Evidence item

Using a skin infection model with pathogenic bacteria and fungi, we demonstrate that neutrophil recruitment occurs in two sequential phases. The early phase is PRR-independent and instead driven by microbial adhesion, which engages the mechanosensitive ion channel Piezo1 to promote leukotriene (LT)B4 production. Together with interleukin-1α, LTB4 induces CXCL1 release, triggering neutrophil infiltration via the same circuit at play during sterile inflammation. By contrast, the late phase is toll-like receptor (TLR)- and CXCL2-dependent, marking a transition to the canonical, pathogen-driven response.