Biochemical and cytotoxic evaluation of latroeggtoxin‐VI against PC12 cells

Abstract

Latroeggtoxin‐VI (LETX‐VI) is a peptide neurotoxin discovered from Latrodectus tredecimguttatus eggs. In the current study, the action features of the neurotoxin on PC12 cells were systematically investigated. LETX‐VI could promote dopamine release from PC12 cells in the absence and presence of Ca2+, involving an even more complex action mechanism in the presence of Ca2+ and when the treatment time was longer. Although LETX‐VI enchanced the autophagy and secretion activity in PC 12 cells, it showed no remarkable influence on the proliferation, cell cycle, apoptosis and ultrastructure of the cells. Pulldown combined with CapLC‐MS/MS analysis suggested that LETX‐VI affected PC12 cells by interacting with multiple proteins involved in the metabolism, transport, and release of neurotransmitters, particularly dopamine. The low cytotoxicity and effective regulatory action of LETX‐VI on PC12 cells suggest the potential of the active peptide in the development of drugs for the treatment of some dopamine‐related psychotic diseases and cancers.

Insights into the mediation of Ca2+ signaling in the promoting effects of LETX-VI on the synthesis and release of dopamine

“…After 50 µM BAPTA‐AM was employed to chelate cytosolic Ca 2+ , LETX‐VI treatment resulted in a certain increase in total dopamine but had no obvious affect on the released dopamine level, irrespective of the addition of extracellular Ca 2+ or not. These observations demonstrate that the promoting effect of LETX‐VI on dopamine release needs the mediation of cytosolic Ca 2+ and suggest that LETX‐VI may also enhance dopamine synthesis in a Ca 2+ ‐independent way (Tang et al 2021a).…”

“…In the transcriptome analysis of the L.tredecimguttatus eggs, Xu et al found a series of genes that encode proteinaceous toxins, two of which were named latroeggtoxin-V and latroeggtoxin-VI, respectively (Xu and Wang 2016). Latroeggtoxin-V was shown to selectively inhibit breast cancer cell lines MDA-MB-231 by affecting the activity of Na + /K + -ATPase (Xu et al 2018) Latroeggtoxin-VI (LETX-VI) can increase the levels of total and released dopamine in PC12 cells, which is influenced by extracellular Ca 2+ and, however, the exact underlying molecular mechanism has not been fully clear (Tang et al 2021a).…”