51
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Trepat X, Puig F, Gavara N, Fredberg JJ, Farre R, Navajas D. Effect of stretch on structural integrity and micromechanics of human alveolar epithelial cell monolayers exposed to thrombin. Am J Physiol Lung Cell Mol Physiol 2006; 290:L1104-10. [PMID: 16399786 DOI: 10.1152/ajplung.00436.2005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Alveolar epithelial cells in patients with acute lung injury subjected to mechanical ventilation are exposed to increased procoagulant activity and mechanical strain. Thrombin induces epithelial cell stiffening, contraction, and cytoskeletal remodeling, potentially compromising the balance of forces at the alveolar epithelium during cell stretching. This balance can be further compromised by the loss of integrity of cell-cell junctions in the injured epithelium. The aim of this work was to study the effect of stretch on the structural integrity and micromechanics of human alveolar epithelial cell monolayers exposed to thrombin. Confluent and subconfluent cells (A549) were cultured on collagen-coated elastic substrates. After exposure to thrombin (0.5 U/ml), a stepwise cell stretch (20%) was applied with a vacuum-driven system mounted on an inverted microscope. The structural integrity of the cell monolayers was assessed by comparing intercellular and intracellular strains within the monolayer. Strain was measured by tracking beads tightly bound to the cell surface. Simultaneously, cell viscoelasticity was measured using optical magnetic twisting cytometry. In confluent cells, thrombin did not induce significant changes in transmission of strain from the substrate to overlying cells. By contrast, thrombin dramatically impaired the ability of subconfluent cells to follow imposed substrate deformation. Upon substrate unstretching, thrombin-treated subconfluent cells exhibited compressive strain (9%). Stretch increased stiffness (56-62%) and decreased cell hysteresivity (13-22%) of vehicle cells. By contrast, stretch did not increase stiffness of thrombin-treated cells, suggesting disruption of cytoskeletal structures. Our findings suggest that thrombin could exacerbate epithelial barrier dysfunction in injured lungs subjected to mechanical ventilation.
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Affiliation(s)
- Xavier Trepat
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina, Casanova 143, 08036 Barcelona, Spain
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52
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Capetandes A, Horne NS, Frieri M. Dermatophagoides extract-treated confluent type II epithelial cells (cA549) and human lung mesenchymal cell growth. Ann Allergy Asthma Immunol 2005; 95:381-8. [PMID: 16279569 DOI: 10.1016/s1081-1206(10)61157-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND Chronic severe persistent asthma is associated with damaged epithelial cells with discontinuous tight junctions that contribute to dysregulated fibroblast and endothelial cell (mesenchymal) growth. Dermatophagoides species-derived proteases have been shown to cause damage to epithelial cell tight junctions. OBJECTIVE To determine whether Dermatophagoides species can stimulate confluent A549 (cA549), a cell type with discontinuous tight junctions that approximate differentiated type II cells, to undergo altered growth and secrete putative soluble factors that affect the growth of human lung fibroblasts and microvascular endothelial cells. METHODS Dialyzed Dermatophagoides pteronyssinus or Dermatophagoides farinae extracts (0, 300, 600, and 1000 AU/mL) were cultured with and without cA549 in serum-free media for 24 hours. After changes in cA549 growth were recorded, conditioned media from extracts with cA549 (CM) and without cA549 (control media [CTLM]) were transferred to fibroblasts and endothelial cells for 24 hours. Fibroblast and endothelial cell growth responses to CM and CTLM were observed and measured. RESULTS All conditions showed greater than 95% cell viability. Confluent A549 showed dose-dependent growth changes characterized by increased aggregation when incubated with 300, 600, and 1000 AU/mL of D pteronyssinus in serum-free media relative to control. The CM, but not the CTLM, induced dose-dependent aggregation by fibroblasts and endothelial cells. Fibroblasts also showed decreased adhesion when incubated with CM. Dermatophagoides farinae-treated cA549 showed similar but weaker results. The use of serum, boiled CM, or boiled extract inhibited these findings. CONCLUSIONS Dialyzed Dermatophagoides species extracts altered cA549 growth and stimulated the secretion of factors that dysregulate mesenchymal cell growth in vitro.
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Affiliation(s)
- Anthony Capetandes
- Division of Allergy Immunology and Clinical Immunopathology, Department of Medicine, Nassau University Medical Center, East Meadow, New York 11554, USA
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53
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Adam E, Hansen KK, Astudillo Fernandez O, Astudillo OF, Coulon L, Bex F, Duhant X, Jaumotte E, Hollenberg MD, Jacquet A. The house dust mite allergen Der p 1, unlike Der p 3, stimulates the expression of interleukin-8 in human airway epithelial cells via a proteinase-activated receptor-2-independent mechanism. J Biol Chem 2005; 281:6910-23. [PMID: 16293628 DOI: 10.1074/jbc.m507140200] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We investigated and compared the mechanisms by which two dust mite proteolytic allergens, Der p 1 and Der p 3, and a peptide agonist of proteinase-activated receptor 2 (PAR(2)AP) trigger interleukin (IL)-8 release from human pulmonary epithelial cells (A549). Although all three stimuli tested induced the up-regulation of IL-8 (mRNA and protein), the Der p 1-mediated signaling events did not exactly match those induced by PAR(2)AP and Der p 3. First, Der p 1 was less effective in stimulating IL-8 gene transcriptional activity than PAR(2)AP and Der p 3. Second, Der p 1-mediated IL-8 expression was mainly dependent on NF-kappaB, whereas Der p 3 and PAR(2)AP regulated IL-8 expression through the activation of both NF-kappaB and AP-1. Third, although all three MAP kinases, ERK1/2, p38, and JNK, were activated, Der p 1 induced IL-8 release exclusively via the ERK1/2 signaling pathway, whereas PAR(2)AP and Der p 3 also involved the other kinases. Fourth, in HeLa cells, Der p 1 was able to up-regulate IL-8 secretion independent of PAR(2) expression, and in contrast with PAR(2)AP and Der p 3, Der p 1 was unable to affect calcium signaling via PAR(2) in PAR(2)-expressing KNRK cells. Finally, cleavage by Der p 1 of a synthetic peptide representing the N-terminal activation-cleavage site of PAR(2) did not release a high potency activator of PAR(2) as does Der p 3. We conclude that Der p 1 (but not Der p 3)-induced IL-8 production in A549 epithelial cells is independent of PAR(2) activation.
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MESH Headings
- Animals
- Antigens, Dermatophagoides/biosynthesis
- Arthropod Proteins
- Base Sequence
- Binding Sites
- Blotting, Western
- Calcium/metabolism
- Calcium Signaling
- Cell Line
- Cell Line, Tumor
- Cloning, Molecular
- Cysteine Endopeptidases
- Dose-Response Relationship, Drug
- Electrophoresis, Polyacrylamide Gel
- Enzyme Inhibitors/pharmacology
- Epithelial Cells/metabolism
- HeLa Cells
- Humans
- Hydrolysis
- Interleukin-8/biosynthesis
- Interleukin-8/metabolism
- Kidney/metabolism
- MAP Kinase Signaling System
- Molecular Sequence Data
- Mutation
- NF-kappa B/metabolism
- Peptides/chemistry
- Polymerase Chain Reaction
- Protein Binding
- RNA, Messenger/metabolism
- Rats
- Receptor, PAR-2/chemistry
- Receptor, PAR-2/metabolism
- Recombinant Proteins/chemistry
- Reverse Transcriptase Polymerase Chain Reaction
- Serine Endopeptidases
- Time Factors
- Trachea/metabolism
- Transcription Factor AP-1/chemistry
- Transcription, Genetic
- Transcriptional Activation
- Transfection
- Trypsin/pharmacology
- p38 Mitogen-Activated Protein Kinases/metabolism
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Affiliation(s)
- Emmanuelle Adam
- Department of Applied Genetics, Institut de Biologie et de Médecine Moléculaires, Université Libre de Bruxelles, B-6041 Gosselies, Belgium
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54
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Sehgal N, Custovic A, Woodcock A. Potential roles in rhinitis for protease and other enzymatic activities of allergens. Curr Allergy Asthma Rep 2005; 5:221-6. [PMID: 15842960 DOI: 10.1007/s11882-005-0041-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Exposure to airborne pollen, fungal allergens, and dust mite allergens is associated with the development of allergic rhinitis. Biologic function of allergens is considered to be a key determinant for allergenicity, and many clinically important allergens have been shown to possess enzymatic activity. It is proposed that by enabling allergens to breach the integrity of the airway epithelial barrier, proteolytic activity plays an adjuvant pro-allergic role influencing immunogenicity. In this review, current evidence regarding enzymatic activity of aeroallergens is described, and the potential role of aeroallergens in allergic rhinitis is discussed.
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Affiliation(s)
- Nita Sehgal
- North West Lung Centre, Wythenshawe Hospital, Southmoor Road, Manchester M23 9LT, UK.
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55
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Manford F, Tronde A, Jeppsson AB, Patel N, Johansson F, Forbes B. Drug permeability in 16HBE14o- airway cell layers correlates with absorption from the isolated perfused rat lung. Eur J Pharm Sci 2005; 26:414-20. [PMID: 16153810 DOI: 10.1016/j.ejps.2005.07.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2004] [Revised: 05/19/2005] [Accepted: 07/27/2005] [Indexed: 11/25/2022]
Abstract
The permeability of the lung is critical in determining the disposition of inhaled drugs and the respiratory epithelium provides the main physical barrier to drug absorption. The 16HBE14o- human bronchial epithelial cell line has been developed recently as a model of the airway epithelium. In this study, the transport of 10 low molecular weight compounds was measured in the 16HBE14o- cell layers, with apical to basolateral (absorptive) apparent permeability coefficients (P(app)) ranging from 0.4 x 10(-6)cms(-1) for Tyr-D-Arg-Phe-Phe-NH(2) to 25.2x10(-6)cms(-1) for metoprolol. Permeability in 16HBE14o- cells was found to correlate with previously reported P(app) in Caco-2 cells and absorption rates in the isolated perfused rat lung (k(a,lung)) and the rat lung in vivo (k(a,in vivo)). Log linear relationships were established between P(app) in 16HBE14o- cells and P(app) in Caco-2 cells (r(2)=0.82), k(a,lung) (r(2)=0.78) and k(a,in vivo) (r(2)=0.68). The findings suggest that permeability in 16HBE14o- cells may be useful to predict the permeability of compounds in the lung, although no advantage of using the organ-specific cell line 16HBE14o- compared to Caco-2 cells was found in this study.
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Affiliation(s)
- Fergus Manford
- King's College London, Pharmaceutical Science Research Division, 150 Stamford Street, London SE1 9NH, UK
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56
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Geys J, Coenegrachts L, Vercammen J, Engelborghs Y, Nemmar A, Nemery B, Hoet PHM. In vitro study of the pulmonary translocation of nanoparticles: a preliminary study. Toxicol Lett 2005; 160:218-26. [PMID: 16137845 DOI: 10.1016/j.toxlet.2005.07.005] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2005] [Revised: 07/13/2005] [Accepted: 07/13/2005] [Indexed: 11/25/2022]
Abstract
Recent studies indicate that inhaled ultrafine particles can pass into the circulation. To study this translocation in an in vitro model three types of pulmonary epithelial cells were examined. The integrity of the cell monolayer was verified by measuring the transepithelial electrical resistance (TEER) and passage of sodium fluorescein. TEER was too low in A549 cells. In these preliminary experiments, TEER values of 1007+/-300 and 348+/-62 Omega cm2 were reached for the Calu-3 cell line, using permeable membranes of 0.4 and 3 microm pore size, respectively. Growing primary rat type II pneumocytes on 0.4 microm pores, a TEER value of 241+/-90 Omega cm2 was reached on day 5; on 3 microm pores, no acceptable high TEER value was obtained. Translocation studies were done using 46 nm fluorescent polystyrene particles. When incubating polystyrene particles on membranes without a cellular monolayer, significant translocation was only observed using 3 microm pores: 67.5% and 52.7% for carboxyl- and amine-modified particles, respectively. Only the Calu-3 cell line was used in an initial experiment to investigate the translocation: on 0.4 microm pores no translocation was observed, on 3 microm pores approximately 6% translocation was observed both for carboxyl- and amine-modified particles.
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Affiliation(s)
- J Geys
- Laboratory of Pneumology, Unit of Lung Toxicology, K.U. Leuven, Herestraat 49, Leuven 3000, Belgium
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57
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Steimer A, Haltner E, Lehr CM. Cell culture models of the respiratory tract relevant to pulmonary drug delivery. ACTA ACUST UNITED AC 2005; 18:137-82. [PMID: 15966771 DOI: 10.1089/jam.2005.18.137] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The respiratory tract holds promise as an alternative site of drug delivery due to fast absorption and rapid onset of drug action, with avoidance of hepatic and intestinal first-pass metabolism as an additional benefit compared to oral drug delivery. At present, the pharmaceutical industry increasingly relies on appropriate in vitro models for the faster evaluation of drug absorption and metabolism as an alternative to animal testing. This article reviews the various existing cell culture systems that may be applied as in vitro models of the human air-blood barrier, for instance, in order to enable the screening of large numbers of new drug candidates at low cost with high reliability and within a short time span. Apart from such screening, cell culture-based in vitro systems may also contribute to improve our understanding of the mechanisms of drug transport across such epithelial tissues, and the mechanisms of action how advanced drug carriers, such as nanoparticles or liposomes, can help to overcome these barriers. After all, the increasing use and acceptance of such in vitro models may lead to a significant acceleration of the drug development process by facilitating the progress into clinical studies and product registration.
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Affiliation(s)
- A Steimer
- Across Barriers GmbH, Department R&D Cell & Tissue Based Systems, Science Park Saar, Saarbrücken, Germany
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58
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Kim S, Schein AJ, Nadel JA. E-cadherin promotes EGFR-mediated cell differentiation and MUC5AC mucin expression in cultured human airway epithelial cells. Am J Physiol Lung Cell Mol Physiol 2005; 289:L1049-60. [PMID: 16055478 DOI: 10.1152/ajplung.00388.2004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
In previous work, we showed that epidermal growth factor receptor (EGFR) activation causes mucin expression in airway epithelium in vivo and in human NCI-H292 airway epithelial cells and normal human bronchial epithelial (NHBE) cells in vitro. Here we show that the cell surface adhesion molecule, E-cadherin, promotes EGFR-mediated mucin production in NCI-H292 cells in a cell density- and cell cycle-dependent fashion. The addition of the EGFR ligand, transforming growth factor (TGF)-alpha, increased MUC5AC protein expression markedly in dense, but not in sparse, cultures. MUC5AC-positive cells in dense cultures contained 2 N DNA content and did not incorporate bromodeoxyuridine, suggesting that they develop via cell differentiation and that a surface molecule involved in cell-cell contact is important for EGFR-mediated mucin production. In support of this hypothesis, in dense cultures of NCI-H292 cells and in NHBE cells at air-liquid interface, blockade of E-cadherin-mediated cell-cell contacts decreased EGFR-dependent mucin production. E-cadherin blockade also increased EGFR-dependent cell proliferation and TGF-alpha-induced EGFR tyrosine phosphorylation in dense cultures of NCI-H292 cells, suggesting that E-cadherin promotes EGFR-dependent mucin production and inhibits EGFR-dependent cell proliferation via modulation of EGFR phosphotyrosine levels. Furthermore, in dense cultures, E-cadherin blockade decreased the rate of EGFR tyrosine dephosphorylation, implicating an E-cadherin-dependent protein tyrosine phosphatase in EGFR dephosphorylation. Thus E-cadherin promotes EGFR-mediated cell differentiation and MUC5AC production, and our results suggest that this occurs via a pathway involving protein tyrosine phosphatase-dependent EGFR dephosphorylation.
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Affiliation(s)
- Suil Kim
- Cardiovascular Research Institute, Box 0130, University of California-San Francisco, San Francisco, CA 94143-0130, USA
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59
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Forbes B, Ehrhardt C. Human respiratory epithelial cell culture for drug delivery applications. Eur J Pharm Biopharm 2005; 60:193-205. [PMID: 15939233 DOI: 10.1016/j.ejpb.2005.02.010] [Citation(s) in RCA: 228] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2004] [Revised: 02/01/2005] [Accepted: 02/02/2005] [Indexed: 11/24/2022]
Abstract
Recent developments in delivering drugs to the lung are driving the need for in vitro methods to evaluate the fate of inhaled medicines. Constraints on experimentation using animals have promoted the use of human respiratory epithelial cell cultures to model the absorption barrier of the lung; with two airway cell lines, 16HBE14o- and Calu-3, and primary cultured human alveolar type I-like cells (hAEpC) gaining prominence. These in vitro models develop permeability properties which are comparable to those reported for native lung epithelia. This is in contrast to the high permeability of the A549 human alveolar cell line, which is unsuitable for use in drug permeability experiments. Tabulation of apparent permeability coefficients (Papp) of compounds measured in 'absorptive' and 'secretory' directions reveals that fewer compounds (< 15) have been evaluated in 16HBE14o- cells and hAEpC compared to Calu-3 cells (> 50). Vectorial (asymmetric) transport of compounds is reported in the three cell types with P-glycoprotein, the most studied transport mechanism, being reported in all. Progress is being made towards in vitro-in vivo-correlation for pulmonary absorption and in the use of cultured respiratory cells to evaluate drug metabolism, toxicity and targeting strategies. In summary, methods for the culture of human respiratory epithelial cell layers have been established and data regarding their permeability characteristics and suitability to model the lung is becoming available. Discerning the circumstances under which the use of human respiratory cell models will be essential, or offers advantages over non-organ, non-species specific cell models, is the next challenge.
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Affiliation(s)
- Ben Forbes
- Pharmaceutical Sciences Research Division, King's College London, London, UK.
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60
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Deszcz L, Gaudernak E, Kuechler E, Seipelt J. Apoptotic events induced by human rhinovirus infection. J Gen Virol 2005; 86:1379-1389. [PMID: 15831950 DOI: 10.1099/vir.0.80754-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
HeLa and 16HBE14o(-) bronchial epithelium cells infected with human rhinovirus serotype 14 (HRV14) were found to exhibit typical apoptotic morphological alterations, such as cell contraction and nuclear condensation. These events coincided with high-molecular-weight DNA fragmentation, activation of caspase-9 and caspase-3 and poly(ADP-ribose) polymerase cleavage. Caspase activation was preceded by cytochrome c translocation from the mitochondria to the cytoplasm, indicating that apoptosis caused by HRV14 infection was triggered predominantly via the mitochondrial pathway. Apoptosis did not affect HRV14 replication per se, but it facilitated the release of newly formed virus from cells. As apoptosis was fully induced at the time of maximal accumulation of progeny HRV14, it is postulated that apoptosis contributed to the destabilization of the cell and facilitated viral progeny release.
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Affiliation(s)
- Luiza Deszcz
- Max F. Perutz Laboratories, University Departments at the Vienna Biocenter, Department of Medical Biochemistry, Medical University of Vienna, Dr Bohr Gasse 9/3, A-1030 Vienna, Austria
| | - Elisabeth Gaudernak
- Max F. Perutz Laboratories, University Departments at the Vienna Biocenter, Department of Medical Biochemistry, Medical University of Vienna, Dr Bohr Gasse 9/3, A-1030 Vienna, Austria
| | - Ernst Kuechler
- Max F. Perutz Laboratories, University Departments at the Vienna Biocenter, Department of Medical Biochemistry, Medical University of Vienna, Dr Bohr Gasse 9/3, A-1030 Vienna, Austria
| | - Joachim Seipelt
- Max F. Perutz Laboratories, University Departments at the Vienna Biocenter, Department of Medical Biochemistry, Medical University of Vienna, Dr Bohr Gasse 9/3, A-1030 Vienna, Austria
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61
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Rothen-Rutishauser BM, Kiama SG, Gehr P. A Three-Dimensional Cellular Model of the Human Respiratory Tract to Study the Interaction with Particles. Am J Respir Cell Mol Biol 2005; 32:281-9. [PMID: 15640437 DOI: 10.1165/rcmb.2004-0187oc] [Citation(s) in RCA: 236] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
A novel triple co-culture model of the human airway barrier was designed to simulate the cellular part of the air-blood barrier of the respiratory tract represented by macrophages, epithelial cells, and dendritic cells. When epithelial cells (A549 cells) were grown on filter inserts with pores of 3.0 mum in diameter in a two-chamber system, they formed monolayers with polarization into apical and basolateral domains. The epithelial cell cultures were then supplemented with human blood monocyte-derived macrophages and dendritic cells on the apical and basal aspect, respectively. The single-cell cultures as well as the triple co-cultures were characterized in terms of a number of typical features, for example, morphology of cell types, integrity of epithelial layer, and expression of specific cell surface markers (CD14 for macrophages and CD86 for dendritic cells). The interplay of epithelial cells with macrophages and dendritic cells during the uptake of polystyrene particles (1 mum in diameter) was investigated with confocal laser scanning and conventional transmission electron microscopy. Particles were found in all three cell types, although dendritic cells were not directly exposed to the particles. More investigations are needed to understand the translocation pathway.
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62
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Carterson AJ, Höner zu Bentrup K, Ott CM, Clarke MS, Pierson DL, Vanderburg CR, Buchanan KL, Nickerson CA, Schurr MJ. A549 lung epithelial cells grown as three-dimensional aggregates: alternative tissue culture model for Pseudomonas aeruginosa pathogenesis. Infect Immun 2005; 73:1129-40. [PMID: 15664956 PMCID: PMC547019 DOI: 10.1128/iai.73.2.1129-1140.2005] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A three-dimensional (3-D) lung aggregate model was developed from A549 human lung epithelial cells by using a rotating-wall vessel bioreactor to study the interactions between Pseudomonas aeruginosa and lung epithelial cells. The suitability of the 3-D aggregates as an infection model was examined by immunohistochemistry, adherence and invasion assays, scanning electron microscopy, and cytokine and mucoglycoprotein production. Immunohistochemical characterization of the 3-D A549 aggregates showed increased expression of epithelial cell-specific markers and decreased expression of cancer-specific markers compared to their monolayer counterparts. Immunohistochemistry of junctional markers on A549 3-D cells revealed that these cells formed tight junctions and polarity, in contrast to the cells grown as monolayers. Additionally, the 3-D aggregates stained positively for the production of mucoglycoprotein while the monolayers showed no indication of staining. Moreover, mucin-specific antibodies to MUC1 and MUC5A bound with greater affinity to 3-D aggregates than to the monolayers. P. aeruginosa attached to and penetrated A549 monolayers significantly more than the same cells grown as 3-D aggregates. Scanning electron microscopy of A549 cells grown as monolayers and 3-D aggregates infected with P. aeruginosa showed that monolayers detached from the surface of the culture plate postinfection, in contrast to the 3-D aggregates, which remained attached to the microcarrier beads. In response to infection, proinflammatory cytokine levels were elevated for the 3-D A549 aggregates compared to monolayer controls. These findings suggest that A549 lung cells grown as 3-D aggregates may represent a more physiologically relevant model to examine the interactions between P. aeruginosa and the lung epithelium during infection.
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Affiliation(s)
- A J Carterson
- Department of Microbiology and Immunology, Program in Molecular Pathogenesis and Immunity, Tulane University Health Sciences Center, 1430 Tulane Avenue, New Orleans, LA 70112, USA
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63
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Hermanns MI, Unger RE, Kehe K, Peters K, Kirkpatrick CJ. Lung epithelial cell lines in coculture with human pulmonary microvascular endothelial cells: development of an alveolo-capillary barrier in vitro. J Transl Med 2004; 84:736-52. [PMID: 15077120 DOI: 10.1038/labinvest.3700081] [Citation(s) in RCA: 215] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
We have established a coculture system of human distal lung epithelial cells and human microvascular endothelial cells in order to study the cellular interactions of epithelium and endothelium at the alveolocapillary barrier in both pathogenesis and recovery from acute lung injury. The aim was to determine conditions for the development of functional cellular junctions and the formation of a tight epithelial barrier similar to that observed in vivo. The in vitro coculture system consisted of monolayers of human lung epithelial cell lines (A549 or NCI H441) and primary human pulmonary microvascular endothelial cells (HPMEC) on opposite sides of a permeable filter membrane. A549 failed to show sufficient differentiation with respect to formation of a tight epithelial barrier with intact cell-cell junctions. Stimulated with dexamethasone, the cocultures of NCI H441 and HPMEC established contact-inhibited differentiated monolayers, with NCI H441 showing a continuous, circumferential immunostaining of the tight junctional protein, ZO-1 and the adherens junction protein, E-cadherin. The generation of a polarized epithelial cell monolayer with typical junctional structures was confirmed by transmission electron microscopy. Dexamethasone treatment resulted in average transbilayer electrical resistance (TER) values of 500 Omega cm(2) after 10-12 days of cocultivation and correlated with a reduced flux of the hydrophilic permeability marker, sodium-fluorescein. In addition, basolateral distribution of the proinflammatory cytokine tumour necrosis factor-alpha caused a significant reduction of TER-values after 24 h exposure. This decrease in TER could be re-established to control level by removal of the cytokine within 24 h. Thus, the coculture system of the NCI H441 with HPMEC should be a suitable in vitro model system to examine epithelial and endothelial interactions in the pathogenesis of acute lung injury, infectious lung diseases and toxic lung injury. In addition, it could be used to improve techniques of lung drug delivery that also requires a functional barrier.
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64
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Kauffman HF. Interaction of environmental allergens with airway epithelium as a key component of asthma. Curr Allergy Asthma Rep 2003; 3:101-8. [PMID: 12562548 DOI: 10.1007/s11882-003-0021-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Epithelial cells in the airway wall actively interact with environmental antigens/allergens, both in healthy individuals and patients with asthma. In patients with (allergic) asthma, the epithelium is abnormal, showing damaged structures and continuous activation similar to a repair phenotype cell. Epithelial cells bind allergens by a diversity of innate receptors, similar and in part identical to the Toll-like receptor family, which can induce the release of cytokines, chemokines, and growth factors. Protease-containing extracts (house dust mite, fungi) may additionally cause damage of the epithelial cell layer, thereby enhancing the repair phenotype of epithelial cells in patients with asthma. These interactions may result in facilitation of transport of allergens and enhanced presentation to the immune system (Th2-type response). The inflammatory response induces a second phase of Th2-type cytokines and cytotoxic products that will enhance growth factor-mediated airway remodeling, as is found in asthma. An understanding of the largely unknown innate responses of epithelial cells with environmental antigens/allergens may open new treatment modalities for asthma and other airway diseases.
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Affiliation(s)
- Henk F Kauffman
- Department of Allergology, Clinic for Internal Medicine, University Hospital Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands.
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65
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Florea BI, Cassara ML, Junginger HE, Borchard G. Drug transport and metabolism characteristics of the human airway epithelial cell line Calu-3. J Control Release 2003; 87:131-8. [PMID: 12618029 DOI: 10.1016/s0168-3659(02)00356-5] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pulmonary drug delivery serves two purposes, namely the application of locally active compounds for treatment of diseases afflicting the lung, and the utilization of the pulmonary epithelia as absorption sites for macromolecular drugs. To elucidate the mechanisms involved in the pulmonary absorption and metabolism of compounds on a cellular level, cell culture models have shown to be, though limited, rather useful in predicting in vivo conditions. The Calu-3 cell line has been employed recently as a model for the airway epithelium in a number of drug transport and metabolism studies. The results of these studies, as well as an evaluation of the predictive potency of the model, are presented here.
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Affiliation(s)
- Bogdan I Florea
- Leiden/Amsterdam Center for Drug Research, Division of Pharmaceutical Technology, PO Box 9502, 2300 RA Leiden, The Netherlands
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Baker SF, Yin Y, Runswick SK, Stewart GA, Thompson PJ, Garrod DR, Robinson C. Peptidase allergen Der p 1 initiates apoptosis of epithelial cells independently of tight junction proteolysis. Mol Membr Biol 2003; 20:71-81. [PMID: 12745920 DOI: 10.1080/0968768021000061150] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Loss of epithelial cell polarity, which can arise following disruption of tight junctions (TJs), is a precursor to the care-fully orchestrated removal of moribund cells from epithelia in apoptosis. Ordinarily, this cycle of events has minimally disruptive effects on the function of the epithelial barrier, but some agents have been identified that induce apoptosis and promote epithelial leakiness. The allergen Der p 1 is a cysteine peptidase that cleaves TJ adhesion proteins and induces apoptosis in epithelial cells. This suggests the possibility that, at least for some inducers of apoptosis, these events might be causally linked. We report here that Der p 1 induces epithelial apoptosis before outright cell detachment and that apoptosis occurs within the same time span as increased paracellular permeability in polarized epithelial monolayers. Whilst TJ-deficient BEAS-2B cells were resistant to Der p 1-induced apoptosis, the cell line 1HAEo-, which was also TJ deficient, was sensitive to Der p 1, providing evidence against TJ proteolysis as a cause of apoptosis. To provide direct evidence, we propagated cells that normally express TJs in low calcium medium that prevented intercellular junction assembly. These cells retained full susceptibility to Der p 1, indicating that Der p 1-induced apoptosis is independent from TJ proteolysis.
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Affiliation(s)
- Sharon F Baker
- Department of Pharmacology & Clinical Pharmacology, St George's Hospital Medical School, London, UK
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67
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Patel J, Pal D, Vangal V, Gandhi M, Mitra AL. Transport of HIV-protease inhibitors across 1 alpha,25di-hydroxy vitamin D3-treated Calu-3 cell monolayers: modulation of P-glycoprotein activity. Pharm Res 2002; 19:1696-703. [PMID: 12458676 DOI: 10.1023/a:1020761514471] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE The presence of P-glycoprotein (P-gp) within the lipid bi-layers of the absorptive cells greatly influences drug entry into the HIV-infected sanctuary sites. The objective of this study was to acces the potential role of pulmonary cells expressing high levels of P-gp in the efflux of potent anti-HIV drugs such as protease inhibitors. METHODS Human airway epithelium-derived Calu-3 cells grown in the presence of 0.025 mM 1alpha,25di-hydroxy Vitamin D3 (di-OH vit D3) were used as a model to evaluate the effects of p-glycoprotein efflux of HIV protease inhibitors. Cells used as controls were not treated with di-OH vit D3. The anti-HIV agents 3H Ritonavir and Saquinavir (50 microM) were used as model compounds for influx and efflux studies RESULTS Di-OH vit D3 treatment enhanced the differentiation c Calu-3 cells indicated by more cilia and mucus secretion. It also caused elevated P-gp expression as demonstrated by Western Bla analysis and enhanced basal to apical transport of cyclosporine as compared with untreated cells. The amount of Saquinavir transported, after 3 h, across untreated Calu-3 cells (A-B) was 3-fold higher (1.62 microg; Papp = 2A (+/- 0.79) x 10(-6) cm/s) than di-OH vi D3-treated cells (0.57 microg with the Papp = 5.02 (+/- 0.62) x 10(-7) cm/s) Similar transport profiles were obtained for 3H ritonavir and a significant increase (p < 0.05) in the A-B transport (2.5-fold) of 3H ritonavir was observed when the cell monolayers were preincubated with testosterone prior to transport studies. However, transport of AZT remained unaltered in di-OH vit D3 treated monolayers. CONCLUSION Modulation of P-gp activity may be necessary to increase the therapeutic efficacy of protease inhibitors against HIV-1 reservoirs across alveolar lining cells and fluids.
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Affiliation(s)
- Jignesh Patel
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri, 5005 Rockhill Road, Kansas City, Misouri 64110-2499, USA
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Jumarie C. Cadmium transport through type II alveolar cell monolayers: contribution of transcellular and paracellular pathways in the rat ATII and the human A549 cells. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1564:487-99. [PMID: 12175933 DOI: 10.1016/s0005-2736(02)00499-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Cadmium (CD) transport in alveolar type II (ATII) cells has been studied using two in vitro models widely used to investigate lung function: primary cultures of rat ATII cells and the human cell line A549. Nonlinear regression analyses of the uptake time-course of (109)Cd revealed: a zero-time accumulation, a fast process of accumulation which proceeds within minutes, and a much slower process which takes hours. This three-step mechanism was characterized by different parameter values under dishes-or filter-growth conditions. A higher initial uptake rate (v(i)) and equilibrium accumulation (A(max)) of (109)Cd were found in the rat ATII cells; these differences were not related to a higher level of adsorption onto the external surface of the cell membrane. Specific transport systems of similar capacity but different affinity (threefold higher in rat cells) were characterized. A significant transepithelial transport of (109)Cd, with similar P(coeff) in both cell models, could not be exclusively related to cellular metal release. Results on 3H-mannitol permeability together with (109)Cd efflux data strongly suggest a greater contribution of the paracellular pathways in Cd transport through A549 cell monolayers. These differences in transport properties between the two lung cell models may modify the dose-response curve for Cd toxicity.
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Affiliation(s)
- C Jumarie
- Département des Sciences Biologiques, Toxen, Université du Québec à Montréal, C.P. 8888, Succ. centre-ville, Montréal, Québec, Canada H3C 3P8.
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Florea BI, Meaney C, Junginger HE, Borchard G. Transfection efficiency and toxicity of polyethylenimine in differentiated Calu-3 and nondifferentiated COS-1 cell cultures. AAPS PHARMSCI 2002; 4:E12. [PMID: 12423061 PMCID: PMC2751351 DOI: 10.1208/ps040312] [Citation(s) in RCA: 151] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In the present study, we evaluated polyethylenimine (PEI) of different molecular weights (MWs) as a DNA complexing agent for its efficiency in transfecting nondifferentiated COS-1 (green monkey fibroblasts) and well-differentiated human submucosal airway epithelial cells (Calu-3). Studying the effect of particle size, zeta potential, presence of serum proteins or chloroquine, it appeared that transfection efficiency depends on the experimental conditions and not on the MW of the PEI used. Comparing transfection efficiencies in both cell lines, we found that PEI was 3 orders of magnitude more effective in COS-1 than in Calu-3 cells, because Calu-3 cells are differentiated and secrete mucins, which impose an additional barrier to gene delivery. Transfection efficiency was strongly correlated to PEI cytotoxicity. Also, some evidence for PEI-induced apoptosis in both cell lines was found. In conclusion, our results indicate that PEI is a useful vector for nonviral transfection in undifferentiated cell lines. However, results from studies in differentiated bronchial epithelial cells suggest that PEI has yet to be optimized for successful gene therapy of cystic fibrosis (CF).
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Affiliation(s)
- Bogdan I. Florea
- Division of Pharmaceutical Technology, Leiden/Amsterdam Center for Drug Research, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Clare Meaney
- Division of Pharmaceutical Technology, Leiden/Amsterdam Center for Drug Research, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Hans E. Junginger
- Division of Pharmaceutical Technology, Leiden/Amsterdam Center for Drug Research, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Gerrit Borchard
- Division of Pharmaceutical Technology, Leiden/Amsterdam Center for Drug Research, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
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Pezron I, Mitra R, Pal D, Mitra AK. Insulin aggregation and asymmetric transport across human bronchial epithelial cell monolayers (Calu-3). J Pharm Sci 2002; 91:1135-46. [PMID: 11948552 DOI: 10.1002/jps.10114] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The purpose of this work was to elucidate the transport pathways of zinc insulin across the Calu-3 cell monolayer, an in vitro model of the human airway epithelium. Calu-3 cells grown in liquid-covered conditions formed a confluent monolayer with a high transepithelial electrical resistance value of 1000 +/- 150 Omega small middle dot cm(2). The cell monolayer was characterized by a low mannitol permeability of 4.7 +/- 0.5 10(-7)cm/s. Transport of zinc insulin (donor concentration 1 U/mL) in Dulbecco's modified phosphate buffer saline at 37 degrees C was found to be higher in the basolateral (BL) to apical (AP) (P(app) = 3.0 +/- 0.2 10(-8) cm/s), than in the AP to BL direction (P(app) = 0.41 +/- 0.02 10(-8) cm/s). P-glycoprotein efflux or specific enzymatic degradation did not appear to contribute toward this asymmetric transport. Insulin receptors, though apparently more abundant on the BL side than on the AP side of Calu-3 cells, did not mediate the direction-dependent transport of insulin. However, transport of a monomeric human insulin analog, Asp(B10)des(B28-30), across the Calu-3 cell monolayer was similar in both directions (BL to AP and AP to BL). The corresponding permeability, P(app) = 2.9 +/- 0.2 10(-8) cm/s, was not significantly different from the permeability of zinc insulin in the BL to AP direction. The paracellular pathway seems to play a major role in the insulin transport across the Calu-3 cell monolayers. We hypothesize that the transport of zinc insulin oligomers is restricted at the AP surface by the presence of the tight junctional complexes. From the BL side, oligomers may undergo dissociation in the intercellular space and diffuse readily as monomers to the AP surface of the membrane.
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Affiliation(s)
- Isabelle Pezron
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri, 5005 Rockhill Road, Kansas City, Missouri 64110-2499, USA
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71
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Florea BI, van der Sandt ICJ, Schrier SM, Kooiman K, Deryckere K, de Boer AG, Junginger HE, Borchard G. Evidence of P-glycoprotein mediated apical to basolateral transport of flunisolide in human broncho-tracheal epithelial cells (Calu-3). Br J Pharmacol 2001; 134:1555-63. [PMID: 11724763 PMCID: PMC1573081 DOI: 10.1038/sj.bjp.0704390] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. Transepithelial transport of flunisolide was studied in reconstituted cell monolayers of Calu-3, LLC-PK1 and the MDR1-P-glycoprotein transfected LLC-MDR1 cells. 2. Flunisolide transport was polarized in the apical (ap) to basolateral (bl) direction in Calu-3 cells and was demonstrated to be ATP-dependent. In LLC-MDR1 cells, flunisolide was transported in the bl to ap direction and showed no polarization in LLC-PK1 cells. 3. Non-specific inhibition of cellular metabolism at low temperature (4 degrees C) or by 2-deoxy-D-glucose (2-d-glu) and sodium azide (NaN(3)) abolished the polarized transport. Polarized flunisolide transport was also inhibited by the specific Pgp inhibitors verapamil, SDZ PSC 833 and LY335979. 4. Under all experimental conditions and in the presence of all used inhibitors, no decrease in the TransEpithelial Electrical Resistance (TEER) values was detected. From all inhibitors used, only the general metabolism inhibitors 2-deoxy-D-glucose and NaN(3), decreased the survival of Calu-3 cells. 5. Western blotting analysis and confocal laser scanning microscopy demonstrated the presence of MDR1-Pgp at mainly the basolateral side of the plasma membrane in Calu-3 cells and at the apical side in LLC-MDR1 cells. Mass spectroscopy studies demonstrated that flunisolide is transported unmetabolized across Calu-3 cells. 6. In conclusion, these results show that the active ap to bl transport of flunisolide across Calu-3 cells is facilitated by MDR1-Pgp located in the basolateral plasma membrane.
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Affiliation(s)
- Bogdan I Florea
- Division of Pharmaceutical Technology, Leiden/Amsterdam Center for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands
| | | | - S Mariette Schrier
- Division of Toxicology, LACDR, Leiden University, 2300 RA Leiden, The Netherlands
| | - Klazina Kooiman
- Division of Pharmaceutical Technology, Leiden/Amsterdam Center for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands
| | - Koen Deryckere
- Division of Pharmaceutical Technology, Leiden/Amsterdam Center for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands
| | - Albertus G de Boer
- Division of Pharmacology, LACDR, Leiden University, 2300 RA Leiden, The Netherlands
| | - Hans E Junginger
- Division of Pharmaceutical Technology, Leiden/Amsterdam Center for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands
| | - Gerrit Borchard
- Division of Pharmaceutical Technology, Leiden/Amsterdam Center for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands
- Author for correspondence:
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72
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Sanjar S, Matthews J. Treating systemic diseases via the lung. JOURNAL OF AEROSOL MEDICINE : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY FOR AEROSOLS IN MEDICINE 2001; 14 Suppl 1:S51-8. [PMID: 11424894 DOI: 10.1089/08942680150506349] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Inhalation of pharmacologically active substances for medicinal, social, or recreational purposes has been prevalent for centuries but experience of exploiting the lung as a route of delivery for treatment of nonrespiratory diseases is limited. Despite the success of current applications such as anesthetics, the utility of the lung for drug delivery is not well appreciated, despite advantages such as rapid onset of action. Two drawbacks are the relatively poor efficiency of current inhalation devices, especially for large molecules, and the poor patient acceptability of inhalers. Advances now being made in pulmonary delivery technology may provide the impetus needed for the development of new inhaled presentations of drugs such as peptide hormones and other biologically derived molecules. Molecules of various sizes can be delivered in clinically relevant quantities via the lung. In vitro methods show that lipophilic drugs are absorbed through the alveolar membrane more quickly. Early work in animal models has already shown that absorption of analgesic and antiinflammatory drugs that are not well absorbed orally can be improved by delivering them by inhalation. This work may soon give rise to new formulations for therapeutic use.
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Affiliation(s)
- S Sanjar
- Glaxo Wellcome, Research Triangle Park, North Carolina 27709, USA.
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73
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Lacherade JC, Van De Louw A, Planus E, Escudier E, D'Ortho MP, Lafuma C, Harf A, Delclaux C. Evaluation of basement membrane degradation during TNF-alpha-induced increase in epithelial permeability. Am J Physiol Lung Cell Mol Physiol 2001; 281:L134-43. [PMID: 11404256 DOI: 10.1152/ajplung.2001.281.1.l134] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We evaluated whether tumor necrosis factor (TNF)-alpha induces an increase in permeability of an alveolar epithelial monolayer via gelatinase secretion and basement membrane degradation. Gelatinase secretion and epithelial permeability to radiolabeled albumin under unstimulated and TNF-alpha-stimulated conditions of an A549 human epithelial cell line were evaluated in vitro. TNF-alpha induced both upregulation of a 92-kDa gelatinolytic activity (pro form in cell supernatant and activated form in extracellular matrix) and an increase in the epithelial permeability coefficient compared with the unstimulated condition (control: 1.34 +/- 0.04 x 10(-6) cm/s; 1 microg/ml TNF-alpha: 1.47 +/- 0.05 x 10(-6) cm/s, P < 0.05). The permeability increase in the TNF-alpha-stimulated condition involved both paracellular permeability, with gap formation visualized by actin cytoskeleton staining, and basement membrane permeability, with an increase in the basement membrane permeability coefficient (determined after cell removal; control: 2.58 +/- 0.07 x 10(-6) cm/s; 1 microg/ml TNF-alpha: 2.82 +/- 0.02.10(-6) x cm/s, P < 0.05). Because addition of gelatinase inhibitors [tissue inhibitor of metalloproteinase (TIMP)-1 or BB-3103] to cell supernatants failed to inhibit the permeability increase, the gelatinase-inhibitor balance in the cellular microenvironment was further evaluated by cell culture on a radiolabeled collagen matrix. In the unstimulated condition, spontaneous collagenolytic activity inhibited by addition to the matrix of 1 microg/ml TIMP-1 or 10(-6) M BB-3103 was found. TNF-alpha failed to increase this collagenolytic activity because it was associated with dose-dependent upregulation of TIMP-1 secretion by alveolar epithelial cells. In conclusion, induction by TNF-alpha of upregulation of both the 92-kDa gelatinase and its inhibitor TIMP-1 results in maintenance of the gelatinase-inhibitor balance, indicating that basement membrane degradation does not mediate the TNF-alpha-induced increase in alveolar epithelial monolayer permeability.
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Affiliation(s)
- J C Lacherade
- Institut National de la Santé et de la Recherche Médicale Unité 492 and Service de Physiologie, Explorations Fonctionnelles (Assistance Publique-Hôpitaux de Paris), Hôpital Henri Mondor, 94010 Créteil, France
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Abstract
The purpose of this work was to determine if the sub-bronchial epithelial cell model, Calu-3, expresses the functionally active P-glycoprotein (Pgp) efflux pump. Calu-3 cells express lower levels of Pgp than both Caco-2 and A549 cells as determined by Western Blot analysis. In Calu-3 cells, accumulation of the Pgp substrates rhodamine 123 (Rh123) and calcein acetoxymethyl ester (calcein-AM) was increased in the presence of the specific Pgp inhibitors cyclosporin A (CsA), vinblastine, and taxol. Significant inhibition of Pgp activity was not observed until after 2 h in both cell lines. The organic anion/multidrug resistance associated protein-1 (MRP1) inhibitors, probenecid and indomethacin, did not affect Rh123 accumulation, whereas an increase in calcein accumulation was observed by both agents. The metabolic inhibitor sodium azide decreased the efflux of Rh123 out of Calu-3 cells to the same degree as CsA, supporting inhibition of an active, efflux pathway. The basolateral-to-apical transport of Rh123 was significantly higher than that in the reverse direction, indicating a secretory pathway of efflux that was inhibited 25-fold by CsA. Basolateral-to-apical transport of Rh123 was inhibited slightly with both MRP1 inhibitors; however, no significant effect of Rh123 net secretion was observed. Mixed inhibitor studies demonstrated that Rh123 efflux was mainly Pgp mediated. These results support an energy-dependent Pgp efflux pump pathway that is sensitive to inhibition with CsA in Calu-3 cells.
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Affiliation(s)
- K O Hamilton
- Department of Pharmaceutical Chemistry, 236B Simons Laboratories, 2095 Constant Avenue, The University of Kansas, Lawrence, Kansas 66047, USA
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75
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Wan H, Winton HL, Soeller C, Taylor GW, Gruenert DC, Thompson PJ, Cannell MB, Stewart GA, Garrod DR, Robinson C. The transmembrane protein occludin of epithelial tight junctions is a functional target for serine peptidases from faecal pellets of Dermatophagoides pteronyssinus. Clin Exp Allergy 2001; 31:279-94. [PMID: 11251630 DOI: 10.1046/j.1365-2222.2001.00970.x] [Citation(s) in RCA: 193] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
There have been only a few studies of how allergens cross the airway epithelium to cause allergic sensitization. House dust mite fecal pellets (HDMFP) contain several proteolytic enzymes. Group 1 allergens are cysteine peptidases, whilst those of groups 3, 6 and 9 have catalytic sites indicative of enzymes that mechanistically behave as serine peptidases. We have previously shown that the group 1 allergen Der p 1 leads to cleavage of tight junctions (TJs), allowing allergen delivery to antigen presenting cells. In this study we determined whether HDMFP serine peptidases similarly compromise the airway epithelium by attacking TJs, desmosomes and adherens junctions. Experiments were performed in monolayers of MDCK, Calu-3 or 16HBE14o-epithelial cells. Cell junction morphology was examined by 2-photon molecular excitation microscopy and digital image analysis. Barrier function was measured as mannitol permeability. Cleavage of cell adhesion proteins was studied by immunoblotting and mass spectrometry. HDMFP serine peptidases led to a progressive cleavage of TJs and increased epithelial permeability. Desmosomal puncta became more concentrated. Cleavage of TJs involved proteolysis of the TJ proteins, occludin and ZO-1. This was associated with activation of intracellular proteolysis of ZO-1. In contrast to occludin, E-cadherin of adherens junctions was cleaved less extensively. Although Calu-3 and 16HBE14o-cells expressed tethered ligand receptors for serine peptidases, these were not responsible for transducing the changes in TJs. HDMFP serine peptidases cause cleavage of TJs. This study identifies a second general class of HDM peptidase capable of increasing epithelial permeability and thereby creating conditions that would favour transepithelial delivery of allergens.
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Affiliation(s)
- H Wan
- Department of Pharmacology & Clinical Pharmacology, St George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, UK
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Foster KA, Avery ML, Yazdanian M, Audus KL. Characterization of the Calu-3 cell line as a tool to screen pulmonary drug delivery. Int J Pharm 2000; 208:1-11. [PMID: 11064206 DOI: 10.1016/s0378-5173(00)00452-x] [Citation(s) in RCA: 181] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The objective of this research was to examine the human sub-bronchial gland cell line, Calu-3, and assess its potential as a metabolic and transport model to study drug delivery to the respiratory epithelium. The present studies were conducted using Calu-3 cells grown in Transwells(R) or in multiwell cluster plates. TEER values for Calu-3 monolayers were determined using the World Precision Instrument Voltohmmeter and STX-2 electrode. The results confirmed that Calu-3 cells form tight monolayers and give appreciable TEER values in culture when grown under air-interface conditions. Permeability data for small lipophilic molecules across Calu-3 monolayers suggested that the cell line is a suitable model to examine the transport of low molecular weight substances and xenobiotics. Calu-3 cells were also found to efflux FITC-transferrin (MW 80000) in a polarized manner. The metabolic capacity of Calu-3 cells was also examined. The P4501A1 and P4502B isozymes were determined to be functional, but not inducible, with fluorescent resorufin assays. The data indicated that the Calu-3 cell line may be useful for studying the contributions of bronchial epithelial cells to mechanisms of drug delivery at the respiratory epithelium.
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Affiliation(s)
- K A Foster
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS 66047, USA
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77
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Ring PC, Wan H, Schou C, Kroll Kristensen A, Roepstorff P, Robinson C. The 18-kDa form of cat allergen Felis domesticus 1 (Fel d 1) is associated with gelatin- and fibronectin-degrading activity. Clin Exp Allergy 2000; 30:1085-96. [PMID: 10931115 DOI: 10.1046/j.1365-2222.2000.00805.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Fel d 1, an important allergen from domestic cats, is a significant cause of asthma. In addition to directly promoting IgE synthesis, other biological activities of allergens may contribute to either allergic sensitization or the magnitude of allergic effector responses. For example, allergens that degrade proteins have been suggested to facilitate allergen presentation by increasing parallelular permeability of airways epithelium. However, little information exists to indicate whether Fel d 1 has other activities relevant to allergic responses. OBJECTIVE To study whether Fel d 1 is associated with enzyme activity. METHODS Fel d 1 was obtained by a rigorous purification strategy and its identity confirmed by laser desorption mass spectrometry, cleavage and sequencing. The ability of Fel d 1 to degrade gelatin, fibronectin and the artificial substrate N-benzoyl-FVR-p-nitroanilide was studied. The effect of Fel d 1 on the morphology of tight junctions in epithelial cell monolayers was also investigated. RESULTS The 18-kDa form of Fel d 1 caused degradation of denatured collagens (gelatin) and cleaved a 20-kDa fragment from the A chain of plasma fibronectin. Catalytic activity was not altered by inhibitors of cysteine peptidases, matrix metallopeptidases or by removal of divalent cations. In contrast, aprotinin and TLCK were inhibitors of Fel d 1. The absence of a serine peptidase catalytic triad in Fel d 1, together with the stoichiometry of the inhibition of TLCK and aprotinin, suggest that their inhibitory action may be due to noncatalytic site interactions. Alternatively, highly purified Fel d 1 may be associated with an active contaminant, although none were found. CONCLUSION These results suggest that Fel d 1 is another example of a domestic allergen which is associated with enzyme activity. It remains to be established whether the activity resides in Fel d 1 itself or in an unresolved, and possibly related, protein.
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Affiliation(s)
- P C Ring
- Department of Pharmacology and Clinical Pharmacology, St George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, United Kingdom
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78
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Wan H, Winton HL, Soeller C, Gruenert DC, Thompson PJ, Cannell MB, Stewart GA, Garrod DR, Robinson C. Quantitative structural and biochemical analyses of tight junction dynamics following exposure of epithelial cells to house dust mite allergen Der p 1. Clin Exp Allergy 2000; 30:685-98. [PMID: 10792361 DOI: 10.1046/j.1365-2222.2000.00820.x] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND House dust mite allergen Der p 1 is a cysteine peptidase. Previously, we have suggested that the proteolytic activity of this allergen may contribute to asthma by damaging the barrier formed by the airways epithelium. OBJECTIVE The present study applied novel techniques to compare changes in permeability with quantitative events in tight junctions (TJs) and desmosomes (DMs) of epithelial cells exposed to Der p 1. METHODS Confluent monolayers of Madin-Darby canine kidney (MDCK) and 16HBE14o-human bronchial epithelial cells were used as experimental models. Permeability was estimated from mannitol clearance. Digital imaging with quantification of TJs and DMs was achieved by fluorescent antibody staining and 2-photon molecular excitation microscopy (2PMEM). Biochemical changes in TJs were studied by immunoblotting, radiolabelling and immunoprecipitation. RESULTS Der p 1 caused a time-dependent breakage of TJs and reduction in their content of the protein ZO-1. Reduction in ZO-1 immunofluorescence at TJs occurred with a small increase in the amount of diffuse, cytoplasmic immunoreactive ZO-1 staining. Morpho-logical changes in TJs occurred in synchrony with increases in epithelial permeability. DM puncta increased both in size and intensity of staining. Immunoblotting demonstrated that the disruption of TJ morphology was associated with cleavage of ZO-1 and occludin. Cells recovered from allergen exposure by de novo synthesis of occludin. CONCLUSION Der p 1 could contribute to sensitization and allergic responses by degrading the function of the airway epithelial barrier.
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Affiliation(s)
- H Wan
- Department of Pharmacology & Clinical Pharmacology, St George's Hospital Medical School, London, UK
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79
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Human airway epithelial cell lines for in vitro drug transport and metabolism studies. PHARMACEUTICAL SCIENCE & TECHNOLOGY TODAY 2000; 3:18-27. [PMID: 10637597 DOI: 10.1016/s1461-5347(99)00231-x] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The pharmaceutical industry relies on appropriate in vitro models for the evaluation of drug absorption and metabolism. Despite increasing interest in drug delivery via the lung, there is currently no widely accepted cell culture model of the airway epithelium. This review considers the airway epithelium, the culture of airway epithelial cells and the need for cell lines which can model the airway epithelium. Three of the most promising human bronchial cell lines, 16HBE14o-, Calu-3 and BEAS-2B, are reviewed, with emphasis on their recent application for the study of drug transport, drug metabolism and gene delivery. Current limitations and future directions for the development of these cell lines as models of the airway epithelium are discussed.
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80
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Wan H, Winton HL, Soeller C, Tovey ER, Gruenert DC, Thompson PJ, Stewart GA, Taylor GW, Garrod DR, Cannell MB, Robinson C. Der p 1 facilitates transepithelial allergen delivery by disruption of tight junctions. J Clin Invest 1999; 104:123-33. [PMID: 10393706 PMCID: PMC408401 DOI: 10.1172/jci5844] [Citation(s) in RCA: 548] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
House dust mite (HDM) allergens are important factors in the increasing prevalence of asthma. The lung epithelium forms a barrier that allergens must cross before they can cause sensitization. However, the mechanisms involved are unknown. Here we show that the cysteine proteinase allergen Der p 1 from fecal pellets of the HDM Dermatophagoides pteronyssinus causes disruption of intercellular tight junctions (TJs), which are the principal components of the epithelial paracellular permeability barrier. In confluent airway epithelial cells, Der p 1 led to cleavage of the TJ adhesion protein occludin. Cleavage was attenuated by antipain, but not by inhibitors of serine, aspartic, or matrix metalloproteinases. Putative Der p 1 cleavage sites were found in peptides from an extracellular domain of occludin and in the TJ adhesion protein claudin-1. TJ breakdown nonspecifically increased epithelial permeability, allowing Der p 1 to cross the epithelial barrier. Thus, transepithelial movement of Der p 1 to dendritic antigen-presenting cells via the paracellular pathway may be promoted by the allergen's own proteolytic activity. These results suggest that opening of TJs by environmental proteinases may be the initial step in the development of asthma to a variety of allergens.
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Affiliation(s)
- H Wan
- Department of Pharmacology and Clinical Pharmacology, St. George's Hospital Medical School, London SW17 0RE, United Kingdom
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Carver JE, Galloway WA, Robinson C. Inhibition of gelatinase activity in human airway epithelial cells and fibroblasts by dexamethasone and beclomethasone. Br J Pharmacol 1999; 127:1119-28. [PMID: 10455257 PMCID: PMC1566123 DOI: 10.1038/sj.bjp.0702650] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The effects of dexamethasone and beclomethasone on gelatinase activity released from lung epithelial cells (A549, NCI-H292 and Calu-3 cell lines and NHBE primary cultures) and human lung fibroblasts (HLF) were investigated. All cells spontaneously released gelatin-degrading activity but the amounts were unaffected by treatment with glucocorticoids. Phorbol myristate acetate (PMA) increased the amount of gelatinase activity in conditioned media prepared from all cell types examined. In epithelial cells, PMA induced the expression of gelatinase B, whereas in HLF the increased gelatinase activity resulted from increased activation of gelatinase A. Dexamethasone and beclomethasone produced concentration-dependent inhibition of PMA-induced gelatinase activity in HLF and epithelial cell lines. In the epithelial cell lines, the inhibition of activity was associated with an attenuation of enzyme induction by PMA. In contrast, primary cultures of human bronchial epithelial cells were unresponsive to dexamethasone at concentrations that were maximally effective at inhibiting gelatinase activity induced in other cells.
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Affiliation(s)
- Julia E Carver
- Department of Pharmacology & Clinical Pharmacology, St George's Hospital Medical School, Cranmer Terrace, London SW17 0RE
| | - W Alan Galloway
- British Biotech Pharmaceuticals Limited, Watlington Road, Cowley OX4 5LY
| | - Clive Robinson
- Department of Pharmacology & Clinical Pharmacology, St George's Hospital Medical School, Cranmer Terrace, London SW17 0RE
- Author for correspondence:
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