Novel Complexes Link Immune Peptide LL-37 to Heart Disease Risk
Background
The development of atherosclerosis, a chronic inflammatory disease leading to coronary artery disease (CAD), is intricately linked to both lipoprotein metabolism and the innate immune system. Apolipoprotein B-100 (Apo B100), a key structural protein of low-density lipoproteins (LDL), is central to lipid transport and plaque formation, while LL-37 (a human cathelicidin antimicrobial peptide) plays a significant role in immune responses and inflammation. Despite their individual contributions, the precise mechanisms by which LL-37 and Apo B100 interact to influence atherogenesis and CAD risk remain poorly understood.
Results
The study revealed that LL-37 readily forms stable complexes with Apo B100 present in oxLDL, significantly altering cellular responses. In vitro, these complexes led to a 35% increase in lipid accumulation within macrophages compared to oxLDL alone (p<0.01), alongside a 2.5-fold elevation in pro-inflammatory cytokine IL-6 secretion (p<0.005). In vivo, mice treated with LL-37-Apo B100 complexes exhibited a 40% larger atherosclerotic plaque area in the aortic arch compared to control mice (p<0.001). The formation of LL-37-Apo B100 complexes significantly exacerbates macrophage lipid uptake and accelerates atherosclerotic plaque development in a murine model. Furthermore, systemic levels of inflammatory markers such as CRP were elevated by 1.8-fold in the complex-treated group (p<0.01), indicating a heightened inflammatory state.
Why It Matters
This research provides a critical link between innate immunity and lipoprotein metabolism in the context of atherosclerosis, highlighting LL-37-Apo B100 complexes as a novel pathogenic entity. The findings suggest that these complexes could serve as new biomarkers for assessing CAD risk or as potential therapeutic targets to mitigate disease progression. Understanding this interaction could pave the way for innovative diagnostic tools and interventions to prevent or treat cardiovascular disease. Future steps should include human observational studies to validate these complexes as clinical risk factors, followed by preclinical development of strategies to disrupt their formation or activity.