Hepatocyte-specific suppression of ANGPTL4 improves obesity-associated diabetes and mitigates atherosclerosis in mice

AK Singh, B Chaube, X Zhang, J Sun… - The Journal of …, 2021 - Am Soc Clin Investig
AK Singh, B Chaube, X Zhang, J Sun, KM Citrin, A Canfrán-Duque, B Aryal, N Rotllan…
The Journal of Clinical Investigation, 2021Am Soc Clin Investig
Hepatic uptake and biosynthesis of fatty acids (FAs), as well as the partitioning of FAs into
oxidative, storage, and secretory pathways, are tightly regulated processes. Dysregulation of
one or more of these processes can promote excess hepatic lipid accumulation, ultimately
leading to systemic metabolic dysfunction. Angiopoietin-like-4 (ANGPTL4) is a secretory
protein that inhibits lipoprotein lipase (LPL) and modulates triacylglycerol (TAG)
homeostasis. To understand the role of ANGPTL4 in liver lipid metabolism under normal and …
Hepatic uptake and biosynthesis of fatty acids (FAs), as well as the partitioning of FAs into oxidative, storage, and secretory pathways, are tightly regulated processes. Dysregulation of one or more of these processes can promote excess hepatic lipid accumulation, ultimately leading to systemic metabolic dysfunction. Angiopoietin-like-4 (ANGPTL4) is a secretory protein that inhibits lipoprotein lipase (LPL) and modulates triacylglycerol (TAG) homeostasis. To understand the role of ANGPTL4 in liver lipid metabolism under normal and high-fat–fed conditions, we generated hepatocyte-specific Angptl4 mutant mice (Hmut). Using metabolic turnover studies, we demonstrate that hepatic Angptl4 deficiency facilitates catabolism of TAG-rich lipoprotein (TRL) remnants in the liver via increased hepatic lipase (HL) activity, which results in a significant reduction in circulating TAG and cholesterol levels. Consequently, depletion of hepatocyte Angptl4 protects against diet-induced obesity, glucose intolerance, liver steatosis, and atherogenesis. Mechanistically, we demonstrate that loss of Angptl4 in hepatocytes promotes FA uptake, which results in increased FA oxidation, ROS production, and AMPK activation. Finally, we demonstrate the utility of a targeted pharmacologic therapy that specifically inhibits Angptl4 gene expression in the liver and protects against diet-induced obesity, dyslipidemia, glucose intolerance, and liver damage, which likely occur via increased HL activity. Notably, this inhibition strategy does not cause any of the deleterious effects previously observed with neutralizing antibodies.
The Journal of Clinical Investigation