ABSTRACT
Objective: To explore the effect of glucose on Akt2 gene methylation and mRNA level in the trophoblast cell line HTR8/SVneo and the association between first-trimester Akt2 mRNA level in peripheral blood and pre-pregnancy body mass index (BMI) and gestational diabetes mellitus (GDM). Methods: The cell model of intrauterine hyperglycemia in pregnant women with GDM was established, and divided into 5 groups based on the different glucose concentrations (2.5, 5.0, 10.0, 25.0, and 40.0 mmol/L). The mRNA levels of Akt2 gene were detected by real-time quantitative PCR, and the methylation levels of Akt2 gene promoter region were detected by mass spectrometry. According to pre-pregnancy BMI and diagnosis of GDM, 60 pregnant women who had given birth at Peking University First Hospital during December 2014 to July 2016 were classified into overweight non-GDM group, overweight GDM group, obese non-GDM group and obese GDM group. Real-time quantitative PCR analyses were used to detect the levels of Akt2 mRNA in first-trimester peripheral blood of the 4 groups. Results: (1) Level of Akt2 mRNA significantly rose with the glucose concentration of medium increased, showing concentration dependency (all P<0.05). Compared with the 25.0 mmol/L group, the following methylation levels changed significantly (all P<0.05): cytosine-phosphate-guanine (CpG) 10, CpG23, and CpG24.5 of Akt2 gene promoter region in the 5.0 mmol/L group, CpG23 and CpG24.5 in the 2.5 mmol/L group, and CpG10 in the 10.0 mmol/L group. Compared with the 5.0 mmol/L group, CpG10 in the 40.0 mmol/L group showed methylation change (P<0.05). (2) Compared with the overweight non-GDM group [1.04(0.90~1.26)], overweight GDM group [2.10(1.85~2.28)] and obese GDM group [1.68(0.82~2.43)] all had higher Akt2 mRNA levels and the differences were statistically significant (all P<0.05). Compared to obese GDM group [1.68(0.82~2.43)], the level of Akt2 mRNA was higher in overweight GDM group [2.10(1.85~2.28)] and lower in obese non-GDM group [1.00(0.71~2.17)], but the differences were not statistically significant (all P>0.05). Conclusions: Glucose might affect Akt2 mRNA level by changing the methylation of Akt2 gene promoter region, and the change might appear in the first trimester of pregnant women with GDM, especially for women with lower pre-pregnancy BMI.
