Anti-inflammatory effects of artesunate on atherosclerosis via miR-16-5p and TXNIP regulation of the NLRP3 inflammasome

BACKGROUND: Atherosclerosis (AS) is chronic inflammatory arterial disorder. Artesunate could exhibit anti-inflammatory activity in AS, but its role in AS is still in its incipient stage. In this study, we explored the anti-inflammatory effect of artesunate in AS and its underlying mechanism. METHODS: We isolated CD14(+) monocytes from peripheral blood (PB) of 115 coronary heart disease (CHD) patients and 33 non-CHD patients confirmed by coronary angiography. Phorbol myristate acetate (PMA) was used to induce the differentiation of THP-1 monocytes to macrophages. Cells were treated with artesunate at a final concentration of 2.5, 5 or 10 µmol/L. The activation of NLRP3 inflammasome was assessed by immunoblotting of apoptosis-associated speck-like protein containing caspase recruitment domain (ASC). The expression of pro-caspase-1/pro-interleukin (IL)-1β/pro-IL-18 and their mature forms was measured using immunoblotting. A rat model of AS was induced by vitamin D3 (VD3) and a 21-day high-fat diet. RESULTS: Downregulated miR-16-5p and upregulated thioredoxin-interacting protein (TXNIP) was determined in CD14(+) monocytes from CHD patients and associated with disease severity. Artesunate abrogated the activation of NLRP3 inflammasome in the presence of inflammasome activators in cultured macrophages. Artesunate reduced TXNIP expression and impaired the interaction between TXNIP and NLRP3, thereby inhibiting release of inflammatory cytokines and ASC production in cultured macrophages. In addition, miR-16-5p negatively regulated the messenger RNA (mRNA) of TXNIP. Artesunate increased the expression of miR-16-5p in a dose-dependent manner, and inhibition of miR-16-5p enhanced the secretion of inflammatory cytokines. Our in vivo experiments also demonstrated that artesunate reduced lipid accumulation, atherosclerotic plaque formation, and antagonized inflammation in a dose-dependent manner by upregulating miR-16-5p. CONCLUSIONS: In summary, the present study unveiled a mechanism underlying the anti-inflammatory role of artesunate in AS.