Thiazolidinone-Related Heterocyclic Compounds as Potential Antitrypanosomal Agents

Human African trypanosomiasis (HAT) and Chagas disease are neglected tropical diseases (NTDs) due to parasite protists from the Trypanosoma genus transmitted by insect vectors. Trypanosomiases affect mostly poor populations in the developing countries, and the development of new antitrypanosomal drugs is underinvested by governments and the pharmaceutical industry. In this chapter, we described the development of 4-thiazolidinone and thiazole derivatives with heterocyclic fragments which exhibit good inhibition of trypanosome growth and might constitute potential candidates for the development of new drugs against trypanosomiasis. Antitrypanosomal design, mainly within structure-based design, led to the synthesis of 5-ene-4-thiazolidinone-3-alkanecarboxylic acids; 2,3-disubstituted 4-thiazolidinones; thiazolidinone-pyrazoline, phenylindole-thiazolidinone, and imidazothiadiazole-thiazolidinone hybrids; as well as 4-thiazolidinone-based fused heterocycles, especially thiopyrano[2,3-d]thiazoles, and non-thiazolidinone compounds–namely, isothiocoumarine derivatives. Moreover, antitrypanosomal 4-thiazolidinones are of special interest in the search for new antimalarial and antileishmanial agents. Also many active anticancer agents among the abovementioned 4-thiazolidinones have been discovered

Estudo funcional da prolil oligopeptidase de Trypanosoma cruzi e Leishmania infantum : nocaute gênico, inibição enzimática e processos infectivos

Tese (doutorado)—Universidade de Brasília, Faculdade de Medicina, Programa de Pós-Graduação em Patologia Molecular, 2018.A prolil oligopeptidase (POP) é uma serino protease que cliva peptídeos de até 30 aminoácidos, porém já foi observada sua capacidade de hidrólise de colágeno, fibronectina e componentes da matriz extracelular. Participa de importantes processos biológicos e está envolvida em diversas doenças neurológicas e inflamatórias. Estudo recentes apontaram a POP de Trypanosoma cruzi (POPTc80) como importante alvo contra a doença de Chagas por meio do desenvolvimento de vacina contra a proteína. Este trabalho teve como objetivo analisar o envolvimento da POP na patogenia de duas doenças: a doença de Chagas e a Leishmaniose visceral. A prolil oligopeptidase de T. cruzi (POPTc80) foi analisada por meio de nocaute físico do gene POPTC80 com a deleção do alelo Non-esmeraldo like pela integração do cassete contendo o gene NEO, que confere resistência a geneticina (G418), sendo observado diferenças de expressão da proteína tanto entre os diferentes clones quanto comparado a cultura selvagem. O clone B2 apresentou uma divisão celular a cada 47 h e o clone C6 a cada 52h, e a imuno marcação mostrou uma redução na intensidade do sinal de fluorescência. O nocaute do alelo Esmeraldo-like para realizar o duplo nocaute, foi com reparo por homologia direta (RHD) e inserção do cassete que confere resistência a marca de seleção higromicina. O duplo nocaute (poptc80-/-) foi confirmado pela amplificação do gene higromicina fosfotransferase e corroborado pela imunofluorescência (IF) com ausência de marcação da POPTc80 nos parasitos. A POP de L. infantum (POPLi) foi avaliada quanto a sua capacidade infectiva em macrófagos murinos sob presença de inibidores específicos da POP, S 17092 e Z-Pro-Prolinal, indicando 50% de redução da taxa de infecção, o que também foi observado quando os parasitos foram incubados com a proteína recombinante e o anticorpo. A POPLi foi observada expressa na fração de membrana e citoplasmática do parasito e este resultado foi corroborado pelo ensaio de IF. A análise funcional da POP de T. cruzi e L. infantum, nos permite avançar na busca por novos alvos quimioterápicos para o tratamento de ambas as doenças tropicais negligenciadas.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Prolyl oligopeptidase (POP) is a serine protease that cleaves peptides of up to 30 amino acids, but its ability to hydrolyze collagen, fibronectin and extracellular matrix components has already been observed. It participates in important biological processes and is involved in several neurological and inflammatory diseases. Recent studies have pointed to POP of Trypanosoma cruzi (POPTc80) as an important target against Chagas' disease through the development of a vaccine against the protein. This work aimed to analyze the involvement of POP in the pathogenesis of two diseases: Chagas disease and visceral leishmaniasis. The T. cruzi prolyl oligopeptidase (POPTc80) was analyzed by physical knockout of the POPTC80 gene with the deletion of the Non-Esmerald allele allele by the integration of the NEO gene-containing cassette that confers resistance to geneticin (G418), with differences expression of the protein both among the different clones and compared to the wild type. Clone B2 showed a cell division every 47 h and clone C6 every 52 h, and immunoblotting showed a reduction in fluorescence signal intensity. The knockout of the Esmeraldo-like allele to perform the double knockout was with direct homology repair (RHD) and insertion of the cassette that confers resistance to the hygromycin selection marker. The double knockout (poptc80 - / -) was confirmed by amplification of the hygromycin phosphotransferase gene and corroborated by immunofluorescence (IF) with no labeling of POPTc80 in the parasites. The POP of L. infantum (POPLi) was evaluated for its infective capacity in murine macrophages in the presence of specific inhibitors of POP, S 17092 and Z-Pro-Prolinal, indicating a 50% reduction in infection rate, which was also observed when the parasites were incubated with the recombinant protein and the antibody. POPLi was observed expressed in the membrane and cytoplasmic fraction of the parasite and this result was corroborated by the IF assay. The functional analysis of the POP of T. cruzi and L. infantum allows us to advance in the search for new chemotherapeutic targets for the treatment of both neglected tropical diseases

Molecular characterisation of metacaspase 5 and the production of oligopeptidase b-specific single chain variable fragment antibodies for potential animal African trypanosomosis chemotherapies and diagnostics.

Doctor of Philosophy in Biochemistry. University of KwaZulu-Natal, Pietermaritzburg, 2018.African trypanosomosis (AT) is a major obstacle in the establishment of agriculture and economic sustainability in Africa. Animal AT is responsible for large numbers of livestock succumbing to the tsetse transmitted kinetoplastid parasites, Trypanosoma congolense and T. vivax, and as a result, losses in further downstream sectors are experienced. Due to the ability of the trypanosomal parasites to undergo antigenic variation, vaccine candidates are highly unlikely. Peptidases have been identified as virulence factors and are the focus of the development of novel chemotherapies and diagnostics. The metacaspases (MCAs) are a prime example of a chemotherapeutic target and oligopeptidase B (OPB), that of a diagnostic target. Towards the validation of a chemotherapeutic target, recombinant expression was used to obtain an active peptidase which could be enzymatically characterised. Various inhibitors were investigated and their effect on the parasite, analysed. Current diagnostics are based on antibody detection, but an antigen detection format would be preferable as it could differentiate between active and cured infections as anti-trypanosomal antibodies can persist for years. Given the rural, resource-poor locations in the areas of AT incidence, an ideal rapid diagnostic test (RDT) would be robust, affordable, sensitive and specific and requiring minimal training, such as a dipstick test. The MCAs are cysteine peptidases which are found in all kingdoms other than the metazoa, and share a secondary structure fold and catalytic dyad with the metazoan caspases. Since the caspases play a role in apoptosis, it is thought that the MCAs may function in a similar manner. The single copy MCAs of Trypanosoma spp. and Leishmania spp. differ from the multicopy MCAs in that they possess a Pro-, Gln-, Tyr-rich C-terminal domain which is thought to mediate protein-protein interactions. The activity of the single copy MCAs from T. cruzi and L. major has been implicated in the cell cycle of the kinetoplastid parasite. The aim of the project was to express, purify and enzymatically characterise the recombinant and native MCA5 from T. congolense and T. vivax. Using the 3D structures, solved by X-ray diffraction, of MCA2 from T. b. brucei, molecular docking studies were used to validate the inhibition potential of a published library of inhibitors, designed based on the, then, hypothetical structure of TbbMCA2. Since the elucidation of the 3D structure of TbbMCA2 by X-ray diffraction, the inhibitory power of the library of inhibitors against TbbMCA2 and the MCA5s was investigated. The serine peptidase, OPB, has been shown to be released into the host bloodstream by dead and dying parasites. The use of phage displayed scFv (single chain fragment variable) antibodies for the detection of OPB in serum from infected cattle is reported, towards the development of a RDT. Recombinantly expressed TcoMCA5 was shown to autoprocess and over autoprocess when purified using nickel affinity chromatography. Mutagenesis of the catalytic dyad residues reduced the over autoprocessing and the mutated form was enzymatically active at a pH between 6 and 9. This active mutant and purified TcoMCA5 showed a prefence for Arg over Lys at the P1 substrate position and were able to hydrolyse gelatin. Possible novel inhibitors of TbbMCA2 and the MCA5s of T. congolense and T. vivax were identified using a library of ligands (Berg library) based on the P1 specificity of TbbMCA2 and molecular docking. Commercial fluorogenic peptide substrates and inhibitors reported in literature for the characterisation of various MCAs, revealed interactions with the MCAs which should be taken into consideration when modifying the Berg ligands to achieve higher affinity for the MCAs. The application of scFv antibodies, derived from the Nkuku® phagemid library, for the diagnosis of current AAT infections by the detection of OPB, released in the bloodstream of the infected mammalian host, was investigated. After the successful isolation and production of OPB-specific scFv, MCA-specific scFv antibodies can be pursued using the Nkuku® phagemid library. The resulting OPB-specific scFv identified a conserved peptide between T. congolense and T. vivax and was able to detect native OPB in a western blot format. It was predicted that the scFv interacted with OPB in such a way that it would restrict the hinge motion between the C-terminal catalytic and N-terminal regulatory domains of the enzyme and limit access to the active site pocket. The ability of scFv and rabbit-anti-OPB polyclonal antibody in an antigen detection ELISA with sera from T. congolense infected cattle indicated that detection of OPB fluctuated with parasitaemia

Caracterização de mutantes de Trypanosoma cruzi deficientes em dipeptidil peptidase 8 e produção de anticorpos contra proteínas ligadoras de RNA (UBP1Tc e UBP2Tc)

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Medicina, Programa de Pós-Graduação em Patologia Molecular, 2019.A doença de Chagas é uma patologia crônica, causada pelo protozoário Trypanosoma cruzi, endêmica em países da América Latina. Entretanto, possui impacto mundial uma vez que estudos econômicos indicam um custo de 7,2 bilhões de dólares por ano associado a doença. O medicamento disponível para seu combate, benzonidazol, apresenta baixa eficácia em fase crônica e a grande complexidade biológica do organismo dificulta o desenvolvimento de novos fármacos. Portanto, se faz necessário o melhor entendimento do tripanossomatídeo, assim como das moléculas envolvidas nos seus processos celulares. Nesse aspecto se sobressaem a dipeptidil peptidase 8 (DPP8Tc), que ainda não possui sua função biológica conhecida, mas apresenta homólogos com papel importante em diversas patologias, e as proteínas ligadoras de RNA (UBP1Tc e UBP2Tc), por sua atuação na regulação da expressão gênica. O presente trabalho almejou contribuir com a elucidação da função da DPP8Tc e produzir ferramentas para estudos posteriores sobre as RPBs. Linhagens de T. cruzi simples nocaute para o gene dpp8tc foram caracterizadas, sendo observado uma diminuição na taxa de metaciclogênese do clone F9, que apresentou a menor expressão da proteína vista por western blot e imunofluorescência. Ensaios de metabolômica mostraram uma maior produção de prolina intracelular no clone C8, e o estudo da expressão de outras proteases permitiu se constatar uma superexpressão de enzimas da mesma família (POPTc80, OPBTc) nos mutantes simples. Além disso, as formas tripomastigotas metacíclicas selvagens apresentaram menor expressão da DPP8Tc em relação as formas epimastigotas. Em conjunto, esses dados indicam um possível papel dessa enzima no processo de diferenciação. A tentativa de duplo nocaute foi realizada por meio da técnica de CRISPR-Cas9, ainda que este não pôde ser confirmado. Ademais, as RBPs, UBP1Tc e UBP2Tc foram expressas de forma heteróloga, e anticorpos policlonais foram produzidos para essas proteínas. Esses anticorpos serão importantes ferramentas de validação para estudos proteômicos da interação entre RBPs e RNAs.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Fundação de Apoio à Pesquisa do Distrito Federal (FAP/DF); Fundação de Apoio para Pesquisa, Ensino, Extensão e Desenvolvimento Institucional (FINATEC) e COFECUB.Chagas disease is a chronic pathology, caused by the protozoan Trypanosoma cruzi, and is endemic in Latin American countries. However, it has a worldwide impact, since economic studies indicate an annually cost of 7.2 billion of dollars associated with the disease. Its available treatment, benznidazole, has low efficacy in the chronic phase, and the great biological complexity of the organism hinders the development of new drugs. Therefore, it is necessary to have a better understanding of the trypanosomatid, as well as the molecules involved in their cellular processes. In this aspect are highlighted the dipeptidyl peptidase 8 (DPP8Tc), which does not have its biological function known, but presents homologues with important role in several pathologies, and the RNA-binding proteins (UBP1Tc e UBP2Tc) for their performance in the regulation of gene expression. The present work aimed to contribute to the elucidation of DPP8Tc function and to produce tools for further studies on RPBs. T. cruzi single knockouts for the dpp8tc gene were characterized, with a decrease in the metacyclogenesis rate of clone F9, which also showed the lowest expression of the protein seen by western blot and immunofluorescence. Metabolomic assays showed higher production of intracellular proline in clone C8, and the study of the expression of other proteases revealed an overexpression of enzymes of the same family (POPTc80, OPBTc) in the single mutants. In addition, wild type metacyclic trypomastigote forms showed lower expression of DPP8Tc in relation to epimastigote forms. Together, these results indicate a possible role of this enzyme in the differentiation process. The double knockout attempt was performed using the CRISPR-Cas9 technique, although this could not be confirmed. In addition, the RBPs, UBP1Tc and UBP2Tc were expressed in procariote system, and polyclonal antibodies were produced for these proteins. These antibodies will be important validation tools for proteomic studies of the interaction between RBPs and RNAs

Stevia Genus: Phytochemistry and Biological Activities Update

The Stevia genus (Asteraceae) comprises around 230 species, distributed from the southern United States to the South American Andean region. Stevia rebaudiana, a Paraguayan herb that produces an intensely sweet diterpene glycoside called stevioside, is the most relevant member of this genus. Apart from S. rebaudiana, many other species belonging to the Stevia genus are considered medicinal and have been popularly used to treat different ailments. The members from this genus produce sesquiterpene lactones, diterpenes, longipinanes, and flavonoids as the main types of phytochemicals. Many pharmacological activities have been described for Stevia extracts and isolated compounds, antioxidant, antiparasitic, antiviral, anti-inflammatory, and antiproliferative activities being the most frequently mentioned. This review aims to present an update of the Stevia genus covering ethnobotanical aspects and traditional uses, phytochemistry, and biological activities of the extracts and isolated compounds.Fil: Borgo, Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Laurella, Laura Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Martini, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Catalán, Cesar A. N.. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Orgánica; ArgentinaFil: Sülsen, Valeria Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; Argentin

The development of thiosulfonates as cysteine protease inhibitors

Cysteine proteases are ubiquitous throughout nature as proteolytic machinery that are responsible for key physiological processes. Unregulated, uncontrolled or undesired proteolysis is often a key process in many disease states. As such, specific inhibitors of cysteine proteases offer a unique therapeutic target for chemotherapeutic intervention. This is particularly true in many diseases caused by parasitic infections, such as Malaria, Schistosomiasis and Chagas disease, as the parasitic lifecycle is often highly dependent upon cysteine proteases. The majority of attempts at conferring specificity of covalent inhibitors have been derived from classical structure activity relationship (SAR) studies. Such studies place emphasis on the primary non-covalent interaction with little optimisation of the electrophillic trap, which forms the covalent bond, being attempted. In this work a new class of electrophillic traps, the thiosulfonates, will be developed as cysteine protease inhibitors. This aims to take advantage of the differing chemistry observed for cysteine proteases, with a sulfur centred nucleophile, rather than the oxygen centred nucleophile which is present in all other protease classes. When combined with classical SAR this two pronged attack should greatly increase inhibitor specificity and reduce off target effects, adding to the chemical toolkit available to medicinal chemists. Throughout this work the synthesis, reactivity profiles and biological evaluation of thiosulfonates as cysteine protease inhibitors will be explored. Computational modelling studies will be incorporated, highlighting the synergy between classical SAR and electrophilic trap optimisation. This will culminate in the application of thiosulfonates towards schistosomiasis, the second biggest neglected tropical disease after malaria

Synthesis and evaluation of antichlamydial, antileishmanial and antimalarial activity of benzimidazole and benzoxadiazole derivatives

The aim of this thesis was to synthesize 1H-benz[d]imidazole- and benzo[c][1,2,5]oxadiazole-derived compounds active against intracellular bacterium Chlamydia pneumoniae and protozoan parasites Leishmania donovani, and Plasmodium falciparum, and to find new potent compounds as hit molecules for further development. A number of issues dictate the importance of the pursuit of this work. First, C. pneumoniae contributes to human health by being a widespread bacterium and causing respiratory infections such as pneumonia. In addition, atherosclerosis has been shown to be connected to the bacterium s persistent form. Second, a neglected tropical disease, visceral leishmaniasis in turn is caused by a protozoan parasite L. donovani and can be fatal if left untreated. Its current treatments suffer from toxicity, poor compliance and prevalent parasite resistance. Third, another tropical disease, malaria is caused by protozoan parasites belonging to the genus Plasmodium. P. falciparum resistance to recent antimalarial drugs is an ever growing and alarming issue, and there is an unmet medical need for new antimalarial chemotypes targeting the different parasite forms present in various stages of the Plasmodium life cycle. Heterocyclic chemical structures are widely used in the early drug discovery process and in compound screening. At the outset of this study, a series of 2-arylbenzimidazole derivatives was designed to target C. pneumoniae and L. donovani. Further development of these 2-arylbenzimidazoles resulted in a set of 2-aminobenzimidazoles against P. falciparum. Benzoxadiazole derivatives were designed against L. donovani. Facile and general synthesis routes for the preparation of both benzimidazole and benzoxadiazole derivatives were developed. In order to study structure-activity relationships of the antichlamydial and antileishmanial 2-arylbenzimidazoles, the left, right and central parts of the core molecular structure were modified and different substitution patterns were employed. Antichlamydial, antileishmanial and antimalarial inhibition activities were related to the different structural modifications carried out. Antichlamydial and antileishmanial 2-arylbenzimidazoles or benzoxadiazole derivatives inhibited target pathogens at the micromolar level. Furthermore, 2-aminobenzimidazoles were studied as antimalarial compounds. The best derivative from this study inhibits growth of P. falciparum (IC50 94 nM) and has a good pharmacokinetic profile. The compound turned out to be efficacious in vivo against P. falciparum upon once a day oral administration. In this study, selectivity of the 2-arylbenzimidazoles against selected intracellular parasites over free living (planktonic) pathogens e.g.Escherichia coli was observed. This is a great advantage from the antimicrobial drug discovery point of view. In spite of the mechanisms of action of the studied derivatives remaining elusive, it was possible to show in this study that antimicrobial compound design can be successful even in the case of unknown macromolecular targets of C. pneumoniae, L. donovani, and P. falciparum.Tämän väitöskirjatyön tarkoituksena oli syntetisoida bentimidatsoli ja bentsoksadiatsoli johdannaisia kolmea solunsisäistä patogeeniä vastaan, ja löytää uusia lupaavia yhdisteitä jatkotutkimusta varten. Ensimmäinen kohdebakteeri on Chlamydia pneumoniae, joka on maailmanlaajuinen hengitystieinfektioita, kuten keuhkokuumetta, aiheuttava bakteeri. Lisäksi tämän bakteerin krooninen muoto on liitetty mm. ateroskleroosiin. Toinen kohdeloinen on L. donovani, joka aiheuttaa hoitamattomana kuolemaan johtavaa sisäelin leismaniaasia. Nykyisten leismaniaasin vastaisten lääkkeiden ongelmia ovat toksisuus, huono hoitomyöntyvyys ja loisten resistenssi lääkkeitä kohtaan. Kolmas työn kohdeloinen on Plasmodium falciparum. Tätä malariaa aiheuttavaa loista vastaan tarvittaisiin kipeästi uusia lääkeaineita, koska resistenssi malarialääkkeitä vastaan leviää, ja loisen eri elinkierron vaiheisiin ei ole vielä saatavilla kattavasti lääkkeitä. Heterosykliset kemialliset rakenteet, kuten bentsimidatsolit ja bentoksadiatsolit, ovat laajasti käytössä lääkkeiden tutkimus- ja kehitysprosesseissa. Tämä työ perustuu ryhmämme aikaisempaan näitä heterosyklisiä rakenteita koskevaan tutkimukseen. Tutkimuksen alkuvaiheessa suunniteltiin ja syntetisoitiin joukko 2-aryylibentsimidatsolijohdannaisia C. pneumoniaa ja L. donovania vastaan. Myöhempi näiden yhdisteiden jatkokehitys johti 2-aminobentsimidatsolien tutkimukseen P. faliparumia vastaan. Malariaan liittyvä väitöskirjatutkimuksen osa-aluea tehtiin Open Lab projektina Espanjassa GlaxoSmithKlinen kanssa yhteistyössä. Bentsoksadiatsoleita taas suunniteltiin ja syntetisoitiin L. donovania vastaan. Kaikille yhdistejoukoille kehitettiin toimivat ja käytännölliset synteesireitit tässä väitöskirja työssä, biologiset testaukset puolestaan tehtiin yhteistyökumppanien toimesta. Tutkimuksen tärkeä osa-alue oli rakenne-aktiivisuussuhteiden tarkastelu. Syntetisoimalla johdannaisia, joiden eriosia muokattiin tai päärakenteeseen liitettiin erilaisia substituentteja, havaittiin, että klamydian, leishmaniaasin ja malarian vastaisilla yhdisteillä eri rakenteet vaikuttivat nostavasti aktiivisuuteen. 2-Aryylibentsimidatsolit inhiboivat yleisesti ottaen kohde patogeenien kasvua mikromolaarisilla konsentraatioilla. Tässä tutkimuksessa havaittiin myös 2-aryylibentsimidatsolijohdannaisten selektiivisyys tutkittuja solunsisäisiä patogeenejä vastaan, koska yhdisteet eivät esimerkiksi estäneet tutkittujen vapaiden bakteerien, kuten E. colin, kasvua. 2-Aminobentsimidatsolit malarian vastaisina yhdisteinä olivat tutkimuksen lupaavimpia yhdisteitä. Koska suunnitellulla ja syntetisoidulla aktiivisimmalla yhdisteellä oli hyvät farmakokineettiset ominaisuudet, sen aktiivisuus testattiin eläinkokeessa P.falciparum -infektoiduilla hiirillä. Tämä yhdiste poisti malarialoiset hiiriltä suun kautta annosteltuna kerran päivässä kahden antokerran aikana. Kuitenkin alentunut aktiivisuus resistenttejä kantoja vastaan sekä mahdollinen sydäntoksisuus ovat riskitekijöitä jatko-tutkimukselle. Johdannaisten vaikutusmekanismeja ja kohdeproteiineja ei tiedetä, mutta silti tässä väitöskirjatyössä pystyttiin menestyksekkäästi suunnittelemaan, syntetisoimaan ja löytämään uusia yhdisteitä C. pneumonia -bakteeria, L. donovani ja P. falciparumia -loisia vastaan

Búsqueda y optimización de potenciales alternativas terapéuticas para el tratamiento de la enfermedad de chagas

La enfermedad de Chagas, causada por Trypanosoma cruzi, es una parasitosis endémica en 21 países de América Latina, donde se transmite por las heces contaminadas de triatominos, provoca más de 7.000 muertes anuales y cerca de 25 millones de personas están en riesgo de contraer la infección. Clasificada por la OMS como una de las 17 enfermedades tropicales desatendidas, principalmente se extiende entre la población más desfavorecida de las zonas rurales. Sin embargo, vías de trasmisión alternativas como la transfusional o la congénita, y los movimientos migratorios, han hecho de ella una enfermedad emergente en países como EE.UU, Australia o España, afectando a más de 7 millones de personas en el mundo. La fase aguda aparece una semana tras la infección y posee baja mortalidad (<10%), asociada a fallo cardíaco y/o meningoencefalitis. En la mayoría de los casos es asintomática u oligosintomática y se resuelve espontáneamente. Tras 12 meses, la respuesta inmune controla parcialmente la infección y aunque no la erradica, el 6070% de los pacientes nunca la manifiesta (fase indeterminada). El 3040% restante entra en fase crónica durante los 1030 años posteriores, con afectación cardíaca y/o digestiva (megaesófago y megacolon). Después de más de un siglo desde su descubrimiento, no se dispone de fármacos adecuados para su tratamiento, basado en dos nitroderivados introducidos hace más de 40 años: benznidazol (BZ) y nifurtimox, recomendados para tratar los casos agudos y crónicos recientes, pero con actividad limitada en la fase crónica avanzada. Su controvertida eficacia, elevada toxicidad y la aparición de cepas de T. cruzi resistentes, afecta al éxito de estas terapias..