Acetyl-CoA Carboxylase Inhibition Reverses NAFLD and Hepatic Insulin Resistance but Promotes Hypertriglyceridemia in Rodents : Hepatology

Abstract

<p class="first" id="P1">Pharmacologic inhibition of acetyl-CoA carboxylase (ACC) enzymes, ACC1 and ACC2, offers an attractive therapeutic strategy for non-alcoholic fatty liver disease (NAFLD) via simultaneous inhibition of fatty acid synthesis and stimulation of fatty acid oxidation. However, the effects of ACC inhibition on hepatic mitochondrial oxidation, anaplerosis, and ketogenesis <i>in vivo</i> are unknown. Here, we evaluated the impact of a novel liver-directed allosteric inhibitor of ACC1 and ACC2 (Compound 1) on these parameters, as well as glucose and lipid metabolism, in control and diet-induced rodent models of NAFLD. Oral administration of Compound 1 preferentially inhibited ACC enzymatic activity in the liver, reduced hepatic malonyl-CoA levels and enhanced hepatic ketogenesis by 50%. Furthermore, administration for 6 days to high-fructose fed rats resulted in a 20% reduction in hepatic <i>de novo</i> lipogenesis. Importantly, long-term treatment (21 days) significantly reduced high-fat sucrose diet (HFSD)-induced hepatic steatosis, PKCε activation and hepatic insulin resistance. ACCi treatment was associated with a significant increase in plasma triglycerides (∼30 to 130%, depending on length of fasting). ACCi-mediated hypertriglyceridemia could be attributed to a ∼15% increase in hepatic VLDL production and ∼20% reduction in triglyceride clearance by lipoprotein lipase (LPL) ( <i>P</i> ≤ 0.05). At the molecular level, these changes were associated with increases in LXR/SREBP1 and decreases in PPARα target activation and could be reversed with fenofibrate co-treatment in a high-fat diet mouse model. Collectively, these studies warrant further investigation into the therapeutic utility of liver-directed ACC inhibition for the treatment of NAFLD and hepatic insulin resistance. </p>