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Shuvalova M, Dmitrieva A, Belousov V, Nosov G. The role of reactive oxygen species in the regulation of the blood-brain barrier. Tissue Barriers 2024:2361202. [PMID: 38808582 DOI: 10.1080/21688370.2024.2361202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 05/23/2024] [Indexed: 05/30/2024] Open
Abstract
The blood-brain barrier (BBB) regulates the exchange of metabolites and cells between the blood and brain, and maintains central nervous system homeostasis. Various factors affect BBB barrier functions, including reactive oxygen species (ROS). ROS can act as stressors, damaging biological molecules, but they also serve as secondary messengers in intracellular signaling cascades during redox signaling. The impact of ROS on the BBB has been observed in multiple sclerosis, stroke, trauma, and other neurological disorders, making blocking ROS generation a promising therapeutic strategy for BBB dysfunction. However, it is important to consider ROS generation during normal BBB functioning for signaling purposes. This review summarizes data on proteins expressed by BBB cells that can be targets of redox signaling or oxidative stress. It also provides examples of signaling molecules whose impact may cause ROS generation in the BBB, as well as discusses the most common diseases associated with BBB dysfunction and excessive ROS generation, open questions that arise in the study of this problem, and possible ways to overcome them.
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Affiliation(s)
- Margarita Shuvalova
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, Moscow, Russia
- Department of metabolism and redox biology, Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Anastasiia Dmitrieva
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, Moscow, Russia
| | - Vsevolod Belousov
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, Moscow, Russia
- Department of metabolism and redox biology, Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
- Federal Center of Brain Research and Neurotechnologies, Federal Medical Biological Agency, Moscow, Russia
- Life Improvement by Future Technologies (LIFT) Center, Skolkovo, Moscow, Russia
| | - Georgii Nosov
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, Moscow, Russia
- Federal Center of Brain Research and Neurotechnologies, Federal Medical Biological Agency, Moscow, Russia
- Life Improvement by Future Technologies (LIFT) Center, Skolkovo, Moscow, Russia
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2
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Chen S, Guo D, Zhu Y, Xiao S, Xie J, Zhang Z, Hu Y, Huang J, Ma X, Ning Z, Cao L, Cheng J, Tang Y. Amyloid β oligomer induces cerebral vasculopathy via pericyte-mediated endothelial dysfunction. Alzheimers Res Ther 2024; 16:56. [PMID: 38475929 PMCID: PMC10935813 DOI: 10.1186/s13195-024-01423-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Accepted: 02/28/2024] [Indexed: 03/14/2024]
Abstract
BACKGROUND Although abnormal accumulation of amyloid beta (Aβ) protein is thought to be the main cause of Alzheimer's disease (AD), emerging evidence suggests a pivotal vascular contribution to AD. Aberrant amyloid β induces neurovascular dysfunction, leading to changes in the morphology and function of the microvasculature. However, little is known about the underlying mechanisms between Aβ deposition and vascular injuries. Recent studies have revealed that pericytes play a substantial role in the vasculopathy of AD. Additional research is imperative to attain a more comprehensive understanding. METHODS Two-photon microscopy and laser speckle imaging were used to examine cerebrovascular dysfunction. Aβ oligomer stereotactic injection model was established to explain the relationship between Aβ and vasculopathy. Immunofluorescence staining, western blot, and real-time PCR were applied to detect the morphological and molecular alternations of pericytes. Primary cultured pericytes and bEnd.3 cells were employed to explore the underlying mechanisms. RESULTS Vasculopathy including BBB damage, hypoperfusion, and low vessel density were found in the cortex of 8 to 10-month-old 5xFAD mice. A similar phenomenon accompanied by pericyte degeneration appeared in an Aβ-injected model, suggesting a direct relationship between Aβ and vascular dysfunction. Pericytes showed impaired features including low PDGFRβ expression and increased pro-inflammatory chemokines secretion under the administration of Aβ in vitro, of which supernatant cultured with bEND.3 cells led to significant endothelial dysfunction characterized by TJ protein deficiency. CONCLUSIONS Our results provide new insights into the pathogenic mechanism underlying Aβ-induced vasculopathy. Targeting pericyte therapies are promising to ameliorate vascular dysfunction in AD.
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Affiliation(s)
- Siqi Chen
- Department of Anesthesiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Daji Guo
- Department of Neurology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
- Nanhai Translational Innovation Center of Precision Immunology, Sun Yat-sen Memorial Hospital, Foshan, 528200, China
| | - Yuanyuan Zhu
- Department of Neurology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Songhua Xiao
- Department of Neurology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Jiatian Xie
- Department of Neurology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Zhan Zhang
- Department of Neurology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Yu Hu
- Department of Neurology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Jialin Huang
- Department of Neurology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Xueying Ma
- Department of Neurology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Zhiyuan Ning
- Department of Neurology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Lin Cao
- Department of Anesthesiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.
- Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat‑sen University, Guangzhou, 510120, China.
| | - Jinping Cheng
- Department of Neurology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.
- Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat‑sen University, Guangzhou, 510120, China.
- Nanhai Translational Innovation Center of Precision Immunology, Sun Yat-sen Memorial Hospital, Foshan, 528200, China.
| | - Yamei Tang
- Department of Neurology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.
- Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat‑sen University, Guangzhou, 510120, China.
- Nanhai Translational Innovation Center of Precision Immunology, Sun Yat-sen Memorial Hospital, Foshan, 528200, China.
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3
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Feng Y, Lau S, Chen Q, Oyston C, Groom K, Barrett CJ, Chamley LW. Normotensive placental extracellular vesicles provide long-term protection against hypertension and cardiovascular disease. Am J Obstet Gynecol 2023:S0002-9378(23)02189-0. [PMID: 38158074 DOI: 10.1016/j.ajog.2023.12.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 12/18/2023] [Accepted: 12/19/2023] [Indexed: 01/03/2024]
Abstract
BACKGROUND Women with normotensive pregnancy are at a reduced risk of developing cardiovascular disease postpartum compared with those who experience hypertensive conditions during pregnancy. However, the underlying mechanisms remain poorly understood. During normotensive pregnancy, vast numbers of placental extracellular vesicles are released into the maternal circulation, which protect endothelial cells from activation and alter maternal vascular tone. We hypothesized that placental extracellular vesicles play a mechanistic role in lowering the risk of cardiovascular disease following normotensive pregnancy. OBJECTIVE This study aimed to investigate the long-term effects of placental extracellular vesicles derived from normotensive term placentae on the cardiovascular system and explore the mechanisms underlying their biological effects. STUDY DESIGN Spontaneously hypertensive rats were injected with placental extracellular vesicles from normotensive term pregnancies (2 mg/kg each time, n=8) or vehicle control (n=9) at 3 months of age. Blood pressure and cardiac function were regularly monitored from 3 months to 15 months of age. The response of mesenteric resistance arteries to vasoactive substances was investigated to evaluate vascular function. Cardiac remodeling, small artery remodeling, and renal function were investigated to comprehensively assess the impact of placental extracellular vesicles on cardiovascular and renal health. RESULTS Compared with vehicle-treated control animals, rats treated with normotensive placental extracellular vesicles exhibited a significantly lower increase in blood pressure and improved cardiac function. Furthermore, the vasodilator response to the endothelium-dependent agonist acetylcholine was significantly enhanced in the normotensive placental extracellular vesicle-treated spontaneously hypertensive rats compared with the control. Moreover, treatment with placental extracellular vesicles reduced wall thickening of small renal vessels and attenuated renal fibrosis. CONCLUSION Placental extracellular vesicles from normotensive term pregnancies have long-lasting protective effects reducing hypertension and mitigating cardiovascular damage in vivo.
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Affiliation(s)
- Yourong Feng
- Department of Obstetrics and Gynaecology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.
| | - Sandy Lau
- Department of Obstetrics and Gynaecology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Qi Chen
- Department of Obstetrics and Gynaecology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Charlotte Oyston
- Department of Obstetrics and Gynaecology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Katie Groom
- Liggins Institute, The University of Auckland, Auckland, New Zealand
| | - Carolyn J Barrett
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Lawrence W Chamley
- Department of Obstetrics and Gynaecology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
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4
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Whitehead B, Karelina K, Weil ZM. Pericyte dysfunction is a key mediator of the risk of cerebral ischemia. J Neurosci Res 2023; 101:1840-1848. [PMID: 37724604 DOI: 10.1002/jnr.25245] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 08/15/2023] [Accepted: 09/04/2023] [Indexed: 09/21/2023]
Abstract
Pericytes are critical yet understudied cells that are a central component of the neurovascular unit. They are connected to the cerebrovascular endothelium and help control vascular contractility and maintain the blood-brain barrier. Pericyte dysfunction has the potential to mediate many of the deleterious vascular consequences of ischemic stroke. Current therapeutics are designed to be administered after stroke onset and limit damage, but there are few options to target vascular risk factors pre-ischemia which likely contribute to stroke outcomes. Here, we focus on the role of pericytes in health and disease, and discuss how pericyte dysfunction can increase the risk of ischemic injury. Additionally, we note that despite the importance of pericytes in cerebrovascular disease, there are relatively few current therapeutic options that target pericyte function.
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Affiliation(s)
- Bailey Whitehead
- Department of Neuroscience and Rockefeller Neuroscience Institute, West Virginia University, Morgantown, West Virginia, USA
| | - Kate Karelina
- Department of Neuroscience and Rockefeller Neuroscience Institute, West Virginia University, Morgantown, West Virginia, USA
| | - Zachary M Weil
- Department of Neuroscience and Rockefeller Neuroscience Institute, West Virginia University, Morgantown, West Virginia, USA
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5
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Brandl S, Reindl M. Blood-Brain Barrier Breakdown in Neuroinflammation: Current In Vitro Models. Int J Mol Sci 2023; 24:12699. [PMID: 37628879 PMCID: PMC10454051 DOI: 10.3390/ijms241612699] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/07/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023] Open
Abstract
The blood-brain barrier, which is formed by tightly interconnected microvascular endothelial cells, separates the brain from the peripheral circulation. Together with other central nervous system-resident cell types, including pericytes and astrocytes, the blood-brain barrier forms the neurovascular unit. Upon neuroinflammation, this barrier becomes leaky, allowing molecules and cells to enter the brain and to potentially harm the tissue of the central nervous system. Despite the significance of animal models in research, they may not always adequately reflect human pathophysiology. Therefore, human models are needed. This review will provide an overview of the blood-brain barrier in terms of both health and disease. It will describe all key elements of the in vitro models and will explore how different compositions can be utilized to effectively model a variety of neuroinflammatory conditions. Furthermore, it will explore the existing types of models that are used in basic research to study the respective pathologies thus far.
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Affiliation(s)
| | - Markus Reindl
- Clinical Department of Neurology, Medical University of Innsbruck, 6020 Innsbruck, Austria;
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Hirunpattarasilp C, Barkaway A, Davis H, Pfeiffer T, Sethi H, Attwell D. Hyperoxia evokes pericyte-mediated capillary constriction. J Cereb Blood Flow Metab 2022; 42:2032-2047. [PMID: 35786054 PMCID: PMC9580167 DOI: 10.1177/0271678x221111598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Oxygen supplementation is regularly prescribed to patients to treat or prevent hypoxia. However, excess oxygenation can lead to reduced cerebral blood flow (CBF) in healthy subjects and worsen the neurological outcome of critically ill patients. Most studies on the vascular effects of hyperoxia focus on arteries but there is no research on the effects on cerebral capillary pericytes, which are major regulators of CBF. Here, we used bright-field imaging of cerebral capillaries and modeling of CBF to show that hyperoxia (95% superfused O2) led to an increase in intracellular calcium level in pericytes and a significant capillary constriction, sufficient to cause an estimated 25% decrease in CBF. Although hyperoxia is reported to cause vascular smooth muscle cell contraction via generation of reactive oxygen species (ROS), endothelin-1 and 20-HETE, we found that increased cytosolic and mitochondrial ROS levels and endothelin release were not involved in the pericyte-mediated capillary constriction. However, a 20-HETE synthesis blocker greatly reduced the hyperoxia-evoked capillary constriction. Our findings establish pericytes as regulators of CBF in hyperoxia and 20-HETE synthesis as an oxygen sensor in CBF regulation. The results also provide a mechanism by which clinically administered oxygen can lead to a worse neurological outcome.
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Affiliation(s)
- Chanawee Hirunpattarasilp
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, UK.,Princess Srisavangavadhana College of Medicine, Chulabhorn Royal Academy, Bangkok, Thailand
| | - Anna Barkaway
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, UK.,Princess Srisavangavadhana College of Medicine, Chulabhorn Royal Academy, Bangkok, Thailand
| | - Harvey Davis
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, UK.,Princess Srisavangavadhana College of Medicine, Chulabhorn Royal Academy, Bangkok, Thailand
| | - Thomas Pfeiffer
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, UK
| | - Huma Sethi
- Division of Neurosurgery, UCL Queen Square Institute of Neurology, Queen Square, London, UK
| | - David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, UK
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Jehle A, Garaschuk O. The Interplay between cGMP and Calcium Signaling in Alzheimer’s Disease. Int J Mol Sci 2022; 23:ijms23137048. [PMID: 35806059 PMCID: PMC9266933 DOI: 10.3390/ijms23137048] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/31/2022] [Accepted: 06/22/2022] [Indexed: 02/04/2023] Open
Abstract
Cyclic guanosine monophosphate (cGMP) is a ubiquitous second messenger and a key molecule in many important signaling cascades in the body and brain, including phototransduction, olfaction, vasodilation, and functional hyperemia. Additionally, cGMP is involved in long-term potentiation (LTP), a cellular correlate of learning and memory, and recent studies have identified the cGMP-increasing drug Sildenafil as a potential risk modifier in Alzheimer’s disease (AD). AD development is accompanied by a net increase in the expression of nitric oxide (NO) synthases but a decreased activity of soluble guanylate cyclases, so the exact sign and extent of AD-mediated imbalance remain unclear. Moreover, human patients and mouse models of the disease present with entangled deregulation of both cGMP and Ca2+ signaling, e.g., causing changes in cGMP-mediated Ca2+ release from the intracellular stores as well as Ca2+-mediated cGMP production. Still, the mechanisms governing such interplay are poorly understood. Here, we review the recent data on mechanisms underlying the brain cGMP signaling and its interconnection with Ca2+ signaling. We also discuss the recent evidence stressing the importance of such interplay for normal brain function as well as in Alzheimer’s disease.
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8
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Impact of diabetes and ischemic stroke on the cerebrovasculature: A female perspective. Neurobiol Dis 2022; 167:105667. [PMID: 35227927 PMCID: PMC9615543 DOI: 10.1016/j.nbd.2022.105667] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 01/25/2022] [Accepted: 02/17/2022] [Indexed: 01/16/2023] Open
Abstract
There is a very complex interaction between the brain and the cerebral vasculature to meet the metabolic demands of the brain for proper function. Preservation of vascular networks and cerebrovascular function ultimately plays a key role in this intricate communication within the brain in health and disease. Experimental evidence showed that diabetes not only affects the architecture of cerebral blood arteries causing adverse remodeling, pathological neovascularization, and vasoregression, but also alters cerebrovascular function resulting in compromised myogenic reactivity and endothelial dysfunction. Coupled with the disruption of blood brain barrier (BBB) integrity, changes in blood flow and microbleeds into the brain can rapidly occur. When an ischemic insult is superimposed on this pathology, not only is the neurovascular injury greater, but repair mechanisms fail, resulting in greater physical and cognitive deficits. While clinically it is known that women suffer disproportionately from diabetes as well as ischemic stroke and post-stroke cognitive impairment, the cerebrovascular architecture, patho/physiology, as well as cerebrovascular contributions to stroke recovery in female and diabetic animal models are inadequately studied and highlighted in this review.
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9
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Archie SR, Al Shoyaib A, Cucullo L. Blood-Brain Barrier Dysfunction in CNS Disorders and Putative Therapeutic Targets: An Overview. Pharmaceutics 2021; 13:pharmaceutics13111779. [PMID: 34834200 PMCID: PMC8622070 DOI: 10.3390/pharmaceutics13111779] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/15/2021] [Accepted: 10/20/2021] [Indexed: 01/22/2023] Open
Abstract
The blood-brain barrier (BBB) is a fundamental component of the central nervous system (CNS). Its functional and structural integrity is vital to maintain the homeostasis of the brain microenvironment by controlling the passage of substances and regulating the trafficking of immune cells between the blood and the brain. The BBB is primarily composed of highly specialized microvascular endothelial cells. These cells’ special features and physiological properties are acquired and maintained through the concerted effort of hemodynamic and cellular cues from the surrounding environment. This complex multicellular system, comprising endothelial cells, astrocytes, pericytes, and neurons, is known as the neurovascular unit (NVU). The BBB strictly controls the transport of nutrients and metabolites into brain parenchyma through a tightly regulated transport system while limiting the access of potentially harmful substances via efflux transcytosis and metabolic mechanisms. Not surprisingly, a disruption of the BBB has been associated with the onset and/or progression of major neurological disorders. Although the association between disease and BBB disruption is clear, its nature is not always evident, specifically with regard to whether an impaired BBB function results from the pathological condition or whether the BBB damage is the primary pathogenic factor prodromal to the onset of the disease. In either case, repairing the barrier could be a viable option for treating and/or reducing the effects of CNS disorders. In this review, we describe the fundamental structure and function of the BBB in both healthy and altered/diseased conditions. Additionally, we provide an overview of the potential therapeutic targets that could be leveraged to restore the integrity of the BBB concomitant to the treatment of these brain disorders.
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Affiliation(s)
- Sabrina Rahman Archie
- Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, Amarillo, TX 79106, USA; (S.R.A.); (A.A.S.)
| | - Abdullah Al Shoyaib
- Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, Amarillo, TX 79106, USA; (S.R.A.); (A.A.S.)
| | - Luca Cucullo
- Department of Foundational Medical Studies, Oakland University William Beaumont School of Medicine, Rochester, MI 48309, USA
- Correspondence: ; Tel.: +1-248-370-3884; Fax: +1-248-370-4060
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10
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Hibbs E, Love S, Miners JS. Pericyte Contractile Responses to Endothelin-1 and Aβ Peptides: Assessment by Electrical Impedance Assay. Front Cell Neurosci 2021; 15:723953. [PMID: 34489644 PMCID: PMC8417582 DOI: 10.3389/fncel.2021.723953] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 07/28/2021] [Indexed: 11/13/2022] Open
Abstract
Pericytes are vascular mural cells that contract and relax in response to vasoactive stimuli to regulate neurovascular coupling and cerebral blood flow. Pericytes are damaged and degenerate in Alzheimer's disease (AD). We previously showed that the level of the regulatory vasoconstrictor, endothelin-1 (EDN1), is elevated in AD cerebral cortex and upregulated by amyloid-beta (Aβ). We have used electrical impedance analysis to monitor the contractile and proliferative response of cultured human fetal and adult brain-derived pericytes to EDN1 in real-time. EDN1 caused transient, dose-dependent contraction of fetal and adult brain pericytes that was mediated by EDN1 type A receptors and increased the subsequent proliferation of fetal but not adult cells. The contractile responses to EDN1 were weaker in the adult pericytes. The EDN1-mediated contractile response of fetal pericytes was unchanged after exposure to Aβ1 - 40 or Aβ1 - 42 (0.1-10 μM) for 1 h but both contraction and subsequent relaxation were significantly impaired upon exposure to Aβ for 24 h. These data suggest that chronic exposure to Aβ interferes with EDN1-mediated pericyte contractility, potentially contributing to neurovascular uncoupling and reduced cerebral blood flow in AD.
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Affiliation(s)
- Elliott Hibbs
- Dementia Research Group, Clinical Neurosciences, University of Bristol, Bristol, United Kingdom
| | - Seth Love
- Dementia Research Group, Clinical Neurosciences, University of Bristol, Bristol, United Kingdom
| | - J Scott Miners
- Dementia Research Group, Clinical Neurosciences, University of Bristol, Bristol, United Kingdom
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11
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Glück C, Ferrari KD, Binini N, Keller A, Saab AS, Stobart JL, Weber B. Distinct signatures of calcium activity in brain mural cells. eLife 2021; 10:e70591. [PMID: 34227466 PMCID: PMC8294852 DOI: 10.7554/elife.70591] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 06/15/2021] [Indexed: 12/15/2022] Open
Abstract
Pericytes have been implicated in various neuropathologies, yet little is known about their function and signaling pathways in health. Here, we characterized calcium dynamics of cortical mural cells in anesthetized or awake Pdgfrb-CreERT2;Rosa26< LSL-GCaMP6s > mice and in acute brain slices. Smooth muscle cells (SMCs) and ensheathing pericytes (EPs), also named as terminal vascular SMCs, revealed similar calcium dynamics in vivo. In contrast, calcium signals in capillary pericytes (CPs) were irregular, higher in frequency, and occurred in cellular microdomains. In the absence of the vessel constricting agent U46619 in acute slices, SMCs and EPs revealed only sparse calcium signals, whereas CPs retained their spontaneous calcium activity. Interestingly, chemogenetic activation of neurons in vivo and acute elevations of extracellular potassium in brain slices strongly decreased calcium activity in CPs. We propose that neuronal activation and an extracellular increase in potassium suppress calcium activity in CPs, likely mediated by Kir2.2 and KATP channels.
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Affiliation(s)
- Chaim Glück
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
| | - Kim David Ferrari
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
| | - Noemi Binini
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
| | - Annika Keller
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
- Department of Neurosurgery, University of ZurichSchlierenSwitzerland
| | - Aiman S Saab
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
| | - Jillian L Stobart
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Rady Faculty of Health Sciences, College of PharmacyWinnipegCanada
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
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12
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Butiaeva LI, Slutzki T, Swick HE, Bourguignon C, Robins SC, Liu X, Storch KF, Kokoeva MV. Leptin receptor-expressing pericytes mediate access of hypothalamic feeding centers to circulating leptin. Cell Metab 2021; 33:1433-1448.e5. [PMID: 34129812 DOI: 10.1016/j.cmet.2021.05.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 02/19/2021] [Accepted: 05/21/2021] [Indexed: 12/18/2022]
Abstract
Knowledge of how leptin receptor (LepR) neurons of the mediobasal hypothalamus (MBH) access circulating leptin is still rudimentary. Employing intravital microscopy, we found that almost half of the blood-vessel-enwrapping pericytes in the MBH express LepR. Selective disruption of pericytic LepR led to increased food intake, increased fat mass, and loss of leptin-dependent signaling in nearby LepR neurons. When delivered intravenously, fluorescently tagged leptin accumulated at hypothalamic LepR pericytes, which was attenuated upon pericyte-specific LepR loss. Because a paracellular tracer was also preferentially retained at LepR pericytes, we pharmacologically targeted regulators of inter-endothelial junction tightness and found that they affect LepR neuronal signaling and food intake. Optical imaging in MBH slices revealed a long-lasting, tonic calcium increase in LepR pericytes in response to leptin, suggesting pericytic contraction and vessel constriction. Together, our data indicate that LepR pericytes facilitate localized, paracellular blood-brain barrier leaks, enabling MBH LepR neurons to access circulating leptin.
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Affiliation(s)
- Liliia I Butiaeva
- Division of Endocrinology, Department of Medicine, McGill University Health Center Research Institute, McGill University, Montreal QC H4A 3J1, Canada; Integrated Program in Neuroscience, McGill University, Montreal QC H3A 2B4, Canada
| | - Tal Slutzki
- Division of Endocrinology, Department of Medicine, McGill University Health Center Research Institute, McGill University, Montreal QC H4A 3J1, Canada; Integrated Program in Neuroscience, McGill University, Montreal QC H3A 2B4, Canada
| | - Hannah E Swick
- Division of Endocrinology, Department of Medicine, McGill University Health Center Research Institute, McGill University, Montreal QC H4A 3J1, Canada; Integrated Program in Neuroscience, McGill University, Montreal QC H3A 2B4, Canada
| | - Clément Bourguignon
- Department of Psychiatry, Douglas Mental Health University Institute, McGill University, Montreal QC H4H 1R3, Canada; Integrated Program in Neuroscience, McGill University, Montreal QC H3A 2B4, Canada
| | - Sarah C Robins
- Division of Endocrinology, Department of Medicine, McGill University Health Center Research Institute, McGill University, Montreal QC H4A 3J1, Canada
| | - Xiaohong Liu
- Division of Endocrinology, Department of Medicine, McGill University Health Center Research Institute, McGill University, Montreal QC H4A 3J1, Canada
| | - Kai-Florian Storch
- Department of Psychiatry, Douglas Mental Health University Institute, McGill University, Montreal QC H4H 1R3, Canada
| | - Maia V Kokoeva
- Division of Endocrinology, Department of Medicine, McGill University Health Center Research Institute, McGill University, Montreal QC H4A 3J1, Canada.
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13
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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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14
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Kadry H, Noorani B, Cucullo L. A blood-brain barrier overview on structure, function, impairment, and biomarkers of integrity. Fluids Barriers CNS 2020; 17:69. [PMID: 33208141 PMCID: PMC7672931 DOI: 10.1186/s12987-020-00230-3] [Citation(s) in RCA: 602] [Impact Index Per Article: 150.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 11/07/2020] [Indexed: 02/07/2023] Open
Abstract
The blood–brain barrier is playing a critical role in controlling the influx and efflux of biological substances essential for the brain’s metabolic activity as well as neuronal function. Thus, the functional and structural integrity of the BBB is pivotal to maintain the homeostasis of the brain microenvironment. The different cells and structures contributing to developing this barrier are summarized along with the different functions that BBB plays at the brain–blood interface. We also explained the role of shear stress in maintaining BBB integrity. Furthermore, we elaborated on the clinical aspects that correlate between BBB disruption and different neurological and pathological conditions. Finally, we discussed several biomarkers that can help to assess the BBB permeability and integrity in-vitro or in-vivo and briefly explain their advantages and disadvantages.
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Affiliation(s)
- Hossam Kadry
- Department of Pharmaceutical Sciences, Jerry H. Hodge School of Pharmacy, Texas Tech University Health Sciences Center, 1300 S. Coulter Street, Amarillo, TX, 79106, USA
| | - Behnam Noorani
- Department of Pharmaceutical Sciences, Jerry H. Hodge School of Pharmacy, Texas Tech University Health Sciences Center, 1300 S. Coulter Street, Amarillo, TX, 79106, USA
| | - Luca Cucullo
- Dept. of Foundational Medical Studies, Oakland University William Beaumont School of Medicine, Office 415, Rochester, MI, 48309, USA.
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15
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Alcendor DJ. Dysregulation of Endothelin-1: Implications for Health Disparities in Alzheimer's Disease. J Pers Med 2020; 10:E199. [PMID: 33126567 PMCID: PMC7712547 DOI: 10.3390/jpm10040199] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/24/2020] [Accepted: 10/26/2020] [Indexed: 02/07/2023] Open
Abstract
Alzheimer's disease (AD) and related dementias disproportionately impact racial and ethnic minorities. The racial and ethnic disparities in AD could be explained by differences in cerebral vascular disease pathology. Endothelin-1 (ET-1) is a potent vasoconstrictive peptide that regulates smooth muscle, endothelial cell, and pericyte contractions that may result in cerebral vascular constriction, leading to cerebral hypoperfusion; over time, ET-1 may result in neuronal injury contributing to the pathology of AD. Upregulation of the ET-1 system has been observed in African Americans when compared with non-Hispanic Whites. The role of the ET-1 system as a driver of ethnic disparities in AD requires further investigation. Targeting of the ET-1 system as a therapeutic intervention that could impact AD progression also needs further study. Dysregulation of ET-1 in Hispanic/Latino populations largely have been unexplored. Genetics linking ET-1 dysregulation and racial disparities in AD also needs further investigation. In this review, I examine how AD effects underserved minority populations and how dysregulation of the ET-1 system specifically predisposes ethnic minorities to AD. In addition, I examine the molecular interactions of the ET-1 system and amyloid beta, the role the ET-1 system in neurodegeneration, potential therapeutics for ET-1 dysregulation, and the impact on AD progression.
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Affiliation(s)
- Donald J Alcendor
- Center for AIDS Health Disparities Research, Department of Microbiology, Immunology and Physiology, School of Medicine, Meharry Medical College, Nashville, TN 37208, USA
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16
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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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17
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Bahrami N, Childs SJ. Development of vascular regulation in the zebrafish embryo. Development 2020; 147:147/10/dev183061. [PMID: 32423977 DOI: 10.1242/dev.183061] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 04/07/2020] [Indexed: 01/03/2023]
Abstract
The thin endothelial wall of a newly formed vessel is under enormous stress at the onset of blood flow, rapidly acquiring support from mural cells (pericytes and vascular smooth muscle cells; vSMCs) during development. Mural cells then develop vasoactivity (contraction and relaxation) but we have little information as to when this first develops or the extent to which pericytes and vSMCs contribute. For the first time, we determine the dynamic developmental acquisition of vasoactivity in vivo in the cerebral vasculature of zebrafish. We show that pericyte-covered vessels constrict in response to α1-adrenergic receptor agonists and dilate in response to nitric oxide donors at 4 days postfertilization (dpf) but have heterogeneous responses later, at 6 dpf. In contrast, vSMC-covered vessels constrict at 6 dpf, and dilate at both stages. Using genetic ablation, we demonstrate that vascular constriction and dilation is an active response. Our data suggest that both pericyte- and vSMC-covered vessels regulate their diameter in early development, and that their relative contributions change over developmental time.
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Affiliation(s)
- Nabila Bahrami
- Alberta Children's Hospital Research Institute and Department of Biochemistry and Molecular Biology, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada
| | - Sarah J Childs
- Alberta Children's Hospital Research Institute and Department of Biochemistry and Molecular Biology, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada
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18
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Abrahamson EE, Ikonomovic MD. Brain injury-induced dysfunction of the blood brain barrier as a risk for dementia. Exp Neurol 2020; 328:113257. [PMID: 32092298 DOI: 10.1016/j.expneurol.2020.113257] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 01/31/2020] [Accepted: 02/20/2020] [Indexed: 02/06/2023]
Abstract
The blood-brain barrier (BBB) is a complex and dynamic physiological interface between brain parenchyma and cerebral vasculature. It is composed of closely interacting cells and signaling molecules that regulate movement of solutes, ions, nutrients, macromolecules, and immune cells into the brain and removal of products of normal and abnormal brain cell metabolism. Dysfunction of multiple components of the BBB occurs in aging, inflammatory diseases, traumatic brain injury (TBI, severe or mild repetitive), and in chronic degenerative dementing disorders for which aging, inflammation, and TBI are considered risk factors. BBB permeability changes after TBI result in leakage of serum proteins, influx of immune cells, perivascular inflammation, as well as impairment of efflux transporter systems and accumulation of aggregation-prone molecules involved in hallmark pathologies of neurodegenerative diseases with dementia. In addition, cerebral vascular dysfunction with persistent alterations in cerebral blood flow and neurovascular coupling contribute to brain ischemia, neuronal degeneration, and synaptic dysfunction. While the idea of TBI as a risk factor for dementia is supported by many shared pathological features, it remains a hypothesis that needs further testing in experimental models and in human studies. The current review focusses on pathological mechanisms shared between TBI and neurodegenerative disorders characterized by accumulation of pathological protein aggregates, such as Alzheimer's disease and chronic traumatic encephalopathy. We discuss critical knowledge gaps in the field that need to be explored to clarify the relationship between TBI and risk for dementia and emphasize the need for longitudinal in vivo studies using imaging and biomarkers of BBB dysfunction in people with single or multiple TBI.
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Affiliation(s)
- Eric E Abrahamson
- Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, University of Pittsburgh, Pittsburgh, PA, United States; Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Milos D Ikonomovic
- Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, University of Pittsburgh, Pittsburgh, PA, United States; Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States; Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States.
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19
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Arango-Lievano M, Boussadia B, De Terdonck LDT, Gault C, Fontanaud P, Lafont C, Mollard P, Marchi N, Jeanneteau F. Topographic Reorganization of Cerebrovascular Mural Cells under Seizure Conditions. Cell Rep 2019; 23:1045-1059. [PMID: 29694884 DOI: 10.1016/j.celrep.2018.03.110] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 01/04/2018] [Accepted: 03/22/2018] [Indexed: 12/27/2022] Open
Abstract
Reorganization of the neurovascular unit has been suggested in the epileptic brain, although the dynamics and functional significance remain unclear. Here, we tracked the in vivo dynamics of perivascular mural cells as a function of electroencephalogram (EEG) activity following status epilepticus. We segmented the cortical vascular bed to provide a size- and type-specific analysis of mural cell plasticity topologically. We find that mural cells are added and removed from veins, arterioles, and capillaries after seizure induction. Loss of mural cells is proportional to seizure severity and vascular pathology (e.g., rigidity, perfusion, and permeability). Treatment with platelet-derived growth factor subunits BB (PDGF-BB) reduced mural cell loss, vascular pathology, and epileptiform EEG activity. We propose that perivascular mural cells play a pivotal role in seizures and are potential targets for reducing pathophysiology.
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Affiliation(s)
- Margarita Arango-Lievano
- Departments of Neuroscience & Physiology, Laboratory of Stress Hormones & Plasticity, Institut de Génomique Fonctionnelle, INSERM, CNRS, University of Montpellier, 34093 Montpellier, France.
| | - Badreddine Boussadia
- Department of Neuroscience, Laboratory of Cerebrovascular Mechanisms of Brain Disorders, Institut de Génomique Fonctionnelle, INSERM, CNRS, University of Montpellier, 34093 Montpellier, France
| | - Lucile Du Trieu De Terdonck
- Departments of Neuroscience & Physiology, Laboratory of Stress Hormones & Plasticity, Institut de Génomique Fonctionnelle, INSERM, CNRS, University of Montpellier, 34093 Montpellier, France
| | - Camille Gault
- Departments of Neuroscience & Physiology, Laboratory of Stress Hormones & Plasticity, Institut de Génomique Fonctionnelle, INSERM, CNRS, University of Montpellier, 34093 Montpellier, France
| | - Pierre Fontanaud
- Department of Physiology, Laboratory of Networks and Rhythms in Endocrine Glands, Institut de Génomique Fonctionnelle, INSERM, CNRS, University of Montpellier, 34093 Montpellier, France
| | - Chrystel Lafont
- Department of Physiology, Laboratory of Networks and Rhythms in Endocrine Glands, Institut de Génomique Fonctionnelle, INSERM, CNRS, University of Montpellier, 34093 Montpellier, France
| | - Patrice Mollard
- Department of Physiology, Laboratory of Networks and Rhythms in Endocrine Glands, Institut de Génomique Fonctionnelle, INSERM, CNRS, University of Montpellier, 34093 Montpellier, France
| | - Nicola Marchi
- Department of Neuroscience, Laboratory of Cerebrovascular Mechanisms of Brain Disorders, Institut de Génomique Fonctionnelle, INSERM, CNRS, University of Montpellier, 34093 Montpellier, France.
| | - Freddy Jeanneteau
- Departments of Neuroscience & Physiology, Laboratory of Stress Hormones & Plasticity, Institut de Génomique Fonctionnelle, INSERM, CNRS, University of Montpellier, 34093 Montpellier, France.
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20
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Abstract
Microcirculation is the generic name for the finest level of the circulatory system and consists of arteriolar and venular networks located upstream and downstream of capillaries, respectively. Anatomically arterioles are surrounded by a monolayer of spindle-shaped smooth muscle cells (myocytes), while terminal branches of precapillary arterioles, capillaries and all sections of postcapillary venules are surrounded by a monolayer of morphologically different perivascular cells (pericytes). Pericytes are essential components of the microvascular vessel wall. Wrapped around endothelial cells, they occupy a strategic position at the interface between the circulating blood and the interstitial space. There are physiological differences in the responses of pericytes and myocytes to vasoactive molecules, which suggest that these two types of vascular cells could have different functional roles in the regulation of local blood flow within the same microvascular bed. Also, pericytes may play different roles in different microcirculatory beds to meet the characteristics of individual organs. Contractile activity of pericytes and myocytes is controlled by changes of cytosolic free Ca2+concentration. In this chapter, we attempt to summarize the results in the field of Ca2+ signalling in pericytes especially in light of their contractile roles in different tissues and organs. We investigate the literature and describe our results regarding sources of Ca2+, relative importance and mechanisms of Ca2+ release and Ca2+ entry in control of the spatio-temporal characteristics of the Ca2+ signals in pericytes, where possible Ca2+ signalling and contractile responses in pericytes are compared to those of myocytes.
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21
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Prieto P, Blaauboer BJ, de Boer AG, Boveri M, Cecchelli R, Clemedson C, Coecke S, Forsby A, Galla HJ, Garberg P, Greenwood J, Price A, Tähti H. Blood-Brain Barrier In Vitro Models and Their Application in Toxicology: The Report and Recommendations of ECVAM Workshop 49,. Altern Lab Anim 2019; 32:37-50. [PMID: 15603552 DOI: 10.1177/026119290403200107] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Pilar Prieto
- ECVAM, Institute for Health & Consumer Protection, European Commission Joint Research Centre, 21020 Ispra (VA), Italy.
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22
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Fouda AY, Fagan SC, Ergul A. Brain Vasculature and Cognition. Arterioscler Thromb Vasc Biol 2019; 39:593-602. [PMID: 30816798 PMCID: PMC6540805 DOI: 10.1161/atvbaha.118.311906] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 02/15/2019] [Indexed: 12/18/2022]
Abstract
There is a complex interaction between the brain and the cerebral vasculature to meet the metabolic demands of the brain for proper function. Preservation of cerebrovascular function and integrity has a central role in this sophisticated communication within the brain, and any derangements can have deleterious acute and chronic consequences. In almost all forms of cognitive impairment, from mild to Alzheimer disease, there are changes in cerebrovascular function and structure leading to decreased cerebral blood flow, which may initiate or worsen cognitive impairment. In this focused review, we discuss the contribution of 2 major vasoactive pathways to cerebrovascular dysfunction and cognitive impairment in an effort to identify early intervention strategies.
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Affiliation(s)
- Abdelrahman Y. Fouda
- Vascular Biology Center, Augusta University, GA
- Charlie Norwood VA Medical Center Augusta, GA
| | - Susan C. Fagan
- Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, GA
- Charlie Norwood VA Medical Center Augusta, GA
| | - Adviye Ergul
- Ralph Johnson Veterans Administration Medical Center, Medical University of South Carolina, Charleston, SC
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC
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23
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Li W, Abdul Y, Ward R, Ergul A. Endothelin and diabetic complications: a brain-centric view. Physiol Res 2018; 67:S83-S94. [PMID: 29947530 DOI: 10.33549/physiolres.933833] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The global epidemic of diabetes is of significant concern. Diabetes associated vascular disease signifies the principal cause of morbidity and mortality in diabetic patients. It is also the most rapidly increasing risk factor for cognitive impairment, a silent disease that causes loss of creativity, productivity, and quality of life. Small vessel disease in the cerebral vasculature plays a major role in the pathogenesis of cognitive impairment in diabetes. Endothelin system, including endothelin-1 (ET-1) and the receptors (ET(A) and ET(B)), is a likely candidate that may be involved in many aspects of the diabetes cerebrovascular disease. In this review, we took a brain-centric approach and discussed the role of the ET system in cerebrovascular and cognitive dysfunction in diabetes.
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Affiliation(s)
- W Li
- Charlie Norwood Veterans Affairs Medical Center, Augusta, Georgia, USA, Department of Physiology, Augusta University, Augusta, Georgia, USA.
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24
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Neuhaus AA, Couch Y, Sutherland BA, Buchan AM. Novel method to study pericyte contractility and responses to ischaemia in vitro using electrical impedance. J Cereb Blood Flow Metab 2017; 37:2013-2024. [PMID: 27418036 PMCID: PMC5464697 DOI: 10.1177/0271678x16659495] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Pericytes are contractile vascular mural cells overlying capillary endothelium, and they have been implicated in a variety of functions including regulation of cerebral blood flow. Recent work has suggested that both in vivo and ex vivo, ischaemia causes pericytes to constrict and die, which has implications for microvascular reperfusion. Assessing pericyte contractility in tissue slices and in vivo is technically challenging, while in vitro techniques remain unreliable. Here, we used isolated cultures of human brain vascular pericytes to examine their contractile potential in vitro using the iCelligence electrical impedance system. Contraction was induced using the vasoactive peptide endothelin-1, and relaxation was demonstrated using adenosine and sodium nitroprusside. Endothelin-1 treatment also resulted in increased proliferation, which we were able to monitor in the same cell population from which we recorded contractile responses. Finally, the observation of pericyte contraction in stroke was reproduced using chemical ischaemia, which caused a profound and irreversible contraction clearly preceding cell death. These data demonstrate that isolated pericytes retain a contractile phenotype in vitro, and that it is possible to quantify this contraction using real-time electrical impedance recordings, providing a significant new platform for assessing the effects of vasoactive and vasculoprotective compounds on pericyte contractility.
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Affiliation(s)
- Ain A Neuhaus
- 1 Acute Stroke Programme, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Yvonne Couch
- 1 Acute Stroke Programme, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Brad A Sutherland
- 1 Acute Stroke Programme, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.,4 School of Medicine, Faculty of Health, University of Tasmania, Hobart, Australia
| | - Alastair M Buchan
- 1 Acute Stroke Programme, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.,2 Medical Sciences Division, University of Oxford, Oxford, UK.,3 Acute Vascular Imaging Centre, University of Oxford, Oxford University Hospitals, Oxford, UK
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25
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Lee K, Chae MS, Cho SG, Go HY, Sun SH, Jang J, Jung KY, Choi YK, Song YK, Sim SY, Lee HL, Kang MS, Jeon CY, Ko SG. Inhibitory effect of Angelica gigas on cold‑induced RhoA activation in vascular cells. Mol Med Rep 2017; 15:3143-3146. [PMID: 28350093 DOI: 10.3892/mmr.2017.6404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 02/15/2017] [Indexed: 11/06/2022] Open
Abstract
The herbal extract Angelica gigas (AG) has been applied as a vasodilating agent for patients suffering from vascular diseases for many years; however, the underlying mechanism has not been fully elucidated. The present study hypothesized that the anti‑vasoconstrictive effect of AG may be effective in the treatment of abnormal cold‑mediated vasospasms that occur in Raynaud's phenomenon (RP). The effect of AG on the activity of ras homolog gene family member A (RhoA) was investigated in cold‑exposed vascular cells. Vascular cells were pretreated to AG, followed by a warm (37˚C) or cold (25˚C) incubation for 30 min and investigated with western blotting, ELISA and confocal microscopy. Cold treatment induced the activation of RhoA in pericytes and vascular endothelial cells, however this was reduced by treatment with AG. Furthermore, AG treatment reduced the endothelin‑1 (ET‑1)‑mediated RhoA activation in pericytes; however, cold‑induced ET‑1 production by vascular endothelial cells was not affected by treatment with AG. In addition, AG treatment suppressed the formation of stress fibers and focal adhesion complexes, and the cold‑induced phosphorylation of focal adhesion kinase, proto‑oncogene tyrosine‑protein kinase Src and extracellular signal‑related kinase. Therefore, AG treatment demonstrated an ability to reduce cold‑induced RhoA activation in pericytes and vascular endothelial cells, and attenuated ET‑1‑mediated RhoA activation in pericytes. In conclusion, the present study indicated that AG may be useful for the treatment of RP.
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Affiliation(s)
- Kangwook Lee
- Department of Science in Korean Medicine, Graduate School, Kyung Hee University, Seoul 02477, Republic of Korea
| | - Min Soo Chae
- Department of Korean Medicine Obstetrics & Gynecology, Graduate School, Kyung Hee University, Seoul 02477, Republic of Korea
| | - Sung-Gook Cho
- Department of Biotechnology, Korea National University of Transportation, Cheongju, Chungbuk 27469, Republic of Korea
| | - Ho Yeon Go
- Department of Korean Internal Medicine, College of Korean Medicine, Semyung University, Chungju, Chungbuk 27136, Republic of Korea
| | - Seung-Ho Sun
- Department of Oriental Internal Medicine, College of Korean Medicine, Sangji University, Wonju, Gangwon 23339, Republic of Korea
| | - Junbock Jang
- Department of Korean Medicine Obstetrics and Gynecology, College of Korean Medicine, Kyung Hee University, Seoul 02477, Republic of Korea
| | - Ki-Yong Jung
- Department of Korean Internal Medicine, College of Korean Medicine, Gachon University, Seongnam, Gyeonggi 13120, Republic of Korea
| | - You-Kyung Choi
- Department of Korean Internal Medicine, College of Korean Medicine, Gachon University, Seongnam, Gyeonggi 13120, Republic of Korea
| | - Yun-Kyung Song
- Department of Korean Rehabilitation Medicine, College of Korean Medicine, Gachon University, Seongnam, Gyeonggi 461701, Republic of Korea
| | - Sung Yong Sim
- Department of Korean Ophthalmology & Otolaryngology, College of Korean Medicine, Gachon University, Seongnam, Gyeonggi 461701, Republic of Korea
| | - Hye Lim Lee
- Department of Korean Pediatrics, College of Korean Medicine, Gachon University, Seongnam, Gyeonggi 461701, Republic of Korea
| | - Mi Suk Kang
- Department of Acupuncture and Moxibustion Medicine, College of Korean Medicine, Gachon University, Seongnam, Gyeonggi 461701, Republic of Korea
| | - Chan-Yong Jeon
- Department of Korean Internal Medicine, College of Korean Medicine, Gachon University, Seongnam, Gyeonggi 13120, Republic of Korea
| | - Seong Gyu Ko
- Department of Preventive Medicine, College of Korean Medicine, Kyung Hee University, Seoul 02453, Republic of Korea
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26
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Lee K, Cho SG, Woo SM, Kim AJ, Lee KM, Go HY, Sun SH, Kim TH, Jung KY, Choi YK, Lim EM, Song YK, Park JH, Jun CY, Ko SG. Danggui-Sayuk-Ga-Osuyu-Senggang-Tang ameliorates cold-induced vasoconstriction in vitro and in vivo. Mol Med Rep 2016; 14:4723-4728. [DOI: 10.3892/mmr.2016.5805] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 08/05/2016] [Indexed: 11/06/2022] Open
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27
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Kumar H, Ropper AE, Lee SH, Han I. Propitious Therapeutic Modulators to Prevent Blood-Spinal Cord Barrier Disruption in Spinal Cord Injury. Mol Neurobiol 2016; 54:3578-3590. [PMID: 27194298 DOI: 10.1007/s12035-016-9910-6] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Accepted: 05/03/2016] [Indexed: 01/09/2023]
Abstract
The blood-spinal cord barrier (BSCB) is a specialized protective barrier that regulates the movement of molecules between blood vessels and the spinal cord parenchyma. Analogous to the blood-brain barrier (BBB), the BSCB plays a crucial role in maintaining the homeostasis and internal environmental stability of the central nervous system (CNS). After spinal cord injury (SCI), BSCB disruption leads to inflammatory cell invasion such as neutrophils and macrophages, contributing to permanent neurological disability. In this review, we focus on the major proteins mediating the BSCB disruption or BSCB repair after SCI. This review is composed of three parts. Section 1. SCI and the BSCB of the review describes critical events involved in the pathophysiology of SCI and their correlation with BSCB integrity/disruption. Section 2. Major proteins involved in BSCB disruption in SCI focuses on the actions of matrix metalloproteinases (MMPs), tumor necrosis factor alpha (TNF-α), heme oxygenase-1 (HO-1), angiopoietins (Angs), bradykinin, nitric oxide (NO), and endothelins (ETs) in BSCB disruption and repair. Section 3. Therapeutic approaches discusses the major therapeutic compounds utilized to date for the prevention of BSCB disruption in animal model of SCI through modulation of several proteins.
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Affiliation(s)
- Hemant Kumar
- Department of Neurosurgery, CHA University, CHA Bundang Medical Center, Seongnam-si, Gyeonggi-do, 13496, Republic of Korea
| | - Alexander E Ropper
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX, USA
| | - Soo-Hong Lee
- Department of Biomedical Science, CHA University, Seongnam-si, Gyeonggi-do, 13488, Republic of Korea.
| | - Inbo Han
- Department of Neurosurgery, CHA University, CHA Bundang Medical Center, Seongnam-si, Gyeonggi-do, 13496, Republic of Korea.
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Pancotto TE, Rossmeisl JH, Huckle WR, Inzana KD, Zimmerman KL. Evaluation of endothelin-1 and MMPs-2, -9, -14 in cerebrospinal fluid as indirect indicators of blood-brain barrier dysfunction in chronic canine hypothyroidism. Res Vet Sci 2016; 105:115-20. [PMID: 27033918 DOI: 10.1016/j.rvsc.2016.01.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 11/19/2015] [Accepted: 01/24/2016] [Indexed: 11/27/2022]
Abstract
Chronic canine hypothyroidism is associated with blood-brain barrier (BBB) disruption. We hypothesized that this change is mediated by endothelin-1(ET-1) and matrix metalloproteinases (MMP) -2, -9, and -14, as evidenced by increased concentrations of these proteins in cerebrospinal fluid (CSF) compared to controls. CSF from 18 dogs, 9 controls and 9 with experimentally induced hypothyroidism was collected before and 6, 12, and 18 months after induction of hypothyroidism. Concentrations of ET-1 using an ELISA kit, and for MMP-2, -9, and -14 using gelatinase zymography were measured in CSF. ET-1 was undetectable in CSF of control and hypothyroid dogs at all time-points. Constitutively expressed MMP-2 was detectable in CSF samples in all dogs at all time-points. No other MMPs were detectable in CSF. No differences in CSF concentrations of ET-1 and MMP-2, 9, and 14 were found between hypothyroid and euthyroid dogs. Therefore, ET-1 and MMP-2, 9, and 14 are unlikely to be primary mediators of BBB damage in chronically hypothyroid dogs.
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Affiliation(s)
- Theresa E Pancotto
- Department of Small Animal Clinical Sciences, Virginia Maryland College of Veterinary Medicine, 225 Duck Pond Drive, Virginia Tech, Blacksburg, VA, 24061, United States.
| | - John H Rossmeisl
- Department of Small Animal Clinical Sciences, Virginia Maryland College of Veterinary Medicine, 225 Duck Pond Drive, Virginia Tech, Blacksburg, VA, 24061, United States
| | - William R Huckle
- Department of Pathobiology, Virginia Maryland College of Veterinary Medicine, 225 Duck Pond Drive, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Karen D Inzana
- Department of Small Animal Clinical Sciences, Virginia Maryland College of Veterinary Medicine, 225 Duck Pond Drive, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Kurt L Zimmerman
- Department of Pathobiology, Virginia Maryland College of Veterinary Medicine, 225 Duck Pond Drive, Virginia Tech, Blacksburg, VA, 24061, United States
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Worzfeld T, Schwaninger M. Apicobasal polarity of brain endothelial cells. J Cereb Blood Flow Metab 2016; 36:340-62. [PMID: 26661193 PMCID: PMC4759676 DOI: 10.1177/0271678x15608644] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 09/07/2015] [Indexed: 01/24/2023]
Abstract
Normal brain homeostasis depends on the integrity of the blood-brain barrier that controls the access of nutrients, humoral factors, and immune cells to the CNS. The blood-brain barrier is composed mainly of brain endothelial cells. Forming the interface between two compartments, they are highly polarized. Apical/luminal and basolateral/abluminal membranes differ in their lipid and (glyco-)protein composition, allowing brain endothelial cells to secrete or transport soluble factors in a polarized manner and to maintain blood flow. Here, we summarize the basic concepts of apicobasal cell polarity in brain endothelial cells. To address potential molecular mechanisms underlying apicobasal polarity in brain endothelial cells, we draw on investigations in epithelial cells and discuss how polarity may go awry in neurological diseases.
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Affiliation(s)
- Thomas Worzfeld
- Institute of Pharmacology, Biochemical-Pharmacological Center (BPC), University of Marburg, Marburg, Germany Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Markus Schwaninger
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Lübeck, Germany German Research Centre for Cardiovascular Research, DZHK, Lübeck, Germany
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The evolving roles of pericyte in early brain injury after subarachnoid hemorrhage. Brain Res 2015; 1623:110-22. [PMID: 25982598 DOI: 10.1016/j.brainres.2015.05.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 05/02/2015] [Accepted: 05/04/2015] [Indexed: 12/21/2022]
Abstract
Despite accumulated understanding on the mechanisms of early brain injury and improved management of subarachnoid hemorrhage (SAH), it is still one of the serious and refractory health problems around the world. Traditionally, pericyte, served as capillary contraction handler, is recently considered as the main participant of microcirculation regulation in SAH pathophysiology. However, accumulate evidences indicate that pericyte is much more than we already know. Therefore, we briefly review the characteristics, regulation pathways and functions of pericyte, aim to summarize the evolving new pathophysiological roles of pericyte that are implicated in early brain injury after SAH and to improve our understanding in order to explore potential novel therapeutic options for patients with SAH. This article is part of a Special Issue entitled SI: Cell Interactions In Stroke.
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Candela P, Saint-Pol J, Kuntz M, Boucau MC, Lamartiniere Y, Gosselet F, Fenart L. In vitro discrimination of the role of LRP1 at the BBB cellular level: focus on brain capillary endothelial cells and brain pericytes. Brain Res 2014; 1594:15-26. [PMID: 25451130 DOI: 10.1016/j.brainres.2014.10.047] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 10/23/2014] [Indexed: 01/10/2023]
Abstract
Several studies have demonstrated that the blood-brain barrier (BBB) (dynamic cellular complex composed by brain capillary endothelial cells (BCECs) and surrounded by astrocytic end feet and pericytes) regulates the exchanges of amyloid β (Aβ) peptide between the blood and the brain. Deregulation of these exchanges seems to be a key trigger for the brain accumulation of Aβ peptide observed in Alzheimer's disease (AD). Whereas the involvement of receptor for advanced glycation end-products in Aβ peptide transcytosis has been demonstrated in our laboratory, low-density lipoprotein receptor's role at the cellular level needs to be clarified. For this, we used an in vitro BBB model that consists of a co-culture of bovine BCECs and rat glial cells. This model has already been used to characterize low-density lipoprotein receptor-related peptide (LRP)'s involvement in the transcytosis of molecules such as tPA and angiopep-2. Our results suggest that Aβ peptide efflux across the BCEC monolayer involves a transcellular transport. However, the experiments with RAP discard an involvement of LRP family members at BCECs level. In contrast, our results show a strong transcriptional expression of LRP1 in pericytes and suggest its implication in Aβ endocytosis. Moreover, the observations of pericytes contraction and local downregulation of LRP1 in response to Aβ treatment opens up perspectives for studying this cell type with respect to Aβ peptide metabolism and AD.
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Affiliation(s)
- Pietra Candela
- University of Lille Nord de France, Lille, France; Artois University, LBHE, EA 2465, Lens, France; IMPRT-IFR114, Lille, France.
| | - Julien Saint-Pol
- University of Lille Nord de France, Lille, France; Artois University, LBHE, EA 2465, Lens, France; IMPRT-IFR114, Lille, France
| | - Mélanie Kuntz
- University of Lille Nord de France, Lille, France; Artois University, LBHE, EA 2465, Lens, France; IMPRT-IFR114, Lille, France
| | - Marie-Christine Boucau
- University of Lille Nord de France, Lille, France; Artois University, LBHE, EA 2465, Lens, France; IMPRT-IFR114, Lille, France
| | - Yordenca Lamartiniere
- University of Lille Nord de France, Lille, France; Artois University, LBHE, EA 2465, Lens, France; IMPRT-IFR114, Lille, France
| | - Fabien Gosselet
- University of Lille Nord de France, Lille, France; Artois University, LBHE, EA 2465, Lens, France; IMPRT-IFR114, Lille, France
| | - Laurence Fenart
- University of Lille Nord de France, Lille, France; Artois University, LBHE, EA 2465, Lens, France; IMPRT-IFR114, Lille, France
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Burdyga T, Borysova L. Calcium signalling in pericytes. J Vasc Res 2014; 51:190-9. [PMID: 24903335 DOI: 10.1159/000362687] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 04/06/2014] [Indexed: 11/19/2022] Open
Abstract
Recent advances in pericyte research have contributed to our understanding of the physiology and pathophysiology of microvessels. The microvasculature consists of arteriolar and venular networks located upstream and downstream of the capillaries. Arterioles are surrounded by a monolayer of spindle-shaped myocytes, while terminal branches of precapillary arterioles, capillaries and all sections of postcapillary venules are encircled by a monolayer of morphologically diverse pericytes. There are physiological differences in the response of pericytes and myocytes to vasoactive molecules, suggesting that these two vascular cell types could have different functional roles in the regulation of local blood flow. The contractile activity of pericytes and myocytes is controlled by changes of cytosolic free Ca(2+) concentration. In this short review, we summarize our results and those of other authors on the contractility of pericytes and their Ca(2+) signalling. We describe results regarding sources of Ca(2+) and mechanisms of Ca(2+) release and Ca(2+) entry in control of the spatiotemporal characteristics of the Ca(2+) signals in pericytes.
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Affiliation(s)
- Theodor Burdyga
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
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Guo J, Li Y, He Z, Zhang B, Li Y, Hu J, Han M, Xu Y, Li Y, Gu J, Dai B, Chen Z. Targeting endothelin receptors A and B attenuates the inflammatory response and improves locomotor function following spinal cord injury in mice. Int J Mol Med 2014; 34:74-82. [PMID: 24756152 PMCID: PMC4072339 DOI: 10.3892/ijmm.2014.1751] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Accepted: 04/01/2014] [Indexed: 11/06/2022] Open
Abstract
After spinal cord injury (SCI), the disruption of blood-spinal cord barrier by activation of the endothelin (ET) system is a critical event leading to leukocyte infiltration, inflammatory response and oxidative stress, contributing to neurological disability. In the present study, we showed that blockade of ET receptor A (ETAR) and/or ET receptor B (ETBR) prevented early inflammatory responses directly via the inhibition of neutrophil and monocyte diapedesis and inflammatory mediator production following traumatic SCI in mice. Long-term neurological improvement, based on a series of tests of locomotor performance, occurred only in the spinal cord‑injured mice following blockade of ETAR and ETBR. We also examined the post‑traumatic changes of the micro-environment within the injured spinal cord of mice following blockade of ET receptors. Oxidative stress reflects an imbalance between malondialdehyde and superoxide dismutase in spinal cord‑injured mice treated with vehicle, whereas blockade of ETAR and ETBR reversed the oxidation state imbalance. In addition, hemeoxygenase-1, a protective protease involved in early SCI, was increased in spinal cord‑injured mice following the blockade of ETAR and ETBR, or only ETBR. Matrix metalloproteinase-9, a tissue-destructive protease involved in early damage, was decreased in the injured spinal cord of mice following blockade of ETAR, ETBR or a combination thereof. The findings of the present study therefore suggested an association between ETAR and ETBR in regulating early pathogenesis of SCI and determining the outcomes of long‑term neurological recovery.
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Affiliation(s)
- Jian Guo
- Department of Orthopaedic Surgery, Ningbo Beilun People Hospital, Ningbo, Zhejiang 315800, P.R. China
| | - Yiqiao Li
- Central Laboratory, Ningbo Beilun People Hospital, Ningbo, Zhejiang 315800, P.R. China
| | - Zhennian He
- Department of Orthopaedic Surgery, Ningbo Beilun People Hospital, Ningbo, Zhejiang 315800, P.R. China
| | - Bin Zhang
- Department of Orthopaedic Surgery, Ningbo Beilun People Hospital, Ningbo, Zhejiang 315800, P.R. China
| | - Yonghuan Li
- Department of Orthopaedic Surgery, Ningbo Beilun People Hospital, Ningbo, Zhejiang 315800, P.R. China
| | - Jianghua Hu
- Department of Orthopaedic Surgery, Ningbo Beilun People Hospital, Ningbo, Zhejiang 315800, P.R. China
| | - Mingyuan Han
- Department of Orthopaedic Surgery, Ningbo Beilun People Hospital, Ningbo, Zhejiang 315800, P.R. China
| | - Yuanlin Xu
- Department of Orthopaedic Surgery, Ningbo Beilun People Hospital, Ningbo, Zhejiang 315800, P.R. China
| | - Yongfu Li
- Department of Orthopaedic Surgery, Ningbo Beilun People Hospital, Ningbo, Zhejiang 315800, P.R. China
| | - Jie Gu
- Department of Orthopaedic Surgery, Ningbo Beilun People Hospital, Ningbo, Zhejiang 315800, P.R. China
| | - Bo Dai
- Department of Orthopaedic Surgery, Ningbo Beilun People Hospital, Ningbo, Zhejiang 315800, P.R. China
| | - Zhong Chen
- Department of Orthopaedic Surgery, The First Affiliated Hospital of College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310000, P.R. China
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The role of pericytes in neurovascular unit remodeling in brain disorders. Int J Mol Sci 2014; 15:6453-74. [PMID: 24743889 PMCID: PMC4013640 DOI: 10.3390/ijms15046453] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 04/01/2014] [Accepted: 04/08/2014] [Indexed: 12/27/2022] Open
Abstract
Neurons are extremely vulnerable cells that tightly rely on the brain’s highly dynamic and complex vascular network that assures an accurate and adequate distribution of nutrients and oxygen. The neurovascular unit (NVU) couples neuronal activity to vascular function, controls brain homeostasis, and maintains an optimal brain microenvironment adequate for neuronal survival by adjusting blood-brain barrier (BBB) parameters based on brain needs. The NVU is a heterogeneous structure constituted by different cell types that includes pericytes. Pericytes are localized at the abluminal side of brain microvessels and contribute to NVU function. Pericytes play essential roles in the development and maturation of the neurovascular system during embryogenesis and stability during adulthood. Initially, pericytes were described as contractile cells involved in controlling neurovascular tone. However, recent reports have shown that pericytes dynamically respond to stress induced by injury upon brain diseases, by chemically and physically communicating with neighboring cells, by their immune properties and by their potential pluripotent nature within the neurovascular niche. As such, in this paper, we would like to review the role of pericytes in NVU remodeling, and their potential as targets for NVU repair strategies and consequently neuroprotection in two pathophysiologically distinct brain disorders: ischemic stroke and Alzheimer’s disease (AD).
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35
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Østergaard L, Aamand R, Karabegovic S, Tietze A, Blicher JU, Mikkelsen IK, Iversen NK, Secher N, Engedal TS, Anzabi M, Jimenez EG, Cai C, Koch KU, Naess-Schmidt ET, Obel A, Juul N, Rasmussen M, Sørensen JCH. The role of the microcirculation in delayed cerebral ischemia and chronic degenerative changes after subarachnoid hemorrhage. J Cereb Blood Flow Metab 2013; 33:1825-37. [PMID: 24064495 PMCID: PMC3851911 DOI: 10.1038/jcbfm.2013.173] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Revised: 08/31/2013] [Accepted: 09/08/2013] [Indexed: 02/07/2023]
Abstract
The mortality after aneurysmal subarachnoid hemorrhage (SAH) is 50%, and most survivors suffer severe functional and cognitive deficits. Half of SAH patients deteriorate 5 to 14 days after the initial bleeding, so-called delayed cerebral ischemia (DCI). Although often attributed to vasospasms, DCI may develop in the absence of angiographic vasospasms, and therapeutic reversal of angiographic vasospasms fails to improve patient outcome. The etiology of chronic neurodegenerative changes after SAH remains poorly understood. Brain oxygenation depends on both cerebral blood flow (CBF) and its microscopic distribution, the so-called capillary transit time heterogeneity (CTH). In theory, increased CTH can therefore lead to tissue hypoxia in the absence of severe CBF reductions, whereas reductions in CBF, paradoxically, improve brain oxygenation if CTH is critically elevated. We review potential sources of elevated CTH after SAH. Pericyte constrictions in relation to the initial ischemic episode and subsequent oxidative stress, nitric oxide depletion during the pericapillary clearance of oxyhemoglobin, vasogenic edema, leukocytosis, and astrocytic endfeet swelling are identified as potential sources of elevated CTH, and hence of metabolic derangement, after SAH. Irreversible changes in capillary morphology and function are predicted to contribute to long-term relative tissue hypoxia, inflammation, and neurodegeneration. We discuss diagnostic and therapeutic implications of these predictions.
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Affiliation(s)
- Leif Østergaard
- 1] Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark [2] Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus, Denmark
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36
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Ji BS, Cen J, He L, Liu M, Liu YQ, Liu L. Modulation of P-glycoprotein in rat brain microvessel endothelial cells under oxygen glucose deprivation. J Pharm Pharmacol 2013; 65:1508-17. [DOI: 10.1111/jphp.12122] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 07/04/2013] [Indexed: 11/30/2022]
Abstract
Abstract
Objectives
To investigate modulation of P-glycoprotein (P-gp) in rat brain microvessel endothelial cells (rBMECs) under oxygen glucose deprivation (OGD).
Methods
The coculture of rBMECs and astrocytes was established to investigate the time course of P-gp, tumour necrosis factor-α (TNF-α), endothelin-1 (ET-1), nitric oxide synthase (NOS) and protein kinase C (PKC) expression in the rBMECs as well as rhodamine 123 (Rh123) transendothelial transfer under OGD using Western blot and HPLC, respectively. The influence of pharmacological tools including H398, JKC-301, RES-701-1, L-NMMA, BIM and SN50 on the P-gp expression as well as Rh123 transendothelial transfer was evaluated at 3 h time point of OGD.
Key findings
Elevated P-gp, TNF-α, ET-1, NOS and PKC expression in the rBMECs, as well as increased P-gp efflux activity were observed after 2 h or more time of OGD. Incubation of H398 and other pharmacological tools downregulated P-gp expression and functional activity in the rBMECs at 3 h time point of OGD.
Conclusions
This report suggested that TNF-α, ET-1, NOS and PKC may mediate upregulation of P-gp in the rBMECs under OGD, which may be worthy of being referenced for the investigation of P-gp at the blood–brain barrier in the early period of stroke.
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Affiliation(s)
- Bian-Sheng Ji
- Key Laboratory of Natural Medicine and Immune Engineering, Henan University, Kaifeng, China
| | - Juan Cen
- Key Laboratory of Natural Medicine and Immune Engineering, Henan University, Kaifeng, China
| | - Ling He
- Department of Pharmacology, China Pharmaceutical University, Nanjing, China
| | - Meng Liu
- Key Laboratory of Natural Medicine and Immune Engineering, Henan University, Kaifeng, China
| | - Yan-Qing Liu
- Key Laboratory of Natural Medicine and Immune Engineering, Henan University, Kaifeng, China
| | - Lu Liu
- Key Laboratory of Natural Medicine and Immune Engineering, Henan University, Kaifeng, China
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Borysova L, Wray S, Eisner DA, Burdyga T. How calcium signals in myocytes and pericytes are integrated across in situ microvascular networks and control microvascular tone. Cell Calcium 2013; 54:163-74. [PMID: 23867002 PMCID: PMC3775125 DOI: 10.1016/j.ceca.2013.06.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 05/30/2013] [Accepted: 06/01/2013] [Indexed: 11/16/2022]
Abstract
The microcirculation is the site of gas and nutrient exchange. Control of central or local signals acting on the myocytes, pericytes and endothelial cells within it, is essential for health. Due to technical problems of accessibility, the mechanisms controlling Ca2+ signalling and contractility of myocytes and pericytes in different sections of microvascular networks in situ have not been investigated. We aimed to investigate Ca2+ signalling and functional responses, in a microcirculatory network in situ. Using live confocal imaging of ureteric microvascular networks, we have studied the architecture, morphology, Ca2+ signalling and contractility of myocytes and pericytes. Ca2+ signals vary between distributing arcade and downstream transverse and precapillary arterioles, are modified by agonists, with sympathetic agonists being ineffective beyond transverse arterioles. In myocytes and pericytes, Ca2+ signals arise from Ca2+ release from the sarcoplasmic reticulum through inositol 1,4,5-trisphosphate-induced Ca2+ release and not via ryanodine receptors or Ca2+ entry into the cell. The responses in pericytes are less oscillatory, slower and longer-lasting than those in myocytes. Myocytes and pericytes are electrically coupled, transmitting Ca2+ signals between arteriolar and venular networks dependent on gap junctions and Ca2+ entry via L-type Ca2+ channels. Endothelial Ca2+ signalling inhibits intracellular Ca2+ oscillations in myocytes and pericytes via L-arginine/nitric oxide pathway and intercellular propagating Ca2+ signals via EDHF. Increases of Ca2+ in pericytes and myocytes constrict all vessels except capillaries. These data reveal the structural and signalling specializations allowing blood flow to be regulated by myocytes and pericytes.
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Affiliation(s)
- Lyudmyla Borysova
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, L69 3BX, UK
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38
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Baburamani AA, Ek CJ, Walker DW, Castillo-Melendez M. Vulnerability of the developing brain to hypoxic-ischemic damage: contribution of the cerebral vasculature to injury and repair? Front Physiol 2012; 3:424. [PMID: 23162470 PMCID: PMC3493883 DOI: 10.3389/fphys.2012.00424] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 10/17/2012] [Indexed: 11/13/2022] Open
Abstract
As clinicians attempt to understand the underlying reasons for the vulnerability of different regions of the developing brain to injury, it is apparent that little is known as to how hypoxia-ischemia may affect the cerebrovasculature in the developing infant. Most of the research investigating the pathogenesis of perinatal brain injury following hypoxia-ischemia has focused on excitotoxicity, oxidative stress and an inflammatory response, with the response of the developing cerebrovasculature receiving less attention. This is surprising as the presentation of devastating and permanent injury such as germinal matrix-intraventricular haemorrhage (GM-IVH) and perinatal stroke are of vascular origin, and the origin of periventricular leukomalacia (PVL) may also arise from poor perfusion of the white matter. This highlights that cerebrovasculature injury following hypoxia could primarily be responsible for the injury seen in the brain of many infants diagnosed with hypoxic-ischemic encephalopathy (HIE). Interestingly the highly dynamic nature of the cerebral blood vessels in the fetus, and the fluctuations of cerebral blood flow and metabolic demand that occur following hypoxia suggest that the response of blood vessels could explain both regional protection and vulnerability in the developing brain. However, research into how blood vessels respond following hypoxia-ischemia have mostly been conducted in adult models of ischemia or stroke, further highlighting the need to investigate how the developing cerebrovasculature responds and the possible contribution to perinatal brain injury following hypoxia. This review discusses the current concepts on the pathogenesis of perinatal brain injury, the development of the fetal cerebrovasculature and the blood brain barrier (BBB), and key mediators involved with the response of cerebral blood vessels to hypoxia.
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Affiliation(s)
- Ana A Baburamani
- The Ritchie Centre, Monash Medical Centre, Monash Institute of Medical Research, Clayton Melbourne, VIC, Australia ; Sahlgrenska Academy, Gothenburg University Göteborg, Sweden
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Østergaard L, Aamand R, Gutiérrez-Jiménez E, Ho YCL, Blicher JU, Madsen SM, Nagenthiraja K, Dalby RB, Drasbek KR, Møller A, Brændgaard H, Mouridsen K, Jespersen SN, Jensen MS, West MJ. The capillary dysfunction hypothesis of Alzheimer's disease. Neurobiol Aging 2012; 34:1018-31. [PMID: 23084084 DOI: 10.1016/j.neurobiolaging.2012.09.011] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2012] [Revised: 08/17/2012] [Accepted: 09/07/2012] [Indexed: 12/21/2022]
Abstract
It is widely accepted that hypoperfusion and changes in capillary morphology are involved in the etiopathogenesis of Alzheimer's disease (AD). This is difficult to reconcile with the hyperperfusion observed in young high-risk subjects. Differences in the way cerebral blood flow (CBF) is coupled with the local metabolic needs during different phases of the disease can explain this apparent paradox. This review describes this coupling in terms of a model of cerebral oxygen availability that takes into consideration the heterogeneity of capillary blood flow patterns. The model predicts that moderate increases in heterogeneity requires elevated CBF in order to maintain adequate oxygenation. However, with progressive increases in heterogeneity, the resulting low tissue oxygen tension will require a suppression of CBF in order to maintain tissue metabolism. The observed biphasic nature of CBF responses in preclinical AD and AD is therefore consistent with progressive disturbances of capillary flow patterns. Salient features of the model are discussed in the context of AD pathology along with potential sources of increased capillary flow heterogeneity.
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Affiliation(s)
- Leif Østergaard
- Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus, Denmark.
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Abstract
While it has been widely confirmed that cerebral blood flow is closely coupled with brain metabolism, it remains a matter of controversy whether capillary flow is directly controlled to meet the energy demands of the parenchyma. Since the capillary is known to lack smooth muscle cells, it has generally been considered that capillary flow is not regulated in situ. However, we now have increasing data supporting the physiological control of capillary flow. The observation of heterogeneity in the microcirculation in vivo has suggested that intravascular factors may be involved in the flow control, including non-Newtonian rheology, red blood cell flow, leukocyte adhesion, release of vasoactive mediators, and expression of glycoproteins on the endothelial cells. Astrocytes, a key mediator of the neurovascular unit, and intrinsic innervation may also regulate capillary flow. In addition, recent findings on pericyte contractility have attracted the attention of many researchers. Finally, based on these findings, we present a new model of flow control, the proximal integration model, in which localized neural activity is detected at nearby capillaries and the vasodilation signal is transmitted proximally along the vessel. Signals are then integrated at the precapillary arterioles and other arterioles further upstream and regulate the capillary flow.
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41
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Dore-Duffy P, Wang S, Mehedi A, Katyshev V, Cleary K, Tapper A, Reynolds C, Ding Y, Zhan P, Rafols J, Kreipke CW. Pericyte-mediated vasoconstriction underlies TBI-induced hypoperfusion. Neurol Res 2012; 33:176-86. [PMID: 21801592 DOI: 10.1179/016164111x12881719352372] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVES Endothelin-1 is a 21-amino acid peptide that together with specific receptors, A (ETrA) and B (ETrB) is induced following traumatic brain injury (TBI) and has been closely linked to regulation of cerebral vasospasm, oxidative stress, and hypoperfusion. Specific endothelin receptor antagonists have been shown to ameliorate early evidence of neuronal cell injury, activation of microglial cells, and hypoperfusion following TBI. The exact mechanism involved in TBI-induced hypoperfusion is still unclear; however, it is thought that endothelin-1 engagement of ETrA is primarily responsible for changes in blood flow. In this study we question the role of the microvascular pericyte in endothelin-1-mediated pathophysiology in TBI. METHODS Pericyte expression of endothelin-1, ETrA, and ETrB was examined in primary culture and in sham and impacted rat brain. Adult male rats were also given intracerebroventricular injections of ETrA (BQ-123) before being subjected to TBI using a closed head acceleration impact model. RESULTS Primary pericytes express both endothelin-1 and its receptors ETrA and ETrB. Following TBI, the number of alpha-smooth muscle actin (SMA) positive pericytes located in microvessels is significantly increased by 4 hours post-traumatic impact. Increases in pericyte expression of alpha-SMA correlated with evidence of a reduction in both arteriolar and capillary diameter. Capillary endothelin-1, ETrA, and ETrB transcript and protein was also increased. Increased endothelin-1 expression was seen by 2-4 hours post-impact. Upregulation of receptors was observed by 4-8 hours and maximum by 24 hours. ETrA antagonists decreased the number of alpha-SMA(+) pericytes as well as changes in microvascular diameter. CONCLUSION These results suggest that decreased vasoconstriction following TBI may be due to an endothelin-1-induced pericyte-mediated regulation of microvessel blood flow following TBI. Furthermore, results suggest that ETrA antagonists ameliorate trauma induced hypoperfusion, in part, by inhibiting endothelin-1-mediated upregulation of alpha-SMA in pericytes.
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Affiliation(s)
- Paula Dore-Duffy
- Department of Neurology, Wayne State University School of Medicine, Detroit, MI 48201, USA.
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The role of amino acid transporters in GSH synthesis in the blood-brain barrier and central nervous system. Neurochem Int 2012; 61:405-14. [PMID: 22634224 DOI: 10.1016/j.neuint.2012.05.019] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 04/17/2012] [Accepted: 05/15/2012] [Indexed: 12/22/2022]
Abstract
Glutathione (GSH) plays a critical role in protecting cells from oxidative stress and xenobiotics, as well as maintaining the thiol redox state, most notably in the central nervous system (CNS). GSH concentration and synthesis are highly regulated within the CNS and are limited by availability of the sulfhydryl amino acid (AA) l-cys, which is mainly transported from the blood, through the blood-brain barrier (BBB), and into neurons. Several antiporter transport systems (e.g., x(c)(-), x(-)(AG), and L) with clearly different luminal and abluminal distribution, Na(+), and pH dependency have been described in brain endothelial cells (BEC) of the BBB, as well as in neurons, astrocytes, microglia and oligodendrocytes from different brain structures. The purpose of this review is to summarize information regarding the different AA transport systems for l-cys and its oxidized form l-cys(2) in the CNS, such as expression and activity in blood-brain barrier endothelial cells, astrocytes and neurons and environmental factors that modulate transport kinetics.
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Reijerkerk A, Lakeman KAM, Drexhage JAR, van Het Hof B, van Wijck Y, van der Pol SMA, Kooij G, Geerts D, de Vries HE. Brain endothelial barrier passage by monocytes is controlled by the endothelin system. J Neurochem 2011; 121:730-7. [PMID: 21777246 DOI: 10.1111/j.1471-4159.2011.07393.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Homeostasis of the brain is dependent on the blood-brain barrier (BBB). This barrier tightly regulates the exchange of essential nutrients and limits the free flow of immune cells into the CNS. Perturbations of BBB function and the loss of its immune quiescence are hallmarks of a variety of brain diseases, including multiple sclerosis (MS), vascular dementia, and stroke. In particular, diapedesis of monocytes and subsequent trafficking of monocyte-derived macrophages into the brain are key mediators of demyelination and axonal damage in MS. Endothelin-1 (ET-1) is considered as a potent pro-inflammatory peptide and has been implicated in the development of cardiovascular diseases. Here, we studied the role of different components of the endothelin system, i.e., ET-1, its type B receptor (ET(B)) and endothelin-converting enzyme-1 (ECE-1) in monocyte diapedesis of a human brain endothelial cell barrier. Our pharmacological inhibitory and specific gene knockdown studies point to a regulatory function of these proteins in transendothelial passage of monocytes. Results from this study suggest that the endothelin system is a putative target within the brain for anti-inflammatory treatment in neurological diseases.
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Affiliation(s)
- Arie Reijerkerk
- Blood-brain barrier Research Group, Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, The Netherlands.
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Brain microvascular pericytes in health and disease. Acta Neuropathol 2011; 122:1-9. [PMID: 21656168 DOI: 10.1007/s00401-011-0847-6] [Citation(s) in RCA: 148] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 05/31/2011] [Accepted: 05/31/2011] [Indexed: 12/19/2022]
Abstract
Pericytes are located at periphery of the microvessel wall and wrap it with their processes. They communicate with other cells of the neurovascular unit by direct contact or through signaling pathways and regulate several important microcirculatory functions. These include development and maintenance of the blood-brain barrier (BBB), distribution of the capillary blood flow to match the local metabolic need of the nearby cells, and angiogenesis. Pericytes also exhibit phagocytic activity and may function as pluripotent stem cells. Increasing evidence suggests a role for pericytes in a wide range of CNS diseases. They appear to be vulnerable to oxygen and nitrogen radical toxicity and have been shown to contract during cerebral ischemia and remain contracted despite reopening of the occluded artery. This causes impaired re-flow and may diminish the benefit of re-canalization therapies in stroke patients. Hyperglycemia-induced dysfunction of the signaling pathways between pericytes and endothelia is thought to play an important role in diabetic retinopathy, a common cause of blindness. Amyloid deposits detected within degenerating pericytes in the brains of patients with Alzheimer's disease suggest that pericyte dysfunction may play a role in cerebral hypoperfusion and impaired amyloid β-peptide clearance in Alzheimer's disease. This exciting possibility may reveal a novel temporal sequence of events in chronic neurodegeneration, in which microvascular dysfunction due to pericyte degeneration initiates secondary neurodegenerative changes. Identification of molecular mechanisms by which pericytes regulate BBB integrity in inflammatory conditions as well as in vasogenic brain edema may lead to new treatments. Pericytes may also take part in tissue repair and vascularization after CNS injury. In conclusion, although the evidence is just emerging and mostly preliminary, disclosing pericytes' role in the pathophysiology of CNS diseases may yield exciting developments and novel treatments.
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Abstract
ET (endothelin)-1 was first described as a potent vasoconstrictor. Since then, many other deleterious properties mediated via its two receptors, ETA and ETB, have been described, such as inflammation, fibrosis and hyperplasia. These effects, combined with a wide tissue distribution of the ET system, its up-regulation in pathological situations and a local autocrine/paracrine activity due to a high tissue receptor binding, make the tissue ET system a key local player in end-organ damage. Furthermore, ET-1 interacts in tissues with other systems such as the RAAS (renin-angiotensin-aldosterone system) to exert its effects. In numerous genetically modified animal models, non-specific or organ-targeted ET-1 overexpression causes intense organ damage, especially hypertrophy and fibrosis, in the absence of haemodynamic changes, confirming a local activity of the ET system. ET receptor antagonists have been shown to prevent and sometimes reverse these tissue alterations in an organ-specific manner, leading to long-term benefits and an improvement in survival in different animal models. Potential for such benefits going beyond a pure haemodynamic effect have also been suggested by clinical trial results in which ET receptor antagonism decreased the occurrence of new digital ulcers in patients with systemic sclerosis and delayed the time to clinical worsening in patients with PAH (pulmonary arterial hypertension). The tissue ET system allows therapeutic interventions to provide organ selectivity and beneficial effects in diseases associated with tissue inflammation, hypertrophy or fibrosis.
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Hamilton NB, Attwell D, Hall CN. Pericyte-mediated regulation of capillary diameter: a component of neurovascular coupling in health and disease. FRONTIERS IN NEUROENERGETICS 2010; 2. [PMID: 20725515 PMCID: PMC2912025 DOI: 10.3389/fnene.2010.00005] [Citation(s) in RCA: 343] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Accepted: 04/28/2010] [Indexed: 12/18/2022]
Abstract
Because regional blood flow increases in association with the increased metabolic demand generated by localized increases in neural activity, functional imaging researchers often assume that changes in blood flow are an accurate read-out of changes in underlying neural activity. An understanding of the mechanisms that link changes in neural activity to changes in blood flow is crucial for assessing the validity of this assumption, and for understanding the processes that can go wrong during disease states such as ischaemic stroke. Many studies have investigated the mechanisms of neurovascular regulation in arterioles but other evidence suggests that blood flow regulation can also occur in capillaries, because of the presence of contractile cells, pericytes, on the capillary wall. Here we review the evidence that pericytes can modulate capillary diameter in response to neuronal activity and assess the likely importance of neurovascular regulation at the capillary level for functional imaging experiments. We also discuss evidence suggesting that pericytes are particularly sensitive to damage during pathological insults such as ischaemia, Alzheimer's disease and diabetic retinopathy, and consider the potential impact that pericyte dysfunction might have on the development of therapeutic interventions and on the interpretation of functional imaging data in these disorders.
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Affiliation(s)
- Nicola B Hamilton
- Department of Neuroscience, Physiology and Pharmacology, University College London London, UK
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Roh M, Abdulkadir SA. Targeting the endothelin receptor in prostate cancer bone metastasis: Back to the mouse? Cancer Biol Ther 2010; 9:615-7. [PMID: 20150768 DOI: 10.4161/cbt.9.8.11309] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Meejeon Roh
- Department of Pathology, Vanderbilt University Medical Center, Nashville, TN, USA
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Spijkers LJA, Alewijnse AE, Peters SLM. Sphingolipids and the orchestration of endothelium-derived vasoactive factors: when endothelial function demands greasing. Mol Cells 2010; 29:105-11. [PMID: 20127284 DOI: 10.1007/s10059-010-0042-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Accepted: 01/08/2010] [Indexed: 02/02/2023] Open
Abstract
Vasomotor tone is regulated by a complex interplay of a variety of extrinsic neurohumoral and intrinsic factors. It is the endothelium that has a major influence on smooth muscle cell tone via the release of intrinsic vasoactive factors and is therefore an important regulator of vasomotor tone. Sphingolipids are an emerging class of lipid mediators with important physiological properties. In the last two decades it has not only become increasingly clear that sphingolipid signaling plays a pivotal role in immune function, but also its role in the vascular system is now becoming more recognized. In this mini-review we will highlight the possible cross-talk between sphingolipids and intrinsic vasoactive factors released by the endothelium. Via this cross-talk sphingolipids can orchestrate vasomotor tone and may therefore also be involved in the pathophysiology of disease states associated with endothelial dysfunction.
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Affiliation(s)
- Léon J A Spijkers
- Department Pharmacology and Pharmacotherapy, Academic Medical Center, Amsterdam, The Netherlands
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Abstract
Rouget, in 1873, was the first to describe a population of cells surrounding capillaries, which he regarded as contractile elements. Fifty years later, Zimmermann termed these cells "pericytes" and distinguished three subtypes along the vascular tree. Since then, the discussion concerning the contractile ability of pericytes has never ceased. Current concepts of pericyte biology rather suggest critical roles in the maintenance of homeostasis, blood-brain barrier (BBB) integrity, angiogenesis, and neovascularization. In addition, data from models of brain pathology suggest that novel pericytes are recruited from the bone marrow, but their respective precursor remains enigmatic. Recent data also suggest an important role in the regulation of cerebral blood flow, thus confirming Rouget's original idea. However, comparison of data from different studies is often constrained by the fact that pericytes were questionably identified. Although a clear-cut definition exists, defining pericytes as part of the vascular wall being enclosed in its basement membrane, pericytes are often mixed up with adjacent cell types of the vascular wall, the perivascular space, and the juxtavascular parenchyma. In fact, their identification is difficult-if not impossible-in standard histological sections. An unambiguous distinction, however, is possible at the ultrastructural level and in semi-thin sections, where their location within the vascular basement membrane can be displayed. Using these techniques in combination with immunological staining methods allows demarking their unique morphology and location. Here, we review original papers describing pericytes, briefly outline their topography within the vascular compartments, describe methods for their identification, and summarize current concepts of their function.
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Affiliation(s)
- Martin Krueger
- Dr. Senckenbergische Anatomie, Institute of Clinical Neuroanatomy, J W Goethe-University, Frankfurt/Main, Germany
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Oishi K, Kamiyashiki T, Ito Y. Isometric contraction of microvascular pericytes from mouse brain parenchyma. Microvasc Res 2007; 73:20-8. [PMID: 17030042 DOI: 10.1016/j.mvr.2006.08.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2006] [Revised: 08/10/2006] [Accepted: 08/22/2006] [Indexed: 01/10/2023]
Abstract
Pericytes were isolated and cultured from mouse cerebroparenchymal microvessels. A single pericyte clone was three-dimensionally cultured in a collagen gel by adding tensile stress, resulting in the reconstruction of narrow stringy fibers. When the contractility of these fibers was evaluated isometrically, they contracted in response to acetylcholine (ACh)1 or noradrenaline; this was accompanied by an increase in intracellular calcium concentration ([Ca(2+)]i). The fibers that were pre-contracted by ACh were completely relaxed by papaverine, which is a smooth-muscle relaxant. Moreover, the muscarinic ACh receptor-antagonist atropine depressed the [Ca(2+)]i response that was induced by ACh. This study demonstrates for the first time the quantitative measurement of the contractions produced by cultured microvascular pericytes from mouse brain parenchyma.
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Affiliation(s)
- Kazuhiko Oishi
- Department of Pharmacology, Meiji Pharmaceutical University, 2-522-1, Noshio, Kiyose, Tokyo 204-8588, Japan.
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