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McKee CA, Polino AJ, King MW, Musiek ES. Circadian clock protein BMAL1 broadly influences autophagy and endolysosomal function in astrocytes. Proc Natl Acad Sci U S A 2023; 120:e2220551120. [PMID: 37155839 PMCID: PMC10194014 DOI: 10.1073/pnas.2220551120] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [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: 12/02/2022] [Accepted: 04/12/2023] [Indexed: 05/10/2023] Open
Abstract
An emerging role for the circadian clock in autophagy and lysosome function has opened new avenues for exploration in the field of neurodegeneration. The daily rhythms of circadian clock proteins may coordinate gene expression programs involved not only in daily rhythms but in many cellular processes. In the brain, astrocytes are critical for sensing and responding to extracellular cues to support neurons. The core clock protein BMAL1 serves as the primary positive circadian transcriptional regulator and its depletion in astrocytes not only disrupts circadian function but also leads to a unique cell-autonomous activation phenotype. We report here that astrocyte-specific deletion of Bmal1 influences endolysosome function, autophagy, and protein degradation dynamics. In vitro, Bmal1-deficient astrocytes exhibit increased endocytosis, lysosome-dependent protein cleavage, and accumulation of LAMP1- and RAB7-positive organelles. In vivo, astrocyte-specific Bmal1 knockout (aKO) brains show accumulation of autophagosome-like structures within astrocytes by electron microscopy. Transcriptional analysis of isolated astrocytes from young and aged Bmal1 aKO mice indicates broad dysregulation of pathways involved in lysosome function which occur independently of TFEB activation. Since a clear link has been established between neurodegeneration and endolysosome dysfunction over the course of aging, this work implicates BMAL1 as a key regulator of these crucial astrocyte functions in health and disease.
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Affiliation(s)
- Celia A. McKee
- Department of Neurology, Washington University School of Medicine in St. Louis, St. Louis, MO63110
- Center on Biological Rhythms and Sleep, Washington University School of Medicine in St. Louis, St. Louis, MO63110
| | - Alexander J. Polino
- Department of Cell Biology and Physiology, Washington University School of Medicine in St. Louis, St. Louis, MO63110
| | - Melvin W. King
- Department of Neurology, Washington University School of Medicine in St. Louis, St. Louis, MO63110
- Center on Biological Rhythms and Sleep, Washington University School of Medicine in St. Louis, St. Louis, MO63110
| | - Erik S. Musiek
- Department of Neurology, Washington University School of Medicine in St. Louis, St. Louis, MO63110
- Center on Biological Rhythms and Sleep, Washington University School of Medicine in St. Louis, St. Louis, MO63110
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2
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McKee CA, Lee J, Cai Y, Saito T, Saido T, Musiek ES. Astrocytes deficient in circadian clock gene Bmal1 show enhanced activation responses to amyloid-beta pathology without changing plaque burden. Sci Rep 2022; 12:1796. [PMID: 35110643 PMCID: PMC8810760 DOI: 10.1038/s41598-022-05862-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 01/06/2022] [Indexed: 12/15/2022] Open
Abstract
An emerging link between circadian clock function and neurodegeneration has indicated a critical role for the molecular clock in brain health. We previously reported that deletion of the core circadian clock gene Bmal1 abrogates clock function and induces cell-autonomous astrocyte activation. Regulation of astrocyte activation has important implications for protein aggregation, inflammation, and neuronal survival in neurodegenerative conditions such as Alzheimer's disease (AD). Here, we investigated how astrocyte activation induced by Bmal1 deletion regulates astrocyte gene expression, amyloid-beta (Aβ) plaque-associated activation, and plaque deposition. To address these questions, we crossed astrocyte-specific Bmal1 knockout mice (Aldh1l1-CreERT2;Bmal1fl/fl, termed BMAL1 aKO), to the APP/PS1-21 and the APPNL-G-F models of Aβ accumulation. Transcriptomic profiling showed that BMAL1 aKO induced a unique transcriptional profile affecting genes involved in both the generation and elimination of Aβ. BMAL1 aKO mice showed exacerbated astrocyte activation around Aβ plaques and altered gene expression. However, this astrogliosis did not affect plaque accumulation or neuronal dystrophy in either model. Our results demonstrate that the striking astrocyte activation induced by Bmal1 knockout does not influence Aβ deposition, which indicates that the effect of astrocyte activation on plaque pathology in general is highly dependent on the molecular mechanism of activation.
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Affiliation(s)
- Celia A McKee
- Department of Neurology and Center On Biological Rhythms And Sleep, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
| | - Jiyeon Lee
- Department of Neurology and Center On Biological Rhythms And Sleep, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
| | - Yuqi Cai
- Department of Neurology and Center On Biological Rhythms And Sleep, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Takashi Saito
- Department of Neurocognitive Science, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan
| | - Takaomi Saido
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, Wako-shi, Saitama, Japan
| | - Erik S Musiek
- Department of Neurology and Center On Biological Rhythms And Sleep, Washington University in St. Louis School of Medicine, St. Louis, MO, USA.
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3
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Lananna BV, McKee CA, King MW, Del-Aguila JL, Dimitry JM, Farias FHG, Nadarajah CJ, Xiong DD, Guo C, Cammack AJ, Elias JA, Zhang J, Cruchaga C, Musiek ES. Chi3l1/YKL-40 is controlled by the astrocyte circadian clock and regulates neuroinflammation and Alzheimer's disease pathogenesis. Sci Transl Med 2021; 12:12/574/eaax3519. [PMID: 33328329 DOI: 10.1126/scitranslmed.aax3519] [Citation(s) in RCA: 86] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 04/21/2020] [Accepted: 08/29/2020] [Indexed: 12/12/2022]
Abstract
Regulation of glial activation and neuroinflammation are critical factors in the pathogenesis of Alzheimer's disease (AD). YKL-40, a primarily astrocytic protein encoded by the gene Chi3l1, is a widely studied cerebrospinal fluid biomarker that increases with aging and early in AD. However, the function of Chi3l1/YKL-40 in AD is unknown. In a cohort of patients with AD, we observed that a variant in the human CHI3L1 gene, which results in decreased CSF YKL-40 expression, was associated with slower AD progression. At baseline, Chi3l1 deletion in mice had no effect on astrocyte activation while modestly promoting microglial activation. In a mouse APP/PS1 model of AD, Chi3l1 deletion decreased amyloid plaque burden and increased periplaque expression of the microglial lysosomal marker CD68, suggesting that Chi3l1 may suppress glial phagocytic activation and promote amyloid accumulation. Accordingly, Chi3l1 knockdown increased phagocytosis of zymosan particles and of β-amyloid peptide in both astrocytes and microglia in vitro. We further observed that expression of Chi3l1 is regulated by the circadian clock, as deletion of the core clock proteins BMAL1 or CLOCK/NPAS2 strongly suppresses basal Chi3l1 expression, whereas deletion of the negative clock regulators PER1/PER2 increased Chi3l1 expression. Basal Chi3l1 mRNA was nonrhythmic because of a long mRNA half-life in astrocytes. However, inflammatory induction of Chi3l1 was gated by the clock. Our findings reveal Chi3l1/YKL-40 as a modulator of glial phagocytic activation and AD pathogenesis in both mice and humans and suggest that the astrocyte circadian clock regulates inflammatory Chi3l1 induction.
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Affiliation(s)
- Brian V Lananna
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Celia A McKee
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Melvin W King
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jorge L Del-Aguila
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Julie M Dimitry
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Fabiana H G Farias
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Collin J Nadarajah
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - David D Xiong
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Chun Guo
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Alexander J Cammack
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jack A Elias
- Division of Medicine and Biological Sciences, Brown University, Providence, RI 02903, USA
| | - Jinsong Zhang
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Carlos Cruchaga
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA.,Knight Alzheimer's Disease Research Center and Hope Center for Neurological Disease, Washington University School of Medicine, St. Louis, MO 63108, USA
| | - Erik S Musiek
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA. .,Knight Alzheimer's Disease Research Center and Hope Center for Neurological Disease, Washington University School of Medicine, St. Louis, MO 63108, USA
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4
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Bolte AC, Dutta AB, Hurt ME, Smirnov I, Kovacs MA, McKee CA, Ennerfelt HE, Shapiro D, Nguyen BH, Frost EL, Lammert CR, Kipnis J, Lukens JR. Meningeal lymphatic dysfunction exacerbates traumatic brain injury pathogenesis. Nat Commun 2020; 11:4524. [PMID: 32913280 PMCID: PMC7483525 DOI: 10.1038/s41467-020-18113-4] [Citation(s) in RCA: 156] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 08/06/2020] [Indexed: 01/12/2023] Open
Abstract
Traumatic brain injury (TBI) is a leading global cause of death and disability. Here we demonstrate in an experimental mouse model of TBI that mild forms of brain trauma cause severe deficits in meningeal lymphatic drainage that begin within hours and last out to at least one month post-injury. To investigate a mechanism underlying impaired lymphatic function in TBI, we examined how increased intracranial pressure (ICP) influences the meningeal lymphatics. We demonstrate that increased ICP can contribute to meningeal lymphatic dysfunction. Moreover, we show that pre-existing lymphatic dysfunction before TBI leads to increased neuroinflammation and negative cognitive outcomes. Finally, we report that rejuvenation of meningeal lymphatic drainage function in aged mice can ameliorate TBI-induced gliosis. These findings provide insights into both the causes and consequences of meningeal lymphatic dysfunction in TBI and suggest that therapeutics targeting the meningeal lymphatic system may offer strategies to treat TBI.
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Affiliation(s)
- Ashley C Bolte
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908, USA
- Medical Scientist Training Program, University of Virginia, Charlottesville, VA, 22908, USA
- Immunology Training Program, University of Virginia, Charlottesville, VA, 22908, USA
| | - Arun B Dutta
- Medical Scientist Training Program, University of Virginia, Charlottesville, VA, 22908, USA
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, 22908, USA
| | - Mariah E Hurt
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
| | - Igor Smirnov
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
| | - Michael A Kovacs
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908, USA
- Medical Scientist Training Program, University of Virginia, Charlottesville, VA, 22908, USA
- Immunology Training Program, University of Virginia, Charlottesville, VA, 22908, USA
| | - Celia A McKee
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
| | - Hannah E Ennerfelt
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, 22908, USA
| | - Daniel Shapiro
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
| | - Bao H Nguyen
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, 22908, USA
| | - Elizabeth L Frost
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
| | - Catherine R Lammert
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, 22908, USA
| | - Jonathan Kipnis
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, 22908, USA
| | - John R Lukens
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA.
- Medical Scientist Training Program, University of Virginia, Charlottesville, VA, 22908, USA.
- Immunology Training Program, University of Virginia, Charlottesville, VA, 22908, USA.
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, 22908, USA.
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5
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Bolte AC, Hurt ME, Smirnov I, Dutta AB, Kovacs MA, McKee CA, Natale N, Ennerfelt HE, Nguyen BH, Frost EL, Lammert CE, Kipnis J, Lukens JR. Meningeal lymphatic dysfunction exacerbates traumatic brain injury pathogenesis. The Journal of Immunology 2020. [DOI: 10.4049/jimmunol.204.supp.64.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Traumatic brain injury (TBI) has emerged as a leading cause of death and disability. Despite being a growing medical issue, the biological factors that promote central nervous system (CNS) pathology and neurological dysfunction following TBI remain poorly characterized. Recently, the meningeal lymphatic system was identified as a critical mediator of drainage from the CNS. In comparison to other peripheral organs, our understanding of how defects in lymphatic drainage from the CNS contribute to disease is limited. It is still unknown how TBI impacts meningeal lymphatic function and whether disruptions in this drainage pathway are involved in driving TBI pathogenesis. Here we demonstrate that even mild forms of brain trauma cause severe deficits in meningeal lymphatic drainage that can last out to at least two weeks post-injury. To investigate a mechanism behind impaired lymphatic function in TBI, we examined how increased intracranial pressure (ICP) influences the meningeal lymphatics, as increased ICP commonly occurs in TBI. We demonstrate that increased ICP is capable of provoking meningeal lymphatic dysfunction. Moreover, we show that pre-existing lymphatic dysfunction mediated by targeted photoablation before TBI leads to increased neuroinflammation and cognitive deficits. These findings provide new insights into both the causes and consequences of meningeal lymphatic dysfunction in TBI and suggest that therapeutics targeting the meningeal lymphatic system may offer strategies to treat TBI.
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McKee CA, Lananna BV, Musiek ES. Circadian regulation of astrocyte function: implications for Alzheimer's disease. Cell Mol Life Sci 2020; 77:1049-1058. [PMID: 31578625 PMCID: PMC7098845 DOI: 10.1007/s00018-019-03314-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [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: 04/17/2019] [Revised: 08/26/2019] [Accepted: 09/19/2019] [Indexed: 12/13/2022]
Abstract
The circadian clock regulates rhythms in gene transcription that have a profound impact on cellular function, behavior, and disease. Circadian dysfunction is a symptom of aging and neurodegenerative diseases, and recent studies suggest a bidirectional relationship between impaired clock function and neurodegeneration. Glial cells possess functional circadian clocks which may serve to control glial responses to daily oscillations in brain activity, cellular stress, and metabolism. Astrocytes directly support brain function through synaptic interactions, neuronal metabolic support, neuroinflammatory regulation, and control of neurovascular coupling at blood and CSF barriers. Emerging evidence suggests that the astrocyte circadian clock may be involved in many of these processes, and that clock disruption could influence neurodegeneration by disrupting several aspects of astrocyte function. Here we review the literature surrounding circadian control of astrocyte function in health and disease, and discuss the potential implications of astrocyte clocks for neurodegeneration.
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Affiliation(s)
- Celia A McKee
- Department of Neurology, Washington University School of Medicine, Box 8111, 425 S. Euclid Ave, St. Louis, MO, 63105, USA
| | - Brian V Lananna
- Department of Neurology, Washington University School of Medicine, Box 8111, 425 S. Euclid Ave, St. Louis, MO, 63105, USA
| | - Erik S Musiek
- Department of Neurology, Washington University School of Medicine, Box 8111, 425 S. Euclid Ave, St. Louis, MO, 63105, USA.
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Patel TK, Habimana-Griffin L, Gao X, Xu B, Achilefu S, Alitalo K, McKee CA, Sheehan PW, Musiek ES, Xiong C, Coble D, Holtzman DM. Dural lymphatics regulate clearance of extracellular tau from the CNS. Mol Neurodegener 2019; 14:11. [PMID: 30813965 PMCID: PMC6391770 DOI: 10.1186/s13024-019-0312-x] [Citation(s) in RCA: 120] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 02/20/2019] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Alzheimer's disease is characterized by two main neuropathological hallmarks: extracellular plaques of amyloid-β (Aβ) protein and intracellular aggregates of tau protein. Although tau is normally a soluble monomer that bind microtubules, in disease it forms insoluble, hyperphosphorylated aggregates in the cell body. Aside from its role in AD, tau is also involved in several other neurodegenerative disorders collectively called tauopathies, such as progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), some forms of frontotemporal dementia, and argyrophilic grain disease (AGD). The prion hypothesis suggests that after an initial trigger event, misfolded forms of tau are released into the extracellular space, where they spread through different brain regions, enter cells, and seeding previously normal forms. Thus understanding mechanisms regulating the clearance of extracellular tau from the CNS is important. The discovery of a true lymphatic system in the dura and its potential role in mediating Aβ pathology prompted us to investigate its role in regulating extracellular tau clearance. METHODS To study clearance of extracellular tau from the brain, we conjugated monomeric human tau with a near-infrared dye cypate, and injected this labeled tau in the parenchyma of both wild-type and K14-VEGFR3-Ig transgenic mice, which lack a functional CNS lymphatic system. Following injection we performed longitudinal imaging using fluorescence molecular tomography (FMT) and quantified fluorescence to calculate clearance of tau from the brain. To complement this, we also measured tau clearance to the periphery by measuring plasma tau in both groups of mice. RESULTS Our results show that a significantly higher amount of tau is retained in the brains of K14-VEGFR3-Ig vs. wild type mice at 48 and 72 h post-injection and its subsequent clearance to the periphery is delayed. We found that clearance of reference tracer human serum albumin (HSA) was also significantly delayed in the K14-VEGFR3-Ig mice. CONCLUSIONS The dural lymphatic system appears to play an important role in clearance of extracellular tau, since tau clearance is impaired in the absence of functional lymphatics. Based on our baseline characterization of extracellular tau clearance, future studies are warranted to look at the interaction between tau pathology and efficiency of lymphatic function.
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Affiliation(s)
- Tirth K. Patel
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer’s Disease Research Center, Washington University in St. Louis, St. Louis, MO 63110 USA
| | | | - Xuefeng Gao
- Department of Radiology, Washington University, St. Louis, MO 63110 USA
| | - Baogang Xu
- Department of Radiology, Washington University, St. Louis, MO 63110 USA
| | - Samuel Achilefu
- Department of Radiology, Washington University, St. Louis, MO 63110 USA
- Department of Biochemistry and Molecular Biophysics, Department of Biomedical Engineering, Washington University, St. Louis, MO 63110 USA
| | - Kari Alitalo
- Wihuri Research Institute and Translational Cancer Biology Program, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Celia A. McKee
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer’s Disease Research Center, Washington University in St. Louis, St. Louis, MO 63110 USA
| | - Patrick W. Sheehan
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer’s Disease Research Center, Washington University in St. Louis, St. Louis, MO 63110 USA
| | - Erik S. Musiek
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer’s Disease Research Center, Washington University in St. Louis, St. Louis, MO 63110 USA
| | - Chengjie Xiong
- Division of Biostatistics, Knight Alzheimer’s Disease Research Center, Washington University, St. Louis, MO 63110 USA
| | - Dean Coble
- Division of Biostatistics, Knight Alzheimer’s Disease Research Center, Washington University, St. Louis, MO 63110 USA
| | - David M. Holtzman
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer’s Disease Research Center, Washington University in St. Louis, St. Louis, MO 63110 USA
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Lananna BV, Nadarajah CJ, Izumo M, Cedeño MR, Xiong DD, Dimitry J, Tso CF, McKee CA, Griffin P, Sheehan PW, Haspel JA, Barres BA, Liddelow SA, Takahashi JS, Karatsoreos IN, Musiek ES. Cell-Autonomous Regulation of Astrocyte Activation by the Circadian Clock Protein BMAL1. Cell Rep 2018; 25:1-9.e5. [PMID: 30282019 PMCID: PMC6221830 DOI: 10.1016/j.celrep.2018.09.015] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [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: 09/15/2017] [Revised: 08/14/2018] [Accepted: 09/06/2018] [Indexed: 01/14/2023] Open
Abstract
Circadian clock dysfunction is a common symptom of aging and neurodegenerative diseases, though its impact on brain health is poorly understood. Astrocyte activation occurs in response to diverse insults and plays a critical role in brain health and disease. We report that the core circadian clock protein BMAL1 regulates astrogliosis in a synergistic manner via a cell-autonomous mechanism and a lesser non-cell-autonomous signal from neurons. Astrocyte-specific Bmal1 deletion induces astrocyte activation and inflammatory gene expression in vitro and in vivo, mediated in part by suppression of glutathione-S-transferase signaling. Functionally, loss of Bmal1 in astrocytes promotes neuronal death in vitro. Our results demonstrate that the core clock protein BMAL1 regulates astrocyte activation and function in vivo, elucidating a mechanism by which the circadian clock could influence many aspects of brain function and neurological disease.
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Affiliation(s)
- Brian V Lananna
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Collin J Nadarajah
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Mariko Izumo
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Michelle R Cedeño
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - David D Xiong
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Julie Dimitry
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Chak Foon Tso
- Department of Biology, Washington University, St. Louis, MO, USA
| | - Celia A McKee
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Percy Griffin
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Patrick W Sheehan
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Jeffery A Haspel
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Ben A Barres
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Shane A Liddelow
- Neuroscience Institute, Department of Neuroscience and Physiology, NYU Langone Medical Center, New York, NY, USA; Department of Pharmacology and Therapeutics, University of Melbourne, Melbourne, VIC, Australia
| | - Joseph S Takahashi
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA; Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ilia N Karatsoreos
- Integrative Physiology and Neuroscience, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
| | - Erik S Musiek
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA.
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Abstract
Traumatic brain injury (TBI) affects an ever-growing population of all ages with long-term consequences on health and cognition. Many of the issues that TBI patients face are thought to be mediated by the immune system. Primary brain damage that occurs at the time of injury can be exacerbated and prolonged for months or even years by chronic inflammatory processes, which can ultimately lead to secondary cell death, neurodegeneration, and long-lasting neurological impairment. Researchers have turned to rodent models of TBI in order to understand how inflammatory cells and immunological signaling regulate the post-injury response and recovery mechanisms. In addition, the development of numerous methods to manipulate genes involved in inflammation has recently expanded the possibilities of investigating the immune response in TBI models. As results from these studies accumulate, scientists have started to link cells and signaling pathways to pro- and anti-inflammatory processes that may contribute beneficial or detrimental effects to the injured brain. Moreover, emerging data suggest that targeting aspects of the immune response may offer promising strategies to treat TBI. This review will cover insights gained from studies that approach TBI research from an immunological perspective and will summarize our current understanding of the involvement of specific immune cell types and cytokines in TBI pathogenesis.
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Affiliation(s)
- Celia A McKee
- Department of Neuroscience, Center for Brain Immunology and Glia, School of Medicine, University of Virginia , Charlottesville, VA , USA
| | - John R Lukens
- Department of Neuroscience, Center for Brain Immunology and Glia, School of Medicine, University of Virginia , Charlottesville, VA , USA
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10
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Abstract
Traumatic brain injury (TBI) affects an ever-growing population of all ages with long-term consequences on health and cognition. Many of the issues that TBI patients face are thought to be mediated by the immune system. Primary brain damage that occurs at the time of injury can be exacerbated and prolonged for months or even years by chronic inflammatory processes, which can ultimately lead to secondary cell death, neurodegeneration, and long-lasting neurological impairment. Researchers have turned to rodent models of TBI in order to understand how inflammatory cells and immunological signaling regulate the post-injury response and recovery mechanisms. In addition, the development of numerous methods to manipulate genes involved in inflammation has recently expanded the possibilities of investigating the immune response in TBI models. As results from these studies accumulate, scientists have started to link cells and signaling pathways to pro- and anti-inflammatory processes that may contribute beneficial or detrimental effects to the injured brain. Moreover, emerging data suggest that targeting aspects of the immune response may offer promising strategies to treat TBI. This review will cover insights gained from studies that approach TBI research from an immunological perspective and will summarize our current understanding of the involvement of specific immune cell types and cytokines in TBI pathogenesis.
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Affiliation(s)
- Celia A. McKee
- Department of Neuroscience, Center for Brain Immunology and Glia, School of Medicine, University of Virginia, Charlottesville, VA, USA
| | - John R. Lukens
- Department of Neuroscience, Center for Brain Immunology and Glia, School of Medicine, University of Virginia, Charlottesville, VA, USA
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Eicher SD, McKee CA, Carroll JA, Pajor EA. Supplemental vitamin C and yeast cell wall β-glucan as growth enhancers in newborn pigs and as immunomodulators after an endotoxin challenge after weaning1. J Anim Sci 2006; 84:2352-60. [PMID: 16908637 DOI: 10.2527/jas.2005-770] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
To test possible dietary immune modulators, 32 crossbred male pigs were given 1 of 4 dietary treatments (8 pigs/treatment): control, Saccharomyces cerevisiae with beta-glucan (Energy Plus, Natural Chem Industries LTD, Houston, TX; 0.312 g/kg of BW, 2.5% of diet), vitamin C (Stay C 35, DSM Nutritional Products Inc., Prisippany, NJ; 75 ppm), or beta-glucan plus vitamin C together (combination; 0.312 g/kg of BW and 75 ppm, respectively). Supplements were given in whole milk within 36 h of birth and then daily for 2 wk until weaning, when the supplement was given in feed for an additional 2 wk. Growth was recorded during the 4 wk of supplement delivery. An i.v. lipopolysaccharide challenge (LPS; 150 microg/kg) was given 14 d postweaning at 0900. Behavior was observed, and blood samples were collected every 30 min for 4 h via a jugular catheter from -1 (0800) to 3 (1200) h relative to challenge (-60, -30, 0, 30, 60, 90, 120, 150, and 180 min), and tissues were collected after exsanguination. Beta-glucan (glucan and combination) increased (P < 0.05) BW and ADG compared with vitamin C and control. Cortisol concentrations showed an interaction (P < 0.05) of the beta-glucan and vitamin C. Intestinal expression of tumor-necrosis factor (TNF)-alpha mRNA was greatest for vitamin C and beta-glucan compared with control and combination, and liver TNF-alpha mRNA expression showed a main effect (P < 0.01) of beta-glucan. Lung expression of TNF-alpha mRNA exhibited a vitamin C effect (P < 0.01). In contrast, spleen had greater (P < 0.01) relative abundance of TNF-alpha mRNA in beta-glucan pigs. Intestinal expression of IL-1Ra mRNA was greater (P < 0.05) for vitamin C and beta-glucan treatments compared with the control and combination pigs. Liver expression of IL-1 receptor antagonist mRNA exhibited a vitamin C effect (P < 0.01). Lying and sleeping behaviors differed (P < 0.05) among treatments early in the observations (0700 to 0720), then sporadically until 50 min after the LPS injection. The vitamin C group slept less (P < 0.05) on those occasions. The time spent lying was least (P < 0.05) for the glucan and combination pigs immediately after the injection. These results show a complex interaction between vitamin C and this yeast product after LPS challenge, with differential expression in tissues by 2 h after LPS injections. The combination enhanced postweaning growth and reduced TNF-alpha expression of the intestinal and liver tissues, suggesting an important immunomodulatory role of the combination treatment.
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Affiliation(s)
- S D Eicher
- Livestock Behavior Research Unit, USDA-ARS, West Lafayette, IN 47907, USA.
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