INSIGHTS INTO RESPONSES TO STRESS CONDITIONS MEDIATED BY ADENOSINE NUCLEOTIDES IN TRYPANOSOMA CRUZI

TAMARA STERNLIEB; ALEJANDRA C. SCHOIJET; MIRTHA M. FLAWIA; GUILLERMO D. ALONSO

Mar del Plata, Buenos Aires.

Congreso; X Congreso de Protozoología y enfermedades parasitarias; 2014

Sociedad Argentina de Protozoología

Cyclic adenosine monophosphate (cAMP) is a key second messenger in several metabolic pathways. In Trypanosoma cruzi it was found to participate in proliferation, differentiation and osmoregulation. Here we explore the role of cAMP in the responses to oxidative and nutritional stress in T. cruzi epimastigotes. To determine the role of cAMP in oxidative stress, we established an optimal work concentration of hydrogen peroxide of 150 µM, which presents a moderate effect, allowing the recovery of the parasites? normal growth 24 h later. Our results suggest a possible protective effect of cAMP analogs (Dibutyryl-cAMP and 8-Bromoadenosine 3′,5′-cyclic monophosphate) over the stress produced. We will continue analyzing this effect using Phosphodiesterases (PDEs) and Adenylate cyclase inhibitors. Currently, we are working to identify which PDE is involved in this response. In addition, and to deepen our research on stress responses in T. cruzi, we are studying the AMP-activated protein kinase (AMPK). This heterotrimeric enzyme is involved in maintaining energy homeostasis in response to nutrient stress in many organisms. The α subunit contains a kinase domain as well as a regulatory domain that inhibits the enzyme in the absence of AMP. The β subunit acts as a scaffold for the other components, while the γ subunit is thought to be involved in AMP binding. We have already identified the genes corresponding to β and γ subunits in T. cruzi and both have been cloned into vectors for E. coli and epimastigotes expression. Furthermore, AMP binding assays will be performed using the purified recombinant β subunit. Finally, to investigate the role in vivo of this enzyme, parasites will be transfected with both genes, and their product activity will be evaluated using synthetic activators. Taken together, our results unveil an unknown role for cAMP as a protective regulator against oxidative stress in T. cruzi and point to identify potential components of these signaling pathways.