Fig 1: Effects of PPARa activators (fenofibrate and WY-14643) and PPARa inhibitor (GW6471) on cell proliferation and differentiation: (A) The effect of PPARa ligands on undifferentiated and sodium butyrate differentiated HT-29 cells. Relative cell proliferation measured by WST-1 assay. Results are shown as the mean ± SD (n = 9). Relative expression of villin and intestinal alkaline phosphatase (IAP) in comparison to the control was measured by In-Cell ELISA. Results are shown as the mean ± SD (n = 6). The red dotted lines represent control cells: DMSO-treated undifferentiated or differentiated cells (100%). (B) Co-localisation of PPARa and villin expression in HT-29 cells. The cells were treated with 150 µM fenofibrate (PPARa activator) and 10 µM GW6471 (PPARa inhibitor). Fenofibrate treatment favoured nuclear localisation of PPARa, whereas GW6471 treatment retained PPARa in cytoplasm. The villin expression was independent of subcellular localisation of PPARa. All microphotographs are in the same magnification (400x); the white line represents 10 µm. (C) Effect of PPARa ligands on undifferentiated and spontaneously differentiated Caco2 cells. Relative cell proliferation measured by WST-1 assay. Results are shown as the mean ± SD (n = 9). Relative expression of villin in comparison to the control was measured by In-Cell ELISA. Results are shown as the mean ± SD (n = 6). The red dotted line represents control cells: DMSO-treated undifferentiated or differentiated cells (100%). Note the increase in villin expression in both used cell lines after PPARa treatment (red rectangles). Statistically significant results in comparison to control cells are marked by * p = 0.05, ** p = 0.01, *** p = 0.001.