Holzmuller Philippe, Hide Mallorie, Sereno Denis, Lemesre Jean-Loup. (2006). Leishmania infantum amastigotes resistant to nitric oxide cytotoxicity: Impact on in vitro parasite developmental cycle and metabolic enzyme activities. Infection Genetics and Evolution, 6 (3), p. 187-197. ISSN 1567-1348.
Titre du document
Leishmania infantum amastigotes resistant to nitric oxide cytotoxicity: Impact on in vitro parasite developmental cycle and metabolic enzyme activities
Infection Genetics and Evolution, 2006,
6 (3), p. 187-197 ISSN 1567-1348
Nitric oxide (NO) has been demonstrated to be the principal effector molecule mediating intracellular killing of Leishmania. The free radical characteristic of NO prevented direct induction of resistance in Leishmania wild-type parasites. Starting from the previous observation that antimony-resistant amastigotes of Leishmania infantum were not affected by NO-induced apoptotic death, we used a continuous NO pressure protocol and succeeded in inducing NO resistance in amastigote forms of L. infantum. Two clones resistant to 50 mu M (LiNOR50) and 100 mu M (LiNOR 100) of the NO donor DETA/NONOate, derived from parental clone weakly resistant to trivalent antimony (LiSbIIIR4), were selected and analysed. Both clones were also resistant to other NO donors, particularly SNAP In the absence of potassium antimonyl tartrate, all clones (LiSbIIIR4, LiNOR50 and LiNOR100) lost their antimony resistance almost totally. Interestingly, the parasitic developmental life cycle of NO-resistant mutants was dramatically disturbed. NO-resistant amastigotes differentiated more rapidly into promastigotes than the wild-type ones. Nevertheless, NO-resistant amastigotes produce a maximal number of parasites 1.5-2 times lower than the wild-type whereas, after differentiation, NO-resistant promastigotes produced more cells than the wild-type. We showed that this last phenomenon could be a consequence of the overexpression of parasitic enzymes involved in both glycolysis and respiration processes. NO-resistant amastigotes overexpressed three enzymes: cis-aconitase, glyceraldehyde-3-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. The two first enzymes are NO molecular targets which could be directly involved in NO resistance and the third one could interfere in modifying Leishmania metabolism. (c) 2005 Elsevier B.V. All rights reserved.
