Polymorphic variant in gpx2 gene (rs4902346) and predisposition to type 2 diabetes mellitus

Oxidative stress is an important component of the pathogenesis of type 2 diabetes mellitus (T2D). Glutathione peroxidase 2 is one of the antioxidant defense enzymes which uses glutathione as a co-substrate to reduce hydrogen peroxide and has the highest expression in the pancreas, an organ that is directly related to the development of diabetes. However, there is no data on the association of GPX2 with a predisposition to T2D. The aim of the study was to investigate the association of rs4602346 (A>G) in the intron of the GPX2 gene with a risk of T2D, as well as the effect of this SNP on blood plasma redox homeostasis. The study included 3197 unrelated individuals of Slavic origin, including 1570 patients with T2D and 1609 age- and sex-matching healthy volunteers. GPX2 gene polymorphism was genotyped using real-time PCR on a CFX96 Touch Bio-Rad thermal cycler. The G/G genotype was associated with an increased risk of the disease (OR 1,41, 95% CI 1,02-1,96, P=0,039, recessive model). The identified association retained its significance even after correction for gender, age, and body mass index (ORadj 1,50, 95% CI 1,04-2,16, Padj=0,03). Gender-stratified analysis revealed that the established association of rs4902346 was characteristic only for diabetic males (ORadj 2,09, 95% CIadj 1,22-3,59, Padj=0,0065), and was not observed in diabetic females (P>0,05). Assessment of redox status showed an increase in the content of hydrogen peroxide and a decrease in the level of total glutathione in the plasma of patients compared with the control (P <0.05). A correlation analysis found that patients’ hydrogen peroxide levels are directly proportional to their fasting blood glucose concentrations. An analysis of the relationships between genetic and biochemical data showed that the G/G genotype rs4902346 is associated with a decrease in the content of reduced glutathione in the plasma of female patients with T2D (P=0,0086). Thus, we identified for the first time the association of rs4902346 with an increased risk of T2D and showed significant gender differences in the associations of the GPX2 gene with the studied phenotypes.

сахарный диабет 2-го типа, глутатион, глутатионпероксидаза, однонуклеотидный полиморфизм, наследственная предрасположенность, оксидантный стресс, type 2 diabetes mellitus, glutathione, glutathione peroxidase, single nucleotide polymorphism, genetic predisposition, oxidative stress