Antioxidant and Neuroprotective Effects of the First Tryptophyllin Found in Snake Venom (Bothrops moojeni)

Abstract

In this study, we report the isolation, characterization, and synthesis of the peptide BmT-2 belonging to the tryptophyllins family, isolated from the venom of the snake Bothrops moojeni. This is the first time a tryptophyllin is identified in snake venom. We tested whether BmT-2 had cytotoxic effects and antioxidant activity in a set of experiments that included both in vitro and cell-based assays. BmT-2 presented a radical scavenging activity toward ABTS• and AAPH-derived radicals. BmT-2 protected fluorescein, DNA molecules, and human red blood cells (RBCs) from free radicals generated by the thermal decomposition of AAPH. The novel tryptophyllin was not toxic in cell viability tests, where it (up to 0.4 mg/mL) did not cause hemolysis of human RBCs and did not cause significant loss of cell viability, showing a CC50 > 1.5 mM for cytotoxic effects against SK-N-BE(2) neuroblastoma cells. BmT-2 prevented the arsenite-induced upregulation of Nrf2 in Neuro-2a neuroblasts and the phorbol myristate acetate-induced overgeneration of reactive oxygen species and reactive nitrogen species in SK-N-BE(2) neuroblastoma cells. Electronic structure calculations and full atomistic reactive molecular dynamics simulations revealed the relevant contribution of aromatic residues in BmT-2 to its antioxidant properties. Our study presents a novel peptide classified into the family of the tryptophyllins, which has been reported exclusively in amphibians. Despite the promising results on its antioxidant activity and low cytotoxicity, the mechanisms of action of BmT-2 still need to be further elucidated.

Purification, Conformational Analysis and Cytotoxic Activities of Host-Defense Peptides from the Giant Gladiator Treefrog Boana boans (Hylidae: Hylinae)

“…The term tryptophyllin refers to a heterogeneous group of small (<10 amino acid residues) peptides containing one or more tryptophan and one or more proline residues. Multiple tryptophyllins have been identified in the skins of several species of frogs belonging to the sub-families Pelodryadinae and Phyllomedusinae (reviewed in [2,20,30]) but have also been isolated from skin secretions of the most primitive extant anuran, the tailed frog Ascaphus truei [31] and, more recently, from the venom of the snake Bothrops moojeni [32]. Classification of tryptophyllins together in a single group is largely a matter of convenience and does not necessarily mean that its members are evolutionarily or biosynthetically related.…”

Molecular and cellular mechanisms of neuroprotection by oligopeptides from snake venoms

“…Some PROs of B. jararaca were examined for their potential as antioxidants, but the PROs 5a, 7a, and 10c were incapable of capturing free radicals [36,45]. However, the BmT-2 peptide (FPWIIS-NH 2 ) was identified in B. moojeni and belongs to the tryptophyllin family and showed antioxidant functions [59]. Tryptophyllins are a class of peptides found in the skin secretions of amphibians [59].…”

“…However, the BmT-2 peptide (FPWIIS-NH 2 ) was identified in B. moojeni and belongs to the tryptophyllin family and showed antioxidant functions [59]. Tryptophyllins are a class of peptides found in the skin secretions of amphibians [59]. The inclusion of aromatic residues in the main structure of tryptophyllins, such as BmT-2, significantly contributes to their antioxidant effects [59,60].…”

“…Tryptophyllins are a class of peptides found in the skin secretions of amphibians [59]. The inclusion of aromatic residues in the main structure of tryptophyllins, such as BmT-2, significantly contributes to their antioxidant effects [59,60].…”