CrATP interferes in the promastigote-macrophage interaction inLeishmania amazonensisinfection

Abstract

Recent have shown the relationship between Ecto-Nucleoside-Triphosphate-Diphosphohydrolases (Ecto-NTPDases or ecto-nucleotidases) and virulence and infectivity in trypanosomatids. In this work, the inhibition of the ecto-ATPase activities and promastigote growth of Leishmania amazonensis by CrATP was characterized. Furthermore, this compound was used to investigate the role of ecto-nucleotidase in the interaction of L. amazonensis with resident peritoneal macrophages obtained from BALB/c mice. CrATP partially inhibits the ecto-ATPase activity, presenting Ki values of 575·7±199·1 and 383·5±79·0 μm, in the presence or absence of 5 mm MgCl2, respectively. The apparent Kms for ATP (2·9±0·5 mm to Mg2+-dependent ecto-ATPase and 0·4±0·2 mm to Mg2+-independent ecto-ATPase activities) are not significantly altered by CrATP, suggesting a reversible non-competitive inhibition of both enzymes. When CrATP was added to the cultivation medium at 500 μm, it drastically inhibited the cellular growth. The interaction of promastigote forms of L. amazonensis with BALB/c peritoneal macrophages is strongly affected by CrATP. When the parasites were treated with 500 μm CrATP before interacting with macrophages, the adhesion and endocytic indices were strongly reduced to 53·0±14·8% and 39·8±1·1%, respectively. These results indicate that ecto-nucleotidase plays an important role in the infection process caused by Leishmania amazonensis.

Nucleoside triphosphate diphosphohydrolase1 (TcNTPDase-1) gene expression is increased due to heat shock and in infective forms of Trypanosoma cruzi

“…There are lines of evidence that NTPDases are related to virulence and infectivity in protozoan parasites [19][20][21][22][23]. However, most of the studies reported ecto-NTPDase enzymatic activities in intact parasites or plasma membrane fractions.…”

Periodate‐oxidized ATP modulates macrophage functions during infection with Leishmania amazonensis

“…This activity is important to the organism because these parasites do not have the ability to perform de novo purine synthesis, allowing them to acquire nucleosides. Furthermore, there is a hypothesis that ecto-NTPDases could act as adhesion molecules that facilitate parasitic infection (48). Furthermore, there is a hypothesis that ecto-NTPDases could act as adhesion molecules that facilitate parasitic infection (48).…”

“…It is possible that the ability to cleave ATP, a pro-inflammatory molecule, and to generate adenosine, an anti-inflammatory molecule, is involved in the regulation of the immune response triggered by the parasite Leishmania (47). Furthermore, there is a hypothesis that ecto-NTPDases could act as adhesion molecules that facilitate parasitic infection (48). Our results showing that oATP impaired ecto-ATPase activity in macrophages with a less pronounced effect on Leishmania and the previously demonstrated reduction in in vitro and in vivo infectivity of Leishmania promastigotes maintained for a long period in axenic culture are both associated with reduced hydrolytic activity of ATP and ADP (49), and suggest that the activity of these enzymes may be a virulence factor.…”

NTPDase activities: possible roles on Leishmania spp infectivity and virulence

“…Moreover, the adhesion and endocytic indices were significantly reduced when the promastigotes were treated with CrATP before the interaction with BALB/c peritoneal macrophages, suggesting that the ecto‐ATPase exerts a crucial role in the macrophage invasion process. Interestingly, washing the CrATP‐treated promastigotes before the interaction assay restored the endocytic and adhesion indices (Ennes‐Vidal et al, ).…”