Identification of Functional MKK3/6 and MEK1/2 Homologs from Echinococcus granulosus and Investigation of Protoscolecidal Activity of Mitogen-Activated Protein Kinase Signaling Pathway Inhibitors In Vitro and In Vivo

Abstract

Cystic echinococcosis is a zoonosis caused by the larval stage of Echinococcus granulosus sensu lato. There is an urgent need to develop new drugs for the treatment of this disease. In this study, we identified two new members of mitogen-activated protein kinase (MAPK) cascades, MKK3/6 and MEK1/2 homologs (termed EgMKK1 and EgMKK2, respectively), from E. granulosus sensu stricto. Both EgMKK1 and EgMKK2 were expressed at the larval stages. As shown by yeast two-hybrid and coimmunoprecipitation analyses, EgMKK1 interacted with the previously identified Egp38 protein but not with EgERK. EgMKK2, on the other hand, interacted with EgERK. In addition, EgMKK1 and EgMKK2 displayed kinase activity toward the substrate myelin basic protein. When sorafenib tosylate, PD184352, or U0126-ethanol (EtOH) was added to the medium for in vitro culture of E. granulosus protoscoleces (PSCs) or cysts, an inhibitory and cytolytic effect was observed via suppressed phosphorylation of EgMKKs and EgERK. Nonviability of PSCs treated with sorafenib tosylate or U0126-EtOH, and not with PD184352, was confirmed through bioassays, i.e., inoculation of treated and untreated protoscoleces into mice. In vivo treatment of E. granulosus sensu stricto-infected mice with sorafenib tosylate or U0126-EtOH for 4 weeks demonstrated a reduction in parasite weight, but the results did not show a significant difference. In conclusion, the MAPK cascades were identified as new targets for drug development, and E. granulosus was efficiently inhibited by their inhibitors in vitro. The translation of these findings into in vivo efficacy requires further adjustment of treatment regimens using sorafenib tosylate or, possibly, other kinase inhibitors.

Comprehensive Analysis of Non-coding RNA Profiles of Exosome-Like Vesicles From the Protoscoleces and Hydatid Cyst Fluid of Echinococcus granulosus

“…KEGG pathway analysis further demonstrated that the mRNAs targeted by the miRNAs were mainly involved in the regulation of signal transduction, infectious diseases, and the immune system, which have been widely researched and demonstrated to be associated with the functions of exosomes (Coakley et al, 2015 ). The predicted host target genes are involved in the inflammatory responses, including encoding members of the TNF, TLR, MAPK, and NF-κB signaling pathways, which have previously been documented to modulate cytokines during chronic E. granulosus infection (Refik et al, 2005 ; Tuxun et al, 2015 ; Labsi et al, 2018 ; Zhang et al, 2019 ). Additionally, the most abundant miRNAs were predicted to participate in Th1 and Th2 cell differentiation, Th17 cell differentiation, and IL-17 signaling pathway, and these immune responses occur during E. granulosus infections (Tuxun et al, 2012 ; Labsi et al, 2018 ).…”

In Vitro and In Vivo Efficacies of the EGFR/MEK/ERK Signaling Inhibitors in the Treatment of Alveolar Echinococcosis

“…EGFR-mediated activation of the Ras/Raf/MEK/ERK signaling pathway has been demonstrated in E. multilocularis , and some drugs have been shown to inhibit the activation of the signaling in the parasite ( 13 , 21 , 22 ). U0126 was recently shown to display significant in vitro effect on protoscoleces of the closely related species E. granulosus and reduce, but not significantly, parasite burden in mice ( 23 ). In the present study, U0126 treatment resulted in significantly reduced parasite weight, despite the lower reduction in parasite burden in comparison with BIBW2992 and albendazole treatments.…”

Dynamic Changes in the Global Transcriptome and MicroRNAome Reveal Complex miRNA-mRNA Regulation in Early Stages of the Bi-Directional Development of Echinococcus granulosus Protoscoleces

“…We showed that miR-71 was significantly highly expressed in NSD and down-regulated in SSD, and suggest that its targets may be involved in the regulation of the MAPK and Wnt signaling pathways in SSD. A recent study proposed that MAPK may be a therapeutic target in E. granulosus through the suppression of MKK3/6 and MEK1/2 (Zhang et al, 2019). Furthermore, some Wnt-pathway related proteins, such as the frizzled receptor eg-fz4, have been shown to be highly expressed in PSC cultured in vitro toward adult maturation, and that they may be involved in early development of the nervous system and gut-derived organs (Pan et al, 2006;Dezaki et al, 2016;Zidek et al, 2018).…”