Alternaria-Induced Release of IL-18 from Damaged Airway Epithelial Cells: An NF-κB Dependent Mechanism of Th2 Differentiation?

Background

A series of epidemiologic studies have identified the fungus Alternaria as a major risk factor for asthma. The airway epithelium plays a critical role in the pathogenesis of allergic asthma. These reports suggest that activated airway epithelial cells can produce cytokines such as IL-25, TSLP and IL-33 that induce Th2 phenotype. However the epithelium-derived products that mediate the pro-asthma effects of Alternaria are not well characterized. We hypothesized that exposure of the airway epithelium to Alternaria releasing cytokines that can induce Th2 differentiation.

Methodology/Principal Finding

We used ELISA to measure human and mouse cytokines. Alternaria extract (ALT-E) induced rapid release of IL-18, but not IL-4, IL-9, IL-13, IL-25, IL-33, or TSLP from cultured normal human bronchial epithelial cells; and in the BAL fluids of naïve mice after challenge with ALT-E. Both microscopic and FACS indicated that this release was associated with necrosis of epithelial cells. ALT-E induced much greater IL-18 release compared to 19 major outdoor allergens. Culture of naïve CD4 cells with rmIL-18 induced Th2 differentiation in the absence of IL-4 and STAT6, and this effect was abrogated by disrupting NF- κB p50 or with a NEMO binding peptide inhibitor.

Conclusion/Significance

Rapid and specific release of IL-18 from Alternaria-exposed damaged airway epithelial cells can directly initiate Th2 differentiation of naïve CD4⁺ T-cells via a unique NF-κB dependent pathway.     

A genome-wide study of cytogenetic changes in colorectal cancer using SNP microarrays: opportunities for future personalized treatment

In colorectal cancer (CRC), chromosomal instability (CIN) is typically studied using comparative-genomic hybridization (CGH) arrays. We studied paired (tumor and surrounding healthy) fresh frozen tissue from 86 CRC patients using Illumina's Infinium-based SNP array. This method allowed us to study CIN in CRC, with simultaneous analysis of copy number (CN) and B-allele frequency (BAF)--a representation of allelic composition. These data helped us to detect mono-allelic and bi-allelic amplifications/deletion, copy neutral loss of heterozygosity, and levels of mosaicism for mixed cell populations, some of which can not be assessed with other methods that do not measure BAF. We identified associations between CN abnormalities and different CRC phenotypes (histological diagnosis, location, tumor grade, stage, MSI and presence of lymph node metastasis). We showed commonalities between regions of CN change observed in CRC and the regions reported in previous studies of other solid cancers (e.g. amplifications of 20q, 13q, 8q, 5p and deletions of 18q, 17p and 8p). From Therapeutic Target Database, we identified relevant drugs, targeted to the genes located in these regions with CN changes, approved or in trials for other cancers and common diseases. These drugs may be considered for future therapeutic trials in CRC, based on personalized cytogenetic diagnosis. We also found many regions, harboring genes, which are not currently targeted by any relevant drugs that may be considered for future drug discovery studies. Our study shows the application of high density SNP arrays for cytogenetic study in CRC and its potential utility for personalized treatment.     

Computational validation of 3-ammonio-3-(4-oxido- 1H-imidazol-1-ium-5-yl) propane-1, 1-bis (olate) as a potent anti-tubercular drug against mt-MetAP

The advent of Multi Drug Resistant (MDR) strain of Mycobacterium tuberculosis (TB) necessitated search for new drug targets for the bacterium. It is reported that 3.3% of all new tuberculosis cases had multidrug resistance (MDR-TB) in 2009 and each year, about 0.44 million MDR-TB cases are estimated to emerge and 0.15 million people with MDR-TB die. Keeping such an alarming situation under consideration we wanted to design suitable anti tubercular molecules for new target using computational tools. In the work Methionine aminopeptidase (MetAP) of Mycobacterium tuberculosis was considered as target and three non-toxic phenolic=ketonic compounds were considered as ligands. Docking was done with Flex X and AutoDock 4.2 separately. Ten proven inhibitors of MetAP were collected from literature with their IC50 and were correlated using EasyQSAR to generate QSAR model. Activity of ligands in question was predicted from QSAR. Pharmacophore for each docking was generated using Ligandscout 3.0. Toxicity of the ligands in question was predicted on Mobyle@rpbs portal and Actelion property explorer. Molecular docking with target showed that of all three ligands, 3-ammonio-3-(4-oxido-1H-imidazol-1-ium-5-yl) propane-1, 1-bis (olate) has highest affinity (- 37.5096) and lowest IC50 (4.46 µM). We therefore, propose that -3-ammonio-3-(4-oxido-1H-imidazol-1-ium-5-yl) propane-1,1- bis(olate) as a potent MetAP inhibitor may be a new anti-tubercular drug particularly in the context of Multi Drug Resistant Tuberculosis (MDR-TB).     

Nitric oxide synthase inhibitor and IL-18 enhance the anti-tumor immune response of rats carrying an intrahepatic colon carcinoma

The role of nitric oxide (NO) produced by adherent spleen cells in the systemic immunosuppression developing in tumor-bearing hosts was investigated. After therapeutic immunization of rats carrying an intrahepatic colon carcinoma, H1D2, the spleen cell antitumor immune responsiveness was analyzed. Compared to parallel immunized tumor-free rats, tumor-bearing rats (TB rats) had a greatly reduced proliferative T-cell response to wild-type tumor stimulator cells. The TB rats had a depressed proliferative response to anti-CD3 and to the superantigen SEA. TB rats with small tumors had a stronger response to IL-18-producing H1D2 stimulator cells than to wild type H1D2 cells. This was not the case with TB rats carrying larger tumors. Also the IFN-gamma production and cytotoxicity against the wild-type tumor cells and the NK sensitive YAC cells were depressed in spleen cells of TB rats after 5-day restimulation with wild-type tumor cells. A part of this immunosuppression was mediated by adherent spleen cells, mostly consisting of macrophages. An important mode of action appears to involve their production of an enhanced level of nitric oxide, since the competitive nitric oxide synthase (NOS) inhibitor L-NAME could partially counteract the suppression in vitro. We conclude that NOS inhibitors in combination with immunostimulatory cytokines, such as IL-18, could be useful tools to enhance anti-tumor immune responses in TB rats and therefore to increase the efficiency of immunotherapies.     

Effects of growth rate and methotrexate on folate polyglutamates and folylpolyglutamate hydrolase activity in Krebs ascites cells

The activity of folylpolyglutamate hydrolase was measured throughout intraperitoneal growth of Krebs ascites cells in mice and after exposure to methotrexate. Hydrolase activity was lowest during the log phase of growth. Methotrexate administered intraperitoneally during log growth caused a dose- and time-dependent increase in hydrolase activity. Modest changes were observed in endogenous folate polyglutamate chain length distributions throughout growth and upon exposure to methotrexate, but these changes could not be correlated with hydrolase activity.     

Survey of termite-inhabited soil and mosquito breeding sites in Lucknow,India for potential mycopathogens of Anopheles stephensi

A mycological survey was carried out on the fruit surface of Indian jujube during its growth period (before harvest). A total of 32 microfungi belonging to 20 genera were isolated by surface washing technique. Artificial inoculations with the isolated myco-propagules were also performed in mature jujube fruits and most of them were able to cause rot of varying severity. However, Monodictys castaneae, Eupenicillium lapidosum, Paecilomyces fumosoroseus, Trichurus spiralis and Acremonium spp., although present on the fruit surface, were not able to cause rot, indicating lack of specific macerating enzymes necessary for postharvest pathogenesis. This revised version was published online in June 2006 with corrections to the Cover Date.