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Norton CE, Shaw RL, Safa, Dockery B, Domeier TL, Segal SS. Advanced age and female sex protect cerebral arteries from mitochondrial depolarization and apoptosis during acute oxidative stress. Aging Cell 2024; 23:e14110. [PMID: 38380477 PMCID: PMC11113258 DOI: 10.1111/acel.14110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 01/26/2024] [Accepted: 01/30/2024] [Indexed: 02/22/2024] Open
Abstract
Aging increases reactive oxygen species (ROS) which can impair vascular function and contribute to brain injury. However, aging can also promote resilience to acute oxidative stress. Therefore, we tested the hypothesis that advanced age protects smooth muscle cells (SMCs) and endothelial cells (ECs) of posterior cerebral arteries (PCAs; diameter, ∼80 μm) during exposure to H2O2. PCAs from young (4-6 months) and old (20-26 months) male and female C57BL/6 mice were isolated and pressurized (~70 mm Hg) to evaluate cell death, mitochondrial membrane potential (ΔΨm), ROS production, and [Ca2+]i in response to H2O2 (200 μM, 50 min). SMC death and ΔΨm depolarization were greater in PCAs from males vs. females. Aging increased ROS in PCAs from both sexes but increased SMC resilience to death only in males. Inhibiting TRPV4 channels with HC-067047 (1 μM) or Src kinases with SU6656 (10 μM) reduced Ca2+ entry and SMC death to H2O2 most effectively in PCAs from young males. Activating TRPV4 channels with GSK1016790A (50 nM) evoked greater Ca2+ influx in SMCs and ECs of PCAs from young vs. old mice but did not induce cell death. However, when combined with H2O2, TRPV4 activation exacerbated EC death. Activating Src kinases with spermidine (100 μM) increased Ca2+ influx in PCAs from males vs. females with minimal cell death. We conclude that in males, chronic oxidative stress during aging increases the resilience of cerebral arteries, which contrasts with inherent protection in females. Findings implicate TRP channels and Src kinases as targets to limit vascular damage to acute oxidative injury.
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Affiliation(s)
- Charles E. Norton
- Department of Medical Pharmacology and PhysiologyUniversity of MissouriColumbiaMissouriUSA
| | - Rebecca L. Shaw
- Department of Medical Pharmacology and PhysiologyUniversity of MissouriColumbiaMissouriUSA
| | - Safa
- Department of Medical Pharmacology and PhysiologyUniversity of MissouriColumbiaMissouriUSA
| | - Beyoncé Dockery
- Department of Medical Pharmacology and PhysiologyUniversity of MissouriColumbiaMissouriUSA
| | - Timothy L. Domeier
- Department of Medical Pharmacology and PhysiologyUniversity of MissouriColumbiaMissouriUSA
| | - Steven S. Segal
- Department of Medical Pharmacology and PhysiologyUniversity of MissouriColumbiaMissouriUSA
- Dalton Cardiovascular Research CenterColumbiaMissouriUSA
- Department of Biomedical SciencesUniversity of MissouriColumbiaMissouriUSA
- Department of Biomedical, Biological and Chemical EngineeringUniversity of MissouriColumbiaMissouriUSA
- Department of Nutrition and Exercise PhysiologyUniversity of MissouriColumbiaMissouriUSA
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2
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Behringer EJ. Impact of aging on vascular ion channels: perspectives and knowledge gaps across major organ systems. Am J Physiol Heart Circ Physiol 2023; 325:H1012-H1038. [PMID: 37624095 PMCID: PMC10908410 DOI: 10.1152/ajpheart.00288.2023] [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: 05/16/2023] [Revised: 08/21/2023] [Accepted: 08/21/2023] [Indexed: 08/26/2023]
Abstract
Individuals aged ≥65 yr will comprise ∼20% of the global population by 2030. Cardiovascular disease remains the leading cause of death in the world with age-related endothelial "dysfunction" as a key risk factor. As an organ in and of itself, vascular endothelium courses throughout the mammalian body to coordinate blood flow to all other organs and tissues (e.g., brain, heart, lung, skeletal muscle, gut, kidney, skin) in accord with metabolic demand. In turn, emerging evidence demonstrates that vascular aging and its comorbidities (e.g., neurodegeneration, diabetes, hypertension, kidney disease, heart failure, and cancer) are "channelopathies" in large part. With an emphasis on distinct functional traits and common arrangements across major organs systems, the present literature review encompasses regulation of vascular ion channels that underlie blood flow control throughout the body. The regulation of myoendothelial coupling and local versus conducted signaling are discussed with new perspectives for aging and the development of chronic diseases. Although equipped with an awareness of knowledge gaps in the vascular aging field, a section has been included to encompass general feasibility, role of biological sex, and additional conceptual and experimental considerations (e.g., cell regression and proliferation, gene profile analyses). The ultimate goal is for the reader to see and understand major points of deterioration in vascular function while gaining the ability to think of potential mechanistic and therapeutic strategies to sustain organ perfusion and whole body health with aging.
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Affiliation(s)
- Erik J Behringer
- Basic Sciences, Loma Linda University, Loma Linda, California, United States
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3
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Norton CE, Shaw RL, Segal SS. Differential Effects of High Fat Diets on Resilience to H 2O 2-Induced Cell Death in Mouse Cerebral Arteries: Role for Processed Carbohydrates. Antioxidants (Basel) 2023; 12:1433. [PMID: 37507971 PMCID: PMC10376469 DOI: 10.3390/antiox12071433] [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: 06/06/2023] [Revised: 06/30/2023] [Accepted: 07/11/2023] [Indexed: 07/30/2023] Open
Abstract
High fat, western-style diets increase vascular oxidative stress. We hypothesized that smooth muscle cells and endothelial cells adapt during the consumption of high fat diets to become more resilient to acute oxidative stress. Male C57Bl/6J mice were fed a western-style diet high in fat and processed carbohydrates (WD), a high fat diet that induces obesity (DIO), or their respective control (CD) and standard (SD) diets for 16 weeks. Posterior cerebral arteries (PCAs) were isolated and pressurized for study. During acute exposure to H2O2 (200 µM), smooth muscle cell and endothelial cell death were reduced in PCAs from WD, but not DIO mice. WD selectively attenuated mitochondrial membrane potential depolarization and vessel wall Ca2+ influx during H2O2 exposure. Selective inhibition of transient receptor potential (TRP) V4 or TRPC3 channels reduced smooth muscle cell and endothelial cell death in concert with the vessel wall [Ca2+]i response to H2O2 for PCAs from CD mice and eliminated differences between CD and WD. Inhibiting Src kinases reduced smooth muscle cell death along with [Ca2+]i response to H2O2 only in PCAs from CD mice and eliminated differences between diets. However, Src kinase inhibition did not alter endothelial cell death. These findings indicate that consuming a WD, but not high fat alone, leads to adaptations that limit Ca2+ influx and vascular cell death during exposure to acute oxidative stress.
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Affiliation(s)
- Charles E Norton
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65212, USA
| | - Rebecca L Shaw
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65212, USA
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65212, USA
- Dalton Cardiovascular Research Center, Columbia, MO 65211, USA
- Department of Biomedical Sciences, University of Missouri, Columbia, MO 65201, USA
- Department of Biomedical, Biological and Chemical Engineering, University of Missouri, Columbia, MO 65211, USA
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65211, USA
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4
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Norton CE, Shaw RL, Mittler R, Segal SS. Endothelial cells promote smooth muscle cell resilience to H 2 O 2 -induced cell death in mouse cerebral arteries. Acta Physiol (Oxf) 2022; 235:e13819. [PMID: 35380737 DOI: 10.1111/apha.13819] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 03/28/2022] [Accepted: 03/31/2022] [Indexed: 12/01/2022]
Abstract
AIM Brain injury produces reactive oxygen species (ROS). However, little is known of how acute oxidative stress affects cell survival in the cerebral vascular supply. We hypothesized that endothelial cells (ECs) are more resilient to H2 O2 and protect vascular smooth muscle cells (SMCs) during acute oxidative stress. METHODS Mouse posterior cerebral arteries (PCAs; diameter, ~80 µm) were exposed to H2 O2 (200 µM, 50 min, 37°C). Nuclear staining identified dead and live cells of intact and endothelium-disrupted vessels. SMC [Ca2+ ]i was assessed with Fura-2 fluorescence, and superoxide production was assessed by dihydroethidium and MitoSOX fluorescence. RESULTS In response to H2 O2 : SMC death (21%) exceeded EC death (5%) and increased following endothelial disruption (to 48%) with a corresponding increase in SMC Ca2+ entry through transient receptor potential (TRP) channels. Whereas pharmacological inhibition of TRPV4 channels prevented SMC death and reduced Ca2+ entry for intact vessels, both remained elevated following endothelial disruption. In contrast, pharmacological inhibition or genetic deletion of TRPC3 prevented SMC death and attenuated Ca2+ entry for both intact and endothelium-disrupted vessels. Inhibiting gap junctions increased EC death (to 22%) while SMC death and [Ca2+ ]i responses were attenuated by inhibiting nitric oxide synthesis or scavenging superoxide/peroxynitrite. Inhibiting NADPH oxidases also prevented SMC Ca2+ entry and death. H2 O2 increased mitochondrial ROS production while scavenging mitochondria-derived superoxide prevented SMC death but not Ca2+ entry. CONCLUSIONS During acute exposure of cerebral arteries to acute oxidative stress, ECs are more resilient than SMCs and the endothelium may protect SMCs by reducing Ca2+ entry through TRPC3 channels.
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Affiliation(s)
- Charles E. Norton
- Department of Medical Pharmacology and Physiology University of Missouri Columbia Missouri USA
| | - Rebecca L. Shaw
- Department of Medical Pharmacology and Physiology University of Missouri Columbia Missouri USA
| | - Ron Mittler
- Department of Surgery University of Missouri Columbia Missouri USA
| | - Steven S. Segal
- Department of Medical Pharmacology and Physiology University of Missouri Columbia Missouri USA
- Dalton Cardiovascular Research Center Columbia Missouri USA
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Jacobsen NL, Norton CE, Shaw RL, Cornelison DDW, Segal SS. Myofibre injury induces capillary disruption and regeneration of disorganized microvascular networks. J Physiol 2022; 600:41-60. [PMID: 34761825 PMCID: PMC8965732 DOI: 10.1113/jp282292] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 11/09/2021] [Indexed: 01/03/2023] Open
Abstract
Injury to skeletal muscle disrupts myofibres and their microvascular supply. While the regeneration of myofibres is well described, little is known of how the microcirculation is affected by skeletal muscle injury or its recovery during regeneration. Nevertheless, the microvasculature must also recover to restore skeletal muscle function. We aimed to define the nature of microvascular damage and time course of repair during muscle injury and regeneration induced by the myotoxin BaCl2 . To test the hypothesis that microvascular disruption occurred secondary to myofibre injury, isolated microvessels were exposed to BaCl2 or the myotoxin was injected into the gluteus maximus (GM) muscle of mice. In isolated microvessels, BaCl2 depolarized smooth muscle cells (SMCs) and endothelial cells while increasing intracellular calcium in SMCs but did not elicit death of either cell type. At 1 day post-injury (dpi) of the GM, capillary fragmentation coincided with myofibre degeneration while arteriolar and venular networks remained intact; neutrophil depletion before injury did not prevent capillary damage. Perfused capillary networks reformed by 5 dpi in association with more terminal arterioles and were dilated through 10 dpi. With no change in microvascular area or branch point number in regenerating capillary networks, fewer capillaries aligned with myofibres and were no longer organized into microvascular units. By 21 dpi, capillary orientation and microvascular unit organization were no longer different from uninjured GM. We conclude that following their disruption secondary to myofibre damage, capillaries regenerate as disorganized networks that remodel into microvascular units as regenerated myofibres mature. KEY POINTS: Skeletal muscle regenerates after injury; however, the nature of microvascular damage and repair is poorly understood. Here, the myotoxin BaCl2 , a standard experimental method of acute skeletal muscle injury, was used to investigate the response of the microcirculation to local injury of intact muscle. Intramuscular injection of BaCl2 induced capillary fragmentation with myofibre degeneration; arteriolar and venular networks remained intact. Direct exposure to BaCl2 did not kill microvascular endothelial cells or smooth muscle cells. Dilated capillary networks reformed by 5 days post-injury (dpi) in association with more terminal arterioles. Capillary orientation remained disorganized through 10 dpi. Capillaries realigned with myofibres and reorganized into microvascular units by 21 dpi, which coincides with the recovery of vasomotor control and maturation of nascent myofibres. Skeletal muscle injury disrupts its capillary supply secondary to myofibre degeneration. Reorganization of regenerating microvascular networks accompanies the recovery of blood flow regulation.
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Affiliation(s)
- Nicole L. Jacobsen
- Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | - Charles E. Norton
- Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | - Rebecca L. Shaw
- Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | - D. D. W. Cornelison
- Biological Sciences, University of Missouri, Columbia, MO, USA,Christopher S. Bond Life Sciences Center, University of MO, Columbia, MO, USA
| | - Steven S. Segal
- Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA,Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
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6
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Harraz OF, Jensen LJ. Vascular calcium signalling and ageing. J Physiol 2021; 599:5361-5377. [PMID: 34705288 PMCID: PMC9002240 DOI: 10.1113/jp280950] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 10/12/2021] [Indexed: 02/05/2023] Open
Abstract
Changes in cellular Ca2+ levels have major influences on vascular function and blood pressure regulation. Vascular smooth muscle cells (SMCs) and endothelial cells (ECs) orchestrate vascular activity in distinct ways, often involving highly specific fluctuations in Ca2+ signalling. Ageing is a major risk factor for cardiovascular diseases, but the impact of ageing per se on vascular Ca2+ signalling has received insufficient attention. We reviewed the literature for age-related changes in Ca2+ signalling in relation to vascular structure and function. Vascular tone dysregulation in several vascular beds has been linked to abnormal expression or activity of SMC voltage-gated Ca2+ channels, Ca2+ -activated K+ channels or TRPC6 channels. Some of these effects were linked to altered caveolae density, microRNA expression or 20-HETE abundance. Intracellular store Ca2+ handling was suppressed in ageing mainly via reduced expression of intracellular Ca2+ release channels, and Ca2+ reuptake or efflux pumps. An increase in mitochondrial Ca2+ uptake, leading to oxidative stress, could also play a role in SMC hypercontractility and structural remodelling in ageing. In ECs, ageing entailed diverse effects on spontaneous and evoked Ca2+ transients, as well as structural changes at the EC-SMC interface. The concerted effects of altered Ca2+ signalling on myogenic tone, endothelium-dependent vasodilatation, and vascular structure are likely to contribute to blood pressure dysregulation and blood flow distribution deficits in critical organs. With the increase in the world's ageing population, future studies should be directed at solving specific ageing-induced Ca2+ signalling deficits to combat the imminent accelerated vascular ageing and increased risk of cardiovascular diseases.
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Affiliation(s)
- Osama F. Harraz
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, Vermont, USA,Vermont Center for Cardiovascular and Brain Health, University of Vermont, Burlington, Vermont, USA
| | - Lars Jørn Jensen
- Pathobiological Sciences, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
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Shaw RL, Norton CE, Segal SS. Apoptosis in resistance arteries induced by hydrogen peroxide: greater resilience of endothelium versus smooth muscle. Am J Physiol Heart Circ Physiol 2021; 320:H1625-H1633. [PMID: 33606587 DOI: 10.1152/ajpheart.00956.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Reactive oxygen species (ROS) are implicated in cardiovascular and neurologic disorders including atherosclerosis, heart attack, stroke, and traumatic brain injury. Although oxidative stress can lead to apoptosis of vascular cells, such findings are largely based upon isolated vascular smooth muscle cells (SMCs) and endothelial cells (ECs) studied in culture. Studying intact resistance arteries, we have focused on understanding how SMCs and ECs in the blood vessel wall respond to acute oxidative stress induced by hydrogen peroxide, a ubiquitous, membrane-permeant ROS. We find that apoptosis induced by H2O2 is far greater in SMCs compared to ECs. For both cell types, apoptosis is associated with a rise in intracellular calcium concentration ([Ca2+]i) during H2O2 exposure. Consistent with their greater death, the rise in [Ca2+]i for SMCs exceeds that in ECs. Finding that disruption of the endothelium increases SMC death, we address how myoendothelial coupling and paracrine signaling attenuate apoptosis. Remarkably, conditions associated with chronic oxidative stress (advanced age, Western-style diet) protect SMCs during H2O2 exposure, as does female sex. In light of intracellular Ca2+ handling, we consider how glycolytic versus oxidative pathways for ATP production and changes in mitochondrial structure and function impact cellular resilience to H2O2-induced apoptosis. Gaining new insight into protective signaling within and between SMCs and ECs of the arterial wall can be applied to promote vascular cell survival (and recovery of blood flow) in tissues subjected to acute oxidative stress as occurs during reperfusion following myocardial infarction and thrombotic stroke.
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Affiliation(s)
- Rebecca L Shaw
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Charles E Norton
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri.,Dalton Cardiovascular Research Center, Columbia, Missouri
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Hakim MA, Chum PP, Buchholz JN, Behringer EJ. Aging Alters Cerebrovascular Endothelial GPCR and K+ Channel Function: Divergent Role of Biological Sex. J Gerontol A Biol Sci Med Sci 2021; 75:2064-2073. [PMID: 31760422 DOI: 10.1093/gerona/glz275] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Indexed: 12/11/2022] Open
Abstract
Age-related dementia entails impaired blood flow to and throughout the brain due, in part, to reduced endothelial nitric oxide signaling. However, it is unknown whether sex affects cerebrovascular Gq-protein-coupled receptors (GPCRs) and K+ channels underlying endothelium-derived hyperpolarization (EDH) during progressive aging. Thus, we simultaneously evaluated intracellular Ca2+ ([Ca2+]i) and membrane potential (Vm) of intact endothelial tubes freshly isolated from posterior cerebral arteries of young (4-6 mo), middle-aged (12-16 mo), and old (24-28 mo) male and female C57BL/6 mice. Purinergic receptor function (vs. muscarinic) was dominant and enhanced for [Ca2+]i increases in old females versus old males. However, Ca2+-sensitive K+ channel function as defined by NS309-evoked Vm hyperpolarization was mildly impaired in females versus males during old age. This sex-based contrast in declined function of GPCRs and K+ channels to produce EDH may support a greater ability for physiological endothelial GPCR function to maintain optimal cerebral blood flow in females versus males during old age. As reflective of the pattern of cerebral blood flow decline in human subjects, inward-rectifying K+ (KIR) channel function decreased with progressive age regardless of sex. Combined age-related analyses masked male versus female aging and, contrary to expectation, hydrogen peroxide played a minimal role. Altogether, we conclude a sex-based divergence in cerebrovascular endothelial GPCR and K+ channel function while highlighting a previously unidentified form of age-related endothelial dysfunction as reduced KIR channel function.
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Affiliation(s)
- Md A Hakim
- Basic Sciences, Loma Linda University, California
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Abstract
Sleep maintains the function of the entire body through homeostasis. Chronic sleep deprivation (CSD) is a prime health concern in the modern world. Previous reports have shown that CSD has profound negative effects on brain vasculature at both the cellular and molecular levels, and that this is a major cause of cognitive dysfunction and early vascular ageing. However, correlations among sleep deprivation (SD), brain vascular changes and ageing have barely been looked into. This review attempts to correlate the alterations in the levels of major neurotransmitters (acetylcholine, adrenaline, GABA and glutamate) and signalling molecules (Sirt1, PGC1α, FOXO, P66shc, PARP1) in SD and changes in brain vasculature, cognitive dysfunction and early ageing. It also aims to connect SD-induced loss in the number of dendritic spines and their effects on alterations in synaptic plasticity, cognitive disabilities and early vascular ageing based on data available in scientific literature. To the best of our knowledge, this is the first article providing a pathophysiological basis to link SD to brain vascular ageing.
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10
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Biwer LA, Askew-Page HR, Hong K, Milstein J, Johnstone SR, Macal E, Good ME, Bagher P, Sonkusare SK, Isakson BE. Endothelial calreticulin deletion impairs endothelial function in aged mice. Am J Physiol Heart Circ Physiol 2020; 318:H1041-H1048. [PMID: 32196361 PMCID: PMC7346539 DOI: 10.1152/ajpheart.00586.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Discrete calcium signals within the vascular endothelium decrease with age and contribute to impaired endothelial-dependent vasodilation. Calreticulin (Calr), a multifunctional calcium binding protein and endoplasmic reticulum (ER) chaperone, can mediate calcium signals and vascular function within the endothelial cells (ECs) of small resistance arteries. We found Calr protein expression significantly decreases with age in mesenteric arteries and examined the functional role of EC Calr in vasodilation and calcium mobilization in the context of aging. Third-order mesenteric arteries from mice with or without EC Calr knockdown were examined for calcium signals and constriction to phenylephrine (PE) or vasodilation to carbachol (CCh) after 75 wk of age. PE constriction in aged mice with or without EC Calr was unchanged. However, calcium signals and vasodilation to endothelial-dependent agonist carbachol were significantly impaired in aged EC Calr knockdown mice. Ex vivo incubation of arteries with the ER stress inhibitor tauroursodeoxycholic acid (TUDCA) significantly improved vasodilation in mice lacking EC Calr. Our data suggests diminished vascular Calr expression with age can contribute to the detrimental effects of aging on endothelial calcium regulation and vasodilation.NEW & NOTEWORTHY Calreticulin (Calr) is responsible for key physiological processes in endoplasmic reticulum, especially in aging tissue. In particular, endothelial Calr is crucial to vascular function. In this study, we deleted Calr from the endothelium and aged the mice up to 75 wk to examine changes in vascular function. We found two key differences: 1) calcium events in endothelium were severely diminished after muscarinic stimulation, which 2) corresponded with a dramatic decrease in muscarinic vasodilation. Remarkably, we were able to rescue the effect of Calr deletion on endothelial-dependent vasodilatory function using tauroursodeoxycholic acid (TUDCA), an inhibitor of endoplasmic reticulum stress that is currently in clinical trials.
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Affiliation(s)
- Lauren A Biwer
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia.,Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia.,Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts
| | - Henry R Askew-Page
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia.,Vascular Biology Research Centre, Institute of Molecular and Clinical Sciences, St. George's University of London, London, United Kingdom
| | - Kwangseok Hong
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia.,Department of Physical Education, College of Education, Chung-Ang University, Seoul, South Korea
| | - Jenna Milstein
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Scott R Johnstone
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Edgar Macal
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Miranda E Good
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia.,Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts
| | - Pooneh Bagher
- Department of Medical Physiology, Texas A&M University Health Science Center, Bryan, Texas
| | - Swapnil K Sonkusare
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia.,Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia.,Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia
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11
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Norton CE, Jacobsen NL, Sinkler SY, Manrique-Acevedo C, Segal SS. Female sex and Western-style diet protect mouse resistance arteries during acute oxidative stress. Am J Physiol Cell Physiol 2019; 318:C627-C639. [PMID: 31891519 DOI: 10.1152/ajpcell.00342.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A Western-style diet (WD; high in fat and carbohydrates) increases vascular oxidative stress. We hypothesized that vascular cells adapt to a WD by developing resilience to oxidative stress. Male and female C57BL/6J mice (4 wk of age) were fed a control diet (CD) or a WD for 16-20 wk. Superior epigastric arteries (SEAs; diameter, ~125 µm) were isolated and pressurized for study. Basal reactive oxygen species production was greatest in SEAs from males fed the WD. During exposure to H2O2 (200 μM, 50 min), propidium iodide staining identified nuclei of disrupted endothelial cells (ECs) and smooth muscle cells (SMCs). For mice fed the CD, death of SMCs (21%) and ECs (6%) was greater (P < 0.05) in SEAs from males than females (9% and 2%, respectively). WD consumption attenuated cell death most effectively in SEAs from males. With no difference at rest, H2O2 increased intracellular Ca2+ concentration ([Ca2+]i) to the greatest extent in SEAs from males, as shown by fura 2 fluorescence. Selective disruption of the endothelium (luminal air bubble) increased [Ca2+]i and SMC death during H2O2 exposure irrespective of sex; the WD reduced both responses most effectively in males. Nonselective transient receptor potential (TRP) channel inhibition (ruthenium red, 5 μM) attenuated the rise of [Ca2+]i, as did selective inhibition of TRP vanilloid type 4 (TRPV4) channels (HC-067047, 1 μM), which also attenuated cell death. In contrast, inhibition of voltage-gated Ca2+ channels (diltiazem, 50 μM) was without effect. Thus, for resistance arteries during acute oxidative stress: 1) ECs are more resilient than (and can protect) SMCs, 2) vessels from females are inherently more resilient than those from males, and 3) a WD increases vascular resilience by diminishing TRPV4 channel-dependent Ca2+ entry.
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Affiliation(s)
- Charles E Norton
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Nicole L Jacobsen
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Shenghua Y Sinkler
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Camila Manrique-Acevedo
- Department of Medicine, University of Missouri, Columbia, Missouri.,Research Services, Harry S Truman Memorial Veterans Hospital, Columbia, Missouri.,Dalton Cardiovascular Research Center, Columbia, Missouri
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri.,Dalton Cardiovascular Research Center, Columbia, Missouri
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12
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Morton AB, Norton CE, Jacobsen NL, Fernando CA, Cornelison DDW, Segal SS. Barium chloride injures myofibers through calcium-induced proteolysis with fragmentation of motor nerves and microvessels. Skelet Muscle 2019; 9:27. [PMID: 31694693 PMCID: PMC6833148 DOI: 10.1186/s13395-019-0213-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 09/30/2019] [Indexed: 12/15/2022] Open
Abstract
Background Local injection of BaCl2 is an established model of acute injury to study the regeneration of skeletal muscle. However, the mechanism by which BaCl2 causes muscle injury is unresolved. Because Ba2+ inhibits K+ channels, we hypothesized that BaCl2 induces myofiber depolarization leading to Ca2+ overload, proteolysis, and membrane disruption. While BaCl2 spares resident satellite cells, its effect on other tissue components integral to contractile function has not been defined. We therefore asked whether motor nerves and microvessels, which control and supply myofibers, are injured by BaCl2 treatment. Methods The intact extensor digitorum longus (EDL) muscle was isolated from male mice (aged 3–4 months) and irrigated with physiological salt solution (PSS) at 37 °C. Myofiber membrane potential (Vm) was recorded using sharp microelectrodes while intracellular calcium concentration ([Ca2+]i) was evaluated with Fura 2 dye. Isometric force production of EDL was measured in situ, proteolytic activity was quantified by calpain degradation of αII-spectrin, and membrane disruption was marked by nuclear staining with propidium iodide (PI). To test for effects on motor nerves and microvessels, tibialis anterior or gluteus maximus muscles were injected with 1.2% BaCl2 (50–75 μL) in vivo followed by immunostaining to evaluate the integrity of respective tissue elements post injury. Data were analyzed using Students t test and analysis of variance with P ≤ 0.05 considered statistically significant. Results Addition of 1.2% BaCl2 to PSS depolarized myofibers from − 79 ± 3 mV to − 17 ± 7 mV with a corresponding rise in [Ca2+]i; isometric force transiently increased from 7.4 ± 0.1 g to 11.1 ± 0.4 g. Following 1 h of BaCl2 exposure, 92 ± 3% of myonuclei stained with PI (vs. 8 ± 3% in controls) with enhanced cleavage of αII-spectrin. Eliminating Ca2+ from PSS prevented the rise in [Ca2+]i and ameliorated myonuclear staining with PI during BaCl2 exposure. Motor axons and capillary networks appeared fragmented within 24 h following injection of 1.2% BaCl2 and morphological integrity deteriorated through 72 h. Conclusions BaCl2 injures myofibers through depolarization of the sarcolemma, causing Ca2+ overload with transient contraction, leading to proteolysis and membrane rupture. Motor innervation and capillarity appear disrupted concomitant with myofiber damage, further compromising muscle integrity.
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Affiliation(s)
- Aaron B Morton
- Department of Medical Pharmacology and Physiology, University of Missouri, MA415 Medical Sciences Building, 1 Hospital Drive, Columbia, MO, 65212, USA
| | - Charles E Norton
- Department of Medical Pharmacology and Physiology, University of Missouri, MA415 Medical Sciences Building, 1 Hospital Drive, Columbia, MO, 65212, USA
| | - Nicole L Jacobsen
- Department of Medical Pharmacology and Physiology, University of Missouri, MA415 Medical Sciences Building, 1 Hospital Drive, Columbia, MO, 65212, USA
| | - Charmain A Fernando
- Department of Medical Pharmacology and Physiology, University of Missouri, MA415 Medical Sciences Building, 1 Hospital Drive, Columbia, MO, 65212, USA
| | - D D W Cornelison
- Division of Biological Sciences and Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, 65201, USA
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri, MA415 Medical Sciences Building, 1 Hospital Drive, Columbia, MO, 65212, USA. .,Dalton Cardiovascular Research Center, Columbia, MO, 65211, USA.
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