ROLE OF cAMP IN OXIDATIVE STRESS RESPONSES INTRYPANOSOMA CRUZI

TAMARA STERNLIEB; ALEJANDRA C. SCHOIJET; MARÍA J. FIGUERAS; PATRICIO GENTA

Buenos Aires

Congreso; XXVII Reunión Anual de la Sociedad Argentina de Protozoología; 2015

Sociedad Argentina de Protozoología

Cyclic adenosine monophosphate (cAMP) is a key second messenger in several metabolic pathways. In Trypanosoma cruzi itwas found to participate in proliferation, differentiation and osmoregulation. Here we explore the role of cAMP in theresponse to oxidative stress in T. cruzi epimastigotes. To determine the role of cAMP in the oxidative stress response, wefirst set up the conditions for a proliferation measurement method using tritiated thymidine, based on the incorporation ofthe radioactive nucleotide during DNA replication. Through this technique, we established an optimal work concentrationof hydrogen peroxide of 150 μM, which presents a moderate effect over proliferation, allowing the recovery of theparasites? normal growth 24 h later. Our results suggest a possible protective effect of cAMP analogs (pCPT-AMPc and 8-Bromoadenosine 3′,5′-cyclic monophosphate) over the hydrogen peroxide stressed cells. We also generated transgenicparasite lines that overexpress different phosphodiesterases and assessed their involvement in these responses. In the nearfuture, we are going to evaluate the effect of oxidative stress on trypomastigotes infectivity in culture. After incubation oftrypomastigotes with hydrogen peroxide, we will infect Vero cells and measure the percentage of infected cells and thenumber of intracellular amastigotes with Giemsa staining. In addition, we will apply a quantitative colorimetric assay, usingthe oxidation-reduction indicator resazurin as a dye, to assess viability. Taken together, our results unveil an unknown rolefor cAMP as a protective regulator against oxidative stress in T. cruzi and point to identify potential components of thesesignaling pathways.