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Jankovic A, Kalezic A, Korac A, Buzadzic B, Storey KB, Korac B. Integrated Redox-Metabolic Orchestration Sustains Life in Hibernating Ground Squirrels. Antioxid Redox Signal 2024; 40:345-368. [PMID: 36802926 DOI: 10.1089/ars.2021.0277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Significance: The ultimate manifestations of life, birth, survival under various environmental pressures and death are based on bioenergetics. Hibernation is a unique survival strategy for many small mammals that is characterised by severe metabolic depression and transition from euthermia to hypothermia (torpor) at body temperatures close to 0°C. These manifestations of life were made possible by the remarkable "social" behavior of biomolecules during billions of years of evolution: the evolution of life with oxygen. Oxygen was necessary for energy production and the evolutionary explosion of aerobic organisms. Recent Advances: Nevertheless, reactive oxygen species, formed through oxidative metabolism, are dangerous-they can kill a cell and, on the other hand, play a plethora of fundamentally valuable roles. Therefore, the evolution of life depended on energy metabolism and redox-metabolic adaptations. The more extreme the conditions for survival are, the more sophisticated the adaptive responses of organisms become. Hibernation is a beautiful illustration of this principle. Hibernating animals use evolutionarily conserved molecular mechanisms to survive adverse environmental conditions, including reducing body temperature to ambient levels (often to ∼0°C) and severe metabolic depression. This long-built secret of life lies at the intersection of oxygen, metabolism, and bioenergetics, and hibernating organisms have learned to exploit all the underlying capacities of molecular pathways to survive. Critical Issues: Despite such drastic changes in phenotype, tissues and organs of hibernators sustain no metabolic or histological damage during hibernation or upon awakening from hibernation. This was made possible by the fascinating integration of redox-metabolic regulatory networks whose molecular mechanisms remain undisclosed to this day. Future Directions: Discovering these molecular mechanisms is not warranted only to understand hibernation in itself but to help explain complex medical conditions (hypoxia/reoxygenation, organ transplantation, diabetes, and cancer) and to even help overcome limitations associated with space travel. This is a review of integrated redox-metabolic orchestration in hibernation. Antioxid. Redox Signal. 40, 345-368.
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Affiliation(s)
- Aleksandra Jankovic
- Department of Physiology, Institute for Biological Research "Sinisa Stankovic," National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Andjelika Kalezic
- Department of Physiology, Institute for Biological Research "Sinisa Stankovic," National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | | | - Biljana Buzadzic
- Department of Physiology, Institute for Biological Research "Sinisa Stankovic," National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | | | - Bato Korac
- Department of Physiology, Institute for Biological Research "Sinisa Stankovic," National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
- Faculty of Biology, University of Belgrade, Belgrade, Serbia
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2
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Staples JF, Mathers KE, Duffy BM. Mitochondrial Metabolism in Hibernation: Regulation and Implications. Physiology (Bethesda) 2022; 37:0. [PMID: 35658625 DOI: 10.1152/physiol.00006.2022] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Hibernators rapidly and reversibly suppress mitochondrial respiration and whole animal metabolism. Posttranslational modifications likely regulate these mitochondrial changes, which may help conserve energy in winter. These modifications are affected by reactive oxygen species (ROS), so suppressing mitochondrial ROS production may also be important for hibernators, just as it is important for surviving ischemia-reperfusion injury.
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Affiliation(s)
- James F Staples
- Department of Biology, University of Western Ontario, London, Ontario, Canada
| | - Katherine E Mathers
- Department of Biology, University of Western Ontario, London, Ontario, Canada
| | - Brynne M Duffy
- Department of Biology, University of Western Ontario, London, Ontario, Canada
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3
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Regan MD, Chiang E, Liu Y, Tonelli M, Verdoorn KM, Gugel SR, Suen G, Carey HV, Assadi-Porter FM. Nitrogen recycling via gut symbionts increases in ground squirrels over the hibernation season. Science 2022; 375:460-463. [PMID: 35084962 DOI: 10.1126/science.abh2950] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Hibernation is a mammalian strategy that uses metabolic plasticity to reduce energy demands and enable long-term fasting. Fasting mitigates winter food scarcity but eliminates dietary nitrogen, jeopardizing body protein balance. Here, we reveal gut microbiome-mediated urea nitrogen recycling in hibernating thirteen-lined ground squirrels (Ictidomys tridecemlineatus). Ureolytic gut microbes incorporate urea nitrogen into metabolites that are absorbed by the host, with the nitrogen reincorporated into the squirrel's protein pool. Urea nitrogen recycling is greatest after prolonged fasting in late winter, when urea transporter abundance in gut tissue and urease gene abundance in the microbiome are highest. These results reveal a functional role for the gut microbiome during hibernation and suggest mechanisms by which urea nitrogen recycling may contribute to protein balance in other monogastric animals.
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Affiliation(s)
- Matthew D Regan
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Edna Chiang
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA.,Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Yunxi Liu
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Marco Tonelli
- National Magnetic Resonance Facility at Madison (NMRFAM), University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Kristen M Verdoorn
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Sadie R Gugel
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Garret Suen
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Hannah V Carey
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Fariba M Assadi-Porter
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA.,Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
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4
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Lipid metabolism in adaptation to extreme nutritional challenges. Dev Cell 2021; 56:1417-1429. [PMID: 33730548 DOI: 10.1016/j.devcel.2021.02.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 01/11/2021] [Accepted: 02/19/2021] [Indexed: 02/06/2023]
Abstract
Food shortages represent a common challenge for most animal species. As a consequence, many have evolved metabolic strategies encompassing extreme starvation-resistance capabilities, going without food for months or even years. One such strategy is to store substantial levels of fat when food is available and release these energy-rich lipids during periods of dearth. In this review, we provide an overview of the strategies and pathways underlying the extreme capacity for animals to store and mobilize lipids during nutritionally stressful environmental conditions and highlight accompanying resilience phenotypes that allow these animals to develop and tolerate such profound metabolic phenotypes.
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5
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Bertile F, Habold C, Le Maho Y, Giroud S. Body Protein Sparing in Hibernators: A Source for Biomedical Innovation. Front Physiol 2021; 12:634953. [PMID: 33679446 PMCID: PMC7930392 DOI: 10.3389/fphys.2021.634953] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 01/12/2021] [Indexed: 12/11/2022] Open
Abstract
Proteins are not only the major structural components of living cells but also ensure essential physiological functions within the organism. Any change in protein abundance and/or structure is at risk for the proper body functioning and/or survival of organisms. Death following starvation is attributed to a loss of about half of total body proteins, and body protein loss induced by muscle disuse is responsible for major metabolic disorders in immobilized patients, and sedentary or elderly people. Basic knowledge of the molecular and cellular mechanisms that control proteostasis is continuously growing. Yet, finding and developing efficient treatments to limit body/muscle protein loss in humans remain a medical challenge, physical exercise and nutritional programs managing to only partially compensate for it. This is notably a major challenge for the treatment of obesity, where therapies should promote fat loss while preserving body proteins. In this context, hibernating species preserve their lean body mass, including muscles, despite total physical inactivity and low energy consumption during torpor, a state of drastic reduction in metabolic rate associated with a more or less pronounced hypothermia. The present review introduces metabolic, physiological, and behavioral adaptations, e.g., energetics, body temperature, and nutrition, of the torpor or hibernation phenotype from small to large mammals. Hibernating strategies could be linked to allometry aspects, the need for periodic rewarming from torpor, and/or the ability of animals to fast for more or less time, thus determining the capacity of individuals to save proteins. Both fat- and food-storing hibernators rely mostly on their body fat reserves during the torpid state, while minimizing body protein utilization. A number of them may also replenish lost proteins during arousals by consuming food. The review takes stock of the physiological, molecular, and cellular mechanisms that promote body protein and muscle sparing during the inactive state of hibernation. Finally, the review outlines how the detailed understanding of these mechanisms at play in various hibernators is expected to provide innovative solutions to fight human muscle atrophy, to better help the management of obese patients, or to improve the ex vivo preservation of organs.
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Affiliation(s)
- Fabrice Bertile
- University of Strasbourg, CNRS, IPHC UMR 7178, Laboratoire de Spectrométrie de Masse Bio-Organique, Strasbourg, France
| | - Caroline Habold
- University of Strasbourg, CNRS, IPHC UMR 7178, Ecology, Physiology & Ethology Department, Strasbourg, France
| | - Yvon Le Maho
- University of Strasbourg, CNRS, IPHC UMR 7178, Ecology, Physiology & Ethology Department, Strasbourg, France.,Centre Scientifique de Monaco, Monaco, Monaco
| | - Sylvain Giroud
- Research Institute of Wildlife Ecology, Department of Interdisciplinary Life Sciences, University of Veterinary Medicine Vienna, Vienna, Austria
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6
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Mohr SM, Bagriantsev SN, Gracheva EO. Cellular, Molecular, and Physiological Adaptations of Hibernation: The Solution to Environmental Challenges. Annu Rev Cell Dev Biol 2020; 36:315-338. [PMID: 32897760 DOI: 10.1146/annurev-cellbio-012820-095945] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Thriving in times of resource scarcity requires an incredible flexibility of behavioral, physiological, cellular, and molecular functions that must change within a relatively short time. Hibernation is a collection of physiological strategies that allows animals to inhabit inhospitable environments, where they experience extreme thermal challenges and scarcity of food and water. Many different kinds of animals employ hibernation, and there is a spectrum of hibernation phenotypes. Here, we focus on obligatory mammalian hibernators to identify the unique challenges they face and the adaptations that allow hibernators to overcome them. This includes the cellular and molecular strategies used to combat low environmental and body temperatures and lack of food and water. We discuss metabolic, neuronal, and hormonal cues that regulate hibernation and how they are thought to be coordinated by internal clocks. Last, we touch on questions that are left to be addressed in the field of hibernation research. Studies from the last century and more recent work reveal that hibernation is not simply a passive reduction in body temperature and vital parameters but rather an active process seasonally regulated at the molecular, cellular, and organismal levels.
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Affiliation(s)
- Sarah M Mohr
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA; .,Department of Neuroscience and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06510, USA;
| | - Sviatoslav N Bagriantsev
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA;
| | - Elena O Gracheva
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA; .,Department of Neuroscience and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06510, USA;
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7
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Wen X, Zhang X, Hu Y, Xu J, Wang T, Yin S. iTRAQ-based quantitative proteomic analysis of Takifugu fasciatus liver in response to low-temperature stress. J Proteomics 2019; 201:27-36. [PMID: 30954612 DOI: 10.1016/j.jprot.2019.04.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 03/25/2019] [Accepted: 04/03/2019] [Indexed: 10/27/2022]
Abstract
Low temperatures profoundly influence the physiological and behavioural processes of ectotherms, especially teleosts, which have made them the subjects of strong interest over time. However, the characteristics of fish cold-tolerance at the protein level remain unclear. Therefore, to shed further light on the molecular mechanisms of low temperature adaptation in fish, we conducted quantitative proteomics on the T. fasciatus liver using iTRAQ. Comparing the proteomic profiles of the T. fasciatus liver at 12 °C and 26 °C, a total of 3741 proteins were identified, and 160 were differentially abundant proteins (DAPs). Among the DAPs, the most significant changes were noted in proteins involved in oxidative stress (nine proteins), mitochondrial enzymes (eleven proteins) and signal transduction (thirteen proteins). The KEGG enrichment analysis indicated significant enhancement of D-arginine and D-ornithine metabolism, MAPK signalling, Wnt signalling and Gap junction pathway. Subsequently, three significantly up-regulated proteins (CIRB, HSP90 and GST) and two significantly down-regulated proteins (FLNB and A2ML1) were validated with parallel reaction monitoring (PRM) assays. Furthermore, the changes in abundance of proteins that are involved in oxidative stress, mitochondrial enzymes and signal transduction were validated at the transcriptional level with qPCR. These verification results show that the experimental data of iTRAQ are reliable. Our results not only deepen the understanding of the mechanisms underlying low-temperature tolerance in fish, but they also may contribute to the enhancement of cold tolerance during its breeding process. SIGNIFICANCE OF THE STUDY: The study focused on a comparative quantitative proteomics analysis of the T. fasciatus liver in response to low temperatures using iTRAQ, which has not yet been reported in the literatures. The results showed that the effect of low temperature on T. fasciatus is significant, including a detoxification of metabolic by-products and oxidative stress, an activation of the mitochondrial enzyme to strengthen energy metabolism, and a negative effect on signal transduction, which result in dysfunction or suboptimal performance. These low-temperature-related changes in the liver proteome of T. fasciatus can facilitate the understanding of the low temperature-related response that takes place in similar conditions in the liver and may contribute to the breeding of cold-resistant strains.
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Affiliation(s)
- Xin Wen
- College of Life Sciences, College of Marine Science and Engineering, Nanjing Normal University, Nanjing 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China
| | - Xinyu Zhang
- College of Life Sciences, College of Marine Science and Engineering, Nanjing Normal University, Nanjing 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China
| | - Yadong Hu
- College of Life Sciences, College of Marine Science and Engineering, Nanjing Normal University, Nanjing 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China
| | - Jiejie Xu
- College of Life Sciences, College of Marine Science and Engineering, Nanjing Normal University, Nanjing 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China
| | - Tao Wang
- College of Life Sciences, College of Marine Science and Engineering, Nanjing Normal University, Nanjing 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China.
| | - Shaowu Yin
- College of Life Sciences, College of Marine Science and Engineering, Nanjing Normal University, Nanjing 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China.
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8
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Gehrke S, Rice S, Stefanoni D, Wilkerson RB, Nemkov T, Reisz JA, Hansen KC, Lucas A, Cabrales P, Drew K, D'Alessandro A. Red Blood Cell Metabolic Responses to Torpor and Arousal in the Hibernator Arctic Ground Squirrel. J Proteome Res 2019; 18:1827-1841. [PMID: 30793910 DOI: 10.1021/acs.jproteome.9b00018] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Arctic ground squirrels provide a unique model to investigate metabolic responses to hibernation in mammals. During winter months these rodents are exposed to severe hypothermia, prolonged fasting, and hypoxemia. In the light of their role in oxygen transport/off-loading and owing to the absence of nuclei and organelles (and thus de novo protein synthesis capacity), mature red blood cells have evolved metabolic programs to counteract physiological or pathological hypoxemia. However, red blood cell metabolism in hibernation has not yet been investigated. Here we employed targeted and untargeted metabolomics approaches to investigate erythrocyte metabolism during entrance to torpor to arousal, with a high resolution of the intermediate time points. We report that torpor and arousal promote metabolism through glycolysis and pentose phosphate pathway, respectively, consistent with previous models of oxygen-dependent metabolic modulation in mature erythrocytes. Erythrocytes from hibernating squirrels showed up to 100-fold lower levels of biomarkers of reperfusion injury, such as the pro-inflammatory dicarboxylate succinate. Altered tryptophan metabolism during torpor was here correlated to the accumulation of potentially neurotoxic catabolites kynurenine, quinolinate, and picolinate. Arousal was accompanied by alterations of sulfur metabolism, including sudden spikes in a metabolite putatively identified as thiorphan (level 1 confidence)-a potent inhibitor of several metalloproteases that play a crucial role in nociception and inflammatory complication to reperfusion secondary to ischemia or hemorrhage. Preliminary studies in rats showed that intravenous injection of thiorphan prior to resuscitation mitigates metabolic and cytokine markers of reperfusion injury, etiological contributors to inflammatory complications after shock.
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Affiliation(s)
- Sarah Gehrke
- Department of Biochemistry and Molecular Genetics , University of Colorado Denver - Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Sarah Rice
- Department of Chemistry and Biochemistry , University of Alaska Fairbanks , Fairbanks , Alaska 99775 , United States
| | - Davide Stefanoni
- Department of Biochemistry and Molecular Genetics , University of Colorado Denver - Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Rebecca B Wilkerson
- Department of Biochemistry and Molecular Genetics , University of Colorado Denver - Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Travis Nemkov
- Department of Biochemistry and Molecular Genetics , University of Colorado Denver - Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Julie A Reisz
- Department of Biochemistry and Molecular Genetics , University of Colorado Denver - Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Kirk C Hansen
- Department of Biochemistry and Molecular Genetics , University of Colorado Denver - Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Alfredo Lucas
- Department of Bioengineering , University of California San Diego , La Jolla , California 92093 , United States
| | - Pedro Cabrales
- Department of Bioengineering , University of California San Diego , La Jolla , California 92093 , United States
| | - Kelly Drew
- Department of Chemistry and Biochemistry , University of Alaska Fairbanks , Fairbanks , Alaska 99775 , United States
| | - Angelo D'Alessandro
- Department of Biochemistry and Molecular Genetics , University of Colorado Denver - Anschutz Medical Campus , Aurora , Colorado 80045 , United States
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9
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Hibernating astronauts-science or fiction? Pflugers Arch 2018; 471:819-828. [PMID: 30569200 PMCID: PMC6533228 DOI: 10.1007/s00424-018-2244-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 11/29/2018] [Accepted: 12/03/2018] [Indexed: 12/13/2022]
Abstract
For long-duration manned space missions to Mars and beyond, reduction of astronaut metabolism by torpor, the metabolic state during hibernation of animals, would be a game changer: Water and food intake could be reduced by up to 75% and thus reducing payload of the spacecraft. Metabolic rate reduction in natural torpor is linked to profound changes in biochemical processes, i.e., shift from glycolysis to lipolysis and ketone utilization, intensive but reversible alterations in organs like the brain and kidney, and in heart rate control via Ca2+. This state would prevent degenerative processes due to organ disuse and increase resistance against radiation defects. Neuro-endocrine factors have been identified as main targets to induce torpor although the exact mechanisms are not known yet. The widespread occurrence of torpor in mammals and examples of human hypometabolic states support the idea of human torpor and its beneficial applications in medicine and space exploration.
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10
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Wiersma M, Beuren TMA, de Vrij EL, Reitsema VA, Bruintjes JJ, Bouma HR, Brundel BJJM, Henning RH. Torpor-arousal cycles in Syrian hamster heart are associated with transient activation of the protein quality control system. Comp Biochem Physiol B Biochem Mol Biol 2018; 223:23-28. [PMID: 29894736 DOI: 10.1016/j.cbpb.2018.06.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 05/28/2018] [Accepted: 06/04/2018] [Indexed: 12/14/2022]
Abstract
Hibernation consists of torpor, with marked suppression of metabolism and physiological functions, alternated with arousal periods featuring their full restoration. The heart is particularly challenged, exemplified by its rate reduction from 400 to 5-10 beats per minute during torpor in Syrian hamsters. In addition, during arousals, the heart needs to accommodate the very rapid return to normal function, which lead to our hypothesis that cardiac function during hibernation is supported by maintenance of protein homeostasis through adaptations in the protein quality control (PQC) system. Hereto, we examined autophagy, the endoplasmic reticulum (ER) unfolded protein (UPRER) response and the heat shock response (HSR) in Syrian hamster hearts during torpor and arousal. Transition from torpor to arousal (1.5 h) was associated with stimulation of the PQC system during early arousal, demonstrated by induction of autophagosomes, as shown by an increase in LC3B-II protein abundance, likely related to the activation of the UPRER during late torpor in response to proteotoxic stress. The HSR was not activated during torpor or arousal. Our results demonstrate activation of the cardiac PQC system - particularly autophagosomal degradation - in early arousal in response to cardiac stress, to clear excess aberrant or damaged proteins, being gradually formed during the torpor bout and/or the rapid increase in heart rate during the transition from torpor to arousal. This mechanism may enable the large gain in cardiac function during the transition from torpor to arousal, which may hold promise to further understand 'hibernation' of cardiomyocytes in human heart disease.
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Affiliation(s)
- Marit Wiersma
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, The Netherlands; Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, The Netherlands.
| | - Thais M A Beuren
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, The Netherlands; Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, The Netherlands
| | - Edwin L de Vrij
- Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, The Netherlands; Department of Surgery, Martini Hospital, Groningen, The Netherlands
| | - Vera A Reitsema
- Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, The Netherlands
| | - Jantje J Bruintjes
- Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, The Netherlands
| | - Hjalmar R Bouma
- Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, The Netherlands; Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Bianca J J M Brundel
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, The Netherlands; Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, The Netherlands
| | - Robert H Henning
- Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, The Netherlands
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11
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Faherty SL, Villanueva‐Cañas JL, Blanco MB, Albà MM, Yoder AD. Transcriptomics in the wild: Hibernation physiology in free‐ranging dwarf lemurs. Mol Ecol 2018; 27:709-722. [DOI: 10.1111/mec.14483] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 12/13/2017] [Accepted: 12/14/2017] [Indexed: 12/30/2022]
Affiliation(s)
| | - José Luis Villanueva‐Cañas
- Institute of Evolutionary Biology (CSIC‐Universitat Pompeu Fabra) Barcelona Spain
- Evolutionary Genomics Group Research Programme on Biomedical Informatics (GRIB) Hospital del Mar Research Institute (IMIM) Universitat Pompeu Fabra (UPF) Barcelona Spain
| | | | - M. Mar Albà
- Evolutionary Genomics Group Research Programme on Biomedical Informatics (GRIB) Hospital del Mar Research Institute (IMIM) Universitat Pompeu Fabra (UPF) Barcelona Spain
- Catalan Institution for Research and Advanced Studies (ICREA) Barcelona Spain
| | - Anne D. Yoder
- Department of Biology Duke University Durham NC USA
- Duke Lemur Center Durham NC USA
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12
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Giraud-Billoud M, Castro-Vazquez A, Campoy-Diaz AD, Giuffrida PM, Vega IA. Tolerance to hypometabolism and arousal induced by hibernation in the apple snail Pomacea canaliculata (Caenogastropoda, Ampullariidae). Comp Biochem Physiol B Biochem Mol Biol 2017; 224:129-137. [PMID: 29277604 DOI: 10.1016/j.cbpb.2017.12.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 12/06/2017] [Accepted: 12/15/2017] [Indexed: 12/30/2022]
Abstract
Pomacea canaliculata may serve as a model organism for comparative studies of oxidative damage and antioxidant defenses in active, hibernating and arousing snails. Oxidative damage (as TBARS), free radical scavenging capacity (as ABTS+ oxidation), uric acid (UA) and glutathione (GSH) concentrations, activities of superoxide dismutase (SOD) and catalase (CAT), and the protein expression levels of heat shock proteins (Hsp70, Hsc70, Hsp90) were studied in digestive gland, kidney and foot. Tissue TBARS of hibernating snails (45days) was higher than active snails. Hibernation produced an increase of ABTS+ in digestive gland, probably because of the sustained antioxidant defenses (UA and/or GSH and SOD levels). Kidney protection during the activity-hibernation cycle seemed provided by increased UA concentrations. TBARS in the foot remained high 30min after arousal with no changes in ABTS+, but this tissue increased ABTS+ oxidation at 24h to expenses increased UA and decreased GSH levels, and with no changes in SOD and CAT activities. The level of Hsp70 in kidney showed no changes throughout the activity-hibernation cycle but it increased in the foot after hibernation. The tissue levels of Hsp90 in snails hibernating were higher than active snails and returned to baseline 24h after arousal. Results showed that chronic cooling produces a significant oxidative damage in three studied tissues and that these tissue damages are overcome quickly (between 30min to 24h) with fluctuations in different antioxidant defenses (UA, GSH, CAT) and heat shock proteins (Hsp70 and Hsp90).
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Affiliation(s)
- Maximiliano Giraud-Billoud
- IHEM, Universidad Nacional de Cuyo, CONICET, Casilla de Correo 33, 5500 Mendoza, Argentina; Universidad Nacional de Cuyo, Facultad de Ciencias Médicas, Instituto de Fisiología, Casilla de Correo 33, 5500 Mendoza, Argentina.
| | - Alfredo Castro-Vazquez
- IHEM, Universidad Nacional de Cuyo, CONICET, Casilla de Correo 33, 5500 Mendoza, Argentina; Universidad Nacional de Cuyo, Facultad de Ciencias Médicas, Instituto de Fisiología, Casilla de Correo 33, 5500 Mendoza, Argentina; Universidad Nacional de Cuyo, Facultad de Ciencias Exactas y Naturales, Departamento de Biología, Casilla de Correo 33, 5500 Mendoza, Argentina
| | - Alejandra D Campoy-Diaz
- IHEM, Universidad Nacional de Cuyo, CONICET, Casilla de Correo 33, 5500 Mendoza, Argentina; Universidad Nacional de Cuyo, Facultad de Ciencias Médicas, Instituto de Fisiología, Casilla de Correo 33, 5500 Mendoza, Argentina
| | - Pablo M Giuffrida
- Universidad Nacional de Cuyo, Facultad de Ciencias Médicas, Instituto de Fisiología, Casilla de Correo 33, 5500 Mendoza, Argentina
| | - Israel A Vega
- IHEM, Universidad Nacional de Cuyo, CONICET, Casilla de Correo 33, 5500 Mendoza, Argentina; Universidad Nacional de Cuyo, Facultad de Ciencias Médicas, Instituto de Fisiología, Casilla de Correo 33, 5500 Mendoza, Argentina; Universidad Nacional de Cuyo, Facultad de Ciencias Exactas y Naturales, Departamento de Biología, Casilla de Correo 33, 5500 Mendoza, Argentina
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13
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Carey HV, Assadi-Porter FM. The Hibernator Microbiome: Host-Bacterial Interactions in an Extreme Nutritional Symbiosis. Annu Rev Nutr 2017; 37:477-500. [DOI: 10.1146/annurev-nutr-071816-064740] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Hannah V. Carey
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin 53706
| | - Fariba M. Assadi-Porter
- Department of Integrative Biology, University of Wisconsin–Madison, Madison, Wisconsin 53706
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14
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Yin Q, Zhang Y, Dong D, Lei M, Zhang S, Liao CC, Pan YH. Maintenance of neural activities in torpid Rhinolophus ferrumequinum bats revealed by 2D gel-based proteome analysis. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1865:1004-1019. [DOI: 10.1016/j.bbapap.2017.04.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 03/27/2017] [Accepted: 04/29/2017] [Indexed: 12/21/2022]
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15
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D'Alessandro A, Nemkov T, Bogren LK, Martin SL, Hansen KC. Comfortably Numb and Back: Plasma Metabolomics Reveals Biochemical Adaptations in the Hibernating 13-Lined Ground Squirrel. J Proteome Res 2016; 16:958-969. [PMID: 27991798 DOI: 10.1021/acs.jproteome.6b00884] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Hibernation is an evolutionary adaptation that affords some mammals the ability to exploit the cold to achieve extreme metabolic depression (torpor) while avoiding ischemia/reperfusion or hemorrhagic shock injuries. Hibernators cycle periodically out of torpor, restoring high metabolic activity. If understood at the molecular level, the adaptations underlying torpor-arousal cycles may be leveraged for translational applications in critical fields such as intensive care medicine. Here, we monitored 266 metabolites to investigate the metabolic adaptations to hibernation in plasma from 13-lined ground squirrels (57 animals, 9 time points). Results indicate that the periodic arousals foster the removal of potentially toxic oxidative stress-related metabolites, which accumulate in plasma during torpor while replenishing reservoirs of circulating catabolic substrates (free fatty acids and amino acids). Specifically, we identified metabolic fluctuations of basic amino acids lysine and arginine, one-carbon metabolism intermediates, and sulfur-containing metabolites methionine, cysteine, and cystathionine. Conversely, reperfusion injury markers such as succinate/fumarate remained relatively stable across cycles. Considering the cycles of these metabolites with the hibernator's cycling metabolic activity together with their well-established role as substrates for the production of hydrogen sulfide (H2S), we hypothesize that these metabolic fluctuations function as a biological clock regulating torpor to arousal transitions and resistance to reperfusion during arousal.
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Affiliation(s)
- Angelo D'Alessandro
- Department of Biochemistry and Molecular Genetics and ‡Department of Cell and Developmental Biology, University of Colorado Denver - Anschutz Medical Campus , Aurora, Colorado 80045, United States
| | - Travis Nemkov
- Department of Biochemistry and Molecular Genetics and ‡Department of Cell and Developmental Biology, University of Colorado Denver - Anschutz Medical Campus , Aurora, Colorado 80045, United States
| | - Lori K Bogren
- Department of Biochemistry and Molecular Genetics and ‡Department of Cell and Developmental Biology, University of Colorado Denver - Anschutz Medical Campus , Aurora, Colorado 80045, United States
| | - Sandra L Martin
- Department of Biochemistry and Molecular Genetics and ‡Department of Cell and Developmental Biology, University of Colorado Denver - Anschutz Medical Campus , Aurora, Colorado 80045, United States
| | - Kirk C Hansen
- Department of Biochemistry and Molecular Genetics and ‡Department of Cell and Developmental Biology, University of Colorado Denver - Anschutz Medical Campus , Aurora, Colorado 80045, United States
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16
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Arendt T, Stieler JT, Holzer M. Tau and tauopathies. Brain Res Bull 2016; 126:238-292. [DOI: 10.1016/j.brainresbull.2016.08.018] [Citation(s) in RCA: 333] [Impact Index Per Article: 41.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 08/31/2016] [Accepted: 08/31/2016] [Indexed: 12/11/2022]
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17
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Faherty SL, Villanueva-Cañas JL, Klopfer PH, Albà MM, Yoder AD. Gene Expression Profiling in the Hibernating Primate, Cheirogaleus Medius. Genome Biol Evol 2016; 8:2413-26. [PMID: 27412611 PMCID: PMC5010898 DOI: 10.1093/gbe/evw163] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2016] [Indexed: 12/24/2022] Open
Abstract
Hibernation is a complex physiological response that some mammalian species employ to evade energetic demands. Previous work in mammalian hibernators suggests that hibernation is activated not by a set of genes unique to hibernators, but by differential expression of genes that are present in all mammals. This question of universal genetic mechanisms requires further investigation and can only be tested through additional investigations of phylogenetically dispersed species. To explore this question, we use RNA-Seq to investigate gene expression dynamics as they relate to the varying physiological states experienced throughout the year in a group of primate hibernators-Madagascar's dwarf lemurs (genus Cheirogaleus). In a novel experimental approach, we use longitudinal sampling of biological tissues as a method for capturing gene expression profiles from the same individuals throughout their annual hibernation cycle. We identify 90 candidate genes that have variable expression patterns when comparing two active states (Active 1 and Active 2) with a torpor state. These include genes that are involved in metabolic pathways, feeding behavior, and circadian rhythms, as might be expected to correlate with seasonal physiological state changes. The identified genes appear to be critical for maintaining the health of an animal that undergoes prolonged periods of metabolic depression concurrent with the hibernation phenotype. By focusing on these differentially expressed genes in dwarf lemurs, we compare gene expression patterns in previously studied mammalian hibernators. Additionally, by employing evolutionary rate analysis, we find that hibernation-related genes do not evolve under positive selection in hibernating species relative to nonhibernators.
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Affiliation(s)
| | - José Luis Villanueva-Cañas
- Evolutionary Genomics Group, Research Programme on Biomedical Informatics (GRIB), Hospital del Mar Research Institute (IMIM), Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | | | - M Mar Albà
- Evolutionary Genomics Group, Research Programme on Biomedical Informatics (GRIB), Hospital del Mar Research Institute (IMIM), Universitat Pompeu Fabra (UPF), Barcelona, Spain Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
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Abstract
Extended bouts of fasting are ingrained in the ecology of many organisms, characterizing aspects of reproduction, development, hibernation, estivation, migration, and infrequent feeding habits. The challenge of long fasting episodes is the need to maintain physiological homeostasis while relying solely on endogenous resources. To meet that challenge, animals utilize an integrated repertoire of behavioral, physiological, and biochemical responses that reduce metabolic rates, maintain tissue structure and function, and thus enhance survival. We have synthesized in this review the integrative physiological, morphological, and biochemical responses, and their stages, that characterize natural fasting bouts. Underlying the capacity to survive extended fasts are behaviors and mechanisms that reduce metabolic expenditure and shift the dependency to lipid utilization. Hormonal regulation and immune capacity are altered by fasting; hormones that trigger digestion, elevate metabolism, and support immune performance become depressed, whereas hormones that enhance the utilization of endogenous substrates are elevated. The negative energy budget that accompanies fasting leads to the loss of body mass as fat stores are depleted and tissues undergo atrophy (i.e., loss of mass). Absolute rates of body mass loss scale allometrically among vertebrates. Tissues and organs vary in the degree of atrophy and downregulation of function, depending on the degree to which they are used during the fast. Fasting affects the population dynamics and activities of the gut microbiota, an interplay that impacts the host's fasting biology. Fasting-induced gene expression programs underlie the broad spectrum of integrated physiological mechanisms responsible for an animal's ability to survive long episodes of natural fasting.
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Affiliation(s)
- Stephen M Secor
- Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama, USA
| | - Hannah V Carey
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, Wisconsin, USA
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Abstract
Many environmental conditions can constrain the ability of animals to obtain sufficient food energy, or transform that food energy into useful chemical forms. To survive extended periods under such conditions animals must suppress metabolic rate to conserve energy, water, or oxygen. Amongst small endotherms, this metabolic suppression is accompanied by and, in some cases, facilitated by a decrease in core body temperature-hibernation or daily torpor-though significant metabolic suppression can be achieved even with only modest cooling. Within some ectotherms, winter metabolic suppression exceeds the passive effects of cooling. During dry seasons, estivating ectotherms can reduce metabolism without changes in body temperature, conserving energy reserves, and reducing gas exchange and its inevitable loss of water vapor. This overview explores the similarities and differences of metabolic suppression among these states within adult animals (excluding developmental diapause), and integrates levels of organization from the whole animal to the genome, where possible. Several similarities among these states are highlighted, including patterns and regulation of metabolic balance, fuel use, and mitochondrial metabolism. Differences among models are also apparent, particularly in whether the metabolic suppression is intrinsic to the tissue or depends on the whole-animal response. While in these hypometabolic states, tissues from many animals are tolerant of hypoxia/anoxia, ischemia/reperfusion, and disuse. These natural models may, therefore, serve as valuable and instructive models for biomedical research.
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Affiliation(s)
- James F Staples
- Department of Biology, University of Western Ontario, London, Ontario, Canada
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20
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Hecht AM, Braun BC, Krause E, Voigt CC, Greenwood AD, Czirják GÁ. Plasma proteomic analysis of active and torpid greater mouse-eared bats (Myotis myotis). Sci Rep 2015; 5:16604. [PMID: 26586174 PMCID: PMC4653738 DOI: 10.1038/srep16604] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 10/15/2015] [Indexed: 11/21/2022] Open
Abstract
Hibernation is a physiological adaptation to overcome extreme environmental conditions. It is characterized by prolonged periods of torpor interrupted by temporary arousals during winter. During torpor, body functions are suppressed and restored rapidly to almost pre-hibernation levels during arousal. Although molecular studies have been performed on hibernating rodents and bears, it is unclear how generalizable the results are among hibernating species with different physiology such as bats. As targeted blood proteomic analysis are lacking in small hibernators, we investigated the general plasma proteomic profile of European Myotis myotis and hibernation associated changes between torpid and active individuals by two-dimensional gel electrophoresis. Results revealed an alternation of proteins involved in transport, fuel switching, innate immunity and blood coagulation between the two physiological states. The results suggest that metabolic changes during hibernation are associated with plasma proteomic changes. Further characterization of the proteomic plasma profile identified transport proteins, coagulation proteins and complement factors and detected a high abundance of alpha-fetoprotein. We were able to establish for the first time a basic myotid bat plasma proteomic profile and further demonstrated a modulated protein expression during torpor in Myotis myotis, indicating both novel physiological pathways in bats in general, and during hibernation in particular.
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Affiliation(s)
- Alexander M. Hecht
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Straße 17, 10315 Berlin, Germany
| | - Beate C. Braun
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Straße 17, 10315 Berlin, Germany
| | - Eberhard Krause
- Leibniz Institute for Molecular Pharmacology, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Christian C. Voigt
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Straße 17, 10315 Berlin, Germany
- Department of Animal Behaviour, Freie Universität Berlin, Takustraße 3, 14195 Berlin, Germany
| | - Alex D. Greenwood
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Straße 17, 10315 Berlin, Germany
- Department of Veterinary Medicine, Freie Universität Berlin, Oertzenweg 19b, 14163 Berlin, Germany
| | - Gábor Á. Czirják
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Straße 17, 10315 Berlin, Germany
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21
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Ratigan ED, McKay DB. Exploring principles of hibernation for organ preservation. Transplant Rev (Orlando) 2015; 30:13-9. [PMID: 26613668 DOI: 10.1016/j.trre.2015.08.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 08/19/2015] [Accepted: 08/30/2015] [Indexed: 11/25/2022]
Abstract
Interest in mimicking hibernating states has led investigators to explore the biological mechanisms that permit hibernating mammals to survive for months at extremely low ambient temperatures, with no food or water, and awaken from their hibernation without apparent organ injury. Hibernators have evolved mechanisms to adapt to dramatic reductions in core body temperature and metabolic rate, accompanied by prolonged periods without nutritional intake and at the same time tolerate the metabolic demands of arousal. This review discusses the inherent resilience of hibernators to kidney injury and provides a potential framework for new therapies targeting ex vivo preservation of kidneys for transplantation.
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Affiliation(s)
- Emmett D Ratigan
- Division of Nephrology/Hypertension, Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, USA
| | - Dianne B McKay
- Division of Nephrology/Hypertension, Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, USA.
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22
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Biggar KK, Wu CW, Tessier SN, Zhang J, Pifferi F, Perret M, Storey KB. Modulation of Gene Expression in Key Survival Pathways During Daily Torpor in the Gray Mouse Lemur, Microcebus murinus. GENOMICS PROTEOMICS & BIOINFORMATICS 2015; 13:111-8. [PMID: 26093281 PMCID: PMC4511780 DOI: 10.1016/j.gpb.2015.03.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 03/20/2015] [Indexed: 12/18/2022]
Abstract
A variety of mammals employ torpor as an energy-saving strategy in environments of marginal or severe stress either on a daily basis during their inactive period or on a seasonal basis during prolonged multi-day hibernation. Recently, a few Madagascar lemur species have been identified as the only primates that exhibit torpor; one of these is the gray mouse lemur (Microcebus murinus). To explore the regulatory mechanisms that underlie daily torpor in a primate, we analyzed the expression of 28 selected genes that represent crucial survival pathways known to be involved in squirrel and bat hibernation. Array-based real-time PCR was used to compare gene expression in control (aroused) versus torpid lemurs in five tissues including the liver, kidney, skeletal muscle, heart, and brown adipose tissue. Significant differences in gene expression during torpor were revealed among genes involved in glycolysis, fatty acid metabolism, antioxidant defense, apoptosis, hypoxia signaling, and protein protection. The results showed upregulation of select genes primarily in liver and brown adipose tissue. For instance, both tissues showed elevated gene expression of peroxisome proliferator activated receptor gamma (ppargc), ferritin (fth1), and protein chaperones during torpor. Overall, the data show that the expression of only a few genes changed during lemur daily torpor, as compared with the broader expression changes reported for hibernation in ground squirrels. These results provide an indication that the alterations in gene expression required for torpor in lemurs are not as extensive as those needed for winter hibernation in squirrel models. However, identification of crucial genes with altered expression that support lemur torpor provides key targets to be explored and manipulated toward a goal of translational applications of inducible torpor as a treatment option in human biomedicine.
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Affiliation(s)
- Kyle K Biggar
- Institute of Biochemistry & Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada; Biochemistry Department, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Cheng-Wei Wu
- Institute of Biochemistry & Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada; Department of Biology, Genetics Institute, University of Florida, Gainesville, FL 32611, USA
| | - Shannon N Tessier
- Institute of Biochemistry & Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada; Department of Surgery & Center for Engineering in Medicine, Massachusetts General Hospital & Harvard Medical School, Charlestown, MA 02129, USA
| | - Jing Zhang
- Institute of Biochemistry & Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada; Chemistry and Chemical Engineering Department, Royal Military College of Canada, Kingston, ON K7K 7B4, Canada
| | - Fabien Pifferi
- UMR 7179 Centre National de la Recherche Scientifique, Muséum National d'Histoire Naturelle, 91800 Brunoy, France
| | - Martine Perret
- UMR 7179 Centre National de la Recherche Scientifique, Muséum National d'Histoire Naturelle, 91800 Brunoy, France
| | - Kenneth B Storey
- Institute of Biochemistry & Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada.
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23
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Proteomics approaches shed new light on hibernation physiology. J Comp Physiol B 2015; 185:607-27. [PMID: 25976608 DOI: 10.1007/s00360-015-0905-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 03/11/2015] [Accepted: 04/19/2015] [Indexed: 10/23/2022]
Abstract
The broad phylogenetic distribution and rapid phenotypic transitions of mammalian hibernators imply that hibernation is accomplished by differential expression of common genes. Traditional candidate gene approaches have thus far explained little of the molecular mechanisms underlying hibernation, likely due to (1) incomplete and imprecise sampling of a complex phenotype, and (2) the forming of hypotheses about which genes might be important based on studies of model organisms incapable of such dynamic physiology. Unbiased screening approaches, such as proteomics, offer an alternative means to discover the cellular underpinnings that permit successful hibernation and may reveal previously overlooked, important pathways. Here, we review the findings that have emerged from proteomics studies of hibernation. One striking feature is the stability of the proteome, especially across the extreme physiological shifts of torpor-arousal cycles during hibernation. This has led to subsequent investigations of the role of post-translational protein modifications in altering protein activity without energetically wasteful removal and rebuilding of protein pools. Another unexpected finding is the paucity of universal proteomic adjustments across organ systems in response to the extreme metabolic fluctuations despite the universality of their physiological challenges; rather each organ appears to respond in a unique, tissue-specific manner. Additional research is needed to extend and synthesize these results before it will be possible to address the whole body physiology of hibernation.
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25
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Schwartz C, Hampton M, Andrews MT. Hypothalamic gene expression underlying pre-hibernation satiety. GENES BRAIN AND BEHAVIOR 2015; 14:310-8. [PMID: 25640202 DOI: 10.1111/gbb.12199] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 12/16/2014] [Accepted: 12/22/2014] [Indexed: 11/30/2022]
Abstract
Prior to hibernation, 13-lined ground squirrels (Ictidomys tridecemlineatus) enter a hypophagic period where food consumption drops by an average of 55% in 3 weeks. This occurs naturally, while the ground squirrels are in constant environmental conditions and have free access to food. Importantly, this transition occurs before exposure to hibernation conditions (5°C and constant darkness), so the ground squirrels are still maintaining a moderate level of activity. In this study, we used the Illumina HiSeq 2000 system to sequence the hypothalamic transcriptomes of ground squirrels before and after the autumn feeding transition to examine the genes underlying this extreme change in feeding behavior. The hypothalamus was chosen because it is known to play a role in the control and regulation of food intake and satiety. Overall, our analysis identified 143 genes that are significantly differentially expressed between the two groups. Specifically, we found five genes associated with feeding behavior and obesity (VGF, TRH, LEPR, ADIPOR2, IRS2) that are all upregulated during the hypophagic period, after the feeding transition has occurred. We also found that serum leptin significantly increases in the hypophagic group. Several of the genes associated with the natural autumnal feeding decline in 13-lined ground squirrels show parallels to signaling pathways known to be disrupted in human metabolic diseases, like obesity and diabetes. In addition, many other genes were identified that could be important for the control of food consumption in other animals, including humans.
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Affiliation(s)
- C Schwartz
- Department of Biology, University of Minnesota Duluth, Duluth, MN, USA
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26
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Bogren LK, Murphy CJ, Johnston EL, Sinha N, Serkova NJ, Drew KL. 1H-NMR metabolomic biomarkers of poor outcome after hemorrhagic shock are absent in hibernators. PLoS One 2014; 9:e107493. [PMID: 25211248 PMCID: PMC4161479 DOI: 10.1371/journal.pone.0107493] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 08/12/2014] [Indexed: 11/20/2022] Open
Abstract
Background Hemorrhagic shock (HS) following trauma is a leading cause of death among persons under the age of 40. During HS the body undergoes systemic warm ischemia followed by reperfusion during medical intervention. Ischemia/reperfusion (I/R) results in a disruption of cellular metabolic processes that ultimately lead to tissue and organ dysfunction or failure. Resistance to I/R injury is a characteristic of hibernating mammals. The present study sought to identify circulating metabolites in the rat as biomarkers for metabolic alterations associated with poor outcome after HS. Arctic ground squirrels (AGS), a hibernating species that resists I/R injury independent of decreased body temperature (warm I/R), was used as a negative control. Methodology/principal findings Male Sprague-Dawley rats and AGS were subject to HS by withdrawing blood to a mean arterial pressure (MAP) of 35 mmHg and maintaining the low MAP for 20 min before reperfusing with Ringers. The animals’ temperature was maintained at 37±0.5°C for the duration of the experiment. Plasma samples were taken immediately before hemorrhage and three hours after reperfusion. Hydrophilic and lipid metabolites from plasma were then analyzed via 1H–NMR from unprocessed plasma and lipid extracts, respectively. Rats, susceptible to I/R injury, had a qualitative shift in their hydrophilic metabolic fingerprint including differential activation of glucose and anaerobic metabolism and had alterations in several metabolites during I/R indicative of metabolic adjustments and organ damage. In contrast, I/R injury resistant AGS, regardless of season or body temperature, maintained a stable metabolic homeostasis revealed by a qualitative 1H–NMR metabolic profile with few changes in quantified metabolites during HS-induced global I/R. Conclusions/significance An increase in circulating metabolites indicative of anaerobic metabolism and activation of glycolytic pathways is associated with poor prognosis after HS in rats. These same biomarkers are absent in AGS after HS with warm I/R.
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Affiliation(s)
- Lori K. Bogren
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, AK, United States of America
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, United States of America
- * E-mail:
| | - Carl J. Murphy
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, AK, United States of America
| | - Erin L. Johnston
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, AK, United States of America
| | - Neeraj Sinha
- Centre of Biomedical Research, SGPGIMS Campus, Lucknow, Uttar Pradesh, India
| | - Natalie J. Serkova
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
- University of Colorado Cancer Center, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
| | - Kelly L. Drew
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, AK, United States of America
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, United States of America
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27
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Hindle AG, Grabek KR, Epperson LE, Karimpour-Fard A, Martin SL. Metabolic changes associated with the long winter fast dominate the liver proteome in 13-lined ground squirrels. Physiol Genomics 2014; 46:348-61. [PMID: 24642758 DOI: 10.1152/physiolgenomics.00190.2013] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Small-bodied hibernators partition the year between active homeothermy and hibernating heterothermy accompanied by fasting. To define molecular events underlying hibernation that are both dependent and independent of fasting, we analyzed the liver proteome among two active and four hibernation states in 13-lined ground squirrels. We also examined fall animals transitioning between fed homeothermy and fasting heterothermy. Significantly enriched pathways differing between activity and hibernation were biased toward metabolic enzymes, concordant with the fuel shifts accompanying fasting physiology. Although metabolic reprogramming to support fasting dominated these data, arousing (rewarming) animals had the most distinct proteome among the hibernation states. Instead of a dominant metabolic enzyme signature, torpor-arousal cycles featured differences in plasma proteins and intracellular membrane traffic and its regulation. Phosphorylated NSFL1C, a membrane regulator, exhibited this torpor-arousal cycle pattern; its role in autophagosome formation may promote utilization of local substrates upon metabolic reactivation in arousal. Fall animals transitioning to hibernation lagged in their proteomic adjustment, indicating that the liver is more responsive than preparatory to the metabolic reprogramming of hibernation. Specifically, torpor use had little impact on the fall liver proteome, consistent with a dominant role of nutritional status. In contrast to our prediction of reprogramming the transition between activity and hibernation by gene expression and then within-hibernation transitions by posttranslational modification (PTM), we found extremely limited evidence of reversible PTMs within torpor-arousal cycles. Rather, acetylation contributed to seasonal differences, being highest in winter (specifically in torpor), consistent with fasting physiology and decreased abundance of the mitochondrial deacetylase, SIRT3.
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Affiliation(s)
- Allyson G Hindle
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado
| | - Katharine R Grabek
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado; Human Medical Genetics and Genomics Program, University of Colorado School of Medicine, Aurora, Colorado; and
| | - L Elaine Epperson
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado
| | - Anis Karimpour-Fard
- Center for Computational Pharmacology University of Colorado School of Medicine, Aurora, Colorado
| | - Sandra L Martin
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado; Human Medical Genetics and Genomics Program, University of Colorado School of Medicine, Aurora, Colorado; and
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Hindle AG, Martin SL. Intrinsic circannual regulation of brown adipose tissue form and function in tune with hibernation. Am J Physiol Endocrinol Metab 2014; 306:E284-99. [PMID: 24326419 PMCID: PMC3920013 DOI: 10.1152/ajpendo.00431.2013] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Winter hibernators repeatedly cycle between cold torpor and rewarming supported by nonshivering thermogenesis in brown adipose tissue (BAT). In contrast, summer animals are homeotherms, undergoing reproduction, growth, and fattening. This life history confers variability to BAT recruitment and activity. To address the components underlying prewinter enhancement and winter activation, we interrogated the BAT proteome in 13-lined ground squirrels among three summer and five winter states. We also examined mixed physiology in fall and spring individuals to test for ambient temperature and seasonal effects, as well as the timing of seasonal transitions. BAT form and function differ circannually in these animals, as evidenced by morphology and proteome dynamics. This intrinsic pattern distinguished homeothermic groups and early vs. late winter hibernators. Homeothermic variation derived from postemergence delay in growth and substrate biosynthesis. The heterothermic proteome varied less despite extreme winter physiological shifts and was optimized to exploit lipids by enhanced fatty acid binding, β-oxidation, and mitochondrial protein translocation. Surprisingly, ambient temperature did not affect the BAT proteome during transition seasons; rather, the pronounced summer-winter shift preceded environmental changes and phenotypic progression. During fall transition, differential regulation of two fatty acid binding proteins provides further evidence of recruitment and separates proteomic preparation from successful hibernation. Abundance of FABP4 correlates with torpor bout length throughout the year, clarifying its potential function in hibernation. Metabolically active BAT is a target for treating human obesity and metabolic disorders. Understanding the hibernator's extreme and seasonally distinct recruitment and activation control strategies offers untapped potential to identify novel, therapeutically relevant regulatory pathways.
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Affiliation(s)
- Allyson G Hindle
- Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado
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Zhang Y, Pan YH, Yin Q, Yang T, Dong D, Liao CC, Zhang S. Critical roles of mitochondria in brain activities of torpid Myotis ricketti bats revealed by a proteomic approach. J Proteomics 2014; 105:266-84. [PMID: 24434588 DOI: 10.1016/j.jprot.2014.01.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 12/31/2013] [Accepted: 01/04/2014] [Indexed: 01/21/2023]
Abstract
UNLABELLED Bats are the only mammals that fly and hibernate. Little is known about their overall metabolism in the brain during hibernation. In this study, brain proteins of torpid and active Myotis ricketti bats were fractionated and compared using a proteomic approach. Results showed that 21% (23 proteins) of identified proteins with significant expression changes were associated with amino acid metabolism and proteostasis. The expression levels of proteins involved in energy metabolism (15 proteins), cytoskeletal structure (18 proteins), and stress response (13 proteins) were also significantly altered in torpid bats. Over 30% (34 proteins) of differentially expressed proteins were associated with mitochondrial functions. Various post-translational modifications (PTMs) on PDHB, DLD, and ARG1 were detected, suggesting that bats use PTMs to regulate protein functions during torpor. Antioxidation and stress responses in torpid bats were similar to those of hibernated squirrels, suggesting a common strategy adopted by small hibernators against brain dysfunction. Since many amino acids that metabolize in mitochondria modulate neuronal transmissions, results of this study reveal pivotal roles of mitochondria in neural communication, metabolic regulation, and brain cell survival during bat hibernation. This article is part of a Special Issue entitled: Proteomics of non-model organisms. BIOLOGICAL SIGNIFICANCE This study reveals the mechanisms used by bats to regulate brain activities during torpor. These mechanisms include post-translational modifications and differential expression of proteins involved in mitochondrial electron transport, anaerobic glycolysis, TCA cycle efflux, cytoskeletal plasticity, amino acid metabolism, vesicle structure, antioxidation defense, stress response, and proteostasis. Our study provides insights in metabolic regulation of flying mammals during torpor and common strategies used by small hibernators in response to hibernation. This article is part of a Special Issue entitled: Proteomics of non-model organisms.
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Affiliation(s)
- Yijian Zhang
- Laboratory of Molecular Ecology and Evolution, Institute for Advanced Studies in Multidisciplinary Science and Technology, East China Normal University, Shanghai 200062, China
| | - Yi-Hsuan Pan
- Laboratory of Molecular Ecology and Evolution, Institute for Advanced Studies in Multidisciplinary Science and Technology, East China Normal University, Shanghai 200062, China
| | - Qiuyuan Yin
- Laboratory of Molecular Ecology and Evolution, Institute for Advanced Studies in Multidisciplinary Science and Technology, East China Normal University, Shanghai 200062, China
| | - Tianxiao Yang
- Laboratory of Molecular Ecology and Evolution, Institute for Advanced Studies in Multidisciplinary Science and Technology, East China Normal University, Shanghai 200062, China
| | - Dong Dong
- Laboratory of Molecular Ecology and Evolution, Institute for Advanced Studies in Multidisciplinary Science and Technology, East China Normal University, Shanghai 200062, China
| | - Chen-Chung Liao
- Proteomic Research Center, National Yang-Ming University, Taipei 11221, Taiwan.
| | - Shuyi Zhang
- Laboratory of Molecular Ecology and Evolution, Institute for Advanced Studies in Multidisciplinary Science and Technology, East China Normal University, Shanghai 200062, China.
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Nagasawa K, Tanizaki Y, Okui T, Watarai A, Ueda S, Kato T. Significant modulation of the hepatic proteome induced by exposure to low temperature in Xenopus laevis. Biol Open 2013; 2:1057-69. [PMID: 24167716 PMCID: PMC3798189 DOI: 10.1242/bio.20136106] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Accepted: 07/22/2013] [Indexed: 01/24/2023] Open
Abstract
The African clawed frog, Xenopus laevis, is an ectothermic vertebrate that can survive at low environmental temperatures. To gain insight into the molecular events induced by low body temperature, liver proteins were evaluated at the standard laboratory rearing temperature (22°C, control) and a low environmental temperature (5°C, cold exposure). Using nano-flow liquid chromatography coupled with tandem mass spectrometry, we identified 58 proteins that differed in abundance. A subsequent Gene Ontology analysis revealed that the tyrosine and phenylalanine catabolic processes were modulated by cold exposure, which resulted in decreases in hepatic tyrosine and phenylalanine, respectively. Similarly, levels of pyruvate kinase and enolase, which are involved in glycolysis and glycogen synthesis, were also decreased, whereas levels of glycogen phosphorylase, which participates in glycogenolysis, were increased. Therefore, we measured metabolites in the respective pathways and found that levels of hepatic glycogen and glucose were decreased. Although the liver was under oxidative stress because of iron accumulation caused by hepatic erythrocyte destruction, the hepatic NADPH/NADP ratio was not changed. Thus, glycogen is probably utilized mainly for NADPH supply rather than for energy or glucose production. In conclusion, X. laevis responds to low body temperature by modulating its hepatic proteome, which results in altered carbohydrate metabolism.
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Affiliation(s)
- Kazumichi Nagasawa
- Department of Integrative Bioscience and Biomedical Engineering, Graduate School of Advanced Science and Engineering, Center for Advanced Life and Medical Science, Waseda University , TWIns Building, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480 , Japan
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31
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Wu CW, Biggar KK, Storey KB. Dehydration mediated microRNA response in the African clawed frog Xenopus laevis. Gene 2013; 529:269-75. [PMID: 23958654 DOI: 10.1016/j.gene.2013.07.064] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 07/11/2013] [Accepted: 07/17/2013] [Indexed: 12/24/2022]
Abstract
Exposure to various environmental stresses induces metabolic rate depression in many animal species, an adaptation that conserves energy until the environment is again conducive to normal life. The African clawed frog, Xenopus laevis, is periodically subjected to arid summers in South Africa, and utilizes entry into the hypometabolic state of estivation as a mechanism of long term survival. During estivation, frogs must typically deal with substantial dehydration as their ponds dry out and X. laevis can endure >30% loss of its body water. We hypothesize that microRNAs play a vital role in establishing a reversible hypometabolic state and responding to dehydration stress that is associated with amphibian estivation. The present study analyzes the effects of whole body dehydration on microRNA expression in three tissues of X. laevis. Compared to controls, levels of miR-1, miR-125b, and miR-16-1 decreased to 37±6, 64±8, and 80±4% of control levels during dehydration in liver. By contrast, miR-210, miR-34a and miR-21 were significantly elevated by 3.05±0.45, 2.11±0.08, and 1.36±0.05-fold, respectively, in the liver. In kidney tissue, miR-29b, miR-21, and miR-203 were elevated by 1.40±0.09, 1.31±0.05, and 2.17±0.31-fold, respectively, in response to dehydration whereas miR-203 and miR-34a were elevated in ventral skin by 1.35±0.05 and 1.74±0.12-fold, respectively. Bioinformatic analysis of the differentially expressed microRNAs suggests that these are mainly involved in two processes: (1) expression of solute carrier proteins, and (2) regulation of mitogen-activated protein kinase signaling. This study is the first report that shows a tissue specific mode of microRNA expression during amphibian dehydration, providing evidence for microRNAs as crucial regulators of metabolic depression.
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Affiliation(s)
- Cheng-Wei Wu
- Institute of Biochemistry and Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
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32
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Hindle AG, Martin SL. Cytoskeletal regulation dominates temperature-sensitive proteomic changes of hibernation in forebrain of 13-lined ground squirrels. PLoS One 2013; 8:e71627. [PMID: 23951209 PMCID: PMC3739743 DOI: 10.1371/journal.pone.0071627] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 07/01/2013] [Indexed: 12/17/2022] Open
Abstract
13-lined ground squirrels, Ictidomys tridecemlineatus, are obligate hibernators that transition annually between summer homeothermy and winter heterothermy – wherein they exploit episodic torpor bouts. Despite cerebral ischemia during torpor and rapid reperfusion during arousal, hibernator brains resist damage and the animals emerge neurologically intact each spring. We hypothesized that protein changes in the brain underlie winter neuroprotection. To identify candidate proteins, we applied a sensitive 2D gel electrophoresis method to quantify protein differences among forebrain extracts prepared from ground squirrels in two summer, four winter and fall transition states. Proteins that differed among groups were identified using LC-MS/MS. Only 84 protein spots varied significantly among the defined states of hibernation. Protein changes in the forebrain proteome fell largely into two reciprocal patterns with a strong body temperature dependence. The importance of body temperature was tested in animals from the fall; these fall animals use torpor sporadically with body temperatures mirroring ambient temperatures between 4 and 21°C as they navigate the transition between summer homeothermy and winter heterothermy. Unlike cold-torpid fall ground squirrels, warm-torpid individuals strongly resembled the homeotherms, indicating that the changes observed in torpid hibernators are defined by body temperature, not torpor per se. Metabolic enzymes were largely unchanged despite varied metabolic activity across annual and torpor-arousal cycles. Instead, the majority of the observed changes were cytoskeletal proteins and their regulators. While cytoskeletal structural proteins tended to differ seasonally, i.e., between summer homeothermy and winter heterothermy, their regulatory proteins were more strongly affected by body temperature. Changes in the abundance of various isoforms of the microtubule assembly and disassembly regulatory proteins dihydropyrimidinase-related protein and stathmin suggested mechanisms for rapid cytoskeletal reorganization on return to euthermy during torpor-arousal cycles.
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Affiliation(s)
- Allyson G Hindle
- Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado, USA.
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33
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Chow BA, Donahue SW, Vaughan MR, McConkey B, Vijayan MM. Serum immune-related proteins are differentially expressed during hibernation in the American black bear. PLoS One 2013; 8:e66119. [PMID: 23825529 PMCID: PMC3692520 DOI: 10.1371/journal.pone.0066119] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 05/01/2013] [Indexed: 11/23/2022] Open
Abstract
Hibernation is an adaptation to conserve energy in the face of extreme environmental conditions and low food availability that has risen in several animal phyla. This phenomenon is characterized by reduced metabolic rate (∼25% of the active basal metabolic rate in hibernating bears) and energy demand, while other physiological adjustments are far from clear. The profiling of the serum proteome of the American black bear (Ursus americanus) may reveal specific proteins that are differentially modulated by hibernation, and provide insight into the remarkable physiological adaptations that characterize ursid hibernation. In this study, we used differential gel electrophoresis (DIGE) analysis, liquid chromatography coupled to tandem mass spectrometry, and subsequent MASCOT analysis of the mass spectra to identify candidate proteins that are differentially expressed during hibernation in captive black bears. Seventy serum proteins were identified as changing by ±1.5 fold or more, out of which 34 proteins increased expression during hibernation. The majority of identified proteins are involved in immune system processes. These included α2-macroglobulin, complement components C1s and C4, immunoglobulin μ and J chains, clusterin, haptoglobin, C4b binding protein, kininogen 1, α2-HS-glycoprotein, and apoplipoproteins A-I and A-IV. Differential expression of a subset of these proteins identified by proteomic analysis was also confirmed by immunodetection. We propose that the observed serum protein changes contribute to the maintenance of the hibernation phenotype and health, including increased capacities for bone maintenance and wound healing during hibernation in bears.
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Affiliation(s)
- Brian A. Chow
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Seth W. Donahue
- Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado, United States of America
| | - Michael R. Vaughan
- Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Brendan McConkey
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
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34
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Pan YH, Zhang Y, Cui J, Liu Y, McAllan BM, Liao CC, Zhang S. Adaptation of phenylalanine and tyrosine catabolic pathway to hibernation in bats. PLoS One 2013; 8:e62039. [PMID: 23620802 PMCID: PMC3631164 DOI: 10.1371/journal.pone.0062039] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 02/24/2013] [Indexed: 11/19/2022] Open
Abstract
Some mammals hibernate in response to harsh environments. Although hibernating mammals may metabolize proteins, the nitrogen metabolic pathways commonly activated during hibernation are not fully characterized. In contrast to the hypothesis of amino acid preservation, we found evidence of amino acid metabolism as three of five key enzymes, including phenylalanine hydroxylase (PAH), homogentisate 1,2-dioxygenase (HGD), fumarylacetoacetase (FAH), involved in phenylalanine and tyrosine catabolism were co-upregulated during hibernation in two distantly related species of bats, Myotis ricketti and Rhinolophus ferrumequinum. In addition, the levels of phenylalanine in the livers of these bats were significantly decreased during hibernation. Because phenylalanine and tyrosine are both glucogenic and ketogenic, these results indicate the role of this catabolic pathway in energy supply. Since any deficiency in the catabolism of these two amino acids can cause accumulations of toxic metabolites, these results also suggest the detoxification role of these enzymes during hibernation. A higher selective constraint on PAH, HPD, and HGD in hibernators than in non-hibernators was observed, and hibernators had more conserved amino acid residues in each of these enzymes than non-hibernators. These conserved amino acid residues are mostly located in positions critical for the structure and activity of the enzymes. Taken together, results of this work provide novel insights in nitrogen metabolism and removal of harmful metabolites during bat hibernation.
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Affiliation(s)
- Yi-Hsuan Pan
- Laboratory of Molecular Ecology and Evolution, Institute for Advanced Studies in Multidisciplinary Science and Technology, East China Normal University, Shanghai, China
| | - Yijian Zhang
- Laboratory of Molecular Ecology and Evolution, Institute for Advanced Studies in Multidisciplinary Science and Technology, East China Normal University, Shanghai, China
| | - Jie Cui
- Laboratory of Molecular Ecology and Evolution, Institute for Advanced Studies in Multidisciplinary Science and Technology, East China Normal University, Shanghai, China
| | - Yang Liu
- Laboratory of Molecular Ecology and Evolution, Institute for Advanced Studies in Multidisciplinary Science and Technology, East China Normal University, Shanghai, China
| | - Bronwyn M. McAllan
- Discipline of Physiology and Bosch Institute, School of Medical Science, The University of Sydney, Sydney, New South Wales, Australia
| | - Chen-Chung Liao
- Proteomic Research Center, National Yang-Ming University, Taipei, Taiwan
- * E-mail: (SZ); (CL)
| | - Shuyi Zhang
- Laboratory of Molecular Ecology and Evolution, Institute for Advanced Studies in Multidisciplinary Science and Technology, East China Normal University, Shanghai, China
- * E-mail: (SZ); (CL)
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35
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Kolomiytseva IK, Perepelkina NI, Fesenko EE. Lipids of liver membrane structures during hibernation of the arctic ground squirrel Spermophilus undulatus. DOKL BIOCHEM BIOPHYS 2013; 448:15-8. [PMID: 23478979 DOI: 10.1134/s1607672913010055] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Indexed: 11/23/2022]
Affiliation(s)
- I K Kolomiytseva
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow oblast, Russia
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36
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Schwartz C, Andrews MT. Circannual transitions in gene expression: lessons from seasonal adaptations. Curr Top Dev Biol 2013; 105:247-73. [PMID: 23962845 DOI: 10.1016/b978-0-12-396968-2.00009-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Circannual timing is important for the coordination of seasonal activities, particularly promoting the survival of individuals in adverse conditions through adaptive physiological and behavioral changes. This includes optimizing the survival of offspring by coordinating reproductive efforts at appropriate times. Thus, timing is very important for overall fitness. In this chapter, we provide several examples of circannually timed events, including mammalian hibernation, discussing the physiological changes that accompany these events, and some of the known genes and pathways underlying these changes. We then describe five candidate systems that are potentially involved in circannual timing. Finally, we discuss several recent advances in molecular biology and animal husbandry that have made the use of nonmodel organisms for research more feasible, which will hopefully promote and encourage further advancement in the knowledge of circannual timing.
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Affiliation(s)
- Christine Schwartz
- Department of Biology, University of Minnesota Duluth, Duluth, Minnesota, USA
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37
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Oda T, Shimizu K, Yamaguchi A, Satoh K, Matsumoto KI. Hypothermia produces rat liver proteomic changes as in hibernating mammals but decreases endoplasmic reticulum chaperones. Cryobiology 2012; 65:104-12. [DOI: 10.1016/j.cryobiol.2012.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 04/24/2012] [Accepted: 05/10/2012] [Indexed: 12/25/2022]
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Jani A, Orlicky DJ, Karimpour-Fard A, Epperson LE, Russell RL, Hunter LE, Martin SL. Kidney proteome changes provide evidence for a dynamic metabolism and regional redistribution of plasma proteins during torpor-arousal cycles of hibernation. Physiol Genomics 2012; 44:717-27. [PMID: 22643061 DOI: 10.1152/physiolgenomics.00010.2012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Hibernating ground squirrels maintain homeostasis despite extreme physiological challenges. In winter, these circannual hibernators fast for months while cycling between prolonged periods of low blood flow and body temperature, known as torpor, and short interbout arousals (IBA), where more typical mammalian parameters are rapidly restored. Here we examined the kidney proteome for changes that support the dramatically different physiological demands of the hibernator's year. We identified proteins in 150 two-dimensional gel spots that altered by at least 1.5-fold using liquid chromatography and tandem mass spectrometry. These data successfully classified individuals by physiological state and revealed three dynamic patterns of relative protein abundance that dominated the hibernating kidney: 1) a large group of proteins generally involved with capturing and storing energy were most abundant in summer; 2) a select subset of these also increased during each arousal from torpor; and 3) 14 spots increased in torpor and early arousal were enriched for plasma proteins that enter cells via the endocytic pathway. Immunohistochemistry identified α(2)-macroglobulin and albumin in kidney blood vessels during late torpor and early arousal; both exhibited regional heterogeneity consistent with highly localized control of blood flow in the glomeruli. Furthermore, albumin, but not α(2)-macroglobulin, was detected in the proximal tubules during torpor and early arousal but not in IBA or summer animals. Taken together, our findings indicate that normal glomerular filtration barriers remain intact throughout torpor-arousal cycles but endocytosis, and hence renal function, is compromised at low body temperature during torpor and then recovers with rewarming during arousal.
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Affiliation(s)
- Alkesh Jani
- Division of Renal Diseases and Hypertension, University of Colorado School of Medicine, Aurora, CO 80045, USA
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39
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Peck LS. Organisms and responses to environmental change. Mar Genomics 2011; 4:237-43. [DOI: 10.1016/j.margen.2011.07.001] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 07/06/2011] [Accepted: 07/08/2011] [Indexed: 11/24/2022]
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Grabek KR, Karimpour-Fard A, Epperson LE, Hindle A, Hunter LE, Martin SL. Multistate proteomics analysis reveals novel strategies used by a hibernator to precondition the heart and conserve ATP for winter heterothermy. Physiol Genomics 2011; 43:1263-75. [PMID: 21914784 PMCID: PMC3217319 DOI: 10.1152/physiolgenomics.00125.2011] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Accepted: 09/02/2011] [Indexed: 11/22/2022] Open
Abstract
The hibernator's heart functions continuously and avoids damage across the wide temperature range of winter heterothermy. To define the molecular basis of this phenotype, we quantified proteomic changes in the 13-lined ground squirrel heart among eight distinct physiological states encompassing the hibernator's year. Unsupervised clustering revealed a prominent seasonal separation between the summer homeotherms and winter heterotherms, whereas within-season state separation was limited. Further, animals torpid in the fall were intermediate to summer and winter, consistent with the transitional nature of this phase. A seasonal analysis revealed that the relative abundances of protein spots were mainly winter-increased. The winter-elevated proteins were involved in fatty acid catabolism and protein folding, whereas the winter-depleted proteins included those that degrade branched-chain amino acids. To identify further state-dependent changes, protein spots were re-evaluated with respect to specific physiological state, confirming the predominance of seasonal differences. Additionally, chaperone and heat shock proteins increased in winter, including HSPA4, HSPB6, and HSP90AB1, which have known roles in protecting against ischemia-reperfusion injury and apoptosis. The most significant and greatest fold change observed was a disappearance of phospho-cofilin 2 at low body temperature, likely a strategy to preserve ATP. The robust summer-to-winter seasonal proteomic shift implies that a winter-protected state is orchestrated before prolonged torpor ensues. Additionally, the general preservation of the proteome during winter hibernation and an increase of stress response proteins, together with dephosphorylation of cofilin 2, highlight the importance of ATP-conserving mechanisms for winter cardioprotection.
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Affiliation(s)
- Katharine R Grabek
- Human Medical Genetics Program, Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
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41
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Hindle AG, Karimpour-Fard A, Epperson LE, Hunter LE, Martin SL. Skeletal muscle proteomics: carbohydrate metabolism oscillates with seasonal and torpor-arousal physiology of hibernation. Am J Physiol Regul Integr Comp Physiol 2011; 301:R1440-52. [PMID: 21865542 PMCID: PMC3213940 DOI: 10.1152/ajpregu.00298.2011] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 08/22/2011] [Indexed: 02/07/2023]
Abstract
The physiology of small mammalian hibernators shifts profoundly over a year, from summer homeothermy to winter heterothermy. Torpor-arousal cycles define high-amplitude tissue activity fluctuations in winter, particularly for skeletal muscle, which contributes to the energetically demanding rewarming process via shivering. To better understand the biochemistry underlying summer-winter and torpor-arousal transitions, we applied two-dimensional gel electrophoresis coupled with liquid chromatography/mass spectrometry/mas spectrometry to the soluble proteins from hindlimb muscle of 13-lined ground squirrels (Ictidomys tridecemlineatus) in two summer and six winter states. Two hundred sixteen protein spots differed by sampled state. Significantly, intrawinter protein adjustment was a minor component of the dataset despite large discrepancies in muscle activity level among winter states; rather, the bulk of differences (127/138 unequivocally identified proteins spots) occurred between summer and winter. We did not detect any proteomic signatures of skeletal muscle atrophy in this hibernator nor any differential seasonal regulation of protein metabolism. Instead, adjustments to metabolic substrate preferences dominated the detected proteomic differences. Pathways of carbohydrate metabolism (glycolysis and gluconeogenesis) were summer enriched, whereas the winter proteome was enriched for fatty acid β-oxidation. Nevertheless, our data suggest that some reliance on carbohydrate reserves is maintained during winter. Phosphoglucomutase (PGM1), which reversibly prepares glucose subunits for either glycolysis or glycogenesis, showed apparent winter state-specific phosphorylation. PGM1 was phosphorylated during rewarming and dephosphorylated by interbout arousal, implying that glucose supplements lipid fuels during rewarming. This, along with winter elevation of TCA cycle enzymes, suggests that hindlimb muscles are primed for rapid energy production and that carbohydrates are an important fuel for shivering thermogenesis.
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Affiliation(s)
- Allyson G Hindle
- Dept. of Cell and Developmental Biology, PO Box 6511, MS 8010, Univ. of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO 80045, USA.
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Williams CT, Goropashnaya AV, Buck CL, Fedorov VB, Kohl F, Lee TN, Barnes BM. Hibernating above the permafrost: effects of ambient temperature and season on expression of metabolic genes in liver and brown adipose tissue of arctic ground squirrels. ACTA ACUST UNITED AC 2011; 214:1300-6. [PMID: 21430207 DOI: 10.1242/jeb.052159] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Hibernating arctic ground squirrels (Urocitellus parryii), overwintering in frozen soils, maintain large gradients between ambient temperature (T(a)) and body temperature (T(b)) by substantially increasing metabolic rate during torpor while maintaining a subzero T(b). We used quantitative reverse-transcription PCR (qRT-PCR) to determine how the expression of 56 metabolic genes was affected by season (active in summer vs hibernating), metabolic load during torpor (imposed by differences in T(a): +2 vs -10°C) and hibernation state (torpid vs after arousal). Compared with active ground squirrels sampled in summer, liver from hibernators showed increased expression of genes associated with fatty acid catabolism (CPT1A, FABP1 and ACAT1), ketogenesis (HMGCS2) and gluconeogenesis (PCK1) and decreased expression of genes associated with fatty acid synthesis (ACACB, SCD and ELOVL6), amino acid metabolism, the urea cycle (PAH, BCKDHA and OTC), glycolysis (PDK1 and PFKM) and lipid metabolism (ACAT2). Stage of hibernation (torpid vs aroused) had a much smaller effect, with only one gene associated with glycogen synthesis (GSY1) in liver showing consistent differences in expression levels between temperature treatments. Despite the more than eightfold increase in energetic demand associated with defending T(b) during torpor at a T(a) of -10 vs +2°C, transcript levels in liver and brown adipose tissue differed little. Our results are inconsistent with a hypothesized switch to use of non-lipid fuels when ambient temperatures drop below freezing.
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Affiliation(s)
- Cory T Williams
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775-7000, USA
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Epperson LE, Karimpour-Fard A, Hunter LE, Martin SL. Metabolic cycles in a circannual hibernator. Physiol Genomics 2011; 43:799-807. [PMID: 21540299 DOI: 10.1152/physiolgenomics.00028.2011] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Hibernation as manifested in ground squirrels is arguably the most plastic and extreme of physiological phenotypes in mammals. Homeostasis is challenged by prolonged fasting accompanied by heterothermy, yet must be facilitated for survival. We performed LC and GC-MS metabolomic profiling of plasma samples taken reproducibly during seven natural stages of the hibernator's year, three in summer and four in winter (each n ≥ 5), employing a nontargeted approach to define the metabolite shifts associated with the phenotype. We quantified 231 named metabolites; 106 of these altered significantly, demarcating a cycle within a cycle where torpor-arousal cycles recur during the winter portion of the seasonal cycle. A number of robust hibernation biomarkers that alter with season and winter stage are identified, including specific free fatty acids, antioxidants, and previously unpublished modified amino acids that are likely to be associated with the fasting state. The major pattern in metabolite levels is one of either depletion or accrual during torpor, followed by reversal to an apparent homeostatic level by interbout arousal. This finding provides new data that strongly support the predictions of a long-standing hypothesis that periodic arousals are necessary to restore metabolic homeostasis.
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Affiliation(s)
- L Elaine Epperson
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado, USA
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44
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Rose JC, Epperson LE, Carey HV, Martin SL. Seasonal liver protein differences in a hibernator revealed by quantitative proteomics using whole animal isotopic labeling. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2011; 6:163-70. [PMID: 21481655 DOI: 10.1016/j.cbd.2011.02.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 02/17/2011] [Accepted: 02/26/2011] [Indexed: 11/29/2022]
Abstract
Hibernation is an energy-saving strategy used by diverse species of mammals to survive winter. It is characterized by cycles between multi-day periods of torpor with low body temperature (T(b)), and short periods of rapid, spontaneous rewarming. The ability to retain cellular integrity and function throughout torpor and rewarming is a key attribute of hibernation. Livers from winter hibernators are resistant to cellular damage induced by cold storage followed by warm reperfusion. Identifying proteins that differ between the summer-sensitive and winter-protected phenotypic states is one useful approach that may elucidate the molecular mechanisms that underlie this protection. Here we employ a novel quantitative proteomics screening strategy whereby a newly-weaned 13-lined ground squirrel was metabolically labeled by ingesting heavy-isotope substituted ((15)N) Spirulina. The liver protein extract from this animal provided a common reference for quantitative evaluation of protein differences by its addition to extracts from pooled samples of summer active (SA) or winter entrance (Ent) phase hibernating ground squirrels. We identified 61 significantly different proteins between the two groups and compared them to proteins identified previously in the same samples using 2D gels. Of the 20 proteins common to the two datasets, the direction and magnitude of their differences were perfectly concordant for 18, providing confidence that both sets of altered proteins reflect bona fide differences between the two physiological states. Furthermore, the 41 novel proteins recovered in this study included many new enzymes in pathways identified previously: specifically, additional enzymes belonging to the urea cycle, amino acid and carbohydrate degradation, and lipid biosynthetic pathways were decreased, whereas enzymes involved in ketone body synthesis, fatty acid utilization, protein synthesis and gluconeogenesis were increased in the samples from entrance hibernators compared to summer active animals, providing additional specific evidence for the importance of these pathways in the hibernating phenotype.
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Affiliation(s)
- J Cameron Rose
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, 80045, USA
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45
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Zhao Z, Miki T, Van Oort-Jansen A, Matsumoto T, Loose DS, Lee CC. Hepatic gene expression profiling of 5'-AMP-induced hypometabolism in mice. Physiol Genomics 2011; 43:325-45. [PMID: 21224422 DOI: 10.1152/physiolgenomics.00174.2010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
There is currently much interest in clinical applications of therapeutic hypothermia. Hypothermia can be a consequence of hypometabolism. We have recently established a procedure for the induction of a reversible deep hypometabolic state in mice using 5'-adenosine monophosphate (5'-AMP) in conjunction with moderate ambient temperature. The current study aims at investigating the impact of this technology at the gene expression level in a major metabolic organ, the liver. Our findings reveal that expression levels of the majority of genes in liver are not significantly altered by deep hypometabolism. However, among those affected by hypometabolism, more genes are differentially upregulated than downregulated both in a deep hypometabolic state and in the early arousal state. These altered gene expression levels during 5'-AMP induced hypometabolism are largely restored to normal levels within 2 days of the treatment. Our data also suggest that temporal control of circadian genes is largely stalled during deep hypometabolism.
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Affiliation(s)
- Zhaoyang Zhao
- Department of Biochemistry, UTHealth Medical School, Houston, Texas 77030, USA.
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46
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Nelson CJ, Otis JP, Carey HV. Global analysis of circulating metabolites in hibernating ground squirrels. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2010; 5:265-73. [PMID: 20728417 DOI: 10.1016/j.cbd.2010.07.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Revised: 07/19/2010] [Accepted: 07/21/2010] [Indexed: 11/28/2022]
Abstract
Hibernation in mammals involves major alterations in nutrition and metabolism that would be expected to affect levels of circulating molecules. To gain insight into these changes we conducted a non-targeted LC-MS based metabolomic analysis of plasma using hibernating ground squirrels in late torpor (LT, T(b)~5 °C) or during an interbout arousal period (IBA, T(b)~5 °C) and non-hibernating squirrels in spring (T(b)~37 °C). Several metabolites varied and allowed differentiation between hibernators and spring squirrels, and between torpid and euthermic squirrels. Methionine and the short-chain carnitine esters of propionate and butyryate/isobutyrate were reduced in LT compared with the euthermic groups. Pantothenic acid and several lysophosphatidylcholines were elevated in LT relative to the euthermic groups, whereas lysophosphatidylethanolamines were elevated during IBA compared to LT and spring animals. Two regulatory lipids varied among the groups: sphingosine 1-phosphate was lower in LT vs. euthermic groups, whereas cholesterol sulfate was elevated in IBA compared to spring squirrels. Levels of long-chain fatty acids (LCFA) and total NEFA tended to be elevated in hibernators relative to spring squirrels. Three long-chain acylcarnitines were reduced in LT relative to IBA; free carnitine was also lower in LT vs. IBA. Our results identified several biochemical changes not previously observed in the seasonal hibernation cycle, including some that may provide insight into the metabolic limitations of mammalian torpor.
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Affiliation(s)
- Clark J Nelson
- Department of Comparative Biosciences, University of Wisconsin School of Veterinary Medicine, Madison, WI 53706, USA
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Russell RL, O'Neill PH, Epperson LE, Martin SL. Extensive use of torpor in 13-lined ground squirrels in the fall prior to cold exposure. J Comp Physiol B 2010; 180:1165-72. [PMID: 20556614 DOI: 10.1007/s00360-010-0484-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 05/24/2010] [Accepted: 05/26/2010] [Indexed: 11/24/2022]
Abstract
Mammalian hibernation is characterized by profound reductions in body temperature (T(b)) and metabolic, heart and respiratory rates. These reductions are characteristic of torpor, which is temporally confined to winter. Hibernators including ground squirrels are heterothermic in winter, cycling between multiday periods of torpor with low T(b) and brief periods of rewarming. In contrast, ground squirrels remain homeothermic during summer, like non-hibernating mammals. The transition between the homeothermic and heterothermic phases of the circannual rhythm of hibernation is often overlooked in hibernation studies. Here, we examined the use of torpor throughout the fall transition in laboratory-housed 13-lined ground squirrels by recording core body temperature with an implanted data logger. As is typical of laboratory-based hibernation studies, animals were kept in standard housing prior to being moved into a cold, dark room to simulate natural hibernation conditions. Significantly, the vast majority of both male and female ground squirrels expressed torpor in the fall while still housed conventionally and prior to cold exposure. The expression of torpor was not predicted by body weight or age, rather it appears to be preprogrammed in a time-dependent manner that is independent of, yet enhanced by, environmental cues. The timing and duration of these torpor bouts occurring prior to cold exposure were also remarkably sporadic. Thus, it is not possible to know with certainty which animals are torpor-naive before cold exposure in the absence of continuous measurement of body temperature. We conclude that fall animals encompass variable points in the transition between summer and winter phases of the circannual cycle of hibernation, thereby confounding studies in which they are used as non-hibernating controls. Conversely, these fall transition animals offer unique opportunities to define the molecular changes that accompany and enable hibernation.
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Affiliation(s)
- Rae L Russell
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, P.O. Box 6511, MS 8108, Aurora, CO 80045, USA
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48
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Epperson LE, Rose JC, Russell RL, Nikrad MP, Carey HV, Martin SL. Seasonal protein changes support rapid energy production in hibernator brainstem. J Comp Physiol B 2009; 180:599-617. [PMID: 19967378 DOI: 10.1007/s00360-009-0422-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Revised: 10/26/2009] [Accepted: 11/03/2009] [Indexed: 01/03/2023]
Abstract
During the torpor phase of mammalian hibernation when core body temperature is near 4 degrees C, the autonomic system continues to maintain respiration, blood pressure and heartbeat despite drastic reductions in brain activity. In addition, the hibernator's neuronal tissues enter into a protected state in which the potential for ischemia-reperfusion injury is markedly minimized. Evolutionary adaptations for continued function and neuroprotection throughout cycles of torpor and euthermia in winter are predicted to manifest themselves partly in changes in the brainstem proteome. Here, we compare the soluble brainstem protein complement from six summer active ground squirrels and six in the early torpor (ET) phase of hibernation. Thirteen percent of the approximately 1,500 quantifiable 2D gel spots alter significantly from summer to ET; the proteins identified in these differing spots are known to play roles in energy homeostasis via the tricarboxylic acid cycle (8 proteins), cytoarchitecture and cell motility (14 proteins), anabolic protein processes (13 proteins), redox control (11 proteins) and numerous other categories including protein catabolism, oxidative phosphorylation, signal transduction, glycolysis, intracellular protein trafficking and antiapoptotic function. These protein changes represent, at least in part, the molecular bases for restructuring of cells in the brainstem, a shift away from glucose as the primary fuel source for brain in the winter, and the generation of a streamlined mechanism capable of efficient and rapid energy production and utilization during the torpor and arousal cycles of hibernation.
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Affiliation(s)
- L Elaine Epperson
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, P.O. Box 6511, mail stop 8108, Aurora, CO 80045, USA.
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