Transcriptome Profiles of the Protoscoleces of Echinococcus granulosus Reveal that Excretory-Secretory Products Are Essential to Metabolic Adaptation

Abstract

BackgroundCystic hydatid disease (CHD) is caused by the larval stages of the cestode and affects humans and domestic animals worldwide. Protoscoleces (PSCs) are one component of the larval stages that can interact with both definitive and intermediate hosts. Previous genomic and transcriptomic data have provided an overall snapshot of the genomics of the growth and development of this parasite. However, our understanding of how PSCs subvert the immune response of hosts and maintains metabolic adaptation remains unclear. In this study, we used Roche 454 sequencing technology and in silico secretome analysis to explore the transcriptome profiles of the PSCs from E. granulosus and elucidate the potential functions of the excretory-secretory proteins (ESPs) released by the parasite.Methodology/Principal FindingsA large number of nonredundant sequences as unigenes were generated (26,514), of which 22,910 (86.4%) were mapped to the newly published E. granulosus genome and 17,705 (66.8%) were distributed within the coding sequence (CDS) regions. Of the 2,280 ESPs predicted from the transcriptome, 138 ESPs were inferred to be involved in the metabolism of carbohydrates, while 124 ESPs were inferred to be involved in the metabolism of protein. Eleven ESPs were identified as intracellular enzymes that regulate glycolysis/gluconeogenesis (GL/GN) pathways, while a further 44 antigenic proteins, 25 molecular chaperones and four proteases were highly represented. Many proteins were also found to be significantly enriched in development-related signaling pathways, such as the TGF-β receptor pathways and insulin pathways.Conclusions/SignificanceThis study provides valuable information on the metabolic adaptation of parasites to their hosts that can be used to aid the development of novel intervention targets for hydatid treatment and control.

The excretory-secretory products of Echinococcus granulosus protoscoleces stimulated IL-10 production in B cells via TLR-2 signaling

“…These results suggested that EgPSC-ESPs might induce a mixted pro-inflammatory and anti-inflammatory response in B cells, thereby maintaining immunity homeostasis. This seems to be expected, because the ESPs contained diverse components that perform different biological functions [ 43 ].…”

The Echinococcus canadensis (G7) genome: a key knowledge of parasitic platyhelminth human diseases

“…As previously described by Cucher et al [ 15 ], both species are the most frequent in human echinococcosis cases and are sympatric in many countries worldwide. At present, there are only two methods for the treatment of hydatid disease: surgery and the use of benzimidazole, but both have often unsatisfactory results [ 54 ]. Hence, novel treatment compounds are urgently needed.…”

Exosomes and Other Extracellular Vesicles: The New Communicators in Parasite Infections

“…Protozoan parasites similarly secrete a range of immunomodulatory molecules; for example, Trypanosoma cruzi mucins have been associated with suppression of active T cell immune responses by inducing arrest in the cell cycle [10] . Secreted parasite proteins have also been proposed to be involved in metabolic adaptation to the host environment [11] and tissue invasion, where proteases play a major role [12] . In the past 5 years, EVs have been revealed as another component of parasite secretion products that provide a previously unrecognized mechanism to package and protect a set of parasite cargo for uptake and integration into other cells.…”