A proteome signature for intrauterine growth restriction derived from multifactorial analysis of mass spectrometry‐based cord blood serum profiling

Abstract

Intrauterine growth restriction (IUGR) is defined as a condition in which the fetus does not reach its genetically given growth potential, resulting in low birth weight. IUGR is an important cause of perinatal morbidity and mortality, thus contributing substantially to medically indicated preterm birth in order to prevent fetal death. We subjected umbilical cord blood serum samples either belonging to the IUGR group (n = 15) or to the control group (n = 15) to fractionation by affinity chromatography using a bead system with hydrophobic interaction capabilities. So prepared protein mixtures were analyzed by MALDI-TOF mass spectrometric profiling. The six best differentiating ion signals at m/z 8205, m/z 8766, m/z 13 945, m/z 15 129, m/z 15 308, and m/z 16 001 were collectively assigned as IUGR proteome signature. Separation confidence of our IUGR proteome signature reached a sensitivity of 0.87 and a specificity of 0.93. Assignment of ion signals in the mass spectra to specific proteins was substantiated by SDS-PAGE in conjunction with peptide mass fingerprint analysis of cord blood serum proteins. One constituent of this proteome signature, apolipoprotein C-III(0) , a derivative lacking glycosylation, has been found more abundant in the IUGR cord blood serum samples, irrespective of gestational age. Hence, we suggest apolipoprotein C-III(0) as potential key-marker of the here proposed IUGR proteome signature, as it is a very low-density lipoprotein (VLDL) and high-density lipoprotein (HDL) member and as such involved in triglyceride metabolism that itself is discussed as being of importance in IUGR pathogenesis. Our results indicate that subtle alterations in protein glycosylation need to be considered for improving our understanding of the pathomechanisms in IUGR.

Alterations of protein expression in serum of infants with intrauterine growth restriction and different gestational ages

“…Subsequently, these authors reported that MS profiling is confirmatory to clinical surveillance with the potential to identify neonates with IUGR postnatally [27]. As far as we know, the present study is the first to assess the changes in serum proteome of IUGR neonates stratified by their GA, in venous blood samples drawn at 1, 7 and 30 days after birth, not in umbilical cord blood as previously made in previous studies in human neonates [24][25][26][27]. Sera from each GA group were pooled, so that each neonate contributed an equal amount of protein to the mixture before 2-DE analysis.…”

“…Cord blood alterations toward an atherogenic phenotype were assumed to underlay the predisposition of IUGRs for cardiovascular diseases [34]. Thus, in umbilical cord blood sera of 15 IUGR and 15 AGA, the six best ion signals obtained by MALDI-TOF profiling were considered to represent the IUGR proteome signature, also suggesting apolipoprotein C-III 0 as a potential key marker [26]. Since they focused on the atherogenic phenotype secondary to IUGR, a Protein Profiling Kit MB-HIC8 (Bruker) based on hydrophobic interactions was used to enrich the serum proteins from umbilical cord blood.…”

“…Since they focused on the atherogenic phenotype secondary to IUGR, a Protein Profiling Kit MB-HIC8 (Bruker) based on hydrophobic interactions was used to enrich the serum proteins from umbilical cord blood. In consequence, most proteins identified were lipoprotein components and transporters, and major blood proteins, as several hemoglobin chains, were also included [26]. Subsequently, these authors reported that MS profiling is confirmatory to clinical surveillance with the potential to identify neonates with IUGR postnatally [27].…”

“…Sample pooling has become a common practice in Proteomics, because the analysis of pooled samples helps to reduce the number of replicates required and the standard deviation obtained from individual samples [35]. To focus on minority serum proteins and to avoid any bias toward lipoproteins [26,27,34], the abundant serum proteins were depleted using the ProteoMiner TM kit (Bio-Rad®), which depletes high-abundance proteins via binding to a highly diverse bead-based library of combinatorial peptides while enriching those of medium-and low-abundance, without using immunodepletion.…”

“…Later, Ceconi et al reported protein alterations in IUGR umbilical cord serum and amniotic fluid [25], affecting proteins involved in coagulation, the immune response, blood pressure and iron and copper homeostasis. In umbilical cord blood sera of 15 IUGR and 15 AGA newborns fractionated by hydrophobic interactions, the six best differentiating ion signals obtained by MALDI-TOF profiling were assigned as IUGR proteome signature, proposing apolipoprotein C-III 0 as potential key marker [26]. Mass spectrometric profiling is confirmatory to clinical surveillance with the potential to identify neonates with IUGR postnatally [27].…”