Jun-Pyo Choi

Proteomic analysis of outer membrane vesicles derived from Pseudomonas aeruginosa

Pseudomonas aeruginosa, an opportunistic human bacterial pathogen, constitutively secretes outer membrane vesicles (OMVs) into the extracellular milieu. Although recent progress has revealed that OMVs are essential for pathogenesis of P. aeruginosa, their proteins have not been comprehensively analyzed so far. In this study, we identified 338 vesicular proteins with high confidence by five separate LC‐MS/MS analyses. This global proteome profile provides a basis for future studies to elucidate the pathological functions of OMVs from P. aeruginosa.

Vascular endothelial growth factor is a key mediator in the development of T cell priming and its polarization to type 1 and type 17 T helper cells in the airways.

Chronic inflammatory airway diseases including asthma are characterized by immune dysfunction to inhaled allergens. Our previous studies demonstrated that T cell priming to inhaled allergens requires LPS, which is ubiquitously present in household dust allergens. In this study, we evaluated the role of vascular endothelial growth factor (VEGF) in the development of T cell priming and its polarization to Th1 or Th17 cells when exposed to LPS-contaminated allergens. An asthma mouse model was induced by airway sensitization with LPS-contaminated allergens and then challenged with allergens alone. Therapeutic intervention was performed during allergen sensitization. The present study showed that lung inflammation induced by sensitization with LPS-contaminated allergens was decreased in mice with homozygous disruption of the IL-17 gene; in addition, allergen-specific Th17 immune response was abolished in IL-6 knockout mice. Meanwhile, in vivo production of VEGF was up-regulated by airway exposure of LPS. In addition, airway sensitization of allergen plus recombinant VEGF induced both type 1 and type 17 Th cell (Th1 and Th17) responses. Th1 and Th17 responses induced by airway sensitization with LPS-contaminated allergens were blocked by treatment with a pan-VEGF receptor (VEGFR; VEGFR-1 plus VEGFR-2) inhibitor during sensitization. These effects were accompanied by inhibition of the production of Th1 and Th17 polarizing cytokines, IL-12p70 and IL-6, respectively. These findings indicate that VEGF produced by LPS plays a key role in activation of naive T cells and subsequent polarization to Th1 and Th17 cells.

A viral PAMP double-stranded RNA induces allergen-specific Th17 cell response in the airways which is dependent on VEGF and IL-6.

To cite this article: Choi J‐P, Kim Y‐S, Tae Y‐M, Choi E‐J, Hong B‐S, Jeon SG, Gho YS, Zhu Z, Kim Y‐K. A viral PAMP double‐stranded RNA induces allergen‐specific Th17 cell response in the airways which is dependent on VEGF and IL‐6. Allergy 2010; 65: 1322–1330.

15‐lipoxygenase metabolites play an important role in the development of a T‐helper type 1 allergic inflammation induced by double‐stranded RNA

Background We recently demonstrated that the T‐helper type 1 (Th1) immune response plays an important role in the development of non‐eosinophilic inflammation induced by airway exposure of an allergen plus double‐stranded RNA (dsRNA). However, the role of lipoxygenase (LO) metabolites in the development of Th1 inflammation is poorly understood.

TNF-alpha is a key mediator in the development of Th2 cell response to inhaled allergens induced by a viral PAMP double-stranded RNA

Viral pathogen–associated molecular patterns, such as dsRNA, disrupt airway tolerance to inhaled allergens. Specifically, the Th2 and Th17 cell responses are induced by low‐dose dsRNA and the Th1‐dominant response by high‐dose dsRNA.

Oral immunization of haemaggulutinin H5 expressed in plant endoplasmic reticulum with adjuvant saponin protects mice against highly pathogenic avian influenza A virus infection

Pandemics in poultry caused by the highly pathogenic avian influenza (HPAI) A virus occur too frequently globally, and there is growing concern about the HPAI A virus due to the possibility of a pandemic among humans. Thus, it is important to develop a vaccine against HPAI suitable for both humans and animals. Various approaches are underway to develop such vaccines. In particular, an edible vaccine would be a convenient way to vaccinate poultry because of the behaviour of the animals. However, an edible vaccine is still not available. In this study, we developed a strategy of effective vaccination of mice by the oral administration of transgenic Arabidopsis plants (HA-TG) expressing haemagglutinin (HA) in the endoplasmic reticulum (ER). Expression of HA in the ER resulted in its high-level accumulation, N-glycosylation, protection from proteolytic degradation and long-term stability. Oral administration of HA-TG with saponin elicited high levels of HA-specific systemic IgG and mucosal IgA responses in mice, which resulted in protection against a lethal influenza virus infection with attenuated inflammatory symptoms. Based on these results, we propose that oral administration of freeze-dried leaf powders from transgenic plants expressing HA in the ER together with saponin is an attractive strategy for vaccination against influenza A virus.

The microbiome of the lung and its extracellular vesicles in nonsmokers, healthy smokers and COPD patients

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease, and bacterial infection plays a role in its pathogenesis. Bacteria secrete nanometer-sized extracellular vesicles (EVs), which may induce more immune dysfunction and inflammation than the bacteria themselves. We hypothesized that the microbiome of lung EVs might have distinct characteristics depending on the presence of COPD and smoking status. We analyzed and compared the microbiomes of 13 nonsmokers with normal spirometry, 13 smokers with normal spirometry (healthy smokers) and 13 patients with COPD by using 16S ribosomal RNA gene sequencing of surgical lung tissue and lung EVs. Subjects were matched for age and sex in all groups and for smoking levels in the COPD and healthy smoker groups. Each group included 12 men and 1 woman with the same mean age of 65.5 years. In all groups, EVs consistently showed more operational taxonomic units (OTUs) than lung tissue. In the healthy smoker and COPD groups, EVs had a higher Shannon index and a lower Simpson index than lung tissue and this trend was more prominent in the COPD group. Principal component analysis (PCA) showed clusters based on sample type rather than participants’ clinical characteristics. Stenotrophomonas, Propionibacterium and Alicyclobacillus were the most commonly found genera. Firmicutes were highly present in the EVs of the COPD group compared with other samples or groups. Our analysis of the lung microbiome revealed that the bacterial communities present in the EVs and in the COPD group possessed distinct characteristics with differences in the OTUs, diversity indexes and PCA clustering.

Aspirin attenuates the anti-inflammatory effects of theophylline via inhibition of cAMP production in mice with non-eosinophilic asthma.

Theophylline is commonly used to treat severe asthma and chronic obstructive pulmonary disease (COPD) characterized by non-eosinophilic inflammation. Acetyl salicylic acid (ASA) is one of the most widely used medications worldwide, but up to 20% of patients with asthma experience aggravated respiratory symptoms after taking ASA. Here we evaluated the adverse effect of ASA on the therapeutic effect of theophylline in mice with non-eosinophilic asthma. A non-eosinophilic asthma mouse model was induced by airway sensitization with lipopolysaccharide-containing allergen and then challenged with allergen alone. Therapeutic intervention was performed during allergen challenge. Theophylline inhibited lung inflammation partly induced by Th1 immune response. ASA attenuated the beneficial effects of theophylline. However, co-administration of the ASA metabolite salicylic acid (SA) showed no attenuating effect on theophylline treatment. The therapeutic effect of theophylline was associated with increase in cAMP levels, which was blocked by co-treatment of theophylline and ASA. ASA co-treatment also attenuated the anti-inflammatory effects of a specific phosphodiesterase 4 inhibitor. These results demonstrate that ASA reverses anti-inflammatory effects of theophylline, and that ASA exerts its adverse effects through the inhibition of cAMP production. Our data suggest that ASA reverses lung inflammation in patients taking theophylline, although clinical evidence will be needed.

The enhanced expression of IL-17-secreting T cells during the early progression of atherosclerosis in ApoE-deficient mice fed on a western-type diet.

Atherosclerosis is a chronic progressive inflammatory disorder and the leading cause of cardiovascular mortality. Here we assessed the dynamic changes of T-cell-derived cytokines, such as inteferon (IFN)-γ, interleukin (IL)-17 and IL-4, during the progression of atherosclerosis in apolipoprotein E-null (ApoE−/−) mice, to understand the role of immune responses in different stages of atherosclerosis. Male ApoE−/− mice were fed a high-fat, western-type diet (WD: 21% lipid, 1.5% cholesterol) after 5 weeks of age and were compared with C57BL/6 wild-type control mice fed a standard chow diet. Atherosclerotic lesions appeared in the aortic sinus of ApoE−/− mice 4 weeks after WD and the lesions progressed and occupied >50% of the total sinus area 16 weeks after WD. Aortic IL-17 mRNA and protein expression started to increase in ApoE−/− mice after 4 weeks on the WD and peaked at around 8–12 weeks on the WD. In terms of systemic expression of T-cell-derived cytokines, IL-17 production from splenocytes after anti-CD3/CD28 stimuli increased from 4 weeks on the WD, peaked at 12 weeks and returned to control levels at 16 weeks. The production of IFN-γ and IL-4 (Th1 and Th2 cytokines, respectively) from splenocytes was delayed compared with IL-17. Taken together, the present data indicate that Th17 cell response may be involved at an early stage in the development of atherosclerosis.

An important role of tumor necrosis factor receptor‐2 on natural killer T cells on the development of dsRNA‐enhanced Th2 cell response to inhaled allergens

Recent evidence indicates that TNF‐α is a key mediator of the development of dsRNA‐enhanced Th2 cell response to inhaled allergens. Natural killer T (NKT) cells may be a candidate source of Th2‐polarizing cytokines.