1
|
Gashkina NA. Metal Toxicity: Effects on Energy Metabolism in Fish. Int J Mol Sci 2024; 25:5015. [PMID: 38732234 PMCID: PMC11084289 DOI: 10.3390/ijms25095015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 04/25/2024] [Accepted: 05/02/2024] [Indexed: 05/13/2024] Open
Abstract
Metals are dispersed in natural environments, particularly in the aquatic environment, and accumulate, causing adverse effects on aquatic life. Moreover, chronic polymetallic water pollution is a common problem, and the biological effects of exposure to complex mixtures of metals are the most difficult to interpret. In this review, metal toxicity is examined with a focus on its impact on energy metabolism. Mechanisms regulating adenosine triphosphate (ATP) production and reactive oxygen species (ROS) emission are considered in their dual roles in the development of cytotoxicity and cytoprotection, and mitochondria may become target organelles of metal toxicity when the transmembrane potential is reduced below its phosphorylation level. One of the main consequences of metal toxicity is additional energy costs, and the metabolic load can lead to the disruption of oxidative metabolism and enhanced anaerobiosis.
Collapse
Affiliation(s)
- Natalia A Gashkina
- Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, 19 Kosygin St., Moscow 119991, Russia
| |
Collapse
|
2
|
Wang QH, Wu RX, Ji JN, Zhang J, Niu SF, Tang BG, Miao BB, Liang ZB. Integrated Transcriptomics and Metabolomics Reveal Changes in Cell Homeostasis and Energy Metabolism in Trachinotus ovatus in Response to Acute Hypoxic Stress. Int J Mol Sci 2024; 25:1054. [PMID: 38256129 PMCID: PMC10815975 DOI: 10.3390/ijms25021054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/04/2024] [Accepted: 01/09/2024] [Indexed: 01/24/2024] Open
Abstract
Trachinotus ovatus is an economically important mariculture fish, and hypoxia has become a critical threat to this hypoxia-sensitive species. However, the molecular adaptation mechanism of T. ovatus liver to hypoxia remains unclear. In this study, we investigated the effects of acute hypoxic stress (1.5 ± 0.1 mg·L-1 for 6 h) and re-oxygenation (5.8 ± 0.3 mg·L-1 for 12 h) in T. ovatus liver at both the transcriptomic and metabolic levels to elucidate hypoxia adaptation mechanism. Integrated transcriptomics and metabolomics analyses identified 36 genes and seven metabolites as key molecules that were highly related to signal transduction, cell growth and death, carbohydrate metabolism, amino acid metabolism, and lipid metabolism, and all played key roles in hypoxia adaptation. Of these, the hub genes FOS and JUN were pivotal hypoxia adaptation biomarkers for regulating cell growth and death. During hypoxia, up-regulation of GADD45B and CDKN1A genes induced cell cycle arrest. Enhancing intrinsic and extrinsic pathways in combination with glutathione metabolism triggered apoptosis; meanwhile, anti-apoptosis mechanism was activated after hypoxia. Expression of genes related to glycolysis, gluconeogenesis, amino acid metabolism, fat mobilization, and fatty acid biosynthesis were up-regulated after acute hypoxic stress, promoting energy supply. After re-oxygenation for 12 h, continuous apoptosis favored cellular function and tissue repair. Shifting from anaerobic metabolism (glycolysis) during hypoxia to aerobic metabolism (fatty acid β-oxidation and TCA cycle) after re-oxygenation was an important energy metabolism adaptation mechanism. Hypoxia 6 h was a critical period for metabolism alteration and cellular homeostasis, and re-oxygenation intervention should be implemented in a timely way. This study thoroughly examined the molecular response mechanism of T. ovatus under acute hypoxic stress, which contributes to the molecular breeding of hypoxia-tolerant cultivars.
Collapse
Affiliation(s)
- Qing-Hua Wang
- College of Fisheries, Guangdong Ocean University, Zhanjiang 524088, China; (Q.-H.W.); (R.-X.W.); (J.-N.J.); (J.Z.); (B.-G.T.); (B.-B.M.); (Z.-B.L.)
| | - Ren-Xie Wu
- College of Fisheries, Guangdong Ocean University, Zhanjiang 524088, China; (Q.-H.W.); (R.-X.W.); (J.-N.J.); (J.Z.); (B.-G.T.); (B.-B.M.); (Z.-B.L.)
- Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524025, China
| | - Jiao-Na Ji
- College of Fisheries, Guangdong Ocean University, Zhanjiang 524088, China; (Q.-H.W.); (R.-X.W.); (J.-N.J.); (J.Z.); (B.-G.T.); (B.-B.M.); (Z.-B.L.)
| | - Jing Zhang
- College of Fisheries, Guangdong Ocean University, Zhanjiang 524088, China; (Q.-H.W.); (R.-X.W.); (J.-N.J.); (J.Z.); (B.-G.T.); (B.-B.M.); (Z.-B.L.)
- Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524025, China
| | - Su-Fang Niu
- College of Fisheries, Guangdong Ocean University, Zhanjiang 524088, China; (Q.-H.W.); (R.-X.W.); (J.-N.J.); (J.Z.); (B.-G.T.); (B.-B.M.); (Z.-B.L.)
- Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524025, China
| | - Bao-Gui Tang
- College of Fisheries, Guangdong Ocean University, Zhanjiang 524088, China; (Q.-H.W.); (R.-X.W.); (J.-N.J.); (J.Z.); (B.-G.T.); (B.-B.M.); (Z.-B.L.)
- Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524025, China
| | - Ben-Ben Miao
- College of Fisheries, Guangdong Ocean University, Zhanjiang 524088, China; (Q.-H.W.); (R.-X.W.); (J.-N.J.); (J.Z.); (B.-G.T.); (B.-B.M.); (Z.-B.L.)
| | - Zhen-Bang Liang
- College of Fisheries, Guangdong Ocean University, Zhanjiang 524088, China; (Q.-H.W.); (R.-X.W.); (J.-N.J.); (J.Z.); (B.-G.T.); (B.-B.M.); (Z.-B.L.)
| |
Collapse
|
3
|
Ackerly KL, Negrete B, Dichiera AM, Esbaugh AJ. Hypoxia acclimation improves mitochondrial efficiency in the aerobic swimming muscle of red drum (Sciaenops ocellatus). Comp Biochem Physiol A Mol Integr Physiol 2023; 282:111443. [PMID: 37201653 DOI: 10.1016/j.cbpa.2023.111443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 05/11/2023] [Accepted: 05/13/2023] [Indexed: 05/20/2023]
Abstract
Environmental hypoxia (low dissolved oxygen) is a significant threat facing fishes. As fishes require oxygen to efficiently produce ATP, hypoxia can significantly limit aerobic capacity. However, some fishes show respiratory flexibility that rescues aerobic performance, including plasticity in mitochondrial performance. This plasticity may result in increased mitochondrial efficiency (e.g., less proton leak), increased oxygen storage capacity (increased myoglobin), and oxidative capacity (e.g., higher citrate synthase activity) under hypoxia. We acclimated a hypoxia-tolerant fish, red drum (Sciaenops ocellatus), to 8-days of constant hypoxia to induce a hypoxic phenotype. Fish were terminally sampled for cardiac and red muscle tissue to quantify oxidative phosphorylation, proton leak, and maximum respiration in tissue from both hypoxia-acclimated and control fish. Tissue was also collected to assess the plasticity of citrate synthase enzyme activity and mRNA expression for select oxygen storage and antioxidant pathway transcripts. We found that mitochondrial respiration rates were not affected by hypoxia exposure in cardiac tissue, though citrate synthase activity and myoglobin expression were higher following hypoxia acclimation. Interestingly, measures of mitochondrial efficiency in red muscle significantly improved in hypoxia-acclimated individuals. Hypoxia-acclimated fish had significantly higher OXPHOS Control Efficiency, OXPHOS Capacity and Coupling Control Ratios (i.e., LEAK/OXPHOS). There was no significant change to citrate synthase activity or myoglobin expression in red muscle. Overall, these results suggest that red muscle mitochondria of hypoxia-acclimated fish more efficiently utilize oxygen, which may explain previous reports in red drum of improved aerobic swimming performance in the absence of improved maximum metabolic rate following hypoxia acclimation.
Collapse
Affiliation(s)
- Kerri Lynn Ackerly
- Marine Science Institute, The University of Texas at Austin, Port Aransas, TX 78373, USA.
| | - Benjamin Negrete
- Marine Science Institute, The University of Texas at Austin, Port Aransas, TX 78373, USA
| | - Angelina M Dichiera
- Department of Zoology, The University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Andrew J Esbaugh
- Marine Science Institute, The University of Texas at Austin, Port Aransas, TX 78373, USA
| |
Collapse
|
4
|
Pettinau L, Lancien F, Zhang Y, Mauduit F, Ollivier H, Farrell AP, Claireaux G, Anttila K. Warm, but not hypoxic acclimation, prolongs ventricular diastole and decreases the protein level of Na +/Ca 2+ exchanger to enhance cardiac thermal tolerance in European sea bass. Comp Biochem Physiol A Mol Integr Physiol 2022; 272:111266. [PMID: 35772648 DOI: 10.1016/j.cbpa.2022.111266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 06/24/2022] [Accepted: 06/24/2022] [Indexed: 10/17/2022]
Abstract
One of the physiological mechanisms that can limit the fish's ability to face hypoxia or elevated temperature, is maximal cardiac performance. Yet, few studies have measured how cardiac electrical activity and associated calcium cycling proteins change with acclimation to those environmental stressors. To examine this, we acclimated European sea bass for 6 weeks to three experimental conditions: a seasonal average temperature in normoxia (16 °C; 100% air sat.), an elevated temperature in normoxia (25 °C; 100% air sat.) and a seasonal average temperature in hypoxia (16 °C; 50% air sat.). Following each acclimation, the electrocardiogram was measured to assess how acclimation affected the different phases of cardiac cycle, the maximal heart rate (fHmax) and cardiac thermal performance during an acute increase of temperature. Whereas warm acclimation prolonged especially the diastolic phase of the ventricular contraction, reduced the fHmax and increased the cardiac arrhythmia temperature (TARR), hypoxic acclimation was without effect on these functional indices. We measured the level of two key proteins involved with cellular relaxation of cardiomyocytes, i.e. sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) and Na+/Ca2+ exchanger (NCX). Warm acclimation reduced protein level of both NCX and SERCA and hypoxic acclimation reduced SERCA protein levels without affecting NCX. The changes in ventricular NCX level correlated with the observed changes in diastole duration and fHmax as well as TARR. Our results shed new light on mechanisms of cardiac plasticity to environmental stressors and suggest that NCX might be involved with the observed functional changes, yet future studies should also measure its electrophysiological activity.
Collapse
Affiliation(s)
- Luca Pettinau
- Department of Biology, University of Turku, 20014 Turku, Finland.
| | - Frédéric Lancien
- Université de Bretagne Occidentale, CNRS, IRD, Ifremer, LEMAR, F-29280 Plouzané, France
| | - Yangfan Zhang
- Department of Zoology, Faculty of Land and Food System, University of British Columbia, Vancouver, British Columbia, Canada. https://twitter.com/theYangfanZHANG
| | - Florian Mauduit
- Université de Bretagne Occidentale, CNRS, IRD, Ifremer, LEMAR, F-29280 Plouzané, France
| | - Hélène Ollivier
- Université de Bretagne Occidentale, CNRS, IRD, Ifremer, LEMAR, F-29280 Plouzané, France
| | - Anthony P Farrell
- Department of Zoology, Faculty of Land and Food System, University of British Columbia, Vancouver, British Columbia, Canada
| | - Guy Claireaux
- Université de Bretagne Occidentale, CNRS, IRD, Ifremer, LEMAR, F-29280 Plouzané, France
| | - Katja Anttila
- Department of Biology, University of Turku, 20014 Turku, Finland. https://twitter.com/anttilaLab
| |
Collapse
|
5
|
Comparative Transcriptome Analysis of Organ-Specific Adaptive Responses to Hypoxia Provides Insights to Human Diseases. Genes (Basel) 2022; 13:genes13061096. [PMID: 35741857 PMCID: PMC9222487 DOI: 10.3390/genes13061096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/15/2022] [Accepted: 06/17/2022] [Indexed: 02/01/2023] Open
Abstract
The common carp is a hypoxia-tolerant fish, and the understanding of its ability to live in low-oxygen environments has been applied to human health issues such as cancer and neuron degeneration. Here, we investigated differential gene expression changes during hypoxia in five common carp organs including the brain, the gill, the head kidney, the liver, and the intestine. Based on RNA sequencing, gene expression changes under hypoxic conditions were detected in over 1800 genes in common carp. The analysis of these genes further revealed that all five organs had high expression-specific properties. According to the results of the GO and KEGG, the pathways involved in the adaptation to hypoxia provided information on responses specific to each organ in low oxygen, such as glucose metabolism and energy usage, cholesterol synthesis, cell cycle, circadian rhythm, and dopamine activation. DisGeNET analysis showed that some human diseases such as cancer, diabetes, epilepsy, metabolism diseases, and social ability disorders were related to hypoxia-regulated genes. Our results suggested that common carp undergo various gene regulations in different organs under hypoxic conditions, and integrative bioinformatics may provide some potential targets for advancing disease research.
Collapse
|
6
|
ÜNER AK, KAYMAK E, DOĞANYİĞİT Z, AKIN AT, BAŞARAN KE, ÖZDAMAR S, YAKAN B, AKYÜZ E. Chloroquine Decreased Kir6.2 Immunoreactivity in Chronic Hypoxic Heart. BEZMIALEM SCIENCE 2022. [DOI: 10.14235/bas.galenos.2021.5543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
|
7
|
Bieczynski F, Painefilú JC, Venturino A, Luquet CM. Expression and Function of ABC Proteins in Fish Intestine. Front Physiol 2021; 12:791834. [PMID: 34955897 PMCID: PMC8696203 DOI: 10.3389/fphys.2021.791834] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Accepted: 11/17/2021] [Indexed: 12/15/2022] Open
Abstract
In fish, the intestine is fundamental for digestion, nutrient absorption, and other functions like osmoregulation, acid-base balance, and excretion of some metabolic products. These functions require a large exchange surface area, which, in turn, favors the absorption of natural and anthropogenic foreign substances (xenobiotics) either dissolved in water or contained in the food. According to their chemical nature, nutrients, ions, and water may cross the intestine epithelium cells' apical and basolateral membranes by passive diffusion or through a wide array of transport proteins and also through endocytosis and exocytosis. In the same way, xenobiotics can cross this barrier by passive diffusion or taking advantage of proteins that transport physiological substrates. The entry of toxic substances is counterbalanced by an active efflux transport mediated by diverse membrane proteins, including the ATP binding cassette (ABC) proteins. Recent advances in structure, molecular properties, and functional studies have shed light on the importance of these proteins in cellular and organismal homeostasis. There is abundant literature on mammalian ABC proteins, while the studies on ABC functions in fish have mainly focused on the liver and, to a minor degree, on the kidney and other organs. Despite their critical importance in normal physiology and as a barrier to prevent xenobiotics incorporation, fish intestine's ABC transporters have received much less attention. All the ABC subfamilies are present in the fish intestine, although their functionality is still scarcely studied. For example, there are few studies of ABC-mediated transport made with polarized intestinal preparations. Thus, only a few works discriminate apical from basolateral transport activity. We briefly describe the main functions of each ABC subfamily reported for mammals and other fish organs to help understand their roles in the fish intestine. Our study considers immunohistochemical, histological, biochemical, molecular, physiological, and toxicological aspects of fish intestinal ABC proteins. We focus on the most extensively studied fish ABC proteins (subfamilies ABCB, ABCC, and ABCG), considering their apical or basolateral location and distribution along the intestine. We also discuss the implication of fish intestinal ABC proteins in the transport of physiological substrates and aquatic pollutants, such as pesticides, cyanotoxins, metals, hydrocarbons, and pharmaceutical products.
Collapse
Affiliation(s)
- Flavia Bieczynski
- Centro de Investigaciones en Toxicología Ambiental y Agrobiotecnología del Comahue – Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional del Comahue, Neuquén, Argentina
| | - Julio C. Painefilú
- Instituto Patagónico de Tecnologías Biológicas y Geoambientales, Consejo Nacional de Investigaciones Científicas y Técnicas – Universidad Nacional del Comahue, Bariloche, Argentina
| | - Andrés Venturino
- Centro de Investigaciones en Toxicología Ambiental y Agrobiotecnología del Comahue – Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional del Comahue, Neuquén, Argentina
| | - Carlos M. Luquet
- Laboratorio de Ecotoxicología Acuática, Subsede INIBIOMA-CEAN (CONICET – UNCo), Junín de los Andes, Argentina
| |
Collapse
|
8
|
Mandic M, Joyce W, Perry SF. The evolutionary and physiological significance of the Hif pathway in teleost fishes. J Exp Biol 2021; 224:272213. [PMID: 34533194 DOI: 10.1242/jeb.231936] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The hypoxia-inducible factor (HIF) pathway is a key regulator of cellular O2 homeostasis and an important orchestrator of the physiological responses to hypoxia (low O2) in vertebrates. Fish can be exposed to significant and frequent changes in environmental O2, and increases in Hif-α (the hypoxia-sensitive subunit of the transcription factor Hif) have been documented in a number of species as a result of a decrease in O2. Here, we discuss the impact of the Hif pathway on the hypoxic response and the contribution to hypoxia tolerance, particularly in fishes of the cyprinid lineage, which includes the zebrafish (Danio rerio). The cyprinids are of specific interest because, unlike in most other fishes, duplicated paralogs of the Hif-α isoforms arising from a teleost-specific genome duplication event have been retained. Positive selection has acted on the duplicated paralogs of the Hif-α isoforms in some cyprinid sub-families, pointing to adaptive evolutionary change in the paralogs. Thus, cyprinids are valuable models for exploring the evolutionary significance and physiological impact of the Hif pathway on the hypoxic response. Knockout in zebrafish of either paralog of Hif-1α greatly reduces hypoxia tolerance, indicating the importance of both paralogs to the hypoxic response. Here, with an emphasis on the cardiorespiratory system, we focus on the role of Hif-1α in the hypoxic ventilatory response and the regulation of cardiac function. We explore the effects of the duration of the hypoxic exposure (acute, sustained or intermittent) on the impact of Hif-1α on cardiorespiratory function and compare relevant data with those from mammalian systems.
Collapse
Affiliation(s)
- Milica Mandic
- Department of Animal Science, 2251 Meyer Hall, University of California Davis, Davis, CA 95616, USA
| | - William Joyce
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, Canada, K1N 6N5.,Department of Biology - Zoophysiology, Aarhus University, C.F. Møllers Allé 3, 8000 Aarhus C, Denmark
| | - Steve F Perry
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, Canada, K1N 6N5
| |
Collapse
|
9
|
Filice M, Imbrogno S, Gattuso A, Cerra MC. Hypoxic and Thermal Stress: Many Ways Leading to the NOS/NO System in the Fish Heart. Antioxidants (Basel) 2021; 10:1401. [PMID: 34573033 PMCID: PMC8471457 DOI: 10.3390/antiox10091401] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 08/27/2021] [Accepted: 08/30/2021] [Indexed: 12/22/2022] Open
Abstract
Teleost fish are often regarded with interest for the remarkable ability of several species to tolerate even dramatic stresses, either internal or external, as in the case of fluctuations in O2 availability and temperature regimes. These events are naturally experienced by many fish species under different time scales, but they are now exacerbated by growing environmental changes. This further challenges the intrinsic ability of animals to cope with stress. The heart is crucial for the stress response, since a proper modulation of the cardiac function allows blood perfusion to the whole organism, particularly to respiratory organs and the brain. In cardiac cells, key signalling pathways are activated for maintaining molecular equilibrium, thus improving stress tolerance. In fish, the nitric oxide synthase (NOS)/nitric oxide (NO) system is fundamental for modulating the basal cardiac performance and is involved in the control of many adaptive responses to stress, including those related to variations in O2 and thermal regimes. In this review, we aim to illustrate, by integrating the classic and novel literature, the current knowledge on the NOS/NO system as a crucial component of the cardiac molecular mechanisms that sustain stress tolerance and adaptation, thus providing some species, such as tolerant cyprinids, with a high resistance to stress.
Collapse
Affiliation(s)
| | - Sandra Imbrogno
- Department of Biology, Ecology and Earth Sciences, University of Calabria, 87036 Arcavacata di Rende, Italy; (M.F.); (M.C.C.)
| | - Alfonsina Gattuso
- Department of Biology, Ecology and Earth Sciences, University of Calabria, 87036 Arcavacata di Rende, Italy; (M.F.); (M.C.C.)
| | | |
Collapse
|
10
|
Liu X, Li Z, Yan Y, Li Y, Wu H, Pei J, Yan P, Yang R, Guo X, Lan X. Selection and introgression facilitated the adaptation of Chinese native endangered cattle in extreme environments. Evol Appl 2021; 14:860-873. [PMID: 33767758 PMCID: PMC7980270 DOI: 10.1111/eva.13168] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 08/31/2020] [Accepted: 11/03/2020] [Indexed: 12/18/2022] Open
Abstract
Although persistent efforts have identified and characterized a few candidate genes and related biological processes with potential functions in the adaptation of many species to extreme environments, few works have been conducted to determine the genomic basis of adaptation in endangered livestock breeds that have been living in extreme conditions for more than thousands of years. To fill this gap, we sequenced the whole genomes of nine individuals from three Chinese native endangered cattle breeds that are living in high-altitude or arid environments. Phylogenetic and evolutionary history analyses of these three and other six breeds showed that the genetic structure of the cattle populations is primarily related to geographic location. Interestingly, we identified pervasive introgression from the yak to Zhangmu cattle (ZMC) that cover several genes (e.g., NOS2, EGLN1 and EPAS1) involved in the hypoxia response and previously identified as positive selection genes in other species, which suggested that the adaptive introgression from yak may have contributed to the adaptation of ZMC to high-altitude environments. In addition, by contrasting the breeds in opposite living conditions, we revealed a set of candidate genes with various functions from hypoxia response, water metabolism, immune response and body shape change to embryo development and skeletal system development, etc., that may be related to high-altitude or arid adaptation. Our research provides new insights into the recovery and adaptation of endangered native cattle and other species in extreme environments and valuable resources for future research on animal husbandry to cope with climate change.
Collapse
Affiliation(s)
- Xinfeng Liu
- College of Animal Science and TechnologyNorthwest A&F UniversityYanglingChina
- College of Life SciencesNorthwest A&F UniversityYanglingChina
| | - Zhaohong Li
- College of Life SciencesNorthwest A&F UniversityYanglingChina
| | - Yubin Yan
- College of Life SciencesNorthwest A&F UniversityYanglingChina
| | - Ye Li
- College of Life SciencesNorthwest A&F UniversityYanglingChina
| | - Hui Wu
- College of Animal Science and TechnologyNorthwest A&F UniversityYanglingChina
- College of Life SciencesNorthwest A&F UniversityYanglingChina
| | - Jie Pei
- Lanzhou Institute of Husbandry and Pharmaceutical SciencesChinese Academy of Agricultural SciencesLanzhouChina
| | - Ping Yan
- Lanzhou Institute of Husbandry and Pharmaceutical SciencesChinese Academy of Agricultural SciencesLanzhouChina
| | - Ruolin Yang
- College of Life SciencesNorthwest A&F UniversityYanglingChina
| | - Xian Guo
- Lanzhou Institute of Husbandry and Pharmaceutical SciencesChinese Academy of Agricultural SciencesLanzhouChina
| | - Xianyong Lan
- College of Animal Science and TechnologyNorthwest A&F UniversityYanglingChina
| |
Collapse
|
11
|
Stecyk JAW, Couturier CS, Abramochkin DV, Hall D, Arrant-Howell A, Kubly KL, Lockmann S, Logue K, Trueblood L, Swalling C, Pinard J, Vogt A. Cardiophysiological responses of the air-breathing Alaska blackfish to cold acclimation and chronic hypoxic submergence at 5°C. J Exp Biol 2020; 223:jeb225730. [PMID: 33020178 PMCID: PMC7687868 DOI: 10.1242/jeb.225730] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 09/28/2020] [Indexed: 01/29/2023]
Abstract
The Alaska blackfish (Dallia pectoralis) remains active at cold temperatures when experiencing aquatic hypoxia without air access. To discern the cardiophysiological adjustments that permit this behaviour, we quantified the effect of acclimation from 15°C to 5°C in normoxia (15N and 5N fish), as well as chronic hypoxic submergence (6-8 weeks; ∼6.3-8.4 kPa; no air access) at 5°C (5H fish), on in vivo and spontaneous heart rate (fH), electrocardiogram, ventricular action potential (AP) shape and duration (APD), the background inward rectifier (IK1) and rapid delayed rectifier (IKr) K+ currents and ventricular gene expression of proteins involved in excitation-contraction coupling. In vivo fH was ∼50% slower in 5N than in 15N fish, but 5H fish did not display hypoxic bradycardia. Atypically, cold acclimation in normoxia did not induce shortening of APD or alter resting membrane potential. Rather, QT interval and APD were ∼2.6-fold longer in 5N than in 15N fish because outward IK1 and IKr were not upregulated in 5N fish. By contrast, chronic hypoxic submergence elicited a shortening of QT interval and APD, driven by an upregulation of IKr The altered electrophysiology of 5H fish was accompanied by increased gene expression of kcnh6 (3.5-fold; Kv11.2 of IKr), kcnj12 (7.4-fold; Kir2.2 of IK1) and kcnj14 (2.9-fold; Kir2.4 of IK1). 5H fish also exhibited a unique gene expression pattern that suggests modification of ventricular Ca2+ cycling. Overall, the findings reveal that Alaska blackfish exposed to chronic hypoxic submergence prioritize the continuation of cardiac performance to support an active lifestyle over reducing cardiac ATP demand.
Collapse
Affiliation(s)
- Jonathan A W Stecyk
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA
| | - Christine S Couturier
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA
| | - Denis V Abramochkin
- Department of Human and Animal Physiology, Lomonosov Moscow State University, 1-12 Leninskiye Gory, 119991 Moscow, Russia
- Ural Federal University, 19 Mira Street, 620002 Ekaterinburg, Russia
- Laboratory of Cardiac Physiology, Institute of Physiology of Kоmi Science Centre of the Ural Branch of the Russian Academy of Sciences, FRC Komi SC UB RAS, 50 Pervomayskaya Str., 167982 Syktyvkar, Komi Republic, Russia
| | - Diarmid Hall
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA
| | - Asia Arrant-Howell
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA
| | - Kerry L Kubly
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA
| | - Shyanne Lockmann
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA
| | - Kyle Logue
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA
| | - Lenett Trueblood
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA
| | - Connor Swalling
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA
| | - Jessica Pinard
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA
| | - Angela Vogt
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA
| |
Collapse
|
12
|
Leo S, Gattuso A, Mazza R, Filice M, Cerra MC, Imbrogno S. Cardiac influence of the β3-adrenoceptor in the goldfish ( Carassius auratus): a protective role under hypoxia? ACTA ACUST UNITED AC 2019; 222:jeb.211334. [PMID: 31527180 DOI: 10.1242/jeb.211334] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 09/11/2019] [Indexed: 12/18/2022]
Abstract
The goldfish (Carassius auratus) exhibits a remarkable capacity to survive and remain active under prolonged and severe hypoxia, making it a good model for studying cardiac function when oxygen availability is a limiting factor. Under hypoxia, the goldfish heart increases its performance, representing a putative component of hypoxia tolerance; however, the underlying mechanisms have not yet been elucidated. Here, we aimed to investigate the role of β3-adrenoreceptors (ARs) in the mechanisms that modulate goldfish heart performance along with the impact of oxygen levels. By western blotting analysis, we found that the goldfish heart expresses β3-ARs, and this expression increases under hypoxia. The effects of β3-AR stimulation were analysed by using an ex vivo working heart preparation. Under normoxia, the β3-AR-selective agonist BRL37344 (10-12 to 10-7 mol l-1) elicited a concentration-dependent increase of contractility that was abolished by a specific β3-AR antagonist (SR59230A; 10-8 mol l-1), but not by α/β1/β2-AR inhibitors (phentolamine, nadolol and ICI118,551; 10-7 mol l-1). Under acute hypoxia, BRL37344 did not affect goldfish heart performance. However, SR59230A, but not phentolamine, nadolol or ICI118,551, abolished the time-dependent enhancement of contractility that characterizes the hypoxic goldfish heart. Under both normoxia and hypoxia, adenylate cyclase and cAMP were found to be involved in the β3-AR-dependent downstream transduction pathway. In summary, we show the presence of functional β3-ARs in the goldfish heart, whose activation modulates basal performance and contributes to a hypoxia-dependent increase of contractility.
Collapse
Affiliation(s)
- Serena Leo
- Dept of Biology, Ecology and Earth Sciences (BEST), University of Calabria, Arcavacata di Rende (CS), Italy
| | - Alfonsina Gattuso
- Dept of Biology, Ecology and Earth Sciences (BEST), University of Calabria, Arcavacata di Rende (CS), Italy
| | - Rosa Mazza
- Dept of Biology, Ecology and Earth Sciences (BEST), University of Calabria, Arcavacata di Rende (CS), Italy
| | - Mariacristina Filice
- Dept of Biology, Ecology and Earth Sciences (BEST), University of Calabria, Arcavacata di Rende (CS), Italy
| | - Maria Carmela Cerra
- Dept of Biology, Ecology and Earth Sciences (BEST), University of Calabria, Arcavacata di Rende (CS), Italy
| | - Sandra Imbrogno
- Dept of Biology, Ecology and Earth Sciences (BEST), University of Calabria, Arcavacata di Rende (CS), Italy
| |
Collapse
|
13
|
Vornanen M. Electrical Excitability of the Fish Heart and Its Autonomic Regulation. FISH PHYSIOLOGY 2017. [DOI: 10.1016/bs.fp.2017.04.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
|
14
|
Tikkanen E, Haverinen J, Egginton S, Hassinen M, Vornanen M. Effects of prolonged anoxia on electrical activity of the heart in Crucian carp (Carassius carassius). J Exp Biol 2016; 220:445-454. [DOI: 10.1242/jeb.145177] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 11/15/2016] [Indexed: 01/08/2023]
Abstract
The effects of sustained anoxia on cardiac electrical excitability were examined in the anoxia-tolerant Crucian carp (Carassius carassius). The electrocardiogram (ECG) and expression of excitation-contraction coupling genes were studied in fish acclimatised to normoxia in summer (+18°C) or winter (+2°C), and in winter fish after 1, 3 and 6 weeks of anoxia. Anoxia induced a sustained bradycardia from a heart rate of 10.3±0.77 to 4.1±0.29 bpm (P<0.05) after 5 weeks, and heart rate slowly recovered to control levels when oxygen was restored. Heart rate variability greatly increased under anoxia, and completely recovered under re-oxygenation. The RT interval increased from 2.8±0.34 s in normoxia to 5.8±0.44 s under anoxia (P<0.05), which reflects a doubling of the ventricular action potential (AP) duration. Acclimatisation to winter induced extensive changes in gene expression relative to summer-acclimatised fish, including depression in those coding for the sarcoplasmic reticulum calcium pump (Serca2-q2) and ATP-sensitive K+ channels (Kir6.2) (P<0.05). Genes of delayed rectifier K+ (kcnh6) and Ca2+ channels (cacna1c) were up-regulated in winter fish (P<0.05). In contrast, the additional challenge of anoxia caused only minor changes in gene expression, e.g. depressed expression of Kir2.2b K+ channel gene (kcnj12b), whereas expression of Ca2+ (cacna1a, -c and –g) and Na+ channel genes (scn4a and scn5a) were not affected. These data suggest that low temperature pre-conditions the Crucian carp heart for winter anoxia, whereas sustained anoxic bradycardia and prolongation of AP duration are directly induced by oxygen shortage without major changes in gene expression.
Collapse
Affiliation(s)
- Elisa Tikkanen
- University of Eastern Finland, Department of Environmental and Biological Sciences, Finland
| | - Jaakko Haverinen
- University of Eastern Finland, Department of Environmental and Biological Sciences, Finland
| | | | - Minna Hassinen
- University of Eastern Finland, Department of Environmental and Biological Sciences, Finland
| | - Matti Vornanen
- University of Eastern Finland, Department of Environmental and Biological Sciences, Finland
| |
Collapse
|
15
|
Nelson PT, Jicha GA, Wang WX, Ighodaro E, Artiushin S, Nichols CG, Fardo DW. ABCC9/SUR2 in the brain: Implications for hippocampal sclerosis of aging and a potential therapeutic target. Ageing Res Rev 2015; 24:111-25. [PMID: 26226329 PMCID: PMC4661124 DOI: 10.1016/j.arr.2015.07.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 07/24/2015] [Indexed: 01/06/2023]
Abstract
The ABCC9 gene and its polypeptide product, SUR2, are increasingly implicated in human neurologic disease, including prevalent diseases of the aged brain. SUR2 proteins are a component of the ATP-sensitive potassium ("KATP") channel, a metabolic sensor for stress and/or hypoxia that has been shown to change in aging. The KATP channel also helps regulate the neurovascular unit. Most brain cell types express SUR2, including neurons, astrocytes, oligodendrocytes, microglia, vascular smooth muscle, pericytes, and endothelial cells. Thus it is not surprising that ABCC9 gene variants are associated with risk for human brain diseases. For example, Cantu syndrome is a result of ABCC9 mutations; we discuss neurologic manifestations of this genetic syndrome. More common brain disorders linked to ABCC9 gene variants include hippocampal sclerosis of aging (HS-Aging), sleep disorders, and depression. HS-Aging is a prevalent neurological disease with pathologic features of both neurodegenerative (aberrant TDP-43) and cerebrovascular (arteriolosclerosis) disease. As to potential therapeutic intervention, the human pharmacopeia features both SUR2 agonists and antagonists, so ABCC9/SUR2 may provide a "druggable target", relevant perhaps to both HS-Aging and Alzheimer's disease. We conclude that more work is required to better understand the roles of ABCC9/SUR2 in the human brain during health and disease conditions.
Collapse
Affiliation(s)
- Peter T Nelson
- University of Kentucky, Sanders-Brown Center on Aging, Lexington, KY 40536, USA; University of Kentucky, Department of Pathology, Lexington, KY 40536, USA.
| | - Gregory A Jicha
- University of Kentucky, Sanders-Brown Center on Aging, Lexington, KY 40536, USA; University of Kentucky, Department of Neurology, Lexington, KY, 40536, USA
| | - Wang-Xia Wang
- University of Kentucky, Sanders-Brown Center on Aging, Lexington, KY 40536, USA
| | - Eseosa Ighodaro
- University of Kentucky, Sanders-Brown Center on Aging, Lexington, KY 40536, USA
| | - Sergey Artiushin
- University of Kentucky, Sanders-Brown Center on Aging, Lexington, KY 40536, USA
| | - Colin G Nichols
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - David W Fardo
- University of Kentucky, Sanders-Brown Center on Aging, Lexington, KY 40536, USA; Department of Biostatistics, Lexington, KY, 40536, USA
| |
Collapse
|
16
|
Long Y, Yan J, Song G, Li X, Li X, Li Q, Cui Z. Transcriptional events co-regulated by hypoxia and cold stresses in Zebrafish larvae. BMC Genomics 2015; 16:385. [PMID: 25975375 PMCID: PMC4432979 DOI: 10.1186/s12864-015-1560-y] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 04/20/2015] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Hypoxia and temperature stress are two major adverse environmental conditions often encountered by fishes. The interaction between hypoxia and temperature stresses has been well documented and oxygen is considered to be the limiting factor for the thermal tolerance of fish. Although both high and low temperature stresses can impair the cardiovascular function and the cross-resistance between hypoxia and heat stress has been found, it is not clear whether hypoxia acclimation can protect fish from cold injury. RESULTS Pre-acclimation of 96-hpf zebrafish larvae to mild hypoxia (5% O2) significantly improved their resistance to lethal hypoxia (2.5% O2) and increased the survival rate of zebrafish larvae after lethal cold (10°C) exposure. However, pre-acclimation of 96-hpf larvae to cold (18°C) decreased their tolerance to lethal hypoxia although their ability to endure lethal cold increased. RNA-seq analysis identified 132 up-regulated and 41 down-regulated genes upon mild hypoxia exposure. Gene ontology enrichment analyses revealed that genes up-regulated by hypoxia are primarily involved in oxygen transport, oxidation-reduction process, hemoglobin biosynthetic process, erythrocyte development and cellular iron ion homeostasis. Hypoxia-inhibited genes are enriched in inorganic anion transport, sodium ion transport, very long-chain fatty acid biosynthetic process and cytidine deamination. A comparison with the dataset of cold-regulated gene expression identified 23 genes co-induced by hypoxia and cold and these genes are mainly associated with oxidation-reduction process, oxygen transport, hemopoiesis, hemoglobin biosynthetic process and cellular iron ion homeostasis. The alleviation of lipid peroxidation damage by both cold- and hypoxia-acclimation upon lethal cold stress suggests the association of these genes with cold resistance. Furthermore, the alternative promoter of hmbsb gene specifically activated by hypoxia and cold was identified and confirmed. CONCLUSIONS Acclimation responses to mild hypoxia and cold stress were found in zebrafish larvae and pre-acclimation to hypoxia significantly improved the tolerance of larvae to lethal cold stress. RNA-seq and bioinformatics analyses revealed the biological processes associated with hypoxia acclimation. Transcriptional events co-induced by hypoxia and cold may represent the molecular basis underlying the protection of hypoxia-acclimation against cold injury.
Collapse
Affiliation(s)
- Yong Long
- The Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, PR China.
| | - Junjun Yan
- The Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, PR China.
- University of the Chinese Academy of Sciences, Beijing, PR China.
| | - Guili Song
- The Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, PR China.
| | - Xiaohui Li
- The Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, PR China.
- University of the Chinese Academy of Sciences, Beijing, PR China.
| | - Xixi Li
- The Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, PR China.
- University of the Chinese Academy of Sciences, Beijing, PR China.
| | - Qing Li
- The Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, PR China.
| | - Zongbin Cui
- The Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, PR China.
| |
Collapse
|
17
|
The hypoxia signaling pathway and hypoxic adaptation in fishes. SCIENCE CHINA-LIFE SCIENCES 2015; 58:148-55. [DOI: 10.1007/s11427-015-4801-z] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 11/06/2014] [Indexed: 12/17/2022]
|
18
|
Haworth TE, Haverinen J, Shiels HA, Vornanen M. Electrical excitability of the heart in a Chondrostei fish, the Siberian sturgeon (Acipenser baerii). Am J Physiol Regul Integr Comp Physiol 2014; 307:R1157-66. [PMID: 25163915 DOI: 10.1152/ajpregu.00253.2014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sturgeon (family Acipenseridae) are regarded as living fossils due to their ancient origin and exceptionally slow evolution. To extend our knowledge of fish cardiac excitability to a Chondrostei fish, we examined electrophysiological phenotype of the Siberian sturgeon ( Acipenser baerii) heart with recordings of epicardial ECG, intracellular action potentials (APs), and sarcolemmal ion currents. Epicardial ECG of A. baerii had the typical waveform of the vertebrate ECG with Q-T interval (average duration of ventricular AP) of 650 ± 30 ms and an intrinsic heart rate of 45.5 ± 5 beats min−1 at 20°C. Similar to other fish species, atrial AP was shorter in duration (402 ± 33 ms) than ventricular AP (585 ± 40) ( P < 0.05) at 20°C. Densities of atrial and ventricular Na+ currents were similar (−47.6 ± 4.5 and −53.2 ± 5.1 pA/pF, respectively) and close to the typical values of teleost hearts. Two major K+ currents, the inward rectifier K+ current ( IK1), and the delayed rectifier K+ current ( IKr) were found under basal conditions in sturgeon cardiomyocytes. The atrial IKr (3.3 ± 0.2 pA/pF) was about twice as large as the ventricular IKr (1.3 ± 0.4 pA/pF) ( P < 0.05) conforming to the typical pattern of teleost cardiac IKr. Divergent from other fishes, the ventricular IK1 was remarkably small (−2.5 ± 0.07 pA/pF) and not different from that of the atrial myocytes (−1.9 ± 0.06 pA/pF) ( P > 0.05). Two ligand-gated K+ currents were also found: ACh-activated inward rectifier ( IKACh) was present only in atrial cells, while ATP-sensitive K+ current ( IKATP) was activated by a mitochondrial blocker, CCCP, in both atrial and ventricular cells. The most striking difference to other fishes appeared in Ca2+ currents ( ICa). In atrial myocytes, ICa was predominated by nickel-sensitive and nifedipine-resistant T-type ICa, while ventricular myocytes had mainly nifedipine-sensitive and nickel-resistant L-type ICa. ICaT/ ICaL ratio of the sturgeon atrial myocytes (2.42) is the highest value ever measured for a vertebrate species. In ventricular myocytes, ICaT/ ICaL ratio was 0.09. With the exception of the large atrial ICaT and small ventricular IK1, electrical excitability of A. baerii heart is similar to that of teleost hearts.
Collapse
Affiliation(s)
- Thomas Eliot Haworth
- University of Manchester, Faculty of Life Sciences, Manchester, United Kingdom; and
| | - Jaakko Haverinen
- University of Eastern Finland, Department of Biology, Joensuu, Finland
| | - Holly A. Shiels
- University of Manchester, Faculty of Life Sciences, Manchester, United Kingdom; and
| | - Matti Vornanen
- University of Eastern Finland, Department of Biology, Joensuu, Finland
| |
Collapse
|
19
|
Inhibition of the cardiac ATP-dependent potassium current by KB-R7943. Comp Biochem Physiol A Mol Integr Physiol 2014; 175:38-45. [PMID: 24845199 DOI: 10.1016/j.cbpa.2014.05.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 05/12/2014] [Accepted: 05/13/2014] [Indexed: 11/23/2022]
Abstract
KB-R7943 (2-[2-[4-(4-nitrobenzyloxy)phenyl]ethyl]isothiourea) was developed as a specific inhibitor of the sarcolemmal sodium-calcium exchanger (NCX) with potential experimental and therapeutic use. However, in cardiomyocytes KB-R7943 also effectively blocks several K(+) currents including the delayed rectifier, IKr, and background inward rectifier, IK1. In the present study we analyze the effects of KB-R7943 on the ATP-dependent potassium current (IKATP) recorded by whole-cell patch-clamp in ventricular cardiomyocytes from a mammal (mouse) and a fish (crucian carp). IKATP was induced by external application of a mitochondrial uncoupler CCCP (3×10(-7) M) and internal perfusion of the cell with ATP-free pipette solution. A weakly inwardly rectifying current with a large outward component, recorded in the presence of CCCP, was blocked with 10(-5) M glibenclamide by 56.1±4.6% and 56.9±3.6% in crucian carp and mouse ventricular myocytes, respectively. In fish cardiomyocytes IKATP was blocked by KB-R7943 with an IC50 value of 3.14×10(-7) M, while in mammalian cells IC50 was 2.8×10(-6) M (P<0.05). 10(-5) M KB-R7943 inhibited CCCP-induced IKATP by 99.9±0.13% and 97.5±1.2% in crucian carp and mouse ventricular myocytes, respectively. In crucian carp the IKATP is about an order of magnitude more sensitive to KB-R7943 than the background IK1, but in mammals IKATP and IK1 are almost equally sensitive to KB-R7943. Therefore, the ability of KB-R7943 to block IKATP should be taken into account together with INCX inhibition when investigating possible cardioprotective effects of this compound.
Collapse
|