Nelfinavir, an HIV-1 protease inhibitor, induces oxidative stress-mediated, caspase-independent apoptosis in Leishmania amastigotes.
BACKGROUND
Visceral leishmaniasis has now emerged as an important opportunistic disease in patients coinfected with human immunodeficiency virus type-1 (HIV-1). Although the effectiveness of HIV-1 protease inhibitors, such as nelfinavir, in antiretroviral therapies is well documented, little is known of the impact of these drugs on Leishmania in coinfected individuals.


RESULTS
Here, we show that nelfinavir generates oxidative stress in the parasite, leading to altered physiological parameters such as an increase in the sub-G1 DNA content, nuclear DNA fragmentation and loss of mitochondrial potential, which are all characteristics of apoptosis. Pretreatment of axenic amastigotes with the caspase inhibitor z-VAD-fmk did not inhibit the increase in sub-G1 DNA content in nelfinavir-treated parasites, suggesting therefore that this antiviral agent does not kill Leishmania amastigotes in a caspase-dependent manner. Furthermore, we observed that the mitochondrial resident protein endonuclease G is involved. We also demonstrate that parasites overexpressing GSH1 (the rate limiting enzyme of glutathione biosynthesis) were more resistant to nelfinavir when compared to untransfected controls.


CONCLUSIONS
These data suggest that nelfinavir induces oxidative stress in Leishmania amastigotes, culminating in caspase-independent apoptosis, in which DNA is degraded by endonuclease G. This study provides a rationale for future, long-term design of new therapeutic strategies to test nelfinavir as a potential antileishmanial agent as well as for possible future use in Leishmania/HIV-1 coinfections.
Kumar
Pranav
P
Centre de Recherche en Infectiologie, Centre Hospitalier de l'Université Laval, Université Laval, Québec, Canada.
Lodge
Robert
R
Trudel
Nathalie
N
Ouellet
Michel
M
Ouellette
Marc
M
Tremblay
Michel J
MJ
D000818:Animals; D000981:Antiprotozoal Agents / Q000494:pharmacology*; D017209:Apoptosis; D020169:Caspases / Q000378:metabolism; D053938:DNA Fragmentation; D004706:Endodeoxyribonucleases / Q000378:metabolism; D007891:Leishmania / Q000187:drug effects*; D053078:Membrane Potential, Mitochondrial; D019888:Nelfinavir / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects*
D000981:Antiprotozoal Agents; D004706:Endodeoxyribonucleases; C052391:endonuclease G; D020169:Caspases; D019888:Nelfinavir