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Production and characterisation of synthetic inhibitors of parasite ofproteases as drug candidates for the predominant protozoal diseases SouthAmerica and other developing regions


To develop specific inhibitors of parasitic cysteine proteases as drug candidates for the treatment of the predominant protozoal diseases (in particular Leishmaniasis and Chagas disease) of South America and other developing countries. This goal will be attained through the implementation of molecular biology, enzymology and state of the art combinatorial chemical library techniques.
Expected Outcome

Since the chemotherapeutic treatment of parasitic diseases is not satisfactory because of drug toxicity and the development of drug resistant parasites, the development of alternative drugs is of grave import. By the end of this project, we will have developed a new class of antiparasitic drugs. Simultaneously, we will have deepened the understanding of the mechanism and specificity of CPs and the mode of action of various parasites. Moreover, we will have established a multidisciplinary, international research network to foster innovations in the drug discovery approach.
Solid phase chemical synthetic methodology will be developed simultaneously with molecular and recombinant technology which will generate large quantities of cysteine proteases for screening. An iterative process of screening and optimization will lead to the target drug candidates. The measurable objectives are outlined as follows in quasi-chronological order.

* The development of resins suitable for both synthesis of non-peptide inhibitor libraries as well as solid fluorescent-quenched enzymatic assays.
* The isolation of recombinant and native Leishmania cysteine proteases (CPs) in large amounts.
* The determination of substrate specificity of recombinant cruzipain and important Leishmania CPs using substrate libraries and MS detection.
* The development of several methods (nanoprobe MAS-NMR of single beads, MS-MS, and ladder synthesis/MS) for the fast and efficient analysis of resin-bound peptide substrates and non-peptide inhibitors.
* The development of solid phase synthetic methodologies for the rapid generation of potent and selective CP inhibitors.
* The construction of a novel syntheziser for manual organic library synthesis with the capacity to provide inert reaction conditions, for temperature control and for refluxing conditions.
* The screening of substrate and inhibitor libraries with T. cruzi and Leishmania CPs and the detection of potent inhibitors.
* The synthesis of inhibitors in larger quantities and an analysis of their activity towards pure CPs. The selectivity of the inhibitors will be assessed by comparison with mammalian cathepsins B and L.
* The testing of inhibitors for antiparasite activity in vitro and in vivo.
* The application of gene knockout and over-expression of CPs in L. mexicana and subsequent transfer of that methodology to other Leishmania species in order to identify and characterize key CPs and to produce recombinant enzymes for use in drug development.

Another important aspect of this project is the transfer of knowledge and techniques required for synthesis and enzymatic assays of chemical libraries and methods of reverse gene technology to partners in developing countries. The transfer will partly be established by training visits in the EU-based laboratories. In addition, a multidisciplinary research network in LA-EEC will be established to foster the development of the field of drug leads and design using an interdisciplinary approach involving state-of-the-art molecular and biochemical techniques and combinatorial chemistry.

Funding Scheme

CSC - Cost-sharing contracts


10,Gamle Carlsberg Vej 10
2500 Valby

Participants (4)

Escola Paulista de Medicina
100,Rua Trés De Maio
04044-020 Sao Paulo
Fundaéo Bio Rio
S/n,ilha Do Fundéo
21944 Rio De Janeiro
United Kingdom
University Avenue
Universidad Peruana Cayetano Heredia
430,Avenida Honorio Delgrado
4314 Lima