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| Author(s): |
Eduardo Seiji Yamamoto
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD) |
| Defense date: | 2019-04-26 |
| Examining board members: |
Luiz Felipe Domingues Passero;
Marcia Dalastra Laurenti;
José Angelo Lauletta Lindoso;
Marcia Aparecida Sperança
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| Advisor: | Luiz Felipe Domingues Passero |
| Abstract | |
Leishmaniosis is a neglected disease caused by parasitic protozoa belonging to the genus Leishmania sp. and transmitted by vectors. This disease presents different clinical forms ranging from single lesion, that can heal spontaneously, to the visceral form, that affects the spleen, liver, bone marrow and lymph nodes, and may lead to death if not properly treated. Additionally, according to the World Health Organization, leishmaniosis is endemic to 98 countries. The treatment is still carried out with two main drugs, antimonials and amphotericin B that induce side effects; in addition, reports about the emergence of parasite resistance have been published. Besides, alternative drugs such as miltefosine and pentamidine still have serious side effects and are not always effective to treat all Leishmania species and/or clinical form. In this regard, drug repurposing has been considered an important strategy to develop new therapeutic alternatives to leishmaniasis chemotherapy, since drugs already approved to human use may be reused, decreasing time and costs needed for the research of new drugs. Leishmania sp. possesses ergosterol as the main membrane lipid, and the metabolic pathway to produce this lipid is complex and involves different enzymes, which if correctly inhibited may suppress ergosterol production and, therefore, parasite viability. Considering these aspects, the aims of this study is to investigate the leishmanicidal potential of drugs who inhibit enzymes of the ergosterol pathway, such as the anti-hyperlipidemic drug rosuvastatin (inhibitor of the 3-hydroxy-3-methyl-glutaryl-CoA reductase), the antifungals voriconazole, tioconazole, fenticonazole, (inhibitors of the 14 Alpha-methylsterol 14-demethylase), naftifine and tolnaftate (inhibitors of squalene epoxidase), and nystatin, that acts directly on ergosterol. The anti-promastigote and anti-amastigote potentials of drugs against L. (L.) amazonensis, L. (L.) infantum and L. (V.) braziliensis were evaluated; ultrastructural and physiological alterations of L. (L.) amazonensis promastigotes (membrane pore formation and mitochondrion membrane potential alterations) and host macrophages (nitric oxide and hydrogen peroxide productions and changes to intracellular pH) were investigated. Fenticonazole, tioconazole, nystatin and tolnaftate were capable to eliminate promastigote and amastigotes, being the most selective drugs nystatin, tolnaftate and fenticonazole to all studied species amastigotes. Rosuvastatin, voriconazole and naftifine were unable to eliminate amastigote forms. Furthermore, the drugs that possess leishmanicidal effects affected parasite mitochondrion. Although these drugs did not trigger the production of H2O2 or NO, fenticonazole was able to alkalinize host infected macrophages. Considering these drugs were able to inhibit multiple species of the parasite growth in macrophages, these results suggest that antifungal drugs can be interesting targets to be repurposed in the cutaneous and visceral leishmaniasis (AU) | |
| FAPESP's process: | 15/17623-6 - Evaluation of the Leishmanicidal Potential from Drugs which Act in the Sterols Biochemical Pathway |
| Grantee: | Eduardo Seiji Yamamoto |
| Support Opportunities: | Scholarships in Brazil - Master |