Protein Kinase C Deficiency Accelerates Neointimal Lesions of Mouse Injured Artery Involving Delayed Reendothelialization and Vasohibin-1 Accumulation

Objective—To use protein kinase C (PKC) –knockout mice to investigate the role of PKC in lesion development and to understand the underlying mechanism of the vascular disease. Methods and Results—PKC functions as a signal transducer mediating several essential functions of cell proliferation and apoptosis. However, the effect of PKC on neointimal formation in wire-injured vessels is unknown. Three weeks after wire injury of femoral arteries, neointimal lesions were significantly increased in PKC/ mice compared with PKC/ animals. Immunohistochemical staining revealed that total numbers of smooth muscle cells and macrophages in the lesions of PKC/ mice were markedly elevated without changing the ratio of these 2 cell types. To further elucidate the mechanisms of PKC-mediated increase in the lesion, an in vivo endothelial migration model was established to evaluate endothelial wound healing after wire injury. Data showed that reendothelialization of the injured vessel was markedly delayed in PKC/ mice; this coincided with more severe intimal hyperplasia. Migration of endothelial cells cultivated from cardiac tissue was markedly reduced in the absence of PKC, whereas no difference in proliferation or apoptosis was detected. Inhibition of PKC activity or protein expression by small hairpin RNA (shRNA) in cultured endothelial cells confirmed the defective migratory phenotype. Interestingly, vasohibin-1, an antiangiogenesis protein, was elevated in endothelial cells derived from PKC/ mice, which was mainly because of delayed protein degradation mediated by PKC. Downregulation of vasohibin-1 restored the migration rate of PKC