A Novel Mouse Model of Atherosclerotic Plaque Instability for Drug Testing and Mechanistic/Therapeutic Discoveries Using Gene and MicroRNA Expression Profiling

TLDR

Atherosclerosis causes high morbidity and mortality mainly through plaque rupture and thrombosis, yet animal models that mimic human plaque instability are scarce. The authors induced carotid plaque rupture in ApoE‑deficient mice using CFD‑guided tandem stenosis and profiled mRNA and miRNA to identify distinct gene and miR signatures linked to plaque instability. The model produced unstable plaques with hemorrhage, cap rupture, thrombosis, and neovascularization, and atorvastatin stabilized plaques while reducing MCP‑1 and ubiquitin; microarray analysis identified ADAMTS4 and miR‑322 as novel instability drivers confirmed in human plaques.

Abstract

The high morbidity/mortality of atherosclerosis is typically precipitated by plaque rupture and consequent thrombosis. However, research on underlying mechanisms and therapeutic approaches is limited by the lack of animal models that reproduce plaque instability observed in humans.Development and use of a mouse model of plaque rupture that reflects the end stage of human atherosclerosis.On the basis of flow measurements and computational fluid dynamics, we applied a tandem stenosis to the carotid artery of apolipoprotein E-deficient mice on high-fat diet. At 7 weeks postoperatively, we observed intraplaque hemorrhage in ≈50% of mice, as well as disruption of fibrous caps, intraluminal thrombosis, neovascularization, and further characteristics typically seen in human unstable plaques. Administration of atorvastatin was associated with plaque stabilization and downregulation of monocyte chemoattractant protein-1 and ubiquitin. Microarray profiling of mRNA and microRNA (miR) and, in particular, its combined analysis demonstrated major differences in the hierarchical clustering of genes and miRs among nonatherosclerotic arteries, stable, and unstable plaques and allows the identification of distinct genes/miRs, potentially representing novel therapeutic targets for plaque stabilization. The feasibility of the described animal model as a discovery tool was established in a pilot approach, identifying a disintegrin and metalloprotease with thrombospondin motifs 4 (ADAMTS4) and miR-322 as potential pathogenic factors of plaque instability in mice and validated in human plaques.The newly described mouse model reflects human atherosclerotic plaque instability and represents a discovery tool toward the development and testing of therapeutic strategies aimed at preventing plaque rupture. Distinctly expressed genes and miRs can be linked to plaque instability.