Expression profiling identifies 147 genes contributing to a unique primate neointimal smooth muscle cell phenotype

Area of Science:

• Vascular biology
• Molecular genetics
• Cardiovascular research

Background:

• Intimal hyperplasia is a significant factor in vascular graft failure.
• Understanding the molecular mechanisms of neointimal formation is crucial for developing effective treatments.

Purpose of the Study:

• To systematically characterize gene expression differences in neointima using expression array analysis.
• To identify novel genes associated with smooth muscle cell (SMC) behavior in neointimal hyperplasia.

Main Methods:

• Comparison of gene expression profiles of smooth muscle cells (SMCs) from neointima, normal aorta, and vena cava in cynomolgus monkeys.
• Utilized cDNA arrays for high-throughput gene expression analysis.
• Validated array findings using Northern analysis, in situ hybridization, and immunohistochemistry.

Main Results:

• Identified 147 differentially expressed genes between neointima and aorta SMCs, with a predominant suppression pattern.
• Discovered 13 induced genes in neointima, including matrix proteins and inducers of matrix synthesis (e.g., osteoblast-specific factor-2/Cbfa1).
• Found 45 differentially expressed genes between neointima and vena cava SMCs, with most being induced.

Conclusions:

• Matrix synthesis plays a critical role in neointimal maturation.
• Novel genes, including regulator of G-protein signaling-5 and osteoblast-specific factor-2/Cbfa1, are newly associated with neointimal SMCs.
• These findings generate new hypotheses regarding the pathogenesis of intimal hyperplasia.