title: Apolipoprotein A5: Extracellular and Intracellular Roles in Triglyceride Metabolism.
abstract: This review addresses two major functions of apolipoprotein (apo) A5 including (1) its role in maintaining normal plasma levels of circulating triglyceride (TG) and (2) its role as a component of hepatic lipid droplets. ApoA5 is synthesized solely in the liver and circulating concentrations are extremely low. In the plasma, ApoA5 associates with TG-rich lipoproteins and enhances TG hydrolysis and remnant lipoprotein clearance. ApoA5 loss-of-function single nucleotide polymorphisms are associated with reduced lipolysis, poor remnant clearance and concomitantly, hypertriglyceridemia. Although there have been substantial breakthroughs in understanding pathophysiology associated with secreted ApoA5, there is a paucity of knowledge on the functionality of intracellular ApoA5. However, recent studies indicate that overexpression of intracellular ApoA5 is positively associated with accumulation of TG-rich lipid droplets in hepatocytes. It is thought that ApoA5 may have a causal role in non-alcoholic fatty liver disease (NAFLD) and thus, may serve as a target for developing therapeutics for NAFLD.
authors.affiliation: Center for Prevention of Obesity, Diabetes and Cardiovascular Disease, Children`s Hospital Oakland Research Institute, Oakland, CA 94609, USA. tforte@chori.org.
authors.forename: Trudy M
authors.initials: TM
authors.lastname: Forte
authors.forename: Robert O
authors.initials: RO
authors.lastname: Ryan
mesh_terms: D000072040:Apolipoprotein A-V; D001054:Apolipoproteins A / Q000235:genetics / Q000502:physiology*; D006801:Humans; D015228:Hypertriglyceridemia / Q000235:genetics; D008099:Liver / Q000378:metabolism / Q000502:physiology; D065626:Non-alcoholic Fatty Liver Disease / Q000503:physiopathology; D020641:Polymorphism, Single Nucleotide; D014280:Triglycerides / Q000378:metabolism*
chemical_list: C437704:APOA5 protein, human; D000072040:Apolipoprotein A-V; D001054:Apolipoproteins A; D014280:Triglycerides