Abstract

In recent years, a class of chemical compounds (benzoxaboroles) that are active against a range of parasites has been shown to target mRNA polyadenylation by inhibiting the activity of CPSF73, the endonucleolytic core of the eukaryotic polyadenylation complex. One particular compound, termed AN3661, is active against several apicomplexan parasites that cause disease in humans. In this study, we report that AN3661 is active against an apicomplexan that causes disease in horses and marine mammals (Sarcocystis neurona), with an approximate IC50 value of 14.99 nM. Consistent with the reported mode of action of AN3661 against other apicomplexans, S. neurona mutants resistant to AN3661 had an alteration in CPSF73 that was identical to a mutation previously documented in AN3661-resistant Toxoplasma gondii and Plasmodium falciparum. AN3661 had a wide-ranging effect on poly(A) site choice in S. neurona, with more than half of all expressed genes showing some alteration in mRNA 3’ ends. This was accompanied by changes in the relative expression of more than 25% of S. neurona genes and an overall 5-fold reduction of S. neurona transcripts in infected cells. In contrast, AN3661 had no discernible effect on poly(A) site choice or gene expression in the host cells. These transcriptomic studies indicate that AN3661 is exceedingly specific for the parasite CPSF73 protein, and has the potential to augment other therapies for the control of apicomplexan parasites in domestic animals.

Document Type

Article

Publication Date

10-28-2021

Notes/Citation Information

Published in PLOS ONE, v. 16, issue 10, e0259109.

© 2021 Hunt et al.

This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Digital Object Identifier (DOI)

https://doi.org/10.1371/journal.pone.0259109

Funding Information

This research was supported by the USDA National Institute of Food and Agriculture (AGH - Hatch project accession #1020849 and DKH – Hatch project accession 1012262; https://nifa.usda.gov/) and the Amerman Family Equine Research Fund (DKH).

Related Content

The high throughput sequencing data associated with this project are available under Bioproject PRJNA713353. https://www.ncbi.nlm.nih.gov/bioproject/PRJNA713353.

pone.0259109.s001.pdf (634 kB)
S1 Fig. Changes in transcriptional dynamics in S. neurona treated with AN3661. Browser tracks showing examples of changes in poly(A) site usage in AN3661-treated cells. The order for each representation is (top to bottom): chromosomal location (in bp), gene annotation, coding region (CDS) annotation, reads from un-treated cells (Sn3 mapping), and reads from AN3661-treated cells (A90-1 mapping). Reads colored green are oriented in the sense (5’->3’ left to right) direction, and reads colored green are oriented in the antisense direction. Tracks were created using CLC Genomics Workbench. https://doi.org/10.1371/journal.pone.0259109.s001

pone.0259109.s002.xlsx (9 kB)
S1 Table. Primers used in this study. https://doi.org/10.1371/journal.pone.0259109.s002

pone.0259109.s003.xlsx (13 kB)
S1 File. Reads and mapping statistics. https://doi.org/10.1371/journal.pone.0259109.s003

pone.0259109.s004.docx (26 kB)
S2 File. Analysis pipeline for poly(A) site determinations. https://doi.org/10.1371/journal.pone.0259109.s004

pone.0259109.s005.xlsx (1560 kB)
S3 File. Gene expression analysis in AN3661-treated S. neurona. S. neurona-infected BT cells were treated with 90 nM AN3661, RNA isolated, and PATSeq libraries constructed and sequenced. PATSeq reads were used to assess gene expression in drug-treated S. neurona cells. https://doi.org/10.1371/journal.pone.0259109.s005

pone.0259109.s006.xlsx (10666 kB)
S4 File. Poly(A) site analysis in AN3661-treated S. neurona. S. neurona-infected BT cells were treated with 90 nM AN3661, RNA isolated, and PATSeq libraries constructed and sequenced. The data were used to assess poly(A) site choice in the parasite in the two conditions. https://doi.org/10.1371/journal.pone.0259109.s006

pone.0259109.s007.xlsx (3043 kB)
S5 File. Gene expression in control and AN3661-treated BT cells. RNA was isolated from control and AN3661-treated BT cells and PATSeq libraries constructed and sequenced. PATSeq reads were used to assess host gene expression. https://doi.org/10.1371/journal.pone.0259109.s007

pone.0259109.s008.xlsx (3602 kB)
S6 File. Host gene expression in uninfected and S. neurona- infected BT cells. RNA was isolated from control and S. neurona-infected BT cells and PATSeq libraries constructed and sequenced. PATSeq reads were used to assess host gene expression. https://doi.org/10.1371/journal.pone.0259109.s008

pone.0259109.s009.xlsx (5392 kB)
S7 File. Poly(A) site analysis in AN3661-treated BT host cells. RNA was isolated from control and AN3661-treated BT cells and PATSeq libraries constructed and sequenced. The data were used to assess poly(A) site choice in the host in the two conditions. https://doi.org/10.1371/journal.pone.0259109.s009

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