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Tremblay TL, Alata W, Slinn J, Baumann E, Delaney CE, Moreno M, Haqqani AS, Stanimirovic DB, Hill JJ. The proteome of the blood-brain barrier in rat and mouse: highly specific identification of proteins on the luminal surface of brain microvessels by in vivo glycocapture. Fluids Barriers CNS 2024; 21:23. [PMID: 38433215 PMCID: PMC10910681 DOI: 10.1186/s12987-024-00523-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 02/19/2024] [Indexed: 03/05/2024] Open
Abstract
BACKGROUND The active transport of molecules into the brain from blood is regulated by receptors, transporters, and other cell surface proteins that are present on the luminal surface of endothelial cells at the blood-brain barrier (BBB). However, proteomic profiling of proteins present on the luminal endothelial cell surface of the BBB has proven challenging due to difficulty in labelling these proteins in a way that allows efficient purification of these relatively low abundance cell surface proteins. METHODS Here we describe a novel perfusion-based labelling workflow: in vivo glycocapture. This workflow relies on the oxidation of glycans present on the luminal vessel surface via perfusion of a mild oxidizing agent, followed by subsequent isolation of glycoproteins by covalent linkage of their oxidized glycans to hydrazide beads. Mass spectrometry-based identification of the isolated proteins enables high-confidence identification of endothelial cell surface proteins in rats and mice. RESULTS Using the developed workflow, 347 proteins were identified from the BBB in rat and 224 proteins in mouse, for a total of 395 proteins in both species combined. These proteins included many proteins with transporter activity (73 proteins), cell adhesion proteins (47 proteins), and transmembrane signal receptors (31 proteins). To identify proteins that are enriched in vessels relative to the entire brain, we established a vessel-enrichment score and showed that proteins with a high vessel-enrichment score are involved in vascular development functions, binding to integrins, and cell adhesion. Using publicly-available single-cell RNAseq data, we show that the proteins identified by in vivo glycocapture were more likely to be detected by scRNAseq in endothelial cells than in any other cell type. Furthermore, nearly 50% of the genes encoding cell-surface proteins that were detected by scRNAseq in endothelial cells were also identified by in vivo glycocapture. CONCLUSIONS The proteins identified by in vivo glycocapture in this work represent the most complete and specific profiling of proteins on the luminal BBB surface to date. The identified proteins reflect possible targets for the development of antibodies to improve the crossing of therapeutic proteins into the brain and will contribute to our further understanding of BBB transport mechanisms.
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Affiliation(s)
- Tammy-Lynn Tremblay
- Human Health Therapeutics, National Research Council Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Wael Alata
- Human Health Therapeutics, National Research Council Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
- Biology Program, New York University Abu Dhabi, Saadiyat Island Campus, P.O. Box 129188, Abu Dhabi, United Arab Emirates
| | - Jacqueline Slinn
- Human Health Therapeutics, National Research Council Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Ewa Baumann
- Human Health Therapeutics, National Research Council Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Christie E Delaney
- Human Health Therapeutics, National Research Council Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Maria Moreno
- Human Health Therapeutics, National Research Council Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Arsalan S Haqqani
- Human Health Therapeutics, National Research Council Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Danica B Stanimirovic
- Human Health Therapeutics, National Research Council Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Jennifer J Hill
- Human Health Therapeutics, National Research Council Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada.
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Gauthier C, El Cheikh K, Basile I, Daurat M, Morère E, Garcia M, Maynadier M, Morère A, Gary-Bobo M. Cation-independent mannose 6-phosphate receptor: From roles and functions to targeted therapies. J Control Release 2024; 365:759-772. [PMID: 38086445 DOI: 10.1016/j.jconrel.2023.12.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 12/07/2023] [Accepted: 12/08/2023] [Indexed: 12/17/2023]
Abstract
The cation-independent mannose 6-phosphate receptor (CI-M6PR) is a ubiquitous transmembrane receptor whose main intracellular role is to direct enzymes carrying mannose 6-phosphate moieties to lysosomal compartments. Recently, the small membrane-bound portion of this receptor has appeared to be implicated in numerous pathophysiological processes. This review presents an overview of the main ligand partners and the roles of CI-M6PR in lysosomal storage diseases, neurology, immunology and cancer fields. Moreover, this membrane receptor has already been noted for its strong potential in therapeutic applications thanks to its cellular internalization activity and its ability to address pathogenic factors to lysosomes for degradation. A number of therapeutic delivery approaches using CI-M6PR, in particular with enzymes, antibodies or nanoparticles, are currently being proposed.
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Affiliation(s)
- Corentin Gauthier
- NanoMedSyn, Montpellier, France; IBMM, Univ Montpellier, CNRS, ENSCM, Montpellier, France
| | | | | | | | - Elodie Morère
- NanoMedSyn, Montpellier, France; IBMM, Univ Montpellier, CNRS, ENSCM, Montpellier, France
| | | | | | - Alain Morère
- IBMM, Univ Montpellier, CNRS, ENSCM, Montpellier, France
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Moos T, Thomsen MS, Burkhart A, Hede E, Laczek B. Targeted transport of biotherapeutics at the blood-brain barrier. Expert Opin Drug Deliv 2023; 20:1823-1838. [PMID: 38059358 DOI: 10.1080/17425247.2023.2292697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 12/05/2023] [Indexed: 12/08/2023]
Abstract
INTRODUCTION The treatment of neurological diseases is significantly hampered by the lack of available therapeutics. A major restraint for the development of drugs is denoted by the presence of the blood-brain barrier (BBB), which precludes the transfer of biotherapeutics to the brain due to size restraints. AREAS COVERED Novel optimism for transfer of biotherapeutics to the brain has been generated via development of targeted therapeutics to nutrient transporters expressed by brain capillary endothelial cells (BCECs). Targeting approaches with antibodies acting as biological drug carriers allow for proteins and genetic material to enter the brain, and qualified therapy using targeted proteins for protein replacement has been observed in preclinical models and now emerging in the clinic. Viral vectors denote an alternative for protein delivery to the brain by uptake and transduction of BCECs, or by transport through the BBB leading to neuronal transduction. EXPERT OPINION The breaching of the BBB to large molecules has opened for treatment of diseases in the brain. A sturdier understanding of how biotherapeutics undergo transport through the BBB and how successful transport into the brain can be monitored is required to further improve the translation from successful preclinical studies to the clinic.
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Affiliation(s)
- Torben Moos
- Neurobiology Research and Drug Delivery, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Maj Schneider Thomsen
- Neurobiology Research and Drug Delivery, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Annette Burkhart
- Neurobiology Research and Drug Delivery, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Eva Hede
- Neurobiology Research and Drug Delivery, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Bartosz Laczek
- Neurobiology Research and Drug Delivery, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
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4
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Mucopolysaccharidoses and the blood-brain barrier. Fluids Barriers CNS 2022; 19:76. [PMID: 36117162 PMCID: PMC9484072 DOI: 10.1186/s12987-022-00373-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 09/06/2022] [Indexed: 11/10/2022] Open
Abstract
Mucopolysaccharidoses comprise a set of genetic diseases marked by an enzymatic dysfunction in the degradation of glycosaminoglycans in lysosomes. There are eight clinically distinct types of mucopolysaccharidosis, some with various subtypes, based on which lysosomal enzyme is deficient and symptom severity. Patients with mucopolysaccharidosis can present with a variety of symptoms, including cognitive dysfunction, hepatosplenomegaly, skeletal abnormalities, and cardiopulmonary issues. Additionally, the onset and severity of symptoms can vary depending on the specific disorder, with symptoms typically arising during early childhood. While there is currently no cure for mucopolysaccharidosis, there are clinically approved therapies for the management of clinical symptoms, such as enzyme replacement therapy. Enzyme replacement therapy is typically administered intravenously, which allows for the systemic delivery of the deficient enzymes to peripheral organ sites. However, crossing the blood-brain barrier (BBB) to ameliorate the neurological symptoms of mucopolysaccharidosis continues to remain a challenge for these large macromolecules. In this review, we discuss the transport mechanisms for the delivery of lysosomal enzymes across the BBB. Additionally, we discuss the several therapeutic approaches, both preclinical and clinical, for the treatment of mucopolysaccharidoses.
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5
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Transcytosis of tanycytes in the circumventricular organs of adult mouse brain. Neurosci Lett 2022; 779:136633. [DOI: 10.1016/j.neulet.2022.136633] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 03/26/2022] [Accepted: 04/11/2022] [Indexed: 12/18/2022]
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Toth AE, Holst MR, Nielsen MS. Vesicular Transport Machinery in Brain Endothelial Cells: What We Know and What We Do not. Curr Pharm Des 2020; 26:1405-1416. [PMID: 32048959 DOI: 10.2174/1381612826666200212113421] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 12/03/2019] [Indexed: 12/20/2022]
Abstract
The vesicular transport machinery regulates numerous essential functions in cells such as cell polarity, signaling pathways, and the transport of receptors and their cargoes. From a pharmaceutical perspective, vesicular transport offers avenues to facilitate the uptake of therapeutic agents into cells and across cellular barriers. In order to improve receptor-mediated transcytosis of biologics across the blood-brain barrier and into the diseased brain, a detailed understanding of intracellular transport mechanisms is essential. The vesicular transport machinery is a highly complex network and involves an array of protein complexes, cytosolic adaptor proteins, and the subcellular structures of the endo-lysosomal system. The endo-lysosomal system includes several types of vesicular entities such as early, late, and recycling endosomes, exosomes, ectosomes, retromer-coated vesicles, lysosomes, trans-endothelial channels, and tubules. While extensive research has been done on the trafficking system in many cell types, little is known about vesicular trafficking in brain endothelial cells. Consequently, assumptions on the transport system in endothelial cells are based on findings in polarised epithelial cells, although recent studies have highlighted differences in the endothelial system. This review highlights aspects of the vesicular trafficking machinery in brain endothelial cells, including recent findings, limitations, and opportunities for further studies.
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Affiliation(s)
- Andrea E Toth
- Department of Biomedicine, Faculty of Health, Aarhus University, Høegh-Guldberg Gade 10, 8000 Aarhus C, Denmark
| | - Mikkel R Holst
- Department of Biomedicine, Faculty of Health, Aarhus University, Høegh-Guldberg Gade 10, 8000 Aarhus C, Denmark
| | - Morten S Nielsen
- Department of Biomedicine, Faculty of Health, Aarhus University, Høegh-Guldberg Gade 10, 8000 Aarhus C, Denmark
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Hede E, Christiansen CB, Heegaard CW, Moos T, Burkhart A. Gene therapy to the blood-brain barrier with resulting protein secretion as a strategy for treatment of Niemann Picks type C2 disease. J Neurochem 2020; 156:290-308. [PMID: 32072649 DOI: 10.1111/jnc.14982] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 01/15/2020] [Accepted: 02/10/2020] [Indexed: 12/11/2022]
Abstract
Treatment of many diseases affecting the central nervous system (CNS) is complicated by the inability of several therapeutics to cross the blood-brain barrier (BBB). Genetically modifying brain capillary endothelial cells (BCECs) denotes an approach to overcome the limitations of the BBB by turning BCECs into recombinant protein factories. This will result in protein secretion toward both the brain and peripheral circulation, which is particularly relevant in genetic diseases, like lysosomal storage diseases (LSD), where cells are ubiquitously affected both in the CNS and the periphery. Here we investigated transfection of primary rat brain capillary endothelial cells (rBCECs) for synthesis and secretion of recombinant NPC2, the protein deficient in the lysosomal cholesterol storage disease Niemann Pick type C2. We demonstrate prominent NPC2 gene induction and protein secretion in 21% of BCECs in non-mitotic monocultures with a biological effect on NPC2-deficient fibroblasts as verified from changes in filipin III staining of cholesterol deposits. By comparison the transfection efficiency was 75% in HeLa-cells, known to persist in a mitotic state. When co-cultured with primary rat astrocytes in conditions with maintained BBB properties 7% BCECs were transfected, clearly suggesting that induction of BBB properties with polarized conditions of the non-mitotic BCECs influences the transfection efficacy and secretion directionality. In conclusion, non-viral gene therapy to rBCECs leads to protein secretion and signifies a method for NPC2 to target cells inside the CNS otherwise inaccessible because of the presence of the BBB. However, obtaining high transfection efficiencies is crucial in order to achieve sufficient therapeutic effects. Cover Image for this issue: https://doi.org/10.1111/jnc.15050.
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Affiliation(s)
- Eva Hede
- Laboratory of Neurobiology, Biomedicine Group, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Christine B Christiansen
- Laboratory of Neurobiology, Biomedicine Group, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Christian W Heegaard
- Department of Molecular Biology and Genetics - Molecular Nutrition, Aarhus University, Aarhus, Denmark
| | - Torben Moos
- Laboratory of Neurobiology, Biomedicine Group, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Annette Burkhart
- Laboratory of Neurobiology, Biomedicine Group, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
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8
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Helms HCC, Kristensen M, Saaby L, Fricker G, Brodin B. Drug Delivery Strategies to Overcome the Blood-Brain Barrier (BBB). Handb Exp Pharmacol 2020; 273:151-183. [PMID: 33367937 DOI: 10.1007/164_2020_403] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The brain capillary endothelium serves both as an exchange site for gases and solutes between blood and brain and as a protective fence against neurotoxic compounds from the blood. While this "blood-brain barrier" (BBB) function protects the fragile environment in the brain, it also poses a tremendous challenge for the delivery of drug compounds to the brain parenchyma. Paracellular brain uptake of drug compounds is limited by the physical tightness of the endothelium, which is tightly sealed with junction complexes. Transcellular uptake of lipophilic drug compounds is limited by the activity of active efflux pumps in the luminal membrane. As a result, the majority of registered CNS drug compounds are small lipophilic compounds which are not efflux transporter substrates. Small molecule CNS drug development therefore focuses on identifying compounds with CNS target affinity and modifies these in order to optimize lipophilicity and decrease efflux pump interactions. Since efflux pump activity is limiting drug uptake, it has been investigated whether coadministration of drug compounds with efflux pump inhibitors could increase drug uptake. While the concept works to some extent, a lot of challenges have been encountered in terms of obtaining efficient inhibition while avoiding adverse effects.Some CNS drug compounds enter the brain via nutrient transport proteins, an example is the levodopa, a prodrug of Dopamine, which crosses the BBB via the large neutral amino acid transporter LAT1. While carrier-mediated transport of drug compounds may seem attractive, the development of drugs targeting transporters is very challenging, since the compounds should have a good fit to the binding site, while still maintaining their CNS target affinity.Receptor-mediated transport of drug compounds, especially biotherapeutics, conjugated to a receptor-binding ligand has shown some promise, although the amounts transported are rather low. This also holds true for drug-conjugation to cell-penetrating peptides. Due to the low uptake of biotherapeutics, barrier-breaching approaches such as mannitol injections and focused ultrasound have been employed with some success to patient groups with no other treatment options.
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Affiliation(s)
| | - Mie Kristensen
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lasse Saaby
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Bioneer-Farma, Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Gert Fricker
- Institute of Pharmacy and Molecular Biotechnology, Ruprecht-Karls-University, Heidelberg, Germany
| | - Birger Brodin
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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9
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Johnsen KB, Burkhart A, Thomsen LB, Andresen TL, Moos T. Targeting the transferrin receptor for brain drug delivery. Prog Neurobiol 2019; 181:101665. [DOI: 10.1016/j.pneurobio.2019.101665] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 07/10/2019] [Accepted: 07/18/2019] [Indexed: 02/07/2023]
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10
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Toth AE, Nielsen SSE, Tomaka W, Abbott NJ, Nielsen MS. The endo-lysosomal system of bEnd.3 and hCMEC/D3 brain endothelial cells. Fluids Barriers CNS 2019; 16:14. [PMID: 31142333 PMCID: PMC6542060 DOI: 10.1186/s12987-019-0134-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 05/03/2019] [Indexed: 01/08/2023] Open
Abstract
Background Brain endothelial cell-based in vitro models are among the most versatile tools in blood–brain barrier research for testing drug penetration to the central nervous system. Transcytosis of large pharmaceuticals across the brain capillary endothelium involves the complex endo-lysosomal system. This system consists of several types of vesicle, such as early, late and recycling endosomes, retromer-positive structures, and lysosomes. Since the endo-lysosomal system in endothelial cell lines of in vitro blood–brain barrier models has not been investigated in detail, our aim was to characterize this system in different models. Methods For the investigation, we have chosen two widely-used models for in vitro drug transport studies: the bEnd.3 mouse and the hCMEC/D3 human brain endothelial cell line. We compared the structures and attributes of their endo-lysosomal system to that of primary porcine brain endothelial cells. Results We detected significant differences in the vesicular network regarding number, morphology, subcellular distribution and lysosomal activity. The retromer-positive vesicles of the primary cells were distinct in many ways from those of the cell lines. However, the cell lines showed higher lysosomal degradation activity than the primary cells. Additionally, the hCMEC/D3 possessed a strikingly unique ratio of recycling endosomes to late endosomes. Conclusions Taken together our data identify differences in the trafficking network of brain endothelial cells, essentially mapping the endo-lysosomal system of in vitro blood–brain barrier models. This knowledge is valuable for planning the optimal route across the blood–brain barrier and advancing drug delivery to the brain. Electronic supplementary material The online version of this article (10.1186/s12987-019-0134-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Andrea E Toth
- Department of Biomedicine, Faculty of Health, Aarhus University, Ole Worms Allé 3, 8000, Aarhus, Denmark. .,Lundbeck Foundation, Research Initiative on Brain Barriers and Drug Delivery, Scherfigsvej 7, 2100, Copenhagen, Denmark.
| | - Simone S E Nielsen
- Department of Biomedicine, Faculty of Health, Aarhus University, Ole Worms Allé 3, 8000, Aarhus, Denmark.,Lundbeck Foundation, Research Initiative on Brain Barriers and Drug Delivery, Scherfigsvej 7, 2100, Copenhagen, Denmark
| | - Weronika Tomaka
- Department of Biomedicine, Faculty of Health, Aarhus University, Ole Worms Allé 3, 8000, Aarhus, Denmark
| | - N Joan Abbott
- Institute of Pharmaceutical Science, King's College London, 150 Stamford Street, SE1 9NH, London, UK
| | - Morten S Nielsen
- Department of Biomedicine, Faculty of Health, Aarhus University, Ole Worms Allé 3, 8000, Aarhus, Denmark. .,Lundbeck Foundation, Research Initiative on Brain Barriers and Drug Delivery, Scherfigsvej 7, 2100, Copenhagen, Denmark.
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Villaseñor R, Lampe J, Schwaninger M, Collin L. Intracellular transport and regulation of transcytosis across the blood-brain barrier. Cell Mol Life Sci 2019; 76:1081-1092. [PMID: 30523362 PMCID: PMC6513804 DOI: 10.1007/s00018-018-2982-x] [Citation(s) in RCA: 127] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 11/06/2018] [Accepted: 11/26/2018] [Indexed: 12/31/2022]
Abstract
The blood-brain barrier is a dynamic multicellular interface that regulates the transport of molecules between the blood circulation and the brain parenchyma. Proteins and peptides required for brain homeostasis cross the blood-brain barrier via transcellular transport, but the mechanisms that control this pathway are not well characterized. Here, we highlight recent studies on intracellular transport and transcytosis across the blood-brain barrier. Endothelial cells at the blood-brain barrier possess an intricate endosomal network that allows sorting to diverse cellular destinations. Internalization from the plasma membrane, endosomal sorting, and exocytosis all contribute to the regulation of transcytosis. Transmembrane receptors and blood-borne proteins utilize different pathways and mechanisms for transport across brain endothelial cells. Alterations to intracellular transport in brain endothelial cells during diseases of the central nervous system contribute to blood-brain barrier disruption and disease progression. Harnessing the intracellular sorting mechanisms at the blood-brain barrier can help improve delivery of biotherapeutics to the brain.
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Affiliation(s)
- Roberto Villaseñor
- Roche Pharma Research and Early Development (pRED), Pharmaceutical Sciences, Roche Innovation Center, Basel, Switzerland.
| | - Josephine Lampe
- Institute for Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Lübeck, Germany
- DZHK (German Research Centre for Cardiovascular Research), Partner Site Hamburg/Lübeck/Kiel, Germany
| | - Markus Schwaninger
- Institute for Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Lübeck, Germany
- DZHK (German Research Centre for Cardiovascular Research), Partner Site Hamburg/Lübeck/Kiel, Germany
| | - Ludovic Collin
- Roche Pharma Research and Early Development (pRED), Neuro-Immunology, Roche Innovation Center, Basel, Switzerland.
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Hersom M, Goldeman C, Pretzer N, Brodin B. Validation of reference genes for normalization of real-time quantitative PCR studies of gene expression in brain capillary endothelial cells cultured in vitro. Mol Cell Neurosci 2018; 93:27-35. [PMID: 30315869 DOI: 10.1016/j.mcn.2018.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 10/04/2018] [Accepted: 10/08/2018] [Indexed: 10/28/2022] Open
Abstract
BACKGROUND The genes encoding β-actin and GAPDH are two of the most commonly used reference genes for normalization in in vitro blood-brain barrier studies. Studies have, however, shown that these reference genes might not always be the best choice. The aim of the present study was to evaluate 10 reference genes for use in mRNA profiling studies in primary cultures of brain endothelial cells of bovine origin. METHODS Gene evaluations were performed by qPCR in mono-culture and in co-cultures with astrocytes. The expression of reference genes was furthermore investigated during culture. Qbase+ software was used to analyze the stability of the tested genes and for determinations of the optimal number of reference genes. RESULTS The stability of the reference genes varied between the culture configurations, but for all culture configurations we found that the optimal number of reference genes were two. PMM-1, RPL13A and β-actin were the most stable genes in mono-cultures, non-contact co-culture and contact co-culture respectively. For studies comparing gene expression between different culture configurations the optimal number of reference genes was three and RPL13A was found to be most stable. During cell culture a number of four reference genes were found to be optimal and YWHAZ was found to be the most stable gene. β-actin and GAPDH were found to be the least stable genes during culture. CONCLUSION Overall we found that the validation of reference genes was important in order to normalize target gene expression correctly, and suggest sets of reference genes to be used under different experimental conditions, in order to quantify mRNA transcript levels in blood-brain barrier cell models correctly.
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Affiliation(s)
- Maria Hersom
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Charlotte Goldeman
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Natasia Pretzer
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Birger Brodin
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark.
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13
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In Vitro Models for Studying Transport Across Epithelial Tissue Barriers. Ann Biomed Eng 2018; 47:1-21. [DOI: 10.1007/s10439-018-02124-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 08/28/2018] [Indexed: 12/16/2022]
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14
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Galla HJ. Monocultures of primary porcine brain capillary endothelial cells: Still a functional in vitro model for the blood-brain-barrier. J Control Release 2018; 285:172-177. [PMID: 30005905 DOI: 10.1016/j.jconrel.2018.07.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 06/26/2018] [Accepted: 07/09/2018] [Indexed: 12/21/2022]
Abstract
The main obstacle for the treatment of brain diseases is the restriction of the passage of pharmaceuticals across the blood-brain barrier. Endothelial cells line up the cerebral micro vessels and prevent the uncontrolled transfer of polar substances by intercellular tight junctions. In addition to this physical barrier, active transporters of the multi-drug-resistance prevent the passage of hydrophobic substances by refluxing them back to the blood stream. This paper reviews the development and selected applications of an in vitro porcine brain derived primary cell culture system established in the authors lab that closely resembles the BBB in vivo and could thus be used to study beyond other applications drug delivery to the brain. An essential technique to control the intactness or destruction of the barrier, the impedance spectroscopy, will be introduced. It will be shown that nanoparticles can cross the blood brain barrier by two mechanisms: opening the tight junctions and thus allowing parallel import of substances into the brain as well as receptor mediated endocytosis using brain specific target molecules. However cytotoxic effects have to be considered as well which beside standard cytotoxicity assays could be also determined by impedance technology. Moreover it will be shown that enzymes e.g. for enzyme replacement therapy could be transferred across the barrier by proper tuning or chemical modification of the enzyme. Since this review is based on a conference presentation it will mainly focus on applications of the monoculture system developed in the authors lab which under given culture conditions is useful due to its easy availability, robustness, good reproducibility and also due to its simplicity. Improvements of this model made by other groups will be acknowledged but not discussed here in detail.
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Affiliation(s)
- Hans-Joachim Galla
- Institute for Biochemistry, Westfälische Wilhems Universität,Münster, Wilhelm Klemm Str. 2, 48149 Münster, Germany.
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15
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Toth AE, Siupka P, P Augustine TJ, Venø ST, Thomsen LB, Moos T, Lohi HT, Madsen P, Lykke-Hartmann K, Nielsen MS. The Endo-Lysosomal System of Brain Endothelial Cells Is Influenced by Astrocytes In Vitro. Mol Neurobiol 2018; 55:8522-8537. [PMID: 29560581 DOI: 10.1007/s12035-018-0988-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 03/05/2018] [Indexed: 12/28/2022]
Abstract
Receptor- and adsorptive-mediated transport through brain endothelial cells (BEC) of the blood-brain barrier (BBB) involves a complex array of subcellular vesicular structures, the endo-lysosomal system. It consists of several types of vesicles, such as early, recycling, and late endosomes, retromer-positive structures, and lysosomes. Since this system is important for receptor-mediated transcytosis of drugs across brain capillaries, our aim was to characterise the endo-lysosomal system in BEC with emphasis on their interactions with astrocytes. We used primary porcine BEC in monoculture and in co-culture with primary rat astrocytes. The presence of astrocytes changed the intraendothelial vesicular network and significantly impacted vesicular number, morphology, and distribution. Additionally, gene set enrichment analysis revealed that 60 genes associated with vesicular trafficking showed altered expression in co-cultured BEC. Cytosolic proteins involved in subcellular trafficking were investigated to mark transport routes, such as RAB25 for transcytosis. Strikingly, the adaptor protein called AP1-μ1B, important for basolateral sorting in epithelial cells, was not expressed in BEC. Altogether, our data pin-point unique features of BEC trafficking network, essentially mapping the endo-lysosomal system of in vitro BBB models. Consequently, our findings constitute a valuable basis for planning the optimal route across the BBB when advancing drug delivery to the brain.
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Affiliation(s)
- Andrea E Toth
- Department of Biomedicine, Faculty of Health, Aarhus University, Ole Worms Allé 3, 8000, Aarhus, Denmark.,Lundbeck Foundation, Research Initiative on Brain Barriers and Drug Delivery, Scherfigsvej 7, 2100, Copenhagen, Denmark
| | - Piotr Siupka
- Department of Biomedicine, Faculty of Health, Aarhus University, Ole Worms Allé 3, 8000, Aarhus, Denmark.,Lundbeck Foundation, Research Initiative on Brain Barriers and Drug Delivery, Scherfigsvej 7, 2100, Copenhagen, Denmark
| | - Thomas J P Augustine
- Research Program for Molecular Neurology, Helsinki University, Haartmaninkatu 8, 00290, Helsinki, Finland
| | - Susanne T Venø
- Department of Biomedicine, Faculty of Health, Aarhus University, Ole Worms Allé 3, 8000, Aarhus, Denmark.,Lundbeck Foundation, Research Initiative on Brain Barriers and Drug Delivery, Scherfigsvej 7, 2100, Copenhagen, Denmark
| | - Louiza B Thomsen
- Lundbeck Foundation, Research Initiative on Brain Barriers and Drug Delivery, Scherfigsvej 7, 2100, Copenhagen, Denmark.,Laboratory of Neurobiology, Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 3, 9220, Aalborg, Denmark
| | - Torben Moos
- Lundbeck Foundation, Research Initiative on Brain Barriers and Drug Delivery, Scherfigsvej 7, 2100, Copenhagen, Denmark.,Laboratory of Neurobiology, Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 3, 9220, Aalborg, Denmark
| | - Hannes T Lohi
- Research Program for Molecular Neurology, Helsinki University, Haartmaninkatu 8, 00290, Helsinki, Finland
| | - Peder Madsen
- Department of Biomedicine, Faculty of Health, Aarhus University, Ole Worms Allé 3, 8000, Aarhus, Denmark
| | - Karin Lykke-Hartmann
- Department of Biomedicine, Faculty of Health, Aarhus University, Ole Worms Allé 3, 8000, Aarhus, Denmark.,Department of Clinical Genetics, Aarhus University Hospital, Brendstrupgårdsvej 21, 8200, Aarhus, Denmark.,Department of Clinical Medicine, Faculty of Health, Aarhus University, Bartholins Alle 6, 8000, Aarhus, Denmark
| | - Morten S Nielsen
- Department of Biomedicine, Faculty of Health, Aarhus University, Ole Worms Allé 3, 8000, Aarhus, Denmark. .,Lundbeck Foundation, Research Initiative on Brain Barriers and Drug Delivery, Scherfigsvej 7, 2100, Copenhagen, Denmark.
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16
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Toth AE, Nielsen MS. Analysis of the trafficking system in blood-brain barrier models by high content screening microscopy. Neural Regen Res 2018; 13:1883-1884. [PMID: 30233057 PMCID: PMC6183033 DOI: 10.4103/1673-5374.239435] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Andrea E Toth
- Department of Biomedicine, Faculty of Health, Aarhus University, Aarhus, Denmark
| | - Morten S Nielsen
- Department of Biomedicine, Faculty of Health, Aarhus University, Aarhus, Denmark
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17
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Villaseñor R, Collin L. High-resolution Confocal Imaging of the Blood-brain Barrier: Imaging, 3D Reconstruction, and Quantification of Transcytosis. J Vis Exp 2017. [PMID: 29286366 PMCID: PMC5755420 DOI: 10.3791/56407] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The blood-brain barrier (BBB) is a dynamic multicellular interface that regulates the transport of molecules between the circulation and the brain. Transcytosis across the BBB regulates the delivery of hormones, metabolites, and therapeutic antibodies to the brain parenchyma. Here, we present a protocol that combines immunofluorescence of free-floating sections with laser scanning confocal microscopy and image analysis to visualize subcellular organelles within endothelial cells at the BBB. Combining this data-set with 3D image analysis software allows for the semi-automated segmentation and quantification of capillary volume and surface area, as well as the number and intensity of intracellular organelles at the BBB. The detection of mouse endogenous immunoglobulin (IgG) within intracellular vesicles and their quantification at the BBB is used to illustrate the method. This protocol can potentially be applied to the investigation of the mechanisms controlling BBB transcytosis of different molecules in vivo.
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Affiliation(s)
- Roberto Villaseñor
- Roche Pharma Research and Early Development (pRED), Neuroimmunology, Roche Innovation Center Basel
| | - Ludovic Collin
- Roche Pharma Research and Early Development (pRED), Neuroimmunology, Roche Innovation Center Basel;
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18
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Nielsen SSE, Siupka P, Georgian A, Preston JE, Tóth AE, Yusof SR, Abbott NJ, Nielsen MS. Improved Method for the Establishment of an In Vitro Blood-Brain Barrier Model Based on Porcine Brain Endothelial Cells. J Vis Exp 2017. [PMID: 28994773 DOI: 10.3791/56277] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The aim of this protocol presents an optimized procedure for the purification and cultivation of pBECs and to establish in vitro blood-brain barrier (BBB) models based on pBECs in mono-culture (MC), MC with astrocyte-conditioned medium (ACM), and non-contact co-culture (NCC) with astrocytes of porcine or rat origin. pBECs were isolated and cultured from fragments of capillaries from the brain cortices of domestic pigs 5-6 months old. These fragments were purified by careful removal of meninges, isolation and homogenization of grey matter, filtration, enzymatic digestion, and centrifugation. To further eliminate contaminating cells, the capillary fragments were cultured with puromycin-containing medium. When 60-95% confluent, pBECs growing from the capillary fragments were passaged to permeable membrane filter inserts and established in the models. To increase barrier tightness and BBB characteristic phenotype of pBECs, the cells were treated with the following differentiation factors: membrane permeant 8-CPT-cAMP (here abbreviated cAMP), hydrocortisone, and a phosphodiesterase inhibitor, RO-20-1724 (RO). The procedure was carried out over a period of 9-11 days, and when establishing the NCC model, the astrocytes were cultured 2-8 weeks in advance. Adherence to the described procedures in the protocol has allowed the establishment of endothelial layers with highly restricted paracellular permeability, with the NCC model showing an average transendothelial electrical resistance (TEER) of 1249 ± 80 Ω cm2, and paracellular permeability (Papp) for Lucifer Yellow of 0.90 10-6 ± 0.13 10-6 cm sec-1 (mean ± SEM, n=55). Further evaluation of this pBEC phenotype showed good expression of the tight junctional proteins claudin 5, ZO-1, occludin and adherens junction protein p120 catenin. The model presented can be used for a range of studies of the BBB in health and disease and, with the highly restrictive paracellular permeability, this model is suitable for studies of transport and intracellular trafficking.
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Affiliation(s)
- Simone S E Nielsen
- Lundbeck Foundation Research Initiative on Brain Barriers and Drug Delivery, Department of Biomedicine, Aarhus University
| | - Piotr Siupka
- Lundbeck Foundation Research Initiative on Brain Barriers and Drug Delivery, Department of Biomedicine, Aarhus University
| | - Ana Georgian
- Institute of Pharmaceutical Science, King's College London
| | - Jane E Preston
- Institute of Pharmaceutical Science, King's College London
| | - Andrea E Tóth
- Lundbeck Foundation Research Initiative on Brain Barriers and Drug Delivery, Department of Biomedicine, Aarhus University
| | - Siti R Yusof
- Institute of Pharmaceutical Science, King's College London; HICoE Centre for Drug Research, Universiti Sains Malaysia
| | - N Joan Abbott
- Institute of Pharmaceutical Science, King's College London;
| | - Morten S Nielsen
- Lundbeck Foundation Research Initiative on Brain Barriers and Drug Delivery, Department of Biomedicine, Aarhus University;
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19
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Johnsen KB, Burkhart A, Melander F, Kempen PJ, Vejlebo JB, Siupka P, Nielsen MS, Andresen TL, Moos T. Targeting transferrin receptors at the blood-brain barrier improves the uptake of immunoliposomes and subsequent cargo transport into the brain parenchyma. Sci Rep 2017; 7:10396. [PMID: 28871203 PMCID: PMC5583399 DOI: 10.1038/s41598-017-11220-1] [Citation(s) in RCA: 155] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 08/16/2017] [Indexed: 01/23/2023] Open
Abstract
Drug delivery to the brain is hampered by the presence of the blood-brain barrier, which excludes most molecules from freely diffusing into the brain, and tightly regulates the active transport mechanisms that ensure sufficient delivery of nutrients to the brain parenchyma. Harnessing the possibility of delivering neuroactive drugs by way of receptors already present on the brain endothelium has been of interest for many years. The transferrin receptor is of special interest since its expression is limited to the endothelium of the brain as opposed to peripheral endothelium. Here, we investigate the possibility of delivering immunoliposomes and their encapsulated cargo to the brain via targeting of the transferrin receptor. We find that transferrin receptor-targeting increases the association between the immunoliposomes and primary endothelial cells in vitro, but that this does not correlate with increased cargo transcytosis. Furthermore, we show that the transferrin receptor-targeted immunoliposomes accumulate along the microvessels of the brains of rats, but find no evidence for transcytosis of the immunoliposome. Conversely, the increased accumulation correlated both with increased cargo uptake in the brain endothelium and subsequent cargo transport into the brain. These findings suggest that transferrin receptor-targeting is a relevant strategy of increasing drug exposure to the brain.
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Affiliation(s)
- Kasper Bendix Johnsen
- Laboratory for Neurobiology, Biomedicine, Institute of Health Science and Technology, Aalborg University, Aalborg, Denmark
- Center for Nanomedicine and Theranostics, Department of Micro- and Nanotechnology, Technical University of Denmark, Lyngby, Denmark
| | - Annette Burkhart
- Laboratory for Neurobiology, Biomedicine, Institute of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Fredrik Melander
- Center for Nanomedicine and Theranostics, Department of Micro- and Nanotechnology, Technical University of Denmark, Lyngby, Denmark
| | - Paul Joseph Kempen
- Center for Nanomedicine and Theranostics, Department of Micro- and Nanotechnology, Technical University of Denmark, Lyngby, Denmark
| | - Jonas Bruun Vejlebo
- Center for Nanomedicine and Theranostics, Department of Micro- and Nanotechnology, Technical University of Denmark, Lyngby, Denmark
| | - Piotr Siupka
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | - Thomas Lars Andresen
- Center for Nanomedicine and Theranostics, Department of Micro- and Nanotechnology, Technical University of Denmark, Lyngby, Denmark
| | - Torben Moos
- Laboratory for Neurobiology, Biomedicine, Institute of Health Science and Technology, Aalborg University, Aalborg, Denmark.
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