Emodin Suppresses NLRP3/GSDMD-induced Inflammation via the TLR4/MyD88/NF-κB Signaling Pathway in Atherosclerosis

Inflammatory responses induced by NLRP3 inflammasome contribute to the progression of atherosclerosis. This study seeks to investigate the effect of emodin on the NLRP3 inflammasome in atherogenesis and to probe the underlying mechanism.

ApoE-knockout (ApoE^-/-) mice were treated with a high-fat diet (HFD) for 12 weeks and intragastrically with emodin for 6 weeks. Human mononuclear cell line THP-1 was pretreated with emodin or signaling pathway inhibitors and induced into macrophages using phorbol 12-myristate 13-acetate (PMA) for 48 h. The NLRP3-mediated inflammatory response was studied both in vivo and in vitro. The level of the inflammation was detected by western blot, real-time PCR analysis, and ELISA.

Emodin attenuated atherosclerotic lesions in HFD-treated ApoE^-/- mice. Emodin dramatically decreased the expression of NLRP3, GSDMD, IL-1β, and IL-18 in HFD-treated ApoE^-/- mice and PMA-induced macrophages. Moreover, emodin significantly hindered the activation of nuclear factor kappa-B (NF-κB) by inhibiting the formation of the TLR4/MyD88 complex in PMA-induced macrophages.

Our data demonstrate that emodin can inhibit the development of atherosclerotic plaques by alleviating NLRP3/GSDMD-induced inflammation through repressing the TLR4/MyD88/NF-κB signaling pathway in macrophages. This finding suggests that emodin can be a potential candidate for the treatment of atherosclerosis.