A common strategy to identify new antiparasitic agents is the targeting of proteases due to their essential contribution to parasite growth and development. Metacaspases (MCAs) are cysteine proteases present in fungi, protozoa and plants. These enzymes, which are associated with crucial cellular events in trypanosomes, are absent in the human host, thus arising as attractive drug targets. To find new MCA inhibitors with trypanocidal activity, we adapted a continuous fluorescent enzymatic assay to a medium-throughput format and carried out screening of different compound collections, followed by the construction of dose-response curves for the most promising hits. We used MCA5 from T. brucei (TbMCA5) as a model for the identification of inhibitors from the GlaxoSmithKline HAT and CHAGAS chemical boxes. We also assessed a third collection of 9 compounds from the Maybridge database identified by virtual screening as potential inhibitors of the cysteine peptidase falcipain-2 (Clan CA) from Plasmodium falciparum. Compound HTS01959 (from the Maybridge collection) was the most potent inhibitor with IC50 of 14.39 μM; also inhibiting other MCAs from T. brucei and T. cruzi (TbMCA2=4.14 μM, TbMCA3=5.04 μM and TcMCA5=151 μM). HTS01959 behaved as a reversible, slow binding and noncompetitive inhibitor of TbMCA2, with a mechanism of action that included redox components. Importantly, HTS01959 displayed trypanocidal activity against bloodstream forms of T. brucei and trypomastigotes forms of T. cruzi, without cytotoxic effect on VERO cells. Thus, HTS01959 is a promising starting point to develop more specific and potent chemical structures to target MCAs.

Resumen:La geografía ha evolucionado orientando sus objetos de estudio y metodología por los procesos económicos y políticos de la época. Esto también ha condicionado la forma en que el Estado ejerce un control sobre su territorio, marcando las pautas de intervención e interpretación del espacio por medio de los preceptos geográficos del momento. México pasó por un proceso de liberalización del territorio entre los siglos XVIII y XIX, lo que derivó en una revolución en el desempeño de la geografía. Esto, a su vez, marcó los procesos de reproducción del espacio en el siglo xix, como la delimitación territorial del Distrito Federal y otras entidades. Palabras clave: Distrito Federal, fronteras, cartografía, geografía, liberalización del territorio. Abstract:Geography has evolved by shifting its objects of study and methodology in response to the economic and political processes of the moment. This has also conditioned the way in which the state exercises control over its territory, setting the intervention and interpretative guidelines of space according to the current geographical precepts. Mexico went through a process of land liberalization between the 18th and 19th centuries, resulting in a revolution in the practice of geography. This in turn marked the processes of reproduction of space in the 19th century, such as the territorial delimitation of the Federal District and other entities. Key words: Distrito Federal, borders, cartography, geography, liberalization. Recepción: 7 de enero de 2021                                             Aceptación: 5 de abril de 2021