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Amoebicidal effect of Antimicrobial Peptides against Acanthamoeba castellanii: A study of cell death using
Ines Sifaoui1, Rubén L Rodríguez-Expósito1, María Reyes-Batlle1
1Instituto Universitario de Enfermedades Tropicales y Salud Pública de Canarias (IUETSPC), Universidad de La Laguna (ULL), Tenerife, Spain; Departamento de Obstetricia y Ginecología, Pediatría, Medicina Preventiva y Salud Pública, Toxicología, Medicina Legal y Forense y Parasitología, Universidad de La Laguna, Tenerife, Spain; Consorcio Centro de investigación biomédica En Red (CIBER), área de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain.
Abstract:
Acanthamoeba infections are hindered by limitations including prolonged treatment duration, cytotoxicity, limited efficacy against the resistant cystic stage, and a high rate of recurrence. Antimicrobial peptides (AMPs) demonstrate broad-spectrum antimicrobial activity, rapid mechanism of action, low potential for inducing resistance, and efficacy against both trophozoite and cyst forms, highlighting their potential as promising alternatives in the treatment of these infections. Herein, we report the amoebicidal activity of various peptides derived from cathelicidins and piscidins against Acanthamoeba castellanii Neff. Afterwards, the impact of the most effective peptide on the clinical features of a clinical strain of Acanthamoeba castellanii was evaluated using a fluorescence imaging system. Peptide OH_KR34 was the most active against A. castellanii Neff with an IC₅₀ values of 2.00 ± 0.58 µM. OH_KR34 was able to inhibit the clinical strain of A. castellanii (L10) with an IC50 of 5.75 ± 0.30 μM. We demonstrated that the peptide OH_KR34 (related to OH-CATH) induces cytoskeletal damage and trigger apoptosis-like process by disrupting cell membrane permeability, mitochondrial dysfunction and DNA fragmentation. This antimicrobial peptide could therefore offer a potential target to develop new anti-parasitic drugs.
Insights
Antimicrobial peptides show promise for treating Acanthamoeba infections. Peptide OH_KR34 effectively killed Acanthamoeba parasites by damaging their cells and triggering apoptosis-like processes.
Area of Science:
- Parasitology
- Drug Discovery
- Biochemistry
Background:
- Acanthamoeba infections present treatment challenges due to drug resistance and recurrence.
- Antimicrobial peptides (AMPs) offer broad-spectrum activity and potential against resistant parasite stages.
Purpose of the Study:
- To evaluate the amoebicidal activity of cathelicidin and piscidin-derived peptides against Acanthamoeba castellanii.
- To investigate the mechanism of action of the most effective peptide on Acanthamoeba parasites.
Main Methods:
- Screening of various AMPs against Acanthamoeba castellanii Neff.
- Evaluation of the most potent peptide (OH_KR34) against a clinical Acanthamoeba strain using fluorescence imaging.
- Analysis of cellular damage, membrane permeability, mitochondrial function, and DNA fragmentation.
Main Results:
- Peptide OH_KR34 exhibited potent amoebicidal activity against both laboratory and clinical strains of Acanthamoeba.
- OH_KR34 demonstrated significant efficacy with IC₅₀ values of 2.00 ± 0.58 µM and 5.75 ± 0.30 μM, respectively.
- The peptide induced cytoskeletal damage, disrupted cell membrane permeability, caused mitochondrial dysfunction, and triggered DNA fragmentation.
Conclusions:
- Antimicrobial peptide OH_KR34 is a promising candidate for developing novel anti-parasitic drugs against Acanthamoeba infections.
- The findings highlight AMPs as a viable alternative to current treatments, addressing limitations like resistance and recurrence.
