LPS-induced extracellular AREG triggers macrophages pyroptosis through EGFR/TLR4 signaling pathway

Abstract Amphiregulin (AREG), as another EGF family member, is anchored to the cell surface as a transmembrane protein. In response to external stimulus, its extracellular domain can be release to extracellular matrix in a paracrine or autocrine manner. However, what it plays in septic macrophages pyroptosis remain poorly understood. The role of extracellular AREG was investigated in septic macrophages, mice as well as patients. Here, we found that AREG highly expressed in sepsis increased the expression of IL-6 protein and the expression of Caspase 1, IL-1β, Nlrp3 mRNA, resulting in macrophages pyroptosis. Mechanistically, macrophages pyroptosis was aggravated by extracellular AREG pretreatment and triggered by extracellular AREG and ATP (Adenosine 5'-triphosphate). The neutralizing antibody to AREG reduced LPS-induced EGFR activation, TLR4 expression and pyroptosis. Extracellular AREG-induced macrophages pyroptosis was decreased after applying inhibitions of EGFR and NF-κB as well as knockouts of TLR4 and Myd88. Besides, oxidative extracellular AREG promotes macrophages pyroptosis. In vivo studies reveal that extracellular AREG attenuates systemic inflammation infiltration and delays animal death in septic mouse model. Furthermore, serum AREG was associated with the immune inflammatory mediator, severity and mortality rate of septic patients, and genes of AREG-mediated pyroptosis signaling pathway were highly expressed in severe patients compared normal and general septic patients. Overall, extracellular AREG aggravated or triggered macrophages pyroptosis through EGFR/TLR4/Myd88/NF-κB signaling pathway, which provided promising treatment strategies for sepsis.