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Tang C, Border JJ, Zhang H, Gregory A, Bai S, Fang X, Liu Y, Wang S, Hwang SH, Gao W, Morgan GC, Smith J, Bunn D, Cantwell C, Wagner KM, Morisseau C, Yang J, Shin SM, O'Herron P, Bagi Z, Filosa JA, Dong Y, Yu H, Hammock BD, Roman RJ, Fan F. Inhibition of Soluble Epoxide Hydrolase Ameliorates Cerebral Blood Flow Autoregulation and Cognition in Alzheimer's Disease and Diabetes-Related Dementia Rat Models. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.30.610540. [PMID: 39257786 PMCID: PMC11383657 DOI: 10.1101/2024.08.30.610540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2024]
Abstract
Alzheimer's Disease and Alzheimer's Disease-related dementias (AD/ADRD) pose major global healthcare challenges, with diabetes mellitus (DM) being a key risk factor. Both AD and DM-related ADRD are characterized by reduced cerebral blood flow, although the exact mechanisms remain unclear. We previously identified compromised cerebral hemodynamics as early signs in TgF344-AD and type 2 DM-ADRD (T2DN) rat models. Genome-wide studies have linked AD/ADRD to SNPs in soluble epoxide hydrolase (sEH). This study explored the effects of sEH inhibition with TPPU on cerebral vascular function and cognition in AD and DM-ADRD models. Chronic TPPU treatment improved cognition in both AD and DM-ADRD rats without affecting body weight. In DM-ADRD rats, TPPU reduced plasma glucose and HbA1C levels. Transcriptomic analysis of primary cerebral vascular smooth muscle cells from AD rats treated with TPPU revealed enhanced pathways related to cell contraction, alongside decreased oxidative stress and inflammation. Both AD and DM-ADRD rats exhibited impaired myogenic responses and autoregulation in the cerebral circulation, which were normalized with chronic sEH inhibition. Additionally, TPPU improved acetylcholine-induced vasodilation in the middle cerebral arteries (MCA) of DM-ADRD rats. Acute TPPU administration unexpectedly caused vasoconstriction in the MCA of DM-ADRD rats at lower doses. In contrast, higher doses or longer durations were required to induce effective vasodilation at physiological perfusion pressure in both control and ADRD rats. Additionally, TPPU decreased reactive oxygen species production in cerebral vessels of AD and DM-ADRD rats. These findings provide novel evidence that chronic sEH inhibition can reverse cerebrovascular dysfunction and cognitive impairments in AD/ADRD, offering a promising avenue for therapeutic development.
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Affiliation(s)
- Chengyun Tang
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS
| | - Jane J Border
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS
| | - Huawei Zhang
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS
| | - Andrew Gregory
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
| | - Shan Bai
- Center for Biotechnology and Genomic Medicine, Medical College of Georgia, Augusta University, Augusta, GA
| | - Xing Fang
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS
| | - Yedan Liu
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS
| | - Shaoxun Wang
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS
| | - Sung Hee Hwang
- Entomology and Nematology and UC Davis Comprehensive Cancer Center, University of California Davis, Davis, CA
| | - Wenjun Gao
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS
| | - Gilbert C Morgan
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
| | - Jhania Smith
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
| | - David Bunn
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
| | - Cameron Cantwell
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
| | - Karen M Wagner
- Entomology and Nematology and UC Davis Comprehensive Cancer Center, University of California Davis, Davis, CA
| | - Christophe Morisseau
- Entomology and Nematology and UC Davis Comprehensive Cancer Center, University of California Davis, Davis, CA
| | - Jun Yang
- Entomology and Nematology and UC Davis Comprehensive Cancer Center, University of California Davis, Davis, CA
| | - Seung Min Shin
- Anesthesiology, Medical College of Wisconsin, Milwaukee, WI
| | - Philip O'Herron
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
| | - Zsolt Bagi
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
| | - Jessica A Filosa
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
| | - Yanbin Dong
- Georgia Prevention Center, Augusta University, Augusta, GA
| | - Hongwei Yu
- Anesthesiology, Medical College of Wisconsin, Milwaukee, WI
| | - Bruce D Hammock
- Entomology and Nematology and UC Davis Comprehensive Cancer Center, University of California Davis, Davis, CA
| | - Richard J Roman
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
| | - Fan Fan
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS
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Polk FD, Hakim MA, Silva JF, Behringer EJ, Pires PW. Endothelial K IR2 channel dysfunction in aged cerebral parenchymal arterioles. Am J Physiol Heart Circ Physiol 2023; 325:H1360-H1372. [PMID: 37801044 PMCID: PMC10907073 DOI: 10.1152/ajpheart.00279.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 09/27/2023] [Accepted: 09/28/2023] [Indexed: 10/07/2023]
Abstract
Aging is associated with cognitive decline via incompletely understood mechanisms. Cerebral microvascular dysfunction occurs in aging, particularly impaired endothelium-mediated dilation. Parenchymal arterioles are bottlenecks of the cerebral microcirculation, and dysfunction causes a mismatch in nutrient demand and delivery, leaving neurons at risk. Extracellular nucleotides elicit parenchymal arteriole dilation by activating endothelial purinergic receptors (P2Y), leading to opening of K+ channels, including inwardly-rectifying K+ channels (KIR2). These channels amplify hyperpolarizing signals, resulting in dilation. However, it remains unknown if endothelial P2Y and KIR2 signaling are altered in brain parenchymal arterioles during aging. We hypothesized that aging impairs endothelial P2Y and KIR2 function in parenchymal arterioles. We observed reduced dilation to the purinergic agonist 2-methyl-S-ADP (1 µM) in arterioles from Aged (>24-month-old) mice when compared to Young (4-6 months of age) despite similar hyperpolarization in endothelial cells tubes. No differences were observed in vasodilation or endothelial cell hyperpolarization to activation of small- and intermediate-conductance Ca2+-activated K+ channels (KCa2.3 / KCa3.1) by NS309. Hyperpolarization to 15 mM [K+]E was smaller in Aged than Young mice, despite a paradoxical increased dilation in Aged arterioles to 15 mM [K+]E that was unchanged by endothelium removal. KIR2 Inhibition attenuated vasodilatory responses to 15 mM [K+]E and 1 µM 2-me-S-ADP in both Young and Aged arterioles. Further, we observed a significant increase in myogenic tone in Aged parenchymal arterioles, which was not enhanced by endothelium removal. We conclude that aging impairs endothelial KIR2 channel function in the cerebral microcirculation with possible compensation by smooth muscle cells.
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Affiliation(s)
- Felipe D Polk
- Department of Physiology, University of Arizona, Tucson, Arizona, United States
| | - Md A Hakim
- Loma Linda University, Loma Linda, CA, United States
| | - Josiane F Silva
- Physiology, University of Arizona, Tucson, Arizona, United States
| | - Erik J Behringer
- Basic Sciences, Loma Linda University, Loma Linda, CA, United States
| | - Paulo W Pires
- Physiology, University of Arizona, Tucson, AZ, United States
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Jeffrey DA, Russell A, Guerrero MB, Fontaine JT, Romero P, Rosehart AC, Dabertrand F. Estrogen regulates myogenic tone in hippocampal arterioles by enhanced basal release of nitric oxide and endothelial SK Ca channel activity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.15.553442. [PMID: 37645715 PMCID: PMC10462022 DOI: 10.1101/2023.08.15.553442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Arteries and arterioles exhibit myogenic tone, a partially constricted state that allows further constriction or dilation in response to moment-to-moment fluctuations in blood pressure. The vascular endothelium that lines the internal surface of all blood vessels controls a wide variety of essential functions, including the contractility of the adjacent smooth muscle cells by providing a tonic vasodilatory influence. Studies conducted on large (pial) arteries on the surface of the brain have shown that estrogen lowers myogenic tone in female mice by enhancing nitric oxide (NO) release from the endothelium, however, whether this difference extends to the intracerebral microcirculation remains ambiguous. The existing incomplete picture of sex differences in cerebrovascular physiology combined with a deficiency in treatments that fully restore cognitive function after cerebrovascular accidents places heavy emphasis on the necessity to investigate myogenic tone regulation in the microcirculation from both male and female mice. We hypothesized that sex-linked hormone regulation of myogenic tone extends its influence on the microcirculation level, and sought to characterize it in isolated arterioles from the hippocampus, a major cognitive brain area. Using diameter measurements both in vivo (acute cranial window vascular diameter) and ex vivo (pressure myography experiments), we measured lower myogenic tone responses in hippocampal arterioles from female than male mice. By using a combined surgical and pharmacological approach, we found myogenic tone in ovariectomized (OVX) female mice matches that of males, as well as in endothelium-denuded arterioles. Interestingly, eNOS inhibition induced a larger constriction in female arterioles but only partially abolished the difference in tone. We identified that the remnant difference was mediated by a higher activity and expression of the small-conductance Ca 2+ -sensitive K + (SK) channels. Collectively, these data indicate that eNOS and SK channels exert greater vasodilatory influence over myogenic tone in female mice at physiological pressures.
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Fang X, Tang C, Zhang H, Border JJ, Liu Y, Shin SM, Yu H, Roman RJ, Fan F. Longitudinal characterization of cerebral hemodynamics in the TgF344-AD rat model of Alzheimer's disease. GeroScience 2023; 45:1471-1490. [PMID: 36933144 PMCID: PMC10400494 DOI: 10.1007/s11357-023-00773-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 03/12/2023] [Indexed: 03/19/2023] Open
Abstract
Alzheimer's disease (AD) is a global healthcare crisis. The TgF344-AD rat is an AD model exhibiting age-dependent AD pathological hallmarks. We confirmed that AD rats developed cognitive deficits at 6 months without alteration of any other major biophysical parameters. We longitudinally characterized cerebral hemodynamics in AD rats at 3, 4, 6, and 14 months. The myogenic responses of the cerebral arteries and arterioles were impaired at 4 months of age in the AD rats. Consistent with the ex vivo results, the AD rat exhibited poor autoregulation of surface and deep cortical cerebral blood flow 2 months preceding cognitive decline. The dysfunction of cerebral hemodynamics in AD is exacerbated with age associated with reduced cerebral perfusion. Further, abolished cell contractility contributes to cerebral hemodynamics imbalance in AD. This may be attributed to enhanced ROS production, reduced mitochondrial respiration and ATP production, and disrupted actin cytoskeleton in cerebral vascular contractile cells.
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Affiliation(s)
- Xing Fang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Chengyun Tang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
- Department of Physiology, Medical College of Georgia, Augusta University, 1462 Laney Walker Blvd, Augusta, GA, 30912, USA
| | - Huawei Zhang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Jane J Border
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Yedan Liu
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Seung Min Shin
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI, 53226, USA
| | - Hongwei Yu
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI, 53226, USA
| | - Richard J Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA.
- Department of Physiology, Medical College of Georgia, Augusta University, 1462 Laney Walker Blvd, Augusta, GA, 30912, USA.
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Zhang H, Border JJ, Fang X, Liu Y, Tang C, Gao W, Wang S, Shin SM, Guo Y, Zhang C, Gonzalez-Fernandez E, Yu H, Sun P, Roman RJ, Fan F. Enhanced Cerebral Hemodynamics and Cognitive Function Via Knockout of Dual-Specificity Protein Phosphatase 5. JOURNAL OF PHARMACY AND PHARMACOLOGY RESEARCH 2023; 7:49-61. [PMID: 37588944 PMCID: PMC10430881 DOI: 10.26502/fjppr.070] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 08/18/2023]
Abstract
Alzheimer's Disease (AD) and Alzheimer's Disease-Related Dementias (ADRD) are neurodegenerative disorders. Recent studies suggest that cerebral hypoperfusion is an early symptom of AD/ADRD. Dual-specificity protein phosphatase 5 (DUSP5) has been implicated in several pathological conditions, including pulmonary hypertension and cancer, but its role in AD/ADRD remains unclear. The present study builds on our previous findings, demonstrating that inhibition of ERK and PKC leads to a dose-dependent dilation of the middle cerebral artery and penetrating arteriole, with a more pronounced effect in Dusp5 KO rats. Both ERK and PKC inhibitors resulted in a significant reduction of myogenic tone in vessels from Dusp5 KO rats. Dusp5 KO rats exhibited stronger autoregulation of the surface but not deep cortical cerebral blood flow. Inhibition of ERK and PKC significantly enhanced the contractile capacity of vascular smooth muscle cells from both strains. Finally, a significant improvement in learning and memory was observed in Dusp5 KO rats 24 hours after initial training. Our results suggest that altered vascular reactivity in Dusp5 KO rats may involve distinct mechanisms for different vascular beds, and DUSP5 deletion could be a potential therapeutic target for AD/ADRD. Further investigations are necessary to determine the effects of DUSP5 inhibition on capillary stalling, blood-brain barrier permeability, and neurodegeneration in aging and disease models.
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Affiliation(s)
- Huawei Zhang
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
- Neurosurgery, Affiliated Hospital of Qingdao University, Qingdao, China
| | - Jane J Border
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Xing Fang
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Yedan Liu
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Chengyun Tang
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Wenjun Gao
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Shaoxun Wang
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Seung Min Shin
- Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Ya Guo
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Chao Zhang
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | | | - Hongwei Yu
- Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Peng Sun
- Neurosurgery, Affiliated Hospital of Qingdao University, Qingdao, China
| | - Richard J Roman
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Fan Fan
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA, USA
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Blackwell JA, Silva JF, Louis EM, Savu A, Largent-Milnes TM, Brooks HL, Pires PW. Cerebral arteriolar and neurovascular dysfunction after chemically induced menopause in mice. Am J Physiol Heart Circ Physiol 2022; 323:H845-H860. [PMID: 36149767 PMCID: PMC9602916 DOI: 10.1152/ajpheart.00276.2022] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 09/20/2022] [Accepted: 09/20/2022] [Indexed: 12/14/2022]
Abstract
Cognitive decline is linked to decreased cerebral blood flow, particularly in women after menopause. Impaired cerebrovascular function precedes the onset of dementia, possibly because of reduced functional dilation in parenchymal arterioles. These vessels are bottlenecks of the cerebral microcirculation, and dysfunction can limit functional hyperemia in the brain. Large-conductance Ca2+-activated K+ channels (BKCa) are the final effectors of several pathways responsible for functional hyperemia, and their expression is modulated by estrogen. However, it remains unknown whether BKCa function is altered in cerebral parenchymal arterioles after menopause. Using a chemically induced model of menopause, the 4-vinylcyclohexene diepoxide (VCD) model, which depletes follicles while maintaining intact ovaries, we hypothesized that menopause would be associated with reduced functional vasodilatory responses in cerebral parenchymal arterioles of wild-type mice via reduced BKCa function. Using pressure myography of isolated parenchymal arterioles, we observed that menopause (Meno) induced a significant increase in spontaneous myogenic tone. Endothelial function, assessed as nitric oxide production and dilation after cholinergic stimulation or endothelium-dependent hyperpolarization pathways, was unaffected by Meno. BKCa function was significantly impaired in Meno compared with control, without changes in voltage-gated K+ channel activity. Cerebral functional hyperemia, measured by laser-speckle contrast imaging during whisker stimulation, was significantly blunted in Meno mice, without detectable changes in basal perfusion. However, behavioral testing identified no change in cognition. These findings suggest that menopause induces cerebral microvascular and neurovascular deficits.NEW & NOTEWORTHY Cerebral parenchymal arterioles from menopause mice showed increased myogenic tone. We identified an impairment in smooth muscle cell BKCa channel activity, without a reduction in endothelium-dependent dilation or nitric oxide production. Microvascular dysfunction was associated with a reduction in neurovascular responses after somatosensory stimulation. Despite the neurovascular impairment, cognitive abilities were maintained in menopausal mice.
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Affiliation(s)
- Jade A Blackwell
- Department of Physiology, University of Arizona, Tucson, Arizona
| | - Josiane F Silva
- Department of Physiology, University of Arizona, Tucson, Arizona
| | - Emma M Louis
- Department of Physiology, University of Arizona, Tucson, Arizona
| | - Andrea Savu
- Department of Physiology, University of Arizona, Tucson, Arizona
| | - Tally M Largent-Milnes
- Department of Pharmacology, University of Arizona, Tucson, Arizona
- Bio5 Institute, University of Arizona, Tucson, Arizona
| | - Heddwen L Brooks
- Department of Physiology, University of Arizona, Tucson, Arizona
- Bio5 Institute, University of Arizona, Tucson, Arizona
- Sarver Heart Center, University of Arizona, Tucson, Arizona
| | - Paulo W Pires
- Department of Physiology, University of Arizona, Tucson, Arizona
- Bio5 Institute, University of Arizona, Tucson, Arizona
- Sarver Heart Center, University of Arizona, Tucson, Arizona
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Hakim MA, Pires PW, Behringer EJ. Isolation and Functional Analysis of Arteriolar Endothelium of Mouse Brain Parenchyma. JOURNAL OF VISUALIZED EXPERIMENTS : JOVE 2022:10.3791/63463. [PMID: 35343953 PMCID: PMC9154351 DOI: 10.3791/63463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cerebral blood flow is conveyed by vascular resistance arteries and downstream parenchymal arterioles. Steady-state vascular resistance to blood flow increases with decreasing diameter from arteries to arterioles that ultimately feed into capillaries. Due to their smaller size and location in the parenchyma, arterioles have been relatively understudied and with less reproducibility in findings than surface pial arteries. Regardless, arteriolar endothelial cell structure and function-integral to the physiology and etiology of chronic degenerative diseases-requires extensive investigation. In particular, emerging evidence demonstrates that compromised endothelial function precedes and exacerbates cognitive impairment and dementia. In the parenchymal microcirculation, endothelial K+ channel function is the most robust stimulus to finely control the spread of vasodilation to promote increases in blood flow to areas of neuronal activity. This paper illustrates a refined method for freshly isolating intact and electrically coupled endothelial "tubes" (diameter, ~25 µm) from mouse brain parenchymal arterioles. Arteriolar endothelial tubes are secured during physiological conditions (37 °C, pH 7.4) to resolve experimental variables that encompass K+ channel function and their regulation, including intracellular Ca2+ dynamics, changes in membrane potential, and membrane lipid regulation. A distinct technical advantage versus arterial endothelium is the enhanced morphological resolution of cell and organelle (e.g., mitochondria) dimensions, which expands the usefulness of this technique. Healthy cerebral perfusion throughout life entails robust endothelial function in parenchymal arterioles, directly linking blood flow to the fueling of neuronal and glial activity throughout precise anatomical regions of the brain. Thus, it is expected that this method will significantly advance the general knowledge of vascular physiology and neuroscience concerning the healthy and diseased brain.
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Affiliation(s)
- Md A. Hakim
- Department of Basic Sciences, Loma Linda University
| | - Paulo W. Pires
- Departments of Physiology, Surgery and Neurosurgery and Sarver Heart Center, University of Arizona College of Medicine Tucson
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Liu Y, Zhang H, Wu CY, Yu T, Fang X, Ryu JJ, Zheng B, Chen Z, Roman RJ, Fan F. 20-HETE-promoted cerebral blood flow autoregulation is associated with enhanced pericyte contractility. Prostaglandins Other Lipid Mediat 2021; 154:106548. [PMID: 33753221 PMCID: PMC8154705 DOI: 10.1016/j.prostaglandins.2021.106548] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/03/2021] [Accepted: 03/10/2021] [Indexed: 12/22/2022]
Abstract
We previously reported that deficiency in 20-HETE or CYP4A impaired the myogenic response and autoregulation of cerebral blood flow (CBF) in rats. The present study demonstrated that CYP4A was coexpressed with alpha-smooth muscle actin (α-SMA) in vascular smooth muscle cells (VSMCs) and most pericytes along parenchymal arteries (PAs) isolated from SD rats. Cell contractile capabilities of cerebral VSMCs and pericytes were reduced with a 20-HETE synthesis inhibitor, HET0016, but restored with 20-HETE analog WIT003. Similarly, intact myogenic responses of the middle cerebral artery and PA of SD rats decreased with HET0016 and were rescued by WIT003. The myogenic response of the PA was abolished in SS and was restored in SS.BN5 and SS.Cyp4a1 rats. HET0016 enhanced CBF and impaired its autoregulation in the surface and deep cortex of SD rats. These results demonstrate that 20-HETE has a direct effect on cerebral mural cell contractility that may play an essential role in controlling cerebral vascular function.
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Affiliation(s)
- Yedan Liu
- Department of Pediatrics, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, 266003, China; Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Huawei Zhang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Celeste Yc Wu
- Department of Neurology, Louisiana State University Health Sciences Center, Shreveport, LA, 71130, USA
| | - Tina Yu
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Xing Fang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Jane J Ryu
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Baoying Zheng
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Zongbo Chen
- Department of Pediatrics, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, 266003, China
| | - Richard J Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, 39216, USA.
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Liu Y, Zhang H, Wang S, Guo Y, Fang X, Zheng B, Gao W, Yu H, Chen Z, Roman RJ, Fan F. Reduced pericyte and tight junction coverage in old diabetic rats are associated with hyperglycemia-induced cerebrovascular pericyte dysfunction. Am J Physiol Heart Circ Physiol 2021; 320:H549-H562. [PMID: 33306445 PMCID: PMC8082790 DOI: 10.1152/ajpheart.00726.2020] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/22/2020] [Accepted: 11/13/2020] [Indexed: 12/16/2022]
Abstract
Diabetes mellitus (DM) is one of the primary pathological factors that contributes to aging-related cognitive impairments, but the underlying mechanisms remain unclear. We recently reported that old DM rats exhibited impaired myogenic responses of the cerebral arteries and arterioles, poor cerebral blood flow autoregulation, enhanced blood-brain barrier (BBB) leakage, and cognitive impairments. These changes were associated with diminished vascular smooth muscle cell contractile capability linked to elevated reactive oxygen species (ROS) and reduced ATP production. In the present study, using a nonobese T2DN DM rat, we isolated parenchymal arterioles (PAs), cultured cerebral microvascular pericytes, and examined whether cerebrovascular pericyte in DM is damaged and whether pericyte dysfunction may play a role in the regulation of cerebral hemodynamics and BBB integrity. We found that ROS and mitochondrial superoxide production were elevated in PAs isolated from old DM rats and in high glucose (HG)-treated α-smooth muscle actin-positive pericytes. HG-treated pericytes displayed decreased contractile capability in association with diminished mitochondrial respiration and ATP production. Additionally, the expression of advanced glycation end products, transforming growth factor-β, vascular endothelial growth factor, and fibronectin were enhanced, but claudin 5 and integrin β1 was reduced in the brain of old DM rats and HG-treated pericytes. Further, endothelial tight junction and pericyte coverage on microvessels were reduced in the cortex of old DM rats. These results demonstrate our previous findings that the impaired cerebral hemodynamics and BBB leakage and cognitive impairments in the same old DM model are associated with hyperglycemia-induced cerebrovascular pericyte dysfunction.NEW & NOTEWORTHY This study demonstrates that the loss of contractile capability in pericytes in diabetes is associated with enhanced ROS and reduced ATP production. Enhanced advanced glycation end products (AGEs) in diabetes accompany with reduced pericyte and endothelial tight junction coverage in the cortical capillaries of old diabetic rats. These results suggest our previous findings that the impaired cerebral hemodynamics, BBB leakage, and cognitive impairments in old DM model are associated with hyperglycemia-induced cerebrovascular pericyte dysfunction.
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Affiliation(s)
- Yedan Liu
- Department of Pediatrics, Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Huawei Zhang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Shaoxun Wang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Ya Guo
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Xing Fang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Baoying Zheng
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Wenjun Gao
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Hongwei Yu
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Zongbo Chen
- Department of Pediatrics, Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Richard J Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
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Fontaine JT, Rosehart AC, Joutel A, Dabertrand F. HB-EGF depolarizes hippocampal arterioles to restore myogenic tone in a genetic model of small vessel disease. Mech Ageing Dev 2020; 192:111389. [PMID: 33127441 PMCID: PMC7683376 DOI: 10.1016/j.mad.2020.111389] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 10/16/2020] [Accepted: 10/22/2020] [Indexed: 12/26/2022]
Abstract
Vascular cognitive impairment, the second most common cause of dementia, profoundly affects hippocampal-dependent functions. However, while the growing literature covers complex neuronal interactions, little is known about the sustaining hippocampal microcirculation. Here we examined vasoconstriction to physiological pressures of hippocampal arterioles, a fundamental feature of small arteries, in a genetic mouse model of CADASIL, an archetypal cerebral small vessel disease. Using diameter and membrane potential recordings on isolated arterioles, we observed both blunted pressure-induced vasoconstriction and smooth muscle cell depolarization in CADASIL. This impairment was abolished in the presence of voltage-gated potassium (KV1) channel blocker 4-aminopyridine, or by application of heparin-binding EGF-like growth factor (HB-EGF), which promotes KV1 channel down-regulations. Interestingly, we observed that HB-EGF induced a depolarization of the myocyte plasma membrane within the arteriolar wall in CADASIL, but not wild-type, arterioles. Collectively, our results indicate that hippocampal arterioles in CADASIL mice display a blunted contractile response to luminal pressure, similar to the defect we previously reported in cortical arterioles and pial arteries, that is rescued by HB-EGF. Hippocampal vascular dysfunction in CADASIL could then contribute to the decreased vascular reserve associated with decreased cognitive performance, and its correction may provide a therapeutic option for treating vascular cognitive impairment.
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Affiliation(s)
- Jackson T Fontaine
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Amanda C Rosehart
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Anne Joutel
- Department of Pharmacology, Larner College of Medicine University of Vermont, Burlington, VT, USA; Institute of Psychiatry and Neurosciences of Paris, INSERM UMR1266, University of Paris, GHU Paris Psychiatrie et Neurosciences, France
| | - Fabrice Dabertrand
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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11
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Li L, Lai EY, Cao X, Welch WJ, Wilcox CS. Endothelial prostaglandin D 2 opposes angiotensin II contractions in mouse isolated perfused intracerebral microarterioles. J Renin Angiotensin Aldosterone Syst 2020; 21:1470320320966177. [PMID: 33094663 PMCID: PMC7585895 DOI: 10.1177/1470320320966177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Hypothesis: A lack of contraction of cerebral microarterioles to Ang II (“resilience”) depends on cyclooxygenase (COX) and lipocalin type prostaglandin D sythase L-PGDS producing PGD2 that activates prostaglandin D type 1 receptors (DP1Rs) and nitric oxide synthase (NOS). Materials & Methods: Contractions were assessed in isolated, perfused vessels and NO by fluorescence microscopy. Results: The mRNAs of penetrating intraparenchymal cerebral microarterioles versus renal afferent arterioles were >3000-fold greater for L-PGDS and DP1R and 5-fold for NOS III and COX 2. Larger cerebral arteries contracted with Ang II. However, cerebral microarterioles were entirely unresponsive but contracted with endothelin 1 and perfusion pressure. Ang II contractions were evoked in cerebral microarterioles from COX1 –/– mice or after blockade of COX2, L-PGDS or NOS and in deendothelialized vessels but effects of deendothelialization were lost during COX blockade. NO generation with Ang II depended on COX and also was increased by DP1R activation. Conclusion: The resilience of cerebral arterioles to Ang II contractions is specific for intraparenchymal microarterioles and depends on endothelial COX1 and two products that are metabolized by L-PGDS to generate PGD2 that signals via DP1Rs and NO.
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Affiliation(s)
- L Li
- Hypertension Center and Division of Nephrology and Hypertension, Georgetown University, Washington DC, USA.,Kidney Disease Center, the First Affiliated Hospital and Department of Physiology, School of Basic Medical Science, Zhejiang University School of Medicine, Hangzhou, China
| | - E Y Lai
- Hypertension Center and Division of Nephrology and Hypertension, Georgetown University, Washington DC, USA.,Kidney Disease Center, the First Affiliated Hospital and Department of Physiology, School of Basic Medical Science, Zhejiang University School of Medicine, Hangzhou, China
| | - X Cao
- Kidney Disease Center, the First Affiliated Hospital and Department of Physiology, School of Basic Medical Science, Zhejiang University School of Medicine, Hangzhou, China
| | - W J Welch
- Hypertension Center and Division of Nephrology and Hypertension, Georgetown University, Washington DC, USA
| | - C S Wilcox
- Hypertension Center and Division of Nephrology and Hypertension, Georgetown University, Washington DC, USA
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12
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Wang S, Lv W, Zhang H, Liu Y, Li L, Jefferson JR, Guo Y, Li M, Gao W, Fang X, Paul IA, Rajkowska G, Shaffery JP, Mosley TH, Hu X, Liu R, Wang Y, Yu H, Roman RJ, Fan F. Aging exacerbates impairments of cerebral blood flow autoregulation and cognition in diabetic rats. GeroScience 2020; 42:1387-1410. [PMID: 32696219 DOI: 10.1007/s11357-020-00233-w] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 07/08/2020] [Indexed: 02/06/2023] Open
Abstract
Diabetes mellitus (DM) is a leading risk factor for aging-related dementia; however, the underlying mechanisms are not well understood. The present study, utilizing a non-obese T2DN diabetic model, demonstrates that the myogenic response of the middle cerebral artery (MCA) and parenchymal arteriole (PA) and autoregulation of cerebral blood flow (CBF) in the surface and deep cortex were impaired at both young and old ages. The impaired CBF autoregulation was more severe in old than young DM rats, and in the deep than the surface cortex. The myogenic tone of the MCA was enhanced at perfusion pressure in the range of 40-100 mmHg in young DM rats but was reduced at 140-180 mmHg in old DM rats. No change of the myogenic tone of the PA was observed in young DM rats, whereas it was significantly reduced at 30-60 mmHg in old DM rats. Old DM rats had enhanced blood-brain barrier (BBB) leakage and neurodegeneration, reduced vascular density, tight junction, and pericyte coverage on cerebral capillaries in the CA3 region in the hippocampus. Additionally, DM rats displayed impaired functional hyperemia and spatial learning and short- and long-term memory at both young and old ages. Old DM rats had impaired non-spatial short-term memory. These results revealed that impaired CBF autoregulation and enhanced BBB leakage plays an essential role in the pathogenesis of age- and diabetes-related dementia. These findings will lay the foundations for the discovery of anti-diabetic therapies targeting restoring CBF autoregulation to prevent the onset and progression of dementia in elderly DM.
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Affiliation(s)
- Shaoxun Wang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Wenshan Lv
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA.,Department of Endocrinology and Metabolic, The Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong, China
| | - Huawei Zhang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Yedan Liu
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Longyang Li
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Joshua R Jefferson
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Ya Guo
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Man Li
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Wenjun Gao
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Xing Fang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Ian A Paul
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Grazyna Rajkowska
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - James P Shaffery
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Thomas H Mosley
- Department of Neurology, University of Mississippi Medical Center, Jackson, MS, 39216, USA.,Department of Medicine (Geriatrics), University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Xinlin Hu
- Department of Endocrinology and Metabolic, The Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong, China
| | - Ruen Liu
- Department of Neurosurgery, Peking University People's Hospital, Beijing, 100044, China
| | - Yangang Wang
- Department of Endocrinology and Metabolic, The Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong, China
| | - Hongwei Yu
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Richard J Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA.
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13
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Yamasaki E, Thakore P, Krishnan V, Earley S. Differential expression of angiotensin II type 1 receptor subtypes within the cerebral microvasculature. Am J Physiol Heart Circ Physiol 2020; 318:H461-H469. [PMID: 31886721 PMCID: PMC7052625 DOI: 10.1152/ajpheart.00582.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 12/10/2019] [Accepted: 12/24/2019] [Indexed: 01/12/2023]
Abstract
Arteries and arterioles constrict in response to intraluminal pressure to generate myogenic tone, but the molecular nature of the vascular force-sensing mechanism is not fully characterized. Here, we investigated the role of angiotensin II type 1 receptors (AT1Rs) on vascular smooth muscle cells in the development of myogenic tone in cerebral parenchymal arterioles from mice. We found that pretreatment with the AT1R blocker losartan inhibited the development of myogenic tone in these vessels but did not alter the luminal diameter of arterioles with preestablished tone. Rodents express two AT1R isotypes: AT1Ra and AT1Rb. We previously demonstrated that AT1Rb is expressed at much higher levels compared with AT1Ra in cerebral pial arteries and is required for myogenic contractility in these vessels, whereas AT1Ra is unnecessary for this function. Here, we found that AT1Ra and AT1Rb are expressed at similar levels in parenchymal arterioles and that genetic knockout of AT1Ra blunted the ability of these vessels to generate myogenic tone. We also found that AT1Rb and total AT1R expression levels are much lower in parenchymal arterioles compared with pial arteries and that parenchymal arterioles are less sensitive to the vasoconstrictive effects of the endogenous AT1R ligand angiotensin II (ANG II). We conclude that 1) AT1Rs are critical for the initiation, but not the maintenance, of myogenic tone in parenchymal arterioles, and 2) lower levels of AT1Rb and total AT1R in parenchymal arterioles compared with pial arteries result in differences in myogenic and ANG II-induced vasoconstriction between these vascular segments.NEW & NOTEWORTHY Myogenic tone is critical for appropriate regulation of cerebral blood flow, but the mechanisms used by vascular smooth muscle cells to detect changes in intraluminal pressure are not fully characterized. Here, we demonstrate angiotensin II receptor type 1 (AT1R) is indispensable to initiation, but not maintenance, of myogenic tone in cerebral parenchymal arterioles. Furthermore, we demonstrate differences in AT1R expression levels lead to critical differences in contractile regulation between parenchymal arterioles and cerebral pial arteries.
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Affiliation(s)
- Evan Yamasaki
- Department of Pharmacology, Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, Nevada
| | - Pratish Thakore
- Department of Pharmacology, Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, Nevada
| | - Vivek Krishnan
- Department of Pharmacology, Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, Nevada
| | - Scott Earley
- Department of Pharmacology, Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, Nevada
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14
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Zhang H, Zhang C, Liu Y, Gao W, Wang S, Fang X, Guo Y, Li M, Liu R, Roman RJ, Sun P, Fan F. Influence of dual-specificity protein phosphatase 5 on mechanical properties of rat cerebral and renal arterioles. Physiol Rep 2020; 8:e14345. [PMID: 31960618 PMCID: PMC6971329 DOI: 10.14814/phy2.14345] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 12/14/2019] [Accepted: 12/18/2019] [Indexed: 12/18/2022] Open
Abstract
We recently reported that KO of Dual-specificity protein phosphatase 5 (Dusp5) enhances myogenic reactivity and blood flow autoregulation in the cerebral and renal circulations in association with increased levels of pPKC and pERK1/2 in the cerebral and renal arteries and arterioles. In the kidney, hypertension-related renal damage was significantly attenuated in Dusp5 KO rats. Elevations in pPKC and pERK1/2 promote calcium influx in VSMC and facilitate vasoconstriction. However, whether DUSP5 plays a role in altering the passive mechanical properties of cerebral and renal arterioles has never been investigated. In this study, we found that KO of Dusp5 did not alter body weights, kidney and brain weights, plasma glucose, and HbA1C levels. The expression of pERK is higher in the nucleus of primary VSMC isolated from Dusp5 KO rats. Dusp5 KO rats exhibited eutrophic vascular hypotrophy with smaller intracerebral parenchymal arterioles and renal interlobular arterioles without changing the wall-to-lumen ratios. These arterioles from Dusp5 KO rats displayed higher myogenic tones, better distensibility, greater compliance, and less stiffness compared with arterioles from WT control rats. VSMC of Dusp5 KO rats exhibited a stronger contractile capability. These results demonstrate, for the first time, that DUSP5 contributes to the regulation of the passive mechanical properties of cerebral and renal arterioles and provide new insights into the role of DUSP5 in vascular function, cancer, stroke, and other cardiovascular diseases.
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Affiliation(s)
- Huawei Zhang
- Department of Pharmacology and ToxicologyUniversity of Mississippi Medical CenterJacksonMSUSA
- Department of NeurosurgeryAffiliated Hospital of Qingdao UniversityQingdaoChina
| | - Chao Zhang
- Department of Pharmacology and ToxicologyUniversity of Mississippi Medical CenterJacksonMSUSA
| | - Yedan Liu
- Department of Pharmacology and ToxicologyUniversity of Mississippi Medical CenterJacksonMSUSA
| | - Wenjun Gao
- Department of Pharmacology and ToxicologyUniversity of Mississippi Medical CenterJacksonMSUSA
| | - Shaoxun Wang
- Department of Pharmacology and ToxicologyUniversity of Mississippi Medical CenterJacksonMSUSA
| | - Xing Fang
- Department of Pharmacology and ToxicologyUniversity of Mississippi Medical CenterJacksonMSUSA
| | - Ya Guo
- Department of Pharmacology and ToxicologyUniversity of Mississippi Medical CenterJacksonMSUSA
| | - Man Li
- Department of Pharmacology and ToxicologyUniversity of Mississippi Medical CenterJacksonMSUSA
| | - Ruen Liu
- Department of NeurosurgeryPeking University People's HospitalBeijingChina
| | - Richard J. Roman
- Department of Pharmacology and ToxicologyUniversity of Mississippi Medical CenterJacksonMSUSA
| | - Peng Sun
- Department of NeurosurgeryAffiliated Hospital of Qingdao UniversityQingdaoChina
| | - Fan Fan
- Department of Pharmacology and ToxicologyUniversity of Mississippi Medical CenterJacksonMSUSA
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15
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Rosehart AC, Johnson AC, Dabertrand F. Ex Vivo Pressurized Hippocampal Capillary-Parenchymal Arteriole Preparation for Functional Study. J Vis Exp 2019. [PMID: 31904015 DOI: 10.3791/60676] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
From subtle behavioral alterations to late-stage dementia, vascular cognitive impairment typically develops following cerebral ischemia. Stroke and cardiac arrest are remarkably sexually dimorphic diseases, and both induce cerebral ischemia. However, progress in understanding the vascular cognitive impairment, and then developing sex-specific treatments, has been partly limited by challenges in investigating the brain microcirculation from mouse models in functional studies. Here, we present an approach to examine the capillary-to-arteriole signaling in an ex vivo hippocampal capillary-parenchymal arteriole (HiCaPA) preparation from mouse brain. We describe how to isolate, cannulate, and pressurize the microcirculation to measure arteriolar diameter in response to capillary stimulation. We show which appropriate functional controls can be used to validate the HiCaPA preparation integrity and display typical results, including testing potassium as a neurovascular coupling agent and the effect of the recently characterized inhibitor of the Kir2 inward rectifying potassium channel family, ML133. Further, we compare the responses in preparations obtained from male and female mice. While these data reflect functional investigations, our approach can also be used in molecular biology, immunochemistry, and electrophysiology studies.
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Affiliation(s)
- Amanda C Rosehart
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus
| | - Abbie C Johnson
- Department of Neurological Sciences, University of Vermont Larner College of Medicine
| | - Fabrice Dabertrand
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus; Department of Pharmacology, University of Colorado Anschutz Medical Campus;
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16
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Behringer EJ, Hakim MA. Functional Interaction among K Ca and TRP Channels for Cardiovascular Physiology: Modern Perspectives on Aging and Chronic Disease. Int J Mol Sci 2019; 20:ijms20061380. [PMID: 30893836 PMCID: PMC6471369 DOI: 10.3390/ijms20061380] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 03/07/2019] [Accepted: 03/15/2019] [Indexed: 12/16/2022] Open
Abstract
Effective delivery of oxygen and essential nutrients to vital organs and tissues throughout the body requires adequate blood flow supplied through resistance vessels. The intimate relationship between intracellular calcium ([Ca2+]i) and regulation of membrane potential (Vm) is indispensable for maintaining blood flow regulation. In particular, Ca2+-activated K+ (KCa) channels were ascertained as transducers of elevated [Ca2+]i signals into hyperpolarization of Vm as a pathway for decreasing vascular resistance, thereby enhancing blood flow. Recent evidence also supports the reverse role for KCa channels, in which they facilitate Ca2+ influx into the cell interior through open non-selective cation (e.g., transient receptor potential; TRP) channels in accord with robust electrical (hyperpolarization) and concentration (~20,000-fold) transmembrane gradients for Ca2+. Such an arrangement supports a feed-forward activation of Vm hyperpolarization while potentially boosting production of nitric oxide. Furthermore, in vascular types expressing TRP channels but deficient in functional KCa channels (e.g., collecting lymphatic endothelium), there are profound alterations such as downstream depolarizing ionic fluxes and the absence of dynamic hyperpolarizing events. Altogether, this review is a refined set of evidence-based perspectives focused on the role of the endothelial KCa and TRP channels throughout multiple experimental animal models and vascular types. We discuss the diverse interactions among KCa and TRP channels to integrate Ca2+, oxidative, and electrical signaling in the context of cardiovascular physiology and pathology. Building from a foundation of cellular biophysical data throughout a wide and diverse compilation of significant discoveries, a translational narrative is provided for readers toward the treatment and prevention of chronic, age-related cardiovascular disease.
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Affiliation(s)
- Erik J Behringer
- Department of Basic Sciences, 11041 Campus Street, Risley Hall, Loma Linda University, Loma Linda, CA 92350, USA.
| | - Md A Hakim
- Department of Basic Sciences, 11041 Campus Street, Risley Hall, Loma Linda University, Loma Linda, CA 92350, USA.
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17
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Pires PW, Earley S. Neuroprotective effects of TRPA1 channels in the cerebral endothelium following ischemic stroke. eLife 2018; 7:35316. [PMID: 30239332 PMCID: PMC6177258 DOI: 10.7554/elife.35316] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 09/18/2018] [Indexed: 02/07/2023] Open
Abstract
Hypoxia and ischemia are linked to oxidative stress, which can activate the oxidant-sensitive transient receptor potential ankyrin 1 (TRPA1) channel in cerebral artery endothelial cells, leading to vasodilation. We hypothesized that TRPA1 channels in endothelial cells are activated by hypoxia-derived reactive oxygen species, leading to cerebral artery dilation and reduced ischemic damage. Using isolated cerebral arteries expressing a Ca2+ biosensor in endothelial cells, we show that 4-hydroxynonenal and hypoxia increased TRPA1 activity, detected as TRPA1 sparklets. TRPA1 activity during hypoxia was blocked by antioxidants and by TRPA1 antagonism. Hypoxia caused dilation of cerebral arteries, which was disrupted by antioxidants, TRPA1 blockade and by endothelial cell-specific Trpa1 deletion (Trpa1 ecKO mice). Loss of TRPA1 channels in endothelial cells increased cerebral infarcts, whereas TRPA1 activation with cinnamaldehyde reduced infarct in wildtype, but not Trpa1 ecKO, mice. These data suggest that endothelial TRPA1 channels are sensors of hypoxia leading to vasodilation, thereby reducing ischemic damage.
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Affiliation(s)
- Paulo Wagner Pires
- Department of Pharmacology, Center for Cardiovascular Research, University of Nevada, Reno, United States
| | - Scott Earley
- Department of Pharmacology, Center for Cardiovascular Research, University of Nevada, Reno, United States
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18
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Nanoscale remodeling of ryanodine receptor cluster size underlies cerebral microvascular dysfunction in Duchenne muscular dystrophy. Proc Natl Acad Sci U S A 2018; 115:E9745-E9752. [PMID: 30181262 PMCID: PMC6187127 DOI: 10.1073/pnas.1804593115] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a hereditary neuromuscular disease that results from mutations in the gene encoding dystrophin. The effects of the disease on cardiac and skeletal muscle have been intensely investigated, but much less is known about how DMD impacts vascular smooth muscle cells (SMCs). Using superresolution nanoscopy, we demonstrate that clusters of ryanodine receptors (RyR2s) on the sarcoplasmic reticulum (SR) of cerebral artery SMCs from the mdx mouse model of DMD are larger compared with controls. Increased RyR2 cluster size is associated with augmented SR Ca2+ release and Ca2+-activated K+ channel activity, resulting in impaired vasoconstriction of cerebral microvessels. Our findings demonstrate that remodeling of RyR2 clusters at the molecular level results in cerebral microvascular dysfunction during DMD. Duchenne muscular dystrophy (DMD) results from mutations in the gene encoding dystrophin which lead to impaired function of skeletal and cardiac muscle, but little is known about the effects of the disease on vascular smooth muscle cells (SMCs). Here we used the mdx mouse model to study the effects of mutant dystrophin on the regulation of cerebral artery and arteriole SMC contractility, focusing on an important Ca2+-signaling pathway composed of type 2 ryanodine receptors (RyR2s) on the sarcoplasmic reticulum (SR) and large-conductance Ca2+-activated K+ (BK) channels on the plasma membrane. Nanoscale superresolution image analysis revealed that RyR2 and BKα were organized into discrete clusters, and that the mean size of RyR2 clusters that colocalized with BKα was larger in SMCs from mdx mice (∼62 RyR2 monomers) than in controls (∼40 RyR2 monomers). We further found that the frequency and signal mass of spontaneous, transient Ca2+-release events through SR RyR2s (“Ca2+ sparks”) were greater in SMCs from mdx mice. Patch-clamp electrophysiological recordings indicated a corresponding increase in Ca2+-dependent BK channel activity. Using pressure myography, we found that cerebral pial arteries and parenchymal arterioles from mdx mice failed to develop appreciable spontaneous myogenic tone. Inhibition of RyRs with tetracaine and blocking of BK channels with paxilline restored myogenic tone to control levels, demonstrating that enhanced RyR and BK channel activity is responsible for the diminished pressure-induced constriction of arteries and arterioles from mdx mice. We conclude that increased size of RyR2 protein clusters in SMCs from mdx mice increases Ca2+ spark and BK channel activity, resulting in cerebral microvascular dysfunction.
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