[Effects of methionine restriction on allergic airway inflammation].

Objective

To investigate the effects and underlying mechanisms of the methionine-restricted diet（MRD） on type 2 inflammatory airway diseases, and to provide experimental evidence for nutritional interventions in allergic diseases.

Methods

Specific pathogen-free（SPF） C57BL/6J mice were used to establish house dust mite（HDM） -induced allergic rhinitis（AR） and ovalbumin（OVA） -induced asthma models. Mice were randomly assigned to either a MRD（0.12% methionine） group or a standard control diet（CD, 0.86% methionine） group. An additional group receiving MRD alone was included to assess its impact on the peripheral immune system. The in vivo effects of MRD were evaluated through histology（H&E staining）, q-PCR, and flow cytometry. In addition, in vitro Th2 cell differentiation assays were conducted under methionine restriction（MR）.

Results

Compared to the CD group, MRD significantly alleviated nasal mucosal inflammation in the AR model and reduced lung inflammation in the asthma model, along with decreased levels of key type 2 inflammatory cytokines including IL-4, IL-5, IL-13 and so on）. Four weeks of MRD alone did not significantly alter peripheral immune homeostasis. The in vitro experiments further demonstrated that MR directly inhibited the differentiation of nave CD4⁺T cells into Th2 cells.

Conclusion

MRD can suppress Th2 cell-driven allergic airway inflammation while maintaining overall immune homeostasis, offering a potential nutritional intervention strategy for allergic diseases.