Fig. 3: Mettl3 depletion enhances Th2 cell response in allergic airway inflammation via facilitating M2 macrophage activation.

a The mRNA expression of M2-associated markers (n = 4 animals), and (b) CD206 protein levels (n = 3 animals) in alveolar macrophages purified from CRE-induced asthma models were determined, using RT-qPCR and Western blot, respectively. c Flow cytometry analysis of M2 macrophage subpopulation in BALF from experimental models. d The MFI of M2 macrophages was calculated (n = 4 animals). e Representative composite fluorescent images showing the number of M2 macrophages (F4/80⁺ CD206⁺) in lung tissues from experimental models. Total macrophages, M2 macrophages, and nuclei were labeled with F4/80 (red), CD206 (green), and DAPI (blue), respectively. Scale bars: 25 μm. Quantification of the CD206 intensity ratio in macrophages was performed by Image J (bottom) (n = 3 animals). f RT-qPCR showing up-regulated M2-associated chemokines in alveolar macrophages purified from experimental models (n = 4 animals for PBS groups and n = 5 animals for CRE groups). The levels of Th1, Th2, and Th17 cell-associated cytokines in lung homogenates were detected by RT-qPCR (g) (n = 4 animals for PBS groups and n = 5 animals for CRE groups) and ELISA (h) (n = 5 animals), respectively. i, j Flow cytometry analysis of the frequency of CD4⁺ IL-4⁺ Th2 cells and CD4⁺ IFN-gamma⁺ Th1 cells in MLNs from mice (n = 5 animals). Statistical analysis of the data was performed using two-sided unpaired t test with Welch’s correction (h left) or not (a, h right, j), 1-way ANOVA (b, d, e), and 2-way ANOVA (f, g) followed by Tukey’s multiple comparison tests. Data are presented as means ± SEM from one of three independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001; n.s, not significant.