An in vitro study on the differentiated metabolic mechanism of chloroquine-resistant Plasmodium falciparum using high-resolution metabolomics

ABSTRACT

Chloroquine (CQ) is an important drug used therapeutically for treatment of malaria. However, due to limited number of studies on metabolic targets of chloroquine (CQ), it is difficult to attribute mechanisms underlying resistance associated with usage of this drug. The present study aimed to investigate the metabolic signatures of CQ-resistant Plasmodium falciparum (PfDd2) compared to CQ-sensitive Plasmodium falciparum (Pf3D7). Both Pf3D7 and PfDd2 were treated with CQ at 200 nM for 48 hr; thereafter, the harvested red blood cells (RBCs) and media were subjected to microscopy and high-resolution metabolomics (HRM). Glutathione, γ-L-glutamyl-L-cysteine, spermidine, inosine monophosphate, alanine, and fructose-1,6-bisphosphate were markedly altered in PfDd2 of RBC. In the media, cysteine, cysteic acid, spermidine, phenylacetaldehyde, and phenylacetic acid were significantly altered in PfDd2. These differential metabolic signatures related signaling pathways of PfDd2, such as oxidative stress pathway and glycolysis may provide evidence for understanding the resistance mechanism and pathogenesis of the CQ-resistant parasite.

KEYWORDS:

• Malaria
• chloroquine
• resistance
• red blood cells
• high resolution metabolomics

Acknowledgments

The authors thank Dr. Karan Uppal and Dr. Shuzhao Li from the Emory University School of Medicine (Atlanta, GA, USA) for providing the R-package used to run the apLCMS and xMSannotator. The author declare that Prof. Eun-Taek Han provided PfDd2 and Pf3D7 strains.

Disclosure statement

The authors declare no competing financial interest.

The authors declare that they have no conflict of interest.

Ethical statements

This study was reviewed and approved by the Korea University Guro Hospital (Approval Number 2016GR0793) and was performed in accordance with the guidelines of the Ethical Committee of the Korea University Guro Hospital.

Data availability

The data used in this report is available to readers.

Software availability

The software used in this report is available to readers.

Informed consent

All the patients included in this study provided informed consent.

Author contributions

J. H. N designed the project, established the experimental protocols, and wrote the main manuscript. Y.L.C collected human samples. J. Z provided data analysis and final manuscript. C. S. L and Y. H. P supervised the entire project.

Additional information

Funding

This work was supported by the National Research Foundation of Korea (Grant Numbers NRF-2017R1A2B4003890, NRF-2017M3A9F1031229, and NRF-2020R1A2C2103067).