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Song J, Xiao L, Zhang Z, Wang Y, Kouis P, Rasmussen LJ, Dai F. Effects of reactive oxygen species and mitochondrial dysfunction on reproductive aging. Front Cell Dev Biol 2024; 12:1347286. [PMID: 38465288 PMCID: PMC10920300 DOI: 10.3389/fcell.2024.1347286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 02/12/2024] [Indexed: 03/12/2024] Open
Abstract
Mitochondria, the versatile organelles crucial for cellular and organismal viability, play a pivotal role in meeting the energy requirements of cells through the respiratory chain located in the inner mitochondrial membrane, concomitant with the generation of reactive oxygen species (ROS). A wealth of evidence derived from contemporary investigations on reproductive longevity strongly indicates that the aberrant elevation of ROS level constitutes a fundamental factor in hastening the aging process of reproductive systems which are responsible for transmission of DNA to future generations. Constant changes in redox status, with a pro-oxidant shift mainly through the mitochondrial generation of ROS, are linked to the modulation of physiological and pathological pathways in gametes and reproductive tissues. Furthermore, the quantity and quality of mitochondria essential to capacitation and fertilization are increasingly associated with reproductive aging. The article aims to provide current understanding of the contributions of ROS derived from mitochondrial respiration to the process of reproductive aging. Moreover, understanding the impact of mitochondrial dysfunction on both female and male fertility is conducive to finding therapeutic strategies to slow, prevent or reverse the process of gamete aging, and thereby increase reproductive longevity.
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Affiliation(s)
- Jiangbo Song
- State Key Laboratory of Resource Insects, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
| | - Li Xiao
- State Key Laboratory of Resource Insects, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
| | - Zhehao Zhang
- State Key Laboratory of Resource Insects, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
| | - Yujin Wang
- State Key Laboratory of Resource Insects, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
| | - Panayiotis Kouis
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Lene Juel Rasmussen
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Fangyin Dai
- State Key Laboratory of Resource Insects, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
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Hatle JD, Maslikova V, Short CA, Bracey D, Darmanjian M, Morningstar S, Reams B, Mashanov VS, Jahan-Mihan A, Hahn DA. Protein storage and reproduction increase in grasshoppers on a diet matched to the amino acids of egg yolk protein. J Exp Biol 2022; 225:jeb244450. [PMID: 35916173 PMCID: PMC9482367 DOI: 10.1242/jeb.244450] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 07/21/2022] [Indexed: 11/20/2022]
Abstract
The diets of animals are essential to support development, and protein is key. Accumulation of stored nutrients can support developmental events such as molting and initiation of reproduction. Agricultural studies have addressed how dietary protein quality affects growth, but few studies have addressed the effects of dietary protein quality on developmental transitions. Studies on how dietary quality may affect protein storage and development are possible in arthropods, which store proteins in the hemolymph. We hypothesized that diets with a composition of amino acids that matches the precursor of egg yolk protein (vitellogenin, Vg) will be high quality and support both egg production and accumulation of storage proteins. Grasshoppers were fed one of two isonitrogenous solutions of amino acids daily: Vg-balanced (matched to Vg) or Unbalanced (same total moles of amino acids, but not matched to egg yolk). We measured reproduction and storage protein levels in serial hemolymph samples from individuals. The Vg-balanced group had greater reproduction and greater cumulative levels of storage proteins than did the Unbalanced group. This occurred even though amino acids fed to the Vg-balanced group were not a better match to storage protein than were the amino acids fed to the Unbalanced group. Further, oviposition timing was best explained by a combination of diet, age at the maximum level of storage protein hexamerin-270 and accumulation of hexamerin-90. Our study tightens the link between storage proteins and commitment to reproduction, and shows that dietary protein quality is vital for protein storage and reproduction.
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Affiliation(s)
- John D. Hatle
- Department of Biology, 1 UNF Drive, Jacksonville, FL 32224, USA
| | | | - Clancy A. Short
- Entomology and Nematology Department, University of Florida, Institute of Food and Agricultural Sciences, 1881 Natural Area Drive, Steinmetz Hall, Gainesville, FL 32611, USA
| | - Donald Bracey
- Entomology and Nematology Department, University of Florida, Institute of Food and Agricultural Sciences, 1881 Natural Area Drive, Steinmetz Hall, Gainesville, FL 32611, USA
| | | | | | - Brooke Reams
- Department of Biology, 1 UNF Drive, Jacksonville, FL 32224, USA
| | | | | | - Daniel A. Hahn
- Entomology and Nematology Department, University of Florida, Institute of Food and Agricultural Sciences, 1881 Natural Area Drive, Steinmetz Hall, Gainesville, FL 32611, USA
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3
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Promislow DEL, Flatt T, Bonduriansky R. The Biology of Aging in Insects: From Drosophila to Other Insects and Back. ANNUAL REVIEW OF ENTOMOLOGY 2022; 67:83-103. [PMID: 34590891 PMCID: PMC8940561 DOI: 10.1146/annurev-ento-061621-064341] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
An enormous amount of work has been done on aging in Drosophila melanogaster, a classical genetic and molecular model system, but also in numerous other insects. However, these two extensive bodies of work remain poorly integrated to date. Studies in Drosophila often explore genetic, developmental, physiological, and nutrition-related aspects of aging in the lab, while studies in other insects often explore ecological, social, and somatic aspects of aging in both lab and natural populations. Alongside exciting genomic and molecular research advances in aging in Drosophila, many new studies have also been published on aging in various other insects, including studies on aging in natural populations of diverse species. However, no broad synthesis of these largely separate bodies of work has been attempted. In this review, we endeavor to synthesize these two semi-independent literatures to facilitate collaboration and foster the exchange of ideas and research tools. While lab studies of Drosophila have illuminated many fundamental aspects of senescence, the stunning diversity of aging patterns among insects, especially in the context of their rich ecology, remains vastlyunderstudied. Coupled with field studies and novel, more easily applicable molecular methods, this represents a major opportunity for deepening our understanding of the biology of aging in insects and beyond.
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Affiliation(s)
- Daniel E L Promislow
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington 98195, USA;
- Department of Biology, University of Washington, Seattle, Washington 98195, USA
| | - Thomas Flatt
- Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland;
| | - Russell Bonduriansky
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales Sydney, New South Wales 2052, Australia;
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Gems D, Kern CC, Nour J, Ezcurra M. Reproductive Suicide: Similar Mechanisms of Aging in C. elegans and Pacific Salmon. Front Cell Dev Biol 2021; 9:688788. [PMID: 34513830 PMCID: PMC8430333 DOI: 10.3389/fcell.2021.688788] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 07/21/2021] [Indexed: 12/17/2022] Open
Abstract
In some species of salmon, reproductive maturity triggers the development of massive pathology resulting from reproductive effort, leading to rapid post-reproductive death. Such reproductive death, which occurs in many semelparous organisms (with a single bout of reproduction), can be prevented by blocking reproductive maturation, and this can increase lifespan dramatically. Reproductive death is often viewed as distinct from senescence in iteroparous organisms (with multiple bouts of reproduction) such as humans. Here we review the evidence that reproductive death occurs in C. elegans and discuss what this means for its use as a model organism to study aging. Inhibiting insulin/IGF-1 signaling and germline removal suppresses reproductive death and greatly extends lifespan in C. elegans, but can also extend lifespan to a small extent in iteroparous organisms. We argue that mechanisms of senescence operative in reproductive death exist in a less catastrophic form in iteroparous organisms, particularly those that involve costly resource reallocation, and exhibit endocrine-regulated plasticity. Thus, mechanisms of senescence in semelparous organisms (including plants) and iteroparous ones form an etiological continuum. Therefore understanding mechanisms of reproductive death in C. elegans can teach us about some mechanisms of senescence that are operative in iteroparous organisms.
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Affiliation(s)
- David Gems
- Institute of Healthy Ageing, Research Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
| | - Carina C. Kern
- Institute of Healthy Ageing, Research Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
| | - Joseph Nour
- Institute of Healthy Ageing, Research Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
| | - Marina Ezcurra
- School of Biosciences, University of Kent, Canterbury, United Kingdom
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McCracken AW, Adams G, Hartshorne L, Tatar M, Simons MJP. The hidden costs of dietary restriction: Implications for its evolutionary and mechanistic origins. SCIENCE ADVANCES 2020; 6:eaay3047. [PMID: 32128403 PMCID: PMC7034997 DOI: 10.1126/sciadv.aay3047] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 12/04/2019] [Indexed: 05/14/2023]
Abstract
Dietary restriction (DR) extends life span across taxa. Despite considerable research, universal mechanisms of DR have not been identified, limiting its translational potential. Guided by the conviction that DR evolved as an adaptive, pro-longevity physiological response to food scarcity, biomedical science has interpreted DR as an activator of pro-longevity molecular pathways. Current evolutionary theory predicts that organisms invest in their soma during DR, and thus when resource availability improves, should outcompete rich-fed controls in survival and/or reproduction. Testing this prediction in Drosophila melanogaster (N > 66,000 across 11 genotypes), our experiments revealed substantial, unexpected mortality costs when flies returned to a rich diet following DR. The physiological effects of DR should therefore not be interpreted as intrinsically pro-longevity, acting via somatic maintenance. We suggest DR could alternatively be considered an escape from costs incurred under nutrient-rich conditions, in addition to costs associated with DR.
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Affiliation(s)
- Andrew W. McCracken
- Department of Animal and Plant Sciences and Bateson Centre, The University of Sheffield, Sheffield S10 2TN, UK
| | - Gracie Adams
- Department of Animal and Plant Sciences and Bateson Centre, The University of Sheffield, Sheffield S10 2TN, UK
| | - Laura Hartshorne
- Department of Animal and Plant Sciences and Bateson Centre, The University of Sheffield, Sheffield S10 2TN, UK
| | - Marc Tatar
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, USA
| | - Mirre J. P. Simons
- Department of Animal and Plant Sciences and Bateson Centre, The University of Sheffield, Sheffield S10 2TN, UK
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Hatle JD, Karjasevic A, Rehfeldt E, Nagle FS, Milano LJ, Patel S, Hiatt D, McCue MD. Life-extending dietary restriction, but not dietary supplementation of branched-chain amino acids, can increase organismal oxidation rates of individual branched-chain amino acids by grasshoppers. ACTA ACUST UNITED AC 2019; 5:209-223. [PMID: 31984246 PMCID: PMC6971830 DOI: 10.3233/nha-190073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND: Life-extending dietary restriction increases energy demands. Branched-chain amino acids (BCAAs), at high levels, may be detrimental to healthspan by activating the mechanistic Target of Rapamycin (mTOR). Whether organismal oxidation of BCAAs increases upon dietary restriction is unknown. OBJECTIVE: Test whether dietary restriction (DR, which creates an energy deficit) or supplemental dietary BCAAs (superfluous BCAAs) increases oxidation of BCAAs, potentially reducing their levels to improve healthspan. METHODS: Grasshoppers were reared to middle-age on one of four diets, each a level of lettuce feeding and a force-fed solution: 1) ad libitum lettuce & buffer, 2) ad libitum lettuce & supplemental BCAAs, 3) DR lettuce & buffer, and 4) DR lettuce & supplemental BCAAs. On trial days, grasshoppers were force-fed one 13C-1-BCAA (isoleucine, leucine, or valine). Breath was collected and tested for 13CO2, which represents organismal oxidation of the amino acid. Additional trials re-tested oxidation of leucine (the most potent activator of mTOR) in both females and males on dietary restriction. RESULTS: Dietary restriction generally increased cumulative oxidation of each BCAA in females and hungry males over ∼8 hr. Results were consistent for isoleucine and valine, but less so for leucine. Supplementation of BCAAs, in combination with dietary restriction, increased isoleucine in hemolymph, with similar trends for leucine and valine. Despite this, supplementation of BCAAs did not alter oxidation of any BCAAs. CONCLUSIONS: Dietary restriction can increase oxidation of BCAAs, likely due to an energy deficit. The increased oxidation may decrease available BCAAs for activation of mTOR and improve healthspan.
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Affiliation(s)
- J D Hatle
- Department of Biology, University of North Florida, Jacksonville, FL, USA
| | - A Karjasevic
- Department of Biology, University of North Florida, Jacksonville, FL, USA
| | - E Rehfeldt
- Department of Biology, University of North Florida, Jacksonville, FL, USA
| | - F S Nagle
- Department of Biology, University of North Florida, Jacksonville, FL, USA
| | - L J Milano
- Department of Biology, University of North Florida, Jacksonville, FL, USA
| | - S Patel
- Department of Biology, University of North Florida, Jacksonville, FL, USA
| | - D Hiatt
- Department of Biology, University of North Florida, Jacksonville, FL, USA
| | - M D McCue
- Sable Systems International, North Las Vegas, NV, USA
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Heck MJ, Hatle JD. Interaction of neuropeptide F and diet levels effects carbonyl levels in grasshoppers. Exp Gerontol 2018; 113:186-192. [PMID: 30316813 PMCID: PMC6233717 DOI: 10.1016/j.exger.2018.09.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 09/16/2018] [Accepted: 09/30/2018] [Indexed: 10/28/2022]
Affiliation(s)
- Matthew J Heck
- University of North Florida, Dept of Biology, Jacksonville, FL 32224, USA
| | - John D Hatle
- University of North Florida, Dept of Biology, Jacksonville, FL 32224, USA.
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8
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Rosenblatt AE. Shifts in plant nutrient content in combined warming and drought scenarios may alter reproductive fitness across trophic levels. OIKOS 2018. [DOI: 10.1111/oik.05272] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Adam E. Rosenblatt
- College of Arts and Sciences, Univ. of North Florida; 1 UNF Drive Jacksonville FL 32245-6761 USA
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9
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Hatle JD, Awan A, Nicholas J, Koch R, Vokrri JR, McCue MD, Williams CM, Davidowitz G, Hahn DA. Life-extending dietary restriction and ovariectomy each increase leucine oxidation and alter leucine allocation in grasshoppers. Exp Gerontol 2017; 96:155-161. [PMID: 28668481 DOI: 10.1016/j.exger.2017.06.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 06/14/2017] [Accepted: 06/27/2017] [Indexed: 10/19/2022]
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Heck MJ, Pehlivanovic M, Purcell JU, Hahn DA, Hatle JD. Life-extending Dietary Restriction Reduces Oxidative Damage of Proteins in Grasshoppers but Does Not Alter Allocation of Ingested Nitrogen to Somatic Tissues. J Gerontol A Biol Sci Med Sci 2017; 72:616-623. [PMID: 27307298 DOI: 10.1093/gerona/glw094] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 05/04/2016] [Indexed: 11/13/2022] Open
Abstract
Dietary restriction (DR) extends life span and reduces reproduction in most animals. The disposable soma hypothesis suggests that this longevity is the result of reduced investment in reproduction and increased nutrient allocation to the soma, permitting an increase in cellular maintenance. To investigate the role of nutrient allocation upon life-extending DR, tissue-specific nitrogen allocation was tracked in grasshoppers (Romalea microptera) upon a full or restricted (60% of full) diet. In addition, carbonyl (oxidized protein) assays addressed tissue maintenance. To develop a labeled diet on which grasshoppers could thrive, hydroponically grown Romaine lettuce was enriched with 15N. This allowed quantification of nitrogen allocation upon a normal or restricted diet. There was a 50% decrease in reproductive investment upon DR. At the same time, relative allocation of 15N to the ovary did not change. Most important, relative allocation was similar between restricted and full diet grasshoppers for somatic tissues (ie, mandibular and femur muscle, dried hemolymph, gut, and fat body). Carbonyl assays of muscles, hemolymph, and gut revealed an overall reduction in protein oxidation upon DR. These data suggest that DR does not alter nutrient allocation but does reduce protein oxidation, an observation that is inconsistent with the basic predictions of the disposable soma hypothesis.
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Affiliation(s)
- Matthew J Heck
- Department of Biology, University of North Florida, Jacksonville
| | - Mirna Pehlivanovic
- Department of Biology, University of North Florida, Jacksonville
- Present address: Stony Brook University, New York
| | - Jennifer U Purcell
- Department of Biology, University of North Florida, Jacksonville
- Present address: Lake Erie College of Medicine, Florida, Pennsylvania
| | - Daniel A Hahn
- Department of Entomology, University of Florida, Gainesville
| | - John D Hatle
- Department of Biology, University of North Florida, Jacksonville
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11
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Faiman R, Solon-Biet S, Sullivan M, Huestis DL, Lehmann T. The contribution of dietary restriction to extended longevity in the malaria vector Anopheles coluzzii. Parasit Vectors 2017; 10:156. [PMID: 28340627 PMCID: PMC5366120 DOI: 10.1186/s13071-017-2088-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 03/14/2017] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Variation in longevity has long been of interest in vector biology because of its implication in disease transmission through vectorial capacity. Recent studies suggest that Anopheles coluzzii adults persist during the ~7 month dry season via aestivation. Recently there has been a growing body of evidence linking dietary restriction and low ratio of dietary protein to carbohydrate with extended longevity of animals. Here, we evaluated the effects of dietary restriction and the protein : carbohydrate ratio on longevity of An. coluzzii. RESULTS In our experiment, we combined dietary regimes with temperature and relative humidity to assess their effects on An. coluzzii longevity, in an attempt to simulate aestivation under laboratory conditions. Our results showed significant effects of both the physical and the dietary variables on longevity, but that diet regimen had a considerably greater effect than those of the physical conditions. Higher temperature and lower humidity reduced longevity. At 22 °C dietary protein (blood) shortened longevity when sugar was not restricted (RH = 85%), but extended longevity when sugar was restricted (RH = 50%). CONCLUSIONS Dietary restriction extended longevity in accord with predictions, but protein : carbohydrate ratio had a negligible effect. We identified conditions that significantly extend longevity in malaria vectors, however, the extent of increase in longevity was insufficient to simulate aestivation.
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Affiliation(s)
- Roy Faiman
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, MD, 20852, USA.
| | | | - Margery Sullivan
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, MD, 20852, USA
| | - Diana L Huestis
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, MD, 20852, USA.,Office of Global Health Diplomacy, U.S. Department of State, 1800 G Street NW, Suite 10300, Washington, DC, 20006, USA
| | - Tovi Lehmann
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, MD, 20852, USA
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12
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Pu YZ, Wan QL, Ding AJ, Luo HR, Wu GS. Quantitative proteomics analysis of Caenorhabditis elegans upon germ cell loss. J Proteomics 2017; 156:85-93. [DOI: 10.1016/j.jprot.2017.01.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 01/14/2017] [Accepted: 01/19/2017] [Indexed: 10/20/2022]
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Vitellogenin-RNAi and ovariectomy each increase lifespan, increase protein storage, and decrease feeding, but are not additive in grasshoppers. Biogerontology 2015; 16:761-74. [PMID: 26298568 DOI: 10.1007/s10522-015-9599-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 08/12/2015] [Indexed: 01/29/2023]
Abstract
Reduced reproduction has been shown to increase lifespan in many animals, yet the mechanisms behind this trade-off are unclear. We addressed this question by combining two distinct, direct means of life-extension via reduced reproduction, to test whether they were additive. In the lubber grasshopper, Romalea microptera, ovariectomized (OVX) individuals had a ~20% increase in lifespan and a doubling of storage relative to controls (Sham operated). Similarly, young female grasshoppers treated with RNAi against vitellogenin (the precursor to egg yolk protein) had increased fat body mass and halted ovarian growth. In this study, we compared VgRNAi to two control groups that do not reduce reproduction, namely buffer injection (Buffer) and injection with RNAi against a hexameric storage protein (Hex90RNAi). Each injection treatment was tested with and without ovariectomy. Hence, we tested feeding, storage, and lifespans in six groups: OVX and Buffer, OVX and Hex90RNAi, OVX and VgRNAi, Sham and Buffer, Sham and Hex90RNAi, and Sham and VgRNAi. Ovariectomized grasshoppers and VgRNAi grasshoppers each had similar reductions in feeding (~40%), increases in protein storage in the hemolymph (150-300%), and extensions in lifespan (13-21%). Ovariectomized grasshoppers had higher vitellogenin protein levels than did VgRNAi grasshoppers. Last but not least, when ovariectomy and VgRNAi were applied together, there was no greater effect on feeding, protein storage, or longevity. Hence, feeding regulation, and protein storage in insects, may be conserved components of life-extension via reduced reproduction.
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15
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Germline signals deploy NHR-49 to modulate fatty-acid β-oxidation and desaturation in somatic tissues of C. elegans. PLoS Genet 2014; 10:e1004829. [PMID: 25474470 PMCID: PMC4256272 DOI: 10.1371/journal.pgen.1004829] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 10/15/2014] [Indexed: 11/19/2022] Open
Abstract
In C. elegans, removal of the germline extends lifespan significantly. We demonstrate that the nuclear hormone receptor, NHR-49, enables the response to this physiological change by increasing the expression of genes involved in mitochondrial β-oxidation and fatty-acid desaturation. The coordinated augmentation of these processes is critical for germline-less animals to maintain their lipid stores and to sustain de novo fat synthesis during adulthood. Following germline ablation, NHR-49 is up-regulated in somatic cells by the conserved longevity determinants DAF-16/FOXO and TCER-1/TCERG1. Accordingly, NHR-49 overexpression in fertile animals extends their lifespan modestly. In fertile adults, nhr-49 expression is DAF-16/FOXO and TCER-1/TCERG1 independent although its depletion causes age-related lipid abnormalities. Our data provide molecular insights into how reproductive stimuli are integrated into global metabolic changes to alter the lifespan of the animal. They suggest that NHR-49 may facilitate the adaptation to loss of reproductive potential through synchronized enhancement of fatty-acid oxidation and desaturation, thus breaking down some fats ordained for reproduction and orchestrating a lipid profile conducive for somatic maintenance and longevity. Much is known about how increasing age impairs fertility but we know little about how reproduction influences rate of aging in animals. Studies in model organisms such as worms and flies have begun to shed light on this relationship. In worms, removing germ cells that give rise to sperm and oocytes extends lifespan, increases endurance and elevates fat. Fat metabolism and hormonal signals play major roles in this lifespan augmentation but the genetic mechanisms involved are poorly understood. We show that a gene, nhr-49, enhances worm lifespan following germ-cell removal. NHR-49 is increased in animals that lack germ cells by conserved longevity proteins, DAF-16 and TCER-1. NHR-49, in turn, increases levels of genes that help burn fat and convert saturated fats into unsaturated forms. Through synchronized enhancement of these processes, NHR-49 helps eliminate excess fat delegated for reproduction and converts lipids into forms that favor a long life. NHR-49 impacts these processes during aging in normal animals too, but using different regulatory mechanisms. Our data helps understand how normal lipid metabolic processes can be harnessed to adapt to physiological fluctuations brought on by changes in the reproductive status of animals.
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16
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Tokar DR, Veleta KA, Canzano J, Hahn DA, Hatle JD. Vitellogenin RNAi halts ovarian growth and diverts reproductive proteins and lipids in young grasshoppers. Integr Comp Biol 2014; 54:931-41. [PMID: 24920749 DOI: 10.1093/icb/icu068] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Reduced reproduction extends lifespan of females in many animals. To test the effects of reproduction on storage of macronutrients, we block reproductive output in the lubber grasshopper by injecting RNAi against the precursor to egg-yolk protein, vitellogenin, in early adulthood. Controls were injected with either buffer or RNAi against the major storage protein in the hemolymph, hexamerin-90. Vitellogenin RNAi greatly reduced both levels of mRNA for vitellogenin and ovarian growth, in comparison to both controls. Fat body mass was increased upon vitellogenin RNAi, but concentrations of the three hexameric storage proteins from the hemolymph were not. Surprisingly, hemolymph vitellogenin levels were increased upon vitellogenin RNAi. Total reproductive protein (hemolymph vitellogenin plus ovarian vitellin) was unchanged by vitellogenin RNAi, as reproductive protein was diverted to the hemolymph. Similarly, the increased lipid storage upon vitellogenin RNAi was largely attributable to the reduction in lipid in the ovary, due to decreased ovarian growth. A BLAST search revealed that the 515 bp sequence of vitellogenin used for RNAi had three 11 bp regions identical to the vitellogenin receptor of the cockroach Leucophaea maderae. This suggests that our treatment, in addition to reducing levels of vitellogenin transcript, may have also blocked transport of vitellogenin from the hemolymph to the ovary. This would be consistent with halted ovarian growth simultaneous with high levels of vitellogenin in the hemolymph. Nonetheless, the accumulation of vitellogenin, instead of hexameric storage proteins, is inconsistent with a simple model of the trade-off between reproduction and storage. This was observed in young females; future studies will address whether investment of proteins may shift to the soma as individuals age. Overall, our results suggest that blockage of reproduction in young grasshoppers redirects lipids to storage and reproductive proteins to the hemolymph.
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Affiliation(s)
- Derek R Tokar
- *Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL 32224, USA; Neurobiology Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Entomology and Nematology, University of Florida, PO Box 110620, Bldg. 970 Natural Area Drive, Gainesville, FL 32611, USA
| | - Katherine A Veleta
- *Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL 32224, USA; Neurobiology Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Entomology and Nematology, University of Florida, PO Box 110620, Bldg. 970 Natural Area Drive, Gainesville, FL 32611, USA *Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL 32224, USA; Neurobiology Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Entomology and Nematology, University of Florida, PO Box 110620, Bldg. 970 Natural Area Drive, Gainesville, FL 32611, USA
| | - Joseph Canzano
- *Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL 32224, USA; Neurobiology Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Entomology and Nematology, University of Florida, PO Box 110620, Bldg. 970 Natural Area Drive, Gainesville, FL 32611, USA
| | - Daniel A Hahn
- *Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL 32224, USA; Neurobiology Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Entomology and Nematology, University of Florida, PO Box 110620, Bldg. 970 Natural Area Drive, Gainesville, FL 32611, USA
| | - John D Hatle
- *Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL 32224, USA; Neurobiology Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Entomology and Nematology, University of Florida, PO Box 110620, Bldg. 970 Natural Area Drive, Gainesville, FL 32611, USA
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17
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Hatle JD, Kellenberger JW, Viray E, Smith AM, Hahn DA. Life-extending ovariectomy in grasshoppers increases somatic storage, but dietary restriction with an equivalent feeding rate does not. Exp Gerontol 2013; 48:966-72. [PMID: 23838534 DOI: 10.1016/j.exger.2013.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 06/11/2013] [Accepted: 06/24/2013] [Indexed: 11/29/2022]
Abstract
Reduced diet or reduced reproduction each extends lifespan in many animals. It is often thought that reduced reproduction and reduced diet may act through the same mechanisms. In grasshoppers, ovariectomy extends lifespan and reduces feeding to a level similar to that used for life extension by dietary restriction, further suggesting mechanistic overlap. Here, we measure the feeding rate of ovariectomized grasshoppers and, by manipulating feeding levels, create a sham-operated & dietary restricted group with matched daily feeding. Both groups show ~25% increased survivorship near the median age of mortality for fully fed and reproductive controls. Ovariectomy results in a doubling of fat body mass and hemolymph volume in comparison to both a feeding-matched dietary restriction group and a sham-operated & fully fed control, which do not differ from each other. Total anti-oxidant activity in the hemolymph and the skeletal muscle was unchanged upon ovariectomy or dietary restriction, so it does not appear to be a major factor in lifespan extension. Next, we measured mitochondrial counts using qPCR to determine mitochondrial cytochrome-b concentrations relative to nuclear (genomic) beta-actin. Mitochondrial counts in the ovariectomized group were lower than sham-operated and fully fed controls but not than the dietary restriction group. Last, in the fat body, transcript levels of hexamerin-90 (a hemolymph storage protein) were affected by neither ovariectomy nor dietary restriction. Hence, ovariectomy resulted in large magnitude increases in organismal storage. The matched-fed dietary restricted group differed from the ovariectomized group only in organismal storage, and not in any of the cellular parameters measured here. This study suggests that longevity via ovariectomy has distinct physiological mechanisms from longevity via dietary restriction in grasshoppers that are independent of daily feeding rate, particularly for protein and fat storage.
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Affiliation(s)
- John D Hatle
- University of North Florida, Department of Biology, Jacksonville, FL 32224, USA.
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18
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Hansen M, Flatt T, Aguilaniu H. Reproduction, fat metabolism, and life span: what is the connection? Cell Metab 2013; 17:10-9. [PMID: 23312280 PMCID: PMC3567776 DOI: 10.1016/j.cmet.2012.12.003] [Citation(s) in RCA: 220] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 10/23/2012] [Accepted: 12/06/2012] [Indexed: 11/20/2022]
Abstract
Reduced reproduction is associated with increased fat storage and prolonged life span in multiple organisms, but the underlying regulatory mechanisms remain poorly understood. Recent studies in several species provide evidence that reproduction, fat metabolism, and longevity are directly coupled. For instance, germline removal in the nematode Caenorhabditis elegans promotes longevity in part by modulating lipid metabolism through effects on fatty acid desaturation, lipolysis, and autophagy. Here, we review these recent studies and discuss the mechanisms by which reproduction modulates fat metabolism and life span. Elucidating the relationship between these processes could contribute to our understanding of age-related diseases including metabolic disorders.
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Affiliation(s)
- Malene Hansen
- Sanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and StemCell Research Center, Program of Development and Aging, La Jolla, CA, USA
| | - Thomas Flatt
- Institute of Population Genetics, Department of Biomedical Sciences, Vetmeduni Vienna, Vienna, Austria
- Wissenschaftskolleg zu Berlin, Institute for Advanced Study, Berlin, Germany
- As of December 2012: Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Hugo Aguilaniu
- Ecole normale supérieure de Lyon; CNRS; Université de Lyon Claude Bernard; Molecular Biology of the Cell Laboratory/UMR5239, Lyon, France
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Judd ET, Wessels FJ, Drewry MD, Grove M, Wright K, Hahn DA, Hatle JD. Ovariectomy in grasshoppers increases somatic storage, but proportional allocation of ingested nutrients to somatic tissues is unchanged. Aging Cell 2011; 10:972-9. [PMID: 21834847 PMCID: PMC3215815 DOI: 10.1111/j.1474-9726.2011.00737.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Reduced reproduction increases storage and extends lifespan in several animal species. The disposable soma hypothesis suggests this life extension occurs by shifting allocation of ingested nutrients from reproduction to the soma. A great deal of circumstantial evidence supports this hypothesis, but no direct tracking of nutrients has been performed in animals that are long-lived because of direct reduction in reproduction. Here, we use the stable isotopes to track carbon and nitrogen from ingestion to somatic organs in long-lived, ovariectomized grasshoppers. Three estimates of somatic storage (viz., quantity of hemolymph storage proteins, amount of femur muscle carbohydrates, and size of the fat body) all doubled upon ovariectomy. In stark contrast, ovariectomy did not increase the proportion of these tissues that were made from recently ingested foods. In other words, the physiology underlying relative allocation to these somatic tissues was not affected by ovariectomy. Thus, at the level of whole tissue storage, these results are consistent with a trade-off between reproduction and longevity. In contrast, our stable isotope data are inconsistent with the prediction that enhanced storage in ovariectomized females results from a physiological shift in allocation of ingested nutrients.
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Affiliation(s)
- Evan T Judd
- Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL 32224, USA
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