INVESTIGADORES
FRACCAROLI Laura Virginia
congresos y reuniones científicas
Título:
Identification of new trypanocidal compounds that inhibit putrescine uptake through in silico screening and in vitro assays
Autor/es:
L. ALBERCA; M. RUIZ; R. DIETRICH; J. MORALES; L. FRACCAROLI; ML. SBARAGLINI; L. GAVERNET; C. CARRILLO; A. TALEVI
Reunión:
Congreso; XXIX Reunión de la Sociedad Argentina de Protozoología; 2017
Resumen:
The polyamines putrescine and spermidine are crucial biomolecules for Trypanosoma cruzi. In contrast with human cells, T. cruzi is incapable of synthesizing polyamines de novo and incorporates them from the extracellular medium. The putrescine permease TcPAT12 has been directly linked to the proliferative ability of T. cruzi, and has been proposed as potential target for the discovery of novel trypanocidal compounds.The aim of this study was the identification of inhibitors of putrescine uptake in T. cruzi. Using ligand-based approximations, in conjunction with a homologymodel of TcPAT12, we have performed an in silico screening to identify TcPAT12 potential inhibitors among existing drugs, a strategy known as drug Repositioning, which allows time- and cost-efficient development of new medications.We compile a database of 256 polyamine analogs that had previously been assayed against T. cruzi. From this dataset, using Dragon molecular descriptors and linear discriminant analysis, we inferred 1000 computational models able to discriminate between inhibitors and non-inhibitors of putrescine transport. The 8 best-performing models were combined through ensemble learning and appliedin the virtual screening of Drug Bank 3.0 database. The probability of being active for the selected compounds was assessed through Positive Predictive Value (PPV) surfaces analysis. Hits with PPV ≥30% we submitted to molecular docking using an in-house homology model of TcPAT12. Two hits were selected for in vitro evaluations: the antiemetic cinnarizine (PPV=50.6%) and the antibiotic clofazimine (PPV=30.0%). Both drugs inhibited putrescine uptake in T. cruzi epimastigotes and interfered with their proliferation with an EC50 of 6.0µM for cinnarizine and 10.6 µM for clofazimine (previously reported). Moreover, both compounds affected trypomastigotes viability.The applied strategy allows identification of potential new drugs with considerable saving of time and material resources.