Cathelicidin-related Antimicrobial Peptide Contributes to Host Immune Responses Against Pulmonary Infection with Acinetobacter baumannii in Mice

Acinetobacter baumannii is known for its multidrug antibiotic resistance. New approaches to treating drug-resistant bacterial infections are urgently required. Cathelicidin-related antimicrobial peptide (CRAMP) is a murine antimicrobial peptide that exerts diverse immune functions, including both direct bacterial cell killing and immunomodulatory effects. In this study, we sought to identify the role of CRAMP in the host immune response to multidrug-resistant Acinetobacter baumannii. Wild-type (WT) and CRAMP knockout mice were infected intranasally with the bacteria. CRAMP−/− mice exhibited increased bacterial colony-forming units (CFUs) in bronchoalveolar lavage (BAL) fluid after A. baumannii infection compared to WT mice. The loss of CRAMP expression resulted in a significant decrease in the recruitment of immune cells, primarily neutrophils. The levels of IL-6 and CXCL1 were lower, whereas the levels of IL-10 were significantly higher in the BAL fluid of CRAMP−/− mice compared to WT mice 1 day after infection. In an in vitro assay using thioglycollate-induced peritoneal neutrophils, the ability of bacterial phagocytosis and killing was impaired in CRAMP−/− neutrophils compared to the WT cells. CRAMP was also essential for the production of cytokines and chemokines in response to A. baumannii in neutrophils. In addition, the A. baumannii-induced inhibitor of κB-α degradation and phosphorylation of p38 MAPK were impaired in CRAMP−/− neutrophils, whereas ERK and JNK phosphorylation was upregulated. Our results indicate that CRAMP plays an important role in the host defense against pulmonary infection with A. baumannii by promoting the antibacterial activity of neutrophils and regulating the innate immune responses.

Adjuvanticity of Processed Aloe vera gel for Influenza Vaccination in Mice

The effectiveness of current influenza vaccines is considered suboptimal, and 1 way to improve the vaccines is using adjuvants. However, the current pool of adjuvants used in influenza vaccination is limited due to safety concerns. Aloe vera, or aloe, has been shown to have immunomodulatory functions and to be safe for oral intake. In this study, we explored the potential of orally administered processed Aloe vera gel (PAG) as an adjuvant for influenza vaccines in C57BL/6 mice. We first evaluated its adjuvanticity with a split-type pandemic H1N1 (pH1N1) Ag by subjecting the mice to lethal homologous influenza challenge. Oral PAG administration with the pH1N1 Ag increased survival rates in mice to levels similar to those of alum and MF59, which are currently used as adjuvants in influenza vaccine formulations.Similarly, oral PAG administration improved the survival of mice immunized with a commercial trivalent influenza vaccine against lethal homologous and heterologous virus challenge. PAG also increased hemagglutination inhibition and virus neutralization Ab titers against homologous and heterologous influenza strains following immunization with the split-type pH1N1 Ag or the commercial trivalent vaccine. Therefore, this study demonstrates that PAG may potentially be used as an adjuvant for influenza vaccines.

Depletion of epsilon-COP in the COPI Vesicular Coat Reduces Cleistothecium Production in Aspergillus nidulans

We have previously isolated epsilon-COP, the alpha-COP interactor in COPI of Aspergillus nidulans, by yeast two-hybrid screening. To understand the function of epsilon-COP, the aneA+ gene for epsilon-COP/AneA was deleted by homologous recombination using a gene-specific disruption cassette. Deletion of the epsilon-COP gene showed no detectable changes in vegetative growth or asexual development, but resulted in decrease in the production of the fruiting body, cleistothecium, under conditions favorable for sexual development. Unlike in the budding yeast Saccharomyces cerevisiae, in A. nidulans, over-expression of epsilon-COP did not rescue the thermo-sensitive growth defect of the alpha-COP mutant at 42degrees C. Together, these data show that epsilon-COP is not essential for viability, but it plays a role in fruiting body formation in A. nidulans.

Effect of Epigallocatechin-3-Gallate on PMA-Induced MUC5B Expression in Human Airway Epithelial Cells

OBJECTIVES: Among the inflammatory mediators, phorbol 12-myristate 13-acetate (PMA) is associated with the regulation of MUC5B expression in the airway epithelial cells. Epigallocatechin-3-gallate (EGCG) is the major component of green tea extract. The biological activity of EGCG includes reduction of cholesterol and antioxidant activity, as well as anti-inflammatory effect. However, the precise action mechanism of anti-inflammatory effect of EGCG in the airway epithelial cells has not been fully defined. This study investigates the effect and the brief signaling pathway of EGCG on PMA-induced MUC5B expression in the airway epithelial cells. METHODS: In NCI-H292 airway epithelial cells, the effect and signaling pathway of EGCG on MUC5B expression were investigated using real-time polymerase chain reaction analysis, enzyme immunoassay, immunohistochemical analysis, gelatin zymography assay, and immunoblot analysis. RESULTS: In NCI-H292 airway epithelial cells, PMA induced MUC5B expression, phosphorylation of p38 mitogen-activated protein kinase (MAPK), and matrix metalloproteinase-9 (MMP-9) expression and protein activity. EGCG significantly decreased PMA-induced MUC5B expression, phosphorylation of p38 MAPK, and MMP-9 expression and protein activity. SB203580 (p38 MAPK inhibitor) significantly decreased PMA-induced MMP-9 expression. In addition, SB203580 and MMP-9 I (MMP-9 inhibitor) significantly decreased PMA-induced MUC5B expression. CONCLUSION: These results suggest that EGCG down-regulates PMA-induced MUC5B expression through the p38 MAPK dependent MMP-9 signaling pathway in human airway epithelial cells.