Oleic acid stimulates Nuclear Lipid Droplet dynamics

LAGRUTTA, LUCÍA C.; LAYERENZA, JUAN P.; MOTERO VILLEGAS SANDRA; SISTI MARTÍN S.; GARCÍA DE BRAVO, MARGARITA M.; VES LOSADA, ANA

Aberdeen

Conferencia; 55th International Conference on the Biochemistry of lipids, ICBL; 2014

International Conference on the Biochemistry of lipids, ICBL

Neutral lipids are involved in many cellular processes. They are stored as Lipid Droplets (LD) mainly located in cytosol (cLD) and in a small LD population within the nucleus (nLD) that we have recently identified. nLD would be built up around a hydrophobic core of TAG and CE enriched in oleic acid (OA) and surrounded by a monolayer of polar lipids, cholesterol and proteins. nLD could be involved in nuclear-lipid homeostasis and serve as an endonuclear buffering system that can provide or incorporate lipids involved in signaling paths and transcription factors. The aim of the present work was to determine if nLD are a dynamic domain as cLD. The addition of OA to culture of HepG2 cells or primary rat hepatocytes determined cellular shape modification, increased in TAG and CE content and cLD and nLD (number and size); LD increments would be reverted if OA was excluded. cLD and nLD induction by OA was prevented by ACS (acyl-Co-A synthetase) inhibitor (TriacsinC) involved in TAG and CE biosynthesis. Under all conditions tested, nLD corresponded to a small population (3-5%) of cellular LD (nLD+cLD). Both LD types (nLD+cLD) were stained with BODIPY493/503 and nucleus with DAPI. Under these conditions, OA did not cause any toxicity (tested by trypan-blue?dye-exclusion and MTT). In conclusion, nLD are a dynamic nuclear domain as cLD, and both types of LD content are induced by OA by a reversible mechanism that involves ACS activity and TAG and CE biosynthesis.