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Trypanosoma cruzi is a protozoan of great medical interest since it is the causative agent of Chagas disease, an endemic condition in Latin America. This parasite undergoes epigenetic events, such as phosphorylation, methylation and acetylation, which play a role in several cellular processes including replication, transcription and gene expression. Histone deacetylases (HDAC) are involved in chromatin compaction and post-translational modifications of cytoplasmic proteins, such as tubulin. Tubastatin A (TST) is a specific HDAC6 inhibitor that affects cell growth and promotes structural modifications in cancer cells and parasites. In the present study, we demonstrated that T. cruzi epimastigote cell proliferation and viability are reduced after 72 h of TST treatment. The results obtained through different microscopy methodologies suggest that this inhibitor impairs the polymerization dynamics of cytoskeleton microtubules, generating protozoa displaying atypical morphology and cellular patterns that include polynucleated parasites. Furthermore, the microtubules of treated protozoa were more intensely acetylated, especially at the anterior portion of the cell body. A cell cycle analysis demonstrated an increase in the number of trypanosomatids in the G2/M phase. Together, our results suggest that TST should be explored as a tool to study trypanosomatid cell biology, including microtubule cytoskeleton dynamics, and as an antiparasitic drug., (Copyright © 2021 Elsevier GmbH. All rights reserved.)

Trypanosoma cruzi, the causative agent of Chagas disease, is a public health concern in Latin America. Epigenetic events, such as histone acetylation, affect DNA topology, replication and gene expression. Histone deacetylases (HDACs) are involved in chromatin compaction and post-translational modifications of cytoplasmic proteins, such as tubulin. HDAC inhibitors, like trichostatin A (TSA), inhibit tumour cell proliferation and promotes ultrastructural modifications. In the present study, TSA effects on cell proliferation, viability, cell cycle and ultrastructure were evaluated, as well as on histone acetylation and tubulin expression of the T. cruzi epimastigote form. Protozoa proliferation and viability were reduced after treatment with TSA. Quantitative proteomic analyses revealed an increase in histone acetylation after 72 h of TSA treatment. Surprisingly, results obtained by different microscopy methodologies indicate that TSA does not affect chromatin compaction, but alters microtubule cytoskeleton dynamics and impair kDNA segregation, generating polynucleated cells with atypical morphology. Confocal fluorescence microscopy and flow cytometry assays indicated that treated cell microtubules were more intensely acetylated. Increases in tubulin acetylation may be directly related to the higher number of parasites in the G2/M phase after TSA treatment. Taken together, these results suggest that deacetylase inhibitors represent excellent tools for understanding trypanosomatid cell biology.