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Using a Non-Image-Based Medium-Throughput Assay for Screening Compounds Targeting N-myristoylation in Intracellular Leishmania Amastigotes

We have refined a medium-throughput assay to screen hit compounds for activity against N-myristoylation in intracellular amastigotes of Leishmania donovani. Using clinically-relevant stages of wild type parasites and an Alamar blue-based detection method, parasite survival following drug treatment o...

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Detalles Bibliográficos
Autores principales: Paape, Daniel, Bell, Andrew S., Heal, William P., Hutton, Jennie A., Leatherbarrow, Robin J., Tate, Edward W., Smith, Deborah F.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4270692/
https://www.ncbi.nlm.nih.gov/pubmed/25522361
http://dx.doi.org/10.1371/journal.pntd.0003363
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author Paape, Daniel
Bell, Andrew S.
Heal, William P.
Hutton, Jennie A.
Leatherbarrow, Robin J.
Tate, Edward W.
Smith, Deborah F.
author_facet Paape, Daniel
Bell, Andrew S.
Heal, William P.
Hutton, Jennie A.
Leatherbarrow, Robin J.
Tate, Edward W.
Smith, Deborah F.
author_sort Paape, Daniel
collection PubMed
description We have refined a medium-throughput assay to screen hit compounds for activity against N-myristoylation in intracellular amastigotes of Leishmania donovani. Using clinically-relevant stages of wild type parasites and an Alamar blue-based detection method, parasite survival following drug treatment of infected macrophages is monitored after macrophage lysis and transformation of freed amastigotes into replicative extracellular promastigotes. The latter transformation step is essential to amplify the signal for determination of parasite burden, a factor dependent on equivalent proliferation rate between samples. Validation of the assay has been achieved using the anti-leishmanial gold standard drugs, amphotericin B and miltefosine, with EC(50) values correlating well with published values. This assay has been used, in parallel with enzyme activity data and direct assay on isolated extracellular amastigotes, to test lead-like and hit-like inhibitors of Leishmania N-myristoyl transferase (NMT). These were derived both from validated in vivo inhibitors of Trypanosoma brucei NMT and a recent high-throughput screen against L. donovani NMT. Despite being a potent inhibitor of L. donovani NMT, the activity of the lead T. brucei NMT inhibitor (DDD85646) against L. donovani amastigotes is relatively poor. Encouragingly, analogues of DDD85646 show improved translation of enzyme to cellular activity. In testing the high-throughput L. donovani hits, we observed macrophage cytotoxicity with compounds from two of the four NMT-selective series identified, while all four series displayed low enzyme to cellular translation, also seen here with the T. brucei NMT inhibitors. Improvements in potency and physicochemical properties will be required to deliver attractive lead-like Leishmania NMT inhibitors.
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spelling pubmed-42706922014-12-26 Using a Non-Image-Based Medium-Throughput Assay for Screening Compounds Targeting N-myristoylation in Intracellular Leishmania Amastigotes Paape, Daniel Bell, Andrew S. Heal, William P. Hutton, Jennie A. Leatherbarrow, Robin J. Tate, Edward W. Smith, Deborah F. PLoS Negl Trop Dis Research Article We have refined a medium-throughput assay to screen hit compounds for activity against N-myristoylation in intracellular amastigotes of Leishmania donovani. Using clinically-relevant stages of wild type parasites and an Alamar blue-based detection method, parasite survival following drug treatment of infected macrophages is monitored after macrophage lysis and transformation of freed amastigotes into replicative extracellular promastigotes. The latter transformation step is essential to amplify the signal for determination of parasite burden, a factor dependent on equivalent proliferation rate between samples. Validation of the assay has been achieved using the anti-leishmanial gold standard drugs, amphotericin B and miltefosine, with EC(50) values correlating well with published values. This assay has been used, in parallel with enzyme activity data and direct assay on isolated extracellular amastigotes, to test lead-like and hit-like inhibitors of Leishmania N-myristoyl transferase (NMT). These were derived both from validated in vivo inhibitors of Trypanosoma brucei NMT and a recent high-throughput screen against L. donovani NMT. Despite being a potent inhibitor of L. donovani NMT, the activity of the lead T. brucei NMT inhibitor (DDD85646) against L. donovani amastigotes is relatively poor. Encouragingly, analogues of DDD85646 show improved translation of enzyme to cellular activity. In testing the high-throughput L. donovani hits, we observed macrophage cytotoxicity with compounds from two of the four NMT-selective series identified, while all four series displayed low enzyme to cellular translation, also seen here with the T. brucei NMT inhibitors. Improvements in potency and physicochemical properties will be required to deliver attractive lead-like Leishmania NMT inhibitors. Public Library of Science 2014-12-18 /pmc/articles/PMC4270692/ /pubmed/25522361 http://dx.doi.org/10.1371/journal.pntd.0003363 Text en © 2014 Paape et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Paape, Daniel
Bell, Andrew S.
Heal, William P.
Hutton, Jennie A.
Leatherbarrow, Robin J.
Tate, Edward W.
Smith, Deborah F.
Using a Non-Image-Based Medium-Throughput Assay for Screening Compounds Targeting N-myristoylation in Intracellular Leishmania Amastigotes
title Using a Non-Image-Based Medium-Throughput Assay for Screening Compounds Targeting N-myristoylation in Intracellular Leishmania Amastigotes
title_full Using a Non-Image-Based Medium-Throughput Assay for Screening Compounds Targeting N-myristoylation in Intracellular Leishmania Amastigotes
title_fullStr Using a Non-Image-Based Medium-Throughput Assay for Screening Compounds Targeting N-myristoylation in Intracellular Leishmania Amastigotes
title_full_unstemmed Using a Non-Image-Based Medium-Throughput Assay for Screening Compounds Targeting N-myristoylation in Intracellular Leishmania Amastigotes
title_short Using a Non-Image-Based Medium-Throughput Assay for Screening Compounds Targeting N-myristoylation in Intracellular Leishmania Amastigotes
title_sort using a non-image-based medium-throughput assay for screening compounds targeting n-myristoylation in intracellular leishmania amastigotes
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4270692/
https://www.ncbi.nlm.nih.gov/pubmed/25522361
http://dx.doi.org/10.1371/journal.pntd.0003363
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