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Novel compounds for fighting against parasitic diseases

Parasites of the Trypanosomatidae family cause a number of serious human diseases. Researchers from Italy, Belgium, and Germany have published the identification of novel anti-parasitic compounds targeting an enzyme unique to the parasites. These compounds are promising for the development of drugs with fewer side-effects than current medical treatments.

Modena/Brussels/Heidelberg. 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 <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. <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. <www.h-its.org>

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. <www.deduveinstitute.be>

idw :: 04.04.2011