201
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Lin A, Peiris NJ, Dhaliwal H, Hakim M, Li W, Ganesh S, Ramaswamy Y, Patel S, Misra A. Mural Cells: Potential Therapeutic Targets to Bridge Cardiovascular Disease and Neurodegeneration. Cells 2021; 10:cells10030593. [PMID: 33800271 PMCID: PMC7999039 DOI: 10.3390/cells10030593] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 03/01/2021] [Accepted: 03/04/2021] [Indexed: 02/06/2023] Open
Abstract
Mural cells collectively refer to the smooth muscle cells and pericytes of the vasculature. This heterogenous population of cells play a crucial role in the regulation of blood pressure, distribution, and the structural integrity of the vascular wall. As such, dysfunction of mural cells can lead to the pathogenesis and progression of a number of diseases pertaining to the vascular system. Cardiovascular diseases, particularly atherosclerosis, are perhaps the most well-described mural cell-centric case. For instance, atherosclerotic plaques are most often described as being composed of a proliferative smooth muscle cap accompanied by a necrotic core. More recently, the role of dysfunctional mural cells in neurodegenerative diseases, such as Alzheimer’s and Parkinson’s disease, is being recognized. In this review, we begin with an exploration of the mechanisms underlying atherosclerosis and neurodegenerative diseases, such as mural cell plasticity. Next, we highlight a selection of signaling pathways (PDGF, Notch and inflammatory signaling) that are conserved across both diseases. We propose that conserved mural cell signaling mechanisms can be exploited for the identification or development of dual-pronged therapeutics that impart both cardio- and neuroprotective qualities.
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MESH Headings
- Alzheimer Disease/drug therapy
- Alzheimer Disease/genetics
- Alzheimer Disease/metabolism
- Alzheimer Disease/pathology
- Animals
- Atherosclerosis/drug therapy
- Atherosclerosis/genetics
- Atherosclerosis/metabolism
- Atherosclerosis/pathology
- Cardiotonic Agents/pharmacology
- Disease Models, Animal
- Gene Expression Regulation
- Humans
- Mice
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Myocytes, Smooth Muscle/pathology
- Neuroprotective Agents/pharmacology
- Parkinson Disease/drug therapy
- Parkinson Disease/genetics
- Parkinson Disease/metabolism
- Parkinson Disease/pathology
- Pericytes/drug effects
- Pericytes/metabolism
- Pericytes/pathology
- Plaque, Atherosclerotic/drug therapy
- Plaque, Atherosclerotic/genetics
- Plaque, Atherosclerotic/metabolism
- Plaque, Atherosclerotic/pathology
- Platelet-Derived Growth Factor/genetics
- Platelet-Derived Growth Factor/metabolism
- Receptors, Notch/genetics
- Receptors, Notch/metabolism
- Signal Transduction
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Affiliation(s)
- Alexander Lin
- Heart Research Institute, Sydney, NSW 2042, Australia; (A.L.); (N.J.P.); (H.D.); (M.H.); (W.L.); (S.P.)
- School of Biomedical Engineering, Faculty of Engineering, The University of Sydney, Sydney, NSW 2006, Australia;
| | - Niridu Jude Peiris
- Heart Research Institute, Sydney, NSW 2042, Australia; (A.L.); (N.J.P.); (H.D.); (M.H.); (W.L.); (S.P.)
- Sydney Medical School, The University of Sydney, Sydney, NSW 2006, Australia
| | - Harkirat Dhaliwal
- Heart Research Institute, Sydney, NSW 2042, Australia; (A.L.); (N.J.P.); (H.D.); (M.H.); (W.L.); (S.P.)
- Sydney Medical School, The University of Sydney, Sydney, NSW 2006, Australia
| | - Maria Hakim
- Heart Research Institute, Sydney, NSW 2042, Australia; (A.L.); (N.J.P.); (H.D.); (M.H.); (W.L.); (S.P.)
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Weizhen Li
- Heart Research Institute, Sydney, NSW 2042, Australia; (A.L.); (N.J.P.); (H.D.); (M.H.); (W.L.); (S.P.)
- School of Biomedical Engineering, Faculty of Engineering, The University of Sydney, Sydney, NSW 2006, Australia;
| | - Subramaniam Ganesh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India;
- The Mehta Family Centre for Engineering in Medicine, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India
| | - Yogambha Ramaswamy
- School of Biomedical Engineering, Faculty of Engineering, The University of Sydney, Sydney, NSW 2006, Australia;
| | - Sanjay Patel
- Heart Research Institute, Sydney, NSW 2042, Australia; (A.L.); (N.J.P.); (H.D.); (M.H.); (W.L.); (S.P.)
- Sydney Medical School, The University of Sydney, Sydney, NSW 2006, Australia
- Cardiac Catheterization Laboratory, Royal Prince Alfred Hospital, Sydney, NSW 2050, Australia
| | - Ashish Misra
- Heart Research Institute, Sydney, NSW 2042, Australia; (A.L.); (N.J.P.); (H.D.); (M.H.); (W.L.); (S.P.)
- Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia
- Correspondence: ; Tel.: +61-18-0065-1373
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202
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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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203
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Thakore P, Alvarado MG, Ali S, Mughal A, Pires PW, Yamasaki E, Pritchard HA, Isakson BE, Tran CHT, Earley S. Brain endothelial cell TRPA1 channels initiate neurovascular coupling. eLife 2021; 10:63040. [PMID: 33635784 PMCID: PMC7935492 DOI: 10.7554/elife.63040] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 02/25/2021] [Indexed: 02/07/2023] Open
Abstract
Cerebral blood flow is dynamically regulated by neurovascular coupling to meet the dynamic metabolic demands of the brain. We hypothesized that TRPA1 channels in capillary endothelial cells are stimulated by neuronal activity and instigate a propagating retrograde signal that dilates upstream parenchymal arterioles to initiate functional hyperemia. We find that activation of TRPA1 in capillary beds and post-arteriole transitional segments with mural cell coverage initiates retrograde signals that dilate upstream arterioles. These signals exhibit a unique mode of biphasic propagation. Slow, short-range intercellular Ca2+ signals in the capillary network are converted to rapid electrical signals in transitional segments that propagate to and dilate upstream arterioles. We further demonstrate that TRPA1 is necessary for functional hyperemia and neurovascular coupling within the somatosensory cortex of mice in vivo. These data establish endothelial cell TRPA1 channels as neuronal activity sensors that initiate microvascular vasodilatory responses to redirect blood to regions of metabolic demand.
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Affiliation(s)
- Pratish Thakore
- Department of Pharmacology, Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States
| | - Michael G Alvarado
- Department of Pharmacology, Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States
| | - Sher Ali
- Department of Pharmacology, Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States
| | - Amreen Mughal
- Department of Pharmacology, College of Medicine, University of Vermont, Burlington, United States
| | - Paulo W Pires
- Department of Physiology, College of Medicine, University of Arizona, Tucson, United States
| | - Evan Yamasaki
- Department of Pharmacology, Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States
| | - Harry At Pritchard
- Department of Pharmacology, Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States.,Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| | - Brant E Isakson
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, United States.,Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, United States
| | - Cam Ha T Tran
- Department of Physiology & Cell Biology, Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States
| | - Scott Earley
- Department of Pharmacology, Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States
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204
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Nicoli S, Grutzendler J. Unlocking Pericyte Function in the Adult Blood Brain Barrier One Cell at a Time. Circ Res 2021; 128:511-512. [PMID: 33600230 DOI: 10.1161/circresaha.121.318799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Stefania Nicoli
- Departments of Internal Medicine, Section of Cardiology, Yale Cardiovascular Research Center (S.N.), Yale University School of Medicine, New Haven, CT.,Genetics (S.N.), Yale University School of Medicine, New Haven, CT.,Pharmacology (S.N.), Yale University School of Medicine, New Haven, CT
| | - Jaime Grutzendler
- Neurology (J.G.), Yale University School of Medicine, New Haven, CT.,Neuroscience (J.G.), Yale University School of Medicine, New Haven, CT
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205
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Duffin J, Mikulis DJ, Fisher JA. Control of Cerebral Blood Flow by Blood Gases. Front Physiol 2021; 12:640075. [PMID: 33679453 PMCID: PMC7930328 DOI: 10.3389/fphys.2021.640075] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 01/25/2021] [Indexed: 12/19/2022] Open
Abstract
Cerebrovascular reactivity can be measured as the cerebrovascular flow response to a hypercapnic challenge. The many faceted responses of cerebral blood flow to combinations of blood gas challenges are mediated by its vasculature's smooth muscle and can be comprehensively described by a simple mathematical model. The model accounts for the blood flow during hypoxia, anemia, hypocapnia, and hypercapnia. The main hypothetical basis of the model is that these various challenges, singly or in combination, act via a common regulatory pathway: the regulation of intracellular hydrogen ion concentration. This regulation is achieved by membrane transport of strongly dissociated ions to control their intracellular concentrations. The model assumes that smooth muscle vasoconstriction and vasodilation and hence cerebral blood flow, are proportional to the intracellular hydrogen ion concentration. Model predictions of the cerebral blood flow responses to hypoxia, anemia, hypocapnia, and hypercapnia match the form of observed responses, providing some confidence that the theories on which the model is based have some merit.
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Affiliation(s)
- James Duffin
- Department of Anesthesia and Pain Management, University of Toronto, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Thornhill Research Inc., Toronto, ON, Canada
- University Health Network, Toronto, ON, Canada
| | - David J. Mikulis
- Division of Neuroradiology Imaging, Joint Department of Medical Imaging, University Health Network, Toronto, ON, Canada
| | - Joseph A. Fisher
- Department of Anesthesia and Pain Management, University of Toronto, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Thornhill Research Inc., Toronto, ON, Canada
- University Health Network, Toronto, ON, Canada
- Faculty of Medicine, Institute of Medical Science, University of Toronto, Toronto, ON, Canada
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206
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Alarcon-Martinez L, Yemisci M, Dalkara T. Pericyte morphology and function. Histol Histopathol 2021; 36:633-643. [PMID: 33595091 DOI: 10.14670/hh-18-314] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The proper delivery of blood is essential for healthy neuronal function. The anatomical substrate for this precise mechanism is the neurovascular unit, which is formed by neurons, glial cells, endothelia, smooth muscle cells, and pericytes. Based on their particular location on the vessel wall, morphology, and protein expression, pericytes have been proposed as cells capable of regulating capillary blood flow. Pericytes are located around the microvessels, wrapping them with their processes. Their morphology and protein expression substantially vary along the vascular tree. Their contractibility is mediated by a unique cytoskeleton organization formed by filaments of actin that allows pericyte deformability with the consequent mechanical force transferred to the extracellular matrix for changing the diameter. Pericyte ultrastructure is characterized by large mitochondria likely to provide energy to regulate intracellular calcium concentration and fuel contraction. Accordingly, pericytes with compromised energy show a sustained intracellular calcium increase that leads to persistent microvascular constriction. Pericyte morphology is highly plastic and adapted for varying contractile capability along the microvascular tree, making pericytes ideal cells to regulate the capillary blood flow in response to local neuronal activity. Besides the vascular regulation, pericytes also play a role in the maintenance of the blood-brain/retina barrier, neovascularization and angiogenesis, and leukocyte transmigration. Here, we review the morphological and functional features of the pericytes as well as potential specific markers for the study of pericytes in the brain and retina.
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Affiliation(s)
- Luis Alarcon-Martinez
- Department of Neuroscience and Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Université de Montréal, Montréal, QC, Canada.
| | - Muge Yemisci
- Department of Neurology, Faculty of Medicine, Hacettepe University, Ankara, Turkey.,Institute of Neurological Sciences and Psychiatry, Hacettepe University, Ankara, Turkey
| | - Turgay Dalkara
- Institute of Neurological Sciences and Psychiatry, Hacettepe University, Ankara, Turkey
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207
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Józsa TI, Padmos RM, Samuels N, El-Bouri WK, Hoekstra AG, Payne SJ. A porous circulation model of the human brain for in silico clinical trials in ischaemic stroke. Interface Focus 2021; 11:20190127. [PMID: 33343874 PMCID: PMC7739914 DOI: 10.1098/rsfs.2019.0127] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/23/2020] [Indexed: 12/30/2022] Open
Abstract
The advancement of ischaemic stroke treatment relies on resource-intensive experiments and clinical trials. In order to improve ischaemic stroke treatments, such as thrombolysis and thrombectomy, we target the development of computational tools for in silico trials which can partially replace these animal and human experiments with fast simulations. This study proposes a model that will serve as part of a predictive unit within an in silico clinical trial estimating patient outcome as a function of treatment. In particular, the present work aims at the development and evaluation of an organ-scale microcirculation model of the human brain for perfusion prediction. The model relies on a three-compartment porous continuum approach. Firstly, a fast and robust method is established to compute the anisotropic permeability tensors representing arterioles and venules. Secondly, vessel encoded arterial spin labelling magnetic resonance imaging and clustering are employed to create an anatomically accurate mapping between the microcirculation and large arteries by identifying superficial perfusion territories. Thirdly, the parameter space of the problem is reduced by analysing the governing equations and experimental data. Fourthly, a parameter optimization is conducted. Finally, simulations are performed with the tuned model to obtain perfusion maps corresponding to an open and an occluded (ischaemic stroke) scenario. The perfusion map in the occluded vessel scenario shows promising qualitative agreement with computed tomography images of a patient with ischaemic stroke caused by large vessel occlusion. The results highlight that in the case of vessel occlusion (i) identifying perfusion territories is essential to capture the location and extent of underperfused regions and (ii) anisotropic permeability tensors are required to give quantitatively realistic estimation of perfusion change. In the future, the model will be thoroughly validated against experiments.
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Affiliation(s)
- T. I. Józsa
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK
| | - R. M. Padmos
- Computational Science Laboratory, Institute for Informatics, Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, The Netherlands
| | - N. Samuels
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center, Rotterdam 3015 GD, The Netherlands
| | - W. K. El-Bouri
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK
| | - A. G. Hoekstra
- Computational Science Laboratory, Institute for Informatics, Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, The Netherlands
| | - S. J. Payne
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK
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208
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Ter Schiphorst A, Charron S, Hassen WB, Provost C, Naggara O, Benzakoun J, Seners P, Turc G, Baron JC, Oppenheim C. Tissue no-reflow despite full recanalization following thrombectomy for anterior circulation stroke with proximal occlusion: A clinical study. J Cereb Blood Flow Metab 2021; 41:253-266. [PMID: 32960688 PMCID: PMC8370008 DOI: 10.1177/0271678x20954929] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Despite early thrombectomy, a sizeable fraction of acute stroke patients with large vessel occlusion have poor outcome. The no-reflow phenomenon, i.e. impaired microvascular reperfusion despite complete recanalization, may contribute to such "futile recanalizations". Although well reported in animal models, no-reflow is still poorly characterized in man. From a large prospective thrombectomy database, we included all patients with intracranial proximal occlusion, complete recanalization (modified thrombolysis in cerebral infarction score 2c-3), and availability of both baseline and 24 h follow-up MRI including arterial spin labeling perfusion mapping. No-reflow was operationally defined as i) hypoperfusion ≥40% relative to contralateral homologous region, assessed with both visual (two independent investigators) and automatic image analysis, and ii) infarction on follow-up MRI. Thirty-three patients were eligible (median age: 70 years, NIHSS: 18, and stroke onset-to-recanalization delay: 208 min). The operational criteria were met in one patient only, consistently with the visual and automatic analyses. This patient recanalized 160 min after stroke onset and had excellent functional outcome. In our cohort of patients with complete and stable recanalization following thrombectomy for intracranial proximal occlusion, severe ipsilateral hypoperfusion on follow-up imaging associated with newly developed infarction was a rare occurrence. Thus, no-reflow may be infrequent in human stroke and may not substantially contribute to futile recanalizations.
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Affiliation(s)
- Adrien Ter Schiphorst
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France.,Department of Neurology, CHU Montpellier, University of Montpellier, Montpellier, France
| | - Sylvain Charron
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France.,Department of Neuroradiology, Hôpital Sainte-Anne, Université de Paris, Paris, France
| | - Wagih Ben Hassen
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France.,Department of Neuroradiology, Hôpital Sainte-Anne, Université de Paris, Paris, France
| | - Corentin Provost
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France.,Department of Neuroradiology, Hôpital Sainte-Anne, Université de Paris, Paris, France
| | - Olivier Naggara
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France.,Department of Neuroradiology, Hôpital Sainte-Anne, Université de Paris, Paris, France
| | - Joseph Benzakoun
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France.,Department of Neuroradiology, Hôpital Sainte-Anne, Université de Paris, Paris, France
| | - Pierre Seners
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France.,Department of Neurology, Hôpital Sainte-Anne, Université de Paris, Paris, France
| | - Guillaume Turc
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France.,Department of Neurology, Hôpital Sainte-Anne, Université de Paris, Paris, France
| | - Jean-Claude Baron
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France.,Department of Neurology, Hôpital Sainte-Anne, Université de Paris, Paris, France
| | - Catherine Oppenheim
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France.,Department of Neuroradiology, Hôpital Sainte-Anne, Université de Paris, Paris, France
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209
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Abstract
Cancer treatment remains a challenge due to a high level of intra- and intertumoral heterogeneity and the rapid development of chemoresistance. In the brain, this is further hampered by the blood-brain barrier that reduces passive diffusion of drugs to a minimum. Tumors grow invasively and form new blood vessels, also in brain tissue where remodeling of pre-existing vasculature is substantial. The cancer-associated vessels in the brain are considered leaky and thus could facilitate the transport of chemotherapeutic agents. Yet, brain tumors are extremely difficult to treat, and, in this review, we will address how different aspects of the vasculature in brain tumors contribute to this.
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Affiliation(s)
- Casper Hempel
- Dept of Health Technology, Technical University of Denmark, 2800, Kgs Lyngby, Denmark.
| | - Kasper B Johnsen
- Dept of Health Technology, Technical University of Denmark, 2800, Kgs Lyngby, Denmark
| | - Serhii Kostrikov
- Dept of Health Technology, Technical University of Denmark, 2800, Kgs Lyngby, Denmark
| | - Petra Hamerlik
- Brain Tumor Biology, Danish Cancer Society Research Center, 2100, Copenhagen, Denmark
| | - Thomas L Andresen
- Dept of Health Technology, Technical University of Denmark, 2800, Kgs Lyngby, Denmark.
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210
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Pfeiffer T, Li Y, Attwell D. Diverse mechanisms regulating brain energy supply at the capillary level. Curr Opin Neurobiol 2021; 69:41-50. [PMID: 33485189 DOI: 10.1016/j.conb.2020.12.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/28/2020] [Accepted: 12/13/2020] [Indexed: 02/06/2023]
Abstract
Neural information processing depends critically on the brain's energy supply, which is provided in the form of glucose and oxygen in the blood. Regulation of this supply occurs by smooth muscle and contractile pericytes adjusting the diameter of arterioles and capillaries, respectively. Controversies exist over the relative importance of capillary and arteriolar level control, whether enzymatically generated signals or K+ ions are the dominant controller of cerebral blood flow, and the involvement of capillary endothelial cells. Here, we try to synthesise the relevant recent data into a coherent view of how brain energy supply is controlled and suggest approaches to answering key questions.
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Affiliation(s)
- Thomas Pfeiffer
- Department of Neuroscience, Physiology & Pharmacology, University College London Gower Street, London, WC1E 6BT, UK.
| | - Yuening Li
- Department of Neuroscience, Physiology & Pharmacology, University College London Gower Street, London, WC1E 6BT, UK
| | - David Attwell
- Department of Neuroscience, Physiology & Pharmacology, University College London Gower Street, London, WC1E 6BT, UK.
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211
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Gyimesi M, Rauscher AÁ, Suthar SK, Hamow KÁ, Oravecz K, Lőrincz I, Borhegyi Z, Déri MT, Kiss ÁF, Monostory K, Szabó PT, Nag S, Tomasic I, Krans J, Tierney PJ, Kovács M, Kornya L, Málnási-Csizmadia A. Improved Inhibitory and Absorption, Distribution, Metabolism, Excretion, and Toxicology (ADMET) Properties of Blebbistatin Derivatives Indicate That Blebbistatin Scaffold Is Ideal for drug Development Targeting Myosin-2. J Pharmacol Exp Ther 2021; 376:358-373. [PMID: 33468641 DOI: 10.1124/jpet.120.000167] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 10/07/2020] [Indexed: 11/22/2022] Open
Abstract
Blebbistatin, para-nitroblebbistatin (NBleb), and para-aminoblebbistatin (AmBleb) are highly useful tool compounds as they selectively inhibit the ATPase activity of myosin-2 family proteins. Despite the medical importance of the myosin-2 family as drug targets, chemical optimization has not yet provided a promising lead for drug development because previous structure-activity-relationship studies were limited to a single myosin-2 isoform. Here we evaluated the potential of blebbistatin scaffold for drug development and found that D-ring substitutions can fine-tune isoform specificity, absorption-distribution-metabolism-excretion, and toxicological properties. We defined the inhibitory properties of NBleb and AmBleb on seven different myosin-2 isoforms, which revealed an unexpected potential for isoform specific inhibition. We also found that NBleb metabolizes six times slower than blebbistatin and AmBleb in rats, whereas AmBleb metabolizes two times slower than blebbistatin and NBleb in human, and that AmBleb accumulates in muscle tissues. Moreover, mutagenicity was also greatly reduced in case of AmBleb. These results demonstrate that small substitutions have beneficial functional and pharmacological consequences, which highlight the potential of the blebbistatin scaffold for drug development targeting myosin-2 family proteins and delineate a route for defining the chemical properties of further derivatives to be developed. SIGNIFICANCE STATEMENT: Small substitutions on the blebbistatin scaffold have beneficial functional and pharmacological consequences, highlighting their potential in drug development targeting myosin-2 family proteins.
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Affiliation(s)
- Máté Gyimesi
- Department of Biochemistry, Eötvös Loránd University, Budapest and Martonvásár, Hungary (M.G., K.O., I.L., Z.B., M.K., A.M.-C.); MTA-ELTE Motor Pharmacology Research Group, Budapest, Hungary (M.G., M.K., A.M.-C.); Motorharma Ltd., Budapest, Hungary (A.Á.R.); Printnet Ltd., Budapest, Hungary (S.K.S., I.L.); Plant Protection Institute, Centre for Agricultural Research, Martonvásár, Hungary (K.Á.H.); Metabolic Drug Interactions Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary (M.T.D., Á.F.K., K.M.); Research Centre for Natural Sciences, Instrumentation Center, MS Metabolomic Research Laboratory, Budapest, Hungary (P.T.S.); Department of Biology, MyoKardia Inc., Brisbane, California (S.N., I.T.); Department of Neuroscience, Western New England University, Springfield, Massachusetts (J.K., P.J.T.); and Central Hospital of Southern Pest, National Institute of Hematology and Infectious Diseases, Budapest, Hungary (L.K.)
| | - Anna Á Rauscher
- Department of Biochemistry, Eötvös Loránd University, Budapest and Martonvásár, Hungary (M.G., K.O., I.L., Z.B., M.K., A.M.-C.); MTA-ELTE Motor Pharmacology Research Group, Budapest, Hungary (M.G., M.K., A.M.-C.); Motorharma Ltd., Budapest, Hungary (A.Á.R.); Printnet Ltd., Budapest, Hungary (S.K.S., I.L.); Plant Protection Institute, Centre for Agricultural Research, Martonvásár, Hungary (K.Á.H.); Metabolic Drug Interactions Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary (M.T.D., Á.F.K., K.M.); Research Centre for Natural Sciences, Instrumentation Center, MS Metabolomic Research Laboratory, Budapest, Hungary (P.T.S.); Department of Biology, MyoKardia Inc., Brisbane, California (S.N., I.T.); Department of Neuroscience, Western New England University, Springfield, Massachusetts (J.K., P.J.T.); and Central Hospital of Southern Pest, National Institute of Hematology and Infectious Diseases, Budapest, Hungary (L.K.)
| | - Sharad Kumar Suthar
- Department of Biochemistry, Eötvös Loránd University, Budapest and Martonvásár, Hungary (M.G., K.O., I.L., Z.B., M.K., A.M.-C.); MTA-ELTE Motor Pharmacology Research Group, Budapest, Hungary (M.G., M.K., A.M.-C.); Motorharma Ltd., Budapest, Hungary (A.Á.R.); Printnet Ltd., Budapest, Hungary (S.K.S., I.L.); Plant Protection Institute, Centre for Agricultural Research, Martonvásár, Hungary (K.Á.H.); Metabolic Drug Interactions Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary (M.T.D., Á.F.K., K.M.); Research Centre for Natural Sciences, Instrumentation Center, MS Metabolomic Research Laboratory, Budapest, Hungary (P.T.S.); Department of Biology, MyoKardia Inc., Brisbane, California (S.N., I.T.); Department of Neuroscience, Western New England University, Springfield, Massachusetts (J.K., P.J.T.); and Central Hospital of Southern Pest, National Institute of Hematology and Infectious Diseases, Budapest, Hungary (L.K.)
| | - Kamirán Á Hamow
- Department of Biochemistry, Eötvös Loránd University, Budapest and Martonvásár, Hungary (M.G., K.O., I.L., Z.B., M.K., A.M.-C.); MTA-ELTE Motor Pharmacology Research Group, Budapest, Hungary (M.G., M.K., A.M.-C.); Motorharma Ltd., Budapest, Hungary (A.Á.R.); Printnet Ltd., Budapest, Hungary (S.K.S., I.L.); Plant Protection Institute, Centre for Agricultural Research, Martonvásár, Hungary (K.Á.H.); Metabolic Drug Interactions Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary (M.T.D., Á.F.K., K.M.); Research Centre for Natural Sciences, Instrumentation Center, MS Metabolomic Research Laboratory, Budapest, Hungary (P.T.S.); Department of Biology, MyoKardia Inc., Brisbane, California (S.N., I.T.); Department of Neuroscience, Western New England University, Springfield, Massachusetts (J.K., P.J.T.); and Central Hospital of Southern Pest, National Institute of Hematology and Infectious Diseases, Budapest, Hungary (L.K.)
| | - Kinga Oravecz
- Department of Biochemistry, Eötvös Loránd University, Budapest and Martonvásár, Hungary (M.G., K.O., I.L., Z.B., M.K., A.M.-C.); MTA-ELTE Motor Pharmacology Research Group, Budapest, Hungary (M.G., M.K., A.M.-C.); Motorharma Ltd., Budapest, Hungary (A.Á.R.); Printnet Ltd., Budapest, Hungary (S.K.S., I.L.); Plant Protection Institute, Centre for Agricultural Research, Martonvásár, Hungary (K.Á.H.); Metabolic Drug Interactions Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary (M.T.D., Á.F.K., K.M.); Research Centre for Natural Sciences, Instrumentation Center, MS Metabolomic Research Laboratory, Budapest, Hungary (P.T.S.); Department of Biology, MyoKardia Inc., Brisbane, California (S.N., I.T.); Department of Neuroscience, Western New England University, Springfield, Massachusetts (J.K., P.J.T.); and Central Hospital of Southern Pest, National Institute of Hematology and Infectious Diseases, Budapest, Hungary (L.K.)
| | - István Lőrincz
- Department of Biochemistry, Eötvös Loránd University, Budapest and Martonvásár, Hungary (M.G., K.O., I.L., Z.B., M.K., A.M.-C.); MTA-ELTE Motor Pharmacology Research Group, Budapest, Hungary (M.G., M.K., A.M.-C.); Motorharma Ltd., Budapest, Hungary (A.Á.R.); Printnet Ltd., Budapest, Hungary (S.K.S., I.L.); Plant Protection Institute, Centre for Agricultural Research, Martonvásár, Hungary (K.Á.H.); Metabolic Drug Interactions Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary (M.T.D., Á.F.K., K.M.); Research Centre for Natural Sciences, Instrumentation Center, MS Metabolomic Research Laboratory, Budapest, Hungary (P.T.S.); Department of Biology, MyoKardia Inc., Brisbane, California (S.N., I.T.); Department of Neuroscience, Western New England University, Springfield, Massachusetts (J.K., P.J.T.); and Central Hospital of Southern Pest, National Institute of Hematology and Infectious Diseases, Budapest, Hungary (L.K.)
| | - Zsolt Borhegyi
- Department of Biochemistry, Eötvös Loránd University, Budapest and Martonvásár, Hungary (M.G., K.O., I.L., Z.B., M.K., A.M.-C.); MTA-ELTE Motor Pharmacology Research Group, Budapest, Hungary (M.G., M.K., A.M.-C.); Motorharma Ltd., Budapest, Hungary (A.Á.R.); Printnet Ltd., Budapest, Hungary (S.K.S., I.L.); Plant Protection Institute, Centre for Agricultural Research, Martonvásár, Hungary (K.Á.H.); Metabolic Drug Interactions Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary (M.T.D., Á.F.K., K.M.); Research Centre for Natural Sciences, Instrumentation Center, MS Metabolomic Research Laboratory, Budapest, Hungary (P.T.S.); Department of Biology, MyoKardia Inc., Brisbane, California (S.N., I.T.); Department of Neuroscience, Western New England University, Springfield, Massachusetts (J.K., P.J.T.); and Central Hospital of Southern Pest, National Institute of Hematology and Infectious Diseases, Budapest, Hungary (L.K.)
| | - Máté T Déri
- Department of Biochemistry, Eötvös Loránd University, Budapest and Martonvásár, Hungary (M.G., K.O., I.L., Z.B., M.K., A.M.-C.); MTA-ELTE Motor Pharmacology Research Group, Budapest, Hungary (M.G., M.K., A.M.-C.); Motorharma Ltd., Budapest, Hungary (A.Á.R.); Printnet Ltd., Budapest, Hungary (S.K.S., I.L.); Plant Protection Institute, Centre for Agricultural Research, Martonvásár, Hungary (K.Á.H.); Metabolic Drug Interactions Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary (M.T.D., Á.F.K., K.M.); Research Centre for Natural Sciences, Instrumentation Center, MS Metabolomic Research Laboratory, Budapest, Hungary (P.T.S.); Department of Biology, MyoKardia Inc., Brisbane, California (S.N., I.T.); Department of Neuroscience, Western New England University, Springfield, Massachusetts (J.K., P.J.T.); and Central Hospital of Southern Pest, National Institute of Hematology and Infectious Diseases, Budapest, Hungary (L.K.)
| | - Ádám F Kiss
- Department of Biochemistry, Eötvös Loránd University, Budapest and Martonvásár, Hungary (M.G., K.O., I.L., Z.B., M.K., A.M.-C.); MTA-ELTE Motor Pharmacology Research Group, Budapest, Hungary (M.G., M.K., A.M.-C.); Motorharma Ltd., Budapest, Hungary (A.Á.R.); Printnet Ltd., Budapest, Hungary (S.K.S., I.L.); Plant Protection Institute, Centre for Agricultural Research, Martonvásár, Hungary (K.Á.H.); Metabolic Drug Interactions Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary (M.T.D., Á.F.K., K.M.); Research Centre for Natural Sciences, Instrumentation Center, MS Metabolomic Research Laboratory, Budapest, Hungary (P.T.S.); Department of Biology, MyoKardia Inc., Brisbane, California (S.N., I.T.); Department of Neuroscience, Western New England University, Springfield, Massachusetts (J.K., P.J.T.); and Central Hospital of Southern Pest, National Institute of Hematology and Infectious Diseases, Budapest, Hungary (L.K.)
| | - Katalin Monostory
- Department of Biochemistry, Eötvös Loránd University, Budapest and Martonvásár, Hungary (M.G., K.O., I.L., Z.B., M.K., A.M.-C.); MTA-ELTE Motor Pharmacology Research Group, Budapest, Hungary (M.G., M.K., A.M.-C.); Motorharma Ltd., Budapest, Hungary (A.Á.R.); Printnet Ltd., Budapest, Hungary (S.K.S., I.L.); Plant Protection Institute, Centre for Agricultural Research, Martonvásár, Hungary (K.Á.H.); Metabolic Drug Interactions Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary (M.T.D., Á.F.K., K.M.); Research Centre for Natural Sciences, Instrumentation Center, MS Metabolomic Research Laboratory, Budapest, Hungary (P.T.S.); Department of Biology, MyoKardia Inc., Brisbane, California (S.N., I.T.); Department of Neuroscience, Western New England University, Springfield, Massachusetts (J.K., P.J.T.); and Central Hospital of Southern Pest, National Institute of Hematology and Infectious Diseases, Budapest, Hungary (L.K.)
| | - Pál Tamás Szabó
- Department of Biochemistry, Eötvös Loránd University, Budapest and Martonvásár, Hungary (M.G., K.O., I.L., Z.B., M.K., A.M.-C.); MTA-ELTE Motor Pharmacology Research Group, Budapest, Hungary (M.G., M.K., A.M.-C.); Motorharma Ltd., Budapest, Hungary (A.Á.R.); Printnet Ltd., Budapest, Hungary (S.K.S., I.L.); Plant Protection Institute, Centre for Agricultural Research, Martonvásár, Hungary (K.Á.H.); Metabolic Drug Interactions Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary (M.T.D., Á.F.K., K.M.); Research Centre for Natural Sciences, Instrumentation Center, MS Metabolomic Research Laboratory, Budapest, Hungary (P.T.S.); Department of Biology, MyoKardia Inc., Brisbane, California (S.N., I.T.); Department of Neuroscience, Western New England University, Springfield, Massachusetts (J.K., P.J.T.); and Central Hospital of Southern Pest, National Institute of Hematology and Infectious Diseases, Budapest, Hungary (L.K.)
| | - Suman Nag
- Department of Biochemistry, Eötvös Loránd University, Budapest and Martonvásár, Hungary (M.G., K.O., I.L., Z.B., M.K., A.M.-C.); MTA-ELTE Motor Pharmacology Research Group, Budapest, Hungary (M.G., M.K., A.M.-C.); Motorharma Ltd., Budapest, Hungary (A.Á.R.); Printnet Ltd., Budapest, Hungary (S.K.S., I.L.); Plant Protection Institute, Centre for Agricultural Research, Martonvásár, Hungary (K.Á.H.); Metabolic Drug Interactions Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary (M.T.D., Á.F.K., K.M.); Research Centre for Natural Sciences, Instrumentation Center, MS Metabolomic Research Laboratory, Budapest, Hungary (P.T.S.); Department of Biology, MyoKardia Inc., Brisbane, California (S.N., I.T.); Department of Neuroscience, Western New England University, Springfield, Massachusetts (J.K., P.J.T.); and Central Hospital of Southern Pest, National Institute of Hematology and Infectious Diseases, Budapest, Hungary (L.K.)
| | - Ivan Tomasic
- Department of Biochemistry, Eötvös Loránd University, Budapest and Martonvásár, Hungary (M.G., K.O., I.L., Z.B., M.K., A.M.-C.); MTA-ELTE Motor Pharmacology Research Group, Budapest, Hungary (M.G., M.K., A.M.-C.); Motorharma Ltd., Budapest, Hungary (A.Á.R.); Printnet Ltd., Budapest, Hungary (S.K.S., I.L.); Plant Protection Institute, Centre for Agricultural Research, Martonvásár, Hungary (K.Á.H.); Metabolic Drug Interactions Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary (M.T.D., Á.F.K., K.M.); Research Centre for Natural Sciences, Instrumentation Center, MS Metabolomic Research Laboratory, Budapest, Hungary (P.T.S.); Department of Biology, MyoKardia Inc., Brisbane, California (S.N., I.T.); Department of Neuroscience, Western New England University, Springfield, Massachusetts (J.K., P.J.T.); and Central Hospital of Southern Pest, National Institute of Hematology and Infectious Diseases, Budapest, Hungary (L.K.)
| | - Jacob Krans
- Department of Biochemistry, Eötvös Loránd University, Budapest and Martonvásár, Hungary (M.G., K.O., I.L., Z.B., M.K., A.M.-C.); MTA-ELTE Motor Pharmacology Research Group, Budapest, Hungary (M.G., M.K., A.M.-C.); Motorharma Ltd., Budapest, Hungary (A.Á.R.); Printnet Ltd., Budapest, Hungary (S.K.S., I.L.); Plant Protection Institute, Centre for Agricultural Research, Martonvásár, Hungary (K.Á.H.); Metabolic Drug Interactions Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary (M.T.D., Á.F.K., K.M.); Research Centre for Natural Sciences, Instrumentation Center, MS Metabolomic Research Laboratory, Budapest, Hungary (P.T.S.); Department of Biology, MyoKardia Inc., Brisbane, California (S.N., I.T.); Department of Neuroscience, Western New England University, Springfield, Massachusetts (J.K., P.J.T.); and Central Hospital of Southern Pest, National Institute of Hematology and Infectious Diseases, Budapest, Hungary (L.K.)
| | - Patrick J Tierney
- Department of Biochemistry, Eötvös Loránd University, Budapest and Martonvásár, Hungary (M.G., K.O., I.L., Z.B., M.K., A.M.-C.); MTA-ELTE Motor Pharmacology Research Group, Budapest, Hungary (M.G., M.K., A.M.-C.); Motorharma Ltd., Budapest, Hungary (A.Á.R.); Printnet Ltd., Budapest, Hungary (S.K.S., I.L.); Plant Protection Institute, Centre for Agricultural Research, Martonvásár, Hungary (K.Á.H.); Metabolic Drug Interactions Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary (M.T.D., Á.F.K., K.M.); Research Centre for Natural Sciences, Instrumentation Center, MS Metabolomic Research Laboratory, Budapest, Hungary (P.T.S.); Department of Biology, MyoKardia Inc., Brisbane, California (S.N., I.T.); Department of Neuroscience, Western New England University, Springfield, Massachusetts (J.K., P.J.T.); and Central Hospital of Southern Pest, National Institute of Hematology and Infectious Diseases, Budapest, Hungary (L.K.)
| | - Mihály Kovács
- Department of Biochemistry, Eötvös Loránd University, Budapest and Martonvásár, Hungary (M.G., K.O., I.L., Z.B., M.K., A.M.-C.); MTA-ELTE Motor Pharmacology Research Group, Budapest, Hungary (M.G., M.K., A.M.-C.); Motorharma Ltd., Budapest, Hungary (A.Á.R.); Printnet Ltd., Budapest, Hungary (S.K.S., I.L.); Plant Protection Institute, Centre for Agricultural Research, Martonvásár, Hungary (K.Á.H.); Metabolic Drug Interactions Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary (M.T.D., Á.F.K., K.M.); Research Centre for Natural Sciences, Instrumentation Center, MS Metabolomic Research Laboratory, Budapest, Hungary (P.T.S.); Department of Biology, MyoKardia Inc., Brisbane, California (S.N., I.T.); Department of Neuroscience, Western New England University, Springfield, Massachusetts (J.K., P.J.T.); and Central Hospital of Southern Pest, National Institute of Hematology and Infectious Diseases, Budapest, Hungary (L.K.)
| | - László Kornya
- Department of Biochemistry, Eötvös Loránd University, Budapest and Martonvásár, Hungary (M.G., K.O., I.L., Z.B., M.K., A.M.-C.); MTA-ELTE Motor Pharmacology Research Group, Budapest, Hungary (M.G., M.K., A.M.-C.); Motorharma Ltd., Budapest, Hungary (A.Á.R.); Printnet Ltd., Budapest, Hungary (S.K.S., I.L.); Plant Protection Institute, Centre for Agricultural Research, Martonvásár, Hungary (K.Á.H.); Metabolic Drug Interactions Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary (M.T.D., Á.F.K., K.M.); Research Centre for Natural Sciences, Instrumentation Center, MS Metabolomic Research Laboratory, Budapest, Hungary (P.T.S.); Department of Biology, MyoKardia Inc., Brisbane, California (S.N., I.T.); Department of Neuroscience, Western New England University, Springfield, Massachusetts (J.K., P.J.T.); and Central Hospital of Southern Pest, National Institute of Hematology and Infectious Diseases, Budapest, Hungary (L.K.)
| | - András Málnási-Csizmadia
- Department of Biochemistry, Eötvös Loránd University, Budapest and Martonvásár, Hungary (M.G., K.O., I.L., Z.B., M.K., A.M.-C.); MTA-ELTE Motor Pharmacology Research Group, Budapest, Hungary (M.G., M.K., A.M.-C.); Motorharma Ltd., Budapest, Hungary (A.Á.R.); Printnet Ltd., Budapest, Hungary (S.K.S., I.L.); Plant Protection Institute, Centre for Agricultural Research, Martonvásár, Hungary (K.Á.H.); Metabolic Drug Interactions Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary (M.T.D., Á.F.K., K.M.); Research Centre for Natural Sciences, Instrumentation Center, MS Metabolomic Research Laboratory, Budapest, Hungary (P.T.S.); Department of Biology, MyoKardia Inc., Brisbane, California (S.N., I.T.); Department of Neuroscience, Western New England University, Springfield, Massachusetts (J.K., P.J.T.); and Central Hospital of Southern Pest, National Institute of Hematology and Infectious Diseases, Budapest, Hungary (L.K.)
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212
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Underly RG, Shih AY. Rapid, Nitric Oxide Synthesis-Dependent Activation of MMP-9 at Pericyte Somata During Capillary Ischemia in vivo. Front Physiol 2021; 11:619230. [PMID: 33505320 PMCID: PMC7830159 DOI: 10.3389/fphys.2020.619230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 12/10/2020] [Indexed: 11/28/2022] Open
Abstract
Nitric oxide serves essential roles in normal vascular physiology, but paradoxically contributes to vascular pathology in disease. During brain ischemia, aberrant nitric oxide levels can cause cellular injury through induction of nitrosative/oxidative stress and post-translational activation of matrix-metalloproteinase-9 (MMP-9). We recently demonstrated that brain pericyte somata were associated with very early and localized MMP-9 activation along capillaries during cerebral ischemia, leading to focal blood-brain barrier disruption. Here, we tested whether this effect was dependent upon nitric oxide production. In vivo two-photon imaging was used to directly visualize MMP9 activity using a FITC-gelatin probe and leakage of intravenous dye during photothrombotically induced capillary ischemia. Results showed that the NOS inhibitor, L-NIL, at concentrations affecting both iNOS and constitutive NOS isoforms, attenuated capillary leakage at pericyte soma-specific locations and substantially reduced FITC-gelatin cleavage. We also found that combined administration of L-NIL and anisomycin, an inhibitor of protein synthesis, led to near complete elimination of FITC-gelatin cleavage and vascular leakage. These results indicate that both nitric oxide synthase and new protein synthesis are involved in the rapid activation of MMP-9 at somata of capillary pericytes during ischemia.
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Affiliation(s)
- Robert G Underly
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States
| | - Andy Y Shih
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States.,Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, United States.,Department of Pediatrics, University of Washington, Seattle, WA, United States.,Department of Bioengineering, University of Washington, Seattle, WA, United States
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213
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Howarth C, Mishra A, Hall CN. More than just summed neuronal activity: how multiple cell types shape the BOLD response. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190630. [PMID: 33190598 PMCID: PMC7116385 DOI: 10.1098/rstb.2019.0630] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/22/2020] [Indexed: 12/11/2022] Open
Abstract
Functional neuroimaging techniques are widely applied to investigations of human cognition and disease. The most commonly used among these is blood oxygen level-dependent (BOLD) functional magnetic resonance imaging. The BOLD signal occurs because neural activity induces an increase in local blood supply to support the increased metabolism that occurs during activity. This supply usually outmatches demand, resulting in an increase in oxygenated blood in an active brain region, and a corresponding decrease in deoxygenated blood, which generates the BOLD signal. Hence, the BOLD response is shaped by an integration of local oxygen use, through metabolism, and supply, in the blood. To understand what information is carried in BOLD signals, we must understand how several cell types in the brain-local excitatory neurons, inhibitory neurons, astrocytes and vascular cells (pericytes, vascular smooth muscle and endothelial cells), and their modulation by ascending projection neurons-contribute to both metabolism and haemodynamic changes. Here, we review the contributions of each cell type to the regulation of cerebral blood flow and metabolism, and discuss situations where a simplified interpretation of the BOLD response as reporting local excitatory activity may misrepresent important biological phenomena, for example with regards to arousal states, ageing and neurological disease. This article is part of the theme issue 'Key relationships between non-invasive functional neuroimaging and the underlying neuronal activity'.
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Affiliation(s)
- Clare Howarth
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - Anusha Mishra
- Department of Neurology, Jungers Center for Neurosciences Research, and Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR 97239, USA
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214
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Urrutia AA, Guan N, Mesa‐Ciller C, Afzal A, Davidoff O, Haase VH. Inactivation of HIF-prolyl 4-hydroxylases 1, 2 and 3 in NG2-expressing cells induces HIF2-mediated neurovascular expansion independent of erythropoietin. Acta Physiol (Oxf) 2021; 231:e13547. [PMID: 32846048 PMCID: PMC7757172 DOI: 10.1111/apha.13547] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/23/2020] [Accepted: 08/11/2020] [Indexed: 12/14/2022]
Abstract
AIM NG2 cells in the brain are comprised of pericytes and NG2 glia and play an important role in the execution of cerebral hypoxia responses, including the induction of erythropoietin (EPO) in pericytes. Oxygen-dependent angiogenic responses are regulated by hypoxia-inducible factor (HIF), the activity of which is controlled by prolyl 4-hydroxylase domain (PHD) dioxygenases and the von Hippel-Lindau (VHL) tumour suppressor. However, the role of NG2 cells in HIF-regulated cerebral vascular homeostasis is incompletely understood. METHODS To examine the HIF/PHD/VHL axis in neurovascular homeostasis, we used a Cre-loxP-based genetic approach in mice and targeted Vhl, Epo, Phd1, Phd2, Phd3 and Hif2a in NG2 cells. Cerebral vasculature was assessed by immunofluorescence, RNA in situ hybridization, gene and protein expression analysis, gel zymography and in situ zymography. RESULTS Vhl inactivation led to a significant increase in angiogenic gene and Epo expression. This was associated with EPO-independent expansion of capillary networks in cortex, striatum and hypothalamus, as well as pericyte proliferation. A comparable phenotype resulted from the combined inactivation of Phd2 and Phd3, but not from Phd2 inactivation alone. Concomitant PHD1 function loss led to further expansion of the neurovasculature. Genetic inactivation of Hif2a in Phd1/Phd2/Phd3 triple mutant mice resulted in normal cerebral vasculature. CONCLUSION Our studies establish (a) that HIF2 activation in NG2 cells promotes neurovascular expansion and remodelling independently of EPO, (b) that HIF2 activity in NG2 cells is co-controlled by PHD2 and PHD3 and (c) that PHD1 modulates HIF2 transcriptional responses when PHD2 and PHD3 are inactive.
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Affiliation(s)
- Andrés A. Urrutia
- Department of MedicineVanderbilt University School of MedicineNashvilleTNUSA
- Unidad de Investigación Hospital de Santa CristinaInstituto de Investigación del Hospital Universitario La PrincesaUniversidad Autónoma de MadridMadridSpain
| | - Nan Guan
- Department of MedicineVanderbilt University School of MedicineNashvilleTNUSA
- Division of NephrologyHuashan Hospital and Nephrology Research InstituteFudan UniversityShanghaiChina
| | - Claudia Mesa‐Ciller
- Unidad de Investigación Hospital de Santa CristinaInstituto de Investigación del Hospital Universitario La PrincesaUniversidad Autónoma de MadridMadridSpain
| | - Aqeela Afzal
- Department of NeurosurgeryVanderbilt University School of MedicineNashvilleTNUSA
| | - Olena Davidoff
- Department of MedicineVanderbilt University School of MedicineNashvilleTNUSA
| | - Volker H. Haase
- Department of MedicineVanderbilt University School of MedicineNashvilleTNUSA
- Division of Integrative PhysiologyDepartment of Medical Cell BiologyUppsala UniversitetUppsalaSweden
- Department of Molecular Physiology and Biophysics and Program in Cancer BiologyVanderbilt University School of MedicineNashvilleTNUSA
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215
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Blevins BL, Vinters HV, Love S, Wilcock DM, Grinberg LT, Schneider JA, Kalaria RN, Katsumata Y, Gold BT, Wang DJJ, Ma SJ, Shade LMP, Fardo DW, Hartz AMS, Jicha GA, Nelson KB, Magaki SD, Schmitt FA, Teylan MA, Ighodaro ET, Phe P, Abner EL, Cykowski MD, Van Eldik LJ, Nelson PT. Brain arteriolosclerosis. Acta Neuropathol 2021; 141:1-24. [PMID: 33098484 PMCID: PMC8503820 DOI: 10.1007/s00401-020-02235-6] [Citation(s) in RCA: 70] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 10/04/2020] [Accepted: 10/05/2020] [Indexed: 12/14/2022]
Abstract
Brain arteriolosclerosis (B-ASC), characterized by pathologic arteriolar wall thickening, is a common finding at autopsy in aged persons and is associated with cognitive impairment. Hypertension and diabetes are widely recognized as risk factors for B-ASC. Recent research indicates other and more complex risk factors and pathogenetic mechanisms. Here, we describe aspects of the unique architecture of brain arterioles, histomorphologic features of B-ASC, relevant neuroimaging findings, epidemiology and association with aging, established genetic risk factors, and the co-occurrence of B-ASC with other neuropathologic conditions such as Alzheimer's disease and limbic-predominant age-related TDP-43 encephalopathy (LATE). There may also be complex physiologic interactions between metabolic syndrome (e.g., hypertension and inflammation) and brain arteriolar pathology. Although there is no universally applied diagnostic methodology, several classification schemes and neuroimaging techniques are used to diagnose and categorize cerebral small vessel disease pathologies that include B-ASC, microinfarcts, microbleeds, lacunar infarcts, and cerebral amyloid angiopathy (CAA). In clinical-pathologic studies that factored in comorbid diseases, B-ASC was independently associated with impairments of global cognition, episodic memory, working memory, and perceptual speed, and has been linked to autonomic dysfunction and motor symptoms including parkinsonism. We conclude by discussing critical knowledge gaps related to B-ASC and suggest that there are probably subcategories of B-ASC that differ in pathogenesis. Observed in over 80% of autopsied individuals beyond 80 years of age, B-ASC is a complex and under-studied contributor to neurologic disability.
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Affiliation(s)
- Brittney L Blevins
- Department of Neuroscience, University Kentucky, Lexington, KY, 40536, USA
| | - Harry V Vinters
- Department of Pathology and Laboratory Medicine, David Geffen SOM at UCLA and Ronald Reagan UCLA Medical Center, Los Angeles, CA, 90095-1732, USA
| | - Seth Love
- University of Bristol and Southmead Hospital, Bristol, BS10 5NB, UK
| | - Donna M Wilcock
- Sanders-Brown Center on Aging, Department of Neuroscience, University Kentucky, Lexington, KY, 40536, USA
| | - Lea T Grinberg
- Department of Neurology and Pathology, UCSF, San Francisco, CA, USA
- Global Brain Health Institute, UCSF, San Francisco, CA, USA
- LIM-22, Department of Pathology, University of Sao Paulo Medical School, São Paulo, Brazil
| | - Julie A Schneider
- Departments of Neurology and Pathology, Rush University Medical Center, Chicago, IL, 60612, USA
| | - Rajesh N Kalaria
- Translational and Clinical Research Institute, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne, NE4 5PL, UK
| | - Yuriko Katsumata
- Sanders-Brown Center on Aging, Department of Biostatistics, University Kentucky, Lexington, KY, 40536, USA
| | - Brian T Gold
- Sanders-Brown Center on Aging, Department of Neuroscience, University Kentucky, Lexington, KY, 40536, USA
| | - Danny J J Wang
- Laboratory of FMRI Technology (LOFT), USC Mark and Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, USA
| | - Samantha J Ma
- Laboratory of FMRI Technology (LOFT), USC Mark and Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, USA
| | - Lincoln M P Shade
- Sanders-Brown Center on Aging, Department of Biostatistics, University Kentucky, Lexington, KY, 40536, USA
| | - David W Fardo
- Sanders-Brown Center on Aging, Department of Biostatistics, University Kentucky, Lexington, KY, 40536, USA
| | - Anika M S Hartz
- Sanders-Brown Center on Aging, Department of Pharmacology and Nutritional Sciences, University Kentucky, Lexington, KY, 40536, USA
| | - Gregory A Jicha
- Sanders-Brown Center on Aging, Department of Neurology, University Kentucky, Lexington, KY, 40536, USA
| | | | - Shino D Magaki
- Department of Pathology and Laboratory Medicine, David Geffen SOM at UCLA and Ronald Reagan UCLA Medical Center, Los Angeles, CA, 90095-1732, USA
| | - Frederick A Schmitt
- Sanders-Brown Center on Aging, Department of Neurology, University Kentucky, Lexington, KY, 40536, USA
| | - Merilee A Teylan
- Department of Epidemiology, University Washington, Seattle, WA, 98105, USA
| | | | - Panhavuth Phe
- Sanders-Brown Center on Aging, University Kentucky, Lexington, KY, 40536, USA
| | - Erin L Abner
- Sanders-Brown Center on Aging, Department of Epidemiology, University Kentucky, Lexington, KY, 40536, USA
| | - Matthew D Cykowski
- Departments of Pathology and Genomic Medicine and Neurology, Houston Methodist Hospital, Houston, TX, 77030, USA
| | - Linda J Van Eldik
- Sanders-Brown Center on Aging, Department of Neuroscience, University Kentucky, Lexington, KY, 40536, USA
| | - Peter T Nelson
- Sanders-Brown Center on Aging, Department of Pathology, University of Kentucky, Lexington, KY, 40536, USA.
- Rm 311 Sanders-Brown Center on Aging, University of Kentucky, 800 S. Limestone Avenue, Lexington, KY, 40536, USA.
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216
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Gastfriend BD, Stebbins MJ, Du F, Shusta EV, Palecek SP. Differentiation of Brain Pericyte-Like Cells from Human Pluripotent Stem Cell-Derived Neural Crest. Curr Protoc 2021; 1:e21. [PMID: 33484491 PMCID: PMC7839246 DOI: 10.1002/cpz1.21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Brain pericytes regulate diverse aspects of neurovascular development and function, including blood-brain barrier (BBB) induction and maintenance. Primary brain pericytes have been widely employed in coculture-based in vitro models of the BBB, and a method to generate brain pericytes from human pluripotent stem cells (hPSCs) could provide a renewable, genetically tractable source of cells for BBB modeling and studying pericyte roles in development and disease. Here, we describe a protocol to differentiate hPSCs to NG2+ PDGFRβ+ αSMAlow brain pericyte-like cells in 22-25 days through a p75-NGFR+ HNK-1+ neural crest intermediate, which mimics the developmental origin of forebrain pericytes. The resulting brain pericyte-like cells have molecular and functional attributes of brain pericytes. We also provide protocols for maintenance, cryopreservation, and recovery of the neural crest intermediate, and for molecular and functional characterization of the resulting cells. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Differentiation of hPSCs to neural crest Basic Protocol 2: Differentiation of neural crest to brain pericyte-like cells Support Protocol 1: Flow cytometry analysis of neural crest cells Support Protocol 2: Maintenance, cryopreservation, and recovery of neural crest cells Support Protocol 3: Molecular characterization of brain pericyte-like cells Support Protocol 4: Cord formation assay with endothelial cells and brain pericyte-like cells.
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Affiliation(s)
- Benjamin D. Gastfriend
- Department of Chemical and Biological Engineering, University of Wisconsin–Madison, Madison, WI, USA
| | - Matthew J. Stebbins
- Department of Chemical and Biological Engineering, University of Wisconsin–Madison, Madison, WI, USA
| | - Feifan Du
- Department of Chemical and Biological Engineering, University of Wisconsin–Madison, Madison, WI, USA
| | - Eric V. Shusta
- Department of Chemical and Biological Engineering, University of Wisconsin–Madison, Madison, WI, USA
- Department of Neurological Surgery, University of Wisconsin–Madison, Madison, WI, USA
| | - Sean P. Palecek
- Department of Chemical and Biological Engineering, University of Wisconsin–Madison, Madison, WI, USA
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217
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Hariharan A, Weir N, Robertson C, He L, Betsholtz C, Longden TA. The Ion Channel and GPCR Toolkit of Brain Capillary Pericytes. Front Cell Neurosci 2020; 14:601324. [PMID: 33390906 PMCID: PMC7775489 DOI: 10.3389/fncel.2020.601324] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/13/2020] [Indexed: 12/14/2022] Open
Abstract
Brain pericytes reside on the abluminal surface of capillaries, and their processes cover ~90% of the length of the capillary bed. These cells were first described almost 150 years ago (Eberth, 1871; Rouget, 1873) and have been the subject of intense experimental scrutiny in recent years, but their physiological roles remain uncertain and little is known of the complement of signaling elements that they employ to carry out their functions. In this review, we synthesize functional data with single-cell RNAseq screens to explore the ion channel and G protein-coupled receptor (GPCR) toolkit of mesh and thin-strand pericytes of the brain, with the aim of providing a framework for deeper explorations of the molecular mechanisms that govern pericyte physiology. We argue that their complement of channels and receptors ideally positions capillary pericytes to play a central role in adapting blood flow to meet the challenge of satisfying neuronal energy requirements from deep within the capillary bed, by enabling dynamic regulation of their membrane potential to influence the electrical output of the cell. In particular, we outline how genetic and functional evidence suggest an important role for Gs-coupled GPCRs and ATP-sensitive potassium (KATP) channels in this context. We put forth a predictive model for long-range hyperpolarizing electrical signaling from pericytes to upstream arterioles, and detail the TRP and Ca2+ channels and Gq, Gi/o, and G12/13 signaling processes that counterbalance this. We underscore critical questions that need to be addressed to further advance our understanding of the signaling topology of capillary pericytes, and how this contributes to their physiological roles and their dysfunction in disease.
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Affiliation(s)
- Ashwini Hariharan
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Nick Weir
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Colin Robertson
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Liqun He
- Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Christer Betsholtz
- Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.,Department of Medicine Huddinge (MedH), Karolinska Institutet & Integrated Cardio Metabolic Centre, Huddinge, Sweden
| | - Thomas A Longden
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
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218
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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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219
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Hørlyck S, Cai C, Helms HCC, Lauritzen M, Brodin B. ATP induces contraction of cultured brain capillary pericytes via activation of P2Y-type purinergic receptors. Am J Physiol Heart Circ Physiol 2020; 320:H699-H712. [PMID: 33306443 DOI: 10.1152/ajpheart.00560.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Brain capillary pericytes have been suggested to play a role in the regulation of cerebral blood flow under physiological and pathophysiological conditions. ATP has been shown to cause constriction of capillaries under ischemic conditions and suggested to be involved in the "no-reflow" phenomenon. To investigate the effects of extracellular ATP on pericyte cell contraction, we studied purinergic receptor activation of cultured bovine brain capillary pericytes. We measured intracellular Ca2+ concentration ([Ca2+]i) responses to purinergic agonists with the fluorescent indicators fura-2 and Cal-520 and estimated contraction of pericytes as relative change in cell area, using real-time confocal imaging. Addition of ATP caused an increase in cytosolic calcium and contraction of the brain capillary pericytes, both reversible and inhibited by the purinergic receptor antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS). Furthermore, we demonstrated that ATP-induced contraction could be eliminated by intracellular calcium chelation with BAPTA, indicating that the contraction was mediated via purinergic P2-type receptor-mediated [Ca2+]i signaling. ATP stimulation induced inositol triphosphate signaling, consistent with the notion of P2Y receptor activation. Receptor profiling studies demonstrated the presence of P2Y1 and P2Y2 receptors, using ATP, UTP, ADP, and the subtype specific agonists MRS2365 (P2Y1) and 2-thio-UTP (P2Y2). Addition of specific P2X agonists only caused an [Ca2+]i increase at high concentrations, attributed to activation of inositol triphosphate signaling. Our results suggest that contraction of brain capillary pericytes in vitro by activation of P2Y-type purinergic receptors is caused by intracellular calcium release. This adds more mechanistic understanding of the role of pericytes in vessel constriction and points toward P2Y receptors as potential therapeutic targets.NEW & NOTEWORTHY The study concerns brain capillary pericytes, which have been suggested to play a role in the regulation of cerebral blood flow. We show that extracellular ATP causes contraction of primary brain pericytes by stimulation of purinergic receptors and subsequent release of intracellular Ca2+ concentration ([Ca2+]i). The contraction is mainly mediated through activation of P2Y-receptor subtypes, including P2Y1 and P2Y2. These findings add more mechanistic understanding of the role of pericytes in regulation of capillary blood flow. ATP was earlier suggested to be involved in capillary constriction in brain pathologies, and our study gives a detailed account of a part of this important mechanism.
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Affiliation(s)
- Sofie Hørlyck
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Changsi Cai
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Martin Lauritzen
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Neurophysiology, Rigshospitalet, Copenhagen, Denmark
| | - Birger Brodin
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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220
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Imaging and optogenetic modulation of vascular mural cells in the live brain. Nat Protoc 2020; 16:472-496. [PMID: 33299155 DOI: 10.1038/s41596-020-00425-w] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 09/24/2020] [Indexed: 12/17/2022]
Abstract
Mural cells (smooth muscle cells and pericytes) are integral components of brain blood vessels that play important roles in vascular formation, blood-brain barrier maintenance, and regulation of regional cerebral blood flow (rCBF). These cells are implicated in conditions ranging from developmental vascular disorders to age-related neurodegenerative diseases. Here we present complementary tools for cell labeling with transgenic mice and organic dyes that allow high-resolution intravital imaging of the different mural cell subtypes. We also provide detailed methodologies for imaging of spontaneous and neural activity-evoked calcium transients in mural cells. In addition, we describe strategies for single- and two-photon optogenetics that allow manipulation of the activity of individual and small clusters of mural cells. Together with measurements of diameter and flow in individual brain microvessels, calcium imaging and optogenetics allow the investigation of pericyte and smooth muscle cell physiology and their role in regulating rCBF. We also demonstrate the utility of these tools to investigate mural cells in the context of Alzheimer's disease and cerebral ischemia mouse models. Thus, these methods can be used to reveal the functional and structural heterogeneity of mural cells in vivo, and allow detailed cellular studies of the normal function and pathophysiology of mural cells in a variety of disease models. The implementation of this protocol can take from several hours to days depending on the intended applications.
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221
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Ross JM, Kim C, Allen D, Crouch EE, Narsinh K, Cooke DL, Abla AA, Nowakowski TJ, Winkler EA. The Expanding Cell Diversity of the Brain Vasculature. Front Physiol 2020; 11:600767. [PMID: 33343397 PMCID: PMC7744630 DOI: 10.3389/fphys.2020.600767] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/10/2020] [Indexed: 12/12/2022] Open
Abstract
The cerebrovasculature is essential to brain health and is tasked with ensuring adequate delivery of oxygen and metabolic precursors to ensure normal neurologic function. This is coordinated through a dynamic, multi-directional cellular interplay between vascular, neuronal, and glial cells. Molecular exchanges across the blood-brain barrier or the close matching of regional blood flow with brain activation are not uniformly assigned to arteries, capillaries, and veins. Evidence has supported functional segmentation of the brain vasculature. This is achieved in part through morphologic or transcriptional heterogeneity of brain vascular cells-including endothelium, pericytes, and vascular smooth muscle. Advances with single cell genomic technologies have shown increasing cell complexity of the brain vasculature identifying previously unknown cell types and further subclassifying transcriptional diversity in cardinal vascular cell types. Cell-type specific molecular transitions or zonations have been identified. In this review, we summarize emerging evidence for the expanding vascular cell diversity in the brain and how this may provide a cellular basis for functional segmentation along the arterial-venous axis.
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Affiliation(s)
- Jayden M. Ross
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA, United States
- Department of Anatomy, University of California, San Francisco, San Francisco, CA, United States
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA, United States
- The Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, United States
| | - Chang Kim
- Department of Anatomy, University of California, San Francisco, San Francisco, CA, United States
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA, United States
- The Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, United States
| | - Denise Allen
- Department of Anatomy, University of California, San Francisco, San Francisco, CA, United States
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA, United States
- The Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, United States
| | - Elizabeth E. Crouch
- Department of Pediatrics, University of California, San Francisco, San Francisco, CA, United States
| | - Kazim Narsinh
- Department of Radiology, University of California, San Francisco, San Francisco, CA, United States
| | - Daniel L. Cooke
- Department of Radiology, University of California, San Francisco, San Francisco, CA, United States
| | - Adib A. Abla
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Tomasz J. Nowakowski
- Department of Anatomy, University of California, San Francisco, San Francisco, CA, United States
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA, United States
- The Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, United States
- Department of Radiology, University of California, San Francisco, San Francisco, CA, United States
| | - Ethan A. Winkler
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA, United States
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222
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Watson AN, Berthiaume AA, Faino AV, McDowell KP, Bhat NR, Hartmann DA, Shih AY. Mild pericyte deficiency is associated with aberrant brain microvascular flow in aged PDGFRβ +/- mice. J Cereb Blood Flow Metab 2020; 40:2387-2400. [PMID: 31987006 PMCID: PMC7820684 DOI: 10.1177/0271678x19900543] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The receptor tyrosine kinase PDGFRβ is essential for pericyte migration to the endothelium. In mice lacking one allele of PDGFRβ (PDGFRβ+/-), previous reports have described an age-dependent loss of pericytes in the brain, leading to cerebrovascular dysfunction and subsequent neurodegeneration reminiscent of that seen in Alzheimer's disease and vascular dementia. We examined 12-20-month-old PDGFRβ+/- mice to better understand how pericyte loss affects brain microvascular structure and perfusion in vivo. We observed a mild reduction of cortical pericyte number in PDGFRβ+/- mice (27% fewer cell bodies) compared to controls, but no decrease in pericyte coverage of the endothelium. This mild degree of pericyte loss caused no discernable change in cortical microvascular density, length, basal diameter or reactivity to hypercapnia. Yet, it was associated with an increase in basal blood cell velocity, primarily in pre-capillary arterioles. Taken together, our results suggest that mild pericyte loss can lead to aberrant cerebral blood flow despite a lack of apparent effect on microvascular structure and reactivity.
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Affiliation(s)
- Ashley N Watson
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Andree-Anne Berthiaume
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA.,Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA
| | - Anna V Faino
- Children's Core for Biomedical Statistics, Seattle Children's Research Institute, Seattle, WA, USA
| | - Konnor P McDowell
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA.,Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA
| | - Narayan R Bhat
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - David A Hartmann
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Andy Y Shih
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA.,Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA.,Children's Core for Biomedical Statistics, Seattle Children's Research Institute, Seattle, WA, USA.,Department of Pediatrics, University of Washington, Seattle, WA, USA
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223
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Beard DJ, Brown LS, Sutherland BA. The rise of pericytes in neurovascular research. J Cereb Blood Flow Metab 2020; 40:2366-2373. [PMID: 32955956 PMCID: PMC7820692 DOI: 10.1177/0271678x20958497] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 08/06/2020] [Accepted: 08/16/2020] [Indexed: 01/05/2023]
Abstract
The popularity of pericyte research is increasing, and this was not more evident than at the recent 2019 Brain meeting in Yokohama which featured a large number of presentations focused on brain pericyte research, including the Presidential Symposium. In this article, we will provide a history of brain pericyte research, present the results of our analysis showing a substantial increase in brain pericyte research presented at Brain meetings since 2005, suggest reasons for their increased popularity, and comment on what the future holds for brain pericyte research.
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Affiliation(s)
- Daniel J Beard
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, Australia
- Acute Stroke Programme, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Lachlan S Brown
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, Australia
| | - Brad A Sutherland
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, Australia
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224
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Korte N, Nortley R, Attwell D. Cerebral blood flow decrease as an early pathological mechanism in Alzheimer's disease. Acta Neuropathol 2020; 140:793-810. [PMID: 32865691 PMCID: PMC7666276 DOI: 10.1007/s00401-020-02215-w] [Citation(s) in RCA: 142] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 08/15/2020] [Accepted: 08/15/2020] [Indexed: 02/08/2023]
Abstract
Therapies targeting late events in Alzheimer's disease (AD), including aggregation of amyloid beta (Aβ) and hyperphosphorylated tau, have largely failed, probably because they are given after significant neuronal damage has occurred. Biomarkers suggest that the earliest event in AD is a decrease of cerebral blood flow (CBF). This is caused by constriction of capillaries by contractile pericytes, probably evoked by oligomeric Aβ. CBF is also reduced by neutrophil trapping in capillaries and clot formation, perhaps secondary to the capillary constriction. The fall in CBF potentiates neurodegeneration by upregulating the BACE1 enzyme that makes Aβ and by promoting tau hyperphosphorylation. Surprisingly, therefore, CBF reduction may play a crucial role in driving cognitive decline by initiating the amyloid cascade itself, or being caused by and amplifying Aβ production. Here, we review developments in this area that are neglected in current approaches to AD, with the aim of promoting novel mechanism-based therapeutic approaches.
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Affiliation(s)
- Nils Korte
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Ross Nortley
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
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225
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Valle IB, Schuch LF, da Silva JM, Gala-García A, Diniz IMA, Birbrair A, Abreu LG, Silva TA. Pericyte in Oral Squamous Cell Carcinoma: A Systematic Review. Head Neck Pathol 2020; 14:1080-1091. [PMID: 32506378 PMCID: PMC7669928 DOI: 10.1007/s12105-020-01188-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/02/2020] [Indexed: 02/06/2023]
Abstract
The microenvironment of oral cancer is highly dynamic and has been proved to affect tumor progression. Pericytes are blood vessels surrounding cells that have recently gained attention for their roles in vascular and cancer biology. The objective of the present study was to survey the scientific literature for conclusive evidence about whether pericytes are part of blood vessels in oral squamous cell carcinoma (OSCC) and their roles in the tumor microenvironment and clinical outcomes. A systematic electronic search was undertaken in Medline Ovid, PubMed, Web of Science, and Scopus. Eligibility criteria were: publications adopting in vivo models of OSCC that included pericyte detection and assessment by pericyte markers (e.g., α-smooth muscle actin, neuron-glial antigen 2 and platelet-derived growth factor receptor-β). The search yielded seven eligible studies (from 2008 to 2018). The markers most commonly used for pericyte detection were α-smooth muscle actin and neuron-glial antigen 2. The studies reviewed showed the presence of immature vessels exhibiting a reduction of pericyte coverage in OSCC and indicated that anti-cancer therapies could contribute to vessel normalization and pericyte regain. The pericyte population is significantly affected during OSCC development and cancer therapy. While these findings might suggest a role for pericytes in OSCC progression, the limited data available do not allow us to conclude whether they modify the tumor microenvironment and clinical outcome.
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Affiliation(s)
- Isabella Bittencourt Valle
- Department of Oral Surgery and Pathology, School of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Lauren Frenzel Schuch
- Department of Oral Surgery and Pathology, School of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Janine Mayra da Silva
- Department of Oral Surgery and Pathology, School of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Alfonso Gala-García
- Department of Genetics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Ivana Márcia Alves Diniz
- Department of Restorative Dentistry, School of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Alexander Birbrair
- Department of Pathology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Lucas Guimarães Abreu
- Department of Child's and Adolescent's Oral Health, School of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Tarcília Aparecida Silva
- Department of Oral Surgery and Pathology, School of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
- Department of Oral Surgery and Pathology, School of Dentistry, Universidade Federal de Minas Gerais, Av. Pres. Antônio Carlos, 6627, Room 3105. Pampulha, Belo Horizonte, MG, CEP: 31.270-901, Brazil.
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226
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Fukuda M, Poplawsky AJ, Kim SG. Time-dependent spatial specificity of high-resolution fMRI: insights into mesoscopic neurovascular coupling. Philos Trans R Soc Lond B Biol Sci 2020; 376:20190623. [PMID: 33190606 PMCID: PMC7741035 DOI: 10.1098/rstb.2019.0623] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
High-resolution functional magnetic resonance imaging (fMRI) is becoming increasingly popular because of the growing availability of ultra-high magnetic fields which are capable of improving sensitivity and spatial resolution. However, it is debatable whether increased spatial resolutions for haemodynamic-based techniques, like fMRI, can accurately detect the true location of neuronal activity. We have addressed this issue in functional columns and layers of animals with haemoglobin-based optical imaging and different fMRI contrasts, such as blood oxygenation level-dependent, cerebral blood flow and cerebral blood volume fMRI. In this review, we describe empirical evidence primarily from our own studies on how well these fMRI signals are spatially specific to the neuronally active site and discuss insights into neurovascular coupling at the mesoscale. This article is part of the theme issue 'Key relationships between non-invasive functional neuroimaging and the underlying neuronal activity'.
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Affiliation(s)
- Mitsuhiro Fukuda
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Seong-Gi Kim
- Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, South Korea.,Department of Biomedical Engineering, Sungkyunkwan University, Suwon, South Korea
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227
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Fernandez‐Klett F, Brandt L, Fernández‐Zapata C, Abuelnor B, Middeldorp J, Sluijs JA, Curtis M, Faull R, Harris LW, Bahn S, Hol EM, Priller J. Denser brain capillary network with preserved pericytes in Alzheimer's disease. Brain Pathol 2020; 30:1071-1086. [PMID: 32876357 PMCID: PMC8018033 DOI: 10.1111/bpa.12897] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Pericytes are vascular mural cells that surround capillaries of the central nervous system (CNS). They are crucial for brain development and contribute to CNS homeostasis by regulating blood-brain barrier function and cerebral blood flow. It has been suggested that pericytes are lost in Alzheimer's disease (AD), implicating this cell type in disease pathology. Here, we have employed state-of-the-art stereological morphometry techniques as well as tissue clearing and two-photon imaging to assess the distribution of pericytes in two independent cohorts of AD (n = 16 and 13) and non-demented controls (n = 16 and 4). Stereological quantification revealed increased capillary density with a normal pericyte population in the frontal cortex of AD brains, a region with early amyloid β deposition. Two-photon analysis of cleared frontal cortex tissue confirmed the preservation of pericytes in AD cases. These results suggest that pericyte demise is not a general hallmark of AD pathology.
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Affiliation(s)
- Francisco Fernandez‐Klett
- Laboratory of Molecular PsychiatryDepartment of NeuropsychiatryCharité − Universitätsmedizin BerlinBerlinGermany
- Institute for PathologyUniversitätsklinik HalleHalleGermany
| | - Lasse Brandt
- Laboratory of Molecular PsychiatryDepartment of NeuropsychiatryCharité − Universitätsmedizin BerlinBerlinGermany
- Department of Psychiatry and PsychotherapyCharité − Universitätsmedizin BerlinBerlinGermany
| | - Camila Fernández‐Zapata
- Laboratory of Molecular PsychiatryDepartment of NeuropsychiatryCharité − Universitätsmedizin BerlinBerlinGermany
| | - Basim Abuelnor
- Laboratory of Molecular PsychiatryDepartment of NeuropsychiatryCharité − Universitätsmedizin BerlinBerlinGermany
| | - Jinte Middeldorp
- Department of Translational NeuroscienceUniversity Medical Center Utrecht Brain CenterUtrecht UniversityUtrechtThe Netherlands
| | - Jacqueline A. Sluijs
- Department of Translational NeuroscienceUniversity Medical Center Utrecht Brain CenterUtrecht UniversityUtrechtThe Netherlands
| | - Maurice Curtis
- The New Zealand Neurological Foundation Human Brain BankCentre for Brain ResearchUniversity of AucklandAucklandNew Zealand
| | - Richard Faull
- The New Zealand Neurological Foundation Human Brain BankCentre for Brain ResearchUniversity of AucklandAucklandNew Zealand
| | - Laura W. Harris
- Department of Chemical Engineering and BiotechnologyUniversity of CambridgeCambridgeUK
| | - Sabine Bahn
- Department of Chemical Engineering and BiotechnologyUniversity of CambridgeCambridgeUK
| | - Elly M. Hol
- Department of Translational NeuroscienceUniversity Medical Center Utrecht Brain CenterUtrecht UniversityUtrechtThe Netherlands
| | - Josef Priller
- Laboratory of Molecular PsychiatryDepartment of NeuropsychiatryCharité − Universitätsmedizin BerlinBerlinGermany
- Department of Psychiatry and PsychotherapyCharité − Universitätsmedizin BerlinBerlinGermany
- DZNE and BIHBerlinGermany
- University of Edinburgh and UK DRIEdinburghUK
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228
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Epp R, Schmid F, Weber B, Jenny P. Predicting Vessel Diameter Changes to Up-Regulate Biphasic Blood Flow During Activation in Realistic Microvascular Networks. Front Physiol 2020; 11:566303. [PMID: 33178036 PMCID: PMC7596696 DOI: 10.3389/fphys.2020.566303] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 08/14/2020] [Indexed: 12/26/2022] Open
Abstract
A dense network of blood vessels distributes blood to different regions of the brain. To meet the temporarily and spatially varying energy demand resulting from changes in neuronal activity, the vasculature is able to locally up-regulate the blood supply. However, to which extent diameter changes of different vessel types contribute to the up-regulation, as well as the spatial and temporal characteristics of their changes, are currently unknown. Here, we present a new simulation method, which solves an inverse problem to calculate diameter changes of individual blood vessels needed to achieve predefined blood flow distributions in microvascular networks. This allows us to systematically compare the impact of different vessel types in various regulation scenarios. Moreover, the method offers the advantage that it handles the stochastic nature of blood flow originating from tracking the movement of individual red blood cells. Since the inverse problem is formulated for time-averaged pressures and flow rates, a deterministic approach for calculating the diameter changes is used, which allows us to apply the method for large realistic microvascular networks with high-dimensional parameter spaces. Our results obtained in both artificial and realistic microvascular networks reveal that diameter changes at the level of capillaries enable a very localized regulation of blood flow. In scenarios where only larger vessels, i.e., arterioles, are allowed to adapt, the flow increase cannot be confined to a specific activated region and flow changes spread into neighboring regions. Furthermore, relatively small dilations and constrictions of all vessel types can lead to substantial changes of capillary blood flow distributions. This suggests that small scale regulation is necessary to obtain a localized increase in blood flow.
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Affiliation(s)
- Robert Epp
- Institute of Fluid Dynamics, ETH Zurich, Zurich, Switzerland
| | - Franca Schmid
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Patrick Jenny
- Institute of Fluid Dynamics, ETH Zurich, Zurich, Switzerland
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229
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Imanishi A, Ichise H, Fan C, Nakagawa Y, Kuwahara K, Sumiyama K, Matsuda M, Terai K. Visualization of Spatially-Controlled Vasospasm by Sympathetic Nerve-Mediated ROCK Activation. THE AMERICAN JOURNAL OF PATHOLOGY 2020; 191:194-203. [PMID: 33069718 DOI: 10.1016/j.ajpath.2020.09.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 09/06/2020] [Accepted: 09/23/2020] [Indexed: 01/30/2023]
Abstract
Contraction of vascular smooth muscle is regulated primarily by calcium concentration and secondarily by ROCK activity within the cells. In contrast to the wealth of information regarding regulation of calcium concentration, little is known about the spatiotemporal regulation of ROCK activity in live blood vessels. Here, we report ROCK activation in subcutaneous arterioles in a transgenic mouse line that expresses a genetically encoded ROCK biosensor based on the principle of Fӧrster resonance energy transfer by two-photon excitation in vivo imaging. Rapid vasospasm was induced upon laser ablation of arterioles, concomitant with a transient increase in calcium concentration in arteriolar smooth muscles. Unlike the increase in calcium concentration, vasoconstriction and ROCK activation continued for several minutes after irradiation. Both the ROCK inhibitor, fasudil, and the ganglionic nicotinic acetylcholine receptor blocker, hexamethonium, inhibited laser-induced ROCK activation and reduced the duration of vasospasm at the segments distant from the irradiated point. These observations suggest that vasoconstriction is initially triggered by a rapid surge of cytoplasmic calcium and then maintained by sympathetic nerve-mediated ROCK activation.
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Affiliation(s)
- Ayako Imanishi
- Laboratory of Bioimaging and Cell Signaling, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Hiroshi Ichise
- Laboratory of Bioimaging and Cell Signaling, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Chuyun Fan
- Laboratory of Bioimaging and Cell Signaling, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Yasuaki Nakagawa
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Koichiro Kuwahara
- Department of Cardiovascular Medicine, Shinshu University School of Medicine, Nagano, Japan
| | - Kenta Sumiyama
- Laboratory for Mouse Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Osaka, Japan
| | - Michiyuki Matsuda
- Laboratory of Bioimaging and Cell Signaling, Graduate School of Biostudies, Kyoto University, Kyoto, Japan; Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Kenta Terai
- Laboratory of Bioimaging and Cell Signaling, Graduate School of Biostudies, Kyoto University, Kyoto, Japan.
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230
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Yang T, Zhang F. Targeting Transcription Factor Nrf2 (Nuclear Factor Erythroid 2-Related Factor 2) for the Intervention of Vascular Cognitive Impairment and Dementia. Arterioscler Thromb Vasc Biol 2020; 41:97-116. [PMID: 33054394 DOI: 10.1161/atvbaha.120.314804] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Vascular cognitive impairment and dementia (VCID) is an age-related, mild to severe mental disability due to a broad panel of cerebrovascular disorders. Its pathobiology involves neurovascular dysfunction, blood-brain barrier disruption, white matter damage, microRNAs, oxidative stress, neuroinflammation, and gut microbiota alterations, etc. Nrf2 (Nuclear factor erythroid 2-related factor 2) is the master regulator of redox status and controls the transcription of a panel of antioxidative and anti-inflammatory genes. By interacting with NF-κB (nuclear factor-κB), Nrf2 also fine-tunes the cellular oxidative and inflammatory balance. Aging is associated with Nrf2 dysfunction, and increasing evidence has proved the role of Nrf2 in mitigating the VCID process. Based on VCID pathobiologies and Nrf2 studies from VCID and other brain diseases, we point out several hypothetical Nrf2 targets for VCID management, including restoration of endothelial function and neurovascular coupling, preservation of blood-brain barrier integrity, reduction of amyloidopathy, promoting white matter integrity, and mitigating oxidative stress and neuroinflammation. Collectively, the Nrf2 pathway could be a promising direction for future VCID research. Targeting Nrf2 would shed light on VCID managing strategies.
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Affiliation(s)
- Tuo Yang
- Department of Neurology, Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh, PA
| | - Feng Zhang
- Department of Neurology, Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh, PA
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231
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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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232
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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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233
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The cells involved in the pathological process of diabetic retinopathy. Biomed Pharmacother 2020; 132:110818. [PMID: 33053509 DOI: 10.1016/j.biopha.2020.110818] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 09/20/2020] [Accepted: 09/25/2020] [Indexed: 01/04/2023] Open
Abstract
Diabetic retinopathy(DR) is an expanding global health problem, the exact mechanism of which has not yet been clarified clearly, new insights into retinal physiology indicate that diabetes-induced retinal dysfunction may be viewed as an impairment of the retinal neurovascular unit, including retinal ganglion cells, glial cells, endothelial cells, pericytes, and retinal pigment epithelium. Different retinal cells have unique structure and functions, while the interactions among which are less known. Cells are the basic unit of organism structure and function, their impairment could lead to abnormal physiological functions and even organ disorder. Considering the body is multi-dimension and the complexity of DR, one point or a single type of cell can't be used to illustrate the mechanism of occurrence and development of DR. In this review, we provided a systematic and comprehensive elaboration of the cells that are involved in the process of DR. We underlined the importance of considering the neurovascular unit, not just retinal vascular and neural cells, in understanding the pathophysiology of DR. Our studies provided a better understanding of the pathological process in DR and provide a theoretical basis for further research.
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234
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Østergaard L. Blood flow, capillary transit times, and tissue oxygenation: the centennial of capillary recruitment. J Appl Physiol (1985) 2020; 129:1413-1421. [PMID: 33031017 DOI: 10.1152/japplphysiol.00537.2020] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The transport of oxygen between blood and tissue is limited by blood's capillary transit time, understood as the time available for diffusion exchange before blood returns to the heart. If all capillaries contribute equally to tissue oxygenation at all times, this physical limitation would render vasodilation and increased blood flow insufficient means to meet increased metabolic demands in the heart, muscle, and other organs. In 1920, Danish physiologist August Krogh was awarded the Nobel Prize in Physiology or Medicine for his mathematical and quantitative, experimental demonstration of a solution to this conceptual problem: capillary recruitment, the active opening of previously closed capillaries to meet metabolic demands. Today, capillary recruitment is still mentioned in textbooks. When we suspect symptoms might represent hypoxia of a vascular origin, however, we search for relevant, flow-limiting conditions in our patients and rarely ascribe hypoxia or hypoxemia to short capillary transit times. This review describes how natural changes in capillary transit-time heterogeneity (CTH) and capillary hematocrit (HCT) across open capillaries during blood flow increases can account for a match of oxygen availability to metabolic demands in normal tissue. CTH and HCT depend on a number of factors: on blood properties, including plasma viscosity, the number, size, and deformability of blood cells, and blood cell interactions with capillary endothelium; on anatomical factors including glycocalyx, endothelial cells, basement membrane, and pericytes that affect the capillary diameter; and on any external compression. The review describes how risk factor- and disease-related changes in CTH and HCT interfere with flow-metabolism coupling and tissue oxygenation and discusses whether such capillary dysfunction contributes to vascular disease pathology.
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Affiliation(s)
- Leif Østergaard
- Center of Functionally Integrative Neuroscience, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Neuroradiology Research Unit, Section of Neuroradiology, Department of Radiology, Aarhus University Hospital, Aarhus, Denmark
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235
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Echagarruga CT, Gheres KW, Norwood JN, Drew PJ. nNOS-expressing interneurons control basal and behaviorally evoked arterial dilation in somatosensory cortex of mice. eLife 2020; 9:e60533. [PMID: 33016877 PMCID: PMC7556878 DOI: 10.7554/elife.60533] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 10/02/2020] [Indexed: 12/19/2022] Open
Abstract
Cortical neural activity is coupled to local arterial diameter and blood flow. However, which neurons control the dynamics of cerebral arteries is not well understood. We dissected the cellular mechanisms controlling the basal diameter and evoked dilation in cortical arteries in awake, head-fixed mice. Locomotion drove robust arterial dilation, increases in gamma band power in the local field potential (LFP), and increases calcium signals in pyramidal and neuronal nitric oxide synthase (nNOS)-expressing neurons. Chemogenetic or pharmocological modulation of overall neural activity up or down caused corresponding increases or decreases in basal arterial diameter. Modulation of pyramidal neuron activity alone had little effect on basal or evoked arterial dilation, despite pronounced changes in the LFP. Modulation of the activity of nNOS-expressing neurons drove changes in the basal and evoked arterial diameter without corresponding changes in population neural activity.
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Affiliation(s)
| | - Kyle W Gheres
- Molecular, Cellular, and Integrative Biology Graduate Program, Pennsylvania State UniversityUniversity ParkUnited States
| | - Jordan N Norwood
- Cell and Developmental Biology Graduate Program, Pennsylvania State UniversityUniversity ParkUnited States
| | - Patrick J Drew
- Bioengineering Graduate Program, Pennsylvania State UniversityUniversity ParkUnited States
- Molecular, Cellular, and Integrative Biology Graduate Program, Pennsylvania State UniversityUniversity ParkUnited States
- Cell and Developmental Biology Graduate Program, Pennsylvania State UniversityUniversity ParkUnited States
- Departments of Engineering Science and Mechanics, Biomedical Engineering, and Neurosurgery, Pennsylvania State UniversityUniversity ParkUnited States
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236
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Quelhas P, Baltazar G, Cairrao E. The Neurovascular Unit: Focus on the Regulation of Arterial Smooth Muscle Cells. Curr Neurovasc Res 2020; 16:502-515. [PMID: 31738142 DOI: 10.2174/1567202616666191026122642] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 09/01/2019] [Accepted: 09/20/2019] [Indexed: 02/08/2023]
Abstract
The neurovascular unit is a physiological unit present in the brain, which is constituted by elements of the nervous system (neurons and astrocytes) and the vascular system (endothelial and mural cells). This unit is responsible for the homeostasis and regulation of cerebral blood flow. There are two major types of mural cells in the brain, pericytes and smooth muscle cells. At the arterial level, smooth muscle cells are the main components that wrap around the outside of cerebral blood vessels and the major contributors to basal tone maintenance, blood pressure and blood flow distribution. They present several mechanisms by which they regulate both vasodilation and vasoconstriction of cerebral blood vessels and their regulation becomes even more important in situations of injury or pathology. In this review, we discuss the main regulatory mechanisms of brain smooth muscle cells and their contributions to the correct brain homeostasis.
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Affiliation(s)
- Patrícia Quelhas
- CICS-UBI - Centro de Investigacao em Ciencias da Saude, University of Beira Interior, 6200-506 Covilha, Portugal
| | - Graça Baltazar
- CICS-UBI - Centro de Investigacao em Ciencias da Saude, University of Beira Interior, 6200-506 Covilha, Portugal
| | - Elisa Cairrao
- CICS-UBI - Centro de Investigacao em Ciencias da Saude, University of Beira Interior, 6200-506 Covilha, Portugal
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237
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Tran CHT, George AG, Teskey GC, Gordon GR. Seizures elevate gliovascular unit Ca2+ and cause sustained vasoconstriction. JCI Insight 2020; 5:136469. [PMID: 33004688 PMCID: PMC7566700 DOI: 10.1172/jci.insight.136469] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 08/20/2020] [Indexed: 12/31/2022] Open
Abstract
Seizures can result in a severe hypoperfusion/hypoxic attack that causes postictal memory and behavioral impairments. However, neither postictal changes to microvasculature nor Ca2+ changes in key cell types controlling blood perfusion have been visualized in vivo, leaving essential components of the underlying cellular mechanisms unclear. Here, we use 2-photon microvascular and Ca2+ imaging in awake mice to show that seizures result in a robust vasoconstriction of cortical penetrating arterioles, which temporally mirrors the prolonged postictal hypoxia. The vascular effect was dependent on cyclooxygenase 2, as pretreatment with ibuprofen prevented postictal vasoconstriction. Moreover, seizures caused a rapid elevation in astrocyte endfoot Ca2+ that was confined to the seizure period, and vascular smooth muscle cells displayed a significant increase in Ca2+ both during and following seizures, lasting up to 75 minutes. Our data show enduring postictal vasoconstriction and temporal activities of 2 cell types within the neurovascular unit that are associated with seizure-induced hypoperfusion/hypoxia. These findings support prevention of this event may be a novel and tractable treatment strategy in patients with epilepsy who experience extended postseizure impairments. Seizures cause enduring microvascular constriction via long lasting calcium elevations in vascular smooth muscle cells.
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Affiliation(s)
- Cam Ha T Tran
- Hotchkiss Brain Institute and.,Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
| | - Antis G George
- Hotchkiss Brain Institute and.,Department of Cell Biology and Anatomy, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - G Campbell Teskey
- Hotchkiss Brain Institute and.,Department of Cell Biology and Anatomy, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Grant R Gordon
- Hotchkiss Brain Institute and.,Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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238
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Anfray A, Drieu A, Hingot V, Hommet Y, Yetim M, Rubio M, Deffieux T, Tanter M, Orset C, Vivien D. Circulating tPA contributes to neurovascular coupling by a mechanism involving the endothelial NMDA receptors. J Cereb Blood Flow Metab 2020; 40:2038-2054. [PMID: 31665952 PMCID: PMC7786842 DOI: 10.1177/0271678x19883599] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The increase of cerebral blood flow evoked by neuronal activity is essential to ensure enough energy supply to the brain. In the neurovascular unit, endothelial cells are ideally placed to regulate key neurovascular functions of the brain. Nevertheless, some outstanding questions remain about their exact role neurovascular coupling (NVC). Here, we postulated that the tissue-type plasminogen activator (tPA) present in the circulation might contribute to NVC by a mechanism dependent of its interaction with endothelial N-Methyl-D-Aspartate Receptor (NMDAR). To address this question, we used pharmacological and genetic approaches to interfere with vascular tPA-dependent NMDAR signaling, combined with laser speckle flowmetry, intravital microscopy and ultrafast functional ultrasound in vivo imaging. We found that the tPA present in the blood circulation is capable of potentiating the cerebral blood flow increase induced by the activation of the mouse somatosensorial cortex, and that this effect is mediated by a tPA-dependent activation of NMDAR expressed at the luminal part of endothelial cells of arteries. Although blood molecules, such as acetylcholine, bradykinin or ATP are known to regulate vascular tone and induce vessel dilation, our present data provide the first evidence that circulating tPA is capable of influencing neurovascular coupling (NVC).
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Affiliation(s)
- Antoine Anfray
- Normandie University, UNICAEN, INSERM, UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), GIP Cyceron, Caen, France
| | - Antoine Drieu
- Normandie University, UNICAEN, INSERM, UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), GIP Cyceron, Caen, France
| | - Vincent Hingot
- Institut Langevin, CNRS, INSERM, ESPCI Paris, PSL Research University, Paris, France
| | - Yannick Hommet
- Normandie University, UNICAEN, INSERM, UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), GIP Cyceron, Caen, France
| | - Mervé Yetim
- Normandie University, UNICAEN, INSERM, UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), GIP Cyceron, Caen, France
| | - Marina Rubio
- Normandie University, UNICAEN, INSERM, UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), GIP Cyceron, Caen, France
| | - Thomas Deffieux
- Institut Langevin, CNRS, INSERM, ESPCI Paris, PSL Research University, Paris, France
| | - Mickael Tanter
- Institut Langevin, CNRS, INSERM, ESPCI Paris, PSL Research University, Paris, France
| | - Cyrille Orset
- Normandie University, UNICAEN, INSERM, UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), GIP Cyceron, Caen, France
| | - Denis Vivien
- Normandie University, UNICAEN, INSERM, UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), GIP Cyceron, Caen, France
- CHU Caen, Department of Clinical Research, Caen Normandie University Hospital, Avenue de la Côte de Nacre, Caen, France
- Denis Vivien, INSERM UMR-S U1237 “Physiopathology and Imaging of Neurological Disorders”, University Caen Normandie, GIP Cyceron, Bd Becquerel, BP5229, Caen 14074, France.
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239
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Kureli G, Yilmaz-Ozcan S, Erdener SE, Donmez-Demir B, Yemisci M, Karatas H, Dalkara T. F-actin polymerization contributes to pericyte contractility in retinal capillaries. Exp Neurol 2020; 332:113392. [DOI: 10.1016/j.expneurol.2020.113392] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/15/2020] [Accepted: 06/25/2020] [Indexed: 01/24/2023]
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240
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Quelhas P, Baltazar G, Cairrao E. Characterization of culture from smooth muscle cells isolated from rat middle cerebral arteries. Tissue Cell 2020; 66:101400. [PMID: 32933705 DOI: 10.1016/j.tice.2020.101400] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 06/09/2020] [Accepted: 06/26/2020] [Indexed: 02/07/2023]
Abstract
Although human brain represents only 2% of the body mass, it uses around 20 % of the organism energy. Due to the brain's limited energy storage, the oxygen and glucose necessary to support brain functions depends on the correct blood supply. The main components of the arteries are smooth muscle cells, which are considered the main regulators of vascular tone and blood flow distribution. The information currently available on the functioning of the cerebral arteries and their cell constituents is extremely scarce. Thus, the aim of this work was to develop an in vitro model of smooth muscle cells derived from rat middle cerebral artery. Explants were collected from rat middle cerebral artery and adhered to collagen-coated culture dishes. Immunocytochemical analysis showed that the cells present in the culture expressed α-actin, a protein characteristic of the contractile phenotype of these cells. In addition, these cells did not express the endothelial marker, vWF. To evaluate the functionality of these cells the response to contractile agents, serotonin and noradrenaline, and to relaxing agent, sodium nitroprusside was determine by Planar Cell Surface Area analysis. Together the data obtained show that the cell culture obtained through the procedure described resulted in cells presenting the markers characteristic of smooth muscle cells and maintaining the usual contractile response, indicating that the cells obtained through this may be used as a model for characterization and study of functional behavior of the middle cerebral artery, as well as interaction studies between vascular and neuronal system.
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Affiliation(s)
- Patricia Quelhas
- CICS-UBI - Centro de Investigação em Ciências da Saúde, University of Beira Interior, 6200-506 Covilhã, Portugal
| | - Graça Baltazar
- CICS-UBI - Centro de Investigação em Ciências da Saúde, University of Beira Interior, 6200-506 Covilhã, Portugal
| | - Elisa Cairrao
- CICS-UBI - Centro de Investigação em Ciências da Saúde, University of Beira Interior, 6200-506 Covilhã, Portugal.
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241
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Mantegazza A, Ungari M, Clavica F, Obrist D. Local vs. Global Blood Flow Modulation in Artificial Microvascular Networks: Effects on Red Blood Cell Distribution and Partitioning. Front Physiol 2020; 11:566273. [PMID: 33123027 PMCID: PMC7571285 DOI: 10.3389/fphys.2020.566273] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 08/12/2020] [Indexed: 12/12/2022] Open
Abstract
Our understanding of cerebral blood flow (CBF) regulation during functional activation is still limited. Alongside with the accepted role of smooth muscle cells in controlling the arteriolar diameter, a new hypothesis has been recently formulated suggesting that CBF may be modulated by capillary diameter changes mediated by pericytes. In this study, we developed in vitro microvascular network models featuring a valve enabling the dilation of a specific micro-channel. This allowed us to investigate the non-uniform red blood cell (RBC) partitioning at microvascular bifurcations (phase separation) and the hematocrit distribution at rest and for two scenarios modeling capillary and arteriolar dilation. RBC partitioning showed similar phase separation behavior during baseline and activation. Results indicated that the RBCs at diverging bifurcations generally enter the high-flow branch (classical partitioning). Inverse behavior (reverse partitioning) was observed for skewed hematocrit profiles in the parent vessel of bifurcations, especially for high RBC velocity (i.e., arteriolar activation). Moreover, results revealed that a local capillary dilation, as it may be mediated in vivo by pericytes, led to a localized increase of RBC flow and a heterogeneous hematocrit redistribution within the whole network. In case of a global increase of the blood flow, as it may be achieved by dilating an arteriole, a homogeneous increase of RBC flow was observed in the whole network and the RBCs were concentrated along preferential pathways. In conclusion, overall increase of RBC flow could be obtained by arteriolar and capillary dilation, but only capillary dilation was found to alter the perfusion locally and heterogeneously.
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Affiliation(s)
- Alberto Mantegazza
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Matteo Ungari
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Francesco Clavica
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland.,Integrated Actuators Laboratory, École Polytechnique Fédérale de Lausanne, Neuchâtel, Switzerland
| | - Dominik Obrist
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
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242
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Chan ST, Evans KC, Song TY, Selb J, van der Kouwe A, Rosen BR, Zheng YP, Ahn AC, Kwong KK. Dynamic brain-body coupling of breath-by-breath O2-CO2 exchange ratio with resting state cerebral hemodynamic fluctuations. PLoS One 2020; 15:e0238946. [PMID: 32956397 PMCID: PMC7505589 DOI: 10.1371/journal.pone.0238946] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 08/26/2020] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND The origin of low frequency cerebral hemodynamic fluctuations (CHF) in the resting state remains unknown. Breath-by breath O2-CO2 exchange ratio (bER) has been reported to correlate with the cerebrovascular response to brief breath hold challenge at the frequency range of 0.008-0.03Hz in healthy adults. bER is defined as the ratio of the change in the partial pressure of oxygen (ΔPO2) to that of carbon dioxide (ΔPCO2) between end inspiration and end expiration. In this study, we aimed to investigate the contribution of respiratory gas exchange (RGE) metrics (bER, ΔPO2 and ΔPCO2) to low frequency CHF during spontaneous breathing. METHODS Twenty-two healthy adults were included. We used transcranial Doppler sonography to evaluate CHF by measuring the changes in cerebral blood flow velocity (ΔCBFv) in bilateral middle cerebral arteries. The regional CHF were mapped with blood oxygenation level dependent (ΔBOLD) signal changes using functional magnetic resonance imaging. Temporal features and frequency characteristics of RGE metrics during spontaneous breathing were examined, and the simultaneous measurements of RGE metrics and CHF (ΔCBFv and ΔBOLD) were studied for their correlation. RESULTS We found that the time courses of ΔPO2 and ΔPCO2 were interdependent but not redundant. The oscillations of RGE metrics were coherent with resting state CHF at the frequency range of 0.008-0.03Hz. Both bER and ΔPO2 were superior to ΔPCO2 in association with CHF while CHF could correlate more strongly with bER than with ΔPO2 in some brain regions. Brain regions with the strongest coupling between bER and ΔBOLD overlapped with many areas of default mode network including precuneus and posterior cingulate. CONCLUSION Although the physiological mechanisms underlying the strong correlation between bER and CHF are unclear, our findings suggest the contribution of bER to low frequency resting state CHF, providing a novel insight of brain-body interaction via CHF and oscillations of RGE metrics.
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Affiliation(s)
- Suk-tak Chan
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Karleyton C. Evans
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Tian-yue Song
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Juliette Selb
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Andre van der Kouwe
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Bruce R. Rosen
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Yong-ping Zheng
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong Special Administrative Region, China
| | - Andrew C. Ahn
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Kenneth K. Kwong
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
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243
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Poole DC, Pittman RN, Musch TI, Østergaard L. August Krogh's theory of muscle microvascular control and oxygen delivery: a paradigm shift based on new data. J Physiol 2020; 598:4473-4507. [PMID: 32918749 DOI: 10.1113/jp279223] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 07/13/2020] [Indexed: 12/16/2022] Open
Abstract
August Krogh twice won the prestigious international Steegen Prize, for nitrogen metabolism (1906) and overturning the concept of active transport of gases across the pulmonary epithelium (1910). Despite this, at the beginning of 1920, the consummate experimentalist was relatively unknown worldwide and even among his own University of Copenhagen faculty. But, in early 1919, he had submitted three papers to Dr Langley, then editor of The Journal of Physiology in England. These papers coalesced anatomical observations of skeletal muscle capillary numbers with O2 diffusion theory to propose a novel active role for capillaries that explained the prodigious increase in blood-muscle O2 flux from rest to exercise. Despite his own appraisal of the first two papers as "rather dull" to his friend, the eminent Cambridge respiratory physiologist, Joseph Barcroft, Krogh believed that the third one, dealing with O2 supply and capillary regulation, was"interesting". These papers, which won Krogh an unopposed Nobel Prize for Physiology or Medicine in 1920, form the foundation for this review. They single-handedly transformed the role of capillaries from passive conduit and exchange vessels, functioning at the mercy of their upstream arterioles, into independent contractile units that were predominantly closed at rest and opened actively during muscle contractions in a process he termed 'capillary recruitment'. Herein we examine Krogh's findings and some of the experimental difficulties he faced. In particular, the boundary conditions selected for his model (e.g. heavily anaesthetized animals, negligible intramyocyte O2 partial pressure, binary open-closed capillary function) have not withstood the test of time. Subsequently, we update the reader with intervening discoveries that underpin our current understanding of muscle microcirculatory control and place a retrospectroscope on Krogh's discoveries. The perspective is presented that the imprimatur of the Nobel Prize, in this instance, may have led scientists to discount compelling evidence. Much as he and Marie Krogh demonstrated that active transport of gases across the blood-gas barrier was unnecessary in the lung, capillaries in skeletal muscle do not open and close spontaneously or actively, nor is this necessary to account for the increase in blood-muscle O2 flux during exercise. Thus, a contemporary model of capillary function features most muscle capillaries supporting blood flow at rest, and, rather than capillaries actively vasodilating from rest to exercise, increased blood-myocyte O2 flux occurs predominantly via elevating red blood cell and plasma flux in already flowing capillaries. Krogh is lauded for his brilliance as an experimentalist and for raising scientific questions that led to fertile avenues of investigation, including the study of microvascular function.
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Affiliation(s)
- David C Poole
- Departments of Kinesiology and Anatomy and Physiology, Kansas State University Manhattan, Manhattan, KS, 66506, USA
| | - Roland N Pittman
- Department of Physiology and Biophysics, Virginia Commonwealth University Richmond, Richmond, VA, 23298-0551, USA
| | - Timothy I Musch
- Departments of Kinesiology and Anatomy and Physiology, Kansas State University Manhattan, Manhattan, KS, 66506, USA
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience, Aarhus University, Denmark
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244
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Ivanova E, Corona C, Eleftheriou CG, Bianchimano P, Sagdullaev BT. Retina-specific targeting of pericytes reveals structural diversity and enables control of capillary blood flow. J Comp Neurol 2020; 529:1121-1134. [PMID: 32812219 DOI: 10.1002/cne.25011] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/11/2020] [Accepted: 08/12/2020] [Indexed: 12/14/2022]
Abstract
Pericytes are a unique class of mural cells essential for angiogenesis, maintenance of the vasculature and are key players in microvascular pathology. However, their diversity and specific roles are poorly understood, limiting our insight into vascular physiology and the ability to develop effective therapies. Here, in the mouse retina, a tractable model of the CNS, we evaluated distinct classes of mural cells along the vascular tree for both structural characterization and physiological manipulation of blood flow. To accomplish this, we first tested three inducible mural cell-specific mouse lines using a sensitive Ai14 reporter and tamoxifen application either by a systemic injection, or by local administration in the form of eye drops. The specificity and pattern of cre activation varied significantly across the three lines, under either the PDGFRβ or NG2 promoter (Pdgfrβ-CreRha, Pdgfrβ-CreCsln, and Cspg4-Cre). In particular, a mouse line with Cre under the NG2 promoter resulted in sparse TdTomato labeling of mural cells, allowing for an unambiguous characterization of anatomical features of individual sphincter cells and capillary pericytes. Furthermore, in one PDGFRβ line, we found that focal eye drop application of tamoxifen led to an exclusive Cre-activation in pericytes, without affecting arterial mural cells. We then used this approach to boost capillary blood flow by selective expression of Halorhodopsin, a highly precise hyperpolarizing optogenetic actuator. The ability to exclusively target capillary pericytes may prove a precise and potentially powerful tool to treat microcirculation deficits, a common pathology in numerous diseases.
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Affiliation(s)
- Elena Ivanova
- Burke Neurological Institute, White Plains, New York, USA.,Department of Ophthalmology, BMRI, Weill Cornell Medicine, New York, New York, USA
| | - Carlo Corona
- Burke Neurological Institute, White Plains, New York, USA
| | | | | | - Botir T Sagdullaev
- Burke Neurological Institute, White Plains, New York, USA.,Department of Ophthalmology, BMRI, Weill Cornell Medicine, New York, New York, USA
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245
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Mitsui R, Hashitani H. Synchrony of spontaneous Ca 2+ activity in microvascular mural cells. J Smooth Muscle Res 2020; 56:1-18. [PMID: 32249242 PMCID: PMC7132055 DOI: 10.1540/jsmr.56.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Spontaneous rhythmic constrictions known as vasomotion are developed in several microvascular beds in vivo. Vasomotion in arterioles is considered to facilitate blood flow, while venular vasomotion would facilitate tissue metabolite drainage. Mechanisms underlying vasomotion periodically generate synchronous Ca2+ transients in vascular smooth muscle cells (VSMCs). In visceral organs, mural cells (pericytes and VSMCs) in arterioles, capillaries and venules exhibit synchronous spontaneous Ca2+ transients. Since sympathetic regulation is rather limited in the intra-organ microvessels, spontaneous activity of mural cells may play an essential role in maintaining tissue perfusion. Synchronous spontaneous Ca2+ transients in precapillary arterioles (PCAs)/capillaries appear to propagate to upstream arterioles to drive their vasomotion, while venules develop their own synchronous Ca2+ transients and associated vasomotion. Spontaneous Ca2+ transients of mural cells primarily arise from IP3 and/or ryanodine receptor-mediated Ca2+ release from sarcoendoplasmic reticulum (SR/ER) Ca2+ stores. The resultant opening of Ca2+-activated Cl- channels (CaCCs) causes a membrane depolarisation that triggers Ca2+ influx via T-type and/or L-type voltage-dependent Ca2+ channels (VDCCs). Mural cells are electrically coupled with each other via gap junctions, and thus allow the sequential spread of CaCC or VDCC-dependent depolarisations to develop the synchrony of Ca2+ transients within their network. Importantly, the synchrony of spontaneous Ca2+ transients also requires a certain range of the resting membrane potential that is maintained by the opening of Kv7 voltage-dependent K+ (Kv7) and inward rectifier K+ (Kir) channels. Thus, a depolarised membrane would evoke asynchronous, 'premature' spontaneous Ca2+ transients, while a hyperpolarised membrane prevents any spontaneous activity.
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Affiliation(s)
- Retsu Mitsui
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan
| | - Hikaru Hashitani
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan
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246
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Regeneration of the neurogliovascular unit visualized in vivo by transcranial live-cell imaging. J Neurosci Methods 2020; 343:108808. [DOI: 10.1016/j.jneumeth.2020.108808] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 06/02/2020] [Accepted: 06/11/2020] [Indexed: 12/15/2022]
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247
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Kedarasetti RT, Turner KL, Echagarruga C, Gluckman BJ, Drew PJ, Costanzo F. Functional hyperemia drives fluid exchange in the paravascular space. Fluids Barriers CNS 2020; 17:52. [PMID: 32819402 PMCID: PMC7441569 DOI: 10.1186/s12987-020-00214-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 08/09/2020] [Indexed: 12/20/2022] Open
Abstract
The brain lacks a conventional lymphatic system to remove metabolic waste. It has been proposed that directional fluid movement through the arteriolar paravascular space (PVS) promotes metabolite clearance. We performed simulations to examine if arteriolar pulsations and dilations can drive directional CSF flow in the PVS and found that arteriolar wall movements do not drive directional CSF flow. We propose an alternative method of metabolite clearance from the PVS, namely fluid exchange between the PVS and the subarachnoid space (SAS). In simulations with compliant brain tissue, arteriolar pulsations did not drive appreciable fluid exchange between the PVS and the SAS. However, when the arteriole dilated, as seen during functional hyperemia, there was a marked exchange of fluid. Simulations suggest that functional hyperemia may serve to increase metabolite clearance from the PVS. We measured blood vessels and brain tissue displacement simultaneously in awake, head-fixed mice using two-photon microscopy. These measurements showed that brain deforms in response to pressure changes in PVS, consistent with our simulations. Our results show that the deformability of the brain tissue needs to be accounted for when studying fluid flow and metabolite transport.
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Affiliation(s)
- Ravi Teja Kedarasetti
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA
| | - Kevin L Turner
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Christina Echagarruga
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Bruce J Gluckman
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA
- Department of Neurosurgery, The Pennsylvania State University, University Park, PA, USA
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Patrick J Drew
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA.
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA.
- Department of Neurosurgery, The Pennsylvania State University, University Park, PA, USA.
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA.
| | - Francesco Costanzo
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA.
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA.
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA.
- Department of Mathematics, The Pennsylvania State University, University Park, PA, USA.
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248
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Bhattacharya A, Kaushik DK, Lozinski BM, Yong VW. Beyond barrier functions: Roles of pericytes in homeostasis and regulation of neuroinflammation. J Neurosci Res 2020; 98:2390-2405. [PMID: 32815569 DOI: 10.1002/jnr.24715] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 06/22/2020] [Accepted: 07/28/2020] [Indexed: 12/19/2022]
Abstract
Pericytes are contractile cells that extend along the vasculature to mediate key homeostatic functions of endothelial barriers within the body. In the central nervous system (CNS), pericytes are important contributors to the structure and function of the neurovascular unit, which includes endothelial cells, astrocytes and neurons. The understanding of pericytes has been marred by an inability to accurately distinguish pericytes from other stromal cells with similar expression of identifying markers. Evidence is now growing in favor of pericytes being actively involved in both CNS homeostasis and pathology of neurological diseases, including multiple sclerosis, spinal cord injury, and Alzheimer's disease among others. In this review, we discuss the current understanding on the characterization of pericytes, their roles in maintaining the integrity of the blood-brain barrier, and their contributions to neuroinflammation and neurorepair. Owing to its plethora of surface receptors, pericytes respond to inflammatory mediators such as CCL2 (monocyte chemoattractant protein-1) and tumor necrosis factor-α, in turn secreting CCL2, nitric oxide, and several cytokines. Pericytes can therefore act as promoters of both the innate and adaptive arms of the immune system. Much like professional phagocytes, pericytes also have the ability to clear up cellular debris and macromolecular plaques. Moreover, pericytes promote the activities of CNS glia, including in maturation of oligodendrocyte lineage cells for myelination. Conversely, pericytes can impair regenerative processes by contributing to scar formation. A better characterization of CNS pericytes and their functions would bode well for therapeutics aimed at alleviating their undesirable properties and enhancing their benefits.
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Affiliation(s)
- Anindita Bhattacharya
- Department of Clinical Neurosciences, Hotchkiss Brain institute, University of Calgary, Calgary, AB, Canada
| | - Deepak Kumar Kaushik
- Department of Clinical Neurosciences, Hotchkiss Brain institute, University of Calgary, Calgary, AB, Canada
| | - Brian Mark Lozinski
- Department of Clinical Neurosciences, Hotchkiss Brain institute, University of Calgary, Calgary, AB, Canada
| | - V Wee Yong
- Department of Clinical Neurosciences, Hotchkiss Brain institute, University of Calgary, Calgary, AB, Canada
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249
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Freitas-Andrade M, Raman-Nair J, Lacoste B. Structural and Functional Remodeling of the Brain Vasculature Following Stroke. Front Physiol 2020; 11:948. [PMID: 32848875 PMCID: PMC7433746 DOI: 10.3389/fphys.2020.00948] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 07/14/2020] [Indexed: 12/12/2022] Open
Abstract
Maintenance of cerebral blood vessel integrity and regulation of cerebral blood flow ensure proper brain function. The adult human brain represents only a small portion of the body mass, yet about a quarter of the cardiac output is dedicated to energy consumption by brain cells at rest. Due to a low capacity to store energy, brain health is heavily reliant on a steady supply of oxygen and nutrients from the bloodstream, and is thus particularly vulnerable to stroke. Stroke is a leading cause of disability and mortality worldwide. By transiently or permanently limiting tissue perfusion, stroke alters vascular integrity and function, compromising brain homeostasis and leading to widespread consequences from early-onset motor deficits to long-term cognitive decline. While numerous lines of investigation have been undertaken to develop new pharmacological therapies for stroke, only few advances have been made and most clinical trials have failed. Overall, our understanding of the acute and chronic vascular responses to stroke is insufficient, yet a better comprehension of cerebrovascular remodeling following stroke is an essential prerequisite for developing novel therapeutic options. In this review, we present a comprehensive update on post-stroke cerebrovascular remodeling, an important and growing field in neuroscience, by discussing cellular and molecular mechanisms involved, sex differences, limitations of preclinical research design and future directions.
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Affiliation(s)
| | - Joanna Raman-Nair
- Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Baptiste Lacoste
- Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
- Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada
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250
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Braun M, Iliff JJ. The impact of neurovascular, blood-brain barrier, and glymphatic dysfunction in neurodegenerative and metabolic diseases. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2020; 154:413-436. [PMID: 32739013 DOI: 10.1016/bs.irn.2020.02.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The cerebral vasculature serves as the crossroads of the CNS, supporting exchange of nutrients, metabolic wastes, solutes and cells between the compartments of the brain, including the blood, brain interstitium, and cerebrospinal fluid (CSF). The blood-brain barrier (BBB) regulates the entry and efflux of molecules into brain tissue. The cells of the neurovascular unit regulate cerebral blood flow, matching local metabolic demand to blood supply. The blood-CSF barrier at the choroid plexus secretes CSF, which supports the brain and provides a sink for interstitial solutes not cleared across the BBB. Recent studies have characterized the glymphatic system, a brain-wide network of perivascular spaces that supports CSF and interstitial fluid exchange and the clearance of interstitial solutes to the CSF. The critical role that these structures play in maintaining brain homeostasis is illustrated by the established and emerging roles that their dysfunctions play in the development of neurodegenerative diseases, such as Alzheimer's disease (AD). Loss of BBB and blood-CSF barrier function is reported both in rodent models of AD, and in human AD subjects. Cerebrovascular dysfunction and ischemic injury are well established contributors to both vascular dementia and to a large proportion of cases of sporadic AD. In animal models, the slowed glymphatic clearance of interstitial proteins, such as amyloid β or tau, are proposed to contribute to the development of neurodegenerative diseases, including AD. In total, these findings suggest that cellular and molecular changes occurring within and around the cerebral vasculature are among the key drivers of neurodegenerative disease pathogenesis.
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Affiliation(s)
- Molly Braun
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA, United States; VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), VA Puget Sound Health Care System, Seattle, WA, United States
| | - Jeffrey J Iliff
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA, United States; VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), VA Puget Sound Health Care System, Seattle, WA, United States; Department of Neurology, University of Washington School of Medicine, Seattle, WA, United States.
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