Caffeic acid, but not ferulic acid, inhibits macrophage pyroptosis by directly blocking gasdermin D activation

Regulated pyroptosis is critical for pathogen elimination by inducing infected cell rupture and pro‐inflammatory cytokines secretion, while overwhelmed pyroptosis contributes to organ dysfunction and pathological inflammatory response. Caffeic acid (CA) and ferulic acid (FA) are both well‐known antioxidant and anti‐inflammatory phenolic acids, which resemble in chemical structure. Here we found that CA, but not FA, protects macrophages from both Nigericin‐induced canonical and cytosolic lipopolysaccharide (LPS)‐induced non‐canonical pyroptosis and alleviates LPS‐induced mice sepsis. It significantly improved the survival of pyroptotic cells and LPS‐challenged mice and blocked proinflammatory cytokine secretion. The anti‐pyroptotic effect of CA is independent of its regulations in cellular lipid peroxidation, mitochondrial function, or pyroptosis‐associated gene transcription. Instead, CA arrests pyroptosis by directly associating with gasdermin D (GSDMD) and blocking its processing, resulting in reduced N‐GSDMD pore construction and less cellular content release. In LPS‐induced septic mice, CA inhibits GSDMD activation in peritoneal macrophages and reduces the serum levels of interleukin‐1β and tumor necrosis factor‐α as the known pyroptosis inhibitors, disulfiram and dimethyl fumarate. Collectively, these findings suggest that CA inhibits pyroptosis by targeting GSDMD and is a potential candidate for curbing the pyroptosis‐associated disease.