Investigating Placental EFA metabolism in GDM through Integrative spatial multiomics

The prevalence of gestational diabetes (GDM) is increasing in association with more adverse pregnancy outcomes and greater risk of development of type 2 diabetes in later life. GDM is associated with many fetal and newborn complications and programming of offspring for development of obesity and diabetes. A male fetus is at greater risk of adverse outcome than a female fetus perhaps related to the sexual dimorphism in placental gene expression, placental inflammatory, hypoxia and apoptotic responses, antioxidant defenses, miRNA expression and mitochondrial dysfunction. Placental mitochondria are the main source of ATP required to power peptide hormone production, nutrient uptake and transfer and are central to generation of oxidative stress and inflammatory responses. Placental mitochondrial respiration is reduced with the hyperglycemia, hyperinsulinemia and hyperlipidemia of obesity and GDM together with altered fuel flexibility where male but not female trophopblast lose flexibility to switch between use of glucose, fatty acids and glutamine. Lipidomic analysis showed male but not female placentae from GDM had a significantly lower proportion of docosahexaenoic acid (DHA)-containing triglycerides (storage lipids) vs lean or obese placenta. DHA is an essential fatty acid crucial for fetal brain development but also important for membrane structure/function, reducing oxidative stress and inflammation and regulating mitochondrial function, hence there is a need to define DHA actions in the male vs female placenta and if these are affected with obesity and GDM. Using proteomic analysis, GDM male placentae showed significant downregulation vs lean male placentae of pathways related to protein synthesis and upregulation of inflammatory pathways. In contrast female GDM placentae showed downregulation, vs lean and obese, of pathways related to glucose metabolism. Hence, we have a strong premise to determine the mechanisms underlying the sexual dimorphism of cellular response to the GDM milieu in placenta and particularly if DHA has a central role in this. Our previous `omic' work was on whole placental villous tissue, obscuring the spatial localization of signals. We have developed a metabolome-informed proteome imaging (MIPI) workflow where MALDI-MSI allows multi-modal imaging of 12μm placental villous tissue sections, showing regions of differing metabolic activity and complementary proteome profiling of mapped regions captures region-specific enzymes and highlights functional differences between syncytiotrophoblast and villous core compartments. We will employ the MIPI technology on tissue sections and also employ trophoblast cultures of male and female placentas of lean and obese women each with or without type A2GDM pregnancies to test the hypothesis that there is sexual dimorphism in the setting of maternal obesity and GDM in cellular pathways and mechanisms involving trophoblast mitochondrial function, protein homoeostasis, oxidative stress, inflammation and insulin resistance regulated by the essential fatty acid DHA, This technically and conceptually innovative work may lead to establishment of fetal sex-specific therapeutic approaches in such pregnancies.