Induction of Programmed Cell Death in Acanthamoeba culbertsoni by the Repurposed Compound Nitroxoline

Abstract

Acanthamoeba is a ubiquitous genus of amoebae that can act as opportunistic parasites in both humans and animals, causing a variety of ocular, nervous and dermal pathologies. Despite advances in Acanthamoeba therapy, the management of patients with Acanthamoeba infections remains a challenge for health services. Therefore, there is a need to search for new active substances against Acanthamoebae. In the present study, we evaluated the amoebicidal activity of nitroxoline against the trophozoite and cyst stages of six different strains of Acanthamoeba. The strain A. griffini showed the lowest IC50 value in the trophozoite stage (0.69 ± 0.01 µM), while the strain A. castellanii L-10 showed the lowest IC50 value in the cyst stage (0.11 ± 0.03 µM). In addition, nitroxoline induced in treated trophozoites of A. culbertsoni features compatibles with apoptosis and autophagy pathways, including chromatin condensation, mitochondrial malfunction, oxidative stress, changes in cell permeability and the formation of autophagic vacuoles. Furthermore, proteomic analysis of the effect of nitroxoline on trophozoites revealed that this antibiotic induced the overexpression and the downregulation of proteins involved in the apoptotic process and in metabolic and biosynthesis pathways.

Amoebicidal Effect of COVID Box Molecules against Acanthamoeba: A Study of Cell Death

“…Based on the amoebicidal and cytotoxicity results, the selected compounds, Almitrine and Terconazole, were further investigated on the cyst stage of the various Acanthamoeba strains: A. castellanii Neff, A. griffini, A. polyphaga, A. culbertsoni , and A. castellanii L-10. The cysticidal activity was assessed by the alamarBlue™ method, as described previously [ 38 ]. Briefly, in a 96-well plate, a serial dilution of the mentioned drugs was first conducted.…”

“…A double-stain apoptosis detection kit (Chromatin Condensation/Dead Cell Apoptosis Kit) with Hoechst 33342 and Propidium Iodide (Invitrogen, Madrid, Spain) were used. The experiment was carried out by following the manufacturer’s recommendations [ 38 ].…”

“…Briefly, 105 trophozoites were incubated for 24 h with IC 90 of the drug solution. Subsequently, the SYTOX ® Green dye was added at a final concentration of 1 μM for 15 min in the dark [ 38 ].…”

“…Based on the JC-1 state and the emitted fluorescence, we distinguished two sets in the cellular population: live cells emit high red fluorescence and affected cells with collapsed mitochondrial membrane potential emit a higher green fluorescence [ 38 ].…”

Staurosporine as a potential treatment for Acanthamoeba keratitis using mouse cornea as an ex vivo model

“…Comparative label-free proteomic analysis was conducted described in our recent study [17]. 10 6 cells of A. castellanii were treated with the IC 50 of Staurosporine for 24 hours, washed 1 time with PBS and the pellets were subjected to further processing.…”