Influential Parameters for the Analysis of Intracellular Parasite Metabolomics

ABSTRACT Metabolomics is increasingly popular for the study of pathogens. For the malaria parasite Plasmodium falciparum, both targeted and untargeted metabolomics have improved our understanding of pathogenesis, host-parasite interactions, and antimalarial drug treatment and resistance. However, pu...

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Autores principales: Maureen A. Carey, Vincent Covelli, Audrey Brown, Gregory L. Medlock, Mareike Haaren, Jessica G. Cooper, Jason A. Papin, Jennifer L. Guler
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Publicado: American Society for Microbiology 2018
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spelling oai:doaj.org-article:9e4f3c0e95484af38850c730c8cbdcf22021-11-15T15:22:14ZInfluential Parameters for the Analysis of Intracellular Parasite Metabolomics10.1128/mSphere.00097-182379-5042https://doaj.org/article/9e4f3c0e95484af38850c730c8cbdcf22018-04-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mSphere.00097-18https://doaj.org/toc/2379-5042ABSTRACT Metabolomics is increasingly popular for the study of pathogens. For the malaria parasite Plasmodium falciparum, both targeted and untargeted metabolomics have improved our understanding of pathogenesis, host-parasite interactions, and antimalarial drug treatment and resistance. However, purification and analysis procedures for performing metabolomics on intracellular pathogens have not been explored. Here, we purified in vitro-grown ring-stage intraerythrocytic P. falciparum parasites for untargeted metabolomics studies; the small size of this developmental stage amplifies the challenges associated with metabolomics studies as the ratio between host and parasite biomass is maximized. Following metabolite identification and data preprocessing, we explored multiple confounding factors that influence data interpretation, including host contamination and normalization approaches (including double-stranded DNA, total protein, and parasite numbers). We conclude that normalization parameters have large effects on differential abundance analysis and recommend the thoughtful selection of these parameters. However, normalization does not remove the contribution from the parasite’s extracellular environment (culture media and host erythrocyte). In fact, we found that extraparasite material is as influential on the metabolome as treatment with a potent antimalarial drug with known metabolic effects (artemisinin). Because of this influence, we could not detect significant changes associated with drug treatment. Instead, we identified metabolites predictive of host and medium contamination that could be used to assess sample purification. Our analysis provides the first quantitative exploration of the effects of these factors on metabolomics data analysis; these findings provide a basis for development of improved experimental and analytical methods for future metabolomics studies of intracellular organisms. IMPORTANCE Molecular characterization of pathogens such as the malaria parasite can lead to improved biological understanding and novel treatment strategies. However, the distinctive biology of the Plasmodium parasite, including its repetitive genome and the requirement for growth within a host cell, hinders progress toward these goals. Untargeted metabolomics is a promising approach to learn about pathogen biology. By measuring many small molecules in the parasite at once, we gain a better understanding of important pathways that contribute to the parasite’s response to perturbations such as drug treatment. Although increasingly popular, approaches for intracellular parasite metabolomics and subsequent analysis are not well explored. The findings presented in this report emphasize the critical need for improvements in these areas to limit misinterpretation due to host metabolites and to standardize biological interpretation. Such improvements will aid both basic biological investigations and clinical efforts to understand important pathogens.Maureen A. CareyVincent CovelliAudrey BrownGregory L. MedlockMareike HaarenJessica G. CooperJason A. PapinJennifer L. GulerAmerican Society for MicrobiologyarticlePlasmodium falciparumapicomplexan parasitesintracellular pathogenmetabolomicsMicrobiologyQR1-502ENmSphere, Vol 3, Iss 2 (2018)
institution DOAJ
collection DOAJ
language EN
topic Plasmodium falciparum
apicomplexan parasites
intracellular pathogen
metabolomics
Microbiology
QR1-502
spellingShingle Plasmodium falciparum
apicomplexan parasites
intracellular pathogen
metabolomics
Microbiology
QR1-502
Maureen A. Carey
Vincent Covelli
Audrey Brown
Gregory L. Medlock
Mareike Haaren
Jessica G. Cooper
Jason A. Papin
Jennifer L. Guler
Influential Parameters for the Analysis of Intracellular Parasite Metabolomics
description ABSTRACT Metabolomics is increasingly popular for the study of pathogens. For the malaria parasite Plasmodium falciparum, both targeted and untargeted metabolomics have improved our understanding of pathogenesis, host-parasite interactions, and antimalarial drug treatment and resistance. However, purification and analysis procedures for performing metabolomics on intracellular pathogens have not been explored. Here, we purified in vitro-grown ring-stage intraerythrocytic P. falciparum parasites for untargeted metabolomics studies; the small size of this developmental stage amplifies the challenges associated with metabolomics studies as the ratio between host and parasite biomass is maximized. Following metabolite identification and data preprocessing, we explored multiple confounding factors that influence data interpretation, including host contamination and normalization approaches (including double-stranded DNA, total protein, and parasite numbers). We conclude that normalization parameters have large effects on differential abundance analysis and recommend the thoughtful selection of these parameters. However, normalization does not remove the contribution from the parasite’s extracellular environment (culture media and host erythrocyte). In fact, we found that extraparasite material is as influential on the metabolome as treatment with a potent antimalarial drug with known metabolic effects (artemisinin). Because of this influence, we could not detect significant changes associated with drug treatment. Instead, we identified metabolites predictive of host and medium contamination that could be used to assess sample purification. Our analysis provides the first quantitative exploration of the effects of these factors on metabolomics data analysis; these findings provide a basis for development of improved experimental and analytical methods for future metabolomics studies of intracellular organisms. IMPORTANCE Molecular characterization of pathogens such as the malaria parasite can lead to improved biological understanding and novel treatment strategies. However, the distinctive biology of the Plasmodium parasite, including its repetitive genome and the requirement for growth within a host cell, hinders progress toward these goals. Untargeted metabolomics is a promising approach to learn about pathogen biology. By measuring many small molecules in the parasite at once, we gain a better understanding of important pathways that contribute to the parasite’s response to perturbations such as drug treatment. Although increasingly popular, approaches for intracellular parasite metabolomics and subsequent analysis are not well explored. The findings presented in this report emphasize the critical need for improvements in these areas to limit misinterpretation due to host metabolites and to standardize biological interpretation. Such improvements will aid both basic biological investigations and clinical efforts to understand important pathogens.
format article
author Maureen A. Carey
Vincent Covelli
Audrey Brown
Gregory L. Medlock
Mareike Haaren
Jessica G. Cooper
Jason A. Papin
Jennifer L. Guler
author_facet Maureen A. Carey
Vincent Covelli
Audrey Brown
Gregory L. Medlock
Mareike Haaren
Jessica G. Cooper
Jason A. Papin
Jennifer L. Guler
author_sort Maureen A. Carey
title Influential Parameters for the Analysis of Intracellular Parasite Metabolomics
title_short Influential Parameters for the Analysis of Intracellular Parasite Metabolomics
title_full Influential Parameters for the Analysis of Intracellular Parasite Metabolomics
title_fullStr Influential Parameters for the Analysis of Intracellular Parasite Metabolomics
title_full_unstemmed Influential Parameters for the Analysis of Intracellular Parasite Metabolomics
title_sort influential parameters for the analysis of intracellular parasite metabolomics
publisher American Society for Microbiology
publishDate 2018
url https://doaj.org/article/9e4f3c0e95484af38850c730c8cbdcf2
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