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Abo SMC, Layton AT. Modeling the circadian regulation of the immune system: Sexually dimorphic effects of shift work. PLoS Comput Biol 2021; 17:e1008514. [PMID: 33788832 PMCID: PMC8041207 DOI: 10.1371/journal.pcbi.1008514] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 04/12/2021] [Accepted: 03/06/2021] [Indexed: 12/31/2022] Open
Abstract
The circadian clock exerts significance influence on the immune system and disruption of circadian rhythms has been linked to inflammatory pathologies. Shift workers often experience circadian misalignment as their irregular work schedules disrupt the natural light-dark cycle, which in turn can cause serious health problems associated with alterations in genetic expressions of clock genes. In particular, shift work is associated with impairment in immune function, and those alterations are sex-specific. The goal of this study is to better understand the mechanisms that explain the weakened immune system in shift workers. To achieve that goal, we have constructed a mathematical model of the mammalian pulmonary circadian clock coupled to an acute inflammation model in the male and female rats. Shift work was simulated by an 8h-phase advance of the circadian system with sex-specific modulation of clock genes. The model reproduces the clock gene expression in the lung and the immune response to various doses of lipopolysaccharide (LPS). Under normal conditions, our model predicts that a host is more sensitive to LPS at circadian time (CT) CT12 versus CT0 due to a dynamic change of Interleukin 10 (IL-10), an anti-inflammatory cytokine. We identify REV-ERB as a key modulator of IL-10 activity throughout the circadian day. The model also predicts a reversal of the times of lowest and highest sensitivity to LPS, with males and females exhibiting an exaggerated response to LPS at CT0, which is countered by a blunted immune response at CT12. Overall, females produce fewer pro-inflammatory cytokines than males, but the extent of sequelae experienced by males and females varies across the circadian day. This model can serve as an essential component in an integrative model that will yield mechanistic understanding of how shift work-mediated circadian disruptions affect the inflammatory and other physiological responses.
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Affiliation(s)
- Stéphanie M. C. Abo
- Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada
| | - Anita T. Layton
- Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada
- Department of Biology, Cheriton School of Computer Science, and School of Pharmacology, University of Waterloo, Waterloo, Ontario, Canada
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Yamakawa G, Brady R, Sun M, McDonald S, Shultz S, Mychasiuk R. The interaction of the circadian and immune system: Desynchrony as a pathological outcome to traumatic brain injury. Neurobiol Sleep Circadian Rhythms 2020; 9:100058. [PMID: 33364525 PMCID: PMC7752723 DOI: 10.1016/j.nbscr.2020.100058] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/11/2020] [Accepted: 10/07/2020] [Indexed: 12/16/2022] Open
Abstract
Traumatic brain injury (TBI) is a complex and costly worldwide phenomenon that can lead to many negative health outcomes including disrupted circadian function. There is a bidirectional relationship between the immune system and the circadian system, with mammalian coordination of physiological activities being controlled by the primary circadian pacemaker in the suprachiasmatic nucleus (SCN) of the hypothalamus. The SCN receives light information from the external environment and in turn synchronizes rhythms throughout the brain and body. The SCN is capable of endogenous self-sustained oscillatory activity through an intricate clock gene negative feedback loop. Following TBI, the response of the immune system can become prolonged and pathophysiological. This detrimental response not only occurs in the brain, but also within the periphery, where a leaky blood brain barrier can permit further infiltration of immune and inflammatory factors. The prolonged and pathological immune response that follows TBI can have deleterious effects on clock gene cycling and circadian function not only in the SCN, but also in other rhythmic areas throughout the body. This could bring about a state of circadian desynchrony where different rhythmic structures are no longer working together to promote optimal physiological function. There are many parallels between the negative symptomology associated with circadian desynchrony and TBI. This review discusses the significant contributions of an immune-disrupted circadian system on the negative symptomology following TBI. The implications of TBI symptomology as a disorder of circadian desynchrony are discussed.
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Affiliation(s)
- G.R. Yamakawa
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia
| | - R.D. Brady
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia
- Department of Medicine, University of Melbourne, Parkville, Australia
| | - M. Sun
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia
| | - S.J. McDonald
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, Australia
| | - S.R. Shultz
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia
- Department of Medicine, University of Melbourne, Parkville, Australia
| | - R. Mychasiuk
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia
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Lundy SR, Richardson S, Ramsey A, Ellerson D, Fengxia Y, Onyeabor S, Kirlin W, Thompson W, Black CM, DeBruyne JP, Davidson AJ, Immergluck LC, Blas-Machado U, Eko FO, Igietseme JU, He Q, Omosun YO. Shift work influences the outcomes of Chlamydia infection and pathogenesis. Sci Rep 2020; 10:15389. [PMID: 32958779 PMCID: PMC7505842 DOI: 10.1038/s41598-020-72409-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 08/28/2020] [Indexed: 12/16/2022] Open
Abstract
Shift work, performed by approximately 21 million Americans, is irregular or unusual work schedule hours occurring after 6:00 pm. Shift work has been shown to disrupt circadian rhythms and is associated with several adverse health outcomes and chronic diseases such as cancer, gastrointestinal and psychiatric diseases and disorders. It is unclear if shift work influences the complications associated with certain infectious agents, such as pelvic inflammatory disease, ectopic pregnancy and tubal factor infertility resulting from genital chlamydial infection. We used an Environmental circadian disruption (ECD) model mimicking circadian disruption occurring during shift work, where mice had a 6-h advance in the normal light/dark cycle (LD) every week for a month. Control group mice were housed under normal 12/12 LD cycle. Our hypothesis was that compared to controls, mice that had their circadian rhythms disrupted in this ECD model will have a higher Chlamydia load, more pathology and decreased fertility rate following Chlamydia infection. Results showed that, compared to controls, mice that had their circadian rhythms disrupted (ECD) had higher Chlamydia loads, more tissue alterations or lesions, and lower fertility rate associated with chlamydial infection. Also, infected ECD mice elicited higher proinflammatory cytokines compared to mice under normal 12/12 LD cycle. These results imply that there might be an association between shift work and the increased likelihood of developing more severe disease from Chlamydia infection.
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Affiliation(s)
- Stephanie R Lundy
- Department of Microbiology, Biochemistry & Immunology, Morehouse School of Medicine, 720 Westview Drive, S.W., Atlanta, GA, 30310, USA
| | - Shakyra Richardson
- Department of Microbiology, Biochemistry & Immunology, Morehouse School of Medicine, 720 Westview Drive, S.W., Atlanta, GA, 30310, USA
| | - Anne Ramsey
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Debra Ellerson
- Centers for Disease Control & Prevention (CDC), Atlanta, GA, 30333, USA
| | - Yan Fengxia
- Department of Community Health and Preventive Medicine, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Sunny Onyeabor
- Department of Community Health and Preventive Medicine, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Ward Kirlin
- Department of Pharmacology, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Winston Thompson
- Department of Physiology, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Carolyn M Black
- Centers for Disease Control & Prevention (CDC), Atlanta, GA, 30333, USA
| | - Jason P DeBruyne
- Department of Pharmacology, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Alec J Davidson
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Lilly C Immergluck
- Department of Microbiology, Biochemistry & Immunology, Morehouse School of Medicine, 720 Westview Drive, S.W., Atlanta, GA, 30310, USA
- Pediatric Clinical & Translational Research Unit, Clinical Research Center, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Uriel Blas-Machado
- Athens Veterinary Diagnostic Laboratory, Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, GA, 30602, USA
| | - Francis O Eko
- Department of Microbiology, Biochemistry & Immunology, Morehouse School of Medicine, 720 Westview Drive, S.W., Atlanta, GA, 30310, USA
| | - Joseph U Igietseme
- Department of Microbiology, Biochemistry & Immunology, Morehouse School of Medicine, 720 Westview Drive, S.W., Atlanta, GA, 30310, USA
- Centers for Disease Control & Prevention (CDC), Atlanta, GA, 30333, USA
| | - Qing He
- Department of Microbiology, Biochemistry & Immunology, Morehouse School of Medicine, 720 Westview Drive, S.W., Atlanta, GA, 30310, USA
- Centers for Disease Control & Prevention (CDC), Atlanta, GA, 30333, USA
| | - Yusuf O Omosun
- Department of Microbiology, Biochemistry & Immunology, Morehouse School of Medicine, 720 Westview Drive, S.W., Atlanta, GA, 30310, USA.
- Centers for Disease Control & Prevention (CDC), Atlanta, GA, 30333, USA.
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Ramsey AM, Stowie A, Castanon-Cervantes O, Davidson AJ. Environmental Circadian Disruption Increases Stroke Severity and Dysregulates Immune Response. J Biol Rhythms 2020; 35:368-376. [PMID: 32508262 DOI: 10.1177/0748730420929450.environmental] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Understanding the health consequences of chronic disruption of circadian rhythms can contribute to improving prevention strategies for shift workers. Chronic circadian disruption in shift work has been linked to a higher risk of stroke. Dysregulated immune responses are also linked to circadian disruption and may be a factor in stroke outcomes in shift workers. In this study, we test the hypotheses that specific schedules of circadian disruption exacerbate inflammatory responses in the brain, causing an increase in infarct size after experimentally induced ischemic stroke. Mice were exposed to 1 of 5 different lighting schedules followed by a 30-min middle cerebral artery occlusion, then reperfusion and 3-day recovery. A history of weekly phase advances resulted in an increased infarct volume versus the control lighting schedule. These effects were shift-direction specific, nonpermanent, and required multiple shifts to occur. In a separate cohort, stereotaxic injections of lipopolysaccharide were given bilaterally after exposure to 1 of 3 different lighting schedules. Ratios of pro- to anti-inflammatory cytokine expression show dysregulated responses after a history of phase advances. We conclude that chronic circadian disruption leads to worsened stroke outcome in a direction- and schedule-specific manner likely because of priming of the inflammatory response in the brain. These pieces of evidence suggest that the health impacts of shift work may be improved by targeting shift work scheduling, inflammatory mediators, or both.
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Affiliation(s)
- Anne M Ramsey
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia
| | - Adam Stowie
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia
| | | | - Alec J Davidson
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia
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Ramsey AM, Stowie A, Castanon-Cervantes O, Davidson AJ. Environmental Circadian Disruption Increases Stroke Severity and Dysregulates Immune Response. J Biol Rhythms 2020; 35:368-376. [PMID: 32508262 DOI: 10.1177/0748730420929450] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Understanding the health consequences of chronic disruption of circadian rhythms can contribute to improving prevention strategies for shift workers. Chronic circadian disruption in shift work has been linked to a higher risk of stroke. Dysregulated immune responses are also linked to circadian disruption and may be a factor in stroke outcomes in shift workers. In this study, we test the hypotheses that specific schedules of circadian disruption exacerbate inflammatory responses in the brain, causing an increase in infarct size after experimentally induced ischemic stroke. Mice were exposed to 1 of 5 different lighting schedules followed by a 30-min middle cerebral artery occlusion, then reperfusion and 3-day recovery. A history of weekly phase advances resulted in an increased infarct volume versus the control lighting schedule. These effects were shift-direction specific, nonpermanent, and required multiple shifts to occur. In a separate cohort, stereotaxic injections of lipopolysaccharide were given bilaterally after exposure to 1 of 3 different lighting schedules. Ratios of pro- to anti-inflammatory cytokine expression show dysregulated responses after a history of phase advances. We conclude that chronic circadian disruption leads to worsened stroke outcome in a direction- and schedule-specific manner likely because of priming of the inflammatory response in the brain. These pieces of evidence suggest that the health impacts of shift work may be improved by targeting shift work scheduling, inflammatory mediators, or both.
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Affiliation(s)
- Anne M Ramsey
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia
| | - Adam Stowie
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia
| | | | - Alec J Davidson
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia
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