Identification of Trypanosoma brucei AdoMetDC Inhibitors Using a High-Throughput Mass Spectrometry-Based Assay

Oleg A. Volkov, Casey C. Cosner, Anthony J. Brockway, Martin Kramer, Michael Booker, Shihua Zhong, Ariel Ketcherside, Shuguang Wei, Jamie Longgood, Melissa McCoy, Thomas E. Richardson, Stephen A. Wring, Michael Peel, Jeffrey D. Klinger, Bruce A. Posner, Jef K. De Brabander, Margaret A. Phillips

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Human African trypanosomiasis (HAT) is a fatal infectious disease caused by the eukaryotic pathogen Trypanosoma brucei (Tb). Available treatments are difficult to administer and have significant safety issues. S-Adenosylmethionine decarboxylase (AdoMetDC) is an essential enzyme in the parasite polyamine biosynthetic pathway. Previous attempts to develop TbAdoMetDC inhibitors into anti-HAT therapies failed due to poor brain exposure. Here, we describe a large screening campaign of two small-molecule libraries (∼400,000 compounds) employing a new high-throughput (∼7 s per sample) mass spectrometry-based assay for AdoMetDC activity. As a result of primary screening, followed by hit confirmation and validation, we identified 13 new classes of reversible TbAdoMetDC inhibitors with low-micromolar potency (IC50) against both TbAdoMetDC and T. brucei parasite cells. The majority of these compounds were >10-fold selective against the human enzyme. Importantly, compounds from four classes demonstrated high propensity to cross the blood-brain barrier in a cell monolayer assay. Biochemical analysis demonstrated that compounds from eight classes inhibited intracellular TbAdoMetDC in the parasite, although evidence for a secondary off-target component was also present. The discovery of several new TbAdoMetDC inhibitor chemotypes provides new hits for lead optimization programs aimed to deliver a novel treatment for HAT.

Original languageEnglish (US)
Pages (from-to)512-526
Number of pages15
JournalACS infectious diseases
Issue number7
StatePublished - Jul 14 2017


  • AdoMetDC
  • Trypanosoma brucei
  • high-throughput screening
  • human African trypanosomiasis
  • mass spectrometry

ASJC Scopus subject areas

  • Infectious Diseases


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