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Jeong H, Lee D, Negishi K, Tsubota K, Kurihara T. Establishment of an in vitro choroid complex system for vascular response screening. Sci Rep 2024; 14:16129. [PMID: 38997397 PMCID: PMC11245503 DOI: 10.1038/s41598-024-67069-8] [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: 02/28/2024] [Accepted: 07/08/2024] [Indexed: 07/14/2024] Open
Abstract
The choroid, a vascularized tissue situated between the retina and the sclera, plays a crucial role in maintaining ocular homeostasis. Despite its significance, research on choroidal abnormalities and the establishment of effective in vitro models have been limited. In this study, we developed an in vitro choroid model through the co-culture of human induced pluripotent stem cells (hiPSC)-derived endothelial cells (ECs) and mouse choroidal fibroblasts (msCFs) with hiPSC-derived retinal pigment epithelial (RPE) cells via a permeable membrane. This model, inclusive of ECs, CFs, and RPE cells, exhibited similarities with in vivo choroidal vessels, as confirmed through immunohistochemistry of extracellular matrix markers and vascular-related markers, as well as choroid angiogenesis sprouting assay analysis. The effectiveness of our in vitro model was demonstrated in assessing vascular changes induced by drugs targeting vasoregulation. Our model offers a valuable tool for gaining insights into the pathological mechanisms underlying choroid development and the progression of choroidal vascular diseases.
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Affiliation(s)
- Heonuk Jeong
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-Ku, Tokyo, 160-8582, Japan
- Laboratory of Photobiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-Ku, Tokyo, 160-8582, Japan
| | - Deokho Lee
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-Ku, Tokyo, 160-8582, Japan
- Laboratory of Photobiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-Ku, Tokyo, 160-8582, Japan
| | - Kazuno Negishi
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-Ku, Tokyo, 160-8582, Japan
| | - Kazuo Tsubota
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-Ku, Tokyo, 160-8582, Japan.
- Tsubota Laboratory, Inc, 304 Toshin Shinanomachi-Ekimae Bldg., 34 Shinanomachi, Shinjuku-Ku, Tokyo, 160-0016, Japan.
| | - Toshihide Kurihara
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-Ku, Tokyo, 160-8582, Japan.
- Laboratory of Photobiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-Ku, Tokyo, 160-8582, Japan.
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2
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Wellman S, Forrest AM, Douglas MM, Subbaraman A, Zhang G, Kozai TDY. Dynamic changes in structure and function of brain mural cells around chronically implanted microelectrodes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.11.598494. [PMID: 38915601 PMCID: PMC11195141 DOI: 10.1101/2024.06.11.598494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Integration of neural interfaces with minimal tissue disruption in the brain is ideal to develop robust tools that can address essential neuroscience questions and combat neurological disorders. However, implantation of intracortical devices provokes severe tissue inflammation within the brain, which requires a high metabolic demand to support a complex series of cellular events mediating tissue degeneration and wound healing. Pericytes, peri-vascular cells involved in blood-brain barrier maintenance, vascular permeability, waste clearance, and angiogenesis, have recently been implicated as potential perpetuators of neurodegeneration in brain injury and disease. While the intimate relationship between pericytes and the cortical microvasculature have been explored in other disease states, their behavior following microelectrode implantation, which is responsible for direct blood vessel disruption and dysfunction, is currently unknown. Using two-photon microscopy we observed dynamic changes in the structure and function of pericytes during implantation of a microelectrode array over a 4-week implantation period. Pericytes respond to electrode insertion through transient increases in intracellular calcium and underlying constriction of capillary vessels. Within days following the initial insertion, we observed an influx of new, proliferating pericytes which contribute to new blood vessel formation. Additionally, we discovered a potentially novel population of reactive immune cells in close proximity to the electrode-tissue interface actively engaging in encapsulation of the microelectrode array. Finally, we determined that intracellular pericyte calcium can be modulated by intracortical microstimulation in an amplitude- and frequency-dependent manner. This study provides a new perspective on the complex biological sequelae occurring the electrode-tissue interface and will foster new avenues of potential research consideration and lead to development of more advanced therapeutic interventions towards improving the biocompatibility of neural electrode technology.
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3
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Montalant A, Kiehn O, Perrier JF. Dopamine and noradrenaline activate spinal astrocyte endfeet via D1-like receptors. Eur J Neurosci 2024; 59:1278-1295. [PMID: 38052454 DOI: 10.1111/ejn.16205] [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: 09/08/2023] [Revised: 11/02/2023] [Accepted: 11/10/2023] [Indexed: 12/07/2023]
Abstract
Astrocytes, the most abundant glial cells in the central nervous system, respond to a wide variety of neurotransmitters binding to metabotropic receptors. Here, we investigated the intracellular calcium responses of spinal cord astrocytes to dopamine and noradrenaline, two catecholamines released by specific descending pathways. In a slice preparation from the spinal cord of neonatal mice, puff application of dopamine resulted in intracellular calcium responses that remained in the endfeet. Noradrenaline induced stronger responses that also started in the endfeet but spread to neighbouring compartments. The intracellular calcium responses were unaffected by blocking neuronal activity or inhibiting various neurotransmitter receptors, suggesting a direct effect of dopamine and noradrenaline on astrocytes. The intracellular calcium responses induced by noradrenaline and dopamine were inhibited by the D1 receptor antagonist SCH 23390. We assessed the functional consequences of these astrocytic responses by examining changes in arteriole diameter. Puff application of dopamine or noradrenaline resulted in vasoconstriction of spinal arterioles. However, blocking D1 receptors or manipulating astrocytic intracellular calcium levels did not abolish the vasoconstrictions, indicating that the observed intracellular calcium responses in astrocyte endfeet were not responsible for the vascular changes. Our findings demonstrate a compartmentalized response of spinal cord astrocytes to catecholamines and expand our understanding of astrocyte-neurotransmitter interactions and their potential roles in the physiology of the central nervous system.
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Affiliation(s)
- Alexia Montalant
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ole Kiehn
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jean-François Perrier
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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4
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Cerri DH, Albaugh DL, Walton LR, Katz B, Wang TW, Chao THH, Zhang W, Nonneman RJ, Jiang J, Lee SH, Etkin A, Hall CN, Stuber GD, Shih YYI. Distinct neurochemical influences on fMRI response polarity in the striatum. Nat Commun 2024; 15:1916. [PMID: 38429266 PMCID: PMC10907631 DOI: 10.1038/s41467-024-46088-z] [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: 03/30/2023] [Accepted: 02/13/2024] [Indexed: 03/03/2024] Open
Abstract
The striatum, known as the input nucleus of the basal ganglia, is extensively studied for its diverse behavioral roles. However, the relationship between its neuronal and vascular activity, vital for interpreting functional magnetic resonance imaging (fMRI) signals, has not received comprehensive examination within the striatum. Here, we demonstrate that optogenetic stimulation of dorsal striatal neurons or their afferents from various cortical and subcortical regions induces negative striatal fMRI responses in rats, manifesting as vasoconstriction. These responses occur even with heightened striatal neuronal activity, confirmed by electrophysiology and fiber-photometry. In parallel, midbrain dopaminergic neuron optogenetic modulation, coupled with electrochemical measurements, establishes a link between striatal vasodilation and dopamine release. Intriguingly, in vivo intra-striatal pharmacological manipulations during optogenetic stimulation highlight a critical role of opioidergic signaling in generating striatal vasoconstriction. This observation is substantiated by detecting striatal vasoconstriction in brain slices after synthetic opioid application. In humans, manipulations aimed at increasing striatal neuronal activity likewise elicit negative striatal fMRI responses. Our results emphasize the necessity of considering vasoactive neurotransmission alongside neuronal activity when interpreting fMRI signal.
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Affiliation(s)
- Domenic H Cerri
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Daniel L Albaugh
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Lindsay R Walton
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Brittany Katz
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Tzu-Wen Wang
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Tzu-Hao Harry Chao
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Weiting Zhang
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Randal J Nonneman
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jing Jiang
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA
- Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, IA, USA
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Sung-Ho Lee
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Amit Etkin
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA
- Alto Neuroscience, Los Altos, CA, USA
| | - Catherine N Hall
- Sussex Neuroscience, University of Sussex, Falmer, United Kingdom
- School of Psychology, University of Sussex, Falmer, United Kingdom
| | - Garret D Stuber
- Center for Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, WA, USA
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA
- Department of Pharmacology, University of Washington, Seattle, WA, USA
| | - Yen-Yu Ian Shih
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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5
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Guan Y, Gu Y, Shao H, Ma W, Li G, Guo M, Shao Q, Li Y, Liu Y, Wang C, Tian Z, Liu J, Ji X. Intermittent hypoxia protects against hypoxic-ischemic brain damage by inducing functional angiogenesis. J Cereb Blood Flow Metab 2023; 43:1656-1671. [PMID: 37395346 PMCID: PMC10581229 DOI: 10.1177/0271678x231185507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 06/12/2023] [Accepted: 06/13/2023] [Indexed: 07/04/2023]
Abstract
Ischemic stroke (IS) induces neurological damage due to cerebrovascular occlusion. Restoring blood perfusion to the ischemic brain area in a timely fashion is the most effective treatment strategy. Hypoxia is an effective way of restoring blood perfusion by improving cerebrovascular microcirculation, while the effect varies greatly depending on hypoxic mode. This study aimed to screen for the optimal hypoxic mode to improve cerebrovascular microcirculation and prevent IS. Here, we found that compared with continuous hypoxia (CH), intermittent hypoxia (IH) significantly improved cerebral blood flow and oxygen saturation in mice without causing neurological impairment. By analyzing cerebrovascular microcirculation from mice, we found that the IH mode (13%, 5*10) with 13% O2, 5 min interval, and 10 cycles per day significantly improved the cerebrovascular microcirculation by promoting angiogenesis without affecting the integrity of the blood-brain barrier. In addition, IH (13%, 5*10) treatment of distal middle cerebral artery occlusion (dMCAO) mice significantly alleviated neurological dysfunction and reduced cerebral infarct volume by improving cerebrovascular microcirculation. CH had none of these positive effects. In summary, our study screened for an appropriate intermittent hypoxic mode that could improve cerebrovascular microcirculation, laying a theoretical foundation for the prevention and treatment of IS in clinical practice.
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Affiliation(s)
- Yuying Guan
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yakun Gu
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
| | - Haitao Shao
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
| | - Wei Ma
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
| | - Gaifen Li
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Mengyuan Guo
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
| | - Qianqian Shao
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
| | - Yuning Li
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
| | - Yingxia Liu
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
| | - Chaoyu Wang
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
| | - Zhengming Tian
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
| | - Jia Liu
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
| | - Xunming Ji
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
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6
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Hirunpattarasilp C, James G, Kwanthongdee J, Freitas F, Huo J, Sethi H, Kittler JT, Owens RJ, McCoy LE, Attwell D. SARS-CoV-2 triggers pericyte-mediated cerebral capillary constriction. Brain 2023; 146:727-738. [PMID: 35867861 PMCID: PMC9384509 DOI: 10.1093/brain/awac272] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 07/04/2022] [Accepted: 07/11/2022] [Indexed: 11/21/2022] Open
Abstract
The SARS-CoV-2 receptor, ACE2, is found on pericytes, contractile cells enwrapping capillaries that regulate brain, heart and kidney blood flow. ACE2 converts vasoconstricting angiotensin II into vasodilating angiotensin-(1-7). In brain slices from hamster, which has an ACE2 sequence similar to human ACE2, angiotensin II evoked a small pericyte-mediated capillary constriction via AT1 receptors, but evoked a large constriction when the SARS-CoV-2 receptor binding domain (RBD, original Wuhan variant) was present. A mutated non-binding RBD did not potentiate constriction. A similar RBD-potentiated capillary constriction occurred in human cortical slices, and was evoked in hamster brain slices by pseudotyped virions expressing SARS-CoV-2 spike protein. This constriction reflects an RBD-induced decrease in the conversion of angiotensin II to angiotensin-(1-7) mediated by removal of ACE2 from the cell surface membrane and was mimicked by blocking ACE2. The clinically used drug losartan inhibited the RBD-potentiated constriction. Thus, AT1 receptor blockers could be protective in COVID-19 by preventing pericyte-mediated blood flow reductions in the brain, and perhaps the heart and kidney.
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Affiliation(s)
- Chanawee Hirunpattarasilp
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
- Princess Srisavangavadhana College of Medicine, Chulabhorn Royal Academy, Talat Bang Khen, Lak Si, Bangkok, 10210, Thailand
| | - Greg James
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
- Department of Neurosurgery, Great Ormond Street Hospital, London WC1N 3JH, UK
| | - Jaturon Kwanthongdee
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
- Princess Srisavangavadhana College of Medicine, Chulabhorn Royal Academy, Talat Bang Khen, Lak Si, Bangkok, 10210, Thailand
| | - Felipe Freitas
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Jiandong Huo
- Division of Structural Biology, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7BN, UK
- Protein Production UK, The Research Complex at Harwell, and Rosalind Franklin Institute, Harwell Science and Innovation Campus, Didcot OX11 0GD, UK
| | - Huma Sethi
- Division of Neurosurgery, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Josef T Kittler
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Raymond J Owens
- Division of Structural Biology, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7BN, UK
- Protein Production UK, The Research Complex at Harwell, and Rosalind Franklin Institute, Harwell Science and Innovation Campus, Didcot OX11 0GD, UK
| | - Laura E McCoy
- Division of Infection and Immunity, University College London, London NW3 2PP, UK
| | - David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
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7
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Bojovic D, Stackhouse TL, Mishra A. Assaying activity-dependent arteriole and capillary responses in brain slices. NEUROPHOTONICS 2022; 9:031913. [PMID: 35558646 PMCID: PMC9089234 DOI: 10.1117/1.nph.9.3.031913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 03/31/2022] [Indexed: 06/15/2023]
Abstract
Significance: Neurovascular coupling (NVC) is the process that increases cerebral blood flow in response to neuronal activity. NVC is orchestrated by signaling between neurons, glia, and vascular cells. Elucidating the mechanisms underlying NVC at different vascular segments and in different brain regions is imperative for understanding of brain function and mechanisms of dysfunction. Aim: Our goal is to describe a protocol for concurrently monitoring stimulation-evoked neuronal activity and resultant vascular responses in acute brain slices. Approach: We describe a step-by-step protocol that allows the study of endogenous NVC mechanisms engaged by neuronal activity in a controlled, reduced preparation. Results: This ex vivo NVC assay allows researchers to disentangle the mechanisms regulating the contractile responses of different vascular segments in response to neuronal firing independent of flow and pressure mediated effects from connected vessels. It also enables easy pharmacological manipulations in a simplified, reduced system and can be combined with Ca 2 + imaging or broader electrophysiology techniques to obtain multimodal data during NVC. Conclusions: The ex vivo NVC assay will facilitate investigations of cellular and molecular mechanisms that give rise to NVC and should serve as a valuable complement to in vivo imaging methods.
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Affiliation(s)
- Danica Bojovic
- Oregon Health & Science University, Jungers Center for Neurosciences Research, Department of Neurology, Portland, Oregon, United States
- Oregon Health & Science University, Vollum Institute, Portland, Oregon, United States
| | - Teresa L. Stackhouse
- Oregon Health & Science University, Jungers Center for Neurosciences Research, Department of Neurology, Portland, Oregon, United States
| | - Anusha Mishra
- Oregon Health & Science University, Jungers Center for Neurosciences Research, Department of Neurology, Portland, Oregon, United States
- Oregon Health & Science University, Knight Cardiovascular Institute, Portland, Oregon, United States
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8
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Jeffrey DA, Fontaine JT, Dabertrand F. Ex vivo capillary-parenchymal arteriole approach to study brain pericyte physiology. NEUROPHOTONICS 2022; 9:031919. [PMID: 36278784 PMCID: PMC9225307 DOI: 10.1117/1.nph.9.3.031919] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 06/01/2022] [Indexed: 06/16/2023]
Abstract
Significance Vascular mural cells, defined as smooth muscle cells (SMCs) and pericytes, influence brain microcirculation, but how they contribute is not fully understood. Most approaches used to investigate pericyte and capillary interactions include ex vivo retinal/slice preparations or in vivo two-photon microscopy. However, neither method adequately captures mural cell behavior without interfering neuronal tissue. Thus, there is a need to isolate vessels with their respective mural cells to study functional and pathological changes. Aim The aim of our work was to implement an ex vivo method that recapitulates vessel dynamics in the brain. Approach Expanding upon our established ex vivo capillary-parenchymal arteriole (CaPA) preparation, we isolated and pressurized arteriole-capillary branches. Using Alexa Fluor™ 633 Hydrazide, we distinguished arterioles (containing elastin) versus capillaries (lacking elastin). In addition, our transgenic SMMHC-GCaMP6f mice allowed for us to visualize mural cell morphology andCa 2 + signals. Lastly, isolated microvasculature was cultured in DMEM media (up to 72 h), mounted, and pressurized using our CaPA preparation. Results U46619 induced a decrease in capillary lumen diameter using both a bath perfusion and local application. In addition, U46619 increasedCa 2 + signaling both globally and locally in contractile pericytes. In our SMMHC-GCaMP6f mice, we saw that thin strand pericytes had sparse processes while contractile pericytes had long, thick processes that wrapped around the lumen of the capillary. Fresh and cultured pericytes constricted in response to U46619 to the same level, and upstream arteriolar dilation induced by capillary stimulation with 10 mMK + remained unchanged by culture conditions adding another application of longer treatment to our approach. Conclusion Our ex vivo CaPA methodology facilitates observation of arteriolar SMC and pericyte dynamic changes in real-time without environmental factors. This method will help to better understand how mural cells differ based on microvasculature location.
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Affiliation(s)
- Danielle A. Jeffrey
- University of Colorado Anschutz Medical Campus, Department of Anesthesiology, Aurora, Colorado, United States
| | - Jackson T. Fontaine
- University of Colorado Anschutz Medical Campus, Department of Anesthesiology, Aurora, Colorado, United States
| | - Fabrice Dabertrand
- University of Colorado Anschutz Medical Campus, Department of Anesthesiology, Aurora, Colorado, United States
- University of Colorado Anschutz Medical Campus, Department of Pharmacology, Aurora, Colorado, United States
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9
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Korte N, Ilkan Z, Pearson CL, Pfeiffer T, Singhal P, Rock JR, Sethi H, Gill D, Attwell D, Tammaro P. The Ca2+-gated channel TMEM16A amplifies capillary pericyte contraction and reduces cerebral blood flow after ischemia. J Clin Invest 2022; 132:e154118. [PMID: 35316222 PMCID: PMC9057602 DOI: 10.1172/jci154118] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 03/16/2022] [Indexed: 11/26/2022] Open
Abstract
Pericyte-mediated capillary constriction decreases cerebral blood flow in stroke after an occluded artery is unblocked. The determinants of pericyte tone are poorly understood. We show that a small rise in cytoplasmic Ca2+ concentration ([Ca2+]i) in pericytes activated chloride efflux through the Ca2+-gated anion channel TMEM16A, thus depolarizing the cell and opening voltage-gated calcium channels. This mechanism strongly amplified the pericyte [Ca2+]i rise and capillary constriction evoked by contractile agonists and ischemia. In a rodent stroke model, TMEM16A inhibition slowed the ischemia-evoked pericyte [Ca2+]i rise, capillary constriction, and pericyte death; reduced neutrophil stalling; and improved cerebrovascular reperfusion. Genetic analysis implicated altered TMEM16A expression in poor patient recovery from ischemic stroke. Thus, pericyte TMEM16A is a crucial regulator of cerebral capillary function and a potential therapeutic target for stroke and possibly other disorders of impaired microvascular flow, such as Alzheimer's disease and vascular dementia.
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Affiliation(s)
- Nils Korte
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, United Kingdom
| | - Zeki Ilkan
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Claire L. Pearson
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Thomas Pfeiffer
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, United Kingdom
| | - Prabhav Singhal
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, United Kingdom
| | - Jason R. Rock
- Center for Regenerative Medicine, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Huma Sethi
- Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Dipender Gill
- Department of Epidemiology and Biostatistics, St Mary’s Hospital, Imperial College London, London, United Kingdom
| | - David Attwell
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, United Kingdom
| | - Paolo Tammaro
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
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10
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Gagliano G, Monteverdi A, Casali S, Laforenza U, Gandini Wheeler-Kingshott CAM, D’Angelo E, Mapelli L. Non-Linear Frequency Dependence of Neurovascular Coupling in the Cerebellar Cortex Implies Vasodilation-Vasoconstriction Competition. Cells 2022; 11:1047. [PMID: 35326498 PMCID: PMC8947624 DOI: 10.3390/cells11061047] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/11/2022] [Accepted: 03/17/2022] [Indexed: 01/28/2023] Open
Abstract
Neurovascular coupling (NVC) is the process associating local cerebral blood flow (CBF) to neuronal activity (NA). Although NVC provides the basis for the blood oxygen level dependent (BOLD) effect used in functional MRI (fMRI), the relationship between NVC and NA is still unclear. Since recent studies reported cerebellar non-linearities in BOLD signals during motor tasks execution, we investigated the NVC/NA relationship using a range of input frequencies in acute mouse cerebellar slices of vermis and hemisphere. The capillary diameter increased in response to mossy fiber activation in the 6-300 Hz range, with a marked inflection around 50 Hz (vermis) and 100 Hz (hemisphere). The corresponding NA was recorded using high-density multi-electrode arrays and correlated to capillary dynamics through a computational model dissecting the main components of granular layer activity. Here, NVC is known to involve a balance between the NMDAR-NO pathway driving vasodilation and the mGluRs-20HETE pathway driving vasoconstriction. Simulations showed that the NMDAR-mediated component of NA was sufficient to explain the time course of the capillary dilation but not its non-linear frequency dependence, suggesting that the mGluRs-20HETE pathway plays a role at intermediate frequencies. These parallel control pathways imply a vasodilation-vasoconstriction competition hypothesis that could adapt local hemodynamics at the microscale bearing implications for fMRI signals interpretation.
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Affiliation(s)
- Giuseppe Gagliano
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; (G.G.); (A.M.); (S.C.); (C.A.M.G.W.-K.)
| | - Anita Monteverdi
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; (G.G.); (A.M.); (S.C.); (C.A.M.G.W.-K.)
- IRCCS Mondino Foundation, 27100 Pavia, Italy
| | - Stefano Casali
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; (G.G.); (A.M.); (S.C.); (C.A.M.G.W.-K.)
| | - Umberto Laforenza
- Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy;
| | - Claudia A. M. Gandini Wheeler-Kingshott
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; (G.G.); (A.M.); (S.C.); (C.A.M.G.W.-K.)
- IRCCS Mondino Foundation, 27100 Pavia, Italy
- NMR Research Unit, Queen Square MS Centre, Department of Neuroinflammation, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London WC1N3 BG, UK
| | - Egidio D’Angelo
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; (G.G.); (A.M.); (S.C.); (C.A.M.G.W.-K.)
- IRCCS Mondino Foundation, 27100 Pavia, Italy
| | - Lisa Mapelli
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; (G.G.); (A.M.); (S.C.); (C.A.M.G.W.-K.)
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11
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Shaw K, Boyd K, Anderle S, Hammond-Haley M, Amin D, Bonnar O, Hall CN. Gradual Not Sudden Change: Multiple Sites of Functional Transition Across the Microvascular Bed. Front Aging Neurosci 2022; 13:779823. [PMID: 35237142 PMCID: PMC8885127 DOI: 10.3389/fnagi.2021.779823] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Accepted: 12/20/2021] [Indexed: 01/03/2023] Open
Abstract
In understanding the role of the neurovascular unit as both a biomarker and target for disease interventions, it is vital to appreciate how the function of different components of this unit change along the vascular tree. The cells of the neurovascular unit together perform an array of vital functions, protecting the brain from circulating toxins and infection, while providing nutrients and clearing away waste products. To do so, the brain's microvasculature dilates to direct energy substrates to active neurons, regulates access to circulating immune cells, and promotes angiogenesis in response to decreased blood supply, as well as pulsating to help clear waste products and maintain the oxygen supply. Different parts of the cerebrovascular tree contribute differently to various aspects of these functions, and previously, it has been assumed that there are discrete types of vessel along the vascular network that mediate different functions. Another option, however, is that the multiple transitions in function that occur across the vascular network do so at many locations, such that vascular function changes gradually, rather than in sharp steps between clearly distinct vessel types. Here, by reference to new data as well as by reviewing historical and recent literature, we argue that this latter scenario is likely the case and that vascular function gradually changes across the network without clear transition points between arteriole, precapillary arteriole and capillary. This is because classically localized functions are in fact performed by wide swathes of the vasculature, and different functional markers start and stop being expressed at different points along the vascular tree. Furthermore, vascular branch points show alterations in their mural cell morphology that suggest functional specializations irrespective of their position within the network. Together this work emphasizes the need for studies to consider where transitions of different functions occur, and the importance of defining these locations, in order to better understand the vascular network and how to target it to treat disease.
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Affiliation(s)
- Kira Shaw
- Sussex Neuroscience, School of Psychology, University of Sussex, Falmer, United Kingdom
| | - Katie Boyd
- Sussex Neuroscience, School of Psychology, University of Sussex, Falmer, United Kingdom
| | - Silvia Anderle
- Sussex Neuroscience, School of Psychology, University of Sussex, Falmer, United Kingdom
| | | | - Davina Amin
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Orla Bonnar
- MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital and Harvard Medical School, Charlestown Navy Yard, MA, United States
| | - Catherine N. Hall
- Sussex Neuroscience, School of Psychology, University of Sussex, Falmer, United Kingdom
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12
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Walter R, Hunter K, Stenmark K, Kheyfets VO. Hemodynamically Unloading the Distal Pulmonary Circulation in Pulmonary Hypertension: A Modeling Study. J Biomech Eng 2022; 144:024503. [PMID: 34251418 PMCID: PMC8547017 DOI: 10.1115/1.4051719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 07/05/2021] [Indexed: 02/03/2023]
Abstract
Pulmonary hypertension (PH) is a progressive disease that is characterized by a gradual increase in both resistive and reactive pulmonary arterial (PA) impedance. Previous studies in a rodent model of PH have shown that reducing the hemodynamic load in the left lung (by banding the left PA) reverses this remodeling phenomenon. However, banding a single side of the pulmonary circulation is not a viable clinical option, so-using in silico modeling-we evaluated if the banding effect can be recreated by replacing the proximal vasculature with a compliant synthetic PA. We developed a computational model of the pulmonary circulation by combining a one-dimensional model of the proximal vasculature with a zero-dimensional line transmission model to the 12th generation. Using this model, we performed four simulations: (1) Control; (2) PH; (3) PH with a stenosis in the left PA; and (4) PH with proximal vessel compliance returned to Control levels. Simulations revealed that vascular changes associated with PH result in an increase in pulse pressure (PP), maximum pressure (Pmax), maximum wall shear stress (WSS), and maximum circumferential stress (σθθ) relative to controls, in the distal circulation. Banding the left PA reduced these measurements of hemodynamic stress in the left lung, but increases them in the right lung. Furthermore, left PA banding increased reactive PA impedance. However, returning the proximal PA compliance to Control levels simultaneously decreased all measures of hemodynamic stress in both lungs, and returned reactive PA impedance to normal levels. In conclusion, if future in vivo studies support the idea of hemodynamic unloading as an effective therapy for PH, this can be surgically achieved by replacing the proximal PA with a compliant prosthesis, and it will have the added benefit of reducing reactive right ventricular afterload.
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Affiliation(s)
- Rachelle Walter
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Kendall Hunter
- Department of Bioengineering and Department of Pediatrics, University of Colorado Anschutz Medical Campus, Children's Hospital Colorado, Aurora, CO 80045
| | - Kurt Stenmark
- Division of Pediatric Critical Care Medicine and Cardiovascular Pulmonary Research, University of Colorado Anschutz Medical Campus, Children's Hospital Colorado, Aurora, CO 80045
| | - Vitaly O. Kheyfets
- Department of Bioengineering and Department of Pediatrics, University of Colorado Anschutz Medical Campus, Children's Hospital Colorado, Aurora, CO 80045
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13
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Mai-Morente SP, Irigoyen JP, Carriquiry VM, Marset VM, Di Doménico M, Isasi E, Abudara V. Pericyte Mapping in Cerebral Slices with the Far-red Fluorophore TO-PRO-3. Bio Protoc 2021; 11:e4222. [PMID: 34909443 DOI: 10.21769/bioprotoc.4222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 08/11/2021] [Accepted: 08/17/2021] [Indexed: 11/02/2022] Open
Abstract
This protocol describes a method for high-resolution confocal imaging of pericytes with the far-red fluorophore TO-PROTM-3 Iodide 642/661 in cerebral slices of murine. Identification of pericytes with TO-PRO-3 is a short time-consuming, high cost-effective and robust technique to label pericytes with no need for immunostaining or generation of reporter mice. Since the TO-PRO-3 stain resists immunofluorescence, and lacks spectral overlap, the probe is well suited for multiple labelling. Our procedures also combine TO-PRO-3-staining of pericytes with fluorescent markers for astrocytes and vessels in brain slices. These approaches should enable the assessment of pericyte biology in gliovascular unit.
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Affiliation(s)
- Sandra P Mai-Morente
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, General Flores 2125, Montevideo, CP 11 800, Uruguay
| | - Juan P Irigoyen
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, General Flores 2125, Montevideo, CP 11 800, Uruguay
| | - Victoria M Carriquiry
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, General Flores 2125, Montevideo, CP 11 800, Uruguay
| | - Virginia M Marset
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, General Flores 2125, Montevideo, CP 11 800, Uruguay
| | - Mariana Di Doménico
- Departamento de Biofísica, Facultad de Medicina, Universidad de la República, General Flores 2125, Montevideo, CP 11 800, Uruguay
| | - Eugenia Isasi
- Departamento de Histología y Embriología, Facultad de Medicina, Universidad de la República, General Flores 2125, Montevideo, CP 11 800, Uruguay
| | - Verónica Abudara
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, General Flores 2125, Montevideo, CP 11 800, Uruguay
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14
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Li Z, McConnell HL, Stackhouse TL, Pike MM, Zhang W, Mishra A. Increased 20-HETE Signaling Suppresses Capillary Neurovascular Coupling After Ischemic Stroke in Regions Beyond the Infarct. Front Cell Neurosci 2021; 15:762843. [PMID: 34819839 PMCID: PMC8606525 DOI: 10.3389/fncel.2021.762843] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 10/06/2021] [Indexed: 12/23/2022] Open
Abstract
Neurovascular coupling, the process by which neuronal activity elicits increases in the local blood supply, is impaired in stroke patients in brain regions outside the infarct. Such impairment may contribute to neurological deterioration over time, but its mechanism is unknown. Using the middle cerebral artery occlusion (MCAO) model of stroke, we show that neuronal activity-evoked capillary dilation is reduced by ∼75% in the intact cortical tissue outside the infarct border. This decrease in capillary responsiveness was not explained by a decrease in local neuronal activity or a loss of vascular contractility. Inhibiting synthesis of the vasoconstrictive molecule 20-hydroxyeicosatetraenoic acid (20-HETE), either by inhibiting its synthetic enzyme CYP450 ω-hydroxylases or by increasing nitric oxide (NO), which is a natural inhibitor of ω-hydroxylases, rescued activity-evoked capillary dilation. The capillary dilation unmasked by inhibiting 20-HETE was dependent on PGE2 activation of endoperoxide 4 (EP4) receptors, a vasodilatory pathway previously identified in healthy animals. Cortical 20-HETE levels were increased following MCAO, in agreement with data from stroke patients. Inhibition of ω-hydroxylases normalized 20-HETE levels in vivo and increased cerebral blood flow in the peri-infarct cortex. These data identify 20-HETE-dependent vasoconstriction as a mechanism underlying capillary neurovascular coupling impairment after stroke. Our results suggest that the brain's energy supply may be significantly reduced after stroke in regions previously believed to be asymptomatic and that ω-hydroxylase inhibition may restore healthy neurovascular coupling post-stroke.
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Affiliation(s)
- Zhenzhou Li
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States
- Department of Anesthesiology, General Hospital of Ningxia Medical University, Ningxia, China
| | - Heather L. McConnell
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, United States
| | - Teresa L. Stackhouse
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, United States
| | - Martin M. Pike
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR, United States
| | - Wenri Zhang
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR, United States
| | - Anusha Mishra
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, United States
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15
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Evans LE, Taylor JL, Smith CJ, Pritchard HAT, Greenstein AS, Allan SM. Cardiovascular co-morbidities, inflammation and cerebral small vessel disease. Cardiovasc Res 2021; 117:2575-2588. [PMID: 34499123 DOI: 10.1093/cvr/cvab284] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Indexed: 12/15/2022] Open
Abstract
Cerebral small vessel disease (cSVD) is the most common cause of vascular cognitive impairment and affects all levels of the brain's vasculature. Features include diverse structural and functional changes affecting small arteries and capillaries that lead to a decline in cerebral perfusion. Due to an aging population, incidence of cerebral small vessel disease (cSVD) is continually rising. Despite its prevalence and its ability to cause multiple debilitating illnesses, such as stroke and dementia, there are currently no therapeutic strategies for the treatment of cSVD. In the healthy brain, interactions between neuronal, vascular and inflammatory cells are required for normal functioning. When these interactions are disturbed, chronic pathological inflammation can ensue. The interplay between cSVD and inflammation has attracted much recent interest and this review discusses chronic cardiovascular diseases, particularly hypertension, and explores how the associated inflammation may impact on the structure and function of the small arteries of the brain in cSVD. Molecular approaches in animal studies are linked to clinical outcomes in patients and novel hypotheses regarding inflammation and cSVD are proposed that will hopefully stimulate further discussion and study in this important area.
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Affiliation(s)
- Lowri E Evans
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom.,Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance & University of Manchester, Manchester, UK
| | - Jade L Taylor
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom.,Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance & University of Manchester, Manchester, UK
| | - Craig J Smith
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom.,Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance & University of Manchester, Manchester, UK.,Manchester Centre for Clinical Neurosciences, Manchester Academic Health Science Centre, Salford Royal Hospital, Manchester Academic Health Sciences Centre (MAHSC)
| | - Harry A T Pritchard
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom.,Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance & University of Manchester, Manchester, UK
| | - Adam S Greenstein
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom.,Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance & University of Manchester, Manchester, UK
| | - Stuart M Allan
- Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance & University of Manchester, Manchester, UK.,Division of Neuroscience and Experimental Psychology, The University of Manchester, Manchester, UK
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16
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Glück C, Ferrari KD, Binini N, Keller A, Saab AS, Stobart JL, Weber B. Distinct signatures of calcium activity in brain mural cells. eLife 2021; 10:e70591. [PMID: 34227466 PMCID: PMC8294852 DOI: 10.7554/elife.70591] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 06/15/2021] [Indexed: 12/15/2022] Open
Abstract
Pericytes have been implicated in various neuropathologies, yet little is known about their function and signaling pathways in health. Here, we characterized calcium dynamics of cortical mural cells in anesthetized or awake Pdgfrb-CreERT2;Rosa26< LSL-GCaMP6s > mice and in acute brain slices. Smooth muscle cells (SMCs) and ensheathing pericytes (EPs), also named as terminal vascular SMCs, revealed similar calcium dynamics in vivo. In contrast, calcium signals in capillary pericytes (CPs) were irregular, higher in frequency, and occurred in cellular microdomains. In the absence of the vessel constricting agent U46619 in acute slices, SMCs and EPs revealed only sparse calcium signals, whereas CPs retained their spontaneous calcium activity. Interestingly, chemogenetic activation of neurons in vivo and acute elevations of extracellular potassium in brain slices strongly decreased calcium activity in CPs. We propose that neuronal activation and an extracellular increase in potassium suppress calcium activity in CPs, likely mediated by Kir2.2 and KATP channels.
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Affiliation(s)
- Chaim Glück
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
| | - Kim David Ferrari
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
| | - Noemi Binini
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
| | - Annika Keller
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
- Department of Neurosurgery, University of ZurichSchlierenSwitzerland
| | - Aiman S Saab
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
| | - Jillian L Stobart
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Rady Faculty of Health Sciences, College of PharmacyWinnipegCanada
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
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17
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Affiliation(s)
- Michelle E Schober
- Department of Pediatrics, Division of Critical Care, University of Utah, Salt Lake City, UT
| | - Andrew T Pavia
- Department of Infectious Diseases, University of Utah, Salt Lake City, UT
| | - John F Bohnsack
- Department of Rheumatology, University of Utah, Salt Lake City, UT
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18
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Nizari S, Basalay M, Chapman P, Korte N, Korsak A, Christie IN, Theparambil SM, Davidson SM, Reimann F, Trapp S, Yellon DM, Gourine AV. Glucagon-like peptide-1 (GLP-1) receptor activation dilates cerebral arterioles, increases cerebral blood flow, and mediates remote (pre)conditioning neuroprotection against ischaemic stroke. Basic Res Cardiol 2021; 116:32. [PMID: 33942194 PMCID: PMC8093159 DOI: 10.1007/s00395-021-00873-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 04/22/2021] [Indexed: 12/12/2022]
Abstract
Stroke remains one of the most common causes of death and disability worldwide. Several preclinical studies demonstrated that the brain can be effectively protected against ischaemic stroke by two seemingly distinct treatments: remote ischaemic conditioning (RIC), involving cycles of ischaemia/reperfusion applied to a peripheral organ or tissue, or by systemic administration of glucagon-like-peptide-1 (GLP-1) receptor (GLP-1R) agonists. The mechanisms underlying RIC- and GLP-1-induced neuroprotection are not completely understood. In this study, we tested the hypothesis that GLP-1 mediates neuroprotection induced by RIC and investigated the effect of GLP-1R activation on cerebral blood vessels, as a potential mechanism of GLP-1-induced protection against ischaemic stroke. A rat model of ischaemic stroke (90 min of middle cerebral artery occlusion followed by 24-h reperfusion) was used. RIC was induced by 4 cycles of 5 min left hind limb ischaemia interleaved with 5-min reperfusion periods. RIC markedly (by ~ 80%) reduced the cerebral infarct size and improved the neurological score. The neuroprotection established by RIC was abolished by systemic blockade of GLP-1R with a specific antagonist Exendin(9-39). In the cerebral cortex of GLP-1R reporter mice, ~ 70% of cortical arterioles displayed GLP-1R expression. In acute brain slices of the rat cerebral cortex, activation of GLP-1R with an agonist Exendin-4 had a strong dilatory effect on cortical arterioles and effectively reversed arteriolar constrictions induced by metabolite lactate or oxygen and glucose deprivation, as an ex vivo model of ischaemic stroke. In anaesthetised rats, Exendin-4 induced lasting increases in brain tissue PO2, indicative of increased cerebral blood flow. These results demonstrate that neuroprotection against ischaemic stroke established by remote ischaemic conditioning is mediated by a mechanism involving GLP-1R signalling. Potent dilatory effect of GLP-1R activation on cortical arterioles suggests that the neuroprotection in this model is mediated via modulation of cerebral blood flow and improved brain perfusion.
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Affiliation(s)
- Shereen Nizari
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Marina Basalay
- The Hatter Cardiovascular Institute, University College London, London, WC1E 6HX, UK
| | - Philippa Chapman
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Nils Korte
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Alla Korsak
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Isabel N Christie
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Shefeeq M Theparambil
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Sean M Davidson
- The Hatter Cardiovascular Institute, University College London, London, WC1E 6HX, UK
| | - Frank Reimann
- Wellcome Trust/MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Stefan Trapp
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Derek M Yellon
- The Hatter Cardiovascular Institute, University College London, London, WC1E 6HX, UK
| | - Alexander V Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
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19
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Kamen Y, Káradóttir RT. Combining whole-cell patch clamp and dye loading in acute brain slices with bulk RNA sequencing in embryonic to aged mice. STAR Protoc 2021; 2:100439. [PMID: 33899020 PMCID: PMC8055713 DOI: 10.1016/j.xpro.2021.100439] [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: 11/25/2022] Open
Abstract
Single-cell electrophysiological recordings combined with dye loading and immunohistochemistry provide unparalleled single-cell resolution of cell physiology, morphology, location, and protein expression. When correlated with bulk RNA sequencing, these data can define cell identity and function. Here, we describe a protocol to prepare acute brain slices from embryonic and postnatal mice for whole-cell patch clamp, dye loading and post-hoc immunohistochemistry, and cell isolation for bulk RNA sequencing. While we focus on oligodendrocyte precursor cells, this protocol is applicable to other brain cells. For complete details on the use and execution of this protocol, please refer to Spitzer et al. (2019).
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Affiliation(s)
- Yasmine Kamen
- Wellcome – Medical Research Council Cambridge Stem Cell Institute and Department of Veterinary Medicine, University of Cambridge, Cambridge CB2 0AW, United Kingdom,Corresponding author
| | - Ragnhildur Thóra Káradóttir
- Wellcome – Medical Research Council Cambridge Stem Cell Institute and Department of Veterinary Medicine, University of Cambridge, Cambridge CB2 0AW, United Kingdom,Department of Physiology, Biomedical Centre, Faculty of Medicine, University of Iceland, Reykjavik, Iceland,Corresponding author
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20
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Dragoni S, Caridi B, Karatsai E, Burgoyne T, Sarker MH, Turowski P. AMP-activated protein kinase is a key regulator of acute neurovascular permeability. J Cell Sci 2021; 134:jcs253179. [PMID: 33712448 PMCID: PMC8077405 DOI: 10.1242/jcs.253179] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 03/02/2021] [Indexed: 12/11/2022] Open
Abstract
Many neuronal and retinal disorders are associated with pathological hyperpermeability of the microvasculature. We have used explants of rodent retinae to study acute neurovascular permeability, signal transduction and the role of AMP-activated protein kinase (AMPK). Following stimulation with either vascular endothelial growth factor (VEGF-A) or bradykinin (BK), AMPK was rapidly and strongly phosphorylated and acted as a key mediator of permeability downstream of Ca2+. Accordingly, AMPK agonists potently induced acute retinal vascular leakage. AMPK activation led to phosphorylation of endothelial nitric oxide synthase (eNOS, also known as NOS3), which in turn increased VE-cadherin (CDH5) phosphorylation on Y685. In parallel, AMPK also mediated phosphorylation of p38 MAP kinases (hereafter p38) and HSP27 (HSPB1), indicating that it regulated paracellular junctions and cellular contractility, both previously associated with endothelial permeability. Endothelial AMPK provided a missing link in neurovascular permeability, connecting Ca2+ transients to the activation of eNOS and p38, irrespective of the permeability-inducing factor used. Collectively, we find that, due to its compatibility with small molecule antagonists and agonists, as well as siRNA, the ex vivo retina model constitutes a reliable tool to identify and study regulators and mechanisms of acute neurovascular permeability.
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Affiliation(s)
- Silvia Dragoni
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Bruna Caridi
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Eleni Karatsai
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Thomas Burgoyne
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Mosharraf H. Sarker
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
- School of Science, Engineering & Design, Teesside University, Stephenson Street, Middlesbrough TS1 3BA, UK
| | - Patric Turowski
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
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21
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McDowell KP, Berthiaume AA, Tieu T, Hartmann DA, Shih AY. VasoMetrics: unbiased spatiotemporal analysis of microvascular diameter in multi-photon imaging applications. Quant Imaging Med Surg 2021; 11:969-982. [PMID: 33654670 PMCID: PMC7829163 DOI: 10.21037/qims-20-920] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 11/17/2020] [Indexed: 01/13/2023]
Abstract
BACKGROUND Multi-photon imaging of the cerebrovasculature provides rich data on the dynamics of cortical arterioles, capillaries, and venules. Vascular diameter is the major determinant of blood flow resistance, and is the most commonly quantified metric in studies of the cerebrovasculature. However, there is a lack of accessible and easy-to-use methods to quantify vascular diameter in imaging data. METHODS We created VasoMetrics, a macro written in ImageJ/Fiji for spatiotemporal analysis of microvascular diameter. The key feature of VasoMetrics is rapid analysis of many evenly spaced cross-sectional lines along the vessel of interest, permitting the extraction of numerous diameter measurements from individual vessels. Here we demonstrated the utility of VasoMetrics by analyzing in vivo multi-photon imaging stacks and movies collected from lightly sedated mice, as well as data from optical coherence tomography angiography (OCTA) of human retina. RESULTS Compared to the standard approach, which is to measure cross-sectional diameters at arbitrary points along a vessel, VasoMetrics accurately reported spatiotemporal features of vessel diameter, reduced measurement bias and time spent analyzing data, and improved the reproducibility of diameter measurements between users. VasoMetrics revealed the dynamics in pial arteriole diameters during vasomotion at rest, as well as changes in capillary diameter before and after pericyte ablation. Retinal arteriole diameter was quantified from a human retinal angiogram, providing proof-of-principle that VasoMetrics can be applied to contrast-enhanced clinical imaging of microvasculature. CONCLUSIONS VasoMetrics is a robust macro for spatiotemporal analysis of microvascular diameter in imaging applications.
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Affiliation(s)
- Konnor P. McDowell
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Andrée-Anne Berthiaume
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, WA, USA
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Taryn Tieu
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, WA, USA
| | - David A. Hartmann
- Department of Neurology & Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Andy Y. Shih
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, WA, USA
- Department of Pediatrics, University of Washington, Seattle, WA, USA
- Department of Bioengineering, University of Washington, Seattle, WA, USA
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22
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Lee LL, Khakoo AY, Chintalgattu V. Cardiac pericytes function as key vasoactive cells to regulate homeostasis and disease. FEBS Open Bio 2020; 11:207-225. [PMID: 33135334 PMCID: PMC7780101 DOI: 10.1002/2211-5463.13021] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 08/24/2020] [Accepted: 10/30/2020] [Indexed: 01/13/2023] Open
Abstract
Pericytes (PCs)—mural cells that envelop endothelial cells (ECs) of microvessels—regulate tissue‐specific vasculature development as well as maturation and maintenance of endothelial barrier integrity. However, little is known about their tissue‐specific function in the heart. Specifically, the mechanism by which cardiac PCs constrict coronary capillaries remains undetermined. To gain insights into the function of cardiac PCs at the cellular level, we isolated NG2+ PDGFRβ+ CD146+ CD34− CD31− CD45− PCs for detailed characterization. Functionally, we provide evidence that these PCs increased transepithelial electrical resistance and decreased endothelial permeability. We show for the first time that this population of PCs express contractile proteins, are stimulated by adrenergic signaling, and demonstrate stereotypical contraction and relaxation. Furthermore, we also studied for the first time, the PCs in in vitro models of disease. PCs in hypoxia activated the hypoxia‐inducible factor 1 alpha pathway, increased secretion of angiogenic factors, and caused cellular apoptosis. Supraphysiological levels of low‐density lipoprotein decreased PC proliferation and induced lipid droplet accumulation. Elevated glucose levels triggered a proinflammatory response. Taken together, our study characterizes cardiac PCs under in vitro disease conditions and supports the hypothesis that cardiac PCs are key vasoactive cells that can regulate blood flow in the heart.
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Affiliation(s)
- Linda L Lee
- Department of Cardiometabolic Disorders, Amgen Research and Discovery, Amgen Inc., South San Francisco, CA, USA
| | - Aarif Y Khakoo
- Department of Drug Development, Calico Labs, South San Francisco, CA, USA
| | - Vishnu Chintalgattu
- Department of Cardiometabolic Disorders, Amgen Research and Discovery, Amgen Inc., South San Francisco, CA, USA
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23
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Kaul S, Methner C, Mishra A. The role of pericytes in hyperemia-induced capillary de-recruitment following stenosis. ACTA ACUST UNITED AC 2020; 1:163-169. [PMID: 33778770 DOI: 10.1007/s43152-020-00017-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Purpose The microvascular capillary network is ensheathed by cells called pericytes - a heterogeneous population of mural cells derived from multiple lineages. Pericytes play a multifaceted role in the body, including in vascular structure and permeability, regulation of local blood flow, immune and wound healing functions, induction of angiogenesis, and generation of various progenitor cells. Here, we consider the role of pericytes in capillary de-recruitment, a pathophysiologic phenomenon that is observed following hyperemic stimuli in the presence of a stenosis and attenuates the hyperemic response. Recent Findings We discuss recent observations that conclusively demonstrate pericytes to be the cellular structures that contract in response to hyperemic stimuli when an upstream arterial stenosis is present. This response constricts capillaries, which is likely aimed at maintaining capillary hydrostatic pressure, an important factor in tissue homeostasis. Nonetheless, the ensuing attenuation of the hyperemic response can lead to a decrease in energy supply and negatively impact tissue health. Summary Therapeutics aimed at preventing pericyte-mediated capillary de-recruitment may prove beneficial in conditions such as coronary stenosis and peripheral arterial disease by reducing restriction in hyperemic flow. Identification of the pericyte subtypes involved in this de-recruitment and the underlying molecular mechanisms regulating this process will greatly assist this purpose.
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Affiliation(s)
- Sanjiv Kaul
- Knight Cardiovascular Institute Oregon Health & Science University, Portland, Oregon, USA
| | - Carmen Methner
- Knight Cardiovascular Institute Oregon Health & Science University, Portland, Oregon, USA
| | - Anusha Mishra
- Knight Cardiovascular Institute Oregon Health & Science University, Portland, Oregon, USA.,Jungers Center for Neurosciences Research, Department of Neurology, Oregon Health & Science University, Portland, Oregon, USA
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24
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Mai-Morente SP, Marset VM, Blanco F, Isasi EE, Abudara V. A nuclear fluorescent dye identifies pericytes at the neurovascular unit. J Neurochem 2020; 157:1377-1391. [PMID: 32974913 DOI: 10.1111/jnc.15193] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 08/27/2020] [Accepted: 09/14/2020] [Indexed: 11/26/2022]
Abstract
Perivascular pericytes are key regulators of the blood-brain barrier, vascular development, and cerebral blood flow. Deciphering pericyte roles in health and disease requires cellular tracking; yet, pericyte identification remains challenging. A previous study reported that the far-red fluorophore TO-PRO-3 (642/661), usually employed as a nuclear dye in fixed tissue, was selectively captured by live pericytes from the subventricular zone. Herein, we validated TO-PRO-3 as a specific pericyte tracer in the nervous system (NS). Living pericytes from ex vivo murine hippocampus, cortex, spinal cord, and retina robustly incorporated TO-PRO-3. Classical pericyte immunomarkers such as chondroitin sulphate proteoglycan neuron-glial antigen 2 (NG2) and platelet-derived growth factor receptor beta antigen (PDGFrβ) and the new pericyte dye NeuroTrace 500/525 confirmed cellular specificity of dye uptake. The TO-PRO-3 signal enabled quantification of pericytes density and morphometry; likewise, TO-PRO-3 labeling allowed visualization of pericytes associated with other components of the neurovascular unit. A subset of TO-PRO-3 stained cells expressed the contractile protein α-SMA, indicative of their ability to control the capillary diameter. Uptake of TO-PRO-3 was independent of connexin/pannexin channels but was highly sensitive to temperature and showed saturation, suggesting that a yet unidentified protein-mediated active transport sustained dye incorporation. We conclude that TO-PRO-3 labeling provides a reliable and simple tool for the bioimaging of pericytes in the murine NS microvasculature.
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Affiliation(s)
- Sandra P Mai-Morente
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Virginia M Marset
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Fabiana Blanco
- Departamento de Biofísica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Eugenia E Isasi
- Departamento de Histología y Embriología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Verónica Abudara
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
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25
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Contractile pericytes determine the direction of blood flow at capillary junctions. Proc Natl Acad Sci U S A 2020; 117:27022-27033. [PMID: 33051294 DOI: 10.1073/pnas.1922755117] [Citation(s) in RCA: 110] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The essential function of the circulatory system is to continuously and efficiently supply the O2 and nutrients necessary to meet the metabolic demands of every cell in the body, a function in which vast capillary networks play a key role. Capillary networks serve an additional important function in the central nervous system: acting as a sensory network, they detect neuronal activity in the form of elevated extracellular K+ and initiate a retrograde, propagating, hyperpolarizing signal that dilates upstream arterioles to rapidly increase local blood flow. Yet, little is known about how blood entering this network is distributed on a branch-to-branch basis to reach specific neurons in need. Here, we demonstrate that capillary-enwrapping projections of junctional, contractile pericytes within a postarteriole transitional region differentially constrict to structurally and dynamically determine the morphology of capillary junctions and thereby regulate branch-specific blood flow. We further found that these contractile pericytes are capable of receiving propagating K+-induced hyperpolarizing signals propagating through the capillary network and dynamically channeling red blood cells toward the initiating signal. By controlling blood flow at junctions, contractile pericytes within a functionally distinct postarteriole transitional region maintain the efficiency and effectiveness of the capillary network, enabling optimal perfusion of the brain.
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26
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He Y, Wang M, Yu X. High spatiotemporal vessel-specific hemodynamic mapping with multi-echo single-vessel fMRI. J Cereb Blood Flow Metab 2020; 40:2098-2114. [PMID: 31696765 PMCID: PMC7786852 DOI: 10.1177/0271678x19886240] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
High-resolution fMRI enables noninvasive mapping of the hemodynamic responses from individual penetrating vessels in animal brains. Here, a 2D multi-echo single-vessel fMRI (MESV-fMRI) method has been developed to map the fMRI signal from arterioles and venules with a 100 ms sampling rate at multiple echo times (TE, 3-30 ms) and short acquisition windows (<1 ms). The T2*-weighted signal shows the increased extravascular effect on venule voxels as a function of TE. In contrast, the arteriole voxels show an increased fMRI signal with earlier onset than venules voxels at the short TE (3 ms) with increased blood inflow and volume effects. MESV-fMRI enables vessel-specific T2* mapping and presents T2*-based fMRI time courses with higher contrast-to-noise ratios (CNRs) than the T2*-weighted fMRI signal at a given TE. The vessel-specific T2* mapping also allows semi-quantitative estimation of the oxygen saturation levels (Y) and their changes (ΔY) at a given blood volume fraction upon neuronal activation. The MESV-fMRI method enables vessel-specific T2* measurements with high spatiotemporal resolution for better modeling of the fMRI signal based on the hemodynamic parameters.
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Affiliation(s)
- Yi He
- Translational Neuroimaging and Neural Control Group, High Field Magnetic Resonance Department, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany.,Graduate Training Centre of Neuroscience, International Max Planck Research School, University of Tuebingen, Tuebingen, Germany.,Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
| | - Maosen Wang
- Translational Neuroimaging and Neural Control Group, High Field Magnetic Resonance Department, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany.,Graduate Training Centre of Neuroscience, International Max Planck Research School, University of Tuebingen, Tuebingen, Germany
| | - Xin Yu
- Translational Neuroimaging and Neural Control Group, High Field Magnetic Resonance Department, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany.,Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
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27
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Špiranec Spes K, Chen W, Krebes L, Völker K, Abeßer M, Eder Negrin P, Cellini A, Nickel A, Nikolaev VO, Hofmann F, Schuh K, Schweda F, Kuhn M. Heart-Microcirculation Connection: Effects of ANP (Atrial Natriuretic Peptide) on Pericytes Participate in the Acute and Chronic Regulation of Arterial Blood Pressure. Hypertension 2020; 76:1637-1648. [PMID: 32951468 DOI: 10.1161/hypertensionaha.120.15772] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cardiac ANP (atrial natriuretic peptide) moderates arterial blood pressure. The mechanisms mediating its hypotensive effects are complex and involve inhibition of the renin-angiotensin-aldosterone system, increased natriuresis, endothelial permeability, and vasodilatation. The contribution of the direct vasodilating effects of ANP to blood pressure homeostasis is controversial because variable levels of the ANP receptor, GC-A (guanylyl cyclase-A), are expressed among vascular beds. Here, we show that ANP stimulates GC-A/cyclic GMP signaling in cultured microvascular pericytes and thereby the phosphorylation of the regulatory subunit of myosin phosphatase 1 by cGMP-dependent protein kinase I. Moreover, ANP prevents the calcium and contractile responses of pericytes to endothelin-1 as well as microvascular constrictions. In mice with conditional inactivation (knock-out) of GC-A in microcirculatory pericytes, such vasodilating effects of ANP on precapillary arterioles and capillaries were fully abolished. Concordantly, these mice have increased blood pressure despite preserved renal excretory function. Furthermore, acute intravascular volume expansion, which caused release of cardiac ANP, did not affect blood pressure of control mice but provoked hypertensive reactions in pericyte GC-A knock-out littermates. We conclude that GC-A/cGMP-dependent modulation of pericytes and microcirculatory tone contributes to the acute and chronic moderation of arterial blood pressure by ANP. Graphic Abstract A graphic abstract is available for this article.
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Affiliation(s)
- Katarina Špiranec Spes
- From the Institute of Physiology, University of Würzburg (K.S.S., W.C., L.K., K.V., M.A., K.S., M.K.), University Hospital Würzburg, Germany.,Comprehensive Heart Failure Center (K.S.S., W.C., P.E.N., A.C., A.N., M.K.), University Hospital Würzburg, Germany
| | - Wen Chen
- From the Institute of Physiology, University of Würzburg (K.S.S., W.C., L.K., K.V., M.A., K.S., M.K.), University Hospital Würzburg, Germany.,Comprehensive Heart Failure Center (K.S.S., W.C., P.E.N., A.C., A.N., M.K.), University Hospital Würzburg, Germany.,The Affiliated Haimen Hospital, Nantong University, Jiangsu, China (W.C.)
| | - Lisa Krebes
- From the Institute of Physiology, University of Würzburg (K.S.S., W.C., L.K., K.V., M.A., K.S., M.K.), University Hospital Würzburg, Germany
| | - Katharina Völker
- From the Institute of Physiology, University of Würzburg (K.S.S., W.C., L.K., K.V., M.A., K.S., M.K.), University Hospital Würzburg, Germany
| | - Marco Abeßer
- From the Institute of Physiology, University of Würzburg (K.S.S., W.C., L.K., K.V., M.A., K.S., M.K.), University Hospital Würzburg, Germany
| | - Petra Eder Negrin
- Comprehensive Heart Failure Center (K.S.S., W.C., P.E.N., A.C., A.N., M.K.), University Hospital Würzburg, Germany
| | - Antonella Cellini
- Comprehensive Heart Failure Center (K.S.S., W.C., P.E.N., A.C., A.N., M.K.), University Hospital Würzburg, Germany
| | - Alexander Nickel
- Comprehensive Heart Failure Center (K.S.S., W.C., P.E.N., A.C., A.N., M.K.), University Hospital Würzburg, Germany
| | - Viacheslav O Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Germany (V.O.N.)
| | - Franz Hofmann
- Institute of Pharmacology and Toxicology, TU Munich, Germany (F.H.)
| | - Kai Schuh
- From the Institute of Physiology, University of Würzburg (K.S.S., W.C., L.K., K.V., M.A., K.S., M.K.), University Hospital Würzburg, Germany
| | - Frank Schweda
- Institute of Physiology, University of Regensburg, Germany (F.S.)
| | - Michaela Kuhn
- From the Institute of Physiology, University of Würzburg (K.S.S., W.C., L.K., K.V., M.A., K.S., M.K.), University Hospital Würzburg, Germany
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28
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Cleary CM, Moreira TS, Takakura AC, Nelson MT, Longden TA, Mulkey DK. Vascular control of the CO 2/H +-dependent drive to breathe. eLife 2020; 9:e59499. [PMID: 32924935 PMCID: PMC7521922 DOI: 10.7554/elife.59499] [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: 05/29/2020] [Accepted: 09/14/2020] [Indexed: 12/17/2022] Open
Abstract
Respiratory chemoreceptors regulate breathing in response to changes in tissue CO2/H+. Blood flow is a fundamental determinant of tissue CO2/H+, yet little is known regarding how regulation of vascular tone in chemoreceptor regions contributes to respiratory behavior. Previously, we showed in rat that CO2/H+-vasoconstriction in the retrotrapezoid nucleus (RTN) supports chemoreception by a purinergic-dependent mechanism (Hawkins et al., 2017). Here, we show in mice that CO2/H+ dilates arterioles in other chemoreceptor regions, thus demonstrating CO2/H+ vascular reactivity in the RTN is unique. We also identify P2Y2 receptors in RTN smooth muscle cells as the substrate responsible for this response. Specifically, pharmacological blockade or genetic deletion of P2Y2 from smooth muscle cells blunted the ventilatory response to CO2, and re-expression of P2Y2 receptors only in RTN smooth muscle cells fully rescued the CO2/H+ chemoreflex. These results identify P2Y2 receptors in RTN smooth muscle cells as requisite determinants of respiratory chemoreception.
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MESH Headings
- Animals
- Carbon Dioxide/metabolism
- Chemoreceptor Cells/metabolism
- Hydrogen/metabolism
- Medulla Oblongata/physiology
- Mice
- Mice, Knockout
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/physiology
- Receptors, Purinergic P2Y2/genetics
- Receptors, Purinergic P2Y2/metabolism
- Receptors, Purinergic P2Y2/physiology
- Respiration
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Affiliation(s)
- Colin M Cleary
- Department of Physiology and Neurobiology, University of ConnecticutStorrsUnited States
| | - Thiago S Moreira
- Department of Physiology and Biophysics, University of São PauloSão PauloBrazil
| | - Ana C Takakura
- Department of Pharmacology, University of São PauloSão PauloBrazil
| | - Mark T Nelson
- Department of Pharmacology, University of VermontBurlingtonUnited States
- Institute of Cardiovascular SciencesManchesterUnited Kingdom
| | - Thomas A Longden
- Department of Physiology, University of MarylandBaltimoreUnited States
| | - Daniel K Mulkey
- Department of Physiology and Neurobiology, University of ConnecticutStorrsUnited States
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29
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Maliszewska-Cyna E, Vecchio LM, Thomason LAM, Oore JJ, Steinman J, Joo IL, Dorr A, McLaurin J, Sled JG, Stefanovic B, Aubert I. The effects of voluntary running on cerebrovascular morphology and spatial short-term memory in a mouse model of amyloidosis. Neuroimage 2020; 222:117269. [PMID: 32818618 DOI: 10.1016/j.neuroimage.2020.117269] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/06/2020] [Accepted: 08/10/2020] [Indexed: 12/27/2022] Open
Abstract
Physical activity has been correlated with a reduced risk of cognitive decline, including that associated with vascular dementia, mild cognitive impairment (MCI) and Alzheimer's disease (AD); recent literature suggests this may in part result from benefits to the cerebrovascular network. Using a transgenic (Tg) mouse model of AD, we evaluated the effect of running on cortical and hippocampal vascular morphology, cerebral amyloid angiopathy, amyloid plaque load, and spatial memory. TgCRND8 mice present with progressive amyloid pathology, advancing from the cortex to the hippocampus in a time-dependent manner. We postulated that the characteristic progression of pathology could lead to differential, time-dependent effects of physical activity on vascular morphology in these brain regions at 6 months of age. We used two-photon fluorescent microscopy and 3D vessel tracking to characterize vascular and amyloid pathology in sedentary TgCRND8 mice compared those who have a history of physical activity (unlimited access to a running wheel, from 3 to 6 months of age). In sedentary TgCRND8 mice, capillary density was found to be lower in the cortex and higher in the hippocampus compared to non-transgenic (nonTg) littermates. Capillary length, vessel branching, and non-capillary vessel tortuosity were also higher in the hippocampus of sedentary TgCRND8 compared to nonTg mice. Three months of voluntary running resulted in normalizing cortical and hippocampal microvascular morphology, with no significant difference between TgCRND8 and nonTg mice. The benefits of physical activity on cortical and hippocampal vasculature in 6-month old TgCRND8 mice were not paralleled by significant changes on parenchymal and cerebral amyloid pathology. Short-term spatial memory- as evaluated by performance in the Y-maze- was significantly improved in running compared to sedentary TgCRND8 mice. These results suggest that long-term voluntary running contributes to the maintenance of vascular morphology and spatial memory in TgCRND8 mice, even in the absence of an effect on amyloid pathology.
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Affiliation(s)
- Ewelina Maliszewska-Cyna
- Hurvitz Brain Sciences, Biological Sciences, Sunnybrook Research Institute, 2075 Bayview Ave, S112, Toronto, Ontario M4N 3M5, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Laura M Vecchio
- Hurvitz Brain Sciences, Biological Sciences, Sunnybrook Research Institute, 2075 Bayview Ave, S112, Toronto, Ontario M4N 3M5, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada.
| | - Lynsie A M Thomason
- Hurvitz Brain Sciences, Physical Sciences, Sunnybrook Research Institute, Canada
| | - Jonathan J Oore
- Hurvitz Brain Sciences, Biological Sciences, Sunnybrook Research Institute, 2075 Bayview Ave, S112, Toronto, Ontario M4N 3M5, Canada
| | - Joe Steinman
- Mouse Imaging Centre, Hospital for Sick Children, Canada; Department of Medical Biophysics, University of Toronto, Canada
| | - Illsung Lewis Joo
- Hurvitz Brain Sciences, Physical Sciences, Sunnybrook Research Institute, Canada
| | - Adrienne Dorr
- Hurvitz Brain Sciences, Physical Sciences, Sunnybrook Research Institute, Canada
| | - JoAnne McLaurin
- Hurvitz Brain Sciences, Biological Sciences, Sunnybrook Research Institute, 2075 Bayview Ave, S112, Toronto, Ontario M4N 3M5, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - John G Sled
- Mouse Imaging Centre, Hospital for Sick Children, Canada; Department of Medical Biophysics, University of Toronto, Canada
| | - Bojana Stefanovic
- Hurvitz Brain Sciences, Physical Sciences, Sunnybrook Research Institute, Canada; Department of Medical Biophysics, University of Toronto, Canada
| | - Isabelle Aubert
- Hurvitz Brain Sciences, Biological Sciences, Sunnybrook Research Institute, 2075 Bayview Ave, S112, Toronto, Ontario M4N 3M5, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
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30
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Ding R, Hase Y, Ameen-Ali KE, Ndung'u M, Stevenson W, Barsby J, Gourlay R, Akinyemi T, Akinyemi R, Uemura MT, Polvikoski T, Mukaetova-Ladinska E, Ihara M, Kalaria RN. Loss of capillary pericytes and the blood-brain barrier in white matter in poststroke and vascular dementias and Alzheimer's disease. Brain Pathol 2020; 30:1087-1101. [PMID: 32705757 PMCID: PMC8018063 DOI: 10.1111/bpa.12888] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 06/29/2020] [Accepted: 08/14/2020] [Indexed: 02/06/2023] Open
Abstract
White matter (WM) disease is associated with disruption of the gliovascular unit, which involves breach of the blood–brain barrier (BBB). We quantified pericytes as components of the gliovascular unit and assessed their status in vascular and other common dementias. Immunohistochemical and immunofluorescent methods were developed to assess the distribution and quantification of pericytes connected to the frontal lobe WM capillaries. Pericytes with a nucleus were identified by collagen 4 (COL4) and platelet‐derived growth factor receptor‐β (PDGFR‐β) antibodies with further verification using PDGFR‐β‐specific ELISA. We evaluated a total of 124 post‐mortem brains from subjects with post‐stroke dementia (PSD), vascular dementia (VaD), Alzheimer’s disease (AD), AD‐VaD (Mixed) and post‐stroke non‐demented (PSND) stroke survivors as well as normal aging controls. COL4 and PDGFR‐β reactive pericytes adopted the characteristic “crescent” or nodule‐like shapes around capillary walls. We estimated densities of pericyte somata to be 225 ±38 and 200 ±13 (SEM) per COL4 mm2 area or 2.0 ± 0.1 and 1.7 ± 0.1 per mm capillary length in young and older aging controls. Remarkably, WM pericytes were reduced by ~35%–45% in the frontal lobe of PSD, VaD, Mixed and AD subjects compared to PSND and controls subjects (P < 0.001). We also found pericyte numbers were correlated with PDGFR‐β reactivity in the WM. Our results first demonstrate a reliable method to quantify COL4‐positive pericytes and then, indicate that deep WM pericytes are decreased across different dementias including PSD, VaD, Mixed and AD. Our findings suggest that downregulation of pericytes is associated with the disruption of the BBB in the deep WM in several aging‐related dementias.
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Affiliation(s)
- Ren Ding
- Neurovascular Research Group, Translational and Clinical Research Institute, Newcastle University, Campus for Ageing & Vitality, Newcastle Upon Tyne, UK
| | - Yoshiki Hase
- Neurovascular Research Group, Translational and Clinical Research Institute, Newcastle University, Campus for Ageing & Vitality, Newcastle Upon Tyne, UK
| | - Kamar E Ameen-Ali
- Neurovascular Research Group, Translational and Clinical Research Institute, Newcastle University, Campus for Ageing & Vitality, Newcastle Upon Tyne, UK
| | - Michael Ndung'u
- Neurovascular Research Group, Translational and Clinical Research Institute, Newcastle University, Campus for Ageing & Vitality, Newcastle Upon Tyne, UK
| | - William Stevenson
- Neurovascular Research Group, Translational and Clinical Research Institute, Newcastle University, Campus for Ageing & Vitality, Newcastle Upon Tyne, UK
| | - Joseph Barsby
- Neurovascular Research Group, Translational and Clinical Research Institute, Newcastle University, Campus for Ageing & Vitality, Newcastle Upon Tyne, UK
| | - Ryan Gourlay
- Neurovascular Research Group, Translational and Clinical Research Institute, Newcastle University, Campus for Ageing & Vitality, Newcastle Upon Tyne, UK
| | - Tolulope Akinyemi
- Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - Rufus Akinyemi
- Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - Maiko T Uemura
- Institute on Aging and Center for Neurodegenerative Disease Research, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Tuomo Polvikoski
- Neurovascular Research Group, Translational and Clinical Research Institute, Newcastle University, Campus for Ageing & Vitality, Newcastle Upon Tyne, UK
| | | | - Masafumi Ihara
- Department of Neurology, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Raj N Kalaria
- Neurovascular Research Group, Translational and Clinical Research Institute, Newcastle University, Campus for Ageing & Vitality, Newcastle Upon Tyne, UK
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31
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Lee S, Chung M, Lee SR, Jeon NL. 3D brain angiogenesis model to reconstitute functional human blood-brain barrier in vitro. Biotechnol Bioeng 2019; 117:748-762. [PMID: 31709508 DOI: 10.1002/bit.27224] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 10/10/2019] [Accepted: 11/04/2019] [Indexed: 01/01/2023]
Abstract
The human central nervous system (CNS) vasculature expresses a distinctive barrier phenotype, the blood-brain barrier (BBB). As the BBB contributes to low efficiency in CNS pharmacotherapy by restricting drug transport, the development of an in vitro human BBB model has been in demand. Here, we present a microfluidic model of CNS angiogenesis having three-dimensional (3D) lumenized vasculature in concert with perivascular cells. We confirmed the necessity of the angiogenic tri-culture system (brain endothelium in direct interaction with pericytes and astrocytes) to attain essential phenotypes of BBB vasculature, such as minimized vessel diameter and maximized junction expression. In addition, lower vascular permeability is achieved in the tri-culture condition compared to the monoculture condition. Notably, we focussed on reconstituting the functional efflux transporter system, including p-glycoprotein (p-gp), which is highly responsible for restrictive drug transport. By conducting the calcein-AM efflux assay on our 3D perfusable vasculature after treatment of efflux transporter inhibitors, we confirmed the higher efflux property and prominent effect of inhibitors in the tri-culture model. Taken together, we designed a 3D human BBB model with functional barrier properties based on a developmentally inspired CNS angiogenesis protocol. We expect the model to contribute to a deeper understanding of pathological CNS angiogenesis and the development of effective CNS medications.
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Affiliation(s)
- Somin Lee
- Program for Bioengineering, Seoul National University, Seoul, Korea
| | - Minhwan Chung
- Mechanical Engineering, Seoul National University, Seoul, Korea
| | - Seung-Ryeol Lee
- Mechanical Engineering, Seoul National University, Seoul, Korea
| | - Noo Li Jeon
- Program for Bioengineering, Seoul National University, Seoul, Korea.,Mechanical Engineering, Seoul National University, Seoul, Korea.,Institute of Advanced Machines and Design, Seoul National University, Seoul, Korea.,Institute of Bioengineering, Seoul National University, Seoul, Korea
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32
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Excess Glutamate May Cause Dilation of Retinal Blood Vessels in Glutamate/Aspartate Transporter-Deficient Mice. BIOMED RESEARCH INTERNATIONAL 2019; 2019:6512195. [PMID: 31828115 PMCID: PMC6881573 DOI: 10.1155/2019/6512195] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Accepted: 10/22/2019] [Indexed: 11/18/2022]
Abstract
Purpose To investigate the longitudinal findings of fundus features and spectral-domain optical coherence tomography (SD-OCT) to characterize the morphologic features in a mouse model of defective glutamate/aspartate transporter (GLAST−/− mice). Materials and Methods The fundus findings and SD-OCT images were longitudinally recorded at five time points from postnatal (P) 22 to P156 in GLAST−/− mice. As a control wild type, age-matched C57BL/6J mice were employed. The mouse retina was subdivided into five layers, and the thickness of each layer was longitudinally measured by InSight® using SD-OCT pictures. The SD-OCT findings were compared with the histologic appearances. The diameter of the retinal blood vessels was measured by the ImageJ® software program using SD-OCT images. The data were statistically compared between both age-matched mouse groups. Results The retinal blood vessels appeared more dilated in GLAST−/− mice than in wild-type mice. This tendency was statistically significant at all time points after P44 by analyses using SD-OCT images. The ganglion cell complex (GCC) and outer nuclear layer (ONL) were significantly thinner in GLAST−/− mice at all time points after P80 than in the wild-type mice. This tendency was more clearly indicated by SD-OCT than histologic sections. Discussion In the present study, we found for the first time the dilation of the retinal blood vessels and the thinning of the ONL in GLAST−/− mice, in addition to the thinning of the GCC.
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Payne LB, Zhao H, James CC, Darden J, McGuire D, Taylor S, Smyth JW, Chappell JC. The pericyte microenvironment during vascular development. Microcirculation 2019; 26:e12554. [PMID: 31066166 PMCID: PMC6834874 DOI: 10.1111/micc.12554] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 04/29/2019] [Accepted: 05/03/2019] [Indexed: 12/22/2022]
Abstract
Vascular pericytes provide critical contributions to the formation and integrity of the blood vessel wall within the microcirculation. Pericytes maintain vascular stability and homeostasis by promoting endothelial cell junctions and depositing extracellular matrix (ECM) components within the vascular basement membrane, among other vital functions. As their importance in sustaining microvessel health within various tissues and organs continues to emerge, so does their role in a number of pathological conditions including cancer, diabetic retinopathy, and neurological disorders. Here, we review vascular pericyte contributions to the development and remodeling of the microcirculation, with a focus on the local microenvironment during these processes. We discuss observations of their earliest involvement in vascular development and essential cues for their recruitment to the remodeling endothelium. Pericyte involvement in the angiogenic sprouting context is also considered with specific attention to crosstalk with endothelial cells such as through signaling regulation and ECM deposition. We also address specific aspects of the collective cell migration and dynamic interactions between pericytes and endothelial cells during angiogenic sprouting. Lastly, we discuss pericyte contributions to mechanisms underlying the transition from active vessel remodeling to the maturation and quiescence phase of vascular development.
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Affiliation(s)
- Laura Beth Payne
- Center for Heart and Reparative Medicine, Fralin Biomedical Research Institute, Roanoke, VA 24016, USA
| | - Huaning Zhao
- Center for Heart and Reparative Medicine, Fralin Biomedical Research Institute, Roanoke, VA 24016, USA
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic State Institute and State University, Blacksburg, VA 24061, USA
| | - Carissa C. James
- Center for Heart and Reparative Medicine, Fralin Biomedical Research Institute, Roanoke, VA 24016, USA
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Jordan Darden
- Center for Heart and Reparative Medicine, Fralin Biomedical Research Institute, Roanoke, VA 24016, USA
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - David McGuire
- Center for Heart and Reparative Medicine, Fralin Biomedical Research Institute, Roanoke, VA 24016, USA
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Sarah Taylor
- Center for Heart and Reparative Medicine, Fralin Biomedical Research Institute, Roanoke, VA 24016, USA
| | - James W. Smyth
- Center for Heart and Reparative Medicine, Fralin Biomedical Research Institute, Roanoke, VA 24016, USA
- Department of Biological Sciences, College of Science, Virginia Polytechnic State Institute and State University, Blacksburg, VA 24061, USA
- Department of Basic Science Education, Virginia Tech Carilion School of Medicine, Roanoke, VA 24016, USA
| | - John C. Chappell
- Center for Heart and Reparative Medicine, Fralin Biomedical Research Institute, Roanoke, VA 24016, USA
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic State Institute and State University, Blacksburg, VA 24061, USA
- Department of Basic Science Education, Virginia Tech Carilion School of Medicine, Roanoke, VA 24016, USA
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Špiranec K, Chen W, Werner F, Nikolaev VO, Naruke T, Koch F, Werner A, Eder-Negrin P, Diéguez-Hurtado R, Adams RH, Baba HA, Schmidt H, Schuh K, Skryabin BV, Movahedi K, Schweda F, Kuhn M. Endothelial C-Type Natriuretic Peptide Acts on Pericytes to Regulate Microcirculatory Flow and Blood Pressure. Circulation 2019; 138:494-508. [PMID: 29626067 DOI: 10.1161/circulationaha.117.033383] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Peripheral vascular resistance has a major impact on arterial blood pressure levels. Endothelial C-type natriuretic peptide (CNP) participates in the local regulation of vascular tone, but the target cells remain controversial. The cGMP-producing guanylyl cyclase-B (GC-B) receptor for CNP is expressed in vascular smooth muscle cells (SMCs). However, whereas endothelial cell-specific CNP knockout mice are hypertensive, mice with deletion of GC-B in vascular SMCs have unaltered blood pressure. METHODS We analyzed whether the vasodilating response to CNP changes along the vascular tree, ie, whether the GC-B receptor is expressed in microvascular types of cells. Mice with a floxed GC-B ( Npr2) gene were interbred with Tie2-Cre or PDGF-Rβ-Cre ERT2 lines to develop mice lacking GC-B in endothelial cells or in precapillary arteriolar SMCs and capillary pericytes. Intravital microscopy, invasive and noninvasive hemodynamics, fluorescence energy transfer studies of pericyte cAMP levels in situ, and renal physiology were combined to dissect whether and how CNP/GC-B/cGMP signaling modulates microcirculatory tone and blood pressure. RESULTS Intravital microscopy studies revealed that the vasodilatatory effect of CNP increases toward small-diameter arterioles and capillaries. CNP consistently did not prevent endothelin-1-induced acute constrictions of proximal arterioles, but fully reversed endothelin effects in precapillary arterioles and capillaries. Here, the GC-B receptor is expressed both in endothelial and mural cells, ie, in pericytes. It is notable that the vasodilatatory effects of CNP were preserved in mice with endothelial GC-B deletion, but abolished in mice lacking GC-B in microcirculatory SMCs and pericytes. CNP, via GC-B/cGMP signaling, modulates 2 signaling cascades in pericytes: it activates cGMP-dependent protein kinase I to phosphorylate downstream targets such as the cytoskeleton-associated vasodilator-activated phosphoprotein, and it inhibits phosphodiesterase 3A, thereby enhancing pericyte cAMP levels. These pathways ultimately prevent endothelin-induced increases of pericyte calcium levels and pericyte contraction. Mice with deletion of GC-B in microcirculatory SMCs and pericytes have elevated peripheral resistance and chronic arterial hypertension without a change in renal function. CONCLUSIONS Our studies indicate that endothelial CNP regulates distal arteriolar and capillary blood flow. CNP-induced GC-B/cGMP signaling in microvascular SMCs and pericytes is essential for the maintenance of normal microvascular resistance and blood pressure.
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Affiliation(s)
- Katarina Špiranec
- Institute of Physiology, University of Würzburg and Comprehensive Heart Failure Center, University Hospital Würzburg, Germany (K. Špiranec, W.C., S.C., F.W., T.N., F.K., P.E.-N., K. Schuh, M.K.)
| | - Wen Chen
- Institute of Physiology, University of Würzburg and Comprehensive Heart Failure Center, University Hospital Würzburg, Germany (K. Špiranec, W.C., S.C., F.W., T.N., F.K., P.E.-N., K. Schuh, M.K.)
| | - Franziska Werner
- Institute of Physiology, University of Würzburg and Comprehensive Heart Failure Center, University Hospital Würzburg, Germany (K. Špiranec, W.C., S.C., F.W., T.N., F.K., P.E.-N., K. Schuh, M.K.)
| | - Viacheslav O Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Germany (V.O.N.)
| | - Takashi Naruke
- Institute of Physiology, University of Würzburg and Comprehensive Heart Failure Center, University Hospital Würzburg, Germany (K. Špiranec, W.C., S.C., F.W., T.N., F.K., P.E.-N., K. Schuh, M.K.)
| | - Franziska Koch
- Institute of Physiology, University of Würzburg and Comprehensive Heart Failure Center, University Hospital Würzburg, Germany (K. Špiranec, W.C., S.C., F.W., T.N., F.K., P.E.-N., K. Schuh, M.K.)
| | - Andrea Werner
- Institute of Physiology, University of Regensburg, Germany (A.W., F.S.)
| | - Petra Eder-Negrin
- Institute of Physiology, University of Würzburg and Comprehensive Heart Failure Center, University Hospital Würzburg, Germany (K. Špiranec, W.C., S.C., F.W., T.N., F.K., P.E.-N., K. Schuh, M.K.)
| | - Rodrigo Diéguez-Hurtado
- Max-Planck-Institute for Molecular Biomedicine, Department of Tissue Morphogenesis (R.D.-H., R.H.A.)
| | - Ralf H Adams
- Max-Planck-Institute for Molecular Biomedicine, Department of Tissue Morphogenesis (R.D.-H., R.H.A.)
| | - Hideo A Baba
- Faculty of Medicine, University of Münster, Germany. Institute of Pathology, University Hospital Essen, University Duisburg-Essen, Germany (H.A.B.)
| | - Hannes Schmidt
- Interfaculty Institute of Biochemistry, University of Tübingen, Germany (H.S.)
| | - Kai Schuh
- Institute of Physiology, University of Würzburg and Comprehensive Heart Failure Center, University Hospital Würzburg, Germany (K. Špiranec, W.C., S.C., F.W., T.N., F.K., P.E.-N., K. Schuh, M.K.)
| | - Boris V Skryabin
- Core Facility Transgenic Animal and genetic engineering Models (B.V.S.)
| | - Kiavash Movahedi
- Myeloid Cell Immunology Lab, Vesalius Research Center, Center for Inflammation Research, and Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium (K.M.)
| | - Frank Schweda
- Institute of Physiology, University of Regensburg, Germany (A.W., F.S.)
| | - Michaela Kuhn
- Institute of Physiology, University of Würzburg and Comprehensive Heart Failure Center, University Hospital Würzburg, Germany (K. Špiranec, W.C., S.C., F.W., T.N., F.K., P.E.-N., K. Schuh, M.K.)
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Shaligram SS, Winkler E, Cooke D, Su H. Risk factors for hemorrhage of brain arteriovenous malformation. CNS Neurosci Ther 2019; 25:1085-1095. [PMID: 31359618 PMCID: PMC6776739 DOI: 10.1111/cns.13200] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 07/09/2019] [Accepted: 07/11/2019] [Indexed: 12/16/2022] Open
Abstract
Patients with brain arteriovenous malformation (bAVM) are at risk of intracranial hemorrhage (ICH). Overall, bAVM accounts for 25% of hemorrhagic strokes in adults <50 years of age. The treatment of unruptured bAVMs has become controversial, because the natural history of these patients may be less morbid than invasive therapies. Available treatments include observation, surgical resection, endovascular embolization, stereotactic radiosurgery, or combination thereof. Knowing the risk factors for bAVM hemorrhage is crucial for selecting appropriate therapeutic strategies. In this review, we discussed several biological risk factors, which may contribute to bAVM hemorrhage.
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Affiliation(s)
- Sonali S Shaligram
- Center for Cerebrovascular Research, Department of Anesthesia and Perioperative care, University of California, San Francisco, California
| | - Ethan Winkler
- Department of Neurological Surgery, University of California, San Francisco, California
| | - Daniel Cooke
- Department of Radiology, University of California, San Francisco, California
| | - Hua Su
- Center for Cerebrovascular Research, Department of Anesthesia and Perioperative care, University of California, San Francisco, California
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36
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Li B, Esipova TV, Sencan I, Kılıç K, Fu B, Desjardins M, Moeini M, Kura S, Yaseen MA, Lesage F, Østergaard L, Devor A, Boas DA, Vinogradov SA, Sakadžić S. More homogeneous capillary flow and oxygenation in deeper cortical layers correlate with increased oxygen extraction. eLife 2019; 8:42299. [PMID: 31305237 PMCID: PMC6636997 DOI: 10.7554/elife.42299] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 07/01/2019] [Indexed: 01/01/2023] Open
Abstract
Our understanding of how capillary blood flow and oxygen distribute across cortical layers to meet the local metabolic demand is incomplete. We addressed this question by using two-photon imaging of resting-state microvascular oxygen partial pressure (PO2) and flow in the whisker barrel cortex in awake mice. Our measurements in layers I-V show that the capillary red-blood-cell flux and oxygenation heterogeneity, and the intracapillary resistance to oxygen delivery, all decrease with depth, reaching a minimum around layer IV, while the depth-dependent oxygen extraction fraction is increased in layer IV, where oxygen demand is presumably the highest. Our findings suggest that more homogeneous distribution of the physiological observables relevant to oxygen transport to tissue is an important part of the microvascular network adaptation to local brain metabolism. These results will inform the biophysical models of layer-specific cerebral oxygen delivery and consumption and improve our understanding of the diseases that affect cerebral microcirculation.
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Affiliation(s)
- Baoqiang Li
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
| | - Tatiana V Esipova
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, United States.,Department of Chemistry, University of Pennsylvania, Philadelphia, United States
| | - Ikbal Sencan
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
| | - Kıvılcım Kılıç
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Buyin Fu
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
| | - Michele Desjardins
- Department of Radiology, University of California, San Diego, La Jolla, United States
| | - Mohammad Moeini
- Institute of Biomedical Engineering, École Polytechnique de Montréal, Montréal, Canada.,Research Centre, Montreal Heart Institute, Montréal, Canada
| | - Sreekanth Kura
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
| | - Mohammad A Yaseen
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
| | - Frederic Lesage
- Institute of Biomedical Engineering, École Polytechnique de Montréal, Montréal, Canada.,Research Centre, Montreal Heart Institute, Montréal, Canada
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Anna Devor
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States.,Department of Neurosciences, University of California, San Diego, La Jolla, United States.,Department of Radiology, University of California, San Diego, La Jolla, United States
| | - David A Boas
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States.,Department of Biomedical Engineering, Boston University, Boston, United States
| | - Sergei A Vinogradov
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, United States.,Department of Chemistry, University of Pennsylvania, Philadelphia, United States
| | - Sava Sakadžić
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
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37
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Nortley R, Korte N, Izquierdo P, Hirunpattarasilp C, Mishra A, Jaunmuktane Z, Kyrargyri V, Pfeiffer T, Khennouf L, Madry C, Gong H, Richard-Loendt A, Huang W, Saito T, Saido TC, Brandner S, Sethi H, Attwell D. Amyloid β oligomers constrict human capillaries in Alzheimer's disease via signaling to pericytes. Science 2019; 365:science.aav9518. [PMID: 31221773 DOI: 10.1126/science.aav9518] [Citation(s) in RCA: 385] [Impact Index Per Article: 77.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 04/10/2019] [Accepted: 06/04/2019] [Indexed: 12/17/2022]
Abstract
Cerebral blood flow is reduced early in the onset of Alzheimer's disease (AD). Because most of the vascular resistance within the brain is in capillaries, this could reflect dysfunction of contractile pericytes on capillary walls. We used live and rapidly fixed biopsied human tissue to establish disease relevance, and rodent experiments to define mechanism. We found that in humans with cognitive decline, amyloid β (Aβ) constricts brain capillaries at pericyte locations. This was caused by Aβ generating reactive oxygen species, which evoked the release of endothelin-1 (ET) that activated pericyte ETA receptors. Capillary, but not arteriole, constriction also occurred in vivo in a mouse model of AD. Thus, inhibiting the capillary constriction caused by Aβ could potentially reduce energy lack and neurodegeneration in AD.
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Affiliation(s)
- Ross Nortley
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Nils Korte
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Pablo Izquierdo
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Chanawee Hirunpattarasilp
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Anusha Mishra
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Zane Jaunmuktane
- Division of Neuropathology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK.,Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Vasiliki Kyrargyri
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Thomas Pfeiffer
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Lila Khennouf
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Christian Madry
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Hui Gong
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Angela Richard-Loendt
- Division of Neuropathology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Wenhui Huang
- Molecular Physiology, CIPMM, University of Saarland, D-66421 Homburg, Germany
| | - Takashi Saito
- Laboratory for Proteolytic Neuroscience, RIKEN Centre for Brain Science, Wako, Saitama 351-0198, Japan
| | - Takaomi C Saido
- Laboratory for Proteolytic Neuroscience, RIKEN Centre for Brain Science, Wako, Saitama 351-0198, Japan
| | - Sebastian Brandner
- Division of Neuropathology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK.,Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Huma Sethi
- Division of Neurosurgery, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK.
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38
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Isasi E, Korte N, Abudara V, Attwell D, Olivera-Bravo S. Glutaric Acid Affects Pericyte Contractility and Migration: Possible Implications for GA-I Pathogenesis. Mol Neurobiol 2019; 56:7694-7707. [DOI: 10.1007/s12035-019-1620-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 04/23/2019] [Indexed: 01/23/2023]
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39
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Zhao H, Chappell JC. Microvascular bioengineering: a focus on pericytes. J Biol Eng 2019; 13:26. [PMID: 30984287 PMCID: PMC6444752 DOI: 10.1186/s13036-019-0158-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 03/15/2019] [Indexed: 12/26/2022] Open
Abstract
Capillaries within the microcirculation are essential for oxygen delivery and nutrient/waste exchange, among other critical functions. Microvascular bioengineering approaches have sought to recapitulate many key features of these capillary networks, with an increasing appreciation for the necessity of incorporating vascular pericytes. Here, we briefly review established and more recent insights into important aspects of pericyte identification and function within the microvasculature. We then consider the importance of including vascular pericytes in various bioengineered microvessel platforms including 3D culturing and microfluidic systems. We also discuss how vascular pericytes are a vital component in the construction of computational models that simulate microcirculation phenomena including angiogenesis, microvascular biomechanics, and kinetics of exchange across the vessel wall. In reviewing these topics, we highlight the notion that incorporating pericytes into microvascular bioengineering applications will increase their utility and accelerate the translation of basic discoveries to clinical solutions for vascular-related pathologies.
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Affiliation(s)
- Huaning Zhao
- Center for Heart and Reparative Medicine, Fralin Biomedical Research Institute, 2 Riverside Circle, Roanoke, VA 24016 USA.,Department of Biomedical Engineering and Mechanics, Virginia Polytechnic State Institute and State University, Blacksburg, VA 24061 USA
| | - John C Chappell
- Center for Heart and Reparative Medicine, Fralin Biomedical Research Institute, 2 Riverside Circle, Roanoke, VA 24016 USA.,Department of Biomedical Engineering and Mechanics, Virginia Polytechnic State Institute and State University, Blacksburg, VA 24061 USA.,3Department of Basic Science Education, Virginia Tech Carilion School of Medicine, Roanoke, VA 24016 USA
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40
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Pétrault M, Casolla B, Ouk T, Cordonnier C, Bérézowski V. Cerebral microbleeds: Beyond the macroscope. Int J Stroke 2019; 14:468-475. [DOI: 10.1177/1747493019830594] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
While being increasingly recognized in clinical routine, brain microbleeds remain a puzzling finding for physicians. These small dot-like lesions are thought to be old perivascular collections of hemosiderin deposits. They can be found in different neurological settings such as cerebrovascular or neurodegenerative diseases. While their microscopic size would suggest considering these lesions as anecdotal, they are now regarded as biomarkers of severity of an underlying cerebrovascular disease. Their natural history and the interactions with surrounding brain cells remain unknown. However, their presence may impact therapeutic decisions. Deciphering the biological mechanisms leading to, or following microbleeds would enable us to address a key question: do microbleeds arise and impact the surrounding parenchyma like a miniature version of intracerebral hemorrhages or do they represent a different kind of injury? We hereby discuss, based on both clinical and experimental literature, the gap between the definition of microbleeds coming from neuroimaging and the pathophysiological hypotheses raised from histopathological and experimental data. Our analysis supports the need for a convergent effort from clinicians and basic scientists to go beyond the current “macro” view and disclose the cellular and molecular insights of these cerebral hemorrhagic microlesions.
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Affiliation(s)
- Maud Pétrault
- Department of Medical Pharmacology, Univ Lille, Inserm U1171-Degenerative and Vascular Cognitive Disorders, CHU Lille, Lille, France
| | - Barbara Casolla
- Department of Neurology, Univ Lille, Inserm U1171-Degenerative and Vascular Cognitive Disorders, CHU Lille, Lille, France
| | - Thavarak Ouk
- Department of Medical Pharmacology, Univ Lille, Inserm U1171-Degenerative and Vascular Cognitive Disorders, CHU Lille, Lille, France
| | - Charlotte Cordonnier
- Department of Neurology, Univ Lille, Inserm U1171-Degenerative and Vascular Cognitive Disorders, CHU Lille, Lille, France
| | - Vincent Bérézowski
- Department of Medical Pharmacology, Univ Lille, Inserm U1171-Degenerative and Vascular Cognitive Disorders, CHU Lille, Lille, France
- Univ Artois, Lens, France
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41
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Romero-Leguizamón CR, Elnagar MR, Kristiansen U, Kohlmeier KA. Increasing cellular lifespan with a flow system in organotypic culture of the Laterodorsal Tegmentum (LDT). Sci Rep 2019; 9:1486. [PMID: 30728375 PMCID: PMC6365664 DOI: 10.1038/s41598-018-37606-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 12/10/2018] [Indexed: 12/31/2022] Open
Abstract
Organotypic brain culture is an experimental tool widely used in neuroscience studies. One major drawback of this technique is reduced neuronal survival across time, which is likely exacerbated by the loss of blood flow. We have designed a novel, tube flow system, which is easily incorporated into the commonly-used, standard semi-permeable membrane culture methodology which has significantly enhanced neuronal survival in a brain stem nucleus involved in control of motivated and arousal states: the laterodorsal tegmental nucleus (LDT). Our automated system provides nutrients and removes waste in a comparatively aseptic environment, while preserving temperature, and oxygen levels. Using immunohistochemistry and electrophysiology, our system was found superior to standard techniques in preserving tissue quality and survival of LDT cells for up to 2 weeks. In summary, we provide evidence for the first time that the LDT can be preserved in organotypic slice culture, and further, our technical improvements of adding a flow system, which likely enhanced perfusion to the slice, were associated with enhanced neuronal survival. Our perfusion system is expected to facilitate organotypic experiments focused on chronic stimulations and multielectrode recordings in the LDT, as well as enhance neuronal survival in slice cultures originating from other brain regions.
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Affiliation(s)
- César R Romero-Leguizamón
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Mohamed R Elnagar
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt
| | - Uffe Kristiansen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Kristi A Kohlmeier
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2100, Denmark.
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42
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Lee LL, Chintalgattu V. Pericytes in the Heart. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1122:187-210. [PMID: 30937870 DOI: 10.1007/978-3-030-11093-2_11] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Mural cells known as pericytes envelop the endothelial layer of microvessels throughout the body and have been described to have tissue-specific functions. Cardiac pericytes are abundantly found in the heart, but they are relatively understudied. Currently, their importance is emerging in cardiovascular homeostasis and dysfunction due to their pleiotropism. They are known to play key roles in vascular tone and vascular integrity as well as angiogenesis. However, their dysfunctional presence and/or absence is critical in the mechanisms that lead to cardiac pathologies such as myocardial infarction, fibrosis, and thrombosis. Moreover, they are targeted as a therapeutic potential due to their mesenchymal properties that could allow them to repair and regenerate a damaged heart. They are also sought after as a cell-based therapy based on their healing potential in preclinical studies of animal models of myocardial infarction. Therefore, recognizing the importance of cardiac pericytes and understanding their biology will lead to new therapeutic concepts.
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Affiliation(s)
- Linda L Lee
- Department of CardioMetabolic Disorders, Amgen Research and Discovery, Amgen Inc., South San Francisco, CA, USA
| | - Vishnu Chintalgattu
- Department of CardioMetabolic Disorders, Amgen Research and Discovery, Amgen Inc., South San Francisco, CA, USA.
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43
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Ting JT, Lee BR, Chong P, Soler-Llavina G, Cobbs C, Koch C, Zeng H, Lein E. Preparation of Acute Brain Slices Using an Optimized N-Methyl-D-glucamine Protective Recovery Method. J Vis Exp 2018. [PMID: 29553547 DOI: 10.3791/53825] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
This protocol is a practical guide to the N-methyl-D-glucamine (NMDG) protective recovery method of brain slice preparation. Numerous recent studies have validated the utility of this method for enhancing neuronal preservation and overall brain slice viability. The implementation of this technique by early adopters has facilitated detailed investigations into brain function using diverse experimental applications and spanning a wide range of animal ages, brain regions, and cell types. Steps are outlined for carrying out the protective recovery brain slice technique using an optimized NMDG artificial cerebrospinal fluid (aCSF) media formulation and enhanced procedure to reliably obtain healthy brain slices for patch clamp electrophysiology. With this updated approach, a substantial improvement is observed in the speed and reliability of gigaohm seal formation during targeted patch clamp recording experiments while maintaining excellent neuronal preservation, thereby facilitating challenging experimental applications. Representative results are provided from multi-neuron patch clamp recording experiments to assay synaptic connectivity in neocortical brain slices prepared from young adult transgenic mice and mature adult human neurosurgical specimens. Furthermore, the optimized NMDG protective recovery method of brain slicing is compatible with both juvenile and adult animals, thus resolving a limitation of the original methodology. In summary, a single media formulation and brain slicing procedure can be implemented across various species and ages to achieve excellent viability and tissue preservation.
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Affiliation(s)
| | - Brian R Lee
- Cell Types Program, Allen Institute for Brain Science
| | - Peter Chong
- Cell Types Program, Allen Institute for Brain Science
| | | | - Charles Cobbs
- The Ben and Catherine Ivy Center for Advanced Brain Tumor Treatment, Swedish Neuroscience Institute
| | - Christof Koch
- Cell Types Program, Allen Institute for Brain Science
| | - Hongkui Zeng
- Cell Types Program, Allen Institute for Brain Science
| | - Ed Lein
- Cell Types Program, Allen Institute for Brain Science
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44
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Rustenhoven J, Smyth LC, Jansson D, Schweder P, Aalderink M, Scotter EL, Mee EW, Faull RLM, Park TIH, Dragunow M. Modelling physiological and pathological conditions to study pericyte biology in brain function and dysfunction. BMC Neurosci 2018; 19:6. [PMID: 29471788 PMCID: PMC5824614 DOI: 10.1186/s12868-018-0405-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 02/10/2018] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Brain pericytes ensheathe the endothelium and contribute to formation and maintenance of the blood-brain-barrier. Additionally, pericytes are involved in several aspects of the CNS immune response including scarring, adhesion molecule expression, chemokine secretion, and phagocytosis. In vitro cultures are routinely used to investigate these functions of brain pericytes, however, these are highly plastic cells and can display differing phenotypes and functional responses depending on their culture conditions. Here we sought to investigate how two commonly used culture media, high serum containing DMEM/F12 and low serum containing Pericyte Medium (ScienCell), altered the phenotype of human brain pericytes and neuroinflammatory responses. METHODS Pericytes were isolated from adult human brain biopsy tissue and cultured in DMEM/F12 (D-pericytes) or Pericyte Medium (P-pericytes). Immunocytochemistry, qRT-PCR, and EdU incorporation were used to determine how this altered their basal phenotype, including the expression of pericyte markers, proliferation, and cell morphology. To determine whether culture media altered the inflammatory response in human brain pericytes, immunocytochemistry, qRT-PCR, cytometric bead arrays, and flow cytometry were used to investigate transcription factor induction, chemokine secretion, adhesion molecule expression, migration, phagocytosis, and response to inflammatory-related growth factors. RESULTS P-pericytes displayed elevated proliferation and a distinct bipolar morphology compared to D-pericytes. Additionally, P-pericytes displayed lower expression of pericyte-associated markers NG2, PDGFRβ, and fibronectin, with notably lower αSMA, CD146, P4H and desmin, and higher Col-IV expression. Nuclear NF-kB translocation in response to IL-1β stimulation was observed in both cultures, however, P-pericytes displayed elevated expression of the transcription factor C/EBPδ, and lower expression of the adhesion molecule ICAM-1. P-pericytes displayed elevated phagocytic and migratory ability. Both cultures responded similarly to stimulation by the growth factors TGFβ1 and PDGF-BB. CONCLUSIONS Despite differences in their phenotype and magnitude of response, both P-pericytes and D-pericytes responded similarly to all examined functions, indicating that the neuroinflammatory phenotype of these cells is robust to culture conditions.
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Affiliation(s)
- Justin Rustenhoven
- Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand.,Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand
| | - Leon C Smyth
- Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand.,Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand
| | - Deidre Jansson
- Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand.,Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand
| | - Patrick Schweder
- Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand.,Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand.,Auckland City Hospital, Auckland, New Zealand
| | - Miranda Aalderink
- Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand.,Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand
| | - Emma L Scotter
- Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand.,Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand
| | - Edward W Mee
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand.,Auckland City Hospital, Auckland, New Zealand
| | - Richard L M Faull
- Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand.,Department of Anatomy and Medical Imagining, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand
| | - Thomas I-H Park
- Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand.,Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand
| | - Mike Dragunow
- Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand. .,Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand. .,Department of Pharmacology and Clinical Pharmacology, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.
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45
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Cerebrovascular heterogeneity and neuronal excitability. Neurosci Lett 2018; 667:75-83. [DOI: 10.1016/j.neulet.2017.01.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 01/04/2017] [Accepted: 01/06/2017] [Indexed: 01/01/2023]
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46
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Metabolomic analysis of low and high biofilm-forming Helicobacter pylori strains. Sci Rep 2018; 8:1409. [PMID: 29362474 PMCID: PMC5780479 DOI: 10.1038/s41598-018-19697-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 01/08/2018] [Indexed: 12/16/2022] Open
Abstract
The biofilm-forming-capability of Helicobacter pylori has been suggested to be among factors influencing treatment outcome. However, H. pylori exhibit strain-to-strain differences in biofilm-forming-capability. Metabolomics enables the inference of spatial and temporal changes of metabolic activities during biofilm formation. Our study seeks to examine the differences in metabolome of low and high biofilm-formers using the metabolomic approach. Eight H. pylori clinical strains with different biofilm-forming-capability were chosen for metabolomic analysis. Bacterial metabolites were extracted using Bligh and Dyer method and analyzed by Liquid Chromatography/Quadrupole Time-of-Flight mass spectrometry. The data was processed and analyzed using the MassHunter Qualitative Analysis and the Mass Profiler Professional programs. Based on global metabolomic profiles, low and high biofilm-formers presented as two distinctly different groups. Interestingly, low-biofilm-formers produced more metabolites than high-biofilm-formers. Further analysis was performed to identify metabolites that differed significantly (p-value < 0.005) between low and high biofilm-formers. These metabolites include major categories of lipids and metabolites involve in prostaglandin and folate metabolism. Our findings suggest that biofilm formation in H. pylori is complex and probably driven by the bacterium’ endogenous metabolism. Understanding the underlying metabolic differences between low and high biofilm-formers may enhance our current understanding of pathogenesis, extragastric survival and transmission of H. pylori infections.
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47
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Cudmore RH, Dougherty SE, Linden DJ. Cerebral vascular structure in the motor cortex of adult mice is stable and is not altered by voluntary exercise. J Cereb Blood Flow Metab 2017; 37:3725-3743. [PMID: 28059584 PMCID: PMC5718320 DOI: 10.1177/0271678x16682508] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 10/24/2016] [Accepted: 10/30/2016] [Indexed: 01/09/2023]
Abstract
The cerebral vasculature provides blood flow throughout the brain, and local changes in blood flow are regulated to match the metabolic demands of the active brain regions. This neurovascular coupling is mediated by real-time changes in vessel diameter and depends on the underlying vascular network structure. Neurovascular structure is configured during development by genetic and activity-dependent factors. In adulthood, it can be altered by experiences such as prolonged hypoxia, sensory deprivation and seizure. Here, we have sought to determine whether exercise could alter cerebral vascular structure in the adult mouse. We performed repeated in vivo two-photon imaging in the motor cortex of adult transgenic mice expressing membrane-anchored green fluorescent protein in endothelial cells (tyrosine endothelial kinase 2 receptor (Tie2)-Cre:mTmG). This strategy allows for high-resolution imaging of the vessel walls throughout the lifespan. Vascular structure, as measured by capillary branch point number and position, segment diameter and length remained stable over a time scale of months as did pericyte number and position. Furthermore, we compared the vascular structure before, during, and after periods of voluntary wheel running and found no alterations in these same parameters. In both running and control mice, we observed a low rate of capillary segment subtraction. Interestingly, these rare subtraction events preferentially remove short vascular loops.
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Affiliation(s)
- Robert H Cudmore
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sarah E Dougherty
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - David J Linden
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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48
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O'Farrell FM, Mastitskaya S, Hammond-Haley M, Freitas F, Wah WR, Attwell D. Capillary pericytes mediate coronary no-reflow after myocardial ischaemia. eLife 2017; 6:29280. [PMID: 29120327 PMCID: PMC5705208 DOI: 10.7554/elife.29280] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 11/08/2017] [Indexed: 12/22/2022] Open
Abstract
After cardiac ischaemia, a prolonged decrease of coronary microvascular perfusion often occurs even after flow is restored in an upstream artery. This 'no-reflow' phenomenon worsens patient prognosis. In the brain, after stroke, a similar post-ischaemic 'no-reflow' has been attributed to capillary constriction by contractile pericytes. We now show that occlusion of a rat coronary artery, followed by reperfusion, blocks 40% of cardiac capillaries and halves perfused blood volume within the affected region. Capillary blockages colocalised strongly with pericytes, where capillary diameter was reduced by 37%. The pericyte relaxant adenosine increased capillary diameter by 21% at pericyte somata, decreased capillary block by 25% and increased perfusion volume by 57%. Thus, cardiac pericytes constrict coronary capillaries and reduce microvascular blood flow after ischaemia, despite re-opening of the culprit artery. Cardiac pericytes are therefore a novel therapeutic target in ischaemic heart disease. Heart attacks occur when one of the arteries supplying blood to the heart muscle becomes blocked, usually by a blood clot. Doctors unblock the artery and insert an expanding metal cage called a stent to keep it unblocked. This restores blood flow through the artery. Unfortunately, blood flow often does not return to smaller downstream blood vessels called capillaries. This can lead to further damage to the heart. Scientists have not been able to find a way to reliably open up those capillaries after a heart attack because it is not clear exactly what is keeping them closed. Muscle-like cells called pericytes, which wrap around the capillaries, are one possible culprit for the blockages. Pericytes narrow capillaries in the brain after stroke in animal experiments. These cells are also present on heart capillaries, but scientists do not know much about them. Now, O’Farrell, Mastitskaya, Hammond-Haley et al. show that pericytes are partly responsible for limiting blood flow in capillaries after a heart attack in rats. In the experiments, blood flow through an artery feeding the hearts of anaesthetized rats was restricted, simulating a heart attack. After the blood flow was later restored, 40% of the animal’s capillaries remained blocked. Many blockages occurred near pericytes that had narrowed the capillary preventing blood flow. Treating the rats with a drug called adenosine, which relaxes the pericytes, reduced capillary blockages and increased blood flow in the heart. Although adenosine could help to restore blood flow in the capillaries after a heart attack, it may also relax muscles around arteries and lower blood pressure, and so it may not be an ideal treatment. More studies are needed to determine whether drugs that target only the pericytes could complement existing heart attack treatments that unblock the arteries. If these studies are successful, pericyte-targeting drugs might prevent serious complications after a heart attack, including heart failure, heart rhythm abnormalities and future heart attacks.
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Affiliation(s)
- Fergus M O'Farrell
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Svetlana Mastitskaya
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Matthew Hammond-Haley
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Felipe Freitas
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Wen Rui Wah
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
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49
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Poplawsky AJ, Fukuda M, Kang BM, Kim JH, Suh M, Kim SG. Dominance of layer-specific microvessel dilation in contrast-enhanced high-resolution fMRI: Comparison between hemodynamic spread and vascular architecture with CLARITY. Neuroimage 2017; 197:657-667. [PMID: 28822749 DOI: 10.1016/j.neuroimage.2017.08.046] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 08/04/2017] [Accepted: 08/15/2017] [Indexed: 10/19/2022] Open
Abstract
Contrast-enhanced cerebral blood volume-weighted (CBVw) fMRI response peaks are specific to the layer of evoked synaptic activity (Poplawsky et al., 2015), but the spatial resolution limit of CBVw fMRI is unknown. In this study, we measured the laminar spread of the CBVw fMRI evoked response in the external plexiform layer (EPL, 265 ± 65 μm anatomical thickness, mean ± SD, n = 30 locations from 5 rats) of the rat olfactory bulb during electrical stimulation of the lateral olfactory tract and examined its potential vascular source. First, we obtained the evoked CBVw fMRI responses with a 55 × 55 μm2 in-plane resolution and a 500-μm thickness at 9.4 T, and found that the fMRI signal peaked predominantly in the inner half of EPL (136 ± 54 μm anatomical thickness). The mean full-width at half-maximum of these fMRI peaks was 347 ± 102 μm and the functional spread was approximately 100 or 200 μm when the effects of the laminar thicknesses of EPL or inner EPL were removed, respectively. Second, we visualized the vascular architecture of EPL from a different rat using a Clear Lipid-exchanged Anatomically Rigid Imaging/immunostaining-compatible Tissue hYdrogel (CLARITY)-based tissue preparation method and confocal microscopy. Microvascular segments with an outer diameter of <11 μm accounted for 64.3% of the total vascular volume within EPL and had a mean segment length of 55 ± 40 μm (n = 472). Additionally, vessels that crossed the EPL border had a mean segment length outside of EPL equal to 73 ± 61 μm (n = 28), which is comparable to half of the functional spread (50-100 μm). Therefore, we conclude that dilation of these microvessels, including capillaries, likely dominate the CBVw fMRI response and that the biological limit of the fMRI spatial resolution is approximately the average length of 1-2 microvessel segments, which may be sufficient for examining sublaminar circuits.
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Affiliation(s)
| | - Mitsuhiro Fukuda
- Neuroimaging Laboratory, Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Bok-Man Kang
- Center for Neuroscience Imaging Research, Institute of Basic Science, Suwon, 440-746, Republic of Korea; Department of Biomedical Engineering, Sungkyunkwan University, Suwon, 440-746, Republic of Korea
| | - Jae Hwan Kim
- Center for Neuroscience Imaging Research, Institute of Basic Science, Suwon, 440-746, Republic of Korea
| | - Minah Suh
- Center for Neuroscience Imaging Research, Institute of Basic Science, Suwon, 440-746, Republic of Korea; Department of Biomedical Engineering, Sungkyunkwan University, Suwon, 440-746, Republic of Korea
| | - Seong-Gi Kim
- Center for Neuroscience Imaging Research, Institute of Basic Science, Suwon, 440-746, Republic of Korea; Department of Biomedical Engineering, Sungkyunkwan University, Suwon, 440-746, Republic of Korea.
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50
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Neuhaus AA, Couch Y, Sutherland BA, Buchan AM. Novel method to study pericyte contractility and responses to ischaemia in vitro using electrical impedance. J Cereb Blood Flow Metab 2017; 37:2013-2024. [PMID: 27418036 PMCID: PMC5464697 DOI: 10.1177/0271678x16659495] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Pericytes are contractile vascular mural cells overlying capillary endothelium, and they have been implicated in a variety of functions including regulation of cerebral blood flow. Recent work has suggested that both in vivo and ex vivo, ischaemia causes pericytes to constrict and die, which has implications for microvascular reperfusion. Assessing pericyte contractility in tissue slices and in vivo is technically challenging, while in vitro techniques remain unreliable. Here, we used isolated cultures of human brain vascular pericytes to examine their contractile potential in vitro using the iCelligence electrical impedance system. Contraction was induced using the vasoactive peptide endothelin-1, and relaxation was demonstrated using adenosine and sodium nitroprusside. Endothelin-1 treatment also resulted in increased proliferation, which we were able to monitor in the same cell population from which we recorded contractile responses. Finally, the observation of pericyte contraction in stroke was reproduced using chemical ischaemia, which caused a profound and irreversible contraction clearly preceding cell death. These data demonstrate that isolated pericytes retain a contractile phenotype in vitro, and that it is possible to quantify this contraction using real-time electrical impedance recordings, providing a significant new platform for assessing the effects of vasoactive and vasculoprotective compounds on pericyte contractility.
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Affiliation(s)
- Ain A Neuhaus
- 1 Acute Stroke Programme, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Yvonne Couch
- 1 Acute Stroke Programme, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Brad A Sutherland
- 1 Acute Stroke Programme, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.,4 School of Medicine, Faculty of Health, University of Tasmania, Hobart, Australia
| | - Alastair M Buchan
- 1 Acute Stroke Programme, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.,2 Medical Sciences Division, University of Oxford, Oxford, UK.,3 Acute Vascular Imaging Centre, University of Oxford, Oxford University Hospitals, Oxford, UK
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