Caracterização de >i<Discrete typing units>/i< (DTUS) utilizando proteômica e ferramentas de bioinformática.

Abstract

OLIVEIRA GS, Characterization of Discrete Typing Units (DTUs) using proteomics and bioinformatics tools. 2017. Masters thesis (Parasitology) -Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, 2017.Chagas disease is one of the most important neglected diseases with an estimated number of 12 million infected individuals, the majority living in Central and South America. The Trypanosoma cruzi (T. cruzi) protozoan parasite is the etiological agent of Chagas' disease. T. cruzi is highly genetically diverse and a new nomenclature separated each strain into seven different genetic groups (TcI-TcVI and Tcbat), named Discrete Typing Units (DTUs) based on their biochemical, immunological and phenotypical characteristics. T. cruzi DTUs have been correlated to diverse clinical outcomes highlighting the importance of molecular epidemiological screens. Despite the development of T. cruzi typing methods based on genetic signatures, each method presents its own advantages and challenges. The work presentedhere shows the application of mass spectrometry for Trypanosoma cruzi Strain Typing Assay using MS 2 peptide spectral libraries (Tc-STAMS 2 ). The novelty of the method is based on the use of peptide fragmentation spectra as strain-specific fingerprints to classify and identify DTUs. Initially, a spectra library is generated from characterized T. cruzi strains. The library is subsequently inspected using MS/MS spectra from unknown strains and confidently assigned to a specific strain in an automated and computationally driven approach. The Tc-STAMS 2 method was employed to test several variables such as sample type and preparation, instrument setup and identification platform. Tc-STAMS 2 provided high confidence and robustness in T. cruzi strain typing. The Tc-STAMS 2 method represents a proof-of-concept of a complementary strategy to the current DNA-based T. cruzi genotyping methods. Moreover, the method allows the identification of strain-specific features that could be related to the biology of T. cruzi strains and their clinical outcomes.