TNF/TNFR1 axis restrains inflammation-suppressive myeloid subclusters to drive acute pancreatitis.

Acute pancreatitis (AP) is a pancreatic inflammatory disorder that can progress to fatal systemic inflammation and multiorgan failure. Although tumor necrosis factor (TNF) signaling is a key regulator of inflammation, its contribution to AP progression and its therapeutic potential remain incompletely understood. We induced AP in wild-type and Tnfr1-/- mice using caerulein, pancreatic duct ligation, or L-arginine. Single-cell RNA sequencing (scRNA-seq) and bulk RNA sequencing were used to characterize pancreatic immune-cell profiles, and pomalidomide, infliximab, and necrostatin-1 were evaluated as pharmacological interventions targeting the TNF/TNFR1 pathway. Analysis of public scRNA-seq datasets revealed activation of the TNF/TNFR1 axis across three AP models, accompanied by increased TNF-α and TNFR1 expression. Tnfr1 deletion markedly attenuated pancreatic injury and inflammatory-cell infiltration. scRNA-seq of pancreatic tissues further revealed substantial remodeling of the immune landscape in Tnfr1-/- mice, including reductions in myeloid cells and neutrophils. Within the Neu_C3 neutrophil subset, NF-κB and TNF signaling and neutrophil extracellular trap formation were suppressed. Integrated analysis with bulk RNA-seq showed reduced expression of Marcksl1, Ifit3, and Oas3 in the Neu_C3 cluster, with further reductions following TNFR1 ablation. Tnfr1 deletion also reduced M1 macrophage polarization and expanded an Igkc-high myeloid subcluster characterized by suppressed chemokine signaling. Among the three compounds tested, pomalidomide showed the strongest preventive and therapeutic effects across the experimental AP models. Together, these findings indicate that the TNF/TNFR1 axis promotes AP by shaping inflammatory myeloid-cell states. Targeting this pathway, particularly with pomalidomide, may provide a therapeutic strategy for AP by remodeling immune-cell populations and suppressing inflammation.