Gestational diabetic transcriptomic profiling of microdissected human trophoblast

Abstract

Gestational diabetes mellitus (GDM), the most common metabolic complication of pregnancy, is influenced by the placenta, and its prevalence directly increases with obesity. Therefore, to define the aetiology of GDM requires that the confounding influence of obesity and the heterogeneous nature of the placenta impairing accurate quantitative studies be accounted for. Using laser capture microdissection (LCM), we optimized RNA extraction from human placental trophoblast, the metabolic cellular interface between mother and foetus. This allowed specific transcriptomic profiling of trophoblast isolated from GDM, and obese and normal human placentae. Genome-wide gene expression analysis was performed on the RNA extracted from the trophoblast of GDM and obese and normal placentae. Forty-five differentially expressed genes (DEGs) specifically discriminated GDM from matched obese subjects. Two genes previously linked with GDM, pregnancy specific beta-1 glycoprotein 6 (PSG6) and placental system A sodium-dependent transporter system (SLC38A1), were significantly increased in GDM. A number of these DEGs (8 ubiquitin-conjugating enzymes (UBE) splice variants (UBE2D3 variants 1, 3, 4, 5, 6, 7, and 9) and UBE2V1 variant 4)) were involved in RNA processing and splicing, and a significant number of the DEGs, including the UBE variants, were associated with increased maternal fasting plasma glucose. It is concluded that DEGs discriminating GDM from obese subjects were pinpointed. Our data indicate a biological link between genes involved in RNA processing and splicing, ubiquitination, and fasting plasma glucose in GDM taking into account obesity as the confounder.

Diabetes in Pregnancy and MicroRNAs: Promises and Limitations in Their Clinical Application

“…A small study assessing placental gene expression (using a metabolic gene array) in women with type 1 diabetes, obese women with gestational diabetes and women without diabetes, showed differential regulation of lipid-metabolism related genes in the women with gestational diabetes [46]. More recent studies have tried to discriminate the effects on gene expression caused by gestational diabetes itself and those associated with obesity, revealing upregulation in gestational diabetes of genes involved in RNA processing and splicing [47], as well as divergent expression of genes such as mTOR and AMPK [48]. Placental miRNA expression in gestational and pre-gestational diabetes is reviewed in Section 2.3 and Section 2.4.…”

miR-876-3p regulates glucose homeostasis and insulin sensitivity by targeting adiponectin

“…miR876 has been found to be elevated in type 1 diabetes patient (Satake et al 2018). It has also been showed that miR876-5p is elevated in human trophoblast during gestational diabetes (Bari et al 2016). However, from these studies, it will be premature to conclude the role of miR-876 in diabetes.…”

Current approaches and developments in transcript profiling of the human placenta

“…2 ). For instance, studies addressing invasion of the extravillous trophoblast into the maternal decidua sample the basal plate ( Winn et al , 2009 ), while those investigating the maternal–foetal transfer across the syncytiotrophoblast would sample the villous placenta ( Bari et al , 2016 ). Unwanted variation may arise from inappropriate sampling of the placenta, such as non-removal of the decidua for studies of the villous placenta, inclusion of infarcted areas and insufficient cleaning to remove excess blood.…”

“…Studies have also considered other forms of diabetes in pregnancy, such as pre-existing type I and type II diabetes ( Radaelli et al , 2009 ; Alexander et al , 2018 ) or tried to account for differences in maternal obesity, which is more common in diabetic groups compared with controls ( Bari et al , 2016 ). However, as the numbers of each diabetic type or BMI group are small, more studies are needed to confirm if the identified differences are due to diabetes or obesity.…”