Nuclear lipid droplets are dynamics structures

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

Congreso; Reunion Anual de la SAIB; 2012

The cell nucleus (N) is a highly compartmentalized organellecharacterized by several dynamic domains. We have demonstratedthat nuclear neutral lipids are organized and stored in lipid droplets(nLD), composed of few and small droplets randomly distributed.The nLD could thus be involved in nuclear-lipid homeostasis andserve as an endonuclear buffering system that can rapidly providesor incorporates lipids involved in signaling paths and transcriptionfactors in the nucleus.The aim of this work was to determine if nLD are a dynamicdomain. With this purpose HepG2 were incubated with 18:1n-9 asan external stimulus since it increases cytosolic lipid droplet (cLD)number and size. Both LD (c and n) were stained withBODIPY493/503 and N with DAPI and viability controls weredone. Due to 18:1n-9 treatment cellular shape was modified andboth cLD and nLD increased (number and size). nLD incrementswere smaller than cLD (4 and 10 times respectively). If 18:1n-9was excluded from the incubation mixture, LD increments werereverted. Under all conditions tested, nLD corresponded to a smallpool (3-5%) with respect to total (nLD + cLD).In conclusion, nLD are dynamic structures; their size and numbercan vary in response to external signals that influence TAG poolsby a reversible mechanism.