Participant characteristics
A case-control study was conducted on a total of 1122 women (267 GDMs and 855 controls) who had spontaneous deliveries at the University of Malaya Medical Center (UMMC) from April 2014 to June 2016. All participants were characterized by pregnancy, were nonsmokers, and did not abuse alcohol. The selection criteria for the study were the age of the mother between the ages of 18 and 45 and the diagnosis of gestational diabetes by a trained doctor. The age of mothers between the ages of 18 and 45 with normal pregnancies served as a control. Abnormal fetal, still giving birth, sickle cell anemia, thalassemia or other hemoglobinosis, and other pregnancies such as lupus, hypertension, thyroid disease, cardiovascular disease, transplantation, kidney disease, asthma or other serious disease Women diagnosed with previous conditions, drug abuse, a history of smoking and depression, and carriers of blood-borne infections were excluded. Screening was performed between the 24th and 28th weeks of gestation using the Modified Oral Glucose Tolerance Test (mOGTT). Universal screening includes pregnant women with a BMI greater than 27 kg / m2, previous giants weighing 4 kg or more, previous GDM, one-time relatives with diabetes, a history of unexpected prenatal fetal death, and birth defects. It was performed on pregnant women with a medical history Positive. GDM is defined as fasting plasma glucose (FPG) (≥5.1) and 75 g mOGTT plasma glucose (≥7.8). Substantial risk women with normal initial screening results were subjected to a repeat mOGTT at 4–6 weeks later. The control consisted of uncomplicated pregnant mothers who gave birth to a baby between 38 and 41 weeks. Trained personnel assessed the physical health of the mother and gestational age was calculated from the first day of the last menstrual cycle or from the patient's early ultrasound scan results.
Serum RNAs extraction and cDNA synthesis
Twenty-four women with GDM were included. Maternal samples were collected within first, second, third trimesters and 2-6 months postpartum. Twenty-four healthy pregnant women served as controls. Total RNAs were extracted from serum samples using the miRNeasy serum/plasma kit and synthesized into cDNA using the miScript II Rt kit according to the manufactures protocol (Qiagen, Mississauga, Ontario, Canada).
MiRNAs expression profiling
A pathway-focused miScript miRNA PCR Array Human Diabetes (Qiagen, Mississauga, Ontario, Canada) was used in combination with miScript SYBR Green PCR kit (Qiagen) to profile miRNA expression in a 96-well plate using a Step One Plus™ real time PCR detection system (Applied Biosystem, California, USA) following the cycling conditions recommended by the manufacturer’s instructions. Amplification conditions were 15 min at 95∘C, followed by 40 cycles of 15s at 94∘C, 30s at 55∘C, and 30s at 70∘C. A total of 37 miRNAs involved in GDM phenotype were selected for the PCR array. Six snoRNA/snRNA, including SNORD61, SNORD68, SNORD72, SNORD95, and SNORD96A were selected as housekeeping genes. Furthermore, miRTC and PPC genes served as reverse transcription control and primer assay positive control, respectively. PCR array reactions were conducted in triplicate repeats. The data were analyzed using online Gene Globe data analysis software version 2.1.0 (https://geneglobe.qiagen.com/). The validity and accuracy of array PCR were confirmed using reverse transcription-qPCR for five randomly selected miRNAs in triplicate.
ROC curve analysis
A receiver operating characteristic (ROC) which is a plot of the true positive rate (Sensitivity) in function of the false positive rate (100-Specificity) for different cut-off points of a parameter was performed to evaluate the potential microRNAs biomarker characteristics.
Insilico Target Genes Identification and Bioinformatic Analysis
Target Scan Human Release 8.031 and miRDB 32 were used to obtain predicted or previously experimentally validated miRNA target genes. Interaction network analysis was performed using the Cytoscape 3.7.1 tool to verify all potential interactions between the identified target gene and potential functional mediators.