The Reducing Effects of Pyrogallol-Phloroglucinol-6,6-Bieckol on High-Fat Diet-Induced Pyroptosis in Endothelial and Vascular Smooth Muscle Cells of Mice Aortas

Abstract

In hyperlipidemia, pyroptosis in endothelial cells (ECs) induces atherosclerosis via the toll-like receptor 4 (TLR4) pathway. We evaluated the effects of Ecklonia cava extract (ECE) and pyrogallol-phloroglucinol-6,6-bieckol (PPB) on pyroptosis of ECs and vascular smooth muscle cells (VSMCs), which leads to attenuation of these cells and dysfunction of the aorta in high-fat-diet (HFD)-fed mice and in palmitate-treated ECs and VSMCs. The expression of TLR4 and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), which induce formation of NOD-LRR-and pyrin domain-containing protein 3 (NLRP3) inflammasomes, were increased by HFD and were decreased by ECE and PPB. The TLR4/NF-κB pathway was upregulated in palmitate-treated ECs and VSMCs and was decreased by ECE and PPB. The expressions of NLRP3/apoptosis-associated speck like protein containing a caspase recruitment domain, caspase-1, interleukin (IL)-1β, and IL-18 were increased by HFD and were decreased by ECE and PPB. Pyroptotic cells were increased by HFD and decreased by ECE and PPB. The expressions of the adhesion molecules, intercellular adhesion molecule and vascular cell adhesion molecule, and endothelin-1 were increased by HFD and were decreased by ECE and PPB. ECE and PPB decreased pyroptosis in the ECs and VSMCs, which was induced by HFD in the mouse aorta, and attenuated EC and VSMC dysfunction, an initiation factor of atherosclerosis.