Figure 4

PPARγ isoforms equally decrease de novo lipogenesis and oxidative stress, but differentially modulate triglyceride saturation and glucose metabolism. (a) Ectopic expression of PPARγ1 or PPARγ2 in mPrE-PPARγKO cells resulted in decreased activation of lipogenic pathways including Akt, mTOR, Fasn and Acc. In addition, Cox-2 levels were decreased indicative of lower levels of ROS. (b) Dihydroethidium staining followed by flow cytometry (N=3) confirmed a decrease in ROS. (c) Fatty acid analysis of triglycerides by TLC/MS revealed increased levels and saturation of stearic acid (increased 18 : 0, decreased 18 : 1n9) in PPARγ1-restored cells compared to +EV cells (N=3), consistent with the decreased expression of Scd1 (see Table 1). (d) Glucose/lactate flux analysis in mPrE-PPARγKO+EV, +PPARγ1 or +PPARγ2 cells over 4 days (2 time points/day) demonstrated significantly decreased glucose uptake in mPrE-PPARγKO+PPARγ1 cells and significantly increased lactate secretion in mPrE-PPARγKO+PPARγ2 cells compared to +EV cells. (e) IC50 analysis of the glucose oxidation inhibitor 2DG suggested a reliance of mPrE-PPARγKO+EV cells on glucose in the absence of +PPARγ1 or +PPARγ2 cells, which highly regulate fatty acid transport and metabolism (see Table 1). *P value <0.05