Stearoyl-CoA desaturase regulates inflammatory gene expression by changing DNA methylation level in 3T3 adipocytes

Adipocytes are one of the primary sources of inflammatory cytokines that drive the low-grade inflammation associated with obesity and obesity-related diseases. Stearoyl-CoA desaturase, a key adipogenic enzyme in rodents and humans, plays significant role in the regulation of adipocyte inflammation via a mechanism that involves the regulation of inflammatory gene expression. In the present study, we tested the hypothesis that the stearoyl-CoA desaturase 1-related regulation of gene expression might be driven by changes in DNA methylation. We showed that stearoyl-CoA desaturase 1 overexpression causes the global hypomethylation of DNA, even as early as 12h after the induction of differentiation, with the greatest difference seen in mature adipocytes. In contrast, both the silencing of stearoyl-CoA desaturase 1 gene expression by siRNA and inhibition of stearoyl-CoA desaturase 1 activity resulted in DNA hypermethylation in 3T3-L1 adipocytes. The analysis of the promoter methylation of 22 genes that are related to the inflammatory response showed that the level of methylation of CpG sites in interleukin-10 receptor a, interleukin-4 receptor a, interleukin-6 signal transducer, and transforming growth factor β 1 promoters was strongly related to stearoyl-CoA desaturase 1 expression or activity. The changes in methylation at CpG promoter sites correlated with differential expression of the aforementioned genes. The results show that stearoyl-CoA desaturase 1 regulates the level of DNA methylation in adipocytes and suggest that the mechanism by which stearoyl-CoA desaturase 1 affects adipocyte inflammation may involve changes in the methylation of inflammatory genes.