IL17A and colitis: Neutrophil-depleted mice developed more severe colitis than controls, characterized by significant weight loss, aggravated histological lesions, impaired mucosal barrier function, and expression of proinflammatory cytokines (e.g., IL-1β, IL-17A, IFN-γ and TNF-α) in the colon tissues (Supplementary Figure S1b-f).