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Wilhelm I, Nyúl-Tóth Á, Kozma M, Farkas AE, Krizbai IA. Role of pattern recognition receptors of the neurovascular unit in inflamm-aging. Am J Physiol Heart Circ Physiol 2017; 313:H1000-H1012. [PMID: 28801521 DOI: 10.1152/ajpheart.00106.2017] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 08/09/2017] [Accepted: 08/09/2017] [Indexed: 01/18/2023]
Abstract
Aging is associated with chronic inflammation partly mediated by increased levels of damage-associated molecular patterns, which activate pattern recognition receptors (PRRs) of the innate immune system. Furthermore, many aging-related disorders are associated with inflammation. PRRs, such as Toll-like receptors (TLRs) and nucleotide-binding oligomerization domain-like receptors (NLRs), are expressed not only in cells of the innate immune system but also in other cells, including cells of the neurovascular unit and cerebral vasculature forming the blood-brain barrier. In this review, we summarize our present knowledge about the relationship between activation of PRRs expressed by cells of the neurovascular unit-blood-brain barrier, chronic inflammation, and aging-related pathologies of the brain. The most important damage-associated molecular pattern-sensing PRRs in the brain are TLR2, TLR4, and NLR family pyrin domain-containing protein-1 and pyrin domain-containing protein-3, which are activated during physiological and pathological aging in microglia, neurons, astrocytes, and possibly endothelial cells and pericytes.
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Affiliation(s)
- Imola Wilhelm
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary; and .,Institute of Life Sciences, Vasile Goldiş Western University of Arad, Arad, Romania
| | - Ádám Nyúl-Tóth
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary; and
| | - Mihály Kozma
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary; and
| | - Attila E Farkas
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary; and
| | - István A Krizbai
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary; and.,Institute of Life Sciences, Vasile Goldiş Western University of Arad, Arad, Romania
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102
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Nyúl-Tóth Á, Kozma M, Nagyőszi P, Nagy K, Fazakas C, Haskó J, Molnár K, Farkas AE, Végh AG, Váró G, Galajda P, Wilhelm I, Krizbai IA. Expression of pattern recognition receptors and activation of the non-canonical inflammasome pathway in brain pericytes. Brain Behav Immun 2017; 64:220-231. [PMID: 28432035 DOI: 10.1016/j.bbi.2017.04.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 03/31/2017] [Accepted: 04/12/2017] [Indexed: 12/27/2022] Open
Abstract
Cerebral pericytes are mural cells embedded in the basement membrane of capillaries. Increasing evidence suggests that they play important role in controlling neurovascular functions, i.e. cerebral blood flow, angiogenesis and permeability of the blood-brain barrier. These cells can also influence neuroinflammation which is highly regulated by the innate immune system. Therefore, we systematically tested the pattern recognition receptor expression of brain pericytes. We detected expression of NOD1, NOD2, NLRC5, NLRP1-3, NLRP5, NLRP9, NLRP10 and NLRX mRNA in non-treated cells. Among the ten known human TLRs, TLR2, TLR4, TLR5, TLR6 and TLR10 were found to be expressed. Inflammatory mediators induced the expression of NLRA, NLRC4 and TLR9 and increased the levels of NOD2, TLR2, inflammasome-forming caspases and inflammasome-cleaved interleukins. Oxidative stress, on the other hand, upregulated expression of TLR10 and NLRP9. Activation of selected pattern recognition receptors can lead to inflammasome assembly and caspase-dependent secretion of IL-1β. TNF-α and IFN-γ increased the levels of pro-IL-1β and pro-caspase-1 proteins; however, no canonical activation of NLRP1, NLRP2, NLRP3 or NLRC4 inflammasomes could be observed in human brain vascular pericytes. On the other hand, we could demonstrate secretion of active IL-1β in response to non-canonical inflammasome activation, i.e. intracellular LPS or infection with E. coli bacteria. Our in vitro results indicate that pericytes might have an important regulatory role in neuroinflammation.
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Affiliation(s)
- Ádám Nyúl-Tóth
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726 Szeged, Hungary.
| | - Mihály Kozma
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726 Szeged, Hungary.
| | - Péter Nagyőszi
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726 Szeged, Hungary.
| | - Krisztina Nagy
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726 Szeged, Hungary.
| | - Csilla Fazakas
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726 Szeged, Hungary.
| | - János Haskó
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726 Szeged, Hungary.
| | - Kinga Molnár
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726 Szeged, Hungary.
| | - Attila E Farkas
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726 Szeged, Hungary.
| | - Attila G Végh
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726 Szeged, Hungary.
| | - György Váró
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726 Szeged, Hungary.
| | - Péter Galajda
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726 Szeged, Hungary.
| | - Imola Wilhelm
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726 Szeged, Hungary; Institute of Life Sciences, Vasile Goldiş Western University of Arad, Str. Liviu Rebreanu 86, 310414 Arad, Romania.
| | - István A Krizbai
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726 Szeged, Hungary; Institute of Life Sciences, Vasile Goldiş Western University of Arad, Str. Liviu Rebreanu 86, 310414 Arad, Romania.
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103
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Fatty Acid-Binding Protein 5 at the Blood-Brain Barrier Regulates Endogenous Brain Docosahexaenoic Acid Levels and Cognitive Function. J Neurosci 2017; 36:11755-11767. [PMID: 27852782 DOI: 10.1523/jneurosci.1583-16.2016] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 09/22/2016] [Accepted: 09/24/2016] [Indexed: 11/21/2022] Open
Abstract
Fatty acid-binding protein 5 (FABP5) at the blood-brain barrier contributes to the brain uptake of docosahexaenoic acid (DHA), a blood-derived polyunsaturated fatty acid essential for maintenance of cognitive function. Given the importance of DHA in cognition, the aim of this study was to investigate whether deletion of FABP5 results in cognitive dysfunction and whether this is associated with reduced brain endothelial cell uptake of exogenous DHA and subsequent attenuation in the brain levels of endogenous DHA. Cognitive function was assessed in male and female FABP5+/+ and FABP5-/- mice using a battery of memory paradigms. FABP5-/- mice exhibited impaired working memory and short-term memory, and these cognitive deficits were associated with a 14.7 ± 5.7% reduction in endogenous brain DHA levels. The role of FABP5 in the blood-brain barrier transport of DHA was assessed by measuring 14C-DHA uptake into brain endothelial cells and capillaries isolated from FABP5+/+ and FABP5-/- mice. In line with a crucial role of FABP5 in the brain uptake of DHA, 14C-DHA uptake into brain endothelial cells and brain capillaries of FABP5-/- mice was reduced by 48.4 ± 14.5% and 14.0 ± 4.2%, respectively, relative to those of FABP5+/+ mice. These results strongly support the hypothesis that FABP5 is essential for maintaining brain endothelial cell uptake of DHA, and that cognitive deficits observed in FABP5-/- mice are associated with reduced CNS access of DHA. SIGNIFICANCE STATEMENT Genetic deletion of fatty acid-binding protein 5 (FABP5) in mice reduces uptake of exogenous docosahexaenoic acid (DHA) into brain endothelial cells and brain capillaries and reduces brain parenchymal levels of endogenous DHA. Therefore, FABP5 in the brain endothelial cell is a crucial contributor to the brain levels of DHA. Critically, lowered brain DHA levels in FABP5-/- mice occurred in tandem with cognitive deficits in a battery of memory paradigms. This study provides evidence of a critical role for FABP5 in the maintenance of cognitive function via regulating the brain uptake of DHA, and suggests that upregulation of FABP5 in neurodegenerative diseases, where brain DHA levels are possibly diminished (e.g., Alzheimer's disease), may provide a novel therapeutic approach for restoring cognitive function.
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104
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Freskgård PO, Urich E. Antibody therapies in CNS diseases. Neuropharmacology 2017; 120:38-55. [DOI: 10.1016/j.neuropharm.2016.03.014] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 02/05/2016] [Accepted: 03/07/2016] [Indexed: 12/22/2022]
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105
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Bhowmik A, Chakravarti S, Ghosh A, Shaw R, Bhandary S, Bhattacharyya S, Sen PC, Ghosh MK. Anti-SSTR2 peptide based targeted delivery of potent PLGA encapsulated 3,3'-diindolylmethane nanoparticles through blood brain barrier prevents glioma progression. Oncotarget 2017; 8:65339-65358. [PMID: 29029435 PMCID: PMC5630335 DOI: 10.18632/oncotarget.18689] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 05/22/2017] [Indexed: 12/27/2022] Open
Abstract
Current therapy for Glioblastoma is insufficient because of the presence of blood brain barrier. It limits the transport of essential drugs to the tumor sites. To overcome this limitation we strategized the delivery of an anticancer compound 3,3’-diindolylmethane by encapsulation in poly (lactic-co-glycolic acid) nanoparticles. These nanoparticles were tagged with a novel peptide against somatostatin receptor 2 (SSTR2), a potential target in glioma. The nanoformulation (27-87nm) had loading and encapsulation efficiency of 7.2% and 70% respectively. It was successfully internalized inside the glioma cells resulting in apoptosis. Furthermore, an in vivo bio-distribution study revealed the selective accumulation of the nanoformulation into rat brain tumor sites by crossing the blood brain barrier. This resulted in abrogation of epidermal growth factor receptor pathway activation in glioma cells. Our novel nanopreparation therefore shows great promise to serve as a template for targeted delivery of other therapeutics in treating GBM.
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Affiliation(s)
- Arijit Bhowmik
- Signal Transduction in Cancer and Stem Cells Laboratory, Translational Research Unit of Excellence (TRUE), Division of Cancer Biology and Inflammatory Disorder, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology (CSIR-IICB), Kolkata 700091, India
| | - Sayak Chakravarti
- Signal Transduction in Cancer and Stem Cells Laboratory, Translational Research Unit of Excellence (TRUE), Division of Cancer Biology and Inflammatory Disorder, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology (CSIR-IICB), Kolkata 700091, India
| | - Aparajita Ghosh
- Division of Molecular Medicine, Bose Institute, Centenary Campus, Kolkata 700054, India
| | - Rajni Shaw
- Signal Transduction in Cancer and Stem Cells Laboratory, Translational Research Unit of Excellence (TRUE), Division of Cancer Biology and Inflammatory Disorder, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology (CSIR-IICB), Kolkata 700091, India
| | - Suman Bhandary
- Division of Molecular Medicine, Bose Institute, Centenary Campus, Kolkata 700054, India
| | | | - Parimal C Sen
- Division of Molecular Medicine, Bose Institute, Centenary Campus, Kolkata 700054, India
| | - Mrinal K Ghosh
- Signal Transduction in Cancer and Stem Cells Laboratory, Translational Research Unit of Excellence (TRUE), Division of Cancer Biology and Inflammatory Disorder, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology (CSIR-IICB), Kolkata 700091, India
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106
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Lauschke K, Frederiksen L, Hall VJ. Paving the Way Toward Complex Blood-Brain Barrier Models Using Pluripotent Stem Cells. Stem Cells Dev 2017; 26:857-874. [PMID: 28398169 DOI: 10.1089/scd.2017.0003] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
A tissue with great need to be modeled in vitro is the blood-brain barrier (BBB). The BBB is a tight barrier that covers all blood vessels in the brain and separates the brain microenvironment from the blood system. It consists of three cell types [neurovascular unit (NVU)] that contribute to the unique tightness and selective permeability of the BBB and has been shown to be disrupted in many diseases and brain disorders, such as vascular dementia, stroke, multiple sclerosis, and Alzheimer's disease. Given the progress that pluripotent stem cells (PSCs) have made in the past two decades, it is now possible to produce many cell types from the BBB and even partially recapitulate this complex tissue in vitro. In this review, we summarize the most recent developments in PSC differentiation and modeling of the BBB. We also suggest how patient-specific human-induced PSCs could be used to model BBB dysfunction in the future. Lastly, we provide perspectives on how to improve production of the BBB in vitro, for example by improving pericyte differentiation protocols and by better modeling the NVU in the dish.
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Affiliation(s)
- Karin Lauschke
- 1 National Food Institute, Technical University of Denmark , Kongens Lyngby, Denmark
- 2 Department of Micro- and Nanotechnology, Technical University of Denmark , Kongens Lyngby, Denmark
| | - Lise Frederiksen
- 3 Faculty of Health and Medical Sciences, University of Copenhagen , København N, Denmark
| | - Vanessa Jane Hall
- 4 Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen , Frederiksberg C, Denmark
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107
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Cao Y, Gong Y, Liu L, Zhou Y, Fang X, Zhang C, Li Y, Li J. The use of human umbilical vein endothelial cells (HUVECs) as an in vitro
model to assess the toxicity of nanoparticles to endothelium: a review. J Appl Toxicol 2017; 37:1359-1369. [DOI: 10.1002/jat.3470] [Citation(s) in RCA: 168] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Accepted: 02/23/2017] [Indexed: 12/30/2022]
Affiliation(s)
- Yi Cao
- Key Laboratory of Environment-Friendly Chemistry and Applications of Ministry Education, Laboratory of Biochemistry, College of Chemistry; Xiangtan University; Xiangtan 411105 China
- Institute of Bast Fiber Crops; Chinese Academy of Agricultural Sciences; Changsha 410205 China
| | - Yu Gong
- Key Laboratory of Environment-Friendly Chemistry and Applications of Ministry Education, Laboratory of Biochemistry, College of Chemistry; Xiangtan University; Xiangtan 411105 China
| | - Liangliang Liu
- Institute of Bast Fiber Crops; Chinese Academy of Agricultural Sciences; Changsha 410205 China
| | - Yiwei Zhou
- Key Laboratory of Environment-Friendly Chemistry and Applications of Ministry Education, Laboratory of Biochemistry, College of Chemistry; Xiangtan University; Xiangtan 411105 China
- Institute of Bast Fiber Crops; Chinese Academy of Agricultural Sciences; Changsha 410205 China
| | - Xin Fang
- Key Laboratory of Environment-Friendly Chemistry and Applications of Ministry Education, Laboratory of Biochemistry, College of Chemistry; Xiangtan University; Xiangtan 411105 China
- Institute of Bast Fiber Crops; Chinese Academy of Agricultural Sciences; Changsha 410205 China
| | - Cao Zhang
- Key Laboratory of Environment-Friendly Chemistry and Applications of Ministry Education, Laboratory of Biochemistry, College of Chemistry; Xiangtan University; Xiangtan 411105 China
| | - Yining Li
- Key Laboratory of Environment-Friendly Chemistry and Applications of Ministry Education, Laboratory of Biochemistry, College of Chemistry; Xiangtan University; Xiangtan 411105 China
| | - Juan Li
- Key Laboratory of Environment-Friendly Chemistry and Applications of Ministry Education, Laboratory of Biochemistry, College of Chemistry; Xiangtan University; Xiangtan 411105 China
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108
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Meyer K, Kaspar BK. Glia-neuron interactions in neurological diseases: Testing non-cell autonomy in a dish. Brain Res 2017; 1656:27-39. [PMID: 26778174 PMCID: PMC4939136 DOI: 10.1016/j.brainres.2015.12.051] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 12/17/2015] [Accepted: 12/22/2015] [Indexed: 12/30/2022]
Abstract
For the past century, research on neurological disorders has largely focused on the most prominently affected cell types - the neurons. However, with increasing knowledge of the diverse physiological functions of glial cells, their impact on these diseases has become more evident. Thus, many conditions appear to have more complex origins than initially thought. Since neurological pathologies are often sporadic with unknown etiology, animal models are difficult to create and might only reflect a small portion of patients in which a mutation in a gene has been identified. Therefore, reliable in vitro systems to studying these disorders are urgently needed. They might be a pre-requisite for improving our understanding of the disease mechanisms as well as for the development of potential new therapies. In this review, we will briefly summarize the function of different glial cell types in the healthy central nervous system (CNS) and outline their implication in the development or progression of neurological conditions. We will then describe different types of culture systems to model non-cell autonomous interactions in vitro and evaluate advantages and disadvantages. This article is part of a Special Issue entitled SI: Exploiting human neurons.
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Affiliation(s)
- Kathrin Meyer
- The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Brian K Kaspar
- The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA; Molecular, Cellular & Developmental Biology Graduate Program, The Ohio State University, Columbus, OH, USA; Department of Neuroscience, The Ohio State University, Columbus, OH, USA.
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109
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Adriani G, Ma D, Pavesi A, Kamm RD, Goh ELK. A 3D neurovascular microfluidic model consisting of neurons, astrocytes and cerebral endothelial cells as a blood-brain barrier. LAB ON A CHIP 2017; 17:448-459. [PMID: 28001148 DOI: 10.1039/c6lc00638h] [Citation(s) in RCA: 283] [Impact Index Per Article: 40.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The neurovascular unit is a complex, interdependent system composed of neurons and neural supporting cells, such as astrocytes, as well as cells that comprise the vascular system including endothelial cells, pericytes, and smooth muscle cells. Each cell type in the neurovascular unit plays an essential role, either in transmitting and processing neural signals or in maintaining the appropriate microenvironmental conditions for healthy neural function. In vitro neurovascular models can be useful for understanding the different roles and functions of the cells composing the neurovascular unit, as well as for assessing the effects on neural function of therapeutic compounds after crossing the endothelial barrier. Here, we report a novel three-dimensional neurovascular microfluidic model consisting of primary rat astrocytes and neurons together with human cerebral microvascular endothelial cells. These three cell types in our neurovascular chip (NVC) show distinct cell type-specific morphological characteristics and functional properties. In particular, morphological and functional analysis of neurons enables quantitative assessment of neuronal responses, while human cerebral endothelial cells form monolayers with size-selective permeability similar to existing in vitro blood-brain barrier (BBB) models.
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Affiliation(s)
- Giulia Adriani
- Singapore-MIT Alliance for Research and Technology, 138602 Singapore
| | - Dongliang Ma
- Department of Research, National Neuroscience Institute, 20 College Road, 169856 Singapore and Neuroscience Academic Clinical Programme, Duke-NUS Medical School, 169857 Singapore.
| | - Andrea Pavesi
- Singapore-MIT Alliance for Research and Technology, 138602 Singapore
| | - Roger D Kamm
- Singapore-MIT Alliance for Research and Technology, 138602 Singapore and Massachusetts Institute of Technology, Cambridge, MA, 02139 USA.
| | - Eyleen L K Goh
- Department of Research, National Neuroscience Institute, 20 College Road, 169856 Singapore and Neuroscience Academic Clinical Programme, Duke-NUS Medical School, 169857 Singapore. and Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597 Singapore and KK Research Center, KK Women's and Children's Hospital, Singapore 229899, Singapore
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110
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Current Strategies for the Delivery of Therapeutic Proteins and Enzymes to Treat Brain Disorders. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2017; 137:1-28. [DOI: 10.1016/bs.irn.2017.08.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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111
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Tornabene E, Brodin B. Stroke and Drug Delivery--In Vitro Models of the Ischemic Blood-Brain Barrier. J Pharm Sci 2016; 105:398-405. [PMID: 26869407 DOI: 10.1016/j.xphs.2015.11.041] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 11/20/2015] [Accepted: 11/20/2015] [Indexed: 12/11/2022]
Abstract
Stroke is a major cause of death and disability worldwide. Both cerebral hypoperfusion and focal cerebral infarcts are caused by a reduction of blood flow to the brain, leading to stroke and subsequent brain damage. At present, only few medical treatments of stroke are available, with the Food and Drug Administration-approved tissue plasminogen activator for treatment of acute ischemic stroke being the most prominent example. A large number of potential drug candidates for treatment of ischemic brain tissue have been developed and subsequently failed in clinical trials. A deeper understanding of permeation pathways across the barrier in ischemic and postischemic brain endothelium is important for development of new medical treatments. The blood-brain barrier, that is, the endothelial monolayer lining the brain capillaries, changes properties during an ischemic event. In vitro models of the blood-brain barrier are useful tools to investigate the effects of induced ischemia under controlled conditions. In the present mini review, we aim to give a brief overview of the in vitro models of ischemia. Special focus is given to the expression of uptake and efflux transport pathways in the ischemic and postischemic endothelium. Finally, we will point toward future challenges within the field of in vitro models of brain ischemia.
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Affiliation(s)
- Erica Tornabene
- Section of Pharmaceutical Design and Drug Delivery, Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Birger Brodin
- Section of Pharmaceutical Design and Drug Delivery, Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark.
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112
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McConnell HL, Kersch CN, Woltjer RL, Neuwelt EA. The Translational Significance of the Neurovascular Unit. J Biol Chem 2016; 292:762-770. [PMID: 27920202 DOI: 10.1074/jbc.r116.760215] [Citation(s) in RCA: 183] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The mammalian brain is supplied with blood by specialized vasculature that is structurally and functionally distinct from that of the periphery. A defining feature of this vasculature is a physical blood-brain barrier (BBB). The BBB separates blood components from the brain microenvironment, regulating the entry and exit of ions, nutrients, macromolecules, and energy metabolites. Over the last two decades, physiological studies of cerebral blood flow dynamics have demonstrated that substantial intercellular communication occurs between cells of the vasculature and the neurons and glia that abut the vasculature. These findings suggest that the BBB does not function independently, but as a module within the greater context of a multicellular neurovascular unit (NVU) that includes neurons, astrocytes, pericytes, and microglia as well as the blood vessels themselves. Here, we describe the roles of these NVU components as well as how they act in concert to modify cerebrovascular function and permeability in health and in select diseases.
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Affiliation(s)
- Heather L McConnell
- From the Departments of Neurology, Pathology, Neurosurgery, and Veterans Affairs, Oregon Health & Science University, Portland, Oregon 97239-2941
| | - Cymon N Kersch
- From the Departments of Neurology, Pathology, Neurosurgery, and Veterans Affairs, Oregon Health & Science University, Portland, Oregon 97239-2941
| | - Randall L Woltjer
- From the Departments of Neurology, Pathology, Neurosurgery, and Veterans Affairs, Oregon Health & Science University, Portland, Oregon 97239-2941
| | - Edward A Neuwelt
- From the Departments of Neurology, Pathology, Neurosurgery, and Veterans Affairs, Oregon Health & Science University, Portland, Oregon 97239-2941
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113
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Kaisar MA, Sajja RK, Prasad S, Abhyankar VV, Liles T, Cucullo L. New experimental models of the blood-brain barrier for CNS drug discovery. Expert Opin Drug Discov 2016; 12:89-103. [PMID: 27782770 DOI: 10.1080/17460441.2017.1253676] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
INTRODUCTION The blood-brain barrier (BBB) is a dynamic biological interface which actively controls the passage of substances between the blood and the central nervous system (CNS). From a biological and functional standpoint, the BBB plays a crucial role in maintaining brain homeostasis inasmuch that deterioration of BBB functions are prodromal to many CNS disorders. Conversely, the BBB hinders the delivery of drugs targeting the brain to treat a variety of neurological diseases. Area covered: This article reviews recent technological improvements and innovation in the field of BBB modeling including static and dynamic cell-based platforms, microfluidic systems and the use of stem cells and 3D printing technologies. Additionally, the authors laid out a roadmap for the integration of microfluidics and stem cell biology as a holistic approach for the development of novel in vitro BBB platforms. Expert opinion: Development of effective CNS drugs has been hindered by the lack of reliable strategies to mimic the BBB and cerebrovascular impairments in vitro. Technological advancements in BBB modeling have fostered the development of highly integrative and quasi- physiological in vitro platforms to support the process of drug discovery. These advanced in vitro tools are likely to further current understanding of the cerebrovascular modulatory mechanisms.
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Affiliation(s)
- Mohammad A Kaisar
- a Department of Pharmaceutical Sciences , Texas Tech University Health Sciences Center , Amarillo , TX , USA
| | - Ravi K Sajja
- a Department of Pharmaceutical Sciences , Texas Tech University Health Sciences Center , Amarillo , TX , USA
| | - Shikha Prasad
- a Department of Pharmaceutical Sciences , Texas Tech University Health Sciences Center , Amarillo , TX , USA
| | - Vinay V Abhyankar
- c Biological Microsystems Division at The University of Texas at Arlington Research Institute , Fort Worth , TX , USA
| | - Taylor Liles
- a Department of Pharmaceutical Sciences , Texas Tech University Health Sciences Center , Amarillo , TX , USA
| | - Luca Cucullo
- a Department of Pharmaceutical Sciences , Texas Tech University Health Sciences Center , Amarillo , TX , USA.,b Center for Blood Brain Barrier Research , Texas Tech University Health Sciences Center , Amarillo , TX , USA
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114
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Wang J, Chen J, Tang Z, Li Y, Hu L, Pan J. The Effects of Copper on Brain Microvascular Endothelial Cells and Claudin Via Apoptosis and Oxidative Stress. Biol Trace Elem Res 2016; 174:132-141. [PMID: 27038183 DOI: 10.1007/s12011-016-0685-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 03/22/2016] [Indexed: 12/13/2022]
Abstract
Many neurodegenerative diseases are related to copper although the effects on brain microvascular endothelial cells (BMECs) are poorly understood. In the present study, a primary BMEC culture model was established to evaluate the effects of copper on brain microvascular endothelial cells and whether claudin-1, claudin-3, claudin-5, and claudin-12 isoforms contribute to apoptosis and intrinsic antioxidant activity. Our results showed that copper ions had dual effects on BMECs by regulating intracellular reactive oxygen species (ROS) levels. Copper levels between 30 and 120 μM could enhance viability and promote proliferation. On the other hand, copper cytotoxicity was a result of apoptosis indicating a redox-independent manner of cell death. Expression levels of claudins were also regulated by copper in a concentration-dependent manner. We identified four claudin isoforms (1, 3, 5, and 12) and showed that their expression levels were regulated as a group by copper. Antioxidant activity of BMECs was also copper regulated, and superoxide dismutase and catalase were the main contributors to BMEC antioxidant functions. Together, our results indicated that copper had dual effects on BMEC growth and intrinsic antioxidant activities played a crucial role in BMEC survival and tight junction.
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Affiliation(s)
- Jian Wang
- College of Veterinary Medicine, South China Agriculture University, WuShan Road 483, Guangzhou, 510642, China
- Key Laboratory of Comprehensive Prevention and Control for Severe Clinical Animal Diseases of Guangdong Province, Guangzhou, 510642, China
| | - Junquan Chen
- College of Veterinary Medicine, South China Agriculture University, WuShan Road 483, Guangzhou, 510642, China
- Key Laboratory of Comprehensive Prevention and Control for Severe Clinical Animal Diseases of Guangdong Province, Guangzhou, 510642, China
| | - Zhaoxin Tang
- College of Veterinary Medicine, South China Agriculture University, WuShan Road 483, Guangzhou, 510642, China.
- Key Laboratory of Comprehensive Prevention and Control for Severe Clinical Animal Diseases of Guangdong Province, Guangzhou, 510642, China.
- Key Laboratory of Biotechnology and Bioproducts Development for Animal Epidemic Prevention, Ministry of Agriculture, Zhaoqing, 526238, China.
| | - Ying Li
- College of Veterinary Medicine, South China Agriculture University, WuShan Road 483, Guangzhou, 510642, China
- Key Laboratory of Comprehensive Prevention and Control for Severe Clinical Animal Diseases of Guangdong Province, Guangzhou, 510642, China
| | - Lianmei Hu
- College of Veterinary Medicine, South China Agriculture University, WuShan Road 483, Guangzhou, 510642, China
- Key Laboratory of Comprehensive Prevention and Control for Severe Clinical Animal Diseases of Guangdong Province, Guangzhou, 510642, China
| | - Jiaqiang Pan
- College of Veterinary Medicine, South China Agriculture University, WuShan Road 483, Guangzhou, 510642, China
- Key Laboratory of Comprehensive Prevention and Control for Severe Clinical Animal Diseases of Guangdong Province, Guangzhou, 510642, China
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Chen IC, Hsiao IL, Lin HC, Wu CH, Chuang CY, Huang YJ. Influence of silver and titanium dioxide nanoparticles on in vitro blood-brain barrier permeability. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2016; 47:108-118. [PMID: 27664952 DOI: 10.1016/j.etap.2016.09.009] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 08/31/2016] [Accepted: 09/14/2016] [Indexed: 05/25/2023]
Abstract
An in vitro blood-brain barrier (BBB) model being composed of co-culture with endothelial (bEnd.3) and astrocyte-like (ALT) cells was established to evaluate the toxicity and permeability of Ag nanoparticles (AgNPs; 8nm) and TiO2 nanoparticles (TiO2NPs; 6nm and 35nm) in normal and inflammatory central nervous system. Lipopolysaccharide (LPS) was pre-treated to simulate the inflammatory responses. Both AgNPs and Ag ions can decrease transendothelial electrical resistance (TEER) value, and cause discontinuous tight junction proteins (claudin-5 and zonula occludens-1) of BBB. However, only the Ag ions induced inflammatory cytokines to release, and had less cell-to-cell permeability than AgNPs, which indicated that the toxicity of AgNPs was distinct from Ag ions. LPS itself disrupted BBB, while co-treatment with AgNPs and LPS dramatically enhanced the disruption and permeability coefficient. On the other hand, TiO2NPs exposure increased BBB penetration by size, and disrupted tight junction proteins without size dependence, and many of TiO2NPs accumulated in the endothelial cells were observed. This study provided the new insight of toxic potency of AgNPs and TiO2NPs in BBB.
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Affiliation(s)
- I-Chieh Chen
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan.
| | - I-Lun Hsiao
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan.
| | - Ho-Chen Lin
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan.
| | - Chien-Hou Wu
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan.
| | - Chun-Yu Chuang
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan.
| | - Yuh-Jeen Huang
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan.
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Banerjee J, Shi Y, Azevedo HS. In vitro blood–brain barrier models for drug research: state-of-the-art and new perspectives on reconstituting these models on artificial basement membrane platforms. Drug Discov Today 2016; 21:1367-1386. [DOI: 10.1016/j.drudis.2016.05.020] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 05/14/2016] [Accepted: 05/31/2016] [Indexed: 12/21/2022]
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Fiandra L, Mazzucchelli S, Truffi M, Bellini M, Sorrentino L, Corsi F. In Vitro Permeation of FITC-loaded Ferritins Across a Rat Blood-brain Barrier: a Model to Study the Delivery of Nanoformulated Molecules. J Vis Exp 2016. [PMID: 27583454 DOI: 10.3791/54279] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Brain microvascular endothelial cells, supported by pericytes and astrocytes endfeet, are responsible for the low permeation of large hydrosoluble drugs through the blood-brain barrier (BBB), causing difficulties for effective pharmacological therapies. In recent years, different strategies for promoting brain targeting have aimed to improve drug delivery and activity at this site, including innovative nanosystems for drug delivery across the BBB. In this context, an in vitro approach based on a simplified cellular model of the BBB provides a useful tool to investigate the effect of nanoformulations on the trans-BBB permeation of molecules. This study describes the development of a double-layer BBB, consisting of co-cultured commercially available primary rat brain microvascular endothelial cells and astrocytes. A multiparametric approach for the validation of the model, based on the measurement of the transendothelial electrical resistance and the apparent permeability of a high molecular weight dextran, is also described. As proof of concept for the employment of this BBB model to study the effect of different nanoformulations on the translocation of fluorescent molecules across the barrier, we describe the use of fluorescein isothiocyanate (FITC), loaded into ferritin nanoparticles. The ability of ferritins to improve the trans-BBB permeation of FITC was demonstrated by flux measurements and confocal microscopy analyses. The results suggest this is a useful system for validating nanosystems for delivery of drugs across the BBB.
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Affiliation(s)
- Luisa Fiandra
- Dipartimento di Scienze Biomediche e Cliniche Luigi Sacco, Università di Milano;
| | - Serena Mazzucchelli
- Dipartimento di Scienze Biomediche e Cliniche Luigi Sacco, Università di Milano
| | - Marta Truffi
- Dipartimento di Scienze Biomediche e Cliniche Luigi Sacco, Università di Milano
| | - Michela Bellini
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca
| | - Luca Sorrentino
- Dipartimento di Scienze Biomediche e Cliniche Luigi Sacco, Università di Milano
| | - Fabio Corsi
- Dipartimento di Scienze Biomediche e Cliniche Luigi Sacco, Università di Milano
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Nair M, Jayant RD, Kaushik A, Sagar V. Getting into the brain: Potential of nanotechnology in the management of NeuroAIDS. Adv Drug Deliv Rev 2016; 103:202-217. [PMID: 26944096 PMCID: PMC4935582 DOI: 10.1016/j.addr.2016.02.008] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 02/17/2016] [Accepted: 02/18/2016] [Indexed: 12/18/2022]
Abstract
In spite of significant advances in antiretroviral (ARV) therapy, the elimination of human immunodeficiency virus (HIV) reservoirs from the periphery and the central nervous system (CNS) remains a formidable task. The incapability of ARV to go across the blood-brain barrier (BBB) after systemic administration makes the brain one of the dominant HIV reservoirs. Thus, screening, monitoring, and elimination of HIV reservoirs from the brain remain a clinically daunting and key task. The practice and investigation of nanomedicine possesses potentials for therapeutics against neuroAIDS. This review highlights the advancements in nanoscience and nanotechnology to design and develop specific size therapeutic cargo for efficient navigation across BBB so as to recognize and eradicate HIV brain reservoirs. Different navigation and drug release strategies, their biocompatibility and efficacy with related challenges and future prospects are also discussed. This review would be an excellent platform to understand nano-enable multidisciplinary research to formulate efficient nanomedicine for the management of neuroAIDS.
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Key Words
- Anti-retroviral (ARV) therapy
- Blood–brain barrier (BBB)
- Bradykinin (PubChem CID: 439,201)
- CNS drug delivery
- Enfuvirtide (PubChem CID: 16,130,199), Lamivudine & Zidovudine (PubChem CID: 160,352)
- Ferrous oxide or iron (II) oxide (PubChem CID: 14,945)
- Foscarnet sodium (PubChem CID: 44,561)
- HIV monitoring
- HIV-1
- Magnetic nanoparticle
- Mannitol (PubChem CID: 6251)
- Nanotechnology
- Neopterin (PubChem CID: 4455)
- NeuroAIDS
- Pluronic-P85 (PubChem CID: 24,751)
- Saquinavir mesylate (PubChem CID: 60,934)
- Tenofovir disoproxil fumarate (PubChem CID: 6,398,764)
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Affiliation(s)
- Madhavan Nair
- Center for Personalized Nanomedicine, Institute of NeuroImmune Pharmacology, Department of Immunology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA.
| | - Rahul Dev Jayant
- Center for Personalized Nanomedicine, Institute of NeuroImmune Pharmacology, Department of Immunology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA.
| | - Ajeet Kaushik
- Center for Personalized Nanomedicine, Institute of NeuroImmune Pharmacology, Department of Immunology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA
| | - Vidya Sagar
- Center for Personalized Nanomedicine, Institute of NeuroImmune Pharmacology, Department of Immunology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA
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Shea A, Harish V, Afzal Z, Chijioke J, Kedir H, Dusmatova S, Roy A, Ramalinga M, Harris B, Blancato J, Verma M, Kumar D. MicroRNAs in glioblastoma multiforme pathogenesis and therapeutics. Cancer Med 2016; 5:1917-46. [PMID: 27282910 PMCID: PMC4971921 DOI: 10.1002/cam4.775] [Citation(s) in RCA: 140] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 04/05/2016] [Accepted: 04/14/2016] [Indexed: 12/13/2022] Open
Abstract
Glioblastoma multiforme (GBM) is the most common and lethal cancer of the adult brain, remaining incurable with a median survival time of only 15 months. In an effort to identify new targets for GBM diagnostics and therapeutics, recent studies have focused on molecular phenotyping of GBM subtypes. This has resulted in mounting interest in microRNAs (miRNAs) due to their regulatory capacities in both normal development and in pathological conditions such as cancer. miRNAs have a wide range of targets, allowing them to modulate many pathways critical to cancer progression, including proliferation, cell death, metastasis, angiogenesis, and drug resistance. This review explores our current understanding of miRNAs that are differentially modulated and pathologically involved in GBM as well as the current state of miRNA-based therapeutics. As the role of miRNAs in GBM becomes more well understood and novel delivery methods are developed and optimized, miRNA-based therapies could provide a critical step forward in cancer treatment.
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Affiliation(s)
- Amanda Shea
- Division of Science and MathematicsCancer Research LaboratoryUniversity of the District of ColumbiaWashingtonDistrict of Columbia20008
| | | | - Zainab Afzal
- Division of Science and MathematicsCancer Research LaboratoryUniversity of the District of ColumbiaWashingtonDistrict of Columbia20008
| | - Juliet Chijioke
- Division of Science and MathematicsCancer Research LaboratoryUniversity of the District of ColumbiaWashingtonDistrict of Columbia20008
| | - Habib Kedir
- Division of Science and MathematicsCancer Research LaboratoryUniversity of the District of ColumbiaWashingtonDistrict of Columbia20008
| | - Shahnoza Dusmatova
- Division of Science and MathematicsCancer Research LaboratoryUniversity of the District of ColumbiaWashingtonDistrict of Columbia20008
| | - Arpita Roy
- Division of Science and MathematicsCancer Research LaboratoryUniversity of the District of ColumbiaWashingtonDistrict of Columbia20008
| | - Malathi Ramalinga
- Division of Science and MathematicsCancer Research LaboratoryUniversity of the District of ColumbiaWashingtonDistrict of Columbia20008
| | - Brent Harris
- Department of Neurology and PathologyGeorgetown UniversityWashingtonDistrict of Columbia20057
| | - Jan Blancato
- Lombardi Comprehensive Cancer CenterGeorgetown UniversityWashingtonDistrict of Columbia20057
| | - Mukesh Verma
- Division of Cancer Control and Population SciencesNational Cancer Institute (NCI)National Institutes of Health (NIH)RockvilleMaryland20850
| | - Deepak Kumar
- Division of Science and MathematicsCancer Research LaboratoryUniversity of the District of ColumbiaWashingtonDistrict of Columbia20008
- Lombardi Comprehensive Cancer CenterGeorgetown UniversityWashingtonDistrict of Columbia20057
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120
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Aparicio-Blanco J, Martín-Sabroso C, Torres-Suárez AI. In vitro screening of nanomedicines through the blood brain barrier: A critical review. Biomaterials 2016; 103:229-255. [PMID: 27392291 DOI: 10.1016/j.biomaterials.2016.06.051] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 06/14/2016] [Accepted: 06/20/2016] [Indexed: 12/16/2022]
Abstract
The blood-brain barrier accounts for the high attrition rate of the treatments of most brain disorders, which therefore remain one of the greatest health-care challenges of the twenty first century. Against this background of hindrance to brain delivery, nanomedicine takes advantage of the assembly at the nanoscale of available biomaterials to provide a delivery platform with potential to raising brain levels of either imaging or therapeutic agents. Nevertheless, to prevent later failure due to ineffective drug levels at the target site, researchers have been endeavoring to develop a battery of in vitro screening procedures that can predict earlier in the drug discovery process the ability of these cutting-edge drug delivery platforms to cross the blood-brain barrier for biomedical purposes. This review provides an in-depth analysis of the currently available in vitro blood-brain barrier models (both cell-based and non-cell-based) with the focus on their suitability for understanding the biological brain distribution of forthcoming nanomedicines. The relationship between experimental factors and underlying physiological assumptions that would ultimately lead to a more predictive capacity of their in vivo performance, and those methods already assayed for the evaluation of the brain distribution of nanomedicines are comprehensively discussed.
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Affiliation(s)
- Juan Aparicio-Blanco
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Complutense University, 28040, Madrid, Spain
| | - Cristina Martín-Sabroso
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Complutense University, 28040, Madrid, Spain
| | - Ana-Isabel Torres-Suárez
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Complutense University, 28040, Madrid, Spain; University Institute of Industrial Pharmacy, Complutense University, 28040, Madrid, Spain.
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121
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Patel R, Alahmad AJ. Growth-factor reduced Matrigel source influences stem cell derived brain microvascular endothelial cell barrier properties. Fluids Barriers CNS 2016; 13:6. [PMID: 27068644 PMCID: PMC4828815 DOI: 10.1186/s12987-016-0030-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 03/23/2016] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Patient-derived induced pluripotent stem cells (iPSCs) are an innovative source as an in vitro model for neurological diseases. Recent studies have demonstrated the differentiation of brain microvascular endothelial cells (BMECs) from various stem cell sources, including iPSC lines. However, the impact of the culturing conditions used to maintain such stem cell pluripotency on their ability to differentiate into BMECs remains undocumented. In this study, we investigated the effect of different sources of Matrigel and stem cell maintenance medium on BMEC differentiation efficiency. METHODS The IMR90-c4 iPSC line was maintained on mTeSR1 or in essential-8 (E-8) medium on growth factor-reduced (GFR) Matrigel from three different manufacturers. Cells were differentiated into BMECs following published protocols. The phenotype of BMEC monolayers was assessed by immunocytochemistry. Barrier function was assessed by transendothelial electrical resistance (TEER) and permeability to sodium fluorescein, whereas the presence of drug efflux pumps was assessed by uptake assay using fluorescent substrates. RESULTS Stem cell maintenance medium had little effect on the yield and barrier phenotype of IMR90-derived BMECs. The source of GFR-Matrigel used for the differentiation process significantly impacted the ability of IMR90-derived BMECs to form tight monolayers, as measured by TEER and fluorescein permeability. However, the Matrigel source had minimal effect on BMEC phenotype and drug efflux pump activity. CONCLUSION This study supports the ability to differentiate BMECs from iPSCs grown in mTeSR1 or E-8 medium and also suggests that the origin of GFR-Matrigel has a marked inpact on BMEC barrier properties.
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Affiliation(s)
- Ronak Patel
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, 1300 South Coulter Street, Amarillo, TX, 79106, USA
| | - Abraham J Alahmad
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, 1300 South Coulter Street, Amarillo, TX, 79106, USA.
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Nyúl-Tóth Á, Suciu M, Molnár J, Fazakas C, Haskó J, Herman H, Farkas AE, Kaszaki J, Hermenean A, Wilhelm I, Krizbai IA. Differences in the molecular structure of the blood-brain barrier in the cerebral cortex and white matter: an in silico, in vitro, and ex vivo study. Am J Physiol Heart Circ Physiol 2016; 310:H1702-14. [PMID: 27059078 DOI: 10.1152/ajpheart.00774.2015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 03/27/2016] [Indexed: 11/22/2022]
Abstract
The blood-brain barrier (BBB) is the main interface controlling molecular and cellular traffic between the central nervous system (CNS) and the periphery. It consists of cerebral endothelial cells (CECs) interconnected by continuous tight junctions, and closely associated pericytes and astrocytes. Different parts of the CNS have diverse functions and structures and may be subject of different pathologies, in which the BBB is actively involved. It is largely unknown, however, what are the cellular and molecular differences of the BBB in different regions of the brain. Using in silico, in vitro, and ex vivo techniques we compared the expression of BBB-associated genes and proteins (i.e., markers of CECs, brain pericytes, and astrocytes) in the cortical grey matter and white matter. In silico human database analysis (obtained from recalculated data of the Allen Brain Atlas), qPCR, Western blot, and immunofluorescence studies on porcine and mouse brain tissue indicated an increased expression of glial fibrillary acidic protein in astrocytes in the white matter compared with the grey matter. We have also found increased expression of genes of the junctional complex of CECs (occludin, claudin-5, and α-catenin) in the white matter compared with the cerebral cortex. Accordingly, occludin, claudin-5, and α-catenin proteins showed increased expression in CECs of the white matter compared with endothelial cells of the cortical grey matter. In parallel, barrier properties of white matter CECs were superior as well. These differences might be important in the pathogenesis of diseases differently affecting distinct regions of the brain.
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Affiliation(s)
- Ádám Nyúl-Tóth
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Maria Suciu
- Institute of Life Sciences, Vasile Goldis Western University of Arad, Arad, Romania; and
| | - Judit Molnár
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Csilla Fazakas
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - János Haskó
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Hildegard Herman
- Institute of Life Sciences, Vasile Goldis Western University of Arad, Arad, Romania; and
| | - Attila E Farkas
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - József Kaszaki
- Institute of Surgical Research, University of Szeged, Szeged, Hungary
| | - Anca Hermenean
- Institute of Life Sciences, Vasile Goldis Western University of Arad, Arad, Romania; and
| | - Imola Wilhelm
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - István A Krizbai
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary; Institute of Life Sciences, Vasile Goldis Western University of Arad, Arad, Romania; and
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Gomes MJ, Dreier J, Brewer J, Martins S, Brandl M, Sarmento B. A new approach for a blood-brain barrier model based on phospholipid vesicles: Membrane development and siRNA-loaded nanoparticles permeability. J Memb Sci 2016. [DOI: 10.1016/j.memsci.2016.01.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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124
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Saunders NR, Habgood MD, Møllgård K, Dziegielewska KM. The biological significance of brain barrier mechanisms: help or hindrance in drug delivery to the central nervous system? F1000Res 2016; 5. [PMID: 26998242 PMCID: PMC4786902 DOI: 10.12688/f1000research.7378.1] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/04/2016] [Indexed: 12/15/2022] Open
Abstract
Barrier mechanisms in the brain are important for its normal functioning and development. Stability of the brain's internal environment, particularly with respect to its ionic composition, is a prerequisite for the fundamental basis of its function, namely transmission of nerve impulses. In addition, the appropriate and controlled supply of a wide range of nutrients such as glucose, amino acids, monocarboxylates, and vitamins is also essential for normal development and function. These are all cellular functions across the interfaces that separate the brain from the rest of the internal environment of the body. An essential morphological component of all but one of the barriers is the presence of specialized intercellular tight junctions between the cells comprising the interface: endothelial cells in the blood-brain barrier itself, cells of the arachnoid membrane, choroid plexus epithelial cells, and tanycytes (specialized glial cells) in the circumventricular organs. In the ependyma lining the cerebral ventricles in the adult brain, the cells are joined by gap junctions, which are not restrictive for intercellular movement of molecules. But in the developing brain, the forerunners of these cells form the neuroepithelium, which restricts exchange of all but the smallest molecules between cerebrospinal fluid and brain interstitial fluid because of the presence of strap junctions between the cells. The intercellular junctions in all these interfaces are the physical basis for their barrier properties. In the blood-brain barrier proper, this is combined with a paucity of vesicular transport that is a characteristic of other vascular beds. Without such a diffusional restrain, the cellular transport mechanisms in the barrier interfaces would be ineffective. Superimposed on these physical structures are physiological mechanisms as the cells of the interfaces contain various metabolic transporters and efflux pumps, often ATP-binding cassette (ABC) transporters, that provide an important component of the barrier functions by either preventing entry of or expelling numerous molecules including toxins, drugs, and other xenobiotics. In this review, we summarize these influx and efflux mechanisms in normal developing and adult brain, as well as indicating their likely involvement in a wide range of neuropathologies. There have been extensive attempts to overcome the barrier mechanisms that prevent the entry of many drugs of therapeutic potential into the brain. We outline those that have been tried and discuss why they may so far have been largely unsuccessful. Currently, a promising approach appears to be focal, reversible disruption of the blood-brain barrier using focused ultrasound, but more work is required to evaluate the method before it can be tried in patients. Overall, our view is that much more fundamental knowledge of barrier mechanisms and development of new experimental methods will be required before drug targeting to the brain is likely to be a successful endeavor. In addition, such studies, if applied to brain pathologies such as stroke, trauma, or multiple sclerosis, will aid in defining the contribution of brain barrier pathology to these conditions, either causative or secondary.
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Affiliation(s)
- Norman R Saunders
- Department of Pharmacology & Therapeutics, University of Melbourne, Parkville, Victoria, Australia
| | - Mark D Habgood
- Department of Pharmacology & Therapeutics, University of Melbourne, Parkville, Victoria, Australia
| | - Kjeld Møllgård
- Institute of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
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Wilhelm I, Nyúl-Tóth Á, Suciu M, Hermenean A, Krizbai IA. Heterogeneity of the blood-brain barrier. Tissue Barriers 2016; 4:e1143544. [PMID: 27141424 DOI: 10.1080/21688370.2016.1143544] [Citation(s) in RCA: 150] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 01/08/2016] [Accepted: 01/12/2016] [Indexed: 01/08/2023] Open
Abstract
The brain microvascular network is comprised of capillaries, arterioles and venules, all of which retain - although to a different extent - blood-brain barrier (BBB) properties. Capillaries constitute the largest and tightest microvasculature. In contrast, venules have a looser junctional arrangement, while arterioles have a lower expression of P-gp. Development and maintenance of the BBB depends on the interaction of cerebral endothelial cells with pericytes and astrocytes, which are all heterogeneous in different regions of the central nervous system. At the level of circumventricular organs microvessels are permeable, containing fenestrations and discontinuous tight junctions. In addition, the blood-spinal cord barrier - where the number of pericytes is lower and expression of junctional proteins is reduced - is also more permeable than the BBB. However, much less is known about the cellular, molecular and functional differences among other regions of the brain. This review summarizes our current knowledge on the heterogeneity of the brain microvasculature.
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Affiliation(s)
- Imola Wilhelm
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences ; Szeged, Hungary
| | - Ádám Nyúl-Tóth
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences ; Szeged, Hungary
| | - Maria Suciu
- Institute of Life Sciences, Vasile Goldis Western University of Arad ; Arad, Romania
| | - Anca Hermenean
- Institute of Life Sciences, Vasile Goldis Western University of Arad ; Arad, Romania
| | - István A Krizbai
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences; Szeged, Hungary; Institute of Life Sciences, Vasile Goldis Western University of Arad; Arad, Romania
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Glucose Transporters at the Blood-Brain Barrier: Function, Regulation and Gateways for Drug Delivery. Mol Neurobiol 2016; 54:1046-1077. [PMID: 26801191 DOI: 10.1007/s12035-015-9672-6] [Citation(s) in RCA: 201] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 12/17/2015] [Indexed: 12/31/2022]
Abstract
Glucose transporters (GLUTs) at the blood-brain barrier maintain the continuous high glucose and energy demands of the brain. They also act as therapeutic targets and provide routes of entry for drug delivery to the brain and central nervous system for treatment of neurological and neurovascular conditions and brain tumours. This article first describes the distribution, function and regulation of glucose transporters at the blood-brain barrier, the major ones being the sodium-independent facilitative transporters GLUT1 and GLUT3. Other GLUTs and sodium-dependent transporters (SGLTs) have also been identified at lower levels and under various physiological conditions. It then considers the effects on glucose transporter expression and distribution of hypoglycemia and hyperglycemia associated with diabetes and oxygen/glucose deprivation associated with cerebral ischemia. A reduction in glucose transporters at the blood-brain barrier that occurs before the onset of the main pathophysiological changes and symptoms of Alzheimer's disease is a potential causative effect in the vascular hypothesis of the disease. Mutations in glucose transporters, notably those identified in GLUT1 deficiency syndrome, and some recreational drug compounds also alter the expression and/or activity of glucose transporters at the blood-brain barrier. Approaches for drug delivery across the blood-brain barrier include the pro-drug strategy whereby drug molecules are conjugated to glucose transporter substrates or encapsulated in nano-enabled delivery systems (e.g. liposomes, micelles, nanoparticles) that are functionalised to target glucose transporters. Finally, the continuous development of blood-brain barrier in vitro models is important for studying glucose transporter function, effects of disease conditions and interactions with drugs and xenobiotics.
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Pandey PK, Sharma AK, Gupta U. Blood brain barrier: An overview on strategies in drug delivery, realistic in vitro modeling and in vivo live tracking. Tissue Barriers 2016; 4:e1129476. [PMID: 27141418 PMCID: PMC4836458 DOI: 10.1080/21688370.2015.1129476] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 12/01/2015] [Accepted: 12/04/2015] [Indexed: 12/25/2022] Open
Abstract
Blood brain barrier (BBB) is a group of astrocytes, neurons and endothelial cells, which makes restricted passage of various biological or chemical entities to the brain tissue. It gives protection to brain at one hand, but at the other hand it has very selective permeability for bio-actives and other foreign materials and is one of the major challenges for the drug delivery. Nanocarriers are promising to cross BBB utilizing alternative route of administration such as intranasal and intra-carotid drug delivery which bypasses BBB. In future more optimized drug delivery system can be achieved by compiling the best routes with the best carriers. Single photon emission tomography (SPECT) and different brain-on-a-chip in vitro models are being very reliable to study live in vivo tracking of BBB and its pathophysiology, respectively. In the current review we have tried to exploit mechanistically all these to understand and manage the various BBB disruptions in diseased condition along with crossing the hurdles occurring in drug or gene delivery across BBB.
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Affiliation(s)
- Pawan Kumar Pandey
- Department of Pharmacy; School of Chemical Sciences and Pharmacy, Central University of Rajasthan; Ajmer; Rajasthan, India
| | - Ashok Kumar Sharma
- Department of Pharmacy; School of Chemical Sciences and Pharmacy, Central University of Rajasthan; Ajmer; Rajasthan, India
| | - Umesh Gupta
- Department of Pharmacy; School of Chemical Sciences and Pharmacy, Central University of Rajasthan; Ajmer; Rajasthan, India
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Molnár J, Fazakas C, Haskó J, Sipos O, Nagy K, Nyúl-Tóth Á, Farkas AE, Végh AG, Váró G, Galajda P, Krizbai IA, Wilhelm I. Transmigration characteristics of breast cancer and melanoma cells through the brain endothelium: Role of Rac and PI3K. Cell Adh Migr 2015; 10:269-81. [PMID: 26645485 DOI: 10.1080/19336918.2015.1122156] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Brain metastases are common and devastating complications of both breast cancer and melanoma. Although mammary carcinoma brain metastases are more frequent than those originating from melanoma, this latter has the highest tropism to the brain. Using static and dynamic in vitro approaches, here we show that melanoma cells have increased adhesion to the brain endothelium in comparison to breast cancer cells. Moreover, melanoma cells can transmigrate more rapidly and in a higher number through brain endothelial monolayers than breast cancer cells. In addition, melanoma cells have increased ability to impair tight junctions of cerebral endothelial cells. We also show that inhibition of Rac or PI3K impedes adhesion of breast cancer cells and melanoma cells to the brain endothelium. In addition, inhibition of Rac or PI3K inhibits the late phase of transmigration of breast cancer cells and the early phase of transmigration of melanoma cells. On the other hand, the Rac inhibitor EHT1864 impairs the junctional integrity of the brain endothelium, while the PI3K inhibitor LY294002 has no damaging effect on interendothelial junctions. We suggest that targeting the PI3K/Akt pathway may represent a novel opportunity in preventing the formation of brain metastases of melanoma and breast cancer.
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Affiliation(s)
- Judit Molnár
- a Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences , Szeged , Hungary
| | - Csilla Fazakas
- a Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences , Szeged , Hungary
| | - János Haskó
- a Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences , Szeged , Hungary
| | - Orsolya Sipos
- a Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences , Szeged , Hungary
| | - Krisztina Nagy
- a Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences , Szeged , Hungary
| | - Ádám Nyúl-Tóth
- a Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences , Szeged , Hungary
| | - Attila E Farkas
- a Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences , Szeged , Hungary
| | - Attila G Végh
- a Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences , Szeged , Hungary
| | - György Váró
- a Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences , Szeged , Hungary
| | - Péter Galajda
- a Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences , Szeged , Hungary
| | - István A Krizbai
- a Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences , Szeged , Hungary.,b Institute of Life Sciences, Vasile Goldis Western University of Arad , Arad , Romania
| | - Imola Wilhelm
- a Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences , Szeged , Hungary
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129
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Tuning the predictive capacity of the PAMPA-BBB model. Eur J Pharm Sci 2015; 79:53-60. [PMID: 26344358 DOI: 10.1016/j.ejps.2015.08.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 08/28/2015] [Accepted: 08/29/2015] [Indexed: 11/23/2022]
Abstract
Due to its robustness and versatility, several variations of the blood-brain barrier specific parallel artificial membrane permeability assay (PAMPA-BBB) have been reported in the central nervous system (CNS) drug discovery practice. In this study, the impact of the main assay parameters on the predictive power of PAMPA-BBB was thoroughly investigated with 27, passively BBB-transported drug molecules with in vivo logBB data. The single and combined effects of the following variables were systematically studied and optimized: incubation time and temperature (4 vs. 18h, RT vs. 37°C), type of the read-out (UV-reader vs. HPLC), solvent composition (n-dodecane/n-hexane), lipid concentration (0-10w/v % PBLE), cholesterol content (0-1.66w/v %), and thickness of the lipid membrane, and the DMSO cosolvent content (5-20v/v %), respectively. Based on our results, solvent-driven and lipid-driven mechanisms of diffusion were identified in different assay conditions. Moreover, the analysis of membrane retention (MR%; the mole fraction of solute "lost" to the membrane) data obtained at various membrane compositions (volume of solvent and concentration of phospholipids) revealed the compound-specific nature of this parameter. The optimized conditions for the PAMPA-BBB were the following: 4h incubation at 37°C, detection by HPLC-DAD, iso-pH conditions (pH=7.4) with 5v/v % DMSO content in buffer solutions, and PBLE (10w/v %; without cholesterol) as membrane dissolved in the mixture of n-hexane:n-dodecane 3:1.
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A Triple Culture Model of the Blood-Brain Barrier Using Porcine Brain Endothelial cells, Astrocytes and Pericytes. PLoS One 2015; 10:e0134765. [PMID: 26241648 PMCID: PMC4524625 DOI: 10.1371/journal.pone.0134765] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 07/13/2015] [Indexed: 01/18/2023] Open
Abstract
In vitro blood-brain barrier (BBB) models based on primary brain endothelial cells (BECs) cultured as monoculture or in co-culture with primary astrocytes and pericytes are useful for studying many properties of the BBB. The BECs retain their expression of tight junction proteins and efflux transporters leading to high trans-endothelial electric resistance (TEER) and low passive paracellular permeability. The BECs, astrocytes and pericytes are often isolated from small rodents. Larger species as cows and pigs however, reveal a higher yield, are readily available and have a closer resemblance to humans, which make them favorable high-throughput sources for cellular isolation. The aim of the present study has been to determine if the preferable combination of purely porcine cells isolated from the 6 months old domestic pigs, i.e. porcine brain endothelial cells (PBECs) in co-culture with porcine astrocytes and pericytes, would compare with PBECs co-cultured with astrocytes and pericytes isolated from newborn rats with respect to TEER value and low passive permeability. The astrocytes and pericytes were grown both as contact and non-contact co-cultures as well as in triple culture to examine their effects on the PBECs for barrier formation as revealed by TEER, passive permeability, and expression patterns of tight junction proteins, efflux transporters and the transferrin receptor. This syngenic porcine in vitro BBB model is comparable to triple cultures using PBECs, rat astrocytes and rat pericytes with respect to TEER formation, low passive permeability, and expression of hallmark proteins signifying the brain endothelium (tight junction proteins claudin 5 and occludin, the efflux transporters P-glycoprotein (PgP) and breast cancer related protein (BCRP), and the transferrin receptor).
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Hovell CM, Sei YJ, Kim Y. Microengineered vascular systems for drug development. JOURNAL OF LABORATORY AUTOMATION 2015; 20:251-8. [PMID: 25424383 PMCID: PMC5663643 DOI: 10.1177/2211068214560767] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Indexed: 11/15/2022]
Abstract
Recent advances in microfabrication technologies and advanced biomaterials have allowed for the development of in vitro platforms that recapitulate more physiologically relevant cellular components and function. Microengineered vascular systems are of particular importance for the efficient assessment of drug candidates to physiological barriers lining microvessels. This review highlights advances in the development of microengineered vascular structures with an emphasis on the potential impact on drug delivery studies. Specifically, this article examines the development of models for the study of drug delivery to the central nervous system and cardiovascular system. We also discuss current challenges and future prospects of the development of microengineered vascular systems.
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Affiliation(s)
- Candice M Hovell
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Atlanta, GA, USA
| | - Yoshitaka J Sei
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Atlanta, GA, USA
| | - YongTae Kim
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Atlanta, GA, USA George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Atlanta, GA, USA Institute for Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, Atlanta, GA, USA Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
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Srinivasan B, Kolli AR, Esch MB, Abaci HE, Shuler ML, Hickman JJ. TEER measurement techniques for in vitro barrier model systems. ACTA ACUST UNITED AC 2015; 20:107-26. [PMID: 25586998 DOI: 10.1177/2211068214561025] [Citation(s) in RCA: 1216] [Impact Index Per Article: 135.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Transepithelial/transendothelial electrical resistance (TEER) is a widely accepted quantitative technique to measure the integrity of tight junction dynamics in cell culture models of endothelial and epithelial monolayers. TEER values are strong indicators of the integrity of the cellular barriers before they are evaluated for transport of drugs or chemicals. TEER measurements can be performed in real time without cell damage and generally are based on measuring ohmic resistance or measuring impedance across a wide spectrum of frequencies. The measurements for various cell types have been reported with commercially available measurement systems and also with custom-built microfluidic implementations. Some of the barrier models that have been widely characterized using TEER include the blood-brain barrier (BBB), gastrointestinal (GI) tract, and pulmonary models. Variations in these values can arise due to factors such as temperature, medium formulation, and passage number of cells. The aim of this article is to review the different TEER measurement techniques and analyze their strengths and weaknesses, determine the significance of TEER in drug toxicity studies, examine the various in vitro models and microfluidic organs-on-chips implementations using TEER measurements in some widely studied barrier models (BBB, GI tract, and pulmonary), and discuss the various factors that can affect TEER measurements.
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Affiliation(s)
- Balaji Srinivasan
- NanoScience Technology Center, University of Central Florida, Orlando, FL, USA
| | - Aditya Reddy Kolli
- NanoScience Technology Center, University of Central Florida, Orlando, FL, USA
| | | | | | | | - James J Hickman
- NanoScience Technology Center, University of Central Florida, Orlando, FL, USA Biomolecular Science Center, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, USA
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Bauer HC, Krizbai IA, Bauer H, Traweger A. "You Shall Not Pass"-tight junctions of the blood brain barrier. Front Neurosci 2014; 8:392. [PMID: 25520612 PMCID: PMC4253952 DOI: 10.3389/fnins.2014.00392] [Citation(s) in RCA: 165] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 11/14/2014] [Indexed: 12/31/2022] Open
Abstract
The structure and function of the barrier layers restricting the free diffusion of substances between the central nervous system (brain and spinal cord) and the systemic circulation is of great medical interest as various pathological conditions often lead to their impairment. Excessive leakage of blood-borne molecules into the parenchyma and the concomitant fluctuations in the microenvironment following a transient breakdown of the blood-brain barrier (BBB) during ischemic/hypoxic conditions or because of an autoimmune disease are detrimental to the physiological functioning of nervous tissue. On the other hand, the treatment of neurological disorders is often hampered as only minimal amounts of therapeutic agents are able to penetrate a fully functional BBB or blood cerebrospinal fluid barrier. An in-depth understanding of the molecular machinery governing the establishment and maintenance of these barriers is necessary to develop rational strategies allowing a controlled delivery of appropriate drugs to the CNS. At the basis of such tissue barriers are intimate cell-cell contacts (zonulae occludentes, tight junctions) which are present in all polarized epithelia and endothelia. By creating a paracellular diffusion constraint TJs enable the vectorial transport across cell monolayers. More recent findings indicate that functional barriers are already established during development, protecting the fetal brain. As an understanding of the biogenesis of TJs might reveal the underlying mechanisms of barrier formation during ontogenic development numerous in vitro systems have been developed to study the assembly and disassembly of TJs. In addition, monitoring the stage-specific expression of TJ-associated proteins during development has brought much insight into the “developmental tightening” of tissue barriers. Over the last two decades a detailed molecular map of transmembrane and cytoplasmic TJ-proteins has been identified. These proteins not only form a cell-cell adhesion structure, but integrate various signaling pathways, thereby directly or indirectly impacting upon processes such as cell-cell adhesion, cytoskeletal rearrangement, and transcriptional control. This review will provide a brief overview on the establishment of the BBB during embryonic development in mammals and a detailed description of the ultrastructure, biogenesis, and molecular composition of epithelial and endothelial TJs will be given.
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Affiliation(s)
- Hans-Christian Bauer
- Institute of Tendon and Bone Regeneration, Paracelsus Medical University - Spinal Cord Injury and Tissue Regeneration Center Salzburg Salzburg, Austria ; Department of Traumatology and Sports Injuries, Paracelsus Medical University Salzburg, Austria ; Austrian Cluster for Tissue Regeneration Vienna, Austria
| | - István A Krizbai
- Biological Research Centre, Institute of Biophysics, Hungarian Academy of Sciences Szeged, Hungary ; Institute of Life Sciences, Vasile Goldis Western University of Arad Arad, Romania
| | - Hannelore Bauer
- Department of Organismic Biology, University of Salzburg Salzburg, Austria
| | - Andreas Traweger
- Institute of Tendon and Bone Regeneration, Paracelsus Medical University - Spinal Cord Injury and Tissue Regeneration Center Salzburg Salzburg, Austria ; Austrian Cluster for Tissue Regeneration Vienna, Austria
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134
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CB2 receptor activation inhibits melanoma cell transmigration through the blood-brain barrier. Int J Mol Sci 2014; 15:8063-74. [PMID: 24815068 PMCID: PMC4057719 DOI: 10.3390/ijms15058063] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 04/04/2014] [Accepted: 04/22/2014] [Indexed: 02/07/2023] Open
Abstract
During parenchymal brain metastasis formation tumor cells need to migrate through cerebral endothelial cells, which form the morphological basis of the blood-brain barrier (BBB). The mechanisms of extravasation of tumor cells are highly uncharacterized, but in some aspects recapitulate the diapedesis of leukocytes. Extravasation of leukocytes through the BBB is decreased by the activation of type 2 cannabinoid receptors (CB2); therefore, in the present study we sought to investigate the role of CB2 receptors in the interaction of melanoma cells with the brain endothelium. First, we identified the presence of CB1, CB2(A), GPR18 (transcriptional variant 1) and GPR55 receptors in brain endothelial cells, while melanoma cells expressed CB1, CB2(A), GPR18 (transcriptional variants 1 and 2), GPR55 and GPR119. We observed that activation of CB2 receptors with JWH-133 reduced the adhesion of melanoma cells to the layer of brain endothelial cells. JWH-133 decreased the transendothelial migration rate of melanoma cells as well. Our results suggest that changes induced in endothelial cells are critical in the mediation of the effect of CB2 agonists. Our data identify CB2 as a potential target in reducing the number of brain metastastes originating from melanoma.
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