Lipid droplets dynamics and the response to pharmacological treatment in Echinococcus granulosus.

DÁVILA VALERIA A.; CUMINO ANDREA C.

Mar del Plata

Congreso; LXI Reunión Anual de la Sociedad Argentina de Investigación Clínica; 2016

Sociedad Argentina de Investigación Clínica

Uptake of fatty acids seems to be crucial for Echinococcus spp. since cestode lack the ability to synthesize fatty acids and cholesterol de novo, and, as flukes, have lost many genes associated with the peroxisome, essential in the occurrence of fatty acid oxidation. Lipid droplets (LDs) are conserved organelles for intracellular neutral lipid storage with high metabolic activity, whose functions are not limited to passive stock of lipids, being the maintenance of endoplasmic reticulum (ER) homeostasis a critical one. Mobilization of lipids in LDs occurs through lipolysis and autophagy. Here, we attempt to characterize these organelles and their dynamic in response to different drugs by confocal and electron transmission microscopy. We identified a high basal level of LDs in Echinococcus larval stage, possible due to its low UPR capacity and high sensibility ER stress. In close connection with ER, we identified smaller LD associated with nuclei compared with those in the cytoplasm. Moreover, changes on size, number and cell distribution of LDs during metformin, rapamycin and indomethacin treatments were detected. We also verified the power of oleic acid (18:9 n-1, monosaturated fatty acid), the most abundant fatty acid in the diet and serum of human host, as a potential autophagic inductor and promoter of LDs formation. On the other hand, expression of hormone sensible and lisosomal acid lipases (Eg-lal1, Eg-lal2 and Eg-hsl), different autophagy-related genes (atg1 to atg18), FoxO and TFBE were analyzed by RT-PCR and qPCR from drug-treated protoscoleces and metacestodes. Finally the colocalization of Eg-Atg8-Alexa-Fluor 488 and bodipy 493/503 by in toto immunofluorescence was performed in protoscoleces, suggesting the importance of autophagy in the regulation of LDs. Our results allowed us to conclude that Echinococcus lipid store can be modulated by different metabolic and pharmacological conditions.