A proteomic view on the role of glucose in peritoneal dialysis

Peritoneal dialysis is a frequently used mode of renal replacement therapy although peritoneal dialysis fluid (PDF) acts as stressor for mesothelial cells. In this study, stress response to PDF is investigated by a proteomics approach using Met-5A cell cultures closely resembling mesothelial cells. In a previous work, we identified about 100 proteins as significantly enhanced or diminished in abundance after full-PDF stress (90 mM glucose, pH 5.8, and presence of lactate and glucose degradation products (GDPs)) using two-dimensional electrophoresis (2-DE) and MALDI-MS and MS/MS techniques. In this paper, a functional analysis is presented assigning these proteins to glucose associated pathways according to the KEGG database. To establish the stressor role of high glucose concentration, the up/down regulation of proteins populating these pathways were investigated in a fluorescence-difference gel electrophoresis (DIGE) experiment exposing Met-5A cells to nonphysiologically high glucose conditions only. In this glucose-single stress experiment, the fold-change ratios of the investigated glucose-pathway associated proteins were found much lower than observed in the previous full-PDF stress experiments. This finding supports the hypothesis that cellular response to full-PDF stress is not primarily induced by the high glucose concentration, even when focusing on proteins belonging to the glucose associated pathways.