Transcriptional responses of in vivo praziquantel exposure in schistosomes identifies a functional role for calcium signalling pathway member CamKII

You, Hong, McManus, Donald P., Hu, Wei, Smout, Michael J., Brindley, Paul J., and Gobert, Geoffrey N. (2013) Transcriptional responses of in vivo praziquantel exposure in schistosomes identifies a functional role for calcium signalling pathway member CamKII. PLoS Pathogens, 9 (3). e1003254.

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Abstract

Treatment for clinical schistosomiasis has relied centrally on the broad spectrum anthelmintic praziquantel; however, there is limited information on its mode of action or the molecular response of the parasite. This paper presents a transcriptional and functional approach to defining the molecular responses of schistosomes to praziquantel. Differential gene expression in Schistosoma japonicum was investigated by transcriptome-wide microarray analysis of adult worms perfused from infected mice after 0.5 to 24 hours after oral administration of sub-lethal doses of praziquantel. Genes up-regulated initially in male parasites were associated with "Tegument/Muscle Repair" and "Lipid/Ion Regulation" functions and were followed by "Drug Resistance" and "Ion Regulation" associated genes. Prominent responses induced in female worms included upregulation of "Ca²⁺ Regulation" and "Drug Resistance" genes and later by transcripts of "Detoxification" and "Pathogen Defense" mechanisms. A subset of highly over-expressed genes, with putative drug resistance/detoxification roles or Ca²⁺-dependant/modulatory functions, were validated by qPCR. The leading candidate among these was CamKII, a putative calcium/calmodulin-dependent protein kinase type II delta chain. RNA interference was employed to knockdown CamKII in S. japonicum to determine the role of CamKII in the response to praziquantel. After partial-knockdown, schistosomes were analysed using IC₅₀ concentrations (50% worm motility) and quantitative monitoring of parasite movement. When CamKII transcription was reduced by 50-69% in S. japonicum, the subsequent effect of an IC₅₀ dosage of praziquantel was exacerbated, reducing motility from 47% to 27% in female worms and from 61% to 23% in males. These observations indicated that CamKII mitigates the effects of praziquantel, probably through stabilising Ca²⁺ fluxes within parasite muscles and tegument. Together, these studies comprehensively charted transcriptional changes upon exposure to praziquantel and, notably, identified CamKII as potentially central to the, as yet undefined, mode of action of praziquantel.

Item ID: 28323
Item Type: Article (Research - C1)
ISSN: 1553-7374
Additional Information:

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.

Funders: Work is supported by the National Health and Medical Research Council of Australia (496600 NHMRC). DPM is a NHMRC Senior Principal Research Fellow. The funders had no role in study design, data collection and analysis, decision to publish, or preparation.
Date Deposited: 17 Jul 2013 05:27
FoR Codes: 11 MEDICAL AND HEALTH SCIENCES > 1108 Medical Microbiology > 110803 Medical Parasitology @ 50%
06 BIOLOGICAL SCIENCES > 0603 Evolutionary Biology > 060307 Host-Parasite Interactions @ 40%
06 BIOLOGICAL SCIENCES > 0601 Biochemistry and Cell Biology > 060109 Proteomics and Intermolecular Interactions (excl Medical Proteomics) @ 10%
SEO Codes: 92 HEALTH > 9201 Clinical Health (Organs, Diseases and Abnormal Conditions) > 920109 Infectious Diseases @ 60%
97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 30%
97 EXPANDING KNOWLEDGE > 970110 Expanding Knowledge in Technology @ 10%
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