Modulation of cysteine-rich protein 2 expression in vascular injury and atherosclerosis

Vascular smooth muscle cells (VSMCs) of the arterial wall normally display a differentiated and contractile phenotype. In response to arterial injury, VSMCs switch to a synthetic phenotype, contributing to vascular remodeling. Cysteine-rich protein 2 (CRP2) is a cytoskeletal protein expressed in VSMCs and blunts VSMC migration in part by sequestering the scaffolding protein p130Cas at focal adhesions. CRP2 deficiency in mice increases neointima formation following arterial injury. The goal of this study was to use Csrp2 promoter-lacZ transgenic mice to analyze CRP2 expression during VSMC phenotypic modulation. In a neointima formation model after carotid artery cessation of blood flow, lacZ reporter activity and smooth muscle (SM) alpha-actin expression in the media were rapidly downregulated 4 days after carotid ligation. Fourteen days after ligation, there was a high level expression of both Csrp2 promoter activity and SM a-actin protein expression in neointimal cells. In atherosclerosis prone mice fed an atherogenic diet, Csrp2 promoter activity was detected within complex atherosclerotic lesions. Interestingly, Csrp2 promoter activity was also present in the fibrous caps of complicated atherosclerotic lesions, indicating that CRP2 might contribute to plaque stability. These findings support the concept that CRP2 contributes to the phenotypic modulation of VSMCs during vascular disease. Modulating transcription to increase CRP2 expression during vascular injury might attenuate vascular remodeling. In addition, increased CRP2 expression at the fibrous caps of advanced lesions might also serve to protect atherosclerotic plaques from rupture.