INVESTIGADORES
LOOS Julia Alexandra
congresos y reuniones científicas
Título:
Autophagy as a common cell death mechanism during the pharmacological treatment of Echinococcus granulosus larval stage.
Autor/es:
JULIA A. LOOS; PEDRO A. CAPARROS; M. CELESTE NICOLAO; ANDREA C. CUMINO
Lugar:
Guayaquil
Reunión:
Congreso; XXI Congreso Latinoamericano de Parasitología (FLAP); 2013
Resumen:
Introduction
Autophagy is a conserved lysosomal pathway in which cells degrade organelles to generate energy.
A key regulator of autophagy is TORC1 and its pharmacological inhibition, through rapamycin or
metformin, induces this catabolic process. Previously we verified that rapalogs and metformin increased
the accumulation of cytoplasmic acidic organelles, suggesting autophagy induction as cell-death mechanism.
Additionally, the detection of autophagosomes is a common denominator in antiechinococcal drug screening
reports. Here, we evidenced the molecular components of the autophagy machinery in basal
conditions and demonstrated its overexpression under pharmacological treatment in Echinococcus
granulosus.
Materials and methods
We tested As2O3, potential autophagic inductor, as a new compound against the larval stages. Using
tBLASTn we have identified orthologs to all the proteins involved in the autophagosome formation.
Expression of different autophagy-related genes (atg1 to atg18), Tor and raptor were analyzed by
RT-PCR and qPCR from drug-treated protoscoleces and metacestodes. SEM and TEM were used to
investigate ultrastructural damage and autophagosome progress. Also, we performed in toto
immunofluorescence and western blot assays in protoscoleces to determine the expression and
localization of Eg-Atg8/LC3. Finally, we analyzed by MEB-EDX the composition, structure and
Eg-Atg8/LC3 expression in protoscolex calcareous corpuscles. Data were compared using the
Student´s t-test.
Results
In this work treatment with As2O3 inhibited viability in a dose-dependent manner in protoscoleces and
metacestodes. Cyst ultrastructural damages appeared earlier with detachment of the germinal layers and
autophagic structures were evidenced. Rapamicyn and As2O3 upregulated the LC3II expression, Eg-atg6-8-
12-16 and Eg-atg18 in both larval stages. Eg-Atg8/LC3 protein was immunodetected in the tegument,
the excretory system and the calcareous corpuscles of control and treated protoscoleces.
Colocalization of arsenic with the principal ions found in calcareous corpuscles was detected, and
different degrees of development of the corpuscles were identified.
Conclusion
In Echinococcus either the induction or the inhibition of autophagy can provide therapeutic benefits
to hydatidosis treatment.