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Scott GR, Garvey KM, Wearing OH. The role of the heart in the evolution of aerobic performance. J Exp Biol 2024; 227:jeb247642. [PMID: 39045710 DOI: 10.1242/jeb.247642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2024]
Abstract
Aerobic metabolism underlies vital traits such as locomotion and thermogenesis, and aerobic capacity influences fitness in many animals. The heart is a key determinant of aerobic capacity, but the relative influence of cardiac output versus other steps in the O2 transport pathway remains contentious. In this Commentary, we consider this issue by examining the mechanistic basis for adaptive increases in aerobic capacity (thermogenic V̇O2,max; also called summit metabolism) in deer mice (Peromyscus maniculatus) native to high altitude. Thermogenic V̇O2,max is increased by acclimation to cold hypoxia (simulating high-altitude conditions), and high-altitude populations generally have greater V̇O2,max than their low-altitude counterparts. This plastic and evolved variation in V̇O2,max is associated with corresponding variation in maximal cardiac output, along with variation in other traits across the O2 pathway (e.g. arterial O2 saturation, blood haemoglobin content and O2 affinity, tissue O2 extraction, tissue oxidative capacity). By applying fundamental principles of gas exchange, we show that the relative influence of cardiac output on V̇O2,max depends on the O2 diffusing capacity of thermogenic tissues (skeletal muscles and brown adipose tissues). Functional interactions between cardiac output and blood haemoglobin content determine circulatory O2 delivery and thus affect V̇O2,max, particularly in high-altitude environments where erythropoiesis can increase haematocrit and blood viscosity. There may also be functional linkages between cardiac output and tissue O2 diffusion due to the role of blood flow in determining capillary haematocrit and red blood cell flux. Therefore, the functional interactions between cardiac output and other traits in the O2 pathway underlie the adaptive evolution of aerobic capacities.
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Affiliation(s)
- Graham R Scott
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON, Canada, L8S 4K1
| | - Kayla M Garvey
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON, Canada, L8S 4K1
| | - Oliver H Wearing
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada, V6T 2A1
- Centre for Heart, Lung and Vascular Health, University of British Columbia Okanagan, Kelowna, BC, Canada, V1V 1V7
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2
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Taghizadeh-Hesary F. Is Chronic Ice Water Ingestion a Risk Factor for Gastric Cancer Development? An Evidence-Based Hypothesis Focusing on East Asian Populations. Oncol Ther 2024:10.1007/s40487-024-00299-y. [PMID: 39231856 DOI: 10.1007/s40487-024-00299-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 08/07/2024] [Indexed: 09/06/2024] Open
Abstract
This article introduces a novel risk factor for gastric cancer (GC) by analyzing available epidemiological data from East Asian populations. A significantly higher age-standardized GC rate was observed in Japanese and Korean populations than in Chinese populations, despite nearly identical ethnicity, food habits, obesity rates, and alcohol consumption. Given the pivotal role of environmental factors in GC development, particularly for the intestinal type, a thorough evaluation of the lifestyles of these three populations was conducted to identify commonalities and disparities. It was observed that Japanese and Korean individuals prefer consuming ice water, while Chinese individuals tend to drink warm water, potentially influenced by traditional Chinese medicine disciplines. Considering the key features of GC development, a literature review was conducted to investigate the mechanisms through which the consumption of ice water might contribute to GC initiation and progression. Mechanistically, exposing gastric cells to hypothermia can increase the risk of carcinogenesis through multiple pathways. This includes the promotion of Helicobacter pylori colonization, prolonged gastric inflammation, and mitochondrial dysfunction in gastric cells. Furthermore, drinking ice water can enhance the survival, proliferation, and invasion of GC cells by releasing cold shock proteins, increasing gastric acid secretion, and delaying gastric emptying. Additionally, hypothermia can boost the immune evasion of cancer cells by weakening the antitumor immune system and activating different components of the tumor microenvironment. This paper also explores the association between exposure of GC cells to hypothermia and current insights into cancer hallmarks. These findings may partially elucidate the higher incidence of GC in Japanese and Korean populations and provide a clue for future experimental studies.Graphical abstract available for this article.
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Affiliation(s)
- Farzad Taghizadeh-Hesary
- ENT and Head and Neck Research Center and Department, The Five Senses Health Institute, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
- Radiation Oncology Department, Iran University of Medical Sciences, Tehran, Iran.
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3
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Bautista NM, Herrera ND, Shadowitz E, Wearing OH, Cheviron ZA, Scott GR, Storz JF. Local adaptation, plasticity, and evolved resistance to hypoxic cold stress in high-altitude deer mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.21.600120. [PMID: 38979138 PMCID: PMC11230211 DOI: 10.1101/2024.06.21.600120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
A fundamental question in evolutionary biology concerns the relative contributions of phenotypic plasticity vs. local adaptation (genotypic specialization) in enabling wide-ranging species to inhabit diverse environmental conditions. Here we conduct a long-term hypoxia acclimation experiment to assess the relative roles of local adaptation and plasticity in enabling highland and lowland deer mice (Peromyscus maniculatus) to sustain aerobic thermogenesis at progressively increasing elevations. We assessed the relative physiological performance capacities of highland and lowland natives as they were exposed to progressive, stepwise increases in hypoxia, simulating the gradual ascent from sea level to an elevation of 6000 m. The final elevation of 6000 m far exceeds the highest attainable elevations within the species' range, and therefore tests the animals' ability to tolerate levels of hypoxia that surpass the prevailing conditions within their current distributional limits. Our results demonstrate that highland natives exhibit superior thermogenic capacities at the most severe levels of hypoxia, suggesting that the species' broad fundamental niche and its ability to inhabit such a broad range of elevational zones is attributable to a combination of genetically based local adaptation and plasticity. Transcriptomic and physiological measurements identify evolved changes in the acclimation response to hypoxia that contribute to the enhanced thermogenic capacity of highland natives.
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Affiliation(s)
- Naim M Bautista
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588, USA
| | | | - Ellen Shadowitz
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Oliver H Wearing
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Zachary A Cheviron
- Division of Biological Sciences, University of Montana, Missoula, MT 59812
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588, USA
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4
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Garrett EJ, Prasad SK, Schweizer RM, McClelland GB, Scott GR. Evolved changes in phenotype across skeletal muscles in deer mice native to high altitude. Am J Physiol Regul Integr Comp Physiol 2024; 326:R297-R310. [PMID: 38372126 PMCID: PMC11283899 DOI: 10.1152/ajpregu.00206.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 01/11/2024] [Accepted: 02/09/2024] [Indexed: 02/20/2024]
Abstract
The cold and hypoxic conditions at high altitude necessitate high metabolic O2 demands to support thermogenesis while hypoxia reduces O2 availability. Skeletal muscles play key roles in thermogenesis, but our appreciation of muscle plasticity and adaptation at high altitude has been hindered by past emphasis on only a small number of muscles. We examined this issue in deer mice (Peromyscus maniculatus). Mice derived from both high-altitude and low-altitude populations were born and raised in captivity and then acclimated as adults to normoxia or hypobaric hypoxia (12 kPa O2 for 6-8 wk). Maximal activities of citrate synthase (CS), cytochrome c oxidase (COX), β-hydroxyacyl-CoA dehydrogenase (HOAD), hexokinase (HK), pyruvate kinase (PK), and lactate dehydrogenase (LDH) were measured in 20 muscles involved in shivering, locomotion, body posture, ventilation, and mastication. Principal components analysis revealed an overall difference in muscle phenotype between populations but no effect of hypoxia acclimation. High-altitude mice had greater activities of mitochondrial enzymes and/or lower activities of PK or LDH across many (but not all) respiratory, limb, core and mastication muscles compared with low-altitude mice. In contrast, chronic hypoxia had very few effects across muscles. Further examination of CS in the gastrocnemius showed that population differences in enzyme activity stemmed from differences in protein abundance and mRNA expression but not from population differences in CS amino acid sequence. Overall, our results suggest that evolved increases in oxidative capacity across many skeletal muscles, at least partially driven by differences in transcriptional regulation, may contribute to high-altitude adaptation in deer mice.NEW & NOTEWORTHY Most previous studies of muscle plasticity and adaptation in high-altitude environments have focused on a very limited number of skeletal muscles. Comparing high-altitude versus low-altitude populations of deer mice, we show that a large number of muscles involved in shivering, locomotion, body posture, ventilation, and mastication exhibit greater mitochondrial enzyme activities in the high-altitude population. Therefore, evolved increases in mitochondrial oxidative capacity across skeletal muscles contribute to high-altitude adaptation.
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Affiliation(s)
- Emily J Garrett
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Srikripa K Prasad
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Rena M Schweizer
- Division of Biological Sciences, University of Montana, Missoula, Montana, United States
- United States Department of Agriculture, Agricultural Research Service, Pollinating Insects Research Unit, Utah State University, Logan, Utah, United States
| | | | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
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5
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Lyons SA, McClelland GB. Highland deer mice support increased thermogenesis in response to chronic cold hypoxia by shifting uptake of circulating fatty acids from muscles to brown adipose tissue. J Exp Biol 2024; 227:jeb247340. [PMID: 38506250 PMCID: PMC11057874 DOI: 10.1242/jeb.247340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 03/14/2024] [Indexed: 03/21/2024]
Abstract
During maximal cold challenge (cold-induced V̇O2,max) in hypoxia, highland deer mice (Peromyscus maniculatus) show higher rates of circulatory fatty acid delivery compared with lowland deer mice. Fatty acid delivery also increases with acclimation to cold hypoxia (CH) and probably plays a major role in supporting the high rates of thermogenesis observed in highland deer mice. However, it is unknown which tissues take up these fatty acids and their relative contribution to thermogenesis. The goal of this study was to determine the uptake of circulating fatty acids into 24 different tissues during hypoxic cold-induced V̇O2,max, by using [1-14C]2-bromopalmitic acid. To uncover evolved and environment-induced changes in fatty acid uptake, we compared lab-born and -raised highland and lowland deer mice, acclimated to either thermoneutral (30°C, 21 kPa O2) or CH (5°C, 12 kPa O2) conditions. During hypoxic cold-induced V̇O2,max, CH-acclimated highlanders decreased muscle fatty acid uptake and increased uptake into brown adipose tissue (BAT) relative to thermoneutral highlanders, a response that was absent in lowlanders. CH acclimation was also associated with increased activities of enzymes citrate synthase and β-hydroxyacyl-CoA dehydrogenase in the BAT of highlanders, and higher levels of fatty acid translocase CD36 (FAT/CD36) in both populations. This is the first study to show that cold-induced fatty acid uptake is distributed across a wide range of tissues. Highland deer mice show plasticity in this fatty acid distribution in response to chronic cold hypoxia, and combined with higher rates of tissue delivery, this contributes to their survival in the cold high alpine environment.
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Affiliation(s)
- Sulayman A. Lyons
- Department of Biology, McMaster University, Hamilton, ON, Canada, L8S 4K1
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6
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Graham AM, Lavretsky P, Wilson RE, McCracken KG. High-altitude adaptation is accompanied by strong signatures of purifying selection in the mitochondrial genomes of three Andean waterfowl. PLoS One 2024; 19:e0294842. [PMID: 38170710 PMCID: PMC10763953 DOI: 10.1371/journal.pone.0294842] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 11/09/2023] [Indexed: 01/05/2024] Open
Abstract
Evidence from a variety of organisms points to convergent evolution on the mitochondria associated with a physiological response to oxygen deprivation or temperature stress, including mechanisms for high-altitude adaptation. Here, we examine whether demography and/or selection explains standing mitogenome nucleotide diversity in high-altitude adapted populations of three Andean waterfowl species: yellow-billed pintail (Anas georgica), speckled teal (Anas flavirostris), and cinnamon teal (Spatula cyanoptera). We compared a total of 60 mitogenomes from each of these three duck species (n = 20 per species) across low and high altitudes and tested whether part(s) or all of the mitogenome exhibited expected signatures of purifying selection within the high-altitude populations of these species. Historical effective population sizes (Ne) were inferred to be similar between high- and low-altitude populations of each species, suggesting that selection rather than genetic drift best explains the reduced genetic variation found in mitochondrial genes of high-altitude populations compared to low-altitude populations of the same species. Specifically, we provide evidence that establishment of these three Andean waterfowl species in the high-altitude environment, coincided at least in part with a persistent pattern of negative purifying selection acting on oxidative phosphorylation (OXPHOS) function of the mitochondria. Our results further reveal that the extent of gene-specific purifying selection has been greatest in the speckled teal, the species with the longest history of high-altitude occupancy.
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Affiliation(s)
- Allie M. Graham
- Eccles Institute for Human Genetics, University of Utah, Salt Lake City, UT, United States of America
| | - Philip Lavretsky
- Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, United States of America
| | - Robert E. Wilson
- School of Natural Resources and Nebraska State Museum, University of Nebraska–Lincoln, Lincoln, NE, United States of America
| | - Kevin G. McCracken
- Department of Biology, University of Miami, Coral Gables, FL, United States of America
- Department of Marine Biology and Ecology, Rosenstiel School of Marine, Atmospheric, and Earth Science, University of Miami, Miami, FL, United States of America
- Human Genetics and Genomics, University of Miami Miller School of Medicine, Miami, FL, United States of America
- University of Alaska Museum, University of Alaska Fairbanks, Fairbanks, AK, United States of America
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7
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Storz JF, Scott GR. To what extent do physiological tolerances determine elevational range limits of mammals? J Physiol 2023:10.1113/JP284586. [PMID: 37889163 PMCID: PMC11052920 DOI: 10.1113/jp284586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 09/26/2023] [Indexed: 10/28/2023] Open
Abstract
A key question in biology concerns the extent to which distributional range limits of species are determined by intrinsic limits of physiological tolerance. Here, we use common-garden data for wild rodents to assess whether species with higher elevational range limits typically have higher thermogenic capacities in comparison to closely related lowland species. Among South American leaf-eared mice (genus Phyllotis), mean thermogenic performance is higher in species with higher elevational range limits, but there is little among-species variation in the magnitude of plasticity in this trait. In the North American rodent genus Peromyscus, highland deer mice (Peromyscus maniculatus) have greater thermogenic maximal oxygen uptake (V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ ) than lowland white-footed mice (Peromyscus leucopus) at a level of hypoxia that matches the upper elevational range limit of the former species. In highland deer mice, the enhanced thermogenicV ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ in hypoxia is attributable to a combination of evolved and plastic changes in physiological pathways that govern the transport and utilization of O2 and metabolic substrates. Experiments with Peromyscus mice also demonstrate that exposure to hypoxia during different stages of development elicits plastic changes in cardiorespiratory traits that improve thermogenicV ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ via distinct physiological mechanisms. Evolved differences in thermogenic capacity provide clues about why some species are able to persist in higher-elevation habitats that lie slightly beyond the tolerable limits of other species. Such differences in environmental tolerance also suggest why some species might be more vulnerable to climate change than others.
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Affiliation(s)
- Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, ON, Canada
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8
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Zhang D, Wang L, Wang W, Liu D. The Role of lncRNAs in Pig Muscle in Response to Cold Exposure. Genes (Basel) 2023; 14:1901. [PMID: 37895249 PMCID: PMC10606478 DOI: 10.3390/genes14101901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 09/27/2023] [Accepted: 09/28/2023] [Indexed: 10/29/2023] Open
Abstract
Cold exposure is an essential factor affecting breeding efforts in cold regions. Muscle, as an important tissue for homeothermic animals, can produce heat through shivering thermogenesis (ST) and non-shivering thermogenesis (NST) under cold exposure. Long non-coding RNAs (lncRNAs) play important roles in regulating gene expression. However, the regulatory mechanisms of lncRNAs and their role in the thermogenesis of pigs are unclear. We examined lncRNAs in the skeletal muscle of an indigenous pig breed, the Enshi black pig, when the pigs were exposed to acute or chronic cold. Three pigs were maintained inside a pig house (control group), three pigs were maintained outside the pig house for 55 d (chronic cold group), and three pigs were suddenly exposed to the conditions outside the pig house for 3 days (acute cold group). After the experiment, the longissimus dorsi of each pig were collected, and their lncRNA profiles were sequenced and analyzed. Each sample obtained nearly 12.56 Gb of clean data. A total of 11,605 non-coding RNAs were obtained, including 10,802 novel lncRNAs. The number of differentially expressed lncRNAs (DElncRNAs) was identified under acute cold (427) and cold acclimation (376), with 215 and 192 upregulated lncRNAs, respectively. However, only 113 lncRNAs were commonly upregulated by acute cold and cold acclimation. In addition, 65% of the target genes were trans-regulated by DElncRNAs. The target genes were enriched in signal transduction, immune system, cell growth and death pathways, and amino acid and carbohydrate metabolism. Compared to cold acclimation, acute cold stress-induced more DElncRNAs and response pathways. In conclusion, low temperatures altered the expression levels of lncRNAs and their target genes in muscle tissue. Some potential mechanisms were revealed, including ion migration and the metabolism of amino acids and carbohydrates.
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Affiliation(s)
| | | | | | - Di Liu
- Institute of Animal Husbandry, Heilongjiang Academy of Agricultural Sciences, Harbin 150086, China; (D.Z.); (L.W.); (W.W.)
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9
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Chen W, Xu Z, You W, Zhou Y, Wang L, Huang Y, Shan T. Cold exposure alters lipid metabolism of skeletal muscle through HIF-1α-induced mitophagy. BMC Biol 2023; 21:27. [PMID: 36750818 PMCID: PMC9906913 DOI: 10.1186/s12915-023-01514-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 01/12/2023] [Indexed: 02/09/2023] Open
Abstract
BACKGROUND In addition to its contractile properties and role in movement, skeletal muscle plays an important function in regulating whole-body glucose and lipid metabolism. A central component of such regulation is mitochondria, whose quality and function are essential in maintaining proper metabolic homeostasis, with defects in processes such as autophagy and mitophagy involved in mitochondria quality control impairing skeletal muscle mass and function, and potentially leading to a number of associated diseases. Cold exposure has been reported to markedly induce metabolic remodeling and enhance insulin sensitivity in the whole body by regulating mitochondrial biogenesis. However, changes in lipid metabolism and lipidomic profiles in skeletal muscle in response to cold exposure are unclear. Here, we generated lipidomic or transcriptome profiles of mouse skeletal muscle following cold induction, to dissect the molecular mechanisms regulating lipid metabolism upon acute cold treatment. RESULTS Our results indicated that short-term cold exposure (3 days) can lead to a significant increase in intramuscular fat deposition. Lipidomic analyses revealed that a cold challenge altered the overall lipid composition by increasing the content of triglyceride (TG), lysophosphatidylcholine (LPC), and lysophosphatidylethanolamine (LPE), while decreasing sphingomyelin (SM), validating lipid remodeling during the cold environment. In addition, RNA-seq and qPCR analysis showed that cold exposure promoted the expression of genes related to lipolysis and fatty acid biosynthesis. These marked changes in metabolic effects were associated with mitophagy and muscle signaling pathways, which were accompanied by increased TG deposition and impaired fatty acid oxidation. Mechanistically, HIF-1α signaling was highly activated in response to the cold challenge, which may contribute to intramuscular fat deposition and enhanced mitophagy in a cold environment. CONCLUSIONS Overall, our data revealed the adaptive changes of skeletal muscle associated with lipidomic and transcriptomic profiles upon cold exposure. We described the significant alterations in the composition of specific lipid species and expression of genes involved in glucose and fatty acid metabolism. Cold-mediated mitophagy may play a critical role in modulating lipid metabolism in skeletal muscle, which is precisely regulated by HIF-1α signaling.
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Affiliation(s)
- Wentao Chen
- grid.13402.340000 0004 1759 700XCollege of Animal Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058 China ,grid.419897.a0000 0004 0369 313XKey Laboratory of Molecular Animal Nutrition (Zhejiang University), Ministry of Education, 866 Yuhangtang Road, Hangzhou, 310058 China ,Key Laboratory of Animal Feed and Nutrition of Zhejiang Province, 866 Yuhangtang Road, Hangzhou, China
| | - Ziye Xu
- grid.13402.340000 0004 1759 700XCollege of Animal Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058 China ,grid.419897.a0000 0004 0369 313XKey Laboratory of Molecular Animal Nutrition (Zhejiang University), Ministry of Education, 866 Yuhangtang Road, Hangzhou, 310058 China ,Key Laboratory of Animal Feed and Nutrition of Zhejiang Province, 866 Yuhangtang Road, Hangzhou, China
| | - Wenjing You
- grid.13402.340000 0004 1759 700XCollege of Animal Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058 China ,grid.419897.a0000 0004 0369 313XKey Laboratory of Molecular Animal Nutrition (Zhejiang University), Ministry of Education, 866 Yuhangtang Road, Hangzhou, 310058 China ,Key Laboratory of Animal Feed and Nutrition of Zhejiang Province, 866 Yuhangtang Road, Hangzhou, China
| | - Yanbing Zhou
- grid.13402.340000 0004 1759 700XCollege of Animal Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058 China ,grid.419897.a0000 0004 0369 313XKey Laboratory of Molecular Animal Nutrition (Zhejiang University), Ministry of Education, 866 Yuhangtang Road, Hangzhou, 310058 China ,Key Laboratory of Animal Feed and Nutrition of Zhejiang Province, 866 Yuhangtang Road, Hangzhou, China
| | - Liyi Wang
- grid.13402.340000 0004 1759 700XCollege of Animal Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058 China ,grid.419897.a0000 0004 0369 313XKey Laboratory of Molecular Animal Nutrition (Zhejiang University), Ministry of Education, 866 Yuhangtang Road, Hangzhou, 310058 China ,Key Laboratory of Animal Feed and Nutrition of Zhejiang Province, 866 Yuhangtang Road, Hangzhou, China
| | - Yuqin Huang
- grid.13402.340000 0004 1759 700XCollege of Animal Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058 China ,grid.419897.a0000 0004 0369 313XKey Laboratory of Molecular Animal Nutrition (Zhejiang University), Ministry of Education, 866 Yuhangtang Road, Hangzhou, 310058 China ,Key Laboratory of Animal Feed and Nutrition of Zhejiang Province, 866 Yuhangtang Road, Hangzhou, China
| | - Tizhong Shan
- College of Animal Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China. .,Key Laboratory of Molecular Animal Nutrition (Zhejiang University), Ministry of Education, 866 Yuhangtang Road, Hangzhou, 310058, China. .,Key Laboratory of Animal Feed and Nutrition of Zhejiang Province, 866 Yuhangtang Road, Hangzhou, China.
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10
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Structural functionality of skeletal muscle mitochondria and its correlation with metabolic diseases. Clin Sci (Lond) 2022; 136:1851-1871. [PMID: 36545931 DOI: 10.1042/cs20220636] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 12/24/2022]
Abstract
The skeletal muscle is one of the largest organs in the mammalian body. Its remarkable ability to swiftly shift its substrate selection allows other organs like the brain to choose their preferred substrate first. Healthy skeletal muscle has a high level of metabolic flexibility, which is reduced in several metabolic diseases, including obesity and Type 2 diabetes (T2D). Skeletal muscle health is highly dependent on optimally functioning mitochondria that exist in a highly integrated network with the sarcoplasmic reticulum and sarcolemma. The three major mitochondrial processes: biogenesis, dynamics, and mitophagy, taken together, determine the quality of the mitochondrial network in the muscle. Since muscle health is primarily dependent on mitochondrial status, the mitochondrial processes are very tightly regulated in the skeletal muscle via transcription factors like peroxisome proliferator-activated receptor-γ coactivator-1α, peroxisome proliferator-activated receptors, estrogen-related receptors, nuclear respiratory factor, and Transcription factor A, mitochondrial. Physiological stimuli that enhance muscle energy expenditure, like cold and exercise, also promote a healthy mitochondrial phenotype and muscle health. In contrast, conditions like metabolic disorders, muscle dystrophies, and aging impair the mitochondrial phenotype, which is associated with poor muscle health. Further, exercise training is known to improve muscle health in aged individuals or during the early stages of metabolic disorders. This might suggest that conditions enhancing mitochondrial health can promote muscle health. Therefore, in this review, we take a critical overview of current knowledge about skeletal muscle mitochondria and the regulation of their quality. Also, we have discussed the molecular derailments that happen during various pathophysiological conditions and whether it is an effect or a cause.
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11
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Wearing OH, Scott GR. Evolved reductions in body temperature and the metabolic costs of thermoregulation in deer mice native to high altitude. Proc Biol Sci 2022; 289:20221553. [PMID: 36168757 PMCID: PMC9515628 DOI: 10.1098/rspb.2022.1553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 08/30/2022] [Indexed: 11/12/2022] Open
Abstract
The evolution of endothermy was instrumental to the diversification of birds and mammals, but the energetic demands of maintaining high body temperature could offset the advantages of endothermy in some environments. We hypothesized that reductions in body temperature help high-altitude natives overcome the metabolic challenges of cold and hypoxia in their native environment. Deer mice (Peromyscus maniculatus) from high-altitude and low-altitude populations were bred in captivity to the second generation and were acclimated as adults to warm normoxia or cold hypoxia. Subcutaneous temperature (Tsub, used as a proxy for body temperature) and cardiovascular function were then measured throughout the diel cycle using biotelemetry. Cold hypoxia increased metabolic demands, as reflected by increased food consumption and heart rate (associated with reduced vagal tone). These increased metabolic demands were offset by plastic reductions in Tsub (approx. 2°C) in response to cold hypoxia, and highlanders had lower Tsub (approx. 1°C) than lowlanders in both environmental treatments. Empirical and theoretical evidence suggested that these reductions could together reduce metabolic demands by approximately 10-30%. Therefore, plastic and evolved reductions in body temperature can help mammals overcome the metabolic challenges at high altitude and may be a valuable energy-saving strategy in some non-hibernating endotherms in extreme environments.
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Affiliation(s)
- Oliver H. Wearing
- Department of Biology, McMaster University, Life Sciences Building, 1280 Main Street W, Hamilton, ON, Canada L8S 4K1
| | - Graham R. Scott
- Department of Biology, McMaster University, Life Sciences Building, 1280 Main Street W, Hamilton, ON, Canada L8S 4K1
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12
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Chen Y, Tan S, Fu J. Modified Metabolism and Response to UV Radiation: Gene Expression Variations Along an Elevational Gradient in the Asiatic Toad (Bufo gargarizans). J Mol Evol 2022; 90:389-399. [PMID: 36029325 DOI: 10.1007/s00239-022-10070-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 08/09/2022] [Indexed: 12/01/2022]
Abstract
High-elevation adaptation provides an excellent system for examining adaptive evolution, and adaptive variations may manifest at gene expression or any other phenotypic levels. We examined gene expression profiles of Asiatic toads (Bufo gargarizans) along an elevational gradient from both wild and common-garden acclimated populations. Asiatic toads originated from high altitudes have distinctive gene expression patterns. We identified 18 fixed differentially expressed genes (DEGs), which are different in both wild and acclimated samples, and 1217 plastic DEGs, which are different among wild samples. The expression levels of most genes were linearly correlated with altitude gradient and down-regulated in high-altitude populations. Expression variations of several genes associated with metabolic process are fixed, and we also identified a co-expression module that is significantly different between acclimated populations and has functions related to DNA repair. The differential expression of the vast majority genes, however, are due to phenotypic plasticity, revealing the highly plastic nature of gene expression variations. Expression modification of some specific genes related to metabolism and response to UV radiation play crucial role in adaptation to high altitude for Asiatic toads. Common-garden experiments are essential for evaluating adaptive evolution of natural populations.
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Affiliation(s)
- Ying Chen
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China.
- The University of Chinese Academy of Science, Beijing, China.
| | - Song Tan
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
- The University of Chinese Academy of Science, Beijing, China
| | - Jinzhong Fu
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada.
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13
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Yu JJ, Non AL, Heinrich EC, Gu W, Alcock J, Moya EA, Lawrence ES, Tift MS, O'Brien KA, Storz JF, Signore AV, Khudyakov JI, Milsom WK, Wilson SM, Beall CM, Villafuerte FC, Stobdan T, Julian CG, Moore LG, Fuster MM, Stokes JA, Milner R, West JB, Zhang J, Shyy JY, Childebayeva A, Vázquez-Medina JP, Pham LV, Mesarwi OA, Hall JE, Cheviron ZA, Sieker J, Blood AB, Yuan JX, Scott GR, Rana BK, Ponganis PJ, Malhotra A, Powell FL, Simonson TS. Time Domains of Hypoxia Responses and -Omics Insights. Front Physiol 2022; 13:885295. [PMID: 36035495 PMCID: PMC9400701 DOI: 10.3389/fphys.2022.885295] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Accepted: 05/24/2022] [Indexed: 02/04/2023] Open
Abstract
The ability to respond rapidly to changes in oxygen tension is critical for many forms of life. Challenges to oxygen homeostasis, specifically in the contexts of evolutionary biology and biomedicine, provide important insights into mechanisms of hypoxia adaptation and tolerance. Here we synthesize findings across varying time domains of hypoxia in terms of oxygen delivery, ranging from early animal to modern human evolution and examine the potential impacts of environmental and clinical challenges through emerging multi-omics approaches. We discuss how diverse animal species have adapted to hypoxic environments, how humans vary in their responses to hypoxia (i.e., in the context of high-altitude exposure, cardiopulmonary disease, and sleep apnea), and how findings from each of these fields inform the other and lead to promising new directions in basic and clinical hypoxia research.
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Affiliation(s)
- James J. Yu
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Amy L. Non
- Department of Anthropology, Division of Social Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Erica C. Heinrich
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, United States
| | - Wanjun Gu
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
- Herbert Wertheim School of Public Health and Longevity Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Joe Alcock
- Department of Emergency Medicine, University of New Mexico, Albuquerque, MX, United States
| | - Esteban A. Moya
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Elijah S. Lawrence
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Michael S. Tift
- Department of Biology and Marine Biology, College of Arts and Sciences, University of North Carolina Wilmington, Wilmington, NC, United States
| | - Katie A. O'Brien
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
- Department of Physiology, Development and Neuroscience, Faculty of Biology, School of Biological Sciences, University of Cambridge, Cambridge, ENG, United Kingdom
| | - Jay F. Storz
- School of Biological Sciences, College of Arts and Sciences, University of Nebraska-Lincoln, Lincoln, IL, United States
| | - Anthony V. Signore
- School of Biological Sciences, College of Arts and Sciences, University of Nebraska-Lincoln, Lincoln, IL, United States
| | - Jane I. Khudyakov
- Department of Biological Sciences, University of the Pacific, Stockton, CA, United States
| | | | - Sean M. Wilson
- Lawrence D. Longo, MD Center for Perinatal Biology, Loma Linda, CA, United States
| | | | | | | | - Colleen G. Julian
- School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Lorna G. Moore
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, Aurora, CO, United States
| | - Mark M. Fuster
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Jennifer A. Stokes
- Department of Kinesiology, Southwestern University, Georgetown, TX, United States
| | - Richard Milner
- San Diego Biomedical Research Institute, San Diego, CA, United States
| | - John B. West
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Jiao Zhang
- Department of Medicine, UC San Diego School of Medicine, San Diego, CA, United States
| | - John Y. Shyy
- Department of Medicine, UC San Diego School of Medicine, San Diego, CA, United States
| | - Ainash Childebayeva
- Department of Archaeogenetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - José Pablo Vázquez-Medina
- Department of Integrative Biology, College of Letters and Science, University of California, Berkeley, Berkeley, CA, United States
| | - Luu V. Pham
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, School of Medicine, Johns Hopkins Medicine, Baltimore, MD, United States
| | - Omar A. Mesarwi
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - James E. Hall
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Zachary A. Cheviron
- Division of Biological Sciences, College of Humanities and Sciences, University of Montana, Missoula, MT, United States
| | - Jeremy Sieker
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Arlin B. Blood
- Department of Pediatrics Division of Neonatology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Jason X. Yuan
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Graham R. Scott
- Department of Pediatrics Division of Neonatology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Brinda K. Rana
- Moores Cancer Center, UC San Diego, La Jolla, CA, United States
- Department of Psychiatry, UC San Diego, La Jolla, CA, United States
| | - Paul J. Ponganis
- Center for Marine Biotechnology and Biomedicine, La Jolla, CA, United States
| | - Atul Malhotra
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Frank L. Powell
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Tatum S. Simonson
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
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14
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Pani P, Bal NC. Avian adjustments to cold and non-shivering thermogenesis: whats, wheres and hows. Biol Rev Camb Philos Soc 2022; 97:2106-2126. [PMID: 35899483 DOI: 10.1111/brv.12885] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 11/28/2022]
Abstract
Avian cold adaptation is hallmarked by innovative strategies of both heat conservation and thermogenesis. While minimizing heat loss can reduce the thermogenic demands of body temperature maintenance, it cannot eliminate the requirement for thermogenesis. Shivering and non-shivering thermogenesis (NST) are the two synergistic mechanisms contributing to endothermy. Birds are of particular interest in studies of NST as they lack brown adipose tissue (BAT), the major organ of NST in mammals. Critical analysis of the existing literature on avian strategies of cold adaptation suggests that skeletal muscle is the principal site of NST. Despite recent progress, isolating the mechanisms involved in avian muscle NST has been difficult as shivering and NST co-exist with its primary locomotory function. Herein, we re-evaluate various proposed molecular bases of avian skeletal muscle NST. Experimental evidence suggests that sarco(endo)plasmic reticulum Ca2+ -ATPase (SERCA) and ryanodine receptor 1 (RyR1) are key in avian muscle NST, through their mediation of futile Ca2+ cycling and thermogenesis. More recent studies have shown that SERCA regulation by sarcolipin (SLN) facilitates muscle NST in mammals; however, its role in birds is unclear. Ca2+ signalling in the muscle seems to be common to contraction, shivering and NST, but elucidating its roles will require more precise measurement of local Ca2+ levels inside avian myofibres. The endocrine control of avian muscle NST is still poorly defined. A better understanding of the mechanistic details of avian muscle NST will provide insights into the roles of these processes in regulatory thermogenesis, which could further inform our understanding of the evolution of endothermy among vertebrates.
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Affiliation(s)
- Punyadhara Pani
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha, 751024, India
| | - Naresh C Bal
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha, 751024, India
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15
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Ivy CM, Velotta JP, Cheviron ZA, Scott GR. Genetic variation in HIF-2α attenuates ventilatory sensitivity and carotid body growth in chronic hypoxia in high-altitude deer mice. J Physiol 2022; 600:4207-4225. [PMID: 35797482 DOI: 10.1113/jp282798] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 06/27/2022] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS High-altitude natives of many species have experienced natural selection on the gene encoding HIF-2α, Epas1, including high-altitude populations of deer mice. HIF-2α regulates ventilation and carotid body growth in hypoxia, so the genetic variants in Epas1 in high-altitude natives may underlie evolved changes in control of breathing. Deer mice from controlled crosses between high- and low-altitude populations were used to examine the effects of Epas1 genotype on an admixed genomic background. The high-altitude variant was associated with reduced ventilatory chemosensitivity and carotid body growth in chronic hypoxia, but had no effects on haematology. The results help us better understand the genetic basis for the unique physiological phenotype of high-altitude natives. ABSTRACT The gene encoding HIF-2α, Epas1, has experienced a history of natural selection in many high-altitude taxa, but the functional role of mutations in this gene are still poorly understood. We investigated the influence of the high-altitude variant of Epas1 in North American deer mice (Peromyscus maniculatus) on control of breathing and carotid body growth during chronic hypoxia. We created hybrids between high- and low-altitude populations of deer mice to disrupt linkages between genetic loci so physiological effects of Epas1 alleles (Epas1H and Epas1L , respectively) could be examined on an admixed genomic background. In general, chronic hypoxia (4 weeks at 12 kPa O2 ) enhanced ventilatory chemosensitivity (assessed as the acute ventilatory response to hypoxia), increased total ventilation and arterial O2 saturation during progressive poikilocapnic hypoxia, and increased haematocrit and blood haemoglobin content across genotypes. However, effects of chronic hypoxia on ventilatory chemosensitivity were attenuated in mice that were homozygous for the high-altitude Epas1 allele (Epas1H/H ). Carotid body growth and glomus cell hyperplasia, which was strongly induced in Epas1L/L mice in chronic hypoxia, was not observed in Epas1H/H mice. Epas1 genotype also modulated the effects of chronic hypoxia on metabolism and body temperature depression in hypoxia, but had no effects on haematological traits. These findings confirm the important role of HIF-2α in modulating ventilatory sensitivity and carotid body growth in chronic hypoxia, and show that genetic variation in Epas1 is responsible for evolved changes in the control of breathing and metabolism in high-altitude deer mice. Abstract figure legend ventilation and carotid body growth in hypoxia, so we investigated the role genetic variants in Epas1 in highaltitude deer mice on the control of breathing. In the lab, hybrids between high- and lowaltitude populations of deer mice were created to disrupt linkages between genetic loci so physiological effects of Epas1 alleles (Epas1H and Epas1L, respectively) could be examined on an admixed genomic background. The high-altitude variant was associated with reduced ventilatory chemosensitivity and carotid body growth after 4 weeks of chronic hypoxia, compared to mice homozygous for the low-altitude allele (Epas1LL). These results help us better understand the genetic basis for the unique physiological phenotype of high-altitude natives. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Catherine M Ivy
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Jonathan P Velotta
- Department of Biological Sciences, University of Denver, Denver, CO, 80210, USA
| | - Zachary A Cheviron
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada
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16
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Dawson NJ, Scott GR. Adaptive increases in respiratory capacity and O 2 affinity of subsarcolemmal mitochondria from skeletal muscle of high-altitude deer mice. FASEB J 2022; 36:e22391. [PMID: 35661419 DOI: 10.1096/fj.202200219r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 05/05/2022] [Accepted: 05/23/2022] [Indexed: 11/11/2022]
Abstract
Aerobic energy demands have led to the evolution of complex mitochondrial reticula in highly oxidative muscles, but the extent to which metabolic challenges can be met with adaptive changes in physiology of specific mitochondrial fractions remains unresolved. We examined mitochondrial mechanisms supporting adaptive increases in aerobic performance in deer mice (Peromyscus maniculatus) adapted to the hypoxic environment at high altitude. High-altitude and low-altitude mice were born and raised in captivity, and exposed as adults to normoxia or hypobaric hypoxia (12 kPa O2 for 6-8 weeks). Subsarcolemmal and intermyofibrillar mitochondria were isolated from the gastrocnemius, and a comprehensive substrate titration protocol was used to examine mitochondrial physiology and O2 kinetics by high-resolution respirometry and fluorometry. High-altitude mice had greater yield, respiratory capacity for oxidative phosphorylation, and O2 affinity (lower P50 ) of subsarcolemmal mitochondria compared to low-altitude mice across environments, but there were no species difference in these traits in intermyofibrillar mitochondria. High-altitude mice also had greater capacities of complex II relative to complexes I + II and higher succinate dehydrogenase activities in both mitochondrial fractions. Exposure to chronic hypoxia reduced reactive oxygen species (ROS) emission in high-altitude mice but not in low-altitude mice. Our findings suggest that functional changes in subsarcolemmal mitochondria contribute to improving aerobic performance in hypoxia in high-altitude deer mice. Therefore, physiological variation in specific mitochondrial fractions can help overcome the metabolic challenges of life at high altitude.
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Affiliation(s)
- Neal J Dawson
- Department of Biology, McMaster University, Hamilton, Ontario, Canada.,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
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17
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Lyons SA, McClelland GB. Thermogenesis is supported by high rates of circulatory fatty acid and triglyceride delivery in highland deer mice. J Exp Biol 2022; 225:275398. [PMID: 35552735 DOI: 10.1242/jeb.244080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 05/06/2022] [Indexed: 10/18/2022]
Abstract
Highland native deer mice (Peromyscus maniculatus) have greater rates of lipid oxidation during maximal cold challenge in hypoxia (hypoxic cold-induced V˙O2max) compared to their lowland conspecifics. Lipid oxidation is also increased in deer mice acclimated to simulated high altitude (cold hypoxia), regardless of altitude ancestry. The underlying lipid metabolic pathway traits responsible for sustaining maximal thermogenic demand in deer mice is currently unknown. The objective of this study was to characterize key steps in the lipid oxidation pathway in highland and lowland deer mice acclimated to control (23oC, 21kPa O2) or cold hypoxic (5oC, 12kPa O2) conditions. We hypothesized that capacities for lipid delivery and tissue uptake will be greater in highlanders and further increase with cold hypoxia acclimation. With the transition from rest to hypoxic cold-induced V˙O2max, both highland and lowland deer mice showed increased plasma glycerol concentrations and fatty acid availability. Interestingly, cold hypoxia acclimation led to increased plasma triglyceride concentrations at cold-induced V˙O2max, but only in highlanders. Highlanders also had significantly greater delivery rates of circulatory free fatty acids and triglycerides due to higher plasma flow rates at cold-induced V˙O2max. We found no population or acclimation differences in fatty acid translocase (FAT/CD36) abundance in the gastrocnemius or brown adipose tissue, suggesting fatty acid uptake across membranes is not limiting during thermogenesis. Our data indicate that circulatory lipid delivery plays a major role in supporting the high thermogenic rates observed in highland versus lowland deer mice.
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Affiliation(s)
- Sulayman A Lyons
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Grant B McClelland
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada
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18
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Storz JF, Bautista NM. Altitude acclimatization, hemoglobin-oxygen affinity, and circulatory oxygen transport in hypoxia. Mol Aspects Med 2022; 84:101052. [PMID: 34879970 PMCID: PMC8821351 DOI: 10.1016/j.mam.2021.101052] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/12/2021] [Accepted: 11/15/2021] [Indexed: 01/01/2023]
Abstract
In mammals and other air-breathing vertebrates that live at high altitude, adjustments in convective O2 transport via changes in blood hemoglobin (Hb) content and/or Hb-O2 affinity can potentially mitigate the effects of arterial hypoxemia. However, there are conflicting views about the optimal values of such traits in hypoxia, partly due to the intriguing observation that hypoxia-induced acclimatization responses in humans and other predominantly lowland mammals are frequently not aligned in the same direction as evolved phenotypic changes in high-altitude natives. Here we review relevant theoretical and empirical results and we highlight experimental studies of rodents and humans that provide insights into the combination of hematological changes that help attenuate the decline in aerobic performance in hypoxia. For a given severity of hypoxia, experimental results suggest that optimal values for hematological traits are conditional on the states of other interrelated phenotypes that govern different steps in the O2-transport pathway.
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Affiliation(s)
- Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA.
| | - Naim M Bautista
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA
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19
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Udino E, George JM, McKenzie M, Pessato A, Crino OL, Buchanan KL, Mariette MM. Prenatal acoustic programming of mitochondrial function for high temperatures in an arid-adapted bird. Proc Biol Sci 2021; 288:20211893. [PMID: 34875198 PMCID: PMC8651415 DOI: 10.1098/rspb.2021.1893] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 11/15/2021] [Indexed: 12/16/2022] Open
Abstract
Sound is an essential source of information in many taxa and can notably be used by embryos to programme their phenotypes for postnatal environments. While underlying mechanisms are mostly unknown, there is growing evidence for the involvement of mitochondria-main source of cellular energy (i.e. ATP)-in developmental programming processes. Here, we tested whether prenatal sound programmes mitochondrial metabolism. In the arid-adapted zebra finch, prenatal exposure to 'heat-calls'-produced by parents incubating at high temperatures-adaptively alters nestling growth in the heat. We measured red blood cell mitochondrial function, in nestlings exposed prenatally to heat- or control-calls, and reared in contrasting thermal environments. Exposure to high temperatures always reduced mitochondrial ATP production efficiency. However, as expected to reduce heat production, prenatal exposure to heat-calls improved mitochondrial efficiency under mild heat conditions. In addition, when exposed to an acute heat-challenge, LEAK respiration was higher in heat-call nestlings, and mitochondrial efficiency low across temperatures. Consistent with its role in reducing oxidative damage, LEAK under extreme heat was also higher in fast growing nestlings. Our study therefore provides the first demonstration of mitochondrial acoustic sensitivity, and brings us closer to understanding the underpinning of acoustic developmental programming and avian strategies for heat adaptation.
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Affiliation(s)
- Eve Udino
- School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria 3288, Australia
| | - Julia M. George
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| | - Matthew McKenzie
- School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria 3288, Australia
| | - Anaïs Pessato
- School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria 3288, Australia
| | - Ondi L. Crino
- School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria 3288, Australia
| | - Katherine L. Buchanan
- School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria 3288, Australia
| | - Mylene M. Mariette
- School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria 3288, Australia
- Estación Biológica de Doñana EBD-CSIC, Seville, 41092, Spain
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20
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Yang YZ, Han CY, Jia T, Wang ZK, Zhu WL, Zhang H. Variations of body mass and thermogenesis properties in Eothenomys olitor during cold acclimatization. ANIM BIOL 2021. [DOI: 10.1163/15707563-bja10062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abstract
The set-point hypothesis states that there is a biological control method in mammals that actively regulates weight toward a predetermined set weight for each individual, which may occur by regulation of energy intake or energy expenditure. In order to investigate the effects of low temperature on body mass regulation in Eothenomys olitor, body mass, body fat mass, food intake, resting metabolic rate (RMR), non-shivering thermogenesis (NST), serum leptin levels, morphology, biochemical indexes of liver and brown adipose tissue (BAT) and hypothalamic neuropeptide genes expression were measured during cold acclimatization. The results showed that there was no significant difference in body mass, but food intake, RMR and NST increased during cold acclimatization. Cytochrome c oxidase (COX) and α-glycerophosphate oxidase (α-GPO) activities in liver and BAT were significantly enhanced during cold acclimatization, and triiodothyronine (T3) and thyroxine (T4) levels in serum were significantly higher than those in the control group. Serum leptin levels decreased after cold acclimatization. Low temperature significantly increased the expression of neuropeptide Y (NPY) and agouti-related peptide (AgRP), while it decreased cocaine- and amphetamine-regulated transcript peptide (CART) and pro-opiomelanocortin (POMC) expressions. All of the above results suggested that body mass in E. olitor can remain relatively stable at low temperature, which conforms to the ‘set-point hypothesis’. However, the species showed differences with sympatric species, such as E. miletus, Apodemus chevrieri and Tupaia belangeri. Moreover, E. olitor can cope with low temperature by increasing its metabolic rate and thermogenesis properties.
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Affiliation(s)
- Ya-zuo Yang
- Key Laboratory of Ecological Adaptive Evolution and Conservation on Animals-Plants in Southwest Mountain Ecosystem of Yunnan Province Higher Institutes College, School of Life Science, Yunnan Normal University, Kunming 650500, China
| | - Chun-yan Han
- Key Laboratory of Ecological Adaptive Evolution and Conservation on Animals-Plants in Southwest Mountain Ecosystem of Yunnan Province Higher Institutes College, School of Life Science, Yunnan Normal University, Kunming 650500, China
| | - Ting Jia
- Yunnan College of Business Management, Kunming, 650106, China
| | - Zheng-kun Wang
- Key Laboratory of Ecological Adaptive Evolution and Conservation on Animals-Plants in Southwest Mountain Ecosystem of Yunnan Province Higher Institutes College, School of Life Science, Yunnan Normal University, Kunming 650500, China
| | - Wan-long Zhu
- Key Laboratory of Ecological Adaptive Evolution and Conservation on Animals-Plants in Southwest Mountain Ecosystem of Yunnan Province Higher Institutes College, School of Life Science, Yunnan Normal University, Kunming 650500, China
| | - Hao Zhang
- Key Laboratory of Ecological Adaptive Evolution and Conservation on Animals-Plants in Southwest Mountain Ecosystem of Yunnan Province Higher Institutes College, School of Life Science, Yunnan Normal University, Kunming 650500, China
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21
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Schweizer RM, Jones MR, Bradburd GS, Storz JF, Senner NR, Wolf C, Cheviron ZA. Broad Concordance in the Spatial Distribution of Adaptive and Neutral Genetic Variation across an Elevational Gradient in Deer Mice. Mol Biol Evol 2021; 38:4286-4300. [PMID: 34037784 PMCID: PMC8476156 DOI: 10.1093/molbev/msab161] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
When species are continuously distributed across environmental gradients, the relative strength of selection and gene flow shape spatial patterns of genetic variation, potentially leading to variable levels of differentiation across loci. Determining whether adaptive genetic variation tends to be structured differently than neutral variation along environmental gradients is an open and important question in evolutionary genetics. We performed exome-wide population genomic analysis on deer mice sampled along an elevational gradient of nearly 4,000 m of vertical relief. Using a combination of selection scans, genotype-environment associations, and geographic cline analyses, we found that a large proportion of the exome has experienced a history of altitude-related selection. Elevational clines for nearly 30% of these putatively adaptive loci were shifted significantly up- or downslope of clines for loci that did not bear similar signatures of selection. Many of these selection targets can be plausibly linked to known phenotypic differences between highland and lowland deer mice, although the vast majority of these candidates have not been reported in other studies of highland taxa. Together, these results suggest new hypotheses about the genetic basis of physiological adaptation to high altitude, and the spatial distribution of adaptive genetic variation along environmental gradients.
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Affiliation(s)
- Rena M Schweizer
- Division of Biological Sciences, University of Montana, Missoula, MT, USA
| | - Matthew R Jones
- Division of Biological Sciences, University of Montana, Missoula, MT, USA
- Southwest Biological Science Center, U.S. Geological Survey, Flagstaff, AZ, USA
| | - Gideon S Bradburd
- Ecology, Evolution, and Behavior Program, Department of Integrative Biology, Michigan State University, East Lansing, MI, USA
| | - Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA
| | - Nathan R Senner
- Division of Biological Sciences, University of Montana, Missoula, MT, USA
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Cole Wolf
- Division of Biological Sciences, University of Montana, Missoula, MT, USA
| | - Zachary A Cheviron
- Division of Biological Sciences, University of Montana, Missoula, MT, USA
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22
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Ivy CM, Prest H, West CM, Scott GR. Distinct Mechanisms Underlie Developmental Plasticity and Adult Acclimation of Thermogenic Capacity in High-Altitude Deer Mice. Front Physiol 2021; 12:718163. [PMID: 34456754 PMCID: PMC8385410 DOI: 10.3389/fphys.2021.718163] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/08/2021] [Indexed: 11/13/2022] Open
Abstract
Developmental plasticity can elicit phenotypic adjustments that help organisms cope with environmental change, but the relationship between developmental plasticity and plasticity in adult life (e.g., acclimation) remains unresolved. We sought to examine developmental plasticity and adult acclimation in response to hypoxia of aerobic capacity (V̇O2max) for thermogenesis in deer mice (Peromyscus maniculatus) native to high altitude. Deer mice were bred in captivity and exposed to normoxia or one of four hypoxia treatments (12 kPa O2) across life stages: adult hypoxia (6–8 weeks), post-natal hypoxia (birth to adulthood), life-long hypoxia (before conception to adulthood), and parental hypoxia (mice conceived and raised in normoxia, but parents previously exposed to hypoxia). Hypoxia during perinatal development increased V̇O2max by a much greater magnitude than adult hypoxia. The amplified effect of developmental hypoxia resulted from physiological plasticity that did not occur with adult hypoxia – namely, increases in lung ventilation and volume. Evolved characteristics of deer mice enabled developmental plasticity, because white-footed mice (P. leucopus; a congener restricted to low altitudes) could not raise pups in hypoxia. Parental hypoxia had no persistent effects on V̇O2max. Therefore, developmental plasticity can have much stronger phenotypic effects and can manifest from distinct physiological mechanisms from adult acclimation.
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Affiliation(s)
- Catherine M Ivy
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Haley Prest
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Claire M West
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, ON, Canada
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23
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Scott GR, Dalziel AC. Physiological insight into the evolution of complex phenotypes: aerobic performance and the O2 transport pathway of vertebrates. J Exp Biol 2021; 224:271829. [PMID: 34387318 DOI: 10.1242/jeb.210849] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Evolutionary physiology strives to understand how the function and integration of physiological systems influence the way in which organisms evolve. Studies of the O2 transport pathway - the integrated physiological system that transports O2 from the environment to mitochondria - are well suited to this endeavour. We consider the mechanistic underpinnings across the O2 pathway for the evolution of aerobic capacity, focusing on studies of artificial selection and naturally selected divergence among wild populations of mammals and fish. We show that evolved changes in aerobic capacity do not require concerted changes across the O2 pathway and can arise quickly from changes in one or a subset of pathway steps. Population divergence in aerobic capacity can be associated with the evolution of plasticity in response to environmental variation or activity. In some cases, initial evolutionary divergence of aerobic capacity arose exclusively from increased capacities for O2 diffusion and/or utilization in active O2-consuming tissues (muscle), which may often constitute first steps in adaptation. However, continued selection leading to greater divergence in aerobic capacity is often associated with increased capacities for circulatory and pulmonary O2 transport. Increases in tissue O2 diffusing capacity may augment the adaptive benefit of increasing circulatory O2 transport owing to their interactive influence on tissue O2 extraction. Theoretical modelling of the O2 pathway suggests that O2 pathway steps with a disproportionately large influence over aerobic capacity have been more likely to evolve, but more work is needed to appreciate the extent to which such physiological principles can predict evolutionary outcomes.
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Affiliation(s)
- Graham R Scott
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
| | - Anne C Dalziel
- Department of Biology, Saint Mary's University, 923 Robie Street, Halifax, Nova Scotia, B3H 3C3, Canada
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24
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Wright T, Davis RW, Pearson HC, Murray M, Sheffield-Moore M. Skeletal muscle thermogenesis enables aquatic life in the smallest marine mammal. Science 2021; 373:223-225. [PMID: 34244415 DOI: 10.1126/science.abf4557] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 05/25/2021] [Indexed: 12/19/2022]
Abstract
Basal metabolic rate generally scales with body mass in mammals, and variation from predicted levels indicates adaptive metabolic remodeling. As a thermogenic adaptation for living in cool water, sea otters have a basal metabolic rate approximately three times that of the predicted rate; however, the tissue-level source of this hypermetabolism is unknown. Because skeletal muscle is a major determinant of whole-body metabolism, we characterized respiratory capacity and thermogenic leak in sea otter muscle. Compared with that of previously sampled mammals, thermogenic muscle leak capacity was elevated and could account for sea otter hypermetabolism. Muscle respiratory capacity was modestly elevated and reached adult levels in neonates. Premature metabolic development and high leak rate indicate that sea otter muscle metabolism is regulated by thermogenic demand and is the source of basal hypermetabolism.
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Affiliation(s)
- Traver Wright
- Department of Health and Kinesiology, Texas A&M University, College Station, TX, USA. .,Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA
| | - Randall W Davis
- Department of Marine Biology, Texas A&M University at Galveston, Galveston, TX, USA
| | - Heidi C Pearson
- Department of Natural Sciences, University of Alaska Southeast, Juneau, AK, USA.,College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau, AK, USA
| | | | - Melinda Sheffield-Moore
- Department of Health and Kinesiology, Texas A&M University, College Station, TX, USA.,Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA
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25
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Nord A, Metcalfe NB, Page JL, Huxtable A, McCafferty DJ, Dawson NJ. Avian red blood cell mitochondria produce more heat in winter than in autumn. FASEB J 2021; 35:e21490. [PMID: 33829547 DOI: 10.1096/fj.202100107r] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/13/2021] [Accepted: 02/16/2021] [Indexed: 12/13/2022]
Abstract
Endotherms in cold regions improve heat-producing capacity when preparing for winter. We know comparatively little about how this change is fueled by seasonal adaptation in cellular respiration. Thus, we studied the changes of mitochondrial function in red blood cells in sympatric Coal (Periparus ater), Blue (Cyanistes caeruleus), and Great (Parus major) tits between autumn and winter. These species differ more than twofold in body mass and in several aspects of their foraging ecology and social dominance, which could require differential seasonal adaptation of energy expenditure. Coal and Great tits in particular upregulated the mitochondrial respiration rate and mitochondrial volume in winter. This was not directed toward ATP synthesis, instead reflecting increased uncoupling of electron transport from ATP production. Because uncoupling is exothermic, this increased heat-producing capacity at the sub-cellular level in winter. This previously unexplored the route of thermogenesis in birds should be addressed in future work.
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Affiliation(s)
- Andreas Nord
- Department of Biology, Section for Evolutionary Ecology, Lund University, Lund, Sweden.,Institute of Biodiversity, Animal Health and Comparative Medicine, Scottish Centre for Ecology and the Natural Environment, University of Glasgow, Rowardennan, UK
| | - Neil B Metcalfe
- Institute for Biodiversity, Animal Health and Comparative Medicine, Graham Kerr Building, University of Glasgow, Glasgow, UK
| | - Jennifer L Page
- Institute of Biodiversity, Animal Health and Comparative Medicine, Scottish Centre for Ecology and the Natural Environment, University of Glasgow, Rowardennan, UK
| | - Anna Huxtable
- Institute of Biodiversity, Animal Health and Comparative Medicine, Scottish Centre for Ecology and the Natural Environment, University of Glasgow, Rowardennan, UK
| | - Dominic J McCafferty
- Institute of Biodiversity, Animal Health and Comparative Medicine, Scottish Centre for Ecology and the Natural Environment, University of Glasgow, Rowardennan, UK
| | - Neal J Dawson
- Institute for Biodiversity, Animal Health and Comparative Medicine, Graham Kerr Building, University of Glasgow, Glasgow, UK
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26
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Wearing OH, Scott GR. Commentary: Hierarchical reductionism approach to understanding adaptive variation in animal performance. Comp Biochem Physiol B Biochem Mol Biol 2021; 256:110636. [PMID: 34119652 DOI: 10.1016/j.cbpb.2021.110636] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 06/04/2021] [Accepted: 06/07/2021] [Indexed: 12/20/2022]
Abstract
Aerobic capacity is a complex performance trait with important consequences for fitness, and is determined by the integrated function of the O2 transport pathway. The components of the O2 pathway interact and function as an integrated physiological system, which could strongly influence the contribution of each component to variation in aerobic capacity. In this commentary, we highlight the value of hierarchical reductionism - combining studies of how component parts work in isolation with studies of how components interact within integrated systems - for understanding the evolution of aerobic capacity. This is achieved by focussing on the role of haemoglobin in adaptive increases in aerobic capacity in high-altitude deer mice (Peromyscus maniculatus). High-altitude deer mice have evolved increased aerobic capacity in hypoxia, in association with evolved changes in several subordinate traits across the O2 pathway. This includes an evolved increase in Hb-O2 affinity - which helps safeguard arterial O2 saturation in hypoxia - and reductionist approaches have been successful at identifying the genetic, structural, and biochemical underpinnings of variation in this trait. However, theoretical modelling and empirical measurements suggest that increased Hb-O2 affinity may not augment aerobic capacity on its own. The adaptive benefit of increased Hb-O2 affinity in high-altitude deer mice appears to have been contingent upon antecedent changes in other traits in the O2 pathway, particularly an increased capacity for O2 diffusion and utilization in active tissues. These findings highlight the importance of understanding the interactions between the components of integrated systems for fully appreciating the evolution of complex performance phenotypes.
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Affiliation(s)
- Oliver H Wearing
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada.
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
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27
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Santocildes G, Viscor G, Pagès T, Ramos-Romero S, Torres JL, Torrella JR. Physiological Effects of Intermittent Passive Exposure to Hypobaric Hypoxia and Cold in Rats. Front Physiol 2021; 12:673095. [PMID: 34135770 PMCID: PMC8201611 DOI: 10.3389/fphys.2021.673095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 04/15/2021] [Indexed: 11/25/2022] Open
Abstract
The benefits of intermittent hypobaric hypoxia (IHH) exposure for health and its potential use as a training tool are well-documented. However, since hypobaric hypoxia and cold are environmental factors always strongly associated in the biosphere, additive or synergistic adaptations could have evolved in animals' genomes. For that reason, the aim of the present study was to investigate body composition and hematological and muscle morphofunctional responses to simultaneous intermittent exposure to hypoxia and cold. Adult male rats were randomly divided into four groups: (1) control, maintained in normoxia at 25°C (CTRL); (2) IHH exposed 4 h/day at 4,500 m (HYPO); (3) intermittent cold exposed 4 h/day at 4°C (COLD); and (4) simultaneously cold and hypoxia exposed (COHY). At the end of 9 and 21 days of exposure, blood was withdrawn and gastrocnemius (GAS) and tibialis anterior muscles, perigonadal and brown adipose tissue, diaphragm, and heart were excised. GAS transversal sections were stained for myofibrillar ATPase and succinate dehydrogenase for fiber typing and for endothelial ATPase to assess capillarization. Hypoxia-inducible factor 1α (HIF-1α), vascular endothelial growth factor (VEGF), and glucose transporter 1 (GLUT1) from GAS samples were semi-quantified by Western blotting. COLD and HYPO underwent physiological adjustments such as higher brown adipose tissue weight and increase in blood-related oxygen transport parameters, while avoiding some negative effects of chronic exposure to cold and hypoxia, such as body weight and muscle mass loss. COHY presented an additive erythropoietic response and was prevented from right ventricle hypertrophy. Intermittent cold exposure induced muscle angiogenesis, and IHH seems to indicate better muscle oxygenation through fiber area reduction.
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Affiliation(s)
- Garoa Santocildes
- Secció de Fisiologia, Departament de Biologia Cellular, Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Ginés Viscor
- Secció de Fisiologia, Departament de Biologia Cellular, Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Teresa Pagès
- Secció de Fisiologia, Departament de Biologia Cellular, Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Sara Ramos-Romero
- Secció de Fisiologia, Departament de Biologia Cellular, Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Departament de Química Biològica, Institut de Química Avançada de Catalunya (IQAC-CSIC), Barcelona, Spain
| | - Josep Lluís Torres
- Departament de Química Biològica, Institut de Química Avançada de Catalunya (IQAC-CSIC), Barcelona, Spain
| | - Joan Ramon Torrella
- Secció de Fisiologia, Departament de Biologia Cellular, Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
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28
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Coulson SZ, Robertson CE, Mahalingam S, McClelland GB. Plasticity of non-shivering thermogenesis and brown adipose tissue in high-altitude deer mice. J Exp Biol 2021; 224:268387. [PMID: 34060604 DOI: 10.1242/jeb.242279] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 04/12/2021] [Indexed: 12/22/2022]
Abstract
High altitude environments challenge small mammals with persistent low ambient temperatures that require high rates of aerobic heat production in face of low O2 availability. An important component of thermogenic capacity in rodents is non-shivering thermogenesis (NST) mediated by uncoupled mitochondrial respiration in brown adipose tissue (BAT). NST is plastic, and capacity for heat production increases with cold acclimation. However, in lowland native rodents, hypoxia inhibits NST in BAT. We hypothesize that highland deer mice (Peromyscus maniculatus) overcome the hypoxic inhibition of NST through changes in BAT mitochondrial function. We tested this hypothesis using lab born and raised highland and lowland deer mice, and a lowland congeneric (Peromyscus leucopus), acclimated to either warm normoxia (25°C, 760 mmHg) or cold hypoxia (5°C, 430 mmHg). We determined the effects of acclimation and ancestry on whole-animal rates of NST, the mass of interscapular BAT (iBAT), and uncoupling protein (UCP)-1 protein expression. To identify changes in mitochondrial function, we conducted high-resolution respirometry on isolated iBAT mitochondria using substrates and inhibitors targeted to UCP-1. We found that rates of NST increased with cold hypoxia acclimation but only in highland deer mice. There was no effect of cold hypoxia acclimation on iBAT mass in any group, but highland deer mice showed increases in UCP-1 expression and UCP-1-stimulated mitochondrial respiration in response to these stressors. Our results suggest that highland deer mice have evolved to increase the capacity for NST in response to chronic cold hypoxia, driven in part by changes in iBAT mitochondrial function.
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Affiliation(s)
- Soren Z Coulson
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Cayleih E Robertson
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Sajeni Mahalingam
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Grant B McClelland
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
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29
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Boratyński Z. Energetic constraints on mammalian distribution areas. J Anim Ecol 2021; 90:1854-1863. [PMID: 33884621 DOI: 10.1111/1365-2656.13501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 04/06/2021] [Indexed: 12/01/2022]
Abstract
Energy is a universal resource essential for all life functions. The rate of transformation of energy into an organism, and the energetic investment into reproduction, determines population and ecological-level processes. Several hypotheses predicted that the ecological expansion and size of the geographic distribution of a species are shaped by, among other factors, metabolic performance. However, how organismal energetic characteristics contribute to species geographic range size is poorly understood. With phylogenetic comparative methods whether energetic maintenance costs (basal metabolic rate, BMR), aerobic capacity (maximum exercise metabolic rate, VO2 max), summit thermoregulation (summit metabolic rate, VO2 sum) and the ability to sustain energy provisioning (daily energy expenditure, DEE) determine the distribution of mammalian species range sizes was tested. Both basal and maximum exercise metabolic rates (accounting for body mass), but not summit thermogenic metabolic rate, were positively associated with species range sizes. Furthermore, daily energy expenditure (accounting for body mass) was positively associated with species ranges. Body mass (accounting for energetic maintenance) was negatively related to range sizes. High aerobic exercise capacity, aiding mobility such as running and dispersal, and high sustained energy provisioning, aiding reproductive effort such as pregnancy, lactation and natal dispersal, can facilitate the establishment of large mammalian geographic ranges. Consequently, the pace of organismal physiological processes can shape important ecological and biodiversity patterns by setting limits to species' range sizes.
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Affiliation(s)
- Zbyszek Boratyński
- CIBIO/InBio, Research Centre in Biodiversity and Genetic Resources, University of Porto, Vairão, Portugal
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30
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Storz JF. High-Altitude Adaptation: Mechanistic Insights from Integrated Genomics and Physiology. Mol Biol Evol 2021; 38:2677-2691. [PMID: 33751123 PMCID: PMC8233491 DOI: 10.1093/molbev/msab064] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Population genomic analyses of high-altitude humans and other vertebrates have identified numerous candidate genes for hypoxia adaptation, and the physiological pathways implicated by such analyses suggest testable hypotheses about underlying mechanisms. Studies of highland natives that integrate genomic data with experimental measures of physiological performance capacities and subordinate traits are revealing associations between genotypes (e.g., hypoxia-inducible factor gene variants) and hypoxia-responsive phenotypes. The subsequent search for causal mechanisms is complicated by the fact that observed genotypic associations with hypoxia-induced phenotypes may reflect second-order consequences of selection-mediated changes in other (unmeasured) traits that are coupled with the focal trait via feedback regulation. Manipulative experiments to decipher circuits of feedback control and patterns of phenotypic integration can help identify causal relationships that underlie observed genotype–phenotype associations. Such experiments are critical for correct inferences about phenotypic targets of selection and mechanisms of adaptation.
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Affiliation(s)
- Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA
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31
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Abstract
Population genomic studies of humans and other animals at high altitude have generated many hypotheses about the genes and pathways that may have contributed to hypoxia adaptation. Future advances require experimental tests of such hypotheses to identify causal mechanisms. Studies to date illustrate the challenge of moving from lists of candidate genes to the identification of phenotypic targets of selection, as it can be difficult to determine whether observed genotype-phenotype associations reflect causal effects or secondary consequences of changes in other traits that are linked via homeostatic regulation. Recent work on high-altitude models such as deer mice has revealed both plastic and evolved changes in respiratory, cardiovascular, and metabolic traits that contribute to aerobic performance capacity in hypoxia, and analyses of tissue-specific transcriptomes have identified changes in regulatory networks that mediate adaptive changes in physiological phenotype. Here we synthesize recent results and discuss lessons learned from studies of high-altitude adaptation that lie at the intersection of genomics and physiology.
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Affiliation(s)
- Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588, USA;
| | - Zachary A Cheviron
- Division of Biological Sciences, University of Montana, Missoula, Montana 59812, USA;
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32
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Koch RE, Buchanan KL, Casagrande S, Crino O, Dowling DK, Hill GE, Hood WR, McKenzie M, Mariette MM, Noble DWA, Pavlova A, Seebacher F, Sunnucks P, Udino E, White CR, Salin K, Stier A. Integrating Mitochondrial Aerobic Metabolism into Ecology and Evolution. Trends Ecol Evol 2021; 36:321-332. [PMID: 33436278 DOI: 10.1016/j.tree.2020.12.006] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 12/09/2020] [Accepted: 12/11/2020] [Indexed: 12/17/2022]
Abstract
Biologists have long appreciated the critical role that energy turnover plays in understanding variation in performance and fitness among individuals. Whole-organism metabolic studies have provided key insights into fundamental ecological and evolutionary processes. However, constraints operating at subcellular levels, such as those operating within the mitochondria, can also play important roles in optimizing metabolism over different energetic demands and time scales. Herein, we explore how mitochondrial aerobic metabolism influences different aspects of organismal performance, such as through changing adenosine triphosphate (ATP) and reactive oxygen species (ROS) production. We consider how such insights have advanced our understanding of the mechanisms underpinning key ecological and evolutionary processes, from variation in life-history traits to adaptation to changing thermal conditions, and we highlight key areas for future research.
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Affiliation(s)
- Rebecca E Koch
- Monash University, School of Biological Sciences, Clayton, VIC, 3800, Australia.
| | - Katherine L Buchanan
- Deakin University, School of Life and Environmental Sciences, Waurn Ponds, VIC, 3228, Australia
| | - Stefania Casagrande
- Max Planck Institute for Ornithology, Evolutionary Physiology Group, Seewiesen, Eberhard-Gwinner-Str. Haus 5, 82319, Seewiesen, Germany
| | - Ondi Crino
- Deakin University, School of Life and Environmental Sciences, Waurn Ponds, VIC, 3228, Australia
| | - Damian K Dowling
- Monash University, School of Biological Sciences, Clayton, VIC, 3800, Australia
| | - Geoffrey E Hill
- Auburn University, Department of Biological Sciences, Auburn, AL, 36849, USA
| | - Wendy R Hood
- Auburn University, Department of Biological Sciences, Auburn, AL, 36849, USA
| | - Matthew McKenzie
- Deakin University, School of Life and Environmental Sciences, Waurn Ponds, VIC, 3228, Australia
| | - Mylene M Mariette
- Deakin University, School of Life and Environmental Sciences, Waurn Ponds, VIC, 3228, Australia
| | - Daniel W A Noble
- The Australian National University, Division of Ecology and Evolution, Research School of Biology, Canberra, ACT, 2600, Australia
| | - Alexandra Pavlova
- Monash University, School of Biological Sciences, Clayton, VIC, 3800, Australia
| | - Frank Seebacher
- University of Sydney, School of Life and Environmental Sciences, Sydney, NSW, 2006, Australia
| | - Paul Sunnucks
- Monash University, School of Biological Sciences, Clayton, VIC, 3800, Australia
| | - Eve Udino
- Deakin University, School of Life and Environmental Sciences, Waurn Ponds, VIC, 3228, Australia
| | - Craig R White
- Monash University, School of Biological Sciences, Clayton, VIC, 3800, Australia
| | - Karine Salin
- Université de Brest, Ifremer, CNRS, IRD, Laboratory of Environmental Marine Sciences, Plouzané, 29280, France
| | - Antoine Stier
- University of Turku, Department of Biology, Turku, Finland; University of Glasgow, Institute of Biodiversity, Animal Health and Comparative Medicine, Glasgow, UK
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