Involvement of AMPK in the pharmacological stimulation of the autophagic pathway in Echinococcus multilocularis

JULIA A LOOS; RAPHAËL DUVOISIN; KLAUS BREHM; CUMINO ANDREA C.

Mar del Plata

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

Sociedad Argentina de Investigación Clínica

Echinococcosis is a neglected zoonotic disease caused by infection with the larval stage of tapeworms within the genus Echinococcus spp. In order to develop strategies for echinococcosis treatment and control, it is necessary to highlight basic studies on the parasite larval stage and to identify possible new molecular targets, particularly in those signal transduction pathways on which parasite cells depend for their survival. The AMP-activated protein kinase (AMPK) is one of the central regulators of metabolism in eukaryotes and plays a critical role in the cell growth and autophagy regulation. The most thoroughly described mechanism by which AMPK regulates these cellular processes is through suppression of the TOR pathway. Recently, it was demonstrated that, under in vitro conditions, E. granulosus larval stage is susceptible to metformin (Met) and that this drug indirectly activates Eg-AMPK, as a consequence of cellular energy charge depletion. Therefore this kinase could be highly relevant to Echinococcus spp. Here, we initiated a functional analysis of AMPK in the E. multilocularis experimental model. By in toto immunolocalization assays, we detected the expression and subcellular localization of Em-AMPK and Em-LC3 (autophagy marker) in the germinal layer of in vitro obtained metacestodes vesicles. Interestingly, a different expression pattern of Eg-LC3 was observed between control and Met-treated samples. In addition, by qPCR analysis, we found that Met produced a dose-dependent increase in Em-lc3 transcript levels in parasite primary cells. Subsequently, using RNA interference, we achieved a significant reduction in transcript abundance and protein expression levels for Em-ampkα. The Em-AMPK knockdown partially prevented the inductor effect of the drug on the Em-lc3expression. Therefore, AMPK might be to some extent necessary for the regulation of Met-stimulated autopahgic process in Echinococcus spp. However, further studies are needed to clarify this issue.