GW7647 and Rosiglitazone treated human differentiated adipocytes

Objective : This work aimed at characterizing PPARα involvement in metabolism regulation and at comparing PPARα and PPARγ roles in human white adipocytes. Research Design and Methods : Profiling of gene expression alterations was assessed with microarrays and RT-qPCR. Primary cultures of human adipocytes were treated with PPARα agonist GW7647 or PPARγ agonist Rosiglitazone. Western blot were used to determine protein level modifications. Metabolic changes were evaluated with palmitate and glucose oxidation studies and with metabolite measurements. Results : GW7647 induces an upregulation of β-oxidation gene expression and increases palmitate oxidation. Unexpectedly glycolysis was strongly reduced at transcriptional and functional levels by GW7647 while the overall glucose oxidation remains unaltered, leading to a decrease in pyruvate and lactate production. Moreover lipogenesis was downregulated by GW7647 inhibiting triglyceride esterification and de novo lipogenesis. GW7647 induced alterations were abolished by a PPARα antagonist treatment and were clearly different from Rosiglitazone effects. Rosiglitazone had no major impact on glycolysis and β-oxidation but increased glucose incorporation into glycerol backbone of triglycerides. Conclusions : Altogether these results show that PPARα can upregulate β-oxidation in human white adipocytes. Its pharmacological activation may be used to oxidize fatty acids in situ when lipolysis is activated thus preventing their release into systemic circulation. We treated four adipocyte cultures, each one coming from different subjects, with GW7647, Rosiglitazone (ROSI) or DMSO. DMSO treated cells are control samples. Thus we have four paired sample groups for each treatment (GW7647 and ROSI).