Abstract
To identify proteins related to the pathophysiology of aortic valve stenosis (AS), we investigated the protein profiles of AS aortic valves. Specifically, proteins were extracted from a thickened and calcified area (AS-C) and an apparently non-thickened and non-calcified area (AS-N) in an identical aortic valve leaflet in each of 6 AS patients. The proteins were then separated by 2-dimensional gel electrophoresis (2DE). Protein spots detected by 2DE were compared between the AS-C and AS-N samples. Protein spots of interest were subjected to protein identification by mass spectrometry.
In total, 670 protein spots were detected by 2DE, 28 of which showed more than 1.5-fold different intensity (P < 0.05) between the AS-C and AS-N samples. Proteins were identified in 17 out of the 28 spots. Fibrinogen and lumican were identified in 9 and 3 spots, respectively. Intensity of these 12 spots was lower in the AS-C samples than in the AS-N samples. In the 1D-Western blot analysis, 4 lumican bands (80 kDa, 75 kDa, 65 kDa, and 53 kDa) were detected, of which 2 bands with 80 kDa and 75 kDa showed lower intensity in the AS-C samples than in the AS-N samples. When de-glycosylated protein samples were used in the 1D-Western blot, only a single lumican band with ~40 kDa was detected, indicating that lumican was variously glycosylated and that highly glycosylated lumican molecules were decreased in AS-C.
Collectively, insufficient glycosylation of lumican in the thickened and calcified areas of AS aortic valves may be involved in the pathophysiology of AS.
