Transcriptoma das glândulas de veneno do escorpião peruano Hadruroides lunatus: uma busca por componentes relacionados à síndrome do envenenamento

Abstract

Hadruroides lunatus (Scorpiones, Caraboctonidae) is the scorpion that causes the most accidents in Peru. Few studies have reported the effects of the envenomation caused by this species, and little is known about the diversity of components found in its venom glands, making it difficult to understand the dynamics of this scorpionism (i.e., accident caused by a scorpion sting). Using transcriptomic analysis, we identified 145 components of H. lunatus venom glands that may be associated with the envenomation syndrome. These components were grouped into six families: neurotoxins (n = 15), La1-like peptides (n = 2), cytotoxic linear peptides (n = 35), scorpine-like peptides (n = 3), venom proteins (n = 51) and enzymes (n = 39). We also inferred the transcription level (FPKM) of each of these components. The family of cytotoxic linear peptides – toxic peptides without disulfide bridges – was the one that recorded the highest level of transcription (> 56% of the analyzed transcriptome). The neurotoxin family, the most abundant and expressed group in the venom of Buthidae scorpions, was represented by only five putative KTxs and ten toxin-like peptides that are poorly transcribed in H. lunatus. The abundance of components included in the groups of cytotoxic linear peptides and neurotoxins seems to represent the major differences between the composition of buthid scorpion venoms (i.e., from the family Buthidae) and non-buthid scorpion venoms. The three components classified here as scorpine-like presented the two expected structural domains for this group (N- and C-terminal) and are putative antimicrobials and K+ channel blockers. The peptides generically classified as venom proteins, so called due to the lack of characterization of these components to date, showed a diversity of sequences and a relevant percentage of transcription (51 sequences and about 19% of the transcription level). In the group of H. lunatus enzymes, we identified dozens of components that can act synergistically in the envenomation, and we did not register the activity of the enzyme L-amino acid oxidase (LAAO) using 20 μg of whole H. lunatus venom. Our results show that several of the identified components display motifs and expected conservation patterns for the respective groups. Taken together with the results of new studies on the subject, our findings will provide a better understanding of the biological activities and overall dynamics of scorpionism caused by H. lunatus.