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Background and objectiveWe assessed whether co-deposition of a long-acting (2)-agonist and a corticosteroid affects their respective transport rates across epithelial cells. MethodsDrug particles were deposited on the air-interface culture of Calu-3 cells using a twin-stage impinger. We compared the transport rate of salmeterol and fluticasone across the epithelial cells using commercially available formulations (Serevent, Flixotide and Seretide). The transepithelial resistance of Calu-3 cells was measured before and after each deposition to monitor epithelial resistance. ResultsThe codeposition of salmeterol and fluticasone had no significant effect on transport of salmeterol through the cell layer. In contrast, the rate of fluticasone propionate transport in presence of salmeterol xinofoate was significantly lower (0.530.20%) compared with the single fluticasone formulation (2.360.97%). Furthermore, the resistance of the epithelial cells was significantly increased after salmeterol deposition from both single and combination products. ConclusionsOur data demonstrate that salmeterol may decrease the permeability of epithelial cells, resulting in slower fluticasone transport across Calu-3 epithelial monolayers. The subsequent increased residence time of fluticasone in the airways could prolong its anti-inflammatory effects.

Submitted by arlindo kohlrausch (ajfk@uepg.br) on 2022-04-13T16:44:17Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Josyel Olszewski.pdf: 2368298 bytes, checksum: 3e0bf650859904bfcaead57f143d127c (MD5) Made available in DSpace on 2022-04-13T16:44:17Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Josyel Olszewski.pdf: 2368298 bytes, checksum: 3e0bf650859904bfcaead57f143d127c (MD5) Previous issue date: 2016-07-18 Bactérias fixadoras de nitrogênio estão sendo cada vez mais utilizadas como fertilizantes biológicos (biofertilizantes) em substituição aos fertilizantes químicos. O gênero Herbaspirillum foi inicialmente isolado de gramíneas de interesse agrícola no Brasil e devido a sua capacidade de fixar nitrogênio atmosférico, tem sido testada como biofertilizante de algumas culturas como a cana de açúcar e o milho. Porém, mesmo sendo considerado um gênero não-patogênico, seus mecanismos de interação com as plantas são semelhantes aos mecanismos de infecção de uma bactéria patogênica e, recentemente, foram relatados casos de isolamento dessa bactéria em pacientes hospitalizados, geralmente imunocomprometidos e/ou com doenças graves como leucemia e principalmente fibrose cística. Considerando isso, o objetivo do presente estudo foi o de avaliar o potencial patogênico das seguintes cepas do gênero Herbaspirilum: cepa ambiental H. seropedicae SmR1 e suas formas modificadas (RAM GFP e ds RED) e as cepas de isolados clínicos H. frisingense AU14559 e H. huttiense AU11883. Testes in vitro utilizando os reagentes MTT e VN foram realizados para avaliar a viabilidade de células pulmonares Calu-3 após exposição ao sobrenadante estéril das culturas bacterianas com 8 ou 18 h de crescimento, evidenciando a citotoxicidade das diferentes cepas da espécie H. seropedicae. Ensaios de morfologia celular utilizando os mesmos sobrenadantes induziram alterações morfológicas nas células Calu-3 com todas as cepa testadas. A metodologia de adesão mostrou que as cepas isoladas de infecções em humanos, H. huttiense AU11883 e H. frisingense AU14559, são capazes de aderir sobre as células Calu-3, sendo consideradas bactérias de baixa adesão. Nos ensaios in vivo, utilizando um modelo de indução de pneumonia em camundongos, a cepa H. seropedicae SmR1 foi capaz de induzir perda severa de peso desses animais, aumento na contagem total de leucócitos e proporção de neutrófilos no lavado broncoalveolar (LBA), além de alterações histopatológicas nos pulmões, como infiltrado perivascular e peribronquiolar. A cepa isolada de infecções pulmonares, H. huttiense AU11883, apresentou citotoxicidade e adesão in vitro, além de alterações histológicas no pulmão dos animais inoculados intratraquealmente, mas não houve perda de peso ou alterações significativas no LBA. Esses resultados demonstram que a cepa ambiental H. seropedicae SmR1 apresentou indícios que confirmam seu potencial patogênico, mas ainda são necessários testes com um número maior de cepas para avaliar o potencial patogênico deste gênero bacteriano. Nitrogen fixing bacteria are being widely used as biological fertilizers (biofertilizers) as a substitute to chemical compounds. Herbaspirillum genus was first isolated from grasses of agricultural interest in Brazil and, due to their ability to fix atmospheric nitrogen, has been tested as a biofertilizer in some agricultural crops such as sugar cane and corn. However, even being considered a non-pathogenic genus, their interaction mechanism with plants are similar to mechanism of infections from a pathogenic bacterium and recently there have been reports of isolation of these bacteria in hospitalized patients, usually in immunocompromised patients and/or with severe diseases like leukemia and mainly cystic fibrosis. Regarding this, the objective of this study was to evaluate the pathogenic potential of the strains of the genus Herbaspirillum: environmental strain H. seropedicae SmR1 and their modified forms (RAM GFP and ds RED) and the clinical isolated strains H. frisingense AU14559 e H. huttiense AU11883. In vitro tests using reagents MTT and Neutral Red were performed to evaluate lung cells Calu-3 viability following exposure to sterile supernatant of bacterial cultures with 8 and 18 h of growth, showing cytotoxic effect of all different strains of the species H. seropedicae used. Morphology cell tests using the same supernatants induced alterations in Calu-3 cells with all bacterium strains used. Cell adhesion methodology showed that the human isolated strains H. huttiense AU11883 and H. frisingense AU14559 are capable of adhering on Calu-3 cells, being considered low adhesion bacteria. In in vivo assays, using a pneumonia induced model in mice, H. seropedicae SmR1 strain was able to induce severe weight loss in those animals, as well as a rise in total leukocytes count and neutrophils on bronchoalveolar lavage (LBA) and histopathological changes on the lungs, like perivascular and peribronchial infiltrates. The clinical isolated strain from infected lungs, H. huttiense AU11883, showed cytotoxicity and adhesion in vitro, and also histopathological changes on the lungs of intratracheal inoculated animals, but they didn’t show weight loss or significant alterations on LBA. Those results shows that the environmental strain H. seropedicae SmR1 presented evidence confirming its pathogenic potential, but are still required further tests with a larger number of strains to evaluate the pathogenic potential of this bacterial genus.

Purpose The first step in developing a new inhalable formulation for the treatment of respiratory diseases is to understand the mechanisms involved in the absorption of drugs after lung deposition. This information could be important for the treatment of bacterial infection in the lung, where low permeability would probably be beneficial, or a systemic infection, where high permeability would be desirable. The goal of this study was to evaluate the transport of several antibiotics (ciprofloxacin, azithromycin, moxifloxacin, rifampicin, doxycycline and tobramycin) across human bronchial airway epithelium and to study the influence of molecular weight and LogP on the apparent permeability. Methods The experiments were conducted using Calu-3 cells seeded in the apical compartment of 24-well Transwell® inserts. The antibiotics transport was measured in both apical to basolateral (A–B) and basolateral to apical (B–A) directions and the apparent permeability of each antibiotic was calculated. Results The A–B transport of ciprofloxacin and rifampicin was independent of the initial concentration in the donor compartment, suggesting the involvement of active transporters in their absorption. Moxifloxacin, doxycycline, azithromycin and tobramycin presented a low absorptive permeation in the A–B direction, indicating that these substances could be substrate for efflux pumps. Generally, all antibiotics studied showed low permeabilities in the B–A direction. Conclusions These findings suggest that the inhalation route would be favorable for delivering these specific antibiotics for the treatment of respiratory infection, compared with present oral or intravenous administration.

Respiratory syncytial virus (RSV) replication is primarily limited to the upper respiratory tract epithelium and primary, differentiated normal human bronchial epithelial cells (NHBE) have, therefore, been considered a good system for in vitro analysis of lung tissue response to respiratory virus infection and virus-host interactions. However, NHBE cells are expensive, difficult to culture, and vary with the source patient. An alternate approach is to use a continuous cell line that has features of bronchial epithelial cells such as Calu-3, an epithelial cell line derived from human lung adenocarcinoma, as an in vitro model of respiratory virus infection. The results show that Calu-3 fully polarize when grown on permeable supports as liquid-covered cultures. Polarized Calu-3 are susceptible to RSV infection and release infectious virus primarily from the apical surface, consistent with studies in NHBE cells. The data demonstrate that polarized Calu-3 may serve as a useful in vitro model to study host responses to RSV infection.

International audience; Lung administration of antibiotics by nebulization is promising for improving treatment efficiency for pulmonary infections, as it increases drug concentration at sites of infection while minimizing systemic side effects. For poorly soluble molecules like rifampicin, cyclodextrins (CD) may improve lung delivery by permitting higher dosing. For this purpose, we investigated rifampicin-CD complexes in terms of rifampicin apparent solubility enhancement, effect on in vitro permeability on Calu-3 broncho-alveolar cells, effect on in vitro antibacterial activity against Acinetobacter baumannii and nebulization characteristics measured by NGI cascade impactor. Complexation efficiency between rifampicin and methylated beta-cyclodextrin (RAMEB) or hydroxypropyl-beta-cyclodextrin (HPbetaCD) was pH-dependent, involving the piperazin group. Rifampicin phase solubility diagrams constructed at pH 9 showed an A(L)-type curve for RAMEB and a B(S)-type for HPbetaCD. Stability constants calculated for a 1:1 molar ratio of CD/rifampicin were 73.4 +/- 8.2 M(-1) for RAMEB and 68.5 +/- 5.2 M(-1) for HPbetaCD. Complexes with RAMEB or HPbetaCD increased 22 times and 7.6 times respectively the apparent solubility of rifampicin and were found to be satisfactorily stable for 2 days when diluted in a solution at physiological pH. The nebulization of the complex solution created droplets in size range compatible with pulmonary deposition. Furthermore, the presence of HPbetaCD decreased the MMAD of the aerosolized droplets. Activity of RAMEB and HPbetaCD complexes measured by the total rifampicin MIC against A. baumannii was similar or lower to free rifampicin MIC respectively. Complexation did not alter the rifampicin permeability in the timescale of 1h as evaluated with a Calu-3 epithelial cell model, but acted as a reservoir for rifampicin. In conclusion, this work reports that CDs can be used as vectors for pulmonary nebulization to increase the amount of active rifampicin and optimize its lung pharmacokinetic profile.

© 2015 Elsevier B.V. Abstract The aim of the study was to prepare inhalable resveratrol by spray drying for the treatment of chronic obstructive pulmonary disease (COPD). Resveratrol, with a spherical morphology and particle diameter less than 5 μm, was successfully manufactured. Fine particle fraction (FPF) and mass median aerodynamic diameter (MMAD) of spray-dried resveratrol was 39.9 ± 1.1% and 3.7 ± 0.1 μm, respectively, when assessed with an Andersen cascade impactor (ACI) at 60 l/min. The cytotoxicity results of resveratrol on Calu-3 revealed that the cells could tolerate high concentration of resveratrol (up to 160 μM). In addition, in transport experiments using Snapwells, it was observed that more than 80% of the deposited dry powder was transported across the Calu-3 cells to the basal chamber within four hours. The expression of interleukin-8 (IL-8) from Calu-3 induced with tumor necrosis factor alpha (TNF-α), transforming growth factor beta (TGF-β1) and lipopolysaccharide (LPS) were significantly reduced after treatment with spray-dried resveratrol. The antioxidant assay (radical scavenging activity and nitric oxide production) showed spray-dried resveratrol to possess an equivalent antioxidant property as compared to vitamin C. Results presented in this investigation suggested that resveratrol could potentially be developed as a dry powder for inhalation for the treatment of inflammatory lung diseases like COPD.

The study focuses on the application of a cell integrated modified Andersen Cascade Impactor (ACI) as an in vitro lung model for the evaluation of aerosols’ behaviour of different formulation devices, containing the same active drug, specifically nebuliser, pressurised metered dose inhaler (pMDI) and dry powder inhaler (DPI). Deposition and transport profiles of the three different inhaled salbutamol sulphate (SS) formulations with clinically relevant doses were evaluated using a modified ACI coupled with the air interface Calu-3 bronchial cell model. Reproducible amounts of SS were deposited on Snapwells for the different formulations, with no significant difference in SS deposition found between the standard ACI plate and modified plate. The transport of SS aerosols produced from pMDI formulation had similar transport kinetics to nebulised SS but significantly higher compared to the DPI, which could have led to the differences in clinical outcomes. Furthermore, drug absorption of different inhaled formulation devices of the same aerodynamic fraction was found not to be equivalent due to their physical chemical properties upon aerosolisation. This study has established an in vitro platform for the evaluation of the different inhaled formulations in physiologically relevant pulmonary conditions.

The purpose of this study was to determine the effect of PEGylation on the interaction of poly(amidoamine) (PAMAM) dendrimer nanocarriers (DNCs) with in vitro and in vivo models of the pulmonary epithelium. Generation-3 PAMAM dendrimers with varying surface densities of PEG 1000 Da were synthesized and characterized. The results revealed that the apical to basolateral transport of DNCs across polarized Calu-3 monolayers increases with an increase in PEG surface density. DNC having the greatest number of PEG groups (n = 25) on their surface traversed at a rate 10-fold greater than its non-PEGylated counterpart, in spite of their larger size. This behavior was attributed to a significant reduction in charge density upon PEGylation. We also observed that PEGylation can be used to modulate cellular internalization. The total uptake of PEG-free DNC into polarized Calu-3 monolayers was 12% (w/w) vs 2% (w/w) for that with 25 PEGs. Polarization is also shown to be of great relevance in studying this in vitro model of the lung epithelium. The rate of absorption of DNCs administered to mice lungs increased dramatically when conjugated with 25 PEG groups, thus supporting the in vitro results. The exposure obtained for the DNC with 25PEG was determined to be very high, with peak plasma concentrations reaching 5 μg·mL(-1) within 3 h. The combined in vitro and in vivo results shown here demonstrate that PEGylation can be potentially used to modulate the internalization and transport of DNCs across the pulmonary epithelium. Modified dendrimers thereby may serve as a valuable platform that can be tailored to target the lung tissue for treating local diseases, or the circulation, using the lung as pathway to the bloodstream, for systemic delivery.

The aim of this study was to assess the effects of low-dose clarithromycin, formulated as solution pressurized metered dose inhaler, following deposition on the Calu-3 respiratory epithelial cells.Clarithromycin was deposited on the air-interface culture of Calu-3 cells using a modified Andersen cascade impactor. Transport of fluorescein-Na, production of mucus and interleukin-8 release from Calu-3 cells following stimulation with transforming growth factor-β and treatment with clarithromycin was investigated.The deposition of clarithromycin had significant effect on the permeability of fluorescein-Na, suggesting that the barrier integrity was improved following a short-term treatment with clarithromycin (apparent permeability values were reduced to 3.57 × 10(-9) ± 2.32 × 10(-9) cm.s(-1), compared to 1.14 × 10(-8) ± 4.30 × 10(-8) cm.s(-1) for control). Furthermore, the amount of mucus produced was significantly reduced during the course of clarithromycin treatment. The concentration of interleukin-8 secreted from Calu-3 cells following stimulation with transforming growth factor-β resulted in significantly lower level of interleukin-8 released from the cells pre-treated with clarithromycin (5.2 ± 0.5 ng.ml(-1) clarithromycin treated vs. 7.7 ± 0.8 ng.ml(-1) control, respectively).Our data demonstrate that treatment with clarithromycin decreases the paracellular permeability of epithelial cells, mucus secretion and interleukin-8 release and therefore, inhaled clarithromycin holds potential as an anti-inflammatory therapy.

We investigated the role of Toll-like receptor (TLR) 2 in maintaining the integrity of the airway epithelial barrier using the human bronchial epithelial cell line Calu-3. Activation of TLR2 by its ligands, Pam3CysSK4 and Peptidoglycan showed a concentration dependent increase in epithelial barrier function, as measured by transepithelial electrical resistance (TEER). This was confirmed by a decrease in paracellular flux of fluorescein sodium. This TLR2 induced increase in TEER was significantly reduced by pretreatment with polyclonal anti-human TLR2-neutralizing antibody. TLR2 stimulation in Calu-3 cell monolayers resulted in an increased expression of the tight junction proteins claudin-1 and ZO-1, and a decreased expression of occludin, at both the mRNA and protein levels. A pseudosubstrate inhibitor to PKCζ significantly prevented the TLR2 mediated increase in barrier function. It also prevented the increase in claudin-1 in a concentration dependent manner up to 1 µM. TLR2 stimulation led to an increase in phosphorylation of atypical PKC ζ, which was prevented by the pseudosubstrate inhibitor in a concentration dependent manner. Taken together, our observations support a model whereby increased tight junction barrier function induced by activation of TLR2 occurs through increased expression of claudin-1, and through modulation of PKC ζ activity.

BACKGROUND: Hypothermia with xenon gas has been used to reduce brain injury and disability rate after perinatal hypoxia-ischemia. We evaluated xenon gas therapy effects in an in vitro model with or without hypothermia on cultured human airway epithelial cells (Calu-3). METHODS: Calu-3 monolayers were grown at an air-liquid interface and exposed to one of the following conditions: 1) 21% FiO2 at 37°C (control); 2) 45% FiO2 and 50% xenon at 37°C; 3) 21% FiO2 and 50% xenon at 32°C; 4) 45% FiO2 and 50% xenon at 32°C for 24 hours. Transepithelial resistance (TER) measurements were performed and apical surface fluids were collected and assayed for total protein, IL-6, and IL-8. Three monolayers were used for immunofluorescence localization of zonula occludens-1 (ZO-1). The data were analyzed by one-way ANOVA. RESULTS: TER decreased at 24 hours in all treatment groups. Xenon with hyperoxia and hypothermia resulted in greatest decrease in TER compared with other groups. Immunofluorescence localization of ZO-1 (XY) showed reduced density of ZO-1 rings and incomplete ring-like staining in the 45% FiO2– 50% xenon group at 32°C compared with other groups. Secretion of total protein was not different among groups. Secretion of IL-6 in 21% FiO2 with xenon group at 32°C was less than that of the control group. The secretion of IL-8 in 45% FiO2 with xenon at 32°C was greater than that of other groups. CONCLUSION: Hyperoxia and hypothermia result in detrimental epithelial cell function and inflammation over 24-hour exposure. Xenon gas did not affect cell function or reduce inflammation.

This work explored the interaction of chitosan with Calu-3 and Caco-2 cell lines, as models of the airway and intestinal epithelium, respectively. The toxicity, tight junction opening and mucoadhesive effects of chitosan were compared in the two cell lines. Additionally, the role of mucus in the absorption-promoting activity of chitosan was studied systematically. Notably, chitosan exhibited a different degree of toxicity on the Calu-3 and Caco-2 cells. Chitosan's tight junction-opening effect, observed in terms of reduction of transepithelial electrical resistance and permeability enhancement, was apparent in both cell lines, though somewhat lower in Caco-2 compared to Calu-3 cell layers (though overall permeability was higher in the former). Tight junction opening and association of chitosan with the epithelial cell layers were more prominent in mucus-containing than in mucus-depleted Calu-3 cells and non mucus-excreting Caco-2 monolayers. Overall, the work suggests that chitosan exhibits a different level of toxicity in airway, as compared to intestinal cells and although absorption enhancement is apparent in both cell lines, enabling its potential use as an absorption-promoting excipient in both pulmonary and oral macromolecular delivery, the magnitude and the duration of the effect are dependent on the level of mucus present on the epithelial surfaces.

Chitosan is a biocompatible polysaccharide of natural origin and has been the subject of interest for its use as a polymeric drug carrier materials in mucosal vaccination. Derivates of this biopolymer are regarded as being usable due to their biocompatibility, biodegradability, and absence of toxicity. As derivatives, trimethylated chitosan (TMC) and 6-O-carboxymethyl-N,N,N-trimethylchitosan (CM-TMC) polymers demonstrated beneficial water-solubility at physiological pH value. They also feature adjuvant properties by acting as permeation enhancers, transiently opening intercellular tight junctions. Thereby these polymers enable paracellular transport of drugs, which can be useful for the formulation of mucosal vaccines. Calu-3 cell monolayers are a valuable model for predicting paracellular transport kinetics in airway epithelia. Accordingly, the polymers will be tested in Calu-3 cells to study the contribution of these derivates on drug delivery at the respiratory epithelium.

Destruction of the architectural and subsequently the functional integrity of the lung following pulmonary viral infections is attributable to both the extent of pathogen replication and to the host-generated inflammation associated with the recruitment of immune responses. The presence of antigenically disparate pulmonary viruses and the emergence of novel viruses assures the recurrence of lung damage with infection and resolution of each primary viral infection. Thus, there is a need to develop safe broad spectrum immunoprophylactic strategies capable of enhancing protective immune responses in the lung but which limits immune-mediated lung damage. The immunoprophylactic strategy described here utilizes a protein cage nanoparticle (PCN) to significantly accelerate clearance of diverse respiratory viruses after primary infection and also results in a host immune response that causes less lung damage.

Present work investigates the potential of chitosan nanoparticles, formulated by the ionic gelation with tripolyphosphate (TPP), to open the cellular tight junctions and in doing so, improve the permeability of model macromolecules. A comparison is made with chitosan solution at equivalent concentrations. Initial work assessed cytotoxicity (through MTS and LDH assays) of chitosan nanoparticles and solutions on Calu-3 cells. Subsequently, a concentration of chitosan nanoparticles and solution exhibiting minimal toxicity was used to investigate the effect on TEER and macromolecular permeability across filter-cultured Calu-3 monolayer. Chitosan nanoparticles and solution were also tested for their effect on the distribution of the tight junction protein, zonnula occludens-1 (ZO-1). Chitosan nanoparticles produced a sharp and reversible decrease in TEER and increased the permeability of two FITC-dextrans (FDs), FD4 (MW 4 kDa) and FD10 (MW 10 kDa), with effects of a similar magnitude to chitosan solution. Chitosan nanoparticles produced changes in ZO-1 distribution similar to chitosan solution, indicating a tight junction effect. While there was no improvement in permeability with chitosan nanoparticles compared to solution, nanoparticles provide the potential for drug incorporation, and hence the possibility for providing controlled drug release and protection from enzymatic degradation.

Simona Mura1,2, Herve Hillaireau1,2, Julien Nicolas1,2, Benjamin Le Droumaguet1,2, Claire Gueutin1,2, Sandrine Zanna3, Nicolas Tsapis1,2, Elias Fattal1,2 1Univ Paris-Sud, UMR 8612, Châtenay Malabry, F-92296; 2CNRS, Châtenay Malabry, F-92296; 3Laboratoire de Physico-Chimie des Surfaces, CNRS-ENSCP (UMR 7045), Ecole Nationale Superiore de Chimie de Paris, France Background: Because of the described hazards related to inhalation of manufactured nanoparticles, we investigated the lung toxicity of biodegradable poly (lactide-co-glycolide) (PLGA) nanoparticles displaying various surface properties on human bronchial Calu-3 cells. Methods: Positively and negatively charged as well as neutral nanoparticles were tailored by coating their surface with chitosan, Poloxamer, or poly (vinyl alcohol), respectively. Nanoparticles were characterized in terms of size, zeta potential, and surface chemical composition, confirming modifications provided by hydrophilic polymers. Results: Although nanoparticle internalization by lung cells was clearly demonstrated, the cytotoxicity of the nanoparticles was very limited, with an absence of inflammatory response, regardless of the surface properties of the PLGA nanoparticles. Conclusion: These in vitro results highlight the safety of biodegradable PLGA nanoparticles in the bronchial epithelium and provide initial data on their potential effects and the risks associated with their use as nanomedicines. Keywords: nanoparticles, PLGA, surface properties, Calu-3, toxicity, inflammation

The impact of P-glycoprotein (MDR1, ABCB1) on drug disposition in the lungs as well as its presence and activity in in vitro respiratory drug absorption models remain controversial to date. Hence, we characterised MDR1 expression and the bidirectional transport of the common MDR1 probe (3)H-digoxin in air-liquid interfaced (ALI) layers of normal human bronchial epithelial (NHBE) cells and of the Calu-3 bronchial epithelial cell line at different passage numbers. Madin-Darby Canine Kidney (MDCKII) cells transfected with the human MDR1 were used as positive controls. (3)H-digoxin efflux ratio (ER) was low and highly variable in NHBE layers. In contrast, ER=11.4 or 3.0 were measured in Calu-3 layers at a low or high passage number, respectively. These were, however, in contradiction with increased MDR1 protein levels observed upon passaging. Furthermore, ATP depletion and the two MDR1 inhibitory antibodies MRK16 and UIC2 had no or only a marginal impact on (3)H-digoxin net secretory transport in the cell line. Our data do not support an exclusive role of MDR1 in (3)H-digoxin apparent efflux in ALI Calu-3 layers and suggest the participation of an ATP-independent carrier. Identification of this transporter might provide a better understanding of drug distribution in the lungs.

Background Respiratory syncytial virus (RSV) is a major cause of severe lower respiratory tract illness in young children worldwide. Treatment options for severe RSV disease remain limited and the development of therapeutic treatment strategies remains a priority. LL-37, a small cationic host defense peptide involved in anti-inflammatory and anti-bacterial responses, reduces replication of or infection by multiple viruses, including influenza virus, in vitro, and protects against lethal challenge with influenza virus in vivo. LL-37 also protects against RSV infection of HEp-2 cells in vitro; however, HEp-2 are not reflective of polarized airway epithelial cells and respond differently to RSV infection. An air–liquid interface (ALI) Calu-3 model that more closely mimics the human airway epithelium was established. Using this in vitro model, the effectiveness of LL-37 in preventing RSV infection and replication was examined. Results LL-37, when pre-incubated with virus prior to RSV infection (prophylactic), significantly reduced the level of viral genome detected in infected Calu-3 cells, and decreased chemokine expression associated with RSV infection in vitro. In contrast, therapeutic treatment of RSV-infected ALI Calu-3 at 24 h and 3 days post-infection had minimal impact on RSV infection. Conclusions Differences in the efficacy of LL-37 at reducing RSV infection under prophylactic and therapeutic conditions may in part be ascribed to differences in the method of peptide exposure. However, the efficacy of LL-37 at reducing RSV infection under prophylactic conditions indicates that further studies examining the efficacy of LL-37 as a small peptide inhibitor of RSV are warranted.

Allicin (diallyl thiosulfinate) is the major thiol-reactive organosulfur compound produced by garlic plants (Allium sativum) upon tissue damage. Allicin exerts its strong antimicrobial activity against bacteria and fungi via S-thioallylation of protein thiols and low molecular weight thiols. Here, we investigated the effect of allicin on SARS-CoV-2 infected Vero E6 and Calu-3 cells. Toxicity tests revealed that Calu-3 cells showed greater allicin tolerance, probably due to >4-fold higher GSH levels compared to the very sensitive Vero E6 cells. Exposure of infected Vero E6 and Calu-3 cells to biocompatible allicin doses led to a ���60���70% decrease of viral RNA and infectious viral particles. Label-free quantitative proteomics was used to investigate the changes in the Calu-3 proteome after SARS-CoV-2 infection and the effect of allicin on the host-virus proteome. SARS-CoV-2 infection of Calu-3 cells caused a strong induction of the antiviral interferon-stimulated gene (ISG) signature, including several antiviral effectors, such as cGAS, Mx1, IFIT, IFIH, IFI16, IFI44, OAS, and ISG15, pathways of vesicular transport, tight junctions (KIF5A/B/C, OSBPL2, CLTCL1, and ARHGAP17) and ubiquitin modification (UBE2L3/5), as well as reprogramming of host metabolism, transcription and translation. Allicin treatment of infected Calu-3 cells reduced the expression of IFN signaling pathways and ISG effectors and reverted several host pathways to levels of uninfected cells. Allicin further reduced the abundance of the structural viral proteins N, M, S and ORF3 in the host-virus proteome. In conclusion, our data demonstrate the antiviral and immunomodulatory activity of biocompatible doses of allicin in SARS-CoV-2-infected cell cultures. Future drug research should be directed to exploit the thiol-reactivity of allicin derivatives with increased stability and lower human cell toxicity as antiviral lead compounds.

Allicin (diallyl thiosulfinate) is the major thiol-reactive organosulfur compound produced by garlic plants (Allium sativum) upon tissue damage. Allicin exerts its strong antimicrobial activity against bacteria and fungi via S-thioallylation of protein thiols and low molecular weight thiols. Here, we investigated the effect of allicin on SARS-CoV-2 infected Vero E6 and Calu-3 cells. Toxicity tests revealed that Calu-3 cells showed greater allicin tolerance, probably due to >4-fold higher GSH levels compared to the very sensitive Vero E6 cells. Exposure of infected Vero E6 and Calu-3 cells to biocompatible allicin doses led to a ���60���70% decrease of viral RNA and infectious viral particles. Label-free quantitative proteomics was used to investigate the changes in the Calu-3 proteome after SARS-CoV-2 infection and the effect of allicin on the host-virus proteome. SARS-CoV-2 infection of Calu-3 cells caused a strong induction of the antiviral interferon-stimulated gene (ISG) signature, including several antiviral effectors, such as cGAS, Mx1, IFIT, IFIH, IFI16, IFI44, OAS, and ISG15, pathways of vesicular transport, tight junctions (KIF5A/B/C, OSBPL2, CLTCL1, and ARHGAP17) and ubiquitin modification (UBE2L3/5), as well as reprogramming of host metabolism, transcription and translation. Allicin treatment of infected Calu-3 cells reduced the expression of IFN signaling pathways and ISG effectors and reverted several host pathways to levels of uninfected cells. Allicin further reduced the abundance of the structural viral proteins N, M, S and ORF3 in the host-virus proteome. In conclusion, our data demonstrate the antiviral and immunomodulatory activity of biocompatible doses of allicin in SARS-CoV-2-infected cell cultures. Future drug research should be directed to exploit the thiol-reactivity of allicin derivatives with increased stability and lower human cell toxicity as antiviral lead compounds.

Purpose: To evaluate the ability of human airway epithelial cell layers and a simple rat isolated perfused lung (IPL) model to predict pulmonary drug absorption in rats in vivo. Method: The permeability of seven compounds selected to possess a range of lipophilicity was measured in two airway cell lines (Calu-3 and 16HBE14o-), in normal human bronchial epithelial (NHBE) cells and using a simple isolated perfused lungs (IPL) technique. Data from the cell layers and ex vivo lungs were compared to published absorption rates from rat lungs measured in vivo. Results: A strong relationship was observed between the logarithm of the in vivo absorption half-life and the absorption half-life in the IPL (r = 0.97; excluding formoterol). Good log-linear relationships were also found between the apparent first-order absorption rate in vivo and cell layer permeability with correlation coefficients of 0.92, 0.93, 0.91 in Calu-3, 16HBE14o- and NHBE cells, respectively. Conclusion: The simple IPL technique provided a good prediction of drug absorption from the lungs, making it a useful method for empirical screening of drug absorption in the lungs. Permeability measurements were similar in all the respiratory epithelial cell models evaluated, with Calu-3 having the advantage for routine permeability screening purposes of being readily availability, robust and easy to culture.