Novel compounds for fighting against parasitic diseases

Trypanosomatid parasites cause diseases like African sleeping sickness, Chagas’ disease and leishmaniasis. Leishmaniasis affects about 12 million people worldwide, mostly in developing countries. Current drug treatments are inadequate due to drug toxicity and resistance.

Now, a group of European scientists has discovered new compounds that may help to fight these diseases more effectively. The project was carried out by research groups headed by Maria Paola Costi (University of Modena and Reggio Emilia, Italy), Rebecca Wade (HITS, Heidelberg Institute for Theoretical Studies, Germany) and Paul Michels (De Duve Institute , Belgium). It was supported by the Cassa di Risparmio di Modena Foundation. The research results have been published in the Journal of Medicinal Chemistry.

Trypanosomatids require folates and biopterins. These are reduced by the enzymes dihydrofolate reductase (DHFR) and pteridine reductase (PTR1). When DHFR is inhibited, DNA replication is impaired, resulting in cell death. However in trypanosomatids, PTR1 is overexpressed when DHFR is inhibited, and PTR1 can take on the role of DHFR by reducing folates, ensuring parasite survival. For the treatment of anti-parasitic diseases, it is thus necessary to block two metabolic pathways by simultaneously inhibiting DHFR and PTR1 by a single drug or a combination of two specific inhibitors. PTR1 is not present in humans and is thus an excellent target for the design of specific compounds that target the parasite.

In this project, the scientists used a virtual screening approach combined with experimental screening methodologies, to identify non-folate-like inhibitors of Leishmania PTR1. Optimization was performed in two rounds of structure-based drug design cycles to improve specificity for PTR1 and selectivity against human DHFR, resulting in 18 drug-like molecules with low micromolar affinities and high in-vitro specificity profiles. Assays of efficacy in cultured Leishmania cells showed six compounds that were active in combination with a DHFR inhibitor. One of these was also effective alone. Several of these compounds showed low toxicity profiles, and one of them is a known drug approved for treatment of diseases of the central nervous system, suggesting potential for label extension of this compound as an anti-parasitic drug candidate.

The original scientific article:
Ferrari et al., Virtual Screening Identification of Nonfolate Compounds, Including a CNS Drug, as Antiparasitic Agents Inhibiting Pteridine Reductase. J. Med. Chem. (2011) 54, 211-221. doi: 10.1021/jm1010572.

http://pubs.acs.org/doi/abs/10.1021/jm1010572

Press Contact
Dr. Peter Saueressig
Public Relations
Heidelberg Institute for Theoretical Studies (HITS)
Phone: +49-6221-533-245
Fax: +49-6221-533-198
peter.saueressig@h-its.org
http://www.h-its.org
Scientific Contacts
Prof. Maria Paola Costi
Dipartimento di Scienze Farmaceutiche,
Universita degli Studi di Modena e Reggio Emilia,
Via Campi 183,
41100 Modena,
Italy
Dr. Rebecca Wade
Molecular and Cellular Modeling Group
Heidelberg Institute for Theoretical Studies (HITS)
Schloss-Wolfsbrunnenweg 35
69118 Heidelberg
Phone: +49 (0)6221 – 533 – 247
Fax: +49 (0)6221 – 533 – 298
rebecca.wade@h-its.org
Prof. Paul Michels
Research Unit for Tropical Diseases,
De Duve Institute and Laboratory of Biochemistry,
Universite catholique de Louvain,
Avenue Hippocrate 74,
B-1200 Brussels,
Belgium
University of Modena and Reggio Emilia (UNIMORE)
UNIMORE is one of the oldest universities in Europe, and currently has more than 20,000 students. Eight of the twelve faculties are located in Modena, among them the Pharmacy faculty with the Department of Pharmaceutical Sciences.

http://www.unimore.it

HITS (Heidelberg Institute for Theoretical Studies)
HITS is a private, non-profit research institute carrying out multidisciplinary research in the computational sciences. It was established in 2010 as a successor to the EML Research. HITS receives its base funding from the Klaus Tschira Foundation, which was established in 1995.

HITS

De Duve Institute, Université catholique de Louvain
The de Duve Institute is a multidisciplinary biomedical research institute hosting several laboratories of the faculty of medicine of UCL (Université catholique de Louvain), as well as the Brussels branch of the Ludwig Institute.

http://www.deduveinstitute.be