In vitro parasiticidal effects of PIK-75 inhibition of Nrf2 against Echinococcus granulosus protoscoleces

Abstract

Introduction The aims of this study were to investigate the role of the nuclear factor E2-related factor 2 (Nrf2) signaling pathway in Echinococcus granulosus protoscoleces, and to examine the effects of PIK-75 inhibition on Nrf2 activity. Methods Nrf2 protein expression and localization in protoscoleces were examined via confocal immunofluorescence microscopy. Reactive oxygen species (ROS detection kit) was used to detect ROS level in protoscoleces. The effects of PIK-75 on activity of heme oxygenase1(HO-1), NAD(P)H quinone oxidoreductase 1 (NQO1), glutathione peroxidase (GSH-Px) and thioredoxin peroxidase (TPx) were characterized using ELISA. Evidence of parasite damage and death was observed by scanning electron microscopy(SEM). Western bolting was used to detect the expression level of Nrf2 protein. In addition, caspase-3 activity was detected using an assay kit. Results The study found that Nrf2 is primarily localized in the protoscoleces cytoplasm, and PIK-75 treatment could increased ROS level(P<0.05) in the early time, and reduced NQO-1, HO-1, GSH-Px and TPx (P<0.05) activity in protoscoleces. SEM showed that PIK-75-treated protoscoleces presented damage in the protoscoleces region. Western-blot showed that the Nrf2 protein expression had decreased significantly. Caspase-3 activity clearly increased in protoscoleces treated for 24 and 48 h with PIK-75 compared with that in controls (P<0.05). Conclusion The present investigation demonstrated that PIK-75 had an inhibitory effect on the Nrf2 signaling pathway. We also provide evidence that PIK-75 may serve as a potential therapeutic agent for the treatment of protoscoleces. The use of PIK-75 as a treatment for protoscoleces, however, requires further research.