1
|
pH-Responsive Lipid Nanoparticles Achieve Efficient mRNA Transfection in Brain Capillary Endothelial Cells. Pharmaceutics 2022; 14:pharmaceutics14081560. [PMID: 36015185 PMCID: PMC9413996 DOI: 10.3390/pharmaceutics14081560] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 06/11/2022] [Accepted: 07/24/2022] [Indexed: 02/04/2023] Open
Abstract
The blood–brain barrier (BBB), which is comprised of brain capillary endothelial cells, plays a pivotal role in the transport of drugs from the blood to the brain. Therefore, an analysis of proteins in the endothelial cells, such as transporters and tight junction proteins, which contribute to BBB function, is important for the development of therapeutics for the treatment of brain diseases. However, gene transfection into the vascular endothelial cells of the BBB is fraught with difficulties, even in vitro. We report herein on the development of lipid nanoparticles (LNPs), in which mRNA is encapsulated in a nano-sized capsule composed of a pH-activated and reductive environment-responsive lipid-like material (ssPalm). We evaluated the efficiency of mRNA delivery into non-polarized human brain capillary endothelial cells, hCMEC/D3 cells. The ssPalm LNPs permitted marker genes (GFP) to be transferred into nearly 100% of the cells, with low toxicity in higher concentration. A proteomic analysis indicated that the ssPalm-LNP had less effect on global cell signaling pathways than a Lipofectamine MessengerMAX/GFP-encoding mRNA complex (LFN), a commercially available transfection reagent, even at higher mRNA concentrations.
Collapse
|
2
|
Gericke B, Borsdorf S, Wienböker I, Noack A, Noack S, Löscher W. Similarities and differences in the localization, trafficking, and function of P-glycoprotein in MDR1-EGFP-transduced rat versus human brain capillary endothelial cell lines. Fluids Barriers CNS 2021; 18:36. [PMID: 34344390 PMCID: PMC8330100 DOI: 10.1186/s12987-021-00266-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 06/28/2021] [Indexed: 12/24/2022] Open
Abstract
Background In vitro models based on brain capillary endothelial cells (BCECs) are among the most versatile tools in blood–brain barrier research for testing drug penetration into the brain and how this is affected by efflux transporters such as P-glycoprotein (Pgp). However, compared to freshly isolated brain capillaries or primary BCECs, the expression of Pgp in immortalized BCEC lines is markedly lower, which prompted us previously to transduce the widely used human BCEC line hCMEC/D3 with a doxycycline-inducible MDR1-EGFP fusion plasmid. The EGFP-labeled Pgp in these cells allows studying the localization and trafficking of the transporter and how these processes are affected by drug exposure. Here we used this strategy for the rat BCEC line RBE4 and performed a face-to-face comparison of RBE4 and hCMEC/D3 wild-type (WT) and MDR1-EGFP transduced cells. Methods MDR1-EGFP-transduced variants were derived from WT cells by lentiviral transduction, using an MDR1-linker-EGFP vector. Localization, trafficking, and function of Pgp were compared in WT and MDR1-EGFP transduced cell lines. Primary cultures of rat BCECs and freshly isolated rat brain capillaries were used for comparison. Results All cells exhibited typical BCEC morphology. However, significant differences were observed in the localization of Pgp in that RBE4-MDR1-EGFP cells expressed Pgp primarily at the plasma membrane, whereas in hCMEC/D3 cells, the Pgp-EGFP fusion protein was visible both at the plasma membrane and in endolysosomal vesicles. Exposure to doxorubicin increased the number of Pgp-EGFP-positive endolysosomes, indicating a lysosomotropic effect. Furthermore, lysosomal trapping of doxorubicin was observed, likely contributing to the protection of the cell nucleus from damage. In cocultures of WT and MDR1-EGFP transduced cells, intercellular Pgp-EGFP trafficking was observed in RBE4 cells as previously reported for hCMEC/D3 cells. Compared to WT cells, the MDR1-EGFP transduced cells exhibited a significantly higher expression and function of Pgp. However, the junctional tightness of WT and MDR1-EGFP transduced RBE4 and hCMEC/D3 cells was markedly lower than that of primary BCECs, excluding the use of the cell lines for studying vectorial drug transport. Conclusions The present data indicate that MDR1-EGFP transduced RBE4 cells are an interesting tool to study the biogenesis of lysosomes and Pgp-mediated lysosomal drug trapping in response to chemotherapeutic agents and other compounds at the level of the blood–brain barrier. Supplementary Information The online version contains supplementary material available at 10.1186/s12987-021-00266-z.
Collapse
Affiliation(s)
- Birthe Gericke
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, 30559, Hannover, Germany.,Center for Systems Neuroscience, Hannover, Germany
| | - Saskia Borsdorf
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, 30559, Hannover, Germany
| | - Inka Wienböker
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, 30559, Hannover, Germany.,Center for Systems Neuroscience, Hannover, Germany
| | - Andreas Noack
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, 30559, Hannover, Germany
| | - Sandra Noack
- Department of Trauma Surgery, Hannover Medical School, Hannover, Germany
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, 30559, Hannover, Germany. .,Center for Systems Neuroscience, Hannover, Germany.
| |
Collapse
|
3
|
Novel Intrinsic Mechanisms of Active Drug Extrusion at the Blood-Brain Barrier: Potential Targets for Enhancing Drug Delivery to the Brain? Pharmaceutics 2020; 12:pharmaceutics12100966. [PMID: 33066604 PMCID: PMC7602420 DOI: 10.3390/pharmaceutics12100966] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/07/2020] [Accepted: 10/08/2020] [Indexed: 12/13/2022] Open
Abstract
The blood-brain barrier (BBB) limits the pharmacotherapy of several brain disorders. In addition to the structural and metabolic characteristics of the BBB, the ATP-driven, drug efflux transporter P-glycoprotein (Pgp) is a selective gatekeeper of the BBB; thus, it is a primary hindrance to drug delivery into the brain. Here, we review the complex regulation of Pgp expression and functional activity at the BBB with an emphasis on recent studies from our laboratory. In addition to traditional processes such as transcriptional regulation and posttranscriptional or posttranslational modification of Pgp expression and functionality, novel mechanisms such as intra- and intercellular Pgp trafficking and intracellular Pgp-mediated lysosomal sequestration in BBB endothelial cells with subsequent disposal by blood neutrophils are discussed. These intrinsic mechanisms of active drug extrusion at the BBB are potential therapeutic targets that could be used to modulate P-glycoprotein activity in the treatment of brain diseases and enhance drug delivery to the brain.
Collapse
|
4
|
Kang M, Kim H, Lee TH, Huh YH, Kim YS, Park SJ, Jin JO, Lee PC, Kwak M. Highly photostable rylene-encapsulated polymeric nanoparticles for fluorescent labeling in biological system. J IND ENG CHEM 2019. [DOI: 10.1016/j.jiec.2019.08.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
5
|
Samant P, Burt TA, Zhao ZJ, Xiang L. Nanoscale photoacoustic tomography for label-free super-resolution imaging: simulation study. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-10. [PMID: 30411552 DOI: 10.1117/1.jbo.23.11.116501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/12/2018] [Indexed: 06/08/2023]
Abstract
Resolutions higher than the optical diffraction limit are often desired in the context of cellular imaging and the study of disease progression at the cellular level. However, three-dimensional super-resolution imaging without reliance on exogenous contrast agents has so far not been achieved. We present nanoscale photoacoustic tomography (nPAT), an imaging modality based on the photoacoustic effect. nPAT can achieve a dramatic improvement in the axial resolution of the photoacoustic imaging. We derive the theoretical resolution and sensitivity of nPAT and demonstrate that nPAT can achieve a maximum axial resolution of 9.2 nm. We also demonstrate that nPAT can theoretically detect smaller numbers of molecules (∼273) than conventional photoacoustic microscopy due to its ability to detect acoustic signals very close to the photoacoustic source. We simulate nPAT imaging of malaria-infected red blood cells (RBCs) using digital phantoms generated from real biological samples, showing nPAT imaging of the RBC at different stages of infection. These simulations show the potential of nPAT to nondestructively image RBCs at the nanometer resolutions for in vivo samples without the use of exogenous contrast agents. Simulations of nPAT-enabled functional imaging show that nPAT can yield insight into malarial metabolism and biocrystallization processes. We believe that the experimental realization of nPAT has important applications in biomedicine.
Collapse
Affiliation(s)
- Pratik Samant
- University of Oklahoma, Stephenson School of Biomedical Engineering, Norman, Oklahoma, United States
| | - Timothy A Burt
- University of Oklahoma, Homer L. Dodge Department of Physics and Astronomy, Norman, Oklahoma, United States
| | - Zhizhuang Joe Zhao
- University of Oklahoma Health Sciences Center, Department of Pathology, Oklahoma City, Oklahoma, United States
| | - Liangzhong Xiang
- University of Oklahoma, School of Electric and Computer Engineering, Norman, Oklahoma, United States
| |
Collapse
|
6
|
Mechanism of drug extrusion by brain endothelial cells via lysosomal drug trapping and disposal by neutrophils. Proc Natl Acad Sci U S A 2018; 115:E9590-E9599. [PMID: 30254169 PMCID: PMC6187170 DOI: 10.1073/pnas.1719642115] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Located at the apical (blood-facing) site of brain capillary endothelial cells that form the blood–brain barrier (BBB), the efflux transporter P-glycoprotein (Pgp) restricts the brain entry of various lipophilic xenobiotics, which contributes to BBB function. Pgp may become saturated if exposed to too-high drug concentrations. Here, we demonstrate a second-line defense mechanism in human brain capillary endothelial cells—that is, Pgp-mediated intracellular lysosomal drug trapping. Furthermore, we describe a mechanism of drug disposal at the BBB, which is shedding of lysosomal Pgp/substrate complexes at the apical membrane of human and porcine BBB endothelial cells and subsequent phagocytosis by neutrophils. Thus, we have discovered a fascinating mechanism of how Pgp might contribute to brain protection. The blood–brain barrier protects the brain against a variety of potentially toxic compounds. Barrier function results from tight junctions between brain capillary endothelial cells and high expression of active efflux transporters, including P-glycoprotein (Pgp), at the apical membrane of these cells. In addition to actively transporting drugs out of the cell, Pgp mediates lysosomal sequestration of chemotherapeutic drugs in cancer cells, thus contributing to drug resistance. Here, we describe that lysosomal sequestration of Pgp substrates, including doxorubicin, also occurs in human and porcine brain endothelial cells that form the blood–brain barrier. This is followed by shedding of drug-sequestering vesicular structures, which stay attached to the apical side of the plasma membrane and form aggregates (“barrier bodies”) that ultimately undergo phagocytosis by neutrophils, thus constituting an as-yet-undescribed mechanism of drug disposal. These findings introduce a mechanism that might contribute to brain protection against potentially toxic xenobiotics, including therapeutically important chemotherapeutic drugs.
Collapse
|
7
|
Bukuroshi P, Saitoh H, Magomedova L, Cummins CL, Chow EC, Li AP, Pang KS. Strategies and limitations associated with in vitro characterization of vitamin D receptor activators. Biochem Pharmacol 2018; 155:547-561. [PMID: 30028992 DOI: 10.1016/j.bcp.2018.07.015] [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: 05/01/2018] [Accepted: 07/14/2018] [Indexed: 11/26/2022]
Abstract
In vitro cell-based assays are common screening tools used for the identification of new VDR ligands. For 25-hydroxyvitamin D3 [25(OH)D3] and 1α-hydroxyvitamin D3 [1α(OH)D3], protein expressions of CYP2R1 and CYP27B1, respectively, that form the active 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3] ligand were detected in human embryonic kidney (HEK293) cells expressing the GAL4-hVDR, the human brain microvessel endothelial (hCMEC/D3) and adenocarcinoma colonic (Caco-2) cells. The impact of bioactivation enzymes was shown upon the addition of ketoconazole (10 μM KTZ), a pan-CYP inhibitor, which reduced the apparent potency of 25(OH)D3 and increased the EC50 from 272 to 608 nM in HEK293 cells. EIA assays verified that 1,25(OH)2D3 was formed and contributed to VDR activity independently of its precursors. In hCMEC/D3 cells where enzyme protein levels were lowest, changes in MDR1/P-gp expression with KTZ were minimal. In Caco-2 cells, the induction of TRPV6 (calcium channel), CYP24A1, CYP3A4, OATP1A2 and MDR1 mRNA expression was 1,25(OH)2D3 > 1α(OH)D3 > 25(OH)D3, with the magnitude of change being blunted by KTZ. Upon inclusion of KTZ in the cell-based assays, high transcriptional activities were observed for synthetic VDR activators from Teijin Pharma. Cyclopentanone derivatives: TPD-003, TPD-005, TPD-006, TPD-008 and TPD-009 (EC50s 0.06 to 67 nM, unchanged with KTZ) were found more potent over straight chain and lactone derivatives (antagonists). Most TPD compounds activated OATP1A2, CYP24A1, CYP3A4, and MDR1 (28-67%) and TRPV6 transcriptionally in Caco-2 cells. The results identified that cell-based assays with added KTZ could accurately identify new VDR activators, although these may be hypercalcemic with strong TRPV6 inducing properties.
Collapse
Affiliation(s)
- Paola Bukuroshi
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Hiroshi Saitoh
- Teijin Pharma Inc., 3-2, Asahigaoka 4-chome, Hino, Tokyo 191-8512, Japan
| | - Lilia Magomedova
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Carolyn L Cummins
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Edwin C Chow
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Albert P Li
- In Vitro ADMET Laboratories, Columbia, MD 21045, USA
| | - K Sandy Pang
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada.
| |
Collapse
|
8
|
Greenwood J, Hammarlund-Udenaes M, Jones HC, Stitt AW, Vandenbroucke RE, Romero IA, Campbell M, Fricker G, Brodin B, Manninga H, Gaillard PJ, Schwaninger M, Webster C, Wicher KB, Khrestchatisky M. Current research into brain barriers and the delivery of therapeutics for neurological diseases: a report on CNS barrier congress London, UK, 2017. Fluids Barriers CNS 2017; 14:31. [PMID: 29110676 PMCID: PMC5674735 DOI: 10.1186/s12987-017-0079-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 10/23/2017] [Indexed: 03/24/2023] Open
Abstract
This is a report on the CNS barrier congress held in London, UK, March 22–23rd 2017 and sponsored by Kisaco Research Ltd. The two 1-day sessions were chaired by John Greenwood and Margareta Hammarlund-Udenaes, respectively, and each session ended with a discussion led by the chair. Speakers consisted of invited academic researchers studying the brain barriers in relation to neurological diseases and industry researchers studying new methods to deliver therapeutics to treat neurological diseases. We include here brief reports from the speakers.
Collapse
Affiliation(s)
- John Greenwood
- Institute of Ophthalmology, University College London, London, EC1V 9EL, UK
| | | | - Hazel C Jones
- Gagle Brook House, Chesterton, Bicester, OX26 1UF, UK.
| | - Alan W Stitt
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, Northern Ireland, UK
| | - Roosmarijn E Vandenbroucke
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.,VIB-UGent Center for Inflammation Research, VIB, Ghent, Belgium
| | - Ignacio A Romero
- School of Life, Health and Chemical Sciences, Open University, Milton Keynes, UK
| | - Matthew Campbell
- Smurfit Institute of Genetics, Lincoln Place Gate, Trinity College Dublin, Dublin 2, Ireland
| | - 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
| | - Heiko Manninga
- NEUWAY Pharma GmbH, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany
| | | | - Markus Schwaninger
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Lübeck, Germany
| | - Carl Webster
- Antibody Discovery and Protein Engineering, MedImmune, Cambridge, UK
| | | | - Michel Khrestchatisky
- CNRS, NICN, Aix Marseille Univ, Marseille, France.,Vect-Horus, Faculte de Medecine Nord, 51 Boulevard Pierre Dramard, Marseille, France
| |
Collapse
|
9
|
Intercellular transfer of P-glycoprotein in human blood-brain barrier endothelial cells is increased by histone deacetylase inhibitors. Sci Rep 2016; 6:29253. [PMID: 27375084 PMCID: PMC4931680 DOI: 10.1038/srep29253] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 06/14/2016] [Indexed: 12/14/2022] Open
Abstract
The blood–brain barrier (BBB) controls the entry of compounds into the brain, thereby regulating brain homeostasis. Efflux transporters such as P-glycoprotein (Pgp) significantly contribute to BBB function. Multiple signaling pathways modulate the expression and activity of Pgp in response to xenobiotics and disease. A non-genetic way of intercellular transfer of Pgp occurs in cancer cells, but whether this also occurs in non-cancer cells such as endothelial cells that form the BBB is not known. A human brain endothelial cell line (hCMEC/D3) was used to study whether cell-to-cell Pgp transfer occurs during co-culturing with Pgp-EGFP expressing hCMEC/D3 cells. The Pgp-EGFP fusion protein was transferred from donor to recipient cells by cell-to-cell contact and Pgp-EGFP enriched vesicles, which were exocytosed by donor cells and endocytosed by adherent recipient cells. Flow cytometry experiments with the Pgp substrate eFLUXX-ID Gold demonstrated that the transferred Pgp is functional in the recipient cells. Exposure of the donor cells with inhibitors of histone deacetylases (HDACs) resulted in an enhanced intercellular Pgp transfer. Non-genetic transfer of a resistance phenotype and its regulation by HDACs is a novel mechanism of altering BBB functionality. This mechanism may have important implications for understanding drug-induced alterations in Pgp expression and activity.
Collapse
|
10
|
Franek M, Suchánková J, Sehnalová P, Krejčí J, Legartová S, Kozubek S, Večeřa J, Sorokin DV, Bártová E. Advanced Image Acquisition and Analytical Techniques for Studies of Living Cells and Tissue Sections. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2016; 22:326-341. [PMID: 26903193 DOI: 10.1017/s1431927616000052] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Studies on fixed samples or genome-wide analyses of nuclear processes are useful for generating snapshots of a cell population at a particular time point. However, these experimental approaches do not provide information at the single-cell level. Genome-wide studies cannot assess variability between individual cells that are cultured in vitro or originate from different pathological stages. Immunohistochemistry and immunofluorescence are fundamental experimental approaches in clinical laboratories and are also widely used in basic research. However, the fixation procedure may generate artifacts and prevents monitoring of the dynamics of nuclear processes. Therefore, live-cell imaging is critical for studying the kinetics of basic nuclear events, such as DNA replication, transcription, splicing, and DNA repair. This review is focused on the advanced microscopy analyses of the cells, with a particular focus on live cells. We note some methodological innovations and new options for microscope systems that can also be used to study tissue sections. Cornerstone methods for the biophysical research of living cells, such as fluorescence recovery after photobleaching and fluorescence resonance energy transfer, are also discussed, as are studies on the effects of radiation at the individual cellular level.
Collapse
Affiliation(s)
- Michal Franek
- Institute of Biophysics,Academy of Sciences of the Czech Republic,v.v.i.,Královopolská 135,612 65 Brno,Czech Republic
| | - Jana Suchánková
- Institute of Biophysics,Academy of Sciences of the Czech Republic,v.v.i.,Královopolská 135,612 65 Brno,Czech Republic
| | - Petra Sehnalová
- Institute of Biophysics,Academy of Sciences of the Czech Republic,v.v.i.,Královopolská 135,612 65 Brno,Czech Republic
| | - Jana Krejčí
- Institute of Biophysics,Academy of Sciences of the Czech Republic,v.v.i.,Královopolská 135,612 65 Brno,Czech Republic
| | - Soňa Legartová
- Institute of Biophysics,Academy of Sciences of the Czech Republic,v.v.i.,Královopolská 135,612 65 Brno,Czech Republic
| | - Stanislav Kozubek
- Institute of Biophysics,Academy of Sciences of the Czech Republic,v.v.i.,Královopolská 135,612 65 Brno,Czech Republic
| | | | | | - Eva Bártová
- Institute of Biophysics,Academy of Sciences of the Czech Republic,v.v.i.,Královopolská 135,612 65 Brno,Czech Republic
| |
Collapse
|
11
|
Worzfeld T, Schwaninger M. Apicobasal polarity of brain endothelial cells. J Cereb Blood Flow Metab 2016; 36:340-62. [PMID: 26661193 PMCID: PMC4759676 DOI: 10.1177/0271678x15608644] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 09/07/2015] [Indexed: 01/24/2023]
Abstract
Normal brain homeostasis depends on the integrity of the blood-brain barrier that controls the access of nutrients, humoral factors, and immune cells to the CNS. The blood-brain barrier is composed mainly of brain endothelial cells. Forming the interface between two compartments, they are highly polarized. Apical/luminal and basolateral/abluminal membranes differ in their lipid and (glyco-)protein composition, allowing brain endothelial cells to secrete or transport soluble factors in a polarized manner and to maintain blood flow. Here, we summarize the basic concepts of apicobasal cell polarity in brain endothelial cells. To address potential molecular mechanisms underlying apicobasal polarity in brain endothelial cells, we draw on investigations in epithelial cells and discuss how polarity may go awry in neurological diseases.
Collapse
Affiliation(s)
- Thomas Worzfeld
- Institute of Pharmacology, Biochemical-Pharmacological Center (BPC), University of Marburg, Marburg, Germany Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Markus Schwaninger
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Lübeck, Germany German Research Centre for Cardiovascular Research, DZHK, Lübeck, Germany
| |
Collapse
|
12
|
Rudashevskaya EL, Stockner T, Trauner M, Freissmuth M, Chiba P. Pharmacological correction of misfolding of ABC proteins. DRUG DISCOVERY TODAY. TECHNOLOGIES 2015; 12:e87-94. [PMID: 25027379 PMCID: PMC4039138 DOI: 10.1016/j.ddtec.2014.03.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The endoplasmic reticulum (ER) quality control system distinguishes between correctly and incorrectly folded proteins to prevent processing of aberrantly folded conformations along the secretory pathway. Non-synonymous mutations can lead to misfolding of ABC proteins and associated disease phenotypes. Specific phenotypes may at least partially be corrected by small molecules, so-called pharmacological chaperones. Screening for folding correctors is expected to open an avenue for treatment of diseases such as cystic fibrosis and intrahepatic cholestasis.
Collapse
Affiliation(s)
- Elena L Rudashevskaya
- Institute of Medical Chemistry, Medical University of Vienna, Waehringerstrasse 10, Vienna, Austria
| | - Thomas Stockner
- Institute of Pharmacology, Medical University of Vienna, Waehringerstrasse 13, Vienna, Austria
| | - Michael Trauner
- Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Waehringer Guertel 18-20, Austria
| | - Michael Freissmuth
- Institute of Pharmacology, Medical University of Vienna, Waehringerstrasse 13, Vienna, Austria
| | - Peter Chiba
- Institute of Medical Chemistry, Medical University of Vienna, Waehringerstrasse 10, Vienna, Austria
| |
Collapse
|
13
|
Schubert V, Weisshart K. Abundance and distribution of RNA polymerase II in Arabidopsis interphase nuclei. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:1687-98. [PMID: 25740920 PMCID: PMC4357323 DOI: 10.1093/jxb/erv091] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
RNA polymerase II (RNAPII) is responsible for the transcription of most eukaryotic protein-coding genes. Analysing the topological distribution and quantification of RNAPII can contribute to understanding its function in interphase nuclei. Previously it was shown that RNAPII molecules in plant nuclei form reticulate structures within euchromatin of differentiated Arabidopsis thaliana nuclei rather than being organized in distinct 'transcription factories' as observed in mammalian nuclei. Immunosignal intensity measurements based on specific antibody labelling in maximum intensity projections of image stacks acquired by structured illumination microscopy (SIM) suggested a relative proportional increase of RNAPII in endopolyploid plant nuclei. Here, photoactivated localization microscopy (PALM) was applied to determine the absolute number and distribution of active and inactive RNAPII molecules in differentiated A. thaliana nuclei. The proportional increase of RNAPII during endopolyploidization is confirmed, but it is also shown that PALM measurements are more reliable than those based on SIM in terms of quantification. The single molecule localization results show that, although RNAPII molecules are globally dispersed within plant euchromatin, they also aggregate within smaller distances as described for mammalian transcription factories.
Collapse
Affiliation(s)
- Veit Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, D-06466 Stadt Seeland, Germany
| | | |
Collapse
|
14
|
Szczurek AT, Prakash K, Lee HK, Żurek-Biesiada DJ, Best G, Hagmann M, Dobrucki JW, Cremer C, Birk U. Single molecule localization microscopy of the distribution of chromatin using Hoechst and DAPI fluorescent probes. Nucleus 2014; 5:331-40. [PMID: 25482122 PMCID: PMC4152347 DOI: 10.4161/nucl.29564] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 06/06/2014] [Accepted: 06/12/2014] [Indexed: 12/12/2022] Open
Abstract
Several approaches have been described to fluorescently label and image DNA and chromatin in situ on the single-molecule level. These superresolution microscopy techniques are based on detecting optically isolated, fluorescently tagged anti-histone antibodies, fluorescently labeled DNA precursor analogs, or fluorescent dyes bound to DNA. Presently they suffer from various drawbacks such as low labeling efficiency or interference with DNA structure. In this report, we demonstrate that DNA minor groove binding dyes, such as Hoechst 33258, Hoechst 33342, and DAPI, can be effectively employed in single molecule localization microscopy (SMLM) with high optical and structural resolution. Upon illumination with low intensity 405 nm light, a small subpopulation of these molecules stochastically undergoes photoconversion from the original blue-emitting form to a green-emitting form. Using a 491 nm laser excitation, fluorescence of these green-emitting, optically isolated molecules was registered until "bleached". This procedure facilitated substantially the optical isolation and localization of large numbers of individual dye molecules bound to DNA in situ, in nuclei of fixed mammalian cells, or in mitotic chromosomes, and enabled the reconstruction of high-quality DNA density maps. We anticipate that this approach will provide new insights into DNA replication, DNA repair, gene transcription, and other nuclear processes.
Collapse
Affiliation(s)
| | - Kirti Prakash
- Institute of Molecular Biology; Mainz, Germany
- Institute for Pharmacy and Molecular Biotechnology; University of Heidelberg; Heidelberg, Germany
| | - Hyun-Keun Lee
- Institute of Molecular Biology; Mainz, Germany
- Department of Physics; University of Mainz; Mainz, Germany
| | | | - Gerrit Best
- Kirchhoff Institute for Physics; University of Heidelberg; Heidelberg, Germany
- University Hospital Heidelberg; University of Heidelberg; Heidelberg, Germany
| | - Martin Hagmann
- Kirchhoff Institute for Physics; University of Heidelberg; Heidelberg, Germany
- University Hospital Heidelberg; University of Heidelberg; Heidelberg, Germany
| | - Jurek W Dobrucki
- Faculty of Biochemistry, Biophysics, and Biotechnology; Jagiellonian University; Kraków, Poland
| | - Christoph Cremer
- Institute of Molecular Biology; Mainz, Germany
- Institute for Pharmacy and Molecular Biotechnology; University of Heidelberg; Heidelberg, Germany
- Department of Physics; University of Mainz; Mainz, Germany
- Kirchhoff Institute for Physics; University of Heidelberg; Heidelberg, Germany
| | - Udo Birk
- Institute of Molecular Biology; Mainz, Germany
- Department of Physics; University of Mainz; Mainz, Germany
- Kirchhoff Institute for Physics; University of Heidelberg; Heidelberg, Germany
| |
Collapse
|
15
|
Application perspectives of localization microscopy in virology. Histochem Cell Biol 2014; 142:43-59. [DOI: 10.1007/s00418-014-1203-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/20/2014] [Indexed: 01/07/2023]
|
16
|
Notelaers K, Rocha S, Paesen R, Swinnen N, Vangindertael J, Meier JC, Rigo JM, Ameloot M, Hofkens J. Membrane distribution of the glycine receptor α3 studied by optical super-resolution microscopy. Histochem Cell Biol 2014; 142:79-90. [PMID: 24553792 DOI: 10.1007/s00418-014-1197-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2014] [Indexed: 11/24/2022]
Abstract
In this study, the effect of glycine receptor (GlyR) α3 alternative RNA splicing on the distribution of receptors in the membrane of human embryonic kidney 293 cells is investigated using optical super-resolution microscopy. Direct stochastic optical reconstruction microscopy is used to image both α3K and α3L splice variants individually and together using single- and dual-color imaging. Pair correlation analysis is used to extract quantitative measures from the resulting images. Autocorrelation analysis of the individually expressed variants reveals clustering of both variants, yet with differing properties. The cluster size is increased for α3L compared to α3K (mean radius 92 ± 4 and 56 ± 3 nm, respectively), yet an even bigger difference is found in the cluster density (9,870 ± 1,433 and 1,747 ± 200 μm(-2), respectively). Furthermore, cross-correlation analysis revealed that upon co-expression, clusters colocalize on the same spatial scales as for individually expressed receptors (mean co-cluster radius 94 ± 6 nm). These results demonstrate that RNA splicing determines GlyR α3 membrane distribution, which has consequences for neuronal GlyR physiology and function.
Collapse
Affiliation(s)
- Kristof Notelaers
- Biomedical Research Institute, Hasselt University and School of Life Sciences, Transnational University Limburg, Agoralaan Gebouw C, 3590, Diepenbeek, Belgium
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Noack A, Noack S, Hoffmann A, Maalouf K, Buettner M, Couraud PO, Romero IA, Weksler B, Alms D, Römermann K, Naim HY, Löscher W. Drug-induced trafficking of p-glycoprotein in human brain capillary endothelial cells as demonstrated by exposure to mitomycin C. PLoS One 2014; 9:e88154. [PMID: 24505408 PMCID: PMC3913777 DOI: 10.1371/journal.pone.0088154] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 01/05/2014] [Indexed: 02/07/2023] Open
Abstract
P-glycoprotein (Pgp; ABCB1/MDR1) is a major efflux transporter at the blood-brain barrier (BBB), restricting the penetration of various compounds. In other tissues, trafficking of Pgp from subcellular stores to the cell surface has been demonstrated and may constitute a rapid way of the cell to respond to toxic compounds by functional membrane insertion of the transporter. It is not known whether drug-induced Pgp trafficking also occurs in brain capillary endothelial cells that form the BBB. In this study, trafficking of Pgp was investigated in human brain capillary endothelial cells (hCMEC/D3) that were stably transfected with a doxycycline-inducible MDR1-EGFP fusion plasmid. In the presence of doxycycline, these cells exhibited a 15-fold increase in Pgp-EGFP fusion protein expression, which was associated with an increased efflux of the Pgp substrate rhodamine 123 (Rho123). The chemotherapeutic agent mitomycin C (MMC) was used to study drug-induced trafficking of Pgp. Confocal fluorescence microscopy of single hCMEC/D3-MDR1-EGFP cells revealed that Pgp redistribution from intracellular pools to the cell surface occurred within 2 h of MMC exposure. Pgp-EGFP exhibited a punctuate pattern at the cell surface compatible with concentrated regions of the fusion protein in membrane microdomains, i.e., lipid rafts, which was confirmed by Western blot analysis of biotinylated cell surface proteins in Lubrol-resistant membranes. MMC exposure also increased the functionality of Pgp as assessed in three functional assays with Pgp substrates (Rho123, eFluxx-ID Gold, calcein-AM). However, this increase occurred with some delay after the increased Pgp expression and coincided with the release of Pgp from the Lubrol-resistant membrane complexes. Disrupting rafts by depleting the membrane of cholesterol increased the functionality of Pgp. Our data present the first direct evidence of drug-induced Pgp trafficking at the human BBB and indicate that Pgp has to be released from lipid rafts to gain its full functionality.
Collapse
Affiliation(s)
- Andreas Noack
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Sandra Noack
- Department of Trauma Surgery, Hannover Medical School, Hannover, Germany
| | - Andrea Hoffmann
- Department of Trauma Surgery, Hannover Medical School, Hannover, Germany
| | - Katia Maalouf
- Department of Physiological Chemistry, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Manuela Buettner
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
| | - Pierre-Olivier Couraud
- INSERM, U1016, Institut Cochin, Paris, France
- Centre National de la Recherche Scientifique (CNRS), UMR8104, Paris, France
- Université René Descartes, Paris, France
| | - Ignacio A. Romero
- Department of Biological Sciences, The Open University, Milton Keynes, United Kingdom
| | - Babette Weksler
- Weill Medical College of Cornell University, New York, New York, United States of America
| | - Dana Alms
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Kerstin Römermann
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Hassan Y. Naim
- Department of Physiological Chemistry, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
- * E-mail:
| |
Collapse
|
18
|
|
19
|
Tachikawa M, Uchida Y, Ohtsuki S, Terasaki T. Recent Progress in Blood–Brain Barrier and Blood–CSF Barrier Transport Research: Pharmaceutical Relevance for Drug Delivery to the Brain. DRUG DELIVERY TO THE BRAIN 2014. [DOI: 10.1007/978-1-4614-9105-7_2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
20
|
Functional Expression of Drug Transporters in Glial Cells. PHARMACOLOGY OF THE BLOOD BRAIN BARRIER: TARGETING CNS DISORDERS 2014; 71:45-111. [DOI: 10.1016/bs.apha.2014.06.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|