Fig. 1.

Peroxisome proliferator-activated receptor α (PPARα) is downregulated in Pkd1^RC/RC mice. A: quantitative PCR (Q-PCR) analysis showed that Ppara expression was reduced by 35.1% in the kidneys of 200-day-old Pkd1^RC/RC mice (n = 8) compared to age-matched wild-type control mice (n = 3). B and C: Western blot analysis and quantification demonstrated that PPARα protein expression was reduced 65.6% in Pkd1^RC/RC mice (n = 5) compared to wild-type controls (n = 5). Actin was used as the loading control. D: immunofluorescence staining revealed that PPARα (red) expression was specifically reduced in kidney cyst epithelial cells Pkd1^RC/RC mice. E: expression of fatty acid oxidation/oxidative phosphorylation (FAO/OXPHOS) genes regulated by PPARα was measured using Q-PCR. Compared to control mice kidneys (n = 3), Pkd1^RC/RC mice kidneys (n = 6 or 7) demonstrated significant downregulation of FAO/OXPHOS gene expression. F: to determine whether reduced FAO/OXPHOS gene expression resulted in reduced mitochondrial metabolism, wild-type (n = 4) and Pkd1^RC/RC (n = 5) were injected with ³H-labeled triolein tracer to measure in vivo kidney FAO. Oxidation of ³H-labeled triolein was reduced in Pkd1^RC/RC mice kidneys compared to wild-type kidneys. Error bars indicate means ± SE.