Figure 6. Attenuated IL-25–induced pulmonary inflammation in Regnase-1^AA/AA mice.

(A) Experimental schema. Regnase-1^WT/WT (blue) and Regnase-1^AA/AA (red) mice were i.n. administered with IL-25 (100 ng/dose) or PBS (control; Cont) for 4 consecutive days. (B–D) Histological examination. Representative H&E staining (B) and Periodic acid–Schiff staining (PAS) (C) of lung left lobes (scale bar: 50 mm) and the quantified pathology scores of IL-25–treated mice (D) are shown. (E) Total numbers of CD45⁺ cells (CD45⁺ singlet cells), eosinophils (CD45⁺autofluorescence^–CD11b⁺Siglec-F⁺), CD11c⁺eosinophils (CD45⁺autofluorescence^–CD11b⁺Siglec-F⁺CD11c⁺), and ST2^–KLRG⁺ ILC2s (CD45⁺Lin^–CD90.2⁺ST2^–KLRG-1⁺) in the lung left lobes were quantified by FACS. (F) Lung cells were stimulated with PMA and ionomycin for 4 hours. The percentage of IL-5– and IL-13–producing cells within CD45⁺Lin^–CD90.2⁺ ILC2s was quantified by intracellular cytokine staining and FACS. (G) mRNA levels for Muc5ac in the lungs were determined by quantitative PCR. Data are representative of 2 independent experiments. Representative images (B and C) and mean (n = 3 for control and n = 6) ± SEM (D–G) are shown. Significance was determined by 2-tailed Student’s t test (D) or 1-way ANOVA followed by Tukey’s test (E–G). *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.