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Ingelson-Filpula WA, Storey KB. Hibernation-Induced microRNA Expression Promotes Signaling Pathways and Cell Cycle Dysregulation in Ictidomys tridecemlineatus Cardiac Tissue. Metabolites 2023; 13:1096. [PMID: 37887421 PMCID: PMC10608741 DOI: 10.3390/metabo13101096] [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: 08/30/2023] [Revised: 10/05/2023] [Accepted: 10/16/2023] [Indexed: 10/28/2023] Open
Abstract
The thirteen-lined ground squirrel Ictidomys tridecemlineatus is a rodent that lives throughout the United States and Canada and uses metabolic rate depression to facilitate circannual hibernation which helps it survive the winter. Metabolic rate depression is the reorganization of cellular physiology and molecular biology to facilitate a global downregulation of nonessential genes and processes, which conserves endogenous fuel resources and prevents the buildup of waste byproducts. Facilitating metabolic rate depression requires a complex interplay of regulatory approaches, including post-transcriptional modes such as microRNA. MicroRNA are short, single-stranded RNA species that bind to mRNA transcripts and target them for degradation or translational suppression. Using next-generation sequencing, we analyzed euthermic vs. hibernating cardiac tissue in I. tridecemlineatus to predict seven miRNAs (let-7e-5p, miR-122-5p, miR-2355-3p, miR-6715b-3p, miR-378i, miR-9851-3p, and miR-454-3p) that may be differentially regulated during hibernation. Gene ontology and KEGG pathway analysis suggested that these miRNAs cause a strong activation of ErbB2 signaling which causes downstream effects, including the activation of MAPK and PI3K/Akt signaling and concurrent decreases in p53 signaling and cell cycle-related processes. Taken together, these results predict critical miRNAs that may change during hibernation in the hearts of I. tridecemlineatus and identify key signaling pathways that warrant further study in this species.
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Affiliation(s)
| | - Kenneth B. Storey
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada;
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Hadj-Moussa H, Hawkins LJ, Storey KB. Role of MicroRNAs in Extreme Animal Survival Strategies. Methods Mol Biol 2022; 2257:311-347. [PMID: 34432286 DOI: 10.1007/978-1-0716-1170-8_16] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The critical role microRNAs play in modulating global functions is emerging, both in the maintenance of homeostatic mechanisms and in the adaptation to diverse environmental stresses. When stressed, cells must divert metabolic requirements toward immediate survival and eventual recovery and the unique features of miRNAs, such as their relatively ATP-inexpensive biogenesis costs, and the quick and reversible nature of their action, renders them excellent "master controllers" for rapid responses. Many animal survival strategies for dealing with extreme environmental pressures involve prolonged retreats into states of suspended animation to extend the time that they can survive on their limited internal fuel reserves until conditions improve. The ability to retreat into such hypometabolic states is only possible by coupling the global suppression of nonessential energy-expensive functions with an activation of prosurvival networks, a process in which miRNAs are now known to play a major role. In this chapter, we discuss the activation, expression, biogenesis, and unique attributes of miRNA regulation required to facilitate profound metabolic rate depression and implement stress-specific metabolic adaptations. We examine the role of miRNA in strategies of biochemical adaptation including mammalian hibernation, freeze tolerance, freeze avoidance, anoxia and hypoxia survival, estivation, and dehydration tolerance. By comparing these seemingly different adaptive programs in traditional and exotic animal models, we highlight both unique and conserved miRNA-meditated mechanisms for survival. Additional topics discussed include transcription factor networks, temperature dependent miRNA-targeting, and novel species-specific and stress-specific miRNAs.
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Affiliation(s)
| | - Liam J Hawkins
- Department of Biology, Carleton University, Ottawa, ON, Canada
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Dias IB, Bouma HR, Henning RH. Unraveling the Big Sleep: Molecular Aspects of Stem Cell Dormancy and Hibernation. Front Physiol 2021; 12:624950. [PMID: 33867999 PMCID: PMC8047423 DOI: 10.3389/fphys.2021.624950] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 03/11/2021] [Indexed: 12/14/2022] Open
Abstract
Tissue-resident stem cells may enter a dormant state, also known as quiescence, which allows them to withstand metabolic stress and unfavorable conditions. Similarly, hibernating mammals can also enter a state of dormancy used to evade hostile circumstances, such as food shortage and low ambient temperatures. In hibernation, the dormant state of the individual and its cells is commonly known as torpor, and is characterized by metabolic suppression in individual cells. Given that both conditions represent cell survival strategies, we here compare the molecular aspects of cellular quiescence, particularly of well-studied hematopoietic stem cells, and torpor at the cellular level. Critical processes of dormancy are reviewed, including the suppression of the cell cycle, changes in metabolic characteristics, and cellular mechanisms of dealing with damage. Key factors shared by hematopoietic stem cell quiescence and torpor include a reversible activation of factors inhibiting the cell cycle, a shift in metabolism from glucose to fatty acid oxidation, downregulation of mitochondrial activity, key changes in hypoxia-inducible factor one alpha (HIF-1α), mTOR, reversible protein phosphorylation and autophagy, and increased radiation resistance. This similarity is remarkable in view of the difference in cell populations, as stem cell quiescence regards proliferating cells, while torpor mainly involves terminally differentiated cells. A future perspective is provided how to advance our understanding of the crucial pathways that allow stem cells and hibernating animals to engage in their 'great slumbers.'
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Affiliation(s)
- Itamar B. Dias
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Hjalmar R. Bouma
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
- Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Robert H. Henning
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
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Hadj-Moussa H, Storey KB. The OxymiR response to oxygen limitation: a comparative microRNA perspective. J Exp Biol 2020; 223:223/10/jeb204594. [DOI: 10.1242/jeb.204594] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
ABSTRACT
From squid at the bottom of the ocean to humans at the top of mountains, animals have adapted to diverse oxygen-limited environments. Surviving these challenging conditions requires global metabolic reorganization that is orchestrated, in part, by microRNAs that can rapidly and reversibly target all biological functions. Herein, we review the involvement of microRNAs in natural models of anoxia and hypoxia tolerance, with a focus on the involvement of oxygen-responsive microRNAs (OxymiRs) in coordinating the metabolic rate depression that allows animals to tolerate reduced oxygen levels. We begin by discussing animals that experience acute or chronic periods of oxygen deprivation at the ocean's oxygen minimum zone and go on to consider more elevated environments, up to mountain plateaus over 3500 m above sea level. We highlight the commonalities and differences between OxymiR responses of over 20 diverse animal species, including invertebrates and vertebrates. This is followed by a discussion of the OxymiR adaptations, and maladaptations, present in hypoxic high-altitude environments where animals, including humans, do not enter hypometabolic states in response to hypoxia. Comparing the OxymiR responses of evolutionarily disparate animals from diverse environments allows us to identify species-specific and convergent microRNA responses, such as miR-210 regulation. However, it also sheds light on the lack of a single unified response to oxygen limitation. Characterizing OxymiRs will help us to understand their protective roles and raises the question of whether they can be exploited to alleviate the pathogenesis of ischemic insults and boost recovery. This Review takes a comparative approach to addressing such possibilities.
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Affiliation(s)
- Hanane Hadj-Moussa
- Institute of Biochemistry and Department of Biology, Carleton University, Ottawa, ON, Canada, K1S 5B6
| | - Kenneth B. Storey
- Institute of Biochemistry and Department of Biology, Carleton University, Ottawa, ON, Canada, K1S 5B6
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Al-Attar R, Storey KB. Suspended in time: Molecular responses to hibernation also promote longevity. Exp Gerontol 2020; 134:110889. [PMID: 32114078 DOI: 10.1016/j.exger.2020.110889] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/20/2020] [Accepted: 02/21/2020] [Indexed: 12/16/2022]
Abstract
Aging in most animals is an inevitable process that causes or is a result of physiological, biochemical, and molecular changes in the body, and has a strong influence on an organism's lifespan. Although advancement in medicine has allowed humans to live longer, the prevalence of age-associated medical complications is continuously burdening older adults worldwide. Current animal models used in research to study aging have provided novel information that has helped investigators understand the aging process; however, these models are limiting. Aging is a complex process that is regulated at multiple biological levels, and while a single manipulation in these models can provide information on a process, it is not enough to understand the global regulation of aging. Some mammalian hibernators live up to 9.8-times higher than their expected average lifespan, and new research attributes this increase to their ability to hibernate. A common theme amongst these mammalian hibernators is their ability to greatly reduce their metabolic rate to a fraction of their normal rate and initiate cytoprotective responses that enable their survival. Metabolic rate depression is strictly regulated at different biological levels in order to enable the animal to not only survive, but to also do so by relying mainly on their limited internal fuels. As such, understanding both the global and specific regulatory mechanisms used to promote survival during hibernation could, in theory, allow investigators to have a better understanding of the aging process. This can also allow pharmaceutical industries to find therapeutics that could delay or reverse age-associated medical complications and promote healthy aging and longevity in humans.
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Affiliation(s)
- Rasha Al-Attar
- Institute of Biochemistry and Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada.
| | - Kenneth B Storey
- Institute of Biochemistry and Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada.
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Watts AJ, Storey KB. Hibernation impacts lysine methylation dynamics in the 13-lined ground squirrel, Ictidomys tridecemlineatus. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2019; 331:234-244. [PMID: 30767414 DOI: 10.1002/jez.2259] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 01/21/2019] [Accepted: 01/22/2019] [Indexed: 11/11/2022]
Abstract
During winter hibernation in mammals, body temperature falls to near-ambient levels, metabolism shifts to favor lipid oxidation, and metabolic rate is strongly suppressed by inhibiting many ATP-expensive processes (e.g., transcription, translation) for animals in order to survive for many months on limited reserves of body fuels. Regulation of such profound changes (i.e., metabolic rate depression) requires rapid and reversible controls provided by protein posttranslational modifications. Protein lysine methylation provides one mechanism by which the functionality, activity, and stability of cellular proteins and enzymes can be modified for the needs of the hibernator. The present study reports the responses of seven lysine methyltransferases (SMYD2, SUV39H1, SET8, SET7/9, G9a, ASH2L, and RBBP5) in skeletal muscle and liver over seven stages of the torpor/arousal cycle in 13-lined ground squirrels (Ictidomys tridecemlineatus). A tissue-specific and stage-specific analysis revealed significant changes in the protein levels of lysine methyltransferases, methylation patterns on histone H3, histone methyltransferase activity, and methylation of the p53 transcription factor. Enzymes typically increased in protein amount in either torpor, arousal, or the transitory periods. Methylation of histone H3 and p53 typically followed the patterns of the methyltransferase enzymes. Overall, these data show that protein lysine methylation is an important regulator of the mammalian hibernation phenotype.
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Affiliation(s)
- Alexander J Watts
- Department of Biology, Institute of Biochemistry, Carleton University, Ottawa, Canada
| | - Kenneth B Storey
- Department of Biology, Institute of Biochemistry, Carleton University, Ottawa, Canada
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Logan SM, Wu CW, Storey KB. The squirrel with the lagging eIF2: Global suppression of protein synthesis during torpor. Comp Biochem Physiol A Mol Integr Physiol 2018; 227:161-171. [PMID: 30343059 DOI: 10.1016/j.cbpa.2018.10.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 10/14/2018] [Indexed: 11/17/2022]
Abstract
Hibernating mammals use strong metabolic rate depression and a reduction in body temperature to near-ambient to survive the cold winter months. During torpor, protein synthesis is suppressed but can resume during interbout arousals. The current study aimed to identify molecular targets responsible for the global suppression of protein synthesis during torpor as well as possible mechanisms that could allow for selective protein translation to continue over this time. Relative changes in protein expression and/or phosphorylation levels of key translation factors (ribosomal protein S6, eIF4E, eIF2α, eEF2) and their upstream regulators (mTOR, TSC2, p70 S6K, 4EBP) were analyzed in liver and kidney of 13-lined ground squirrels (Ictidomys tridecemlineatus) sampled from six points over the torpor-arousal cycle. The results indicate that both organs reduce protein synthesis during torpor by decreasing mTOR and TSC2 phosphorylation between 30 and 70% of control levels. Translation resumes during interbout arousal when p-p70 S6K, p-rpS6, and p-4EBP levels returned to control values or above. Only liver translation factors were activated or disinhibited during periods of torpor itself, with >3-fold increases in total eIF2α and eEF2 protein levels, and a decrease in p-eEF2 (T56) to as low as 16% of the euthermic control value. These data shed light on a possible molecular mechanism involving eIF2α that could enable the translation of key transcripts during times of cell stress.
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Affiliation(s)
- Samantha M Logan
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada
| | - Cheng-Wei Wu
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada
| | - Kenneth B Storey
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada.
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Strategies of biochemical adaptation for hibernation in a South American marsupial, Dromiciops gliroides: 3. Activation of pro-survival response pathways. Comp Biochem Physiol B Biochem Mol Biol 2017; 224:26-31. [PMID: 29248591 DOI: 10.1016/j.cbpb.2017.12.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 12/06/2017] [Accepted: 12/07/2017] [Indexed: 12/19/2022]
Abstract
The South American marsupial, monito del monte (Dromiciops gliroides) uses both daily torpor and multi-day hibernation to survive in its southern Chile native environment. The present study leverages multiplex technology to assess the contributions of key stress-inducible cell cycle regulators and heat shock proteins to hibernation in liver, heart, and brain of monito del monte in a comparison of control versus 4day hibernating conditions. The data indicate that MDM2, a stress-responsive ubiquitin ligase, plays a crucial role in marsupial hibernation since all three tissues showed statistically significant increases in MDM2 levels during torpor (1.6-1.8 fold). MDM2 may have a cytoprotective action to deal with ischemia/reperfusion stress and is also involved in a nutrient sensing pathway where it could help regulate the metabolic switch to fatty acid oxidation during torpor. Elevated levels of stress-sensitive cell cycle regulators including ATR (2.32-3.91 fold), and the phosphorylated forms of p-Chk1 (Ser345) (1.92 fold), p-Chk2 (Thr68) (2.20 fold) and p21 (1.64 fold) were observed in heart and liver during hibernation suggesting that the cell cycle is likely suppressed to conserve energy while animals are in torpor. Upregulation of heat shock proteins also occurred as a cytoprotective strategy with increased levels of hsp27 (2.00 fold) and hsp60 (1.72-2.76 fold) during hibernation. The results suggest that cell cycle control and selective chaperone action are significant components of hibernation in D. gliroides and reveal common molecular responses to those seen in eutherian hibernators.
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