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Sudnitsyna J, Ruzhnikova TO, Panteleev MA, Kharazova A, Gambaryan S, Mindukshev IV. Chloride Gradient Is Involved in Ammonium Influx in Human Erythrocytes. Int J Mol Sci 2024; 25:7390. [PMID: 39000500 PMCID: PMC11242273 DOI: 10.3390/ijms25137390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 06/20/2024] [Accepted: 06/29/2024] [Indexed: 07/16/2024] Open
Abstract
The ammonia/ammonium (NH3/NH4+, AM) concentration in human erythrocytes (RBCs) is significantly higher than in plasma. Two main possible mechanisms for AM transport, including simple and facilitated diffusion, are described; however, the driving force for AM transport is not yet fully characterized. Since the erythroid ammonium channel RhAG forms a structural unit with anion exchanger 1 (eAE1) within the ankyrin core complex, we hypothesized the involvement of eAE1 in AM transport. To evaluate the functional interaction between eAE1 and RhAG, we used a unique feature of RBCs to swell and lyse in isotonic NH4+ buffer. The kinetics of cell swelling and lysis were analyzed by flow cytometry and an original laser diffraction method, adapted for accurate volume sensing. The eAE1 role was revealed according to (i) the changes in cell swelling and lysis kinetics, and (ii) changes in intracellular pH, triggered by eAE1 inhibition or the modulation of eAE1 main ligand concentrations (Cl- and HCO3-). Additionally, the AM import kinetics was analyzed enzymatically and colorimetrically. In NH4+ buffer, RBCs concentration-dependently swelled and lysed when [NH4+] exceeded 100 mM. Cell swelling and hemolysis were tightly regulated by chloride concentration. The complete substitution of chloride with glutamate prevented NH4+-induced cell swelling and hemolysis, and the restoration of [Cl-] dose-dependently amplified the rates of RBC swelling and lysis and the percentage of hemolyzed cells. Similarly, eAE1 inhibition impeded cell swelling and completely prevented hemolysis. Accordingly, eAE1 inhibition, or a lack of chloride anions in the buffer, significantly decreased NH4+ import. Our data indicate that the eAE1-mediated chloride gradient is required for AM transport. Taken together, our data reveal a new player in AM transport in RBCs.
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Affiliation(s)
- Julia Sudnitsyna
- Center for Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, 30 Srednyaya Kalitnikovskaya St., 109029 Moscow, Russia
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 44 Thorez Ave., 194223 Saint Petersburg, Russia
| | - Tamara O Ruzhnikova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 44 Thorez Ave., 194223 Saint Petersburg, Russia
- Department of Cytology and Histology, Saint Petersburg State University, 7/9 Universitetskaya Emb., 199034 Saint Petersburg, Russia
| | - Mikhail A Panteleev
- Center for Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, 30 Srednyaya Kalitnikovskaya St., 109029 Moscow, Russia
| | - Alexandra Kharazova
- Department of Cytology and Histology, Saint Petersburg State University, 7/9 Universitetskaya Emb., 199034 Saint Petersburg, Russia
| | - Stepan Gambaryan
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 44 Thorez Ave., 194223 Saint Petersburg, Russia
| | - Igor V Mindukshev
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 44 Thorez Ave., 194223 Saint Petersburg, Russia
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Johnsen LØ, Friis KA, Møller-Madsen MK, Damkier HH. Mechanisms of cerebrospinal fluid secretion by the choroid plexus epithelium: Application to various intracranial pathologies. Clin Anat 2024. [PMID: 38894645 DOI: 10.1002/ca.24199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 06/02/2024] [Accepted: 06/06/2024] [Indexed: 06/21/2024]
Abstract
The choroid plexus (CP) is a small yet highly active epithelial tissue located in the ventricles of the brain. It secretes most of the CSF that envelops the brain and spinal cord. The epithelial cells of the CP have a high fluid secretion rate and differ from many other secretory epithelia in the organization of several key ion transporters. One striking difference is the luminal location of, for example, the vital Na+-K+-ATPase. In recent years, there has been a renewed focus on the role of ion transporters in CP secretion. Several studies have indicated that increased membrane transport activity is implicated in disorders such as hydrocephalus, idiopathic intracranial hypertension, and posthemorrhagic sequelae. The importance of the CP membrane transporters in regulating the composition of the CSF has also been a focus in research in recent years, particularly as a regulator of breathing and hemodynamic parameters such as blood pressure. This review focuses on the role of the fundamental ion transporters involved in CSF secretion and its ion composition. It gives a brief overview of the established factors and controversies concerning ion transporters, and finally discusses future perspectives related to the role of these transporters in the CP epithelium.
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Zhao JZ, Ge YY, Xue LF, Xu YX, Yue J, Li C, Xiao WL. CA1 Modulates the Osteogenic Differentiation of Dental Follicle Stem Cells by Activating the BMP Signaling Pathway In Vitro. Tissue Eng Regen Med 2024:10.1007/s13770-024-00642-4. [PMID: 38652220 DOI: 10.1007/s13770-024-00642-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 03/09/2024] [Accepted: 03/21/2024] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND Carbonic anhydrase 1 (CA1) has been found to be involved in osteogenesis and osteoclast in various human diseases, but the molecular mechanisms are not completely understood. In this study, we aim to use siRNA and lentivirus to reduce or increase the expression of CA1 in Dental follicle stem cells (DFSCs), in order to further elucidate the role and mechanism of CA1 in osteogenesis, and provide better osteogenic growth factors and stem cell selection for the application of bone tissue engineering in alveolar bone fracture transplantation. METHODS The study used RNA interference and lentiviral vectors to manipulate the expression of the CA1 gene in DFSCs during in vitro osteogenic induction. The expression of osteogenic marker genes was evaluated and changes in CA1, alkaline phosphatase (ALP), Runt-related transcription factor 2 (RUNX2), and Bone morphogenetic proteins (BMP2) were measured using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting (WB). The osteogenic effect was assessed through Alizarin Red staining. RESULTS The mRNA and protein expression levels of CA1, ALP, RUNX2, and BMP2 decreased distinctly in the si-CA1 group than other groups (p < 0.05). In the Lentivirus-CA1 (LV-CA1) group, the mRNA and protein expressions of CA1, ALP, RUNX2, and BMP2 were amplified to varying degrees than other groups (p < 0.05). Apart from CA1, BMP2 (43.01%) and ALP (36.69%) showed significant upregulation (p < 0.05). Alizarin red staining indicated that the LV-CA1 group produced more calcified nodules than other groups, with a higher optical density (p < 0.05), and the osteogenic effect was superior. CONCLUSIONS CA1 can impact osteogenic differentiation via BMP related signaling pathways, positioning itself upstream in osteogenic signaling pathways, and closely linked to osteoblast calcification and ossification processes.
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Affiliation(s)
- Jin-Ze Zhao
- Department of Oral and Maxillofacial Surgery, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China
- School of Stomatology, Qingdao University, Qingdao, 266023, China
| | - Ying-Ying Ge
- Department of Oral and Maxillofacial Surgery, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China
- School of Stomatology, Qingdao University, Qingdao, 266023, China
| | - Ling-Fa Xue
- Department of Oral and Maxillofacial Surgery, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China
- School of Stomatology, Qingdao University, Qingdao, 266023, China
| | - Yao-Xiang Xu
- Department of Oral and Maxillofacial Surgery, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China
- School of Stomatology, Qingdao University, Qingdao, 266023, China
| | - Jin Yue
- Department of Oral and Maxillofacial Surgery, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China
- School of Stomatology, Qingdao University, Qingdao, 266023, China
| | - Cong Li
- Department of Oral and Maxillofacial Surgery, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China
- School of Stomatology, Qingdao University, Qingdao, 266023, China
| | - Wen-Lin Xiao
- Department of Oral and Maxillofacial Surgery, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China.
- School of Stomatology, Qingdao University, Qingdao, 266023, China.
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Chatzinikolaou PN, Margaritelis NV, Paschalis V, Theodorou AA, Vrabas IS, Kyparos A, D'Alessandro A, Nikolaidis MG. Erythrocyte metabolism. Acta Physiol (Oxf) 2024; 240:e14081. [PMID: 38270467 DOI: 10.1111/apha.14081] [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: 07/03/2023] [Revised: 12/11/2023] [Accepted: 01/01/2024] [Indexed: 01/26/2024]
Abstract
Our aim is to present an updated overview of the erythrocyte metabolism highlighting its richness and complexity. We have manually collected and connected the available biochemical pathways and integrated them into a functional metabolic map. The focus of this map is on the main biochemical pathways consisting of glycolysis, the pentose phosphate pathway, redox metabolism, oxygen metabolism, purine/nucleoside metabolism, and membrane transport. Other recently emerging pathways are also curated, like the methionine salvage pathway, the glyoxalase system, carnitine metabolism, and the lands cycle, as well as remnants of the carboxylic acid metabolism. An additional goal of this review is to present the dynamics of erythrocyte metabolism, providing key numbers used to perform basic quantitative analyses. By synthesizing experimental and computational data, we conclude that glycolysis, pentose phosphate pathway, and redox metabolism are the foundations of erythrocyte metabolism. Additionally, the erythrocyte can sense oxygen levels and oxidative stress adjusting its mechanics, metabolism, and function. In conclusion, fine-tuning of erythrocyte metabolism controls one of the most important biological processes, that is, oxygen loading, transport, and delivery.
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Affiliation(s)
- Panagiotis N Chatzinikolaou
- Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
| | - Nikos V Margaritelis
- Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
| | - Vassilis Paschalis
- School of Physical Education and Sport Science, National and Kapodistrian University of Athens, Athens, Greece
| | - Anastasios A Theodorou
- Department of Life Sciences, School of Sciences, European University Cyprus, Nicosia, Cyprus
| | - Ioannis S Vrabas
- Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
| | - Antonios Kyparos
- Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
| | - Angelo D'Alessandro
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Michalis G Nikolaidis
- Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
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Aydin BO, Anil DA, Demir Y, Alagoz MA. Organohalogen chalcones: design, synthesis, ADMET prediction, molecular dynamics study and inhibition effect on acetylcholinesterase and carbonic anhydrase. Mol Divers 2024:10.1007/s11030-023-10774-9. [PMID: 38170420 DOI: 10.1007/s11030-023-10774-9] [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: 08/13/2023] [Accepted: 11/17/2023] [Indexed: 01/05/2024]
Abstract
In an effort to discover potential acetylcholinesterase (AChE) and carbonic anhydrase (CA) inhibitors, a novel series of organohalogen chalcone derivatives (12-20, 23-30) was synthesized, and their chemical structures were characterized by spectral analysis. They showed a highly potent inhibition effect on AChE and hCAs (Ki values range from 5.07 ± 0.062 to 65.53 ± 4.36 nM for AChE, 13.54 ± 2.55 to 94.11 ± 10.39 nM for hCA I, and 5.21 ± 0.54 to 57.44 ± 3.12 nM for hCA II). In addition, the chalcone derivatives with the highest inhibitor score docked into the active site of the indicated metabolic enzyme receptors, and their absorption, metabolism, and toxic properties were evaluated according to ADMET's estimation.Compounds 16 and 19 exhibited the highest inhibition score, emerged as lead compounds, and inspired the development of more potent compounds.
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Affiliation(s)
- Busra Ozturk Aydin
- Department of Chemistry, Faculty of Science, Ataturk University, 25240, Erzurum, Turkey
| | - Derya Aktas Anil
- Department of Chemistry, Faculty of Science, Ataturk University, 25240, Erzurum, Turkey.
- Department of Chemistry and Chemical Process Technologies, Technical Sciences Vocational School, Ataturk University, 25240, Erzurum, Turkey.
| | - Yeliz Demir
- Department of Pharmacy Services, Nihat Delibalta Göle Vocational School, Ardahan University, 75002, Ardahan, Turkey
| | - Mehmet Abdullah Alagoz
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Inonu University, Malatya, Turkey
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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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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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Leng Y, Zhou H, Wang W, Fu J. Diagnostic role of urinary CA-2 in urinary stones and its prediction of complications. Am J Transl Res 2022; 14:8686-8694. [PMID: 36628213 PMCID: PMC9827313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 11/21/2022] [Indexed: 01/12/2023]
Abstract
BACKGROUND Carbonic anhydrase-2 (CA-2) is involved in the mineralization and calcification of organisms. Evidence suggests that CA-2 is associated with urolithiasis. However, the relationship between CA-2 and urinary stones remains unclear. The study aimed to assess the correlation of urinary CA-2 (uCA-2) level with the risk of urinary stones. METHODS A retrospective cohort study was conducted on patients with urinary stones and healthy subjects who presented to our hospital between March 2017 and November 2019 to determine the pretreatment uCA-2 level by enzyme linked immunosorbent assay (ELISA). Differences in uCA-2 levels between patients with urinary stones and healthy subjects were compared. Then, comparison between stone patients with complications and those without was carried out as well as correlation analysis to detect factors associated with biomarker expression. RESULTS Patients with urinary stones (n=118) were designated the urinary stones group and healthy subjects (n=42) were designated the healthy control group. The mean pretreatment uCA-2 level was significantly higher in cases than in controls (P=0.028). Furthermore, the uCA-2 level had a positive correlation with urinary stone-associated complications (R=0.379, P<0.001), especially pain (R=0.524, P<0.001) and hematuria (R=0.374, P<0.001). Receiver operating characteristic curve (ROC) analysis revealed that a uCA-2 level threshold of 10.94 ng/mL had 83.67% sensitivity and 68.12% specificity for predicting complications in patients with urinary stones. CONCLUSION Excessive uCA-2 excretion is a major risk factor for urinary stones. Our findings suggest that uCA-2 may be used as a novel biomarker for the diagnosis of urinary stones and the prediction of its complications.
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Affiliation(s)
- Yuanjing Leng
- Department of Urology, Affiliated Hospital of Jiujiang CollegeJiujiang 332000, Jiangxi, People’s Republic of China
| | - Haibin Zhou
- Department of Urology, Affiliated Hospital of Jiujiang CollegeJiujiang 332000, Jiangxi, People’s Republic of China
| | - Wenjuan Wang
- Department of Clinical Laboratory, Affiliated Hospital of Jiujiang CollegeJiujiang 332000, Jiangxi, People’s Republic of China
| | - Jiangling Fu
- Clinical Precision Medical Research Center, Affiliated Hospital of Jiujiang CollegeJiujiang 332000, Jiangxi, People’s Republic of China
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10
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Dotsenko OI. The whole-cell kinetic metabolic model of the pH regulation mechanisms in human erythrocytes. REGULATORY MECHANISMS IN BIOSYSTEMS 2022. [DOI: 10.15421/022235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Mathematical modeling in recent years helped to obtain answers to questions that were difficult or even impossible to answer experimentally, to predict several unexpected connections in cell metabolism and to understand and importance of certain biochemical reactions. Due to the complexity and variety of processes underlying the mechanisms of intracellular pH (pHi) regulation, mathematical modeling and metabolome analysis are powerful tools for their analysis. In this regard, a mathematical metabolic model for human erythrocytes was created, which combines cellular metabolism with acid-base processes and gas exchange. The model consists of the main metabolic pathways, such as glycolysis, the pentose phosphate pathway, some membrane transport systems, and interactions between hemoglobin and metabolites. The Jacobs-Stewart cycle, which is fundamental in gas exchange and pH regulation, was included to these pathways. The model was created in the COPASI environment, consisted of 85 reactions, the rate of which is based on accurate kinetic equations. The time dependences of reaction flows and metabolite concentrations, as an outcome of calculations, allowed us to reproduce the behaviour of the metabolic system after its disturbance in vitro and to establish the recovery mechanisms or approximation to stationary states. The COPASI simulation environment provides model flexibility by reproducing any experimental design by optimizing direct quantitative comparisons between measured and predicted results. Thus, the procedure of parameters optimization (Parameter Estimation) followed by the solution of the model’s differential equations (Time Course procedure) was used to predict the behaviour of all measured and unmeasured variables over time. The initial intracellular concentrations of CO2, HCO3– in human erythrocytes used for incubation in a phosphate buffer medium were calculated. Changes in CO2, HCO3– content over time were shown. It was established that the regulation of pH in erythrocytes placed in a buffer medium takes place with the participation of two types of processes – fast (takes place in 1.3 s) and slow. It is shown that fast processes are aimed at restoring the intracellular balance between CO2 and HCO3–, slow processes are aimed at establishing the balance of H+ between the cell and the extracellular environment. The role of carbonic anhydrase (CA) and hemoglobin in the processes of pH stabilization is shown and analyzed. The physiological role of the metabolon between band 3 protein (AE1), CA, aquaporin and hemoglobin in maintaining pH homeostasis in the conditions of in vitro experiments are discussed.
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Fang Y, Huang L, Wang X, Si X, Lenahan C, Shi H, Shao A, Tang J, Chen S, Zhang J, Zhang JH. A new perspective on cerebrospinal fluid dynamics after subarachnoid hemorrhage: From normal physiology to pathophysiological changes. J Cereb Blood Flow Metab 2022; 42:543-558. [PMID: 34806932 PMCID: PMC9051143 DOI: 10.1177/0271678x211045748] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Knowledge about the dynamic metabolism and function of cerebrospinal fluid (CSF) physiology has rapidly progressed in recent decades. It has traditionally been suggested that CSF is produced by the choroid plexus and drains to the arachnoid villi. However, recent findings have revealed that the brain parenchyma produces a large portion of CSF and drains through the perivascular glymphatic system and meningeal lymphatic vessels into the blood. The primary function of CSF is not limited to maintaining physiological CNS homeostasis but also participates in clearing waste products resulting from neurodegenerative diseases and acute brain injury. Aneurysmal subarachnoid hemorrhage (SAH), a disastrous subtype of acute brain injury, is associated with high mortality and morbidity. Post-SAH complications contribute to the poor outcomes associated with SAH. Recently, abnormal CSF flow was suggested to play an essential role in the post-SAH pathophysiological changes, such as increased intracerebral pressure, brain edema formation, hydrocephalus, and delayed blood clearance. An in-depth understanding of CSF dynamics in post-SAH events would shed light on potential development of SAH treatment options. This review summarizes and updates the latest physiological characteristics of CSF dynamics and discusses potential pathophysiological changes and therapeutic targets after SAH.
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Affiliation(s)
- Yuanjian Fang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Lei Huang
- Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA.,Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, CA, USA
| | - Xiaoyu Wang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiaoli Si
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Cameron Lenahan
- Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA.,Burrell College of Osteopathic Medicine, Las Cruces, NM, USA
| | - Hui Shi
- Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA.,Department of Neurosurgery, Yongchuan Hospital, Chongqing Medical University, Chongqing, China
| | - Anwen Shao
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jiping Tang
- Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA.,Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, CA, USA.,Department of Anesthesiology, Loma Linda University, Loma Linda, CA, USA
| | - Sheng Chen
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jianmin Zhang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - John H Zhang
- Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA.,Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, CA, USA.,Department of Anesthesiology, Loma Linda University, Loma Linda, CA, USA
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12
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Choi I, Yang H, Kim E, Lee S. Bicarbonate-Independent Sodium Conductance of Na/HCO3 Cotransporter NBCn1 Decreases NMDA Receptor Function. Curr Issues Mol Biol 2022; 44:1284-1293. [PMID: 35723309 PMCID: PMC8947554 DOI: 10.3390/cimb44030086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/10/2022] [Accepted: 03/11/2022] [Indexed: 12/18/2022] Open
Abstract
The sodium bicarbonate cotransporter NBCn1 is an electroneutral transporter with a channel activity that conducts Na+ in a HCO3–-independent manner. This channel activity was suggested to functionally affect other membrane proteins which permeate Na+ influx. We previously reported that NBCn1 is associated with the NMDA receptors (NMDARs) at the molecular and physiological levels. In this study, we examined whether NBCn1 channel activity affects NMDAR currents and whether this effect involves the interaction between the two proteins. NBCn1 and the NMDAR subunits GluN1A/GluN2A were expressed in Xenopus oocytes, and glutamate currents produced by the receptors were measured using two-electrode voltage clamp. In the absence of CO2/HCO3–, NBCn1 channel activity decreased glutamate currents mediated by GluN1A/GluN2A. NBCn1 also decreased the slope of the current–voltage relationships for the glutamate current. Similar effects on the glutamate current were observed with and without PSD95, which can cluster NBCn1 and NMDARs. The channel activity was also observed in the presence of CO2/HCO3–. We conclude that NBCn1 channel activity decreases NMDAR function. Given that NBCn1 knockout mice develop a downregulation of NMDARs, our results are unexpected and suggest that NBCn1 has dual effects on NMDARs. It stabilizes NMDAR expression but decreases receptor function by its Na+ channel activity. The dual effects may play an important role in fine-tuning the regulation of NMDARs in the brain.
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13
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Zhou Z, Qian J, Kini A, Riederer B, Römermann D, Gros G, Seidler U. Loss of luminal carbonic anhydrase XIV results in decreased biliary bicarbonate output, liver fibrosis, and cholangiocyte proliferation in mice. Pflugers Arch 2022; 474:529-539. [PMID: 35119514 PMCID: PMC8993780 DOI: 10.1007/s00424-021-02659-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 12/22/2021] [Accepted: 12/23/2021] [Indexed: 12/12/2022]
Abstract
Carbonic anhydrase XIV (Car14) is highly expressed in the hepatocyte, with predominance in the canalicular membrane and its active site in the extracellular milieu. The aim of this study is to determine the physiological relevance of Car14 for biliary fluid and acid/base output, as well as its role in the maintenance of hepatocellular and cholangiocyte integrity. The common bile duct of anesthetized car14-/- and car14+/+ mice was cannulated and hepatic HCO3- output was measured by microtitration and bile flow gravimetrically before and during stimulation with intravenously applied tauroursodeoxycholic acid (TUDCA). Morphological alterations and hepatic damage were assessed histologically and immunohistochemically in liver tissue from 3- to 52-week-old car14-/- and car14+/+ mice, and gene and/or protein expression was measured for pro-inflammatory cytokines, fibrosis, and cholangiocyte markers. Biliary basal and more so TUDCA-stimulated HCO3- output were significantly reduced in car14-/- mice of all age groups, whereas bile flow and hepatic and ductular morphology were normal at young age. Car14-/- mice developed fibrotic and proliferative changes in the small bile ducts at advanced age, which was accompanied by a reduction in bile flow, and an upregulation of hepatic cytokeratin 19 mRNA and protein expression. Membrane-bound Car14 is essential for biliary HCO3- output, and its loss results in gradual development of small bile duct disease and hepatic fibrosis. Bile flow is not compromised in young adulthood, suggesting that Car14-deficient mice may be a model to study the protective role of biliary canalicular HCO3- against luminal noxi to the cholangiocyte.
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Affiliation(s)
- Zhenzhen Zhou
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jiajie Qian
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany
- Department of Gastrointestinal Surgery, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Archana Kini
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany
| | - Brigitte Riederer
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany
| | - Dorothee Römermann
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany
| | - Gerolf Gros
- Department of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Ursula Seidler
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany.
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Carl Neuberg Straße 1, 30625, Hannover, Germany.
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14
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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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15
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Nocentini A, Supuran CT, Capasso C. An overview on the recently discovered iota-carbonic anhydrases. J Enzyme Inhib Med Chem 2021; 36:1988-1995. [PMID: 34482770 PMCID: PMC8425729 DOI: 10.1080/14756366.2021.1972995] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Carbonic anhydrases (CAs, EC 4.2.1.1) have been studied for decades and have been classified as a superfamily of enzymes which includes, up to date, eight gene families or classes indicated with the Greek letters α, β, γ, δ, ζ, η, θ, ι. This versatile enzyme superfamily is involved in multiple physiological processes, catalysing a fundamental reaction for all living organisms, the reversible hydration of carbon dioxide to bicarbonate and a proton. Recently, the ι-CA (LCIP63) from the diatom Thalassiosira pseudonana and a bacterial ι-CA (BteCAι) identified in the genome of Burkholderia territorii were characterised. The recombinant BteCAι was observed to act as an excellent catalyst for the physiologic reaction. Very recently, the discovery of a novel ι-CAs (COG4337) in the eukaryotic microalga Bigelowiella natans and the cyanobacterium Anabaena sp. PCC7120 has brought to light an unexpected feature for this ancient superfamily: this ι-CAs was catalytically active without a metal ion cofactor, unlike the previous reported ι-CAs as well as all known CAs investigated so far. This review reports recent investigations on ι-CAs obtained in these last three years, highlighting their peculiar features, and hypothesising that possibly this new CA family shows catalytic activity without the need of metal ions.
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Affiliation(s)
- Alessio Nocentini
- Department of NEUROFARBA, Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Firenze, Italy
| | - Claudiu T Supuran
- Department of NEUROFARBA, Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Firenze, Italy
| | - Clemente Capasso
- Department of Biology, Agriculture and Food Sciences, Institute of Biosciences and Bioresources, CNR, Napoli, Italy
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16
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Ion Channels, Transporters, and Sensors Interact with the Acidic Tumor Microenvironment to Modify Cancer Progression. Rev Physiol Biochem Pharmacol 2021; 182:39-84. [PMID: 34291319 DOI: 10.1007/112_2021_63] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Solid tumors, including breast carcinomas, are heterogeneous but typically characterized by elevated cellular turnover and metabolism, diffusion limitations based on the complex tumor architecture, and abnormal intra- and extracellular ion compositions particularly as regards acid-base equivalents. Carcinogenesis-related alterations in expression and function of ion channels and transporters, cellular energy levels, and organellar H+ sequestration further modify the acid-base composition within tumors and influence cancer cell functions, including cell proliferation, migration, and survival. Cancer cells defend their cytosolic pH and HCO3- concentrations better than normal cells when challenged with the marked deviations in extracellular H+, HCO3-, and lactate concentrations typical of the tumor microenvironment. Ionic gradients determine the driving forces for ion transporters and channels and influence the membrane potential. Cancer and stromal cells also sense abnormal ion concentrations via intra- and extracellular receptors that modify cancer progression and prognosis. With emphasis on breast cancer, the current review first addresses the altered ion composition and the changes in expression and functional activity of ion channels and transporters in solid cancer tissue. It then discusses how ion channels, transporters, and cellular sensors under influence of the acidic tumor microenvironment shape cancer development and progression and affect the potential of cancer therapies.
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17
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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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18
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De Luca V, Petreni A, Nocentini A, Scaloni A, Supuran CT, Capasso C. Effect of Sulfonamides and Their Structurally Related Derivatives on the Activity of ι-Carbonic Anhydrase from Burkholderia territorii. Int J Mol Sci 2021; 22:ijms22020571. [PMID: 33430028 PMCID: PMC7827628 DOI: 10.3390/ijms22020571] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 12/30/2020] [Accepted: 01/05/2021] [Indexed: 11/17/2022] Open
Abstract
Carbonic anhydrases (CAs) are essential metalloenzymes in nature, catalyzing the carbon dioxide reversible hydration into bicarbonate and proton. In humans, breathing and many other critical physiological processes depend on this enzymatic activity. The CA superfamily function and inhibition in pathogenic bacteria has recently been the object of significant advances, being demonstrated to affect microbial survival/virulence. Targeting bacterial CAs may thus be a valid alternative to expand the pharmacological arsenal against the emergence of widespread antibiotic resistance. Here, we report an extensive study on the inhibition profile of the recently discovered ι-CA class present in some bacteria, including Burkholderia territorii, namely BteCAι, using substituted benzene-sulfonamides and clinically licensed sulfonamide-, sulfamate- and sulfamide-type drugs. The BteCAι inhibition profile showed: (i) several benzene-sulfonamides with an inhibition constant lower than 100 nM; (ii) a different behavior with respect to other α, β and γ-CAs; (iii) clinically used drugs having a micromolar affinity. This prototype study contributes to the initial recognition of compounds which efficiently and selectively inhibit a bacterial member of the ι-CA class, for which such a selective inhibition with respect to other protein isoforms present in the host is highly desired and may contribute to the development of novel antimicrobials.
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Affiliation(s)
- Viviana De Luca
- Institute of Biosciences and Bioresources, CNR, via Pietro Castellino 111, 80131 Napoli, Italy;
- Proteomics & Mass Spectrometry Laboratory, ISPAAM, CNR, via Argine 1085, 80147 Napoli, Italy;
| | - Andrea Petreni
- Section of Pharmaceutical and Nutraceutical Sciences, Department of Neurofarba, University of Florence, via U. Schiff 6, 50019 Florence, Italy; (A.P.); (A.N.)
| | - Alessio Nocentini
- Section of Pharmaceutical and Nutraceutical Sciences, Department of Neurofarba, University of Florence, via U. Schiff 6, 50019 Florence, Italy; (A.P.); (A.N.)
| | - Andrea Scaloni
- Proteomics & Mass Spectrometry Laboratory, ISPAAM, CNR, via Argine 1085, 80147 Napoli, Italy;
| | - Claudiu T. Supuran
- Section of Pharmaceutical and Nutraceutical Sciences, Department of Neurofarba, University of Florence, via U. Schiff 6, 50019 Florence, Italy; (A.P.); (A.N.)
- Correspondence: (C.T.S.); (C.C.); Tel.: +39-055-4573729 (C.T.S.); +39-081-613-2559 (C.C.)
| | - Clemente Capasso
- Institute of Biosciences and Bioresources, CNR, via Pietro Castellino 111, 80131 Napoli, Italy;
- Correspondence: (C.T.S.); (C.C.); Tel.: +39-055-4573729 (C.T.S.); +39-081-613-2559 (C.C.)
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19
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Daane JM, Auvinet J, Stoebenau A, Yergeau D, Harris MP, Detrich HW. Developmental constraint shaped genome evolution and erythrocyte loss in Antarctic fishes following paleoclimate change. PLoS Genet 2020; 16:e1009173. [PMID: 33108368 PMCID: PMC7660546 DOI: 10.1371/journal.pgen.1009173] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 11/12/2020] [Accepted: 10/06/2020] [Indexed: 02/07/2023] Open
Abstract
In the frigid, oxygen-rich Southern Ocean (SO), Antarctic icefishes (Channichthyidae; Notothenioidei) evolved the ability to survive without producing erythrocytes and hemoglobin, the oxygen-transport system of virtually all vertebrates. Here, we integrate paleoclimate records with an extensive phylogenomic dataset of notothenioid fishes to understand the evolution of trait loss associated with climate change. In contrast to buoyancy adaptations in this clade, we find relaxed selection on the genetic regions controlling erythropoiesis evolved only after sustained cooling in the SO. This pattern is seen not only within icefishes but also occurred independently in other high-latitude notothenioids. We show that one species of the red-blooded dragonfish clade evolved a spherocytic anemia that phenocopies human patients with this disease via orthologous mutations. The genomic imprint of SO climate change is biased toward erythrocyte-associated conserved noncoding elements (CNEs) rather than to coding regions, which are largely preserved through pleiotropy. The drift in CNEs is specifically enriched near genes that are preferentially expressed late in erythropoiesis. Furthermore, we find that the hematopoietic marrow of icefish species retained proerythroblasts, which indicates that early erythroid development remains intact. Our results provide a framework for understanding the interactions between development and the genome in shaping the response of species to climate change. Our climate is rapidly changing. To better understand how species can adapt to major climate disturbance, we looked back into the past at a group of fishes that have encountered dramatic climate upheavals and thrived: Antarctic notothenioid fishes. In particular, we focus on the icefishes, which lost the ability to produce red blood cells in the frigid environment of the Southern Ocean. By integrating past climate records with a large genetic dataset of Antarctic fishes, we show that the loss of red blood cells occurred only after sustained cooling of the Southern Ocean. As cooling continued into the modern era, we discover that even some of the “red-blooded” relatives of the icefishes show early genetic and morphological signs of erythrocyte loss. This cooling event left a non-random imprint on the genome of icefishes. With few exceptions, the genetic toolkit underlying red cell development has remained intact in icefishes because many “erythroid” genes perform important functions in other tissues. Rather, mutations have accumulated in gene regulatory regions near genes that control terminal erythroid maturation, such that icefishes continue to produce red cell progenitors but not mature erythrocytes. These results show that the genetic constraints regulating embryonic development shaped the evolutionary response of this fish group to climate change.
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Affiliation(s)
- Jacob M. Daane
- Department of Marine and Environmental Sciences, Northeastern University Marine Science Center, Nahant, MA, United States of America
- Orthopaedic Research Laboratories, Department of Orthopaedic Surgery, Boston Children's Hospital, Boston, MA, United States of America
- Department of Genetics, Harvard Medical School, Boston, MA, United States of America
- * E-mail: (JMD); (HWD)
| | - Juliette Auvinet
- Department of Marine and Environmental Sciences, Northeastern University Marine Science Center, Nahant, MA, United States of America
| | - Alicia Stoebenau
- Department of Marine and Environmental Sciences, Northeastern University Marine Science Center, Nahant, MA, United States of America
| | - Donald Yergeau
- Department of Biology, Northeastern University, Boston, MA, United States of America
| | - Matthew P. Harris
- Orthopaedic Research Laboratories, Department of Orthopaedic Surgery, Boston Children's Hospital, Boston, MA, United States of America
- Department of Genetics, Harvard Medical School, Boston, MA, United States of America
| | - H. William Detrich
- Department of Marine and Environmental Sciences, Northeastern University Marine Science Center, Nahant, MA, United States of America
- Department of Biology, Northeastern University, Boston, MA, United States of America
- * E-mail: (JMD); (HWD)
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20
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Distinto S, Meleddu R, Ortuso F, Cottiglia F, Deplano S, Sequeira L, Melis C, Fois B, Angeli A, Capasso C, Angius R, Alcaro S, Supuran CT, Maccioni E. Exploring new structural features of the 4-[(3-methyl-4-aryl-2,3-dihydro-1,3-thiazol-2-ylidene)amino]benzenesulphonamide scaffold for the inhibition of human carbonic anhydrases. J Enzyme Inhib Med Chem 2019; 34:1526-1533. [PMID: 31431095 PMCID: PMC6713091 DOI: 10.1080/14756366.2019.1654470] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A library of 4-[(3-methyl-4-aryl-2,3-dihydro-1,3-thiazol-2-ylidene)amino]benzene-1-sulphonamides (EMAC8002a–m) was designed and synthesised to evaluate the effect of substituents in the positions 3 and 4 of the dihydrothiazole ring on the inhibitory potency and selectivity toward human carbonic anhydrase isoforms I, II, IX, and XII. Most of the new compounds preferentially inhibit the isoforms II and XII. Both electronic and steric features on the aryl substituent in the position 4 of the dihydrothiazole ring concur to determine the overall biological activity of these new derivatives.
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Affiliation(s)
- Simona Distinto
- Department of Life and Environmental Sciences, University of Cagliari , Cagliari , Italy
| | - Rita Meleddu
- Department of Life and Environmental Sciences, University of Cagliari , Cagliari , Italy
| | - Francesco Ortuso
- Dipartimento di Scienze della Salute, Università Magna Graecia di Catanzaro , Catanzaro , Italy
| | - Filippo Cottiglia
- Department of Life and Environmental Sciences, University of Cagliari , Cagliari , Italy
| | - Serenella Deplano
- Department of Life and Environmental Sciences, University of Cagliari , Cagliari , Italy
| | - Lisa Sequeira
- Department of Life and Environmental Sciences, University of Cagliari , Cagliari , Italy
| | - Claudia Melis
- Department of Life and Environmental Sciences, University of Cagliari , Cagliari , Italy
| | - Benedetta Fois
- Department of Life and Environmental Sciences, University of Cagliari , Cagliari , Italy
| | - Andrea Angeli
- Dipartimento NEUROFARBA, Sezione di Scienze Farmaceutiche, Università degli Studi di Firenze , Sesto Fiorentino , Italy
| | | | | | - Stefano Alcaro
- Dipartimento di Scienze della Salute, Università Magna Graecia di Catanzaro , Catanzaro , Italy
| | - Claudiu T Supuran
- Dipartimento NEUROFARBA, Sezione di Scienze Farmaceutiche, Università degli Studi di Firenze , Sesto Fiorentino , Italy
| | - Elias Maccioni
- Department of Life and Environmental Sciences, University of Cagliari , Cagliari , Italy
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21
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Jaquenod De Giusti C, Blanco PG, Lamas PA, Carrizo Velasquez F, Lofeudo JM, Portiansky EL, Alvarez BV. Carbonic anhydrase II/sodium-proton exchanger 1 metabolon complex in cardiomyopathy of ob -/- type 2 diabetic mice. J Mol Cell Cardiol 2019; 136:53-63. [PMID: 31518570 DOI: 10.1016/j.yjmcc.2019.09.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 07/17/2019] [Indexed: 10/26/2022]
Abstract
Heart failure is the leading cause of death among diabetic people. Cellular and molecular entities leading to diabetic cardiomyopathy are, however, poorly understood. Coupling of cardiac carbonic anhydrase II (CAII) and Na+/H+ exchanger 1 (NHE1) to form a transport metabolon was analyzed in obese type 2 diabetic mice (ob-/-) and control heterozygous littermates (ob+/-). Echocardiography showed elevated systolic interventricular septum thickness and systolic posterior wall thickness in ob-/- mice at 9 and 16 weeks. ob-/- mice showed increased left ventricular (LV) weight/tibia length ratio and increased cardiomyocyte cross sectional area as compared to controls, indicating cardiac hypertrophy. Immunoblot analysis showed increased CAII expression in LV samples of ob-/-vs. ob+/- mice, and augmented Ser703 phosphorylation on NHE1 in ob-/- hearts. Reciprocal co-immunoprecipitation analysis showed strong association of CAII and NHE1 in LV samples of ob-/- mice. NHE1-dependent rate of intracellular pH (pHi) normalization after transient acid loading of isolated cardiomyocytes was higher in ob-/- mice vs. ob+/-. NHE transport activity was also augmented in cultured H9C2 rat cardiomyoblasts treated with high glucose/high palmitate, and it was normalized after CA inhibition. We conclude that the NHE1/CAII metabolon complex is exacerbated in diabetic cardiomyopathy of ob-/- mice, which may lead to perturbation of pHi and [Na+] and [Ca2+] handling in these diseased hearts.
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Affiliation(s)
- Carolina Jaquenod De Giusti
- Centro de Investigaciones Cardiovasculares CIC-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Calle 60 y 120, 1900 La Plata, Argentina; Established Investigators of CONICET, Argentina
| | - Paula G Blanco
- Servicio de Cardiología, Facultad de Ciencias Veterinarias, UNLP, Argentina; Established Investigators of CONICET, Argentina
| | - Paula A Lamas
- Centro de Investigaciones Cardiovasculares CIC-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Calle 60 y 120, 1900 La Plata, Argentina
| | - Fernanda Carrizo Velasquez
- Centro de Investigaciones Cardiovasculares CIC-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Calle 60 y 120, 1900 La Plata, Argentina
| | - Juan M Lofeudo
- Centro de Investigaciones Cardiovasculares CIC-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Calle 60 y 120, 1900 La Plata, Argentina
| | - Enrique L Portiansky
- Laboratorio de Análisis de Imágenes, Facultad de Ciencias Veterinarias, UNLP, Argentina; Established Investigators of CONICET, Argentina
| | - Bernardo V Alvarez
- Centro de Investigaciones Cardiovasculares CIC-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Calle 60 y 120, 1900 La Plata, Argentina; Established Investigators of CONICET, Argentina.
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22
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Occhipinti R, Boron WF. Role of Carbonic Anhydrases and Inhibitors in Acid-Base Physiology: Insights from Mathematical Modeling. Int J Mol Sci 2019; 20:E3841. [PMID: 31390837 PMCID: PMC6695913 DOI: 10.3390/ijms20153841] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 07/24/2019] [Accepted: 07/25/2019] [Indexed: 01/25/2023] Open
Abstract
Carbonic anhydrases (CAs) catalyze a reaction fundamental for life: the bidirectional conversion of carbon dioxide (CO2) and water (H2O) into bicarbonate (HCO3-) and protons (H+). These enzymes impact numerous physiological processes that occur within and across the many compartments in the body. Within compartments, CAs promote rapid H+ buffering and thus the stability of pH-sensitive processes. Between compartments, CAs promote movements of H+, CO2, HCO3-, and related species. This traffic is central to respiration, digestion, and whole-body/cellular pH regulation. Here, we focus on the role of mathematical modeling in understanding how CA enhances buffering as well as gradients that drive fluxes of CO2 and other solutes (facilitated diffusion). We also examine urinary acid secretion and the carriage of CO2 by the respiratory system. We propose that the broad physiological impact of CAs stem from three fundamental actions: promoting H+ buffering, enhancing H+ exchange between buffer systems, and facilitating diffusion. Mathematical modeling can be a powerful tool for: (1) clarifying the complex interdependencies among reaction, diffusion, and protein-mediated components of physiological processes; (2) formulating hypotheses and making predictions to be tested in wet-lab experiments; and (3) inferring data that are impossible to measure.
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Affiliation(s)
- Rossana Occhipinti
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
| | - Walter F Boron
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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24
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Salvati KA, Beenhakker MP. Out of thin air: Hyperventilation-triggered seizures. Brain Res 2019; 1703:41-52. [PMID: 29288644 PMCID: PMC6546426 DOI: 10.1016/j.brainres.2017.12.037] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 11/29/2017] [Accepted: 12/27/2017] [Indexed: 12/11/2022]
Abstract
Voluntary hyperventilation triggers seizures in the vast majority of people with absence epilepsy. The mechanisms that underlie this phenomenon remain unknown. Herein, we review observations - many made long ago - that provide insight into the relationship between breathing and absence seizures.
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Affiliation(s)
- Kathryn A Salvati
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22903, United States
| | - Mark P Beenhakker
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22903, United States.
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25
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Giribabu N, Karim K, Salleh N. Effects of Marantodes pumilum (Kacip Fatimah) on vaginal pH and expression of vacoular ATPase and carbonic anhydrase in the vagina of sex-steroid deficient female rats. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2018; 49:95-105. [PMID: 30217266 DOI: 10.1016/j.phymed.2018.05.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 04/27/2018] [Accepted: 05/28/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND In sex-steroid deficiency, increased in the pH of vaginal fluid is due to low estrogen levels. HYPOTHESIS Consumption of Marantodes pumilum leaves helps to ameliorate increased in vaginal fluid pH in sex-steroid deficient condition. PURPOSE To investigate changes in vaginal fluid pH and expression of proteins that participate in pH changes i.e vacoular (V)-ATPases and carbonic anhydrases (CA) in the vagina following M. pumilum leaves consumption. METHODS Ovariectomized adult female rats were treated orally with M. pumilum leaves extract (MPE) at 100, 250 and 500 mg/kg.b.w and estradiol at 0.2 µg/kg/b.w for 28 days. At the end of the treatment, vaginal fluid pH was measured in anesthetised rats by using micropH probe. Following sacrificed, levels of V-ATPase and CA proteins and mRNAs in the vagina were identified by Western blotting and real-time PCR, respectively. Protein distribution was visualized by immunohistochemistry. RESULTS Administration of MPE causes the pH of vaginal fluid to decrease and expression and distribution of vaginal V-ATPase A & B and CA II, III, IX, XII and XIII to increase. CONCLUSIONS The decrease in vaginal fluid pH following MPE treatment suggested that this herb has potential to be used to ameliorate vaginal fluid pH changes in sex-steroid deficient condition.
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Affiliation(s)
- Nelli Giribabu
- Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Kamarulzaman Karim
- Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Naguib Salleh
- Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia.
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26
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Rasmussen JK, Boedtkjer E. Carbonic anhydrase inhibitors modify intracellular pH transients and contractions of rat middle cerebral arteries during CO 2/HCO 3- fluctuations. J Cereb Blood Flow Metab 2018; 38:492-505. [PMID: 28318362 PMCID: PMC5851140 DOI: 10.1177/0271678x17699224] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The CO2/HCO3- buffer minimizes pH changes in response to acid-base loads, HCO3- provides substrate for Na+,HCO3--cotransporters and Cl-/HCO3--exchangers, and H+ and HCO3- modify vasomotor responses during acid-base disturbances. We show here that rat middle cerebral arteries express cytosolic, mitochondrial, extracellular, and secreted carbonic anhydrase isoforms that catalyze equilibration of the CO2/HCO3- buffer. Switching from CO2/HCO3--free to CO2/HCO3--containing extracellular solution results in initial intracellular acidification due to hydration of CO2 followed by gradual alkalinization due to cellular HCO3- uptake. Carbonic anhydrase inhibition decelerates the initial acidification and attenuates the associated transient vasoconstriction without affecting intracellular pH or artery tone at steady-state. Na+,HCO3--cotransport and Na+/H+-exchange activity after NH4+-prepulse-induced intracellular acidification are unaffected by carbonic anhydrase inhibition. Extracellular surface pH transients induced by transmembrane NH3 flux are evident under CO2/HCO3--free conditions but absent when the buffer capacity and apparent H+ mobility increase in the presence of CO2/HCO3- even after the inhibition of carbonic anhydrases. We conclude that (a) intracellular carbonic anhydrase activity accentuates pH transients and vasoconstriction in response to acute elevations of pCO2, (b) CO2/HCO3- minimizes extracellular surface pH transients without requiring carbonic anhydrase activity, and (c) carbonic anhydrases are not rate limiting for acid–base transport across cell membranes during recovery from intracellular acidification.
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Affiliation(s)
| | - Ebbe Boedtkjer
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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27
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Bonde L, Boedtkjer E. Extracellular acidosis and very low [Na + ] inhibit NBCn1- and NHE1-mediated net acid extrusion from mouse vascular smooth muscle cells. Acta Physiol (Oxf) 2017; 221:129-141. [PMID: 28319329 DOI: 10.1111/apha.12877] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 02/20/2017] [Accepted: 03/14/2017] [Indexed: 12/28/2022]
Abstract
AIM The electroneutral Na+ , HCO3- cotransporter NBCn1 and Na+ /H+ exchanger NHE1 regulate acid-base balance in vascular smooth muscle cells (VSMCs) and modify artery function and structure. Pathological conditions - notably ischaemia - can dramatically perturb intracellular (i) and extracellular (o) pH and [Na+ ]. We examined effects of low [Na+ ]o and pHo on NBCn1 and NHE1 activity in VSMCs of small arteries. METHODS We measured pHi by 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein-based fluorescence microscopy of mouse mesenteric arteries and induced intracellular acidification by NH4+ prepulse technique. RESULTS NBCn1 activity - defined as Na+ -dependent, amiloride-insensitive net base uptake with CO2 /HCO3- present - was inhibited equally when pHo decreased from 7.4 (22 mm HCO3-/5% CO2 ) by metabolic (pHo 7.1/11 mm HCO3-: 22 ± 8%; pHo 6.8/5.5 mm HCO3-: 61 ± 7%) or respiratory (pHo 7.1/10% CO2 : 35 ± 11%; pHo 6.8/20% CO2 : 56 ± 7%) acidosis. Extracellular acidosis more prominently inhibited NHE1 activity - defined as Na+ -dependent net acid extrusion without CO2 /HCO3- present - at both pHo 7.1 (45 ± 9%) and 6.8 (85 ± 5%). Independently of pHo , lowering [Na+ ]o from 140 to 70 mm reduced NBCn1 and NHE1 activity <20% whereas transport activities declined markedly (25-50%) when [Na+ ]o was reduced to 35 mm. Steady-state pHi decreased more during respiratory (ΔpHi /ΔpHo = 71 ± 4%) than metabolic (ΔpHi /ΔpHo = 30 ± 7%) acidosis. CONCLUSION Extracellular acidification inhibits NBCn1 and NHE1 activity in VSMCs. NBCn1 is equivalently inhibited when pCO2 is raised or [HCO3-]o decreased. Lowering [Na+ ]o inhibits NBCn1 and NHE1 markedly only below the typical physiological and pathophysiological range. We propose that inhibition of Na+ -dependent net acid extrusion at low pHo protects against cellular Na+ overload at the cost of intracellular acidification.
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Affiliation(s)
- L. Bonde
- Department of Biomedicine; Aarhus University; Aarhus Denmark
| | - E. Boedtkjer
- Department of Biomedicine; Aarhus University; Aarhus Denmark
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28
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Kreitzer MA, Swygart D, Osborn M, Skinner B, Heer C, Kaufman R, Williams B, Shepherd L, Caringal H, Gongwer M, Tchernookova BK, Malchow RP. Extracellular H + fluxes from tiger salamander Müller (glial) cells measured using self-referencing H +-selective microelectrodes. J Neurophysiol 2017; 118:3132-3143. [PMID: 28855292 DOI: 10.1152/jn.00409.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 08/18/2017] [Accepted: 08/25/2017] [Indexed: 12/22/2022] Open
Abstract
Self-referencing H+-selective electrodes were used to measure extracellular H+ fluxes from Müller (glial) cells isolated from the tiger salamander retina. A novel chamber enabled stable recordings using H+-selective microelectrodes in a self-referencing format using bicarbonate-based buffer solutions. A small basal H+ flux was observed from the end foot region of quiescent cells bathed in 24 mM bicarbonate-based solutions, and increasing extracellular potassium induced a dose-dependent increase in H+ flux. Barium at 6 mM also increased H+ flux. Potassium-induced extracellular acidifications were abolished when bicarbonate was replaced by 1 mM HEPES. The carbonic anhydrase antagonist benzolamide potentiated the potassium-induced extracellular acidification, while 300 μM DIDS, 300 μM SITS, and 30 μM S0859 significantly reduced the response. Potassium-induced extracellular acidifications persisted in solutions lacking extracellular calcium, although potassium-induced changes in intracellular calcium monitored with Oregon Green were abolished. Exchange of external sodium with choline also eliminated the potassium-induced extracellular acidification. Removal of extracellular sodium by itself induced a transient alkalinization, and replacement of sodium induced a transient acidification, both of which were blocked by 300 μM DIDS. Recordings at the apical portion of the cell showed smaller potassium-induced extracellular H+ fluxes, and removal of the end foot region further decreased the H+ flux, suggesting that the end foot was the major source of acidifications. These studies demonstrate that self-referencing H+-selective electrodes can be used to monitor H+ fluxes from retinal Müller cells in bicarbonate-based solutions and confirm the presence of a sodium-coupled bicarbonate transporter, the activity of which is largely restricted to the end foot of the cell.NEW & NOTEWORTHY The present study uses self-referencing H+-selective electrodes for the first time to measure H+ fluxes from Müller (glial) cells isolated from tiger salamander retina. These studies demonstrate bicarbonate transport as a potent regulator of extracellular levels of acidity around Müller cells and point toward a need for further studies aimed at addressing how such glial cell pH regulatory mechanisms may shape neuronal signaling.
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Affiliation(s)
| | - David Swygart
- Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Meredith Osborn
- Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Blair Skinner
- Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Chad Heer
- Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Ryan Kaufman
- Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Bethany Williams
- Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Lexi Shepherd
- Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Hannah Caringal
- Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Michael Gongwer
- Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Boriana K Tchernookova
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois; and
| | - Robert P Malchow
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois; and.,Ophthalmology & Visual Sciences, University of Illinois at Chicago, Chicago, Illinois
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Praetorius J, Damkier HH. Transport across the choroid plexus epithelium. Am J Physiol Cell Physiol 2017; 312:C673-C686. [PMID: 28330845 DOI: 10.1152/ajpcell.00041.2017] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 03/17/2017] [Accepted: 03/17/2017] [Indexed: 11/22/2022]
Abstract
The choroid plexus epithelium is a secretory epithelium par excellence. However, this is perhaps not the most prominent reason for the massive interest in this modest-sized tissue residing inside the brain ventricles. Most likely, the dominant reason for extensive studies of the choroid plexus is the identification of this epithelium as the source of the majority of intraventricular cerebrospinal fluid. This finding has direct relevance for studies of diseases and conditions with deranged central fluid volume or ionic balance. While the concept is supported by the vast majority of the literature, the implication of the choroid plexus in secretion of the cerebrospinal fluid was recently challenged once again. Three newer and promising areas of current choroid plexus-related investigations are as follows: 1) the choroid plexus epithelium as the source of mediators necessary for central nervous system development, 2) the choroid plexus as a route for microorganisms and immune cells into the central nervous system, and 3) the choroid plexus as a potential route for drug delivery into the central nervous system, bypassing the blood-brain barrier. Thus, the purpose of this review is to highlight current active areas of research in the choroid plexus physiology and a few matters of continuous controversy.
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Affiliation(s)
- Jeppe Praetorius
- Department of Biomedicine, Health, Aarhus University, Aarhus, Denmark; and
| | - Helle Hasager Damkier
- Department of Biomedicine, Health, Aarhus University, Aarhus, Denmark; and.,Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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McGinley C, Bishop DJ. Influence of training intensity on adaptations in acid/base transport proteins, muscle buffer capacity, and repeated-sprint ability in active men. J Appl Physiol (1985) 2016; 121:1290-1305. [DOI: 10.1152/japplphysiol.00630.2016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 10/03/2016] [Accepted: 10/06/2016] [Indexed: 11/22/2022] Open
Abstract
McGinley C, Bishop DJ. Influence of training intensity on adaptations in acid/base transport proteins, muscle buffer capacity, and repeated-sprint ability in active men. J Appl Physiol 121: 1290–1305, 2016. First published October 14, 2016; doi: 10.1152/japplphysiol.00630.2016 .—This study measured the adaptive response to exercise training for each of the acid-base transport protein families, including providing isoform-specific evidence for the monocarboxylate transporter (MCT)1/4 chaperone protein basigin and for the electrogenic sodium-bicarbonate cotransporter (NBCe)1. We investigated whether 4 wk of work-matched, high-intensity interval training (HIIT), performed either just above the lactate threshold (HIITΔ20; n = 8), or close to peak aerobic power (HIITΔ90; n = 8), influenced adaptations in acid-base transport protein abundance, nonbicarbonate muscle buffer capacity (βmin vitro), and exercise capacity in active men. Training intensity did not discriminate between adaptations for most proteins measured, with abundance of MCT1, sodium/hydrogen exchanger (NHE) 1, NBCe1, carbonic anhydrase (CA) II, and CAXIV increasing after 4 wk, whereas there was little change in CAIII and CAIV abundance. βmin vitro also did not change. However, MCT4 protein content only increased for HIITΔ20 [effect size (ES): 1.06, 90% confidence limits × / ÷ 0.77], whereas basigin protein content only increased for HIITΔ90 (ES: 1.49, × / ÷ 1.42). Repeated-sprint ability (5 × 6-s sprints; 24 s passive rest) improved similarly for both groups. Power at the lactate threshold only improved for HIITΔ20 (ES: 0.49; 90% confidence limits ± 0.38), whereas peak O2 uptake did not change for either group. Detraining was characterized by the loss of adaptations for all of the proteins measured and for repeated-sprint ability 6 wk after removing the stimulus of HIIT. In conclusion, 4 wk of HIIT induced improvements in each of the acid-base transport protein families, but, remarkably, a 40% difference in training intensity did not discriminate between most adaptations.
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Affiliation(s)
- Cian McGinley
- College of Sport and Exercise Science, Victoria University, Melbourne, Victoria, Australia; and
| | - David J. Bishop
- College of Sport and Exercise Science, Victoria University, Melbourne, Victoria, Australia; and
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Victoria, Australia
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31
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Hladky SB, Barrand MA. Fluid and ion transfer across the blood-brain and blood-cerebrospinal fluid barriers; a comparative account of mechanisms and roles. Fluids Barriers CNS 2016; 13:19. [PMID: 27799072 PMCID: PMC5508927 DOI: 10.1186/s12987-016-0040-3] [Citation(s) in RCA: 156] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 09/01/2016] [Indexed: 12/24/2022] Open
Abstract
The two major interfaces separating brain and blood have different primary roles. The choroid plexuses secrete cerebrospinal fluid into the ventricles, accounting for most net fluid entry to the brain. Aquaporin, AQP1, allows water transfer across the apical surface of the choroid epithelium; another protein, perhaps GLUT1, is important on the basolateral surface. Fluid secretion is driven by apical Na+-pumps. K+ secretion occurs via net paracellular influx through relatively leaky tight junctions partially offset by transcellular efflux. The blood-brain barrier lining brain microvasculature, allows passage of O2, CO2, and glucose as required for brain cell metabolism. Because of high resistance tight junctions between microvascular endothelial cells transport of most polar solutes is greatly restricted. Because solute permeability is low, hydrostatic pressure differences cannot account for net fluid movement; however, water permeability is sufficient for fluid secretion with water following net solute transport. The endothelial cells have ion transporters that, if appropriately arranged, could support fluid secretion. Evidence favours a rate smaller than, but not much smaller than, that of the choroid plexuses. At the blood-brain barrier Na+ tracer influx into the brain substantially exceeds any possible net flux. The tracer flux may occur primarily by a paracellular route. The blood-brain barrier is the most important interface for maintaining interstitial fluid (ISF) K+ concentration within tight limits. This is most likely because Na+-pumps vary the rate at which K+ is transported out of ISF in response to small changes in K+ concentration. There is also evidence for functional regulation of K+ transporters with chronic changes in plasma concentration. The blood-brain barrier is also important in regulating HCO3- and pH in ISF: the principles of this regulation are reviewed. Whether the rate of blood-brain barrier HCO3- transport is slow or fast is discussed critically: a slow transport rate comparable to those of other ions is favoured. In metabolic acidosis and alkalosis variations in HCO3- concentration and pH are much smaller in ISF than in plasma whereas in respiratory acidosis variations in pHISF and pHplasma are similar. The key similarities and differences of the two interfaces are summarized.
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Affiliation(s)
- Stephen B. Hladky
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD UK
| | - Margery A. Barrand
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD UK
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Melis C, Meleddu R, Angeli A, Distinto S, Bianco G, Capasso C, Cottiglia F, Angius R, Supuran CT, Maccioni E. Isatin: a privileged scaffold for the design of carbonic anhydrase inhibitors. J Enzyme Inhib Med Chem 2016; 32:68-73. [PMID: 27775452 PMCID: PMC6010117 DOI: 10.1080/14756366.2016.1235042] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The isatin scaffold is the constitutive fragment of several natural and synthetic bioactive molecules. Albeit several benzene sulphonamide-based carbonic anhydrase inhibitors (CAIs) have been reported, only recently isatin benzene sulphonamides have been studied and proposed as CAIs. In this study we have designed, synthesised, and evaluated the biological activity of a series of differently substituted isatin-based benzene sulphonamides which have been designed for the inhibition of carbonic anhydrase isoforms. The activity of all the synthesised compounds was evaluated towards human carbonic anhydrase I, II, IX, and XII isozymes. Our results indicate that the nature and position of substituents on the isatin ring can modulate both activity and isozyme selectivity.
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Affiliation(s)
- Claudia Melis
- a Department of Life and Environmental Sciences , University of Cagliari , Cagliari , Italy
| | - Rita Meleddu
- a Department of Life and Environmental Sciences , University of Cagliari , Cagliari , Italy
| | - Andrea Angeli
- b Dipartimento NEUROFARBA, Sezione di Scienze Farmaceutiche , Università degli Studi di Firenze , Sesto Fiorentino , Florence , Italy
| | - Simona Distinto
- a Department of Life and Environmental Sciences , University of Cagliari , Cagliari , Italy
| | - Giulia Bianco
- a Department of Life and Environmental Sciences , University of Cagliari , Cagliari , Italy
| | | | - Filippo Cottiglia
- a Department of Life and Environmental Sciences , University of Cagliari , Cagliari , Italy
| | - Rossella Angius
- d Laboratorio NMR e Tecnologie Bioanalitiche, Sardegna Ricerche , Pula , CA , Italy
| | - Claudiu T Supuran
- b Dipartimento NEUROFARBA, Sezione di Scienze Farmaceutiche , Università degli Studi di Firenze , Sesto Fiorentino , Florence , Italy
| | - Elias Maccioni
- a Department of Life and Environmental Sciences , University of Cagliari , Cagliari , Italy
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Meleddu R, Maccioni E, Distinto S, Bianco G, Melis C, Alcaro S, Cottiglia F, Ceruso M, Supuran CT. New 4-[(3-cyclohexyl-4-aryl-2,3-dihydro-1,3-thiazol-2-ylidene)amino]benzene-1-sulfonamides, synthesis and inhibitory activity toward carbonic anhydrase I, II, IX, XII. Bioorg Med Chem Lett 2015; 25:3281-4. [PMID: 26073006 DOI: 10.1016/j.bmcl.2015.05.076] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 05/21/2015] [Accepted: 05/23/2015] [Indexed: 11/18/2022]
Abstract
A series of 4-[(3-cyclohexyl-4-aryl-2,3-dihydro-1,3-thiazol-2-ylidene)amino]benzene-1-sulfonamides was synthesised and the activity of the new compounds as inhibitors of hCA I, II, IX, and XII was evaluated. These new derivatives exhibited some peculiarities with respect to previously reported sulfonamide based inhibitors of CA. We observed that the nature of the substituents in the position 3 and 4 of the dihydro-thiazole ring was relevant in determining both activity and selectivity profiles.
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Affiliation(s)
- Rita Meleddu
- Department of Life and Environmental Sciences, University of Cagliari, Via Ospedale 72, 09124 Cagliari, Italy
| | - Elias Maccioni
- Department of Life and Environmental Sciences, University of Cagliari, Via Ospedale 72, 09124 Cagliari, Italy.
| | - Simona Distinto
- Department of Life and Environmental Sciences, University of Cagliari, Via Ospedale 72, 09124 Cagliari, Italy
| | - Giulia Bianco
- Department of Life and Environmental Sciences, University of Cagliari, Via Ospedale 72, 09124 Cagliari, Italy
| | - Claudia Melis
- Department of Life and Environmental Sciences, University of Cagliari, Via Ospedale 72, 09124 Cagliari, Italy
| | - Stefano Alcaro
- Dipartimento di Scienze della Salute, Università Magna Graecia di Catanzaro, Campus 'S. Venuta', Viale Europa, 88100 Catanzaro, Italy
| | - Filippo Cottiglia
- Department of Life and Environmental Sciences, University of Cagliari, Via Ospedale 72, 09124 Cagliari, Italy
| | - Mariangela Ceruso
- Dipartimento NEUROFARBA, Sezione di Scienze Farmaceutiche, Università degli Studi di Firenze, Sesto Fiorentino, Florence, Italy
| | - Claudiu T Supuran
- Dipartimento NEUROFARBA, Sezione di Scienze Farmaceutiche, Università degli Studi di Firenze, Sesto Fiorentino, Florence, Italy
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Hektoen HH, Ree AH, Redalen KR, Flatmark K. Sulfamate inhibitor S4 influences carbonic anhydrase IX ectodomain shedding in colorectal carcinoma cells. J Enzyme Inhib Med Chem 2015; 31:779-86. [PMID: 26244271 DOI: 10.3109/14756366.2015.1069286] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Carbonic anhydrase IX (CAIX) is a pivotal pH regulator under hypoxia, which by its tumor-specific expression represents an attractive target for cancer therapy. Here, we report on effects of the sulfamate CAIX inhibitor S4 (4-(3'-(3″,5″-dimethylphenyl)ureido)phenyl sulfamate) in colorectal carcinoma cell lines. S4 was administered under experimental hypoxia or normoxia to HT29, KM20L2 and HCT116 cells. Effects on survival, proliferation, pH, lactate extrusion and CAIX protein expression were evaluated. S4 treatment resulted in attenuated hypoxia-induced extracellular acidification and reduced clonogenic survival under hypoxia in HT29 cells. The pH effects were present only in a [Formula: see text]-free buffer system and were accompanied by decreased lactate extrusion. The main finding of this work was that S4 treatment caused alterations in CAIX ectodomain shedding. This merits further investigation to understand how sulfamates influence CAIX activity and how such drugs may be of use in cancer treatment.
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Affiliation(s)
- Helga Helseth Hektoen
- a Institute of Clinical Medicine, University of Oslo , Oslo , Norway .,b Department of Tumor Biology , Oslo University Hospital , Oslo , Norway .,c Department of Oncology , Akershus University Hospital , Lørenskog , Norway , and
| | - Anne Hansen Ree
- a Institute of Clinical Medicine, University of Oslo , Oslo , Norway .,c Department of Oncology , Akershus University Hospital , Lørenskog , Norway , and
| | - Kathrine Røe Redalen
- c Department of Oncology , Akershus University Hospital , Lørenskog , Norway , and
| | - Kjersti Flatmark
- a Institute of Clinical Medicine, University of Oslo , Oslo , Norway .,b Department of Tumor Biology , Oslo University Hospital , Oslo , Norway .,d Department of Gastroenterological Surgery , Oslo University Hospital , Oslo , Norway
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Díaz-Torres NA, Mahon BP, Boone CD, Pinard MA, Tu C, Ng R, Agbandje-McKenna M, Silverman D, Scott K, McKenna R. Structural and biophysical characterization of the α-carbonic anhydrase from the gammaproteobacterium Thiomicrospira crunogena XCL-2: insights into engineering thermostable enzymes for CO2 sequestration. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2015; 71:1745-56. [PMID: 26249355 PMCID: PMC4528804 DOI: 10.1107/s1399004715012183] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 06/24/2015] [Indexed: 11/10/2022]
Abstract
Biocatalytic CO2 sequestration to reduce greenhouse-gas emissions from industrial processes is an active area of research. Carbonic anhydrases (CAs) are attractive enzymes for this process. However, the most active CAs display limited thermal and pH stability, making them less than ideal. As a result, there is an ongoing effort to engineer and/or find a thermostable CA to fulfill these needs. Here, the kinetic and thermal characterization is presented of an α-CA recently discovered in the mesophilic hydrothermal vent-isolate extremophile Thiomicrospira crunogena XCL-2 (TcruCA), which has a significantly higher thermostability compared with human CA II (melting temperature of 71.9°C versus 59.5°C, respectively) but with a tenfold decrease in the catalytic efficiency. The X-ray crystallographic structure of the dimeric TcruCA shows that it has a highly conserved yet compact structure compared with other α-CAs. In addition, TcruCA contains an intramolecular disulfide bond that stabilizes the enzyme. These features are thought to contribute significantly to the thermostability and pH stability of the enzyme and may be exploited to engineer α-CAs for applications in industrial CO2 sequestration.
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Affiliation(s)
- Natalia A. Díaz-Torres
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Brian P. Mahon
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Christopher D. Boone
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Melissa A. Pinard
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Chingkuang Tu
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Robert Ng
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Mavis Agbandje-McKenna
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - David Silverman
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Kathleen Scott
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620, USA
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, FL 32610, USA
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Abstract
Cation-coupled HCO3(-) transport was initially identified in the mid-1970s when pioneering studies showed that acid extrusion from cells is stimulated by CO2/HCO3(-) and associated with Na(+) and Cl(-) movement. The first Na(+)-coupled bicarbonate transporter (NCBT) was expression-cloned in the late 1990s. There are currently five mammalian NCBTs in the SLC4-family: the electrogenic Na,HCO3-cotransporters NBCe1 and NBCe2 (SLC4A4 and SLC4A5 gene products); the electroneutral Na,HCO3-cotransporter NBCn1 (SLC4A7 gene product); the Na(+)-driven Cl,HCO3-exchanger NDCBE (SLC4A8 gene product); and NBCn2/NCBE (SLC4A10 gene product), which has been characterized as an electroneutral Na,HCO3-cotransporter or a Na(+)-driven Cl,HCO3-exchanger. Despite the similarity in amino acid sequence and predicted structure among the NCBTs of the SLC4-family, they exhibit distinct differences in ion dependency, transport function, pharmacological properties, and interactions with other proteins. In epithelia, NCBTs are involved in transcellular movement of acid-base equivalents and intracellular pH control. In nonepithelial tissues, NCBTs contribute to intracellular pH regulation; and hence, they are crucial for diverse tissue functions including neuronal discharge, sensory neuron development, performance of the heart, and vascular tone regulation. The function and expression levels of the NCBTs are generally sensitive to intracellular and systemic pH. Animal models have revealed pathophysiological roles of the transporters in disease states including metabolic acidosis, hypertension, visual defects, and epileptic seizures. Studies are being conducted to understand the physiological consequences of genetic polymorphisms in the SLC4-members, which are associated with cancer, hypertension, and drug addiction. Here, we describe the current knowledge regarding the function, structure, and regulation of the mammalian cation-coupled HCO3(-) transporters of the SLC4-family.
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Affiliation(s)
- Christian Aalkjaer
- Department of Biomedicine, and the Water and Salt Research Center, Aarhus University, Aarhus, Denmark; Department of Physiology, Emory University School of Medicine, Atlanta, USA
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Carre G, Ouedraogo M, Magaud C, Carreyre H, Becq F, Bois P, Supuran CT, Thibaudeau S, Vandebrouck C, Bescond J. Vasorelaxation induced by dodoneine is mediated by calcium channels blockade and carbonic anhydrase inhibition on vascular smooth muscle cells. JOURNAL OF ETHNOPHARMACOLOGY 2015; 169:8-17. [PMID: 25847623 DOI: 10.1016/j.jep.2015.03.037] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 03/05/2015] [Accepted: 03/12/2015] [Indexed: 06/04/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Dodoneine (Ddn) is one of the active compounds identified from Agelanthus dodoneifolius (DC.) Polhill and Wiens, a medicinal plant used in traditional medicine for the treatment of hypertension. This dihydropyranone exerts hypotensive and vasorelaxant effects on rats, and two molecular targets have been characterized: the carbonic anhydrase and the L-type calcium channel in cardiomyocytes with biochemical and electrophysiological techniques, respectively. To further evaluate the involvement of these two molecular targets in vasorelaxation, the effect of Ddn on rat vascular smooth muscle was investigated. MATERIAL AND METHODS The effects of Ddn on L-type calcium current and on resting membrane potential were characterized in A7r5 cell line using the whole-cell patch-clamp configuration. The molecular identities of carbonic anhydrase isozymes in smooth muscle cells were examined with RT-PCR. Vascular response was measured on rat aortic rings in an organ bath apparatus and the effect of Ddn on intracellular pH was determined by flow cytometry using the pH-sensitive fluorescent probe BCECF-AM [2,7-Bis-(2-Carboxyethyl)-5-(and-6)-Carboxyfluorescein, Acetoxymethyl Ester]. RESULTS 100µM Ddn reduced calcium current density of about 30%. In addition, carbonic anhydrase II, III, XIII and XIV were shown to be expressed in rat aorta and inhibited in smooth muscle cells by Ddn. This inhibition resulted in a rise in pHi of about 0.31, leading to KCa channel activation, thereby inducing membrane hyperpolarization and vasorelaxation. The results of vascular reactivity experiments obtained with pharmacological tools acting on the L-type calcium current and carbonic anhydrase suggest that Ddn produces its vasorelaxant effect via the inhibition of these two molecular targets. CONCLUSION This study demonstrates that Ddn induced vasorelaxation by targeting two proteins involved in the modulation of excitation-contraction coupling: L-type calcium channels and carbonic anhydrase.
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Affiliation(s)
- Grégoire Carre
- Signalisation et Transports Ioniques Membranaires, Université de Poitiers, CNRS ERL 7368; 1 rue Georges Bonnet F-86073 Poitiers Cedex 09, France
| | - Maurice Ouedraogo
- Laboratoire de Physiologie Animale, Université de Ouagadougou, 03 BP 7021, Ouagadougou 01, Burkina Faso
| | - Christophe Magaud
- Signalisation et Transports Ioniques Membranaires, Université de Poitiers, CNRS ERL 7368; 1 rue Georges Bonnet F-86073 Poitiers Cedex 09, France
| | - Hélène Carreyre
- Superacid group in "Organic Synthesis" team, Université de Poitiers, CNRS UMR 7285 IC2MP, 4 avenue Michel Brunet, Poitiers 86022 Cedex, France
| | - Frédéric Becq
- Signalisation et Transports Ioniques Membranaires, Université de Poitiers, CNRS ERL 7368; 1 rue Georges Bonnet F-86073 Poitiers Cedex 09, France
| | - Patrick Bois
- Signalisation et Transports Ioniques Membranaires, Université de Poitiers, CNRS ERL 7368; 1 rue Georges Bonnet F-86073 Poitiers Cedex 09, France
| | - Claudiu T Supuran
- Università degli Studi di Firenze, Laboratorio di Chimica Bioinorganica, Rm 188, Via della Lastruccia 3, I-50019 Sesto Fiorentino (Firenze), Italy
| | - Sébastien Thibaudeau
- Superacid group in "Organic Synthesis" team, Université de Poitiers, CNRS UMR 7285 IC2MP, 4 avenue Michel Brunet, Poitiers 86022 Cedex, France
| | - Clarisse Vandebrouck
- Signalisation et Transports Ioniques Membranaires, Université de Poitiers, CNRS ERL 7368; 1 rue Georges Bonnet F-86073 Poitiers Cedex 09, France
| | - Jocelyn Bescond
- Signalisation et Transports Ioniques Membranaires, Université de Poitiers, CNRS ERL 7368; 1 rue Georges Bonnet F-86073 Poitiers Cedex 09, France.
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Auger C, Appanna ND, Alhasawi A, Appanna VD. Deciphering metabolic networks by blue native polyacrylamide gel electrophoresis: A functional proteomic exploration. EUPA OPEN PROTEOMICS 2015. [DOI: 10.1016/j.euprot.2015.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Buelli S, Perico L, Galbusera M, Abbate M, Morigi M, Novelli R, Gagliardini E, Tentori C, Rottoli D, Sabadini E, Saito T, Kawano M, Saeki T, Zoja C, Remuzzi G, Benigni A. Mitochondrial-dependent Autoimmunity in Membranous Nephropathy of IgG4-related Disease. EBioMedicine 2015; 2:456-66. [PMID: 26137589 PMCID: PMC4485911 DOI: 10.1016/j.ebiom.2015.03.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 03/04/2015] [Accepted: 03/05/2015] [Indexed: 01/13/2023] Open
Abstract
The pathophysiology of glomerular lesions of membranous nephropathy (MN), including seldom-reported IgG4-related disease, is still elusive. Unlike in idiopathic MN where IgG4 prevails, in this patient IgG3 was predominant in glomerular deposits in the absence of circulating anti-phospholipase A2 receptor antibodies, suggesting a distinct pathologic process. Here we documented that IgG4 retrieved from the serum of our propositus reacted against carbonic anhydrase II (CAII) at the podocyte surface. In patient's biopsy, glomerular CAII staining increased and co-localized with subepithelial IgG4 deposits along the capillary walls. Patient's IgG4 caused a drop in cell pH followed by mitochondrial dysfunction, excessive ROS production and cytoskeletal reorganization in cultured podocytes. These events promoted mitochondrial superoxide-dismutase-2 (SOD2) externalization on the plasma membrane, becoming recognizable by complement-binding IgG3 anti-SOD2. Among patients with IgG4-related disease only sera of those with IgG4 anti-CAII antibodies caused low intracellular pH and mitochondrial alterations underlying SOD2 externalization. Circulating IgG4 anti-CAII can cause podocyte injury through processes of intracellular acidification, mitochondrial oxidative stress and neoantigen induction in patients with IgG4 related disease. The onset of MN in a subset of patients could be due to IgG4 antibodies recognizing CAII with consequent exposure of mitochondrial neoantigen in the context of multifactorial pathogenesis of disease. In a patient with IgG4-related disease, glomerular CAII increases and colocalizes with IgG4 deposits. IgG4 from patient's serum reacts against CAII expressed by podocytes. IgG4 causes acidification, mitochondrial dysfunction and ROS-dependent cytoskeletal alterations in cultured podocytes. IgG4 induces the externalization on the plasma membrane of clustered SOD2, becoming recognizable by complement-binding IgG3.
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Affiliation(s)
- Simona Buelli
- IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri", Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Luca Perico
- IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri", Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Miriam Galbusera
- IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri", Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Mauro Abbate
- IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri", Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Marina Morigi
- IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri", Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Rubina Novelli
- IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri", Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Elena Gagliardini
- IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri", Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Chiara Tentori
- IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri", Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Daniela Rottoli
- IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri", Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Ettore Sabadini
- Unit of Nephrology and Dialysis, Azienda Ospedaliera Papa Giovanni XXIII, Bergamo, Italy
| | - Takao Saito
- General Medical Research Center, Faculty of Medicine, Fukuoka University, Japan
| | - Mitsuhiro Kawano
- Department of Rheumatology, University School of Medicine, Kanazawa, Japan
| | - Takako Saeki
- Department of Internal Medicine, Red Cross Hospital, Nagaoka, Japan
| | - Carlamaria Zoja
- IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri", Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Giuseppe Remuzzi
- IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri", Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy ; Unit of Nephrology and Dialysis, Azienda Ospedaliera Papa Giovanni XXIII, Bergamo, Italy
| | - Ariela Benigni
- IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri", Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
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Brasen JC, Burford JL, McDonough AA, Holstein-Rathlou NH, Peti-Peterdi J. Local pH domains regulate NHE3-mediated Na⁺ reabsorption in the renal proximal tubule. Am J Physiol Renal Physiol 2014; 307:F1249-62. [PMID: 25298526 DOI: 10.1152/ajprenal.00174.2014] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The proximal tubule Na(+)/H(+) exchanger 3 (NHE3), located in the apical dense microvilli (brush border), plays a major role in the reabsorption of NaCl and water in the renal proximal tubule. In response to a rise in blood pressure NHE3 redistributes in the plane of the plasma membrane to the base of the brush border, where NHE3 activity is reduced. This NHE3 redistribution is assumed to provoke pressure natriuresis; however, it is unclear how NHE3 redistribution per se reduces NHE3 activity. To investigate if the distribution of NHE3 in the brush border can change the reabsorption rate, we constructed a spatiotemporal mathematical model of NHE3-mediated Na(+) reabsorption across a proximal tubule cell and compared the model results with in vivo experiments in rats. The model predicts that when NHE3 is localized exclusively at the base of the brush border, it creates local pH microdomains that reduce NHE3 activity by >30%. We tested the model's prediction experimentally: the rat kidney cortex was loaded with the pH-sensitive fluorescent dye BCECF, and cells of the proximal tubule were imaged in vivo using confocal fluorescence microscopy before and after an increase of blood pressure by ∼50 mmHg. The experimental results supported the model by demonstrating that a rise of blood pressure induces the development of pH microdomains near the bottom of the brush border. These local changes in pH reduce NHE3 activity, which may explain the pressure natriuresis response to NHE3 redistribution.
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Affiliation(s)
- Jens Christian Brasen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; Biomedical Engineering, Department of Electrical Engineering, Technical University of Denmark, Lyngby, Denmark; and
| | - James L Burford
- Departments of Physiology and Biophysics and Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California; and
| | - Alicia A McDonough
- Department of Cell and Neurobiology, University of Southern California, Los Angeles, California
| | | | - Janos Peti-Peterdi
- Departments of Physiology and Biophysics and Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California; and
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Hulikova A, Aveyard N, Harris AL, Vaughan-Jones RD, Swietach P. Intracellular carbonic anhydrase activity sensitizes cancer cell pH signaling to dynamic changes in CO2 partial pressure. J Biol Chem 2014; 289:25418-30. [PMID: 25059669 PMCID: PMC4162147 DOI: 10.1074/jbc.m114.547844] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 07/21/2014] [Indexed: 12/11/2022] Open
Abstract
Carbonic anhydrase (CA) enzymes catalyze the chemical equilibration among CO2, HCO3(-) and H(+). Intracellular CA (CAi) isoforms are present in certain types of cancer, and growing evidence suggests that low levels correlate with disease severity. However, their physiological role remains unclear. Cancer cell CAi activity, measured as cytoplasmic CO2 hydration rate (kf), ranged from high in colorectal HCT116 (∼2 s(-1)), bladder RT112 and colorectal HT29, moderate in fibrosarcoma HT1080 to negligible (i.e. spontaneous kf = 0.18 s(-1)) in cervical HeLa and breast MDA-MB-468 cells. CAi activity in cells correlated with CAII immunoreactivity and enzymatic activity in membrane-free lysates, suggesting that soluble CAII is an important intracellular isoform. CAi catalysis was not obligatory for supporting acid extrusion by H(+) efflux or HCO3(-) influx, nor for maintaining intracellular pH (pHi) uniformity. However, in the absence of CAi activity, acid loading from a highly alkaline pHi was rate-limited by HCO3(-) supply from spontaneous CO2 hydration. In solid tumors, time-dependence of blood flow can result in fluctuations of CO2 partial pressure (pCO2) that disturb cytoplasmic CO2-HCO3(-)-H(+) equilibrium. In cancer cells with high CAi activity, extracellular pCO2 fluctuations evoked faster and larger pHi oscillations. Functionally, these resulted in larger pH-dependent intracellular [Ca(2+)] oscillations and stronger inhibition of the mTORC1 pathway reported by S6 kinase phosphorylation. In contrast, the pHi of cells with low CAi activity was less responsive to pCO2 fluctuations. Such low pass filtering would "buffer" cancer cell pHi from non-steady-state extracellular pCO2. Thus, CAi activity determines the coupling between pCO2 (a function of tumor perfusion) and pHi (a potent modulator of cancer cell physiology).
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Affiliation(s)
- Alzbeta Hulikova
- From the Department of Physiology, Anatomy and Genetics, Oxford University, Parks Road, Oxford OX1 3PT, United Kingdom and
| | - Nicholas Aveyard
- From the Department of Physiology, Anatomy and Genetics, Oxford University, Parks Road, Oxford OX1 3PT, United Kingdom and
| | - Adrian L Harris
- Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford University, Oxford OX3 9DS, United Kingdom
| | - Richard D Vaughan-Jones
- From the Department of Physiology, Anatomy and Genetics, Oxford University, Parks Road, Oxford OX1 3PT, United Kingdom and
| | - Pawel Swietach
- From the Department of Physiology, Anatomy and Genetics, Oxford University, Parks Road, Oxford OX1 3PT, United Kingdom and
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Nishigaki T, José O, González-Cota AL, Romero F, Treviño CL, Darszon A. Intracellular pH in sperm physiology. Biochem Biophys Res Commun 2014; 450:1149-58. [PMID: 24887564 PMCID: PMC4146485 DOI: 10.1016/j.bbrc.2014.05.100] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 05/22/2014] [Indexed: 10/25/2022]
Abstract
Intracellular pH (pHi) regulation is essential for cell function. Notably, several unique sperm ion transporters and enzymes whose elimination causes infertility are either pHi dependent or somehow related to pHi regulation. Amongst them are: CatSper, a Ca(2+) channel; Slo3, a K(+) channel; the sperm-specific Na(+)/H(+) exchanger and the soluble adenylyl cyclase. It is thus clear that pHi regulation is of the utmost importance for sperm physiology. This review briefly summarizes the key components involved in pHi regulation, their characteristics and participation in fundamental sperm functions such as motility, maturation and the acrosome reaction.
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Affiliation(s)
- Takuya Nishigaki
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico
| | - Omar José
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico
| | - Ana Laura González-Cota
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico
| | - Francisco Romero
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico
| | - Claudia L Treviño
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico
| | - Alberto Darszon
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico.
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Balter V, Lamboux A, Zazzo A, Télouk P, Leverrier Y, Marvel J, Moloney AP, Monahan FJ, Schmidt O, Albarède F. Contrasting Cu, Fe, and Zn isotopic patterns in organs and body fluids of mice and sheep, with emphasis on cellular fractionation. Metallomics 2014; 5:1470-82. [PMID: 23963064 DOI: 10.1039/c3mt00151b] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We report Cu, Fe, and Zn natural isotope compositions in organs, body fluids, diets and feces of mice and sheep. Large and systematic isotope variability is observed, notably in the δ(66)Zn in liver and δ(65)Cu in kidneys, but significant differences exist between mice, sheep and humans, especially in the δ(66)Zn value of blood. The results are interpreted with reference to current knowledge of metal trafficking and redox conditions in cells. In general, the light isotopes preferentially fractionate into 'softer' bonds involving sulfur such as cysteine and glutathione, whereas heavy isotopes fractionate into 'harder' bonds involving nitrogen (histidine) and even more oxygen, notably hydroxides, phosphates, and carbonates. Bonds involving the reduced forms Cu(+) and Fe(2+) are enriched in the light isotopes relative to bonds involving the oxidized Cu(2+) and Fe(3+) forms. Differences in blood Zn isotope abundances between mice, sheep and humans may reflect a different prevalence of Zn ZIP transporters. The isotopically heavy Cu in the kidneys may reflect isotope fractionation during redox processes and may be relevant to ascorbate degradation into oxalate.
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Affiliation(s)
- Vincent Balter
- CNRS UMR 5276 "Laboratoire de Géologie de Lyon", Ecole Normale Supérieure. 46, Allée d'Italie, 69634 Lyon, France.
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Abstract
H(+) ions are remarkably efficient modulators of neuronal excitability. This renders brain functions highly sensitive to small changes in pH which are generated "extrinsically" via mechanisms that regulate the acid-base status of the whole organism; and "intrinsically", by activity-induced transmembrane fluxes and de novo generation of acid-base equivalents. The effects of pH changes on neuronal excitability are mediated by diverse, largely synergistically-acting mechanisms operating at the level of voltage- and ligand-gated ion channels and gap junctions. In general, alkaline shifts induce an increase in excitability which is often intense enough to trigger epileptiform activity, while acidosis has the opposite effect. Brain pH changes show a wide variability in their spatiotemporal properties, ranging from long-lasting global shifts to fast and highly localized transients that take place in subcellular microdomains. Thirteen catalytically-active mammalian carbonic anhydrase isoforms have been identified, whereof 11 are expressed in the brain. Distinct CA isoforms which have their catalytic sites within brain cells and the interstitial fluid exert a remarkably strong influence on the dynamics of pH shifts and, consequently, on neuronal functions. In this review, we will discuss the various roles of H(+) as an intra- and extracellular signaling factor in the brain, focusing on the effects mediated by CAs. Special attention is paid on the developmental expression patterns and actions of the neuronal isoform, CA VII. Studies on the various functions of CAs will shed light on fundamental mechanisms underlying neuronal development, signaling and plasticity; on pathophysiological mechanisms associated with epilepsy and related diseases; and on the modes of action of CA inhibitors used as CNS-targeting drugs.
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Affiliation(s)
- Eva Ruusuvuori
- Department of Biosciences, University of Helsinki, Helsinki, Finland,
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45
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Abstract
Carbonic anhydrases (CAs) catalyze a fundamental reaction: the reversible hydration and dehydration of carbon dioxide (CO2) and bicarbonate ([Formula: see text]), respectively. Current methods for CO2 capture and sequestration are harsh, expensive, and require prohibitively large energy inputs, effectively negating the purpose of removing CO2 from the atmosphere. Due to CA's activity on CO2 there is increasing interest in using CAs for industrial applications such as carbon sequestration and biofuel production. A lot of work in the last decade has focused on immobilizing CA onto various supports for incorporation into CO2 scrubbing applications or devices. Although the proof of principle has been validated, current CAs being tested do not withstand the harsh industrial conditions. The advent of large-scale genome sequencing projects has resulted in several emerging efforts seeking out novel CAs from a variety of microorganisms, including bacteria, micro-, and macro-algae. CAs are also being investigated for their use in medical applications, such drug delivery systems and artificial lungs. This review also looks at possible downstream uses of captured and sequestered CO2, from using it to enhance oil recovery to incorporating it into useful and financially viable products.
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Affiliation(s)
- Javier M González
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM, USA,
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Waheed A, Sly WS. Membrane associated carbonic anhydrase IV (CA IV): a personal and historical perspective. Subcell Biochem 2014; 75:157-79. [PMID: 24146379 DOI: 10.1007/978-94-007-7359-2_9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Carbonic anhydrase IV is one of 12 active human isozymes and one of four expressed on the extracellular surfaces of certain endothelial and epithelial cells. It is unique in being attached to the plasma membrane by a glycosyl-phosphatiydyl-inositol (GPI) anchor rather than by a membrane-spanning domain. It is also uniquely resistant to high concentrations of sodium dodecyl sulfate (SDS), which allows purification from tissues by inhibitor affinity chromatography without contamination by other isozymes. This unique resistance to SDS and recovery following denaturation is explained by the two disulfide bonds. The 35-kDa human CA IV is a "high activity" isozyme in CO2 hydration activity, like CA II, and has higher activity than other isozymes in catalyzing the dehydration of HCO3 (-). Human CA IV is also unique in that it contains no oligosaccharide chains, where all other mammalian CA IVs are glycoproteins with one to several oligosaccharide side chains.Although CA IV has been shown to be active in mediating CO2 and HCO3 (-) transport in many important tissues like kidney and lung, and in isolated cells from brain and muscle, the gene for CA IV appears not to be essential. The CA IV knockout mouse produced by targeted mutagenesis, though slightly smaller and produced in lower than expected numbers, is viable and has no obvious mutant phenotype. Conversely, several dominant negative mutations in humans are associated with one form of reitinitis pigmentosa (RP-17), which we attribute to unfolded protein accumulation in the choreocapillaris, leading to apoptosis of cells in the overlying retina.
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Affiliation(s)
- Abdul Waheed
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University, School of Medicine, St. Louis, MO, USA,
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Cordat E, Reithmeier RA. Structure, Function, and Trafficking of SLC4 and SLC26 Anion Transporters. CURRENT TOPICS IN MEMBRANES 2014; 73:1-67. [DOI: 10.1016/b978-0-12-800223-0.00001-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Abstract
This paper describes the interactions between ventilation and acid-base balance under a variety of conditions including rest, exercise, altitude, pregnancy, and various muscle, respiratory, cardiac, and renal pathologies. We introduce the physicochemical approach to assessing acid-base status and demonstrate how this approach can be used to quantify the origins of acid-base disorders using examples from the literature. The relationships between chemoreceptor and metaboreceptor control of ventilation and acid-base balance summarized here for adults, youth, and in various pathological conditions. There is a dynamic interplay between disturbances in acid-base balance, that is, exercise, that affect ventilation as well as imposed or pathological disturbances of ventilation that affect acid-base balance. Interactions between ventilation and acid-base balance are highlighted for moderate- to high-intensity exercise, altitude, induced acidosis and alkalosis, pregnancy, obesity, and some pathological conditions. In many situations, complete acid-base data are lacking, indicating a need for further research aimed at elucidating mechanistic bases for relationships between alterations in acid-base state and the ventilatory responses.
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Affiliation(s)
- Michael I Lindinger
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.
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Villafuerte FC, Swietach P, Youm JB, Ford K, Cardenas R, Supuran CT, Cobden PM, Rohling M, Vaughan-Jones RD. Facilitation by intracellular carbonic anhydrase of Na+ -HCO3- co-transport but not Na+ / H+ exchange activity in the mammalian ventricular myocyte. J Physiol 2013; 592:991-1007. [PMID: 24297849 PMCID: PMC3948559 DOI: 10.1113/jphysiol.2013.265439] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Carbonic anhydrase enzymes (CAs) catalyse the reversible hydration of CO2 to H+ and HCO3- ions. This catalysis is proposed to be harnessed by acid/base transporters, to facilitate their transmembrane flux activity, either through direct protein-protein binding (a 'transport metabolon') or local functional interaction. Flux facilitation has previously been investigated by heterologous co-expression of relevant proteins in host cell lines/oocytes. Here, we examine the influence of intrinsic CA activity on membrane HCO3- or H+ transport via the native acid-extruding proteins, Na+ -HCO3- cotransport (NBC) and Na+ / H+ exchange (NHE), expressed in enzymically isolated mammalian ventricular myocytes. Effects of intracellular and extracellular (exofacial) CA (CAi and CAe) are distinguished using membrane-permeant and -impermeant pharmacological CA inhibitors, while measuring transporter activity in the intact cell using pH and Na+ fluorophores. We find that NBC, but not NHE flux is enhanced by catalytic CA activity, with facilitation being confined to CAi activity alone. Results are quantitatively consistent with a model where CAi catalyses local H+ ion delivery to the NBC protein, assisting the subsequent (uncatalysed) protonation and removal of imported HCO3- ions. In well-superfused myocytes, exofacial CA activity is superfluous, most likely because extracellular CO2/HCO3- buffer is clamped at equilibrium. The CAi insensitivity of NHE flux suggests that, in the native cell, intrinsic mobile buffer-shuttles supply sufficient intracellular H+ ions to this transporter, while intrinsic buffer access to NBC proteins is restricted. Our results demonstrate a selective CA facilitation of acid/base transporters in the ventricular myocyte, implying a specific role for the intracellular enzyme in HCO3- transport, and hence pHi regulation in the heart.
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Affiliation(s)
- Francisco C Villafuerte
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK.
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Peña-Münzenmayer G, Niemeyer MI, Sepúlveda FV, Cid LP. Zebrafish and mouse TASK-2 K(+) channels are inhibited by increased CO2 and intracellular acidification. Pflugers Arch 2013; 466:1317-27. [PMID: 24081451 DOI: 10.1007/s00424-013-1365-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 09/12/2013] [Accepted: 09/13/2013] [Indexed: 11/28/2022]
Abstract
TASK-2 is a K2P K(+) channel considered as a candidate to mediate CO2 sensing in central chemosensory neurons in mouse. Neuroepithelial cells in zebrafish gills sense CO2 levels through an unidentified K2P K(+) channel. We have now obtained zfTASK-2 from zebrafish gill tissue that is 49 % identical to mTASK-2. Like its mouse equivalent, it is gated both by extra- and intracellular pH being activated by alkalinization and inhibited by acidification. The pHi dependence of zfTASK-2 is similar to that of mTASK-2, with pK 1/2 values of 7.9 and 8.0, respectively, but pHo dependence occurs with a pK 1/2 of 8.8 (8.0 for mTASK-2) in line with the relatively alkaline plasma pH found in fish. Increasing CO2 led to a rapid, concentration-dependent (IC50 ~1.5 % CO2) inhibition of mouse and zfTASK-2 that could be resolved into an inhibition by intracellular acidification and a CO2 effect independent of pHi change. Indeed a CO2 effect persisted despite using strongly buffered intracellular solutions abolishing any change in pHi, was present in TASK-2-K245A mutant insensitive to pHi, and also under carbonic anhydrase inhibition. The mechanism by which TASK-2 senses CO2 is unknown but requires the presence of the 245-273 stretch of amino acids in the C terminus that comprises numerous basic amino acids and is important in TASK-2 G protein subunit binding and regulation of the channel. The described CO2 effect might be of importance in the eventual roles played by TASK-2 in chemoreception in mouse and zebrafish.
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