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Yang Y, Hao Z, An N, Han Y, Miao W, Storey KB, Lefai E, Liu X, Wang J, Liu S, Xie M, Chang H. Integrated transcriptomics and metabolomics reveal protective effects on heart of hibernating Daurian ground squirrels. J Cell Physiol 2023; 238:2724-2748. [PMID: 37733616 DOI: 10.1002/jcp.31123] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 09/02/2023] [Accepted: 09/08/2023] [Indexed: 09/23/2023]
Abstract
Hibernating mammals are natural models of resistance to ischemia, hypoxia-reperfusion injury, and hypothermia. Daurian ground squirrels (spermophilus dauricus) can adapt to endure multiple torpor-arousal cycles without sustaining cardiac damage. However, the molecular regulatory mechanisms that underlie this adaptive response are not yet fully understood. This study investigates morphological, functional, genetic, and metabolic changes that occur in the heart of ground squirrels in three groups: summer active (SA), late torpor (LT), and interbout arousal (IBA). Morphological and functional changes in the heart were measured using hematoxylin-eosin (HE) staining, Masson staining, echocardiography, and enzyme-linked immunosorbent assay (ELISA). Results showed significant changes in cardiac function in the LT group as compared with SA or IBA groups, but no irreversible damage occurred. To understand the molecular mechanisms underlying these phenotypic changes, transcriptomic and metabolomic analyses were conducted to assess differential changes in gene expression and metabolite levels in the three groups of ground squirrels, with a focus on GO and KEGG pathway analysis. Transcriptomic analysis showed that differentially expressed genes were involved in the remodeling of cytoskeletal proteins, reduction in protein synthesis, and downregulation of the ubiquitin-proteasome pathway during hibernation (including LT and IBA groups), as compared with the SA group. Metabolomic analysis revealed increased free amino acids, activation of the glutathione antioxidant system, altered cardiac fatty acid metabolic preferences, and enhanced pentose phosphate pathway activity during hibernation as compared with the SA group. Combining the transcriptomic and metabolomic data, active mitochondrial oxidative phosphorylation and creatine-phosphocreatine energy shuttle systems were observed, as well as inhibition of ferroptosis signaling pathways during hibernation as compared with the SA group. In conclusion, these results provide new insights into cardio-protection in hibernators from the perspective of gene and metabolite changes and deepen our understanding of adaptive cardio-protection mechanisms in mammalian hibernators.
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Affiliation(s)
- Yingyu Yang
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an, China
| | - Ziwei Hao
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an, China
| | - Ning An
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an, China
| | - Yuting Han
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an, China
| | - Weilan Miao
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an, China
| | - Kenneth B Storey
- Department of Biology, Carleton University, Ottawa, Ontario, Canada
| | - Etienne Lefai
- INRAE, Unité de Nutrition Humaine, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Xiaoxuan Liu
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an, China
| | - Junshu Wang
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an, China
| | - Shuo Liu
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an, China
| | - Manjiang Xie
- Department of Aerospace Physiology, Air Force Medical University, Xi'an, Shaanxi, China
| | - Hui Chang
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an, China
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2
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Ilyina TN, Baishnikova IV. Retinol and α-Tocopherol Content in the Liver and Skeletal Muscle of Bats (Chiroptera) during Hibernation and Summer Activity. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s0022093022060035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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3
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Huang Y, Chu X, Zhang Y, Yang S, Shi Y, Chen Q. Transformation of Mitochondrial Architecture and Dynamics in the Chinese Soft-Shelled Turtle ( Pelodiscus sinensis) During Hibernation. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2022; 28:1-11. [PMID: 35317875 DOI: 10.1017/s1431927622000484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Hibernation is a biological status during which hibernating animals acclimatize themselves to reduced energy consumption through extreme but governed decline in self-metabolism. The role of mitochondria (Mt) in metabolic suppression during hibernation has already been elaborated in different organs and species. Nonetheless, the concretely changing process of mitochondrial architecture and the mechanism underlying this transformation during hibernation remains unclear. Herein, the present study was aimed at clarifying the detailed alteration of mitochondrial morphology and its potential role in the Chinese soft-shelled turtle (Pelodiscus sinensis) during different stages of hibernation. Compared with the nonhibernation period, the mitochondrial architecture was changing from round to crescent, and lipid droplet (LD)/Mt interaction was enhanced during hibernation, as observed by transmission electron microscopy (TEM). Further ultrastructural analysis uncovered that mitochondrial fusion was promptly accelerated in the early stage of hibernation, followed by mitochondrial fission in the middle stage, and mitophagy was boosted in the late stage. Moreover, gene and protein expression related to mitochondrial fusion, fission, and mitophagy accorded closely with the mitochondrial ultrastructural changes in different stages of hibernation. Taken together, our results clarified that the transformation of mitochondrial architecture and mitochondrial dynamics are of vital importance in maintaining internal environment homeostasis of Pelodiscus sinensis.
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Affiliation(s)
- Yufei Huang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province210095, P.R. China
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu Province225009, P.R. China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu Province 225009, P.R. China
| | - Xiaoya Chu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province210095, P.R. China
| | - Yafei Zhang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province210095, P.R. China
| | - Sheng Yang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province210095, P.R. China
| | - Yonghong Shi
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province210095, P.R. China
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai200241, P.R. China
| | - Qiusheng Chen
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province210095, P.R. China
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4
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Shi Z, Qin M, Huang L, Xu T, Chen Y, Hu Q, Peng S, Peng Z, Qu LN, Chen SG, Tuo QH, Liao DF, Wang XP, Wu RR, Yuan TF, Li YH, Liu XM. Human torpor: translating insights from nature into manned deep space expedition. Biol Rev Camb Philos Soc 2020; 96:642-672. [PMID: 33314677 DOI: 10.1111/brv.12671] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/09/2020] [Accepted: 11/17/2020] [Indexed: 12/12/2022]
Abstract
During a long-duration manned spaceflight mission, such as flying to Mars and beyond, all crew members will spend a long period in an independent spacecraft with closed-loop bioregenerative life-support systems. Saving resources and reducing medical risks, particularly in mental heath, are key technology gaps hampering human expedition into deep space. In the 1960s, several scientists proposed that an induced state of suppressed metabolism in humans, which mimics 'hibernation', could be an ideal solution to cope with many issues during spaceflight. In recent years, with the introduction of specific methods, it is becoming more feasible to induce an artificial hibernation-like state (synthetic torpor) in non-hibernating species. Natural torpor is a fascinating, yet enigmatic, physiological process in which metabolic rate (MR), body core temperature (Tb ) and behavioural activity are reduced to save energy during harsh seasonal conditions. It employs a complex central neural network to orchestrate a homeostatic state of hypometabolism, hypothermia and hypoactivity in response to environmental challenges. The anatomical and functional connections within the central nervous system (CNS) lie at the heart of controlling synthetic torpor. Although progress has been made, the precise mechanisms underlying the active regulation of the torpor-arousal transition, and their profound influence on neural function and behaviour, which are critical concerns for safe and reversible human torpor, remain poorly understood. In this review, we place particular emphasis on elaborating the central nervous mechanism orchestrating the torpor-arousal transition in both non-flying hibernating mammals and non-hibernating species, and aim to provide translational insights into long-duration manned spaceflight. In addition, identifying difficulties and challenges ahead will underscore important concerns in engineering synthetic torpor in humans. We believe that synthetic torpor may not be the only option for manned long-duration spaceflight, but it is the most achievable solution in the foreseeable future. Translating the available knowledge from natural torpor research will not only benefit manned spaceflight, but also many clinical settings attempting to manipulate energy metabolism and neurobehavioural functions.
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Affiliation(s)
- Zhe Shi
- National Clinical Research Center for Mental Disorders, and Department of Psychaitry, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China.,Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China.,State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China.,Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, Shanghai, 200030, China
| | - Meng Qin
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Lu Huang
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou, 510632, China
| | - Tao Xu
- Department of Anesthesiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Ying Chen
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Qin Hu
- College of Life Sciences and Bio-Engineering, Beijing University of Technology, Beijing, 100024, China
| | - Sha Peng
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Zhuang Peng
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Li-Na Qu
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
| | - Shan-Guang Chen
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
| | - Qin-Hui Tuo
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Duan-Fang Liao
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Xiao-Ping Wang
- National Clinical Research Center for Mental Disorders, and Department of Psychaitry, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China
| | - Ren-Rong Wu
- National Clinical Research Center for Mental Disorders, and Department of Psychaitry, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China
| | - Ti-Fei Yuan
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, Shanghai, 200030, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226000, China
| | - Ying-Hui Li
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
| | - Xin-Min Liu
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China.,State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China.,Research Center for Pharmacology and Toxicology, Institute of Medicinal Plant Development (IMPLAD), Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100193, China
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5
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Dhillon RS, Denu JM. Using comparative biology to understand how aging affects mitochondrial metabolism. Mol Cell Endocrinol 2017; 455:54-61. [PMID: 28025033 DOI: 10.1016/j.mce.2016.12.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 08/24/2016] [Accepted: 12/16/2016] [Indexed: 02/06/2023]
Abstract
Lifespan varies considerably among even closely related species, as exemplified by rodents and primates. Despite these disparities in lifespan, most studies have focused on intra-specific aging pathologies, primarily within a select few systems. While mice have provided much insight into aging biology, it is unclear if such a short-lived species lack defences against senescence that may have evolved in related longevous species. Many age-related diseases have been linked to mitochondrial dysfunction that are measured by decreased energy generation, structural damage to cellular components, and even cell death. Post translational modifications (PTMs) orchestrate many of the pathways associated with cellular metabolism, and are thought to be a key regulator in biological senescence. We propose hyperacylation as one such modification that may be implicated in numerous mitochondrial impairments affecting energy metabolism.
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Affiliation(s)
- Rashpal S Dhillon
- Department of Biomolecular Chemistry, University of Wisconsin- Madison, Madison, WI 53715, USA.
| | - John M Denu
- Department of Biomolecular Chemistry, University of Wisconsin- Madison, Madison, WI 53715, USA
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6
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Heim AB, Chung D, Florant GL, Chicco AJ. Tissue-specific seasonal changes in mitochondrial function of a mammalian hibernator. Am J Physiol Regul Integr Comp Physiol 2017; 313:R180-R190. [DOI: 10.1152/ajpregu.00427.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 05/03/2017] [Accepted: 05/25/2017] [Indexed: 01/09/2023]
Abstract
Mammalian hibernators, such as golden-mantled ground squirrels ( Callospermophilus lateralis; GMGS), cease to feed while reducing metabolic rate and body temperature during winter months, surviving exclusively on endogenous fuels stored before hibernation. We hypothesized that mitochondria, the cellular sites of oxidative metabolism, undergo tissue-specific seasonal adjustments in carbohydrate and fatty acid utilization to facilitate or complement this remarkable phenotype. To address this, we performed high-resolution respirometry of mitochondria isolated from GMGS liver, heart, skeletal muscle, and brown adipose tissue (BAT) sampled during summer (active), fall (prehibernation), and winter (hibernation) seasons using multisubstrate titration protocols. Mitochondrial phospholipid composition was examined as a postulated intrinsic modulator of respiratory function across tissues and seasons. Respirometry revealed seasonal variations in mitochondrial oxidative phosphorylation capacity, substrate utilization, and coupling efficiency that reflected the distinct functions and metabolic demands of the tissues they support. A consistent finding across tissues was a greater influence of fatty acids (palmitoylcarnitine) on respiratory parameters during the prehibernation and hibernation seasons. In particular, fatty acids had a greater suppressive effect on pyruvate-supported oxidative phosphorylation in heart, muscle, and liver mitochondria and enhanced uncoupled respiration in BAT and muscle mitochondria in the colder seasons. Seasonal variations in the mitochondrial membrane composition reflected changes in the supply and utilization of polyunsaturated fatty acids but were generally mild and inconsistent with functional variations. In conclusion, mitochondria respond to seasonal variations in physical activity, temperature, and nutrient availability in a tissue-specific manner that complements circannual shifts in the bioenergetic and thermoregulatory demands of mammalian hibernators.
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Affiliation(s)
- Ashley B. Heim
- Department of Biology, Colorado State University, Fort Collins, Colorado
| | - Dillon Chung
- Department of Zoology, University of British Colombia, Vancouver, British Columbia, Canada; and
| | - Gregory L. Florant
- Department of Biology, Colorado State University, Fort Collins, Colorado
| | - Adam J. Chicco
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
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7
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The human body as an energetic hybrid? New perspectives for chronic disease treatment? Reumatologia 2017; 55:94-99. [PMID: 28539682 PMCID: PMC5442301 DOI: 10.5114/reum.2017.67605] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 04/19/2017] [Indexed: 12/24/2022] Open
Abstract
Inflammatory response is accompanied by changes in cellular energy metabolism. Proinflammatory mediators like plasma C-reactive protein, IL-6, plasminogen activator inhibitor-1, TNF-α or monocyte chemoattractant protein-1 released in the site of inflammation activates immune cells and increase energy consumption. Increased demand for energy creates local hypoxia and lead in consequence to mitochondrial dysfunction. Metabolism of cells is switched to anaerobic glycolysis. Mitochondria continuously generate free radicals that what result in imbalance that causes oxidative stress, which results in oxidative damage. Chronic energy imbalance promotes oxidative stress, aging, and neurodegeneration and is associated with numerous disorders like Alzheimer’s disease, multiple sclerosis, Parkinson’s disease or Huntington’s disease. It is also believed that oxidative stress and the formation of free radicals play an important role in the pathogenesis of rheumatoid diseases including especially rheumatoid arthritis. Pharmacological control of energy metabolism disturbances may be valuable therapeutic strategy of treatment of this disorders. In recent review we sum up knowledge related to energy disturbances and discuss phenomena such as zombies or hibernation which may indicate the potential targets for regulation of energy metabolism.
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8
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Ballinger MA, Schwartz C, Andrews MT. Enhanced oxidative capacity of ground squirrel brain mitochondria during hibernation. Am J Physiol Regul Integr Comp Physiol 2017; 312:R301-R310. [PMID: 28077389 DOI: 10.1152/ajpregu.00314.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 01/06/2017] [Accepted: 01/08/2017] [Indexed: 11/22/2022]
Abstract
During hibernation, thirteen-lined ground squirrels (Ictidomys tridecemlineatus) regularly cycle between bouts of torpor and interbout arousal (IBA). Most of the brain is electrically quiescent during torpor but regains activity quickly upon arousal to IBA, resulting in extreme oscillations in energy demand during hibernation. We predicted increased functional capacity of brain mitochondria during hibernation compared with spring to accommodate the variable energy demands of hibernation. To address this hypothesis, we examined mitochondrial bioenergetics in the ground squirrel brain across three time points: spring (SP), torpor (TOR), and IBA. Respiration rates of isolated brain mitochondria through complex I of the electron transport chain were more than twofold higher in TOR and IBA than in SP (P < 0.05). We also found a 10% increase in membrane potential between hibernation and spring (P < 0.05), and that proton leak was lower in TOR and IBA than in SP. Finally, there was a 30% increase in calcium loading in SP brain mitochondria compared with TOR and IBA (P < 0.01). To analyze brain mitochondrial abundance between spring and hibernation, we measured the ratio of copy number in a mitochondrial gene (ND1) vs. a nuclear gene (B2M) in frozen cerebral cortex samples. No significant differences were observed in DNA copies between SP and IBA. These data show that brain mitochondrial bioenergetics are not static across the year and suggest that brain mitochondria function more effectively during the hibernation season, allowing for rapid production of energy to meet demand when extreme physiological changes are occurring.
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Affiliation(s)
- Mallory A Ballinger
- Department of Biology, University of Minnesota Duluth, Duluth, Minnesota; and
| | - Christine Schwartz
- Department of Biology, University of Minnesota Duluth, Duluth, Minnesota; and.,Department of Biology, University of Wisconsin-La Crosse, La Crosse, Wisconsin
| | - Matthew T Andrews
- Department of Biology, University of Minnesota Duluth, Duluth, Minnesota; and
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9
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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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10
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Mathers KE, Staples JF. Saponin-permeabilization is not a viable alternative to isolated mitochondria for assessing oxidative metabolism in hibernation. Biol Open 2015; 4:858-64. [PMID: 25979709 PMCID: PMC4571088 DOI: 10.1242/bio.011544] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Saponin permeabilization of tissue slices is increasingly popular for characterizing mitochondrial function largely because it is fast, easy, requires little tissue and leaves much of the cell intact. This technique is well described for mammalian muscle and brain, but not for liver. We sought to evaluate how saponin permeabilization reflects aspects of liver energy metabolism typically assessed in isolated mitochondria. We studied the ground squirrel (Ictidomys tridecemlineatus Mitchell), a hibernating mammal that shows profound and acute whole-animal metabolic suppression in the transition from winter euthermia to torpor. This reversible metabolic suppression is also reflected in the metabolism of isolated liver mitochondria. In this study we compared euthermic and torpid animals using saponin permeabilized tissue and mitochondria isolated from the same livers. As previously demonstrated, isolated mitochondria have state 3 respiration rates, fueled by succinate, that are suppressed by 60-70% during torpor. This result holds whether respiration is standardized to mitochondrial protein, cytochrome a content or citrate synthase activity. In contrast, saponin-permeabilized liver tissue, show no such suppression in torpor. Neither citrate synthase activity nor VDAC content differ between torpor and euthermia, indicating that mitochondrial content remains constant in both permeabilized tissue and isolated mitochondria. In contrast succinate dehydrogenase activity is suppressed during torpor in isolated mitochondria, but not in permeabilized tissue. Mechanisms underlying metabolic suppression in torpor may have been reversed by the permeabilization process. As a result we cannot recommend saponin permeabilization for assessing liver mitochondrial function under conditions where acute changes in metabolism are known to occur.
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Affiliation(s)
- Katherine E Mathers
- Department of Biology, University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - James F Staples
- Department of Biology, University of Western Ontario, London, Ontario N6A 5B7, Canada
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11
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Staples JF. Metabolic suppression in mammalian hibernation: the role of mitochondria. ACTA ACUST UNITED AC 2015; 217:2032-6. [PMID: 24920833 DOI: 10.1242/jeb.092973] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Hibernation evolved in some small mammals that live in cold environments, presumably to conserve energy when food supplies are low. Throughout the winter, hibernators cycle spontaneously between torpor, with low metabolism and near-freezing body temperatures, and euthermia, with high metabolism and body temperatures near 37°C. Understanding the mechanisms underlying this natural model of extreme metabolic plasticity is important for fundamental and applied science. During entrance into torpor, reductions in metabolic rate begin before body temperatures fall, even when thermogenesis is not active, suggesting active mechanisms of metabolic suppression, rather than passive thermal effects. Mitochondrial respiration is suppressed during torpor, especially when measured in liver mitochondria fuelled with succinate at 37°C in vitro. This suppression of mitochondrial metabolism appears to be invoked quickly during entrance into torpor when body temperature is high, but is reversed slowly during arousal when body temperature is low. This pattern may reflect body temperature-sensitive, enzyme-mediated post-translational modifications of oxidative phosphorylation complexes, for instance by phosphorylation or acetylation.
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Affiliation(s)
- James F Staples
- Department of Biology, University of Western Ontario, London, ON, Canada, N6A 5B8
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12
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Revsbech IG, Shen X, Chakravarti R, Jensen FB, Thiel B, Evans AL, Kindberg J, Fröbert O, Stuehr DJ, Kevil CG, Fago A. Hydrogen sulfide and nitric oxide metabolites in the blood of free-ranging brown bears and their potential roles in hibernation. Free Radic Biol Med 2014; 73:349-57. [PMID: 24909614 PMCID: PMC4413933 DOI: 10.1016/j.freeradbiomed.2014.05.025] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 05/19/2014] [Accepted: 05/30/2014] [Indexed: 02/08/2023]
Abstract
During winter hibernation, brown bears (Ursus arctos) lie in dens for half a year without eating while their basal metabolism is largely suppressed. To understand the underlying mechanisms of metabolic depression in hibernation, we measured type and content of blood metabolites of two ubiquitous inhibitors of mitochondrial respiration, hydrogen sulfide (H2S) and nitric oxide (NO), in winter-hibernating and summer-active free-ranging Scandinavian brown bears. We found that levels of sulfide metabolites were overall similar in summer-active and hibernating bears but their composition in the plasma differed significantly, with a decrease in bound sulfane sulfur in hibernation. High levels of unbound free sulfide correlated with high levels of cysteine (Cys) and with low levels of bound sulfane sulfur, indicating that during hibernation H2S, in addition to being formed enzymatically from the substrate Cys, may also be regenerated from its oxidation products, including thiosulfate and polysulfides. In the absence of any dietary intake, this shift in the mode of H2S synthesis would help preserve free Cys for synthesis of glutathione (GSH), a major antioxidant found at high levels in the red blood cells of hibernating bears. In contrast, circulating nitrite and erythrocytic S-nitrosation of glyceraldehyde-3-phosphate dehydrogenase, taken as markers of NO metabolism, did not change appreciably. Our findings reveal that remodeling of H2S metabolism and enhanced intracellular GSH levels are hallmarks of the aerobic metabolic suppression of hibernating bears.
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Affiliation(s)
- Inge G Revsbech
- Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark
| | - Xinggui Shen
- Department of Pathology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
| | - Ritu Chakravarti
- Department of Pathobiology, Cleveland Clinic Lerner Research Institute, Cleveland, OH 44195, USA
| | - Frank B Jensen
- Department of Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Bonnie Thiel
- Department of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Alina L Evans
- Department of Forestry and Wildlife Management, Faculty of Applied Ecology and Agricultural Sciences, Hedmark University College, Campus Evenstad, 2418 Elverum, Norway
| | - Jonas Kindberg
- Department of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences, 90183 Umeå, Sweden
| | - Ole Fröbert
- Department of Cardiology, Örebro University Hospital, 70362 Örebro, Sweden
| | - Dennis J Stuehr
- Department of Pathobiology, Cleveland Clinic Lerner Research Institute, Cleveland, OH 44195, USA
| | - Christopher G Kevil
- Department of Pathology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
| | - Angela Fago
- Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark.
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Quinones QJ, Ma Q, Zhang Z, Barnes BM, Podgoreanu MV. Organ protective mechanisms common to extremes of physiology: a window through hibernation biology. Integr Comp Biol 2014; 54:497-515. [PMID: 24848803 DOI: 10.1093/icb/icu047] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Supply and demand relationships govern survival of animals in the wild and are also key determinants of clinical outcomes in critically ill patients. Most animals' survival strategies focus on the supply side of the equation by pursuing territory and resources, but hibernators are able to anticipate declining availability of nutrients by reducing their energetic needs through the seasonal use of torpor, a reversible state of suppressed metabolic demand and decreased body temperature. Similarly, in clinical medicine the majority of therapeutic interventions to care for critically ill or trauma patients remain focused on elevating physiologic supply above critical thresholds by increasing the main determinants of delivery of oxygen to the tissues (cardiac output, perfusion pressure, hemoglobin concentrations, and oxygen saturation), as well as increasing nutritional support, maintaining euthermia, and other general supportive measures. Techniques, such as induced hypothermia and preconditioning, aimed at diminishing a patient's physiologic requirements as a short-term strategy to match reduced supply and to stabilize their condition, are few and underutilized in clinical settings. Consequently, comparative approaches to understand the mechanistic adaptations that suppress metabolic demand and alter metabolic use of fuel as well as the application of concepts gleaned from studies of hibernation, to the care of critically ill and injured patients could create novel opportunities to improve outcomes in intensive care and perioperative medicine.
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Affiliation(s)
- Quintin J Quinones
- *Department of Anesthesiology, Systems Modeling of Perioperative Organ Injury Laboratory, Duke University, Box 3094, Durham, NC 27710, USA; Institute for Arctic Biology, University of Alaska, Fairbanks, AK, USA
| | - Qing Ma
- *Department of Anesthesiology, Systems Modeling of Perioperative Organ Injury Laboratory, Duke University, Box 3094, Durham, NC 27710, USA; Institute for Arctic Biology, University of Alaska, Fairbanks, AK, USA
| | - Zhiquan Zhang
- *Department of Anesthesiology, Systems Modeling of Perioperative Organ Injury Laboratory, Duke University, Box 3094, Durham, NC 27710, USA; Institute for Arctic Biology, University of Alaska, Fairbanks, AK, USA
| | - Brian M Barnes
- *Department of Anesthesiology, Systems Modeling of Perioperative Organ Injury Laboratory, Duke University, Box 3094, Durham, NC 27710, USA; Institute for Arctic Biology, University of Alaska, Fairbanks, AK, USA
| | - Mihai V Podgoreanu
- *Department of Anesthesiology, Systems Modeling of Perioperative Organ Injury Laboratory, Duke University, Box 3094, Durham, NC 27710, USA; Institute for Arctic Biology, University of Alaska, Fairbanks, AK, USA*Department of Anesthesiology, Systems Modeling of Perioperative Organ Injury Laboratory, Duke University, Box 3094, Durham, NC 27710, USA; Institute for Arctic Biology, University of Alaska, Fairbanks, AK, USA
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Substrate-specific changes in mitochondrial respiration in skeletal and cardiac muscle of hibernating thirteen-lined ground squirrels. J Comp Physiol B 2014; 184:401-14. [PMID: 24408585 DOI: 10.1007/s00360-013-0799-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 12/20/2013] [Accepted: 12/29/2013] [Indexed: 10/25/2022]
Abstract
During torpor, the metabolic rate (MR) of thirteen-lined ground squirrels (Ictidomys tridecemlineatus) is considerably lower relative to euthermia, resulting in part from temperature-independent mitochondrial metabolic suppression in liver and skeletal muscle, which together account for ~40% of basal MR. Although heart accounts for very little (<0.5%) of basal MR, in the present study, we showed that respiration rates were decreased up to 60% during torpor in both subsarcolemmal (SS) and intermyofibrillar (IM) mitochondria from cardiac muscle. We further demonstrated pronounced seasonal (summer vs. winter [i.e., interbout] euthermia) changes in respiration rates in both mitochondrial subpopulations in this tissue, consistent with a shift in fuel use away from carbohydrates and proteins and towards fatty acids and ketones. By contrast, these seasonal changes in respiration rates were not observed in either SS or IM mitochondria isolated from hind limb skeletal muscle. Both populations of skeletal muscle mitochondria, however, did exhibit metabolic suppression during torpor, and this suppression was 2- to 3-fold greater in IM mitochondria, which provide ATP for Ca(2+)- and myosin ATPases, the activities of which are likely quite low in skeletal muscle during torpor because animals are immobile. Finally, these changes in mitochondrial respiration rates were still evident when standardized to citrate synthase activity rather than to total mitochondrial protein.
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Reilly BD, Hickey AJ, Cramp RL, Franklin CE. Decreased hydrogen peroxide production and mitochondrial respiration in skeletal muscle but not cardiac muscle of the green-striped burrowing frog, a natural model of muscle disuse. J Exp Biol 2013; 217:1087-93. [DOI: 10.1242/jeb.096834] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Summary
Suppression of disuse-induced muscle atrophy has been associated with altered mitochondrial reactive oxygen species (ROS) production in mammals. However, despite extended hindlimb immobility aestivating animals exhibit little skeletal muscle atrophy compared with artificially-immobilised mammalian models. Therefore, we studied mitochondrial respiration and ROS (H2O2) production in permeabilised muscle fibres of the green-striped burrowing frog, Cyclorana alboguttata. Mitochondrial respiration within saponin-permeabilised skeletal and cardiac muscle fibres was measured concurrently with ROS production using high-resolution respirometry coupled to custom-made fluorometers. After four months of aestivation, C. alboguttata had significantly depressed whole body metabolism by approximately 70% relative to control (active) frogs, and mitochondrial respiration in saponin-permeabilised skeletal muscle fibres decreased by almost 50% both in the absence of ADP and during oxidative phosphorylation. Mitochondrial ROS production showed up to an 88% depression in aestivating skeletal muscle when malate, succinate and pyruvate were present at concentrations likely reflecting those in vivo. The percentage ROS released per O2 molecule consumed was also approximately 94 % less at these concentrations indicating an intrinsic difference in ROS production capacities during aestivation. We also examined mitochondrial respiration and ROS production in permeabilised cardiac muscle fibres and found that aestivating frogs maintained respiratory flux and ROS production at control levels. These results show that aestivating C. alboguttata has the capacity to independently regulate mitochondrial function in skeletal and cardiac muscles. Furthermore, this work indicates that ROS production can be suppressed in the disused skeletal muscle of aestivating frogs, which may in turn protect against potential oxidative damage and preserve skeletal muscle structure during aestivation and following arousal.
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