Effects of HIV aspartyl-proteinase inhibitors on Leishmania sp.

Ddi1-like protein from Leishmania major is an active aspartyl proteinase

“…DAN, which esterifies the aspartic acids presents in the catalytic center, completely inhibited the activity of the Ddi1-like protein on the three substrates, while pepstatin inhibited 70 % of the activity at 15 μM and NFV inhibited 60 % of the proteolytic activity at 20 μM. The concentration of NFV needed to inhibit the purified recombinant enzyme was slightly more than that reported using a soluble fraction of L. mexicana (Valdivieso et al 2010) and raw extracts from L. amazonensis (Santos et al 2009), although it was similar to that described using the soluble fraction of promastigotes from L. infantum (Valdivieso et al 2010). To our surprise, with a structure containing part of the L. major DDI1-like gene inserted into an S. cerevisiae knockout, White et al (2011a) report an IC 50 of 0.44 μM for NFV.…”

“…These molecules have been identified as promising targets for the development of a rational antileishmanial chemotherapy (Coombs et al 2001;Klemba and Goldberg 2002;Mottram et al 2004;McKerrow et al 2008;McLuskey et al 2010). It is within this context that we reported the presence of aspartyl proteinase activity in promastigotes of Leishmania mexicana and Leishmania infantum (Valdivieso et al 2007(Valdivieso et al , 2010, which is sensitive to diazoacetyl-DL-norleucin methyl ester (DAN) and the specific HIV aspartyl proteinase inhibitors, Ac-Leu-Val-Phenylalaninal, Nelfinavir (NFV), and Saquinavir (Valdivieso et al 2010). Santos et al (2009) also reports the inhibition by NFV and Lopinavir of certain hydrolytic activity from a Leishmania amazonensis extract on an HIV-1 protease substrate, which supports the hypothesis that these drugs have a direct effect on the aspartyl proteinase activity of Leishmania sp.…”

“…Santos et al (2009) also reports the inhibition by NFV and Lopinavir of certain hydrolytic activity from a Leishmania amazonensis extract on an HIV-1 protease substrate, which supports the hypothesis that these drugs have a direct effect on the aspartyl proteinase activity of Leishmania sp. In addition, we found that in the presence of aspartyl proteinase inhibitors, promastigotes and amastigotes of L. mexicana and L. infantum show antiproliferative activity with a significant percentage of binucleate cells, and in some cases multinucleate cells, indicating a blockage of cytokinesis (Valdivieso et al 2007(Valdivieso et al , 2010, and reiterating the importance of aspartyl proteinase activity for the survival of these trypanosomatids. To date, two aspartyl proteinase genes have been identified within the genome of Leishmania sp.…”

“…The presence of aspartyl proteinases in protozoa from the Trypanosomatidae family was only postulated less than a decade ago (Valdivieso et al 2007;Pinho et al 2009;Santos et al 2009), leading to the suggestion that they may play a role in the proliferation of the Leishmania parasites (Valdivieso et al 2007;Santos et al 2009;Valdivieso et al 2010;White et al 2011a). In the present study, we cloned the full L. major sequence of a molecule that belongs to a Leishmania family of proteins that include an active RP domain, characteristic of the aspartyl proteases from the family A 2 .…”

“…Previous studies have shown that selective aspartyl proteinase inhibitors inhibited the proliferation of Leishmania sp. promastigotes and amastigotes in vitro, possibly in cytokinesis (Valdivieso et al 2010). These observations would fit in with a possible role that the protein we have now cloned may play in the regulation of the cell cycle of the parasite, either in the marking of proteins with ubiquitin or in the control of the cell cycle, particularly those that occur in the metaphase-to-anaphase transition or those that occur at the end of mitosis.…”