1
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Jimenez AR, Naz N, Miyan JA. Altered folate binding protein expression and folate delivery are associated with congenital hydrocephalus in the hydrocephalic Texas rat. J Cereb Blood Flow Metab 2019; 39:2061-2073. [PMID: 29798726 PMCID: PMC6775583 DOI: 10.1177/0271678x18776226] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Hydrocephalus (HC) is an imbalance in cerebrospinal fluid (CSF) secretion/absorption resulting in fluid accumulation within the brain with consequential pathophysiology. Our research has identified a unique cerebral folate system in which depletion of CSF 10-formyl-tetrahydrofolate-dehydrogenase (FDH) is associated with cortical progenitor cell-cycle arrest in hydrocephalic Texas (H-Tx) rats. We used tissue culture, immunohistochemistry, in-situ PCR and RT-PCR and found that the in-vitro proliferation of arachnoid cells is highly folate-dependent with exacerbated proliferation occurring in hydrocephalic CSF that has low FDH but high folate-receptor-alpha (FRα) and folate. Adding FDH to this CSF prevented aberrant proliferation indicating a regulatory function of FDH on CSF folate concentration. Arachnoid cells have no detectable mRNA for FRα or FDH, but FDH mRNA is found in the choroid plexus (CP) and CSF microvesicles. Co-localization of FDH, FRα and folate suggests important functions of FDH in cerebral folate transport, buffering and function. In conclusion, abnormal CSF levels of FDH, FRα and folate inhibit cortical cell proliferation but allow uncontrolled arachnoid cell division that should increase fluid absorption by increasing the arachnoid although this fails in the hydrocephalic brain. FDH appears to buffer available folate to control arachnoid proliferation and function.
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Affiliation(s)
- Alicia Requena Jimenez
- Faculty of Biology, Medicine & Health, Division of Neuroscience & Experimental Psychology, The University of Manchester, Manchester, UK
| | - Naila Naz
- Faculty of Biology, Medicine & Health, Division of Neuroscience & Experimental Psychology, The University of Manchester, Manchester, UK
| | - Jaleel A Miyan
- Faculty of Biology, Medicine & Health, Division of Neuroscience & Experimental Psychology, The University of Manchester, Manchester, UK
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2
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Kanda H, Shimamura R, Koizumi-Kitajima M, Okano H. Degradation of Extracellular Matrix by Matrix Metalloproteinase 2 Is Essential for the Establishment of the Blood-Brain Barrier in Drosophila. iScience 2019; 16:218-229. [PMID: 31195239 PMCID: PMC6562144 DOI: 10.1016/j.isci.2019.05.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 03/27/2019] [Accepted: 05/21/2019] [Indexed: 12/20/2022] Open
Abstract
The blood-brain barrier (BBB) is an essential system that isolates the central nervous system from the internal environment. Increasing evidence has begun to reveal the molecules that are required for BBB integrity. However, how these components are regulated remains unclear. Here we report that a matrix metalloproteinase, Mmp2, is essential for the establishment of the BBB in Drosophila. In the absence of mmp2, the BBB becomes leaky, which allows the tracer to penetrate the brain. Moreover, the expression pattern of a junctional component, Neuroglian, is altered. We also find that the regulation of the amounts of particular extracellular matrix components is critical for BBB establishment. Furthermore, the process of mesenchymal-epithelial transition of BBB-forming cells is perturbed in the absence of Mmp2. These data indicate that the presence of Mmp(s), which is typically considered to be a risk factor for BBB degradation, is essential for BBB integrity in Drosophila.
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Affiliation(s)
- Hiroshi Kanda
- Department of Physiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
| | - Rieko Shimamura
- Department of Physiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Michiko Koizumi-Kitajima
- Department of Physiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
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3
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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: 1157] [Impact Index Per Article: 231.4] [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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4
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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: 1649] [Impact Index Per Article: 274.8] [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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5
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Nakazato R, Kawabe K, Yamada D, Ikeno S, Mieda M, Shimba S, Hinoi E, Yoneda Y, Takarada T. Disruption of Bmal1 Impairs Blood-Brain Barrier Integrity via Pericyte Dysfunction. J Neurosci 2017; 37:10052-10062. [PMID: 28912161 PMCID: PMC6596539 DOI: 10.1523/jneurosci.3639-16.2017] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Revised: 09/04/2017] [Indexed: 01/13/2023] Open
Abstract
Circadian rhythm disturbances are well established in neurological diseases. However, how these disruptions cause homeostatic imbalances remains poorly understood. Brain and muscle aryl hydrocarbon receptor nuclear translocator-like protein 1 (Bmal1) is a major circadian clock transcriptional activator, and Bmal1 deficiency in male Bmal1nestin-/- mice induced marked astroglial activation without affecting the number of astrocytes in the brain and spinal cord. Bmal1 deletion caused blood-brain barrier (BBB) hyperpermeability with an age-dependent loss of pericyte coverage of blood vessels in the brain. Using Nestin-green fluorescent protein (GFP) transgenic mice, we determined that pericytes are Nestin-GFP+ in the adult brain. Bmal1 deletion caused Nestin-GFP+ pericyte dysfunction, including the downregulation of platelet-derived growth factor receptor β (PDGFRβ), a protein necessary for maintaining BBB integrity. Knockdown of Bmal1 downregulated PDGFRβ transcription in the brain pericyte cell line. Thus, the circadian clock component Bmal1 maintains BBB integrity via regulating pericytes.SIGNIFICANCE STATEMENT Circadian rhythm disturbances may play a role in neurodegenerative disorders, such as Alzheimer's disease. Our results revealed that one of the circadian clock components maintains the integrity of the blood-brain barrier (BBB) by regulating vascular-embedded pericytes. These cells were recently identified as a vital component for the control of BBB permeability and cerebral blood flow. Our present study demonstrates the involvement of circadian clock component Bmal1 in BBB homeostasis and highlights the role of Bmal1 dysfunction in multiple neurological diseases.
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Affiliation(s)
- Ryota Nakazato
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Kenji Kawabe
- Department of Regenerative Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan
| | - Daisuke Yamada
- Department of Regenerative Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan
| | - Shinsuke Ikeno
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Michihiro Mieda
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University, Kanazawa, Ishikawa 920-8640, Japan, and
| | - Shigeki Shimba
- Department of Health Science, College of Pharmacy, Nihon University, Chiba 274-8555, Japan
| | - Eiichi Hinoi
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Yukio Yoneda
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Takeshi Takarada
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan,
- Department of Regenerative Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan
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6
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Osgood D, Miller MC, Messier AA, Gonzalez L, Silverberg GD. Aging alters mRNA expression of amyloid transporter genes at the blood-brain barrier. Neurobiol Aging 2017; 57:178-185. [PMID: 28654861 PMCID: PMC5728118 DOI: 10.1016/j.neurobiolaging.2017.05.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 05/11/2017] [Accepted: 05/12/2017] [Indexed: 12/22/2022]
Abstract
Decreased clearance of potentially toxic metabolites, due to aging changes, likely plays a significant role in the accumulation of amyloid-beta (Aβ) peptides and other macromolecules in the brain of the elderly and in the patients with Alzheimer's disease (AD). Aging is the single most important risk factor for AD development. Aβ transport receptor proteins expressed at the blood-brain barrier are significantly altered with age: the efflux transporters lipoprotein receptor-related protein 1 and P-glycoprotein are reduced, whereas the influx transporter receptor for advanced glycation end products is increased. These receptors play an important role in maintaining brain biochemical homeostasis. We now report that, in a rat model of aging, gene transcription is altered in aging, as measured by Aβ receptor gene messenger RNA (mRNA) at 3, 6, 9, 12, 15, 20, 30, and 36 months. Gene mRNA expression from isolated cerebral microvessels was measured by quantitative polymerase chain reaction. Lipoprotein receptor-related protein 1 and P-glycoprotein mRNA were significantly reduced in aging, and receptor for advanced glycation end products was increased, in parallel with the changes seen in receptor protein expression. Transcriptional changes appear to play a role in aging alterations in blood-brain barrier receptor expression and Aβ accumulation.
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Affiliation(s)
- Doreen Osgood
- Department of Neurosurgery, Warren Alpert Medical School, Brown University, Providence, RI, USA; The Aldrich Laboratories, Rhode Island Hospital, Providence, RI, USA
| | - Miles C Miller
- Department of Neurosurgery, Warren Alpert Medical School, Brown University, Providence, RI, USA; The Aldrich Laboratories, Rhode Island Hospital, Providence, RI, USA
| | - Arthur A Messier
- Department of Neurosurgery, Warren Alpert Medical School, Brown University, Providence, RI, USA; The Aldrich Laboratories, Rhode Island Hospital, Providence, RI, USA
| | - Liliana Gonzalez
- Department of Computer Science and Statistics, University of Rhode Island, Kingston, RI, USA
| | - Gerald D Silverberg
- Department of Neurosurgery, Warren Alpert Medical School, Brown University, Providence, RI, USA; The Aldrich Laboratories, Rhode Island Hospital, Providence, RI, USA.
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7
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Abstract
Exosome-mediated intercellular communication has become an emerging field of human health and diseases. A recent study published by Cell Research reports that in zebrafish neurons can remotely regulate blood-brain barrier integrity by delivering miR-132 through secretion of exosomes.
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8
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Gao X, Wang YC, Liu Y, Yue Q, Liu Z, Ke M, Zhao S, Li C. Nanoagonist-mediated endothelial tight junction opening: A strategy for safely increasing brain drug delivery in mice. J Cereb Blood Flow Metab 2017; 37:1410-1424. [PMID: 27342320 PMCID: PMC5453461 DOI: 10.1177/0271678x16656198] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Even though opening endothelial tight junctions is an efficient way to up-regulate brain drug delivery, the extravasation of blood-borne components from the compromised tight junctions can result in adverse consequences such as edema and neuronal injuries. In this work, we developed a nanoagonist that temporarily opened tight junctions by signaling adenosine 2A receptor, a type of G protein-coupled receptor expressed on brain capillary endothelial cells. Magnetic resonance imaging demonstrated remarkable blood-brain barrier permeability enhancements and significantly increased brain uptakes of both small molecular and macromolecular paramagnetic agents after nanoagonist administration. Gamma ray imaging and transmission electron microscope observed tight junction opening followed by spontaneous recovery after nanoagonist treatment. Immunofluorescence staining showed the unspoiled basal membrane, pericytes and astrocyte endfeet that enwrapped the vascular endothelium. Importantly, edema, apoptosis and neuronal injuries observed after hypertonic agent mediated tight junction-opening were not observed after nanoagonist intervention. The uncompromised neurovascular units may prevent the leakage of blood-borne constituents into brain parenchyma and accelerate tight junction recovery. Considering blood-brain barrier impermeability is a major obstacle in the treatment of central nervous system diseases, nanoagonist-mediated tight junction opening provides a promising strategy to enhance brain drug delivery with minimized adverse effects.
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Affiliation(s)
- Xihui Gao
- 1 Key Laboratory of Smart Drug Delivery, Ministry of Education, School of Pharmacy, Fudan University, Shanghai, China
| | - Yuan-Cheng Wang
- 2 Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School of Southeast University, Nanjing, China
| | - Yikang Liu
- 3 Department of Biomedical Engineering, The Pennsylvania State University, Philadelphia, PA, USA
| | - Qi Yue
- 4 Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China
| | - Zining Liu
- 1 Key Laboratory of Smart Drug Delivery, Ministry of Education, School of Pharmacy, Fudan University, Shanghai, China
| | - Mengjing Ke
- 1 Key Laboratory of Smart Drug Delivery, Ministry of Education, School of Pharmacy, Fudan University, Shanghai, China
| | - Shengyuan Zhao
- 1 Key Laboratory of Smart Drug Delivery, Ministry of Education, School of Pharmacy, Fudan University, Shanghai, China
| | - Cong Li
- 1 Key Laboratory of Smart Drug Delivery, Ministry of Education, School of Pharmacy, Fudan University, Shanghai, China
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9
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Rustenhoven J, Jansson D, Smyth LC, Dragunow M. Brain Pericytes As Mediators of Neuroinflammation. Trends Pharmacol Sci 2017; 38:291-304. [DOI: 10.1016/j.tips.2016.12.001] [Citation(s) in RCA: 156] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 12/01/2016] [Accepted: 12/01/2016] [Indexed: 01/03/2023]
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10
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Park JC, Baik SH, Han SH, Cho HJ, Choi H, Kim HJ, Choi H, Lee W, Kim DK, Mook-Jung I. Annexin A1 restores Aβ 1-42 -induced blood-brain barrier disruption through the inhibition of RhoA-ROCK signaling pathway. Aging Cell 2017; 16:149-161. [PMID: 27633771 PMCID: PMC5242298 DOI: 10.1111/acel.12530] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/18/2016] [Indexed: 12/15/2022] Open
Abstract
The blood–brain barrier (BBB) is composed of brain capillary endothelial cells and has an important role in maintaining homeostasis of the brain separating the blood from the parenchyma of the central nervous system (CNS). It is widely known that disruption of the BBB occurs in various neurodegenerative diseases, including Alzheimer's disease (AD). Annexin A1 (ANXA1), an anti‐inflammatory messenger, is expressed in brain endothelial cells and regulates the BBB integrity. However, its role and mechanism for protecting BBB in AD have not been identified. We found that β‐Amyloid 1‐42 (Aβ42)‐induced BBB disruption was rescued by human recombinant ANXA1 (hrANXA1) in the murine brain endothelial cell line bEnd.3. Also, ANXA1 was decreased in the bEnd.3 cells, the capillaries of 5XFAD mice, and the human serum of patients with AD. To find out the mechanism by which ANXA1 recovers the BBB integrity in AD, the RhoA‐ROCK signaling pathway was examined in both Aβ42‐treated bEnd.3 cells and the capillaries of 5XFAD mice as RhoA was activated in both cases. RhoA inhibitors alleviated Aβ42‐induced BBB disruption and constitutively overexpressed RhoA‐GTP (active form of RhoA) attenuated the protective effect of ANXA1. When pericytes were cocultured with bEnd.3 cells, Aβ42‐induced RhoA activation of bEnd.3 cells was inhibited by the secretion of ANXA1 from pericytes. Taken together, our results suggest that ANXA1 restores Aβ42‐induced BBB disruption through inhibition of RhoA‐ROCK signaling pathway and we propose ANXA1 as a therapeutic reagent, protecting against the breakdown of the BBB in AD.
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Affiliation(s)
- Jong-Chan Park
- Department of Biochemistry and Biomedical Sciences; College of Medicine; Seoul National University; Seoul 110-799 Korea
| | - Sung Hoon Baik
- Department of Biochemistry and Biomedical Sciences; College of Medicine; Seoul National University; Seoul 110-799 Korea
| | - Sun-Ho Han
- Department of Biochemistry and Biomedical Sciences; College of Medicine; Seoul National University; Seoul 110-799 Korea
| | - Hyun Jin Cho
- Department of Biochemistry and Biomedical Sciences; College of Medicine; Seoul National University; Seoul 110-799 Korea
| | - Hyunjung Choi
- Department of Biochemistry and Biomedical Sciences; College of Medicine; Seoul National University; Seoul 110-799 Korea
| | - Haeng Jun Kim
- Department of Biochemistry and Biomedical Sciences; College of Medicine; Seoul National University; Seoul 110-799 Korea
| | - Heesun Choi
- Department of Biochemistry and Biomedical Sciences; College of Medicine; Seoul National University; Seoul 110-799 Korea
| | - Wonik Lee
- Department of Biochemistry and Biomedical Sciences; College of Medicine; Seoul National University; Seoul 110-799 Korea
| | - Dong Kyu Kim
- Department of Biochemistry and Biomedical Sciences; College of Medicine; Seoul National University; Seoul 110-799 Korea
| | - Inhee Mook-Jung
- Department of Biochemistry and Biomedical Sciences; College of Medicine; Seoul National University; Seoul 110-799 Korea
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11
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Lee LL, Aung HH, Wilson DW, Anderson SE, Rutledge JC, Rutkowsky JM. Triglyceride-rich lipoprotein lipolysis products increase blood-brain barrier transfer coefficient and induce astrocyte lipid droplets and cell stress. Am J Physiol Cell Physiol 2017; 312:C500-C516. [PMID: 28077357 DOI: 10.1152/ajpcell.00120.2016] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 01/06/2017] [Accepted: 01/09/2017] [Indexed: 12/19/2022]
Abstract
Elevation of blood triglycerides, primarily as triglyceride-rich lipoproteins (TGRL), has been linked to cerebrovascular inflammation, vascular dementia, and Alzheimer's disease (AD). Brain microvascular endothelial cells and astrocytes, two cell components of the neurovascular unit, participate in controlling blood-brain barrier (BBB) permeability and regulating neurovascular unit homeostasis. Our studies showed that infusion of high physiological concentrations of TGRL lipolysis products (TGRL + lipoprotein lipase) activate and injure brain endothelial cells and transiently increase the BBB transfer coefficient (Ki = permeability × surface area/volume) in vivo. However, little is known about how blood lipids affect astrocyte lipid accumulation and inflammation. To address this, we first demonstrated TGRL lipolysis products increased lipid droplet formation in cultured normal human astrocytes. We then evaluated the transcriptional pathways activated in astrocytes by TGRL lipolysis products and found upregulated stress and inflammatory-related genes including activating transcription factor 3 (ATF3), macrophage inflammatory protein-3α (MIP-3α), growth differentiation factor-15 (GDF15), and prostaglandin-endoperoxide synthase 2 (COX2). TGRL lipolysis products also activated the JNK/cJUN/ATF3 pathway, induced endoplasmic reticulum stress protein C/EBP homologous protein (CHOP), and the NF-κB pathway, while increasing secretion of MIP-3α, GDF15, and IL-8. Thus our results demonstrate TGRL lipolysis products increase the BBB transfer coefficient (Ki), induce astrocyte lipid droplet formation, activate cell stress pathways, and induce secretion of inflammatory cytokines. Our observations are consistent with evidence for lipid-induced neurovascular injury and inflammation, and we, therefore, speculate that lipid-induced astrocyte injury could play a role in cognitive decline.
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Affiliation(s)
- Linda L Lee
- Department of Internal Medicine, University of California, Davis, California
| | - Hnin H Aung
- Department of Internal Medicine, University of California, Davis, California
| | - Dennis W Wilson
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, California; and
| | - Steven E Anderson
- Department of Physiology and Membrane Biology, University of California, Davis, California
| | - John C Rutledge
- Department of Internal Medicine, University of California, Davis, California
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12
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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: 284] [Impact Index Per Article: 40.6] [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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13
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Transport of haloacids across biological membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:3061-3070. [PMID: 27668346 DOI: 10.1016/j.bbamem.2016.09.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 09/20/2016] [Accepted: 09/21/2016] [Indexed: 12/28/2022]
Abstract
Haloacids are considered to be environmental pollutants, but some of them have also been tested in clinical research. The way that haloacids are transported across biological membranes is important for both biodegradation and drug delivery purposes. In this review, we will first summarize putative haloacids transporters and the information about haloacids transport when studying carboxylates transporters. We will then introduce MCT1 and SLC5A8, which are respective transporter for antitumor agent 3-bromopyruvic acid and dichloroacetic acid, and monochloroacetic acid transporters Deh4p and Dehp2 from a haloacids-degrading bacterium. Phylogenetic analysis of these haloacids transporters and other monocarboxylate transporters reveals their evolutionary relationships. Haloacids transporters are not studied to the extent that they deserve compared with their great application potentials, thus future inter-discipline research are desired to better characterize their transport mechanisms for potential applications in both environmental and clinical fields.
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14
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Do TM, Dodacki A, Alata W, Calon F, Nicolic S, Scherrmann JM, Farinotti R, Bourasset F. Age-Dependent Regulation of the Blood-Brain Barrier Influx/Efflux Equilibrium of Amyloid-β Peptide in a Mouse Model of Alzheimer's Disease (3xTg-AD). J Alzheimers Dis 2016; 49:287-300. [PMID: 26484906 DOI: 10.3233/jad-150350] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The involvement of transporters located at the blood-brain barrier (BBB) has been suggested in the control of cerebral Aβ levels, and thereby in Alzheimer's disease (AD). However, little is known about the regulation of these transporters at the BBB in animal models of AD. In this study, we investigated the BBB expression of Aβ influx (Rage) and efflux (Abcb1-Abcg2-Abcg4-Lrp-1) transporters and cholesterol transporter (Abca1) in 3-18-month-old 3xTg-AD and control mice. The age-dependent effect of BBB transporters regulation on the brain uptake clearance (Clup) of [3H]cholesterol and [3H]Aβ1 - 40 was then evaluated in these mice, using the in situ brain perfusion technique. Our data suggest that transgenes expression led to the BBB increase in Aβ influx receptor (Rage) and decrease in efflux receptor (Lrp-1). Our data also indicate that mice have mechanisms counteracting this increased net influx. Indeed, Abcg4 and Abca1 are up regulated in 3- and 3/6-month-old 3xTg-AD mice, respectively. Our data show that the balance between the BBB influx and efflux of Aβ is maintained in 3 and 6-month-old 3xTg-AD mice, suggesting that Abcg4 and Abca1 control the efflux of Aβ through the BBB by a direct (Abcg4) or indirect (Abca1) mechanism. At 18 months, the BBB Aβ efflux is significantly increased in 3xTg-AD mice compared to controls. This could result from the significant up-regulation of both Abcg2 and Abcb1 in 3xTg-AD mice compared to control mice. Thus, age-dependent regulation of several Aβ and cholesterol transporters at the BBB could ultimately limit the brain accumulation of Aβ.
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Affiliation(s)
- Tuan Minh Do
- Laboratoire de Pharmacie Clinique et pharmacocinétique, EA 4123, Université Paris-Sud 11, Faculté de Pharmacie, Châtenay-Malabry, France
| | - Agnès Dodacki
- Inserm UMR-S1144, Paris, F 75006, France.,Université Paris Descartes, Paris, France.,Université Paris Diderot, Paris, France
| | - Wael Alata
- Faculty of Pharmacy, Laval University, Quebec (QC), Canada
| | - Frederic Calon
- Faculty of Pharmacy, Laval University, Quebec (QC), Canada
| | - Sophie Nicolic
- Inserm UMR-S1144, Paris, F 75006, France.,Université Paris Descartes, Paris, France.,Université Paris Diderot, Paris, France
| | - Jean-Michel Scherrmann
- Inserm UMR-S1144, Paris, F 75006, France.,Université Paris Descartes, Paris, France.,Université Paris Diderot, Paris, France
| | - Robert Farinotti
- Laboratoire de Pharmacie Clinique et pharmacocinétique, EA 4123, Université Paris-Sud 11, Faculté de Pharmacie, Châtenay-Malabry, France
| | - Fanchon Bourasset
- Inserm UMR-S1144, Paris, F 75006, France.,Université Paris Descartes, Paris, France.,Université Paris Diderot, Paris, France
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15
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Montagne A, Nation DA, Pa J, Sweeney MD, Toga AW, Zlokovic BV. Brain imaging of neurovascular dysfunction in Alzheimer's disease. Acta Neuropathol 2016; 131:687-707. [PMID: 27038189 PMCID: PMC5283382 DOI: 10.1007/s00401-016-1570-0] [Citation(s) in RCA: 143] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 03/21/2016] [Accepted: 03/23/2016] [Indexed: 11/29/2022]
Abstract
Neurovascular dysfunction, including blood-brain barrier (BBB) breakdown and cerebral blood flow (CBF) dysregulation and reduction, are increasingly recognized to contribute to Alzheimer's disease (AD). The spatial and temporal relationships between different pathophysiological events during preclinical stages of AD, including cerebrovascular dysfunction and pathology, amyloid and tau pathology, and brain structural and functional changes remain, however, still unclear. Recent advances in neuroimaging techniques, i.e., magnetic resonance imaging (MRI) and positron emission tomography (PET), offer new possibilities to understand how the human brain works in health and disease. This includes methods to detect subtle regional changes in the cerebrovascular system integrity. Here, we focus on the neurovascular imaging techniques to evaluate regional BBB permeability (dynamic contrast-enhanced MRI), regional CBF changes (arterial spin labeling- and functional-MRI), vascular pathology (structural MRI), and cerebral metabolism (PET) in the living human brain, and examine how they can inform about neurovascular dysfunction and vascular pathophysiology in dementia and AD. Altogether, these neuroimaging approaches will continue to elucidate the spatio-temporal progression of vascular and neurodegenerative processes in dementia and AD and how they relate to each other.
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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
| | - Daniel A Nation
- Department of Psychology, University of Southern California, Los Angeles, CA, 90089, USA
| | - Judy Pa
- Department of Neurology, Institute for Neuroimaging and Informatics, University of Southern California, Los Angeles, CA, 90089, 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
| | - Arthur W Toga
- Department of Neurology, Institute for Neuroimaging and Informatics, 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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16
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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: 360] [Impact Index Per Article: 45.0] [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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17
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Burgess A, Shah K, Hough O, Hynynen K. Focused ultrasound-mediated drug delivery through the blood-brain barrier. Expert Rev Neurother 2016; 15:477-91. [PMID: 25936845 DOI: 10.1586/14737175.2015.1028369] [Citation(s) in RCA: 149] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Despite recent advances in blood-brain barrier (BBB) research, it remains a significant hurdle for the pharmaceutical treatment of brain diseases. Focused ultrasound (FUS) is one method to transiently increase permeability of the BBB to promote drug delivery to specific brain regions. An introduction to the BBB and a brief overview of the methods, which can be used to circumvent the BBB to promote drug delivery, is provided. In particular, we discuss the advantages and limitations of FUS technology and the efficacy of FUS-mediated drug delivery in models of disease. MRI for targeting and evaluating FUS treatments, combined with administration of microbubbles, allows for transient, reproducible BBB opening. The integration of a real-time acoustic feedback controller has improved treatment safety. Successful clinical translation of FUS has the potential to transform the treatment of brain disease worldwide without requiring the development of new pharmaceutical agents.
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Affiliation(s)
- Alison Burgess
- Physical Sciences, Sunnybrook Research Institute, 2075 Bayview Ave, S665, Toronto, ON M4N 3M5, Canada
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18
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Zhao H, Li N, Wang Q, Cheng X, Li X, Liu T. Resveratrol decreases the insoluble Aβ1–42 level in hippocampus and protects the integrity of the blood–brain barrier in AD rats. Neuroscience 2015; 310:641-9. [DOI: 10.1016/j.neuroscience.2015.10.006] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 09/08/2015] [Accepted: 10/03/2015] [Indexed: 10/22/2022]
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19
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Ramanathan A, Nelson AR, Sagare AP, Zlokovic BV. Impaired vascular-mediated clearance of brain amyloid beta in Alzheimer's disease: the role, regulation and restoration of LRP1. Front Aging Neurosci 2015; 7:136. [PMID: 26236233 PMCID: PMC4502358 DOI: 10.3389/fnagi.2015.00136] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 07/02/2015] [Indexed: 12/12/2022] Open
Abstract
Amyloid beta (Aβ) homeostasis in the brain is governed by its production and clearance mechanisms. An imbalance in this homeostasis results in pathological accumulations of cerebral Aβ, a characteristic of Alzheimer’s disease (AD). While Aβ may be cleared by several physiological mechanisms, a major route of Aβ clearance is the vascular-mediated removal of Aβ from the brain across the blood-brain barrier (BBB). Here, we discuss the role of the predominant Aβ clearance protein—low-density lipoprotein receptor-related protein 1 (LRP1)—in the efflux of Aβ from the brain. We also outline the multiple factors that influence the function of LRP1-mediated Aβ clearance, such as its expression, shedding, structural modification and transcriptional regulation by other genes. Finally, we summarize approaches aimed at restoring LRP1-mediated Aβ clearance from the brain.
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Affiliation(s)
- Anita Ramanathan
- Department of Physiology and Biophysics, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California Los Angeles, CA, USA
| | - Amy R Nelson
- 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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20
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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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21
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Chiu C, Miller MC, Monahan R, Osgood DP, Stopa EG, Silverberg GD. P-glycoprotein expression and amyloid accumulation in human aging and Alzheimer's disease: preliminary observations. Neurobiol Aging 2015; 36:2475-82. [PMID: 26159621 DOI: 10.1016/j.neurobiolaging.2015.05.020] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 04/22/2015] [Accepted: 05/29/2015] [Indexed: 11/16/2022]
Abstract
P-glycoprotein (P-gp), part of the blood-brain barrier, limits drug access to the brain and is the target for therapies designed to improve drug penetration. P-gp also extrudes brain amyloid-beta (Aβ). Accumulation of Aβ is a hallmark of Alzheimer's disease (AD). Aβ accumulates in normal aging and in AD primarily due to decreased Aβ clearance. This is a preliminary report on the relative protein and messenger RNA expression of P-gp in human brains, ages 20-100 years, including AD subjects. In these preliminary studies, cortical endothelial P-gp expression decreased in AD compared with controls (p < 0.001). Trends in P-gp expression in human aging are similar to aging rats. Microvessel P-gp messenger RNA remained unchanged with aging and AD. Aβ plaques were found in 42.8% of normal subjects (54.5% of those older than 50 years). A qualitative analysis showed that P-gp expression is lower than the group mean in subjects older than 75 years but increased if younger. Decreased P-gp expression may be related to Aβ plaques in aging and AD. Downregulating P-gp to allow pharmaceuticals into the central nervous system may increase Aβ accumulation.
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Affiliation(s)
- Catherine Chiu
- Department of Neurosurgery, Warren Alpert Medical School, Brown University and Aldrich Neurosurgery Research Laboratories, Rhode Island Hospital, Providence, RI, USA
| | - Miles C Miller
- Department of Neurosurgery, Warren Alpert Medical School, Brown University and Aldrich Neurosurgery Research Laboratories, Rhode Island Hospital, Providence, RI, USA
| | - Renée Monahan
- Department of Pathology, Division of Neuropathology, Warren Alpert Medical School, Brown University and Rhode Island Hospital, Providence, RI, USA
| | - Doreen P Osgood
- Department of Neurosurgery, Warren Alpert Medical School, Brown University and Aldrich Neurosurgery Research Laboratories, Rhode Island Hospital, Providence, RI, USA
| | - Edward G Stopa
- Department of Neurosurgery, Warren Alpert Medical School, Brown University and Aldrich Neurosurgery Research Laboratories, Rhode Island Hospital, Providence, RI, USA; Department of Pathology, Division of Neuropathology, Warren Alpert Medical School, Brown University and Rhode Island Hospital, Providence, RI, USA
| | - Gerald D Silverberg
- Department of Neurosurgery, Warren Alpert Medical School, Brown University and Aldrich Neurosurgery Research Laboratories, Rhode Island Hospital, Providence, RI, USA.
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22
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Okada R, Wu Z, Zhu A, Ni J, Zhang J, Yoshimine Y, Peters C, Saftig P, Nakanishi H. Cathepsin D deficiency induces oxidative damage in brain pericytes and impairs the blood-brain barrier. Mol Cell Neurosci 2014; 64:51-60. [PMID: 25496868 DOI: 10.1016/j.mcn.2014.12.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 11/24/2014] [Accepted: 12/09/2014] [Indexed: 01/03/2023] Open
Abstract
Recent evidence suggests that peripheral blood mononuclear cells (PBMCs) contribute to the pathogenesis of neuropathological changes in patients with neuronal ceroid lipofuscinosis (NCL) and lysosomal storage diseases. In order to examine the possible increase in the permeability of the blood-brain-barrier (BBB) and resultant infiltration of PBMCs due to cathepsin D (CatD) deficiency, a process underlying the onset of congenital NCL, we examined structural changes in brain vessels in CatD-/- mice. Consequently, the mean diameter of the brain vessels in the cerebral cortex on postnatal day 24 (P24) was significantly larger in CatD-/- mice than in wild-type mice. Furthermore, the mean number of brain pericytes in CatD-/- mice began to decline significantly on P16 and almost disappeared on P24, and oxidative DNA damage was first detected in brain pericytes on P12. Examinations with electron microscopy revealed that brain pericytes were laden with dense granular bodies, cytoplasmic vacuoles and lipid droplets. The infiltration of PBMCs characterized by segmented nucleus laden with dense granular bodies was also noted in the cerebral cortex of CatD-/- mice. When primary cultured microglia prepared from enhanced green fluorescent protein (GFP)-expressing transgenic rats were injected into the common carotid artery, GFP-positive microglia were detected in the brain parenchyma of CatD-/-, but not wild-type, mice. Moreover, pepstatin A, a specific aspartic protease inhibitor, induced mitochondria-derived reactive oxygen species (ROS) production in the isolated brain pericytes, which decreased the cell viability. These observations suggest that increased lysosomal storage due to CatD deficiency causes oxidative damage in brain pericytes, subsequently resulting in an increased vessel diameter, enhanced permeability of the BBB and the infiltration of PBMCs. Therefore, protecting brain pericytes against lysosomal storage-induced oxidative stress may represent an alternative treatment strategy for congenital NCL.
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Affiliation(s)
- Ryo Okada
- Department of Aging Science and Pharmacology, Faculty of Dental Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Zhou Wu
- Department of Aging Science and Pharmacology, Faculty of Dental Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Aiqin Zhu
- Institution of Geriatric Qinghai Provincial Hospital, Shining, 810007, China
| | - Junjun Ni
- Department of Aging Science and Pharmacology, Faculty of Dental Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Jingqi Zhang
- Division of Oral Biological Sciences, Department of Molecular Cell Biology & Oral Anatomy, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Yoshito Yoshimine
- Department of Endodontology and Operative Dentistry, Faculty of Dental Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Christoph Peters
- Instutute für Molekuläre Medizin und Zellforschung, Albert-Ludwigs-Universität, Freiburg D-79104, Germany
| | - Paul Saftig
- Department of Biochemistry, University of Kiel, D-24098 Kiel, Germany
| | - Hiroshi Nakanishi
- Department of Aging Science and Pharmacology, Faculty of Dental Sciences, Kyushu University, Fukuoka 812-8582, Japan.
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23
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Jin X, Liang B, Chen Z, Liu X, Zhang Z. The Dynamic Changes of Capillary Permeability and Upregulation of VEGF in Rats Following Radiation-Induced Brain Injury. Microcirculation 2014; 21:171-7. [PMID: 25279427 DOI: 10.1111/micc.12103] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 10/25/2013] [Indexed: 12/01/2022]
Affiliation(s)
- Xuelong Jin
- Department of Physiology; Tianjin Medical University; Tianjin China
| | - Bin Liang
- Department of Physiology; Tianjin Medical University; Tianjin China
| | - Zequn Chen
- Department of Physiology; Tianjin Medical University; Tianjin China
| | - Xingju Liu
- Department of Physiology; Tianjin Medical University; Tianjin China
| | - Zhiwen Zhang
- Department of Neurosurgery; First Affiliated Hospital of Chinese PLA General Hospital; Beijing China
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24
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Takeda S, Sato N, Ikimura K, Nishino H, Rakugi H, Morishita R. Increased blood-brain barrier vulnerability to systemic inflammation in an Alzheimer disease mouse model. Neurobiol Aging 2013; 34:2064-70. [PMID: 23561508 DOI: 10.1016/j.neurobiolaging.2013.02.010] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2012] [Revised: 01/20/2013] [Accepted: 02/15/2013] [Indexed: 01/05/2023]
Abstract
Behavioral and psychological problems are often observed in patients with dementia such as that associated with Alzheimer disease, and these noncognitive symptoms place an extremely heavy burden on the family and caregivers. Although it is well know that these symptoms often are triggered by infection of peripheral organs, the underlying mechanisms for these pathological conditions are still unclear. In this study, using an Alzheimer amyloid precursor protein (APP)-transgenic mouse, we analyzed behavioral changes and brain inflammatory response induced by peripheral administration of lipopolysaccharide. Application of a unique in vivo microdialysis system revealed that the increase in brain inflammatory cytokine (interleukin-6) level was significantly higher in APP-Tg than in wild-type mice after peripheral lipopolysaccharide injection, which was associated with more severe sickness behaviors. The blood-brain barrier became more permeable in APP-Tg mice during peripherally evoked inflammation, suggesting the increased vulnerability of the blood-brain barrier to inflammation in this animal model of Alzheimer's disease. These findings might provide insight into the pathogenesis of noncognitive symptoms in dementia and a basis to develop new therapeutic treatments for them.
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Affiliation(s)
- Shuko Takeda
- Department of Clinical Gene Therapy, Graduate School of Medicine, Osaka University, Yamadaoka, Suita, Japan
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25
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Guan J, Pavlovic D, Dalkie N, Waldvogel HJ, O'Carroll SJ, Green CR, Nicholson LFB. Vascular degeneration in Parkinson's disease. Brain Pathol 2013; 23:154-64. [PMID: 22897695 PMCID: PMC8029297 DOI: 10.1111/j.1750-3639.2012.00628.x] [Citation(s) in RCA: 124] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 08/09/2012] [Indexed: 12/24/2022] Open
Abstract
Vascular degeneration plays a significant role in contributing to neurodegenerative conditions such as Alzheimer's disease. Our understanding of the vascular components in Parkinson's disease (PD) is however limited. We have examined the vascular morphology of human brain tissue from both PD and the control cases using immunohistochemical staining and image analysis. The degenerative morphology seen in PD cases included the formation of endothelial cell "clusters," which may be contributed by the fragmentation of capillaries. When compared to the control cases, the capillaries of PDs were less in number (P < 0.001), shorter in length (P < 0.001) and larger in diameter (P < 0.01) with obvious damage to the capillary network evidenced by less branching (P < 0.001). The level of degeneration seen in the caudate nucleus was also seen in the age-matched control cases. Vessel degeneration associated with PD was, however, found in multiple brain regions, but particularly in the substantia nigra, middle frontal cortex and brain stem nuclei. The data suggest that vascular degeneration could be an additional contributing factor to the progression of PD. Thus, treatments that prevent vascular degeneration and improve vascular remodeling may be a novel target for the treatment of PD.
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Affiliation(s)
- Jian Guan
- Liggins Institute, University of Auckland, Auckland, New Zealand.
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26
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Zlokovic BV. A gliovascular idea for the white matter repair? J Neurochem 2013; 125:172-4. [PMID: 23441580 DOI: 10.1111/jnc.12174] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 01/28/2013] [Indexed: 12/23/2022]
Affiliation(s)
- Berislav V Zlokovic
- Center for Neurodegeneration and Regeneration, Zilkha Neurogenetic Institute, and Department of Physiology and Biophysics, University of Southern California, Los Angeles, CA, USA
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27
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Shimizu F, Sano Y, Tominaga O, Maeda T, Abe MA, Kanda T. Advanced glycation end-products disrupt the blood-brain barrier by stimulating the release of transforming growth factor-β by pericytes and vascular endothelial growth factor and matrix metalloproteinase-2 by endothelial cells in vitro. Neurobiol Aging 2013; 34:1902-12. [PMID: 23428182 DOI: 10.1016/j.neurobiolaging.2013.01.012] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 01/14/2013] [Accepted: 01/20/2013] [Indexed: 01/31/2023]
Abstract
Diabetic encephalopathy is now accepted as an important complication of diabetes. The breakdown of the blood-brain barrier (BBB) is associated with dementia in patients with type 2 diabetes mellitus (T2DM). The purpose of this study was to identify the possible mechanisms responsible for the disruption of the BBB after exposure to advanced glycation end-products (AGEs). We investigated the effect of AGEs on the basement membrane and the barrier property of the BBB by Western blot analysis, using our newly established lines of human brain microvascular endothelial cell (BMEC), pericytes, and astrocytes. AGEs reduced the expression of claudin-5 in BMECs by increasing the autocrine signaling through vascular endothelial growth factor (VEGF) and matrix metalloproteinase-2 (MMP-2) secreted by the BMECs themselves. Furthermore, AGEs increased the amount of fibronectin in the pericytes through a similar up-regulation of the autocrine transforming growth factor (TGF)-β released by pericytes. These results indicated that AGEs induce basement membrane hypertrophy of the BBB by increasing the degree of autocrine TGF-β signaling by pericytes, and thereby disrupt the BBB through the up-regulation of VEGF and MMP-2 in BMECs under diabetic conditions.
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Affiliation(s)
- Fumitaka Shimizu
- Department of Neurology and Clinical Neuroscience, Yamaguchi University Graduate School of Medicine, Ube, Japan
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28
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Winkler EA, Sengillo JD, Sullivan JS, Henkel JS, Appel SH, Zlokovic BV. Blood-spinal cord barrier breakdown and pericyte reductions in amyotrophic lateral sclerosis. Acta Neuropathol 2013; 125:111-20. [PMID: 22941226 PMCID: PMC3535352 DOI: 10.1007/s00401-012-1039-8] [Citation(s) in RCA: 234] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 08/21/2012] [Accepted: 08/23/2012] [Indexed: 12/12/2022]
Abstract
The blood-brain barrier and blood-spinal cord barrier (BSCB) limit the entry of plasma components and erythrocytes into the central nervous system (CNS). Pericytes play a key role in maintaining blood-CNS barriers. The BSCB is damaged in patients with amyotrophic lateral sclerosis (ALS). Moreover, transgenic ALS rodents and pericyte-deficient mice develop BSCB disruption with erythrocyte extravasation preceding motor neuron dysfunction. Here, we studied whether BSCB disruption with erythrocyte extravasation and pericyte loss are present in human ALS. We show that 11 of 11 cervical cords from ALS patients, but 0 of 5 non-neurodegenerative disorders controls, possess perivascular deposits of erythrocyte-derived hemoglobin and hemosiderin typically 10-50 μm in diameter suggestive of erythrocyte extravasation. Immunostaining for CD235a, a specific marker for erythrocytes, confirmed sporadic erythrocyte extravasation in ALS, but not controls. Quantitative analysis revealed a 3.1-fold increase in perivascular hemoglobin deposits in ALS compared to controls showing hemoglobin confined within the vascular lumen, which correlated with 2.5-fold increase in hemosiderin deposits (r = 0.82, p < 0.01). Spinal cord parenchymal accumulation of plasma-derived immunoglobulin G, fibrin and thrombin was demonstrated in ALS, but not controls. Immunostaining for platelet-derived growth factor receptor-β, a specific marker for CNS pericytes, indicated a 54 % (p < 0.01) reduction in pericyte number in ALS patients compared to controls. Pericyte reduction correlated negatively with the magnitude of BSCB damage as determined by hemoglobin abundance (r = -0.75, p < 0.01). Thus, the BSCB disruption with erythrocyte extravasation and pericyte reductions is present in ALS. Whether similar findings occur in motor cortex and affected brainstem motor nuclei remain to be seen.
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Affiliation(s)
- Ethan A. Winkler
- Center for Neurodegeneration and Regeneration, Zilkha Neurogenetic Institute, University of Southern California, Room: 101, 1501 San Pablo Street, Los Angeles, CA 90089 USA
| | - Jesse D. Sengillo
- Center for Neurodegeneration and Regeneration, Zilkha Neurogenetic Institute, University of Southern California, Room: 101, 1501 San Pablo Street, Los Angeles, CA 90089 USA
| | - John S. Sullivan
- Center for Neurodegeneration and Regeneration, Zilkha Neurogenetic Institute, University of Southern California, Room: 101, 1501 San Pablo Street, Los Angeles, CA 90089 USA
| | - Jenny S. Henkel
- Department of Neurology, Methodist Neurological Institute, The Methodist Hospital Research Institute, The Methodist Hospital, Houston, TX USA
| | - Stanley H. Appel
- Department of Neurology, Methodist Neurological Institute, The Methodist Hospital Research Institute, The Methodist Hospital, Houston, TX USA
| | - Berislav V. Zlokovic
- Center for Neurodegeneration and Regeneration, Zilkha Neurogenetic Institute, University of Southern California, Room: 101, 1501 San Pablo Street, Los Angeles, CA 90089 USA
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Sagare AP, Bell RD, Zlokovic BV. Neurovascular defects and faulty amyloid-β vascular clearance in Alzheimer's disease. J Alzheimers Dis 2013; 33 Suppl 1:S87-100. [PMID: 22751174 PMCID: PMC4416477 DOI: 10.3233/jad-2012-129037] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The evidence that neurovascular dysfunction is an integral part of Alzheimer's disease (AD) pathogenesis has continued to emerge in the last decade. Changes in the brain vasculature have been shown to contribute to the onset and progression of the pathological processes associated with AD, such as microvascular reductions, blood brain barrier (BBB) breakdown, and faulty clearance of amyloid β-peptide (Aβ) from the brain. Herein, we review the role of the neurovascular unit and molecular mechanisms in cerebral vascular cells behind the pathogenesis of AD. In particular, we focus on molecular pathways within cerebral vascular cells and the systemic circulation that contribute to BBB dysfunction, brain hypoperfusion, and impaired clearance of Aβ from the brain. We aim to provide a summary of recent research findings implicated in neurovascular defects and faulty Aβ vascular clearance contributing to AD pathogenesis.
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Affiliation(s)
- Abhay P. Sagare
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Robert D. Bell
- Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Berislav V. Zlokovic
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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30
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Sengillo JD, Winkler EA, Walker CT, Sullivan JS, Johnson M, Zlokovic BV. Deficiency in mural vascular cells coincides with blood-brain barrier disruption in Alzheimer's disease. Brain Pathol 2012; 23:303-10. [PMID: 23126372 DOI: 10.1111/bpa.12004] [Citation(s) in RCA: 382] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Accepted: 10/30/2012] [Indexed: 12/13/2022] Open
Abstract
Neurovascular dysfunction contributes to Alzheimer's disease (AD). Cerebrovascular abnormalities and blood-brain barrier (BBB) damage have been shown in AD. The BBB dysfunction can lead to leakage of potentially neurotoxic plasma components in brain that may contribute to neuronal injury. Pericytes are integral in maintaining the BBB integrity. Pericyte-deficient mice develop a chronic BBB damage preceding neuronal injury. Moreover, loss of pericytes was associated with BBB breakdown in patients with amyotrophic lateral sclerosis. Here, we demonstrate a decrease in mural vascular cells in AD, and show that pericyte number and coverage in the cortex and hippocampus of AD subjects compared with neurologically intact controls are reduced by 59% and 60% (P < 0.01), and 32% and 33% (P < 0.01), respectively. An increase in extravascular immunoglobulin G (IgG) and fibrin deposition correlated with reductions in pericyte coverage in AD cases compared with controls; the Pearson's correlation coefficient r for the magnitude of BBB breakdown to IgG and fibrin vs. reduction in pericyte coverage was -0.96 (P < 0.01) and -0.81 (P < 0.01) in the cortex, respectively, and -0.86 (P < 0.01) and -0.98 (P < 0.01) in the hippocampus, respectively. Thus, deficiency in mural vascular cells may contribute to disrupted vascular barrier properties and resultant neuronal dysfunction during AD pathogenesis.
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Affiliation(s)
- Jesse D Sengillo
- Center for Neurodegeneration and Regeneration, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA, USA
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31
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Abstract
The blood-spinal cord barrier (BSCB) regulates molecular exchange between blood and spinal cord. Pericytes are presumed to be important cellular constituents of the BSCB. However, the regional abundance and vascular functions of spinal cord pericytes have yet to be determined. Utilizing wild-type mice, we show that spinal cord pericyte capillary coverage and number compared with the brain regions are reduced most prominently in the anterior horn. Regional pericyte variations are highly correlated with: (1) increased capillary permeability to 350 Da, 40,000 Da, and 150,000 Da, but not 2,000,000 Da fluorescent vascular tracers in cervical, thoracic, and lumbar regions and (2) diminished endothelial zonula occludens-1 (ZO-1) and occludin tight junction protein expression. Pericyte-deficient mutations (Pdgfrβ(F7/F7) mice) resulted in additional pericyte reductions in spinal cord capillaries leading to overt BSCB disruption to serum proteins, accumulation in motor neurons of cyotoxic thrombin and fibrin and motor neuron loss. Barrier disruption in perciyte-deficient mice coincided with further reductions in ZO-1 and occludin. These data suggest that pericytes contribute to proper function of the BSCB at the capillary level. Regional reductions in spinal cord pericytes may provide a cellular basis for heightened spinal cord barrier capillary permeability and motor neuron loss.
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32
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Sagare AP, Deane R, Zlokovic BV. Low-density lipoprotein receptor-related protein 1: a physiological Aβ homeostatic mechanism with multiple therapeutic opportunities. Pharmacol Ther 2012; 136:94-105. [PMID: 22820095 PMCID: PMC3432694 DOI: 10.1016/j.pharmthera.2012.07.008] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 07/03/2012] [Indexed: 11/29/2022]
Abstract
Low-density lipoprotein receptor-related protein-1 (LRP1) is the main cell surface receptor involved in brain and systemic clearance of the Alzheimer's disease (AD) toxin amyloid-beta (Aβ). In plasma, a soluble form of LRP1 (sLRP1) is the major transport protein for peripheral Aβ. LRP1 in brain endothelium and mural cells mediates Aβ efflux from brain by providing a transport mechanism for Aβ across the blood-brain barrier (BBB). sLRP1 maintains a plasma 'sink' activity for Aβ through binding of peripheral Aβ which in turn inhibits re-entry of free plasma Aβ into the brain. LRP1 in the liver mediates systemic clearance of Aβ. In AD, LRP1 expression at the BBB is reduced and Aβ binding to circulating sLRP1 is compromised by oxidation. Cell surface LRP1 and circulating sLRP1 represent druggable targets which can be therapeutically modified to restore the physiological mechanisms of brain Aβ homeostasis. In this review, we discuss how increasing LRP1 expression at the BBB and liver with lifestyle changes, statins, plant-based active principles and/or gene therapy on one hand, and how replacing dysfunctional plasma sLRP1 on the other regulate Aβ clearance from brain ultimately controlling the onset and/or progression of AD.
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Affiliation(s)
- Abhay P. Sagare
- Department of Physiology and Biophysics, and Center for Neurodegeneration and Regeneration at the Zilkha Neurogenetic Institute, University of Southern California, Keck School of Medicine, 1501 San Pablo Street, Los Angeles, CA 90089, United States
| | - Rashid Deane
- Department of Neurosurgery, Arthur Kornberg Medical Research Building, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, United States
| | - Berislav V. Zlokovic
- Department of Physiology and Biophysics, and Center for Neurodegeneration and Regeneration at the Zilkha Neurogenetic Institute, University of Southern California, Keck School of Medicine, 1501 San Pablo Street, Los Angeles, CA 90089, United States
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33
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Vascular factors and epigenetic modifications in the pathogenesis of Alzheimer's disease. J Neurol Sci 2012; 323:25-32. [PMID: 23026534 DOI: 10.1016/j.jns.2012.09.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 09/04/2012] [Accepted: 09/10/2012] [Indexed: 01/08/2023]
Abstract
Alzheimer's disease (AD) is a debilitating illness with no known cure. Nowadays accumulating evidence suggested that the vascular endothelium and chronic hypoperfusion may play important role in pathobiology of AD. The vascular endothelium which regulates the passage of macromolecules and circulating cells from blood to tissue, is a major target of oxidative stress, playing a critical role in the pathophysiology of vascular diseases. Since the vascular endothelium, neurons and glia are all able to synthesize, store and release reactive oxygen species (ROS) and vascular active substances in response to certain stimuli, their contribution to the pathophysiology of AD can be very important. New evidence indicates that continuous formation of free ROS induces cellular damage and decreases antioxidant defenses. Specifically, oxidative stress increases vascular endothelial permeability and promotes leukocyte adhesion. We summarize the reports that sporadic, late-onset of AD results from vascular etiology. Recently an involvement of epigenetic alterations in the etiology of AD is also intensively investigated. Gaining a more complete understanding of the essential components and underlying mechanisms involved in epigenetic regulation could lead to novel treatments for a number of neurological and psychiatric conditions.
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34
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Baloyannis SJ, Baloyannis IS. The vascular factor in Alzheimer's disease: a study in Golgi technique and electron microscopy. J Neurol Sci 2012; 322:117-21. [PMID: 22857991 DOI: 10.1016/j.jns.2012.07.010] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 06/19/2012] [Accepted: 07/05/2012] [Indexed: 12/31/2022]
Abstract
Although the etiopathological background of Alzheimer's disease (AD) is mostly associated with the deposition of Αβ-peptide, the hyperphosphorylation of τ protein, the synaptic pathology and the mitochondrial alterations, the vascular factor may play substantial role in plotting the multifactorial pattern of the disease. We attempted to study the blood capillaries in the hippocampus, the acoustic, the visual and the parietal cortex in twelve early cases of Alzheimer's disease. Samples were processed for Golgi silver impregnation technique and electron microscopy. The morphological findings were compared with normal controls. The study of the brain capillaries in cases of AD, revealed numerous fusiform dilatations, tortuosities, abnormal branching and fusion, though the morphometric estimation revealed a decrease of the number of capillaries per mm(3) in comparison with normal control brains. The ultrastructural study revealed mitochondrial abnormalities in the endothelial cells of a substantial number of capillaries and marked degeneration of the pericytes. Perivascular microglial proliferation was also prominent in the hippocampus and the parietal lobe. Our findings both in Golgi staining and electron microscopy plead in favor of the essential role that the microvascular alterations may play in the broad pathogenetic spectrum of AD.
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35
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Ehrlich D, Humpel C. Chronic vascular risk factors (cholesterol, homocysteine, ethanol) impair spatial memory, decline cholinergic neurons and induce blood-brain barrier leakage in rats in vivo. J Neurol Sci 2012; 322:92-5. [PMID: 22819352 PMCID: PMC3484398 DOI: 10.1016/j.jns.2012.07.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 06/22/2012] [Accepted: 07/02/2012] [Indexed: 11/08/2022]
Abstract
Epidemiological studies show that vascular risk factors (e.g. atherosclerosis, diabetes, homocysteine, hypertension or cholesterol) may play a role in the development of Alzheimer's disease. Animal models may help to discover the role of vascular risk factors on cognition. In the present project we treated male Sprague Dawley rats with a diet containing homocysteine (hyperhomocysteinemia) or cholesterol (hypercholesterolemia) for 5 months or exposed the rats to ethanol (20% in drinking water) or a combination of cholesterol + ethanol (mix) for 12 months. Our experiments show that all 3 treatments (homocysteine, cholesterol, ethanol) declined spatial memory in the 8-arm radial maze, reduced the number of cholinergic neurons and induced blood–brain barrier leakage in the cortex. Rats treated with cholesterol also displayed markedly enhanced inflammation in the cortex. Levels of amyloid precursor protein, beta-amyloid(1–42), as well as tau and phospho-tau 181 were significantly enhanced in the cortex of cholesterol-fed rats. A combination of ethanol and cholesterol did not further potentiate the effects on spatial memory, cholinergic neurons and blood–brain barrier leakage. The data suggest that chronic mild vascular risk factors over months induce small lesions of the brain capillaries in the cortex, which may contribute to the development of vascular dementia or also Alzheimer's disease.
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Affiliation(s)
- Daniela Ehrlich
- Laboratory for Psychiatry and Exp. Alzheimer's Research, Department of Psychiatry and Psychotherapy, Anichstr. 35, 6020 Innsbruck, Austria
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36
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Deane R, Singh I, Sagare AP, Bell RD, Ross NT, LaRue B, Love R, Perry S, Paquette N, Deane RJ, Thiyagarajan M, Zarcone T, Fritz G, Friedman AE, Miller BL, Zlokovic BV. A multimodal RAGE-specific inhibitor reduces amyloid β-mediated brain disorder in a mouse model of Alzheimer disease. J Clin Invest 2012; 122:1377-92. [PMID: 22406537 DOI: 10.1172/jci58642] [Citation(s) in RCA: 464] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Accepted: 02/06/2012] [Indexed: 01/11/2023] Open
Abstract
In Alzheimer disease (AD), amyloid β peptide (Aβ) accumulates in plaques in the brain. Receptor for advanced glycation end products (RAGE) mediates Aβ-induced perturbations in cerebral vessels, neurons, and microglia in AD. Here, we identified a high-affinity RAGE-specific inhibitor (FPS-ZM1) that blocked Aβ binding to the V domain of RAGE and inhibited Aβ40- and Aβ42-induced cellular stress in RAGE-expressing cells in vitro and in the mouse brain in vivo. FPS-ZM1 was nontoxic to mice and readily crossed the blood-brain barrier (BBB). In aged APPsw/0 mice overexpressing human Aβ-precursor protein, a transgenic mouse model of AD with established Aβ pathology, FPS-ZM1 inhibited RAGE-mediated influx of circulating Aβ40 and Aβ42 into the brain. In brain, FPS-ZM1 bound exclusively to RAGE, which inhibited β-secretase activity and Aβ production and suppressed microglia activation and the neuroinflammatory response. Blockade of RAGE actions at the BBB and in the brain reduced Aβ40 and Aβ42 levels in brain markedly and normalized cognitive performance and cerebral blood flow responses in aged APPsw/0 mice. Our data suggest that FPS-ZM1 is a potent multimodal RAGE blocker that effectively controls progression of Aβ-mediated brain disorder and that it may have the potential to be a disease-modifying agent for AD.
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Affiliation(s)
- Rashid Deane
- Center of Neurodegenerative and Vascular Brain Disorders, University of Rochester, Rochester, New York, USA
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37
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Progressive neurovascular disturbances in the cerebral cortex of Alzheimer's disease-model mice: protection by atorvastatin and pitavastatin. Neuroscience 2011; 197:358-68. [PMID: 21955601 DOI: 10.1016/j.neuroscience.2011.09.030] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 09/08/2011] [Accepted: 09/14/2011] [Indexed: 11/22/2022]
Abstract
Structural and functional abnormalities in the neurovascular unit (NVU) have been recently observed in Alzheimer's disease (AD). Statins, which are used clinically for reducing cholesterol levels, can also exert beneficial vascular actions. Thus, we examined the protective effects of statins on NVU disturbances in a mouse AD model. Amyloid precursor protein (APP) transgenic (Tg) mice were used as a model of AD. Atorvastatin (30 mg/kg/day, p.o.) or pitavastatin (3 mg/kg/day, p.o.) were administered from 5 to 20 months of age. Changes in the NVU, including the endothelium and basement membrane, as well as astrogliosis and matrix metalloproteinase-9 (MMP-9) activation, were assessed. There was a reduction in immunopositive staining for N-acetyl glucosamine oligomer (NAGO) in the endothelium and in collagen IV in the APP vehicle (APP/Ve) group, with collagen IV staining most weakest near senile plaques (SPs). There was also an increase in intensity and number of glial fibrillary acidic protein (GFAP)-positive astrocytes, particularly around the SP, where MMP-9 was more strongly labeled. Double immunofluorescent analysis showed that astrocytic endfeet had detached from the capillary endothelium in the APP/Ve group. Treatment with atorvastatin or pitavastatin ameliorated the activation of MMP-9. Overall, these data suggest that statins may have therapeutic potential for AD by protecting NVU.
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38
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Lagaraine C, Skipor J, Szczepkowska A, Dufourny L, Thiery JC. Tight junction proteins vary in the choroid plexus of ewes according to photoperiod. Brain Res 2011; 1393:44-51. [PMID: 21529785 DOI: 10.1016/j.brainres.2011.04.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Revised: 03/07/2011] [Accepted: 04/02/2011] [Indexed: 10/18/2022]
Abstract
Sheep from temperate latitudes exhibit seasonal variations in many physiological functions such as reproduction, food intake, body weight, and pelage growth. Majority of seasonal changes are controlled by the annual photoperiodic cycle and melatonin secretion. For reproduction, the resulting key event is a modulation of the negative feedback of steroids on gonadotropin secretion. However, this seasonal effect could also depend on variable uptake of steroids by the brain. Seasonal regulation of food intake also involves numerous peripheral hormones, among which the protein hormone leptin informs the brain on the metabolic status of the animal. It has been shown previously that access of progesterone, estradiol and leptin to the cerebrospinal fluid (CSF) increases under long days. This physiological modulation of the passage of hormones to the brain could depend on regulation of the permeability of the blood-CSF barrier. This study therefore compared the tight junction proteins in the choroid plexus of ewes exposed to short days or long days. Levels of occludin, zonula occludens proteins (ZO) ZO-1 and ZO-2, afadin and cadherin were significantly higher during short days, but no statistical difference was observed for junctional adhesion molecule 1 (JAM-1), ZO-3 or claudins 1 and 5. These results are consistent with an increase in the blood-CSF barrier permeability during long days through a regulation of tight junctions and show that the permeability could depend upon physiological conditions such as photoperiodic status.
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Affiliation(s)
- Christine Lagaraine
- INRA, UMR85 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France
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39
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Paris D, Bachmeier C, Patel N, Quadros A, Volmar CH, Laporte V, Ganey J, Beaulieu-Abdelahad D, Ait-Ghezala G, Crawford F, Mullan MJ. Selective antihypertensive dihydropyridines lower Aβ accumulation by targeting both the production and the clearance of Aβ across the blood-brain barrier. Mol Med 2011; 17:149-62. [PMID: 21170472 PMCID: PMC3060987 DOI: 10.2119/molmed.2010.00180] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Accepted: 12/16/2010] [Indexed: 11/06/2022] Open
Abstract
Several large population-based or clinical trial studies have suggested that certain dihydropyridine (DHP) L-type calcium channel blockers (CCBs) used for the treatment of hypertension may confer protection against the development of Alzheimer disease (AD). However, other studies with drugs of the same class have shown no beneficial clinical effects. To determine whether certain DHPs are able to impact underlying disease processes in AD (specifically the accumulation of the Alzheimer Aβ peptide), we investigated the effect of several antihypertensive DHPs and non-DHP CCBs on Aβ production. Among the antihypertensive DHPs tested, a few, including nilvadipine, nitrendipine and amlodipine inhibited Aβ production in vitro, whereas others had no effect or raised Aβ levels. In vivo, nilvadipine and nitrendipine acutely reduced brain Aβ levels in a transgenic mouse model of AD (Tg PS1/APPsw) and improved Aβ clearance across the blood-brain barrier (BBB), whereas amlodipine and nifedipine were ineffective showing that the Aβ-lowering activity of the DHPs is independent of their antihypertensive activity. Chronic oral treatment with nilvadipine decreased Aβ burden in the brains of Tg APPsw (Tg2576) and Tg PS1/APPsw mice, and also improved learning abilities and spatial memory. Our data suggest that the clinical benefit conferred by certain antihypertensive DHPs against AD is unrelated to their antihypertensive activity, but rely on their ability to lower brain Aβ accumulation by affecting both Aβ production and Aβ clearance across the BBB.
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Affiliation(s)
- Daniel Paris
- The Roskamp Institute, Sarasota, Florida 34243, United States of America.
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40
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Sagare AP, Deane R, Zetterberg H, Wallin A, Blennow K, Zlokovic BV. Impaired lipoprotein receptor-mediated peripheral binding of plasma amyloid-β is an early biomarker for mild cognitive impairment preceding Alzheimer's disease. J Alzheimers Dis 2011; 24:25-34. [PMID: 21157031 PMCID: PMC4096563 DOI: 10.3233/jad-2010-101248] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Soluble circulating low density lipoprotein receptor-related protein-1 (sLRP) provides key plasma binding activity for Alzheimer's disease (AD) amyloid-β peptide (Aβ). sLRP normally binds 70-90% of plasma Aβ preventing free Aβ access to the brain. In AD, Aβ binding to sLRP is compromised by increased levels of oxidized sLRP which does not bind Aβ. Here, we determined plasma oxidized sLRP and Aβ40/42 sLRP-bound, other proteins-bound and free plasma fractions, cerebrospinal fluid (CSF) tau/Aβ42 ratios, and mini-mental state examination (MMSE) scores in patients with mild cognitive impairment (MCI) who progressed to AD (MCI-AD, n = 14), AD (n = 14) and neurologically healthy controls (n = 14) recruited from the Göteborg MCI study. In MCI-AD patients prior to conversion to AD and AD patients, the respective increases in oxidized sLRP and free plasma Aβ40 and Aβ42 levels were 4.9 and 3.7-fold, 1.8, and 1.7-fold and 4.3 and 3.3-fold (p < 0.05, ANOVA with Tuckey post-hoc test). In MCI-AD and AD patients increases in oxidized sLRP and free plasma Aβ40 and Aβ42 correlated with increases in CSF tau/Aβ42 ratios and reductions in MMSE scores (p < 0.05, Pearson analysis). A heterogeneous group of 'stable' MCI patients that was followed over 2-4 years (n = 24) had normal CSF tau/Aβ42 ratios but increased oxidized sLRP levels (p < 0.05, Student's t test). Data suggests that a deficient sLRP-Aβ binding might precede and correlate later in disease with an increase in the tau/Aβ42 CSF ratio and global cognitive decline in MCI individuals converting into AD, and therefore is an early biomarker for AD-type dementia.
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Affiliation(s)
- Abhay P. Sagare
- Center for Neurodegenerative and Vascular Brain Disorders, University of Rochester, Rochester, NY, USA
| | - Rashid Deane
- Center for Neurodegenerative and Vascular Brain Disorders, University of Rochester, Rochester, NY, USA
| | - Henrik Zetterberg
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, The Sahlgrenska Academy at University of Gothenburg, Mölndal, Sweden
| | - Anders Wallin
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, The Sahlgrenska Academy at University of Gothenburg, Mölndal, Sweden
| | - Kaj Blennow
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, The Sahlgrenska Academy at University of Gothenburg, Mölndal, Sweden
| | - Berislav V. Zlokovic
- Center for Neurodegenerative and Vascular Brain Disorders, University of Rochester, Rochester, NY, USA
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41
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Zlokovic BV, Deane R, Sagare AP, Bell RD, Winkler EA. Low-density lipoprotein receptor-related protein-1: a serial clearance homeostatic mechanism controlling Alzheimer's amyloid β-peptide elimination from the brain. J Neurochem 2010; 115:1077-89. [PMID: 20854368 PMCID: PMC2972355 DOI: 10.1111/j.1471-4159.2010.07002.x] [Citation(s) in RCA: 200] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Low-density lipoprotein receptor-related protein-1 (LRP1), a member of the low-density lipoprotein receptor family, has major roles in the cellular transport of cholesterol, endocytosis of 40 structurally diverse ligands, transcytosis of ligands across the blood-brain barrier, and transmembrane and nuclear signaling. Recent evidence indicates that LRP1 regulates brain and systemic clearance of Alzheimer's disease (AD) amyloid β-peptide (Aβ). According to the two-hit vascular hypothesis for AD, vascular damage precedes cerebrovascular and brain Aβ accumulation (hit 1) which then further amplifies neurovascular dysfunction (hit 2) preceding neurodegeneration. In this study, we discuss the roles of LRP1 during the hit 1 and hit 2 stage of AD pathogenesis and describe a three-level serial LRP1-dependent homeostatic control of Aβ clearance including (i) cell-surface LRP1 at the blood-brain barrier and cerebrovascular cells mediating brain-to-blood Aβ clearance (ii) circulating LRP1 providing a key endogenous peripheral 'sink' activity for plasma Aβ which prevents free Aβ access to the brain, and (iii) LRP1 in the liver mediating systemic Aβ clearance. Pitfalls in experimental Aβ brain clearance measurements with the concurrent use of peptides/proteins such as receptor-associated protein and aprotinin are also discussed. We suggest that LRP1 has a critical role in AD pathogenesis and is an important therapeutic target in AD.
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Affiliation(s)
- Berislav V Zlokovic
- Center for Neurodegenerative and Vascular Brain Disorders, University of Rochester Medical Center, Rochester, New York 14642,, USA.
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42
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Trueblood NA, Ramasamy R, Wang LF, Schaefer S. Niacin protects the isolated heart from ischemia-reperfusion injury. Am J Physiol Heart Circ Physiol 2000; 279:H764-71. [PMID: 10924076 DOI: 10.1152/ajpheart.2000.279.2.h764] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nicotinic acid (niacin) has been shown to decrease myocyte injury. Because interventions that lower the cytosolic NADH/NAD(+) ratio improve glycolysis and limit infarct size, we hypothesized that 1) niacin, as a precursor of NAD(+), would lower the NADH/NAD(+) ratio, increase glycolysis, and limit ischemic injury and 2) these cardioprotective benefits of niacin would be limited in conditions that block lactate removal. Isolated rat hearts were perfused without (Ctl) or with 1 microM niacin (Nia) and subjected to 30 min of low-flow ischemia (10% of baseline flow, LF) and reperfusion. To examine the effects of limiting lactate efflux, experiments were performed with 1) Ctl and Nia groups subjected to zero-flow ischemia and 2) the Nia group treated with the lactate-H(+) cotransport inhibitor alpha-cyano-4-hydroxycinnamate under LF conditions. Measured variables included ATP, pH, cardiac function, tissue lactate-to-pyruvate ratio (reflecting NADH/NAD(+)), lactate efflux rate, and creatine kinase release. The lactate-to-pyruvate ratio was reduced by more than twofold in Nia-LF hearts during baseline and ischemic conditions (P < 0.001 and P < 0.01, respectively), with concurrent lower creatine kinase release than Ctl hearts (P < 0.05). Nia-LF hearts had significantly greater lactate release during ischemia (P < 0.05 vs. Ctl hearts) as well as higher functional recovery and a relative preservation of high-energy phosphates. Inhibiting lactate efflux with alpha-cyano-4-hydroxycinnamate and blocking lactate washout with zero flow negated some of the beneficial effects of niacin. During LF, niacin lowered the cytosolic redox state and increased lactate efflux, consistent with redox regulation of glycolysis. Niacin significantly improved functional and metabolic parameters under these conditions, providing additional rationale for use of niacin as a therapeutic agent in patients with ischemic heart disease.
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Affiliation(s)
- N A Trueblood
- Division of Cardiovascular Medicine, Department of Medicine, University of California, Davis, California 95616, USA
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Pellerin L, Pellegri G, Martin JL, Magistretti PJ. Expression of monocarboxylate transporter mRNAs in mouse brain: support for a distinct role of lactate as an energy substrate for the neonatal vs. adult brain. Proc Natl Acad Sci U S A 1998; 95:3990-5. [PMID: 9520480 PMCID: PMC19950 DOI: 10.1073/pnas.95.7.3990] [Citation(s) in RCA: 237] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Under particular circumstances like lactation and fasting, the blood-borne monocarboxylates acetoacetate, beta-hydroxybutyrate, and lactate represent significant energy substrates for the brain. Their utilization is dependent on a transport system present on both endothelial cells forming the blood-brain barrier and on intraparenchymal brain cells. Recently, two monocarboxylate transporters, MCT1 and MCT2, have been cloned. We report here the characterization by Northern blot analysis and by in situ hybridization of the expression of MCT1 and MCT2 mRNAs in the mouse brain. In adults, both transporter mRNAs are highly expressed in the cortex, the hippocampus and the cerebellum. During development, a peak in the expression of both transporters occurs around postnatal day 15, declining rapidly by 30 days at levels observed in adults. Double-labeling experiments reveal that the expression of MCT1 mRNA in endothelial cells is highest at postnatal day 15 and is not detectable at adult stages. These results support the notion that monocarboxylates are important energy substrates for the brain at early postnatal stages and are consistent with the sharp decrease in blood-borne monocarboxylate utilization after weaning. In addition, the observation of a sustained intraparenchymal expression of monocarboxylate transporter mRNAs in adults, in face of the seemingly complete disappearance of their expression on endothelial cells, reinforces the view that an intercellular exchange of lactate occurs within the adult brain.
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Affiliation(s)
- L Pellerin
- Institut de Physiologie et Laboratoire de Recherche du Service de Neurologie du Centre Hospitalier Universitaire Vaudois, Faculté de Médecine, Université de Lausanne, 7 rue du Bugnon, 1005 Lausanne, Switzerland.
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Baker SK, McCullagh KJ, Bonen A. Training intensity-dependent and tissue-specific increases in lactate uptake and MCT-1 in heart and muscle. J Appl Physiol (1985) 1998; 84:987-94. [PMID: 9480961 DOI: 10.1152/jappl.1998.84.3.987] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We investigated the effects of 3 wk of moderate- (21 m/min, 8% grade) and highintensity treadmill training (31 m/min, 15% grade) on 1) monocarboxylate transporter 1 (MCT-1) content in rat hindlimb muscles and the heart and 2) lactate uptake in isolated soleus (Sol) muscles and perfused hearts. In the moderately trained group MCT-1 was not increased in any of the muscles [Sol, extensor digitorum longus (EDL), and red (RG) and white gastrocnemius (WG)] (P > 0.05). Similarly, lactate uptake in Sol strips was also not increased (P > 0.05). In contrast, in the heart, MCT-1 (+36%, P < 0.05) and lactate uptake (+72%, P < 0.05) were increased with moderate training. In the highly trained group, MCT-1 (+70%, P < 0.05) and lactate uptake (+79%, P < 0.05) were increased in Sol. MCT-1 was also increased in RG (+94%, P < 0.05) but not in WG and EDL (P > 0.05). In the highly trained group, heart MCT-1 (+44%, P < 0.05) and lactate uptake (+173%, P < 0.05) were increased. In conclusion, it has been shown that 1) in both heart and skeletal muscle lactate uptake is increased only when MCT-1 is increased; 2) training-induced increases in MCT-1 occurred at a lower training intensity in the heart than in skeletal muscle; 3) in the heart, lactate uptake was increased much more after high-intensity training than after moderate-intensity training, despite similar increases in heart MCT-1 with these two training intensities; and 4) the increases in MCT-1 occurred independently of any changes in the heart's oxidative capacity (as measured by citrate synthase activity).
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Affiliation(s)
- S K Baker
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
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Abstract
In this article, the importance of lactic acid transport into and out of heart cells is described and the properties of the monocarboxylate transporters (MCTs) responsible are presented. These are monocarboxylate/proton symporters with a broad substrate specificity that includes L-lactate, pyruvate, and the ketone bodies acetate, acetoacetate, and beta-hydroxybutyrate. Although it is unlikely that lactic acid transport constrains heart metabolism under most conditions, it may do so during severe hypoxia or ischemia. The transporter plays a critical role in maintaining intracellular pH because it removes the protons that are produced stoichiometrically with lactate during glycolysis. The kinetics and substrate and inhibitor specificities of the transport process have been determined in cell suspensions using a radiotracer technique and in single cells using a fluorescent measurement of the decrease in intracellular pH that accompanies transport. The results of these experiments suggest the presence of 2 different transporter isoforms in heart cells, at least one of which is different from the cloned MCT1 and MCT2. Immunofluorescence microscopy shows that MCT1 expression is restricted to the intercalated disk region, yet the rate of lactate transport in this region is slower than in the center of the cell, where there is no MCT1. New cDNA sequences with strong homology to MCT1 have been found in human cDNA libraries and Northern blots show that the corresponding mRNA is expressed in rat heart. Expressions of these new MCT isoforms have yet to be demonstrated and their properties and cellular distribution defined.
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Affiliation(s)
- A P Halestrap
- Department of Biochemistry, School of Medical Sciences, University of Bristol, U.K
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Mitrović DM, Redzić ZB, Marković ID, Jovanović SS, Rosić MA, Rakić LM. Tiazofurine uptake by the isolated guinea pig heart. J Chemother 1995; 7:543-8. [PMID: 8667040 DOI: 10.1179/joc.1995.7.6.543] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Tiazofurine is a selective inhibitor of the enzyme inosine monophosphate dehydrogenase, and exhibits potent antitumor activity. Considering the potential side effects on the heart, [3H] tiazofurine uptake into the cardiomyocytes, as well as the mechanism of transport, were studied in the isolated perfused guinea pig heart, using the rapid single circulation, paired-tracer technique. The maximal cellular uptake (Umax) of [3H] tiazofurine ranged from 19% to 25% of the injected dose, with total cellular uptake (Utot) ranging 12.1-15.6%. The addition of unlabeled tiazofurine caused inhibition of [3H] tiazofurine uptake, with a Umax value of 9.06 +/- 4.6%. Therefore, the uptake of tiazofurine into cardiomyocytes could be considered a saturable process. The inhibition of [3H] tiazofurine uptake caused by adenosine and dipyridamole was of the same degree as the inhibition by unlabeled tiazofurine. Thus, it can be assumed that nucleosides' transport system(s) are involved in transport of tiazofurine into myocardial cells.
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Affiliation(s)
- D M Mitrović
- Department of Physiology, School of Medicine, Belgrade University, Yugoslavia
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McCullagh KJ, Bonen A. L(+)-lactate binding to a protein in rat skeletal muscle plasma membranes. CANADIAN JOURNAL OF APPLIED PHYSIOLOGY = REVUE CANADIENNE DE PHYSIOLOGIE APPLIQUEE 1995; 20:112-24. [PMID: 7742767 DOI: 10.1139/h95-009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Biochemical studies were conducted to determine the location of a putative lactate transport protein in rat skeletal muscle plasma membranes (PM). PM (50-100 micrograms protein) were incubated with [U-14C] L(+)-lactate, in the presence or absence of unlabeled monocarboxylates or potential inhibitors, after which proteins were separated by SDS-PAGE. Gel slices (2 mm) were cut and analyzed for 14C. [U-14C] L(+)-lactate was bound to plasma membranes in the 30 to 40 kDa molecular mass range. Binding of [U-14C] L(+)-lactate was inhibited by N-ethylmaleimide, unlabeled L-lactate and pyruvate, and in a dose dependent manner by alpha-cyano-4-hydroxycinnamate (r = 0.995), but not by cytochalasin-B. The inhibition of [U-14C] L(+)-lactate binding was similar to the inhibition of lactate transport. Therefore the transport of L(+)-lactate across skeletal muscle plasma membranes involves a polypeptide of 30 to 40 kDa.
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Affiliation(s)
- K J McCullagh
- Department of Kinesiology, University of Waterloo, Ontario
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Allen PJ, Brooks GA. Partial purification and reconstitution of the sarcolemmal L-lactate carrier from rat skeletal muscle. Biochem J 1994; 303 ( Pt 1):207-12. [PMID: 7945241 PMCID: PMC1137577 DOI: 10.1042/bj3030207] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Purified sarcolemmal membranes from mixed rat hindlimb muscle were solubilized with octylglucoside and the extract subjected to hydroxylapatite (HA) chromatography. Following protein elution with a sodium phosphate gradient and detergent removal by dialysis, the HA eluate was reconstituted into asolectin liposomes using a freeze-thaw procedure. Specific L-[14C]lactate transport activity eluting from the 0.2 M sodium phosphate fraction was 30-fold higher compared with native sarcolemmal vesicles (31.64 versus 1.06 nmol/min per mg). The reconstituted carrier exhibited Michaelis-Menten saturation kinetics with Km and Vmax. values of 46.2 +/- 6.6 mM and 498.7 +/- 17.2 nmol/15 s per mg respectively. L-Lactate transport activity was inhibited 57% by preincubation of proteoliposomes with 10 mM alpha-cyano-4-hydroxycinnamate, a known inhibitor of lactate transport. Analysis of the HA eluates by SDS/PAGE showed the presence of a 34 kDa band corresponding to lactate transport activity. Reconstitution of lactate transport activity eluting from the HA column, together with SDS/PAGE analysis suggests the presence of a 34 kDa polypeptide mediating sarcolemmal lactate exchange in rat skeletal muscle.
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Affiliation(s)
- P J Allen
- Department of Human Biodynamics, University of California, Berkeley 97420
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Taylor DL, Richards DA, Obrenovitch TP, Symon L. Time course of changes in extracellular lactate evoked by transient K(+)-induced depolarisation in the rat striatum. J Neurochem 1994; 62:2368-74. [PMID: 8189242 DOI: 10.1046/j.1471-4159.1994.62062368.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The purpose of this study was to establish whether excessive lactate production associated with local application of K+ is reflected at the extracellular level during or after the K+ challenge. Changes in extracellular lactate were continuously monitored by microdialysis coupled to on-line fluorimetric analysis. K(+)-induced changes in dialysate lactate were closely related to those of the direct current potential. High K+ evoked a large and sustained negative shift of direct current potential onto which were superimposed a variable number of transient peaks of further depolarisation. The initial negative shift in direct current potential was associated with a decrease in dialysate lactate, but after each transient depolarisation, the positive shift in direct current potential indicating cell repolarisation was associated with a marked increase in extracellular lactate. When repetitive transient depolarisations occurred during a stimulus, only a small increase after each depolarisation was observed. However, recordings consistently revealed a marked and rapid increase in extracellular lactate after the K+ stimulus. These data indicate that extracellular lactate mostly increased during periods of repolarisation. This suggests strongly that lactic acid transport out of brain cells may be impaired when their transmembrane ionic gradients are disrupted.
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Affiliation(s)
- D L Taylor
- Gough-Cooper Department of Neurological Surgery, Institute of Neurology, London, England U.K
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Shieh RC, Goldhaber JI, Stuart JS, Weiss JN. Lactate transport in mammalian ventricle. General properties and relation to K+ fluxes. Circ Res 1994; 74:829-38. [PMID: 8156630 DOI: 10.1161/01.res.74.5.829] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Net cellular L-lactate efflux associated with accelerated anaerobic glycolysis has been implicated as a potential cause of the marked cellular K+ loss contributing to lethal cardiac arrhythmias in ischemic heart and to impaired function of fatigued skeletal muscle. To examine the mechanisms of transsarcolemmal L-lactate movement in the heart, isolated guinea pig ventricular myocytes were loaded with the fluorescent H+ or K+ indicators, carboxy SNARF-1 or PBFI, respectively, under whole-cell patch-clamp conditions. With H+ as the only permeable monovalent cation, a rapid increase in extracellular L-lactate concentration ([L-]o) from 0 to 30 mmol/L at constant pHo (7.35) caused an intracellular acidification averaging 0.18 +/- 0.02 pH units in 60 seconds (n = 7), reflecting L-lactate influx in association with H+ influx (or OH- efflux). Under voltage-clamp conditions, no significant electrogenic current was associated with H(+)-coupled L-lactate influx, and membrane potential (-75 to +75 mV) had no effect on the degree of acidification produced by 30 mmol/L [L-]o, indicating that L-lactate influx was predominantly nonelectrogenic. Acidification in response to increased [L-]o was saturable (Km, approximately 5 mmol/L), partially stereospecific for L-lactate over D-lactate, and inhibited by 55 +/- 7% and 82 +/- 7% by the monocarboxylate carrier inhibitors alpha-cyano-4-hydroxycinnamate and mersalyl acid, respectively, consistent with a carrier-mediated transport mechanism. Extracellular K+ inhibited H(+)-coupled L-lactate influx by 36 +/- 2%, suggesting that K+ either inhibited or substituted for H+ in cotransport with L-lactate. However, in myocytes loaded with PBFI, no significant increase in [K+]i was detected during exposure to 30 mmol/L [L-]o, suggesting that only a minor component, if any, of L-lactate influx was cotransported or codiffused with K+.
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Affiliation(s)
- R C Shieh
- Department of Medicine (Cardiology), UCLA School of Medicine 90024
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