Comparative Proteomic Analysis of Gallbladder Bile Proteins Related to Cholesterol Gallstones

BACKGROUND: Nucleation of cholesterol monohydrate crystals following the aggregation and fusion of cholesterol-enriched vesicles is a critical procedure in the formation of cholesterol gallstone. Biliary proteins play important roles in the process. It is inefficient to screen pro-nucleating or anti-nucleating proteins with routine physiochemical techniques, by which we discovered several pro-nucleating proteins. METHODOLOGY/PRINCIPAL FINDINGS: Based on comparative proteomic technologies, we investigated the differentially expressed proteins between the cholesterol gallstone and control groups, and between the vesicular phase and micellar phase. There are 401±75 spots detected on the cholesterol gallstone group and 389±94 spots on the control group gels, 120±24 spots detected on vesicular phase and 198±37 on micellar phase gels, and accordingly 22 and 8 differentially expressed proteins were identified successfully, respectively. Three of them, HSA, Profilin and Retinol Binding Protein, were validated by Western blot. CONCLUSION/SIGNIFICANCE: Some of the identified proteins are in good agreement with proteins reported to be involved in the gallstone formation before. The information from this study might provide some important clues to uncover the key proteins involved in the formation of cholesterol gallstone.