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Yu X, Ji C, Shao A. Neurovascular Unit Dysfunction and Neurodegenerative Disorders. Front Neurosci 2020; 14:334. [PMID: 32410936 PMCID: PMC7201055 DOI: 10.3389/fnins.2020.00334] [Citation(s) in RCA: 113] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 03/20/2020] [Indexed: 12/11/2022] Open
Abstract
The neurovascular unit (NVU), composed of vascular cells, glial cells, and neurons, is the minimal functional unit of the brain. The NVU maintains integrity of the blood–brain barrier (BBB) and regulates supply of the cerebral blood flow (CBF), both of which are keys to maintaining normal brain function. BBB dysfunction and a decreased CBF are early pathophysiological changes in neurodegenerative disorders, such as Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS). In this review, we primarily focus on the NVU in AD as much research has been performed on the connection between NVU dysfunction and AD. We also discuss the role of NVU dysfunction in the pathophysiological mechanisms of PD and ALS. As most neurodegenerative diseases are difficult to treat, we discuss several potential drug targets that focus on the NVU that may inform novel vascular-targeted therapies for AD, PD, and ALS.
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Affiliation(s)
- Xing Yu
- Department of Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Caihong Ji
- Department of Neurology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Anwen Shao
- Department of Neurosurgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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52
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Uemura MT, Maki T, Ihara M, Lee VMY, Trojanowski JQ. Brain Microvascular Pericytes in Vascular Cognitive Impairment and Dementia. Front Aging Neurosci 2020; 12:80. [PMID: 32317958 PMCID: PMC7171590 DOI: 10.3389/fnagi.2020.00080] [Citation(s) in RCA: 138] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 03/04/2020] [Indexed: 12/19/2022] Open
Abstract
Pericytes are unique, multi-functional mural cells localized at the abluminal side of the perivascular space in microvessels. Originally discovered in 19th century, pericytes had drawn less attention until decades ago mainly due to lack of specific markers. Recently, however, a growing body of evidence has revealed that pericytes play various important roles: development and maintenance of blood–brain barrier (BBB), regulation of the neurovascular system (e.g., vascular stability, vessel formation, cerebral blood flow, etc.), trafficking of inflammatory cells, clearance of toxic waste products from the brain, and acquisition of stem cell-like properties. In the neurovascular unit, pericytes perform these functions through coordinated crosstalk with neighboring cells including endothelial, glial, and neuronal cells. Dysfunction of pericytes contribute to a wide variety of diseases that lead to cognitive impairments such as cerebral small vessel disease (SVD), acute stroke, Alzheimer’s disease (AD), and other neurological disorders. For instance, in SVDs, pericyte degeneration leads to microvessel instability and demyelination while in stroke, pericyte constriction after ischemia causes a no-reflow phenomenon in brain capillaries. In AD, which shares some common risk factors with vascular dementia, reduction in pericyte coverage and subsequent microvascular impairments are observed in association with white matter attenuation and contribute to impaired cognition. Pericyte loss causes BBB-breakdown, which stagnates amyloid β clearance and the leakage of neurotoxic molecules into the brain parenchyma. In this review, we first summarize the characteristics of brain microvessel pericytes, and their roles in the central nervous system. Then, we focus on how dysfunctional pericytes contribute to the pathogenesis of vascular cognitive impairment including cerebral ‘small vessel’ and ‘large vessel’ diseases, as well as AD. Finally, we discuss therapeutic implications for these disorders by targeting pericytes.
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Affiliation(s)
- Maiko T Uemura
- Institute on Aging and Center for Neurodegenerative Disease Research, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States.,JSPS Overseas Research Fellowship Program, Japan Society for the Promotion of Science, Tokyo, Japan
| | - Takakuni Maki
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Masafumi Ihara
- Department of Neurology, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Virginia M Y Lee
- Institute on Aging and Center for Neurodegenerative Disease Research, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - John Q Trojanowski
- Institute on Aging and Center for Neurodegenerative Disease Research, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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53
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Lendahl U, Nilsson P, Betsholtz C. Emerging links between cerebrovascular and neurodegenerative diseases-a special role for pericytes. EMBO Rep 2019; 20:e48070. [PMID: 31617312 PMCID: PMC6831996 DOI: 10.15252/embr.201948070] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 06/11/2019] [Accepted: 06/24/2019] [Indexed: 12/11/2022] Open
Abstract
Neurodegenerative and cerebrovascular diseases cause considerable human suffering, and therapy options for these two disease categories are limited or non-existing. It is an emerging notion that neurodegenerative and cerebrovascular diseases are linked in several ways, and in this review, we discuss the current status regarding vascular dysregulation in neurodegenerative disease, and conversely, how cerebrovascular diseases are associated with central nervous system (CNS) degeneration and dysfunction. The emerging links between neurodegenerative and cerebrovascular diseases are reviewed with a particular focus on pericytes-important cells that ensheath the endothelium in the microvasculature and which are pivotal for blood-brain barrier function and cerebral blood flow. Finally, we address how novel molecular and cellular insights into pericytes and other vascular cell types may open new avenues for diagnosis and therapy development for these important diseases.
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Affiliation(s)
- Urban Lendahl
- Department of Cell and Molecular BiologyKarolinska InstitutetStockholmSweden
- Department of Neurobiology, Care Sciences and SocietyDivision of NeurogeriatricsCenter for Alzheimer ResearchKarolinska InstitutetSolnaSweden
- Integrated Cardio Metabolic Centre (ICMC)HuddingeSweden
| | - Per Nilsson
- Department of Neurobiology, Care Sciences and SocietyDivision of NeurogeriatricsCenter for Alzheimer ResearchKarolinska InstitutetSolnaSweden
| | - Christer Betsholtz
- Integrated Cardio Metabolic Centre (ICMC)HuddingeSweden
- Department of Immunology, Genetics and PathologyRudbeck LaboratoryUppsala UniversityUppsalaSweden
- Department of MedicineKarolinska InstitutetHuddingeSweden
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54
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Zhong J, Guo C, Hou W, Shen N, Miao C. Effects of MFHAS1 on cognitive impairment and dendritic pathology in the hippocampus of septic rats. Life Sci 2019; 235:116822. [PMID: 31476310 DOI: 10.1016/j.lfs.2019.116822] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 08/21/2019] [Accepted: 08/29/2019] [Indexed: 01/31/2023]
Abstract
AIMS To investigate the effects of malignant fibrous histiocytoma amplified sequence 1 (MFHAS1) on cognitive dysfunction, the expression of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and amyloid β peptide (Aβ) in the hippocampus, as well as dendritic pathology in the hippocampal CA1 region in sepsis-associated encephalopathy (SAE) rats. MAIN METHODS The rats were randomly divided into four groups: 1) control group (subjected to sham surgery), 2) control plus Mfhas1 siRNA group (rats received intracerebroventricular injection of Mfhas1 siRNA after sham surgery), 3) CLP plus control siRNA group (rats received intracerebroventricular injection of control siRNA after cecal ligation and puncture (CLP)), 4) CLP plus Mfhas1 siRNA group (rats received intracerebroventricular injection of Mfhas1 siRNA after CLP). The learning and memory capabilities of the rats were examined by means of fear conditioning and Barnes maze test. The concentration of TNF-α and IL-1β was determined by enzyme-linked immunosorbent assay. The efficiency of siRNA transfection, MFHAS1 and Aβ expression were detected by Western blotting. Total branch lengths of pyramidal dendrites of the CA1 basilar trees and spine density were determined by Golgi staining. KEY FINDINGS We observed that MFHAS1 knock-down by Mfhas1 siRNA intracerebroventricular injection could improve cognitive impairment, reduce the expression of TNF-α, IL-1β and Aβ in the hippocampus induced by CLP, and alleviate the dendritic spinal loss of the pyramidal neurons, as well as increase the dendritic branching of the CA1 basilar trees of septic rats. SIGNIFICANCE MFHAS1 knock-down can alleviate cognitive impairment, neuroinflammation and dendritic spinal loss in SAE rats.
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Affiliation(s)
- Jing Zhong
- Department of Anesthesiology, Fudan University Shanghai Cancer Center, Shanghai, China; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Chenyue Guo
- Department of Anesthesiology, Fudan University Shanghai Cancer Center, Shanghai, China; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Wenting Hou
- Department of Anesthesiology, Fudan University Shanghai Cancer Center, Shanghai, China; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Na Shen
- Department of Otolaryngology, Zhongshan Hospital, Fudan University, Shanghai, China.
| | - Changhong Miao
- Department of Anesthesiology, Fudan University Shanghai Cancer Center, Shanghai, China; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.
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55
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Abdul Razzak R, Florence GJ, Gunn-Moore FJ. Approaches to CNS Drug Delivery with a Focus on Transporter-Mediated Transcytosis. Int J Mol Sci 2019; 20:E3108. [PMID: 31242683 PMCID: PMC6627589 DOI: 10.3390/ijms20123108] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 06/15/2019] [Accepted: 06/16/2019] [Indexed: 12/13/2022] Open
Abstract
Drug delivery to the central nervous system (CNS) conferred by brain barriers is a major obstacle in the development of effective neurotherapeutics. In this review, a classification of current approaches of clinical or investigational importance for the delivery of therapeutics to the CNS is presented. This classification includes the use of formulations administered systemically that can elicit transcytosis-mediated transport by interacting with transporters expressed by transvascular endothelial cells. Neurotherapeutics can also be delivered to the CNS by means of surgical intervention using specialized catheters or implantable reservoirs. Strategies for delivering drugs to the CNS have evolved tremendously during the last two decades, yet, some factors can affect the quality of data generated in preclinical investigation, which can hamper the extension of the applications of these strategies into clinically useful tools. Here, we disclose some of these factors and propose some solutions that may prove valuable at bridging the gap between preclinical findings and clinical trials.
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Affiliation(s)
- Rana Abdul Razzak
- Medical and Biological Sciences Building, School of Biology, University of St Andrews, St Andrews KY16 9TF, UK.
- Biomedical Science Research Centre, Schools of Chemistry and Biology, University of St Andrews, St Andrews KY16 9TF, UK.
| | - Gordon J Florence
- Biomedical Science Research Centre, Schools of Chemistry and Biology, University of St Andrews, St Andrews KY16 9TF, UK.
| | - Frank J Gunn-Moore
- Medical and Biological Sciences Building, School of Biology, University of St Andrews, St Andrews KY16 9TF, UK.
- Biomedical Science Research Centre, Schools of Chemistry and Biology, University of St Andrews, St Andrews KY16 9TF, UK.
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56
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Ryan L, Hay M, Huentelman MJ, Duarte A, Rundek T, Levin B, Soldan A, Pettigrew C, Mehl MR, Barnes CA. Precision Aging: Applying Precision Medicine to the Field of Cognitive Aging. Front Aging Neurosci 2019; 11:128. [PMID: 31231204 PMCID: PMC6568195 DOI: 10.3389/fnagi.2019.00128] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 05/16/2019] [Indexed: 12/13/2022] Open
Abstract
The current "one size fits all" approach to our cognitive aging population is not adequate to close the gap between cognitive health span and lifespan. In this review article, we present a novel model for understanding, preventing, and treating age-related cognitive impairment (ARCI) based on concepts borrowed from precision medicine. We will discuss how multiple risk factors can be classified into risk categories because of their interrelatedness in real life, the genetic variants that increase sensitivity to, or ameliorate, risk for ARCI, and the brain drivers or common mechanisms mediating brain aging. Rather than providing a definitive model of risk for ARCI and cognitive decline, the Precision Aging model is meant as a starting point to guide future research. To that end, after briefly discussing key risk categories, genetic risks, and brain drivers, we conclude with a discussion of steps that must be taken to move the field forward.
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Affiliation(s)
- Lee Ryan
- Department of Psychology, College of Science, University of Arizona, Tucson, AZ, United States
| | - Meredith Hay
- Department of Physiology, University of Arizona, Tucson, AZ, United States
| | - Matt J. Huentelman
- Neurobehavioral Research Unit, Division of Neurological Disorders, Translational Genomics Research Institute (TGen), Phoenix, AZ, United States
| | - Audrey Duarte
- Center for Advanced Brain Imaging, School of Psychology, Georgia Institute of Technology, Atlanta, GA, United States
| | - Tatjana Rundek
- Clinical and Translational Research Division, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Bonnie Levin
- Neuropsychology Division, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Anja Soldan
- Department of Neurology, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Corinne Pettigrew
- Department of Neurology, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Matthias R. Mehl
- Department of Psychology, College of Science, University of Arizona, Tucson, AZ, United States
| | - Carol A. Barnes
- Department of Psychology, College of Science, University of Arizona, Tucson, AZ, United States
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57
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Govindpani K, McNamara LG, Smith NR, Vinnakota C, Waldvogel HJ, Faull RL, Kwakowsky A. Vascular Dysfunction in Alzheimer's Disease: A Prelude to the Pathological Process or a Consequence of It? J Clin Med 2019; 8:E651. [PMID: 31083442 PMCID: PMC6571853 DOI: 10.3390/jcm8050651] [Citation(s) in RCA: 122] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 04/29/2019] [Accepted: 05/06/2019] [Indexed: 12/19/2022] Open
Abstract
Alzheimer's disease (AD) is the most prevalent form of dementia. Despite decades of research following several theoretical and clinical lines, all existing treatments for the disorder are purely symptomatic. AD research has traditionally been focused on neuronal and glial dysfunction. Although there is a wealth of evidence pointing to a significant vascular component in the disease, this angle has been relatively poorly explored. In this review, we consider the various aspects of vascular dysfunction in AD, which has a significant impact on brain metabolism and homeostasis and the clearance of β-amyloid and other toxic metabolites. This may potentially precede the onset of the hallmark pathophysiological and cognitive symptoms of the disease. Pathological changes in vessel haemodynamics, angiogenesis, vascular cell function, vascular coverage, blood-brain barrier permeability and immune cell migration may be related to amyloid toxicity, oxidative stress and apolipoprotein E (APOE) genotype. These vascular deficits may in turn contribute to parenchymal amyloid deposition, neurotoxicity, glial activation and metabolic dysfunction in multiple cell types. A vicious feedback cycle ensues, with progressively worsening neuronal and vascular pathology through the course of the disease. Thus, a better appreciation for the importance of vascular dysfunction in AD may open new avenues for research and therapy.
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Affiliation(s)
- Karan Govindpani
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Laura G McNamara
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Nicholas R Smith
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Chitra Vinnakota
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Henry J Waldvogel
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Richard Lm Faull
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Andrea Kwakowsky
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
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Sweeney MD, Zhao Z, Montagne A, Nelson AR, Zlokovic BV. Blood-Brain Barrier: From Physiology to Disease and Back. Physiol Rev 2019; 99:21-78. [PMID: 30280653 PMCID: PMC6335099 DOI: 10.1152/physrev.00050.2017] [Citation(s) in RCA: 1207] [Impact Index Per Article: 241.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 04/17/2018] [Accepted: 04/17/2018] [Indexed: 12/12/2022] Open
Abstract
The blood-brain barrier (BBB) prevents neurotoxic plasma components, blood cells, and pathogens from entering the brain. At the same time, the BBB regulates transport of molecules into and out of the central nervous system (CNS), which maintains tightly controlled chemical composition of the neuronal milieu that is required for proper neuronal functioning. In this review, we first examine molecular and cellular mechanisms underlying the establishment of the BBB. Then, we focus on BBB transport physiology, endothelial and pericyte transporters, and perivascular and paravascular transport. Next, we discuss rare human monogenic neurological disorders with the primary genetic defect in BBB-associated cells demonstrating the link between BBB breakdown and neurodegeneration. Then, we review the effects of genes underlying inheritance and/or increased susceptibility for Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease, and amyotrophic lateral sclerosis (ALS) on BBB in relation to other pathologies and neurological deficits. We next examine how BBB dysfunction relates to neurological deficits and other pathologies in the majority of sporadic AD, PD, and ALS cases, multiple sclerosis, other neurodegenerative disorders, and acute CNS disorders such as stroke, traumatic brain injury, spinal cord injury, and epilepsy. Lastly, we discuss BBB-based therapeutic opportunities. We conclude with lessons learned and future directions, with emphasis on technological advances to investigate the BBB functions in the living human brain, and at the molecular and cellular level, and address key unanswered questions.
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Affiliation(s)
- Melanie D Sweeney
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California , Los Angeles, California ; and Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California , Los Angeles, California
| | - Zhen Zhao
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California , Los Angeles, California ; and Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California , Los Angeles, California
| | - Axel Montagne
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California , Los Angeles, California ; and Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California , Los Angeles, California
| | - Amy R Nelson
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California , Los Angeles, California ; and Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California , Los Angeles, California
| | - Berislav V Zlokovic
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California , Los Angeles, California ; and Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California , Los Angeles, California
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59
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Ma Q, Zhao Z, Sagare AP, Wu Y, Wang M, Owens NC, Verghese PB, Herz J, Holtzman DM, Zlokovic BV. Blood-brain barrier-associated pericytes internalize and clear aggregated amyloid-β42 by LRP1-dependent apolipoprotein E isoform-specific mechanism. Mol Neurodegener 2018; 13:57. [PMID: 30340601 PMCID: PMC6194676 DOI: 10.1186/s13024-018-0286-0] [Citation(s) in RCA: 165] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 10/01/2018] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Clearance at the blood-brain barrier (BBB) plays an important role in removal of Alzheimer's amyloid-β (Aβ) toxin from brain both in humans and animal models. Apolipoprotein E (apoE), the major genetic risk factor for AD, disrupts Aβ clearance at the BBB. The cellular and molecular mechanisms, however, still remain unclear, particularly whether the BBB-associated brain capillary pericytes can contribute to removal of aggregated Aβ from brain capillaries, and whether removal of Aβ aggregates by pericytes requires apoE, and if so, is Aβ clearance on pericytes apoE isoform-specific. METHODS We performed immunostaining for Aβ and pericyte biomarkers on brain capillaries (< 6 μm in diameter) on tissue sections derived from AD patients and age-matched controls, and APPSwe/0 mice and littermate controls. Human Cy3-Aβ42 uptake by pericytes was studied on freshly isolated brain slices from control mice, pericyte LRP1-deficient mice (Lrplox/lox;Cspg4-Cre) and littermate controls. Clearance of aggregated Aβ42 by mouse pericytes was studied on multi-spot glass slides under different experimental conditions including pharmacologic and/or genetic inhibition of the low density lipoprotein receptor related protein 1 (LRP1), an apoE receptor, and/or silencing mouse endogenous Apoe in the presence and absence of human astrocyte-derived lipidated apoE3 or apoE4. Student's t-test and one-way ANOVA followed by Bonferroni's post-hoc test were used for statistical analysis. RESULTS First, we found that 35% and 60% of brain capillary pericytes accumulate Aβ in AD patients and 8.5-month-old APPSw/0 mice, respectively, compared to negligible uptake in controls. Cy3-Aβ42 species were abundantly taken up by pericytes on cultured mouse brain slices via LRP1, as shown by both pharmacologic and genetic inhibition of LRP1 in pericytes. Mouse pericytes vigorously cleared aggregated Cy3-Aβ42 from multi-spot glass slides via LRP1, which was inhibited by pharmacologic and/or genetic knockdown of mouse endogenous apoE. Human astrocyte-derived lipidated apoE3, but not apoE4, normalized Aβ42 clearance by mouse pericytes with silenced mouse apoE. CONCLUSIONS Our data suggest that BBB-associated pericytes clear Aβ aggregates via an LRP1/apoE isoform-specific mechanism. These data support the role of LRP1/apoE interactions on pericytes as a potential therapeutic target for controlling Aβ clearance in AD.
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Affiliation(s)
- Qingyi Ma
- Center for Neurodegeneration and Regeneration, Zilkha Neurogenetic Institute and Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California 90033 USA
- Lawrence D. Longo, MD Center for Neonatal Biology, Division of Pharmacology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA 92350 USA
| | - Zhen Zhao
- Center for Neurodegeneration and Regeneration, Zilkha Neurogenetic Institute and Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California 90033 USA
| | - Abhay P Sagare
- Center for Neurodegeneration and Regeneration, Zilkha Neurogenetic Institute and Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California 90033 USA
| | - Yingxi Wu
- Center for Neurodegeneration and Regeneration, Zilkha Neurogenetic Institute and Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California 90033 USA
| | - Min Wang
- Center for Neurodegeneration and Regeneration, Zilkha Neurogenetic Institute and Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California 90033 USA
| | - Nelly Chuqui Owens
- Center for Neurodegeneration and Regeneration, Zilkha Neurogenetic Institute and Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California 90033 USA
| | | | - Joachim Herz
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX USA
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX USA
- Department of Neurology and Neurotherapeutics and Center for Translational Neurodegeneration Research, University of Texas Southwestern Medical Center, Dallas, TX USA
| | - David M Holtzman
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer’s Disease Research Center, Washington University School of Medicine, Saint Louis, MO 63110 USA
| | - Berislav V Zlokovic
- Center for Neurodegeneration and Regeneration, Zilkha Neurogenetic Institute and Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California 90033 USA
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Castro PR, Barbosa AS, Pereira JM, Ranfley H, Felipetto M, Gonçalves CAX, Paiva IR, Berg BB, Barcelos LS. Cellular and Molecular Heterogeneity Associated with Vessel Formation Processes. BIOMED RESEARCH INTERNATIONAL 2018; 2018:6740408. [PMID: 30406137 PMCID: PMC6199857 DOI: 10.1155/2018/6740408] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Accepted: 09/06/2018] [Indexed: 12/11/2022]
Abstract
The microvasculature heterogeneity is a complex subject in vascular biology. The difficulty of building a dynamic and interactive view among the microenvironments, the cellular and molecular heterogeneities, and the basic aspects of the vessel formation processes make the available knowledge largely fragmented. The neovascularisation processes, termed vasculogenesis, angiogenesis, arteriogenesis, and lymphangiogenesis, are important to the formation and proper functioning of organs and tissues both in the embryo and the postnatal period. These processes are intrinsically related to microvascular cells, such as endothelial and mural cells. These cells are able to adjust their activities in response to the metabolic and physiological requirements of the tissues, by displaying a broad plasticity that results in a significant cellular and molecular heterogeneity. In this review, we intend to approach the microvasculature heterogeneity in an integrated view considering the diversity of neovascularisation processes and the cellular and molecular heterogeneity that contribute to microcirculatory homeostasis. For that, we will cover their interactions in the different blood-organ barriers and discuss how they cooperate in an integrated regulatory network that is controlled by specific molecular signatures.
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Affiliation(s)
- Pollyana Ribeiro Castro
- Department of Physiology and Biophysics, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais (UFMG), Brazil
| | - Alan Sales Barbosa
- Department of Physiology and Biophysics, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais (UFMG), Brazil
| | - Jousie Michel Pereira
- Department of Physiology and Biophysics, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais (UFMG), Brazil
| | - Hedden Ranfley
- Department of Physiology and Biophysics, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais (UFMG), Brazil
| | - Mariane Felipetto
- Department of Physiology and Biophysics, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais (UFMG), Brazil
| | - Carlos Alberto Xavier Gonçalves
- Department of Biochemistry and Immunology, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais (UFMG), Brazil
| | - Isabela Ribeiro Paiva
- Department of Pharmacology, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais (UFMG), Brazil
| | - Bárbara Betônico Berg
- Department of Pharmacology, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais (UFMG), Brazil
| | - Luciola Silva Barcelos
- Department of Physiology and Biophysics, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais (UFMG), Brazil
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61
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Carvalho C, Moreira PI. Oxidative Stress: A Major Player in Cerebrovascular Alterations Associated to Neurodegenerative Events. Front Physiol 2018; 9:806. [PMID: 30018565 PMCID: PMC6037979 DOI: 10.3389/fphys.2018.00806] [Citation(s) in RCA: 114] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 06/08/2018] [Indexed: 12/19/2022] Open
Abstract
The brain is one of the most exquisite organs in the body with high metabolic demands, and requires a tight regulation of the surrounding environment. This tight control is exerted by the neurovascular unit (NVU) comprising different cell types, where endothelial cells play the commander-in-chief role. Thus, it is assumable that even slight perturbations in NVU might affect, in some cases irreversibly, brain homeostasis and health. In this line, recent findings support the two-hit vascular hypothesis for neurodegenerative conditions, where vascular dysfunction underlies the development of neurodegenerative diseases, such as Alzheimer’s disease (AD). Knowing that endothelial cells are rich in mitochondria and nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, two major reactive oxygen species (ROS) sources, this review aims to gather information on how oxidative stress is in the front line of vascular alterations observed in brain aging and neurodegenerative conditions, particularly AD. Also, a brief discussion about the therapeutic strategies aimed to protect against cerebrovascular diseases is included.
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Affiliation(s)
- Cristina Carvalho
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - Paula I Moreira
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Laboratory of Physiology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
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62
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The effects of cerebral amyloid angiopathy on integrity of the blood-brain barrier. Neurobiol Aging 2018; 70:70-77. [PMID: 30007166 DOI: 10.1016/j.neurobiolaging.2018.06.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 05/21/2018] [Accepted: 06/04/2018] [Indexed: 12/12/2022]
Abstract
Cerebral amyloid angiopathy (CAA), in which amyloid accumulates predominantly in the walls of arterioles and capillaries, is seen in most patients with Alzheimer disease (AD) and may contribute to compromise of blood-brain barrier (BBB) function seen in AD. We investigated the effects of CAA on BBB integrity by examining the expression of the endothelial marker CD31, basement membrane protein collagen IV (COL4), tight junction protein claudin-5, and fibrinogen, a marker of BBB leakage, by immunohistochemistry in the occipital cortex of autopsy brains with AD and capillary CAA (CAA type 1; n = 8), AD with noncapillary CAA (CAA type 2; n = 10), and AD without CAA (n = 7) compared with elderly controls (n = 10). Given the difference in pathogenesis of capillary and noncapillary CAA, we hypothesize that features of BBB breakdown are observed only in capillary CAA. We found decreased expression of CD31 in AD subjects with CAA types 1 and 2 compared with AD without CAA and an increase in COL4 in AD without CAA compared with controls. Furthermore, there was increased immunoreactivity for fibrinogen in AD with CAA type 1 compared with controls. These findings suggest that capillary CAA is associated with morphologic and possibly physiologic alterations of the neurovascular unit and increased BBB permeability in AD.
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63
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Montagne A, Nikolakopoulou AM, Zhao Z, Sagare AP, Si G, Lazic D, Barnes SR, Daianu M, Ramanathan A, Go A, Lawson EJ, Wang Y, Mack WJ, Thompson PM, Schneider JA, Varkey J, Langen R, Mullins E, Jacobs RE, Zlokovic BV. Pericyte degeneration causes white matter dysfunction in the mouse central nervous system. Nat Med 2018; 24:326-337. [PMID: 29400711 PMCID: PMC5840035 DOI: 10.1038/nm.4482] [Citation(s) in RCA: 271] [Impact Index Per Article: 45.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 01/04/2018] [Indexed: 02/07/2023]
Abstract
Diffuse white-matter disease associated with small-vessel disease and dementia is prevalent in the elderly. The biological mechanisms, however, remain elusive. Using pericyte-deficient mice, magnetic resonance imaging, viral-based tract-tracing, and behavior and tissue analysis, we found that pericyte degeneration disrupted white-matter microcirculation, resulting in an accumulation of toxic blood-derived fibrin(ogen) deposits and blood-flow reductions, which triggered a loss of myelin, axons and oligodendrocytes. This disrupted brain circuits, leading to white-matter functional deficits before neuronal loss occurs. Fibrinogen and fibrin fibrils initiated autophagy-dependent cell death in oligodendrocyte and pericyte cultures, whereas pharmacological and genetic manipulations of systemic fibrinogen levels in pericyte-deficient, but not control mice, influenced the degree of white-matter fibrin(ogen) deposition, pericyte degeneration, vascular pathology and white-matter changes. Thus, our data indicate that pericytes control white-matter structure and function, which has implications for the pathogenesis and treatment of human white-matter disease associated with small-vessel disease.
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Affiliation(s)
- Axel Montagne
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Angeliki M. Nikolakopoulou
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Zhen Zhao
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Abhay P. Sagare
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Gabriel Si
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Divna Lazic
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
- Department of Neurobiology, Institute for Biological Research, University of Belgrade, Belgrade, Republic of Serbia
| | - Samuel R. Barnes
- Biological Imaging Center, Beckman Institute, California Institute of Technology, Pasadena, CA 91101, USA
| | - Madelaine Daianu
- Imaging Genetics Center, Mark & Mary Stevens Neuroimaging & Informatics Institute, University of Southern California, Marina del Rey, CA 90292, USA
| | - Anita Ramanathan
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Ariel Go
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Erica J. Lawson
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Yaoming Wang
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - William J. Mack
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Paul M. Thompson
- Imaging Genetics Center, Mark & Mary Stevens Neuroimaging & Informatics Institute, University of Southern California, Marina del Rey, CA 90292, USA
| | - Julie A. Schneider
- Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL 60612, USA
| | - Jobin Varkey
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Ralf Langen
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Eric Mullins
- Division of Hematology and Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH 45229-3039
| | - Russell E. Jacobs
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
- Biological Imaging Center, Beckman Institute, California Institute of Technology, Pasadena, CA 91101, USA
| | - Berislav V. Zlokovic
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
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64
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Sweeney MD, Sagare AP, Zlokovic BV. Blood-brain barrier breakdown in Alzheimer disease and other neurodegenerative disorders. Nat Rev Neurol 2018; 14:133-150. [PMID: 29377008 PMCID: PMC5829048 DOI: 10.1038/nrneurol.2017.188] [Citation(s) in RCA: 1693] [Impact Index Per Article: 282.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The blood-brain barrier (BBB) is a continuous endothelial membrane within brain microvessels that has sealed cell-to-cell contacts and is sheathed by mural vascular cells and perivascular astrocyte end-feet. The BBB protects neurons from factors present in the systemic circulation and maintains the highly regulated CNS internal milieu, which is required for proper synaptic and neuronal functioning. BBB disruption allows influx into the brain of neurotoxic blood-derived debris, cells and microbial pathogens and is associated with inflammatory and immune responses, which can initiate multiple pathways of neurodegeneration. This Review discusses neuroimaging studies in the living human brain and post-mortem tissue as well as biomarker studies demonstrating BBB breakdown in Alzheimer disease, Parkinson disease, Huntington disease, amyotrophic lateral sclerosis, multiple sclerosis, HIV-1-associated dementia and chronic traumatic encephalopathy. The pathogenic mechanisms by which BBB breakdown leads to neuronal injury, synaptic dysfunction, loss of neuronal connectivity and neurodegeneration are described. The importance of a healthy BBB for therapeutic drug delivery and the adverse effects of disease-initiated, pathological BBB breakdown in relation to brain delivery of neuropharmaceuticals are briefly discussed. Finally, future directions, gaps in the field and opportunities to control the course of neurological diseases by targeting the BBB are presented.
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Affiliation(s)
- Melanie D Sweeney
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo Street, Los Angeles, California 90089, USA
| | - Abhay P Sagare
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo Street, Los Angeles, California 90089, USA
| | - Berislav V Zlokovic
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo Street, Los Angeles, California 90089, USA
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65
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Sil S, Periyasamy P, Thangaraj A, Chivero ET, Buch S. PDGF/PDGFR axis in the neural systems. Mol Aspects Med 2018; 62:63-74. [PMID: 29409855 DOI: 10.1016/j.mam.2018.01.006] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 12/08/2017] [Accepted: 01/22/2018] [Indexed: 12/14/2022]
Abstract
Platelet-derived growth factors (PDGFs) and their receptors (PDGFRs) are expressed in several cell types including the brain cells such as neuronal progenitors, neurons, astrocytes, and oligodendrocytes. Emerging evidence shows that PDGF-mediated signaling regulates diverse functions in the central nervous system (CNS) such as neurogenesis, cell survival, synaptogenesis, modulation of ligand-gated ion channels, and development of specific types of neurons. Interestingly, PDGF/PDFGR signaling can elicit paradoxical roles in the CNS, depending on the cell type and the activation stimuli and is implicated in the pathogenesis of various neurodegenerative diseases. This review summarizes the role of PDGFs/PDGFRs in several neurodegenerative diseases such as Alzheimer disease, Parkinson disease, amyotrophic lateral sclerosis, brain cancer, cerebral ischemia, HIV-1 and drug abuse. Understanding PDGF/PDGFR signaling may lead to novel approaches for the future development of therapeutic strategies for combating CNS pathologies.
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Affiliation(s)
- Susmita Sil
- Department of Pharmacology and Experimental Neuroscience, 985880 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Palsamy Periyasamy
- Department of Pharmacology and Experimental Neuroscience, 985880 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Annadurai Thangaraj
- Department of Pharmacology and Experimental Neuroscience, 985880 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Ernest T Chivero
- Department of Pharmacology and Experimental Neuroscience, 985880 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Shilpa Buch
- Department of Pharmacology and Experimental Neuroscience, 985880 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE 68198, USA.
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66
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Maksimovich IV. Differences in Cerebral Angioarchitectonics in Alzheimer's Disease in Comparison with Other Neurodegenerative and Ischemic Lesions. ACTA ACUST UNITED AC 2018. [DOI: 10.4236/wjns.2018.84036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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67
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Miners JS, Schulz I, Love S. Differing associations between Aβ accumulation, hypoperfusion, blood-brain barrier dysfunction and loss of PDGFRB pericyte marker in the precuneus and parietal white matter in Alzheimer's disease. J Cereb Blood Flow Metab 2018; 38:103-115. [PMID: 28151041 PMCID: PMC5757436 DOI: 10.1177/0271678x17690761] [Citation(s) in RCA: 149] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Recent studies implicate loss of pericytes in hypoperfusion and blood-brain barrier (BBB) leakage in Alzheimer's disease (AD). In this study, we have measured levels of the pericyte marker, platelet-derived growth factor receptor-β (PDGFRB), and fibrinogen (to assess blood-brain barrier leakage), and analyzed their relationship to indicators of microvessel density (von Willebrand factor level), ante-mortem oxygenation (myelin-associated glycoprotein:proteolipid protein-1 ratio and vascular endothelial growth factor level), Aβ level and plaque load, in precuneus and underlying white matter from 49 AD to 37 control brains. There was reduction in PDGFRB and increased fibrinogen in the precuneus in AD. These changes correlated with reduction in oxygenation and with plaque load. In the underlying white matter, increased fibrinogen correlated with reduced oxygenation, but PDGFRB level was unchanged. The level of platelet-derived growth factor-ββ (PDGF-BB), important for pericyte maintenance, was increased in AD but mainly in the insoluble tissue fraction, correlating with insoluble Aβ level. Loss of the PDGFRB within the precuneus in AD is associated with fibrinogen leakage and reduced oxygenation, and related to fibrillar Aβ accumulation. In contrast, fibrinogen leakage and reduced oxygenation of underlying white matter occur independently of loss of PDGFRB, perhaps secondary to reduced transcortical perfusion.
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Affiliation(s)
| | | | - Seth Love
- Seth Love, School of Clinical Sciences,
University of Bristol, Learning & Research level 2, Southmead Hospital,
Bristol BS10 5NB, UK.
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68
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Mann AP, Scodeller P, Hussain S, Braun GB, Mölder T, Toome K, Ambasudhan R, Teesalu T, Lipton SA, Ruoslahti E. Identification of a peptide recognizing cerebrovascular changes in mouse models of Alzheimer's disease. Nat Commun 2017; 8:1403. [PMID: 29123083 PMCID: PMC5680235 DOI: 10.1038/s41467-017-01096-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 08/17/2017] [Indexed: 01/02/2023] Open
Abstract
Cerebrovascular changes occur in Alzheimer’s disease (AD). Using in vivo phage display, we searched for molecular markers of the neurovascular unit, including endothelial cells and astrocytes, in mouse models of AD. We identified a cyclic peptide, CDAGRKQKC (DAG), that accumulates in the hippocampus of hAPP-J20 mice at different ages. Intravenously injected DAG peptide homes to neurovascular unit endothelial cells and to reactive astrocytes in mouse models of AD. We identified connective tissue growth factor (CTGF), a matricellular protein that is highly expressed in the brain of individuals with AD and in mouse models, as the target of the DAG peptide. We also showed that exogenously delivered DAG homes to the brain in mouse models of glioblastoma, traumatic brain injury, and Parkinson’s disease. DAG may potentially be used as a tool to enhance delivery of therapeutics and imaging agents to sites of vascular changes and astrogliosis in diseases associated with neuroinflammation. Cerebrovascular changes and astrogliosis occur in Alzheimer’s disease (AD). Using an in vivo phage display technique, the authors identified a peptide that upon systematic administration, can home to brain endothelial cells and astrocytes in mouse models of AD at the early stages of the disease.
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Affiliation(s)
- Aman P Mann
- Cancer Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Pablo Scodeller
- Cancer Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA.,Laboratory of Cancer Biology, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, 50411, Estonia
| | - Sazid Hussain
- Cancer Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA.,AivoCode Inc., La Jolla, CA, 92037, USA
| | - Gary B Braun
- Cancer Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Tarmo Mölder
- Laboratory of Cancer Biology, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, 50411, Estonia
| | - Kadri Toome
- Laboratory of Cancer Biology, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, 50411, Estonia
| | - Rajesh Ambasudhan
- Neurodegenerative Disease Center, Scintillon Institute, San Diego, CA, 92121, USA
| | - Tambet Teesalu
- Laboratory of Cancer Biology, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, 50411, Estonia
| | - Stuart A Lipton
- Neurodegenerative Disease Center, Scintillon Institute, San Diego, CA, 92121, USA.,Department of Neurosciences, University of California, San Diego, School of Medicine, La Jolla, CA, 92093, USA
| | - Erkki Ruoslahti
- Cancer Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA. .,Center for Nanomedicine and Department of Cell, Molecular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA.
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69
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Montagne A, Zhao Z, Zlokovic BV. Alzheimer's disease: A matter of blood-brain barrier dysfunction? J Exp Med 2017; 214:3151-3169. [PMID: 29061693 PMCID: PMC5679168 DOI: 10.1084/jem.20171406] [Citation(s) in RCA: 446] [Impact Index Per Article: 63.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Revised: 09/22/2017] [Accepted: 09/26/2017] [Indexed: 12/22/2022] Open
Abstract
Montagne et al. examine the role of blood–brain barrier (BBB) dysfunction in Alzheimer’s neurodegeneration and how targeting the BBB can influence the course of neurological disorder in transgenic models with human APP, PSEN1 and TAU mutations, APOE4 (major genetic risk), and pericyte degeneration causing loss of BBB integrity. The blood–brain barrier (BBB) keeps neurotoxic plasma-derived components, cells, and pathogens out of the brain. An early BBB breakdown and/or dysfunction have been shown in Alzheimer’s disease (AD) before dementia, neurodegeneration and/or brain atrophy occur. However, the role of BBB breakdown in neurodegenerative disorders is still not fully understood. Here, we examine BBB breakdown in animal models frequently used to study the pathophysiology of AD, including transgenic mice expressing human amyloid-β precursor protein, presenilin 1, and tau mutations, and apolipoprotein E, the strongest genetic risk factor for AD. We discuss the role of BBB breakdown and dysfunction in neurodegenerative process, pitfalls in BBB measurements, and how targeting the BBB can influence the course of neurological disorder. Finally, we comment on future approaches and models to better define, at the cellular and molecular level, the underlying mechanisms between BBB breakdown and neurodegeneration as a basis for developing new therapies for BBB repair to control neurodegeneration.
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Affiliation(s)
- Axel Montagne
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, Los Angeles, CA.,Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, Los Angeles, CA
| | - Zhen Zhao
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, Los Angeles, CA.,Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, Los Angeles, CA
| | - Berislav V Zlokovic
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, Los Angeles, CA.,Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, Los Angeles, CA
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70
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Disturbances in the control of capillary flow in an aged APP swe/PS1ΔE9 model of Alzheimer's disease. Neurobiol Aging 2017; 62:82-94. [PMID: 29131981 DOI: 10.1016/j.neurobiolaging.2017.10.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 10/04/2017] [Accepted: 10/06/2017] [Indexed: 02/08/2023]
Abstract
Vascular changes are thought to contribute to the development of Alzheimer's disease, and both cerebral blood flow and its responses during neural activation are reduced before Alzheimer's disease symptoms onset. One hypothetical explanation is that capillary dysfunction reduces oxygen extraction efficacy. This study compares the morphology and hemodynamics of the microvasculature in the somatosensory cortex of 18-month-old APPSWE/PS1ΔE9 (transgenic [Tg]) mice and wild-type (WT) littermates. In particular, the extent to which their capillary transit times homogenize during functional activation was measured and compared. Capillary length density was similar in both groups but capillary blood flow during rest was lower in the Tg mice, indicating that cortical oxygen availability is reduced. The capillary hemodynamic response to functional activation was larger, and lasted longer in Tg mice than in WT mice. The homogenization of capillary transit times during functional activation, which we previously demonstrated in young mice, was absent in the Tg mice. This study demonstrates that both neurovascular coupling and capillary function are profoundly disturbed in aged Tg and WT mice.
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71
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Sweeney MD, Ayyadurai S, Zlokovic BV. Pericytes of the neurovascular unit: key functions and signaling pathways. Nat Neurosci 2017; 19:771-83. [PMID: 27227366 DOI: 10.1038/nn.4288] [Citation(s) in RCA: 706] [Impact Index Per Article: 100.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 02/29/2016] [Indexed: 12/12/2022]
Abstract
Pericytes are vascular mural cells embedded in the basement membrane of blood microvessels. They extend their processes along capillaries, pre-capillary arterioles and post-capillary venules. CNS pericytes are uniquely positioned in the neurovascular unit between endothelial cells, astrocytes and neurons. They integrate, coordinate and process signals from their neighboring cells to generate diverse functional responses that are critical for CNS functions in health and disease, including regulation of the blood-brain barrier permeability, angiogenesis, clearance of toxic metabolites, capillary hemodynamic responses, neuroinflammation and stem cell activity. Here we examine the key signaling pathways between pericytes and their neighboring endothelial cells, astrocytes and neurons that control neurovascular functions. We also review the role of pericytes in CNS disorders including rare monogenic diseases and complex neurological disorders such as Alzheimer's disease and brain tumors. Finally, we discuss directions for future studies.
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Affiliation(s)
- Melanie D Sweeney
- Department of Physiology and Biophysics, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA.,Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Shiva Ayyadurai
- Systems Biology Group, CytoSolve Research Division, Cambridge, Massachusetts, USA
| | - Berislav V Zlokovic
- Department of Physiology and Biophysics, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA.,Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
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72
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Kisler K, Nelson AR, Montagne A, Zlokovic BV. Cerebral blood flow regulation and neurovascular dysfunction in Alzheimer disease. Nat Rev Neurosci 2017; 18:419-434. [PMID: 28515434 PMCID: PMC5759779 DOI: 10.1038/nrn.2017.48] [Citation(s) in RCA: 763] [Impact Index Per Article: 109.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cerebral blood flow (CBF) regulation is essential for normal brain function. The mammalian brain has evolved a unique mechanism for CBF control known as neurovascular coupling. This mechanism ensures a rapid increase in the rate of CBF and oxygen delivery to activated brain structures. The neurovascular unit is composed of astrocytes, mural vascular smooth muscle cells and pericytes, and endothelia, and regulates neurovascular coupling. This Review article examines the cellular and molecular mechanisms within the neurovascular unit that contribute to CBF control, and neurovascular dysfunction in neurodegenerative disorders such as Alzheimer disease.
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Affiliation(s)
- Kassandra Kisler
- Zilkha Neurogenetic Institute, 1501 San Pablo Street, Los Angeles, California 90089, USA
| | - Amy R Nelson
- Zilkha Neurogenetic Institute, 1501 San Pablo Street, Los Angeles, California 90089, USA
| | - Axel Montagne
- Zilkha Neurogenetic Institute, 1501 San Pablo Street, Los Angeles, California 90089, USA
| | - Berislav V Zlokovic
- Zilkha Neurogenetic Institute, 1501 San Pablo Street, Los Angeles, California 90089, USA
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73
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Vascular protective effects of KLF2 on Aβ-induced toxicity: Implications for Alzheimer’s disease. Brain Res 2017; 1663:174-183. [DOI: 10.1016/j.brainres.2017.01.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Revised: 12/29/2016] [Accepted: 01/02/2017] [Indexed: 11/19/2022]
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74
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Mamelak M. Energy and the Alzheimer brain. Neurosci Biobehav Rev 2017; 75:297-313. [PMID: 28193453 DOI: 10.1016/j.neubiorev.2017.02.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 01/30/2017] [Accepted: 02/01/2017] [Indexed: 01/01/2023]
Abstract
The high energy demands of the poorly myelinated long axon hippocampal and cortical neurons render these neurons selectively vulnerable to degeneration in Alzheimer's disease. However, pathology engages all of the major elements of the neurovascular unit of the mature Alzheimer brain, the neurons, glia and blood vessels. Neurons present with retrograde degeneration of the axodendritic tree, capillaries with string vessels and markedly reduced densities and glia with signs of inflammatory activation. The neurons, capillaries and astrocytes of the mature Alzheimer brain harbor structurally defective mitochondria. Clinically, reduced glucose utilization, decades before cognitive deterioration, betrays ongoing energy insufficiency. β-hydroxybutyrate and γ-hydroxybutyrate can both provide energy to the brain when glucose utilization is blocked. Early work in mouse models of Alzheimer's disease demonstrate their ability to reverse the pathological changes in the Alzheimer brain and initial clinical trials reveal their ability to improve cognition and every day function. Supplying the brain with energy holds great promise for delaying the onset of Alzheimer's disease and slowing its progress.
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75
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Pericyte degeneration leads to neurovascular uncoupling and limits oxygen supply to brain. Nat Neurosci 2017; 20:406-416. [PMID: 28135240 PMCID: PMC5323291 DOI: 10.1038/nn.4489] [Citation(s) in RCA: 344] [Impact Index Per Article: 49.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Accepted: 12/30/2016] [Indexed: 12/11/2022]
Abstract
Pericytes are perivascular mural cells of brain capillaries that are positioned centrally within the neurovascular unit between endothelial cells, astrocytes and neurons. This unique position allows them to play a major role in regulating key neurovascular functions of the brain. The role of pericytes in the regulation of cerebral blood flow (CBF) and neurovascular coupling remains, however, debatable. Using loss-of-function pericyte-deficient mice, here we show that pericyte degeneration diminishes global and individual capillary CBF responses to neuronal stimulus resulting in neurovascular uncoupling, reduced oxygen supply to brain and metabolic stress. We show that these neurovascular deficits lead over time to impaired neuronal excitability and neurodegenerative changes. Thus, pericyte degeneration as seen in neurological disorders such as Alzheimer’s disease may contribute to neurovascular dysfunction and neurodegeneration associated with human disease.
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76
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Erdő F, Denes L, de Lange E. Age-associated physiological and pathological changes at the blood-brain barrier: A review. J Cereb Blood Flow Metab 2017; 37:4-24. [PMID: 27837191 PMCID: PMC5363756 DOI: 10.1177/0271678x16679420] [Citation(s) in RCA: 299] [Impact Index Per Article: 42.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 10/21/2016] [Accepted: 10/24/2016] [Indexed: 12/13/2022]
Abstract
The age-associated decline of the neurological and cognitive functions becomes more and more serious challenge for the developed countries with the increasing number of aged populations. The morphological and biochemical changes in the aging brain are the subjects of many extended research projects worldwide for a long time. However, the crucial role of the blood-brain barrier (BBB) impairment and disruption in the pathological processes in age-associated neurodegenerative disorders received special attention just for a few years. This article gives an overview on the major elements of the blood-brain barrier and its supporting mechanisms and also on their alterations during development, physiological aging process and age-associated neurodegenerative disorders (Alzheimer's disease, multiple sclerosis, Parkinson's disease, pharmacoresistant epilepsy). Besides the morphological alterations of the cellular elements (endothelial cells, astrocytes, pericytes, microglia, neuronal elements) of the BBB and neurovascular unit, the changes of the barrier at molecular level (tight junction proteins, adheres junction proteins, membrane transporters, basal lamina, extracellular matrix) are also summarized. The recognition of new players and initiators of the process of neurodegeneration at the level of the BBB may offer new avenues for novel therapeutic approaches for the treatment of numerous chronic neurodegenerative disorders currently without effective medication.
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Affiliation(s)
- Franciska Erdő
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - László Denes
- Institute of Pharmacology & Pharmacotherapy, Semmelweis University, Budapest, Hungary
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77
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Nikolakopoulou AM, Zhao Z, Montagne A, Zlokovic BV. Regional early and progressive loss of brain pericytes but not vascular smooth muscle cells in adult mice with disrupted platelet-derived growth factor receptor-β signaling. PLoS One 2017; 12:e0176225. [PMID: 28441414 PMCID: PMC5404855 DOI: 10.1371/journal.pone.0176225] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 03/18/2017] [Indexed: 11/19/2022] Open
Abstract
Pericytes regulate key neurovascular functions of the brain. Studies in pericyte-deficient transgenic mice with aberrant signaling between endothelial-derived platelet-derived growth factor BB (PDGF-BB) and platelet-derived growth factor receptor β (PDGFRβ) in pericytes have contributed to better understanding of the role of pericytes in the brain. Here, we studied PdgfrβF7/F7 mice, which carry seven point mutations that disrupt PDGFRβ signaling causing loss of pericytes and vascular smooth muscle cells (VSMCs) in the developing brain. We asked whether these mice have a stable or progressive vascular phenotype after birth, and whether both pericyte and VSMCs populations are affected in the adult brain. We found an early and progressive region-dependent loss of brain pericytes, microvascular reductions and blood-brain barrier (BBB) breakdown, which were more pronounced in the cortex, hippocampus and striatum than in the thalamus, whereas VSMCs population remained unaffected at the time when pericyte loss was already established. For example, compared to age-matched controls, PdgfrβF7/F7 mice between 4-6 and 36-48 weeks of age developed a region-dependent loss in pericyte coverage (22-46, 24-44 and 4-31%) and cell numbers (36-49, 34-64 and 11-36%), reduction in capillary length (20-39, 13-46 and 1-30%), and an increase in extravascular fibrinogen-derived deposits (3.4-5.2, 2.8-4.1 and 0-3.6-fold) demonstrating BBB breakdown in the cortex, hippocampus and thalamus, respectively. Capillary reductions and BBB breakdown correlated with loss of pericyte coverage. Our data suggest that PdgfrβF7/F7 mice develop an aggressive and rapid vascular phenotype without appreciable early involvement of VSMCs, therefore providing a valuable model to study regional effects of pericyte loss on brain vascular and neuronal functions. This model could be a useful tool for future studies directed at understanding the role of pericytes in the pathogenesis of neurological disorders associated with pericyte loss such as vascular dementia, Alzheimer's disease, amyotrophic lateral sclerosis, stroke and human immunodeficiency virus-associated neurocognitive disorder.
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Affiliation(s)
- Angeliki Maria Nikolakopoulou
- Department of Physiology and Biophysics and Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Zhen Zhao
- Department of Physiology and Biophysics and Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Axel Montagne
- Department of Physiology and Biophysics and Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Berislav V. Zlokovic
- Department of Physiology and Biophysics and Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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78
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He L, Vanlandewijck M, Raschperger E, Andaloussi Mäe M, Jung B, Lebouvier T, Ando K, Hofmann J, Keller A, Betsholtz C. Analysis of the brain mural cell transcriptome. Sci Rep 2016; 6:35108. [PMID: 27725773 PMCID: PMC5057134 DOI: 10.1038/srep35108] [Citation(s) in RCA: 157] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 09/22/2016] [Indexed: 01/20/2023] Open
Abstract
Pericytes, the mural cells of blood microvessels, regulate microvascular development and function and have been implicated in many brain diseases. However, due to a paucity of defining markers, pericyte identification and functional characterization remain ambiguous and data interpretation problematic. In mice carrying two transgenic reporters, Pdgfrb-eGFP and NG2-DsRed, we found that double-positive cells were vascular mural cells, while the single reporters marked additional, but non-overlapping, neuroglial cells. Double-positive cells were isolated by fluorescence-activated cell sorting (FACS) and analyzed by RNA sequencing. To reveal defining patterns of mural cell transcripts, we compared the RNA sequencing data with data from four previously published studies. The meta-analysis provided a conservative catalogue of 260 brain mural cell-enriched gene transcripts. We validated pericyte-specific expression of two novel markers, vitronectin (Vtn) and interferon-induced transmembrane protein 1 (Ifitm1), using fluorescent in situ hybridization and immunohistochemistry. We further analyzed signaling pathways and interaction networks of the pericyte-enriched genes in silico. This work provides novel insight into the molecular composition of brain mural cells. The reported gene catalogue facilitates identification of brain pericytes by providing numerous new candidate marker genes and is a rich source for new hypotheses for future studies of brain mural cell physiology and pathophysiology.
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Affiliation(s)
- Liqun He
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Michael Vanlandewijck
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
- Integrated Cardio Metabolic Centre (ICMC), Karolinska Institute, Novum, SE-141 57 Huddinge, Stockholm, Sweden
| | - Elisabeth Raschperger
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
- Integrated Cardio Metabolic Centre (ICMC), Karolinska Institute, Novum, SE-141 57 Huddinge, Stockholm, Sweden
| | - Maarja Andaloussi Mäe
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Bongnam Jung
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Thibaud Lebouvier
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Koji Ando
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Jennifer Hofmann
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Annika Keller
- Division of Neurosurgery, Zürich University Hospital, Zürich University, Zürich, Switzerland
| | - Christer Betsholtz
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
- Integrated Cardio Metabolic Centre (ICMC), Karolinska Institute, Novum, SE-141 57 Huddinge, Stockholm, Sweden
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79
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Gerson JE, Mudher A, Kayed R. Potential mechanisms and implications for the formation of tau oligomeric strains. Crit Rev Biochem Mol Biol 2016; 51:482-496. [PMID: 27650389 PMCID: PMC5285467 DOI: 10.1080/10409238.2016.1226251] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The culmination of many years of increasing research into the toxicity of tau aggregation in neurodegenerative disease has led to the consensus that soluble, oligomeric forms of tau are likely the most toxic entities in disease. While tauopathies overlap in the presence of tau pathology, each disease has a unique combination of symptoms and pathological features; however, most study into tau has grouped tau oligomers and studied them as a homogenous population. Established evidence from the prion field combined with the most recent tau and amyloidogenic protein research suggests that tau is a prion-like protein, capable of seeding the spread of pathology throughout the brain. Thus, it is likely that tau may also form prion-like strains or diverse conformational structures that may differ by disease and underlie some of the differences in symptoms and pathology in neurodegenerative tauopathies. The development of techniques and new technology for the detection of tau oligomeric strains may, therefore, lead to more efficacious diagnostic and treatment strategies for neurodegenerative disease. [Formula: see text].
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Affiliation(s)
- Julia E. Gerson
- George P. and Cynthia Woods Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, Galveston, TX 77555-1045, USA
- Departments of Neurology, and Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555-1045, USA
| | - Amrit Mudher
- Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Rakez Kayed
- George P. and Cynthia Woods Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, Galveston, TX 77555-1045, USA
- Departments of Neurology, and Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555-1045, USA
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80
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Love S, Miners J. Cerebral Hypoperfusion and the Energy Deficit in Alzheimer's Disease. Brain Pathol 2016; 26:607-17. [PMID: 27327656 PMCID: PMC8028913 DOI: 10.1111/bpa.12401] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 06/21/2016] [Accepted: 05/25/2016] [Indexed: 12/19/2022] Open
Abstract
There is a perfusion deficit in Alzheimer's disease (AD), commencing in the precuneus and spreading to other parts of the cerebral cortex. The deficit anticipates the development of dementia, contributes to brain damage, and is caused by both functional and structural abnormalities of the cerebral vasculature. Most of the abnormalities are probably secondary to the accumulation of Aβ but the consequent hypoperfusion may, in turn, increase Aβ production. In the early stages of disease, abnormalities that cause vasoconstriction predominate. These include cholinergic vascular denervation, inhibition of endothelial nitric oxide synthase, increased production of endothelin-1 production and possibly also of angiotensin II. Patients with AD also have an increased prevalence of structural disease of cerebral microvessels, particularly CAA and capillary damage, and particularly in the later stages of disease these are likely to make an important contribution to the cerebral hypoperfusion. The metabolic abnormalities that cause early vascular dysfunction offer several targets for therapeutic intervention. However, for intervention to be effective it probably needs to be early. Prolonged cerebral hypoperfusion may induce compensatory circulatory changes that are themselves damaging, including hypertension and small vessel disease. This has implications for the use of antihypertensive drugs once there is accumulation of Aβ within the brain.
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Affiliation(s)
- Seth Love
- Dementia Research Group, Institute of Clinical Neurosciences, School of Clinical SciencesUniversity of BristolBristolUnited Kingom
| | - J.Scott Miners
- Dementia Research Group, Institute of Clinical Neurosciences, School of Clinical SciencesUniversity of BristolBristolUnited Kingom
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81
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Love S, Miners JS. Cerebrovascular disease in ageing and Alzheimer's disease. Acta Neuropathol 2016; 131:645-58. [PMID: 26711459 PMCID: PMC4835514 DOI: 10.1007/s00401-015-1522-0] [Citation(s) in RCA: 200] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 12/03/2015] [Accepted: 12/07/2015] [Indexed: 12/14/2022]
Abstract
Cerebrovascular disease (CVD) and Alzheimer’s disease (AD) have more in common than their association with ageing. They share risk factors and overlap neuropathologically. Most patients with AD have Aβ amyloid angiopathy and degenerative changes affecting capillaries, and many have ischaemic parenchymal abnormalities. Structural vascular disease contributes to the ischaemic abnormalities in some patients with AD. However, the stereotyped progression of hypoperfusion in this disease, affecting first the precuneus and cingulate gyrus, then the frontal and temporal cortex and lastly the occipital cortex, suggests that other factors are more important, particularly in early disease. Whilst demand for oxygen and glucose falls in late disease, functional MRI, near infrared spectroscopy to measure the saturation of haemoglobin by oxygen, and biochemical analysis of myelin proteins with differential susceptibility to reduced oxygenation have all shown that the reduction in blood flow in AD is primarily a problem of inadequate blood supply, not reduced metabolic demand. Increasing evidence points to non-structural vascular dysfunction rather than structural abnormalities of vessel walls as the main cause of cerebral hypoperfusion in AD. Several mediators are probably responsible. One that is emerging as a major contributor is the vasoconstrictor endothelin-1 (EDN1). Whilst there is clearly an additive component to the clinical and pathological effects of hypoperfusion and AD, experimental and clinical observations suggest that the disease processes also interact mechanistically at a cellular level in a manner that exacerbates both. The elucidation of some of the mechanisms responsible for hypoperfusion in AD and for the interactions between CVD and AD has led to the identification of several novel therapeutic approaches that have the potential to ameliorate ischaemic damage and slow the progression of neurodegenerative disease.
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Affiliation(s)
- Seth Love
- Institute of Clinical Neurosciences, School of Clinical Sciences, Learning and Research Level 2, Southmead Hospital, University of Bristol, Bristol, BS10 5NB, UK.
| | - J Scott Miners
- Institute of Clinical Neurosciences, School of Clinical Sciences, Learning and Research Level 2, Southmead Hospital, University of Bristol, Bristol, BS10 5NB, UK
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82
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Nelson AR, Sweeney MD, Sagare AP, Zlokovic BV. Neurovascular dysfunction and neurodegeneration in dementia and Alzheimer's disease. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1862:887-900. [PMID: 26705676 PMCID: PMC4821735 DOI: 10.1016/j.bbadis.2015.12.016] [Citation(s) in RCA: 366] [Impact Index Per Article: 45.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 12/10/2015] [Accepted: 12/10/2015] [Indexed: 02/07/2023]
Abstract
Vascular insults can initiate a cascade of molecular events leading to neurodegeneration, cognitive impairment, and dementia. Here, we review the cellular and molecular mechanisms in cerebral blood vessels and the pathophysiological events leading to cerebral blood flow dysregulation and disruption of the neurovascular unit and the blood-brain barrier, which all may contribute to the onset and progression of dementia and Alzheimer's disease (AD). Particularly, we examine the link between neurovascular dysfunction and neurodegeneration including the effects of AD genetic risk factors on cerebrovascular functions and clearance of Alzheimer's amyloid-β peptide toxin, and the impact of vascular risk factors, environment, and lifestyle on cerebral blood vessels, which in turn may affect synaptic, neuronal, and cognitive functions. Finally, we examine potential experimental treatments for dementia and AD based on the neurovascular model, and discuss some critical questions to be addressed by future studies. This article is part of a Special Issue entitled: Vascular Contributions to Cognitive Impairment and Dementia edited by M. Paul Murphy, Roderick A. Corriveau and Donna M. Wilcock.
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Affiliation(s)
- Amy R Nelson
- Department of Physiology and Biophysics and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90089, USA
| | - Melanie D Sweeney
- Department of Physiology and Biophysics and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90089, USA
| | - Abhay P Sagare
- Department of Physiology and Biophysics and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90089, USA
| | - Berislav V Zlokovic
- Department of Physiology and Biophysics and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90089, USA.
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83
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Zhao Z, Nelson AR, Betsholtz C, Zlokovic BV. Establishment and Dysfunction of the Blood-Brain Barrier. Cell 2016; 163:1064-1078. [PMID: 26590417 DOI: 10.1016/j.cell.2015.10.067] [Citation(s) in RCA: 1065] [Impact Index Per Article: 133.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Indexed: 12/11/2022]
Abstract
Structural and functional brain connectivity, synaptic activity, and information processing require highly coordinated signal transduction between different cell types within the neurovascular unit and intact blood-brain barrier (BBB) functions. Here, we examine the mechanisms regulating the formation and maintenance of the BBB and functions of BBB-associated cell types. Furthermore, we discuss the growing evidence associating BBB breakdown with the pathogenesis of inherited monogenic neurological disorders and complex multifactorial diseases, including Alzheimer's disease.
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Affiliation(s)
- Zhen Zhao
- Department of Physiology and Biophysics and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90089, USA
| | - Amy R Nelson
- Department of Physiology and Biophysics and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90089, USA
| | - Christer Betsholtz
- Department of Immunology, Genetics, and Pathology, Rudbeck Laboratory, 75185 Uppsala, Sweden
| | - Berislav V Zlokovic
- Department of Physiology and Biophysics and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90089, USA.
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84
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Accelerated pericyte degeneration and blood-brain barrier breakdown in apolipoprotein E4 carriers with Alzheimer's disease. J Cereb Blood Flow Metab 2016; 36:216-27. [PMID: 25757756 PMCID: PMC4758554 DOI: 10.1038/jcbfm.2015.44] [Citation(s) in RCA: 434] [Impact Index Per Article: 54.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 02/03/2015] [Accepted: 02/05/2015] [Indexed: 12/29/2022]
Abstract
The blood–brain barrier (BBB) limits the entry of neurotoxic blood-derived products and cells into the brain that is required for normal neuronal functioning and information processing. Pericytes maintain the integrity of the BBB and degenerate in Alzheimer’s disease (AD). The BBB is damaged in AD, particularly in individuals carrying apolipoprotein E4 (APOE4) gene, which is a major genetic risk factor for late-onset AD. The mechanisms underlying the BBB breakdown in AD remain, however, elusive. Here, we show accelerated pericyte degeneration in AD APOE4 carriers >AD APOE3 carriers >non-AD controls, which correlates with the magnitude of BBB breakdown to immunoglobulin G and fibrin. We also show accumulation of the proinflammatory cytokine cyclophilin A (CypA) and matrix metalloproteinase-9 (MMP-9) in pericytes and endothelial cells in AD (APOE4 >APOE3), previously shown to lead to BBB breakdown in transgenic APOE4 mice. The levels of the apoE lipoprotein receptor, low-density lipoprotein receptor-related protein-1 (LRP1), were similarly reduced in AD APOE4 and APOE3 carriers. Our data suggest that APOE4 leads to accelerated pericyte loss and enhanced activation of LRP1-dependent CypA–MMP-9 BBB-degrading pathway in pericytes and endothelial cells, which can mediate a greater BBB damage in AD APOE4 compared with AD APOE3 carriers.
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85
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Otellin VA, Khozhai LI, Shishko TT. Reaction of the blood–brain barrier structural elements to normobaric hypoxia in newborn rats. J EVOL BIOCHEM PHYS+ 2015. [DOI: 10.1134/s0022093015050099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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86
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Abstract
Electron microscopy has enlarged the visual horizons of the morphological alterations in Alzheimer's disease (AD). Study of the mitochondria and Golgi apparatus in early cases of AD revealed the principal role that these important organelles play in the drama of pathogenic dialog of AD, substantially affecting energy production and supply, and protein trafficking in neurons and glia. In addition, study of the morphological alterations of the dendritic arbor, dendritic spines and neuronal synapses, which are associated with mitochondrial damage, may reasonably interpret the clinical phenomena of the irreversible decline of the mental faculties and an individual's personality changes. Electron microscopy also reveals the involvement of microvascular alterations in the etiopathogenic background of AD.
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87
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Dalkara T, Alarcon-Martinez L. Cerebral microvascular pericytes and neurogliovascular signaling in health and disease. Brain Res 2015; 1623:3-17. [DOI: 10.1016/j.brainres.2015.03.047] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 03/10/2015] [Accepted: 03/27/2015] [Indexed: 02/07/2023]
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88
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89
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Nikolajsen GN, Kotynski KA, Jensen MS, West MJ. Quantitative analysis of the capillary network of aged APPswe/PS1dE9 transgenic mice. Neurobiol Aging 2015; 36:2954-2962. [PMID: 26364735 DOI: 10.1016/j.neurobiolaging.2015.08.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 08/04/2015] [Accepted: 08/06/2015] [Indexed: 11/26/2022]
Abstract
A combination of immunohistochemical and stereological techniques were used to investigate the capillary network in the cerebral cortex of 18-month-old APPswe/PS1dE9 transgenic (Tg) mice and control littermates. Data regarding total capillary length, segment number, diffusion radius, and pericyte number are presented. The total length was 60 meters and there was a one-to-one relationship between the number of capillary segments and pericytes in both groups. Significant differences were not observed in the Tg and wild-type controls indicating that the Alzheimer's-like amyloidosis produced in this Tg mouse has a minimal affect on the structural integrity of the cerebral capillary network.
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Affiliation(s)
| | | | | | - Mark J West
- Department of Biomedicine, Aarhus University, Aarhus C, Denmark
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90
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Baloyannis SJ, Mavroudis I, Mitilineos D, Baloyannis IS, Costa VG. The hypothalamus in Alzheimer's disease: a Golgi and electron microscope study. Am J Alzheimers Dis Other Demen 2015; 30:478-87. [PMID: 25380804 PMCID: PMC10852817 DOI: 10.1177/1533317514556876] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder, characterized by irreversible decline of mental faculties, emotional and behavioral changes, loss of motor skills, and dysfunction of autonomic nervous system and disruption of circadian rhythms (CRs). We attempted to describe the morphological findings of the hypothalamus in early cases of AD, focusing our study mostly on the suprachiasmatic nucleus (SCN), the supraoptic nucleus (SON), and the paraventricular nucleus (PVN). Samples were processed for electron microscopy and silver impregnation techniques. The hypothalamic nuclei demonstrated a substantial decrease in the neuronal population, which was particularly prominent in the SCN. Marked abbreviation of dendritic arborization, in association with spinal pathology, was also seen. The SON and PVN demonstrated a substantial number of dystrophic axons and abnormal spines. Alzheimer's pathology, such as deposits of amyloid-β peptide and neurofibrillary degeneration, was minimal. Electron microscopy revealed mitochondrial alterations in the cell body and the dendritic branches. The morphological alterations of the hypothalamic nuclei in early cases of AD may be related to the gradual alteration of CRs and the instability of autonomic regulation.
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Affiliation(s)
- Stavros J Baloyannis
- Department of Neurology, Laboratory of Neuropathology and Electron Microscopy, Aristotelian University, Thessaloniki, Greece Laboratory of Neuropathology, Institute for Research on Alzheimer's Disease, Iraklion, Greece
| | - Ioannis Mavroudis
- Department of Neurology, Laboratory of Neuropathology and Electron Microscopy, Aristotelian University, Thessaloniki, Greece
| | - Demetrios Mitilineos
- Department of Neurology, Laboratory of Neuropathology and Electron Microscopy, Aristotelian University, Thessaloniki, Greece
| | - Ioannis S Baloyannis
- Department of Neurology, Laboratory of Neuropathology and Electron Microscopy, Aristotelian University, Thessaloniki, Greece
| | - Vassiliki G Costa
- Department of Neurology, Laboratory of Neuropathology and Electron Microscopy, Aristotelian University, Thessaloniki, Greece Laboratory of Neuropathology, Institute for Research on Alzheimer's Disease, Iraklion, Greece
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91
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Winkler EA, Sagare AP, Zlokovic BV. The pericyte: a forgotten cell type with important implications for Alzheimer's disease? Brain Pathol 2015; 24:371-86. [PMID: 24946075 DOI: 10.1111/bpa.12152] [Citation(s) in RCA: 192] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 05/13/2014] [Indexed: 12/13/2022] Open
Abstract
Pericytes are cells in the blood-brain barrier (BBB) that degenerate in Alzheimer's disease (AD), a neurodegenerative disorder characterized by early neurovascular dysfunction, elevation of amyloid β-peptide (Aβ), tau pathology and neuronal loss, leading to progressive cognitive decline and dementia. Pericytes are uniquely positioned within the neurovascular unit between endothelial cells of brain capillaries, astrocytes and neurons. Recent studies have shown that pericytes regulate key neurovascular functions including BBB formation and maintenance, vascular stability and angioarchitecture, regulation of capillary blood flow, and clearance of toxic cellular by-products necessary for normal functioning of the central nervous system (CNS). Here, we review the concept of the neurovascular unit and neurovascular functions of CNS pericytes. Next, we discuss vascular contributions to AD and review new roles of pericytes in the pathogenesis of AD such as vascular-mediated Aβ-independent neurodegeneration, regulation of Aβ clearance and contributions to tau pathology, neuronal loss and cognitive decline. We conclude that future studies should focus on molecular mechanisms and pathways underlying aberrant signal transduction between pericytes and its neighboring cells within the neurovascular unit, that is, endothelial cells, astrocytes and neurons, which could represent potential therapeutic targets to control pericyte degeneration in AD and the resulting secondary vascular and neuronal degeneration.
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Affiliation(s)
- Ethan A Winkler
- Zilkha Neurogenetic Institute, University of Southern California Keck School of Medicine, Los Angeles, CA; Department of Neurosurgery, University of California San Francisco, San Francisco, CA
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Sweeney MD, Sagare AP, Zlokovic BV. Cerebrospinal fluid biomarkers of neurovascular dysfunction in mild dementia and Alzheimer's disease. J Cereb Blood Flow Metab 2015; 35:1055-68. [PMID: 25899298 PMCID: PMC4640280 DOI: 10.1038/jcbfm.2015.76] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 02/27/2015] [Accepted: 03/08/2015] [Indexed: 02/06/2023]
Abstract
Alzheimer's disease (AD) is the most common form of age-related dementias. In addition to genetics, environment, and lifestyle, growing evidence supports vascular contributions to dementias including dementia because of AD. Alzheimer's disease affects multiple cell types within the neurovascular unit (NVU), including brain vascular cells (endothelial cells, pericytes, and vascular smooth muscle cells), glial cells (astrocytes and microglia), and neurons. Thus, identifying and integrating biomarkers of the NVU cell-specific responses and injury with established AD biomarkers, amyloid-β (Aβ) and tau, has a potential to contribute to better understanding of the disease process in dementias including AD. Here, we discuss the existing literature on cerebrospinal fluid biomarkers of the NVU cell-specific responses during early stages of dementia and AD. We suggest that the clinical usefulness of established AD biomarkers, Aβ and tau, could be further improved by developing an algorithm that will incorporate biomarkers of the NVU cell-specific responses and injury. Such biomarker algorithm could aid in early detection and intervention as well as identify novel treatment targets to delay disease onset, slow progression, and/or prevent AD.
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Affiliation(s)
- Melanie D Sweeney
- Department of Physiology and Biophysics, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Abhay P Sagare
- Department of Physiology and Biophysics, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Berislav V Zlokovic
- Department of Physiology and Biophysics, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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93
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Baloyannis SJ. Staining neurons with Golgi techniques in degenerative diseases of the brain. Neural Regen Res 2015; 10:693-5. [PMID: 26109934 PMCID: PMC4468751 DOI: 10.4103/1673-5374.156950] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2015] [Indexed: 11/04/2022] Open
Affiliation(s)
- Stavros J Baloyannis
- Department of Neurology, Aristotelian University, Angelaki 5, Thessaloniki 546 21, Greece
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94
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Glio-vascular changes during ageing in wild-type and Alzheimer's disease-like APP/PS1 mice. Brain Res 2015; 1620:153-68. [PMID: 25966615 DOI: 10.1016/j.brainres.2015.04.056] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 03/30/2015] [Accepted: 04/29/2015] [Indexed: 12/14/2022]
Abstract
Vascular and glial involvement in the development of neurodegenerative disorders, such as Alzheimer's disease (AD), and age-related brain vulnerabilities have been suggested. Therefore, we sought to: (i) investigate which vascular and glial events are evident in ageing and/or AD, (ii) to establish the temporal evolution of vascular and glial changes in AD-like and wild-type (WT) mice and (iii) to relate them to amyloid-β (Aβ) peptide accumulation. We examined immunohistochemically hippocampi and cortex from APP/PS1dE9 and WT C57BL/6 mice along ageing and disease progression (young-adulthood, middle- and old-age). Ageing resulted in the increase in receptor for advanced glycation endproducts expression, as well as the entrance of thrombin and albumin in hippocampal parenchyma. In contrast, the loss of platelet-derived growth factor receptor-β (PDGFR-β) positive cells, in both regions, was only related to AD pathogenesis. Hypovascularization was affected by both ageing and AD in the hippocampus, but resulted from the interaction between both factors in the cortex. Astrogliosis was a result of AD in hippocampus and of both factors in cortex, while microgliosis was associated with fibrillar amyloid plaques in AD-like mice and with the interaction between both factors in each of the studied regions. In sum, these data show that senile plaques precede vascular and glial alterations only in hippocampus, whereas in cortex, vascular and glial alterations, namely the loss of PDGFR-β-positive cells and astrogliosis, accompanied the first senile plaques. Hence, this study points to vascular and glial events that co-exist in AD pathogenesis and age-related brain vulnerabilities.
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95
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Montagne A, Barnes SR, Sweeney MD, Halliday MR, Sagare AP, Zhao Z, Toga AW, Jacobs RE, Liu CY, Amezcua L, Harrington MG, Chui HC, Law M, Zlokovic BV. Blood-brain barrier breakdown in the aging human hippocampus. Neuron 2015; 85:296-302. [PMID: 25611508 DOI: 10.1016/j.neuron.2014.12.032] [Citation(s) in RCA: 1353] [Impact Index Per Article: 150.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/10/2014] [Indexed: 11/27/2022]
Abstract
UNLABELLED The blood-brain barrier (BBB) limits entry of blood-derived products, pathogens, and cells into the brain that is essential for normal neuronal functioning and information processing. Post-mortem tissue analysis indicates BBB damage in Alzheimer's disease (AD). The timing of BBB breakdown remains, however, elusive. Using an advanced dynamic contrast-enhanced MRI protocol with high spatial and temporal resolutions to quantify regional BBB permeability in the living human brain, we show an age-dependent BBB breakdown in the hippocampus, a region critical for learning and memory that is affected early in AD. The BBB breakdown in the hippocampus and its CA1 and dentate gyrus subdivisions worsened with mild cognitive impairment that correlated with injury to BBB-associated pericytes, as shown by the cerebrospinal fluid analysis. Our data suggest that BBB breakdown is an early event in the aging human brain that begins in the hippocampus and may contribute to cognitive impairment. VIDEO ABSTRACT
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Affiliation(s)
- Axel Montagne
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Samuel R Barnes
- Biological Imaging Center, Beckman Institute, California Institute of Technology, Pasadena, CA 91101, USA
| | - Melanie D Sweeney
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Matthew R Halliday
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Abhay P Sagare
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Zhen Zhao
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Arthur W Toga
- Institute for Neuroimaging & Informatics, Department of Neurology, University of Southern California, Los Angeles, CA 90089, USA
| | - Russell E Jacobs
- Biological Imaging Center, Beckman Institute, California Institute of Technology, Pasadena, CA 91101, USA
| | - Collin Y Liu
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA; Department of Radiology, Neuroradiology Division, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Lilyana Amezcua
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | | | - Helena C Chui
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Meng Law
- Department of Radiology, Neuroradiology Division, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Berislav V Zlokovic
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA.
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96
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Maksimovich IV. Dementia and Cognitive Impairment Reduction after Laser Transcatheter Treatment of Alzheimer’s Disease. ACTA ACUST UNITED AC 2015. [DOI: 10.4236/wjns.2015.53021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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97
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Abstract
Golgi silver impregnation techniques remain ideal methods for the visualization of the neurons as a whole in formalin fixed brains and paraffin sections, enabling to obtain insight into the morphological and morphometric characters of the dendritic arbor, and the estimation of the morphology of the spines and the spinal density, since they delineate the profile of nerve cells with unique clarity and precision. In addition, the Golgi technique enables the study of the topographic relationships between neurons and neuronal circuits in normal conditions, and the following of the spatiotemporal morphological alterations occurring during degenerative processes. The Golgi technique has undergone many modifications in order to be enhanced and to obtain the optimal and maximal visualization of neurons and neuronal processes, the minimal precipitations, the abbreviation of the time required for the procedure, enabling the accurate study and description of specific structures of the brain. In the visualization of the sequential stages of the neuronal degeneration and death, the Golgi method plays a prominent role in the visualization of degenerating axons and dendrites, synaptic “boutons,” and axonal terminals and organelles of the cell body. In addition, new versions of the techniques increases the capacity of precise observation of the neurofibrillary degeneration, the proliferation of astrocytes, the activation of the microglia, and the morphology of capillaries in autopsy material of debilitating diseases of the central nervous system.
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98
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Effect and mechanism of salvianolic acid B on the myocardial ischemia-reperfusion injury in rats. ASIAN PAC J TROP MED 2014; 7:280-4. [PMID: 24507676 DOI: 10.1016/s1995-7645(14)60038-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 01/15/2014] [Accepted: 03/15/2014] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE To investigate the effect of salvianolic acid B on rats with myocardial ischemia-reperfusion injury. METHODS SD rats were randomly divided into five groups (n=10 in each group): A sham operation group, B ischemic reperfusion group model group, C low dose salvianolic acid B group, D median dose salvianolic acid B group, E high dose salvianolic acid B group. One hour after establishment of the myocardial ischemia-reperfusion model, the concentration and the apoptotic index of the plasma level of myocardial enzymes (CTn I, CK-MB), SOD, MDA, NO, ET were measured. Heart tissues were obtained and micro-structural changes were observed. RESULTS Compared the model group, the plasma CTn, CK-MB, MDA and ET contents were significantly increased, NO, T-SOD contents were decreased in the treatment group (group C, D, and E) (P<0.05); compared with group E, the plasma CTn I, CK-MB, MDA and ET levels were increased, the NO, T-SOD levels were decreased in groups C and D (P<0.05). Infarct size was significantly reduced, and the myocardial ultrastructural changes were improved significantly in treatment group. CONCLUSIONS Salvianolic acid B has a significant protective effect on myocardial ischemia-reperfusion injury. It can alleviate oxidative stress, reduce calcium overload, improve endothelial function and so on.
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99
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Involvement of matrix metalloproteinase-9 in amyloid-β 1-42-induced shedding of the pericyte proteoglycan NG2. J Neuropathol Exp Neurol 2014; 73:684-92. [PMID: 24918635 PMCID: PMC4072439 DOI: 10.1097/nen.0000000000000084] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Supplemental digital content is available in the text. Deposition of amyloid-β (Aβ) 1–42, the major component of senile plaques characteristic of Alzheimer disease, affects brain microvascular integrity and causes blood-brain barrier dysfunction, increased angiogenesis, and pericyte degeneration. To understand the cellular events underlying Aβ1–42 effects on microvascular alterations, we investigated whether different aggregation forms of Aβ1–42 affect shedding of the pericyte proteoglycan NG2 and whether they affect proteolytic cleavage mediated by matrix metalloproteinase (MMP)-9. We found decreased levels of soluble NG2, total MMP-9, and MMP-9 activity in pericyte culture supernatants in response to fibril-enriched preparations of Aβ1–42. Conversely, oligomer-enriched preparations of Aβ1–42 increased soluble NG2 levels in the supernatants. This increase was ablated by the MMP-9/MMP-2 inhibitor SB-3CT. There was also a trend toward increased MMP-9 activity observed after oligomeric Aβ1–42 exposure. Our results, demonstrating an Aβ1–42 aggregation-dependent effect on levels of NG2 and MMP-9, support previous studies showing an impact of Aβ1–42 on vascular integrity and thereby add to our understanding of mechanisms behind the microvascular changes commonly found in patients with Alzheimer disease.
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100
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Hurtado-Alvarado G, Cabañas-Morales AM, Gómez-Gónzalez B. Pericytes: brain-immune interface modulators. Front Integr Neurosci 2014; 7:80. [PMID: 24454281 PMCID: PMC3887314 DOI: 10.3389/fnint.2013.00080] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 12/26/2013] [Indexed: 01/08/2023] Open
Abstract
The premise that the central nervous system is immune-privileged arose from the fact that direct contact between immune and nervous cells is hindered by the blood-brain barrier. However, the blood-brain barrier also comprises the interface between the immune and nervous systems by secreting chemo-attractant molecules and by modulating immune cell entry into the brain. The majority of published studies on the blood-brain barrier focus on endothelial cells (ECs), which are a critical component, but not the only one; other cellular components include astroglia, microglia, and pericytes. Pericytes are poorly studied in comparison with astrocytes or ECs; they are mesenchymal cells that can modify their ultrastructure and gene expression in response to changes in the central nervous system microenvironment. Pericytes have a unique synergistic relationship with brain ECs in the regulation of capillary permeability through secretion of cytokines, chemokines, nitric oxide, matrix metalloproteinases, and by means of capillary contraction. Those pericyte manifestations are related to changes in blood-brain barrier permeability by an increase in endocytosis-mediated transport and by tight junction disruption. In addition, recent reports demonstrate that pericytes control the migration of leukocytes in response to inflammatory mediators by up-regulating the expression of adhesion molecules and releasing chemo-attractants; however, under physiological conditions they appear to be immune-suppressors. Better understanding of the immune properties of pericytes and their participation in the effects of brain infections, neurodegenerative diseases, and sleep loss will be achieved by analyzing pericyte ultrastructure, capillary coverage, and protein expression. That knowledge may provide a mechanism by which pericytes participate in the maintenance of the proper function of the brain-immune interface.
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Affiliation(s)
| | | | - Beatriz Gómez-Gónzalez
- Area of Neurosciences, Department of Biology of Reproduction, Unidad Iztapalapa, Universidad Autónoma MetropolitanaMexico City, Mexico
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