Progressive tauopathy disrupts breathing stability and chemoreflexes during presumptive sleep in mice

Rationale: Although sleep apnea occurs in over 50% of individuals with Alzheimer’s Disease (AD) or related tauopathies, little is known concerning the potential role of tauopathy in the pathogenesis of sleep apnea. Here, we tested the hypotheses that, during presumptive sleep, a murine model of tauo...

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Main Authors: Alexandria B. Marciante, Carter Lurk, Luz Mata, Jada Lewis, Leah R. Reznikov, Gordon S. Mitchell
Format: Article
Language:English
Published: Frontiers Media S.A. 2023-09-01
Series:Frontiers in Physiology
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fphys.2023.1272980/full
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author Alexandria B. Marciante
Carter Lurk
Luz Mata
Jada Lewis
Leah R. Reznikov
Gordon S. Mitchell
author_facet Alexandria B. Marciante
Carter Lurk
Luz Mata
Jada Lewis
Leah R. Reznikov
Gordon S. Mitchell
author_sort Alexandria B. Marciante
collection DOAJ
description Rationale: Although sleep apnea occurs in over 50% of individuals with Alzheimer’s Disease (AD) or related tauopathies, little is known concerning the potential role of tauopathy in the pathogenesis of sleep apnea. Here, we tested the hypotheses that, during presumptive sleep, a murine model of tauopathy (rTg4510) exhibits: 1) increased breathing instability; 2) impaired chemoreflex function; and 3) exacerbation of these effects with tauopathy progression.Methods: rTg4510 mice initially develop robust tauopathy in the hippocampus and cortex, and eventually progresses to the brainstem. Type I and II post-sigh apnea, Type III (spontaneous) apnea, sigh, and hypopnea incidence were measured in young adult (5–6 months; n = 10–14/group) and aged (13–15 months; n = 22–24/group) non-transgenic (nTg), monogenic control tetracycline transactivator, and bigenic rTg4510 mice using whole-body plethysmography during presumptive sleep (i.e., eyes closed, curled/laying posture, stable breathing for >200 breaths) while breathing room air (21% O2). Peripheral and central chemoreceptor sensitivity were assessed with transient exposures (5 min) to hyperoxia (100% O2) or hypercapnia (3% and 5% CO2 in 21% O2), respectively.Results: We report significant increases in Type I, II, and III apneas (all p < 0.001), sighs (p = 0.002) and hypopneas (p < 0.001) in aged rTg4510 mice, but only Type III apneas in young adult rTg4510 mice (p < 0.001) versus age-matched nTg controls. Aged rTg4510 mice exhibited profound chemoreflex impairment versus age matched nTg and tTA mice. In rTg4510 mice, breathing frequency, tidal volume and minute ventilation were not affected by hyperoxic or hypercapnic challenges, in striking contrast to controls. Histological examination revealed hyperphosphorylated tau in brainstem regions involved in the control of breathing (e.g., pons, medullary respiratory column, retrotrapezoid nucleus) in aged rTg4510 mice. Neither breathing instability nor hyperphosphorylated tau in brainstem tissues were observed in young adult rTg4510 mice.Conclusion: Older rTg4510 mice exhibit profound impairment in the neural control of breathing, with greater breathing instability and near absence of oxygen and carbon-dioxide chemoreflexes. Breathing impairments paralleled tauopathy progression into brainstem regions that control breathing. These findings are consistent with the idea that tauopathy per se undermines chemoreflexes and promotes breathing instability during sleep.
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spelling doaj.art-26bcfa8ae95e4f03b124ee314126cac62023-09-21T13:11:28ZengFrontiers Media S.A.Frontiers in Physiology1664-042X2023-09-011410.3389/fphys.2023.12729801272980Progressive tauopathy disrupts breathing stability and chemoreflexes during presumptive sleep in miceAlexandria B. Marciante0Carter Lurk1Luz Mata2Jada Lewis3Leah R. Reznikov4Gordon S. Mitchell5Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL, United StatesBreathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL, United StatesDepartment of Physiological Sciences, University of Florida, Gainesville, FL, United StatesCenter for Translational Research in Neurodegenerative Diseases, Department of Neuroscience, University of Florida, Gainesville, FL, United StatesDepartment of Physiological Sciences, University of Florida, Gainesville, FL, United StatesBreathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL, United StatesRationale: Although sleep apnea occurs in over 50% of individuals with Alzheimer’s Disease (AD) or related tauopathies, little is known concerning the potential role of tauopathy in the pathogenesis of sleep apnea. Here, we tested the hypotheses that, during presumptive sleep, a murine model of tauopathy (rTg4510) exhibits: 1) increased breathing instability; 2) impaired chemoreflex function; and 3) exacerbation of these effects with tauopathy progression.Methods: rTg4510 mice initially develop robust tauopathy in the hippocampus and cortex, and eventually progresses to the brainstem. Type I and II post-sigh apnea, Type III (spontaneous) apnea, sigh, and hypopnea incidence were measured in young adult (5–6 months; n = 10–14/group) and aged (13–15 months; n = 22–24/group) non-transgenic (nTg), monogenic control tetracycline transactivator, and bigenic rTg4510 mice using whole-body plethysmography during presumptive sleep (i.e., eyes closed, curled/laying posture, stable breathing for >200 breaths) while breathing room air (21% O2). Peripheral and central chemoreceptor sensitivity were assessed with transient exposures (5 min) to hyperoxia (100% O2) or hypercapnia (3% and 5% CO2 in 21% O2), respectively.Results: We report significant increases in Type I, II, and III apneas (all p < 0.001), sighs (p = 0.002) and hypopneas (p < 0.001) in aged rTg4510 mice, but only Type III apneas in young adult rTg4510 mice (p < 0.001) versus age-matched nTg controls. Aged rTg4510 mice exhibited profound chemoreflex impairment versus age matched nTg and tTA mice. In rTg4510 mice, breathing frequency, tidal volume and minute ventilation were not affected by hyperoxic or hypercapnic challenges, in striking contrast to controls. Histological examination revealed hyperphosphorylated tau in brainstem regions involved in the control of breathing (e.g., pons, medullary respiratory column, retrotrapezoid nucleus) in aged rTg4510 mice. Neither breathing instability nor hyperphosphorylated tau in brainstem tissues were observed in young adult rTg4510 mice.Conclusion: Older rTg4510 mice exhibit profound impairment in the neural control of breathing, with greater breathing instability and near absence of oxygen and carbon-dioxide chemoreflexes. Breathing impairments paralleled tauopathy progression into brainstem regions that control breathing. These findings are consistent with the idea that tauopathy per se undermines chemoreflexes and promotes breathing instability during sleep.https://www.frontiersin.org/articles/10.3389/fphys.2023.1272980/fulltauopathysleep-disordered breathingchemoreflexsleep apneaplethysmography
spellingShingle Alexandria B. Marciante
Carter Lurk
Luz Mata
Jada Lewis
Leah R. Reznikov
Gordon S. Mitchell
Progressive tauopathy disrupts breathing stability and chemoreflexes during presumptive sleep in mice
Frontiers in Physiology
tauopathy
sleep-disordered breathing
chemoreflex
sleep apnea
plethysmography
title Progressive tauopathy disrupts breathing stability and chemoreflexes during presumptive sleep in mice
title_full Progressive tauopathy disrupts breathing stability and chemoreflexes during presumptive sleep in mice
title_fullStr Progressive tauopathy disrupts breathing stability and chemoreflexes during presumptive sleep in mice
title_full_unstemmed Progressive tauopathy disrupts breathing stability and chemoreflexes during presumptive sleep in mice
title_short Progressive tauopathy disrupts breathing stability and chemoreflexes during presumptive sleep in mice
title_sort progressive tauopathy disrupts breathing stability and chemoreflexes during presumptive sleep in mice
topic tauopathy
sleep-disordered breathing
chemoreflex
sleep apnea
plethysmography
url https://www.frontiersin.org/articles/10.3389/fphys.2023.1272980/full
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