# Detoxome Capacity of the Adult Rumen Fluke Calicophoron daubneyi Extends into Its Secreted Extracellular Vesicles

## TL;DR

The study explores the detoxification enzymes in the rumen fluke Calicophoron daubneyi, including those in its extracellular vesicles, to better understand its resistance to drugs.

## Contribution

This is the first study to characterize the detoxome of Calicophoron daubneyi, including extracellular vesicle enzyme profiles.

## Key findings

- Transcriptome analysis identified Phase I and II xenobiotic metabolizing enzymes in C. daubneyi.
- Six GST isoforms were identified in adult rumen fluke, with additional variants found through global proteomics.
- Extracellular vesicles of C. daubneyi contain a similar GST profile but lack some isoforms and include a sulfotransferase.

## Abstract

Helminth parasites
have long adapted to survive hostile host environments
and can likely adapt against the chemical anthelmintic challenge.
One proposed adaptation route is via Phase I and II xenobiotic metabolizing
enzymes (XMEs). For successful Helminth pharmacotherapy discovery
programs, a working understanding of Helminth-derived chemical detoxification,
the Helminth detoxome, is a must. At present, the detoxome of a newly
emerging Helminth parasite, the rumen fluke Calicophoron
daubneyi, remains unexplored. Thus, a combined bioinformatics,
sub-, and global-proteomic approach has been employed to examine the
detoxome of adult C. daubneyi. Transcriptome
analysis revealed a complement of Phase I (cytochrome P450s and monoamine
oxygenases) and Phase II (glutathione transferases [GSTs] and sulfotransferases)
XMEs. Affinity-led subproteomic exploration of the GSTs revealed six
GST isoforms in adult rumen fluke (CdGST-Mu1-2, S1, and S3–5),
with global approaches identifying additional GSTs (CdGST-O1-2, Z1,
and S2) and a unique egg-specific variant (CdGST-S6). Examination
of C. daubneyi extracellular vesicles
revealed a GST profile replicating that of the adult with the absence
of two isoforms (CdGST-S2 and S4), with an additional identification
of a sulfotransferase. These data represent the first exploration
into the complete rumen fluke detoxification capacity and will provide
direction for future anthelmintic discovery programs.