Human Lung Epithelial A549 Cells Research Articles

The South Pacific epidemic strain of Zika virus replicates efficiently in human epithelial A549 cells leading to IFN-β production and apoptosis induction

Zika virus (ZIKV) is an emerging flavivirus since the first epidemics in South Pacific in 2007. The recent finding that ZIKV is now circulating in Western Hemisphere and can be associated to severe human diseases, warrants the need for its study. Here we evaluate the susceptibility of human lung epithelial A549 cells to South Pacific epidemic strain of ZIKV isolated in 2013. We showed that ZIKV growth in A549 cells is greatly efficient. ZIKV infection resulted in the secretion of IFN-β followed by the expression of pro-inflammatory cytokines such as IL-1β, and transcriptional activity of IFIT genes. At the maximum of virus progeny production, ZIKV triggers mitochondrial apoptosis through activation of caspases-3 and -9. Whereas at early infection times, the rapid release of IFN-β which exerts an antiviral effect against ZIKV might delay apoptosis in infected cells.

Water soluble and insoluble components of urban PM2.5 and their cytotoxic effects on epithelial cells (A549) in vitro

When PM2.5 enters human bodies, the water soluble (WS-PM2.5) and insoluble components (WIS-PM2.5) of PM2.5 would interact with cells and cause adverse effects. However, the knowledge about the individual toxicity contribution of these two components is limited. In this study, the physiochemical properties of PM2.5 were well characterized. The toxic effects of WS-PM2.5 and WIS-PM2.5, which include the cell viability, cell membrane damage, reactive oxygen species (ROS) generation and morphological changes, were examined with human lung epithelial A549 cells in vitro. The results indicated that WS-PM2.5 could induce the early response of ROS generation, multiplied mitochondria and multi-lamellar bodies in A549 cells, which might cause cell damage through oxidative stress. Meanwhile, WIS-PM2.5 was predominantly associated with the cell membrane disruption, which might lead to the cell damage through cell-particle interactions. Moreover, the synergistic cytotoxic effects of WS-PM2.5 and WIS-PM2.5 were observed at longer exposure time. These findings demonstrate the different cytotoxicity mechanisms of WS-PM2.5 and WIS-PM2.5, which suggest that not only the size and dosage of PM2.5 but also the solubility of PM2.5 should be taken into consideration when evaluating the toxicity of PM2.5.

Reconstitution of ST2 (IL-1R4) specific for IL-33 activity; no suppression by IL-1Ra though a common chain IL-1R3 (IL-1RAcP) shared with IL-1

Interleukin-33 (IL-33) receptors are composed of ST2 (also known as IL-1R4), a ligand binding chain, and IL-1 receptor accessory protein (IL-1RAcP, also known as IL-1R3), a signal transducing chain. IL-1R3 is a common receptor for IL-1α, and IL-1β, IL-33, and three IL-36 isoforms. A549 human lung epithelial cells are highly sensitive to IL-1α and IL-1β but not respond to IL-33. The lack of responsiveness to IL-33 is due to ST2 expression. ST2 was stably transfected into A549 cells to reconstitute its activity. RT-PCR and FACS analysis confirmed ST2 expression on the cell surface of A549/ST2 cells. Upon IL-33 stimulation, A549/ST2 cells induced IL-8 and IL-6 production in a dose dependent manner while A549/mock cells remained unresponsive. There was no difference in IL-1α and IL-1β activity in A549/ST2 cells compared to A549/mock cells despite the fact that IL-33 shares IL-1R3 with IL-1α/β. IL-33 activated inflammatory signaling molecules in a time- and dose-dependent manner. Anti-ST2 antibody and soluble recombinant ST2-Fc abolished IL-33-induced IL-6 and IL-8 production in A549/ST2 cells but the IL-1 receptor antagonist failed to block IL-33-induced cytokines. This result demonstrates for the first time the reconstitution of ST2 in A549 human lung epithelial cell line and verified its function in IL-33-mediated cytokine production and signal transduction.

Genetic characterization of an adapted pandemic 2009 H1N1 influenza virus that reveals improved replication rates in human lung epithelial cells

The 2009 influenza pandemic originated from a swine-origin H1N1 virus, which, although less pathogenic than anticipated, may acquire additional virulence-associated mutations in the future. To estimate the potential risk, we sequentially passaged the isolate A/Hamburg/04/2009 in A549 human lung epithelial cells. After passage 6, we observed a 100-fold increased replication rate. High-throughput sequencing of viral gene segments identified five dominant mutations, whose contribution to the enhanced growth was analyzed by reverse genetics. The increased replication rate was pinpointed to two mutations within the hemagglutinin (HA) gene segment (HA1 D130E, HA2 I91L), near the receptor binding site and the stem domain. The adapted virus also replicated more efficiently in mice in vivo. Enhanced replication rate correlated with increased fusion pH of the HA protein and a decrease in receptor affinity. Our data might be relevant for surveillance of pre-pandemic strains and development of high titer cell culture strains for vaccine production.

Reverse Genetics for Fusogenic Bat-Borne Orthoreovirus Associated with Acute Respiratory Tract Infections in Humans: Role of Outer Capsid Protein σC in Viral Replication and Pathogenesis.

Nelson Bay orthoreoviruses (NBVs) are members of the fusogenic orthoreoviruses and possess 10-segmented double-stranded RNA genomes. NBV was first isolated from a fruit bat in Australia more than 40 years ago, but it was not associated with any disease. However, several NBV strains have been recently identified as causative agents for respiratory tract infections in humans. Isolation of these pathogenic bat reoviruses from patients suggests that NBVs have evolved to propagate in humans in the form of zoonosis. To date, no strategy has been developed to rescue infectious viruses from cloned cDNA for any member of the fusogenic orthoreoviruses. In this study, we report the development of a plasmid-based reverse genetics system free of helper viruses and independent of any selection for NBV isolated from humans with acute respiratory infection. cDNAs corresponding to each of the 10 full-length RNA gene segments of NBV were cotransfected into culture cells expressing T7 RNA polymerase, and viable NBV was isolated using a plaque assay. The growth kinetics and cell-to-cell fusion activity of recombinant strains, rescued using the reverse genetics system, were indistinguishable from those of native strains. We used the reverse genetics system to generate viruses deficient in the cell attachment protein σC to define the biological function of this protein in the viral life cycle. Our results with σC-deficient viruses demonstrated that σC is dispensable for cell attachment in several cell lines, including murine fibroblast L929 cells but not in human lung epithelial A549 cells, and plays a critical role in viral pathogenesis. We also used the system to rescue a virus that expresses a yellow fluorescent protein. The reverse genetics system developed in this study can be applied to study the propagation and pathogenesis of pathogenic NBVs and in the generation of recombinant NBVs for future vaccines and therapeutics.

Methyl syringate, a TRPA1 agonist represses hypoxia-induced cyclooxygenase-2 in lung cancer cells

BackgroundWe have previously found that methyl syringate is a specific and selective agonist of the human transient receptor potential channel ankyrin 1 (TRPA1) and suppresses food intake and gastric emptying in imprinting control region mice. Because TRPA1 has been implicated in inflammatory responses, and inflammation and tumorigenesis are stimulated by the cyclooxygenase-2 (COX-2)/prostaglandin E2 pathway in hypoxic cancer cells. PurposeThis study examined the effects of methyl syringate on hypoxia-induced COX-2 in human distal lung epithelial A549 cells. Study designThe effect of the methyl syringate on suppression of hypoxia-induced COX-2 in A549 cells were determined by Western blot and/or quantitative real-time polymerase chain reaction. The anti-invasive effect of methyl syringate was evaluated on A549 cells using matrigel invasion assay. ResultsMethyl syringate suppressed hypoxia-induced COX-2 protein and mRNA expression and promoter activity and reduced hypoxia-induced cell migration and invasion and secretion of vascular endothelial growth factor. These effects were antagonized by a TRPA1 antagonist, implying their mediation by the TRPA1 pathway. ConclusionTogether, these results indicate that methyl syringate inhibits the hypoxic induction of COX-2 expression and cell invasion through TRPA1 activation. These findings suggest that methyl syringate could be effective to suppress hypoxia-induced inflammation and indicate an additional functional effect of methyl syringate.

Double thin film-based sandwich-cell carrier design for multicellular tissue engineering

Many organs are multicellular and each cell type requires a different microenvironment. Thus, there is a need for modular structures where the microenvironment of each cell type can be tuned separately. Herein, we describe enzymatically crosslinked gelatin based double layered film structures where each layer can be loaded with growth factors separately. As a model, we have developed a bi-layer system to produce a respiratory epithelium. This system constitutes an in vitro “epithelial patch” that can be adhered to the lumen of any implant. Crosslinking of the patches with transglutaminase resulted in 7days of stability at 37°C. The film layer was first used to release growth factors and it was shown that the release significantly improved the proliferation over 5days. A549 human lung epithelial cells were used and under the release of an epithelial growth supplement mix, there was a significant improvement on the epithelial proliferation (p<0.01). The designed substrate was successfully attached to titanium implants and we demonstrated the stability of the epithelial patch under in vitro conditions for 7days without deterioration. Under co-culture conditions for three days both cell types were alive. Such patches can be used to obtain fast epithelialization of large implant surfaces.

Chemically synthesized CdSe quantum dots inhibit growth of human lung carcinoma cells via ROS generation.

Quantum dots (QDs), semiconducting materials have potential applications in the field of electronic and biomedical applications including cancer therapy. In present study, cadmium selenide (CdSe) QDs were synthesized by chemical method. Octadecene was used as non-coordinating solvent which facilitated the formation of colloidal solutions of nanoparticles. CdSe QDs were characterized by UV-vis spectrometer and transmission electron microscope (TEM). The size measured by TEM was varied between 2-5 nm depending upon temperature. The cytotoxic activity of QDs was monitored by MTT assay, nuclear condensation, ROS activity and DNA fragmentation assay on human lung epithelial A549 cell line. Cells were treated with different concentrations of varying size of CdSe QDs for 24 h. CdSe QDs induced significant (p < 0.05) dose dependent cytotoxicity and this was comparable to the sizes of particles. Smaller particles were more cytotoxic to the large particles. Fluorescence microscopic analysis revealed that QDs induced oxidative stress generating significant ROS level and consequently, induced nuclear condensation and DNA fragmentation. Study suggested the cytotoxicity of CdSe QDs via ROS generation and DNA fragmentation depending upon particles size.

AdcAII of Streptococcus pneumoniae Affects Pneumococcal Invasiveness.

Across bacterial species, metal binding proteins can serve functions in pathogenesis in addition to regulating metal homeostasis. We have compared and contrasted the activities of zinc (Zn2+)-binding lipoproteins AdcA and AdcAII in the Streptococcus pneumoniae TIGR4 background. Exposure to Zn2+-limiting conditions resulted in delayed growth in a strain lacking AdcAII (ΔAdcAII) when compared to wild type bacteria or a mutant lacking AdcA (ΔAdcA). AdcAII failed to interact with the extracellular matrix protein laminin despite homology to laminin-binding proteins of related streptococci. Deletion of AdcA or AdcAII led to significantly increased invasion of A549 human lung epithelial cells and a trend toward increased invasion in vivo. Loss of AdcAII, but not AdcA, was shown to negatively impact early colonization of the nasopharynx. Our findings suggest that expression of AdcAII affects invasiveness of S. pneumoniae in response to available Zn2+ concentrations.

Matrine Attenuates COX-2 and ICAM-1 Expressions in Human Lung Epithelial Cells and Prevents Acute Lung Injury in LPS-Induced Mice.

Matrine is isolated from Sophora flavescens and shows anti-inflammatory effects in macrophages. Here we evaluated matrine's suppressive effects on cyclooxygenase 2 (COX-2) and intercellular adhesion molecule-1 (ICAM-1) expressions in lipopolysaccharide- (LPS-) stimulated human lung epithelial A549 cells. Additionally, BALB/c mice were given various matrine doses by intraperitoneal injection, and then lung injury was induced via intratracheal instillation of LPS. In LPS-stimulated A549 cells, matrine inhibited the productions of interleukin-8 (IL-8), monocyte chemotactic protein-1, and IL-6 and decreased COX-2 expression. Matrine treatment also decreased ICAM-1 protein expression and suppressed the adhesion of neutrophil-like cells to inflammatory A549 cells. In vitro results demonstrated that matrine significantly inhibited mitogen-activated protein kinase phosphorylation and decreased nuclear transcription factor kappa-B subunit p65 protein translocation into the nucleus. In vivo data indicated that matrine significantly inhibited neutrophil infiltration and suppressed productions of tumor necrosis factor-α and IL-6 in mouse bronchoalveolar lavage fluid and serum. Analysis of lung tissue showed that matrine decreased the gene expression of proinflammatory cytokines, chemokines, COX-2, and ICAM-1. Our findings suggest that matrine improved lung injury in mice and decreased the inflammatory response in human lung epithelial cells.

Identification of cellular microRNA-136 as a dual regulator of RIG-I-mediated innate immunity that antagonizes H5N1 IAV replication in A549 cells.

H5N1 influenza A virus (IAV) causes severe respiratory diseases and high mortality rates in animals and humans. MicroRNAs are being increasingly studied to evaluate their potential as therapeutic entities to combat viral infection. However, mechanistic studies delineating the roles of microRNAs in regulating host-H5N1 virus interactions remain scarce. Here, we performed microRNA microarray analysis using A549 human lung epithelial cells infected with a highly pathogenic avian influenza virus. The microRNA expression profile of infected cells identified a small number of microRNAs being dysregulated upon H5N1 influenza A virus infection. Of the differentially expressed microRNAs, miR-136 was up-regulated 5-fold and exhibited potent antiviral activity in vitro against H5N1 influenza A virus, as well as vesicular stomatitis virus. On the one hand, 3′-untranslated region (UTR) reporter analysis revealed a miR-136 binding site in the 3′ UTR of IL-6. However, on the other hand, we subsequently determined that miR-136 meanwhile acts as an immune agonist of retinoic acid-inducible gene 1 (RIG-I), thereby causing IL-6 and IFN-β accumulation in A549 cells. Overall, this study implicates the dual role of miRNA-136 in the regulation of host antiviral innate immunity and suggests an important role for the microRNA-activated pathway in viral infection via pattern recognition receptors.

Comparative analysis of virulence traits between a Legionella feeleii strain implicated in Pontiac fever and a strain that caused Legionnaires' disease

Legionella strains of the same species and serogroup are known to cause Legionnaires' disease (a potentially fatal atypical pneumonia) or Pontiac fever (a mild, flu-like disease), but the bacterial factors that define these dramatic differences in pathology have not been elucidated. To gain a better understanding of these factors, we compared the characteristics of Legionella feeleii strains that were isolated from either a sample of freshwater implicated in an outbreak of Pontiac fever (ATCC 35072, serogroup 1, LfPF), or a patient with Legionnaires' disease (ATCC 38549, serogroup 2, LfLD). Growth of LfPF and LfLD in BYE broth was slower than the positive control, Legionella pneumophila strain JR32. However, LfLD grew faster than LfPF at 42 °C. After in vitro infection to J774 murine or U937 human macrophage cell lines and A549 human lung epithelial cell line, LfLD showed a higher cell infection rate, stronger internalization by host cells, and greater cytotoxicity than that of LfPF. Large amounts of IL-6 and IL-8 were secreted by human host cells after infection with LfLD, but not with LfPF. LfLD possessed mono-polar flagellum while LfPF was unflagellated. When LfLD was cultured at 25, 30 and 37 °C, the bacteria had higher motility rate at lower temperatures. Based on our results, this is the first study that showed distinct characteristics between LfPF and LfLD, which may give important leads in elucidating differences in their virulence.

Acinetobacter baumannii Virulence Is Mediated by the Concerted Action of Three Phospholipases D.

Acinetobacter baumannii causes a broad range of opportunistic infections in humans. Its success as an emerging pathogen is due to a combination of increasing antibiotic resistance, environmental persistence and adaptation to the human host. To date very little is known about the molecular basis of the latter. Here we demonstrate that A. baumannii can use phosphatidylcholine, an integral part of human cell membranes, as sole carbon and energy source. We report on the identification of three phospholipases belonging to the PLD superfamily. PLD1 and PLD2 appear restricted to the bacteria and display the general features of bacterial phospholipases D. They possess two PLDc_2 PFAM domains each encompassing the HxKx4Dx6GS/GGxN (HKD) motif necessary for forming the catalytic core. The third candidate, PLD3, is found in bacteria as well as in eukaryotes and harbours only one PLDc_2 PFAM domain and one conserved HKD motif, which however do not overlap. Employing a markerless mutagenesis system for A. baumannii ATCC 19606T, we generated a full set of PLD knock-out mutants. Galleria mellonella infection studies as well as invasion experiments using A549 human lung epithelial cells revealed that the three PLDs act in a concerted manner as virulence factors and are playing an important role in host cell invasion.

Intracellular accumulation of indium ions released from nanoparticles induces oxidative stress, proinflammatory response and DNA damage.

Due to the widespread use of indium tin oxide (ITO), it is important to investigate its effect on human health. In this study, we evaluated the cellular effects of ITO nanoparticles (NPs), indium chloride (InCl3) and tin chloride (SnCl3) using human lung epithelial A549 cells. Transmission electron microscopy and inductively coupled plasma mass spectrometry were employed to study cellular ITO NP uptake. Interestingly, greater uptake of ITO NPs was observed, as compared with soluble salts. ITO NP species released could be divided into two types: 'indium release ITO' or 'tin release ITO'. We incubated A549 cells with indium release ITO, tin release ITO, InCl3 or SnCl2 and investigated oxidative stress, proinflammatory response, cytotoxicity and DNA damage. We found that intracellular reactive oxygen species were increased in cells incubated with indium release ITO, but not tin release ITO, InCl3 or SnCl2. Messenger RNA and protein levels of the inflammatory marker, interleukin-8, also increased following exposure to indium release ITO. Furthermore, the alkaline comet assay revealed that intracellular accumulation of indium ions induced DNA damage. Our results demonstrate that the accumulation of ionic indium, but not ionic tin, from ITO NPs in the intracellular matrix has extensive cellular effects.

N-3 Fatty acids regulate the inflammatory-state related genes in the lung epithelial cells exposed to polycyclic aromatic hydrocarbons.

Chronic airway inflammation is coordinated by a complex of inflammatory mediators, including eicosanoids. The aim of this study was to evaluate the impact of polycyclic aromatic hydrocarbons (PAHs) on the human lung epithelial carcinoma A549 cells supplemented with docosahexaenoic (DHA) and eicosapentaenoic (EPA) acids. We analyzed the influence of DHA, EPA and/or benzo(a)pyrene (BaP), chrysene (Chr), fluoranthene (Flu) and benzo(a)anthracene (Baa) treatment on the fatty acids (FAs) profile and the formation of isoprostanes. We studied the cyclooxygenase-2, FP-receptor, peroxisome proliferator-activated receptors PPARδ and PPARγ, transcription factor NF-кB p50 and p65 expression by Western blot, phospholipase A2 (cPLA2) activity, as well as aryl hydrocarbon receptor (AHR), cytochrome P450 (CYP1A1), phospholipase A2 (PLA2G4A) and prostaglandin synthase 2 (PTGS2) gene expression by qRT-PCR. DHA or EPA supplementation and BaP or Baa treatment resulted in a higher level of PGF3α. COX-2 expression was decreased while PPARδ expression and cPLA2 activity was increased after fatty acid supplementation and PAHs treatment. DHA and EPA up-regulated AHR and PLA2G4A genes. Supplementation with n-3 FAs resulted in changes of inflammatory-state related genes in the lung epithelial cells exposed to PAHs. The altered profile of lipid mediators from n-3 FA as well as repression of the COX-2 protein by n-3 PUFAs in A549 cells incubated with PAHs suggests anti-inflammatory and pro-resolving properties of DHA and EPA. It remains to be shown whether these pleiotropic and protective actions of n-3 FAs contribute to fish oil's therapeutic effect in asthma.

ID: 31: The diverse roles of type I interferon in response to EMCV and SeV infections

Type I interferon (IFN) is one of the body’s first line of defense against invading pathogens. The IFN- α subgroup in the type I IFN family consists of 12 different proteins that are known to have antiviral properties. However, the specific functions, efficacies, and induction patterns of each IFN- α subtype in response to viral pathogens have not been fully assessed. This study examines these properties using two RNA viruses, Sendai virus (SeV) and encephalomyocarditis virus (EMCV) and two human cell lines. Using the human lung epithelial cell line A549 and monocytoid cell line U937 we show that IFN- α subtypes are unique in their antiviral properties. IFN- α subtype pretreatment of both cell lines challenged with EMCV results in a range of antiviral activities. Subtype pretreatment followed by SeV challenge, however, did not protect either cell type. A549 cells were shown to induce very little type I IFN RNA upon SeV infection, but this induction results in the upregulation of IFN stimulated genes and biologically active IFN protein. Together, our study shows that IFN- α s have cell type and virus specific functions. The inability of type I IFN to protect against SeV infection must be further explored mechanistically to uncover why biologically active type I IFN is unable to induce an antiviral state.

Methadone enhances human influenza A virus replication.

Growing evidence has indicated that opioids enhance replication of human immunodeficiency virus and hepatitis C virus in target cells. However, it is unknown whether opioids can enhance replication of other clinically important viral pathogens. In this study, the interaction of opioid agonists and human influenza A/WSN/33 (H1N1) virus was examined in human lung epithelial A549 cells. Cells were exposed to morphine, methadone or buprenorphine followed by human H1N1 viral infection. Exposure to methadone differentially enhanced viral propagation, consistent with an increase in virus adsorption, susceptibility to virus infection and viral protein synthesis. In contrast, morphine or buprenorphine did not alter H1N1 replication. Because A549 cells do not express opioid receptors, methadone-enhanced H1N1 replication in human lung cells may not be mediated through these receptors. The interaction of methadone and H1N1 virus was also examined in adult mice. Treatment with methadone significantly increased H1N1 viral replication in lungs. Our data suggest that use of methadone facilitates influenza A viral infection in lungs and might raise concerns regarding the possible consequence of an increased risk of serious influenza A virus infection in people who receive treatment in methadone maintenance programs.

Transcriptome Profiles of Human Lung Epithelial Cells A549 Interacting with Aspergillus fumigatus by RNA-Seq.

Lung epithelial cells constitute the first defense line of host against the inhaled Aspergillus fumigatus; however, the transcriptional response of human alveolar type II epithelial cells was still unclear. Here we used RNA-Seq technology to assess the transcriptome profiles of A549 cells following direct interaction with conidia of A. fumigatus. The total number of identified genes was 19118. Compared with uninfected A549 cells, 459 genes were differentially expressed in cells co-incubated with conidia for 8 h, including 302 up-regulated genes and 157 down-regulated genes. GO and KEGG pathway enrichment analysis showed that most of the up-regulated genes were related to immune response, chemotaxis and inflammatory response and enriched in cytokine-cytokine receptor interaction, JAK-STAT and MAPK signaling pathways. The down-regulated genes were mainly enriched for terms associated with development, hemopoiesis and ion transport. Among them, EGR4 and HIST1H4J gene had the maximum of fold change in up-regulated and down-regulated genes, respectively. Fourteen up-regulated genes and three down-regulated genes were further validated and significant increase on expression of IL-6, IL-8 and TNF-α in A549 cells were confirmed by qRT-PCR during the interaction of A549 cells with A. fumigatus. Besides, western blot showed that expression of two proteins (ARC, EGR1) significantly increased in A549 cells during interaction with A. fumigatus conidia for 8h. Interference of endogenous expression of ARC or EGR1 protein in A549 cells reduced the internalization of A. fumigatus. These results provided important insights into dynamic changes of gene expression in lung epithelial cells, especially its strong immunological response against A. fumigatus infection.

Burkholderia pseudomallei survival in lung epithelial cells benefits from miRNA-mediated suppression of ATG10

Burkholderia pseudomallei is the causative agent of melioidosis, a disease with high mortality, which is prevalent in tropical regions of the world. A recent study shows that B. pseudomallei can survive inside mammalian cells because of its ability to actively evade cell autophagy. However, the underlying mechanisms remain unclear. In the present study, based on microarray screening, we found that ATG10 was downregulated following B. pseudomallei infection in A549 human lung epithelial cells. Forced expression of ATG10 accelerated the elimination of intracellular B. pseudomallei by enhancing the process of autophagy. Moreover, MIR4458, MIR4667-5p, and MIR4668-5p were found, by microarray screening, to be upregulated in response to B. pseudomallei infection. These 3 novel miRNAs, MIR4458, MIR4667-5p, and MIR4668-5p, targeted to the 3′-untranslated region of ATG10 in different time-course and spatial manners. Upregulation of these miRNAs reduced the level of ATG10 and inhibited autophagy, leading to increasing survival rate of intracellular B. pseudomallei. Furthermore, the increase of these miRNAs was correlated with the reduced promoter methylation status in A549 cells in response to B. pseudomallei infection. Our results reveal that 3 novel miRNAs regulate autophagy-mediated elimination of B. pseudomallei by targeting ATG10, and provide potential targets for clinical treatment.

Formulation of Biologically-Inspired Silk-Based Drug Carriers for Pulmonary Delivery Targeted for Lung Cancer.

The benefits of using silk fibroin, a major protein in silk, are widely established in many biomedical applications including tissue regeneration, bioactive coating and in vitro tissue models. The properties of silk such as biocompatibility and controlled degradation are utilized in this study to formulate for the first time as carriers for pulmonary drug delivery. Silk fibroin particles are spray dried or spray-freeze-dried to enable the delivery to the airways via dry powder inhalers. The addition of excipients such as mannitol is optimized for both the stabilization of protein during the spray-freezing process as well as for efficient dispersion using an in vitro aerosolisation impactor. Cisplatin is incorporated into the silk-based formulations with or without cross-linking, which show different release profiles. The particles show high aerosolisation performance through the measurement of in vitro lung deposition, which is at the level of commercially available dry powder inhalers. The silk-based particles are shown to be cytocompatible with A549 human lung epithelial cell line. The cytotoxicity of cisplatin is demonstrated to be enhanced when delivered using the cross-linked silk-based particles. These novel inhalable silk-based drug carriers have the potential to be used as anti-cancer drug delivery systems targeted for the lungs.