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The paraventricular thalamus serves as a nexus in the regulation of stress and immunity. Brain Behav Immun 2021; 95:36-44. [PMID: 33540073 DOI: 10.1016/j.bbi.2021.01.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 01/11/2021] [Accepted: 01/20/2021] [Indexed: 11/23/2022] Open
Abstract
Many temperate zone animals exhibit seasonal rhythms in physiology and behavior, including seasonal cycles of reproduction, energetics, stress responsiveness, and immune function, among many others. These rhythms are driven by seasonal changes in the duration of pineal melatonin secretion. The neural melatonin target tissues that mediate several of these rhythms have been identified, though the target(s) mediating melatonin's regulation of glucocorticoid secretion, immune cell numbers, and bacterial killing capacity remain unspecified. The present results indicate that one melatonin target tissue, the paraventricular nucleus of the thalamus (PVT), is necessary for the expression of these seasonal rhythms. Thus, while radiofrequency ablations of the PVT failed to alter testicular and body mass response to short photoperiod exposure, they did block the effect of short day lengths on cortisol secretion and bacterial killing efficacy. These results are consistent with the independent regulation by separate neural circuits of several physiological traits that vary seasonally in mammals.
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2
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Kronfeld-Schor N, Stevenson TJ, Nickbakhsh S, Schernhammer ES, Dopico XC, Dayan T, Martinez M, Helm B. Drivers of Infectious Disease Seasonality: Potential Implications for COVID-19. J Biol Rhythms 2021; 36:35-54. [PMID: 33491541 PMCID: PMC7924107 DOI: 10.1177/0748730420987322] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Not 1 year has passed since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19). Since its emergence, great uncertainty has surrounded the potential for COVID-19 to establish as a seasonally recurrent disease. Many infectious diseases, including endemic human coronaviruses, vary across the year. They show a wide range of seasonal waveforms, timing (phase), and amplitudes, which differ depending on the geographical region. Drivers of such patterns are predominantly studied from an epidemiological perspective with a focus on weather and behavior, but complementary insights emerge from physiological studies of seasonality in animals, including humans. Thus, we take a multidisciplinary approach to integrate knowledge from usually distinct fields. First, we review epidemiological evidence of environmental and behavioral drivers of infectious disease seasonality. Subsequently, we take a chronobiological perspective and discuss within-host changes that may affect susceptibility, morbidity, and mortality from infectious diseases. Based on photoperiodic, circannual, and comparative human data, we not only identify promising future avenues but also highlight the need for further studies in animal models. Our preliminary assessment is that host immune seasonality warrants evaluation alongside weather and human behavior as factors that may contribute to COVID-19 seasonality, and that the relative importance of these drivers requires further investigation. A major challenge to predicting seasonality of infectious diseases are rapid, human-induced changes in the hitherto predictable seasonality of our planet, whose influence we review in a final outlook section. We conclude that a proactive multidisciplinary approach is warranted to predict, mitigate, and prevent seasonal infectious diseases in our complex, changing human-earth system.
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Affiliation(s)
| | - T. J. Stevenson
- Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, UK
| | - S. Nickbakhsh
- Institute of Infection, Immunity & Inflammation, MRC-University of Glasgow Centre for Virus Research, University of Glasgow, Glasgow, UK
| | - E. S. Schernhammer
- Department of Epidemiology, Center for Public Health, Medical University of Vienna, Vienna, Austria
- Channing Division of Network Medicine, Harvard Medical School, Boston, MA, USA
| | - X. C. Dopico
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - T. Dayan
- School of Zoology, The Steinhardt Museum of Natural History, Tel Aviv University, Tel Aviv, Israel
| | - M. Martinez
- School of Public Health, Columbia University, New York City, NY, USA
| | - B. Helm
- Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, UK
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
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3
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Foster CG, Landowski LM, Sutherland BA, Howells DW. Differences in fatigue-like behavior in the lipopolysaccharide and poly I:C inflammatory animal models. Physiol Behav 2021; 232:113347. [PMID: 33529685 DOI: 10.1016/j.physbeh.2021.113347] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 01/18/2021] [Accepted: 01/29/2021] [Indexed: 11/30/2022]
Abstract
Central fatigue is a condition associated with impairment of the central nervous system often leading to the manifestation of a range of debilitating symptoms. Fatigue can be a consequence of systemic inflammation following an infection. Administration of lipopolysaccharide (LPS) and polyriboinosinic:polyribocytidlic (poly I:C) to animals can induce systemic inflammation by mimicking a bacterial or viral infection respectively and therefore have been used as models of fatigue. We evaluated a range of phenotypic behaviors exhibited in the LPS and poly I:C animal models to assess whether they adequately replicate fatigue symptomology in humans. In addition to standard observation- and intervention-based behavioral assessments, we used powerful in-cage monitoring technology to quantify rodent behavior without external interference. LPS and poly I:C treated Sprague Dawley rats displayed 'sickness behaviors' of elevated temperature, weight loss and reduced activity in the open field test and with in-cage monitoring within 24 h post-treatment, but only LPS-treated rats displayed these behaviors beyond these acute timepoints. Once sickness behavior diminished, LPS-treated rats exhibited an increase in reward-seeking and motivation behaviors. Overall, these results suggest that the LPS animal model produces an extensive and sustained fatigue-like phenotype, whereas the poly I:C model only produced acute effects. Our results suggest that the LPS animal model is a more suitable candidate for further studies on central fatigue-like behavior.
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Affiliation(s)
- Catherine G Foster
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, Australia
| | - Lila M Landowski
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, Australia
| | - Brad A Sutherland
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, Australia
| | - David W Howells
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, Australia.
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4
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Onishi KG, Maneval AC, Cable EC, Tuohy MC, Scasny AJ, Sterina E, Love JA, Riggle JP, Malamut LK, Mukerji A, Novo JS, Appah-Sampong A, Gary JB, Prendergast BJ. Circadian and circannual timescales interact to generate seasonal changes in immune function. Brain Behav Immun 2020; 83:33-43. [PMID: 31351184 DOI: 10.1016/j.bbi.2019.07.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 07/14/2019] [Accepted: 07/23/2019] [Indexed: 12/22/2022] Open
Abstract
Annual changes in day length enhance or suppress diverse aspects of immune function, giving rise to seasonal cycles of illness and mortality. The daily light-dark cycle also entrains circadian rhythms in immunity. Most published reports on immunological seasonality rely on measurements or interventions performed only at one point in the day. Because there can be no perfect matching of circadian phase across photoperiods of different duration, the manner in which these timescales interact to affect immunity is not understood. We examined whether photoperiodic changes in immune function reflect phenotypic changes that persist throughout the daily cycle, or merely reflect photoperiodic shifts in the circadian phase alignment of immunological rhythms. Diurnal rhythms in blood leukocyte trafficking, infection induced sickness responses, and delayed-type hypersensitivity skin inflammatory responses were examined at high-frequency sampling intervals (every 3 h) in Siberian hamsters (Phodopus sungorus) following immunological adaptation to summer or winter photoperiods. Photoperiod profoundly enhanced or suppressed immune function, in a trait-specific manner, and we were unable to identify a phase alignment of diurnal waveforms which eliminated these enhancing and suppressing effects of photoperiod. These results support the hypothesis that seasonal timescales affect immunity via mechanisms independent of circadian entrainment of the immunological circadian waveform.
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Affiliation(s)
- Kenneth G Onishi
- Department of Psychology and Institute for Mind and Biology, University of Chicago, Chicago, IL 60637, United States.
| | - Andrew C Maneval
- Department of Psychology and Institute for Mind and Biology, University of Chicago, Chicago, IL 60637, United States
| | - Erin C Cable
- Department of Psychology and Institute for Mind and Biology, University of Chicago, Chicago, IL 60637, United States
| | - Mary Claire Tuohy
- Department of Psychology and Institute for Mind and Biology, University of Chicago, Chicago, IL 60637, United States
| | - Andrew J Scasny
- Department of Psychology and Institute for Mind and Biology, University of Chicago, Chicago, IL 60637, United States
| | - Evelina Sterina
- Department of Psychology and Institute for Mind and Biology, University of Chicago, Chicago, IL 60637, United States
| | - Jharnae A Love
- Department of Psychology and Institute for Mind and Biology, University of Chicago, Chicago, IL 60637, United States
| | - Jonathan P Riggle
- Department of Psychology and Institute for Mind and Biology, University of Chicago, Chicago, IL 60637, United States
| | - Leah K Malamut
- Department of Psychology and Institute for Mind and Biology, University of Chicago, Chicago, IL 60637, United States
| | - Aashna Mukerji
- Department of Psychology and Institute for Mind and Biology, University of Chicago, Chicago, IL 60637, United States
| | - Jennifer S Novo
- Department of Psychology and Institute for Mind and Biology, University of Chicago, Chicago, IL 60637, United States
| | - Abena Appah-Sampong
- Department of Psychology and Institute for Mind and Biology, University of Chicago, Chicago, IL 60637, United States
| | - Joseph B Gary
- Department of Psychology and Institute for Mind and Biology, University of Chicago, Chicago, IL 60637, United States
| | - Brian J Prendergast
- Department of Psychology and Institute for Mind and Biology, University of Chicago, Chicago, IL 60637, United States; Committee on Neurobiology, University of Chicago, Chicago, IL 60637, United States; Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, University of Chicago, Chicago, IL 60637, United States
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5
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Onishi KG, Prendergast BJ, Stevenson TJ. Trait-specific effects of exogenous triiodothyronine on cytokine and behavioral responses to simulated systemic infection in male Siberian hamsters. Horm Behav 2019; 110:90-97. [PMID: 30826308 DOI: 10.1016/j.yhbeh.2019.02.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 02/25/2019] [Accepted: 02/26/2019] [Indexed: 11/21/2022]
Abstract
Seasonal changes in day length enhance and suppress immune function in a trait-specific manner. In Siberian hamsters (Phodopus sungorus) winter-like short days (SDs) increase blood leukocyte concentrations and adaptive T cell dependent immune responses, but attenuate innate inflammatory responses to simulated infections. Thyroid hormone (TH) signaling also changes seasonally and has been implicated in modulation of the reproductive axis by day length. Immunologically, TH administration in long days (LD) enhances adaptive immune responses in male Siberian hamsters, mimicking effects of SDs. This experiment tested the hypothesis that T3 is also sufficient to mimic the effects of SD on innate immune responses. Adult male hamsters housed in LDs were pretreated with triiodothyronine (T3; 1 μg, s.c.) or saline (VEH) daily for 6 weeks; additional positive controls were housed in SD and received VEH, after which cytokine, behavioral, and physiological responses to simulated bacterial infection (lipopolysaccharide; LPS) were evaluated. SD pretreatment inhibited proinflammatory cytokine mRNA expression (i.e. interleukin 1β, nuclear factor kappa-light-chain-enhancer of activated B cells). In addition, the magnitude and persistence of anorexic and cachectic responses to LPS were also lower in SD hamsters, and LPS-induced inhibition of nest building behavior was absent in SD. T3 treatments failed to affect behavioral (food intake, nest building) or somatic (body mass) responses to LPS in LD hamsters, but one CNS cytokine response to LPS (e.g., hypothalamic TNFα) was augmented by T3. Together these data implicate thyroid hormone signaling in select aspects of innate immune responses to seasonal changes in day length.
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Affiliation(s)
- Kenneth G Onishi
- Department of Psychology, Institute for Mind and Biology, University of Chicago, Chicago, IL 60637, USA.
| | - Brian J Prendergast
- Department of Psychology, Institute for Mind and Biology, University of Chicago, Chicago, IL 60637, USA
| | - Tyler J Stevenson
- Inst. Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, UK
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6
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Sylvia KE, Demas GE. A Return to Wisdom: Using Sickness Behaviors to Integrate Ecological and Translational Research. Integr Comp Biol 2017; 57:1204-1213. [PMID: 28992281 PMCID: PMC5886345 DOI: 10.1093/icb/icx051] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Sickness is typically characterized by fever, anorexia, cachexia, and reductions in social, pleasurable, and sexual behaviors. These responses can be displayed at varying intensities both within and among individuals, and the adaptive nature of sickness responses can be demonstrated by the context-dependent nature of their expression. The study of sickness has become an important area of investigation for researchers in a wide range of areas, including psychoneuroimmunology (PNI) and ecoimmunology (EI). The general goal of PNI is to identify key interactions among the nervous, endocrine and immune systems and behavior, and how disruptions in these processes might contribute to disease states. EI, in turn, has been established more recently within the perspectives of ecology and evolutionary biology, and is aimed more at understanding natural variation in immune function and sickness responses within a broadly integrative, organismal, and evolutionary context. The goal of this review is to examine the literature on sickness from both basic and biomedical perspectives within PNI and EI and to demonstrate how the integrative study of sickness behavior can serve as an integrating agent to connect ecological and translational approaches to the study of disease. By focusing on a set of specific exemplars, including the energetics of sickness, social context, and environmental influences on sickness, we hope to accomplish the larger goal of developing a common synthetic framework to understand sickness from multiple levels of analysis and varying perspectives across the fields of PNI and EI. By applying this integrative approach to sickness, we will be able to develop a more comprehensive view of sickness as a suite of adaptive responses rather than the simply deleterious consequences of illness.
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Affiliation(s)
- Kristyn E Sylvia
- Department of Biology, Center for the Integrative Study of Animal Behavior, and Program in Neuroscience Indiana University, Bloomington, IN 47405, USA
| | - Gregory E Demas
- Department of Biology, Center for the Integrative Study of Animal Behavior, and Program in Neuroscience Indiana University, Bloomington, IN 47405, USA
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7
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Carlton ED, Demas GE. Glucose and insulin modulate sickness responses in male Siberian hamsters. Gen Comp Endocrinol 2017; 242:83-91. [PMID: 26542473 PMCID: PMC4853293 DOI: 10.1016/j.ygcen.2015.11.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 09/20/2015] [Accepted: 11/01/2015] [Indexed: 01/04/2023]
Abstract
Mounting a sickness response is an energetically expensive task and requires precise balancing of energy allocation to ensure pathogen clearance while avoiding compromising energy reserves. Sickness intensity has previously been shown to be modulated by food restriction, body mass, and hormonal signals of energy. In the current study, we tested the hypothesis that sickness intensity is modulated by glucose availability and an endocrine signal of glucose availability, insulin. We utilized male Siberian hamsters (Phodopus sungorus) and predicted that pharmacological induction of glucoprivation with 2-deoxy-d-glucose (2-DG), a non-metabolizable glucose analog that disrupts glycolysis, would attenuate energetically expensive sickness symptoms. Alternatively, we predicted that treatment of animals with insulin would enhance energetically expensive sickness symptoms, as insulin would act as a signal of increased glucose availability. Upon experimental treatment with lipopolysaccharide (LPS), we found that glucose deprivation resulted in increased sickness-induced hypothermia as compared to control- and insulin-treated animals; however, it did not have any effects on sickness-induced anorexia or body mass loss. Insulin treatment resulted in an unexpectedly exaggerated sickness response in animals of lesser body masses; however, in animals of greater body masses, insulin actually attenuated sickness-induced body mass loss and had no effects on hypothermia or anorexia. The effects of insulin on sickness severity may be modulated by sensitivity to sickness-induced hypoglycemia. Collectively, these results demonstrate that both glucose availability and signals of glucose availability can modulate the intensity of energetically expensive sickness symptoms, but their effects differ among different sickness symptoms and are sensitive to energetic context.
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Affiliation(s)
- Elizabeth D Carlton
- Department of Biology, Program in Neuroscience and Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA.
| | - Gregory E Demas
- Department of Biology, Program in Neuroscience and Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA
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8
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Martinez-Bakker M, Helm B. The influence of biological rhythms on host-parasite interactions. Trends Ecol Evol 2015; 30:314-26. [PMID: 25907430 DOI: 10.1016/j.tree.2015.03.012] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 02/22/2015] [Accepted: 03/12/2015] [Indexed: 01/09/2023]
Abstract
Biological rhythms, from circadian control of cellular processes to annual cycles in life history, are a main structural element of biology. Biological rhythms are considered adaptive because they enable organisms to partition activities to cope with, and take advantage of, predictable fluctuations in environmental conditions. A flourishing area of immunology is uncovering rhythms in the immune system of animals, including humans. Given the temporal structure of immunity, and rhythms in parasite activity and disease incidence, we propose that the intersection of chronobiology, disease ecology, and evolutionary biology holds the key to understanding host-parasite interactions. Here, we review host-parasite interactions while explicitly considering biological rhythms, and propose that rhythms: influence within-host infection dynamics and transmission between hosts, might account for diel and annual periodicity in host-parasite systems, and can lead to a host-parasite arms race in the temporal domain.
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Affiliation(s)
- Micaela Martinez-Bakker
- Department of Ecology & Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Barbara Helm
- Institute for Biodiversity, Animal Health, and Comparative Medicine, University of Glasgow, Glasgow, UK
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9
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Carlton ED, Demas GE. Body mass affects seasonal variation in sickness intensity in a seasonally breeding rodent. ACTA ACUST UNITED AC 2015; 218:1667-76. [PMID: 25852068 DOI: 10.1242/jeb.120576] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 04/01/2015] [Indexed: 01/20/2023]
Abstract
Species that display seasonal variation in sickness intensity show the most intense response in the season during which they have the highest body mass, suggesting that sickness intensity may be limited by an animal's energy stores. Siberian hamsters (Phodopus sungorus) display lower body masses and less intense sickness when housed in short, winter-like days as opposed to long, summer-like days. To determine whether reduced sickness intensity displayed by short-day hamsters is a product of seasonal changes in body mass, we food restricted long-day hamsters so that they exhibited body mass loss that mimicked the natural photoperiod-induced loss of body mass in short-day hamsters. We then experimentally induced sickness with lipopolysaccharide (LPS) and compared sickness responses among long-day food-restricted and long- and short-day ad libitum fed groups, predicting that long-day food-restricted hamsters would show sickness responses comparable to those of short-day ad libitum fed hamsters and attenuated in comparison to long-day ad libitum fed hamsters. We found that long-day food-restricted hamsters showed attenuated LPS-induced anorexia, loss of body mass and hypothermia compared with long-day ad libitum fed animals; however, anorexia remained elevated in long-day food-restricted animals compared with short-day ad libitum fed animals. Additionally, LPS-induced anhedonia and decreases in nest building were not influenced by body mass. Results of hormone assays suggest that cortisol levels could play a role in the attenuation of sickness in long-day food-restricted hamsters, indicating that future research should target the roles of glucocorticoids and natural variation in energy stores in seasonal sickness variation.
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Affiliation(s)
- Elizabeth D Carlton
- Department of Biology, Program in Neuroscience and Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA
| | - Gregory E Demas
- Department of Biology, Program in Neuroscience and Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA
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10
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Weil ZM, Borniger JC, Cisse YM, Abi Salloum BA, Nelson RJ. Neuroendocrine control of photoperiodic changes in immune function. Front Neuroendocrinol 2015; 37:108-18. [PMID: 25456047 PMCID: PMC4402123 DOI: 10.1016/j.yfrne.2014.10.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 10/07/2014] [Accepted: 10/09/2014] [Indexed: 12/29/2022]
Abstract
Seasonal variation in immune function putatively maximizes survival and reproductive success. Day length (photoperiod) is the most potent signal for time of year. Animals typically organize breeding, growth, and behavior to adapt to spatial and temporal niches. Outside the tropics individuals monitor photoperiod to support adaptations favoring survival and reproductive success. Changes in day length allow anticipation of seasonal changes in temperature and food availability that are critical for reproductive success. Immune function is typically bolstered during winter, whereas reproduction and growth are favored during summer. We provide an overview of how photoperiod influences neuronal function and melatonin secretion, how melatonin acts directly and indirectly to govern seasonal changes in immune function, and the manner by which other neuroendocrine effectors such as glucocorticoids, prolactin, thyroid, and sex steroid hormones modulate seasonal variations in immune function. Potential future research avenues include commensal gut microbiota and light pollution influences on photoperiodic responses.
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Affiliation(s)
- Zachary M Weil
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA.
| | - Jeremy C Borniger
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Yasmine M Cisse
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Bachir A Abi Salloum
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Randy J Nelson
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
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11
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Stevenson TJ, Prendergast BJ. Photoperiodic time measurement and seasonal immunological plasticity. Front Neuroendocrinol 2015; 37:76-88. [PMID: 25456046 PMCID: PMC4405432 DOI: 10.1016/j.yfrne.2014.10.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 09/04/2014] [Accepted: 10/09/2014] [Indexed: 12/16/2022]
Abstract
Seasonal variations in immunity are common in nature, and changes in day length are sufficient to trigger enhancement and suppression of immune function in many vertebrates. Drawing primarily on data from Siberian hamsters, this review describes formal and physiological aspects of the neuroendocrine regulation of seasonal changes in mammalian immunity. Photoperiod regulates immunity in a trait-specific manner, and seasonal changes in gonadal hormone secretion and thyroid hormone signaling all participate in seasonal immunomodulation. Photoperiod-driven changes in the hamster reproductive and immune systems are associated with changes in iodothyronine deiodinase-mediated thyroid hormone signaling, but photoperiod exerts opposite effects on select aspects of the epigenetic regulation of reproductive neuroendocrine and lymphoid tissues. Photoperiodic changes in immunocompetence may explain a proportion of the annual variance in disease incidence and severity in nature, and provide a useful framework to help understand brain-immune interactions.
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Affiliation(s)
- Tyler J Stevenson
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK.
| | - Brian J Prendergast
- Department of Psychology and Institute for Mind and Biology, University of Chicago, Chicago, IL 60637, USA
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12
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Carlton ED, Demas GE. Leptin mediates seasonal variation in some but not all symptoms of sickness in Siberian hamsters. Horm Behav 2014; 66:802-11. [PMID: 25461974 PMCID: PMC4262702 DOI: 10.1016/j.yhbeh.2014.11.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 11/05/2014] [Accepted: 11/08/2014] [Indexed: 12/29/2022]
Abstract
Many seasonally breeding species, including Siberian hamsters (Phodopus sungorus), exhibit seasonal variation in sickness responses. One hypothesis regarding the mechanism of this variation is that sickness intensity tracks an animal's energetic state, such that sickness is attenuated in the season that an animal has the lowest fat stores. Energetic state may be signaled via leptin, an adipose hormone that provides a signal of fat stores. Siberian hamsters respond to extended housing in short, winter-like days by reducing fat stores and leptin levels, relative to those housed in long, summer-like days. Sickness responses are also attenuated in short-day hamsters as compared to long-day hamsters. We hypothesized that leptin provides a physiological signal by which seasonally breeding animals modulate sickness responses, such that animals with higher leptin levels show increased sickness intensity. To test this, we provided short-day hamsters with a long-day-like leptin signal and assessed their responses to lipopolysaccharide (LPS), a sickness-inducing antigen. We compared these responses to short-day vehicle-, long-day vehicle-, and long-day leptin-treated hamsters. Unexpectedly, LPS induced a hypothermic response (rather than fever) in all groups. Short-day vehicle-treated hamsters exhibited the greatest LPS-induced hypothermia, and leptin treatment attenuated this response, making hypothermia more long-day-like. Contrary to our hypothesis, short-day leptin-treated hamsters showed the least pronounced LPS-induced anorexia among all groups. These results suggest that leptin may mediate some but not all aspects of seasonal sickness variation in this species. Future studies should be targeted at determining roles of other energetic hormones in regulating seasonal sickness response variation.
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Affiliation(s)
- Elizabeth D Carlton
- Department of Biology, Program in Neuroscience and Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA.
| | - Gregory E Demas
- Department of Biology, Program in Neuroscience and Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA
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13
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McCusker RH, Kelley KW. Immune-neural connections: how the immune system's response to infectious agents influences behavior. ACTA ACUST UNITED AC 2013; 216:84-98. [PMID: 23225871 DOI: 10.1242/jeb.073411] [Citation(s) in RCA: 298] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Humans and animals use the classical five senses of sight, sound, touch, smell and taste to monitor their environment. The very survival of feral animals depends on these sensory perception systems, which is a central theme in scholarly research on comparative aspects of anatomy and physiology. But how do all of us sense and respond to an infection? We cannot see, hear, feel, smell or taste bacterial and viral pathogens, but humans and animals alike are fully aware of symptoms of sickness that are caused by these microbes. Pain, fatigue, altered sleep pattern, anorexia and fever are common symptoms in both sick animals and humans. Many of these physiological changes represent adaptive responses that are considered to promote animal survival, and this constellation of events results in sickness behavior. Infectious agents display a variety of pathogen-associated molecular patterns (PAMPs) that are recognized by pattern recognition receptors (PRRs). These PRR are expressed on both the surface [e.g. Toll-like receptor (TLR)-4] and in the cytoplasm [e.g. nucleotide-binding oligomerization domain (Nod)-like receptors] of cells of the innate immune system, primarily macrophages and dendritic cells. These cells initiate and propagate an inflammatory response by stimulating the synthesis and release of a variety of cytokines. Once an infection has occurred in the periphery, both cytokines and bacterial toxins deliver this information to the brain using both humoral and neuronal routes of communication. For example, binding of PRR can lead to activation of the afferent vagus nerve, which communicates neuronal signals via the lower brain stem (nucleus tractus solitarius) to higher brain centers such as the hypothalamus and amygdala. Blood-borne cytokines initiate a cytokine response from vascular endothelial cells that form the blood-brain barrier (BBB). Cytokines can also reach the brain directly by leakage through the BBB via circumventricular organs or by being synthesized within the brain, thus forming a mirror image of the cytokine milieu in the periphery. Although all cells within the brain are capable of initiating cytokine secretion, microglia have an early response to incoming neuronal and humoral stimuli. Inhibition of proinflammatory cytokines that are induced following bacterial infection blocks the appearance of sickness behaviors. Collectively, these data are consistent with the notion that the immune system communicates with the brain to regulate behavior in a way that is consistent with animal survival.
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Affiliation(s)
- Robert H McCusker
- Integrative Immunology and Behavior Program, Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801-3873, USA.
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14
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McFarlane D, Wolf RF, McDaniel KA, White GL. The effect of season on inflammatory response in captive baboons. J Med Primatol 2012; 41:341-8. [PMID: 22905903 DOI: 10.1111/j.1600-0684.2012.00560.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2012] [Indexed: 12/27/2022]
Abstract
INTRODUCTION Highly seasonal animals demonstrate predictable changes in immune function that coincide with changes in photoperiod. Little is known about the effect of season on immune response in baboons. The objective of this study was to determine the effect of season on inflammatory response in baboons. MATERIALS AND METHODS Peripheral blood mononuclear cell cytokine response following immune stimulation and serum markers of inflammation were assessed during each season in two groups of young male baboons: one housed under natural light and one in a controlled environment of 12 hours light:12 hours dark. RESULTS A seasonal immune rhythm was evident in both groups, with a greater TNF-α and IL-6 response to stimulation and serum CRP concentration in June and September compared with December. CONCLUSIONS Season is an important experimental confounder, and therefore, time of year should be controlled when designing studies and analyzing data from immune studies in baboons.
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Affiliation(s)
- Dianne McFarlane
- Department of Physiological Sciences, Center of Veterinary Health Sciences, Oklahoma State University, Stillwater, OK, USA.
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15
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Prendergast BJ. Can photoperiod predict mortality in the 1918-1920 influenza pandemic? J Biol Rhythms 2011; 26:345-52. [PMID: 21775293 DOI: 10.1177/0748730411409708] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Amplitude of the seasonal change in day length increases with distance from the equator, and changes in day length markedly alter immune function in diverse nonhuman animal models of infection. Historical records of mortality data, ambient temperature, population density, geography, and economic indicators from 42 countries during 1918-1920 were analyzed to determine relative contributions toward human mortality during the "Spanish" influenza pandemic of 1918-1920. The data identify a strong negative relation between distance from the equator and mortality during the 1918-1920 influenza pandemic, which, in a multiple regression model, manifested independent of major economic, demographic, and temperature variables. Enhanced survival was evident in populations that experienced a winter nadir day length ≤10 h light/day, relative to those that experienced lower amplitude changes in photoperiod. Numerous reports indicate that exposure to short day lengths, typical of those occurring outside the tropics during winter, yields robust and enduring reductions in the magnitude of cytokine, febrile, and behavioral responses to infection. The present results are preliminary but prompt the conjecture that, if similar mechanisms are operant in humans, then they would be predicted to mitigate symptoms of infection in proportion to an individual's distance from the equator. Although limitations and uncertainties accompany regression-based analyses of historical epidemiological data, latitude, per se, may be an underrecognized factor in mortality during the 1918-1920 influenza pandemic. The author proposes that some proportion of the global variance in morbidity and mortality from infectious diseases may be explained by effects of day length on the innate immune response to infection.
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Affiliation(s)
- Brian J Prendergast
- Department of Psychology, Institute for Mind and Biology, University of Chicago, Chicago, IL 60637, USA.
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16
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Castro R, Angus DC, Rosengart MR. The effect of light on critical illness. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2011; 15:218. [PMID: 21457502 PMCID: PMC3219304 DOI: 10.1186/cc10000] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- Ricardo Castro
- Department of Critical Care Medicine,University of Pittsburgh Medical Center, CRISMA Center, Pittsburgh, PA 15261, USA.
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17
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Schwanz L, Warner DA, McGaugh S, Di Terlizzi R, Bronikowski A. State-dependent physiological maintenance in a long-lived ectotherm, the painted turtle (Chrysemys picta). J Exp Biol 2011; 214:88-97. [DOI: 10.1242/jeb.046813] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
SUMMARY
Energy allocation among somatic maintenance, reproduction and growth varies not only among species, but among individuals according to states such as age, sex and season. Little research has been conducted on the somatic (physiological) maintenance of long-lived organisms, particularly ectotherms such as reptiles. In this study, we examined sex differences and age- and season-related variation in immune function and DNA repair efficiency in a long-lived reptile, the painted turtle (Chrysemys picta). Immune components tended to be depressed during hibernation, in winter, compared with autumn or spring. Increased heterophil count during hibernation provided the only support for winter immunoenhancement. In juvenile and adult turtles, we found little evidence for senescence in physiological maintenance, consistent with predictions for long-lived organisms. Among immune components, swelling in response to phytohemagglutinin (PHA) and control injection increased with age, whereas basophil count decreased with age. Hatchling turtles had reduced basophil counts and natural antibodies, indicative of an immature immune system, but demonstrated higher DNA repair efficiency than older turtles. Reproductively mature turtles had reduced lymphocytes compared with juvenile turtles in the spring, presumably driven by a trade-off between maintenance and reproduction. Sex had little influence on physiological maintenance. These results suggest that components of physiological maintenance are modulated differentially according to individual state and highlight the need for more research on the multiple components of physiological maintenance in animals of variable states.
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Affiliation(s)
- Lisa Schwanz
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA 50011, USA
- School of Marine and Tropical Biology, James Cook University, Townsville, QLD 4811, Australia
| | - Daniel A. Warner
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA 50011, USA
| | - Suzanne McGaugh
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA 50011, USA
| | - Roberta Di Terlizzi
- College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
- School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Anne Bronikowski
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA 50011, USA
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18
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Olson AL, Swigris JJ, Raghu G, Brown KK. Seasonal variation: mortality from pulmonary fibrosis is greatest in the winter. Chest 2009; 136:16-22. [PMID: 18689582 PMCID: PMC3662208 DOI: 10.1378/chest.08-0703] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Accepted: 07/16/2008] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND In the general population, rates of certain respiratory infections (and mortality from these infections) are higher in winter. We hypothesized that in patients with idiopathic pulmonary fibrosis (IPF) and/or pulmonary fibrosis (PF) from any cause, death rates would be increased during the winter season, independent of recognized infection. Our objective was to determine if mortality rates from IPF and/or PF of any cause exhibit seasonal variation. METHODS Using death records from the National Center for Health Statistics, we calculated monthly mortality rates for persons with PF and developed a multivariable model to determine if these mortality rates exhibited seasonal variation. RESULTS From spring of 1992 to fall of 2003, there were 27,367,580 deaths in the United States and 170,984 decedents with PF. The average mortality rate among all persons with PF was 17.1% higher in winter (p < 0.0001), 12.7% higher in spring (p < 0.0001), and 5.2% higher in fall (p = 0.0002) than in summer months. These findings persisted when records with a diagnostic code for pneumonia were excluded from the analysis as well as when only records in which PF was the underlying cause of death were included in the analysis. CONCLUSIONS Mortality rates from PF exhibit significant seasonal variation, with the highest rates occurring in the winter, even when recognized infection is excluded. Further studies are necessary to determine if this seasonal variation exists in a prospective cohort and, if so, to uncover its etiology.
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Affiliation(s)
- Amy L Olson
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Health Sciences Center, Denver, CO.
| | - Jeffrey J Swigris
- Interstitial Lung Disease Division, National Jewish Medical and Research Center, Denver, CO
| | - Ganesh Raghu
- Division of Pulmonary and Critical Care Medicine, University of Washington Medical Center, Seattle, WA
| | - Kevin K Brown
- Interstitial Lung Disease Division, National Jewish Medical and Research Center, Denver, CO
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19
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Prendergast BJ, Galang J, Kay LM, Pyter LM. Influence of the olfactory bulbs on blood leukocytes and behavioral responses to infection in Siberian hamsters. Brain Res 2009; 1268:48-57. [PMID: 19368847 DOI: 10.1016/j.brainres.2009.01.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Revised: 01/12/2009] [Accepted: 01/14/2009] [Indexed: 10/21/2022]
Abstract
Surgical removal of the olfactory bulb alters several aspects of immunological activity. This study investigated the role of the olfactory bulbs in the control of behavioral responses to simulated infection, and the environmental modulation of sickness behaviors by changes in day length. Adult male Siberian hamsters (Phodopus sungorus) were subjected to bilateral olfactory bulbectomy (OBx) or a sham surgical procedure, and were then exposed to long(15 h light/day; LD) or short (9 h light/day; SD) photoperiods for 8–12 weeks, after which circulating leukocytes and behavioral responses (anorexia, anhedonia, cachexia) to simulated gram-negative bacterial infections (i.p. lipopolysaccharide [LPS] treatment;0.625 mg/kg) were quantified. OBx treatment altered the effects of photoperiod on immune function in a trait-specific manner. LPS-induced anorexia was exacerbated in SD-OBx hamsters; LPS-induced anhedonia was exacerbated in LD-OBx hamsters; and photoperiodic differences in circulating leukocytes and LPS-induced cachexia were eliminated by OBx. Plasma cortisol concentrations did not differ between LD and SD hamsters, irrespective of olfactory bulb integrity. The data indicate that photoperiod affects immune function via OB-dependent and -independent mechanisms, and that changes in cortisol production are not required for photoperiodic changes in sickness behaviors to manifest.
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Affiliation(s)
- Brian J Prendergast
- Department of Psychology, Institute for Mind and Biology, The University of Chicago, Chicago, IL 60637, USA; Committee on Neurobiology, The University of Chicago, Chicago, IL 60637, USA.
| | - Jerome Galang
- Department of Psychology, Institute for Mind and Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Leslie M Kay
- Department of Psychology, Institute for Mind and Biology, The University of Chicago, Chicago, IL 60637, USA; Committee on Neurobiology, The University of Chicago, Chicago, IL 60637, USA
| | - Leah M Pyter
- Department of Psychology, Institute for Mind and Biology, The University of Chicago, Chicago, IL 60637, USA
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