PPARα activation protects against cholestatic liver injury

Intrahepatic cholestasis induced by drug toxicity, bile salt export pump (BSEP) deficiency, or pregnancy frequently causes cholestatic liver damage, which ultimately may lead to liver fibrosis and cirrhosis. Here, the preventive and therapeutic effects of peroxisome proliferator-activated receptor α (PPARα) signaling activated by fenofibrate was evaluated on cholestatic liver damage. Metabolomic analysis revealed that alpha-naphthyl isothiocyanate (ANIT)-induced intrahepatic cholestasis resulted in the accumulation of serum long-chain acylcarnitines and triglyceride, and the reduced expression of four fatty acid β-oxidation (β-FAO) relevant genes (Cpt1b, Cpt2, Mcad and Hadha), indicating the disruption of β-FAO. The increase of acylcarnitines in hepatic cell resulted in the enhanced expression of anti-oxidative genes glutathione S-transferases (Gsta2 and Gstm3) directly. As direct PPARα-regulated genes, Cpt1b, Cpt2, and Mcad were up-regulated after pretreatment with PPARα agonist, fenofibrate, indicating the improvement of β-FAO. In the end, the disrupted bile acid metabolism in the enterohepatic circulation and the enhanced oxidative stress and inflammation cytokines induced by ANIT exposure were significantly recovered with the improvement of β-FAO using fenofibrate treatment. These findings provide the rationale for the use of PPARα agonists as therapeutic alternatives for cholestatic liver damage.