1
|
Crowthers R, Thi Mong Nguyen T, Martinez D. Circadian disruptions and their role in the development of hypertension. Front Neurosci 2024; 18:1433512. [PMID: 39170672 PMCID: PMC11335678 DOI: 10.3389/fnins.2024.1433512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Accepted: 07/22/2024] [Indexed: 08/23/2024] Open
Abstract
Circadian fluctuations in physiological setpoints are determined by the suprachiasmatic nucleus (SCN) which exerts control over many target structures within and beyond the hypothalamus via projections. The SCN, or central pacemaker, orchestrates synchrony between the external environment and the internal circadian mechanism. The resulting cycles in hormone levels and autonomic nervous system (ANS) activity provide precise messages to specific organs, adjusting, for example, their sensitivity to approaching hormones or metabolites. The SCN responds to both photic (light) and non-photic input. Circadian patterns are found in both heart rate and blood pressure, which are linked to daily variations in activity and autonomic nervous system activity. Variations in blood pressure are of great interest as several cardiovascular diseases such as stroke, arrhythmias, and hypertension are linked to circadian rhythm dysregulation. The disruption of normal day-night cycles, such as in shift work, social jetlag, or eating outside of normal hours leads to desynchronization of the central and peripheral clocks. This desynchronization leads to disorganization of the cellular processes that are normally driven by the interactions of the SCN and photic input. Here, we review autonomic system function and dysfunction due to regulation and interaction between different cardiorespiratory brain centers and the SCN, as well as social, lifestyle, and external factors that may impact the circadian control of blood pressure.
Collapse
|
2
|
Jones AA, Marino GM, Arble DM. Time-restricted feeding reveals a role for neural respiratory clocks in optimizing daily ventilatory-metabolic coupling in mice. Am J Physiol Endocrinol Metab 2024; 327:E111-E120. [PMID: 38836780 DOI: 10.1152/ajpendo.00111.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 05/28/2024] [Accepted: 05/28/2024] [Indexed: 06/06/2024]
Abstract
The master circadian clock, located in the suprachiasmatic nuclei (SCN), organizes the daily rhythm in minute ventilation (V̇e). However, the extent that the daily rhythm in V̇e is secondary to SCN-imposed O2 and CO2 cycles (i.e., metabolic rate) or driven by other clock mechanisms remains unknown. Here, we experimentally shifted metabolic rate using time-restricted feeding (without affecting light-induced synchronization of the SCN) to determine the influence of metabolic rate in orchestrating the daily V̇e rhythm. Mice eating predominantly at night exhibited robust daily rhythms in O2 consumption (V̇o2), CO2 production (V̇co2), and V̇e with similar peak times (approximately ZT18) that were consistent with SCN organization. However, feeding mice exclusively during the day separated the relative timing of metabolic and ventilatory rhythms, resulting in an approximately 8.5-h advance in V̇co2 and a disruption of the V̇e rhythm, suggesting opposing circadian and metabolic influences on V̇e. To determine if the molecular clock of cells involved in the neural control of breathing contributes to the daily V̇e rhythm, we examined V̇e in mice lacking BMAL1 in Phox2b-expressing respiratory cells (i.e., BKOP mice). The ventilatory and metabolic rhythms of predominantly night-fed BKOP mice did not differ from wild-type mice. However, in contrast to wild-type mice, exclusive day feeding of BKOP mice led to an unfettered daily V̇e rhythm with a peak time aligning closely with the daily V̇co2 rhythm. Taken together, these results indicate that both daily V̇co2 changes and intrinsic circadian time-keeping within Phox2b respiratory cells are predominant orchestrators of the daily rhythm in ventilation.NEW & NOTEWORTHY The master circadian clock organizes the daily rhythm in ventilation; however, the extent that this rhythm is driven by SCN regulation of metabolic rate versus other clock mechanisms remains unknown. We report that metabolic rate alone is insufficient to explain the daily oscillation in ventilation and that neural respiratory clocks within Phox2b-expressing cells additionally optimize breathing. Collectively, these findings advance our mechanistic understanding of the circadian rhythm in ventilatory control.
Collapse
Affiliation(s)
- Aaron A Jones
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin, United States
| | - Gabriella M Marino
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin, United States
| | - Deanna M Arble
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin, United States
| |
Collapse
|
3
|
Li W, Tiedt S, Lawrence JH, Harrington ME, Musiek ES, Lo EH. Circadian Biology and the Neurovascular Unit. Circ Res 2024; 134:748-769. [PMID: 38484026 DOI: 10.1161/circresaha.124.323514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 02/14/2024] [Indexed: 03/19/2024]
Abstract
Mammalian physiology and cellular function are subject to significant oscillations over the course of every 24-hour day. It is likely that these daily rhythms will affect function as well as mechanisms of disease in the central nervous system. In this review, we attempt to survey and synthesize emerging studies that investigate how circadian biology may influence the neurovascular unit. We examine how circadian clocks may operate in neural, glial, and vascular compartments, review how circadian mechanisms regulate cell-cell signaling, assess interactions with aging and vascular comorbidities, and finally ask whether and how circadian effects and disruptions in rhythms may influence the risk and progression of pathophysiology in cerebrovascular disease. Overcoming identified challenges and leveraging opportunities for future research might support the development of novel circadian-based treatments for stroke.
Collapse
Affiliation(s)
- Wenlu Li
- Neuroprotection Research Laboratories, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston (W.L., E.H.L.)
- Consortium International pour la Recherche Circadienne sur l'AVC, Munich, Germany (W.L., S.T., J.H.L., M.E.H., E.S.M., E.H.L.)
| | - Steffen Tiedt
- Consortium International pour la Recherche Circadienne sur l'AVC, Munich, Germany (W.L., S.T., J.H.L., M.E.H., E.S.M., E.H.L.)
- Institute for Stroke and Dementia Research, University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany (S.T.)
| | - Jennifer H Lawrence
- Consortium International pour la Recherche Circadienne sur l'AVC, Munich, Germany (W.L., S.T., J.H.L., M.E.H., E.S.M., E.H.L.)
- Department of Neurology, Washington University School of Medicine, St. Louis, MO (J.H.L., E.S.M.)
| | - Mary E Harrington
- Consortium International pour la Recherche Circadienne sur l'AVC, Munich, Germany (W.L., S.T., J.H.L., M.E.H., E.S.M., E.H.L.)
- Neuroscience Program, Smith College, Northampton, MA (M.E.H.)
| | - Erik S Musiek
- Consortium International pour la Recherche Circadienne sur l'AVC, Munich, Germany (W.L., S.T., J.H.L., M.E.H., E.S.M., E.H.L.)
- Department of Neurology, Washington University School of Medicine, St. Louis, MO (J.H.L., E.S.M.)
| | - Eng H Lo
- Neuroprotection Research Laboratories, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston (W.L., E.H.L.)
- Consortium International pour la Recherche Circadienne sur l'AVC, Munich, Germany (W.L., S.T., J.H.L., M.E.H., E.S.M., E.H.L.)
| |
Collapse
|
4
|
Ragozzino FJ, Karatsoreos IN, Peters JH. Principles of synaptic encoding of brainstem circadian rhythms. Exp Physiol 2024. [PMID: 38308846 DOI: 10.1113/ep090867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Accepted: 01/16/2024] [Indexed: 02/05/2024]
Abstract
Circadian regulation of autonomic tone and reflex pathways pairs physiological processes with the daily light cycle. However, the underlying mechanisms mediating these changes on autonomic neurocircuitry are only beginning to be understood. The brainstem nucleus of the solitary tract (NTS) and adjacent nuclei, including the area postrema and dorsal motor nucleus of the vagus, are key candidates for rhythmic control of some aspects of the autonomic nervous system. Recent findings have contributed to a working model of circadian regulation in the brainstem which manifests from the transcriptional, to synaptic, to circuit levels of organization. Vagal afferent neurons and the NTS possess rhythmic clock gene expression, rhythmic action potential firing, and our recent findings demonstrate rhythmic spontaneous glutamate release. In addition, postsynaptic conductances also vary across the day producing subtle changes in membrane depolarization which govern synaptic efficacy. Together these coordinated pre- and postsynaptic changes provide nuanced control of synaptic transmission across the day to tune the sensitivity of primary afferent input and likely govern reflex output. Further, given the important role for the brainstem in integrating cues such as feeding, cardiovascular function and temperature, it may also be an underappreciated locus in mediating the effects of such non-photic entraining cues. This short review focuses on the neurophysiological principles that govern NTS synaptic transmission and how circadian rhythms impacted them across the day.
Collapse
Affiliation(s)
- Forrest J Ragozzino
- Department of Integrative Physiology and Neuroscience, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
| | - Ilia N Karatsoreos
- Department of Psychological and Brain Sciences, University of Massachusetts Amherst, Amherst, Massachusetts, USA
| | - James H Peters
- Department of Integrative Physiology and Neuroscience, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
| |
Collapse
|
5
|
Smith MN, Girgis D. Sleep tight, beat right: Does nucleus of the solitary tract circadian rhythmicity influence blood pressure and sleep regulation? J Physiol 2023; 601:4267-4269. [PMID: 37665176 DOI: 10.1113/jp285276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/05/2023] Open
Affiliation(s)
- Meagan N Smith
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Canada
| | - David Girgis
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Canada
| |
Collapse
|
6
|
Page AJ. Plasticity of gastrointestinal vagal afferents in terms of feeding-related physiology and pathophysiology. J Physiol 2023. [PMID: 37737742 DOI: 10.1113/jp284075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 09/07/2023] [Indexed: 09/23/2023] Open
Abstract
Gastrointestinal vagal afferents play an important role in communicating food related information from the gut to the brain. This information initiates vago-vagal reflexes essential for gut functions, including gut motility and secretions. These afferents also play a role in energy homeostasis, signalling the arrival, amount and nutrient composition of a meal to the central nervous system where it is processed ultimately leading to termination of a meal. Vagal afferent responses to food related stimuli demonstrate a high degree of plasticity, responding to short term changes in nutritional demand, such as the fluctuations that occur across a 24-hr or in response to a fast, as well as long term changes in energy demand, such as occurs during pregnancy. This plasticity is disrupted in disease states, such as obesity or chronic stress where there is hypo- and hypersensitivity of these afferents, respectively. Improved understanding of the plasticity of these afferents will enable identification of new treatment options for diseases associated with vagal afferent function.
Collapse
Affiliation(s)
- Amanda J Page
- Vagal Afferent Research Group, School of Biomedicine, University of Adelaide, Adelaide, South Australia, Australia
- Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute, SAHMRI, Adelaide, South Australia, Australia
| |
Collapse
|
7
|
Hibberd TJ, Ramsay S, Spencer-Merris P, Dinning PG, Zagorodnyuk VP, Spencer NJ. Circadian rhythms in colonic function. Front Physiol 2023; 14:1239278. [PMID: 37711458 PMCID: PMC10498548 DOI: 10.3389/fphys.2023.1239278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 08/17/2023] [Indexed: 09/16/2023] Open
Abstract
A rhythmic expression of clock genes occurs within the cells of multiple organs and tissues throughout the body, termed "peripheral clocks." Peripheral clocks are subject to entrainment by a multitude of factors, many of which are directly or indirectly controlled by the light-entrainable clock located in the suprachiasmatic nucleus of the hypothalamus. Peripheral clocks occur in the gastrointestinal tract, notably the epithelia whose functions include regulation of absorption, permeability, and secretion of hormones; and in the myenteric plexus, which is the intrinsic neural network principally responsible for the coordination of muscular activity in the gut. This review focuses on the physiological circadian variation of major colonic functions and their entraining mechanisms, including colonic motility, absorption, hormone secretion, permeability, and pain signalling. Pathophysiological states such as irritable bowel syndrome and ulcerative colitis and their interactions with circadian rhythmicity are also described. Finally, the classic circadian hormone melatonin is discussed, which is expressed in the gut in greater quantities than the pineal gland, and whose exogenous use has been of therapeutic interest in treating colonic pathophysiological states, including those exacerbated by chronic circadian disruption.
Collapse
Affiliation(s)
- Timothy J. Hibberd
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Stewart Ramsay
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | | | - Phil G. Dinning
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
- Colorectal Surgical Unit, Division of Surgery, Flinders Medical Centre, Adelaide, SA, Australia
| | | | - Nick J. Spencer
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| |
Collapse
|