Interleukin-7 promotes monocyte/macrophage arrest on endothelial cells

ABSTRACT: Background: It is recognized that atherosclerosis can regresses at least in animal models. However, little is known about the mechanisms. We induced regression of advanced atherosclerosis in apolipoprotein E deficient (APOE­/­) mice and studied underlying mechanisms. Unexpectedly, our study led to the role of interleukin-7 (IL-7) in atherogenesis. Methods and Results: We treated APOE­/­ mice fed a high cholesterol diet for 30 weeks to induce advanced lesions with a helper-dependent adenoviral vector expressing human apoE3 (HDAd-gE3), and analyzed the regression of atherosclerosis after 41 weeks. Using microarray analysis, we identified IL-7 as one of most significantly affected genes by lowering cholesterol. To answer why IL-7 is downregulated by reduced cholesterol, we studied effects of IL-7 on endothelial cells (ECs). Our major findings were (1) long-term lowering cholesterol induced regression of advanced atherosclerosis. (2) Microarray analysis identified multiple signaling pathways affected by lowering cholesterol. (3) Correction for multiple testing revealed that IL-7 expression was downregulated, whereas gamma-sarcoglycan and α-actin were upregulated. (4) Oxidized LDL upregulated IL-7 expression in macrophages but not in aorta ECs or smooth muscle cells. (5) IL-7 increased the expression of cell adhesion molecules and chemokine in ECs and promoted monocyte adhesion to ECs. (6) Systemic elevation of IL-7 induced inflammatory response and recruited monocyte/macrophage to the lesions without increasing plasma cholesterol. Conclusion: Our finding suggest that IL-7 inflames endothelium and triggers the adhesion/recruitment of monocyte/macrophages to the atherosclerotic lesions and thus plays a direct role in development of atherosclerosis. Key Words: arteriosclerosis, gene therapy, hypercholesterolemia, interleukins, cell adhesion molecules

ORGANISM(S): Mus musculus

PROVIDER: GSE15914 | GEO | 2009/10/01

SECONDARY ACCESSION(S): PRJNA116913

REPOSITORIES: GEO