the inward flux of 1 CO 3= (mechanism 2), and the CO 2 /HCO 3- -stimulated outward flux of 2 H + (mechanism 3). METHODS As a test case, we use electrophysiology and heterologous expression in Xenopus oocytes to examine SLC4 family members that appear to transport "bicarbonate" ("HCO 3- "). RESULTS First, we note that cell-surface carbonic anhydrase should catalyze the forward reaction CO 2 +OH - →HCO 3- if HCO 3- is the substrate; if it is not, the reverse reaction should occur. Monitoring changes in cell-surface pH ( Δ pH S ) with or without cell-surface carbonic anhydrase, we find that the presumed Cl-"HCO 3 " exchanger AE1 (SLC4A1) does indeed transport HCO 3- (mechanism 1) as long supposed, whereas the electrogenic Na/"HCO 3 " cotransporter NBCe1 (SLC4A4) and the electroneutral Na + -driven Cl-"HCO 3 " exchanger NDCBE (SLC4A8) do not. Second, we use mathematical simulations to show that each of the three mechanisms generates unique quantities of H + at the cell surface (measured as Δ pH S ) per charge transported (measured as change in membrane current, ΔIm ). Calibrating ΔpH S /Δ Im in oocytes expressing the H + channel H V 1, we find that our NBCe1 data align closely with predictions of CO 3= transport (mechanism 2), while ruling out HCO 3- (mechanism 1) and CO 2 /HCO 3- -stimulated H + transport (mechanism 3). CONCLUSIONS Our surface chemistry approach makes it possible for the first time to distinguish among HCO 3- , CO 3= , and H + fluxes, thereby providing insight into molecular actions of clinically relevant acid-base transporters and carbonic-anhydrase inhibitors.
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Affiliation(s)
- Seong-Ki Lee
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Rossana Occhipinti
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Fraser J. Moss
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Mark D. Parker
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio
- Department of Physiology and Biophysics, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York
| | | | - Walter F. Boron
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
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12
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Zito F, Bonaventura R, Costa C, Russo R. Carbonic anhydrases in development: morphological observations and gene expression profiling in sea urchin embryos exposed to acetazolamide. Open Biol 2023; 13:220254. [PMID: 36597694 PMCID: PMC9811153 DOI: 10.1098/rsob.220254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Carbonic anhydrases (CANs) are conserved metalloenzymes catalysing the reversible hydration of carbon dioxide into protons and bicarbonate, with important roles in cells physiology. Some CAN-coding genes were found in sea urchin genome, although only one involved in embryonic skeletogenesis was described in Paracentrotus lividus. Here, we investigated gene expression patterns of P. lividus embryos cultured in the presence of acetazolamide (AZ), a CAN inhibitor, to combine morphological defects with their molecular underpinning. CAN inhibition blocked skeletogenesis, affected the spatial/temporal expression of some biomineralization-related genes, inhibited embryos swimming. A comparative analysis on the expression of 127 genes in control and 3 h/24 h AZ-treated embryos, using NanoString technology, showed the differential expression of genes encoding for structural/regulatory proteins, with different embryonic roles: biomineralization, transcriptional regulation, signalling, development and defence response. The study of the differentially expressed genes and the signalling pathways affected, besides in silico analyses and a speculative 'interactomic model', leads to predicting the presence of various CAN isoforms, possibly involved in different physiological processes/activities in sea urchin embryo, and their potential target genes/proteins. Our findings provide new valuable molecular data for further studies in several biological fields: developmental biology (biomineralization, axes patterning), cell differentiation (neural development) and drug toxicology (AZ effects on embryos/tissues).
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Affiliation(s)
- Francesca Zito
- Istituto per la Ricerca e l'Innovazione Biomedica, Consiglio Nazionale delle Ricerche, via Ugo La Malfa 153, Palermo 90146, Italy
| | - Rosa Bonaventura
- Istituto per la Ricerca e l'Innovazione Biomedica, Consiglio Nazionale delle Ricerche, via Ugo La Malfa 153, Palermo 90146, Italy
| | - Caterina Costa
- Istituto per la Ricerca e l'Innovazione Biomedica, Consiglio Nazionale delle Ricerche, via Ugo La Malfa 153, Palermo 90146, Italy
| | - Roberta Russo
- Istituto per la Ricerca e l'Innovazione Biomedica, Consiglio Nazionale delle Ricerche, via Ugo La Malfa 153, Palermo 90146, Italy
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13
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Local Attraction of Substrates and Co-Substrates Enhances Weak Acid and Base Transmembrane Transport. Biomolecules 2022; 12:biom12121794. [PMID: 36551222 PMCID: PMC9775063 DOI: 10.3390/biom12121794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 11/25/2022] [Accepted: 11/28/2022] [Indexed: 12/03/2022] Open
Abstract
The transmembrane transport of weak acid and base metabolites depends on the local pH conditions that affect the protonation status of the substrates and the availability of co-substrates, typically protons. Different protein designs ensure the attraction of substrates and co-substrates to the transporter entry sites. These include electrostatic surface charges on the transport proteins and complexation with seemingly transport-unrelated proteins that provide substrate and/or proton antenna, or enzymatically generate substrates in place. Such protein assemblies affect transport rates and directionality. The lipid membrane surface also collects and transfers protons. The complexity in the various systems enables adjustability and regulation in a given physiological or pathophysiological situation. This review describes experimentally shown principles in the attraction and facilitation of weak acid and base transport substrates, including monocarboxylates, ammonium, bicarbonate, and arsenite, plus protons as a co-substrate.
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14
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Extracellular carbonic anhydrase activity promotes a carbon concentration mechanism in metazoan calcifying cells. Proc Natl Acad Sci U S A 2022; 119:e2203904119. [PMID: 36161891 DOI: 10.1073/pnas.2203904119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many calcifying organisms utilize metabolic CO2 to generate CaCO3 minerals to harden their shells and skeletons. Carbonic anhydrases are evolutionary ancient enzymes that have been proposed to play a key role in the calcification process, with the underlying mechanisms being little understood. Here, we used the calcifying primary mesenchyme cells (PMCs) of sea urchin larva to study the role of cytosolic (iCAs) and extracellular carbonic anhydrases (eCAs) in the cellular carbon concentration mechanism (CCM). Molecular analyses identified iCAs and eCAs in PMCs and highlight the prominent expression of a glycosylphosphatidylinositol-anchored membrane-bound CA (Cara7). Intracellular pH recordings in combination with CO2 pulse experiments demonstrated iCA activity in PMCs. iCA activity measurements, together with pharmacological approaches, revealed an opposing contribution of iCAs and eCAs on the CCM. H+-selective electrodes were used to demonstrate eCA-catalyzed CO2 hydration rates at the cell surface. Knockdown of Cara7 reduced extracellular CO2 hydration rates accompanied by impaired formation of specific skeletal segments. Finally, reduced pHi regulatory capacities during inhibition and knockdown of Cara7 underscore a role of this eCA in cellular HCO3- uptake. This work reveals the function of CAs in the cellular CCM of a marine calcifying animal. Extracellular hydration of metabolic CO2 by Cara7 coupled to HCO3- uptake mechanisms mitigates the loss of carbon and reduces the cellular proton load during the mineralization process. The findings of this work provide insights into the cellular mechanisms of an ancient biological process that is capable of utilizing CO2 to generate a versatile construction material.
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15
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Reithmeier RAF. How to Become a Successful Scientist: the 2022 CSMB Arthur Wynne Gold Medal Lecture. Biochem Cell Biol 2022; 100:371-377. [PMID: 36041226 DOI: 10.1139/bcb-2022-0206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
There are many pathways to success. Mine followed a traditional one to an academic faculty position, but this pathway is not the one most life sciences PhD graduates will follow today. We have all had time during the COVID-19 Pandemic to reflect on our personal pathway -where we are and where we are going. In this reflection I outline five steps on my pathway to success: 1.Train with the best 2.Discover something 3.Mentor others 4.Go beyond 5.Promote science. I will provide examples from my personal journey that I hope will resonant with the reader as they create their pathway to success.
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16
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Sae-Lee W, McCafferty CL, Verbeke EJ, Havugimana PC, Papoulas O, McWhite CD, Houser JR, Vanuytsel K, Murphy GJ, Drew K, Emili A, Taylor DW, Marcotte EM. The protein organization of a red blood cell. Cell Rep 2022; 40:111103. [PMID: 35858567 PMCID: PMC9764456 DOI: 10.1016/j.celrep.2022.111103] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 04/18/2022] [Accepted: 06/24/2022] [Indexed: 11/28/2022] Open
Abstract
Red blood cells (RBCs) (erythrocytes) are the simplest primary human cells, lacking nuclei and major organelles and instead employing about a thousand proteins to dynamically control cellular function and morphology in response to physiological cues. In this study, we define a canonical RBC proteome and interactome using quantitative mass spectrometry and machine learning. Our data reveal an RBC interactome dominated by protein homeostasis, redox biology, cytoskeletal dynamics, and carbon metabolism. We validate protein complexes through electron microscopy and chemical crosslinking and, with these data, build 3D structural models of the ankyrin/Band 3/Band 4.2 complex that bridges the spectrin cytoskeleton to the RBC membrane. The model suggests spring-like compression of ankyrin may contribute to the characteristic RBC cell shape and flexibility. Taken together, our study provides an in-depth view of the global protein organization of human RBCs and serves as a comprehensive resource for future research.
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Affiliation(s)
- Wisath Sae-Lee
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, TX 78712, USA
| | - Caitlyn L McCafferty
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, TX 78712, USA
| | - Eric J Verbeke
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, TX 78712, USA
| | - Pierre C Havugimana
- Center for Network Systems Biology, Boston University, Boston, MA 02118, USA
| | - Ophelia Papoulas
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, TX 78712, USA
| | - Claire D McWhite
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, TX 78712, USA
| | - John R Houser
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, TX 78712, USA
| | - Kim Vanuytsel
- Center for Regenerative Medicine, Boston University School of Medicine, 670 Albany Street, Boston, MA 02118, USA
| | - George J Murphy
- Center for Regenerative Medicine, Boston University School of Medicine, 670 Albany Street, Boston, MA 02118, USA
| | - Kevin Drew
- Department of Biological Sciences, University of Illinois at Chicago, 900 S. Ashland Avenue, Chicago, IL 60607, USA
| | - Andrew Emili
- Center for Network Systems Biology, Boston University, Boston, MA 02118, USA
| | - David W Taylor
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, TX 78712, USA
| | - Edward M Marcotte
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, TX 78712, USA.
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17
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Çol S, Emirik M, Alım Z, Baran A. Physical–chemical studies of new, versatile carbazole derivatives and zinc complexes: Their synthesis, investigation of
in–vitro
inhibitory effects on
α
–glucosidase and human erythrocyte carbonic anhydrase I and II isoenzymes. Appl Organomet Chem 2022. [DOI: 10.1002/aoc.6799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Sümeyye Çol
- Sakarya University, Faculty of Arts and Sciences, Chemistry Department Sakarya Turkey
| | - Mustafa Emirik
- Recep Tayyip Erdoğan University, Faculty of Arts and Sciences, Chemistry Department Rize Turkey
| | - Zuhal Alım
- Ahi Evran University, Faculty of Arts and Sciences, Chemistry Department Kırşehir Turkey
| | - Arif Baran
- Sakarya University, Faculty of Arts and Sciences, Chemistry Department Sakarya Turkey
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18
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Kalli AC, Reithmeier RAF. Organization and Dynamics of the Red Blood Cell Band 3 Anion Exchanger SLC4A1: Insights From Molecular Dynamics Simulations. Front Physiol 2022; 13:817945. [PMID: 35283786 PMCID: PMC8914234 DOI: 10.3389/fphys.2022.817945] [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: 11/18/2021] [Accepted: 01/27/2022] [Indexed: 01/16/2023] Open
Abstract
Molecular dynamics (MD) simulations have provided new insights into the organization and dynamics of the red blood cell Band 3 anion exchanger (AE1, SLC4A1). Band 3, like many solute carriers, works by an alternating access mode of transport where the protein rapidly (104/s) changes its conformation between outward and inward-facing states via a transient occluded anion-bound intermediate. While structural studies of membrane proteins usually reveal valuable structural information, these studies provide a static view often in the presence of detergents. Membrane transporters are embedded in a lipid bilayer and associated lipids play a role in their folding and function. In this review, we highlight MD simulations of Band 3 in realistic lipid bilayers that revealed specific lipid and protein interactions and were used to re-create a model of the Wright (Wr) blood group antigen complex of Band 3 and Glycophorin A. Current MD studies of Band 3 and related transporters are focused on describing the trajectory of substrate binding and translocation in real time. A structure of the intact Band 3 protein has yet to be achieved experimentally, but cryo-electron microscopy in combination with MD simulations holds promise to capture the conformational changes associated with anion transport in exquisite molecular detail.
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Affiliation(s)
- Antreas C. Kalli
- Leeds Institute of Cardiovascular and Metabolic Medicine and Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Reinhart A. F. Reithmeier
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
- *Correspondence: Reinhart A. F. Reithmeier,
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19
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Aspatwar A, Tolvanen MEE, Barker H, Syrjänen L, Valanne S, Purmonen S, Waheed A, Sly WS, Parkkila S. Carbonic Anhydrases in Metazoan Model Organisms: Molecules, Mechanisms, and Physiology. Physiol Rev 2022; 102:1327-1383. [PMID: 35166161 DOI: 10.1152/physrev.00018.2021] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
During the past three decades, mice, zebrafish, fruit flies, and Caenorhabditis elegans have been the primary model organisms used for the study of various biological phenomena. These models have also been adopted and developed to investigate the physiological roles of carbonic anhydrases (CAs) and carbonic anhydrase-related proteins (CARPs). These proteins belong to eight CA families and are identified by Greek letters: α, β, γ, δ, ζ, η, θ, and ι. Studies using model organisms have focused on two CA families, α-CAs and β-CAs, which are expressed in both prokaryotic and eukaryotic organisms with species-specific distribution patterns and unique functions. This review covers the biological roles of CAs and CARPs in light of investigations performed in model organisms. Functional studies demonstrate that CAs are not only linked to the regulation of pH homeostasis, the classical role of CAs but also contribute to a plethora of previously undescribed functions.
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Affiliation(s)
- Ashok Aspatwar
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | | | - Harlan Barker
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland.,Fimlab Ltd and TAYS Cancer Centre, Tampere University Hospital, Tampere, Finland
| | - Leo Syrjänen
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland.,Department of Otorhinolaryngology, Tampere University Hospital, Tampere, Finland
| | - Susanna Valanne
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Sami Purmonen
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Abdul Waheed
- Department of Biochemistry and Molecular Biology, Edward A. Doisy Research Center, Saint Louis University School of Medicine, St. Louis, MO, United States
| | - William S Sly
- Department of Biochemistry and Molecular Biology, Edward A. Doisy Research Center, Saint Louis University School of Medicine, St. Louis, MO, United States
| | - Seppo Parkkila
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland.,Fimlab Ltd and TAYS Cancer Centre, Tampere University Hospital, Tampere, Finland
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20
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Abstract
BACKGROUND The pathogenesis of gastroesophageal reflux disease (GERD) has not been resolved in detail. Esophageal epithelial cells provide resistance to acidic reflux via several mechanisms, many of which involve buffering acid with bicarbonate and transporting protons. Carbonic anhydrases (CAs) are enzymes that control the acid-base balance by catalyzing the reversible hydration of carbon dioxide to produce bicarbonate and hydrogen ions. AIMS We aimed to determine the immunohistochemical expression patterns of CAII, CAIX, and CAXII in the normal esophageal squamous epithelium and in patients with GERD. METHODS We evaluated 82 biopsy samples, including 26 with a histologically normal esophagus, 26 with histologically mild esophagitis, and 30 with severe esophagitis. Expression patterns of CAII, CAIX, and CAXII in the esophageal squamous epithelium were determined by immunohistochemical staining. RESULTS Cytoplasmic CAII expression was predominantly detected in the upper luminal part of the squamous epithelium and was significantly (p < 0.01) increased in GERD. Expression of CAIX was essentially membranous. The isozyme was constantly present in the peripapillary cells. In the interpapillary areas, clustered expression was observed to emerge and increase significantly (p < 0.01) in esophagitis. CAXII expression was the most abundant of the isozymes and was mainly membranous. In the normal squamous epithelium, CAXII expression was confined to the basal layer; in severe esophagitis, CAXII expression increased significantly in both basal (p < 0.05) and superficial (p < 0.01) halves of the epithelium. CONCLUSIONS We demonstrate upregulated expression of CAII, CAIX, and CAXII in GERD. The increase in expression likely contributes to esophageal epithelial resistance to acidic reflux.
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21
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Peña-Münzenmayer G, Kondo Y, Salinas C, Sarmiento J, Brauchi S, Catalán MA. Activation of the Ae4 (Slc4a9) cation-driven Cl -/HCO 3- exchanger by the cAMP-dependent protein kinase in salivary gland acinar cells. Am J Physiol Gastrointest Liver Physiol 2021; 321:G628-G638. [PMID: 34585968 PMCID: PMC8887885 DOI: 10.1152/ajpgi.00145.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 09/24/2021] [Accepted: 09/27/2021] [Indexed: 01/31/2023]
Abstract
Ae4 transporters are critical for Cl- uptake across the basolateral membrane of acinar cells in the submandibular gland (SMG). Although required for fluid secretion, little is known about the physiological regulation of Ae4. To investigate whether Ae4 is regulated by the cAMP-dependent signaling pathway, we measured Cl-/HCO3- exchanger activity in SMG acinar cells from Ae2-/- mice, which only express Ae4, and found that the Ae4-mediated activity was increased in response to β-adrenergic receptor stimulation. Moreover, pretreatment with H89, an inhibitor of the cAMP-activated kinase (PKA), prevented the stimulation of Ae4 exchangers. We then expressed Ae4 in CHO-K1 cells and found that the Ae4-mediated activity was increased when Ae4 is coexpressed with the catalytic subunit of PKA (PKAc), which is constitutively active. Ae4 sequence analysis showed two potential PKA phosphorylation serine residues located at the intracellular NH2-terminal domain according to a homology model of Ae4. NH2-terminal domain Ser residues were mutated to alanine (S173A and S273A, respectively), where the Cl-/HCO3- exchanger activity displayed by the mutant S173A was not activated by PKA. Conversely, S273A mutant kept the PKA dependency. Together, we conclude that Ae4 is stimulated by PKA in SMG acinar cells by a mechanism that probably depends on the phosphorylation of S173.NEW & NOTEWORTHY We found that Ae4 exchanger activity in secretory salivary gland acinar cells is increased upon β-adrenergic receptor stimulation. The activation of Ae4 was prevented by H89, a nonselective PKA inhibitor. Protein sequence analysis revealed two residues (S173 and S273) that are potential targets of cAMP-dependent protein kinase (PKA). Experiments in CHO-K1 cells expressing S173A and S273A mutants showed that S173A, but not S273A, is not activated by PKA.
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Affiliation(s)
- Gaspar Peña-Münzenmayer
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Valdivia, Chile
| | - Yusuke Kondo
- Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Fukuoka, Japan
| | - Constanza Salinas
- Facultad de Medicina, Instituto de Fisiología, Universidad Austral de Chile, Valdivia, Chile
| | - José Sarmiento
- Facultad de Medicina, Instituto de Fisiología, Universidad Austral de Chile, Valdivia, Chile
| | - Sebastián Brauchi
- Facultad de Medicina, Instituto de Fisiología, Universidad Austral de Chile, Valdivia, Chile
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Valdivia, Chile
| | - Marcelo A Catalán
- Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique, Chile
- Facultad de Medicina, Instituto de Fisiología, Universidad Austral de Chile, Valdivia, Chile
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22
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McMahon TJ, Darrow CC, Hoehn BA, Zhu H. Generation and Export of Red Blood Cell ATP in Health and Disease. Front Physiol 2021; 12:754638. [PMID: 34803737 PMCID: PMC8602689 DOI: 10.3389/fphys.2021.754638] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/05/2021] [Indexed: 12/16/2022] Open
Abstract
Metabolic homeostasis in animals depends critically on evolved mechanisms by which red blood cell (RBC) hemoglobin (Hb) senses oxygen (O2) need and responds accordingly. The entwined regulation of ATP production and antioxidant systems within the RBC also exploits Hb-based O2-sensitivity to respond to various physiologic and pathophysiologic stresses. O2 offloading, for example, promotes glycolysis in order to generate both 2,3-DPG (a negative allosteric effector of Hb O2 binding) and ATP. Alternatively, generation of the nicotinamide adenine dinucleotide phosphate (NADPH) critical for reducing systems is favored under the oxidizing conditions of O2 abundance. Dynamic control of ATP not only ensures the functional activity of ion pumps and cellular flexibility, but also contributes to the availability of vasoregulatory ATP that can be exported when necessary, for example in hypoxia or upon RBC deformation in microvessels. RBC ATP export in response to hypoxia or deformation dilates blood vessels in order to promote efficient O2 delivery. The ability of RBCs to adapt to the metabolic environment via differential control of these metabolites is impaired in the face of enzymopathies [pyruvate kinase deficiency; glucose-6-phosphate dehydrogenase (G6PD) deficiency], blood banking, diabetes mellitus, COVID-19 or sepsis, and sickle cell disease. The emerging availability of therapies capable of augmenting RBC ATP, including newly established uses of allosteric effectors and metabolite-specific additive solutions for RBC transfusates, raises the prospect of clinical interventions to optimize or correct RBC function via these metabolite delivery mechanisms.
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Affiliation(s)
- Timothy J McMahon
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, Durham VA and Duke University Medical Centers, Durham, NC, United States
| | - Cole C Darrow
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, Durham VA and Duke University Medical Centers, Durham, NC, United States
| | - Brooke A Hoehn
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, Durham VA and Duke University Medical Centers, Durham, NC, United States
| | - Hongmei Zhu
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, Durham VA and Duke University Medical Centers, Durham, NC, United States
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23
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Jennings ML. Cell Physiology and Molecular Mechanism of Anion Transport by Erythrocyte Band 3/AE1. Am J Physiol Cell Physiol 2021; 321:C1028-C1059. [PMID: 34669510 PMCID: PMC8714990 DOI: 10.1152/ajpcell.00275.2021] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The major transmembrane protein of the red blood cell, known as band 3, AE1, and SLC4A1, has two main functions: 1) catalysis of Cl-/HCO3- exchange, one of the steps in CO2 excretion; 2) anchoring the membrane skeleton. This review summarizes the 150 year history of research on red cell anion transport and band 3 as an experimental system for studying membrane protein structure and ion transport mechanisms. Important early findings were that red cell Cl- transport is a tightly coupled 1:1 exchange and band 3 is labeled by stilbenesulfonate derivatives that inhibit anion transport. Biochemical studies showed that the protein is dimeric or tetrameric (paired dimers) and that there is one stilbenedisulfonate binding site per subunit of the dimer. Transport kinetics and inhibitor characteristics supported the idea that the transporter acts by an alternating access mechanism with intrinsic asymmetry. The sequence of band 3 cDNA provided a framework for detailed study of protein topology and amino acid residues important for transport. The identification of genetic variants produced insights into the roles of band 3 in red cell abnormalities and distal renal tubular acidosis. The publication of the membrane domain crystal structure made it possible to propose concrete molecular models of transport. Future research directions include improving our understanding of the transport mechanism at the molecular level and of the integrative relationships among band 3, hemoglobin, carbonic anhydrase, and gradients (both transmembrane and subcellular) of HCO3-, Cl-, O2, CO2, pH, and NO metabolites during pulmonary and systemic capillary gas exchange.
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Affiliation(s)
- Michael L Jennings
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States
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24
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Nolly MB, Vargas LA, Correa MV, Lofeudo JM, Pinilla AO, Rueda JOV, Guerrero-Gimenez ME, Swenson ER, Damiani MT, Alvarez BV. Carbonic anhydrase IX and hypoxia-inducible factor 1 attenuate cardiac dysfunction after myocardial infarction. Pflugers Arch 2021; 473:1273-1285. [PMID: 34231059 DOI: 10.1007/s00424-021-02592-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/04/2021] [Accepted: 02/08/2021] [Indexed: 01/11/2023]
Abstract
Myocardial infarction (MI) is one of the leading causes of death worldwide. Prognosis and mortality rate are directly related to infarct size and post-infarction pathological heart remodeling, which can lead to heart failure. Hypoxic MI-affected areas increase the expression of hypoxia-inducible factor (HIF-1), inducing infarct size reduction and improving cardiac function. Hypoxia translocates HIF-1 to the nucleus, activating carbonic anhydrase IX (CAIX) transcription. CAIX regulates myocardial intracellular pH, critical for heart performance. Our objective was to investigate CAIX participation and relation with sodium bicarbonate transporters 1 (NBC1) and HIF-1 in cardiac remodeling after MI. We analyzed this pathway in an "in vivo" rat coronary artery ligation model and isolated cardiomyocytes maintained under hypoxia. Immunohistochemical studies revealed an increase in HIF-1 levels after 2 h of infarction. Similar results were observed in 2-h infarcted cardiac tissue (immunoblotting) and in hypoxic cardiomyocytes with a nuclear distribution (confocal microscopy). Immunohistochemical studies showed an increase CAIX in the infarcted area at 2 h, mainly distributed throughout the cell and localized in the plasma membrane at 24 h. Similar results were observed in 2 h in infarcted cardiac tissue (immunoblotting) and in hypoxic cardiomyocytes (confocal microscopy). NBC1 expression increased in cardiac tissue after 2 h of infarction (immunoblotting). CAIX and NBC1 interaction increases in cardiac tissue subjected to MI for 2h when CAIX is present (immunoprecipitation). These results suggest that CAIX interacts with NBC1 in our infarct model as a mechanism to prevent acidic damage in hypoxic tissue, making it a promising therapeutic target.
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Affiliation(s)
- Mariela Beatriz Nolly
- Laboratorio de Bioquímica e Inmunidad, IMBECU-CONICET-UNCuyo, Instituto de Bioquímica y Biotecnología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, 5500, Mendoza, Argentina.
| | - Lorena Alejandra Vargas
- Centro de Investigaciones Cardiovasculares, CIC-CONICET, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, 1900, Buenos Aires, Argentina
| | - María Verónica Correa
- Comisión de Investigaciones Científicas de la Provincia de Buenos Aires, CIC-PBA, La Plata, 1900, Buenos Aires, Argentina
| | - Juan Manuel Lofeudo
- Centro de Investigaciones Cardiovasculares, CIC-CONICET, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, 1900, Buenos Aires, Argentina
| | - Andrés Oscar Pinilla
- Centro de Investigaciones Cardiovasculares, CIC-CONICET, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, 1900, Buenos Aires, Argentina
| | - Jorge Omar Velez Rueda
- Centro de Investigaciones Cardiovasculares, CIC-CONICET, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, 1900, Buenos Aires, Argentina
| | - Martin E Guerrero-Gimenez
- Laboratorio de Oncología, IMBECU-CONICET-UNCuyo, Instituto de Bioquímica y Biotecnología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, 5500, Mendoza, Argentina
| | - Erik Richard Swenson
- Medical Service, VA Puget Sound Health Care System, University of Washington, Seattle, WA, USA
| | - Maria Teresa Damiani
- Laboratorio de Bioquímica e Inmunidad, IMBECU-CONICET-UNCuyo, Instituto de Bioquímica y Biotecnología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, 5500, Mendoza, Argentina
| | - Bernardo Victor Alvarez
- Centro de Investigaciones Cardiovasculares, CIC-CONICET, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, 1900, Buenos Aires, Argentina
- Department of Biochemistry, Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
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25
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Khosrowabadi E, Rivinoja A, Risteli M, Tuomisto A, Salo T, Mäkinen MJ, Kellokumpu S. SLC4A2 anion exchanger promotes tumour cell malignancy via enhancing net acid efflux across golgi membranes. Cell Mol Life Sci 2021; 78:6283-6304. [PMID: 34279699 PMCID: PMC8429400 DOI: 10.1007/s00018-021-03890-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 06/08/2021] [Accepted: 06/25/2021] [Indexed: 12/27/2022]
Abstract
Proper functioning of each secretory and endocytic compartment relies on its unique pH micro-environment that is known to be dictated by the rates of V-ATPase-mediated H+ pumping and its leakage back to the cytoplasm via an elusive "H+ leak" pathway. Here, we show that this proton leak across Golgi membranes is mediated by the AE2a (SLC4A2a)-mediated bicarbonate-chloride exchange, as it is strictly dependent on bicarbonate import (in exchange for chloride export) and the expression level of the Golgi-localized AE2a anion exchanger. In the acidic Golgi lumen, imported bicarbonate anions and protons then facilitate a common buffering reaction that yields carbon dioxide and water before their egress back to the cytoplasm via diffusion or water channels. The flattened morphology of the Golgi cisternae helps this process, as their high surface-volume ratio is optimal for water and gas exchange. Interestingly, this net acid efflux pathway is often upregulated in cancers and established cancer cell lines, and responsible for their markedly elevated Golgi resting pH and attenuated glycosylation potential. Accordingly, AE2 knockdown in SW-48 colorectal cancer cells was able to restore these two phenomena, and at the same time, reverse their invasive and anchorage-independent growth phenotype. These findings suggest a possibility to return malignant cells to a benign state by restoring Golgi resting pH.
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Affiliation(s)
- Elham Khosrowabadi
- Faculty of Biochemistry and Molecular Medicine, University of Oulu (Oulun Yliopisto), Aapistie 7A, PO BOX 5400, 90014, Oulu, Finland.
| | | | - Maija Risteli
- Cancer and Translational Medicine Research Unit, University of Oulu, Oulu, Finland.,Medical Research Centre, Oulu University Hospital, Oulu, Finland
| | - Anne Tuomisto
- Medical Research Centre, Oulu University Hospital, Oulu, Finland
| | - Tuula Salo
- Cancer and Translational Medicine Research Unit, University of Oulu, Oulu, Finland.,Medical Research Centre, Oulu University Hospital, Oulu, Finland
| | - Markus J Mäkinen
- Medical Research Centre, Oulu University Hospital, Oulu, Finland
| | - Sakari Kellokumpu
- Faculty of Biochemistry and Molecular Medicine, University of Oulu (Oulun Yliopisto), Aapistie 7A, PO BOX 5400, 90014, Oulu, Finland.
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26
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Takei Y. The digestive tract as an essential organ for water acquisition in marine teleosts: lessons from euryhaline eels. ZOOLOGICAL LETTERS 2021; 7:10. [PMID: 34154668 PMCID: PMC8215749 DOI: 10.1186/s40851-021-00175-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 04/16/2021] [Indexed: 05/17/2023]
Abstract
Adaptation to a hypertonic marine environment is one of the major topics in animal physiology research. Marine teleosts lose water osmotically from the gills and compensate for this loss by drinking surrounding seawater and absorbing water from the intestine. This situation is in contrast to that in mammals, which experience a net osmotic loss of water after drinking seawater. Water absorption in fishes is made possible by (1) removal of monovalent ions (desalinization) by the esophagus, (2) removal of divalent ions as carbonate (Mg/CaCO3) precipitates promoted by HCO3- secretion, and (3) facilitation of NaCl and water absorption from diluted seawater by the intestine using a suite of unique transporters. As a result, 70-85% of ingested seawater is absorbed during its passage through the digestive tract. Thus, the digestive tract is an essential organ for marine teleost survival in the hypertonic seawater environment. The eel is a species that has been frequently used for osmoregulation research in laboratories worldwide. The eel possesses many advantages as an experimental animal for osmoregulation studies, one of which is its outstanding euryhalinity, which enables researchers to examine changes in the structure and function of the digestive tract after direct transfer from freshwater to seawater. In recent years, the molecular mechanisms of ion and water transport across epithelial cells (the transcellular route) and through tight junctions (the paracellular route) have been elucidated for the esophagus and intestine. Thanks to the rapid progress in analytical methods for genome databases on teleosts, including the eel, the molecular identities of transporters, channels, pumps and junctional proteins have been clarified at the isoform level. As 10 y have passed since the previous reviews on this subject, it seems relevant and timely to summarize recent progress in research on the molecular mechanisms of water and ion transport in the digestive tract in eels and to compare the mechanisms with those of other teleosts and mammals from comparative and evolutionary viewpoints. We also propose future directions for this research field to achieve integrative understanding of the role of the digestive tract in adaptation to seawater with regard to pathways/mechanisms including the paracellular route, divalent ion absorption, metabolon formation and cellular trafficking of transporters. Notably, some of these have already attracted practical attention in laboratories.
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Affiliation(s)
- Yoshio Takei
- Laboratory of Physiology, Department of Marine Bioscience, Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan.
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27
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Galenkamp KMO, Commisso C. The Golgi as a "Proton Sink" in Cancer. Front Cell Dev Biol 2021; 9:664295. [PMID: 34055797 PMCID: PMC8155353 DOI: 10.3389/fcell.2021.664295] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 04/21/2021] [Indexed: 12/19/2022] Open
Abstract
Cancer cells exhibit increased glycolytic flux and adenosine triphosphate (ATP) hydrolysis. These processes increase the acidic burden on the cells through the production of lactate and protons. Nonetheless, cancer cells can maintain an alkaline intracellular pH (pHi) relative to untransformed cells, which sets the stage for optimal functioning of glycolytic enzymes, evasion of cell death, and increased proliferation and motility. Upregulation of plasma membrane transporters allows for H+ and lactate efflux; however, recent evidence suggests that the acidification of organelles can contribute to maintenance of an alkaline cytosol in cancer cells by siphoning off protons, thereby supporting tumor growth. The Golgi is such an acidic organelle, with resting pH ranging from 6.0 to 6.7. Here, we posit that the Golgi represents a "proton sink" in cancer and delineate the proton channels involved in Golgi acidification and the ion channels that influence this process. Furthermore, we discuss ion channel regulators that can affect Golgi pH and Golgi-dependent processes that may contribute to pHi homeostasis in cancer.
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Affiliation(s)
- Koen M. O. Galenkamp
- Cell and Molecular Biology of Cancer Program, NCI-Designated Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, United States
| | - Cosimo Commisso
- Cell and Molecular Biology of Cancer Program, NCI-Designated Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, United States
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28
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Remigante A, Morabito R, Marino A. Band 3 protein function and oxidative stress in erythrocytes. J Cell Physiol 2021; 236:6225-6234. [PMID: 33559172 DOI: 10.1002/jcp.30322] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 01/24/2021] [Accepted: 01/28/2021] [Indexed: 12/17/2022]
Abstract
Band 3 protein (B3p), anion transporter, allows the HCO3 - /Cl- exchange across plasma membrane and plays an important role for erythrocytes homeostasis. In addition, B3p is linked to proteins cytoskeleton, thus contributing to cell shape and deformability, essential to erythrocytes adjustment within narrowest capillaries. Taking into account that erythrocytes are a suitable cell model to investigate the response of the oxidative stress effects, B3p functions, and specifically anion exchange capability, determining the rate constant for SO4 2- uptake, has been considered. As, in the latter years, rising attention has been addressed to membrane transport system, and particularly to this protein, the present mini-review has been conceived to report the most recent knowledge about B3p, with specific regard to its functions in oxidative stress conditions, including oxidative stress-related diseases.
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Affiliation(s)
- Alessia Remigante
- Institute of Biophysics, National Research Council, Genoa, Italy.,Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Rossana Morabito
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Angela Marino
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
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29
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Trampert DC, van de Graaf SFJ, Jongejan A, Oude Elferink RPJ, Beuers U. Hepatobiliary acid-base homeostasis: Insights from analogous secretory epithelia. J Hepatol 2021; 74:428-441. [PMID: 33342564 DOI: 10.1016/j.jhep.2020.10.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 10/03/2020] [Accepted: 10/19/2020] [Indexed: 12/14/2022]
Abstract
Many epithelia secrete bicarbonate-rich fluid to generate flow, alter viscosity, control pH and potentially protect luminal and intracellular structures from chemical stress. Bicarbonate is a key component of human bile and impaired biliary bicarbonate secretion is associated with liver damage. Major efforts have been undertaken to gain insight into acid-base homeostasis in cholangiocytes and more can be learned from analogous secretory epithelia. Extrahepatic examples include salivary and pancreatic duct cells, duodenocytes, airway and renal epithelial cells. The cellular machinery involved in acid-base homeostasis includes carbonic anhydrase enzymes, transporters of the solute carrier family, and intra- and extracellular pH sensors. This pH-regulatory system is orchestrated by protein-protein interactions, the establishment of an electrochemical gradient across the plasma membrane and bicarbonate sensing of the intra- and extracellular compartment. In this review, we discuss conserved principles identified in analogous secretory epithelia in the light of current knowledge on cholangiocyte physiology. We present a framework for cholangiocellular acid-base homeostasis supported by expression analysis of publicly available single-cell RNA sequencing datasets from human cholangiocytes, which provide insights into the molecular basis of pH homeostasis and dysregulation in the biliary system.
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Affiliation(s)
- David C Trampert
- Amsterdam UMC, University of Amsterdam, Department of Gastroenterology and Hepatology, Tytgat Institute for Liver and Intestinal Research, Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Meibergdreef 9, Amsterdam, the Netherlands
| | - Stan F J van de Graaf
- Amsterdam UMC, University of Amsterdam, Department of Gastroenterology and Hepatology, Tytgat Institute for Liver and Intestinal Research, Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Meibergdreef 9, Amsterdam, the Netherlands
| | - Aldo Jongejan
- Amsterdam UMC, University of Amsterdam, Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Meibergdreef 9, Amsterdam, the Netherlands
| | - Ronald P J Oude Elferink
- Amsterdam UMC, University of Amsterdam, Department of Gastroenterology and Hepatology, Tytgat Institute for Liver and Intestinal Research, Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Meibergdreef 9, Amsterdam, the Netherlands
| | - Ulrich Beuers
- Amsterdam UMC, University of Amsterdam, Department of Gastroenterology and Hepatology, Tytgat Institute for Liver and Intestinal Research, Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Meibergdreef 9, Amsterdam, the Netherlands.
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30
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Kumar S, Rulhania S, Jaswal S, Monga V. Recent advances in the medicinal chemistry of carbonic anhydrase inhibitors. Eur J Med Chem 2021; 209:112923. [PMID: 33121862 DOI: 10.1016/j.ejmech.2020.112923] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 10/05/2020] [Accepted: 10/07/2020] [Indexed: 02/08/2023]
Abstract
Carbonic anhydrase (CA, EC 4.2.1.1) is an enzyme and a very omnipresent zinc metalloenzyme which catalyzed the reversible hydration and dehydration of carbon dioxide and bicarbonate; a reaction which plays a crucial role in many physiological and pathological processes. Carbonic anhydrase is present in human (h) with sixteen different isoforms ranging from hCA I-hCA XV. All these isoforms are widely distributed in different tissues/organs and are associated with a range of pivotal physiological activities. Due to their involvement in various physiological roles, inhibitors of different human isoforms of carbonic anhydrase have found clinical applications for the treatment of various diseases including glaucoma, retinopathy, hemolytic anemia, epilepsy, obesity, and cancer. However, clinically used inhibitors of CA (acetazolamide, brinzolamide, dorzolamide, etc.) are not selective causing the undesirable side effects. One of the major hurdles in the design and development of carbonic anhydrase inhibitors is the lack of balanced isoform selectivity which thrived to new chemotypes. In this review, we have compiled the recent strategies of various researchers related to the development of carbonic anhydrase inhibitors belonging to different structural classes like pyrimidine, pyrazoline, selenourea, isatin, indole, etc. This review also summarizes the structure-activity relationships, analysis of isoform selectivity including mechanistic and in silico studies to afford ideas and to provide focused direction for the design and development of novel isoform-selective carbonic anhydrase inhibitors with therapeutic implications.
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Affiliation(s)
- Shubham Kumar
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, GT Road, Ghal Kalan, Moga, 142001, Punjab, India
| | - Sandeep Rulhania
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, GT Road, Ghal Kalan, Moga, 142001, Punjab, India
| | - Shalini Jaswal
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, GT Road, Ghal Kalan, Moga, 142001, Punjab, India
| | - Vikramdeep Monga
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, GT Road, Ghal Kalan, Moga, 142001, Punjab, India.
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31
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Magder S, Magder A, Samoukovic G. Intracellular pH regulation and the acid delusion. Can J Physiol Pharmacol 2020; 99:561-576. [PMID: 33356898 DOI: 10.1139/cjpp-2020-0631] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The hydrogen ion concentration ([H+]) in intracellular cytoplasmic fluid (ICF) must be maintained in a narrow range in all species for normal protein functions. Thus, mechanisms regulating ICF are of fundamental biological importance. Studies on the regulation of ICF [H+] have been hampered by use of pH notation, failure to consider the roles played by differences in the concentration of strong ions (strong ion difference, SID), the conservation of mass, the principle of electrical neutrality, and that [H+] and bicarbonate ions [HCO3-] are dependent variables. This argument is based on the late Peter Stewart's physical-chemical analysis of [H+] regulation reported in this journal nearly forty years ago (Stewart. 1983. Can. J. Physiol. Pharmacol. 61: 1444-1461. Doi:10.1139/y83-207). We start by outlining the principles of Stewart's analysis and then provide a general understanding of its significance for regulation of ICF [H+]. The system may initially appear complex, but it becomes evident that changes in SID dominate regulation of [H+]. The primary strong ions are Na+, K+, and Cl-, and a few organic strong anions. The second independent variable, partial pressure of carbon dioxide (PCO2), can easily be assessed. The third independent variable, the activity of intracellular weak acids ([Atot]), is much more complex but largely plays a modifying role. Attention to these principles will potentially provide new insights into ICF pH regulation.
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Affiliation(s)
- Sheldon Magder
- Department of Critical Care, McGill University Health Centre, 1001 Decarie Blvd, Montreal, QC H4A 3J1, Canada.,Department of Critical Care, McGill University Health Centre, 1001 Decarie Blvd, Montreal, QC H4A 3J1, Canada
| | - Alexandr Magder
- Department of Critical Care, McGill University Health Centre, 1001 Decarie Blvd, Montreal, QC H4A 3J1, Canada.,Department of Critical Care, McGill University Health Centre, 1001 Decarie Blvd, Montreal, QC H4A 3J1, Canada
| | - Gordan Samoukovic
- Department of Critical Care, McGill University Health Centre, 1001 Decarie Blvd, Montreal, QC H4A 3J1, Canada.,Department of Critical Care, McGill University Health Centre, 1001 Decarie Blvd, Montreal, QC H4A 3J1, Canada
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32
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Koltai T. Targeting the pH Paradigm at the Bedside: A Practical Approach. Int J Mol Sci 2020; 21:E9221. [PMID: 33287221 PMCID: PMC7730959 DOI: 10.3390/ijms21239221] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 11/27/2020] [Accepted: 11/28/2020] [Indexed: 02/07/2023] Open
Abstract
The inversion of the pH gradient in malignant tumors, known as the pH paradigm, is increasingly becoming accepted by the scientific community as a hallmark of cancer. Accumulated evidence shows that this is not simply a metabolic consequence of a dysregulated behavior, but rather an essential process in the physiopathology of accelerated proliferation and invasion. From the over-simplification of increased lactate production as the cause of the paradigm, as initially proposed, basic science researchers have arrived at highly complex and far-reaching knowledge, that substantially modified that initial belief. These new developments show that the paradigm entails a different regulation of membrane transporters, electrolyte exchangers, cellular and membrane enzymes, water trafficking, specialized membrane structures, transcription factors, and metabolic changes that go far beyond fermentative glycolysis. This complex world of dysregulations is still shuttered behind the walls of experimental laboratories and has not yet reached bedside medicine. However, there are many known pharmaceuticals and nutraceuticals that are capable of targeting the pH paradigm. Most of these products are well known, have low toxicity, and are also inexpensive. They need to be repurposed, and this would entail shorter clinical studies and enormous cost savings if we compare them with the time and expense required for the development of a new molecule. Will targeting the pH paradigm solve the "cancer problem"? Absolutely not. However, reversing the pH inversion would strongly enhance standard treatments, rendering them more efficient, and in some cases permitting lower doses of toxic drugs. This article's goal is to describe how to reverse the pH gradient inversion with existing drugs and nutraceuticals that can easily be used in bedside medicine, without adding toxicity to established treatments. It also aims at increasing awareness among practicing physicians that targeting the pH paradigm would be able to improve the results of standard therapies. Some clinical cases will be presented as well, showing how the pH gradient inversion can be treated at the bedside in a simple manner with repurposed drugs.
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Affiliation(s)
- Tomas Koltai
- Centro de Diagnostico y Tratamiento de la Obra Social del Personal de la Alimentacion, Talar de Pacheco, Buenos Aires 1617, Argentina
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33
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Moss FJ, Boron WF. Carbonic anhydrases enhance activity of endogenous Na-H exchangers and not the electrogenic Na/HCO 3 cotransporter NBCe1-A, expressed in Xenopus oocytes. J Physiol 2020; 598:5821-5856. [PMID: 32969493 PMCID: PMC7747792 DOI: 10.1113/jp280143] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 09/07/2020] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS According to the HCO 3 - metabolon hypothesis, direct association of cytosolic carbonic anhydrases (CAs) with the electrogenic Na/HCO3 cotransporter NBCe1-A speeds transport by regenerating/consuming HCO 3 - . The present work addresses published discrepancies as to whether cytosolic CAs stimulate NBCe1-A, heterologously expressed in Xenopus oocytes. We confirm the essential elements of the previous experimental observations, taken as support for the HCO 3 - metabolon hypothesis. However, using our own experimental protocols or those of others, we find that NBCe1-A function is unaffected by cytosolic CAs. Previous conclusions that cytosolic CAs do stimulate NBCe1-A can be explained by an unanticipated stimulatory effect of the CAs on an endogenous Na-H exchanger. Theoretical analyses show that, although CAs could stimulate non- HCO 3 - transporters (e.g. Na-H exchangers) by accelerating CO2 / HCO 3 - -mediated buffering of acid-base equivalents, they could not appreciably affect transport rates of NBCe1 or other transporters carrying HCO 3 - , CO 3 = , or NaCO 3 - ion pairs. ABSTRACT The HCO 3 - metabolon hypothesis predicts that cytosolic carbonic anhydrase (CA) binds to NBCe1-A, promotes HCO 3 - replenishment/consumption, and enhances transport. Using a short step-duration current-voltage (I-V) protocol with Xenopus oocytes expressing eGFP-tagged NBCe1-A, our group reported that neither injecting human CA II (hCA II) nor fusing hCA II to the NBCe1-A carboxy terminus affects background-subtracted NBCe1 slope conductance (GNBC ), which is a direct measure of NBCe1-A activity. Others - using bovine CA (bCA), untagged NBCe1-A, and protocols keeping holding potential (Vh ) far from NBCe1-A's reversal potential (Erev ) for prolonged periods - found that bCA increases total membrane current (ΔIm ), which apparently supports the metabolon hypothesis. We systematically investigated differences in the two protocols. In oocytes expressing untagged NBCe1-A, injected with bCA and clamped to -40 mV, CO2 / HCO 3 - exposures markedly decrease Erev , producing large transient outward currents persisting for >10 min and rapid increases in [Na+ ]i . Although the CA inhibitor ethoxzolamide (EZA) reduces both ΔIm and d[Na+ ]i /dt, it does not reduce GNBC . In oocytes not expressing NBCe1-A, CO2 / HCO 3 - triggers rapid increases in [Na+ ]i that both hCA II and bCA enhance in concentration-dependent manners. These d[Na+ ]i /dt increases are inhibited by EZA and blocked by EIPA, a Na-H exchanger (NHE) inhibitor. In oocytes expressing untagged NBCe1-A and injected with bCA, EIPA abolishes the EZA-dependent decreases in ΔIm and d[Na+ ]i /dt. Thus, CAs/EZA produce their ΔIm and d[Na+ ]i /dt effects not through NBCe1-A, but endogenous NHEs. Theoretical considerations argue against a CA stimulation of HCO 3 - transport, supporting the conclusion that an NBCe1-A- HCO 3 - metabolon does not exist in oocytes.
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Affiliation(s)
- Fraser J. Moss
- Department of Physiology and Biophysics, Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Walter F. Boron
- Department of Physiology and Biophysics, Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- Department of Medicine and Department of Biochemistry Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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34
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Liu X, Gygi SP, Paulo JA. Isobaric Tag-Based Protein Profiling across Eight Human Cell Lines Using High-Field Asymmetric Ion Mobility Spectrometry and Real-Time Database Searching. Proteomics 2020; 21:e2000218. [PMID: 33015980 DOI: 10.1002/pmic.202000218] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/26/2020] [Indexed: 12/11/2022]
Abstract
A vast number of human cell lines are available for cell culture model-based studies, and as such the potential exists for discrepancies in findings due to cell line selection. To investigate this concept, the authors determine the relative protein abundance profiles of a panel of eight diverse, but commonly studied human cell lines. This panel includes HAP1, HEK293T, HeLa, HepG2, Jurkat, Panc1, SH-SY5Y, and SVGp12. A mass spectrometry-based proteomics workflow designed to enhance quantitative accuracy while maintaining analytical depth is used. To this end, this strategy leverages TMTpro16-based sample multiplexing, high-field asymmetric ion mobility spectrometry, and real-time database searching. The data show that the differences in the relative protein abundance profiles reflect cell line diversity. The authors also determine several hundred proteins to be highly enriched for a given cell line, and perform gene ontology and pathway analysis on these cell line-enriched proteins. An R Shiny application is designed to query protein abundance profiles and retrieve proteins with similar patterns. The workflows used herein can be applied to additional cell lines to aid cell line selection for addressing a given scientific inquiry or for improving an experimental design.
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Affiliation(s)
- Xinyue Liu
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Joao A Paulo
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
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35
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Praetorius J. The devil is in the C-tail: a NBCe1-carbonic anhydrase bicarbonate transport metabolon? J Physiol 2020; 598:5595-5596. [PMID: 33043431 DOI: 10.1113/jp280778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 10/05/2020] [Indexed: 11/08/2022] Open
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36
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Huang W, Han S, Jiang H, Gu S, Li W, Gontero B, Maberly SC. External α-carbonic anhydrase and solute carrier 4 are required for bicarbonate uptake in a freshwater angiosperm. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:6004-6014. [PMID: 32721017 DOI: 10.1093/jxb/eraa351] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 07/31/2020] [Indexed: 06/11/2023]
Abstract
The freshwater monocot Ottelia alismoides is the only known species to operate three CO2-concentrating mechanisms (CCMs): constitutive bicarbonate (HCO3-) use, C4 photosynthesis, and facultative Crassulacean acid metabolism, but the mechanism of HCO3- use is unknown. We found that the inhibitor of an anion exchange protein, 4,4'-diisothio-cyanatostilbene-2,2'-disulfonate (DIDS), prevented HCO3- use but also had a small effect on CO2 uptake. An inhibitor of external carbonic anhydrase (CA), acetazolamide (AZ), reduced the affinity for CO2 uptake but also prevented HCO3- use via an effect on the anion exchange protein. Analysis of mRNA transcripts identified a homologue of solute carrier 4 (SLC4) responsible for HCO3- transport, likely to be the target of DIDS, and a periplasmic α-carbonic anhydrase 1 (α-CA1). A model to quantify the contribution of the three different pathways involved in inorganic carbon uptake showed that passive CO2 diffusion dominates inorganic carbon uptake at high CO2 concentrations. However, as CO2 concentrations fall, two other pathways become predominant: conversion of HCO3- to CO2 at the plasmalemma by α-CA1 and transport of HCO3- across the plasmalemma by SLC4. These mechanisms allow access to a much larger proportion of the inorganic carbon pool and continued photosynthesis during periods of strong carbon depletion in productive ecosystems.
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Affiliation(s)
- Wenmin Huang
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan, China
- Aix Marseille Univ CNRS, BIP UMR 7281, IMM, FR 3479, 31 Chemin Joseph Aiguier, Marseille Cedex 20, France
| | - Shijuan Han
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Hongsheng Jiang
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan, China
| | - Shuping Gu
- Shanghai Sequen Bio-info Studio, Shanghai, China
| | - Wei Li
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan, China
| | - Brigitte Gontero
- Aix Marseille Univ CNRS, BIP UMR 7281, IMM, FR 3479, 31 Chemin Joseph Aiguier, Marseille Cedex 20, France
| | - Stephen C Maberly
- Lake Ecosystems Group, UK Centre for Ecology & Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster, UK
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37
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Alam P, Amlal S, Thakar CV, Amlal H. Acetazolamide causes renal [Formula: see text] wasting but inhibits ammoniagenesis and prevents the correction of metabolic acidosis by the kidney. Am J Physiol Renal Physiol 2020; 319:F366-F379. [PMID: 32657159 PMCID: PMC7509283 DOI: 10.1152/ajprenal.00501.2019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 07/05/2020] [Accepted: 07/06/2020] [Indexed: 11/22/2022] Open
Abstract
Carbonic anhydrase (CAII) binds to the electrogenic basolateral Na+-[Formula: see text] cotransporter (NBCe1) and facilitates [Formula: see text] reabsorption across the proximal tubule. However, whether the inhibition of CAII with acetazolamide (ACTZ) alters NBCe1 activity and interferes with the ammoniagenesis pathway remains elusive. To address this issue, we compared the renal adaptation of rats treated with ACTZ to NH4Cl loading for up to 2 wk. The results indicated that ACTZ-treated rats exhibited a sustained metabolic acidosis for up to 2 wk, whereas in NH4Cl-loaded rats, metabolic acidosis was corrected within 2 wk of treatment. [Formula: see text] excretion increased by 10-fold in NH4Cl-loaded rats but only slightly (1.7-fold) in ACTZ-treated rats during the first week despite a similar degree of acidosis. Immunoblot experiments showed that the protein abundance of glutaminase (4-fold), glutamate dehydrogenase (6-fold), and SN1 (8-fold) increased significantly in NH4Cl-loaded rats but remained unchanged in ACTZ-treated rats. Na+/H+ exchanger 3 and NBCe1 proteins were upregulated in response to NH4Cl loading but not ACTZ treatment and were rather sharply downregulated after 2 wk of ACTZ treatment. ACTZ causes renal [Formula: see text] wasting and induces metabolic acidosis but inhibits the upregulation of glutamine transporter and ammoniagenic enzymes and thus suppresses ammonia synthesis and secretion in the proximal tubule, which prevented the correction of acidosis. This effect is likely mediated through the inhibition of the CA-NBCe1 metabolon complex, which results in cell alkalinization. During chronic ACTZ treatment, the downregulation of both NBCe1 and Na+/H+ exchanger 3, along with the inhibition of ammoniagenesis and [Formula: see text] generation, contributes to the maintenance of metabolic acidosis.
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Affiliation(s)
- Perwez Alam
- Division of Nephrology and Kidney C.A.R.E, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio
- Department of Pathology and Laboratory Medicine, College of Medicine, University of Cincinnati, Cincinnati, Ohio
| | - Sihame Amlal
- Division of Nephrology and Kidney C.A.R.E, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio
| | - Charuhas V Thakar
- Division of Nephrology and Kidney C.A.R.E, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio
| | - Hassane Amlal
- Division of Nephrology and Kidney C.A.R.E, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio
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Zheng T, Jäättelä M, Liu B. pH gradient reversal fuels cancer progression. Int J Biochem Cell Biol 2020; 125:105796. [DOI: 10.1016/j.biocel.2020.105796] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 06/19/2020] [Accepted: 06/24/2020] [Indexed: 12/18/2022]
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Becker HM, Deitmer JW. Transport Metabolons and Acid/Base Balance in Tumor Cells. Cancers (Basel) 2020; 12:cancers12040899. [PMID: 32272695 PMCID: PMC7226098 DOI: 10.3390/cancers12040899] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/03/2020] [Accepted: 04/04/2020] [Indexed: 02/07/2023] Open
Abstract
Solid tumors are metabolically highly active tissues, which produce large amounts of acid. The acid/base balance in tumor cells is regulated by the concerted interplay between a variety of membrane transporters and carbonic anhydrases (CAs), which cooperate to produce an alkaline intracellular, and an acidic extracellular, environment, in which cancer cells can outcompete their adjacent host cells. Many acid/base transporters form a structural and functional complex with CAs, coined "transport metabolon". Transport metabolons with bicarbonate transporters require the binding of CA to the transporter and CA enzymatic activity. In cancer cells, these bicarbonate transport metabolons have been attributed a role in pH regulation and cell migration. Another type of transport metabolon is formed between CAs and monocarboxylate transporters, which mediate proton-coupled lactate transport across the cell membrane. In this complex, CAs function as "proton antenna" for the transporter, which mediate the rapid exchange of protons between the transporter and the surroundings. These transport metabolons do not require CA catalytic activity, and support the rapid efflux of lactate and protons from hypoxic cancer cells to allow sustained glycolytic activity and cell proliferation. Due to their prominent role in tumor acid/base regulation and metabolism, transport metabolons might be promising drug targets for new approaches in cancer therapy.
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Affiliation(s)
- Holger M. Becker
- Institute of Physiological Chemistry, University of Veterinary Medicine Hannover, D-30559 Hannover, Germany
- Correspondence:
| | - Joachim W. Deitmer
- Department of Biology, University of Kaiserslautern, D-67653 Kaiserslautern, Germany;
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A Novel Genetically Encoded Single Use Sensory Cellular Test System Measures Bicarbonate Concentration Changes in Living Cells. SENSORS 2020; 20:s20061570. [PMID: 32168979 PMCID: PMC7146495 DOI: 10.3390/s20061570] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 03/06/2020] [Accepted: 03/09/2020] [Indexed: 12/17/2022]
Abstract
Bicarbonate plays a central role in human physiology from cellular respiration to pH homeostasis. However, so far, the measurement of bicarbonate concentration changes in living cells has only been possible by measuring intracellular pH changes. In this article, we report the development of a genetically encoded pH-independent fluorescence-based single-use sensory cellular test system for monitoring intracellular bicarbonate concentration changes in living cells. We describe the usefulness of the developed biosensor in characterizing the bicarbonate transport activities of anionophores-small molecules capable of facilitating the membrane permeation of this anion. We also demonstrate the ability of the bicarbonate sensory cellular test system to measure intracellular bicarbonate concentration changes in response to activation and specific inhibition of wild-type human CFTR protein when co-expressed with the bicarbonate sensing and reporting units in living cells. A valuable benefit of the bicarbonate sensory cellular test system could be the screening of novel anionophore library compounds for bicarbonate transport activity with efficiencies close to the natural anion channel CFTR, which is not functional in the respiratory epithelia of cystic fibrosis patients.
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Abstract
Oxygen (O2) delivery, which is fundamental to supporting patients with critical illness, is a function of blood O2 content and flow. This article reviews red blood cell (RBC) physiology and dysfunction relevant to disordered O2 delivery in the critically ill. Flow is the focus of O2 delivery regulation: O2 content is relatively fixed, whereas flow fluctuates greatly. Thus, blood flow volume and distribution vary to maintain coupling between O2 delivery and demand. This article reviews conventional RBC physiology influencing O2 delivery and introduces a paradigm for O2 delivery homeostasis based on coordinated gas transport and vascular signaling by RBCs.
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Affiliation(s)
- Stephen Rogers
- Department of Pediatrics, Center for Blood Oxygen Transport and Hemostasis, University of Maryland School of Medicine, HSF III, 8th Floor, 670 West Baltimore Street, Baltimore, MD 21204, USA
| | - Allan Doctor
- Department of Pediatrics, Center for Blood Oxygen Transport and Hemostasis, University of Maryland School of Medicine, HSF III, 8th Floor, 670 West Baltimore Street, Baltimore, MD 21204, USA.
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Qin L, Nie Y, Zhang H, Chen L, Zhang D, Lin Y, Ru K. Identification of new mutations in patients with hereditary spherocytosis by next-generation sequencing. J Hum Genet 2020; 65:427-434. [PMID: 31980736 DOI: 10.1038/s10038-020-0724-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 01/04/2020] [Accepted: 01/06/2020] [Indexed: 11/09/2022]
Abstract
Hereditary spherocytosis (HS) is the most common inherited hemolytic anemia characterized by the presence of spherical-shaped erythrocytes on the peripheral blood smear, hemolysis, splenomegaly, jaundice, and gallstones. To date, mutations in at least five genes (ANK1, EPB42, SLC4A1, SPTA1, and SPTB) have been found to be associated with different subtypes of HS. Here, we aim to investigate the presence of novel as well as known mutations in 35 Chinese patients with clinically suspected HS. Whole-exome sequencing (WES) has identified 3 patients with SLC4A1, 16 patients with ANK1, and 16 patients with SPTB mutations, including 5 splicing, 12 nonsense, 9 frameshift, 7 missense, and 1 start-loss mutation, indicating that SPTB and ANK1 are the most frequently mutated genes in Chinese HS patients. Among 34 mutations identified, 21 were novel. Most of SPTB and ANK1 mutations were nonsense (8/16) and frameshift (6/16) mutations. By trio analysis of eight families we have confirmed six de novo mutations. In addition, genotype-phenotype analysis was also performed by comparing clinical manifestations among three groups of patients with SPTB, ANK1, and SLC4A1 mutations. It revealed that patients with ANK1 mutations had a significantly higher level of MCV and MCH but lower percentage of spherocytes compared with those carrying SPTB mutations. In conclusion, our results suggested that molecular diagnosis by next-generation sequencing (NGS) is a fast, economic, and accurate way to detect and identify pathogenic alterations of inherited diseases, highlighting the potential usage of NGS in clinical practice.
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Affiliation(s)
- Li Qin
- Department of Pathology and Lab Medicine, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences, Tianjin, PR China.,Tianjin Sino-US Diagnostics Co., Ltd., Tianjin, PR China
| | - Yanbo Nie
- Tianjin Sino-US Diagnostics Co., Ltd., Tianjin, PR China
| | - Hong Zhang
- Tianjin Sino-US Diagnostics Co., Ltd., Tianjin, PR China
| | - Long Chen
- Tianjin Sino-US Diagnostics Co., Ltd., Tianjin, PR China
| | - Donglei Zhang
- Department of Pathology and Lab Medicine, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences, Tianjin, PR China.,Tianjin Sino-US Diagnostics Co., Ltd., Tianjin, PR China
| | - Yani Lin
- Department of Pathology and Lab Medicine, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences, Tianjin, PR China.,Tianjin Sino-US Diagnostics Co., Ltd., Tianjin, PR China
| | - Kun Ru
- Department of Pathology and Lab Medicine, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences, Tianjin, PR China. .,Tianjin Sino-US Diagnostics Co., Ltd., Tianjin, PR China.
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Becker HM. Carbonic anhydrase IX and acid transport in cancer. Br J Cancer 2020; 122:157-167. [PMID: 31819195 PMCID: PMC7051959 DOI: 10.1038/s41416-019-0642-z] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/29/2019] [Accepted: 10/22/2019] [Indexed: 02/07/2023] Open
Abstract
Alterations in tumour metabolism and acid/base regulation result in the formation of a hostile environment, which fosters tumour growth and metastasis. Acid/base homoeostasis in cancer cells is governed by the concerted interplay between carbonic anhydrases (CAs) and various transport proteins, which either mediate proton extrusion or the shuttling of acid/base equivalents, such as bicarbonate and lactate, across the cell membrane. Accumulating evidence suggests that some of these transporters interact both directly and functionally with CAIX to form a protein complex coined the 'transport metabolon'. Transport metabolons formed between bicarbonate transporters and CAIX require CA catalytic activity and have a function in cancer cell migration and invasion. Another type of transport metabolon is formed by CAIX and monocarboxylate transporters. In this complex, CAIX functions as a proton antenna for the transporter, which drives the export of lactate and protons from the cell. Since CAIX is almost exclusively expressed in cancer cells, these transport metabolons might serve as promising targets to interfere with tumour pH regulation and energy metabolism. This review provides an overview of the current state of research on the function of CAIX in tumour acid/base transport and discusses how CAIX transport metabolons could be exploited in modern cancer therapy.
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Affiliation(s)
- Holger M Becker
- Institute of Physiological Chemistry, University of Veterinary Medicine Hannover, D-30559, Hannover, Germany.
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Remigante A, Morabito R, Marino A. Natural Antioxidants Beneficial Effects on Anion Exchange through Band 3 Protein in Human Erythrocytes. Antioxidants (Basel) 2019; 9:antiox9010025. [PMID: 31888111 PMCID: PMC7022719 DOI: 10.3390/antiox9010025] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 12/23/2019] [Accepted: 12/24/2019] [Indexed: 01/06/2023] Open
Abstract
Band 3 protein (B3p) exchanging Cl− and HCO3− through erythrocyte membranes is responsible for acid balance, ion distribution and gas exchange, thus accounting for homeostasis of both erythrocytes and entire organisms. Moreover, since B3p cross links with the cytoskeleton and the proteins underlying the erythrocyte membrane, its function also impacts cell shape and deformability, essential to adaptation of erythrocyte size to capillaries for pulmonary circulation. As growing attention has been directed toward this protein in recent years, the present review was conceived to report the most recent knowledge regarding B3p, with specific regard to its anion exchange capability under in vitro oxidative conditions. Most importantly, the role of natural antioxidants, i.e., curcumin, melatonin and Mg2+, in preventing detrimental oxidant effects on B3p is considered.
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Farsaci F, Tellone E, Russo A, Galtieri A, Ficarra S. Thermodynamic characterization of RBCs highlights correlations between different hemoglobin types and Band 3 interactions. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.112070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Sun S, Zhang D, Sun G, Song Y, Cai J, Fan Z, Wang H. Solute carrier family 4 member 1 might participate in the pathogenesis of Meniere's disease in a murine endolymphatic hydrop model. Acta Otolaryngol 2019; 139:966-976. [PMID: 31536436 DOI: 10.1080/00016489.2019.1663365] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Background: To date, the pathogenesis of Meniere's disease (MD) remains unclear. Previous research found that the SLC4A1 gene significantly down-regulated. Aims: This study sought to understand the effect of SLC4A1 on the pathogenesis of MD. ELH C57 mice models were induced by intraperitoneal injection of AVP. Material and methods: The mRNA expression levels of SLC4A1, SLC4A10 and SLC26A4 were monitored by real-time quantitative PCR, the protein expression levels of SLC4A1 were monitored by immunoblotting and immunofluorescence before and after the ELH. DIDS is an inhibitor of SLC4A1. The expression levels of SLC4A1 were also monitored in the AVP + DIDS group. Results: We successfully established the model of ELH after applied AVP. The results of HE staining showed displacement of Reissner's membrane with bulge to scala vestibule in ears of the AVP group. Cochlea/ELS SLC4A1 protein and SLC4A1, SLC4A10, SLC26A4 mRNA expressions were reduced significantly in C57 mice of the AVP group. The SLC4A1 protein expression levels and SLC4A1, SLC4A10, SLC26A4 mRNA expression levels declined more obvious in the cochlea and ELS in C57 mice of the AVP + DIDS group. Conclusions and significance: SLC4A1 was a protective factor in the pathogenesis of MD, but the mechanisms were unknown.
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Affiliation(s)
- Shujuan Sun
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital Affiliated to Shandong University, Jinan 250022, P.R. China
| | - Daogong Zhang
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital Affiliated to Shandong University, Jinan 250022, P.R. China
| | - Gaoying Sun
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital Affiliated to Shandong University, Jinan 250022, P.R. China
| | - Yongdong Song
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital Affiliated to Shandong University, Jinan 250022, P.R. China
| | - Jing Cai
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital Affiliated to Shandong University, Jinan 250022, P.R. China
| | - Zhaomin Fan
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital Affiliated to Shandong University, Jinan 250022, P.R. China
| | - Haibo Wang
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital Affiliated to Shandong University, Jinan 250022, P.R. China
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Absolute proteome quantification of highly purified populations of circulating reticulocytes and mature erythrocytes. Blood Adv 2019; 2:2646-2657. [PMID: 30327373 DOI: 10.1182/bloodadvances.2018023515] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 09/10/2018] [Indexed: 12/20/2022] Open
Abstract
Reticulocytes produced in the bone marrow undergo maturation in the bloodstream to give rise to erythrocytes. Although the proteome of circulating red cells has been the subject of several reports, the cellular populations used for these studies were never completely devoid of reticulocytes. In our current study, we used highly purified erythrocyte and reticulocyte populations to quantify the absolute expression levels of the proteins in each cell population. Erythrocytes and reticulocytes were purified in a multistep process involving cellulose chromatography, Percoll gradient centrifugation, and fluorescence cell sorting after thiazole orange labeling. Proteins were analyzed by mass spectrometry from whole cells and erythrocyte plasma membrane (ghosts), leading to the identification and quantification of 2077 proteins, including 654 that were reticulocyte-specific. Absolute quantifications of these proteins were made using the mean corpuscular hemoglobin content of the cells as a standard. For each protein, we calculated the percentage loss during the terminal stages of reticulocyte maturation and the percentage of association with the plasma membrane. In addition, we used modified adenosine triphosphate and adenosine diphosphate molecules that enable the transfer of a biotin molecule to the catalytic sites of kinases to isolate active kinases in the erythrocytes and determined the absolute expression of 75 protein kinases and the modification of their expression during reticulocyte maturation. Our findings represent the first absolute quantification of proteins that are specifically expressed in normal erythrocytes with no detectable contamination by reticulocytes. Our findings thus represent a reference database for the future proteomic analysis of pathological erythrocytes.
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De Vecchis D, Reithmeier RAF, Kalli AC. Molecular Simulations of Intact Anion Exchanger 1 Reveal Specific Domain and Lipid Interactions. Biophys J 2019; 117:1364-1379. [PMID: 31540709 PMCID: PMC6818359 DOI: 10.1016/j.bpj.2019.08.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 07/30/2019] [Accepted: 08/22/2019] [Indexed: 12/23/2022] Open
Abstract
Anion exchanger 1 (AE1) is responsible for the exchange of bicarbonate and chloride across the erythrocyte plasma membrane. Human AE1 consists of a cytoplasmic and a membrane domain joined by a 33-residue flexible linker. Crystal structures of the individual domains have been determined, but the intact AE1 structure remains elusive. In this study, we use molecular dynamics simulations and modeling to build intact AE1 structures in a complex lipid bilayer that resembles the native erythrocyte plasma membrane. AE1 models were evaluated using available experimental data to provide an atomistic view of the interaction and dynamics of the cytoplasmic domain, the membrane domain, and the connecting linker in a complete model of AE1 in a lipid bilayer. Anionic lipids were found to interact strongly with AE1 at specific amino acid residues that are linked to diseases and blood group antigens. Cholesterol was found in the dimeric interface of AE1, suggesting that it may regulate subunit interactions and anion transport.
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Affiliation(s)
- Dario De Vecchis
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| | | | - Antreas C Kalli
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom; Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom.
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Feng HZ, Jin JP. Transgenic expression of carbonic anhydrase III in cardiac muscle demonstrates a mechanism to tolerate acidosis. Am J Physiol Cell Physiol 2019; 317:C922-C931. [PMID: 31390226 DOI: 10.1152/ajpcell.00130.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Carbonic anhydrase III (CAIII) is abundant in liver, adipocytes, and skeletal muscles, but not heart. A cytosolic enzyme that catalyzes conversions between CO2 and HCO3- in the regulation of intracellular pH, its physiological role in myocytes is not fully understood. Mouse skeletal muscles lacking CAIII showed lower intracellular pH during fatigue, suggesting its function in stress tolerance. We created transgenic mice expressing CAIII in cardiomyocytes that lack endogenous CAIII. The transgenic mice showed normal cardiac development and life span under nonstress conditions. Studies of ex vivo working hearts under normal and acidotic conditions demonstrated that the transgenic and wild-type mouse hearts had similar pumping functions under normal pH. At acidotic pH, however, CAIII transgenic mouse hearts showed significantly less decrease in cardiac function than that of wild-type control as shown by higher ventricular pressure development, systolic and diastolic velocities, and stroke volume via elongating the time of diastolic ejection. In addition to the effect of introducing CAIII into cardiomyocytes on maintaining homeostasis to counter acidotic stress, the results demonstrate the role of carbonic anhydrases in maintaining intracellular pH in muscle cells as a potential mechanism to treat heart failure.
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Affiliation(s)
- Han-Zhong Feng
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - J-P Jin
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
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50
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Red cell membrane proteins. Hemasphere 2019; 3:HemaSphere-2019-0029. [PMID: 35309774 PMCID: PMC8925656 DOI: 10.1097/hs9.0000000000000189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 02/12/2019] [Indexed: 11/29/2022] Open
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