Iron Restriction Alleviates Atherosclerosis in ApoE KO Mice: An iTRAQ Proteomic Analysis

Abstract

The “iron hypothesis” of atherosclerosis has long been controversial. Several studies have shown that dietary iron restriction or low-iron diets can effectively alleviate atherosclerosis in rabbits and mice. However, the underlying molecular mechanisms of these phenomena remain to be elucidated. In this study, we further evaluated possible correlations between a low-iron diet and atherosclerosis alleviation by using a quantitative proteomic approach. For this purpose, apolipoprotein E knockout (ApoE KO) mice were divided into three groups and fed a normal diet (ND), a high-fat diet (HFD), or a high-fat +low-iron diet (HFD + LI). Our results showed that the HFD-LI improved atherosclerosis by decreasing en face lesions of the aorta and reducing the accumulation of macrophages and disordered smooth muscle cells. HFD-LI also decreased iron levels, serum hepcidin levels and the serum concentration of low-density lipoprotein cholesterol (LDL-C). The use of the isobaric tag for absolute quantification (iTRAQ) proteomic method and subsequent multi-technique molecular validation indicated that many of the proteins involved in atherosclerotic inflammation, vascular remodeling, and focal adhesion had significant changes in their expression among the diet groups. Importantly, the proteins Gal-3 and VCAM1, which are key participants of atherosclerosis pathogenesis, revealed lower expression after a low-iron diet. The present findings widely support the “iron hypothesis” of atherosclerosis. Further studies are suggested to fully understand the implications of these results.