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Kieffer L, Sørås R, Ciesielski TM, Stawski C. Species and reproductive status influence element concentrations in bat fur. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 333:122092. [PMID: 37348695 DOI: 10.1016/j.envpol.2023.122092] [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: 03/15/2023] [Revised: 06/19/2023] [Accepted: 06/20/2023] [Indexed: 06/24/2023]
Abstract
To assess the impact of increasing pollutant levels on wildlife, we measured chemical contaminant loads in bats with different habitat and dietary preferences. Samples were taken from the fur of bats (Eptesicus nilssonii, Myotis brandtii, Myotis mystacinus and Plecotus auritus) to measure concentrations of 55 elements by inductively coupled plasma mass spectrometry (ICP-MS). Variations in element concentrations between different bat groups (species, sex, reproductive status) were analysed with a focus on arsenic (As), mercury (Hg) and lead (Pb) as these are known to cause specific health concerns in wildlife. For M. brandtii we found the highest As concentrations, especially in lactating bats, with a maximum exceeding those from other studies where bats had compromised health. Whereas for M. mystacinus there was a negative correlation between body condition index (BCI) and As concentration, indicating a potential danger for bats in the study area. In M. mystacinus and M. brandtii Hg concentrations were higher for sixteen individuals than in other studies where bats suffered genotoxic effects, although median levels were still below this threshold. Lactating bats from P. auritus and M. brandtii had higher Hg concentrations than bats of other reproductive status, which could endanger offspring as Hg can be transferred through lactation. In females from M. mystacinus Pb concentrations were more than three times higher compared to males. There was also a negative correlation between Pb concentration and BCI, which could mean that Pb has an adverse effect on health. Although many other biotic and abiotic factors should be considered, some of the variations in element concentrations could be due to different behaviours (foraging, roosting, etc.) in the studied species. The high levels of chemical contamination in some of the bats in our study, particularly reproductive individuals, is of conservation concern as bats are important agents for insect control.
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Affiliation(s)
- Luc Kieffer
- Department of Biology, Norwegian University of Science and Technology, Trondheim, NO-7491, Norway
| | - Rune Sørås
- Department of Biology, Norwegian University of Science and Technology, Trondheim, NO-7491, Norway
| | - Tomasz M Ciesielski
- Department of Biology, Norwegian University of Science and Technology, Trondheim, NO-7491, Norway; Department of Arctic Technology, The University Centre in Svalbard (UNIS), P.O. Box 156, 9171, Longyearbyen, Norway
| | - Clare Stawski
- Department of Biology, Norwegian University of Science and Technology, Trondheim, NO-7491, Norway; School of Science, Technology and Engineering, University of the Sunshine Coast, Maroochydore DC, Queensland, 4558, Australia.
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2
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Fatima I, Chen G, Botchkareva NV, Sharov AA, Thornton D, Wilkinson HN, Hardman MJ, Grutzkau A, Pedro de Magalhaes J, Seluanov A, Smith ESJ, Gorbunova V, Mardaryev AN, Faulkes CG, Botchkarev VA. Skin Aging in Long-Lived Naked Mole-Rats Is Accompanied by Increased Expression of Longevity-Associated and Tumor Suppressor Genes. J Invest Dermatol 2022; 142:2853-2863.e4. [PMID: 35691364 PMCID: PMC9613526 DOI: 10.1016/j.jid.2022.04.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 04/26/2022] [Accepted: 04/26/2022] [Indexed: 10/31/2022]
Abstract
Naked mole-rats (NMRs) (Heterocephalus glaber) are long-lived mammals that possess a natural resistance to cancer and other age-related pathologies, maintaining a healthy life span >30 years. In this study, using immunohistochemical and RNA-sequencing analyses, we compare skin morphology, cellular composition, and global transcriptome signatures between young and aged (aged 3‒4 vs. 19‒23 years, respectively) NMRs. We show that similar to aging in human skin, aging in NMRs is accompanied by a decrease in epidermal thickness; keratinocyte proliferation; and a decline in the number of Merkel cells, T cells, antigen-presenting cells, and melanocytes. Similar to that in human skin aging, expression levels of dermal collagens are decreased, whereas matrix metalloproteinase 9 and matrix metalloproteinase 11 levels increased in aged versus in young NMR skin. RNA-sequencing analyses reveal that in contrast to human or mouse skin aging, the transcript levels of several longevity-associated (Igfbp3, Igf2bp3, Ing2) and tumor-suppressor (Btg2, Cdkn1a, Cdkn2c, Dnmt3a, Hic1, Socs3, Sfrp1, Sfrp5, Thbs1, Tsc1, Zfp36) genes are increased in aged NMR skin. Overall, these data suggest that specific features in the NMR skin aging transcriptome might contribute to the resistance of NMRs to spontaneous skin carcinogenesis and provide a platform for further investigations of NMRs as a model organism for studying the biology and disease resistance of human skin.
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Affiliation(s)
- Iqra Fatima
- Centre for Skin Sciences, Faculty of Life Sciences, University of Bradford, Bradford, United Kingdom
| | - Guodong Chen
- Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Natalia V Botchkareva
- Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Andrey A Sharov
- Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Daniel Thornton
- Genomics of Aging and Rejuvenation Laboratory, Institute of Life Course and Medical Sciences, Univeristy of Liverpool, Liverpool, United Kingdom
| | - Holly N Wilkinson
- Centre for Atherothrombosis and Metabolic Disease, Hull York Medical School, University of Hull, Hull, United Kingdom
| | - Matthew J Hardman
- Centre for Atherothrombosis and Metabolic Disease, Hull York Medical School, University of Hull, Hull, United Kingdom
| | - Andreas Grutzkau
- Deutsches Rheuma-Forschungszentrum Berlin, Institute of the Leibniz Association, Berlin, Germany
| | - Joao Pedro de Magalhaes
- Genomics of Aging and Rejuvenation Laboratory, Institute of Life Course and Medical Sciences, Univeristy of Liverpool, Liverpool, United Kingdom
| | - Andrei Seluanov
- Department of Biology, School of Arts & Sciences, University of Rochester, Rochester, New York, USA; Department of Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York, USA
| | - Ewan St J Smith
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Vera Gorbunova
- Department of Biology, School of Arts & Sciences, University of Rochester, Rochester, New York, USA; Department of Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York, USA
| | - Andrei N Mardaryev
- Centre for Skin Sciences, Faculty of Life Sciences, University of Bradford, Bradford, United Kingdom
| | - Chris G Faulkes
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Vladimir A Botchkarev
- Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts, USA.
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3
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Capshaw G, Vicencio-Jimenez S, Screven LA, Burke K, Weinberg MM, Lauer AM. Physiological Evidence for Delayed Age-related Hearing Loss in Two Long-lived Rodent Species (Peromyscus leucopus and P. californicus). J Assoc Res Otolaryngol 2022; 23:617-631. [PMID: 35882705 PMCID: PMC9613845 DOI: 10.1007/s10162-022-00860-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 06/30/2022] [Indexed: 10/16/2022] Open
Abstract
Deer mice (genus Peromyscus) are an emerging model for aging studies due to their longevity relative to rodents of similar size. Although Peromyscus species are well-represented in genetic, developmental, and behavioral studies, relatively few studies have investigated auditory sensitivity in this genus. Given the potential utility of Peromyscus for investigations of age-related changes to auditory function, we recorded auditory brainstem responses (ABRs) in two Peromyscus species, P. californicus, and P. leucopus, across the lifespan. We compared hearing sensitivity and ABR wave metrics measured in these species with measurements from Mus musculus (CBA/CaJ strain) to assess age-related effects on hearing across species. Recordings in young animals showed that all species had similar hearing ranges and thresholds with peak sensitivity ranging from 8 to 16 kHz; however, P. californicus and P. leucopus were more sensitive to frequencies below 8 kHz. Although M. musculus showed significant threshold shifts across a broad range of frequencies beginning at middle age and worsening among old individuals, older Peromyscus mice retained good sensitivity to sound across their lifespan. Middle-aged P. leucopus had comparable thresholds to young for frequencies below 24 kHz. P. leucopus also had notably large ABRs that were robust to age-related amplitude reductions, although response latencies increased with age. Old P. californicus were less sensitive to mid-range tones (8-16 kHz) than young individuals; however, there were no significant age-effects on ABR amplitudes or latencies in this species. These results indicate that longevity in Peromyscus mice may be correlated with delayed aging of the auditory system and highlight these species as promising candidates for longitudinal hearing research.
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Affiliation(s)
- Grace Capshaw
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD USA
| | - Sergio Vicencio-Jimenez
- Department of Otolaryngology-HNS, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Laurel A. Screven
- Department of Otolaryngology-HNS, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Kali Burke
- Department of Otolaryngology-HNS, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Madison M. Weinberg
- Department of Otolaryngology-HNS, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Amanda M. Lauer
- Department of Otolaryngology-HNS, Johns Hopkins University School of Medicine, Baltimore, MD USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD USA
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4
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Soupé-Gilbert ME, Oedin M, Kainiu M, Girault D, Figuet O, Brescia F, Goarant C. Original Leptospira spp. in island native terrestrial mammals: a case study in Pteropus spp. bats of New Caledonia. Transbound Emerg Dis 2022; 69:e2852-e2862. [PMID: 35730517 DOI: 10.1111/tbed.14635] [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: 03/15/2022] [Revised: 05/18/2022] [Accepted: 06/17/2022] [Indexed: 11/26/2022]
Abstract
Leptospirosis is a bacterial zoonosis that occurs in tropical and subtropical regions worldwide. Chiroptera are known to be a formidable reservoir of zoonotic pathogens, including leptospires. The epidemiology of leptospirosis in bats in the Pacific Islands is poorly known, both in terms of prevalence and in terms of the bacterial strains involved. A strong host specificity between leptospiral strains and their mammalian reservoir is recognized. This phenomenon has notably been studied recently in bat communities, providing strong evidence of coevolution. In New Caledonia, a biodiversity hotspot where leptospirosis is endemic and enzootic, Chiroptera are the only indigenous terrestrial mammals. In this study, we aimed to investigate leptospires associated with three flying fox species in New Caledonia. Kidneys and urine samples of Pteropus spp. from captures and seizures were analyzed. Among 254 flying foxes analyzed, 24 harboured pathogenic leptospires corresponding to an observed prevalence of 9.45% with 15.8% on the Main Island and 4.3% on Loyalty Islands. The analysis of the rrs gene, lfb1, MLST sequences evidenced 4 distinct clusters of undescribed strains, likely corresponding to undescribed species. All four strains belong to the Group I of pathogenic Leptospira spp., which includes Leptospira interrogans, Leptospira noguchii and Leptospira kirschneri. We detected pathogenic leptospires in all 3 Pteropus spp. studied (including 2 endemic species) with no evidence of host specificity in two co-roosting species. For a better understanding of Leptospira-host coevolution, notably to genetically characterize and evaluate the virulence of these original bat-associated leptospires, it is essential to improve isolation techniques. Flying foxes are traditionally hunted and eaten in New Caledonia, a massive cause of bat-human interactions. Our results should encourage vigilance during these contacts to limit the spillover risk of these pathogens to humans. This article is protected by copyright. All rights reserved.
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Affiliation(s)
| | - Malik Oedin
- Institut Agronomique Néo-Calédonien (IAC), Equipe ARBOREAL (AgricultuRe BiOdiveRsité Et vALorisation) BP
| | - Malia Kainiu
- Institut Pasteur in New Caledonia, Leptospirosis Research and Expertise Unit
| | - Dominique Girault
- Institut Pasteur in New Caledonia, Leptospirosis Research and Expertise Unit
| | - Orane Figuet
- Institut Pasteur in New Caledonia, Leptospirosis Research and Expertise Unit
| | - Fabrice Brescia
- Institut Agronomique Néo-Calédonien (IAC), Equipe ARBOREAL (AgricultuRe BiOdiveRsité Et vALorisation) BP
| | - Cyrille Goarant
- Institut Pasteur in New Caledonia, Leptospirosis Research and Expertise Unit
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5
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1,4-dihydropyridine derivatives increase mRNA expression of Psma3, Psmb5, and Psmc6 in rats. ACTA ACUST UNITED AC 2021; 72:148-156. [PMID: 34187104 PMCID: PMC8265202 DOI: 10.2478/aiht-2021-72-3422] [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: 04/01/2020] [Accepted: 06/01/2021] [Indexed: 11/21/2022]
Abstract
The ubiquitin-proteasome system modifies different cellular and protein functions. Its dysregulation may lead to disrupted proteostasis associated with multiple pathologies and aging. Pharmacological regulation of proteasome functions is already an important part of the treatment of several diseases. 1,4-dihydropyridine (1,4-DHP) derivatives possess different pharmacological activities, including antiaging and neuroprotective. The aim of this study was to investigate the effects of several 1,4-DHP derivatives on mRNA expression levels of proteasomal genes Psma3, Psmb5, and Psmc6 in several organs of rats. Rats were treated with metcarbatone, etcarbatone, glutapyrone, styrylcarbatone, AV-153-Na, or AV-153-Ca per os for three days. mRNA expression levels were determined with real-time polymerase chain reaction (PCR). For AV-153-Na and AV-153-Ca, we also determined the expression of the Psma6 gene. In the kidney, metcarbatone, etcarbatone, styrylcarbatone, and AV-153-Na increased the expression of all analysed genes. Glutapyrone increased the expression of Psmb5 and Psmc6 but did not affect the expression of Psma3. In the blood, glutapyrone increased Psmb5 expression. In the liver, AV-153-Na increased the expression of Psma6 and Psmc6 but lowered the expression of Psmb5, while AV-153-Ca only increased Psma6 expression. The ability of 1,4-DHP derivatives to increase the expression of proteasome subunit genes might hold a therapeutic potential in conditions associated with impaired proteasomal functions, but further research is needed.
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6
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Wang X, Zhang Z, Zhang S, Yang F, Yang M, Zhou J, Hu Z, Xu X, Mao G, Chen G, Xiang W, Sun X, Xu N. Antiaging compounds from marine organisms. Food Res Int 2021; 143:110313. [DOI: 10.1016/j.foodres.2021.110313] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 03/08/2021] [Accepted: 03/10/2021] [Indexed: 02/07/2023]
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7
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Sahm A, Platzer M, Koch P, Henning Y, Bens M, Groth M, Burda H, Begall S, Ting S, Goetz M, Van Daele P, Staniszewska M, Klose JM, Costa PF, Hoffmann S, Szafranski K, Dammann P. Increased longevity due to sexual activity in mole-rats is associated with transcriptional changes in the HPA stress axis. eLife 2021; 10:57843. [PMID: 33724179 PMCID: PMC8012063 DOI: 10.7554/elife.57843] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 03/15/2021] [Indexed: 02/06/2023] Open
Abstract
Sexual activity and/or reproduction are associated with a doubling of life expectancy in the long-lived rodent genus Fukomys. To investigate the molecular mechanisms underlying this phenomenon, we analyzed 636 RNA-seq samples across 15 tissues. This analysis suggests that changes in the regulation of the hypothalamic–pituitary–adrenal stress axis play a key role regarding the extended life expectancy of reproductive vs. non-reproductive mole-rats. This is substantiated by a corpus of independent evidence. In accordance with previous studies, the up-regulation of the proteasome and so-called ‘anti-aging molecules’, for example, dehydroepiandrosterone, is linked with enhanced lifespan. On the other hand, several of our results are not consistent with knowledge about aging of short-lived model organisms. For example, we found the up-regulation of the insulin-like growth factor 1/growth hormone axis and several other anabolic processes to be compatible with a considerable lifespan prolongation. These contradictions question the extent to which findings from short-lived species can be transferred to longer-lived ones.
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Affiliation(s)
- Arne Sahm
- Computational Biology Group, Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Matthias Platzer
- Computational Biology Group, Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Philipp Koch
- Core Facility Life Science Computing, Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Yoshiyuki Henning
- Institute of Physiology, University Hospital, University of Duisburg-Essen, Essen, Germany
| | - Martin Bens
- Core Facility Sequencing, Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Marco Groth
- Core Facility Sequencing, Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Hynek Burda
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany.,Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Prague, Czech Republic
| | - Sabine Begall
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
| | - Saskia Ting
- Institute of Pathology and Neuropathology, University Hospital, University of Duisburg-Essen, Essen, Germany
| | - Moritz Goetz
- Institute of Pathology and Neuropathology, University Hospital, University of Duisburg-Essen, Essen, Germany
| | - Paul Van Daele
- Department of Zoology, University of South Bohemia, České Budějovice, Czech Republic
| | - Magdalena Staniszewska
- Department of Nuclear Medicine, University Hospital, University of Duisburg-Essen, Essen, Germany
| | - Jasmin Mona Klose
- Department of Nuclear Medicine, University Hospital, University of Duisburg-Essen, Essen, Germany
| | - Pedro Fragoso Costa
- Department of Nuclear Medicine, University Hospital, University of Duisburg-Essen, Essen, Germany
| | - Steve Hoffmann
- Computational Biology Group, Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Karol Szafranski
- Core Facility Life Science Computing, Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Philip Dammann
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany.,Central Animal Laboratory, University Hospital, University of Duisburg-Essen, Essen, Germany
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8
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Begall S, Nappe R, Hohrenk L, Schmidt TC, Burda H, Sahm A, Szafranski K, Dammann P, Henning Y. Life expectancy, family constellation and stress in giant mole-rats ( Fukomys mechowii). Philos Trans R Soc Lond B Biol Sci 2021; 376:20200207. [PMID: 33678029 DOI: 10.1098/rstb.2020.0207] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Giant mole-rats (Fukomys mechowii) are remarkably long-lived subterranean rodents (maximum recorded lifespan as reported here greater than 26 years) that live in families with one reproductive pair (breeders) and their non-reproductive offspring (non-breeders). Previous studies have shown that breeders live on average approximately twice as long as non-breeders, a finding contradicting the classic trade-off between reproduction and lifespan. Because recent evidence points to the hypothalamic-pituitary-adrenal axis as playing an important role in shaping the pace of ageing in mole-rats, we analysed the influence of the social environment of giant mole-rats on intrafamilial aggression levels, indicators of long-term stress, and, ultimately, mortality. Behavioural data indicated that family constellation, especially the presence or the absence of parents, influences agonistic behaviour. As a measure of long-term stress, we established a non-invasive method of extracting and measuring cortisol from hair of giant mole-rats. Interestingly, orphaned non-breeders exhibited significantly lower levels of cortisol and lower mortality rates than did non-breeders living with both parents. Because hypercortisolism is harmful in the long-term, intrafamilial stress could help explain the earlier onset of senescence in non-breeders, resulting in a shorter lifespan. Our findings suggest that the social environment should be considered as a further factor in ageing studies involving group-living animals. This article is part of the theme issue 'Ageing and sociality: why, when and how does sociality change ageing patterns?'
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Affiliation(s)
- S Begall
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
| | - R Nappe
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
| | - L Hohrenk
- Instrumental Analytical Chemistry and Centre for Water and Environmental Research, University of Duisburg-Essen, Essen, Germany
| | - T C Schmidt
- Instrumental Analytical Chemistry and Centre for Water and Environmental Research, University of Duisburg-Essen, Essen, Germany
| | - H Burda
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
| | - A Sahm
- Computational Biology Group, Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - K Szafranski
- Core Facility Bioinformatics, Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - P Dammann
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany.,Central Animal Laboratory, Faculty of Medicine, University of Duisburg-Essen, Essen, Germany
| | - Y Henning
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany.,Institute of Physiology, Faculty of Medicine (present address), University of Duisburg-Essen, Essen, Germany
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9
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Shields HJ, Traa A, Van Raamsdonk JM. Beneficial and Detrimental Effects of Reactive Oxygen Species on Lifespan: A Comprehensive Review of Comparative and Experimental Studies. Front Cell Dev Biol 2021; 9:628157. [PMID: 33644065 PMCID: PMC7905231 DOI: 10.3389/fcell.2021.628157] [Citation(s) in RCA: 179] [Impact Index Per Article: 59.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 01/20/2021] [Indexed: 12/15/2022] Open
Abstract
Aging is the greatest risk factor for a multitude of diseases including cardiovascular disease, neurodegeneration and cancer. Despite decades of research dedicated to understanding aging, the mechanisms underlying the aging process remain incompletely understood. The widely-accepted free radical theory of aging (FRTA) proposes that the accumulation of oxidative damage caused by reactive oxygen species (ROS) is one of the primary causes of aging. To define the relationship between ROS and aging, there have been two main approaches: comparative studies that measure outcomes related to ROS across species with different lifespans, and experimental studies that modulate ROS levels within a single species using either a genetic or pharmacologic approach. Comparative studies have shown that levels of ROS and oxidative damage are inversely correlated with lifespan. While these studies in general support the FRTA, this type of experiment can only demonstrate correlation, not causation. Experimental studies involving the manipulation of ROS levels in model organisms have generally shown that interventions that increase ROS tend to decrease lifespan, while interventions that decrease ROS tend to increase lifespan. However, there are also multiple examples in which the opposite is observed: increasing ROS levels results in extended longevity, and decreasing ROS levels results in shortened lifespan. While these studies contradict the predictions of the FRTA, these experiments have been performed in a very limited number of species, all of which have a relatively short lifespan. Overall, the data suggest that the relationship between ROS and lifespan is complex, and that ROS can have both beneficial or detrimental effects on longevity depending on the species and conditions. Accordingly, the relationship between ROS and aging is difficult to generalize across the tree of life.
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Affiliation(s)
- Hazel J Shields
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada.,Metabolic Disorders and Complications Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada.,Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Annika Traa
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada.,Metabolic Disorders and Complications Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada.,Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Jeremy M Van Raamsdonk
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada.,Metabolic Disorders and Complications Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada.,Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada.,Division of Experimental Medicine, Department of Medicine, McGill University, Montreal, QC, Canada.,Department of Genetics, Harvard Medical School, Boston, MA, United States
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10
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Abstract
For centuries, people believed that bats possessed sinister powers. Bats are thought to be ancestral hosts to many deadly viruses affecting humans including Ebola, rabies, and most recently SARS-CoV-2 coronavirus. However, bats themselves tolerate these viruses without ill effects. The second power that bats have is their longevity. Bats live much longer than similar-sized land mammals. Here we review how bats' ability to control inflammation may be contributing to their longevity. The underlying mechanisms may hold clues to developing new treatments for age-related diseases. Now may be the time to use science to exploit the secret powers of bats for human benefit.
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Affiliation(s)
- Vera Gorbunova
- Departments of Biology and Medicine, University of Rochester, Rochester, NY 14627, USA.
| | - Andrei Seluanov
- Departments of Biology and Medicine, University of Rochester, Rochester, NY 14627, USA
| | - Brian K Kennedy
- Departments of Biochemistry and Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore; Centre for Healthy Longevity, National University Health System, Singapore 117609, Singapore; Singapore Institute of Clinical Sciences, A(∗)STAR, Singapore 117609, Singapore.
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11
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A comparison of the mitochondrial proteome and lipidome in the mouse and long-lived Pipistrelle bats. Aging (Albany NY) 2020; 11:1664-1685. [PMID: 30892277 PMCID: PMC6461166 DOI: 10.18632/aging.101861] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 03/06/2019] [Indexed: 02/06/2023]
Abstract
It is accepted that smaller mammals with higher metabolic rates have shorter lifespans. The very few species that do not follow these rules can give insights into interesting differences. The recorded maximum lifespans of bats are exceptional - over 40 years, compared with the laboratory mouse of 4 years. We investigated the differences in the biochemical composition of mitochondria between bat and mouse species. We used proteomics and ultra-high-performance liquid chromatography coupled with high resolution mass spectrometry lipidomics, to interrogate mitochondrial fractions prepared from Mus musculus and Pipistrellus pipistrellus brain and skeletal muscle. Fatty acid binding protein 3 was found at different levels in mouse and bat muscle mitochondria and its orthologues were investigated in Caenorhabditis elegans knock-downs for LBP 4, 5 and 6. In the bat, high levels of free fatty acids and N-acylethanolamine lipid species together with a significantly greater abundance of fatty acid binding protein 3 in muscle (1.8-fold, p=0.037) were found. Manipulation of fatty acid binding protein orthologues in C. elegans suggest these proteins and their role in lipid regulation are important for mitochondrial function.
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12
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Lee BP, Smith M, Buffenstein R, Harries LW. Negligible senescence in naked mole rats may be a consequence of well-maintained splicing regulation. GeroScience 2020; 42:633-651. [PMID: 31927681 PMCID: PMC7205774 DOI: 10.1007/s11357-019-00150-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 12/27/2019] [Indexed: 02/07/2023] Open
Abstract
Naked mole-rats (NMRs) have amongst the longest lifespans relative to body size of any known, non-volant mammalian species. They also display an enhanced stress resistance phenotype, negligible senescence and very rarely are they burdened with chronic age-related diseases. Alternative splicing (AS) dysregulation is emerging as a potential driver of senescence and ageing. We hypothesised that the expression of splicing factors, important regulators of patterns of AS, may differ in NMRs when compared to other species with relatively shorter lifespans. We designed assays specific to NMR splicing regulatory factors and also to a panel of pre-selected brain-expressed genes known to demonstrate senescence-related alterations in AS in other species, and measured age-related changes in the transcript expression levels of these using embryonic and neonatal developmental stages through to extreme old age in NMR brain samples. We also compared splicing factor expression in both young mouse and NMR spleen and brain samples. Both NMR tissues showed approximately double the expression levels observed in tissues from similarly sized mice. Furthermore, contrary to observations in other species, following a brief period of labile expression in early life stages, adult NMR splicing factors and patterns of AS for functionally relevant brain genes remained remarkably stable for at least two decades. These findings are consistent with a model whereby the conservation of splicing regulation and stable patterns of AS may contribute to better molecular stress responses and the avoidance of senescence in NMRs, contributing to their exceptional lifespan and prolonged healthspan.
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Affiliation(s)
- B P Lee
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Barrack Road, Exeter, EX2 5DW, UK
| | - M Smith
- Calico Life Sciences LLC, 1170 Veterans Blvd., South San Francisco, CA, 94080, USA
| | - R Buffenstein
- Calico Life Sciences LLC, 1170 Veterans Blvd., South San Francisco, CA, 94080, USA.
| | - L W Harries
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Barrack Road, Exeter, EX2 5DW, UK.
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13
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Sahm A, Bens M, Henning Y, Vole C, Groth M, Schwab M, Hoffmann S, Platzer M, Szafranski K, Dammann P. Higher gene expression stability during aging in long-lived giant mole-rats than in short-lived rats. Aging (Albany NY) 2019; 10:3938-3956. [PMID: 30557854 PMCID: PMC6326690 DOI: 10.18632/aging.101683] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 11/22/2018] [Indexed: 01/07/2023]
Abstract
Many aging-associated physiological changes are known to occur in short- and long-lived species with different trajectories. Emerging evidence suggests that numerous life history trait differences between species are based on interspecies variations in gene expression. Little information is available, however, about differences in transcriptome changes during aging between mammals with diverging lifespans. For this reason, we studied the transcriptomes of five tissue types and two age cohorts of two similarly sized rodent species with very different lifespans: laboratory rats (Rattus norvegicus) and giant mole-rats (Fukomys mechowii), with maximum lifespans of 3.8 and more than 20 years, respectively. Our findings show that giant mole-rats exhibit higher gene expression stability during aging than rats. Although well-known aging signatures were detected in all tissue types of rats, they were found in only one tissue type of giant mole-rats. Furthermore, many differentially expressed genes that were found in both species were regulated in opposite directions during aging. This suggests that expression changes which cause aging in short-lived species are counteracted in long-lived species. Taken together, we conclude that expression stability in giant mole rats (and potentially in African mole-rats in general) may be one key factor for their long and healthy life.
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Affiliation(s)
- Arne Sahm
- Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Martin Bens
- Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Yoshiyuki Henning
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany.,Institute of Physiology, University of Duisburg-Essen, Essen, 45147, Germany
| | - Christiane Vole
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
| | - Marco Groth
- Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Matthias Schwab
- Department of Neurology, Jena University Hospital-Friedrich Schiller University, Jena, Germany
| | - Steve Hoffmann
- Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Matthias Platzer
- Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Karol Szafranski
- Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Philip Dammann
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany.,University Hospital, Central Animal Laboratory, University of Duisburg-Essen, Essen, Germany
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14
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Milani L, Ghiselli F. Faraway, so close. The comparative method and the potential of non-model animals in mitochondrial research. Philos Trans R Soc Lond B Biol Sci 2019; 375:20190186. [PMID: 31787048 DOI: 10.1098/rstb.2019.0186] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Inference from model organisms has been the engine for many discoveries in life science, but indiscriminate generalization leads to oversimplifications and misconceptions. Model organisms and inductive reasoning are irreplaceable: there is no other way to tackle the complexity of living systems. At the same time, it is not advisable to infer general patterns from a restricted number of species, which are very far from being representative of the diversity of life. Not all models are equal. Some organisms are suitable to find similarities across species, other highly specialized organisms can be used to focus on differences. In this opinion piece, we discuss the dominance of the mechanistic/reductionist approach in life sciences and make a case for an enhanced application of the comparative approach to study processes in all their various forms across different organisms. We also enlist some rising animal models in mitochondrial research, to exemplify how non-model organisms can be chosen in a comparative framework. These taxa often do not possess implemented tools and dedicated methods/resources. However, because of specific features, they have the potential to address still unanswered biological questions. Finally, we discuss future perspectives and caveats of the comparative method in the age of 'big data'. This article is part of the theme issue 'Linking the mitochondrial genotype to phenotype: a complex endeavour'.
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Affiliation(s)
- Liliana Milani
- Department of Biological, Geological, and Environmental Sciences, University of Bologna, Bologna, Italy
| | - Fabrizio Ghiselli
- Department of Biological, Geological, and Environmental Sciences, University of Bologna, Bologna, Italy
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15
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Jalali Z, Parvaz N. Molecular evolution of autophagy rate-limiting factor LAMP2 in placental mammals. Gene 2019; 727:144231. [PMID: 31707000 DOI: 10.1016/j.gene.2019.144231] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 10/08/2019] [Accepted: 10/27/2019] [Indexed: 01/24/2023]
Abstract
Autophagy is the cellular process of removal of misfolded or damaged macromolecules and organelles. Experimental studies have demonstrated autophagy as a major mechanism of lifespan extension in long-lived mammals such as bats and mole rat rodents. Moreover, the role of this biological process has been well documented in protection against age-associated diseases and viral infection. However, studies on the molecular adaptive changes of autophagy factors during evolution are scarce. Here, we conducted a bioinformatics study of the molecular evolution of the Lysosomal Associated Membrane Protein 2 (LAMP2), as a rate-limiting factor in the lysosomal degradation stage of autophagy (the communal step of two of autophagy types: macroautophagy and chaperone-mediated). Analyzing LAMP2 across placental mammals, our phylogenetic-based maximum likelihood analyses indicate that the majority of the coding sites undergo purifying selection. However, around 27% of sites display a relaxation of purifying constraints (average ω = 0.42128), among which, 14 particular sites undergo positive selection (ω > 1). These sites are mostly located in the first luminal domain of LAMP2 (N-domain), with a hotspot region in the 135-144 codons interval. Therefore, the N-domain may account for the functional diversity and regulation of LAMP2. In addition, the identified positive selection sites could act as key regulatory sites in the LAMP2 function. On the other hand, testing the rate of evolution in LAMP2 along different clades of placental mammals revealed a relatively relaxed evolution in LAMP2 along megabats' clade. It is not clear yet whether an expedited evolution of LAMP2 in megabats has contributed to their reported up-regulation of autophagy. Finally, our data indicate positive selection sites along the ancestral branch of the clades of rodents, mouse-related rodents, and mole-rats; and suggest the potentially important regulatory role of these sites in LAMP2. Identifying the residues under positive selection, our findings pave the way for future experimental investigations to define how these selective substitutions have functionally affected autophagy.
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Affiliation(s)
- Zahra Jalali
- Non-Communicable Diseases Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran; Department of Clinical Biochemistry, School of Medicine, Rafsanjan University of Medical Sciences, Rafsanjan, Iran.
| | - Najmeh Parvaz
- Department of Clinical Biochemistry, School of Medicine, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
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16
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Hilton HG, Rubinstein ND, Janki P, Ireland AT, Bernstein N, Fong NL, Wright KM, Smith M, Finkle D, Martin-McNulty B, Roy M, Imai DM, Jojic V, Buffenstein R. Single-cell transcriptomics of the naked mole-rat reveals unexpected features of mammalian immunity. PLoS Biol 2019; 17:e3000528. [PMID: 31751331 PMCID: PMC6894886 DOI: 10.1371/journal.pbio.3000528] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 12/05/2019] [Accepted: 11/07/2019] [Indexed: 01/08/2023] Open
Abstract
The immune system comprises a complex network of specialized cells that protects against infection, eliminates cancerous cells, and regulates tissue repair, thus serving a critical role in homeostasis, health span, and life span. The subterranean-dwelling naked mole-rat (NM-R; Heterocephalus glaber) exhibits prolonged life span relative to its body size, is unusually cancer resistant, and manifests few physiological or molecular changes with advancing age. We therefore hypothesized that the immune system of NM-Rs evolved unique features that confer enhanced cancer immunosurveillance and prevent the age-associated decline in homeostasis. Using single-cell RNA-sequencing (scRNA-seq) we mapped the immune system of the NM-R and compared it to that of the short-lived, cancer-prone mouse. In contrast to the mouse, we find that the NM-R immune system is characterized by a high myeloid-to-lymphoid cell ratio that includes a novel, lipopolysaccharide (LPS)-responsive, granulocyte cell subset. Surprisingly, we also find that NM-Rs lack canonical natural killer (NK) cells. Our comparative genomics analyses support this finding, showing that the NM-R genome lacks an expanded gene family that controls NK cell function in several other species. Furthermore, we reconstructed the evolutionary history that likely led to this genomic state. The NM-R thus challenges our current understanding of mammalian immunity, favoring an atypical, myeloid-biased mode of innate immunosurveillance, which may contribute to its remarkable health span.
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Affiliation(s)
- Hugo G. Hilton
- Calico Life Sciences LLC, South San Francisco, California, United States of America
| | - Nimrod D. Rubinstein
- Calico Life Sciences LLC, South San Francisco, California, United States of America
| | - Peter Janki
- Calico Life Sciences LLC, South San Francisco, California, United States of America
| | - Andrea T. Ireland
- Calico Life Sciences LLC, South San Francisco, California, United States of America
| | - Nicholas Bernstein
- Calico Life Sciences LLC, South San Francisco, California, United States of America
| | - Nicole L. Fong
- Calico Life Sciences LLC, South San Francisco, California, United States of America
| | - Kevin M. Wright
- Calico Life Sciences LLC, South San Francisco, California, United States of America
| | - Megan Smith
- Calico Life Sciences LLC, South San Francisco, California, United States of America
| | - David Finkle
- Calico Life Sciences LLC, South San Francisco, California, United States of America
| | - Baby Martin-McNulty
- Calico Life Sciences LLC, South San Francisco, California, United States of America
| | - Margaret Roy
- Calico Life Sciences LLC, South San Francisco, California, United States of America
| | - Denise M. Imai
- Comparative Pathology Laboratory, School of Veterinary Medicine, University of California, Davis, Davis, California, United States of America
| | - Vladimir Jojic
- Calico Life Sciences LLC, South San Francisco, California, United States of America
| | - Rochelle Buffenstein
- Calico Life Sciences LLC, South San Francisco, California, United States of America
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17
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Adwan Shekhidem H, Sharvit L, Leman E, Manov I, Roichman A, Holtze S, M Huffman D, Y Cohen H, Bernd Hildebrandt T, Shams I, Atzmon G. Telomeres and Longevity: A Cause or an Effect? Int J Mol Sci 2019; 20:ijms20133233. [PMID: 31266154 PMCID: PMC6651551 DOI: 10.3390/ijms20133233] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 06/25/2019] [Accepted: 06/29/2019] [Indexed: 01/20/2023] Open
Abstract
Telomere dynamics have been found to be better predictors of survival and mortality than chronological age. Telomeres, the caps that protect the end of linear chromosomes, are known to shorten with age, inducing cell senescence and aging. Furthermore, differences in age-related telomere attrition were established between short-lived and long-lived organisms. However, whether telomere length is a “biological thermometer” that reflects the biological state at a certain point in life or a biomarker that can influence biological conditions, delay senescence and promote longevity is still an ongoing debate. We cross-sectionally tested telomere length in different tissues of two long-lived (naked mole-rat and Spalax) and two short-lived (rat and mice) species to tease out this enigma. While blood telomere length of the naked mole-rat (NMR) did not shorten with age but rather showed a mild elongation, telomere length in three tissues tested in the Spalax declined with age, just like in short-lived rodents. These findings in the NMR, suggest an age buffering mechanism, while in Spalax tissues the shortening of the telomeres are in spite of its extreme longevity traits. Therefore, using long-lived species as models for understanding the role of telomeres in longevity is of great importance since they may encompass mechanisms that postpone aging.
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Affiliation(s)
| | - Lital Sharvit
- Department of Human Biology, University of Haifa, Haifa 3498838, Israel
| | - Eva Leman
- Institute of Evolution and Department of Evolutionary and Environmental Biology, University of Haifa, Haifa 3498838, Israel
| | - Irena Manov
- Institute of Evolution and Department of Evolutionary and Environmental Biology, University of Haifa, Haifa 3498838, Israel
| | - Asael Roichman
- Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Susanne Holtze
- Leibniz Institute for Zoo and Wildlife Research, D-10315 Berlin, Germany
| | - Derek M Huffman
- Departments of Molecular Pharmacology, Medicine, and the Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Haim Y Cohen
- Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Thomas Bernd Hildebrandt
- Leibniz Institute for Zoo and Wildlife Research, D-10315 Berlin, Germany
- Freie Universität Berlin, D-14195 Berlin, Germany
| | - Imad Shams
- Institute of Evolution and Department of Evolutionary and Environmental Biology, University of Haifa, Haifa 3498838, Israel
| | - Gil Atzmon
- Department of Human Biology, University of Haifa, Haifa 3498838, Israel.
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18
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Munro D, Baldy C, Pamenter ME, Treberg JR. The exceptional longevity of the naked mole-rat may be explained by mitochondrial antioxidant defenses. Aging Cell 2019; 18:e12916. [PMID: 30768748 PMCID: PMC6516170 DOI: 10.1111/acel.12916] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 10/31/2018] [Accepted: 12/30/2018] [Indexed: 12/21/2022] Open
Abstract
Naked mole-rats (NMRs) are mouse-sized mammals that exhibit an exceptionally long lifespan (>30 vs. <4 years for mice), and resist aging-related pathologies such as cardiovascular and pulmonary diseases, cancer, and neurodegeneration. However, the mechanisms underlying this exceptional longevity and disease resistance remain poorly understood. The oxidative stress theory of aging posits that (a) senescence results from the accumulation of oxidative damage inflicted by reactive oxygen species (ROS) of mitochondrial origin, and (b) mitochondria of long-lived species produce less ROS than do mitochondria of short-lived species. However, comparative studies over the past 28 years have produced equivocal results supporting this latter prediction. We hypothesized that, rather than differences in ROS generation, the capacity of mitochondria to consume ROS might distinguish long-lived species from short-lived species. To test this hypothesis, we compared mitochondrial production and consumption of hydrogen peroxide (H2 O2 ; as a proxy of overall ROS metabolism) between NMR and mouse skeletal muscle and heart. We found that the two species had comparable rates of mitochondrial H2 O2 generation in both tissues; however, the capacity of mitochondria to consume ROS was markedly greater in NMRs. Specifically, maximal observed consumption rates were approximately two and fivefold greater in NMRs than in mice, for skeletal muscle and heart, respectively. Our results indicate that differences in matrix ROS detoxification capacity between species may contribute to their divergence in lifespan.
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Affiliation(s)
- Daniel Munro
- Department of Biological SciencesUniversity of ManitobaWinnipegManitobaCanada
- Department of BiologyUniversity of OttawaOttawaOntarioCanada
- Centre on AgingUniversity of ManitobaWinnipegManitobaCanada
| | - Cécile Baldy
- Department of BiologyUniversity of OttawaOttawaOntarioCanada
| | - Matthew E. Pamenter
- Department of BiologyUniversity of OttawaOttawaOntarioCanada
- University of Ottawa Brain and Mind Research InstituteOttawaOntarioCanada
| | - Jason R. Treberg
- Department of Biological SciencesUniversity of ManitobaWinnipegManitobaCanada
- Centre on AgingUniversity of ManitobaWinnipegManitobaCanada
- Department of food and Human Nutritional SciencesUniversity of ManitobaWinnipegManitobaCanada
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Abstract
Thyroid function is most often monitored clinically through measurement of the regulatory hormone, thyrotropin (TSH). Subclinical hypothyroidism is generally defined as a TSH level above the reference range while thyroid hormone levels remain within the reference range. Elevated TSH is more common among older adults, leading to high rates of treatment, and over-treatment, in this population. However, the use of levothyroxine in older adults with mild TSH elevations has begun to be called into question by observations that demonstrate a lack of harm from not treating and a lack of benefit from treating. Importantly, these findings suggest that the existing diagnostic algorithm for subclinical hypothyroidism, based on isolated TSH elevation, may be inappropriate for older adults. Age-specific reference ranges have been suggested as a way to avoid inappropriate treatment, but that strategy continues to rely on population norms rather than disease definitions to drive clinical decisions. Recent insight into age-related variability in the underlying pathophysiology that impacts on thyroid function tests demonstrates the need for new clinical tools to allow the targeted use of therapy where it will have benefit.
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Affiliation(s)
- Jennifer S Mammen
- Johns Hopkins School of Medicine, Department of Medicine, Division of Endocrinology, Diabetes and Metabolism
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20
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Wallis M. Molecular evolution of prolactin in Chiroptera: Accelerated evolution and a large insertion in vespertilionid bats. Gen Comp Endocrinol 2018; 269:102-111. [PMID: 30172709 DOI: 10.1016/j.ygcen.2018.08.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 08/27/2018] [Accepted: 08/29/2018] [Indexed: 11/15/2022]
Abstract
Pituitary prolactin (PRL) shows an episodic pattern of evolution in mammals, with a slow underlying rate (near stasis) and periods of rapid change in some groups. PRL evolution in bats, the second most speciose mammalian order, has not previously been studied, and is examined here. Slow basal evolution of PRL is seen in some bats, particularly megabats, but in most microbat groups evolution of PRL is more rapid. Accelerated evolution of PRL is particularly notable in the family Vespertilionidae, where analysis of nonsynonymous and synonymous substitutions indicates that it reflects adaptive evolution/positive selection. Remarkably, vespertilionid bats also show a large sequence insertion, of variable length, into exon 4 of PRL, giving a protein sequence 18-60 amino acids longer than normal, with the longest insertions in bats of the genus Myotis. An equivalent insertion has not been reported in PRL of any other vertebrate group. In the 3-dimensional structure of the complex between PRL and the extracellular domain (ecd) of its receptor (PRL:PRLR2) the inserted sequence is seen to be introduced in the short loop between helices 2 and 3 of PRL; it is far removed from the receptor-binding sites, and may not interfere with binding. The ecd of the receptor also shows variable rates of evolution, with a higher rate in the Vespertilionidae, but this is much less marked than for the hormone. The distribution of substitutions introduced into PRL during vespertilionid evolution appears to be non-random, and this and the evidence for positive selection suggests that the rapid evolution and insert sequence introduction were associated with a significant change in the biological properties of the hormone.
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Affiliation(s)
- Michael Wallis
- Biochemistry and Biomedicine Group, School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK.
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21
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Göring H. Vitamin D in Nature: A Product of Synthesis and/or Degradation of Cell Membrane Components. BIOCHEMISTRY (MOSCOW) 2018; 83:1350-1357. [DOI: 10.1134/s0006297918110056] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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