N-Glycosylation Pattern of Human Placental Insulin-Like Growth Factor and Insulin Receptors in Well-Controlled Pregestational Diabetes Mellitus

Diabetes mellitus is a complex disease that leads to alterations in the glycosylation of proteins. Insulin-like growth factor and insulin receptors are involved in the regulation of fetal and placental growth and development. In this work the N-glycans of these receptors, originating from placentas obtained from pregnancies complicated by pregestational insulin dependent diabetes mellitus, were studied. Diabetic mothers were under regular insulin therapy. Solubilised membrane samples from healthy and diabetic placentas were analysed using lectin-affinity chromatography. N-glycans bound to insulin-like growth factor and insulin receptors were studied in terms of their interaction with eleven agarose-immobilised lectins: wheat germ agglutinin, succinylated wheat germ agglutinin, Ricinus communis agglutinin I, Sambucus nigra agglutinin, Erythrina cristagalli lectin, Ulex europaeus agglutinin, Lens culinaris agglutinin, Canavalia ensiformis lectin, Phaseolus vulgaris erythro- and leukoagglutinin and Maackia amurensis agglutinin. A very similar type of N-glycans and content of the terminal saccharide residues were found in both groups of placentas. The results of this work suggest that the tight glycemic control may prevent alterations in the glycosylation of insulin-like growth factor and insulin receptors, thus maintaining physiological homeostasis during pregnancy and fetal growth.