Objective: To investigate the association of the 482G/A polymorphism of the PGC-1alpha gene with type 2 diabetes by family-based study in the Han population in South China, and to analyze the quantitative and qualitative binding force changes between the PGC-1alpha domain mutant and MEF2C, as well as to evaluate the possibility of PGC-1alpha -MEF2C-GLUT4 pathway in the pathogenesis of type 2 diabetes.
Methods: Blood samples were collected from 350 patients with type 2 diabetes and their first-degree relatives. Genomic DNA was extracted and polymorphic PGC-1alpha genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism and direct DNA sequencing. The results were analyzed by family-based transmission disequilibrium test (TDT) and haplotype relative risk (HRR). The protein-protein interaction between PGC-1alpha and MEF2C was detected by means of the site-directed mutagenesis kit and bacteriomatch two-hybrid system kit.
Results: In the family-based study, HRR analyses demonstrated that the 482A allele was more often transmitted to patients than predicted by chance (chi (2)= 7.2170, P= 0.0072, HRR= 1.4496). TDT-extended test(ETDT) analyses also revealed that PGC-1alpha 482A allele was significantly deviated from 0.5 from heterozygous parents to patients than expected (219 trios, P= 0.0310; 350 trios, P= 0.0292). BacterioMatch Two-Hybrid System showed that 482A variation could lead to decreased binding force between PGC-1alpha and MEF2C (62.1+/- 8.97, P< 0.05).
Conclusion: The 482A polymorphism increases the risk of developing type 2 diabetic mellitus in the South China Han population, which might be mediated by the PGC-1alpha -MEF2C-GLUT4 pathway.