Proteomic analysis of a podocyte vesicle-enriched fraction from human normal and pathological urine samples.

Podocytes (glomerular visceral epithelial cells) release vesicles into urine. Podocyte vesicle-enriched fractions from normal and pathological human urine samples were prepared for proteomic analysis. An immunoadsorption method was applied and enrichment of podocyte vesicles was assessed. We identified 76 unique proteins. One protein, serum paraoxonase/arylesterase 1 (PON-1), was newly identified in normal human urine sample. We confirmed this result and showed PON-1 expression in normal human kidney. These results demonstrated the potential for using the urine samples enriched in podocyte vesicles as a starting material in studies aimed at discovery of biomarkers for diseases.