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Abstract
The brain is a complex organ, fundamentally changing across the day to perform basic functions like sleep, thought, and regulating whole-body physiology. This requires a complex symphony of nutrients, hormones, ions, neurotransmitters and more to be properly distributed across the brain to maintain homeostasis throughout 24 hours. These solutes are distributed both by the blood and by cerebrospinal fluid. Cerebrospinal fluid contents are distinct from the general circulation because of regulation at brain barriers including the choroid plexus, glymphatic system, and blood-brain barrier. In this review, we discuss the overlapping circadian (≈24-hour) rhythms in brain fluid biology and at the brain barriers. Our goal is for the reader to gain both a fundamental understanding of brain barriers alongside an understanding of the interactions between these fluids and the circadian timing system. Ultimately, this review will provide new insight into how alterations in these finely tuned clocks may lead to pathology.
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Affiliation(s)
- Velia S Vizcarra
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Ryann M Fame
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Lauren M Hablitz
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
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Knudsen-Clark AM, Mwangi D, Cazarin J, Hablitz LM, Kim M, Altman BJ. Circadian rhythms of macrophages are altered by the acidic pH of the tumor microenvironment. bioRxiv 2024:2024.02.14.580339. [PMID: 38405770 PMCID: PMC10888792 DOI: 10.1101/2024.02.14.580339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Macrophages are prime therapeutic targets due to their pro-tumorigenic and immunosuppressive functions in tumors, but varying efficacy of therapeutic approaches targeting macrophages highlights our incomplete understanding of how the tumor microenvironment (TME) can influence regulation of macrophages. The circadian clock is a key internal regulator of macrophage function, but how circadian rhythms of macrophages may be influenced by the tumor microenvironment remains unknown. We found that conditions associated with the TME such as polarizing stimuli, acidic pH, and elevated lactate concentrations can each alter circadian rhythms in macrophages. Circadian rhythms were enhanced in pro-resolution macrophages but suppressed in pro-inflammatory macrophages, while acidic pH had divergent effects on circadian rhythms depending on macrophage phenotype. While cyclic AMP (cAMP) has been reported to play a role in macrophage response to acidic pH, our results indicate that pH-driven changes in circadian rhythms are not mediated solely by the cAMP signaling pathway. Remarkably, clock correlation distance analysis of tumor-associated macrophages (TAMs) revealed evidence of circadian disorder in TAMs. This is the first report providing evidence that circadian rhythms of macrophages are altered within the TME. Our data suggest that heterogeneity in circadian rhythms at the population level may underlie this circadian disorder. Finally, we sought to determine how circadian regulation of macrophages impacts tumorigenesis, and found that tumor growth was suppressed when macrophages had a functional circadian clock. Our work demonstrates a novel mechanism by which the tumor microenvironment can influence macrophage biology through altering circadian rhythms, and the contribution of circadian rhythms in macrophages to suppressing tumor growth.
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Affiliation(s)
- Amelia M. Knudsen-Clark
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, USA
| | - Daniel Mwangi
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, New York, USA
| | - Juliana Cazarin
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, New York, USA
| | - Lauren M. Hablitz
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, New York, USA
| | - Minsoo Kim
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, USA
| | - Brian J. Altman
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, New York, USA
- Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, New York, USA
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3
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Holstein-Rønsbo S, Gan Y, Giannetto MJ, Rasmussen MK, Sigurdsson B, Beinlich FRM, Rose L, Untiet V, Hablitz LM, Kelley DH, Nedergaard M. Publisher Correction: Glymphatic influx and clearance are accelerated by neurovascular coupling. Nat Neurosci 2023; 26:2036. [PMID: 37667041 DOI: 10.1038/s41593-023-01441-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2023]
Affiliation(s)
| | - Yiming Gan
- Department of Mechanical Engineering, University of Rochester Medical Center, Rochester, NY, USA
| | - Michael J Giannetto
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY, USA
| | - Martin Kaag Rasmussen
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
| | - Björn Sigurdsson
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
| | | | - Laura Rose
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
| | - Verena Untiet
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
| | - Lauren M Hablitz
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY, USA
| | - Douglas H Kelley
- Department of Mechanical Engineering, University of Rochester Medical Center, Rochester, NY, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark.
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY, USA.
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Holstein-Rønsbo S, Gan Y, Giannetto MJ, Rasmussen MK, Sigurdsson B, Beinlich FRM, Rose L, Untiet V, Hablitz LM, Kelley DH, Nedergaard M. Glymphatic influx and clearance are accelerated by neurovascular coupling. Nat Neurosci 2023; 26:1042-1053. [PMID: 37264158 PMCID: PMC10500159 DOI: 10.1038/s41593-023-01327-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Accepted: 04/12/2023] [Indexed: 06/03/2023]
Abstract
Functional hyperemia, also known as neurovascular coupling, is a phenomenon that occurs when neural activity increases local cerebral blood flow. Because all biological activity produces metabolic waste, we here sought to investigate the relationship between functional hyperemia and waste clearance via the glymphatic system. The analysis showed that whisker stimulation increased both glymphatic influx and clearance in the mouse somatosensory cortex with a 1.6-fold increase in periarterial cerebrospinal fluid (CSF) influx velocity in the activated hemisphere. Particle tracking velocimetry revealed a direct coupling between arterial dilation/constriction and periarterial CSF flow velocity. Optogenetic manipulation of vascular smooth muscle cells enhanced glymphatic influx in the absence of neural activation. We propose that impedance pumping allows arterial pulsatility to drive CSF in the same direction as blood flow, and we present a simulation that supports this idea. Thus, functional hyperemia boosts not only the supply of metabolites but also the removal of metabolic waste.
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Affiliation(s)
| | - Yiming Gan
- Department of Mechanical Engineering, University of Rochester Medical Center, Rochester, NY, USA
| | - Michael J Giannetto
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY, USA
| | - Martin Kaag Rasmussen
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
| | - Björn Sigurdsson
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
| | | | - Laura Rose
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
| | - Verena Untiet
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
| | - Lauren M Hablitz
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY, USA
| | - Douglas H Kelley
- Department of Mechanical Engineering, University of Rochester Medical Center, Rochester, NY, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark.
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY, USA.
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Gomolka RS, Hablitz LM, Mestre H, Giannetto M, Du T, Hauglund NL, Xie L, Peng W, Martinez PM, Nedergaard M, Mori Y. Loss of aquaporin-4 results in glymphatic system dysfunction via brain-wide interstitial fluid stagnation. eLife 2023; 12:82232. [PMID: 36757363 PMCID: PMC9995113 DOI: 10.7554/elife.82232] [Citation(s) in RCA: 24] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 02/08/2023] [Indexed: 02/10/2023] Open
Abstract
The glymphatic system is a fluid transport network of cerebrospinal fluid (CSF) entering the brain along arterial perivascular spaces, exchanging with interstitial fluid (ISF), ultimately establishing directional clearance of interstitial solutes. CSF transport is facilitated by the expression of aquaporin-4 (AQP4) water channels on the perivascular endfeet of astrocytes. Mice with genetic deletion of AQP4 (AQP4 KO) exhibit abnormalities in the brain structure and molecular water transport. Yet, no studies have systematically examined how these abnormalities in structure and water transport correlate with glymphatic function. Here, we used high-resolution 3D magnetic resonance (MR) non-contrast cisternography, diffusion-weighted MR imaging (MR-DWI) along with intravoxel-incoherent motion (IVIM) DWI, while evaluating glymphatic function using a standard dynamic contrast-enhanced MR imaging to better understand how water transport and glymphatic function is disrupted after genetic deletion of AQP4. AQP4 KO mice had larger interstitial spaces and total brain volumes resulting in higher water content and reduced CSF space volumes, despite similar CSF production rates and vascular density compared to wildtype mice. The larger interstitial fluid volume likely resulted in increased slow but not fast MR diffusion measures and coincided with reduced glymphatic influx. This markedly altered brain fluid transport in AQP4 KO mice may result from a reduction in glymphatic clearance, leading to enlargement and stagnation of fluid in the interstitial space. Overall, diffusion MR is a useful tool to evaluate glymphatic function and may serve as valuable translational biomarker to study glymphatics in human disease.
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Affiliation(s)
| | - Lauren M Hablitz
- Center for Translational Neuromedicine, University of Rochester Medical CenterRochesterUnited States
| | - Humberto Mestre
- Center for Translational Neuromedicine, University of Rochester Medical CenterRochesterUnited States
- Department of Neurology, University of PennsylvaniaPhiladelphiaUnited States
| | - Michael Giannetto
- Center for Translational Neuromedicine, University of Rochester Medical CenterRochesterUnited States
| | - Ting Du
- Center for Translational Neuromedicine, University of Rochester Medical CenterRochesterUnited States
- School of Pharmacy, China Medical UniversityShenyangChina
| | | | - Lulu Xie
- Center for Translational Neuromedicine, University of Rochester Medical CenterRochesterUnited States
| | - Weiguo Peng
- Center for Translational Neuromedicine, University of CopenhagenCopenhagenDenmark
- Center for Translational Neuromedicine, University of Rochester Medical CenterRochesterUnited States
| | | | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of CopenhagenCopenhagenDenmark
- Center for Translational Neuromedicine, University of Rochester Medical CenterRochesterUnited States
| | - Yuki Mori
- Center for Translational Neuromedicine, University of CopenhagenCopenhagenDenmark
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Plá V, Bork P, Harnpramukkul A, Olveda G, Ladrón-de-Guevara A, Giannetto MJ, Hussain R, Wang W, Kelley DH, Hablitz LM, Nedergaard M. A real-time in vivo clearance assay for quantification of glymphatic efflux. Cell Rep 2022; 40:111320. [PMID: 36103828 DOI: 10.1016/j.celrep.2022.111320] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 02/05/2022] [Accepted: 08/16/2022] [Indexed: 11/03/2022] Open
Abstract
Glymphatic fluid transport eliminates metabolic waste from the brain including amyloid-β, yet the methodology for studying efflux remains rudimentary. Here, we develop a method to evaluate glymphatic real-time clearance. Efflux of Direct Blue 53 (DB53, also T-1824 or Evans Blue) injected into the striatum is quantified by imaging the DB53 signal in the vascular compartment, where it is retained due to its high affinity to albumin. The DB53 signal is detectable as early as 15 min after injection and the efflux kinetics are sharply reduced in mice lacking the water channel aquaporin 4 (AQP4). Pharmacokinetic modeling reveal that DB53 efflux is consistent with the existence of two efflux paths, one with fast kinetics (T1/2 = 50 min) and another with slow kinetics (T1/2 = 240 min), in wild-type mice. This in vivo methodology will aid in defining the physiological variables that drive efflux, as well as the impact of brain states or disorders on clearance kinetics.
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Affiliation(s)
- Virginia Plá
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Peter Bork
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Aurakoch Harnpramukkul
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Genaro Olveda
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Antonio Ladrón-de-Guevara
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Michael J Giannetto
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Rashad Hussain
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Wei Wang
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Douglas H Kelley
- Department of Mechanical Engineering, University of Rochester, Rochester, NY 14627, USA
| | - Lauren M Hablitz
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA; Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen, Denmark.
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7
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Giannetto MJ, Hablitz LM. Reading to the end(foot): translational readthrough of AQP4 increases amyloid-β clearance. Brain 2022; 145:2943-2945. [PMID: 36004521 DOI: 10.1093/brain/awac289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 08/03/2022] [Indexed: 11/13/2022] Open
Affiliation(s)
- Michael J Giannetto
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Lauren M Hablitz
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
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8
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Abstract
All biological processes including movement, digestion, and thought require energy, and the metabolic activity necessary to generate that energy also generates waste. Metabolic by-products, including a variety of proteins, accumulate in the tissue and can be harmful if not removed. Throughout the body, the lymphatic system is responsible for clearing metabolic waste from the tissue (Figure 1). An ultrafiltrate of blood plasma constantly enters the tissue from the microvasculature and percolates through the tissue before uptake by lymphatic capillaries. Once in these capillaries, a series of lymphatic vessels, pumps, and valves ensures directional fluid movement, ultimately draining the lymph containing waste products back into the venous circulatory system. The liver can be regarded as the ultimate recycling station in the body, where these waste products are either degraded or reused.
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Affiliation(s)
- Lauren M Hablitz
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA; Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark.
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9
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Abstract
The glymphatic system is network of perivascular spaces through which cerebrospinal fluid and interstitial fluid can move through the brain, clearing metabolic waste, such as amyloid beta, lactate and more, from the parenchyma. This cleaning system is regulated by sleep and norepinephrine, with increased levels of norepinephrine during wakefulness inhibiting fluid movement. Norepinephrine is also essential for transition from acute to chronic pain, and sufferers of chronic neuropathic pain frequently present with sleep disruption. These connections among glymphatic clearance, sleep, and pain are very intriguing, and might lead to nonpharmaceutical interventions for pain treatment. This short perspective provides a rationale for the hypothesis that mind-body interventions-such as acupuncture-can reduce norepinephrine and increase glymphatic function, ultimately relieving chronic neuropathic pain.
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Affiliation(s)
- Nanna Goldman
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, USA
| | - Lauren M Hablitz
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, USA
| | - Yuki Mori
- Center for Basic and Translational Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, USA.,Center for Basic and Translational Neuroscience, University of Copenhagen, Copenhagen, Denmark
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Giannetto M, Xia M, Stæger FF, Metcalfe T, Vinitsky HS, Dang JAML, Xavier ALR, Kress BT, Nedergaard M, Hablitz LM. Biological sex does not predict glymphatic influx in healthy young, middle aged or old mice. Sci Rep 2020; 10:16073. [PMID: 32999319 PMCID: PMC7528110 DOI: 10.1038/s41598-020-72621-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 08/10/2020] [Indexed: 11/09/2022] Open
Abstract
Sexual dimorphism is evident in brain structure, size, and function throughout multiple species. Here, we tested whether cerebrospinal fluid entry into the glymphatic system, a network of perivascular fluid transport that clears metabolic waste from the brain, was altered between male and female mice. We analyze glymphatic influx in 244 young reproductive age (2-4 months) C57BL/6 mice. We found no male/female differences in total influx under anesthesia, or across the anterior/posterior axis of the brain. Circadian-dependent changes in glymphatic influx under ketamine/xylazine anesthesia were not altered by sex. This was not true for diurnal rhythms under pentobarbital and avertin, but both still showed daily oscillations independent of biological sex. Finally, although glymphatic influx decreases with age there was no sex difference in total influx or subregion-dependent tracer distribution in 17 middle aged (9-10 months) and 36 old (22-24 months) mice. Overall, in healthy adult C57BL/6 mice we could not detect male/female differences in glymphatic influx. This finding contrasts the gender differences in common neurodegenerative diseases. We propose that additional sex-dependent co-morbidities, such as chronic stress, protein misfolding, traumatic brain injury or other pathological mechanisms may explain the increased risk for developing proteinopathies rather than pre-existing suppression of glymphatic influx.
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Affiliation(s)
- Michael Giannetto
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Maosheng Xia
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, No. 77, Puhe Street, Shenbei District, Shenyang, 110177, People's Republic of China.,Department of Orthopaedics, The First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Frederik Filip Stæger
- Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Tanner Metcalfe
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Hanna S Vinitsky
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Juliana A M L Dang
- Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Anna L R Xavier
- Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Benjamin T Kress
- Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA. .,Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.
| | - Lauren M Hablitz
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
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Hablitz LM, Plá V, Giannetto M, Vinitsky HS, Stæger FF, Metcalfe T, Nguyen R, Benrais A, Nedergaard M. Circadian control of brain glymphatic and lymphatic fluid flow. Nat Commun 2020; 11:4411. [PMID: 32879313 PMCID: PMC7468152 DOI: 10.1038/s41467-020-18115-2] [Citation(s) in RCA: 264] [Impact Index Per Article: 66.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Accepted: 07/24/2020] [Indexed: 12/20/2022] Open
Abstract
The glymphatic system is a network of perivascular spaces that promotes movement of cerebrospinal fluid (CSF) into the brain and clearance of metabolic waste. This fluid transport system is supported by the water channel aquaporin-4 (AQP4) localized to vascular endfeet of astrocytes. The glymphatic system is more effective during sleep, but whether sleep timing promotes glymphatic function remains unknown. We here show glymphatic influx and clearance exhibit endogenous, circadian rhythms peaking during the mid-rest phase of mice. Drainage of CSF from the cisterna magna to the lymph nodes exhibits daily variation opposite to glymphatic influx, suggesting distribution of CSF throughout the animal depends on time-of-day. The perivascular polarization of AQP4 is highest during the rest phase and loss of AQP4 eliminates the day-night difference in both glymphatic influx and drainage to the lymph nodes. We conclude that CSF distribution is under circadian control and that AQP4 supports this rhythm.
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Affiliation(s)
- Lauren M Hablitz
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA.
| | - Virginia Plá
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Michael Giannetto
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Hanna S Vinitsky
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Frederik Filip Stæger
- Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Tanner Metcalfe
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Rebecca Nguyen
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Abdellatif Benrais
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA. .,Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.
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12
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Hablitz LM, Vinitsky HS, Sun Q, Stæger FF, Sigurdsson B, Mortensen KN, Lilius TO, Nedergaard M. Increased glymphatic influx is correlated with high EEG delta power and low heart rate in mice under anesthesia. Sci Adv 2019; 5:eaav5447. [PMID: 30820460 PMCID: PMC6392807 DOI: 10.1126/sciadv.aav5447] [Citation(s) in RCA: 242] [Impact Index Per Article: 48.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 01/14/2019] [Indexed: 05/15/2023]
Abstract
The glymphatic system is responsible for brain-wide delivery of nutrients and clearance of waste via influx of cerebrospinal fluid (CSF) alongside perivascular spaces and through the brain. Glymphatic system activity increases during sleep or ketamine/xylazine (K/X) anesthesia, yet the mechanism(s) facilitating CSF influx are poorly understood. Here, we correlated influx of a CSF tracer into the brain with electroencephalogram (EEG) power, heart rate, blood pressure, and respiratory rate in wild-type mice under six different anesthesia regimens. We found that glymphatic CSF tracer influx was highest under K/X followed by isoflurane (ISO) supplemented with dexmedetomidine and pentobarbital. Mice anesthetized with α-chloralose, Avertin, or ISO exhibited low CSF tracer influx. This is the first study to show that glymphatic influx correlates positively with cortical delta power in EEG recordings and negatively with beta power and heart rate.
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Affiliation(s)
- Lauren M. Hablitz
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Hanna S. Vinitsky
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Qian Sun
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Frederik Filip Stæger
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Björn Sigurdsson
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Kristian N. Mortensen
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Tuomas O. Lilius
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Department of Clinical Pharmacology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Corresponding author.
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13
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Mestre H, Hablitz LM, Xavier AL, Feng W, Zou W, Pu T, Monai H, Murlidharan G, Castellanos Rivera RM, Simon MJ, Pike MM, Plá V, Du T, Kress BT, Wang X, Plog BA, Thrane AS, Lundgaard I, Abe Y, Yasui M, Thomas JH, Xiao M, Hirase H, Asokan A, Iliff JJ, Nedergaard M. Aquaporin-4-dependent glymphatic solute transport in the rodent brain. eLife 2018; 7:40070. [PMID: 30561329 PMCID: PMC6307855 DOI: 10.7554/elife.40070] [Citation(s) in RCA: 317] [Impact Index Per Article: 52.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 12/17/2018] [Indexed: 02/06/2023] Open
Abstract
The glymphatic system is a brain-wide clearance pathway; its impairment contributes to the accumulation of amyloid-β. Influx of cerebrospinal fluid (CSF) depends upon the expression and perivascular localization of the astroglial water channel aquaporin-4 (AQP4). Prompted by a recent failure to find an effect of Aqp4 knock-out (KO) on CSF and interstitial fluid (ISF) tracer transport, five groups re-examined the importance of AQP4 in glymphatic transport. We concur that CSF influx is higher in wild-type mice than in four different Aqp4 KO lines and in one line that lacks perivascular AQP4 (Snta1 KO). Meta-analysis of all studies demonstrated a significant decrease in tracer transport in KO mice and rats compared to controls. Meta-regression indicated that anesthesia, age, and tracer delivery explain the opposing results. We also report that intrastriatal injections suppress glymphatic function. This validates the role of AQP4 and shows that glymphatic studies must avoid the use of invasive procedures.
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Affiliation(s)
- Humberto Mestre
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, United States
| | - Lauren M Hablitz
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, United States
| | - Anna Lr Xavier
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Weixi Feng
- Jiangsu Province Key Laboratory of Neurodegeneration, Center for Global Health, Nanjing Medical University, Nanjing, China
| | - Wenyan Zou
- Jiangsu Province Key Laboratory of Neurodegeneration, Center for Global Health, Nanjing Medical University, Nanjing, China
| | - Tinglin Pu
- Jiangsu Province Key Laboratory of Neurodegeneration, Center for Global Health, Nanjing Medical University, Nanjing, China
| | - Hiromu Monai
- RIKEN Center for Brain Science, Wako, Japan.,Ochanomizu University, Tokyo, Japan
| | - Giridhar Murlidharan
- Gene Therapy Center, The University of North Carolina, Chapel Hill, United States
| | | | - Matthew J Simon
- Department of Anesthesiology and Perioperative Medicine, Oregon Health and Science University, Portland, United States
| | - Martin M Pike
- Advanced Imaging Research Center, Oregon Health and Science University, Portland, United States
| | - Virginia Plá
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, United States
| | - Ting Du
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, United States
| | - Benjamin T Kress
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, United States
| | | | - Benjamin A Plog
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, United States
| | - Alexander S Thrane
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Ophthalmology, Haukeland University Hospital, Bergen, Norway
| | - Iben Lundgaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, United States.,Department of Experimental Medical Science, Lund University, Lund, Sweden.,Wallenberg Center for Molecular Medicine, Lund University, Lund, Sweden
| | - Yoichiro Abe
- Department of Pharmacology,School of Medicine, Keio University, Tokyo, Japan
| | - Masato Yasui
- Department of Pharmacology,School of Medicine, Keio University, Tokyo, Japan
| | - John H Thomas
- Department of Mechanical Engineering, University of Rochester, Rochester, United States.,Department of Physics and Astronomy, University of Rochester, Rochester, United States
| | - Ming Xiao
- Jiangsu Province Key Laboratory of Neurodegeneration, Center for Global Health, Nanjing Medical University, Nanjing, China
| | - Hajime Hirase
- RIKEN Center for Brain Science, Wako, Japan.,Brain and Body System Science Institute, Saitama University, Saitama, Japan
| | - Aravind Asokan
- Gene Therapy Center, The University of North Carolina, Chapel Hill, United States.,Department of Molecular Genetics and Microbiology, Duke University School of Medicine, North Carolina, United States.,Department of Surgery, Duke University School of Medicine, Durham, United States
| | - Jeffrey J Iliff
- Department of Anesthesiology and Perioperative Medicine, Oregon Health and Science University, Portland, United States.,Knight Cardiovascular Institute, Oregon Health and Science University, Portland, United States
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, United States.,Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Copenhagen, Denmark
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14
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Fargason RE, Fobian AD, Hablitz LM, Paul JR, White BA, Cropsey KL, Gamble KL. Correcting delayed circadian phase with bright light therapy predicts improvement in ADHD symptoms: A pilot study. J Psychiatr Res 2017; 91:105-110. [PMID: 28327443 PMCID: PMC7959333 DOI: 10.1016/j.jpsychires.2017.03.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 03/02/2017] [Accepted: 03/02/2017] [Indexed: 12/18/2022]
Abstract
Attention-deficit/hyperactivity disorder (ADHD) is a common condition with comorbid insomnia reported in >70% of children and adults. These patients demonstrate delays in sleep-wake rhythms, nocturnal rise in melatonin, and early morning rise in cortisol. Given that standard psychopharmacologic treatments for ADHD often do not completely control symptoms in participants with circadian rhythm delay, we sought to test whether bright light therapy (BLT) advances circadian rhythms and further reduces ADHD symptoms over standard treatments. In addition to standard of care, participants with ADHD diagnosis underwent 1 week of baseline assessment followed by 2-weeks of 30-min morning 10,000-lux BLT beginning 3 h after mid-sleep time. Participants minimized overhead light after 4 p.m., wore an actigraphy watch, and recorded BLT time on daily sleep logs. Dim Light Melatonin Onset (DLMO) was assessed at baseline and after 2-week treatment. ADHD symptoms were measured by the ADHD-Rating Scales (ADHD-RS). BLT significantly advanced the phase of DLMO by 31 min [mean time (SEM), 20:36 (0:21) advanced to 20:05 (0:20)] and mid-sleep time by 57 min [4:37 (0:22) advanced to 3:40 (0:16); paired t-tests, p = 0.002 and 0.004, respectively). Phase advances (in DLMO or mid-sleep time) were significantly correlated with decreased ADHD-RS total scores (p = 0.027 and 0.044) and Hyperactive-Impulsive sub-scores (p = 0.014 and 0.013, respectively). Actigraphy analysis for a subset of 8 participants with significant DLMO phase advance revealed no significant changes in total sleep time, sleep efficiency, wake after sleep onset, or percent wake during sleep interval. This is the first successful use of BLT for advancing melatonin phase and improving ADHD symptoms in adults. BLT may be a complementary treatment for both delayed sleep timing and ADHD symptoms in adults.
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Affiliation(s)
- Rachel E Fargason
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Aaron D Fobian
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Lauren M Hablitz
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jodi R Paul
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Brittny A White
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Karen L Cropsey
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Karen L Gamble
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA.
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15
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Besing RC, Rogers CO, Paul JR, Hablitz LM, Johnson RL, McMahon LL, Gamble KL. GSK3 activity regulates rhythms in hippocampal clock gene expression and synaptic plasticity. Hippocampus 2017; 27:890-898. [PMID: 28556462 PMCID: PMC5511075 DOI: 10.1002/hipo.22739] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [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: 11/04/2016] [Revised: 04/26/2017] [Accepted: 05/02/2017] [Indexed: 11/09/2022]
Abstract
Hippocampal rhythms in clock gene expression, enzymatic activity, and long-term potentiation (LTP) are thought to underlie day-night differences in memory acquisition and recall. Glycogen synthase kinase 3-beta (GSK3β) is a known regulator of hippocampal function, and inhibitory phosphorylation of GSK3β exhibits region-specific differences over the light-dark cycle. Here, we sought to determine whether phosphorylation of both GSK3α and GSK3β isoforms has an endogenous circadian rhythm in specific areas of the hippocampus and whether chronic inhibition or activation alters the molecular clock and hippocampal plasticity (LTP). Results indicated a significant endogenous circadian rhythm in phosphorylation of GSK3β, but not GSK3α, in hippocampal CA1 extracts from mice housed in constant darkness for at least 2 weeks. To examine the importance of this rhythm, genetic and pharmacological strategies were used to disrupt the GSK3 activity rhythm by chronically activating or inhibiting GSK3. Chronic activation of both GSK3 isoforms in transgenic mice (GSK3-KI mice) diminished rhythmic BMAL1 expression. On the other hand, chronic treatment with a GSK3 inhibitor significantly shortened the molecular clock period of organotypic hippocampal PER2::LUC cultures. While WT mice exhibited higher LTP magnitude at night compared to day, the day-night difference in LTP magnitude remained with greater magnitude at both times of day in mice with chronic GSK3 activity. On the other hand, pharmacological GSK3 inhibition impaired day-night differences in LTP by blocking LTP selectively at night. Taken together, these results support the model that circadian rhythmicity of hippocampal GSK3β activation state regulates day/night differences in molecular clock periodicity and a major form of synaptic plasticity (LTP).
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Affiliation(s)
- Rachel C. Besing
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Courtney O. Rogers
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jodi R. Paul
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Lauren M. Hablitz
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Russell L. Johnson
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Lori L. McMahon
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Karen L. Gamble
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
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16
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Besing RC, Paul JR, Hablitz LM, Rogers CO, Johnson RL, Young ME, Gamble KL. Circadian rhythmicity of active GSK3 isoforms modulates molecular clock gene rhythms in the suprachiasmatic nucleus. J Biol Rhythms 2015; 30:155-60. [PMID: 25724980 PMCID: PMC4586074 DOI: 10.1177/0748730415573167] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [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] [Indexed: 11/17/2022]
Abstract
The suprachiasmatic nucleus (SCN) drives and synchronizes daily rhythms at the cellular level via transcriptional-translational feedback loops comprising clock genes such as Bmal1 and Period (Per). Glycogen synthase kinase 3 (GSK3), a serine/threonine kinase, phosphorylates at least 5 core clock proteins and shows diurnal variation in phosphorylation state (inactivation) of the GSK3β isoform. Whether phosphorylation of the other primary isoform (GSK3α) varies across the subjective day-night cycle is unknown. The purpose of this study was to determine if the endogenous rhythm of GSK3 (α and β) phosphorylation is critical for rhythmic BMAL1 expression and normal amplitude and periodicity of the molecular clock in the SCN. Significant circadian rhythmicity of phosphorylated GSK3 (α and β) was observed in the SCN from wild-type mice housed in constant darkness for 2 weeks. Importantly, chronic activation of both GSK3 isoforms impaired rhythmicity of the GSK3 target BMAL1. Furthermore, chronic pharmacological inhibition of GSK3 with 20 µM CHIR-99021 enhanced the amplitude and shortened the period of PER2::luciferase rhythms in organotypic SCN slice cultures. These results support the model that GSK3 activity status is regulated by the circadian clock and that GSK3 feeds back to regulate the molecular clock amplitude in the SCN.
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Affiliation(s)
| | - Jodi R Paul
- Department of Psychiatry and Behavioral Neurobiology
| | | | | | | | - Martin E Young
- Division of Cardiovascular Diseases, Department of Medicine; University of Alabama at Birmingham, Birmingham, Alabama
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17
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Hablitz LM, Molzof HE, Paul JR, Johnson RL, Gamble KL. Suprachiasmatic nucleus function and circadian entrainment are modulated by G protein-coupled inwardly rectifying (GIRK) channels. J Physiol 2014; 592:5079-92. [PMID: 25217379 DOI: 10.1113/jphysiol.2014.282079] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
G protein signalling within the central circadian oscillator, the suprachiasmatic nucleus (SCN), is essential for conveying time-of-day information. We sought to determine whether G protein-coupled inwardly rectifying potassium channels (GIRKs) modulate SCN physiology and circadian behaviour. We show that GIRK current and GIRK2 protein expression are greater during the day. Pharmacological inhibition of GIRKs and genetic loss of GIRK2 depolarized the day-time resting membrane potential of SCN neurons compared to controls. Behaviourally, GIRK2 knockout (KO) mice failed to shorten free running period in response to wheel access in constant darkness and entrained more rapidly to a 6 h advance of a 12 h:12 h light-dark (LD) cycle than wild-type (WT) littermate controls. We next examined whether these effects were due to disrupted signalling of neuropeptide Y (NPY), which is known to mediate non-photic phase shifts, attenuate photic phase shifts and activate GIRKs. Indeed, GIRK2 KO SCN slices had significantly fewer silent cells in response to NPY, likely contributing to the absence of NPY-induced phase advances of PER2::LUC rhythms in organotypic SCN cultures from GIRK2 KO mice. Finally, GIRK channel activation is sufficient to cause a non-photic-like phase advance of PER2::LUC rhythms on a Per2(Luc+/-) background. These results suggest that rhythmic regulation of GIRK2 protein and channel function in the SCN contributes to day-time resting membrane potential, providing a mechanism for the fine tuning responses to non-photic and photic stimuli. Further investigation could provide insight into disorders with circadian disruption comorbidities such as epilepsy and addiction, in which GIRK channels have been implicated.
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Affiliation(s)
- L M Hablitz
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - H E Molzof
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - J R Paul
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - R L Johnson
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - K L Gamble
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
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18
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Besing RC, Hablitz LM, Paul JR, Johnson RL, Prosser RA, Gamble KL. Neuropeptide Y-induced phase shifts of PER2::LUC rhythms are mediated by long-term suppression of neuronal excitability in a phase-specific manner. Chronobiol Int 2012; 29:91-102. [PMID: 22324550 DOI: 10.3109/07420528.2011.649382] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Endogenous circadian rhythms are entrained to the 24-h light/dark cycle by both light and nonphotic stimuli. During the day, nonphotic stimuli, such as novel wheel-induced exercise, produce large phase advances. Neuropeptide Y (NPY) release from the thalamus onto suprachiasmatic nucleus (SCN) neurons at least partially mediates this nonphotic signal. The authors examined the hypothesis that NPY-induced phase advances are accompanied by suppression of PER2 and are mediated by long-term depression of neuronal excitability in a phase-specific manner. First, it was found that NPY-induced phase advances in PER2::LUC SCN cultures are largest when NPY (2.35 µM) is given in the early part of the day (circadian time [CT] 0-6). In addition, PER2::LUC levels in NPY-treated (compared to vehicle-treated) samples were suppressed beginning 6-7 h after treatment. Similar NPY application to organotypic Per1::GFP SCN cultures resulted in long-term suppression of spike rate of green fluorescent protein-positive (GFP+) cells when slices were treated with NPY during the early or middle of the day (zeitgeber time [ZT] 2 or 6), but not during the late day (ZT 10). Furthermore, 1-h bath application of NPY to acute SCN brain slices decreased general neuronal activity measured through extracellular recordings. Finally, NPY-induced phase advances of PER2::LUC rhythms were blocked by latent depolarization with 34.5 mM K(+) 3 h after NPY application. These results suggest that NPY-induced phase advances may be mediated by long-term depression of neuronal excitability. This model is consistent with findings in other brain regions that NPY-induced persistent hyperpolarization underlies mechanisms of energy homeostasis, anxiety-related behavior, and thalamocortical synchronous firing.
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Affiliation(s)
- Rachel C Besing
- Department of Psychiatry and Behavioral Neurobiology , University of Alabama at Birmingham , Birmingham, AL 35294-0017, USA
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