MiR-223 plays a protecting role in neutrophilic asthmatic mice through the inhibition of NLRP3 inflammasome.

BACKGROUND:Neutrophilic subtype asthma occurs in approximately 15-25% of the asthma cases and is associated with severe airflow obstruction, corticosteroid resistance. MicroRNA plays a vital role in regulating many immune processes, but how miRNA circuits coordinate airway inflammation during neutrophilic asthma is unclear. METHODS:To investigate the molecular mechanism of miR-223 in regulation of neutrophilic airway inflammation, miR-223 knockout mice were used to the OVA/CFA-induced neutrophilic asthma or treated with NLRP3 inhibitor and IL-1β receptor antagonist. Based on the results obtained, wide-type mice were subsequently treated with miR-223 agomirs or negative control agomirs, and the effects on airway inflammation were assessed using morphometric techniques, quantitative RT-PCR, western blot, ELISA and other molecular approaches. RESULTS:The expression of miR-223 was upregulated in lung tissues of experimental mice model. Furthermore, miR-223^-/- mice led to aggravated neutrophilic airway inflammation with heightened histopathological, inflammatory cells and cytokines readouts. Moreover, miR-223^-/- mice also presented with enhanced NLRP3 inflammasome level with elevated IL-1β. Blocking NLRP3 or IL-1β diminished this phenotype. Finally, overexpression of miR-223 via treatment with miR-223 agomirs attenuated airway inflammation, NLRP3 levels and IL-1β release. CONCLUSIONS:The findings of this study revealed a crucial role for miR-223 in regulating the immunoinflammatory responses by depressing the NLRP3/ IL-1β axis in neutrophilic asthma.

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