Screening of serum biomarkers of preeclampsia by proteomics combination with bioinformatics

Objective: To screen for novel predictive serum markers of preeclampsia (PE). Method: Blood samples were collected from seven women with PE and five with healthy pregnancies. Serum proteins were identified using isobaric tags for relative and absolute quantitation (iTRAQ) technology combined with liquid chromatography mass spectrometry analysis. The differentially expressed proteins in the PE samples were identified using the SwissProt database, and functionally annotated by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. The upregulated proteins from iTRAQ result were verified by ELISA. Results: We identified 121 differentially expressed proteins, of which 76 were upregulated and 45 were downregulated, and 14 were differentially expressed by more than two-folds. The top GO terms for Cellular Components (CC) were high-density lipoprotein particles and plasma lipoprotein particles, defense response for Biological Processes (BP), and glycosaminoglycan binding, heparin binding and sulfur compound for Molecular functions (MF). The pathway hsa04979 for Cholesterol metabolism was significantly enriched among the upregulated proteins, while the structural domain was enriched in immunoglobulin subtype 2. The dysregulation of pregnancy-specific beta-1-glycoprotein 2 (PSG2) was confirmed by ELISA. Conclusion: PE pathogenesis is related to lipid metabolism and inflammation, and proteins related to these pathways are potential early diagnostic markers for PE.PSG2 may be a marker of PE.