Apolipoprotein C3 Promotes Angiogenesis in an Inflammatory Mouse Model of Peripheral Artery Disease

Abstract

Apolipoprotein C3 (ApoC3) regulates triglyceride metabolism and is associated with accelerated atherogenesis and adverse cardiovascular outcomes. However, its role in peripheral artery disease (PAD) remains unclear. We investigated whether Apoc3 deficiency impacts key features of PAD. Vascularization was assessed using an inflammatory periarterial cuff model (21 days) and a hind limb ischemia model (14 days) in male and female Apoc3+/+ and Apoc3−/− mice. Neovascularization was also assessed in mice following extracellular matrix (ECM) plug implantation. Isolated human umbilical vein endothelial cells (HUVECs) were co-cultured with ApoC3-stimulated THP-1 monocytes, and tubule formation was assessed. Apoc3-deficient mice demonstrated less neovessel formation around the cuffed femoral artery, with endothelial cell (CD31+) staining reduced by approximately 40% compared to Apoc3+/+ mice. Twenty-four hours after cuff placement, Apoc3+/+ vessels exhibited increased expression of angiogenic (Hif1a and Vegf1) and pro-inflammatory (Cd68) markers, while Apoc3-deficient vessels did not. Confirming a role for inflammation in ApoC3-induced angiogenesis, tubulogenesis of HUVECs increased only in the presence of ApoC3 and THP-1 monocytes. Apoc3 deficiency, however, did not affect ischemia-driven angiogenesis, as there were no differences in revascularization compared to Apoc3+/+ mice, as assessed by the perfusion index (laser Doppler), fibrosis (Picrosirius red staining), or the mRNA expression of apoptotic (Bax), angiogenic (Hif1a and Vegf1), and inflammatory (Ccl2, Il6, and Vcam1) markers in the ischemic hind limb. Neovascularization following ECM plug implantation was also unaffected by Apoc3 deficiency. In conclusion, ApoC3 contributes to pathological, inflammation-driven angiogenesis, highlighting its potential as a therapeutic target for pathological angiogenesis without inhibiting physiological ischemia-driven angiogenesis.