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Sirman AE, Schmidt JE, Clark ME, Kittilson JD, Reed WL, Heidinger BJ. Compensatory Growth Is Accompanied by Changes in Insulin-Like Growth Factor 1 but Not Markers of Cellular Aging in a Long-Lived Seabird. Am Nat 2023; 202:78-91. [PMID: 37384761 DOI: 10.1086/724599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2023]
Abstract
AbstractDeveloping organisms often plastically modify growth in response to environmental circumstances, which may be adaptive but is expected to entail long-term costs. However, the mechanisms that mediate these growth adjustments and any associated costs are less well understood. In vertebrates, one mechanism that may be important in this context is the highly conserved signaling factor insulin-like growth factor 1 (IGF-1), which is frequently positively related to postnatal growth and negatively related to longevity. To test this idea, we exposed captive Franklin's gulls (Leucophaeus pipixcan) to a physiologically relevant nutritional stressor by restricting food availability during postnatal development and examined the effects on growth, IGF-1, and two potential biomarkers of cellular and organismal aging (oxidative stress and telomeres). During food restriction, experimental chicks gained body mass more slowly and had lower IGF-1 levels than controls. Following food restriction, experimental chicks underwent compensatory growth, which was accompanied by an increase in IGF-1 levels. Interestingly, however, there were no significant effects of the experimental treatment or of variation in IGF-1 levels on oxidative stress or telomeres. These findings suggest that IGF-1 is responsive to changes in resource availability but is not associated with increased markers of cellular aging during development in this relatively long-lived species.
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Heidinger BJ, Slowinski SP, Sirman AE, Kittilson J, Gerlach NM, Ketterson ED. Experimentally elevated testosterone shortens telomeres across years in a free-living songbird. Mol Ecol 2022; 31:6216-6223. [PMID: 33503312 DOI: 10.1111/mec.15819] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 12/29/2020] [Accepted: 01/19/2021] [Indexed: 01/31/2023]
Abstract
Reproductive investment often comes at a cost to longevity, but the mechanisms that underlie these long-term effects are not well understood. In male vertebrates, elevated testosterone has been shown to increase reproductive success, but simultaneously to decrease survival. One factor that may contribute to or serve as a biomarker of these long-term effects of testosterone on longevity is telomeres, which are often positively related to lifespan and have been shown to shorten in response to reproduction. In this longitudinal study, we measured the effects of experimentally elevated testosterone on telomere shortening in free-living, male dark-eyed juncos (Junco hyemalis carolinensis), a system in which the experimental elevation of testosterone has previously been shown to increase reproductive success and reduce survival. We found a small, significant effect of testosterone treatment on telomeres, with testosterone-treated males exhibiting significantly greater telomere shortening with age than controls. These results are consistent with the hypothesis that increased telomere shortening may be a long-term cost of elevated testosterone exposure. As both testosterone and telomeres are conserved physiological mechanisms, our results suggest that their interaction may apply broadly to the long-term costs of reproduction in male vertebrates.
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Affiliation(s)
- Britt J Heidinger
- Biological Sciences Department, North Dakota State University, Fargo, ND, USA
| | | | - Aubrey E Sirman
- Biological Sciences Department, North Dakota State University, Fargo, ND, USA
| | - Jeffrey Kittilson
- Biological Sciences Department, North Dakota State University, Fargo, ND, USA
| | - Nicole M Gerlach
- Department of Biology, University of Florida, Gainesville, FL, USA
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Young RC, Westneat DF, Vangorder-Braid J, Sirman AE, Siller SJ, Kittilson J, Ghimire A, Heidinger BJ. Stressors interact across generations to influence offspring telomeres and survival. Proc Biol Sci 2022; 289:20220868. [PMID: 36069016 PMCID: PMC9449473 DOI: 10.1098/rspb.2022.0868] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 08/15/2022] [Indexed: 11/12/2022] Open
Abstract
Parental stress often has long-term consequences for offspring. However, the mechanisms underlying these effects and how they are shaped by conditions offspring subsequently experience are poorly understood. Telomeres, which often shorten in response to stress and predict longevity, may contribute to, and/or reflect these cross-generational effects. Traditionally, parental stress is expected to have negative effects on offspring telomeres, but experimental studies in captive animals suggest that these effects may depend on the subsequent conditions that offspring experience. Yet, the degree to which parental stress influences and interacts with stress experienced by offspring to affect offspring telomeres and survival in free-living organisms is unknown. To assess this, we experimentally manipulated the stress exposure of free-living parent and offspring house sparrows (Passer domesticus). We found a weak, initial, negative effect of parental stress on offspring telomeres, but this effect was no longer evident at the end of post-natal development. Instead, the effects of parental stress depended on the natural sources of stress that offspring experienced during post-natal development whereby some outcomes were improved under more stressful rearing conditions. Thus, the effects of parental stress on offspring telomeres and survival are context-dependent and may involve compensatory mechanisms of potential benefit under some circumstances.
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Affiliation(s)
- Rebecca C. Young
- Department of Biological Sciences, North Dakota State University, Fargo, ND, USA
| | | | | | - Aubrey E. Sirman
- Department of Biological Sciences, North Dakota State University, Fargo, ND, USA
| | - Stefanie J. Siller
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY, USA
| | - Jeffrey Kittilson
- Department of Biological Sciences, North Dakota State University, Fargo, ND, USA
| | - Anuj Ghimire
- Department of Biological Sciences, North Dakota State University, Fargo, ND, USA
| | - Britt J. Heidinger
- Department of Biological Sciences, North Dakota State University, Fargo, ND, USA
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Vangorder-Braid JT, Sirman AE, Kucera AC, Kittilson JD, Kibble TM, Heidinger BJ. TA-65 does not increase telomere length during post-natal development in house sparrow chicks (Passer domesticus). J Exp Zool A Ecol Integr Physiol 2021; 335:359-366. [PMID: 33651921 DOI: 10.1002/jez.2449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 01/11/2021] [Accepted: 02/03/2021] [Indexed: 11/09/2022]
Abstract
Telomeres, protective caps at the end of chromosomes, are often positively related to lifespan and are thought to be an important mechanism of organismal aging. To better understand the casual relationships between telomere length and longevity, it is essential to be able to experimentally manipulate telomere dynamics (length and loss rate). Previous studies suggest that exposure to TA-65, an extract from the Chinese root Astragalus membranaceus, activates telomerase, lengthens telomeres, increases the growth of keratin-based structures, and boosts the immune system in adults. However, telomere loss is expected to be greatest during early life but whether TA-65 has similar effects during this life stage is currently unknown. Here, we experimentally exposed free-living house sparrow (Passer domesticus) chicks to TA-65 during post-natal development and examined the effects on telomere length and loss, growth of keratin-based structures, and a measure of cellular immunity. Contrary to expectation, the growth of keratin-based structures was reduced in TA-65 chicks and in the second year of the study, chicks exposed to TA-65 experienced more telomere loss than controls. Thus, the effects of TA-65 on telomeres and keratin-based structures differ across life stages and future research will be necessary to determine the mechanisms underlying these age-specific effects.
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Affiliation(s)
- Jennifer T Vangorder-Braid
- Department of Biological Sciences, North Dakota State University, Fargo, North Dakota, USA.,Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, Minnesota, USA
| | - Aubrey E Sirman
- Department of Biological Sciences, North Dakota State University, Fargo, North Dakota, USA.,Arrupe College of Loyola University Chicago, Chicago, Illinois, USA
| | - Aurelia C Kucera
- Department of Biological Sciences, North Dakota State University, Fargo, North Dakota, USA
| | - Jeffrey D Kittilson
- Department of Biological Sciences, North Dakota State University, Fargo, North Dakota, USA
| | - Tania M Kibble
- Department of Biological Sciences, North Dakota State University, Fargo, North Dakota, USA
| | - Britt J Heidinger
- Department of Biological Sciences, North Dakota State University, Fargo, North Dakota, USA
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Schmidt JE, Sirman AE, Kittilson JD, Clark ME, Reed WL, Heidinger BJ. Telomere correlations during early life in a long-lived seabird. Exp Gerontol 2016; 85:28-32. [DOI: 10.1016/j.exger.2016.09.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 08/23/2016] [Accepted: 09/11/2016] [Indexed: 01/01/2023]
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Mowry AV, Kavazis AN, Sirman AE, Potts WK, Hood WR. Reproduction Does Not Adversely Affect Liver Mitochondrial Respiratory Function but Results in Lipid Peroxidation and Increased Antioxidants in House Mice. PLoS One 2016; 11:e0160883. [PMID: 27537547 PMCID: PMC4990174 DOI: 10.1371/journal.pone.0160883] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 07/26/2016] [Indexed: 12/31/2022] Open
Abstract
Reproduction is thought to come at a cost to longevity. Based on the assumption that increased energy expenditure during reproduction is associated with increased free-radical production by mitochondria, oxidative damage has been suggested to drive this trade-off. We examined the impact of reproduction on liver mitochondrial function by utilizing post-reproductive and non-reproductive house mice (Mus musculus) living under semi-natural conditions. The age-matched post-reproductive and non-reproductive groups were compared after the reproductive females returned to a non-reproductive state, so that both groups were in the same physiological state at the time the liver was collected. Despite increased oxidative damage (p = 0.05) and elevated CuZnSOD (p = 0.002) and catalase (p = 0.04) protein levels, reproduction had no negative impacts on the respiratory function of liver mitochondria. Specifically, in a post-reproductive, maintenance state the mitochondrial coupling (i.e., respiratory control ratio) of mouse livers show no negative impacts of reproduction. In fact, there was a trend (p = 0.059) to suggest increased maximal oxygen consumption by liver mitochondria during the ADP stimulated state (i.e., state 3) in post-reproduction. These findings suggest that oxidative damage may not impair mitochondrial respiratory function and question the role of mitochondria in the trade-off between reproduction and longevity. In addition, the findings highlight the importance of quantifying the respiratory function of mitochondria in addition to measuring oxidative damage.
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Affiliation(s)
- Annelise V. Mowry
- Department of Biological Sciences, Auburn University, Auburn, Alabama, United States of America
| | - Andreas N. Kavazis
- School of Kinesiology, Auburn University, Auburn, Alabama, United States of America
| | - Aubrey E. Sirman
- Department of Biological Sciences, Auburn University, Auburn, Alabama, United States of America
| | - Wayne K. Potts
- Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
| | - Wendy R. Hood
- Department of Biological Sciences, Auburn University, Auburn, Alabama, United States of America
- * E-mail:
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Bentz AB, Sirman AE, Wada H, Navara KJ, Hood WR. Relationship between maternal environment and DNA methylation patterns of estrogen receptor alpha in wild Eastern Bluebird (Sialia sialis) nestlings: a pilot study. Ecol Evol 2016; 6:4741-52. [PMID: 27547309 PMCID: PMC4979703 DOI: 10.1002/ece3.2162] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 04/11/2016] [Accepted: 04/13/2016] [Indexed: 12/18/2022] Open
Abstract
There is mounting evidence that, across taxa, females breeding in competitive environments tend to allocate more testosterone to their offspring prenatally and these offspring typically have more aggressive and faster‐growing phenotypes. To date, no study has determined the mechanisms mediating this maternal effect's influence on offspring phenotype. However, levels of estrogen receptor alpha (ERα) gene expression are linked to differences in early growth and aggression; thus, maternal hormones may alter gene regulation, perhaps via DNA methylation, of ERα in offspring during prenatal development. We performed a pilot study to examine natural variation in testosterone allocation to offspring through egg yolks in wild Eastern Bluebirds (Sialia sialis) in varying breeding densities and percent DNA methylation of CG dinucleotides in the ERα promoter in offspring brain regions associated with growth and behavior. We hypothesized that breeding density would be positively correlated with yolk testosterone, and prenatal exposure to maternal‐derived yolk testosterone would be associated with greater offspring growth and decreased ERα promoter methylation. Yolk testosterone concentration was positively correlated with breeding density, nestling growth rate, and percent DNA methylation of one out of five investigated CpG sites (site 3) in the diencephalon ERα promoter, but none in the telencephalon (n = 10). Percent DNA methylation of diencephalon CpG site 3 was positively correlated with growth rate. These data suggest a possible role for epigenetics in mediating the effects of the maternal environment on offspring phenotype. Experimentally examining this mechanism with a larger sample size in future studies may help elucidate a prominent way in which animals respond to their environment. Further, by determining the mechanisms that mediate maternal effects, we can begin to understand the potential for the heritability of these mechanisms and the impact that maternal effects are capable of producing at an evolutionary scale.
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Affiliation(s)
- Alexandra B Bentz
- Poultry Science Department University of Georgia 203 Poultry Science Bldg. Athens Georigia 30602
| | - Aubrey E Sirman
- Department of Biological Sciences Auburn University 101 Life Science Building Auburn Alabama 36849
| | - Haruka Wada
- Department of Biological Sciences Auburn University 101 Life Science Building Auburn Alabama 36849
| | - Kristen J Navara
- Poultry Science Department University of Georgia 203 Poultry Science Bldg. Athens Georigia 30602
| | - Wendy R Hood
- Department of Biological Sciences Auburn University 101 Life Science Building Auburn Alabama 36849
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