Proteome differences of placenta between pre-eclampsia and normal pregnancy

Placenta is a tissue unique to pregnancy and despite its major role in pregnancy, little is known about the proteome changes within placenta during pregnancy-related diseases such as pre-eclampsia (PE). Therefore, the aim of this study is the analysis of proteome differences between pre-eclamptic and normal full-term placentas. To achieve this goal, five normal and five severe pre-eclamptic placentas were included in this study. Total placental proteins were extracted and subjected to two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). After staining, the gels were scanned and the protein spots were analysed using Image Master 2D Platinum Software. Non-parametric Mann-Whitney test was used for analysis of the mean intensity differences of the spots between normal and pre-eclamptic placentas. Statistical analysis indicated that 17 spots were differently expressed in pre-eclamptic compared with normal placentas (p<0.05). Using Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI TOF/TOF) mass analysis, 11 out of 17 spots were identified. Among them, four proteins (chloride intracellular channel 3, apolipoprotein A-I, transthyretin (TTR) and protein disulphide isomerase) were up-regulated while seven (peroxiredoxin 2, peroxiredoxin 3, Hsc 70, Cu/Zn-superoxide dismutase (SOD-1), actin gamma 1 propeptide, chain A of enoyl-coenzyme A hydratase and HSP gp96) showed decreased expression in PE in comparison with normal placentas. In conclusion, down-regulation of proteins with anti-oxidant activities (peroxiredoxin 2 and peroxiredoxin 3) and altered expression of stress-response proteins (Hsc 70, Hsp gp96 and protein disulphide isomerase) might play an important role in the pathogenesis of PE.