Participation of PLA2 and PLC in DhL-induced activation ofRhinella arenarumoocytes

Abstract

Rhinella arenarum oocytes can be artificially activated, a process known as parthenogenesis, by a sesquiterpenic lactone of the guaianolide group, dehydroleucodine (DhL). Transient increases in the concentration of cytosolic Ca2+ are essential to trigger egg activation events. In this sense, the 1-4-5 inositol triphosphate receptors (IP3R) seem to be involved in the Ca2+ transient release induced by DhL in this species. We analyzed the involvement of phosphoinositide metabolism, especially the participation of phospholipase A2 (PLA2) and phospholipase C (PLC) in DhL-induced activation. Different doses of quinacrine, aristolochic acid (ATA) (PLA2 inhibitors) or neomycin, an antibiotic that binds to PIP2, thus preventing its hydrolysis, were used in mature Rhinella arenarum oocytes. In order to assay the participation of PI-PLC and PC- PLC we used U73122, a competitive inhibitor of PI-PLC dependent events and D609, an inhibitor of PC-PLC. We found that PLA2 inhibits quinacrine more effectively than ATA. This difference could be explained by the fact that quinacrine is not a specific inhibitor for PLA2 while ATA is specific for this enzyme. With respect to the participation of PLC, a higher decrease in oocyte activation was detected when cells were exposed to neomycin. Inhibition of PC-PLC with D609 and IP-PLC with U73122 indicated that the last PLC has a significant participation in the effect of DhL-induced activation. Results would indicate that DhL induces activation of in vitro matured oocytes of Rhinella arenarum by activation of IP-PLC, which in turn may induce IP3 formation which produces Ca2+ release.

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Early and late stages of Developmental Biology in Argentina

“…They analyzed seasonal changes in the oxidative metabolism and the signaling pathways involved in these processes (Zelarayan et al, 1995;Toranzo et al, 2010). In recent years, they extended their studies to mammals by adopting the Chinchilla lanigera Grey model to study the signaling pathways that participate in the capacitation and acrosomal reaction of epididymal sperm, as well as the location and importance of some sperm proteins involved in gamete interaction (Gramajo-Bühler et al, 2014;Zapata et al, 2016).…”

Development and Validation of a Novel HPLC Method for the Analysis and Quantification of Dehydroleucodine in Plant Extracts

“…2670/2672/2673; Fax: 00-54-261-4494117; E-mail: apenissi@fcm.uncu.edu.ar tinal cytoprotective effects [7][8][9][10][11], mast cell stabilizer action [12,13], aromatase inhibitory activity [14], antioxidant properties [15,16], adipocyte differentiation effects [17] and antimicrobial activities against Pseudomonas aeruginosa [18]. DhL also induces the activation of matured oocytes of Rhinella arenarum in vitro [19,20] and the expression of TP73 and TP53 in human astrocytoma cells [21].…”