Microglia Are Necessary to Regulate Sleep after an Immune Challenge
Microglia play a critical role in the neuroimmune response, but little is known about the role of microglia in sleep following an inflammatory trigger. Nevertheless, decades of research have been predicated on the assumption that an inflammatory trigger increases sleep through microglial activation....
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-08-01
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| Series: | Biology |
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| Online Access: | https://www.mdpi.com/2079-7737/11/8/1241 |
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| author | Rachel K. Rowe Tabitha R. F. Green Katherine R. Giordano J. Bryce Ortiz Sean M. Murphy Mark R. Opp |
| author_facet | Rachel K. Rowe Tabitha R. F. Green Katherine R. Giordano J. Bryce Ortiz Sean M. Murphy Mark R. Opp |
| author_sort | Rachel K. Rowe |
| collection | DOAJ |
| description | Microglia play a critical role in the neuroimmune response, but little is known about the role of microglia in sleep following an inflammatory trigger. Nevertheless, decades of research have been predicated on the assumption that an inflammatory trigger increases sleep through microglial activation. We hypothesized that mice (<i>n</i> = 30) with depleted microglia using PLX5622 (PLX) would sleep less following the administration of lipopolysaccharide (LPS) to induce inflammation. Brains were collected and microglial morphology was assessed using quantitative skeletal analyses and physiological parameters were recorded using non-invasive piezoelectric cages. Mice fed PLX diet had a transient increase in sleep that dissipated by week 2. Subsequently, following a first LPS injection (0.4 mg/kg), mice with depleted microglia slept more than mice on the control diet. All mice were returned to normal rodent chow to repopulate microglia in the PLX group (10 days). Nominal differences in sleep existed during the microglia repopulation period. However, following a second LPS injection, mice with repopulated microglia slept similarly to control mice during the dark period but with longer bouts during the light period. Comparing sleep after the first LPS injection to sleep after the second LPS injection, controls exhibited temporal changes in sleep patterns but no change in cumulative minutes slept, whereas cumulative sleep in mice with repopulated microglia decreased during the dark period across all days. Repopulated microglia had a reactive morphology. We conclude that microglia are necessary to regulate sleep after an immune challenge. |
| first_indexed | 2024-03-09T10:00:57Z |
| format | Article |
| id | doaj.art-f3ec24e27bd94f018a804927b7587dad |
| institution | Directory Open Access Journal |
| issn | 2079-7737 |
| language | English |
| last_indexed | 2024-03-09T10:00:57Z |
| publishDate | 2022-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Biology |
| spelling | doaj.art-f3ec24e27bd94f018a804927b7587dad2023-12-01T23:26:41ZengMDPI AGBiology2079-77372022-08-01118124110.3390/biology11081241Microglia Are Necessary to Regulate Sleep after an Immune ChallengeRachel K. Rowe0Tabitha R. F. Green1Katherine R. Giordano2J. Bryce Ortiz3Sean M. Murphy4Mark R. Opp5Department of Integrative Physiology, University of Colorado, Boulder, CO 80301, USADepartment of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ 85004, USADepartment of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ 85004, USADepartment of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ 85004, USADepartment of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ 85004, USADepartment of Integrative Physiology, University of Colorado, Boulder, CO 80301, USAMicroglia play a critical role in the neuroimmune response, but little is known about the role of microglia in sleep following an inflammatory trigger. Nevertheless, decades of research have been predicated on the assumption that an inflammatory trigger increases sleep through microglial activation. We hypothesized that mice (<i>n</i> = 30) with depleted microglia using PLX5622 (PLX) would sleep less following the administration of lipopolysaccharide (LPS) to induce inflammation. Brains were collected and microglial morphology was assessed using quantitative skeletal analyses and physiological parameters were recorded using non-invasive piezoelectric cages. Mice fed PLX diet had a transient increase in sleep that dissipated by week 2. Subsequently, following a first LPS injection (0.4 mg/kg), mice with depleted microglia slept more than mice on the control diet. All mice were returned to normal rodent chow to repopulate microglia in the PLX group (10 days). Nominal differences in sleep existed during the microglia repopulation period. However, following a second LPS injection, mice with repopulated microglia slept similarly to control mice during the dark period but with longer bouts during the light period. Comparing sleep after the first LPS injection to sleep after the second LPS injection, controls exhibited temporal changes in sleep patterns but no change in cumulative minutes slept, whereas cumulative sleep in mice with repopulated microglia decreased during the dark period across all days. Repopulated microglia had a reactive morphology. We conclude that microglia are necessary to regulate sleep after an immune challenge.https://www.mdpi.com/2079-7737/11/8/1241gliainflammationsleep–wake disturbancesmicroglia depletionplx5622 |
| spellingShingle | Rachel K. Rowe Tabitha R. F. Green Katherine R. Giordano J. Bryce Ortiz Sean M. Murphy Mark R. Opp Microglia Are Necessary to Regulate Sleep after an Immune Challenge Biology glia inflammation sleep–wake disturbances microglia depletion plx5622 |
| title | Microglia Are Necessary to Regulate Sleep after an Immune Challenge |
| title_full | Microglia Are Necessary to Regulate Sleep after an Immune Challenge |
| title_fullStr | Microglia Are Necessary to Regulate Sleep after an Immune Challenge |
| title_full_unstemmed | Microglia Are Necessary to Regulate Sleep after an Immune Challenge |
| title_short | Microglia Are Necessary to Regulate Sleep after an Immune Challenge |
| title_sort | microglia are necessary to regulate sleep after an immune challenge |
| topic | glia inflammation sleep–wake disturbances microglia depletion plx5622 |
| url | https://www.mdpi.com/2079-7737/11/8/1241 |
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