'Blow my mind(in)' - mindin neutralization for the prevention of atherosclerosis?

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.

Promoting plaque stability by gene silencing of monocyte chemotactic protein-3 or overexpression of tissue factor pathway inhibitor in ApoE-/- mice

Chemokines may promote the formation and instability of atherosclerotic plaque, which is the most common cause of acute coronary syndrome. The aim of this study was to clarify the function of monocyte chemotactic protein-3 (MCP-3) in the stability of atherosclerotic plaque, to determine the role of tissue factor pathway inhibitor (TFPI) on the development and stability of atherosclerotic plaques, and to further elucidate the anti-atherosclerotic mechanism of TFPI with the emphasis on chemokine MCP-3. We constructed an adenovirus-mediated shRNA against mouse MCP-3 (Ad-MCP-3-shRNA) and an adenovirus-containing TFPI (Ad-TFPI), and tranferred them in a model of vulnerable plaque in ApoE-/- mice respectively. Here, we reported that MCP-3-shRNA and TFPI could both reduce the plaque area and decrease the content of lipids and macrophages, on the contrary, the fibrous cap thickness and content of collagen and smooth muscle cells were increased. In addition, the expression of MCP-3 and CC chemokine receptor 2 (CCR2) was decreased by TFPI transfer. These data provide the first in vivo evidence that MCP-3 is a major contributor to the unstability of atherosclerotic plaque and TFPI may exert its anti-atherosclerotic effects and promote stabilisation of plaque at least partly through inhibiting MCP-3/CCR2 pathway, which may be a new therapeutic method for atherosclerosis.