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Smith FM, Kosman DJ. Loss of filamentous actin, tight junction protein expression, and paracellular barrier integrity in frataxin-deficient human brain microvascular endothelial cells-implications for blood-brain barrier physiology in Friedreich's ataxia. Front Mol Biosci 2024; 10:1299201. [PMID: 38274097 PMCID: PMC10808331 DOI: 10.3389/fmolb.2023.1299201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 12/22/2023] [Indexed: 01/27/2024] Open
Abstract
Introduction: Friedreich's Ataxia (FRDA) is the most prevalent inherited ataxia. FRDA results from loss of Frataxin (FXN), an essential mitochondrial iron trafficking protein. FRDA starts with an early burst of neurodegeneration of the dorsal root ganglion and cerebellar dentate nuclei, followed by progressive brain iron accumulation in the latter. End stage disease includes cardiac fibrosis that contributes to hypertrophic cardiomyopathy. The microvasculature plays an essential barrier role in both brain and heart homeostasis, thus an investigation of this tissue system in FRDA is essential to the delineation of the cellular dysfunction in this genetic disorder. Previous reports have identified cytoskeletal alterations in non-barrier forming FRDA cell models, but physiological consequences are limited. Methods: We investigated brain microvascular endothelial cell integrity in FRDA in a model of the blood-brain barrier (BBB). We have knocked down FXN in immortalized human brain microvascular endothelial cells (hBMVEC), which compose the microcapillaries of the BBB, by using shRNA. We confirmed known cellular pathophysiologies of FXN-knockdown including decreased energy metabolism, markers of oxidative stress, and increased cell size. Results: We investigated cytoskeletal architecture, identifying decreased filamentous actin and Occludin and Claudin-5 tight junction protein expression in shFXN hBMVECs. This was consistent with decreased transendothelial electrical resistance (TEER) and increased paracellular tracer flux during early barrier formation. shFXN hBMVEC start with only 67% barrier integrity of the controls, and flux a paracellular tracer at 800% of physiological levels. Discussion: We identified that insufficient FXN levels in the hBMVEC BBB model causes changes in cytoskeletal architecture and tight junction protein abundance, co-incident with increased barrier permeability. Changes in the integrity of the BBB may be related to patient brain iron accumulation, neuroinflammation, neurodegeneration, and stroke. Furthermore, our findings implicate other barrier cells, e.g., the cardiac microvasculature, loci of disease pathology in FRDA.
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Affiliation(s)
- Frances M. Smith
- Jacobs School of Medicine and Biomedical Sciences, Department of Biochemistry, The State University of New York at Buffalo, Buffalo, NY, United States
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2
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Ledwig V, Reichl S. Isolation and Cultivation of Porcine Endothelial Cells, Pericytes and Astrocytes to Develop an In Vitro Blood-Brain Barrier Model for Drug Permeation Testing. Pharmaceutics 2023; 15:1688. [PMID: 37376136 DOI: 10.3390/pharmaceutics15061688] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 05/25/2023] [Accepted: 06/02/2023] [Indexed: 06/29/2023] Open
Abstract
The blood-brain barrier (BBB) is the bottleneck in the development of new drugs to reach the brain. Due to the BBB, toxic substances cannot enter the brain, but promising drug candidates also pass the BBB poorly. Suitable in vitro BBB models are therefore of particular importance during the preclinical development process, as they can not only reduce animal testing but also enable new drugs to be developed more quickly. The aim of this study was to isolate cerebral endothelial cells, pericytes, and astrocytes from the porcine brain to produce a primary model of the BBB. Additionally, as primary cells are well suited by their properties but the isolation is complex and better reproducibility with immortalized cells must be ensured, there is a high demand for immortalized cells with suitable properties for use as a BBB model. Thus, isolated primary cells can also serve as the basis for a suitable immortalization technique to generate new cell lines. In this work, cerebral endothelial cells, pericytes, and astrocytes were successfully isolated and expanded using a mechanical/enzymatic method. Furthermore, in a triple coculture model, the cells showed a significant increase in barrier integrity compared with endothelial cell monoculture, as determined by transendothelial electrical resistance measurement and permeation studies using sodium fluorescein. The results demonstrate the opportunity to obtain all three cell types significantly involved in BBB formation from one species, thus providing a suitable tool for testing the permeation properties of new drug candidates. In addition, the protocols are a promising starting point to generate new cell lines of BBB-forming cells as a novel approach for BBB in vitro models.
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Affiliation(s)
- Verena Ledwig
- Center of Pharmaceutical Engineering (PVZ), Technische Universität Braunschweig, Franz-Liszt-Straße 35A, 38106 Braunschweig, Germany
- Institute of Pharmaceutical Technology and Biopharmaceutics, Technische Universität Braunschweig, Mendelssohnstraße 1, 38106 Braunschweig, Germany
| | - Stephan Reichl
- Center of Pharmaceutical Engineering (PVZ), Technische Universität Braunschweig, Franz-Liszt-Straße 35A, 38106 Braunschweig, Germany
- Institute of Pharmaceutical Technology and Biopharmaceutics, Technische Universität Braunschweig, Mendelssohnstraße 1, 38106 Braunschweig, Germany
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3
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Kincses A, Vigh JP, Petrovszki D, Valkai S, Kocsis AE, Walter FR, Lin HY, Jan JS, Deli MA, Dér A. The Use of Sensors in Blood-Brain Barrier-on-a-Chip Devices: Current Practice and Future Directions. Biosensors (Basel) 2023; 13:bios13030357. [PMID: 36979569 PMCID: PMC10046513 DOI: 10.3390/bios13030357] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 02/27/2023] [Accepted: 03/02/2023] [Indexed: 06/01/2023]
Abstract
The application of lab-on-a-chip technologies in in vitro cell culturing swiftly resulted in improved models of human organs compared to static culture insert-based ones. These chip devices provide controlled cell culture environments to mimic physiological functions and properties. Models of the blood-brain barrier (BBB) especially profited from this advanced technological approach. The BBB represents the tightest endothelial barrier within the vasculature with high electric resistance and low passive permeability, providing a controlled interface between the circulation and the brain. The multi-cell type dynamic BBB-on-chip models are in demand in several fields as alternatives to expensive animal studies or static culture inserts methods. Their combination with integrated biosensors provides real-time and noninvasive monitoring of the integrity of the BBB and of the presence and concentration of agents contributing to the physiological and metabolic functions and pathologies. In this review, we describe built-in sensors to characterize BBB models via quasi-direct current and electrical impedance measurements, as well as the different types of biosensors for the detection of metabolites, drugs, or toxic agents. We also give an outlook on the future of the field, with potential combinations of existing methods and possible improvements of current techniques.
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Affiliation(s)
- András Kincses
- Institute of Biophysics, Biological Research Centre, H-6726 Szeged, Hungary; (A.K.); (J.P.V.); (D.P.); (S.V.); (A.E.K.); (F.R.W.)
| | - Judit P. Vigh
- Institute of Biophysics, Biological Research Centre, H-6726 Szeged, Hungary; (A.K.); (J.P.V.); (D.P.); (S.V.); (A.E.K.); (F.R.W.)
- Doctoral School of Biology, University of Szeged, H-6720 Szeged, Hungary
| | - Dániel Petrovszki
- Institute of Biophysics, Biological Research Centre, H-6726 Szeged, Hungary; (A.K.); (J.P.V.); (D.P.); (S.V.); (A.E.K.); (F.R.W.)
- Doctoral School of Multidisciplinary Medical Sciences, University of Szeged, H-6720 Szeged, Hungary
| | - Sándor Valkai
- Institute of Biophysics, Biological Research Centre, H-6726 Szeged, Hungary; (A.K.); (J.P.V.); (D.P.); (S.V.); (A.E.K.); (F.R.W.)
| | - Anna E. Kocsis
- Institute of Biophysics, Biological Research Centre, H-6726 Szeged, Hungary; (A.K.); (J.P.V.); (D.P.); (S.V.); (A.E.K.); (F.R.W.)
| | - Fruzsina R. Walter
- Institute of Biophysics, Biological Research Centre, H-6726 Szeged, Hungary; (A.K.); (J.P.V.); (D.P.); (S.V.); (A.E.K.); (F.R.W.)
| | - Hung-Yin Lin
- Department of Chemical and Materials Engineering, National University of Kaohsiung, Kaohsiung 81148, Taiwan;
| | - Jeng-Shiung Jan
- Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan;
| | - Mária A. Deli
- Institute of Biophysics, Biological Research Centre, H-6726 Szeged, Hungary; (A.K.); (J.P.V.); (D.P.); (S.V.); (A.E.K.); (F.R.W.)
| | - András Dér
- Institute of Biophysics, Biological Research Centre, H-6726 Szeged, Hungary; (A.K.); (J.P.V.); (D.P.); (S.V.); (A.E.K.); (F.R.W.)
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4
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Jamieson JJ, Lin Y, Malloy N, Soto D, Searson PC, Gerecht S. Hypoxia-induced blood-brain barrier dysfunction is prevented by pericyte-conditioned media via attenuated actomyosin contractility and claudin-5 stabilization. FASEB J 2022; 36:e22331. [PMID: 35476363 PMCID: PMC9060394 DOI: 10.1096/fj.202200010rr] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 04/12/2022] [Accepted: 04/15/2022] [Indexed: 11/11/2022]
Abstract
The blood-brain barrier (BBB) regulates molecular and cellular entry from the cerebrovasculature into the surrounding brain parenchyma. Many diseases of the brain are associated with dysfunction of the BBB, where hypoxia is a common stressor. However, the contribution of hypoxia to BBB dysfunction is challenging to study due to the complexity of the brain microenvironment. In this study, we used a BBB model with brain microvascular endothelial cells and pericytes differentiated from iPSCs to investigate the effect of hypoxia on barrier function. We found that hypoxia-induced barrier dysfunction is dependent upon increased actomyosin contractility and is associated with increased fibronectin fibrillogenesis. We propose a role for actomyosin contractility in mediating hypoxia-induced barrier dysfunction through modulation of junctional claudin-5. Our findings suggest pericytes may protect brain microvascular endothelial cells from hypoxic stresses and that pericyte-derived factors could be candidates for treatment of pathological barrier-forming tissues.
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Affiliation(s)
- John J Jamieson
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, USA.,Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, Maryland, USA
| | - YingYu Lin
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, USA.,Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Nicholas Malloy
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Daniel Soto
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Peter C Searson
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, Maryland, USA.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, USA.,Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Sharon Gerecht
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, USA.,Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, Maryland, USA.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, USA.,Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland, USA.,Department of Biomedical Engineering, Duke University, Duke, North Carolina, USA
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5
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Chalimeswamy A, Thanuja MY, Ranganath SH, Pandya K, Kompella UB, Srinivas SP. Oxidative Stress Induces a Breakdown of the Cytoskeleton and Tight Junctions of the Corneal Endothelial Cells. J Ocul Pharmacol Ther 2021; 38:74-84. [PMID: 34818079 DOI: 10.1089/jop.2021.0037] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Purpose: To investigate the impact of oxidative stress, which is a hallmark of Fuchs dystrophy, on the barrier function of the corneal endothelial cells. Methods: Experiments were carried out with cultured bovine and porcine corneal endothelial cells. For oxidative stress, cells were supplemented with riboflavin (Rf) and exposed to UV-A (15-30 min) to induce Type-1 photochemical reactions that release H2O2. The effect of the stress on the barrier function was assayed by transendothelial electrical resistance (TER) measurement. In addition, the associated changes in the organization of the microtubules, perijunctional actomyosin ring (PAMR), and ZO-1 were evaluated by immunocytochemistry, which was also repeated after direct exposure to H2O2 (100 μM, 1 h). Results: Exposure to H2O2 led to the disassembly of microtubules and the destruction of PAMR. In parallel, the contiguous locus of ZO-1 was disrupted, marking a loss of barrier integrity. Accordingly, a sustained loss in TER was induced when cells in the Rf-supplemented medium were exposed to UV-A. However, the addition of catalase (7,000 U/mL) to rapidly decompose H2O2 limited the loss in TER. Furthermore, the adverse effects on microtubules, PAMR, and ZO-1 were suppressed by including catalase, ascorbic acid (1 mM; 30 min), or pretreatment with p38 MAP kinase inhibitor (SB-203580; 10 μM, 1 h). Conclusions: Acute oxidative stress induces microtubule disassembly by a p38 MAP kinase-dependent mechanism, leading to the destruction of PAMR and loss of barrier function. The response to oxidative stress is reminiscent of the (TNF-α)-induced breakdown of barrier failure in the corneal endothelium.
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Affiliation(s)
- Anupama Chalimeswamy
- Department of Biotechnology, Siddaganga Institute of Technology, Tumakuru, India.,Bio-INvENT Lab, Department of Chemical Engineering, Siddaganga Institute of Technology, Tumakuru, India
| | | | - Sudhir H Ranganath
- Bio-INvENT Lab, Department of Chemical Engineering, Siddaganga Institute of Technology, Tumakuru, India
| | - Kaveet Pandya
- School of Optometry, Indiana University, Bloomington, Indiana, USA
| | - Uday B Kompella
- Pharmaceutical Sciences, University of Colorado, Aurora, Colorado, USA
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Watanabe D, Nakagawa S, Morofuji Y, Tóth AE, Vastag M, Aruga J, Niwa M, Deli MA. Characterization of a Primate Blood-Brain Barrier Co-Culture Model Prepared from Primary Brain Endothelial Cells, Pericytes and Astrocytes. Pharmaceutics 2021; 13:pharmaceutics13091484. [PMID: 34575559 PMCID: PMC8470770 DOI: 10.3390/pharmaceutics13091484] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/09/2021] [Accepted: 09/13/2021] [Indexed: 01/25/2023] Open
Abstract
Culture models of the blood-brain barrier (BBB) are important research tools. Their role in the preclinical phase of drug development to estimate the permeability for potential neuropharmaceuticals is especially relevant. Since species differences in BBB transport systems exist, primate models are considered as predictive for drug transport to brain in humans. Based on our previous expertise we have developed and characterized a non-human primate co-culture BBB model using primary cultures of monkey brain endothelial cells, rat brain pericytes, and rat astrocytes. Monkey brain endothelial cells in the presence of both pericytes and astrocytes (EPA model) expressed enhanced barrier properties and increased levels of tight junction proteins occludin, claudin-5, and ZO-1. Co-culture conditions also elevated the expression of key BBB influx and efflux transporters, including glucose transporter-1, MFSD2A, ABCB1, and ABCG2. The correlation between the endothelial permeability coefficients of 10 well known drugs was higher (R2 = 0.8788) when the monkey and rat BBB culture models were compared than when the monkey culture model was compared to mouse in vivo data (R2 = 0.6619), hinting at transporter differences. The applicability of the new non-human primate model in drug discovery has been proven in several studies.
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Affiliation(s)
- Daisuke Watanabe
- Department of Medical Pharmacology, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; (D.W.); (J.A.)
- BBB Laboratory, PharmaCo-Cell Co., Ltd., Nagasaki 852-8135, Japan;
| | - Shinsuke Nakagawa
- Department of Pharmaceutical Care and Health Sciences, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan;
| | - Yoichi Morofuji
- Department of Neurosurgery, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8501, Japan;
| | - Andrea E. Tóth
- Institute of Biophysics, Biological Research Centre, Temesvári krt. 62, H-6726 Szeged, Hungary;
| | - Monika Vastag
- In Vitro Metabolism Research, Division of Pharmacology and Drug Safety Research, Gedeon Richter Plc., Gyömrői út 19-21, H-1103 Budapest, Hungary;
| | - Jun Aruga
- Department of Medical Pharmacology, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; (D.W.); (J.A.)
| | - Masami Niwa
- BBB Laboratory, PharmaCo-Cell Co., Ltd., Nagasaki 852-8135, Japan;
| | - Mária A. Deli
- Institute of Biophysics, Biological Research Centre, Temesvári krt. 62, H-6726 Szeged, Hungary;
- Correspondence:
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7
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Khan A, Ni W, Lopez-Giraldez F, Kluger MS, Pober JS, Pierce RW. Tumor necrosis factor-induced ArhGEF10 selectively activates RhoB contributing to human microvascular endothelial cell tight junction disruption. FASEB J 2021; 35:e21627. [PMID: 33948992 DOI: 10.1096/fj.202002783rr] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 04/07/2021] [Accepted: 04/13/2021] [Indexed: 12/31/2022]
Abstract
Capillary endothelial cells (ECs) maintain a semi-permeable barrier between the blood and tissue by forming inter-EC tight junctions (TJs), regulating selective transport of fluid and solutes. Overwhelming inflammation, as occurs in sepsis, disrupts these TJs, leading to leakage of fluid, proteins, and small molecules into the tissues. Mechanistically, disruption of capillary barrier function is mediated by small Rho-GTPases, such as RhoA, -B, and -C, which are activated by guanine nucleotide exchange factors (GEFs) and disrupted by GTPase-activating factors (GAPs). We previously reported that a mutation in a specific RhoB GAP (p190BRhoGAP) underlays a hereditary capillary leak syndrome. Tumor necrosis factor (TNF) treatment disrupts TJs in cultured human microvascular ECs, a model of capillary leak. This response requires new gene transcription and involves increased RhoB activation. However, the specific GEF that activates RhoB in capillary ECs remains unknown. Transcriptional profiling of cultured tight junction-forming human dermal microvascular endothelial cells (HDMECs) revealed that 17 GEFs were significantly induced by TNF. The function of each candidate GEF was assessed by short interfering RNA depletion and trans-endothelial electrical resistance screening. Knockown of ArhGEF10 reduced the TNF-induced loss of barrier which was phenocopied by RhoB or dual ArhGEF10/RhoB knockdown. ArhGEF10 knockdown also reduced the extent of TNF-induced RhoB activation and disruption at tight junctions. In a cell-free assay, immunoisolated ArhGEF10 selectively catalyzed nucleotide exchange to activate RhoB, but not RhoA or RhoC. We conclude ArhGEF10 is a TNF-induced RhoB-selective GEF that mediates TJ disruption and barrier loss in human capillary endothelial cells.
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Affiliation(s)
- Alamzeb Khan
- Department of Pediatrics, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Weiming Ni
- Department of Pediatrics, Yale School of Medicine, Yale University, New Haven, CT, USA
| | | | - Martin S Kluger
- Department of Immunobiology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Jordan S Pober
- Department of Immunobiology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Richard W Pierce
- Department of Pediatrics, Yale School of Medicine, Yale University, New Haven, CT, USA
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Vigh JP, Kincses A, Ozgür B, Walter FR, Santa-Maria AR, Valkai S, Vastag M, Neuhaus W, Brodin B, Dér A, Deli MA. Transendothelial Electrical Resistance Measurement across the Blood-Brain Barrier: A Critical Review of Methods. Micromachines (Basel) 2021; 12:mi12060685. [PMID: 34208338 PMCID: PMC8231150 DOI: 10.3390/mi12060685] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/04/2021] [Accepted: 06/08/2021] [Indexed: 01/25/2023]
Abstract
The blood–brain barrier (BBB) represents the tightest endothelial barrier within the cardiovascular system characterized by very low ionic permeability. Our aim was to describe the setups, electrodes, and instruments to measure electrical resistance across brain microvessels and culture models of the BBB, as well as critically assess the influence of often neglected physical and technical parameters such as temperature, viscosity, current density generated by different electrode types, surface size, circumference, and porosity of the culture insert membrane. We demonstrate that these physical and technical parameters greatly influence the measurement of transendothelial electrical resistance/resistivity (TEER) across BBB culture models resulting in severalfold differences in TEER values of the same biological model, especially in the low-TEER range. We show that elevated culture medium viscosity significantly increases, while higher membrane porosity decreases TEER values. TEER data measured by chopstick electrodes can be threefold higher than values measured by chamber electrodes due to different electrode size and geometry, resulting in current distribution inhomogeneity. An additional shunt resistance at the circumference of culture inserts results in lower TEER values. A detailed description of setups and technical parameters is crucial for the correct interpretation and comparison of TEER values of BBB models.
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Affiliation(s)
- Judit P. Vigh
- Institute of Biophysics, Biological Research Centre, 6726 Szeged, Hungary; (J.P.V.); (A.K.); (F.R.W.); (A.R.S.-M.); (S.V.)
- Doctoral School of Biology, University of Szeged, 6720 Szeged, Hungary
| | - András Kincses
- Institute of Biophysics, Biological Research Centre, 6726 Szeged, Hungary; (J.P.V.); (A.K.); (F.R.W.); (A.R.S.-M.); (S.V.)
| | - Burak Ozgür
- Department of Pharmacy, University of Copenhagen, 2100 Copenhagen, Denmark; (B.O.); (B.B.)
| | - Fruzsina R. Walter
- Institute of Biophysics, Biological Research Centre, 6726 Szeged, Hungary; (J.P.V.); (A.K.); (F.R.W.); (A.R.S.-M.); (S.V.)
| | - Ana Raquel Santa-Maria
- Institute of Biophysics, Biological Research Centre, 6726 Szeged, Hungary; (J.P.V.); (A.K.); (F.R.W.); (A.R.S.-M.); (S.V.)
| | - Sándor Valkai
- Institute of Biophysics, Biological Research Centre, 6726 Szeged, Hungary; (J.P.V.); (A.K.); (F.R.W.); (A.R.S.-M.); (S.V.)
| | - Mónika Vastag
- In Vitro Metabolism Research, Division of Pharmacology and Drug Safety, Gedeon Richter Plc., 1103 Budapest, Hungary;
| | - Winfried Neuhaus
- Center for Health and Bioresources, Competence Unit Molecular Diagnostics, AIT—Austrian Institute of Technology GmbH, 1210 Vienna, Austria;
| | - Birger Brodin
- Department of Pharmacy, University of Copenhagen, 2100 Copenhagen, Denmark; (B.O.); (B.B.)
| | - András Dér
- Institute of Biophysics, Biological Research Centre, 6726 Szeged, Hungary; (J.P.V.); (A.K.); (F.R.W.); (A.R.S.-M.); (S.V.)
- Correspondence: (A.D.); (M.A.D.)
| | - Mária A. Deli
- Institute of Biophysics, Biological Research Centre, 6726 Szeged, Hungary; (J.P.V.); (A.K.); (F.R.W.); (A.R.S.-M.); (S.V.)
- Correspondence: (A.D.); (M.A.D.)
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9
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Kriaučiūnaitė K, Pociūtė A, Kaušylė A, Pajarskienė J, Verkhratsky A, Pivoriūnas A. Concentration-dependent duality of bFGF in regulation of barrier properties of human brain endothelial cells. J Cell Physiol 2021; 236:7642-7654. [PMID: 33959949 DOI: 10.1002/jcp.30410] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 03/26/2021] [Indexed: 01/16/2023]
Abstract
Multiple paracrine factors regulate the barrier properties of human brain capillary endothelial cells (BCECs). Understanding the precise mode of action of these factors remains a challenging task, because of the limited availability of functionally competent BCECs and the use of serum-containing medium. In the present study, we employed a defined protocol for producing BCECs from human inducible pluripotent stem cells. We found that autocrine secretion of basic fibroblast growth factor (bFGF) is necessary for the establishment a tight BCECs barrier, as revealed by measurements of transendothelial electric resistance (TEER). In contrast, addition of exogenous bFGF in concentrations higher than 4 ng/ml inhibited TEER in a concentration-dependent manner. Exogenous bFGF did not significantly affect expression and distribution of tight junction proteins claudin-5, occludin and zonula occludens (ZO)-1. Treatment with FGF receptor blocker PD173074 (15 µM) suppressed inhibitory effects of bFGF and induced nuclear translocation of protein ZO-1. Inhibition of phosphoinositide 3-Kinase (PI-3K) with LY294002 (25 µM) significantly potentiated an inhibitory effect of bFGF on TEER indicating that PI-3K signalling pathway counteracts bFGF modulation of TEER. In conclusion, we show that autocrine bFGF secretion is necessary for the proper barrier function of BCECs, whereas exogenous bFGF in higher doses suppresses barrier resistance. Our findings demonstrate a dual role for bFGF in the regulation of BCEC barrier function.
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Affiliation(s)
- Karolina Kriaučiūnaitė
- Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania
| | - Agnė Pociūtė
- Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania
| | - Aida Kaušylė
- Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania
| | - Justina Pajarskienė
- Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania
| | - Alexei Verkhratsky
- Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania.,Faculty of Biology, Medicine, and Health, The University of Manchester, Manchester, UK.,Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Augustas Pivoriūnas
- Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania
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10
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Abstract
Herein, a 60-electrode array is fabricated down the length of a microchamber for analysis of a microphysiological system. The electrode array is fabricated by standard photolithographic, metallization, and etching techniques. Permutations of 2-wire impedance measurements (10 Hz to 1 MHz) are made along the length of the microchannel using a multiplexer, Gamry potentiostat, and custom Labview code. An impedance "heat map" is created via custom algorithms. Spatial resolution and mapping capabilities are exhibited using conductive NaCl solutions and 2D cell culture.
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Affiliation(s)
- Ashlyn T Young
- Joint Department of Biomedical Engineering, NC State University and UNC at Chapel Hill, Raleigh, NC, USA
| | - Vladimir A Pozdin
- Department of Electrical and Computer Engineering, Florida International University, Miami, FL, USA
| | - Michael Daniele
- Joint Department of Biomedical Engineering, NC State University and UNC at Chapel Hill, Raleigh, NC, USA.,Department of Electrical and Computer Engineering, NC State University, Raleigh, NC, USA
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Prashanth A, Donaghy H, Stoner SP, Hudson AL, Wheeler HR, Diakos CI, Howell VM, Grau GE, McKelvey KJ. Are In Vitro Human Blood-Brain-Tumor-Barriers Suitable Replacements for In Vivo Models of Brain Permeability for Novel Therapeutics? Cancers (Basel) 2021; 13:955. [PMID: 33668807 DOI: 10.3390/cancers13050955] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 02/21/2021] [Accepted: 02/23/2021] [Indexed: 12/19/2022] Open
Abstract
Simple Summary Brain cancers are a devastating disease with no cure. The aim of the study was to determine whether in vitro models can replace in vivo models to assess the brain permeability of novel drugs for brain cancer. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, our systematic review reveals that microfluidic-based in vitro models comprising stem cell-derived endothelial cells, and primary astrocytes, pericytes and neurons can, in part, replicate the physiological ability of in vivo models to mimic patient permeability data. This information will guide the development and use of in vitro models for novel therapeutics of unknown permeability for brain cancer. Abstract Background: High grade gliomas (HGG) are incapacitating and prematurely fatal diseases. To overcome the poor prognosis, novel therapies must overcome the selective and restricted permeability of the blood–brain barrier (BBB). This study critically evaluated whether in vitro human normal BBB and tumor BBB (BBTB) are suitable alternatives to “gold standard” in vivo models to determine brain permeability. Methods: A systematic review utilizing the PRISMA guidelines used English and full-text articles from the past 5 years in the PubMed, Embase, Medline and Scopus databases. Experimental studies employing human cell lines were included. Results: Of 1335 articles, the search identified 24 articles for evaluation after duplicates were removed. Eight in vitro and five in vivo models were identified with the advantages and disadvantages compared within and between models, and against patient clinical data where available. The greatest in vitro barrier integrity and stability, comparable to in vivo and clinical permeability data, were achieved in the presence of all cell types of the neurovascular unit: endothelial cells, astrocytes/glioma cells, pericytes and neurons. Conclusions: In vitro co-culture BBB models utilizing stem cell-derived or primary cells are a suitable proxy for brain permeability studies in order to reduce animal use in medical research.
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Bittner A, Gosselet F, Sevin E, Dehouck L, Ducray AD, Gaschen V, Stoffel MH, Cho H, Mevissen M. Time-Dependent Internalization of Polymer-Coated Silica Nanoparticles in Brain Endothelial Cells and Morphological and Functional Effects on the Blood-Brain Barrier. Int J Mol Sci 2021; 22:ijms22041657. [PMID: 33562136 PMCID: PMC7915594 DOI: 10.3390/ijms22041657] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 11/16/2022] Open
Abstract
Nanoparticle (NP)-assisted procedures including laser tissue soldering (LTS) offer advantages compared to conventional microsuturing, especially in the brain. In this study, effects of polymer-coated silica NPs used in LTS were investigated in human brain endothelial cells (ECs) and blood-brain barrier models. In the co-culture setting with ECs and pericytes, only the cell type directly exposed to NPs displayed a time-dependent internalization. No transfer of NPs between the two cell types was observed. Cell viability was decreased relatively to NP exposure duration and concentration. Protein expression of the nuclear factor ĸ-light-chain-enhancer of activated B cells and various endothelial adhesion molecules indicated no initiation of inflammation or activation of ECs after NP exposure. Differentiation of CD34+ ECs into brain-like ECs co-cultured with pericytes, blood-brain barrier (BBB) characteristics were obtained. The established endothelial layer reduced the passage of integrity tracer molecules. NP exposure did not result in alterations of junctional proteins, BBB formation or its integrity. In a 3-dimensional setup with an endothelial tube formation and tight junctions, barrier formation was not disrupted by the NPs and NPs do not seem to cross the blood-brain barrier. Our findings suggest that these polymer-coated silica NPs do not damage the BBB.
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Affiliation(s)
- Aniela Bittner
- Division of Veterinary Pharmacology and Toxicology, Vetsuisse Faculty, University of Bern, Länggassstrasse 124, 3012 Bern, Switzerland; (A.B.); (A.D.D.)
| | - Fabien Gosselet
- Blood-Brain-Barrier Laboratory, University of Artois, UR265, Faculté Jean Perrin, Rue Jean Souvraz–SP 18, 62307 Lens, France; (F.G.); (E.S.); (L.D.)
| | - Emmanuel Sevin
- Blood-Brain-Barrier Laboratory, University of Artois, UR265, Faculté Jean Perrin, Rue Jean Souvraz–SP 18, 62307 Lens, France; (F.G.); (E.S.); (L.D.)
| | - Lucie Dehouck
- Blood-Brain-Barrier Laboratory, University of Artois, UR265, Faculté Jean Perrin, Rue Jean Souvraz–SP 18, 62307 Lens, France; (F.G.); (E.S.); (L.D.)
| | - Angélique D. Ducray
- Division of Veterinary Pharmacology and Toxicology, Vetsuisse Faculty, University of Bern, Länggassstrasse 124, 3012 Bern, Switzerland; (A.B.); (A.D.D.)
| | - Véronique Gaschen
- Division of Veterinary Anatomy, Vetsuisse Faculty, University of Bern, Länggassstrasse 120, 3012 Bern, Switzerland; (V.G.); (M.H.S.)
| | - Michael H. Stoffel
- Division of Veterinary Anatomy, Vetsuisse Faculty, University of Bern, Länggassstrasse 120, 3012 Bern, Switzerland; (V.G.); (M.H.S.)
| | - Hansang Cho
- Institute of Quantum Biophysics, Department of Biophysics, Department of Intelligent Precision Healthcare Concergence, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, #868715 N-Center Suwon-si, Gyeonggi-do 16419, Korea;
| | - Meike Mevissen
- Division of Veterinary Pharmacology and Toxicology, Vetsuisse Faculty, University of Bern, Länggassstrasse 124, 3012 Bern, Switzerland; (A.B.); (A.D.D.)
- Correspondence: ; Tel.: +41-31-631-22-31
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Tu KH, Yu LS, Sie ZH, Hsu HY, Al-Jamal KT, Wang JTW, Chiang YY. Development of Real-Time Transendothelial Electrical Resistance Monitoring for an In Vitro Blood-Brain Barrier System. Micromachines (Basel) 2020; 12:mi12010037. [PMID: 33396953 PMCID: PMC7824195 DOI: 10.3390/mi12010037] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 12/21/2020] [Accepted: 12/25/2020] [Indexed: 11/16/2022]
Abstract
Three-dimensional (3D) cell cultures and organs-on-a-chip have been developed to construct microenvironments that resemble the environment within the human body and to provide a platform that enables clear observation and accurate assessments of cell behavior. However, direct observation of transendothelial electrical resistance (TEER) has been challenging. To improve the efficiency in monitoring the cell development in organs-on-a-chip, in this study, we designed and integrated commercially available TEER measurement electrodes into an in vitro blood-brain barrier (BBB)-on-chip system to quantify TEER variation. Moreover, a flowing culture medium was added to the monolayered cells to simulate the promotion of continuous shear stress on cerebrovascular cells. Compared with static 3D cell culture, the proposed BBB-on-chip integrated with electrodes could measure TEER in a real-time manner over a long period. It also allowed cell growth angle measurement, providing instant reports of cell growth information online. Overall, the results demonstrated that the developed system can aid in the quantification of the continuous cell-pattern variations for future studies in drug testing.
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Affiliation(s)
- Kai-Hong Tu
- Department of Mechanical Engineering, National Chung Hsing University, Taichung 402701, Taiwan; (K.-H.T.); (Z.-H.S.); (H.-Y.H.)
| | - Ling-Shan Yu
- Rapid Screening Research Center for Toxicology and Biomedicine, National Sun Yat-sen University, Kaohsiung 813016, Taiwan;
| | - Zong-Han Sie
- Department of Mechanical Engineering, National Chung Hsing University, Taichung 402701, Taiwan; (K.-H.T.); (Z.-H.S.); (H.-Y.H.)
| | - Han-Yi Hsu
- Department of Mechanical Engineering, National Chung Hsing University, Taichung 402701, Taiwan; (K.-H.T.); (Z.-H.S.); (H.-Y.H.)
| | - Khuloud T. Al-Jamal
- School of Cancer and Pharmaceutical Sciences, Faculty of Life Sciences & Medicine, King’s College London, London SE5 9NU, UK; (K.T.A.-J.); (J.T.-W.W.)
| | - Julie Tzu-Wen Wang
- School of Cancer and Pharmaceutical Sciences, Faculty of Life Sciences & Medicine, King’s College London, London SE5 9NU, UK; (K.T.A.-J.); (J.T.-W.W.)
| | - Ya-Yu Chiang
- Department of Mechanical Engineering, National Chung Hsing University, Taichung 402701, Taiwan; (K.-H.T.); (Z.-H.S.); (H.-Y.H.)
- i-Center for Advanced Science and Technology, National Chung Hsing University, Taichung 402701, Taiwan
- Correspondence: ; Tel.: +886-2284-0433
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Omarch G, Kippie Y, Mentor S, Ebrahim N, Fisher D, Murilla G, Swai H, Dube A. Comparative in vitro transportation of pentamidine across the blood-brain barrier using polycaprolactone nanoparticles and phosphatidylcholine liposomes. Artif Cells Nanomed Biotechnol 2019; 47:1428-1436. [PMID: 31007068 DOI: 10.1080/21691401.2019.1596923] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Nanoparticles (NPs) have gained importance in addressing drug delivery challenges across biological barriers. Here, we reformulated pentamidine, a drug used to treat Human African Trypanosomiasis (HAT) in polymer based nanoparticles and liposomes and compared their capability to enhance pentamidine penetration across blood brain barrier (BBB). Size, polydispersity index, zeta potential, morphology, pentamidine loading and drug release profiles were determined by various methods. Cytotoxicity was tested against the immortalized mouse brain endothelioma cells over 96 h. Moreover, cells monolayer integrity and transportation ability were examined for 24 h. Pentamidine-loaded polycaprolactone (PCL) nanoparticles had a mean size of 267.58, PDI of 0.25 and zeta potential of -28.1 mV and pentamidine-loaded liposomes had a mean size of 119.61 nm, PDI of 0.25 and zeta potential 11.78. Pentamidine loading was 0.16 µg/mg (w/w) and 0.17 µg/mg (w/w) in PCL NPs and liposomes respectively. PCL nanoparticles and liposomes released 12.13% and 22.21% of pentamidine respectively after 24 h. Liposomes transported 87% of the dose, PCL NPs 66% of the dose and free pentamidine penetration was 63% of the dose. These results suggest that liposomes are comparatively promising nanocarriers for transportation of pentamidine across BBB.
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Affiliation(s)
- Geofrey Omarch
- a School of Life Sciences , The Nelson Mandela African Institution of Science and Technology , Tengeru , Arusha , Tanzania.,b Tanzania Veterinary Laboratory Agency , Temeke , Dar es Salaam , Tanzania
| | - Yunus Kippie
- c School of Pharmacy , University of the Western Cape , Bellville , South Africa
| | - Shireen Mentor
- d School of Life Sciences , University of the Western Cape , Bellville , South Africa
| | - Naushaad Ebrahim
- c School of Pharmacy , University of the Western Cape , Bellville , South Africa
| | - David Fisher
- d School of Life Sciences , University of the Western Cape , Bellville , South Africa
| | - Grace Murilla
- e Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization , Kikuyu, Nairobi , Kenya
| | - Hulda Swai
- a School of Life Sciences , The Nelson Mandela African Institution of Science and Technology , Tengeru , Arusha , Tanzania
| | - Admire Dube
- c School of Pharmacy , University of the Western Cape , Bellville , South Africa
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Lian D, Yuan H, Yin X, Wu Y, He R, Huang Y, Chen Y. Puerarin inhibits hyperglycemia-induced inter-endothelial junction through suppressing endothelial Nlrp3 inflammasome activation via ROS-dependent oxidative pathway. Phytomedicine 2019; 55:310-319. [PMID: 30385134 DOI: 10.1016/j.phymed.2018.10.013] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Revised: 10/04/2018] [Accepted: 10/09/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND Recent studies indicate that vascular complications are closely related to diabetes mellitus; in particular, inflammatory-mediated endothelial dysfunction plays a crucial role in diabetes-induced cardiovascular diseases. Therefore, exploring effective methods to suppress endothelial dysfunction via inhibition of inflammatory responses is imperative. Puerarin (Pu), a flavonoid common in Pueraria, has been widely and successfully used to treat cardiovascular diseases in China for many years. However, information on its protective properties in hyperglycemia-induced vascular complications is insufficient. Hypothesis/Purpose: In this study, we investigate the protective effects of puerarin against high glucose-induced endothelial dysfunction and the underlying mechanism of the flavonoid. METHODS we investigated the protective effects of Pu against hyperglycemia-induced inter-endothelial junction by permeability and transendothelial electrical resistance (TEER) assay. In addition, changes in the Nlrp3 inflammasome activation via reactive oxygen species (ROS)-dependent oxidative pathway were investigated using western blot, immunofluorescence microscopy analyses and flow cytometry. ROS scavenger and Nlrp3 gene silencing were used to determine the roles of the ROS-Nlrp3 pathway involved in the molecular mechanism of Pu. RESULTS Our findings demonstrate that puerarin inhibits high glucose-induced Nlrp3 inflammasome formation and activation, as shown by fluorescence confocal microscopy and Western blot. Puerarin decreases Nlrp3 protein, which is a critical factor necessary to form an inflammasome complex. We demonstrate that puerarin exerts anti-oxidation and ROS scavenged effects, similar to apocynin (APO). Interestingly, thioredoxin-interacting protein (TXNIP) protein and TXNIP binding to Nlrp3 markedly decreased with puerarin treatment. Together with these changes, puerarin could decrease high mobility group box 1 (HMGB1) release from mouse vascular endothelial cell (mMVECs). We also demonstrate the decreased expression of the tight junction proteins ZO-1/ZO-2, which are related to endothelial permeability after stimulation by high glucose in endothelial cells. Puerarin could recover the gap junction protein and decrease monolayer cell permeability in endothelial cells. In conclusion, we reveal a new protection mechanism of puerarin that inhibits Nlrp3 inflammasome activation and decreases subsequent caspase-1 activation, triggering the release of HMGB1 by reducing ROS generation. CONCLUSIONS Our findings indicate that puerarin exhibits immense potential and specific therapeutic value in hyperglycemia-related cardiovascular disease and the development of innovative drugs.
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Affiliation(s)
- Dawei Lian
- School of Pharmaceutical, Guangzhou University of Chinese Medicine, Guangzhou University Town, No. 232 Waihuan Dong Rd., Panyu District, Guangzhou Higher Education Mega Center, Guangzhou 510000, China
| | - Huiqi Yuan
- School of Pharmaceutical, Guangzhou University of Chinese Medicine, Guangzhou University Town, No. 232 Waihuan Dong Rd., Panyu District, Guangzhou Higher Education Mega Center, Guangzhou 510000, China
| | - Xiongzhang Yin
- Department of Pharmacy, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095 Jiefang Avenue, Wuhan 430030, China
| | - Yanjiao Wu
- School of Pharmaceutical, Guangzhou University of Chinese Medicine, Guangzhou University Town, No. 232 Waihuan Dong Rd., Panyu District, Guangzhou Higher Education Mega Center, Guangzhou 510000, China
| | - Rongrong He
- Guangdong Engineering Research Center of Chinese Medicine & Disease Susceptibility, Jinan University, No. 601W. Huangpu Avenue, Guangzhou 510630, China
| | - Yi Huang
- Department of Stomatology, The First Affiliated Hospital, The school of Dental Medicine, Jinan University, No. 613W. Huangpu Avenue, Guangzhou 510630, China
| | - Yang Chen
- School of Pharmaceutical, Guangzhou University of Chinese Medicine, Guangzhou University Town, No. 232 Waihuan Dong Rd., Panyu District, Guangzhou Higher Education Mega Center, Guangzhou 510000, China.
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Hülper P, Veszelka S, Walter FR, Wolburg H, Fallier-Becker P, Piontek J, Blasig IE, Lakomek M, Kugler W, Deli MA. Acute effects of short-chain alkylglycerols on blood-brain barrier properties of cultured brain endothelial cells. Br J Pharmacol 2014; 169:1561-73. [PMID: 23617601 DOI: 10.1111/bph.12218] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 01/07/2013] [Accepted: 04/05/2013] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE The blood-brain barrier (BBB) restricts drug penetration to the brain preventing effective treatment of patients suffering from brain tumours. Intra-arterial injection of short-chain alkylglycerols (AGs) opens the BBB and increases delivery of molecules to rodent brain parenchyma in vivo. The mechanism underlying AG-mediated modification of BBB permeability is still unknown. Here, we have tested the effects of AGs on barrier properties of cultured brain microvascular endothelial cells. EXPERIMENTAL APPROACH The effects of two AGs, 1-O-pentylglycerol and 2-O-hexyldiglycerol were examined using an in vitro BBB model consisting of primary cultures of rat brain endothelial cells, co-cultured with rat cerebral glial cells. Integrity of the paracellular, tight junction-based, permeation route was analysed by functional assays, immunostaining for junctional proteins, freeze-fracture electron microscopy, and analysis of claudin-claudin trans-interactions. KEY RESULTS AG treatment (5 min) reversibly reduced transendothelial electrical resistance and increased BBB permeability for fluorescein accompanied by changes in cell morphology and immunostaining for claudin-5 and β-catenin. These short-term changes were not accompanied by alterations of inter-endothelial tight junction strand complexity or the trans-interaction of claudin-5. CONCLUSION AND IMPLICATIONS AG-mediated increase in brain endothelial paracellular permeability was short, reversible and did not affect tight junction strand complexity. Redistribution of junctional proteins and alterations in the cell shape indicate the involvement of the cytoskeleton in the action of AGs. These data confirm the results from in vivo studies in rodents characterizing AGs as adjuvants that transiently open the BBB.
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Affiliation(s)
- P Hülper
- Department of Pediatrics I, University Medical Center Göttingen, Göttingen, Germany.
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Abstract
Cell culture models of the blood-brain barrier (BBB) are useful tools to study the functionality of the BBB in health and disease. Several good in vitro BBB models are available from different species. However, most brain endothelial cells lose some of their in vivo BBB phenotype in culture. Porcine brain endothelial cells (PBECs) tend to retain most of their in vivo BBB characteristics and usually give higher transendothelial electrical resistance (TEER, representing functional well-developed tight junctions) compared to brain endothelial cells from other species. The protocol described in this unit gives detailed instructions for isolation and culture of PBECs from fresh porcine brains. This porcine BBB model generates high TEER without the need for co-culture with astrocytes. However, astrocyte-derived factors can be introduced to the system through the use of astrocyte-conditioned medium or co-culture with astrocytes, which may be necessary for further enhancing the BBB phenotype for certain complex studies.
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Affiliation(s)
- Adjanie Patabendige
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
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Heffern CT, Pocivavsek L, Birukova AA, Moldobaeva N, Bochkov VN, Lee KY, Birukov KG. Thermodynamic and kinetic investigations of the release of oxidized phospholipids from lipid membranes and its effect on vascular integrity. Chem Phys Lipids 2013; 175-176:9-19. [PMID: 23911706 DOI: 10.1016/j.chemphyslip.2013.07.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 05/30/2013] [Accepted: 07/17/2013] [Indexed: 11/20/2022]
Abstract
The lipid membrane not only provides a rich interface with an array of receptor signaling complexes with which a cell communicates, but it also serves as a source of lipid derived bioactive molecules. In pathologic conditions of acute lung injury (ALI) associated with activation of oxidative stress, unsaturated phosphatidyl cholines overlooking a luminal space undergo oxidation leading to generation of fragmented phospholipids such as 1-palmitoyl-2-hydroxy-sn-glycero-3-phosphocholine (lysoPC), or 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (PAPC) full length oxygenation products (oxPAPC). Using Langmuir monolayers as models of the lipid bilayer, we evaluated the propensity of these phospholipids to solubilize from the cell membrane. The results suggest that lysoPC is rapidly released as it is produced, while oxPAPC has a longer membrane bound lifetime. After being released from cell membranes, these oxidized phospholipids exhibit potent agonist-like effects on neighboring cells. Therefore, we correlate the presence of the two phospholipid groups with the onset and resolution of increased vascular leakiness associated with ALI through testing their effect on vascular endothelial barrier integrity. Our work shows that cells respond differently to these two groups of products of phosphatidyl choline oxidation. LysoPC disrupts cell-cell junctions and increases endothelial permeability while oxPAPC enhances endothelial barrier. These data suggest a model whereby rapid release of lysoPC results in onset of ALI associated vascular leak, and the release of a reserve of oxPAPC as oxidative stress subsides restores the vascular barrier properties.
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Singh JS, Haroldson TA, Patel SP. Characteristics of the low density corneal endothelial monolayer. Exp Eye Res 2013; 115:239-45. [PMID: 23830909 DOI: 10.1016/j.exer.2013.06.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 06/13/2013] [Accepted: 06/24/2013] [Indexed: 11/21/2022]
Abstract
Corneal endothelial cells form a leaky barrier on the posterior surface of the cornea, allowing influx of nutrient-carrying aqueous humor through the paracellular space and efflux of excess fluid. Corneal edema arises when the density of these non-proliferative endothelial cells declines from endothelial disease or intraocular surgery. The cellular changes occurring at low densities are ill-defined. We therefore investigated the paracellular pathway of corneal endothelial cell monolayers of varying density to determine alterations occurring in paracellular permeability and monolayer morphology. Primary cultures of bovine corneal endothelial cells (BCECs) were passaged onto permeable supports under varying culture conditions to obtain confluent monolayers of <1000, 1000-1999 and >2000 cells/mm(2). Culture growth was monitored by transendothelial electrical resistance measurements. Diffusional permeability to sodium fluorescein, FITC-dextran MW 4000 or FITC-dextran MW 20,000 was measured. Confluent cultures were also analyzed by immunofluorescence localization of the tight junction protein ZO-1 and by transmission electron microscopy. For comparison, we evaluated ZO-1 for low and high density human corneal endothelium. Our results showed that all BCEC cultures grew to the same final transendothelial electrical resistance regardless of final density. In the diffusional permeability assay, permeability increased significantly only for the smallest tracer molecule (sodium fluorescein) in the lowest density monolayers (<1000 cells/mm(2)). ZO-1 immunofluorescence distinctly localized to intercellular junctions in high density BCEC cultures but had more diffuse localization at lower densities. Transmission electron microscopy imaging revealed cells with thinner cross-sectional profiles and longer overlapping intercellular processes at low density relative to high density cultures. Low density human corneal endothelium lacked the diffuse ZO-1 distribution seen in BCECs. Our data supports the hypothesis that barrier integrity is the primary function disrupted in low density corneal endothelial monolayers and contradicts the idea of a linear decline in barrier function with decreasing cell density.
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