1
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Uchino E, Kusumoto-Yoshida I, Kashiwadani H, Kanmura Y, Matsunaga A, Kuwaki T. Identification of hypothermia-inducing neurons in the preoptic area and activation of them by isoflurane anesthesia and central injection of adenosine. J Physiol Sci 2024; 74:33. [PMID: 38867187 PMCID: PMC11167735 DOI: 10.1186/s12576-024-00927-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Accepted: 06/05/2024] [Indexed: 06/14/2024]
Abstract
Hibernation and torpor are not passive responses caused by external temperature drops and fasting but are active brain functions that lower body temperature. A population of neurons in the preoptic area was recently identified as such active torpor-regulating neurons. We hypothesized that the other hypothermia-inducing maneuvers would also activate these neurons. To test our hypothesis, we first refined the previous observations, examined the brain regions explicitly activated during the falling phase of body temperature using c-Fos expression, and confirmed the preoptic area. Next, we observed long-lasting hypothermia by reactivating torpor-tagged Gq-expressing neurons using the activity tagging and DREADD systems. Finally, we found that about 40-60% of torpor-tagged neurons were activated by succeeding isoflurane anesthesia and by icv administration of an adenosine A1 agonist. Isoflurane-induced and central adenosine-induced hypothermia is, at least in part, an active process mediated by the torpor-regulating neurons in the preoptic area.
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Affiliation(s)
- Erika Uchino
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka 8-35-1, Kagoshima, 890-8544, Japan
- Department of Anesthesiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Ikue Kusumoto-Yoshida
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka 8-35-1, Kagoshima, 890-8544, Japan
| | - Hideki Kashiwadani
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka 8-35-1, Kagoshima, 890-8544, Japan
| | - Yuichi Kanmura
- Department of Anesthesiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Akira Matsunaga
- Department of Anesthesiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Tomoyuki Kuwaki
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka 8-35-1, Kagoshima, 890-8544, Japan.
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2
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de Veij Mestdagh CF, Witte ME, Scheper W, Smit AB, Henning RH, van Kesteren RE. Torpor induces reversible tau hyperphosphorylation and accumulation in mice expressing human tau. Acta Neuropathol Commun 2024; 12:86. [PMID: 38835043 PMCID: PMC11149198 DOI: 10.1186/s40478-024-01800-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 05/13/2024] [Indexed: 06/06/2024] Open
Abstract
Tau protein hyperphosphorylation and aggregation are key pathological events in neurodegenerative tauopathies such as Alzheimer's disease. Interestingly, seasonal hibernators show extensive tau hyperphosphorylation during torpor, i.e., the hypothermic and hypometabolic state of hibernation, which is completely reversed during arousal. Torpor-associated mechanisms that reverse tau hyperphosphorylation may be of therapeutic relevance, however, it is currently not known to what extent they apply to human tau. Here we addressed this issue using daily torpor in wildtype mice that express mouse tau (mtau) and in mice that lack mtau expression and instead express human tau (htau). AT8, AT100 and Ser396 immunoblotting and immunohistochemistry were used to assess tau (hyper)phosphorylation at clinically relevant phosphorylation sites. We found that torpor robustly and reversibly increases the levels of phosphorylated tau in both mtau and htau mice. Immunohistochemistry revealed four brain areas that show prominent tau phosphorylation: the hippocampus, posterior parietal cortex, piriform cortex and cortical amygdala. Whereas wildtype mice primarily showed increased levels of diffusely organized hyperphosphorylated tau during torpor, htau mice contained clear somato-dendritic accumulations of AT8 reactivity resembling tau pre-tangles as observed in the Alzheimer brain. Interestingly, AT8-positive accumulations disappeared upon arousal, and tau phosphorylation levels at 24 h after arousal were lower than observed at baseline, suggesting a beneficial effect of torpor-arousal cycles on preexisting hyperphosphorylated tau. In conclusion, daily torpor in mice offers a quick and standardized method to study tau phosphorylation, accumulation and clearance in mouse models relevant for neurodegeneration, as well as opportunities to discover new targets for the treatment of human tauopathies.
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Affiliation(s)
- C F de Veij Mestdagh
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, Groningen, The Netherlands.
- Alzheimer Center Amsterdam, Amsterdam UMC location VUmc, Amsterdam, The Netherlands.
| | - M E Witte
- Department of Molecular Cell Biology and Immunology, MS Center, Amsterdam UMC location VUmc, Amsterdam, The Netherlands
| | - W Scheper
- Department of Human Genetics, Amsterdam UMC - location Vrije Universiteit, Amsterdam, The Netherlands
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - A B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - R H Henning
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, Groningen, The Netherlands
| | - R E van Kesteren
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
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3
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Nakayama D, Makino T. Convergent accelerated evolution of mammal-specific conserved non-coding elements in hibernators. Sci Rep 2024; 14:11754. [PMID: 38782990 PMCID: PMC11116591 DOI: 10.1038/s41598-024-62455-8] [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: 12/05/2023] [Accepted: 05/16/2024] [Indexed: 05/25/2024] Open
Abstract
Mammals maintain their body temperature, yet hibernators can temporarily lower their metabolic rate as an energy-saving strategy. It has been proposed that hibernators evolved independently from homeotherms, and it is possible that the convergent evolution of hibernation involved common genomic changes among hibernator-lineages. Since hibernation is a seasonal trait, the evolution of gene regulatory regions in response to changes in season may have been important for the acquisition of hibernation traits. High-frequency accumulation of mutations in conserved non-coding elements (CNEs) could, in principle, alter the expression of neighboring genes and thereby contribute to the acquisition of new traits. To address this possibility, we performed a comparative genomic analysis of mammals to identify accelerated CNEs commonly associated with hibernation. We found that accelerated CNEs are common to hibernator-lineages and could be involved with hibernation. We also found that common factors of genes that located near accelerated CNEs and are differentially expressed between normal and hibernation periods related to gene regulation and cell-fate determination. It suggests that the molecular mechanisms controlling hibernation have undergone convergent evolution. These results help broaden our understanding of the genetic adaptations that facilitated hibernation in mammals and may offer insights pertaining to stress responses and energy conservation.
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Affiliation(s)
- Daiki Nakayama
- Department of Biology, Faculty of Science, Tohoku University, 6-3, Aramaki Aza Aoba, Aoba-Ku, Sendai, 980-8578, Japan
| | - Takashi Makino
- Department of Biology, Faculty of Science, Tohoku University, 6-3, Aramaki Aza Aoba, Aoba-Ku, Sendai, 980-8578, Japan.
- Graduate School of Life Sciences, Tohoku University, 6-3, Aramaki Aza Aoba, Aoba-Ku, Sendai, 980-8578, Japan.
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4
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Ishimoto T, Kosumi H, Natsuga K, Yamaguchi Y. Nail growth arrest under low body temperature during hibernation. J Physiol Sci 2024; 74:27. [PMID: 38678189 PMCID: PMC11055321 DOI: 10.1186/s12576-024-00919-2] [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: 11/25/2023] [Accepted: 04/06/2024] [Indexed: 04/29/2024]
Abstract
Growth and differentiation are reduced or stopped during hibernation, an energy conserving strategy in harsh seasons by lowered metabolism and body temperature. However, few studies evaluated this in a same individual using a non-invasive method. In this study, we applied a non-invasive tracking method of the nail growth throughout the hibernation period in the same hibernating animals, the Syrian hamster (Mesocricetus auratus). We found that nail growth was markedly suppressed during the hibernation period but rapidly recovered by the exit from the hibernation period. Our data suggest that nail growth was arrested during deep torpor, a hypometabolic and hypothermic state, but recovered during periodic arousal, a euthermic phase. Consistent with this, nail stem cells located in the nail matrix did not exit the cell cycle in the deep torpor. Thus, hibernation stops nail growth in a body temperature-dependent manner.
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Affiliation(s)
- Taiga Ishimoto
- Laboratory of Biochemistry, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
- Department of Neuroscience for Metabolic Control, Graduate School of Medical Science, Kumamoto University, Kumamoto, Japan
| | - Hideyuki Kosumi
- Department of Dermatology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Ken Natsuga
- Department of Dermatology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan.
| | - Yoshifumi Yamaguchi
- Hibernation Metabolism, Physiology and Development Group, Institute of Low Temperature Science, Hokkaido University, Sapporo, Hokkaido, Japan.
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan.
- Inamori Research Institute for Science Fellowship (InaRIS), Kyoto, Japan.
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5
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Jayne L, Lavin-Peter A, Roessler J, Tyshkovskiy A, Antoszewski M, Ren E, Markovski A, Sun S, Yao H, Sankaran VG, Gladyshev VN, Brooke RT, Horvath S, Griffith EC, Hrvatin S. A torpor-like state (TLS) in mice slows blood epigenetic aging and prolongs healthspan. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.20.585828. [PMID: 38585858 PMCID: PMC10996477 DOI: 10.1101/2024.03.20.585828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Torpor and hibernation are extreme physiological adaptations of homeotherms associated with pro-longevity effects. Yet the underlying mechanisms of how torpor affects aging, and whether hypothermic and hypometabolic states can be induced to slow aging and increase health span, remain unknown. We demonstrate that the activity of a spatially defined neuronal population in the avMLPA, which has previously been identified as a torpor-regulating brain region, is sufficient to induce a torpor like state (TLS) in mice. Prolonged induction of TLS slows epigenetic aging across multiple tissues and improves health span. We isolate the effects of decreased metabolic rate, long-term caloric restriction, and decreased core body temperature (Tb) on blood epigenetic aging and find that the pro-longevity effect of torpor-like states is mediated by decreased Tb. Taken together, our findings provide novel mechanistic insight into the pro-longevity effects of torpor and hibernation and support the growing body of evidence that Tb is an important mediator of aging processes.
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Affiliation(s)
- Lorna Jayne
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, 455 Main Street, Cambridge, MA 02142, USA
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115
- Present address: Department of Neurobiology, Stanford University Medical Center, Stanford, CA, USA
| | - Aurora Lavin-Peter
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, 455 Main Street, Cambridge, MA 02142, USA
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115
| | - Julian Roessler
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, 455 Main Street, Cambridge, MA 02142, USA
| | - Alexander Tyshkovskiy
- Division of Genetics, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Mateusz Antoszewski
- Division of Hematology/Oncology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Erika Ren
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115
| | - Aleksandar Markovski
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, 455 Main Street, Cambridge, MA 02142, USA
| | - Senmiao Sun
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115
- Program in Neuroscience, Harvard Medical School, Boston, MA, USA
| | - Hanqi Yao
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115
| | - Vijay G. Sankaran
- Division of Hematology/Oncology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Vadim N. Gladyshev
- Division of Genetics, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, 02115, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | | | - Steve Horvath
- Epigenetic Clock Development Foundation, Torrance, CA, USA
- Altos Labs, Cambridge, UK
| | - Eric C. Griffith
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115
| | - Sinisa Hrvatin
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, 455 Main Street, Cambridge, MA 02142, USA
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6
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Nakagawa S, Yamaguchi Y. Spontaneous recurrence of a summer-like diel rhythm in the body temperature of the Syrian hamster after hibernation. Proc Biol Sci 2023; 290:20230922. [PMID: 37848068 PMCID: PMC10581774 DOI: 10.1098/rspb.2023.0922] [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: 05/02/2023] [Accepted: 09/15/2023] [Indexed: 10/19/2023] Open
Abstract
Mammalian hibernation is a survival strategy characterized by metabolic suppression and drastically lowering body temperature (Tb), used during harsh seasons with food shortages and cold. The Syrian hamster commences hibernation in response to a short photoperiod and cold but spontaneously concludes hibernation after several months without environmental cues. Little is known about the changes in diel rhythms during hibernation. Using long-term and high-resolution Tb data, we analysed the diel Tb rhythm time-course changes in Syrian hamsters raised under summer-like conditions (long photoperiod (LP) and warm; LP-warm) and transferred to winter-like conditions (short photoperiod (SP) and cold; SP-cold). The diel Tb rhythm was undetectable during the hibernation period (HIBP), reappearing after the HIBP. The phase of this returning rhythm reverted to the LP entrainment phase characteristics despite the ambient SP and then re-entrained to the ambient SP as if the hamsters were transferred from the LP-warm to SP-cold conditions. The diel Tb rhythm reverted from the SP- to LP-type in a hibernation-dependent manner. Under constant dark and cold conditions, the circadian Tb rhythm recovered without photic stimuli following the HIBP. These findings suggest that hibernation involves a program that anticipates the ambient photoperiod when animals emerge from hibernation.
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Affiliation(s)
- Satoshi Nakagawa
- Graduate School of Environmental Sciences, Hokkaido University, Sapporo 060-0819, Japan
- Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan
| | - Yoshifumi Yamaguchi
- Graduate School of Environmental Sciences, Hokkaido University, Sapporo 060-0819, Japan
- Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan
- Inamori Research Institute for Science, Kyoto 600-8411, Japan
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7
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Suita K, Ishikawa K, Kaneko M, Wataki A, Takahashi M, Kiyonari H, Sunagawa GA. Mouse embryonic stem cells embody organismal-level cold resistance. Cell Rep 2023; 42:112954. [PMID: 37595588 DOI: 10.1016/j.celrep.2023.112954] [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: 10/21/2022] [Revised: 06/02/2023] [Accepted: 07/22/2023] [Indexed: 08/20/2023] Open
Abstract
During hibernation, some mammals show low body temperatures (<10°C). Tissues from hibernators exhibit cold resistance even when the animal is not hibernating. Mice can also enter hypothermic fasting-induced torpor (FIT), but the cold resistance of FIT has never been related to their tissues. Here, we show that an inbred mouse STM2 exhibits lower body temperature during FIT than C57BL/6J or MYS/Mz. Thus, STM2 resists the cold more than other strains. Analysis of strain-specific mouse embryonic stem (ES) cells shows that STM2 ES cells are more cold-resistant than others and rely on the oxidative phosphorylation (OXPHOS) pathway but respire independently of the electron transfer chain complex I in the cold. We also found that the liver of STM2 uses OXPHOS more in cold than other strains. This study demonstrates that an organismal phenotype associated with torpor can be effectively studied in an in vitro setup using mouse cells.
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Affiliation(s)
- Koukyou Suita
- Laboratory for Retinal Regeneration, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojimaminami-machi, Chuo-ku, Kobe, Hyogo 650-0047, Japan; Laboratory for Molecular Biology of Aging, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojimaminami-machi, Chuo-ku, Kobe, Hyogo 650-0047, Japan; Laboratory for Hibernation Biology, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojimaminami-machi, Chuo-ku, Kobe, Hyogo 650-0047, Japan; Department of Anesthesiology and Resuscitology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1, Shikata-cho, Okayama City, Okayama 700-8558, Japan
| | - Kiyomi Ishikawa
- Laboratory for Retinal Regeneration, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojimaminami-machi, Chuo-ku, Kobe, Hyogo 650-0047, Japan; Laboratory for Molecular Biology of Aging, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojimaminami-machi, Chuo-ku, Kobe, Hyogo 650-0047, Japan; Laboratory for Hibernation Biology, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojimaminami-machi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Mari Kaneko
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojimaminami-machi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Ayaka Wataki
- Laboratory for Retinal Regeneration, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojimaminami-machi, Chuo-ku, Kobe, Hyogo 650-0047, Japan; Laboratory for Molecular Biology of Aging, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojimaminami-machi, Chuo-ku, Kobe, Hyogo 650-0047, Japan; Laboratory for Hibernation Biology, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojimaminami-machi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Masayo Takahashi
- Laboratory for Retinal Regeneration, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojimaminami-machi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Hiroshi Kiyonari
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojimaminami-machi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Genshiro A Sunagawa
- Laboratory for Retinal Regeneration, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojimaminami-machi, Chuo-ku, Kobe, Hyogo 650-0047, Japan; Laboratory for Molecular Biology of Aging, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojimaminami-machi, Chuo-ku, Kobe, Hyogo 650-0047, Japan; Laboratory for Hibernation Biology, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojimaminami-machi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
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8
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Nogueira-de-Sá PG, Bicudo JEPW, Chaui-Berlinck JG. Energy and time optimization during exit from torpor in vertebrate endotherms. J Comp Physiol B 2023:10.1007/s00360-023-01494-5. [PMID: 37171656 DOI: 10.1007/s00360-023-01494-5] [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: 12/09/2022] [Accepted: 04/25/2023] [Indexed: 05/13/2023]
Abstract
Torpor is used in small sized birds and mammals as an energy conservation trait. Considerable effort has been put towards elucidating the mechanisms underlying its entry and maintenance, but little attention has been paid regarding the exit. Firstly, we demonstrate that the arousal phase has a stereotyped dynamic: there is a sharp increase in metabolic rate followed by an increase in body temperature and, then, a damped oscillation in body temperature and metabolism. Moreover, the metabolic peak is around two-fold greater than the corresponding euthermic resting metabolic rate. We then hypothesized that either time or energy could be crucial variables to this event and constructed a model from a collection of first principles of physiology, control engineering and thermodynamics. From the model, we show that the stereotyped pattern of the arousal is a solution to save both time and energy. We extended the analysis to the scaling of the use of torpor by endotherms and show that variables related to the control system of body temperature emerge as relevant to the arousal dynamics. In this sense, the stereotyped dynamics of the arousal phase necessitates a certain profile of these variables which is not maintained as body size increases.
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Affiliation(s)
- Pedro Goes Nogueira-de-Sá
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, Brasil
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9
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Yang Y, Yuan J, Field RL, Ye D, Hu Z, Xu K, Xu L, Gong Y, Yue Y, Kravitz AV, Bruchas MR, Cui J, Brestoff JR, Chen H. Induction of a torpor-like hypothermic and hypometabolic state in rodents by ultrasound. Nat Metab 2023; 5:789-803. [PMID: 37231250 PMCID: PMC10229429 DOI: 10.1038/s42255-023-00804-z,] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 04/11/2023] [Indexed: 08/22/2023]
Abstract
Torpor is an energy-conserving state in which animals dramatically decrease their metabolic rate and body temperature to survive harsh environmental conditions. Here, we report the noninvasive, precise and safe induction of a torpor-like hypothermic and hypometabolic state in rodents by remote transcranial ultrasound stimulation at the hypothalamus preoptic area (POA). We achieve a long-lasting (>24 h) torpor-like state in mice via closed-loop feedback control of ultrasound stimulation with automated detection of body temperature. Ultrasound-induced hypothermia and hypometabolism (UIH) is triggered by activation of POA neurons, involves the dorsomedial hypothalamus as a downstream brain region and subsequent inhibition of thermogenic brown adipose tissue. Single-nucleus RNA-sequencing of POA neurons reveals TRPM2 as an ultrasound-sensitive ion channel, the knockdown of which suppresses UIH. We also demonstrate that UIH is feasible in a non-torpid animal, the rat. Our findings establish UIH as a promising technology for the noninvasive and safe induction of a torpor-like state.
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Affiliation(s)
- Yaoheng Yang
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, USA
| | - Jinyun Yuan
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, USA
| | - Rachael L Field
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO, USA
| | - Dezhuang Ye
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, USA
| | - Zhongtao Hu
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, USA
| | - Kevin Xu
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, USA
| | - Lu Xu
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, USA
| | - Yan Gong
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, USA
| | - Yimei Yue
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, USA
| | - Alexxai V Kravitz
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO, USA
| | - Michael R Bruchas
- Departments of Anesthesiology and Pain Medicine, Pharmacology, and Bioengineering, Center for Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, WA, USA
| | - Jianmin Cui
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, USA
| | - Jonathan R Brestoff
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO, USA
| | - Hong Chen
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, USA.
- Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, MO, USA.
- Department of Neurosurgery, Washington University School of Medicine, St. Louis, MO, USA.
- Division of Neurotechnology, Washington University School of Medicine, Saint Louis, MO, USA.
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10
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Yang Y, Yuan J, Field RL, Ye D, Hu Z, Xu K, Xu L, Gong Y, Yue Y, Kravitz AV, Bruchas MR, Cui J, Brestoff JR, Chen H. Induction of a torpor-like hypothermic and hypometabolic state in rodents by ultrasound. Nat Metab 2023; 5:789-803. [PMID: 37231250 PMCID: PMC10229429 DOI: 10.1038/s42255-023-00804-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 04/11/2023] [Indexed: 05/27/2023]
Abstract
Torpor is an energy-conserving state in which animals dramatically decrease their metabolic rate and body temperature to survive harsh environmental conditions. Here, we report the noninvasive, precise and safe induction of a torpor-like hypothermic and hypometabolic state in rodents by remote transcranial ultrasound stimulation at the hypothalamus preoptic area (POA). We achieve a long-lasting (>24 h) torpor-like state in mice via closed-loop feedback control of ultrasound stimulation with automated detection of body temperature. Ultrasound-induced hypothermia and hypometabolism (UIH) is triggered by activation of POA neurons, involves the dorsomedial hypothalamus as a downstream brain region and subsequent inhibition of thermogenic brown adipose tissue. Single-nucleus RNA-sequencing of POA neurons reveals TRPM2 as an ultrasound-sensitive ion channel, the knockdown of which suppresses UIH. We also demonstrate that UIH is feasible in a non-torpid animal, the rat. Our findings establish UIH as a promising technology for the noninvasive and safe induction of a torpor-like state.
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Affiliation(s)
- Yaoheng Yang
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, USA
| | - Jinyun Yuan
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, USA
| | - Rachael L Field
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO, USA
| | - Dezhuang Ye
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, USA
| | - Zhongtao Hu
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, USA
| | - Kevin Xu
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, USA
| | - Lu Xu
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, USA
| | - Yan Gong
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, USA
| | - Yimei Yue
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, USA
| | - Alexxai V Kravitz
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO, USA
| | - Michael R Bruchas
- Departments of Anesthesiology and Pain Medicine, Pharmacology, and Bioengineering, Center for Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, WA, USA
| | - Jianmin Cui
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, USA
| | - Jonathan R Brestoff
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO, USA
| | - Hong Chen
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, USA.
- Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, MO, USA.
- Department of Neurosurgery, Washington University School of Medicine, St. Louis, MO, USA.
- Division of Neurotechnology, Washington University School of Medicine, Saint Louis, MO, USA.
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11
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Silverman HA, Tynan A, Hepler TD, Chang EH, Gunasekaran M, Li JH, Huerta TS, Tsaava T, Chang Q, Addorisio ME, Chen AC, Thompson DA, Pavlov VA, Brines M, Tracey KJ, Chavan SS. Transient Receptor Potential Ankyrin-1-expressing vagus nerve fibers mediate IL-1β induced hypothermia and reflex anti-inflammatory responses. Mol Med 2023; 29:4. [PMID: 36650454 PMCID: PMC9847185 DOI: 10.1186/s10020-022-00590-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 12/11/2022] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Inflammation, the physiological response to infection and injury, is coordinated by the immune and nervous systems. Interleukin-1β (IL-1β) and other cytokines produced during inflammatory responses activate sensory neurons (nociceptors) to mediate the onset of pain, sickness behavior, and metabolic responses. Although nociceptors expressing Transient Receptor Potential Ankyrin-1 (TRPA1) can initiate inflammation, comparatively little is known about the role of TRPA1 nociceptors in the physiological responses to specific cytokines. METHODS To monitor body temperature in conscious and unrestrained mice, telemetry probes were implanted into peritoneal cavity of mice. Using transgenic and tissue specific knockouts and chemogenetic techniques, we recorded temperature responses to the potent pro-inflammatory cytokine IL-1β. Using calcium imaging, whole cell patch clamping and whole nerve recordings, we investigated the role of TRPA1 during IL-1β-mediated neuronal activation. Mouse models of acute endotoxemia and sepsis were used to elucidate how specific activation, with optogenetics and chemogenetics, or ablation of TRPA1 neurons can affect the outcomes of inflammatory insults. All statistical tests were performed with GraphPad Prism 9 software and for all analyses, P ≤ 0.05 was considered statistically significant. RESULTS Here, we describe a previously unrecognized mechanism by which IL-1β activates afferent vagus nerve fibers to trigger hypothermia, a response which is abolished by selective silencing of neuronal TRPA1. Afferent vagus nerve TRPA1 signaling also inhibits endotoxin-stimulated cytokine storm and significantly reduces the lethality of bacterial sepsis. CONCLUSION Thus, IL-1β activates TRPA1 vagus nerve signaling in the afferent arm of a reflex anti-inflammatory response which inhibits cytokine release, induces hypothermia, and reduces the mortality of infection. This discovery establishes that TRPA1, an ion channel known previously as a pro-inflammatory detector of cold, pain, itch, and a wide variety of noxious molecules, also plays a specific anti-inflammatory role via activating reflex anti-inflammatory activity.
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Affiliation(s)
- Harold A Silverman
- Laboratory for Biomedical Sciences, Institute for Bioelectronic Medicine, Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA
| | - Aisling Tynan
- Laboratory for Biomedical Sciences, Institute for Bioelectronic Medicine, Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA
| | - Tyler D Hepler
- Laboratory for Biomedical Sciences, Institute for Bioelectronic Medicine, Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA
| | - Eric H Chang
- Laboratory for Biomedical Sciences, Institute for Bioelectronic Medicine, Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, 500 Hofstra Blvd, Hempstead, NY, 11549, USA
- The Elmezzi Graduate School of Molecular Medicine, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA
| | - Manojkumar Gunasekaran
- Laboratory for Biomedical Sciences, Institute for Bioelectronic Medicine, Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA
| | - Jian Hua Li
- Laboratory for Biomedical Sciences, Institute for Bioelectronic Medicine, Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA
| | - Tomás S Huerta
- Laboratory for Biomedical Sciences, Institute for Bioelectronic Medicine, Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, 500 Hofstra Blvd, Hempstead, NY, 11549, USA
| | - Tea Tsaava
- Laboratory for Biomedical Sciences, Institute for Bioelectronic Medicine, Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA
| | - Qing Chang
- Laboratory for Biomedical Sciences, Institute for Bioelectronic Medicine, Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA
| | - Meghan E Addorisio
- Laboratory for Biomedical Sciences, Institute for Bioelectronic Medicine, Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA
| | - Adrian C Chen
- Laboratory for Biomedical Sciences, Institute for Bioelectronic Medicine, Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA
| | - Dane A Thompson
- Laboratory for Biomedical Sciences, Institute for Bioelectronic Medicine, Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA
- Department of Surgery, North Shore University Hospital, Northwell Health, 300 Community Drive, Manhasset, NY, 11030, USA
- The Elmezzi Graduate School of Molecular Medicine, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA
| | - Valentin A Pavlov
- Laboratory for Biomedical Sciences, Institute for Bioelectronic Medicine, Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, 500 Hofstra Blvd, Hempstead, NY, 11549, USA
- The Elmezzi Graduate School of Molecular Medicine, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA
| | - Michael Brines
- Laboratory for Biomedical Sciences, Institute for Bioelectronic Medicine, Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA
| | - Kevin J Tracey
- Laboratory for Biomedical Sciences, Institute for Bioelectronic Medicine, Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA.
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, 500 Hofstra Blvd, Hempstead, NY, 11549, USA.
- The Elmezzi Graduate School of Molecular Medicine, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA.
| | - Sangeeta S Chavan
- Laboratory for Biomedical Sciences, Institute for Bioelectronic Medicine, Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA.
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, 500 Hofstra Blvd, Hempstead, NY, 11549, USA.
- The Elmezzi Graduate School of Molecular Medicine, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA.
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12
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SIRT7 suppresses energy expenditure and thermogenesis by regulating brown adipose tissue functions in mice. Nat Commun 2022; 13:7439. [PMID: 36509749 PMCID: PMC9744749 DOI: 10.1038/s41467-022-35219-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 11/23/2022] [Indexed: 12/14/2022] Open
Abstract
Brown adipose tissue plays a central role in the regulation of the energy balance by expending energy to produce heat. NAD+-dependent deacylase sirtuins have widely been recognized as positive regulators of brown adipose tissue thermogenesis. However, here we reveal that SIRT7, one of seven mammalian sirtuins, suppresses energy expenditure and thermogenesis by regulating brown adipose tissue functions. Whole-body and brown adipose tissue-specific Sirt7 knockout mice have higher body temperature and energy expenditure. SIRT7 deficiency increases the protein level of UCP1, a key regulator of brown adipose tissue thermogenesis. Mechanistically, we found that SIRT7 deacetylates insulin-like growth factor 2 mRNA-binding protein 2, an RNA-binding protein that inhibits the translation of Ucp1 mRNA, thereby enhancing its inhibitory action on Ucp1. Furthermore, SIRT7 attenuates the expression of batokine genes, such as fibroblast growth factor 21. In conclusion, we propose that SIRT7 serves as an energy-saving factor by suppressing brown adipose tissue functions.
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13
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Kyo S, Murata K, Kawatou M, Minatoya K, Sunagawa GA, Masumoto H. Quiescence-inducing neurons-induced hypometabolism ameliorates acute kidney injury in a mouse model mimicking cardiovascular surgery requiring circulatory arrest. JTCVS OPEN 2022; 12:201-210. [PMID: 36590714 PMCID: PMC9801336 DOI: 10.1016/j.xjon.2022.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 10/27/2022] [Accepted: 10/31/2022] [Indexed: 11/10/2022]
Abstract
Objectives Acute kidney injury is a serious complication after cardiovascular surgery requiring circulatory arrest. It is reported that mice can be induced into a hibernation-like hypometabolic state by stimulating a specific neuron located at the hypothalamus (quiescence-inducing neurons-induced hypometabolism [QIH]). Here, we investigated the efficacy of QIH for the amelioration of acute kidney injury in an experimental circulatory arrest using a transgenic mouse model. Methods We genetically prepared mice in which QIH can be conditionally induced (QIH-ready mice). Mice were divided into 4 groups (n = 6 for each): QIH-ready normothermia (QN), QIH-ready hypothermia (QH), control normothermia (CN), and control hypothermia (CH). After induction of QIH, left thoracotomy and descending aorta crossclamping were conducted. After reperfusion, we collected kidneys and evaluated histologic changes and serum biochemical markers, specifically neutrophil gelatinase-associated lipocalin and cystatin C, indicating early kidney injury. Results Normothermia showed higher tubular injury scores than those in hypothermia (QN vs QH [P = .0021] and CN vs CH [P < .001]). QN exhibited lower neutrophil gelatinase-associated lipocalin and cystatin C levels than those in CN (neutrophil gelatinase-associated lipocalin: CN vs QN: 1.51 ± 0.71 vs 0.82 ± 0.32; P = .0414 and cystatin C: 1.48 ± 0.39 vs 0.71 ± 0.26; P = .0015). There was no significant difference between QN and QH. Conclusions QIH partly ameliorated acute kidney injury in a mouse ischemia model even in normothermia. QIH might be a promising approach to achieving sufficient kidney protection without hypothermic circulatory arrest in the future.
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Key Words
- AAV8, adeno-associated virus 8
- AKI, acute kidney injury
- CH, control hypothermia
- CN, control normothermia
- CNO, clozapine-N-oxide
- DHCA, deep hypothermic circulatory arrest
- NGAL, neutrophil gelatinase-associated lipocalin
- Q neurons, quiescence-inducing neurons
- Q neurons-induced hypometabolism
- QH, quiescence-inducing neurons-induced hypometabolism-ready hypothermia
- QIH, quiescence-inducing neurons-induced hypometabolism
- QN, quiescence-inducing neurons-induced hypometabolism-ready normothermia
- QRFP, pyroglutamylated RFamide peptide
- TA, ambient temperature
- TB, body temperature
- Vo2, the rate of oxygen consumption
- acute kidney injury
- circulatory arrest
- hibernation
- iCre, codon-improved Cre recombinase
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Affiliation(s)
- Shoichi Kyo
- Department of Cardiovascular Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Kozue Murata
- Department of Cardiovascular Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- Clinical Translational Research Program, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
- Institute for Advancement of Clinical and Translational Science, Kyoto University Hospital, Kyoto, Japan
| | - Masahide Kawatou
- Department of Cardiovascular Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Kenji Minatoya
- Department of Cardiovascular Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Genshiro A. Sunagawa
- Laboratory for Molecular Biology of Aging, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
- Laboratory for Hibernation Biology, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | - Hidetoshi Masumoto
- Department of Cardiovascular Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- Clinical Translational Research Program, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
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14
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Takahashi TM, Hirano A, Kanda T, Saito VM, Ashitomi H, Tanaka KZ, Yokoshiki Y, Masuda K, Yanagisawa M, Vogt KE, Tokuda T, Sakurai T. Optogenetic induction of hibernation-like state with modified human Opsin4 in mice. CELL REPORTS METHODS 2022; 2:100336. [PMID: 36452866 PMCID: PMC9701604 DOI: 10.1016/j.crmeth.2022.100336] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 09/01/2022] [Accepted: 10/19/2022] [Indexed: 05/28/2023]
Abstract
We recently determined that the excitatory manipulation of Qrfp-expressing neurons in the preoptic area of the hypothalamus (quiescence-inducing neurons [Q neurons]) induced a hibernation-like hypothermic/hypometabolic state (QIH) in mice. To control the QIH with a higher time resolution, we develop an optogenetic method using modified human opsin4 (OPN4; also known as melanopsin), a G protein-coupled-receptor-type blue-light photoreceptor. C-terminally truncated OPN4 (OPN4dC) stably and reproducibly induces QIH for at least 24 h by illumination with low-power light (3 μW, 473 nm laser) with high temporal resolution. The high sensitivity of OPN4dC allows us to transcranially stimulate Q neurons with blue-light-emitting diodes and non-invasively induce the QIH. OPN4dC-mediated QIH recapitulates the kinetics of the physiological changes observed in natural hibernation, revealing that Q neurons concurrently contribute to thermoregulation and cardiovascular function. This optogenetic method may facilitate identification of the neural mechanisms underlying long-term dormancy states such as sleep, daily torpor, and hibernation.
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Affiliation(s)
- Tohru M. Takahashi
- Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
- International Integrative Institute for Sleep medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
| | - Arisa Hirano
- Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
- International Integrative Institute for Sleep medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
- JST PRESTO, Japan
| | - Takeshi Kanda
- International Integrative Institute for Sleep medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
| | - Viviane M. Saito
- Memory Research Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Okinawa, Japan
| | - Hiroto Ashitomi
- Memory Research Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Okinawa, Japan
| | - Kazumasa Z. Tanaka
- Memory Research Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Okinawa, Japan
| | - Yasufumi Yokoshiki
- Institute of Innovative Research (IIR), Tokyo Institute of Technology, Tokyo, Japan
| | - Kosaku Masuda
- Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
- International Integrative Institute for Sleep medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
| | - Masashi Yanagisawa
- International Integrative Institute for Sleep medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
| | - Kaspar E. Vogt
- International Integrative Institute for Sleep medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
| | - Takashi Tokuda
- JST PRESTO, Japan
- Institute of Innovative Research (IIR), Tokyo Institute of Technology, Tokyo, Japan
| | - Takeshi Sakurai
- Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
- International Integrative Institute for Sleep medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
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15
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Hypothermia evoked by stimulation of medial preoptic nucleus protects the brain in a mouse model of ischaemia. Nat Commun 2022; 13:6890. [PMID: 36371436 PMCID: PMC9653397 DOI: 10.1038/s41467-022-34735-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 11/04/2022] [Indexed: 11/13/2022] Open
Abstract
Therapeutic hypothermia at 32-34 °C during or after cerebral ischaemia is neuroprotective. However, peripheral cold sensor-triggered hypothermia is ineffective and evokes vigorous counteractive shivering thermogenesis and complications that are difficult to tolerate in awake patients. Here, we show in mice that deep brain stimulation (DBS) of warm-sensitive neurones (WSNs) in the medial preoptic nucleus (MPN) produces tolerable hypothermia. In contrast to surface cooling-evoked hypothermia, DBS mice exhibit a torpor-like state without counteractive shivering. Like hypothermia evoked by chemogenetic activation of WSNs, DBS in free-moving mice elicits a rapid lowering of the core body temperature to 32-34 °C, which confers significant brain protection and motor function reservation. Mechanistically, activation of WSNs contributes to DBS-evoked hypothermia. Inhibition of WSNs prevents DBS-evoked hypothermia. Maintaining the core body temperature at normothermia during DBS abolishes DBS-mediated brain protection. Thus, the MPN is a DBS target to evoke tolerable therapeutic hypothermia for stroke treatment.
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16
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HORII Y, OKADERA K, MIYAWAKI S, SHIINA T, SHIMIZU Y. <i>Suncus murinus</i> as a novel model animal that is suitable for elucidating the mechanism of daily torpor. Biomed Res 2022; 43:53-57. [DOI: 10.2220/biomedres.43.53] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Yuuki HORII
- Laboratory of Veterinary Physiology, Faculty of Applied Biological Sciences, Gifu University
| | - Kanako OKADERA
- Laboratory of Veterinary Physiology, Faculty of Applied Biological Sciences, Gifu University
| | - Shingo MIYAWAKI
- Laboratory of Veterinary Surgery, Faculty of Applied Biological Sciences, Gifu University
| | - Takahiko SHIINA
- Laboratory of Veterinary Physiology, Faculty of Applied Biological Sciences, Gifu University
| | - Yasutake SHIMIZU
- Laboratory of Veterinary Physiology, Faculty of Applied Biological Sciences, Gifu University
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17
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Ambler M, Hitrec T, Pickering A. Turn it off and on again: characteristics and control of torpor. Wellcome Open Res 2022; 6:313. [PMID: 35087956 PMCID: PMC8764563 DOI: 10.12688/wellcomeopenres.17379.2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2022] [Indexed: 11/20/2022] Open
Abstract
Torpor is a hypothermic, hypoactive, hypometabolic state entered into by a wide range of animals in response to environmental challenge. This review summarises the current understanding of torpor. We start by describing the characteristics of the wide-ranging physiological adaptations associated with torpor. Next follows a discussion of thermoregulation, control of food intake and energy expenditure, and the interactions of sleep and thermoregulation, with particular emphasis on how those processes pertain to torpor. We move on to review the evidence for the systems that control torpor entry, including both the efferent circulating factors that signal the need for torpor, and the central processes that orchestrate it. Finally, we consider how the putative circuits responsible for torpor induction integrate with the established understanding of thermoregulation under non-torpid conditions and highlight important areas of uncertainty for future studies.
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Affiliation(s)
- Michael Ambler
- School of Physiology, Pharmacology, & Neuroscience, University of Bristol, Bristol, Bristol, BS8 1TD, UK
| | - Timna Hitrec
- School of Physiology, Pharmacology, & Neuroscience, University of Bristol, Bristol, Bristol, BS8 1TD, UK
| | - Anthony Pickering
- School of Physiology, Pharmacology, & Neuroscience, University of Bristol, Bristol, Bristol, BS8 1TD, UK
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18
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Taiji S, Nishino T, Jin H, Shinozuka N, Nozaki‐Taguchi N, Isono S. Changes in breathing pattern during severe hypothermia and autoresuscitation from hypothermic respiratory arrest in anesthetized mice. Physiol Rep 2021; 9:e15139. [PMID: 34898045 PMCID: PMC8666628 DOI: 10.14814/phy2.15139] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 11/19/2021] [Accepted: 11/20/2021] [Indexed: 11/24/2022] Open
Abstract
Some evidence suggests that both hypothermia and anesthesia can exert similar effects on metabolism and ventilation. This study examined the synergistic effects of anesthesia and hypothermia on ventilation in spontaneously breathing adult mice under three different conditions, that is, (1) pentobarbital group (n = 7) in which mice were anesthetized with intraperitoneal pentobarbital of 80 mg/kg, (2) sevoflurane-continued group (n = 7) in which mice were anesthetized with 1 MAC sevoflurane, and (3) sevoflurane-discontinued group (n = 7) in which sevoflurane was discontinued at a body temperature below 22˚C. We cooled mice in each group until breathing ceased and followed this with artificial rewarming while measuring changes in respiratory variables and heart rate. We found that the body temperature at which respiration arrested is much lower in the sevoflurane-discontinued group (13.8 ± 2.0˚C) than that in the sevoflurane-continued group (16.7 ± 1.2˚C) and the pentobarbital group (17.0 ± 1.4˚C). Upon rewarming, all animals in all three groups spontaneously recovered from respiratory arrest. There was a considerable difference in breathing patterns between sevoflurane-anesthetized mice and pentobarbital-anesthetized mice during progressive hypothermia in terms of changes in tidal volume and respiratory frequency. The changes in the respiratory pattern during rewarming are nearly mirrored images of the changes observed during cooling in all three groups. These observations indicate that adult mice are capable of autoresuscitation from hypothermic respiratory arrest and that anesthesia and hypothermia exert synergistic effects on the occurrence of respiratory arrest while the type of anesthetic affects the breathing pattern that occurs during progressive hypothermia leading to respiratory arrest.
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Affiliation(s)
- Saki Taiji
- Department of AnesthesiologyGraduate School of MedicineChiba UniversityChibaJapan
| | - Takashi Nishino
- Department of AnesthesiologyGraduate School of MedicineChiba UniversityChibaJapan
| | - Hisayo Jin
- Department of AnesthesiologyGraduate School of MedicineChiba UniversityChibaJapan
| | | | | | - Shiroh Isono
- Department of AnesthesiologyGraduate School of MedicineChiba UniversityChibaJapan
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19
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Ambler M, Hitrec T, Pickering A. Turn it off and on again: characteristics and control of torpor. Wellcome Open Res 2021; 6:313. [DOI: 10.12688/wellcomeopenres.17379.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/12/2021] [Indexed: 11/20/2022] Open
Abstract
Torpor is a hypothermic, hypoactive, hypometabolic state entered into by a wide range of animals in response to environmental challenge. This review summarises the current understanding of torpor. We start by describing the characteristics of the wide-ranging physiological adaptations associated with torpor. Next follows a discussion of thermoregulation, control of food intake and energy expenditure, and the interactions of sleep and thermoregulation, with particular emphasis on how those processes pertain to torpor. We move on to take a critical view of the evidence for the systems that control torpor entry, including both the efferent circulating factors that signal the need for torpor, and the central processes that orchestrate it. Finally, we consider how the putative circuits responsible for torpor induction integrate with the established understanding of thermoregulation under non-torpid conditions and highlight important areas of uncertainty for future studies.
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20
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Integrative transcription start site analysis and physiological phenotyping reveal torpor-specific expression program in mouse skeletal muscle. Commun Biol 2021; 4:1290. [PMID: 34782710 PMCID: PMC8592991 DOI: 10.1038/s42003-021-02819-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 10/28/2021] [Indexed: 11/30/2022] Open
Abstract
Mice enter an active hypometabolic state, called daily torpor when they experience a lowered caloric intake under cold ambient temperature. During torpor, the oxygen consumption rate in some animals drops to less than 30% of the normal rate without harming the body. This safe but severe reduction in metabolism is attractive for various clinical applications; however, the mechanism and molecules involved are unclear. Therefore, here we systematically analyzed the gene expression landscape on the level of the RNA transcription start sites in mouse skeletal muscles under various metabolic states to identify torpor-specific transcribed regulatory patterns. We analyzed the soleus muscles from 38 mice in torpid and non-torpid conditions and identified 287 torpor-specific promoters out of 12,862 detected promoters. Furthermore, we found that the transcription factor ATF3 is highly expressed during torpor deprivation and its binding motif is enriched in torpor-specific promoters. Atf3 was also highly expressed in the heart and brown adipose tissue during torpor and systemically knocking out Atf3 affected the torpor phenotype. Our results demonstrate that mouse torpor combined with powerful genetic tools is useful for studying active hypometabolism.
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21
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Huang YG, Flaherty SJ, Pothecary CA, Foster RG, Peirson SN, Vyazovskiy VV. The relationship between fasting-induced torpor, sleep, and wakefulness in laboratory mice. Sleep 2021; 44:zsab093. [PMID: 33838033 PMCID: PMC8436144 DOI: 10.1093/sleep/zsab093] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 04/03/2021] [Indexed: 11/30/2022] Open
Abstract
STUDY OBJECTIVES Torpor is a regulated and reversible state of metabolic suppression used by many mammalian species to conserve energy. Whereas the relationship between torpor and sleep has been well-studied in seasonal hibernators, less is known about the effects of fasting-induced torpor on states of vigilance and brain activity in laboratory mice. METHODS Continuous monitoring of electroencephalogram (EEG), electromyogram (EMG), and surface body temperature was undertaken in adult, male C57BL/6 mice over consecutive days of scheduled restricted feeding. RESULTS All animals showed bouts of hypothermia that became progressively deeper and longer as fasting progressed. EEG and EMG were markedly affected by hypothermia, although the typical electrophysiological signatures of non-rapid eye movement (NREM) sleep, rapid eye movement (REM) sleep, and wakefulness enabled us to perform vigilance-state classification in all cases. Consistent with previous studies, hypothermic bouts were initiated from a state indistinguishable from NREM sleep, with EEG power decreasing gradually in parallel with decreasing surface body temperature. During deep hypothermia, REM sleep was largely abolished, and we observed shivering-associated intense bursts of muscle activity. CONCLUSIONS Our study highlights important similarities between EEG signatures of fasting-induced torpor in mice, daily torpor in Djungarian hamsters and hibernation in seasonally hibernating species. Future studies are necessary to clarify the effects on fasting-induced torpor on subsequent sleep.
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Affiliation(s)
- Yi-Ge Huang
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT,UK
| | - Sarah J Flaherty
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT,UK
| | - Carina A Pothecary
- Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, Oxford Molecular Pathology Institute, Sir William Dunn School of Pathology, South Parks Road, Oxford OX1 3RE,UK
| | - Russell G Foster
- Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, Oxford Molecular Pathology Institute, Sir William Dunn School of Pathology, South Parks Road, Oxford OX1 3RE,UK
| | - Stuart N Peirson
- Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, Oxford Molecular Pathology Institute, Sir William Dunn School of Pathology, South Parks Road, Oxford OX1 3RE,UK
| | - Vladyslav V Vyazovskiy
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT,UK
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22
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Harrison XA. A brief introduction to the analysis of time-series data from biologging studies. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200227. [PMID: 34176325 PMCID: PMC8237163 DOI: 10.1098/rstb.2020.0227] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/29/2021] [Indexed: 12/24/2022] Open
Abstract
Recent advances in tagging and biologging technology have yielded unprecedented insights into wild animal physiology. However, time-series data from such wild tracking studies present numerous analytical challenges owing to their unique nature, often exhibiting strong autocorrelation within and among samples, low samples sizes and complicated random effect structures. Gleaning robust quantitative estimates from these physiological data, and, therefore, accurate insights into the life histories of the animals they pertain to, requires careful and thoughtful application of existing statistical tools. Using a combination of both simulated and real datasets, I highlight the key pitfalls associated with analysing physiological data from wild monitoring studies, and investigate issues of optimal study design, statistical power, and model precision and accuracy. I also recommend best practice approaches for dealing with their inherent limitations. This work will provide a concise, accessible roadmap for researchers looking to maximize the yield of information from complex and hard-won biologging datasets. This article is part of the theme issue 'Measuring physiology in free-living animals (Part II)'.
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Affiliation(s)
- Xavier A. Harrison
- Centre for Ecology and Conservation, University of Exeter, Penryn TR10 9FE, UK
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23
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Shi Z, Qin M, Huang L, Xu T, Chen Y, Hu Q, Peng S, Peng Z, Qu LN, Chen SG, Tuo QH, Liao DF, Wang XP, Wu RR, Yuan TF, Li YH, Liu XM. Human torpor: translating insights from nature into manned deep space expedition. Biol Rev Camb Philos Soc 2020; 96:642-672. [PMID: 33314677 DOI: 10.1111/brv.12671] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/09/2020] [Accepted: 11/17/2020] [Indexed: 12/12/2022]
Abstract
During a long-duration manned spaceflight mission, such as flying to Mars and beyond, all crew members will spend a long period in an independent spacecraft with closed-loop bioregenerative life-support systems. Saving resources and reducing medical risks, particularly in mental heath, are key technology gaps hampering human expedition into deep space. In the 1960s, several scientists proposed that an induced state of suppressed metabolism in humans, which mimics 'hibernation', could be an ideal solution to cope with many issues during spaceflight. In recent years, with the introduction of specific methods, it is becoming more feasible to induce an artificial hibernation-like state (synthetic torpor) in non-hibernating species. Natural torpor is a fascinating, yet enigmatic, physiological process in which metabolic rate (MR), body core temperature (Tb ) and behavioural activity are reduced to save energy during harsh seasonal conditions. It employs a complex central neural network to orchestrate a homeostatic state of hypometabolism, hypothermia and hypoactivity in response to environmental challenges. The anatomical and functional connections within the central nervous system (CNS) lie at the heart of controlling synthetic torpor. Although progress has been made, the precise mechanisms underlying the active regulation of the torpor-arousal transition, and their profound influence on neural function and behaviour, which are critical concerns for safe and reversible human torpor, remain poorly understood. In this review, we place particular emphasis on elaborating the central nervous mechanism orchestrating the torpor-arousal transition in both non-flying hibernating mammals and non-hibernating species, and aim to provide translational insights into long-duration manned spaceflight. In addition, identifying difficulties and challenges ahead will underscore important concerns in engineering synthetic torpor in humans. We believe that synthetic torpor may not be the only option for manned long-duration spaceflight, but it is the most achievable solution in the foreseeable future. Translating the available knowledge from natural torpor research will not only benefit manned spaceflight, but also many clinical settings attempting to manipulate energy metabolism and neurobehavioural functions.
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Affiliation(s)
- Zhe Shi
- National Clinical Research Center for Mental Disorders, and Department of Psychaitry, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China.,Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China.,State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China.,Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, Shanghai, 200030, China
| | - Meng Qin
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Lu Huang
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou, 510632, China
| | - Tao Xu
- Department of Anesthesiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Ying Chen
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Qin Hu
- College of Life Sciences and Bio-Engineering, Beijing University of Technology, Beijing, 100024, China
| | - Sha Peng
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Zhuang Peng
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Li-Na Qu
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
| | - Shan-Guang Chen
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
| | - Qin-Hui Tuo
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Duan-Fang Liao
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Xiao-Ping Wang
- National Clinical Research Center for Mental Disorders, and Department of Psychaitry, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China
| | - Ren-Rong Wu
- National Clinical Research Center for Mental Disorders, and Department of Psychaitry, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China
| | - Ti-Fei Yuan
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, Shanghai, 200030, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226000, China
| | - Ying-Hui Li
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
| | - Xin-Min Liu
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China.,State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China.,Research Center for Pharmacology and Toxicology, Institute of Medicinal Plant Development (IMPLAD), Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100193, China
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24
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Hrvatin S, Sun S, Wilcox OF, Yao H, Lavin-Peter AJ, Cicconet M, Assad EG, Palmer ME, Aronson S, Banks AS, Griffith EC, Greenberg ME. Neurons that regulate mouse torpor. Nature 2020; 583:115-121. [PMID: 32528180 DOI: 10.1038/s41586-020-2387-5] [Citation(s) in RCA: 119] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 05/07/2020] [Indexed: 12/27/2022]
Abstract
The advent of endothermy, which is achieved through the continuous homeostatic regulation of body temperature and metabolism1,2, is a defining feature of mammalian and avian evolution. However, when challenged by food deprivation or harsh environmental conditions, many mammalian species initiate adaptive energy-conserving survival strategies-including torpor and hibernation-during which their body temperature decreases far below its homeostatic set-point3-5. How homeothermic mammals initiate and regulate these hypothermic states remains largely unknown. Here we show that entry into mouse torpor, a fasting-induced state with a greatly decreased metabolic rate and a body temperature as low as 20 °C6, is regulated by neurons in the medial and lateral preoptic area of the hypothalamus. We show that restimulation of neurons that were activated during a previous bout of torpor is sufficient to initiate the key features of torpor, even in mice that are not calorically restricted. Among these neurons we identify a population of glutamatergic Adcyap1-positive cells, the activity of which accurately determines when mice naturally initiate and exit torpor, and the inhibition of which disrupts the natural process of torpor entry, maintenance and arousal. Taken together, our results reveal a specific neuronal population in the mouse hypothalamus that serves as a core regulator of torpor. This work forms a basis for the future exploration of mechanisms and circuitry that regulate extreme hypothermic and hypometabolic states, and enables genetic access to monitor, initiate, manipulate and study these ancient adaptations of homeotherm biology.
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Affiliation(s)
- Sinisa Hrvatin
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA.
| | - Senmiao Sun
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA.,Program in Neuroscience, Harvard Medical School, Boston, MA, USA
| | - Oren F Wilcox
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Hanqi Yao
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | | | - Marcelo Cicconet
- Image and Data Analysis Core, Harvard Medical School, Boston, MA, USA
| | - Elena G Assad
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | | | | | - Alexander S Banks
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Eric C Griffith
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
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25
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Takahashi TM, Sunagawa GA, Soya S, Abe M, Sakurai K, Ishikawa K, Yanagisawa M, Hama H, Hasegawa E, Miyawaki A, Sakimura K, Takahashi M, Sakurai T. A discrete neuronal circuit induces a hibernation-like state in rodents. Nature 2020; 583:109-114. [PMID: 32528181 DOI: 10.1038/s41586-020-2163-6] [Citation(s) in RCA: 121] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 03/04/2020] [Indexed: 02/07/2023]
Abstract
Hibernating mammals actively lower their body temperature to reduce energy expenditure when facing food scarcity1. This ability to induce a hypometabolic state has evoked great interest owing to its potential medical benefits2,3. Here we show that a hypothalamic neuronal circuit in rodents induces a long-lasting hypothermic and hypometabolic state similar to hibernation. In this state, although body temperature and levels of oxygen consumption are kept very low, the ability to regulate metabolism still remains functional, as in hibernation4. There was no obvious damage to tissues and organs or abnormalities in behaviour after recovery from this state. Our findings could enable the development of a method to induce a hibernation-like state, which would have potential applications in non-hibernating mammalian species including humans.
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Affiliation(s)
- Tohru M Takahashi
- Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.,International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
| | - Genshiro A Sunagawa
- Laboratory for Retinal Regeneration, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan.
| | - Shingo Soya
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
| | - Manabu Abe
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata, Japan.,Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata, Japan
| | - Katsuyasu Sakurai
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
| | - Kiyomi Ishikawa
- Laboratory for Retinal Regeneration, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | - Masashi Yanagisawa
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
| | - Hiroshi Hama
- Laboratory for Cell Function Dynamics, RIKEN Center for Brain Science, Wako, Japan
| | - Emi Hasegawa
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
| | - Atsushi Miyawaki
- Laboratory for Cell Function Dynamics, RIKEN Center for Brain Science, Wako, Japan
| | - Kenji Sakimura
- Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata, Japan
| | - Masayo Takahashi
- Laboratory for Retinal Regeneration, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | - Takeshi Sakurai
- Faculty of Medicine, University of Tsukuba, Tsukuba, Japan. .,International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan. .,Life Science Center, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Japan.
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26
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Morita H, Kaji H, Ueta Y, Abe C. Understanding vestibular-related physiological functions could provide clues on adapting to a new gravitational environment. J Physiol Sci 2020; 70:17. [PMID: 32169037 PMCID: PMC7069930 DOI: 10.1186/s12576-020-00744-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 03/03/2020] [Indexed: 12/16/2022]
Abstract
The peripheral vestibular organs are sensors for linear acceleration (gravity and head tilt) and rotation. Further, they regulate various body functions, including body stability, ocular movement, autonomic nerve activity, arterial pressure, body temperature, and muscle and bone metabolism. The gravitational environment influences these functions given the highly plastic responsiveness of the vestibular system. This review demonstrates that hypergravity or microgravity induces changes in vestibular-related physiological functions, including arterial pressure, muscle and bone metabolism, feeding behavior, and body temperature. Hopefully, this review contributes to understanding how human beings can adapt to a new gravitational environment, including the moon and Mars, in future.
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Affiliation(s)
- Hironobu Morita
- Department of Physiology, Gifu University Graduate School of Medicine, Gifu, 501-1194, Japan.
| | - Hiroshi Kaji
- Department of Physiology and Regenerative Medicine, Faculty of Medicine, Kindai University, Osakasayama, 589-8511, Japan
| | - Yoichi Ueta
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, 807-8555, Japan
| | - Chikara Abe
- Department of Physiology, Gifu University Graduate School of Medicine, Gifu, 501-1194, Japan
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27
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Griko Y, Palma E, Galicia E, Selch F. Factors limiting the duration of artificially induced torpor in mice. LIFE SCIENCES IN SPACE RESEARCH 2020; 24:34-41. [PMID: 31987478 DOI: 10.1016/j.lssr.2019.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 09/25/2019] [Accepted: 10/24/2019] [Indexed: 06/10/2023]
Abstract
The possibility of artificial induction of a torpid state in animals that do not naturally do so, as well as in humans, offers a great potential in biomedicine and in human spaceflight. However, the mechanisms of action that provide a coordinated and concomitant downregulation with a safe recovery from this state are poorly understood. In our previous study, we demonstrated that the metabolic rate of mice can be reduced by nearly 94% and can remain stable under hypothermic conditions for a prolonged period of up to 11 h. The present study was carried out in order to test the limitations and identify potential factors that can enable the safe and reversible arousal of non-hibernating mice from deep artificially-induced torpor to an active state. Results demonstrate that the energy budget may be a limiting factor for the prolongation and safe recovery from the hypometabolic state. While the continuation of torpor may be possible for additional hours, we found that a reduction of 40% or more in the plasma glucose level increases the risk of heart fibrillation, which results in death during arousal. Therefore, the plasma glucose level could be a component of the criteria indicating the reversibility of torpor. Another important factor complementing the energetic necessity that may limit the duration of torpor in mice is a gradual reduction in body mass during torpor. Under the conditions of our experiment, body mass declines by nearly 15% after 16 h from the initiation of torpor and may continue to decline if the mice are allowed to remain in torpor longer. Extrapolation of this data suggests that there may be a critical mass relating to animal mortality and thus limiting the duration of torpor. Control and maintenance of the body mass and glucose level in a torpid animal may extend the longevity of torpor and mitigate the risk of cardiac failure during rewarming to the metabolically active state. The cardiac complications that occur during arousal from torpor in many cases could be mitigated and even avoided by applying appropriate temperature-arising kinetics and providing a sufficient dynamic range to maintain cardiac output.
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Affiliation(s)
- Yuri Griko
- National Aeronautics and Space Administration, Ames Research Center, Moffett Field, CA 94035 USA.
| | - Ervin Palma
- California State University, East Bay, Hayward, CA 94542, United States
| | - Eugene Galicia
- Carnegie Mellon University Silicon Valley, Moffett Field CA 94035, United States
| | - Florian Selch
- Carnegie Mellon University Silicon Valley, Moffett Field CA 94035, United States
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28
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Calonne J, Arsenijevic D, Scerri I, Miles-Chan JL, Montani JP, Dulloo AG. Low 24-hour core body temperature as a thrifty metabolic trait driving catch-up fat during weight regain after caloric restriction. Am J Physiol Endocrinol Metab 2019; 317:E699-E709. [PMID: 31430205 DOI: 10.1152/ajpendo.00092.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The recovery of body weight after substantial weight loss or growth retardation is often characterized by a disproportionately higher rate of fat mass vs. lean mass recovery, with this phenomenon of "preferential catch-up fat" being contributed by energy conservation (thrifty) metabolism. To test the hypothesis that a low core body temperature (Tc) constitutes a thrifty metabolic trait underlying the high metabolic efficiency driving catch-up fat, the Anipill system, with telemetry capsules implanted in the peritoneal cavity, was used for continuous monitoring of Tc for several weeks in a validated rat model of semistarvation-refeeding in which catch-up fat is driven solely by suppressed thermogenesis. In animals housed at 22°C, 24-h Tc was reduced in response to semistarvation (-0.77°C, P < 0.001) and remained significantly lower than in control animals during the catch-up fat phase of refeeding (-0.27°C on average, P < 0.001), the lower Tc during refeeding being more pronounced during the light phase than during the dark phase of the 24-h cycle (-0.30°C vs. -0.23°C, P < 0.01) and with no between-group differences in locomotor activity. A lower 24-h Tc in animals showing catch-up fat was also observed when the housing temperature was raised to 29°C (i.e., at thermoneutrality). The reduced energy cost of homeothermy in response to caloric restriction persists during weight recovery and constitutes a thrifty metabolic trait that contributes to the high metabolic efficiency that underlies the rapid restoration of the body's fat stores during weight regain, with implications for obesity relapse after therapeutic slimming and the pathophysiology of catch-up growth.
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Affiliation(s)
- Julie Calonne
- Department of Endocrinology, Metabolism and Cardiovascular System, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Denis Arsenijevic
- Department of Endocrinology, Metabolism and Cardiovascular System, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Isabelle Scerri
- Department of Endocrinology, Metabolism and Cardiovascular System, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Jennifer L Miles-Chan
- Department of Endocrinology, Metabolism and Cardiovascular System, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Jean-Pierre Montani
- Department of Endocrinology, Metabolism and Cardiovascular System, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Abdul G Dulloo
- Department of Endocrinology, Metabolism and Cardiovascular System, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
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29
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Angilletta MJ, Youngblood JP, Neel LK, VandenBrooks JM. The neuroscience of adaptive thermoregulation. Neurosci Lett 2019; 692:127-136. [DOI: 10.1016/j.neulet.2018.10.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/17/2018] [Accepted: 10/21/2018] [Indexed: 01/05/2023]
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30
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Kato GA, Sakamoto SH, Eto T, Okubo Y, Shinohara A, Morita T, Koshimoto C. Individual differences in torpor expression in adult mice are related to relative birth mass. ACTA ACUST UNITED AC 2018; 221:jeb.171983. [PMID: 29678821 DOI: 10.1242/jeb.171983] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 04/16/2018] [Indexed: 01/31/2023]
Abstract
Daily torpor is a physiological adaptation in small mammals and birds, characterised by drastic reductions in metabolism and body temperature. Energy-constraining conditions, such as cold and starvation, are known to cause the expression of daily torpor. However, the reason for high degrees of inter- and intra-individual variation in torpor expression (TE) in similar situations is not clear. As littermates of altricial animals are exposed to an uneven allocation of maternal resources from conception to weaning, we tested whether early nutritional experiences have long-term effects on TE in adults. We used full-sibling littermates of laboratory mice that as adults were starved overnight to induce torpor. We measured body mass from birth until adulthood as an indicator of nutritional status, and calculated the relative body mass (RBM) as an indicator of the difference in nutritional status within a litter. After maturation, we subjected mice to five repeated torpor induction trials involving 24 h of fasting and 5 days of recovery. Half of the female mice displayed great individual variation in TE whereas male mice rarely exhibited daily torpor. In females, RBM at birth influenced TE, irrespective of body mass in adulthood; thus, female mice born with low RBMs displayed high TE in adulthood. In conclusion, we provide evidence that TE in mice differs among littermates, and that this variation is linked closely to heterogeneous nutritional experiences during the fetal period.
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Affiliation(s)
- Goro A Kato
- Division of Bio-resources, Department of Biotechnology, Frontier Science Research Center, University of Miyazaki, Kihara 5200, Kiyotake, Miyazaki, Miyazaki 889-1692, Japan.,Center of Biomedical Research, Research Center for Human Disease Modeling, Graduate School of Medical Sciences, University of Kyushu, Maidashi 3-1-1, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan
| | - Shinsuke H Sakamoto
- Department of Animal and Grassland Sciences, Faculty of Agriculture, Kibana Campus, University of Miyazaki, Miyazaki 889-2192, Japan
| | - Takeshi Eto
- Center for Toki and Ecological Restoration, Niigata University, Niigata 952-0103, Japan
| | - Yoshinobu Okubo
- Japan Wildlife Research Center, 3-3-7 Kotobashi, Sumida-ku, Tokyo 130-8606, Japan
| | - Akio Shinohara
- Division of Bio-resources, Department of Biotechnology, Frontier Science Research Center, University of Miyazaki, Kihara 5200, Kiyotake, Miyazaki, Miyazaki 889-1692, Japan
| | - Tetsuo Morita
- Department of Animal and Grassland Sciences, Faculty of Agriculture, Kibana Campus, University of Miyazaki, Miyazaki 889-2192, Japan
| | - Chihiro Koshimoto
- Division of Bio-resources, Department of Biotechnology, Frontier Science Research Center, University of Miyazaki, Kihara 5200, Kiyotake, Miyazaki, Miyazaki 889-1692, Japan
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31
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Liu X, Du H, Chai Q, Jia Q, Liu L, Zhao M, Li J, Tang H, Chen W, Zhao L, Fang L, Gao L, Zhao J. Blocking mitochondrial cyclophilin D ameliorates TSH-impaired defensive barrier of artery. Redox Biol 2018; 15:418-434. [PMID: 29353219 PMCID: PMC5975066 DOI: 10.1016/j.redox.2018.01.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 01/05/2018] [Accepted: 01/07/2018] [Indexed: 12/13/2022] Open
Abstract
AIMS Endothelial cells (ECs) constitute the defensive barrier of vasculature, which maintains the vascular homeostasis. Mitochondrial oxidative stress (mitoOS) in ECs significantly affects the initiation and progression of vascular diseases. The higher serum thyroid stimulating hormone (TSH) level is being recognized as a nonconventional risk factor responsible for the increased risk of cardiovascular diseases in subclinical hypothyroidism (SCH). However, effects and underlying mechanisms of elevated TSH on ECs are still ambiguous. We sought to investigate whether cyclophilin D (CypD), emerging as a crucial mediator in mitoOS, regulates effects of TSH on ECs. METHODS AND RESULTS SCH patients with TSH > = 10mIU/L showed a positive correlation between serum TSH and endothelin-1 levels. When TSH levels declined to normal in these subjects after levothyroxine therapy, serum endothelin-1 levels were significantly reduced. Supplemented with exogenous thyroxine to keep normal thyroid hormones, thyroid-specific TSH receptor (TSHR)-knockout mice with injection of exogenous TSH exhibited elevated serum TSH levels, significant endothelial oxidative injuries and disturbed endothelium-dependent vasodilation. However, Tshr-/- mice resisted to TSH-impaired vasotonia. We further confirmed that elevated TSH triggered excessive mitochondrial permeability transition pore (mPTP) opening and mitochondrial oxidative damages in mouse aorta, as well as in cultured ECs. Genetic or pharmacological inhibition of CypD (the key regulator for mPTP opening) attenuated TSH-induced mitochondrial oxidative damages and further rescued endothelial functions. Finally, we confirmed that elevated TSH could activate CypD by enhancing CypD acetylation via inhibiting adenosine monophosphate-activated protein kinase/sirtuin-3 signaling pathway in ECs. CONCLUSIONS These findings reveal that elevated TSH triggers mitochondrial perturbations in ECs and provide insights that blocking mitochondrial CypD enhances the defensive ability of ECs under TSH exposure.
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Affiliation(s)
- Xiaojing Liu
- Deparment of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, China; Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong 250021, China; Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong 250021, China
| | - Heng Du
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX 75080, United States
| | - Qiang Chai
- Department of Cardiovascular Disease, Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan, Shandong 250001, China
| | - Qing Jia
- Department of Cardiovascular Disease, Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan, Shandong 250001, China
| | - Lu Liu
- Deparment of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, China; Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong 250021, China; Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong 250021, China
| | - Meng Zhao
- Deparment of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, China; Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong 250021, China; Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong 250021, China
| | - Jun Li
- Department of Pharmacy, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong 250021, China
| | - Hui Tang
- Department of Pharmacy, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong 250021, China
| | - Wenbin Chen
- Scientific Center, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, China
| | - Lifang Zhao
- Deparment of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, China; Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong 250021, China; Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong 250021, China
| | - Li Fang
- Deparment of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, China; Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong 250021, China; Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong 250021, China
| | - Ling Gao
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong 250021, China; Scientific Center, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, China.
| | - Jiajun Zhao
- Deparment of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, China; Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong 250021, China; Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong 250021, China.
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Involvement of orexin neurons in fasting- and central adenosine-induced hypothermia. Sci Rep 2018; 8:2717. [PMID: 29426934 PMCID: PMC5807529 DOI: 10.1038/s41598-018-21252-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 01/31/2018] [Indexed: 01/04/2023] Open
Abstract
We examined whether orexin neurons might play a protective role against fasting- and adenosine-induced hypothermia. We first measured body temperature (BT) in orexin neuron-ablated (ORX-AB) mice and wild-type (WT) controls during 24 hours of fasting. As expected, the magnitude of BT drop and the length of time suffering from hypothermia were greater in ORX-AB mice than in WT mice. Orexin neurons were active just before onset of hypothermia and during the recovery period as revealed by calcium imaging in vivo using G-CaMP. We next examined adenosine-induced hypothermia via an intracerebroventricular administration of an adenosine A1 receptor agonist, N6-cyclohexyladenosine (CHA), which induced hypothermia in both ORX-AB and WT mice. The dose of CHA required to initiate a hypothermic response in ORX-AB mice was more than 10 times larger than the dose for WT mice. Once hypothermia was established, the recovery was seemingly slower in ORX-AB mice. Activation of orexin neurons during the recovery phase was confirmed by immunohistochemistry for c-Fos. We propose that orexin neurons play dual roles (enhancer in the induction phase and compensator during the recovery phase) in adenosine-induced hypothermia and a protective/compensatory role in fasting-induced hypothermia.
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Griko Y, Regan MD. Synthetic torpor: A method for safely and practically transporting experimental animals aboard spaceflight missions to deep space. LIFE SCIENCES IN SPACE RESEARCH 2018; 16:101-107. [PMID: 29475515 DOI: 10.1016/j.lssr.2018.01.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 01/09/2018] [Accepted: 01/11/2018] [Indexed: 06/08/2023]
Abstract
Animal research aboard the Space Shuttle and International Space Station has provided vital information on the physiological, cellular, and molecular effects of spaceflight. The relevance of this information to human spaceflight is enhanced when it is coupled with information gleaned from human-based research. As NASA and other space agencies initiate plans for human exploration missions beyond low Earth orbit (LEO), incorporating animal research into these missions is vitally important to understanding the biological impacts of deep space. However, new technologies will be required to integrate experimental animals into spacecraft design and transport them beyond LEO in a safe and practical way. In this communication, we propose the use of metabolic control technologies to reversibly depress the metabolic rates of experimental animals while in transit aboard the spacecraft. Compared to holding experimental animals in active metabolic states, the advantages of artificially inducing regulated, depressed metabolic states (called synthetic torpor) include significantly reduced mass, volume, and power requirements within the spacecraft owing to reduced life support requirements, and mitigated radiation- and microgravity-induced negative health effects on the animals owing to intrinsic physiological properties of torpor. In addition to directly benefitting animal research, synthetic torpor-inducing systems will also serve as test beds for systems that may eventually hold human crewmembers in similar metabolic states on long-duration missions. The technologies for inducing synthetic torpor, which we discuss, are at relatively early stages of development, but there is ample evidence to show that this is a viable idea and one with very real benefits to spaceflight programs. The increasingly ambitious goals of world's many spaceflight programs will be most quickly and safely achieved with the help of animal research systems transported beyond LEO; synthetic torpor may enable this to be done as practically and inexpensively as possible.
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Affiliation(s)
- Yuri Griko
- NASA Ames Research Center, Moffett Field, CA 94035, United States.
| | - Matthew D Regan
- University of Wisconsin-Madison, School of Veterinary Medicine, Madison, WI 53706, United States
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Abstract
Mice subjected to cold or caloric deprivation can reduce body temperature and metabolic rate and enter a state of torpor. Here we show that administration of pyruvate, an energy-rich metabolic intermediate, can induce torpor in mice with diet-induced or genetic obesity. This is associated with marked hypothermia, decreased activity, and decreased metabolic rate. The drop in body temperature correlates with the degree of obesity and is blunted by housing mice at thermoneutrality. Induction of torpor by pyruvate in obese mice relies on adenosine signaling and is accompanied by changes in brain levels of hexose bisphosphate and GABA as detected by mass spectroscopy-based imaging. Pyruvate does not induce torpor in lean mice but results in the activation of brown adipose tissue (BAT) with an increase in the level of uncoupling protein-1 (UCP1). Denervation of BAT in lean mice blocks this increase in UCP1 and allows the pyruvate-induced torpor phenotype. Thus, pyruvate administration induces torpor in obese mice by pathways involving adenosine and GABA signaling and a failure of normal activation of BAT.
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Kato GA, Shichijo H, Takahashi T, Shinohara A, Morita T, Koshimoto C. Protein restriction does not affect body temperature pattern in female mice. Exp Anim 2017. [PMID: 28626157 PMCID: PMC5682344 DOI: 10.1538/expanim.17-0035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Daily torpor is a physiological adaptation in mammals and birds characterized by a
controlled reduction of metabolic rate and body temperature during the resting phase of
circadian rhythms. In laboratory mice, daily torpor is induced by dietary caloric
restriction. However, it is not known which nutrients are related to daily torpor
expression. To determine whether dietary protein is a key factor in inducing daily torpor
in mice, we fed mice a protein-restricted (PR) diet that included only one-quarter of the
amount of protein but the same caloric level as a control (C) diet. We assigned six
non-pregnant female ICR mice to each group and recorded their body weights and core body
temperatures for 4 weeks. Body weights in the C group increased, but those in the PR group
remained steady or decreased. Mice in both groups did not show daily torpor, but most mice
in a food-restricted group (n=6) supplied with 80% of the calories given to the C group
exhibited decreased body weights and frequently displayed daily torpor. This suggests that
protein restriction is not a trigger of daily torpor; torpid animals can conserve their
internal energy, but torpor may not play a significant role in conserving internal
protein. Thus, opportunistic daily torpor in mice may function in energy conservation
rather than protein saving.
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Affiliation(s)
- Goro A Kato
- Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, Miyazaki 889-1692, Japan.,Division of Bio-resources, Department of Biotechnology, Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, Miyazaki 889-1692, Japan.,Present address: Center of Biomedical Research, Research Center for Human Disease Modeling, Graduate School of Medical Sciences, University of Kyushu, 3-1-1 Maidashi, Fukuoka, Fukuoka 812-8582, Japan
| | - Hiroki Shichijo
- Division of Bio-resources, Department of Biotechnology, Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, Miyazaki 889-1692, Japan
| | - Toshihiro Takahashi
- Department of Animal and Grassland Sciences, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-Nishi, Miyazaki, Miyazaki 889-2192, Japan
| | - Akio Shinohara
- Division of Bio-resources, Department of Biotechnology, Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, Miyazaki 889-1692, Japan
| | - Tetsuo Morita
- Department of Animal and Grassland Sciences, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-Nishi, Miyazaki, Miyazaki 889-2192, Japan
| | - Chihiro Koshimoto
- Division of Bio-resources, Department of Biotechnology, Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, Miyazaki 889-1692, Japan
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