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Regulation of yeast Snf1 (AMPK) by a polyhistidine containing pH sensing module. iScience 2022; 25:105083. [PMID: 36147951 PMCID: PMC9486060 DOI: 10.1016/j.isci.2022.105083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 08/12/2022] [Accepted: 09/01/2022] [Indexed: 11/23/2022] Open
Abstract
Cellular regulation of pH is crucial for internal biological processes and for the import and export of ions and nutrients. In the yeast Saccharomyces cerevisiae, the major proton pump (Pma1) is regulated by glucose. Glucose is also an inhibitor of the energy sensor Snf1/AMPK, which is conserved in all eukaryotes. Here, we demonstrate that a poly-histidine (polyHIS) tract in the pre-kinase region (PKR) of Snf1 functions as a pH-sensing module (PSM) and regulates Snf1 activity. This regulation is independent from, and unaffected by, phosphorylation at T210, the major regulatory control of Snf1, but is controlled by the Pma1 plasma-membrane proton pump. By examining the PKR from additional yeast species, and by varying the number of histidines in the PKR, we determined that the polyHIS functions progressively. This regulation mechanism links the activity of a key enzyme with the metabolic status of the cell at any given moment.
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Villasana K, Quintero W, Montero Y, Pino C, Uzcategui O, Torres G, Prada M, Pozo L, Bauta W, Jimenez W. Effect of an ionic antineoplastic agent Cytoreg on blood chemistry in a Wistar rat model. Med Gas Res 2021; 12:18-23. [PMID: 34472498 PMCID: PMC8447950 DOI: 10.4103/2045-9912.324592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Cytoreg is an ionic therapeutic agent comprising a mixture of hydrochloric, sulfuric, phosphoric, hydrofluoric, oxalic, and citric acids. In diluted form, it has demonstrated efficacy against human cancers in vitro and in vivo. Although Cytoreg is well tolerated in mice, rats, rabbits, and dogs by oral and intravenous administration, its mechanism of action is not documented. The acidic nature of Cytoreg could potentially disrupt the pH and levels of ions and dissolved gases in the blood. Here, we report the effects of the intravenous administration of Cytoreg on the arterial pH, oxygen and carbon dioxide pressures, and bicarbonate, sodium, potassium, and chloride concentrations. Our results demonstrate that Cytoreg does not disturb the normal blood pH, ion levels, or carbon dioxide content, but increases oxygen levels in rats. These data are consistent with the excellent tolerability of intravenous Cytoreg observed in rabbits, and dogs. The study was approved by the Bioethics Committee of the University of the Andes, Venezuela (CEBIOULA) (approval No. 125) on November 3, 2019.
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Affiliation(s)
- Katiusca Villasana
- Biochemistry Laboratories, Department of Pathology, University of the Andes, Mérida, Venezuela
| | - William Quintero
- Department of Biology, Faculty of Science, University of the Andes, Mérida, Venezuela
| | | | - Cristian Pino
- Department of Technical and Experimental Surgery, Faculty of Medicine, University of the Andes, Mérida, Venezuela
| | - Oscar Uzcategui
- Department of Technical and Experimental Surgery, Faculty of Medicine, University of the Andes, Mérida, Venezuela
| | - Geizon Torres
- Vitalis, Clinical Laboratory, Smart Health Laboratory, Merida, Venezuela
| | - Mariangel Prada
- Vitalis, Clinical Laboratory, Smart Health Laboratory, Merida, Venezuela
| | - Lewis Pozo
- Cytorex de Venezuela SA, Maracaibo, Venezuela
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Magder S, Magder A, Samoukovic G. Intracellular pH regulation and the acid delusion. Can J Physiol Pharmacol 2020; 99:561-576. [PMID: 33356898 DOI: 10.1139/cjpp-2020-0631] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The hydrogen ion concentration ([H+]) in intracellular cytoplasmic fluid (ICF) must be maintained in a narrow range in all species for normal protein functions. Thus, mechanisms regulating ICF are of fundamental biological importance. Studies on the regulation of ICF [H+] have been hampered by use of pH notation, failure to consider the roles played by differences in the concentration of strong ions (strong ion difference, SID), the conservation of mass, the principle of electrical neutrality, and that [H+] and bicarbonate ions [HCO3-] are dependent variables. This argument is based on the late Peter Stewart's physical-chemical analysis of [H+] regulation reported in this journal nearly forty years ago (Stewart. 1983. Can. J. Physiol. Pharmacol. 61: 1444-1461. Doi:10.1139/y83-207). We start by outlining the principles of Stewart's analysis and then provide a general understanding of its significance for regulation of ICF [H+]. The system may initially appear complex, but it becomes evident that changes in SID dominate regulation of [H+]. The primary strong ions are Na+, K+, and Cl-, and a few organic strong anions. The second independent variable, partial pressure of carbon dioxide (PCO2), can easily be assessed. The third independent variable, the activity of intracellular weak acids ([Atot]), is much more complex but largely plays a modifying role. Attention to these principles will potentially provide new insights into ICF pH regulation.
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Affiliation(s)
- Sheldon Magder
- Department of Critical Care, McGill University Health Centre, 1001 Decarie Blvd, Montreal, QC H4A 3J1, Canada.,Department of Critical Care, McGill University Health Centre, 1001 Decarie Blvd, Montreal, QC H4A 3J1, Canada
| | - Alexandr Magder
- Department of Critical Care, McGill University Health Centre, 1001 Decarie Blvd, Montreal, QC H4A 3J1, Canada.,Department of Critical Care, McGill University Health Centre, 1001 Decarie Blvd, Montreal, QC H4A 3J1, Canada
| | - Gordan Samoukovic
- Department of Critical Care, McGill University Health Centre, 1001 Decarie Blvd, Montreal, QC H4A 3J1, Canada.,Department of Critical Care, McGill University Health Centre, 1001 Decarie Blvd, Montreal, QC H4A 3J1, Canada
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Lee CY, Horng JL, Liu ST, Lin LY. Exposure to copper nanoparticles impairs ion uptake, and acid and ammonia excretion by ionocytes in zebrafish embryos. CHEMOSPHERE 2020; 261:128051. [PMID: 33113650 DOI: 10.1016/j.chemosphere.2020.128051] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 08/15/2020] [Accepted: 08/17/2020] [Indexed: 06/11/2023]
Abstract
The potential toxicity of copper nanoparticles (CuNPs) to early stages of fishes is not fully understood, and little is known about their effects on ionocytes and associated functions. This study used zebrafish embryos as a model to investigate the toxic effects of CuNPs on two subtypes of ionocytes. Zebrafish embryos were exposed to 0.1, 1, and 3 mg L-1 CuNPs for 96 h. After exposure, whole-body Na+ and Ca2+ contents were significantly reduced at ≥0.1 mg L-1, while the K+ content had decreased at ≥1 mg L-1. H+ and NH4+ excretion by the skin significantly decreased at ≥1 mg L-1. The number of living ionocytes labeled with rhodamine-123 had significantly decreased with ≥0.1 mg L-1 CuNPs. The ionocyte subtypes of H+-ATPase-rich (HR) and Na+/K+-ATPase-rich (NaR) cells were labeled by immunostaining and had decreased with ≥1 mg L-1. Shrinkage of the apical opening of ionocytes was revealed by scanning electronic microscopy. Functional impairment was also reflected by changes in gene expressions, including ion transporters/channels and Ca2+-regulatory hormones. This study shows that CuNP exposure can impair two subtypes of ionocytes and their associated functions, including Na+/Ca2+ uptake and H+/NH4+ excretion in zebrafish embryos.
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Affiliation(s)
- Chih-Ying Lee
- Department of Life Science, School of Life Science, National Taiwan Normal University, Taipei, Taiwan; Division of Pediatric Hematology and Oncology, Department of Pediatrics, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Pediatrics, Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Jiun-Lin Horng
- Department of Anatomy and Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Sian-Tai Liu
- Department of Life Science, School of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Li-Yih Lin
- Department of Life Science, School of Life Science, National Taiwan Normal University, Taipei, Taiwan.
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Dahlke F, Lucassen M, Bickmeyer U, Wohlrab S, Puvanendran V, Mortensen A, Chierici M, Pörtner HO, Storch D. Fish embryo vulnerability to combined acidification and warming coincides with a low capacity for homeostatic regulation. J Exp Biol 2020; 223:jeb212589. [PMID: 32366687 DOI: 10.1242/jeb.212589] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 04/22/2020] [Indexed: 08/26/2023]
Abstract
The vulnerability of fish embryos and larvae to environmental factors is often attributed to a lack of adult-like organ systems (gills) and thus insufficient homeostatic capacity. However, experimental data supporting this hypothesis are scarce. Here, by using Atlantic cod (Gadus morhua) as a model, the relationship between embryo vulnerability (to projected ocean acidification and warming) and homeostatic capacity was explored through parallel analyses of stage-specific mortality and in vitro activity and expression of major ion pumps (ATP-synthase, Na+/K+-ATPase, H+-ATPase) and co-transporters (NBC1, NKCC1). Immunolocalization of these transporters was used to study ionocyte morphology in newly hatched larvae. Treatment-related embryo mortality until hatching (+20% due to acidification and warming) occurred primarily during an early period (gastrulation) characterized by extremely low ion transport capacity. Thereafter, embryo mortality decreased in parallel with an exponential increase in activity and expression of all investigated ion transporters. Significant changes in transporter activity and expression in response to acidification (+15% activity) and warming (-30% expression) indicate some potential for short-term acclimatization, although this is probably associated with energetic trade-offs. Interestingly, whole-larvae enzyme activity (supported by abundant epidermal ionocytes) reached levels similar to those previously measured in gill tissue of adult cod, suggesting that early-life stages without functional gills are better equipped in terms of ion homeostasis than previously thought. This study implies that the gastrulation period represents a critical transition from inherited (maternal) defenses to active homeostatic regulation, which facilitates enhanced resilience of later stages to environmental factors.
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Affiliation(s)
- Flemming Dahlke
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
- University of Bremen, NW 2 Leobener Str., 28359 Bremen, Germany
| | - Magnus Lucassen
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - Ulf Bickmeyer
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - Sylke Wohlrab
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
- Helmholtz Institute for Functional Marine Biodiversity, Ammerländer Heersstraße 231, 26129 Oldenburg, Germany
| | | | | | | | - Hans-Otto Pörtner
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
- University of Bremen, NW 2 Leobener Str., 28359 Bremen, Germany
| | - Daniela Storch
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
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Tseng YC, Yan JJ, Furukawa F, Hwang PP. Did Acidic Stress Resistance in Vertebrates Evolve as Na + /H + Exchanger-Mediated Ammonia Excretion in Fish? Bioessays 2020; 42:e1900161. [PMID: 32163625 DOI: 10.1002/bies.201900161] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 02/20/2020] [Indexed: 12/21/2022]
Abstract
How vertebrates evolved different traits for acid excretion to maintain body fluid pH homeostasis is largely unknown. The evolution of Na+ /H+ exchanger (NHE)-mediated NH4 + excretion in fishes is reported, and the coevolution with increased ammoniagenesis and accompanying gluconeogenesis is speculated to benefit vertebrates in terms of both internal homeostasis and energy metabolism response to acidic stress. The findings provide new insights into our understanding of the possible adaptation of fishes to progressing global environmental acidification. In human kidney, titratable H+ and NH4 + comprise the two main components of net acid excretion. V-type H+ -ATPase-mediated H+ excretion may have developed in stenohaline lampreys when they initially invaded freshwater from marine habitats, but this trait is lost in most fishes. Instead, increased reliance on NHE-mediated NH4 + excretion is gradually developed and intensified during fish evolution. Further investigations on more species will be needed to support the hypothesis. Also see the video abstract here https://youtu.be/vZuObtfm-34.
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Affiliation(s)
- Yung-Che Tseng
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Jia-Jiun Yan
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Fumiya Furukawa
- Kitasato University, School of Marine Biosciences, Tokyo, 2520373, Japan
| | - Pung-Pung Hwang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
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Warren DE, Hedrick MS. Introduction to the special issue: The state of acid-base physiology in a changing world. Comp Biochem Physiol A Mol Integr Physiol 2019; 241:110630. [PMID: 31812673 DOI: 10.1016/j.cbpa.2019.110630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Daniel E Warren
- Department of Biology, Saint Louis University, St. Louis, MO, USA.
| | - Michael S Hedrick
- Department of Biological Sciences, California State University East Bay, Hayward, CA, USA
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Effect of salinity and temperature on the expression of genes involved in branchial ion transport processes in European sea bass. J Therm Biol 2019; 85:102422. [DOI: 10.1016/j.jtherbio.2019.102422] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 09/05/2019] [Accepted: 09/17/2019] [Indexed: 12/24/2022]
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