Novel soybean polypeptide dglycin alleviates atherosclerosis in apolipoprotein E-deficient mice

Atherosclerosis is a dominant cause of cardiovascular disease. Accumulation of low-density lipoproteins (LDL), formation of foam cells, and endothelial dysfunction within the arterial intima contribute to atherosclerotic plaque formation. Soy consumption is thought to have positive effect on the prevention of atherosclerosis. Therefore, in the present study, a novel soybean polypeptide dglycin was purified and characterized. Oral administration of 20 mg/g.d dglycin reduced 47.6 % lesion area, and 49.1 % lipid deposition in the atherosclerotic plaques in aortic roots in ApoE^-/- mice. In addition, it decreased the levels of 26.0 % plasma low-density lipoprotein, 27.2 % triglyceride, 40.1 % cholesterol, 25.1 % malondialdehyde and 24.2 % tumor necrosis factor-alpha (TNFα). In vitro experiments revealed that dglycin inhibited inflammatory cytokine secretion from aortic endothelial cells via the inhibition of NF-κB signaling. Furthermore, it inhibited reactive oxygen species generation, subsequently enhanced cell viability, and protected aortic endothelial cells from necrosis and apoptosis via mitochondrial function improvement. On the other hand, dglycin prevented the uptake of oxidized LDL by macrophages via suppressing the expression of scavenger receptor class A1, which suggested that dglycin prevented foam cell formation. Therefore, dglycin alleviated the early-stage of atherosclerosis via depressing inflammation, lipid deposition, protecting aortic endothelial cells and preventing foam cell formation.