Leishmania chagasi: An ecto-3′-nucleotidase activity modulated by inorganic phosphate and its possible involvement in parasite–macrophage interaction

Adenosine and 3′ AMP added during the Leishmania chagasi macrophage interaction increased adhesion at the same rate. Parasites grown at low Pi concentration, expressing higher ecto-3′-nucleotidase activity, infected more marcophages than Parasites grown at high Pi. [Display omitted] ►L. chagasi was able to hydrolyze 3’AMP ten times more than 5’AMP. ► Parasites grown in low Pi concentration decreased cell growth compared to those grown in high Pi concentration. ► Ecto-3’nucleotidase activity increased when L. chagasi was grown in a low Pi concentration. ► Altogether, the results describe an ecto-3’nucleotidase activity that could be involved on parasite-macrophage interaction. In this work we showed that living cells of Leishmania chagasi was able to hydrolyse 3′AMP 10 times more than 5′AMP. When parasites were grown in a low phosphate concentration (2mM) the cellular proliferation decreased by 50% compared to cells grown in the presence of a high phosphate concentration (80mM). However, the ecto-3′nucleotidase activity was 2-fold higher when L. chagasi was grown in a low phosphate concentration. This modulation observed on ecto-3′nucleotidase activity was not observed on ecto-5′nucleotidase activity. These results suggest that low concentration of Pi in the culture medium modulates ecto-3′nucleotidase activity that may lead to modulation of important processes for the cell. Interestingly, the macrophage–parasite interaction increased by 45% when L. chagasi were grown at low phosphate concentration compared to the parasites grown in the presence of high phosphate source. Altogether, the results described here suggest that 3′nucleotidase activity modulated by external stimuli, Pi concentration, could be involved on parasite–macrophage interaction.