Effect of ISO-1 and dexamethasone on ozone-induced changes in AHR and lung function.

<p>Mouse lung function measurements of pulmonary resistance (R_L; A), -logPC₁₀₀ (B), FEV₇₅ (C), lung compliance (C_chord; D), total lung capacity (TLC; E) and functional residual capacity (FRC; F). Data are expressed as mean±SD for 6 animals per group. *<i>p</i><0.05 and **<i>p</i><0.01 compared to air controls, ^#<i>p</i><0.05 compared to ozone-exposed group.</p

Effect of ISO-1 and dexamethasone on ozone-induced BAL inflammation.

<p>Cytokine protein levels in mouse BAL of ozone exposed and ISO-1- or dexamethasone-treated mice measured by ELISA. KC (A), GM-CSF (B), TNF-α (C) and MIF (D). Data are expressed as mean±SD for 6 animals per group. *<i>p</i><0.05 and **<i>p</i><0.01 compared to air controls, # <i>p</i><0.05 compared to ozone exposed group.</p

Effect of ISO-1 and dexamethasone on ozone-induced lung inflammation.

<p>Cytokine mRNA (A, C, E & G) and protein (B, D, F & H) expression levels in the lung of ozone exposed and ISO-1- or dexamethasone-treated mice. KC (A&B), GM-CSF (C&D), TNF-α (E&F), and MIF (G&H). Data are expressed as mean±SD for 6 animals per group. *<i>p</i><0.05 and **<i>p</i><0.01 compared to air controls, ^#<i>p</i><0.05 compared to ozone exposed group.</p

Effect of ISO-1 and dexamethasone in combination on ozone-induced lung inflammation.

<p>Cytokine mRNA (A & C) and protein (B & D) expression levels in the lung of ozone exposed and the combination of ISO-1- plus dexamethasone-treated mice. KC (A&B) and MIF (C&D). Pulmonary resistance (R_L; E) was also measured. Data are expressed as mean±SD for 6 animals per group. *<i>p</i><0.05 and **<i>p</i><0.01 compared to air controls, ^#<i>p</i><0.05 compared to ozone exposed group.</p

Change in soluble fractalkine in BAL fluid during experimental <i>in vivo</i> RV16 infection, related with upper respiratory symptom scores.

<p>Soluble fractalkine protein was measured in filtered BAL fluid collected at baseline and day 4 post RV16 infection from non-asthmatic (n = 10), mild-asthmatic (n = 11) and moderate-asthmatic (n = 14) subjects. (A) Data is presented as soluble fractalkine (pg/mL) per subject and horizontal bars for median levels for each group in BAL fluid obtained at baseline and day 4. Data were analysed within groups by Wilcoxon-matched pairs signed rank tests and between groups by Mann Whitney U test, *P<0.05. (B) Levels of fractalkine in BAL fluid on Day 4 were correlated with peak upper respiratory symptom scores for each subject infected using Pearson’s correlation (r = 0.289, <i>P</i> = 0.098).</p

Change in levels of fractalkine in PBMCs following <i>in vitro</i> infection with RV16 and RV1B.

<p>Soluble fractalkine protein was measured in cell supernatants from PBMCs obtained from (A) non-asthmatic (n = 15) and (B) asthmatic (n = 15) subjects and compared between subject groups at 8hrs post infection (C). Fractalkine mRNA expression was measured in PBMC cell lysate cDNA obtained from (D) non-asthmatic and (E) asthmatic subjects. The results are expressed as mean ± SEM. Protein data were analysed by one-way ANOVA with Bonferroni post-test and mRNA by Kruskal Wallis with Dunn’s post test (*<i>P</i><0.05, ***<i>P</i><0.001).</p

Change in levels of fractalkine in BAL cells following <i>in vitro</i> infection with RV16 and RV1B.

<p>Soluble fractalkine protein was measured in cell supernatants from BAL cells obtained from (A) non-asthmatic (n = 15) and (B) asthmatic (n = 15) subjects and compared between subject groups at 8hrs post infection (C). Fractalkine mRNA expression was measured in BAL cell lysate cDNA obtained from non-asthmatic (D) and asthmatic (E) subjects. The results are expressed as mean ± SEM. Protein data were analysed by one-way ANOVA with Bonferroni post-test and mRNA by Kruskal Wallis with Dunn’s post test (**<i>P</i><0.01).</p

IL-33-dependent type 2 inflammation during rhinovirus-induced asthma exacerbations in vivo

Rationale: Rhinoviruses are the major cause of asthma exacerbations; however, its underlying mechanisms are poorly understood. We hypothesized that the epithelial cell–derived cytokine IL-33 plays a central role in exacerbation pathogenesis through augmentation of type 2 inflammation. Objectives: To assess whether rhinovirus induces a type 2 inflammatory response in asthma in vivo and to define a role for IL-33 in this pathway. Methods: We used a human experimental model of rhinovirus infection and novel airway sampling techniques to measure IL-4, IL-5, IL-13, and IL-33 levels in the asthmatic and healthy airways during a rhinovirus infection. Additionally, we cultured human T cells and type 2 innate lymphoid cells (ILC2s) with the supernatants of rhinovirus- infected bronchial epithelial cells (BECs) to assess type 2 cytokine production in the presence or absence of IL-33 receptor blockade. Measurements and Main Results: IL-4, IL-5, IL-13, and IL-33 are all induced by rhinovirus in the asthmatic airway in vivo and relate to exacerbation severity. Further, induction of IL-33 correlates with viral load and IL-5 and IL-13 levels. Rhinovirus infection of human primary BECs induced IL-33, and culture of human T cells and ILC2s with supernatants of rhinovirus-infected BECs strongly induced type 2 cytokines. This induction was entirely dependent on IL-33. Conclusions: IL-33 and type 2 cytokines are induced during a rhinovirus-induced asthma exacerbation in vivo. Virus-induced IL-33 and IL-33 – responsive T cells and ILC2s are key mechanistic links between viral infection and exacerbation of asthma. IL-33 inhibition is a novel therapeutic approach for asthma exacerbations