Figure 5

PCNA and CCN2 expression is enhanced in PPARγ KO (K/K) fibroblasts. Indirect immunofluorescence analysis of WT (C/C) and PPARγ KO (K/K) mice (day 7 and 10 post-wounding) with (A) an anti-PCNA antibody and (B) an anti-CCN2 antibody (C/C: N = 10; K/K: N = 12, original magnification × 20, bar = 50 μm). Red, CCN2;Blue, DAPI. *** = indicates significant difference between C/C and K/K groups (P < 0.001). (C) Real time PCR analysis of WT (C/C) and PPARγ KO (K/K) fibroblasts treated with or without troglitazone (40 μM, 24 hours). Primers detecting CCN2 and 18S mRNAs were used. Expression relative to CCN2 expression in untreated WT (C/C) fibroblasts is shown. Average +/- standard deviation (N = 3) is shown. ** = significant difference between groups (P < 0.01). Note that CCN2 mRNA expression was elevated in (K/K) fibroblasts; troglitazone (+trog) reduced CCN2 mRNA expression in both (C/C) and (K/K) fibroblasts indicating that troglitazone operated independent of PPARγ. DAPI, 4',6-diamidino-2-phenylindole; PCNA, proliferating cell nuclear antigen.; PPARγ, peroxisome proliferator-activated receptor-γ Loss of PPARγ results in enhanced Smad3, Akt and ERK phosphorylation.