Redundant γc cytokines license IL-1-driven neutrophil inflammation through MEK/ERK convergence
Interleukin-1 (IL-1) is a central driver of autoinflammatory disease, yet IL-1 blockade often provides incomplete benefit in complex, neutrophil-driven conditions. Here we identify a licensing circuit in which common {gamma}-chain ({gamma}c) cytokines provide a redundant signal required for maximal IL-1-driven neutrophil inflammation. IL-1 and {gamma}c cytokines synergize to drive inflammatory cytokine production exceeding either stimulus alone, and these signals engage the MEK/ERK pathway, an effect substantially suppressed by pharmacological MEK inhibition. We validated this circuit in vivo in a mouse model of IL-1-driven neutrophil-dominant autoinflammation. Ablation of the shared {gamma}c receptor markedly prolonged survival and attenuated pathology, whereas deletion of individual {gamma}c cytokine pathways had no major effect--demonstrating in vivo necessity and functional redundancy. Analysis of public phospho-proteomic and transcriptomic datasets confirms MEK/ERK as a conserved neutrophil response to diverse inflammatory stimuli and coordinated IL-1, {gamma}c, and MEK/ERK activation in neutrophils from patients with systemic juvenile idiopathic arthritis (sJIA) and in lesional skin from hidradenitis suppurativa. Together, these findings define a signaling architecture in which redundant {gamma}c inputs enhance MEK/ERK-dependent inflammatory output, identify the {gamma}c receptor as an in vivo disease-modifying node, and position MEK/ERK as a mechanistically grounded therapeutic target. eTOC SummaryLorenzo et al. show that common {gamma}-chain ({gamma}c) cytokines provide redundant licensing signals that amplify IL-1-driven neutrophil inflammation through MEK/ERK convergence. Blocking any single {gamma}c cytokine fails to suppress disease, but ablating the shared {gamma}c receptor or inhibiting MEK/ERK markedly attenuates pathology, identifying these nodes as therapeutic targets in autoinflammatory disease.