Transcriptional changes in Toxoplasma gondii in response to treatment with monensin

Bintao Zhai,Xing-Quan Zhu,Xiaoye Yang,Hany M Elsheikha,Jun-Jun He,Jie-Xi Li

doi:10.1186/s13071-020-3970-1

Abstract

BackgroundInfection with the apicomplexan protozoan parasite T. gondii can cause severe and potentially fatal cerebral and ocular disease, especially in immunocompromised individuals. The anticoccidial ionophore drug monensin has been shown to have anti-Toxoplasma gondii properties. However, the comprehensive molecular mechanisms that underlie the effect of monensin on T. gondii are still largely unknown. We hypothesized that analysis of T. gondii transcriptional changes induced by monensin treatment can reveal new aspects of the mechanism of action of monensin against T. gondii.MethodsPorcine kidney (PK)-15 cells were infected with tachyzoites of T. gondii RH strain. Three hours post-infection, PK-15 cells were treated with 0.1 μM monensin, while control cells were treated with medium only. PK-15 cells containing intracellular tachyzoites were harvested at 6 and 24 h post-treatment, and the transcriptomic profiles of T. gondii-infected PK-15 cells were examined using high-throughput RNA sequencing (RNA-seq). Quantitative real-time PCR was used to verify the expression of 15 differentially expressed genes (DEGs) identified by RNA-seq analysis.ResultsA total of 4868 downregulated genes and three upregulated genes were identified in monensin-treated T. gondii, indicating that most of T. gondii genes were suppressed by monensin. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of T. gondii DEGs showed that T. gondii metabolic and cellular pathways were significantly downregulated. Spliceosome, ribosome, and protein processing in endoplasmic reticulum were the top three most significantly enriched pathways out of the 30 highly enriched pathways detected in T. gondii. This result suggests that monensin, via down-regulation of protein biosynthesis in T. gondii, can limit the parasite growth and proliferation.ConclusionsOur findings provide a comprehensive insight into T. gondii genes and pathways with altered expression following monensin treatment. These data can be further explored to achieve better understanding of the specific mechanism of action of monensin against T. gondii.

Highlights

Infection with the apicomplexan protozoan parasite T. gondii can cause severe and potentially fatal cer‐ ebral and ocular disease, especially in immunocompromised individuals
A total of 4868 downregulated genes and three upregulated genes were identified in monensin-treated T. gondii, indicating that most of T. gondii genes were suppressed by monensin
Our findings provide a comprehensive insight into T. gondii genes and pathways with altered expres‐ sion following monensin treatment

Summary

Introduction

Infection with the apicomplexan protozoan parasite T. gondii can cause severe and potentially fatal cer‐ ebral and ocular disease, especially in immunocompromised individuals. The first-line therapy for T. gondii infection is a combination of pyrimethamine and sulfadiazine This regimen has some limitations because these drugs must be taken for a long duration, often cause side effects, and are incapable of eliminating the latent infection [11]. These drawbacks pose a major obstacle in conventional chemotherapy of toxoplasmosis in humans. To this end, efforts have been made to identify new and more effective medicines [12, 13] and to understand the mechanism of action [14] and perturbation associated with the currently used drugs [15]

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