Efeito tripanocida do análogo [ARG]4 M-PONTX-DQ3A [1-15] da dinoponeratoxina M-PONTXDQ3A [1-15] e ação sobre a enzima gliceraldeído 3-fosfato desidrogenase

Abstract

Chagas disease (CD) is a neglected public health problem worldwide, which contains benznidazole (BZN) as the only treatment option in Brazil, a drug that has limited effectiveness and significant adverse effects. In this context, there is a need to seek therapeutic strategies that promote greater selectivity on the parasite without causing complications for the host. The venom of the giant ant Dinoponera quadriceps is rich in peptides called dinoponeratoxins (Dntxs), classified as antimicrobial peptides (AMPs). In previous studies, Dntx M-PONTX Dq3a showed a trypanocidal effect on the main evolutionary forms of Trypanosoma cruzi, and was therefore considered promising. Its fragment, Dntx M-PONTX-Dq3a [1-15], demonstrated an effect very similar to the parent peptide, in addition to a smaller size, implying reduced production costs. Despite this, the possibility of improving the activity of M-PONTX-Dq3a [1-15] led to the creation of several analogues, one of which is the analogue [Arg]4-M-PONTX-Dq3a [1-15] addressed in this study. Thus, the objective of this work was to evaluate the trypanocidal effect of the analog [Arg]4-M-PONTX-Dq3a [1-15], and its action on the enzyme glyceraldehyde 3-phosphate dehydrogenase (TcGAPDH), important for the survival of the parasite. For this, tests were carried out on the trypomastigotes of the Y strain of T. cruzi. In trypomastigotes, the analogue [Arg]4-M-PONTX Dq3a [1-15] was observed to have an IC50 of 1.09 µM, with an effect 148 times greater than that of benznidazole. In molecular docking studies, the peptide under study showed a favorable interaction with the TcGAPDH enzyme, mainly in the regions of residues Thr167, Cys166 and Ile13. For this, the evaluation of the trypanocidal activity in the epimastigotes forms was carried out to determine the concentrations used in the dosage of the enzymatic activity, obtaining an IC50 >19.2 at 24, 48 and 72 hours. The evaluation of enzymatic activity was performed at concentrations of 19.2; 9.6 and 4.8 µM, at 2 hours, 1 hour, 30 minutes and 15 minutes, respectively, with no significant difference between the times and concentrations tested, but with a reduction in enzymatic activity. In conclusion, the analogue [Arg]4-M-PONTX-Dq3a [1- 15] has great potential, as it has effects on the infective form of T. cruzi, reducing the activity of TcGAPDH, an important pharmacological target for the disease of Nasturtium