Anti-inflammatory role of Artemisia argyi methanol extract by targeting the caspase-11 non-canonical inflammasome in macrophages.

Abstract

Artemisia argyi possesses pharmacological activities against various immunopathological conditions associated with inflammation. This study explored the inhibitory role of Artemisia argyi methanol extract (Aa-ME) in inflammatory responses and the underlying mechanism in macrophages. Caspase-11 non-canonical inflammasome was activated in J774A.1 macrophage by Pam3CSK4 treatment and lipopolysaccharide (LPS) transfection. Aa-ME-mediated in vitro anti-inflammatory action was examined using MTT assay, lactate dehydrogenase (LDH) activity assay, enzyme-linked immunosorbent assay (ELISA), nitric oxide (NO) generation assay, and quantitative real-time polymerase chain reaction (qPCR). Aa-ME-mediated in vivo anti-inflammatory action was examined in LPS-stimulated lethal septic mice. Aa-ME inhibited caspase-11 non-canonical inflammasome-stimulated pyroptosis and the secretion of IL-1β and IL-18 in J774A.1 macrophages. Aa-ME also inhibited NO generation by downregulating inducible NO synthase (iNOS) expression in LPS-primed and caspase-11 non-canonical inflammasome-triggered J774A.1cells. The mechanism study revealed Aa-ME suppressed the auto-proteolytic activation of caspase-11 and gasdermin D (GSDMD) in J774A.1cells and also interfered with caspase-11-mediated direct recognition of LPS. Moreover, Aa-ME alleviated LPS-induced lethal sepsis in mice by increasing their survival rate without significant toxicity. These results suggest a novel mechanism by which Aa-ME alleviates inflammatory responses by deactivating caspase-11 non-canonical inflammasome in macrophages.