ROLE OF cAMP IN OXIDATIVE STRESS RESPONSES IN TRYPANOSOMA CRUZI

STERNLIEB T; SCHOIJET AC; FIGUERAS MJ; GENTA PD; FLAWIÁ MM; ALONSO GD

CABA

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 it was found to participate in proliferation, differentiation and osmoregulation. Here we explore the role of cAMP in the response to oxidative stress in T. cruzi epimastigotes. To determine the role of cAMP in the oxidative stress response, we first set up the conditions for a proliferation measurement method using tritiated thymidine, based on the incorporation of the radioactive nucleotide during DNA replication. Through this technique, we established an optimal work concentration of hydrogen peroxide of 150 μM, which presents a moderate effect over proliferation, allowing the recovery of the parasites? 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 transgenic parasite lines that overexpress different phosphodiesterases and assessed their involvement in these responses. In the near future, we are going to evaluate the effect of oxidative stress on trypomastigotes infectivity in culture. After incubation of trypomastigotes with hydrogen peroxide, we will infect Vero cells and measure the percentage of infected cells and the number of intracellular amastigotes with Giemsa staining. In addition, we will apply a quantitative colorimetric assay, using the oxidation-reduction indicator resazurin as a dye, to assess viability. 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.