Examinando por Autor "Tavernelli, Luis Emilio"
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Ítem Acceso Abierto 1,3,4-oxadiazoles as inhibitors of the atypical member of the BET family bromodomain factor 3 from Trypanosoma cruzi (TcBDF3)(Frontiers, 2024-10-01) Alonso, Victoria Lucía; Escalante, Andrea Marta; Rodríguez Araya, Elvio; Frattini, Gianfranco; Tavernelli, Luis Emilio; Moreno, Diego M.; Furlán, Ricardo Luis Eugenio; Serra, Esteban CarlosChagas disease, caused by the protozoan parasite Trypanosoma cruzi, affects millions globally, with increasing urban cases outside of Latin America. Treatment is based on two compounds, namely, benznidazole (BZ) and nifurtimox, but chronic cases pose several challenges. Targeting lysine acetylation, particularly bromodomain-containing proteins, shows promise as a novel antiparasitic target. Our research focuses on TcBDF3, a cytoplasmic protein, which is crucial for parasite differentiation that recognizes acetylated alpha-tubulin. In our previous study, A1B4 was identified as a high-affinity binder of TcBDF3, showing significant trypanocidal activity with low host toxicity in vitro. In this report, the binding of TcBDF3 to A1B4 was validated using differential scanning fluorescence, fluorescence polarization, and molecular modeling, confirming its specific interaction. Additionally, two new 1,3,4-oxadiazoles derived from A1B4 were identified, which exhibited improved trypanocide activity and cytotoxicity profiles. Furthermore, TcBDF3 was classified for the first time as an atypical divergent member of the bromodomain extraterminal family found in protists and plants. These results make TcBDF3 a unique target due to its localization and known functions not shared with higher eukaryotes, which holds promise for Chagas disease treatment.Ítem Acceso Abierto Alpha-tubulin acetylation in Trypanosoma cruzi: a dynamic instabilityof microtubules is required for replication and cell cycle progression(Frontiers Media, 2021-03-11) Alonso, Victoria Lucía; Carloni, Mara Emilia; Silva Gonçalves, Camila; Martínez Peralta, Gonzálo; Chesta, Maria Eugenia; Pezza, Alejandro; Tavernelli, Luis Emilio; Motta, María Cristina M.; Serra, Esteban CarlosTrypanosomatids have a cytoskeleton arrangement that is simpler than what is found in most eukaryotic cells. However, it is precisely organized and constituted by stable microtubules. Such microtubules compose the mitotic spindle during mitosis, the basal body, the flagellar axoneme and the subpellicular microtubules, which are connected to each other and also to the plasma membrane forming a helical arrangement along the central axis of the parasite cell body. Subpellicular, mitotic and axonemal microtubules are extensively acetylated in Trypanosoma cruzi. Acetylation on lysine (K) 40 of a-tubulin is conserved from lower eukaryotes to mammals and is associated with microtubule stability. It is also known that K40 acetylation occurs significantly on flagella, centrioles, cilia, basal body and the mitotic spindle in eukaryotes. Several tubulin posttranslational modifications, including acetylation of K40, have been cataloged in trypanosomatids, but the functional importance of these modifications for microtubule dynamics and parasite biology remains largely undefined. The primary tubulin acetyltransferase was recently identified in several eukaryotes as Mec-17/ATAT, a Gcn5-related N-acetyltransferase. Here, we report that T. cruzi ATAT acetylates a-tubulin in vivo and is capable of autoacetylation. TcATAT is located in the cytoskeleton and flagella of epimastigotes and colocalizes with acetylated a-tubulin in these structures. We have expressed TcATAT with an HA tag using the inducible vector pTcINDEX-GW in T. cruzi. Over-expression of TcATAT causes increased levels of the alpha tubulin acetylated species, induces morphological and ultrastructural defects, especially in the mitochondrion, and causes a halt in the cell cycle progression of epimastigotes, which is related to an impairment of the kinetoplast division. Finally, as a result of TcATAT over-expression we observed thatÍtem Acceso Abierto Identification of novel bromodomain inhibitors of Trypanosoma cruzi bromodomain factor 2 (TcBDF2) using a fluorescence polarization-based high-throughput assay(American Society for Microbiology, 2024-06-19) Tavernelli, Luis Emilio; Alonso, Victoria Lucía; Peña, Imanol; Rodríguez Araya, Elvio; Manarin, Romina; Cantizani, Juan; Martin, Julio; Salamanca, Juan; Bamborough, Paul; Calderón, Felix; Gabarro, Raquel; Serra, Esteban Carlos; http://orcid.org/0000-0001-5986-7459Bromodomains are structural folds present in all eukaryotic cells that bind to other proteins recognizing acetylated lysines. Most proteins with bromodomains are part of nuclear complexes that interact with acetylated histone residues and regulate DNA replication, transcription, and repair through chromatin structure remodeling. Bromodomain inhibitors are small molecules that bind to the hydrophobic pocket of bromodomains, interfering with the interaction with acetylated histones. Using a fluorescent probe, we have developed an assay to select inhibitors of the bromodomain factor 2 of Trypanosoma cruzi (TcBDF2) using fluorescence polarization. Initially, a library of 28,251 compounds was screened in an endpoint assay. The top 350-ranked compounds were further analyzed in a dose-response assay. From this analysis, seven compounds were obtained that had not been previously characterized as bromodomain inhibitors. Although these compounds did not exhibit significant trypanocidal activity, all showed bona fide interaction with TcBDF2 with dissociation constants between 1 and 3 µM validating these assays to search for bromodomain inhibitors.Ítem Acceso Abierto Overexpression of Trypanosoma cruzi high mobility group B protein (TcHMGB) alters the nuclear structure, impairs cytokinesis and reduces the parasite infectivity(Springer Nature, 2019-01-17) Tavernelli, Luis Emilio; Motta, María Cristina M.; Silva Gonçalves, Camila; Santos da Silva, Marcelo; Elías, María Carolina; Alonso, Victoria Lucía; Serra, Esteban Carlos; Cribb, Pamela; Dr. De Gaudenzi, Javier: provide the pTcINDEX-eGFP strainKinetoplastid parasites, included Trypanosoma cruzi, the causal agent of Chagas disease, present a unique genome organization and gene expression. Although they control gene expression mainly post-transcriptionally, chromatin accessibility plays a fundamental role in transcription initiation control. We have previously shown that High Mobility Group B protein from Trypanosoma cruzi (TcHMGB) can bind DNA in vitro. Here, we show that TcHMGB also acts as an architectural protein in vivo, since the overexpression of this protein induces changes in the nuclear structure, mainly the reduction of the nucleolus and a decrease in the heterochromatin:euchromatin ratio. Epimastigote replication rate was markedly reduced presumably due to a delayed cell cycle progression with accumulation of parasites in G2/M phase and impaired cytokinesis. Some functions involved in pathogenesis were also altered in TcHMGB-overexpressing parasites, like the decreased efficiency of trypomastigotes to infect cells in vitro, the reduction of intracellular amastigotes replication and the number of released trypomastigotes. Taken together, our results suggest that the TcHMGB protein is a pleiotropic player that controls cell phenotype and it is involved in key cellular processes.Ítem Acceso Abierto Trypanosoma cruzi High Mobility Group B (TcHMGB) can act as an inflammatory mediator on mammalian cells(Public Library of Science (PLOS), 2017-02-08) Cribb, Pamela; Perdomo, Virginia Gabriela; Alonso, Victoria Lucía; Manarin, Romina; Barrios-Payán, Jorge; Marquina-Castillo, Brenda; Tavernelli, Luis Emilio; Hernández-Pando, Rogelio