Roles of differentially expressed proteins in maternal sera of neural tube defect fetuses

Abstract

Objective To determine whether the profiling of maternal sera proteins in neural tube defects (NTDs) pregnancy is different from that of normal pregnancy controls using label-free quantitation. Methods Ten pregnant women whose fetuses were diagnosed ultrasonically with NTDs and consisting of spina bifida (n=5), anencephaly (n=2) and encephalocele (n=3) were selected along with another 10 pregnant women with normal fetuses.Samples of 5 ml peripheral venous blood of all pregnant women were harvested early in the morning.The sera samples were collected and purified by centrifugation.Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), the proteins were extracted, digested by filter-aided sample prep (FASP) and followed by extraction of peptides and desalination.The proteins were then identified by label-free quantitative analysis plus LC/MS/MS-based proteomics.The differentially expressed proteins involved in biological functions were analyzed using protein bioinformatics analysis plus Unipart Database, including Gene Ontology, signaling pathways and protein interactions. Results Significant inter-group differences existed in 17 protein peaks.Among 17 proteins, 12 were up-regulated proteins/peptides, including pregnancy zone protein, complement C1q subcomponent subunit A, B & C, human cDNA FLJ51564, FLJ56954 & FLJ78071, hemoglobin subunit alpha & beta, carbonic anhydrase 1, keratin, type II cytoskeletal 80 and peroxiredoxin-2; 5 were down-regulated proteins/peptides, including pappalysin-1, protein S100A9, serotransferrin, human cDNA FLJ61165 and FLJ53691.The above-mentioned proteins were involved in biological regulation, signal transduction, cellular processes, cell growth, cell adhesion, cellular components, transporter activities, catalysis activities and metabolic processes. Conclusions There are differential expression profiles of serum proteins between neural tube defect group and control group using label-free quantitation. Key words: Neural tube defects; Serum; Pregnant women; Computational biology