Enhanced antiamoebic efficacy of PHMB via methyltransferase inhibition to maintain drug sensitivity and block encystation.
6 affiliations
- 1Department of Medical Science, College of Life Sciences and Medicine, National Tsing Hua University, Hsinchu, Taiwan.
- 2Institute of Molecular and Cellular Biology, College of Life Sciences and Medicine, National Tsing Hua University, Hsinchu, Taiwan.
- 3Department of Parasitology, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
- 4Department of Medical Science, College of Life Sciences and Medicine, National Tsing Hua University, Hsinchu, Taiwan. [email protected].
- 5Institute of Molecular and Cellular Biology, College of Life Sciences and Medicine, National Tsing Hua University, Hsinchu, Taiwan. [email protected].
- 6School of Medicine, College of Life Sciences and Medicine, National Tsing Hua University, Hsinchu, Taiwan. [email protected].
Abstract
Background
Acanthamoeba keratitis (AK) is a severe ocular infection. The primary treatment is polyhexamethylene biguanide (PHMB), but its efficacy is limited due to cyst resistance. This study investigated the role of DNA methylation in Acanthamoeba encystation and the potential efficacy of combining 5-azacytidine (5-AzaC; a methyltransferase inhibitor) with PHMB treatment.Methods
Encystation was induced in Acanthamoeba castellanii using encystation buffer, followed by calcofluor white staining. Gene expression levels of virulence genes and the methyltransferase gene were assessed by quantitative PCR. The cell viability assay of A. castellanii on Statens Seruminstitut Rabbit Cornea (SIRC) cells was evaluated to determine functional virulence. Overexpression of methyltransferase via electroporation was established to further investigate its function.Results
qPCR results revealed upregulated methyltransferase expression during encystation. Calcofluor white staining showed significantly reduced cyst formation in A. castellanii treated with 5-AzaC. This treatment also induced significant transcriptional reduction in virulence genes. Consistently, 5-AzaC-treated A. castellanii did not exhibit increased cytotoxicity against SIRC cells. Overexpression of the methyltransferase increases the encystation ratio. Combination treatment with PHMB and 5-AzaC significantly decreased A. castellanii survival.Conclusions
Inhibiting DNA methylation enhances the antiamoebic effects of PHMB, offering a potential AK treatment strategy. DNA methylation may serve as a critical regulatory switch in A. castellanii, governing both morphological transformation and virulence genes expression. This work expands our understanding of epigenetic regulation in protozoa.
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BibTeX
@article{wu2026enhanced,
title = {{Enhanced antiamoebic efficacy of PHMB via methyltransferase inhibition to maintain drug sensitivity and block encystation.}},
author = {Jui-Chi Wu and Chun-Hsien Chen and Jian-Ming Huang},
journal = {Parasites \& vectors},
year = {2026},
month = aug,
doi = {10.1186/s13071-026-07597-6},
url = {https://europepmc.org/article/MED/42958428},
note = {CC BY},
}
RIS
TY - JOUR
TI - Enhanced antiamoebic efficacy of PHMB via methyltransferase inhibition to maintain drug sensitivity and block encystation.
AU - Jui-Chi Wu
AU - Chun-Hsien Chen
AU - Jian-Ming Huang
PY - 2026
DA - 2026/08/04
JO - Parasites & vectors
DO - 10.1186/s13071-026-07597-6
UR - https://europepmc.org/article/MED/42958428
AB - Background Acanthamoeba keratitis (AK) is a severe ocular infection. The primary treatment is polyhexamethylene biguanide (PHMB), but its efficacy is limited due to cyst resistance. This study investigated the role of DNA methylation in Acanthamoeba encystation and the potential efficacy of combining 5-azacytidine (5-AzaC; a methyltransferase inhibitor) with PHMB treatment.Methods Encystation was induced in Acanthamoeba castellanii using encystation buffer, followed by calcofluor white staining. Gene expression levels of virulence genes and the methyltransferase gene were assessed by quantitative PCR. The cell viability assay of A. castellanii on Statens Seruminstitut Rabbit Cornea (SIRC) cells was evaluated to determine functional virulence. Overexpression of methyltransferase via electroporation was established to further investigate its function.Results qPCR results revealed upregulated methyltransferase expression during encystation. Calcofluor white staining showed significantly reduced cyst formation in A. castellanii treated with 5-AzaC. This treatment also induced significant transcriptional reduction in virulence genes. Consistently, 5-AzaC-treated A. castellanii did not exhibit increased cytotoxicity against SIRC cells. Overexpression of the methyltransferase increases the encystation ratio. Combination treatment with PHMB and 5-AzaC significantly decreased A. castellanii survival.Conclusions Inhibiting DNA methylation enhances the antiamoebic effects of PHMB, offering a potential AK treatment strategy. DNA methylation may serve as a critical regulatory switch in A. castellanii, governing both morphological transformation and virulence genes expression. This work expands our understanding of epigenetic regulation in protozoa.
SN - 1756-3305
ER -