Skip to main content
. 2005 Mar;25(5):1696–1712. doi: 10.1128/MCB.25.5.1696-1712.2005

FIG. 9.

FIG. 9.

HGF-mediated activation of PPARβ is dependent on COX-2 activity. (A) Colorimetric immunostaining of COX-2 in hair pegs and mature HFs was performed in WT mouse skin at P4 (top panel). Analysis of COX-2 protein expression was carried out at indicated postnatal days. (B, C) Quantitative histomorphometry was done on four different skin explants treated or not for 48 h with 10 or 20 μM of the COX-2 inhibitorNS-398 (NS). Delayed HF morphogenesis was observed in explants treated with NS-398, as reflected by the decrease of the hair morphogenesis score in a dose-dependent manner. Independent Student's t test: *, P < 0.05; **, P < 0.01. Magnification bars, 50 μm. (D) Mouse keratinocytes were transfected with a luciferase reporter construct with or without (control) the proximal promoter of the COX-2 (COX-2 prom.) or PPARβ (PPARβ prom.) genes. The transfected cells were allowed to recover for 24 h and were then treated for another 24 h with 20 or 50 μM HGF (top panel) or not treated (vehicle). The relative n-fold induction in treated versus untreated cells was calculated after normalization to β-galactosidase activity. Values are means of at least three independent experiments. In the bottom panel, Western blot assays were carried out using total cellular proteins extracted from primary keratinocytes derived from PPARβ+/+ and PPARβ−/− mice and treated for 24 h with 20 or 50 μM of HGF or not treated (−). (E) Analysis of the Akt1 pathway by Western blotting was performed in primary keratinocytes derived from PPARβ+/+ and PPARβ−/− mice, treated for 24 h with 20 or 50 μM of HGF or not treated (−), in the absence (−) or presence (+) of 10 μM NS-398 (NS; left panel). Changes, indicated below each band, represent the mean of three independent experiments, after normalization to the untreated PPARβ+/+ or PPARβ−/−. (F) Mouse keratinocytes were transfected with luciferase reporter constructs containing or not containing (control) two copies of ILK or PDK1 PPREs and treated (+) or not treated (−) with 20 μM HGF and/or 10 μM NS-398 (NS). Results represent means of three independent experiments and are expressed as relative n-fold induction.