1
|
Endothelial Dysfunction in Neurodegenerative Diseases. Int J Mol Sci 2023; 24:ijms24032909. [PMID: 36769234 PMCID: PMC9918222 DOI: 10.3390/ijms24032909] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/16/2023] [Accepted: 01/18/2023] [Indexed: 02/05/2023] Open
Abstract
The cerebral vascular system stringently regulates cerebral blood flow (CBF). The components of the blood-brain barrier (BBB) protect the brain from pathogenic infections and harmful substances, efflux waste, and exchange substances; however, diseases develop in cases of blood vessel injuries and BBB dysregulation. Vascular pathology is concurrent with the mechanisms underlying aging, Alzheimer's disease (AD), and vascular dementia (VaD), which suggests its involvement in these mechanisms. Therefore, in the present study, we reviewed the role of vascular dysfunction in aging and neurodegenerative diseases, particularly AD and VaD. During the development of the aforementioned diseases, changes occur in the cerebral blood vessel morphology and local cells, which, in turn, alter CBF, fluid dynamics, and vascular integrity. Chronic vascular inflammation and blood vessel dysregulation further exacerbate vascular dysfunction. Multitudinous pathogenic processes affect the cerebrovascular system, whose dysfunction causes cognitive impairment. Knowledge regarding the pathophysiology of vascular dysfunction in neurodegenerative diseases and the underlying molecular mechanisms may lead to the discovery of clinically relevant vascular biomarkers, which may facilitate vascular imaging for disease prevention and treatment.
Collapse
|
2
|
Morofuji Y, Nakagawa S. Drug Development for Central Nervous System Diseases Using In vitro Blood-brain Barrier Models and Drug Repositioning. Curr Pharm Des 2020; 26:1466-1485. [PMID: 32091330 PMCID: PMC7499354 DOI: 10.2174/1381612826666200224112534] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/30/2020] [Indexed: 12/15/2022]
Abstract
An important goal of biomedical research is to translate basic research findings into practical clinical implementation. Despite the advances in the technology used in drug discovery, the development of drugs for central nervous system diseases remains challenging. The failure rate for new drugs targeting important central nervous system diseases is high compared to most other areas of drug discovery. The main reason for the failure is the poor penetration efficacy across the blood-brain barrier. The blood-brain barrier represents the bottleneck in central nervous system drug development and is the most important factor limiting the future growth of neurotherapeutics. Meanwhile, drug repositioning has been becoming increasingly popular and it seems a promising field in central nervous system drug development. In vitro blood-brain barrier models with high predictability are expected for drug development and drug repositioning. In this review, the recent progress of in vitro BBB models and the drug repositioning for central nervous system diseases will be discussed.
Collapse
Affiliation(s)
- Yoichi Morofuji
- Department of Neurosurgery, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8501, Japan
| | - Shinsuke Nakagawa
- Department of Medical Pharmacology, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
| |
Collapse
|
3
|
Salman MM, Marsh G, Kusters I, Delincé M, Di Caprio G, Upadhyayula S, de Nola G, Hunt R, Ohashi KG, Gray T, Shimizu F, Sano Y, Kanda T, Obermeier B, Kirchhausen T. Design and Validation of a Human Brain Endothelial Microvessel-on-a-Chip Open Microfluidic Model Enabling Advanced Optical Imaging. Front Bioeng Biotechnol 2020; 8:573775. [PMID: 33117784 PMCID: PMC7576009 DOI: 10.3389/fbioe.2020.573775] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 08/21/2020] [Indexed: 01/30/2023] Open
Abstract
We describe here the design and implementation of an in vitro microvascular open model system using human brain microvascular endothelial cells. The design has several advantages over other traditional closed microfluidic platforms: (1) it enables controlled unidirectional flow of media at physiological rates to support vascular function, (2) it allows for very small volumes which makes the device ideal for studies involving biotherapeutics, (3) it is amenable for multiple high resolution imaging modalities such as transmission electron microscopy (TEM), 3D live fluorescence imaging using traditional spinning disk confocal microscopy, and advanced lattice light sheet microscopy (LLSM). Importantly, we miniaturized the design, so it can fit within the physical constraints of LLSM, with the objective to study physiology in live cells at subcellular level. We validated barrier function of our brain microvessel-on-a-chip by measuring permeability of fluorescent dextran and a human monoclonal antibody. One potential application is to investigate mechanisms of transcytosis across the brain microvessel-like barrier of fluorescently-tagged biologics, viruses or nanoparticles.
Collapse
Affiliation(s)
- Mootaz M Salman
- Department of Cell Biology, Harvard Medical School, Boston, MA, United States.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, United States
| | | | - Ilja Kusters
- Department of Cell Biology, Harvard Medical School, Boston, MA, United States.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, United States
| | - Matthieu Delincé
- Department of Cell Biology, Harvard Medical School, Boston, MA, United States.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, United States
| | - Giuseppe Di Caprio
- Department of Cell Biology, Harvard Medical School, Boston, MA, United States.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, United States
| | - Srigokul Upadhyayula
- Department of Cell Biology, Harvard Medical School, Boston, MA, United States.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, United States
| | - Giovanni de Nola
- Department of Cell Biology, Harvard Medical School, Boston, MA, United States.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, United States
| | - Ronan Hunt
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, United States
| | - Kazuka G Ohashi
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, United States
| | | | | | - Yasuteru Sano
- Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Takashi Kanda
- Yamaguchi University Graduate School of Medicine, Ube, Japan
| | | | - Tom Kirchhausen
- Department of Cell Biology, Harvard Medical School, Boston, MA, United States.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, United States.,Department of Pediatrics, Harvard Medical School, Boston, MA, United States
| |
Collapse
|
4
|
Wevers NR, Kasi DG, Gray T, Wilschut KJ, Smith B, van Vught R, Shimizu F, Sano Y, Kanda T, Marsh G, Trietsch SJ, Vulto P, Lanz HL, Obermeier B. A perfused human blood-brain barrier on-a-chip for high-throughput assessment of barrier function and antibody transport. Fluids Barriers CNS 2018; 15:23. [PMID: 30165870 PMCID: PMC6117964 DOI: 10.1186/s12987-018-0108-3] [Citation(s) in RCA: 191] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 07/30/2018] [Indexed: 12/13/2022] Open
Abstract
Background Receptor-mediated transcytosis is one of the major routes for drug delivery of large molecules into the brain. The aim of this study was to develop a novel model of the human blood–brain barrier (BBB) in a high-throughput microfluidic device. This model can be used to assess passage of large biopharmaceuticals, such as therapeutic antibodies, across the BBB. Methods The model comprises human cell lines of brain endothelial cells, astrocytes, and pericytes in a two-lane or three-lane microfluidic platform that harbors 96 or 40 chips, respectively, in a 384-well plate format. In each chip, a perfused vessel of brain endothelial cells was grown against an extracellular matrix gel, which was patterned by means of surface tension techniques. Astrocytes and pericytes were added on the other side of the gel to complete the BBB on-a-chip model. Barrier function of the model was studied using fluorescent barrier integrity assays. To test antibody transcytosis, the lumen of the model’s endothelial vessel was perfused with an anti-transferrin receptor antibody or with a control antibody. The levels of antibody that penetrated to the basal compartment were quantified using a mesoscale discovery assay. Results The perfused BBB on-a-chip model shows presence of adherens and tight junctions and severely limits the passage of a 20 kDa FITC-dextran dye. Penetration of the antibody targeting the human transferrin receptor (MEM-189) was markedly higher than penetration of the control antibody (apparent permeability of 2.9 × 10−5 versus 1.6 × 10−5 cm/min, respectively). Conclusions We demonstrate successful integration of a human BBB microfluidic model in a high-throughput plate-based format that can be used for drug screening purposes. This in vitro model shows sufficient barrier function to study the passage of large molecules and is sensitive to differences in antibody penetration, which could support discovery and engineering of BBB-shuttle technologies. Electronic supplementary material The online version of this article (10.1186/s12987-018-0108-3) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Nienke R Wevers
- Mimetas BV, J.H. Oortweg 19, 2333 CH, Leiden, The Netherlands. .,Department of Cell and Chemical Biology, Leiden University Medical Centre, Einthovenweg 20, 2333 ZC, Leiden, The Netherlands.
| | - Dhanesh G Kasi
- Mimetas BV, J.H. Oortweg 19, 2333 CH, Leiden, The Netherlands
| | - Taylor Gray
- Biogen, 225 Binney Street, Cambridge, MA, 02142, USA
| | | | | | - Remko van Vught
- Mimetas BV, J.H. Oortweg 19, 2333 CH, Leiden, The Netherlands
| | - Fumitaka Shimizu
- Yamaguchi University Graduate School of Medicine, Minamikogushi, Ube, Yamaguchi, 7558505, Japan
| | - Yasuteru Sano
- Yamaguchi University Graduate School of Medicine, Minamikogushi, Ube, Yamaguchi, 7558505, Japan
| | - Takashi Kanda
- Yamaguchi University Graduate School of Medicine, Minamikogushi, Ube, Yamaguchi, 7558505, Japan
| | - Graham Marsh
- Biogen, 225 Binney Street, Cambridge, MA, 02142, USA
| | | | - Paul Vulto
- Mimetas BV, J.H. Oortweg 19, 2333 CH, Leiden, The Netherlands
| | | | | |
Collapse
|
5
|
Prabhakarpandian B, Shen MC, Nichols JB, Mills IR, Sidoryk-Wegrzynowicz M, Aschner M, Pant K. SyM-BBB: a microfluidic Blood Brain Barrier model. LAB ON A CHIP 2013; 13:1093-101. [PMID: 23344641 PMCID: PMC3613157 DOI: 10.1039/c2lc41208j] [Citation(s) in RCA: 197] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Current techniques for mimicking the Blood-Brain Barrier (BBB) largely use incubation chambers (Transwell) separated with a filter and matrix coating to represent and to study barrier permeability. These devices have several critical shortcomings: (a) they do not reproduce critical microenvironmental parameters, primarily anatomical size or hemodynamic shear stress, (b) they often do not provide real-time visualization capability, and (c) they require a large amount of consumables. To overcome these limitations, we have developed a microfluidics based Synthetic Microvasculature model of the Blood-Brain Barrier (SyM-BBB). The SyM-BBB platform is comprised of a plastic, disposable and optically clear microfluidic chip with a microcirculation sized two-compartment chamber. The chamber is designed in such a way as to permit the realization of side-by-side apical and basolateral compartments, thereby simplifying fabrication and facilitating integration with standard instrumentation. The individually addressable apical side is seeded with endothelial cells and the basolateral side can support neuronal cells or conditioned media. In the present study, an immortalized Rat Brain Endothelial cell line (RBE4) was cultured in SyM-BBB with a perfusate of Astrocyte Conditioned Media (ACM). Biochemical analysis showed upregulation of tight junction molecules while permeation studies showed an intact BBB. Finally, transporter assay was successfully demonstrated in SyM-BBB indicating a functional model.
Collapse
|
6
|
Sansing HA, Renner NA, MacLean AG. An inverted blood-brain barrier model that permits interactions between glia and inflammatory stimuli. J Neurosci Methods 2012; 207:91-6. [PMID: 22484463 DOI: 10.1016/j.jneumeth.2012.03.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 03/27/2012] [Accepted: 03/28/2012] [Indexed: 10/28/2022]
Abstract
The blood-brain barrier (BBB) is increasingly being recognized as a site of special scientific importance. Numerous models of the BBB have been constructed over the past years with increasingly mechanistic studies of fundamental questions of cell biology and neuroimmunology. However, there has been a limiting factor of not being able to perform real-time studies of BBB function utilizing 3D models. Equally, real-time models have been limited mainly to 2D models comprised solely of endothelial cells (ECs). To measure changes in the electrical resistance across a BBB model, when adding inflammatory or stem cells which will interact with co-cultured glial cells has, to date, been beyond the capabilities of models. We have cultured an inverted BBB model with ECs on electrodes which are on the lower surface of xCELLigence Cell Invasion Migration plates. Glial cells were cultured in the basal well with foot processes extending through the filters to make contact with the ECs. SIV-infected macrophages decreased electrical resistance of the EC monolayer when added to the "parenchymal" face of the model. We present a novel inverted blood-brain barrier model that allow real time analyses of endothelial cell adhesion during modeled neuroinflammation.
Collapse
Affiliation(s)
- Hope A Sansing
- Tulane National Primate Research Center, Covington, LA, USA
| | | | | |
Collapse
|
7
|
Slater SC, Beachley V, Hayes T, Zhang D, Welsh GI, Saleem MA, Mathieson PW, Wen X, Su B, Satchell SC. An in vitro model of the glomerular capillary wall using electrospun collagen nanofibres in a bioartificial composite basement membrane. PLoS One 2011; 6:e20802. [PMID: 21731625 PMCID: PMC3123297 DOI: 10.1371/journal.pone.0020802] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Accepted: 05/13/2011] [Indexed: 01/13/2023] Open
Abstract
The filtering unit of the kidney, the glomerulus, contains capillaries whose walls function as a biological sieve, the glomerular filtration barrier. This comprises layers of two specialised cells, glomerular endothelial cells (GEnC) and podocytes, separated by a basement membrane. Glomerular filtration barrier function, and dysfunction in disease, remains incompletely understood, partly due to difficulties in studying the relevant cell types in vitro. We have addressed this by generation of unique conditionally immortalised human GEnC and podocytes. However, because the glomerular filtration barrier functions as a whole, it is necessary to develop three dimensional co-culture models to maximise the benefit of the availability of these cells. Here we have developed the first two tri-layer models of the glomerular capillary wall. The first is based on tissue culture inserts and provides evidence of cell-cell interaction via soluble mediators. In the second model the synthetic support of the tissue culture insert is replaced with a novel composite bioartificial membrane. This consists of a nanofibre membrane containing collagen I, electrospun directly onto a micro-photoelectroformed fine nickel supporting mesh. GEnC and podocytes grew in monolayers on either side of the insert support or the novel membrane to form a tri-layer model recapitulating the human glomerular capillary in vitro. These models will advance the study of both the physiology of normal glomerular filtration and of its disruption in glomerular disease.
Collapse
Affiliation(s)
- Sadie C. Slater
- Academic Renal Unit, University of Bristol, Bristol, United Kingdom
| | - Vince Beachley
- Department of Bioengineering, Clemson University, Charleston, South Carolina, United States of America
| | - Thomas Hayes
- Department of Oral and Dental Science, University of Bristol, Bristol, United Kingdom
| | - Daming Zhang
- Department of Oral and Dental Science, University of Bristol, Bristol, United Kingdom
| | - Gavin I. Welsh
- Academic Renal Unit, University of Bristol, Bristol, United Kingdom
| | - Moin A. Saleem
- Academic Renal Unit, University of Bristol, Bristol, United Kingdom
| | | | - Xuejun Wen
- Department of Bioengineering, Clemson University, Charleston, South Carolina, United States of America
| | - Bo Su
- Department of Oral and Dental Science, University of Bristol, Bristol, United Kingdom
| | | |
Collapse
|
8
|
Xie H, Xue YX, Liu LB, Liu YH, Wang P. Role of RhoA/ROCK signaling in endothelial-monocyte-activating polypeptide II opening of the blood-tumor barrier: role of RhoA/ROCK signaling in EMAP II opening of the BTB. J Mol Neurosci 2011; 46:666-76. [PMID: 21647708 DOI: 10.1007/s12031-011-9564-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 05/23/2011] [Indexed: 11/25/2022]
Abstract
The purpose of the present study was to determine the potential for RhoA/ROCK signaling to play a role in endothelial-monocyte-activating polypeptide (EMAP) II-induced increase in blood-tumor barrier (BTB) permeability in rat brain microvascular endothelial cells (RBMECs). In the present study, we used an in vitro BTB model, a RhoA inhibitor (C3 exoenzyme) and a ROCK inhibitor (Y27632) to determine whether RhoA/ROCK pathway play a role in the process of TJ disassembly, stress fiber formation, MLC and cofilin phosphorylation, as well as increase of BTB permeability induced by EMAP II. The results revealed that BTB permeability was increased by EMAP II induction, and C3 exoenzyme or Y27632 could partially inhibit the EMAP II-induced increase of BTB permeability. The significant down-regulations in tight junction (TJ)-associated proteins occludin, claudin-5 and ZO-1 and stress fiber formation by EMAP II administration were observed, which were partly prevented by C3 exoenzyme or Y27632 pretreatment. Moreover, the significant increases in RhoA activity, myosin light chain (MLC) and cofilin phosphorylation by EMAP II administration were observed, MLC and cofilin phosphorylation were partly inhibited by C3 exoenzyme or Y27632 pretreatment. The present study demonstrates that the activation of RhoA/ROCK signaling in RBMECs was required for the increase of BTB permeability and these effects are related with the ability for RhoA/ROCK to mediate TJ disassembly and stress fiber formation by phosphorylating cofilin and MLC.
Collapse
Affiliation(s)
- Hui Xie
- Department of Neurobiology, College of Basic Medicine, China Medical University, Shenyang, Liaoning Province, People's Republic of China, 110001
| | | | | | | | | |
Collapse
|
9
|
Increasing of blood-tumor barrier permeability through paracellular pathway by low-frequency ultrasound irradiation in vitro. J Mol Neurosci 2010; 43:541-8. [PMID: 21104456 DOI: 10.1007/s12031-010-9479-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Accepted: 11/10/2010] [Indexed: 10/18/2022]
Abstract
The research was conducted to study the increase of blood-tumor barrier (BTB) permeability through paracellular pathway by low-frequency ultrasound (LFU) irradiation in vitro. LFU (frequency=1.0 MHz) was performed to irradiate BTB model from the co-culture of rat C6 glioma cells and rat brain microvascular endothelial cells (RBMECs). The permeability of BTB was measured by transendothelial electrical resistance (TEER) and flux of horseradish peroxidase (HRP) assays after LFU irradiation. Western-blotting, immunohistochemistry, and immunofluorescence assays were used to investigate the changes of expressions and distributions of tight junction (TJ)-associated proteins ZO-1, occludin, and claudin-5. The TEER value began to decrease, and the minimum value appeared at 2 h, then gradually returned to the original level at 24 h after LFU irradiation. With time, flux of HRP gradually increased and reached the peak 2 h after LFU irradiation. The expressions of ZO-1, occludin, and claudin-5 in RBMECs decreased, and decreased most significantly at 2 h, then gradually restored to the original level at 24 h. Meanwhile, they were discontinuously distributed in the cellular boundaries after LFU irradiation. In summary, the expression of TJ-associated proteins was down-regulated, TJ was opened, and the permeability of BTB was increased through paracellular pathway by LFU irradiation.
Collapse
|
10
|
Liu LB, Xue YX, Liu YH, Wang YB. Bradykinin increases blood-tumor barrier permeability by down-regulating the expression levels of ZO-1, occludin, and claudin-5 and rearranging actin cytoskeleton. J Neurosci Res 2008; 86:1153-68. [PMID: 18183615 DOI: 10.1002/jnr.21558] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Bradykinin (BK) has been shown to open blood-tumor barrier (BTB) selectively and to increase permeability of the BTB transiently, but the mechanism is unclear. This study was performed to determine whether BK opens the BTB by affecting the tight junction (TJ)-associated proteins zonula occluden-1 (ZO-1), occludin, and caludin-5 and cytoskeleton protein filamentous actin (F-actin). In rat brain glioma model and BTB model in vitro, we find that the protein expression levels of ZO-1, occludin, and claudin-5 are attenuated by BK induction. Immunohistochemistry and immunofluorescence assays show that the attenuated expression of ZO-1, occludin, and claudin-5 and F-actin is most obvious in the smaller tumor capillaries (<20 microm) after BK infusion, and there is no change in the larger tumor capillaries (>20 microm). The redistribution of ZO-1, occludin, and claudin-5 and rearrangement of F-actin in brain microvascular endothelial cells are observed at the same time. Meanwhile, Evans blue assay shows that the permeability of BTB increases after BK infusion. Transmission electron microscopy indicates that TJ is opened and that pinocytotic vesicular density is increased. Transendothelial electrical resistance (TEER) and horseradish peroxidase flux assays also reveal that TJ is opened by BK induction. In addition, radioimmunity and Western blot assay reveal a significant decrease in expression levels of cAMP and catalytic subunit of protien kinase A (PKAcs) of tumor tissue. This study demonstrates that the increase of BK-mediated BTB permeability is associated with the down-regulation of ZO-1, occludin, and claudin-5 and the rearrangement of F-actin and that cAMP/PKA signal transduction system might be involved in the modulating process.
Collapse
Affiliation(s)
- Li-Bo Liu
- Department of Neurobiology, College of Basic Medicine, China Medical University, Shenyang, People's Republic of China
| | | | | | | |
Collapse
|
11
|
Song L, Ge S, Pachter JS. Caveolin-1 regulates expression of junction-associated proteins in brain microvascular endothelial cells. Blood 2006; 109:1515-23. [PMID: 17023578 PMCID: PMC1794065 DOI: 10.1182/blood-2006-07-034009] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Recent evidence from this laboratory indicated that reduced expression of caveolin-1 accompanied the diminished expression of tight junction (TJ)-associated proteins occludin and zonula occludens-1 (ZO-1) following stimulation of brain microvascular endothelial cells (BMECs) with the chemokine CCL2 (formerly called MCP-1). Because attenuated caveolin-1 levels have also been correlated with heightened permeability of other endothelia, the objective of this study was to test the hypothesis that reduced caveolin-1 expression is causally linked to the action of CCL2 on BMEC junctional protein expression and barrier integrity. This was achieved using adenovirus to nondestructively deliver caveolin-1 siRNA (Ad-siCav-1) to BMEC monolayers, which model the blood-brain barrier (BBB). Treatment with siRNA reduced the caveolin-1 protein level as well as occludin and ZO-1. Additionally, occludin exhibited dissociation from the cytoskeletal framework. These changes were attended by comparable alterations in adherens junction (AJ)-associated proteins, VE-cadherin and beta-catenin, increased BMEC paracellular permeability, and facilitated the ability of CCL2 to stimulate monocytic transendothelial migration. Furthermore, treating BMECs with cavtratin, a synthetic cell-permeable peptide encoding the caveolin-1 scaffolding domain, antagonized effects of both Ad-siCav-1 and CCL2. These results collectively highlight caveolin-1 loss as a critical step in CCL2-induced modulation of BMEC junctional protein expression and integrity, and possibly serve a crucial role in regulating inflammation at the BBB.
Collapse
Affiliation(s)
- Li Song
- Blood-Brain Barrier Laboratory, Department of Pharmacology, University of Connecticut Health Center, Farmington 06030, USA
| | | | | |
Collapse
|
12
|
Paye JMD, Forsten-Williams K. Regulation of insulin-like growth factor-I (IGF-I) delivery by IGF binding proteins and receptors. Ann Biomed Eng 2006; 34:618-32. [PMID: 16547609 DOI: 10.1007/s10439-005-9064-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2005] [Accepted: 10/19/2005] [Indexed: 11/27/2022]
Abstract
Delivery of growth factors via the bloodstream for the treatment of various diseases is regulated in part by interactions with cell surface binding elements. Understanding the kinetics of growth factor binding and transport by cells would, therefore, be advantageous. This report quantifies the binding, internalization, and transport of insulin-like growth factor-I (IGF-I) across bovine aortic endothelial cells (BAEC) cultured in vitro. Binding analysis indicated that IGF binding proteins (IGFBPs), primarily localized with the extracellular matrix, were the primary IGF-I binding elements in our system, with twice as many binding sites (8.0 +/- 1.9 x 10(4) per cell) as IGF-I receptors (IGF-IR) (3.9 +/- 0.6 x 10(4) per cell). Internalization of IGF-I by IGF-IR, but not IGFBPs, was detected, however both receptor and IGFBP binding were shown to inhibit rather than enhance the transport of intact IGF-I, albeit in different ways. IGFBPs retained IGF-I in the apical region while IGF-IR binding led to protein degradation. Based on our computational modeling and experimental data, we hypothesize that IGFBPs could function as a reservoir for IGF-I, sequestering it for later release and transport, and that this reservoir function of the IGFBPs could be used to promote controlled localized delivery of IGF-I.
Collapse
Affiliation(s)
- Julie M D Paye
- Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA.
| | | |
Collapse
|
13
|
Pachter JS, de Vries HE, Fabry Z. The blood-brain barrier and its role in immune privilege in the central nervous system. J Neuropathol Exp Neurol 2003; 62:593-604. [PMID: 12834104 DOI: 10.1093/jnen/62.6.593] [Citation(s) in RCA: 185] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The blood-brain barrier (BBB) provides both anatomical and physiological protection for the central nervous system (CNS), strictly regulating the entry of many substances and blood borne cells into the nervous tissue. Increased understanding of how the unique microenvironment in the CNS influences the BBB is crucial for developing novel therapeutic approaches to CNS diseases. In this review, we discuss those characteristics of the BBB that play an important role in maintaining immune privilege in the CNS, as well as factors that regulate immune cell invasion through the BBB and thereby modulate immune responses in the nervous tissue. In general, immune cell invasion across the BBB is highly restricted and carefully regulated. A florid invasion of activated white blood cells can create a predominantly proinflammatory local environment in the CNS, leading to immune-mediated diseases of the nervous tissue. Recent developments in cellular and molecular biological methods have allowed closer analysis of BBB function, and led to an improved understanding of the active role of the BBB in immune-mediated diseases of the CNS.
Collapse
Affiliation(s)
- Joel S Pachter
- University of Connecticut Health Center, Farmington, Connecticut, USA
| | | | | |
Collapse
|
14
|
Andjelkovic AV, Zochowski MR, Morgan F, Pachter JS. Qualitative and quantitative analysis of monocyte transendothelial migration by confocal microscopy and three-dimensional image reconstruction. In Vitro Cell Dev Biol Anim 2001; 37:111-20. [PMID: 11332736 DOI: 10.1290/1071-2690(2001)037<0111:qaqaom>2.0.co;2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A novel method for qualitative and quantitative analysis of monocyte transendothelial migration is described. By labeling monocytes and endothelial cells with different fluorophores, and utilizing confocal microscopy and three-dimensional image reconstruction, transmigrating monocytes were resolved and quantified within a subendothelial collagen gel. Comparison of monocyte migration across endothelial monolayers derived from human brain microvessels versus umbilical veins revealed diapedesis across brain endothelium to be significantly delayed. Inclusion of astrocytes within the subendothelial collagen gel resulted in the formation of an array of astrocytic processes that simulated the glia limitans surrounding brain microvessels in situ, thus yielding a more physiologic paradigm of the blood-brain barrier. By virtue of its unique capacity to provide information on the total number of migrating cells, this analytic approach overcomes significant caveats associated with sampling only aspects of the migration process. The potential adaptability of this method to computer-assisted analysis further enhances its prospective use in high-throughput screening.
Collapse
Affiliation(s)
- A V Andjelkovic
- Department of Pharmacology, University of Connecticut Health Center, Farmington 06030, USA
| | | | | | | |
Collapse
|
15
|
Song J, Rolfe BE, Hayward IP, Campbell GR, Campbell JH. Effects of collagen gel configuration on behavior of vascular smooth muscle cells in vitro: association with vascular morphogenesis. In Vitro Cell Dev Biol Anim 2000; 36:600-10. [PMID: 11212145 DOI: 10.1007/bf02577528] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The growth, behavior, and contractile protein expression of rabbit aortic smooth muscle cells (SMC) grown on, between layers, or within a collagen gel was investigated by confocal laser scanning fluorescence microscopy and Western analysis. SMC grown on collagen gel behaved similarly to those on conventional culture dishes. However, when a second layer of collagen was overlaid, cells underwent an elongated quiescent phase before onset of proliferation and a more than threefold lower logarithmic growth rate was observed. These cells self-organized into a network with ring-like structures. With increasing culture time, some of the rings developed into funnel-like, incomplete or complete tubular structures. If a tubular template preexisted within the gel, the SMC established a cylinder-shaped tube with several circularly arranged muscular layers (similar to an artery wall). This behavior mimicked endothelial cells during angiogenesis in vitro. A similar phenomenon occurred in cultures in which SMC were randomly mixed in a collagen gel, but here their behavior and morphology varied with their position within the gel. Western blot analysis showed that the SMC differentiation marker, smooth muscle myosin heavy chain-2 (SM-2), rapidly decreased, disappearing by day 10 in SMC grown on collagen, but was still detectable until day 25 in cells cultured between or within the same gel. These findings indicate that like endothelial cells, vascular SMC can display blood vessel formation behavior in vitro when an appropriate three-dimensional matrix environment is provided to keep them in a relatively higher-differentiated and low-proliferative state.
Collapse
Affiliation(s)
- J Song
- Department of Anatomical Sciences, University of Queensland, Brisbane, Australia
| | | | | | | | | |
Collapse
|
16
|
SONG JIAN, ROLFE BARBARAE, HAYWARD IANP, CAMPBELL GORDONR, CAMPBELL JULIEH. EFFECTS OF COLLAGEN GEL CONFIGURATION ON BEHAVIOR OF VASCULAR SMOOTH MUSCLE CELLS IN VITRO: ASSOCIATION WITH VASCULAR MORPHOGENESIS. ACTA ACUST UNITED AC 2000. [DOI: 10.1290/1071-2690(2000)036<0600:eocgco>2.0.co;2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
17
|
Zhao L, Zhang MM, Ng KY. Effects of vascular permeability factor on the permeability of cultured endothelial cells from brain capillaries. J Cardiovasc Pharmacol 1998; 32:1-4. [PMID: 9676713 DOI: 10.1097/00005344-199807000-00001] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The effects of vascular permeability factor (VPF) on the blood-brain barrier (BBB) permeability were studied in cultured capillary endothelial cells from bovine brain. When VPF was added to the abluminal or brain side of the BBB, a rapid increase in the BBB permeability was observed. This increase in the BBB permeability is dependent on the concentration of the VPF used and is reversible on removal of the VPF. Contrarily, when VPF was added to the luminal or blood side of the BBB, no increase in the BBB permeability was observed. These results suggest that the receptors for VPF are located on the abluminal side of the BBB.
Collapse
Affiliation(s)
- L Zhao
- Department of Pharmaceutical Sciences, University of Colorado Health Sciences Center, Denver, USA
| | | | | |
Collapse
|
18
|
Duport S, Robert F, Muller D, Grau G, Parisi L, Stoppini L. An in vitro blood-brain barrier model: cocultures between endothelial cells and organotypic brain slice cultures. Proc Natl Acad Sci U S A 1998; 95:1840-5. [PMID: 9465104 PMCID: PMC19200 DOI: 10.1073/pnas.95.4.1840] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
This communication describes a novel in vitro blood-brain barrier (BBB) model: organotypic slice cultures from the central nervous system were overlaid on endothelial cell monolayers grown on permeable membranes. Morphological, electrophysiological, and microdialysis approaches were carried out to characterize and validate this model. After 10 days in coculture, morphological studies reveal the presence of tight junctions. Electrophysiological recordings of neuronal activity performed on organotypic cultures with or without an endothelial cell monolayer show that amplitude of evoked responses were comparable, indicating good viability of cocultures after 2 weeks. Perfusion of known BBB permeable or nonpermeable molecules was used to test the coculture tightness in conjunction with electrophysiological or microdialysis approaches: application of glutamate (Glu), which doesn't easily cross the BBB, triggers off rhythmic activity only in control cultures, whereas epileptogenic activity was observed in both control cultures and cocultures during perfusions with picrotoxin, a molecule that can diffuse through the BBB. Finally, the microdialysis technique was used to determine the permeability of molecules coming from the perfusion chamber: L-dopa, dopamine, and Glu were employed to assess the selective permeability of the coculture model. Thus, these results indicate that the in vitro model described possesses characteristics similar to those of the BBB in situ and that cocultures of organotypic slices and endothelial cell monolayers have potential as a powerful tool for studying biochemical mechanisms regulating BBB function and drug delivery to the central nervous system.
Collapse
Affiliation(s)
- S Duport
- Department of Pharmacology, Centre Médical Universitaire, CH-1211 Geneva 4, Switzerland
| | | | | | | | | | | |
Collapse
|
19
|
de Boer A, Breimer D. Reconstitution of the blood-brain barrier in cell culture for studies of drug transport and metabolism. Adv Drug Deliv Rev 1996. [DOI: 10.1016/s0169-409x(96)00421-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
|
20
|
Biegel D, Spencer DD, Pachter JS. Isolation and culture of human brain microvessel endothelial cells for the study of blood-brain barrier properties in vitro. Brain Res 1995; 692:183-9. [PMID: 8548302 DOI: 10.1016/0006-8993(95)00511-n] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A simplified protocol for isolating brain microvessel endothelial cells (BMEC) from human cortex and culturing them on a thick collagen plug is described. This method results in the establishment of monolayers of BMEC that retain numerous properties indicative of the blood-brain barrier (BBB) phenotype, such as elevated transendothelial electrical resistance, attenuated paracellular flux of sucrose, peripheral actin filament distribution and asymmetric localization of the efflux peptide, P-glycoprotein, to the apical (luminal) BMEC surface. The novel 3-dimensional nature of this model system renders it ideally suitable for assaying such varied aspects of BBB physiology as solute transport, pathogen penetrance, leukocyte infiltration and tumor metastasis into the brain. Moreover, the fact that the system is derived from human brain allows for the study of pathogenetic mechanisms that may only be operative in humans.
Collapse
Affiliation(s)
- D Biegel
- Department of Physiology, University of Connecticut Health Center, Farmington 06030, USA
| | | | | |
Collapse
|