Fig. 3.

Phosphorylation of Akt and PARP cleavage are not influenced by ligand activation of PPARβ/δ in HaCaT cells. HaCaT cells were treated for 12 h with either GW0742 (A and C) or GW501516 (B and D) with the indicated concentration of ligand in the presence (A and B) or absence (C and D) of serum as described under Materials and Methods to examine the quantitative expression of phosphorylated Akt and PARP cleavage. Values are the average -fold change compared with control treatment and represent the mean ± S.E.M. Values with different letters are significantly different, P < 0.05, as determined by ANOVA and Bonferroni’s multiple comparison test. The cleavage ratio is an indicator of apoptosis and is the average ratio of cleaved PARP to uncleaved PARP normalized values. E, Western blot analysis demonstrating specificity of the phospho-Akt antibody. Rat cerebrum lysate (+) was used as a positive control and representative samples from HaCaT cells treated with either GW0742, atRA, or 9-cis RA were used comparison. Phospho-Akt has a molecular mass of 60 kDa.