Temporal and spatial localization of proteoglycan decorin transcripts during the progression of cholesterol-induced...

The temporal and spatial distribution of decorin transcripts, endothelial cells, and smooth muscle actin-producing cells were determined during the progression of atherosclerosis in the dorsal aortas of Japanese quail selected for cholesterol-induced atherosclerosis. The quail were placed on either a control diet or a diet containing 0.5% added cholesterol at approximately 16 weeks of age. Dorsal aortas were collected at 2-week intervals for 18 weeks after initiating cholesterol feeding. In situ hybridization for decorin showed the presence of decorin transcripts in the dorsal aorta intima of cholesterol-fed birds beginning at 6 weeks and continuing through the duration of the study. However, in the control-fed birds, decorin transcripts were not found in the intima but were prominent in the adventitia. In cholesterol-fed birds, immunohistochemical localization for endothelial cells showed that intima areas positive for decorin transcripts colocalized with both the endothelial cells and smooth muscle cell layers. In contrast in the control-fed birds, decorin transcripts aligned with the smooth muscle cell layers and not the endothelial cells. These results are suggestive of a potential role for endothelial cells in intimal decorin expression during atherosclerotic plaque formation.