Low-level perfluorooctanoic acid enhances 3 T3-L1 preadipocyte differentiation via altering peroxisome proliferator activated receptor gamma expression and its promoter DNA methylation.

Recent studies suggest that perfluorooctanoic acid (PFOA) can play a role in the development of obesity; however, the associated mechanisms are poorly understood. We investigated how PFOA exposure affected the differentiation of 3 T3-L1 preadipocytes and the associated transcriptional and epigenetic mechanisms. Cells treated with different doses of PFOA (ranging from 0.01 to 100 μg ml ) were assessed for proliferation, differentiation and triglyceride accumulation. The gene expression levels of peroxisome proliferator activated receptor gamma (PPARγ) and its target genes were measured. DNA methylation levels of PPARγ promoter and global DNA methylation levels were also tested. We found a concentration-dependent enhancement of adipocyte proliferation and differentiation following PFOA exposure. PFOA also induced a significant concentration-dependent increase in the accumulation of lipid and triglyceride. Increased gene expression was also observed for PPARγ, CCAAT/enhancer binding proteins α, fatty acid binding protein 2 and lipoprotein lipase in differentiated cells after PFOA exposure. The ability of PFOA to induce adipogenesis was blocked by GW9662, a known PPARγ antagonist. In addition, significant demethylation of the cytosine-phosphate-guanine sites in the PPARγ promoter was observed after exposure to PFOA. In addition, PFOA exposure resulted in decreased global DNA methylation and increased expression levels of DNA methyltransferases genes. We found that treatment with low levels of PFOA can induce adipogenic differentiation in preadipocytes, and the underlying mechanisms probably involve the activation of PPARγ transcription and demethylation of PPARγ promoter.