Alberto-Silva_2024_Toxins.(Basel)_16_

A comprehensive LC-MS study examined the venom components of the solitary scoliid wasp Scolia oculata. Online mass fingerprinting showed that crude venom contains 25 small molecules (amino acids, biogenic amines, and nucleosides/nucleotides) and 45 peptides with MW 400-2700. The small molecules were identified by elemental composition analysis, and peptide sequences were determined by ESI-MS/MS and MALDI-TOF/TOF MS analyses. As major peptide components, a known peptide, beta-scoliidine (DYVTVKGFSPLRKA), and three new peptides, gamma-scoliidine (YVTVKGFSPLR), delta-scoliidine (YVTVKGFSPLREP) and sigma-scoliidine (DYVTVKGFSPLREP) were identified, all of which are closely homologous to each other. Once the neuroprotective effects of beta-scoliidine have already been described, the other three new scoliidine peptides were analyzed against oxidative stress-induced toxicity in PC12 neuronal cells by mitochondrial metabolism assay, and the structure-activity relationship was evaluated. Interestingly, pre-treatment with sigma-scoliidine increased the mitochondrial metabolism of PC12 cells (106 +/- 3.6%; p = 0.007) exposed to H(2)O(2)-induced oxidative stress in contrast to gamma- and delta-scoliidines (77.6 +/- 4.8 and 68.5 +/- 4.1%, respectively) in compared to cells treated only H(2)O(2) (75.8 +/- 2.4%). These new peptides were also analyzed for enzyme inhibitor/substrate assays with angiotensin-converting enzyme (ACE), neprilysin (NEP), and acetylcholinesterase (AChE). In these assays, only delta- and sigma-scoliidines increased the AChE activity (128.7 +/- 3.8%; p = 0.01; and 116.8 +/- 3.8% p = 0.03; respectively) in relation to basal activity (100.1 +/- 1.6%). In addition, the four peptides were analyzed through in silico analysis, and none of them demonstrated possible hemolytic and toxic activities. In our study, the comprehensive LC-MS and MS/MS analyses of Scolia oculate venom identified four major peptide components of the venom beta-, gamma-, delta- and sigma-scoliidines, and small differences in their primary structures are important to their neuroprotective properties.