Expression of endoplasmic reticulum associated hepatic lipase lowers triacylglycerol storage and secretion in rat liver cells

PARAMADAYALAN, SENTHAMIL; ERICKSON, BRUCE; KO, KERRY; KELLY, KAREN; QUIROGA, ARIEL DARIO; YAO, Z; KING-JONES, K; JACOBS, RENE; LEHNER, RICHARD

Edmonton

Jornada; Alberta Diabetes Institute (ADI) Research Day; 2010

Excessive hepatic triacylglycerol (TG) storage is intimately linked withinsulin resistance, metabolic syndrome and cardiovascular diseases.Hepatic TG levels are regulated by TG synthesis, degradation (lipolysisand oxidation of released fatty acids) and secretion. Despite the crucialrole of lipolysis in the provision of substrates for fatty acid oxidation andfor the assembly of apoB-containing very-low density lipoproteins, theidentities of hepatic lipases and the metabolic consequence of theiraction remains ill-defined.Hepatic lipase (HL) exhibits phospholipase A1 and TG hydrolase activitiesand has an important function in lipid metabolism. It is secreted from theliver and can be found either bound to cell-surface heparan sulfateproteoglycans or circulating in blood. HL hydrolyzes plasma lipidsassociated with high-density lipoproteins (HDL) and with apolipoproteinB (apoB)-containing lipoproteins (VLDL). Aside from its lipolytic function,HL also facilitates the selective uptake of cholesteryl esters (CE) fromHDL as well as the removal of apoB-containing lipoprotein remnants viareceptor mediated endocytosis.