Peptidome profiling of umbilical cord plasma associated with gestational diabetes-induced fetal macrosomia.

Fetal macrosomia, defined as a birth weight ≥4000g, may affect 15-45% of newborns of women with gestational diabetes mellitus (GDM). The associations between endogenous peptides and gestational diabetes-induced macrosomia have not been investigated extensively by peptidome analysis. Here, we analyzed the umbilical cord plasma by combining ultrafiltration using molecular weight cut-off filters and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to investigate potential associations of GDM with macrosomia. As macrosomic babies have increased susceptibility to obesity, diabetes and cardiovascular diseases in later life, we also aimed to identify specific biomarkers to detect these future diseases. Thirty pairs of GDM mothers and controls were randomly divided into three subgroups. We identified 235 peptides of around 1000-3000Da, originating from 115 proteins. Analyzing the cleavage sites revealed that these peptides were cleaved in regulation, which may reflect the protease activity and distribution in umbilical cord plasma. Four identified peptides, of 2471.7, 1077.2, 1446.5 and 2372.7Da, were significantly differentially expressed in the GDM macrosomia groups compared with controls, whose precursors may play a critical role in developing GDM macrosomia. We provide for the first time a validated GDM macrosomia peptidome profile and identify potential biomarkers linking the effects of macrosomia to later-life diseases. BIOLOGICAL SIGNIFICANCE: Fetal macrosomia is the predominant adverse outcome of gestational diabetes mellitus (GDM), which is a frequent medical condition during pregnancy. Till now, the detailed molecular mechanisms underlying gestational diabetes-induced macrosomia are still not elucidated. With high detection sensitivity and high throughput of peptidome technology, it is now possible to systemically identify peptides possibly involved in the umbilical cord plasma of GDM induced macrosomia cases. With LC-MS/MS based quantification, totally, we identified 235 peptides originated from 115 precursor proteins. And four peptides of 2471.7, 1077.2, 1446.5 and 2372.7Da differentially expressed between GDM cases and compared controls. A precursor protein of 1077.2Da was fibrinogen alpha chain (FGA), which was also identified in the Ai et al. [29] study with a downregulated manner in the serum samples of GDM cases. And further analysis the cleavage pattern of the identified peptides revealed that the enzymes in tissues cleaved the protein according to their rules. Thus, this quantitative peptidome approach can identify related peptides that may play a role in the gestational diabetes-induced macrosomia, and give candidate biomarkers contributing to the development of later-life diseases in macrosomic babies.