Transcription profile and heterologous expression of Echinococcus granulosus aquaporins genes in the encysted protoscolex

Abstract

Objective To explore the role of Echinococcus granulosus aquaporins (EgAQPs) in the accumulation of hydatid fluid. Methods The secondary hydatids cultured in vitro and inoculated in BALB/c mice were collected respectively, and the relative transcription expression levels of 12 EgAQPs genes from the hydatid cysts cultured in vitro and in mice were detected by RT-qPCR. Six gene coding region fragments of EgAQP, EgAQP1, EgAQP3, EgAQP4-1, EgAQP4-4 and EgAQP9-1 were amplified using cDNA templates. The other 6 genes coding region fragments of EgAQPs (EgAQPAn.G, EgAQPFA-CHIP, EgAQP4-2, EgAQP4-3, EgAQP4-5 and EgAQP9-2) were amplified with chemical synthesis. The water permeability of these 12 EgAQPs genes were detected in Xenopus laevis (X. laevis), and the expression of EgAQPs on the oocytes membranes was detected by Western blotting. Results The volume of hydatid cultured in vitro and in vivo was increased gradually with the extension of culture time, and there was more and more transparent hydatid fluid in hydatid cyst. The results of RT-qPCR showed that the relative transcription levels of EgAQPs genes in the hydatid cysts were very low or even undetectable except for EgAQP3 and EgAQP9-1 at the beginning of culture in vitro. There were no significant differences in relative volume change rates and water permeability coefficients of X. laevis oocytes injected with EgAQPs genes when compared with the negative control, and these EgAQPs genes did not show water channel functions in the oocytes. Western blot assay displayed that there was no expression of EgAQPs genes in total, cytoplasmic and membrane protein on the oocytes. Conclusion The transcription levels of EgAQPs genes are quite low in the encystation process of protoscolex, and their heterologous expression do not show water channel functions in X. laevis oocytes.

Keywords

• echinococcus granulosus
• aquaporin
• protoscolex
• hydatid
• transcription profile
• heterologous expression