DNA methylation of tumor necrosis factor-α, monocyte chemoattractant protein-1, and adiponectin genes in visceral adipose tissue is related to type 2 diabetes in the Xinjiang Uygur population

BackgroundThe higher probability of type 2 diabetes mellitus (T2DM) in the Uygur population is due to a greater waist:hip ratio and visceral fat. This study investigated DNA methylation of tumor necrosis factor- (TNF), monocyte chemoattractant protein-1 (MCP1), and adiponectin (ADIPOQ) in visceral adipose tissue in T2DM. MethodsVisceral adipose tissue was collected from Uygur individuals and divided into normal control (NC; n=50), obese (Ob; n=48), and T2DM (n=26) groups. Expression of TNF, ADIPOQ, and MCP1 mRNA and DNA methylation status were quantified by reverse transcription-polymerase chain reaction and denaturing HPLC. ResultsThe respective methylation-positive rate for ADIPOQ increased gradually from the NC to Ob to T2DM groups (34.0%, 47.9%, and 65.4%; P<0.05), decreased gradually for TNF (70.0%, 47.9%, and 26.9%; P<0.01), and did not differ significantly for MCP1 (0%, 2.08%, and 0%). Compared with the NC group, ADIPOQ mRNA expression was significantly lower in the Ob and T2DM groups (median 0.7162 vs 0.4244 and 0.4093, respectively; P<0.05), whereas TNF and MCP1 expression was significantly higher (median TNF expression: 0.0250 vs 0.1096 and 0.0734 respectively; median MCP1 expression 0.1588 vs 0.1937 and 0.1983, respectively; P<0.05 for all). Expression of ADIPOQ and TNF was significantly lower in methylation-negative (median 0.7870 and 0.1988, respectively) than methylation-positive (median 0.2700 and 0.0542, respectively) groups (P<0.01). ConclusionsLower ADIPOQ and higher TNF and MCP1 mRNA expression in visceral adipose tissue may be correlated with obesity and T2DM in the Uygur population. Promoter DNA methylation affects expression of ADIPOQ and TNF.