IL-4 and IL-17 Are Required for House Dust Mite-Driven Airway Hyperresponsiveness in Autoimmune Diabetes-Prone Non-Obese Diabetic Mice

Abstract

Allergic asthma is characterized by airway inflammation with a Th2-type cytokine profile, hyper-IgE production, mucus hypersecretion, and airway hyperreactivity (AHR). It is increasingly recognized that asthma is a heterogeneous disease implicating complex immune mechanisms resulting in distinct endotypes observed in patients. In this study, we showed that non-obese diabetic (NOD) mice, which spontaneously develop autoimmune diabetes, undergo more severe allergic asthma airway inflammation and AHR than pro-Th2 BALB/c mice upon house dust mite (HDM) sensitization and challenge. The use of IL-4-deficient NOD mice and the in vivo neutralization of IL-17 demonstrated that both IL-4 and IL-17 are responsible by the exacerbated airway inflammation and AHR observed in NOD mice. Overall, our findings indicate that autoimmune diabetes-prone NOD mice might become useful as a new HDM-induced asthma model to elucidate allergic dysimmune mechanisms involving Th2 and Th17 responses that could better mimic some asthmatic endoytpes.

Keywords: IL-17; IL-4; NOD mice; airway hyperreactivity; asthma; house dust mite; iNKT cells.

Figure 1

Severe allergic-induced asthma phenotype in non-obese diabetic (NOD) mice. (A) Specific IgG1 in house dust mite (HDM)-treated BALB/c and NOD mice (n=9). (B) Percentage of eosinophils and macrophage (Mac), eosinophil (Eos), neutrophil (Neu), and lymphocyte (Lym) counts were determined in BALF of HDM-treated BALB/c and NOD mice (n=15). No eosinophils were detected in the lung of control mice. (C) Lung resistance was measured 24h after the last challenge with HDM or saline (n=10). (D) IL-4, IL-5, IL-13, and mucin messenger RNA (mRNA) expression assessed by quantitative RT-PCR in the lung of HDM-treated BALB/c and NOD mice (n=9). (E) Representative PAS-stained lung histology sections of saline controls and HDM-treated BALB/c and NOD mice (N=5). Statistical significance was determined between HDM-treated BALB/c and NOD mice. *p < 0.05, **p < 0.01, ***p < 0.001. Scale bars: 50µm.

Figure 2

Activation and cytokine production by lung ILT and conventional T cells in house dust mite (HDM)-treated BALB/c versus non-obese diabetic (NOD) mice. (A, B) Percentage of lung invariant natural killer T (iNKT) cells among gated T cells (A) and of IL-4⁺ and IL-17⁺ cells among gated iNKT cells (B). (C) Percentage of lung γδ T or Vγ1⁺ γδ T cells among gated T cells. (D) Percentage of lung IL-4⁺ and IL-17⁺ cells among gated Vγ1⁺ γδ T cells. (E) Percentage of CD44⁺CD69⁺ among gated CD4⁺ T cells in BALF from HDM-treated mice. No CD4+ T cells were observed in BALF from control mice. (F) Percentage of lung IL-4⁺, IL-13⁺, and IL-17⁺ cells among gated CD4⁺ T cells. Light circles and squares represent BALB/c and NOD control mice, respectively. Dark circles and squares represent BALB/c HDM and NOD HDM mice, respectively. *p < 0.05, **p < 0.01, ****p < 0.0001.

Figure 3

Reduced airway inflammation in non-obese diabetic (NOD) IL-4KO mice. (A, B) Percentage and number of macrophages (Mac), eosinophils (Eos), neutrophils (Neu), and lymphocytes (Lym) in BALF of HDM-treated NOD and NOD IL-4KO mice (n=7). (C) Representative periodic acid Schiff (PAS)-stained lung histology sections of HDM-treated NOD and NOD IL-4KO mice (N=5). (D) Mucin mRNA expression assessed by quantitative RT-PCR in lung of HDM-treated NOD and NOD IL-4KO and NOD control mice (n=9). (E) Lung resistance was measured 24h after the last challenge with HDM challenge or saline (n=10). *p < 0.05, **p < 0.01, ***p < 0.001. Scale bars: 50µm.

Figure 4

IL-4 and IL-17 are required for the development of airway inflammation in non-obese diabetic (NOD) mice. (A) IL-17 messenger RNA (mRNA) expression assessed by quantitative RT-PCR in lung of HDM-treated NOD and NOD IL-4KO mice (n=4 to 6). (B) Percentage of eosinophils and neutrophils in bronchoalveolar lavage fluid (BALF) of house dust mite (HDM)-treated NOD IL-4KO mice treated with anti-IL-17 or Ig control (n=6 to 9). (C) IL-5 and IL-13 mRNA expression assessed by quantitative RT-PCR in lung of HDM-treated NOD IL-4KO mice treated with anti-IL-17 or Ig control (n=4 to 6). (D) Lung resistance was measured 24h after the last HDM challenge or controls (NaCl) (n=6 to 8). *p < 0.05, **p < 0.01, ***p < 0.001.