Cestode parasites cause neglected diseases, such as echinococcosis and cysticercosis, which represent a significant problem in human and animal health. Benzimidazoles and praziquantel (PZQ) are the only available drugs for chemotherapy and it is therefore important to identify new alternative drugs against cestode parasites. Histone deacetylases (HDACs) are validated drug targets for the treatment of cancer and other diseases, including neglected diseases. However, knowledge of HDACs in cestodes is very scarce. In this work, we investigated cestode HDACs as potential drug targets to develop new therapies against neglected diseases caused by cestodes. We showed that Trichostatin A (TSA), a pan-HDAC inhibitor, decreases the viability of M. corti, alters its tegument and morphology and produces an increment of the total amount of acetylated proteins, including acetylated histone H4.
Material and Methods
The stock solutions of TSA (Cell Signaling Technology, U.S.A.) and PZQ were prepared in 100% DMSO at 200x of the maximum concentration to be used. In order to determine the effect of the pan-HDAC inhibitor TSA on M. corti TTy, this compound was tested at concentrations in the range from 1 μM to 20μM. Also, concentrations of PZQ from 1 μM to 20μM were tested. Parasites pre-treated with ethanol 70% for 30 min were used as positive control. All assays were performed with equal amount of the vehicle (1% DMSO final concentration) and with its corresponding negative control (1% DMSO). The assay of motility was performed using a worm tracker device (WMicrotracker). Five parasites TTy were incubated in 200 μL of culture medium per well in U-shape96-well microplates (Greiner Bio-One, Germany). The motility index was calculated as previously described in Camicia et al. (2013, 2018).
Results
The motility assay showed that TSA produced a decrease of relative motility indexes on treated-TTy at 6 days compared to untreated-TTy (p < 0.0001 for 1 μM, 10 μM and 20 μM TSA) (Fig. 7B). These results suggest that HDAC from cestodes are functional and might play important roles in survival and development.
Fig. 7. Effect of Trichostatin A (TSA) on viability of Mesocestoides corti tetrathyridium (TTy) in culture. (B) the motility assay by worm tracker device at 6 days of M.corti TT y treatment. TTy were incubated in 200 μL of culture medium with 1, 10 and 20 μM of TSA or the vehicle (DMSO 1%). Three independent biological replicates were used. Error bars represent the SD. Praziquantel (PZQ) and ethanol 70% (EtOH 70%) were used as positive controls. In all panels, asterisks indicate those values showing differences with statistical significance compared to control according to ANOVA tests (***, p < 0.001; ****, p < 0.0001).
Int J Parasitol Drugs Drug Resist. 2019 Apr;9:120-132. doi: 10.1016/j.ijpddr.2019.02.003. Epub 2019 Feb 23.
Hugo R. Vaca, Ana M. Celentano, Natalia Macchiaroli, Laura Kamenetzky, Federico Camicia, Mara C. Rosenzvit