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Yan R, Zhang P, Shen S, Zeng Y, Wang T, Chen Z, Ma W, Feng J, Suo C, Zhang T, Wei H, Jiang Z, Chen R, Li ST, Zhong X, Jia W, Sun L, Cang C, Zhang H, Gao P. Carnosine regulation of intracellular pH homeostasis promotes lysosome-dependent tumor immunoevasion. Nat Immunol 2024; 25:483-495. [PMID: 38177283 DOI: 10.1038/s41590-023-01719-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 11/28/2023] [Indexed: 01/06/2024]
Abstract
Tumor cells and surrounding immune cells undergo metabolic reprogramming, leading to an acidic tumor microenvironment. However, it is unclear how tumor cells adapt to this acidic stress during tumor progression. Here we show that carnosine, a mobile buffering metabolite that accumulates under hypoxia in tumor cells, regulates intracellular pH homeostasis and drives lysosome-dependent tumor immune evasion. A previously unrecognized isoform of carnosine synthase, CARNS2, promotes carnosine synthesis under hypoxia. Carnosine maintains intracellular pH (pHi) homeostasis by functioning as a mobile proton carrier to accelerate cytosolic H+ mobility and release, which in turn controls lysosomal subcellular distribution, acidification and activity. Furthermore, by maintaining lysosomal activity, carnosine facilitates nuclear transcription factor X-box binding 1 (NFX1) degradation, triggering galectin-9 and T-cell-mediated immune escape and tumorigenesis. These findings indicate an unconventional mechanism for pHi regulation in cancer cells and demonstrate how lysosome contributes to immune evasion, thus providing a basis for development of combined therapeutic strategies against hepatocellular carcinoma that exploit disrupted pHi homeostasis with immune checkpoint blockade.
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Affiliation(s)
- Ronghui Yan
- Anhui Key Laboratory of Hepatopancreatobiliary Surgery, Department of General Surgery, Anhui Provincial Hospital, the First Affiliated Hospital of USTC, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, China
- The Chinese Academy of Sciences Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, China
| | - Pinggen Zhang
- Anhui Key Laboratory of Hepatopancreatobiliary Surgery, Department of General Surgery, Anhui Provincial Hospital, the First Affiliated Hospital of USTC, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, China
- The Chinese Academy of Sciences Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, China
- Anhui Province Key Laboratory of Biomedical Aging Research, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, China
- Insitute of Health and Medicine, Hefei Comprehensive National Science Center, Hefei, China
| | - Shengqi Shen
- Medical Research Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, China
| | - Yu Zeng
- The Chinese Academy of Sciences Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, China
| | - Ting Wang
- Anhui Key Laboratory of Hepatopancreatobiliary Surgery, Department of General Surgery, Anhui Provincial Hospital, the First Affiliated Hospital of USTC, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, China
- The Chinese Academy of Sciences Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, China
| | - Zhaolin Chen
- Anhui Key Laboratory of Hepatopancreatobiliary Surgery, Department of General Surgery, Anhui Provincial Hospital, the First Affiliated Hospital of USTC, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, China
| | - Wenhao Ma
- Anhui Key Laboratory of Hepatopancreatobiliary Surgery, Department of General Surgery, Anhui Provincial Hospital, the First Affiliated Hospital of USTC, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, China
- The Chinese Academy of Sciences Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, China
| | - Junru Feng
- Anhui Key Laboratory of Hepatopancreatobiliary Surgery, Department of General Surgery, Anhui Provincial Hospital, the First Affiliated Hospital of USTC, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, China
- The Chinese Academy of Sciences Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, China
| | - Caixia Suo
- Medical Research Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, China
| | - Tong Zhang
- Medical Research Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, China
| | - Haoran Wei
- Medical Research Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, China
| | - Zetan Jiang
- Anhui Key Laboratory of Hepatopancreatobiliary Surgery, Department of General Surgery, Anhui Provincial Hospital, the First Affiliated Hospital of USTC, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, China
- The Chinese Academy of Sciences Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, China
| | - Rui Chen
- Medical Research Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, China
| | - Shi-Ting Li
- Medical Research Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, China
| | - Xiuying Zhong
- Medical Research Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, China
| | - Weidong Jia
- Anhui Key Laboratory of Hepatopancreatobiliary Surgery, Department of General Surgery, Anhui Provincial Hospital, the First Affiliated Hospital of USTC, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, China
| | - Linchong Sun
- Medical Research Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, China
| | - Chunlei Cang
- The Chinese Academy of Sciences Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, China
| | - Huafeng Zhang
- Anhui Key Laboratory of Hepatopancreatobiliary Surgery, Department of General Surgery, Anhui Provincial Hospital, the First Affiliated Hospital of USTC, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, China.
- The Chinese Academy of Sciences Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, China.
- Anhui Province Key Laboratory of Biomedical Aging Research, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, China.
- Insitute of Health and Medicine, Hefei Comprehensive National Science Center, Hefei, China.
| | - Ping Gao
- Medical Research Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, 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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Buxton RB. Thermodynamic limitations on brain oxygen metabolism: physiological implications. J Physiol 2024; 602:683-712. [PMID: 38349000 DOI: 10.1113/jp284358] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 01/03/2024] [Indexed: 02/20/2024] Open
Abstract
Recent thermodynamic modelling indicates that maintaining the brain tissue ratio of O2 to CO2 (abbreviated tissue O2 /CO2 ) is critical for preserving the entropy increase available from oxidative metabolism of glucose, with a fall of that available entropy leading to a reduction of the phosphorylation potential and impairment of brain energy metabolism. This provides a novel perspective for understanding physiological responses under different conditions in terms of preserving tissue O2 /CO2 . To enable estimation of tissue O2 /CO2 in the human brain, a detailed mathematical model of O2 and CO2 transport was developed, and applied to reported physiological responses to different challenges, asking: how well is tissue O2 /CO2 preserved? Reported experimental results for increased neural activity, hypercapnia and hypoxia due to high altitude are consistent with preserving tissue O2 /CO2 . The results highlight two physiological mechanisms that control tissue O2 /CO2 : cerebral blood flow, which modulates tissue O2 ; and ventilation rate, which modulates tissue CO2 . The hypoxia modelling focused on humans at high altitude, including acclimatized lowlanders and Tibetan and Andean adapted populations, with a primary finding that decreasing CO2 by increasing ventilation rate is more effective for preserving tissue O2 /CO2 than increasing blood haemoglobin content to maintain O2 delivery to tissue. This work focused on the function served by particular physiological responses, and the underlying mechanisms require further investigation. The modelling provides a new framework and perspective for understanding how blood flow and other physiological factors support energy metabolism in the brain under a wide range of conditions. KEY POINTS: Thermodynamic modelling indicates that preserving the O2 /CO2 ratio in brain tissue is critical for preserving the entropy change available from oxidative metabolism of glucose and the phosphorylation potential underlying energy metabolism. A detailed model of O2 and CO2 transport was developed to allow estimation of the tissue O2 /CO2 ratio in the human brain in different physiological states. Reported experimental results during hypoxia, hypercapnia and increased oxygen metabolic rate in response to increased neural activity are consistent with maintaining brain tissue O2 /CO2 ratio. The hypoxia modelling of high-altitude acclimatization and adaptation in humans demonstrates the critical role of reducing CO2 with increased ventilation for preserving tissue O2 /CO2 . Preservation of tissue O2 /CO2 provides a novel perspective for understanding the function of observed physiological responses under different conditions in terms of preserving brain energy metabolism, although the mechanisms underlying these functions are not well understood.
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Affiliation(s)
- Richard B Buxton
- Center for Functional Magnetic Resonance Imaging, Department of Radiology, University of California, San Diego, California, USA
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Ivanov IT, Paarvanova BK. Radiofrequency dielectric spectroscopy study: Effects of pH, hydrogen bond donors and acceptors on the attachment of spectrin skeleton to the lipid membrane of erythrocytes. Bioelectromagnetics 2024; 45:58-69. [PMID: 38013630 DOI: 10.1002/bem.22491] [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: 09/26/2022] [Revised: 10/07/2023] [Accepted: 11/02/2023] [Indexed: 11/29/2023]
Abstract
Band 3 protein and glycophorin C are the two major integral proteins of the lipid membrane of human red blood cells (RBCs). They are attached from below to a network of elastic filamentous spectrin, the third major RBC membrane protein. The binding properties of the attachments to spectrin affect the shape and deformability of RBCs. We addressed band 3 and glycophorin C attachments to spectrin by measuring the strength of two recently discovered radiofrequency dielectric relaxations, βsp (1.4 MHz) and γ1sp (9 MHz), that are observable as changes in the complex admittance of RBCs in medium. In medium at pH 5.2, and also in media with protic substances (formamide, methylformamide, or urea), the βsp relaxation became inhibited that is attributable to detachment of glycophorin C from spectrin. In medium at pH 9.2, we observed inhibition of γ1sp relaxation attributable to detachment of band 3 from spectrin, as also was seen in media with aprotic substances difluoropyridine, dimethylsolfoxide, dimethylformamide, acetone, sodium tetrakis(4-fluorophenyl)borate), chlorpromazine, thioridazine and trifluopiperazine. The viscogenic cosolvents (glycerol, ethylene glycol, or i-erythritol) inhibited both the βsp and γ1sp relaxations and significantly lowered their characteristic frequencies. Our observations indicate that the glycophorin C attachment to spectrin has nucleophilic centers whose saturation disconnects this attachment and inhibits the βsp relaxation, whereas at band 3-spectrin attachment site, it is the saturation of electrophilic centers that weakens this attachment and inhibits the γ1sp relaxation.
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Affiliation(s)
- Ivan T Ivanov
- Department of Physics, Biophysics, Roentgenology and Radiology, Medical Faculty, Thracian University, Stara Zagora, Bulgaria
| | - Boyana K Paarvanova
- Department of Physics, Biophysics, Roentgenology and Radiology, Medical Faculty, Thracian University, Stara Zagora, Bulgaria
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Ivanov IT, Paarvanova BK. Role of Plasma Membrane at Dielectric Relaxations and Intermembrane Interaction in Human Erythrocytes. MEMBRANES 2023; 13:658. [PMID: 37505024 PMCID: PMC10386205 DOI: 10.3390/membranes13070658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/05/2023] [Accepted: 07/07/2023] [Indexed: 07/29/2023]
Abstract
Dielectric relaxations at 1.4 MHz (βsp) and 9 MHz (γ1sp) on the erythrocyte spectrin network were studied by dielectric spectroscopy using dense suspensions of erythrocytes and erythrocyte ghost membranes, subjected to extraction with up to 0.2% volume Triton-X-100. The step-wise extraction of up to 60% of membrane lipids preserved γ1sp and gradually removed βsp-relaxation. On increasing the concentration up to 100 mM of NaCl at either side of erythrocyte plasma membranes, the βsp-relaxation was linearly enhanced, while the strength of γ1sp-relaxation remained unchanged. In media with NaCl between 100 and 150 mM βsp-relaxation became slightly inhibited, while γ1sp-relaxation almost disappeared, possibly due to the decreased electrostatic repulsion allowing erythrocytes to come into closer contact. When these media contained, at concentrations 10-30 mg/mL dextran (MW 7 kDa), polyethylene glycol or polyvinylpyrrolidone (40 kDa), or albumin or homologous plasma with equivalent concentration of albumin, the γ1sp-relaxation was about tenfold enhanced, while βsp-relaxation was strengthened or preserved. The results suggest the Maxwell-Vagner accumulation of ions on the lipid bilayer as an energy source for βsp-relaxation. While βsp-relaxation appears sensitive to erythrocyte membrane deformability, γ1sp-relaxation could be a sensitive marker for the inter-membrane interactions between erythrocytes.
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Affiliation(s)
- Ivan T Ivanov
- Department of Physics, Biophysics, Roentgenology and Radiology, Medical Faculty, Thracian University, 6000 Stara Zagora, Bulgaria
| | - Boyana K Paarvanova
- Department of Physics, Biophysics, Roentgenology and Radiology, Medical Faculty, Thracian University, 6000 Stara Zagora, Bulgaria
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Lew VL. The circulatory dynamics of human red blood cell homeostasis: Oxy-deoxy and PIEZO1-triggered changes. Biophys J 2023; 122:484-495. [PMID: 36588342 PMCID: PMC9941722 DOI: 10.1016/j.bpj.2022.12.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 11/14/2022] [Accepted: 12/30/2022] [Indexed: 01/02/2023] Open
Abstract
The vital function of red blood cells (RBCs) is to mediate the transport of oxygen from lungs to tissues and of CO2 from tissues to lungs. The gas exchanges occur during capillary transits within fractions of a second. Each oxygenation-deoxygenation and deoxygenation-reoxygenation transition on hemoglobin triggers sharp changes in RBC pH, leading to downstream changes in ion fluxes, membrane potential, and cell volume. The dynamics of these changes during the variable periods between capillary transits in vivo remains a mystery inaccessible to study by current methodologies, a knowledge gap on a fundamental physiological process that is the focus of the present study. The use of a computational model of human RBC homeostasis of tested accreditation enabled a detailed investigation of the expected RBC changes during intercapillary transits, with results advancing novel insights and predictions. The predicted rates of relative RBC volume change on oxygenation-deoxygenation (oxy-deoxy) and deoxygenation-reoxygenation transitions were about 1.5%/min and -0.9%/min, respectively, far too slow to allow the cells to reach steady states in the intervals between capillary transits. The amplitude of the oxy-deoxy-reoxygenation volume fluctuations varied in proportion with the duration of the intercapillary transit intervals. Upon capillary entry, oxy-deoxy-induced changes occur concurrently with deformation-induced PIEZO1 channel activation, both processes affecting cell pH, membrane potential, and cell volume during intertransit periods. The model showed that the effects were strictly additive as expected from processes operating independently on the cell's homeostatic fabric. Analysis of the mechanisms behind these predictions revealed, for the first time, the complex interactions between oxy-deoxy and ion transport processes that ensure the long-term homeostatic stability of RBCs for optimal gas transport in physiological conditions and how these may become altered in diseased states. Possible designs of microfluidic devices to test the model predictions are discussed.
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Affiliation(s)
- Virgilio L Lew
- Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Site, Cambridge, United Kingdom.
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Haag M, Kehrer J, Sanchez CP, Deponte M, Lanzer M. Physiological jump in erythrocyte redox potential during Plasmodium falciparum development occurs independent of the sickle cell trait. Redox Biol 2022; 58:102536. [DOI: 10.1016/j.redox.2022.102536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 10/26/2022] [Accepted: 11/08/2022] [Indexed: 11/11/2022] Open
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Ring T, Rees SE, Frische S. Acid content and buffer-capacity: a charge-balance perspective. Scand J Clin Lab Invest 2022; 82:356-362. [PMID: 35792720 DOI: 10.1080/00365513.2022.2092903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Rational treatment and thorough diagnostic classification of acid-base disorders requires quantitative understanding of the mechanisms that generate and dissipate loads of acid and base. A natural precondition for this tallying is the ability to quantify the acid content in any specified fluid. Physical chemistry defines the pH-dependent charge on any buffer species, and also on strong ions on which, by definition, the charge is pH-invariant. Based, then, on the requirement of electroneutrality and conservation of mass, it was shown in 1914 that pH can be calculated and understood on the basis of the chemical composition of any fluid. Herein we first show that this specification for [H+] of the charge-balance model directly delivers the pH-dependent buffer-capacity as defined in the literature. Next, we show how the notion of acid transport as proposed in experimental physiology can be understood as a change in strong ion difference, ΔSID. Finally, based on Brønsted-Lowry theory we demonstrate that by defining the acid content as titratable acidity, this is equal to SIDref - SID, where SIDref is SID at pH 7.4. Thereby, any chemical situation is represented as a curve in a novel diagram with titratable acidity = SIDref - SID as a function of pH. For any specification of buffer chemistry, therefore, the change in acid content in the fluid is path invariant. Since constituents of SID and titratable acidity are additive, we thereby, based on first principles, have defined a new framework for modeling acid balance across a cell, a whole organ, or the whole-body.
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Affiliation(s)
- Troels Ring
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Stephen Edward Rees
- Respiratory and Critical Care Group, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
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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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Posen AK, Paloucek FP, Gimbar RP. Anion gap physiology and faults of the correction formula. Am J Health Syst Pharm 2021; 79:446-451. [PMID: 34788391 DOI: 10.1093/ajhp/zxab423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
DISCLAIMER In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. PURPOSE The anion gap is a calculated fundamental laboratory parameter used to identify and monitor acid-base disturbances. A recently popularized correction formula transforms the resulting integer to compensate for hypoalbuminemia and improve diagnostic yield. Clinical pharmacists should be aware of the underlying biochemistry, interpretation, and limitations of this formula to discern drug- and disease-related etiologies. SUMMARY The anion gap is utilized in most care settings, ranging from outpatient monitoring to inpatient intensive care units. Supported by decades of experience, the original anion gap derives its value from its simplicity. Applying the anion gap in metabolic acidosis can help narrow differential diagnosis and detect concomitant acid-base disorders. To account for hypoalbuminemia and potential missed diagnoses, a correction formula was developed to improve sensitivity. Yet, the law of electroneutrality ensures that hypoalbuminemia is already accounted for in the original anion gap, and the proposed correction formula was derived from samples unrepresentative of human physiology. Evidence from clinical trials shows no benefit from applying the correction formula. CONCLUSION There is no advantage to correcting the anion gap, and such correction may increase the risk of misinterpretation or error. Clinicians should understand these limitations when diagnosing or trending acid-base disturbances.
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Affiliation(s)
- Andrew K Posen
- Department of Pharmacy Practice, University of Illinois at Chicago College of Pharmacy, Chicago, IL, USA
| | - Frank P Paloucek
- Department of Pharmacy Practice, University of Illinois at Chicago College of Pharmacy, Chicago, IL, USA
| | - Renee Petzel Gimbar
- Department of Pharmacy Practice, University of Illinois at Chicago College of Pharmacy, Chicago, IL, USA
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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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Yoon MC, Solania A, Jiang Z, Christy MP, Podvin S, Mosier C, Lietz CB, Ito G, Gerwick WH, Wolan DW, Hook G, O’Donoghue AJ, Hook V. Selective Neutral pH Inhibitor of Cathepsin B Designed Based on Cleavage Preferences at Cytosolic and Lysosomal pH Conditions. ACS Chem Biol 2021; 16:1628-1643. [PMID: 34416110 DOI: 10.1021/acschembio.1c00138] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Cathepsin B is a cysteine protease that normally functions within acidic lysosomes for protein degradation, but in numerous human diseases, cathepsin B translocates to the cytosol having neutral pH where the enzyme activates inflammation and cell death. Cathepsin B is active at both the neutral pH 7.2 of the cytosol and the acidic pH 4.6 within lysosomes. We evaluated the hypothesis that cathepsin B may possess pH-dependent cleavage preferences that can be utilized for design of a selective neutral pH inhibitor by (1) analysis of differential cathepsin B cleavage profiles at neutral pH compared to acidic pH using multiplex substrate profiling by mass spectrometry (MSP-MS), (2) design of pH-selective peptide-7-amino-4-methylcoumarin (AMC) substrates, and (3) design and validation of Z-Arg-Lys-acyloxymethyl ketone (AOMK) as a selective neutral pH inhibitor. Cathepsin B displayed preferences for cleaving peptides with Arg in the P2 position at pH 7.2 and Glu in the P2 position at pH 4.6, represented by its primary dipeptidyl carboxypeptidase and modest endopeptidase activity. These properties led to design of the substrate Z-Arg-Lys-AMC having neutral pH selectivity, and its modification with the AOMK warhead to result in the inhibitor Z-Arg-Lys-AOMK. This irreversible inhibitor displays nanomolar potency with 100-fold selectivity for inhibition of cathepsin B at pH 7.2 compared to pH 4.6, shows specificity for cathepsin B over other cysteine cathepsins, and is cell permeable and inhibits intracellular cathepsin B. These findings demonstrate that cathepsin B possesses pH-dependent cleavage properties that can lead to development of a potent, neutral pH inhibitor of this enzyme.
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Affiliation(s)
- Michael C. Yoon
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, California 92093, United States
| | - Angelo Solania
- Departments of Molecular Medicine and Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Zhenze Jiang
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Mitchell P. Christy
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093, United States
| | - Sonia Podvin
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Charles Mosier
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Christopher B. Lietz
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Gen Ito
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - William H. Gerwick
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093, United States
| | - Dennis W. Wolan
- Departments of Molecular Medicine and Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Gregory Hook
- American Life Sciences Pharmaceuticals, Inc., La Jolla, California 92037, United States
| | - Anthony J. O’Donoghue
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Vivian Hook
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
- Department of Neurosciences, School of Medicine, University of California, San Diego, La Jolla, California 92037, United States
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Phelan DE, Mota C, Lai C, Kierans SJ, Cummins EP. Carbon dioxide-dependent signal transduction in mammalian systems. Interface Focus 2021; 11:20200033. [PMID: 33633832 PMCID: PMC7898142 DOI: 10.1098/rsfs.2020.0033] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2020] [Indexed: 12/15/2022] Open
Abstract
Carbon dioxide (CO2) is a fundamental physiological gas known to profoundly influence the behaviour and health of millions of species within the plant and animal kingdoms in particular. A recent Royal Society meeting on the topic of 'Carbon dioxide detection in biological systems' was extremely revealing in terms of the multitude of roles that different levels of CO2 play in influencing plants and animals alike. While outstanding research has been performed by leading researchers in the area of plant biology, neuronal sensing, cell signalling, gas transport, inflammation, lung function and clinical medicine, there is still much to be learned about CO2-dependent sensing and signalling. Notably, while several key signal transduction pathways and nodes of activity have been identified in plants and animals respectively, the precise wiring and sensitivity of these pathways to CO2 remains to be fully elucidated. In this article, we will give an overview of the literature relating to CO2-dependent signal transduction in mammalian systems. We will highlight the main signal transduction hubs through which CO2-dependent signalling is elicited with a view to better understanding the complex physiological response to CO2 in mammalian systems. The main topics of discussion in this article relate to how changes in CO2 influence cellular function through modulation of signal transduction networks influenced by pH, mitochondrial function, adenylate cyclase, calcium, transcriptional regulators, the adenosine monophosphate-activated protein kinase pathway and direct CO2-dependent protein modifications. While each of these topics will be discussed independently, there is evidence of significant cross-talk between these signal transduction pathways as they respond to changes in CO2. In considering these core hubs of CO2-dependent signal transduction, we hope to delineate common elements and identify areas in which future research could be best directed.
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Affiliation(s)
- D. E. Phelan
- School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - C. Mota
- School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - C. Lai
- School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - S. J. Kierans
- School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - E. P. Cummins
- School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
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14
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PIEZO1 and the mechanism of the long circulatory longevity of human red blood cells. PLoS Comput Biol 2021; 17:e1008496. [PMID: 33690597 PMCID: PMC7946313 DOI: 10.1371/journal.pcbi.1008496] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 11/06/2020] [Indexed: 01/16/2023] Open
Abstract
Human red blood cells (RBCs) have a circulatory lifespan of about four months. Under constant oxidative and mechanical stress, but devoid of organelles and deprived of biosynthetic capacity for protein renewal, RBCs undergo substantial homeostatic changes, progressive densification followed by late density reversal among others, changes assumed to have been harnessed by evolution to sustain the rheological competence of the RBCs for as long as possible. The unknown mechanisms by which this is achieved are the subject of this investigation. Each RBC traverses capillaries between 1000 and 2000 times per day, roughly one transit per minute. A dedicated Lifespan model of RBC homeostasis was developed as an extension of the RCM introduced in the previous paper to explore the cumulative patterns predicted for repetitive capillary transits over a standardized lifespan period of 120 days, using experimental data to constrain the range of acceptable model outcomes. Capillary transits were simulated by periods of elevated cell/medium volume ratios and by transient deformation-induced permeability changes attributed to PIEZO1 channel mediation as outlined in the previous paper. The first unexpected finding was that quantal density changes generated during single capillary transits cease accumulating after a few days and cannot account for the observed progressive densification of RBCs on their own, thus ruling out the quantal hypothesis. The second unexpected finding was that the documented patterns of RBC densification and late reversal could only be emulated by the implementation of a strict time-course of decay in the activities of the calcium and Na/K pumps, suggestive of a selective mechanism enabling the extended longevity of RBCs. The densification pattern over most of the circulatory lifespan was determined by calcium pump decay whereas late density reversal was shaped by the pattern of Na/K pump decay. A third finding was that both quantal changes and pump-decay regimes were necessary to account for the documented lifespan pattern, neither sufficient on their own. A fourth new finding revealed that RBCs exposed to levels of PIEZO1-medited calcium permeation above certain thresholds in the circulation could develop a pattern of early or late hyperdense collapse followed by delayed density reversal. When tested over much reduced lifespan periods the results reproduced the known circulatory fate of irreversible sickle cells, the cell subpopulation responsible for vaso-occlusion and for most of the clinical manifestations of sickle cell disease. Analysis of the results provided an insightful new understanding of the mechanisms driving the changes in RBC homeostasis during circulatory aging in health and disease. The average circulatory lifespan of human red blood cells is about four months, amounting to about 200000 capillary transits. Among the many documented age-related changes red cells experience during this long sojourn the most relevant to homeostasis control comprise progressive densification with late density reversal, decline in the activities of calcium and sodium-potassium pumps, and slow inverse changes in their original sodium and potassium contents. Early experimental results have long established the view that these changes result from the cumulative effects of myriad capillary transits. However, many aspects of this process remain inaccessible to in vivo investigation. This prompted us to attempt a modelling approach applying a dedicated extension to our original red cell model. The results relegated the cumulative mechanism to a secondary role and exposed surprising critical roles for the declining patterns of the calcium and sodium-potassium pumps, as if harnessed by evolution to extend the circulatory longevity of cells within volume ranges that enable optimal rheological performance. The mechanism the model revealed implicated complex interactions between PIEZO1, the calcium-activated potassium channel KCNN4, the anion exchanger AE1, and the calcium and sodium-potassium pumps. These studies proved the model potential for exploring red cell homeostasis in health and disease.
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15
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Oxaliplatin-induced neuropathy occurs through impairment of haemoglobin proton buffering and is reversed by carbonic anhydrase inhibitors. Pain 2021; 161:405-415. [PMID: 31634341 DOI: 10.1097/j.pain.0000000000001722] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Oxaliplatin is a cornerstone chemotherapeutic used in the treatment of colorectal cancer, the third leading cause of death in Western countries. Most side effects of this platinum-containing drug are adequately managed in the clinic, although acute and long-term neurotoxicity still severely compromises the quality of life of patients treated with oxaliplatin. We have previously demonstrated that therapeutically relevant concentrations/doses of oxaliplatin lead to a reduction in intracellular pH in mouse dorsal root ganglion (DRG) neurons in vitro and in vivo and that this alteration sensitizes TRPA1 and TRPV1 channels, which most likely mediate the allodynia associated with treatment. In this study, we show that oxaliplatin leads to a reduction of intracellular pH by forming adducts with neuronal haemoglobin, which acts in this setting as a proton buffer. Furthermore, we show that FDA-approved drugs that inhibit carbonic anhydrase (an enzyme that is linked to haemoglobin in intracellular pH homeostasis), ie, topiramate and acetazolamide, revert (1) oxaliplatin-induced cytosolic acidification and TRPA1 and TRPV1 modulation in DRG neurons in culture, (2) oxaliplatin-induced cytosolic acidification of DRG of treated animals, and (3) oxaliplatin-induced acute cold allodynia in mice while not affecting OHP-induced cytotoxicity on cancer cells. Our data would therefore suggest that reversal of oxaliplatin-induced cytosolic acidification is a viable strategy to minimize acute oxaliplatin-induced symptoms.
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16
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Single-cell O 2 exchange imaging shows that cytoplasmic diffusion is a dominant barrier to efficient gas transport in red blood cells. Proc Natl Acad Sci U S A 2020; 117:10067-10078. [PMID: 32321831 PMCID: PMC7211990 DOI: 10.1073/pnas.1916641117] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Blood is routinely tested for gas-carrying capacity (total hemoglobin), but this cannot determine the speed at which red blood cells (RBCs) exchange gases. Such information is critical for evaluating the physiological fitness of RBCs, which have very limited capillary transit times (<1 s) for turning over substantial volumes of gas. We developed a method to quantify gas exchange in individual RBCs and used it to show that restricted diffusion, imposed by hemoglobin crowding, is a major barrier to gas flows. Consequently, hematological disorders manifesting a change in cell shape or hemoglobin concentration have uncharted implications on gas exchange, which we illustrate using inherited anemias. With its single-cell resolution, the method can identify physiologically inferior subpopulations, providing a clinically useful appraisal of blood quality. Disorders of oxygen transport are commonly attributed to inadequate carrying capacity (anemia) but may also relate to inefficient gas exchange by red blood cells (RBCs), a process that is poorly characterized yet assumed to be rapid. Without direct measurements of gas exchange at the single-cell level, the barriers to O2 transport and their relationship with hematological disorders remain ill defined. We developed a method to track the flow of O2 in individual RBCs by combining ultrarapid solution switching (to manipulate gas tension) with single-cell O2 saturation fluorescence microscopy. O2 unloading from RBCs was considerably slower than previously estimated in acellular hemoglobin solutions, indicating the presence of diffusional barriers in intact cells. Rate-limiting diffusion across cytoplasm was demonstrated by osmotically induced changes to hemoglobin concentration (i.e., diffusive tortuosity) and cell size (i.e., diffusion pathlength) and by comparing wild-type cells with hemoglobin H (HbH) thalassemia (shorter pathlength and reduced tortuosity) and hereditary spherocytosis (HS; expanded pathlength). Analysis of the distribution of O2 unloading rates in HS RBCs identified a subpopulation of spherocytes with greatly impaired gas exchange. Tortuosity imposed by hemoglobin was verified by demonstrating restricted diffusivity of CO2, an acidic gas, from the dissipative spread of photolytically uncaged H+ ions across cytoplasm. Our findings indicate that cytoplasmic diffusion, determined by pathlength and tortuosity, is a major barrier to efficient gas handling by RBCs. Consequently, changes in RBC shape and hemoglobin concentration, which are common manifestations of hematological disorders, can have hitherto unrecognized and clinically significant implications on gas exchange.
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17
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Hook V, Yoon M, Mosier C, Ito G, Podvin S, Head BP, Rissman R, O'Donoghue AJ, Hook G. Cathepsin B in neurodegeneration of Alzheimer's disease, traumatic brain injury, and related brain disorders. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1868:140428. [PMID: 32305689 DOI: 10.1016/j.bbapap.2020.140428] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 03/31/2020] [Accepted: 04/08/2020] [Indexed: 12/21/2022]
Abstract
Investigations of Alzheimer's disease (AD), traumatic brain injury (TBI), and related brain disorders have provided extensive evidence for involvement of cathepsin B, a lysosomal cysteine protease, in mediating the behavioral deficits and neuropathology of these neurodegenerative diseases. This review integrates findings of cathepsin B regulation in clinical biomarker studies, animal model genetic and inhibitor evaluations, structural studies, and lysosomal cell biological mechanisms in AD, TBI, and related brain disorders. The results together indicate the role of cathepsin B in the behavioral deficits and neuropathology of these disorders. Lysosomal leakage occurs in AD and TBI, and related neurodegeneration, which leads to the hypothesis that cathepsin B is redistributed from the lysosome to the cytosol where it initiates cell death and inflammation processes associated with neurodegeneration. These results together implicate cathepsin B as a major contributor to these neuropathological changes and behavioral deficits. These findings support the investigation of cathepsin B as a potential drug target for therapeutic discovery and treatment of AD, TBI, and TBI-related brain disorders.
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Affiliation(s)
- Vivian Hook
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States of America; Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA, United States of America; Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, United States of America.
| | - Michael Yoon
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States of America; Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA, United States of America
| | - Charles Mosier
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States of America
| | - Gen Ito
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States of America
| | - Sonia Podvin
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States of America
| | - Brian P Head
- VA San Diego Healthcare System, La Jolla, CA, United States of America; Department of Anesthesia, University of California San Diego, La Jolla, CA, United States of America
| | - Robert Rissman
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, United States of America; VA San Diego Healthcare System, La Jolla, CA, United States of America
| | - Anthony J O'Donoghue
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States of America
| | - Gregory Hook
- American Life Sciences Pharmaceuticals, Inc., La Jolla, CA, United States of America
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18
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Mindukshev IV, Sudnitsyna JS, Skverchinskaya EA, Andreyeva AY, Dobrylko IA, Senchenkova EY, Krivchenko AI, Gambaryan SP. Erythrocytes’ Reactions to Osmotic, Ammonium, and Oxidative Stress Are Inhibited under Hypoxia. BIOCHEMISTRY (MOSCOW), SUPPLEMENT SERIES A: MEMBRANE AND CELL BIOLOGY 2020. [DOI: 10.1134/s1990747819040081] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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19
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Yastrebova ES, Konokhova AI, Strokotov DI, Karpenko AA, Maltsev VP, Chernyshev AV. Proposed Dynamics of CDB3 Activation in Human Erythrocytes by Nifedipine Studied with Scanning Flow Cytometry. Cytometry A 2019; 95:1275-1284. [PMID: 31750613 DOI: 10.1002/cyto.a.23918] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 09/25/2019] [Accepted: 10/01/2019] [Indexed: 12/16/2022]
Abstract
Nifedipine is calcium channels and pumps blocker widely used in medicine. However, mechanisms of nifedipine action in blood are not clear. In particular, the influence of nifedipine on erythrocytes is far from completely understood. In this work, applying scanning flow cytometry, we observed experimentally for the first time the dynamics behind a significant increase of HCO3 - /Cl- transmembrane exchange rate of CDB3 (main anion exchanger, AE1, Band 3, SLC4A1) of human erythrocytes in the presence of nifedipine in blood. It was found that the rate of CDB3 activation is not limited by the rate of nifedipine binding and/or Ca2+ transport. In order to explain the experimental data, we suggested a kinetic model assuming that the rate of CDB3 activation is limited by the dynamics of the balance between two intracellular processes (1) the activation of CDB3 limited by its interaction with intracellular Ca2+ , and (2) the spontaneous deactivation of CDB3. Thus the use of scanning flow cytometry allowed to clarify quantitatively the molecular kinetic mechanism of nifedipine action on human erythrocytes. In particular, the efficiency (~30) and rates of activation (~0.3 min-1 ) and deactivation (~10-3 min-1 ) of CDB3 in human erythrocytes was evaluated for two donors. © 2019 International Society for Advancement of Cytometry.
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Affiliation(s)
- Ekaterina S Yastrebova
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya 3, Novosibirsk, 630090, Russia.,Novosibirsk State University, Pirogova 2, Novosibirsk, 630090, Russia.,Meshalkin National Medical Research Center, Ministry of Health of Russian Federation, Rechkunovskaya 15, 630055, Novosibirsk, Russia
| | - Anastasiya I Konokhova
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya 3, Novosibirsk, 630090, Russia.,Meshalkin National Medical Research Center, Ministry of Health of Russian Federation, Rechkunovskaya 15, 630055, Novosibirsk, Russia
| | - Dmitry I Strokotov
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya 3, Novosibirsk, 630090, Russia.,Novosibirsk State Medical University, Krasny Prospect 52, Novosibirsk, 630091, Russia
| | - Andrei A Karpenko
- Meshalkin National Medical Research Center, Ministry of Health of Russian Federation, Rechkunovskaya 15, 630055, Novosibirsk, Russia
| | - Valeri P Maltsev
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya 3, Novosibirsk, 630090, Russia.,Novosibirsk State University, Pirogova 2, Novosibirsk, 630090, Russia.,Novosibirsk State Medical University, Krasny Prospect 52, Novosibirsk, 630091, Russia
| | - Andrei V Chernyshev
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya 3, Novosibirsk, 630090, Russia.,Novosibirsk State University, Pirogova 2, Novosibirsk, 630090, Russia
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20
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Solheim SA, Bejder J, Breenfeldt Andersen A, Mørkeberg J, Nordsborg NB. Autologous Blood Transfusion Enhances Exercise Performance-Strength of the Evidence and Physiological Mechanisms. SPORTS MEDICINE-OPEN 2019; 5:30. [PMID: 31286284 PMCID: PMC6614299 DOI: 10.1186/s40798-019-0204-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 06/25/2019] [Indexed: 01/21/2023]
Abstract
This review critically evaluates the magnitude of performance enhancement that can be expected from various autologous blood transfusion (ABT) procedures and the underlying physiological mechanisms. The review is based on a systematic search, and it was reported that 4 of 28 studies can be considered of very high quality, i.e. placebo-controlled, double-blind crossover studies. However, both high-quality studies and other studies have generally reported performance-enhancing effects of ABT on exercise intensities ranging from ~70 to 100% of absolute peak oxygen uptake (VO2peak) with durations of 5–45 min, and the effect was also seen in well-trained athletes. A linear relationship exists between ABT volume and change in VO2peak. The likely correlation between ABT volume and endurance performance was not evident in the few available studies, but reinfusion of as little as 135 mL packed red blood cells has been shown to increase time trial performance. Red blood cell reinfusion increases endurance performance by elevating arterial oxygen content (CaO2). The increased CaO2 is accompanied by reduced lactate concentrations at submaximal intensities as well as increased VO2peak. Both effects improve endurance performance. Apparently, the magnitude of change in haemoglobin concentration ([Hb]) explains the increase in VO2peak associated with ABT because blood volume and maximal cardiac output have remained constant in the majority of ABT studies. Thus, the arterial-venous O2 difference during exercise must be increased after reinfusion, which is supported by experimental evidence. Additionally, it remains a possibility that ABT can enhance repeated sprint performance, but studies on this topic are lacking. The only available study did not reveal a performance-enhancing effect of reinfusion on 4 × 30 s sprinting. The reviewed studies are of importance for both the physiological understanding of how ABT interacts with exercise capacity and in relation to anti-doping efforts. From an anti-doping perspective, the literature review demonstrates the need for methods to detect even small ABT volumes.
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Affiliation(s)
- Sara Amalie Solheim
- Department of Nutrition, Exercise and Sport Sciences, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen, Denmark.,Anti Doping Denmark, Brøndby, Denmark
| | - Jacob Bejder
- Department of Nutrition, Exercise and Sport Sciences, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen, Denmark
| | - Andreas Breenfeldt Andersen
- Department of Nutrition, Exercise and Sport Sciences, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen, Denmark
| | | | - Nikolai Baastrup Nordsborg
- Department of Nutrition, Exercise and Sport Sciences, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen, Denmark.
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21
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Hamzeh H, Alvarez L, Strünker T, Kierzek M, Brenker C, Deal PE, Miller EW, Seifert R, Kaupp UB. Kinetic and photonic techniques to study chemotactic signaling in sea urchin sperm. Methods Cell Biol 2019; 151:487-517. [PMID: 30948028 DOI: 10.1016/bs.mcb.2018.12.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Sperm from sea urchins are attracted by chemical cues released by the egg-a mechanism called chemotaxis. We describe here the signaling pathway and molecular components endowing sperm with single-molecule sensitivity. Chemotactic signaling and behavioral responses occur on a timescale of a few milliseconds to seconds. We describe the techniques and chemical tools used to resolve the signaling events in time. The techniques include rapid-mixing devices, rapid stroboscopic microscopy, and photolysis of caged second messengers and chemoattractants.
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Affiliation(s)
- Hussein Hamzeh
- Department of Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Bonn, Germany
| | - Luis Alvarez
- Department of Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Bonn, Germany
| | - Timo Strünker
- Center of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Münster, Germany
| | - Michelina Kierzek
- Center of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Münster, Germany
| | - Christoph Brenker
- Center of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Münster, Germany
| | - Parker E Deal
- Department of Chemistry, University of California, Berkeley, CA, United States
| | - Evan W Miller
- Department of Chemistry, University of California, Berkeley, CA, United States; Department of Molecular & Cell Biology, University of California, Berkeley, CA, United States; Helen Wills Neuroscience Institute, University of California, Berkeley, CA, United States
| | - Reinhard Seifert
- Department of Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Bonn, Germany
| | - U Benjamin Kaupp
- Department of Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Bonn, Germany.
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22
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Xiong Y, Xiong Y, Wang Y, Zhao Y, Li Y, Ren Y, Wang R, Zhao M, Hao Y, Liu H, Wang X. Exhaustive-exercise-induced oxidative stress alteration of erythrocyte oxygen release capacity. Can J Physiol Pharmacol 2018; 96:953-962. [DOI: 10.1139/cjpp-2017-0691] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The aim of the present study was to explore the effect of exhaustive running exercise in the oxygen release capacity of rat erythrocytes. Rats were divided into sedentary control, moderate running exercise, and exhaustive running exercise groups. The thermodynamic and kinetic properties of the erythrocyte oxygen release process of the different groups were tested. We also determined the degree of band-3 oxidation and phosphorylation, anion transport activity, and carbonic anhydrase isoform II activity. Biochemical studies suggested that exhaustive running significantly increased oxidative injury parameters in thiobarbituric acid reactive substances and methaemoglobin levels. Furthermore, exhaustive running significantly decreased anion transport activity and carbonic anhydrase isoform II activity. Thermodynamic analysis indicated that erythrocytes oxygen release ability also significantly increased due to elevated 2,3-DPG level after exhaustive running. Kinetic analysis indicated that exhaustive running resulted in significantly decreased T50 value. We presented evidence that exhaustive running remarkably impacted thermodynamic and kinetic properties of RBC oxygen release. In addition, changes in 2,3-DPG levels and band-3 oxidation and phosphorylation could be the driving force for exhaustive-running-induced alterations in erythrocyte oxygen release thermodynamic and kinetic properties.
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Affiliation(s)
- Yanlian Xiong
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, Chongqing 400030, P.R. China
- Department of Anatomy, School of Basic Medicine, Binzhou Medical University, Yantai, P.R. China
| | - Yanlei Xiong
- Department of Pathophysiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences (CAMS), School of Basic Medicine, Peking Union Medical College, Beijing (PUMC), P.R. China
| | - Yueming Wang
- Department of Anatomy, School of Basic Medicine, Binzhou Medical University, Yantai, P.R. China
| | - Yajin Zhao
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, Chongqing 400030, P.R. China
| | - Yaojin Li
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, Chongqing 400030, P.R. China
| | - Yang Ren
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, Chongqing 400030, P.R. China
| | - Ruofeng Wang
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, Chongqing 400030, P.R. China
| | - Mingzi Zhao
- Department of Anatomy, School of Basic Medicine, Binzhou Medical University, Yantai, P.R. China
| | - Yitong Hao
- Department of Anatomy, School of Basic Medicine, Binzhou Medical University, Yantai, P.R. China
| | - Haibei Liu
- Department of Anatomy, School of Basic Medicine, Binzhou Medical University, Yantai, P.R. China
| | - Xiang Wang
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, Chongqing 400030, P.R. China
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23
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Windler F, Bönigk W, Körschen HG, Grahn E, Strünker T, Seifert R, Kaupp UB. The solute carrier SLC9C1 is a Na +/H +-exchanger gated by an S4-type voltage-sensor and cyclic-nucleotide binding. Nat Commun 2018; 9:2809. [PMID: 30022052 PMCID: PMC6052114 DOI: 10.1038/s41467-018-05253-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 06/15/2018] [Indexed: 11/30/2022] Open
Abstract
Voltage-sensing (VSD) and cyclic nucleotide-binding domains (CNBD) gate ion channels for rapid electrical signaling. By contrast, solute carriers (SLCs) that passively redistribute substrates are gated by their substrates themselves. Here, we study the orphan sperm-specific solute carriers SLC9C1 that feature a unique tripartite structure: an exchanger domain, a VSD, and a CNBD. Voltage-clamp fluorimetry shows that SLC9C1 is a genuine Na+/H+ exchanger gated by voltage. The cellular messenger cAMP shifts the voltage range of activation. Mutations in the transport domain, the VSD, or the CNBD strongly affect Na+/H+ exchange, voltage gating, or cAMP sensitivity, respectively. Our results establish SLC9C1 as a phylogenetic chimaera that combines the ion-exchange mechanism of solute carriers with the gating mechanism of ion channels. Classic SLCs slowly readjust changes in the intra- and extracellular milieu, whereas voltage gating endows the Na+/H+ exchanger with the ability to produce a rapid pH response that enables downstream signaling events. The sperm-specific solute carrier SLC9C1 is a phylogenetic chimaera that carries a voltage-sensing (VSD) and a cyclic nucleotide-binding domain (CNBD). Here authors show by electrophysiology and fluorimetry that SLC9C1 is a genuine Na+/H+ exchanger gated by voltage and cAMP.
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Affiliation(s)
- F Windler
- Center of Advanced European Studies and Research (caesar), Department Molecular Sensory Systems, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany.,Marine Biological Laboratory, 7 MBL Street, Woods Hole, 02543, MA, USA
| | - W Bönigk
- Center of Advanced European Studies and Research (caesar), Department Molecular Sensory Systems, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany
| | - H G Körschen
- Center of Advanced European Studies and Research (caesar), Department Molecular Sensory Systems, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany
| | - E Grahn
- Center of Advanced European Studies and Research (caesar), Department Molecular Sensory Systems, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany
| | - T Strünker
- Center of Advanced European Studies and Research (caesar), Department Molecular Sensory Systems, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany.,Marine Biological Laboratory, 7 MBL Street, Woods Hole, 02543, MA, USA.,University Hospital Münster, Center of Reproductive Medicine and Andrology, Albert-Schweitzer-Campus 1, Geb. D11, 48149, Münster, Germany
| | - R Seifert
- Center of Advanced European Studies and Research (caesar), Department Molecular Sensory Systems, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany. .,Marine Biological Laboratory, 7 MBL Street, Woods Hole, 02543, MA, USA.
| | - U B Kaupp
- Center of Advanced European Studies and Research (caesar), Department Molecular Sensory Systems, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany. .,Marine Biological Laboratory, 7 MBL Street, Woods Hole, 02543, MA, USA. .,University of Bonn, Life & Medical Sciences Institute (LIMES), Carl-Troll-Str. 31, 53115, Bonn, Germany.
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24
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Ueha T, Oe K, Miwa M, Hasegawa T, Koh A, Nishimoto H, Lee SY, Niikura T, Kurosaka M, Kuroda R, Sakai Y. Increase in carbon dioxide accelerates the performance of endurance exercise in rats. J Physiol Sci 2018; 68:463-470. [PMID: 28601950 PMCID: PMC10717130 DOI: 10.1007/s12576-017-0548-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 05/31/2017] [Indexed: 01/15/2023]
Abstract
Endurance exercise generates CO2 via aerobic metabolism; however, its role remains unclear. Exogenous CO2 by transcutaneous delivery promotes muscle fibre-type switching to increase endurance power in skeletal muscles. Here we determined the performance of rats running in activity wheels with/without transcutaneous CO2 exposure to clarify its effect on endurance exercise and recovery from muscle fatigue. Rats were randomised to control, training and CO2 groups. Endurance exercise included activity-wheel running with/without transcutaneous CO2 delivery. Running performance was measured after exercise initiation. We also analysed changes in muscle weight and muscle fibres in the tibialis anterior muscle. Running performance improved over the treatment period in the CO2 group, with a concomitant switch in muscle fibres to slow-type. The mitochondrial DNA content and capillary density in the CO2 group increased. CO2 was beneficial for performance and muscle development during endurance exercise: it may enhance recovery from fatigue and support anabolic metabolism in skeletal muscles.
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Affiliation(s)
- Takeshi Ueha
- Division of Rehabilitation Medicine, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
- NeoChemir Inc, Kobe, Japan
| | - Keisuke Oe
- Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
- Department of Orthopaedic Surgery, Hyogo Prefectural Awaji Hospital, Awaji, Japan
| | - Masahiko Miwa
- Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Takumi Hasegawa
- Department of Oral and Maxillofacial Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Akihiro Koh
- Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hanako Nishimoto
- Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Sang Yang Lee
- Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Takahiro Niikura
- Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Masahiro Kurosaka
- Division of Rehabilitation Medicine, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
- Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Ryosuke Kuroda
- Division of Rehabilitation Medicine, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
- Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yoshitada Sakai
- Division of Rehabilitation Medicine, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
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25
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Rahimi N, Abdolghaffari AH, Partoazar A, Javadian N, Dehpour T, Mani AR, Dehpour AR. Fresh red blood cells transfusion protects against aluminum phosphide-induced metabolic acidosis and mortality in rats. PLoS One 2018; 13:e0193991. [PMID: 29590163 PMCID: PMC5874013 DOI: 10.1371/journal.pone.0193991] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 02/22/2018] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Aluminum phosphide (AlP) is used as pesticide in some countries for protection of stored grains. Human poisoning with AlP due to suicide attempt or accidental environmental exposure is associated with very high mortality partially due to development of severe metabolic acidosis. Previous studies have shown that hemoglobin has high buffering capacity and erythrocytes can potentially be used for management of metabolic acidosis. The aim of this study was to evaluate the effect of fresh packed red blood cells (RBC) transfusion on survival and cardiovascular function in AlP-poisoned rats. METHODOLOGY/PRINCIPAL FINDINGS Rats were poisoned with AlP by gavage. Fresh packed RBC was transfused via tail vein after AlP administration. Acid-base balance, vital signs and mortality was assessed and compared in experimental groups. Infusion of fresh packed RBC (1.5 ml) one hour after AlP (4-15 mg/kg) intoxication was associated with a significant decrease in mortality rate. Packed RBC infusion improved blood pH, HCO3-, Na+ and Ca2+ levels. Plasma troponin level was also reduced and ECG changes were reversed following packed RBC infusion in AlP intoxicated rats. CONCLUSIONS Our results showed that fresh RBC transfusion could ameliorate metabolic acidosis and enhance survival in AlP-poisoned rat. We assume that an increase in pool of RBCs may modulate acid-base balance or potentially chelate AlP-related toxic intermediates via phosphine-hemoglobin interaction.
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Affiliation(s)
- Nastaran Rahimi
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Amir Hossein Abdolghaffari
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
- Medicinal Plants Research Center, Institute of Medicinal Plants, ACECR, Tehran, Iran
| | - Alireza Partoazar
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Nina Javadian
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Tara Dehpour
- The Whittington Hospital NHS Trust, London, United Kingdom
| | - Ali R. Mani
- UCL Division of Medicine, University College London, London, United Kingdom
| | - Ahmad R. Dehpour
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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26
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Gheibi S, Jeddi S, Kashfi K, Ghasemi A. Regulation of vascular tone homeostasis by NO and H 2S: Implications in hypertension. Biochem Pharmacol 2018; 149:42-59. [PMID: 29330066 PMCID: PMC5866223 DOI: 10.1016/j.bcp.2018.01.017] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 01/05/2018] [Indexed: 02/09/2023]
Abstract
Nitric oxide (NO) and hydrogen sulfide (H2S) are two gasotransmitters that are produced in the vasculature and contribute to the regulation of vascular tone. NO and H2S are synthesized in both vascular smooth muscle and endothelial cells; NO functions primarily through the sGC/cGMP pathway, and H2S mainly through activation of the ATP-dependent potassium channels; both leading to relaxation of vascular smooth muscle cells. A deficit in the NO/H2S homeostasis is involved in the pathogenesis of various cardiovascular diseases, especially hypertension. It is now becoming increasingly clear that there are important interactions between NO and H2S and that have a profound impact on vascular tone and this may provide insights into the new therapeutic interventions. The aim of this review is to provide a better understanding of individual and interactive roles of NO and H2S in vascular biology. Overall, available data indicate that both NO and H2S contribute to vascular (patho)physiology and in regulating blood pressure. In addition, boosting NO and H2S using various dietary sources or donors could be a hopeful therapeutic strategy in the management of hypertension.
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Affiliation(s)
- Sevda Gheibi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Neurophysiology Research Center and Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sajad Jeddi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Khosrow Kashfi
- Department of Molecular, Cellular and Biomedical Sciences, Sophie Davis School of Biomedical Education, City University of New York School of Medicine, NY, USA
| | - Asghar Ghasemi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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27
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Brauner CJ, Harter TS. Beyond just hemoglobin: Red blood cell potentiation of hemoglobin-oxygen unloading in fish. J Appl Physiol (1985) 2017; 123:935-941. [PMID: 28705992 PMCID: PMC5668442 DOI: 10.1152/japplphysiol.00114.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 06/26/2017] [Accepted: 07/09/2017] [Indexed: 11/22/2022] Open
Abstract
Teleosts comprise 95% of fish species, almost one-half of all vertebrate species, and represent one of the most successful adaptive radiation events among vertebrates. This is thought to be in part because of their unique oxygen (O2) transport system. In salmonids, recent in vitro and in vivo studies indicate that hemoglobin-oxygen (Hb-O2) unloading to tissues may be doubled or even tripled under some conditions without changes in perfusion. This is accomplished through the short circuiting of red blood cell (RBC) pH regulation, resulting in a large arterial-venous pH difference within the RBC and induced reduction in Hb-O2 affinity. This system has three prerequisites: 1) highly pH-sensitive hemoglobin, 2) rapid RBC pH regulation, and 3) a heterogeneous distribution of plasma-accessible CA in the cardiovascular system (presence in the tissues and absence at the gills). Although data are limited, these attributes may be general characteristics of teleosts. Although this system is not likely operational to the same degree in other vertebrates, some of these prerequisites do exist, and the generation and elimination of pH disequilibrium states at the RBC will likely enhance Hb-O2 unloading to some degree. In human disease states, there are conditions that may partly satisfy those for enhanced Hb-O2 unloading, tentatively an avenue for future work that may improve treatment efficacy.
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Affiliation(s)
- Colin J Brauner
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Till S Harter
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
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28
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Genetet S, Desrames A, Chouali Y, Ripoche P, Lopez C, Mouro-Chanteloup I. Stomatin modulates the activity of the Anion Exchanger 1 (AE1, SLC4A1). Sci Rep 2017; 7:46170. [PMID: 28387307 PMCID: PMC5383999 DOI: 10.1038/srep46170] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 03/09/2017] [Indexed: 12/17/2022] Open
Abstract
Anion Exchanger 1 (AE1) and stomatin are integral proteins of the red blood cell (RBC) membrane. Erythroid and kidney AE1 play a major role in HCO3- and Cl- exchange. Stomatins down-regulate the activity of many channels and transporters. Biochemical studies suggested an interaction of erythroid AE1 with stomatin. Moreover, we previously reported normal AE1 expression level in stomatin-deficient RBCs. Here, the ability of stomatin to modulate AE1-dependent Cl-/HCO3- exchange was evaluated using stopped-flow methods. In HEK293 cells expressing recombinant AE1 and stomatin, the permeabilities associated with AE1 activity were 30% higher in cells overexpressing stomatin, compared to cells with only endogenous stomatin expression. Ghosts from stomatin-deficient RBCs and controls were resealed in the presence of pH- or chloride-sensitive fluorescent probes and submitted to inward HCO3- and outward Cl- gradients. From alkalinization rate constants, we deduced a 47% decreased permeability to HCO3- for stomatin-deficient patients. Similarly, kinetics of Cl- efflux, followed by the probe dequenching, revealed a significant 42% decrease in patients. In situ Proximity Ligation Assays confirmed an interaction of AE1 with stomatin, in both HEK recombinant cells and RBCs. Here we show that stomatin modulates the transport activity of AE1 through a direct protein-protein interaction.
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Affiliation(s)
- Sandrine Genetet
- Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge, Laboratoire d'Excellence GR-Ex, 75739 Paris Cedex 15, France
| | - Alexandra Desrames
- Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge, Laboratoire d'Excellence GR-Ex, 75739 Paris Cedex 15, France
| | - Youcef Chouali
- Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge, Laboratoire d'Excellence GR-Ex, 75739 Paris Cedex 15, France
| | - Pierre Ripoche
- Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge, Laboratoire d'Excellence GR-Ex, 75739 Paris Cedex 15, France
| | - Claude Lopez
- Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge, Laboratoire d'Excellence GR-Ex, 75739 Paris Cedex 15, France
| | - Isabelle Mouro-Chanteloup
- Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge, Laboratoire d'Excellence GR-Ex, 75739 Paris Cedex 15, France
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29
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Global transformation of erythrocyte properties via engagement of an SH2-like sequence in band 3. Proc Natl Acad Sci U S A 2016; 113:13732-13737. [PMID: 27856737 DOI: 10.1073/pnas.1611904113] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Src homology 2 (SH2) domains are composed of weakly conserved sequences of ∼100 aa that bind phosphotyrosines in signaling proteins and thereby mediate intra- and intermolecular protein-protein interactions. In exploring the mechanism whereby tyrosine phosphorylation of the erythrocyte anion transporter, band 3, triggers membrane destabilization, vesiculation, and fragmentation, we discovered a SH2 signature motif positioned between membrane-spanning helices 4 and 5. Evidence that this exposed cytoplasmic sequence contributes to a functional SH2-like domain is provided by observations that: (i) it contains the most conserved sequence of SH2 domains, GSFLVR; (ii) it binds the tyrosine phosphorylated cytoplasmic domain of band 3 (cdb3-PO4) with Kd = 14 nM; (iii) binding of cdb3-PO4 to erythrocyte membranes is inhibited both by antibodies against the SH2 signature sequence and dephosphorylation of cdb3-PO4; (iv) label transfer experiments demonstrate the covalent transfer of photoactivatable biotin from isolated cdb3-PO4 (but not cdb3) to band 3 in erythrocyte membranes; and (v) phosphorylation-induced binding of cdb3-PO4 to the membrane-spanning domain of band 3 in intact cells causes global changes in membrane properties, including (i) displacement of a glycolytic enzyme complex from the membrane, (ii) inhibition of anion transport, and (iii) rupture of the band 3-ankyrin bridge connecting the spectrin-based cytoskeleton to the membrane. Because SH2-like motifs are not retrieved by normal homology searches for SH2 domains, but can be found in many tyrosine kinase-regulated transport proteins using modified search programs, we suggest that related cases of membrane transport proteins containing similar motifs are widespread in nature where they participate in regulation of cell properties.
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30
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Richardson SL, Swietach P. Red blood cell thickness is evolutionarily constrained by slow, hemoglobin-restricted diffusion in cytoplasm. Sci Rep 2016; 6:36018. [PMID: 27777410 PMCID: PMC5078773 DOI: 10.1038/srep36018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 10/11/2016] [Indexed: 11/09/2022] Open
Abstract
During capillary transit, red blood cells (RBCs) must exchange large quantities of CO2 and O2 in typically less than one second, but the degree to which this is rate-limited by diffusion through cytoplasm is not known. Gas diffusivity is intuitively assumed to be fast and this would imply that the intracellular path-length, defined by RBC shape, is not a factor that could meaningfully compromise physiology. Here, we evaluated CO2 diffusivity (DCO2) in RBCs and related our results to cell shape. DCO2 inside RBCs was determined by fluorescence imaging of [H+] dynamics in cells under superfusion. This method is based on the principle that H+ diffusion is facilitated by CO2/HCO3- buffer and thus provides a read-out of DCO2. By imaging the spread of H+ ions from a photochemically-activated source (6-nitroveratraldehyde), DCO2 in human RBCs was calculated to be only 5% of the rate in water. Measurements on RBCs containing different hemoglobin concentrations demonstrated a halving of DCO2 with every 75 g/L increase in mean corpuscular hemoglobin concentration (MCHC). Thus, to compensate for highly-restricted cytoplasmic diffusion, RBC thickness must be reduced as appropriate for its MCHC. This can explain the inverse relationship between MCHC and RBC thickness determined from >250 animal species.
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Affiliation(s)
- Sarah L Richardson
- Department of Physiology, Anatomy and Genetics, Oxford OX1 3PT, European Union, United Kingdom
| | - Pawel Swietach
- Department of Physiology, Anatomy and Genetics, Oxford OX1 3PT, European Union, United Kingdom
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31
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Bijukumar D, Choonara YE, Murugan K, Choonara BF, Kumar P, du Toit LC, Pillay V. Design of an Inflammation-Sensitive Polyelectrolyte-Based Topical Drug Delivery System for Arthritis. AAPS PharmSciTech 2016; 17:1075-85. [PMID: 26515798 DOI: 10.1208/s12249-015-0434-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 10/09/2015] [Indexed: 11/30/2022] Open
Abstract
The most successful treatment strategy for arthritis is intra-articular injections that are costly and have reduced patient compliance. The purpose of the current study was to develop an inflammation-sensitive system for topical drug administration. Multi-macromolecular alginate-hyaluronic acid-chitosan (A-H-C) polyelectrolyte complex nanoparticles, loaded with indomethacin were developed employing pre-gel and post-gel techniques in the presence of dodecyl-L-pyroglutamate (DLP). In addition to in vitro studies, in silico simulations were performed to affirm and associate the molecular interactions inherent to the formulation of core all-natural multi-component biopolymeric architectures composed of an anionic (alginate), a cationic (chitosan), and an amphi-ionic polyelectrolytic (hyaluronic acid) macromolecule. The results demonstrated that DLP significantly influenced the size of the synthesized nanoparticles. Drug-content analysis revealed higher encapsulation efficiency (77.3%) in the presence of DLP, irrespective of the techniques used. Moreover, in vitro drug release studies showed that indomethacin release from the nanosystem was significantly improved (98%) in Fenton's reagent. Drug permeation across a cellulose membrane using a Franz diffusion cell system showed an initial surge flux (0.125 mg/cm(-2)/h), followed by sustained release of indomethacin for the post-gel nanoparticles revealing its effective skin permeation efficiency. In conclusion, the study presents novel nanoparticles which could effectively encapsulate and deliver hydrophobic drugs to the target site, particularly for arthritis.
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32
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Alterations in Red Blood Cell Functionality Induced by an Indole Scaffold Containing a Y-Iminodiketo Moiety: Potential Antiproliferative Conditions. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:2104247. [PMID: 27651854 PMCID: PMC5019890 DOI: 10.1155/2016/2104247] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 07/06/2016] [Accepted: 07/11/2016] [Indexed: 02/04/2023]
Abstract
We have recently proposed a new erythrocyte-based model of study to predict the antiproliferative effects of selected heterocyclic scaffolds. Starting from the metabolic similarity between erythrocytes and cancer cells, we have demonstrated how the metabolic derangement induced by an indolone-based compound (DPIT) could be related to its antiproliferative effects. In order to prove the validity of our biochemical approach, in the present study the effects on erythrocyte functionality of its chemical precursor (PID), whose synthesis we reported, were investigated. The influence of the tested compound on band 3 protein (B3), oxidative state, ATP efflux, caspase 3, metabolism, intracellular pH, and Ca2+ homeostasis has been evaluated. PID crosses the membrane localizing into the cytosol, increases anion exchange, induces direct caspase activation, shifts the erythrocytes towards an oxidative state, and releases less ATP than in normal conditions. Analysis of phosphatidylserine externalization shows that PID slightly induces apoptosis. Our findings indicate that, due to its unique features, erythrocyte responses to exogenous molecular stimuli can be fruitfully correlated at structurally more complex cells, such as cancer cells. Overall, our work indicates that erythrocyte is a powerful study tool to elucidate the biochemical/biological effects of selected heterocycles opening considerable perspectives in the field of drug discovery.
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Walski T, Dyrda A, Dzik M, Chludzińska L, Tomków T, Mehl J, Detyna J, Gałecka K, Witkiewicz W, Komorowska M. Near infrared light induces post-translational modifications of human red blood cell proteins. Photochem Photobiol Sci 2016; 14:2035-45. [PMID: 26329012 DOI: 10.1039/c5pp00203f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
There is a growing body of evidence that near infrared (NIR) light exerts beneficial effects on cells. Its usefulness in the treatment of cancer, acute brain injuries, strokes and neurodegenerative disorders has been proposed. The mechanism of the NIR action is probably of photochemical nature, however it is not fully understood. Here, using a relatively simple biological model, human red blood cells (RBCs), and a polychromatic non-polarized light source, we investigate the impact of NIR radiation on the oxygen carrier, hemoglobin (Hb), and anion exchanger (AE1, Band 3). The exposure of intact RBCs to NIR light causes quaternary transitions in Hb, dehydration of proteins and decreases the amount of physiologically inactive methemoglobin, as detected by Raman spectroscopy. These effects are accompanied by a lowering of the intracellular pH (pHi) and changes in the cell membrane topography, as documented by atomic force microscopy (AFM). All those changes are in line with our previous studies where alterations of the membrane fluidity and membrane potential were attributed to NIR action on RBCs. The rate of the above listed changes depends strictly on the dose of NIR light that the cells receive, nonetheless it should not be considered as a thermal effect.
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Affiliation(s)
- Tomasz Walski
- Institute of Biomedical Engineering and Instrumentation, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland. and Regional Specialist Hospital in Wrocław, Research and Development Centre, Kamieńskiego 73a, 51-124 Wrocław, Poland
| | - Agnieszka Dyrda
- Institute of Biomedical Engineering and Instrumentation, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland. and Center for Biomedical Research, Faculty of Biological Sciences and Faculty of Medicine, Andrés Bello University, Santiago, Chile
| | - Małgorzata Dzik
- Institute of Biomedical Engineering and Instrumentation, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
| | - Ludmiła Chludzińska
- Institute of Biomedical Engineering and Instrumentation, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
| | - Tomasz Tomków
- Institute of Biomedical Engineering and Instrumentation, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
| | - Joanna Mehl
- Institute of Biomedical Engineering and Instrumentation, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
| | - Jerzy Detyna
- Institute of Materials Science and Applied Mechanics, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Katarzyna Gałecka
- Institute of Biomedical Engineering and Instrumentation, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland. and Regional Specialist Hospital in Wrocław, Research and Development Centre, Kamieńskiego 73a, 51-124 Wrocław, Poland
| | - Wojciech Witkiewicz
- Regional Specialist Hospital in Wrocław, Research and Development Centre, Kamieńskiego 73a, 51-124 Wrocław, Poland
| | - Małgorzata Komorowska
- Institute of Biomedical Engineering and Instrumentation, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland. and Regional Specialist Hospital in Wrocław, Research and Development Centre, Kamieńskiego 73a, 51-124 Wrocław, Poland
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Chernyshova ES, Zaikina YS, Tsvetovskaya GA, Strokotov DI, Yurkin MA, Serebrennikova ES, Volkov L, Maltsev VP, Chernyshev AV. Influence of magnesium sulfate on HCO3/Cl transmembrane exchange rate in human erythrocytes. J Theor Biol 2016; 393:194-202. [PMID: 26780645 DOI: 10.1016/j.jtbi.2015.12.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 12/16/2015] [Accepted: 12/18/2015] [Indexed: 10/22/2022]
Abstract
Magnesium sulfate (MgSO4) is widely used in medicine but molecular mechanisms of its protection through influence on erythrocytes are not fully understood and are considerably controversial. Using scanning flow cytometry, in this work for the first time we observed experimentally (both in situ and in vitro) a significant increase of HCO3(-)/Cl(-) transmembrane exchange rate of human erythrocytes in the presence of MgSO4 in blood. For a quantitative analysis of the obtained experimental data, we introduced and verified a molecular kinetic model, which describes activation of major anion exchanger Band 3 (or AE1) by its complexation with free intracellular Mg(2+) (taking into account Mg(2+) membrane transport and intracellular buffering). Fitting the model to our in vitro experimental data, we observed a good correspondence between theoretical and experimental kinetic curves that allowed us to evaluate the model parameters and to estimate for the first time the association constant of Mg(2+) with Band 3 as KB~0.07mM, which is in agreement with known values of the apparent Mg(2+) dissociation constant (from 0.01 to 0.1mM) that reflects experiments on enrichment of Mg(2+) at the inner erythrocyte membrane (Gunther, 2007). Results of this work partly clarify the molecular mechanisms of MgSO4 action in human erythrocytes. The method developed allows one to estimate quantitatively a perspective of MgSO4 treatment for a patient. It should be particularly helpful in prenatal medicine for early detection of pathologies associated with the risk of fetal hypoxia.
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Affiliation(s)
- Ekaterina S Chernyshova
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya 3, 630090 Novosibirsk, Russia; Novosibirsk State University, Pirogova 2, 630090 Novosibirsk, Russia
| | - Yulia S Zaikina
- Medical Centre of Siberian Branch of the Russian Academy of Science, Pirogova 25, 630090 Novosibirsk, Russia
| | - Galina A Tsvetovskaya
- ANO "Center of New Medical Technologies in Akademgorodok", Pirogova 25/4, 630090 Novosibirsk, Russia; Institute of Chemical Biology and Fundamental Medicine, Lavrentiev Avenue 8, 630090 Novosibirsk, Russia
| | - Dmitry I Strokotov
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya 3, 630090 Novosibirsk, Russia; Novosibirsk State Medical University, Krasny Prospect 52, 630091 Novosibirsk, Russia
| | - Maxim A Yurkin
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya 3, 630090 Novosibirsk, Russia; Novosibirsk State University, Pirogova 2, 630090 Novosibirsk, Russia
| | - Elena S Serebrennikova
- Medical Centre of Siberian Branch of the Russian Academy of Science, Pirogova 25, 630090 Novosibirsk, Russia
| | - Leonid Volkov
- Centre de Recherches Cliniques Etienne-Le Bel, 3001 12 Av. Nord Sherbrooke loc. # 4867, Quebec, Canada J1H 5N4
| | - Valeri P Maltsev
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya 3, 630090 Novosibirsk, Russia; Novosibirsk State University, Pirogova 2, 630090 Novosibirsk, Russia; Novosibirsk State Medical University, Krasny Prospect 52, 630091 Novosibirsk, Russia
| | - Andrei V Chernyshev
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya 3, 630090 Novosibirsk, Russia; Novosibirsk State University, Pirogova 2, 630090 Novosibirsk, Russia.
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35
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Nguyen TY, Cipriano AF, Guan RG, Zhao ZY, Liu H. In vitro interactions of blood, platelet, and fibroblast with biodegradable magnesium-zinc-strontium alloys. J Biomed Mater Res A 2015; 103:2974-86. [PMID: 25690931 DOI: 10.1002/jbm.a.35429] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 02/06/2015] [Accepted: 02/06/2015] [Indexed: 11/08/2022]
Abstract
Magnesium (Mg) alloy is an attractive class of metallic biomaterial for cardiovascular applications due to its biodegradability and mechanical properties. In this study, we investigated the degradation in blood, thrombogenicity, and cytocompatibility of Magnesium-Zinc-Strontium (Mg-Zn-Sr) alloys, specifically four Mg-4 wt % Zn-xSr (x = 0.15, 0.5, 1, and 1.5 wt %) alloys, together with pure Mg control and relevant reference materials for cardiovascular applications. Human whole blood and platelet rich plasma (PRP) were used as the incubation media to investigate the degradation behavior of the Mg-Zn-Sr alloys. The results showed that the PRP had a greater pH increase and greater concentration of Mg(2+) ions when compared with whole blood after 2 h of incubation with the same respective Mg alloys, suggesting that the Mg alloys degraded faster in PRP than in whole blood. The Mg alloy with 4 wt % Zn and 0.15 wt % Sr (named as ZSr41A) was identified as the most promising alloy for cardiovascular stent applications, because it showed slower degradation and less thrombogenicity, as indicated by the lower concentrations of Mg(2+) ions released and less deposition of platelets. Additionally, ZSr41 alloys were cytocompatible with fibroblasts in direct exposure culture in which the cells adhered and proliferated around the samples, with no statistical difference in cell adhesion density compared with the blank reference. Future studies on the ZSr41 alloys are necessary to investigate their direct interactions with other important cells in cardiovascular system, such as vascular endothelial cells and smooth muscle cells.
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Affiliation(s)
- T Y Nguyen
- Department of Bioengineering, University of California at Riverside, 900 University Avenue, Riverside, California, 92521
| | - A F Cipriano
- Department of Bioengineering, University of California at Riverside, 900 University Avenue, Riverside, California, 92521.,Materials Science and Engineering Program, University of California at Riverside, 900 University Avenue, Riverside, California, 92521
| | - Ren-Guo Guan
- School of Materials and Metallurgy, Northeastern University, Shenyang, 110004, China
| | - Zhan-Yong Zhao
- School of Materials and Metallurgy, Northeastern University, Shenyang, 110004, China
| | - Huinan Liu
- Department of Bioengineering, University of California at Riverside, 900 University Avenue, Riverside, California, 92521.,Materials Science and Engineering Program, University of California at Riverside, 900 University Avenue, Riverside, California, 92521
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Randall DJ, Rummer JL, Wilson JM, Wang S, Brauner CJ. A unique mode of tissue oxygenation and the adaptive radiation of teleost fishes. ACTA ACUST UNITED AC 2015; 217:1205-14. [PMID: 24744420 DOI: 10.1242/jeb.093526] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Teleost fishes constitute 95% of extant aquatic vertebrates, and we suggest that this is related in part to their unique mode of tissue oxygenation. We propose the following sequence of events in the evolution of their oxygen delivery system. First, loss of plasma-accessible carbonic anhydrase (CA) in the gill and venous circulations slowed the Jacobs-Stewart cycle and the transfer of acid between the plasma and the red blood cells (RBCs). This ameliorated the effects of a generalised acidosis (associated with an increased capacity for burst swimming) on haemoglobin (Hb)-O2 binding. Because RBC pH was uncoupled from plasma pH, the importance of Hb as a buffer was reduced. The decrease in buffering was mediated by a reduction in the number of histidine residues on the Hb molecule and resulted in enhanced coupling of O2 and CO2 transfer through the RBCs. In the absence of plasma CA, nearly all plasma bicarbonate ultimately dehydrated to CO2 occurred via the RBCs, and chloride/bicarbonate exchange was the rate-limiting step in CO2 excretion. This pattern of CO2 excretion across the gills resulted in disequilibrium states for CO2 hydration/dehydration reactions and thus elevated arterial and venous plasma bicarbonate levels. Plasma-accessible CA embedded in arterial endothelia was retained, which eliminated the localized bicarbonate disequilibrium forming CO2 that then moved into the RBCs. Consequently, RBC pH decreased which, in conjunction with pH-sensitive Bohr/Root Hbs, elevated arterial oxygen tensions and thus enhanced tissue oxygenation. Counter-current arrangement of capillaries (retia) at the eye and later the swim bladder evolved along with the gas gland at the swim bladder. Both arrangements enhanced and magnified CO2 and acid production and, therefore, oxygen secretion to those specialised tissues. The evolution of β-adrenergically stimulated RBC Na(+)/H(+) exchange protected gill O2 uptake during stress and further augmented plasma disequilibrium states for CO2 hydration/dehydration. Finally, RBC organophosphates (e.g. NTP) could be reduced during hypoxia to further increase Hb-O2 affinity without compromising tissue O2 delivery because high-affinity Hbs could still adequately deliver O2 to the tissues via Bohr/Root shifts. We suggest that the evolution of this unique mode of tissue O2 transfer evolved in the Triassic/Jurassic Period, when O2 levels were low, ultimately giving rise to the most extensive adaptive radiation of extant vertebrates, the teleost fishes.
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Affiliation(s)
- D J Randall
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
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Seifert R, Flick M, Bönigk W, Alvarez L, Trötschel C, Poetsch A, Müller A, Goodwin N, Pelzer P, Kashikar ND, Kremmer E, Jikeli J, Timmermann B, Kuhl H, Fridman D, Windler F, Kaupp UB, Strünker T. The CatSper channel controls chemosensation in sea urchin sperm. EMBO J 2014; 34:379-92. [PMID: 25535245 DOI: 10.15252/embj.201489376] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Sperm guidance is controlled by chemical and physical cues. In many species, Ca(2+) bursts in the flagellum govern navigation to the egg. In Arbacia punctulata, a model system of sperm chemotaxis, a cGMP signaling pathway controls these Ca(2+) bursts. The underlying Ca(2+) channel and its mechanisms of activation are unknown. Here, we identify CatSper Ca(2+) channels in the flagellum of A. punctulata sperm. We show that CatSper mediates the chemoattractant-evoked Ca(2+) influx and controls chemotactic steering; a concomitant alkalization serves as a highly cooperative mechanism that enables CatSper to transduce periodic voltage changes into Ca(2+) bursts. Our results reveal intriguing phylogenetic commonalities but also variations between marine invertebrates and mammals regarding the function and control of CatSper. The variations probably reflect functional and mechanistic adaptations that evolved during the transition from external to internal fertilization.
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Affiliation(s)
- Reinhard Seifert
- Center of Advanced European Studies and Research (Caesar), Abteilung Molekulare Neurosensorik, Bonn, Germany Marine Biological Laboratory, Woods Hole, MA, USA
| | - Melanie Flick
- Center of Advanced European Studies and Research (Caesar), Abteilung Molekulare Neurosensorik, Bonn, Germany
| | - Wolfgang Bönigk
- Center of Advanced European Studies and Research (Caesar), Abteilung Molekulare Neurosensorik, Bonn, Germany
| | - Luis Alvarez
- Center of Advanced European Studies and Research (Caesar), Abteilung Molekulare Neurosensorik, Bonn, Germany
| | | | - Ansgar Poetsch
- Ruhr-Universität Bochum Lehrstuhl Biochemie der Pflanzen, Bochum, Germany
| | - Astrid Müller
- Center of Advanced European Studies and Research (Caesar), Abteilung Molekulare Neurosensorik, Bonn, Germany
| | - Normann Goodwin
- Marine Biological Laboratory, Woods Hole, MA, USA Laboratory of Molecular Signalling, Babraham Institute, Cambridge, UK
| | - Patric Pelzer
- Marine Biological Laboratory, Woods Hole, MA, USA Institut für Anatomie und Zellbiologie, Abteilung für Funktionelle Neuroanatomie, Universität Heidelberg, Heidelberg, Germany
| | - Nachiket D Kashikar
- Marine Biological Laboratory, Woods Hole, MA, USA Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, Brighton, UK
| | - Elisabeth Kremmer
- Helmholtz-Zentrum München, Institut für Molekulare Immunologie, München, Germany
| | - Jan Jikeli
- Center of Advanced European Studies and Research (Caesar), Abteilung Molekulare Neurosensorik, Bonn, Germany
| | | | - Heiner Kuhl
- Max-Planck-Institut für Molekulare Genetik, Berlin, Germany
| | - Dmitry Fridman
- Center of Advanced European Studies and Research (Caesar), Abteilung Molekulare Neurosensorik, Bonn, Germany Marine Biological Laboratory, Woods Hole, MA, USA
| | - Florian Windler
- Center of Advanced European Studies and Research (Caesar), Abteilung Molekulare Neurosensorik, Bonn, Germany Marine Biological Laboratory, Woods Hole, MA, USA
| | - U Benjamin Kaupp
- Center of Advanced European Studies and Research (Caesar), Abteilung Molekulare Neurosensorik, Bonn, Germany Marine Biological Laboratory, Woods Hole, MA, USA
| | - Timo Strünker
- Center of Advanced European Studies and Research (Caesar), Abteilung Molekulare Neurosensorik, Bonn, Germany Marine Biological Laboratory, Woods Hole, MA, USA
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van 't Erve TJ, Doskey CM, Wagner BA, Hess JR, Darbro BW, Ryckman KK, Murray JC, Raife TJ, Buettner GR. Heritability of glutathione and related metabolites in stored red blood cells. Free Radic Biol Med 2014; 76:107-13. [PMID: 25108189 PMCID: PMC4252477 DOI: 10.1016/j.freeradbiomed.2014.07.040] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 07/15/2014] [Accepted: 07/29/2014] [Indexed: 12/27/2022]
Abstract
Red blood cells (RBCs) collected for transfusion deteriorate during storage. This deterioration is termed the "RBC storage lesion." There is increasing concern over the safety, therapeutic efficacy, and toxicity of transfusing longer-stored units of blood. The severity of the RBC storage lesion is dependent on storage time and varies markedly between individuals. Oxidative damage is considered a significant factor in the development of the RBC storage lesion. In this study, the variability during storage and heritability of antioxidants and metabolites central to RBC integrity and function were investigated. In a classic twin study, we determined the heritability of glutathione (GSH), glutathione disulfide (GSSG), the status of the GSSG,2H(+)/2GSH couple (Ehc), and total glutathione (tGSH) in donated RBCs over 56 days of storage. Intracellular GSH and GSSG concentrations both decrease during storage (median net loss of 0.52 ± 0.63 mM (median ± SD) and 0.032 ± 0.107 mM, respectively, over 42 days). Taking into account the decline in pH, Ehc became more positive (oxidized) during storage (median net increase of 35 ± 16 mV). In our study population heritability estimates for GSH, GSSG, tGSH, and Ehc measured over 56 days of storage are 79, 60, 67, and, 75%, respectively. We conclude that susceptibility of stored RBCs to oxidative injury due to variations in the GSH redox buffer is highly variable among individual donors and strongly heritable. Identifying the genes that regulate the storage-related changes in this redox buffer could lead to the development of new methods to minimize the RBC storage lesion.
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Affiliation(s)
- Thomas J van 't Erve
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA 52242, USA
| | - Claire M Doskey
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA 52242, USA
| | - Brett A Wagner
- Free Radical and Radiation Biology Program, Radiation Oncology, The University of Iowa, Iowa City, IA 52242, USA
| | - John R Hess
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA
| | - Benjamin W Darbro
- Department of Pediatrics, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Kelli K Ryckman
- Department of Epidemiology, College of Public Health, The University of Iowa, Iowa City, IA 52242, USA
| | - Jeffrey C Murray
- Department of Pathology, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Thomas J Raife
- Holden Comprehensive Cancer Center, The University of Iowa, Iowa City, IA 52242, USA
| | - Garry R Buettner
- Free Radical and Radiation Biology Program, Radiation Oncology, The University of Iowa, Iowa City, IA 52242, USA; Holden Comprehensive Cancer Center, The University of Iowa, Iowa City, IA 52242, USA.
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Swietach P, Vaughan-Jones RD, Harris AL, Hulikova A. The chemistry, physiology and pathology of pH in cancer. Philos Trans R Soc Lond B Biol Sci 2014; 369:20130099. [PMID: 24493747 DOI: 10.1098/rstb.2013.0099] [Citation(s) in RCA: 338] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cell survival is conditional on the maintenance of a favourable acid-base balance (pH). Owing to intensive respiratory CO2 and lactic acid production, cancer cells are exposed continuously to large acid-base fluxes, which would disturb pH if uncorrected. The large cellular reservoir of H(+)-binding sites can buffer pH changes but, on its own, is inadequate to regulate intracellular pH. To stabilize intracellular pH at a favourable level, cells control trans-membrane traffic of H(+)-ions (or their chemical equivalents, e.g. ) using specialized transporter proteins sensitive to pH. In poorly perfused tumours, additional diffusion-reaction mechanisms, involving carbonic anhydrase (CA) enzymes, fine-tune control extracellular pH. The ability of H(+)-ions to change the ionization state of proteins underlies the exquisite pH sensitivity of cellular behaviour, including key processes in cancer formation and metastasis (proliferation, cell cycle, transformation, migration). Elevated metabolism, weakened cell-to-capillary diffusive coupling, and adaptations involving H(+)/H(+)-equivalent transporters and extracellular-facing CAs give cancer cells the means to manipulate micro-environmental acidity, a cancer hallmark. Through genetic instability, the cellular apparatus for regulating and sensing pH is able to adapt to extracellular acidity, driving disease progression. The therapeutic potential of disturbing this sequence by targeting H(+)/H(+)-equivalent transporters, buffering or CAs is being investigated, using monoclonal antibodies and small-molecule inhibitors.
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Affiliation(s)
- Pawel Swietach
- Department of Physiology, Anatomy and Genetics, University of Oxford, , Oxford, UK
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40
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van 't Erve TJ, Wagner BA, Ryckman KK, Raife TJ, Buettner GR. The concentration of glutathione in human erythrocytes is a heritable trait. Free Radic Biol Med 2013; 65:742-749. [PMID: 23938402 PMCID: PMC3859832 DOI: 10.1016/j.freeradbiomed.2013.08.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 07/31/2013] [Accepted: 08/02/2013] [Indexed: 12/17/2022]
Abstract
Glutathione (GSH) is a ubiquitous, redox-active, small molecule that is critical to cellular and organism health. In red blood cells (RBCs), the influence of the environment (e.g., diet and lifestyle) on GSH levels has been demonstrated in numerous studies. However, it remains unknown if levels of GSH are determined principally by environmental factors or if there is a genetic component, i.e., heritability. To investigate this we conducted a twin study. Twin studies are performed by comparing the similarity in phenotypes between mono- and dizygotic twin pairs. We determined the heritability of GSH, as well as its oxidation product glutathione disulfide (GSSG), the sum of GSH equivalents (tGSH), and the status of the GSSG/2GSH couple (marker of oxidation status, Ehc) in RBCs. In our study population we found that the estimated heritability for the intracellular concentration of GSH in RBCs was 57 %; for GSSG it was 51 %, tGSH 63 %, and Ehc 70 %. We conclude that a major portion of the phenotype of these traits is controlled genetically. We anticipate that these heritabilities will also be reflected in other cell types. The discovery that genetics plays a major role in the innate levels of redox-active species in RBCs is paradigm shifting and opens new avenues of research in the field of redox biology. Inherited RBC antioxidant levels may be important disease modifiers. By identifying the relative contributions of genes and the environment to antioxidant variation between individuals, new therapeutic strategies can be developed. Understanding the genetic determinants of these inherited traits may allow personalized approaches to relevant therapies.
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Affiliation(s)
- Thomas J van 't Erve
- Interdisciplinary Program in Human Toxicology, The University of Iowa, Iowa City, IA 52242, USA
| | - Brett A Wagner
- Free Radical and Radiation Biology Program, Radiation Oncology, The University of Iowa, Iowa City, IA 52242, USA
| | - Kelli K Ryckman
- Department of Epidemiology, College of Public Health, The University of Iowa, Iowa City, IA 52242, USA
| | - Thomas J Raife
- Department of Pathology, Carver College of Medicine, and The University of Iowa, Iowa City, IA 52242, USA
| | - Garry R Buettner
- Free Radical and Radiation Biology Program, Radiation Oncology, The University of Iowa, Iowa City, IA 52242, USA; Holden Comprehensive Cancer Center, The University of Iowa, Iowa City, IA 52242, USA.
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Jennings ML. Transport of H2S and HS(-) across the human red blood cell membrane: rapid H2S diffusion and AE1-mediated Cl(-)/HS(-) exchange. Am J Physiol Cell Physiol 2013; 305:C941-50. [PMID: 23864610 PMCID: PMC4042536 DOI: 10.1152/ajpcell.00178.2013] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The rates of H2S and HS(-) transport across the human erythrocyte membrane were estimated by measuring rates of dissipation of pH gradients in media containing 250 μM H2S/HS(-). Net acid efflux is caused by H2S/HS(-) acting analogously to CO2/HCO3(-) in the Jacobs-Stewart cycle. The steps are as follows: 1) H2S efflux through the lipid bilayer and/or a gas channel, 2) extracellular H2S deprotonation, 3) HS(-) influx in exchange for Cl(-), catalyzed by the anion exchange protein AE1, and 4) intracellular HS(-) protonation. Net acid transport by the Cl(-)/HS(-)/H2S cycle is more efficient than by the Cl(-)/HCO3(-)/CO2 cycle because of the rapid H2S-HS(-) interconversion in cells and medium. The rates of acid transport were analyzed by solving the mass flow equations for the cycle to produce estimates of the HS(-) and H2S transport rates. The data indicate that HS(-) is a very good substrate for AE1; the Cl(-)/HS(-) exchange rate is about one-third as rapid as Cl(-)/HCO3(-) exchange. The H2S permeability coefficient must also be high (>10(-2) cm/s, half time <0.003 s) to account for the pH equilibration data. The results imply that H2S and HS(-) enter erythrocytes very rapidly in the microcirculation of H2S-producing tissues, thereby acting as a sink for H2S and lowering the local extracellular concentration, and the fact that HS(-) is a substrate for a Cl(-)/HCO3(-) exchanger indicates that some effects of exogenous H2S/HS(-) may not result from a regulatory role of H2S but, rather, from net acid flux by H2S and HS(-) transport in a Jacobs-Stewart cycle.
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Affiliation(s)
- Michael L Jennings
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
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Al-Samir S, Papadopoulos S, Scheibe RJ, Meißner JD, Cartron JP, Sly WS, Alper SL, Gros G, Endeward V. Activity and distribution of intracellular carbonic anhydrase II and their effects on the transport activity of anion exchanger AE1/SLC4A1. J Physiol 2013; 591:4963-82. [PMID: 23878365 DOI: 10.1113/jphysiol.2013.251181] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We have investigated the previously published 'metabolon hypothesis' postulating that a close association of the anion exchanger 1 (AE1) and cytosolic carbonic anhydrase II (CAII) exists that greatly increases the transport activity of AE1. We study whether there is a physical association of and direct functional interaction between CAII and AE1 in the native human red cell and in tsA201 cells coexpressing heterologous fluorescent fusion proteins CAII-CyPet and YPet-AE1. In these doubly transfected tsA201 cells, YPet-AE1 is clearly associated with the cell membrane, whereas CAII-CyPet is homogeneously distributed throughout the cell in a cytoplasmic pattern. Förster resonance energy transfer measurements fail to detect close proximity of YPet-AE1 and CAII-CyPet. The absence of an association of AE1 and CAII is supported by immunoprecipitation experiments using Flag-antibody against Flag-tagged AE1 expressed in tsA201 cells, which does not co-precipitate native CAII but co-precipitates coexpressed ankyrin. Both the CAII and the AE1 fusion proteins are fully functional in tsA201 cells as judged by CA activity and by cellular HCO3(-) permeability (P(HCO3(-))) sensitive to inhibition by 4,4-Diisothiocyano-2,2-stilbenedisulfonic acid. Expression of the non-catalytic CAII mutant V143Y leads to a drastic reduction of endogenous CAII and to a corresponding reduction of total intracellular CA activity. Overexpression of an N-terminally truncated CAII lacking the proposed site of interaction with the C-terminal cytoplasmic tail of AE1 substantially increases intracellular CA activity, as does overexpression of wild-type CAII. These variously co-transfected tsA201 cells exhibit a positive correlation between cellular P(HCO3(-)) and intracellular CA activity. The relationship reflects that expected from changes in cytoplasmic CA activity improving substrate supply to or removal from AE1, without requirement for a CAII-AE1 metabolon involving physical interaction. A functional contribution of the hypothesized CAII-AE1 metabolon to erythroid AE1-mediated HCO3(-) transport was further tested in normal red cells and red cells from CAII-deficient patients that retain substantial CA activity associated with the erythroid CAI protein lacking the proposed AE1-binding sequence. Erythroid P(HCO3(-)) was indistinguishable in these two cell types, providing no support for the proposed functional importance of the physical interaction of CAII and AE1. A theoretical model predicts that homogeneous cytoplasmic distribution of CAII is more favourable for cellular transport of HCO3(-) and CO2 than is association of CAII with the cytoplasmic surface of the plasma membrane. This is due to the fact that the relatively slow intracellular transport of H(+) makes it most efficient to place the CA in the vicinity of the haemoglobin molecules, which are homogeneously distributed over the cytoplasm.
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Affiliation(s)
- Samer Al-Samir
- G. Gros: Zentrum Physiologie, Vegetative Physiologie 4220, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, 30625 Hannover, Germany. ; V. Endeward: Zentrum Physiologie 4220, Medizinische Hochschule Hannover, Germany.
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Hyttel-Sorensen S, Kleiser S, Wolf M, Greisen G. Calibration of a prototype NIRS oximeter against two commercial devices on a blood-lipid phantom. BIOMEDICAL OPTICS EXPRESS 2013; 4:1662-72. [PMID: 24049687 PMCID: PMC3771837 DOI: 10.1364/boe.4.001662] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 06/27/2013] [Accepted: 06/28/2013] [Indexed: 05/02/2023]
Abstract
In a blood-lipid liquid phantom the prototype near-infrared spectroscopy oximeter OxyPrem was calibrated against the INVOS® 5100c adult sensor in respect to values of regional tissue oxygen haemoglobin saturation (rStO2) for possible inclusion in the randomised clinical trial - SafeBoosC. In addition different commercial NIRS oximeters were compared on changing haemoglobin oxygen saturation and compared against co-oximetry. The best calibration was achieved with a simple offset and a linear scaling of the OxyPrem rStO2 values. The INVOS adult and pediatric sensor gave systematically different values, while the difference between the NIRO® 300 and the two INVOS sensors were magnitude dependent. The co-oximetry proved unreliable on such low haemoglobin and high Intralipid levels.
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Affiliation(s)
- Simon Hyttel-Sorensen
- Department of Neonatology, National University Hospital, Rigshospitalet, Blegdamsvej 9, Copenhagen, DK-2100, Denmark
| | - Stefan Kleiser
- Biomedical Optics Research Laboratory, Division of Neonatology, University Hospital of Zürich 8091 Zürich, Switzerland
| | - Martin Wolf
- Biomedical Optics Research Laboratory, Division of Neonatology, University Hospital of Zürich 8091 Zürich, Switzerland
| | - Gorm Greisen
- Department of Neonatology, National University Hospital, Rigshospitalet, Blegdamsvej 9, Copenhagen, DK-2100, Denmark
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Khan AA, Surrao DC. The importance of bicarbonate and nonbicarbonate buffer systems in batch and continuous flow bioreactors for articular cartilage tissue engineering. Tissue Eng Part C Methods 2011; 18:358-68. [PMID: 22092352 DOI: 10.1089/ten.tec.2011.0137] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In cartilage tissue engineering an optimized culture system, maintaining an appropriate extracellular environment (e.g., pH of media), can increase cell proliferation and extracellular matrix (ECM) accumulation. We have previously reported on a continuous-flow bioreactor that improves tissue growth by supplying the cells with a near infinite supply of medium. Previous studies have observed that acidic environments reduce ECM synthesis and chondrocyte proliferation. Hence, in this study we investigated the combined effects of a continuous culture system (bioreactor) together with additional buffering agents (e.g., sodium bicarbonate [NaHCO₃]) on cartilaginous tissue growth in vitro. Isolated bovine chondrocytes were grown in three-dimensional cultures, either in static conditions or in a continuous-flow bioreactor, in media with or without NaHCO₃. Tissue constructs cultivated in the bioreactor with NaHCO₃-supplemented media were characterized with significantly increased (p<0.05) ECM accumulation (glycosaminoglycans a 98-fold increase; collagen a 25-fold increase) and a 13-fold increase in cell proliferation, in comparison with static cultures. Additionally, constructs grown in the bioreactor with NaHCO₃-supplemented media were significantly thicker than all other constructs (p<0.05). Further, the chondrocytes from the primary construct expanded and synthesized ECM, forming a secondary construct without a separate expansion phase, with a diameter and thickness of 4 mm and 0.72 mm respectively. Tissue outgrowth was negligible in all other culturing conditions. Thus this study demonstrates the advantage of employing a continuous flow bioreactor coupled with NaHCO₃ supplemented media for articular cartilage tissue engineering.
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Affiliation(s)
- Aasma A Khan
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, Oxfordshire, United Kingdom.
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Seear RV, Lew VL. IKCa agonist (NS309)-elicited all-or-none dehydration response of human red blood cells is cell-age dependent. Cell Calcium 2011; 50:444-8. [DOI: 10.1016/j.ceca.2011.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2011] [Revised: 07/04/2011] [Accepted: 07/11/2011] [Indexed: 11/24/2022]
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Johnson DE, Casey JR. Cytosolic H+ microdomain developed around AE1 during AE1-mediated Cl-/HCO3- exchange. J Physiol 2011; 589:1551-69. [PMID: 21300752 DOI: 10.1113/jphysiol.2010.201483] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Microdomains, regions of discontinuous cytosolic solute concentration enhanced by rapid solute transport and slow diffusion rates, have many cellular roles. pH-regulatory membrane transporters, like the Cl−/HCO3− exchanger AE1, could develop H+ microdomains since AE1 has a rapid transport rate and cytosolic H+ diffusion is slow. We examined whether the pH environment surrounding AE1 differs from other cellular locations. As AE1 drives Cl−/HCO3− exchange, differences in pH, near and remote from AE1, were monitored by confocal microscopy using two pH-sensitive fluorescent proteins: deGFP4 (GFP) and mNectarine (mNect). Plasma membrane (PM) pH (defined as ∼1 μm region around the cell periphery) was monitored by GFP fused to AE1 (GFP.AE1), and mNect fused to an inactive mutant of the Na+-coupled nucleoside co-transporter, hCNT3 (mNect.hCNT3). GFP.AE1 to mNect.hCNT3 distance was varied by co-expression of different amounts of the two proteins in HEK293 cells. As the GFP.AE1–mNect.hCNT3 distance increased, mNect.hCNT3 detected the Cl−/HCO3− exchange-associated cytosolic pH change with a time delay and reduced rate of pH change compared to GFP.AE1. We found that a H+ microdomain 0.3 μm in diameter forms around GFP.AE1 during physiological HCO3− transport. Carbonic anhydrase isoform II inhibition prevented H+ microdomain formation. We also measured the rate of H+ movement from PM GFP.AE1 to endoplasmic reticulum (ER), using mNect fused to the cytosolic face of ER-resident calnexin (CNX.mNect). The rate of H+ diffusion through cytosol was 60-fold faster than along the cytosolic surface of the plasma membrane. The pH environment surrounding pH regulatory transport proteins may differ as a result of H+ microdomain formation, which will affect nearby pH-sensitive processes.
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Affiliation(s)
- Danielle E Johnson
- Membrane Protein Research Group, Department of Physiology, School of Molecular and Systems Medicine, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
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