Figure 7. UCP2 is required for the fenofibrate-mediated protective activity against LPS-induced lethal shock.

(A) BMDMs were transduced with lentivirus expressing nonspecific shRNA (shNS) or shRNA specific for UCP2 (shUCP2), followed by treatment with fenofibrate (50 µM; 4 h) and stimulation with LPS (100 ng/ml; 18 h). The supernatants were collected and protein expression of TNF-α, IL-6, and IL-8 was determined using ELISA. (B) Immunoblot analysis of HMGB1 protein in whole cell lysate (WCL) and supernatant (SN). (C to F) Mice were injected with lentivirus (1×10⁹ pfu; administered intravenously) expressing nonspecific shRNA (shNS) or shRNA specific for UCP2 (shUCP2) with polybrene (8 µg/mL) for 2 consecutive days and then orally administered fenofibrate for 7 consecutive days before LPS challenge (30 mg/mL, i.p). (C) Expression of UCP2 in liver and spleen at 2 and 7 days after i.v. infection with lentivirus was assessed by immunoblotting (IB). Whole cell lysates (WCL) were used for IB with anti-Actin. (D) The survival of mice (n = 10 mice per group) was monitored for 84 h. Results are presented as the mean ± SEM. n.s., non-specific (log-rank test). (E) Sera were collected from each group (n = 5) at 18 h after i.p LPS injection and the concentrations of TNF-α, IL-6, and IL-1β were measured using ELISA. (F) Representative immunofluorescence images for expression of COX-2 in spleen tissues from each group. Scale bar, 50 µm. The data (B, C, and F) are representative of at least three independent experiments with similar results. Quantitative data are shown as the mean ± SD of three experiments (A and E). Statistical differences (**, p<0.01; ***, p<0.001) are indicated (paired t-test with Bonferroni adjustment). FF, fenofibrate.