LIPID METABOLISM: Edited by Marit Westerterp and Bart van de SluisApolipoprotein C-III in triglyceride-rich lipoprotein metabolismRamms, Bastiana,b,c; Gordts, Philip L.S.M.a,bAuthor Information aDepartment of Cellular and Molecular Medicine bDivision of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, La Jolla, San Diego, California, USA cDepartment of Chemistry, Biochemistry I, Bielefeld University, Bielefeld, Germany Correspondence to Philip L.S.M. Gordts, 9500 Gilman Drive, University of California, Department of Medicine, San Diego, La Jolla, CA 92093–0687, USA. Tel: +1 858 246 0994; e-mail: email@example.com Current Opinion in Lipidology: June 2018 - Volume 29 - Issue 3 - p 171-179 doi: 10.1097/MOL.0000000000000502 Buy Metrics Abstract Purpose of review Apolipoprotein (apo) C-III is a key player in triglyceride-rich lipoprotein metabolism and strongly associated with elevated plasma triglyceride levels. Several new studies added important insights on apoC-III and its physiological function confirming its promise as a valid therapeutic target. Recent findings APOC3 is expressed in liver and intestine and regulates triglyceride-rich lipoprotein (TRL) catabolism and anabolism. The transcriptional regulation in both organs requires different regulatory elements. Clinical and preclinical studies established that apoC-III raises plasma triglyceride levels predominantly by inhibiting hepatic TRL clearance. Mechanistic insights into missense variants indicate accelerated renal clearance of apoC-III variants resulting in enhanced TRL catabolism. In contrast, an APOC3 gain-of-function variant enhances de novo lipogenesis and hepatic TRL production. Multiple studies confirmed the correlation between increased apoC-III levels and cardiovascular disease. This has opened up new therapeutic avenues allowing targeting of specific apoC-III properties in triglyceride metabolism. Summary Novel in vivo models and APOC3 missense variants revealed unique mechanisms by which apoC-III inhibits TRL catabolism. Clinical trials with Volanesorsen, an APOC3 antisense oligonucleotide, report very promising lipid-lowering outcomes. However, future studies will need to address if acute apoC-III lowering will have the same clinical benefits as a life-long reduction. Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.