Anti-Acanthamoeba Activity of Brominated Sesquiterpenes from Laurencia johnstonii

Focusedonourinteresttodevelopnovelantiparasisticagents,thepresentstudywasaimed to evaluate the biological activity of an extract of Laurencia johnstonii collected in Baja California Sur, Mexico, against an Acantamoeba castellanii Neff strain. Bioassay-guided fractionation allowed us to identify the amoebicidal diastereoisomers α-bromocuparane (4) and α-isobromocuparane (5). Furthermore, bromination of the inactive laurinterol (1) and isolaurinterol (2) yielded four halogenated derivatives, (6)–(9), which improved the activity of the natural sesquiterpenes. Among them, the most active compound was 3α-bromojohnstane (7), a sesquiterpene derivative which possesses a novel carbon skeleton johnstane

First Report of Vermamoeba vermiformis in the Island of El Hierro, Canary Islands, Spain

Background: Free-living amoebae (FLA) are group of protozoa distributed worldwide in many habitats mainly water and soil related sources. Some members of FLA are able to act as opportunistic pathogens and are environmental carriers of other pathogenic agents such as bacteria and viruses. Vermamoeba vermiformis is a highly abundant FLA species in water bodies and has recently gained environmental importance as it acts as a vehicle of many pathogenic bacteria such as Legionella pneumophila.Cases Report: In this study, water samples were collected from the island of El Hierro, Canary Islands, Spain during 2015. El Hierro island was designated by UNESCO as a biosphere reserve and it is currently the less populated of the Canary Islands. The water samples were culture on 2 % Non-Nutrient Agar (NNA) plates covered with a thin layer of heat killed E. coli and checked daily for the presence of FLA. After a week, V. vermiformis amoebae were observed in the plates incubated at room temperature and 37 ºC. Molecular characterization was carried out by amplifying the 18S rDNA gene and DNA sequencing, confirming that the isolated strain belonged to Vermamoeba vermiformis species.Conclusion: To the best of our knowledge, this is the first report of Vermamoeba vermiformis isolation in the island of El Hierro and the second report of this species in the Canary Islands

Naphthyridine Derivatives Induce Programmed Cell Death in Naegleria fowleri

Primary amoebic encephalitis (PAM) caused by the opportunistic pathogen Naegleria fowleri is characterized as a rapid and lethal infection of the brain which ends in the death of the patient in more than 90% of the reported cases. This amoeba thrives in warm water bodies and causes infection after individuals perform risky activities such as splashing or diving, mostly in non-treated water bodies such as lakes and ponds. Moreover, the infection progresses very fast and no fully effective molecules have currently been found to treat PAM. In this study, naphthyridines fused with chromenes or chromenones previously synthetized by the group were tested in vitro against the trophozoite stage of two strains of N. fowleri. In addition, the most active molecule was evaluated in order to check the induction of programmed cell death (PCD) in the treated amoebae. Compound 3 showed good anti-Naegleria activity (61.45 ± 5.27 and 76.61 ± 10.84 µM, respectively) against the two different strains (ATCC® 30808 and ATCC® 30215) and a good selectivity compared to the cytotoxicity values (>300 µM). In addition, it was able to induce PCD, causing DNA condensation, damage at the cellular membrane, reduction in mitochondrial membrane potential and ATP levels, and ROS generation. Hence, naphthyridines fused with chromenes or chromenones could be potential therapeutic agents against PAM in the near future.This work was funded by PI18/01380 from the Instituto de Salud Carlos III, Spain; RICET (project RD16/0027/0001) from the Programa Redes Temáticas de Investigación Cooperativa, FIS (Ministerio Español de Salud, Madrid, Spain); and CB21/13/00100 Consorcio Centro De Investigacion Biomedica En Red M.P. (CIBER) de Enfermedades Infecciosas, Inst. de Salud Carlos III, Madrid, Spain. A.R.L. and I.A.J. were funded by the Agencia Canaria de Investigación, Innovación y Sociedad de la Información (ACIISI). Additionally, financial support from the Ministerio de Ciencia, Innovación y Universidades (MCIU), Agencia Estatal de Investigación (AEI), and Fondo Europeo de Desarrollo Regional (FEDER; RTI2018-101818-B-I00, UE) and from Gobierno Vasco, Universidad del País Vasco (GV, IT 992-16; UPV) is gratefully acknowledged. Technical and human support provided by IZO-SGI, SGIker (UPV/EHU, MICINN, GV/EJ, ERDF, and ESF) is gratefully acknowledged

Gongolarones as antiamoeboid chemical scaffold

Free Living Amoeba (FLA) infections caused by Acanthamoeba genus include chronic nervous system diseases such as Granulomatous Amoebic Encephalitis (GAE), or a severe eye infection known as Acanthamoeba keratitis (AK). Current studies focused on therapy against these diseases are aiming to find novel compounds with amoebicidal activity and low toxicity to human tissues. Brown algae, such as Gongolaria abies-marina (previously known as Cystoseira abies-marina, S.G. Gmelin), presents bioactive molecules of interest, including some with antiprotozoal activity. In this study, six meroterpenoids were isolated and purified from the species Gongolaria abies-marina. Gongolarones A (1), B (2) and C (3) were identified as new compounds. Additionally, cystomexicone B (4), 1′-methoxyamentadione (5) and 6Z-1′-methoxyamentadione (6) were isolated. All compounds exhibited amoebicidal activity against Acanthamoeba castellanii Neff, A. polyphaga and A. griffini strains. Gongolarones A (1) and C (3) showed the lowest IC50 values against the two stages of these amoebae (trophozoite and cyst). Structure-activity relationship revealed that the cyclization by ether formation from C-12 to C-15 of 1, and the isomerization Δ2 t to Δ3 t of 3, increased the antiamoeboid activity of both compounds. Furthermore, gongolarones A (1) and C (3) triggered chromatin condensation, mitochondrial malfunction, oxidative stress, and disorganization of the tubulin-actin cytoskeleton in treated trophozoites. Moreover, transmission electron microscopy (TEM) images analysis revealed that compounds 1 and 3 induced autophagy process and inhibited the encystation process. All those results suggest that both compounds could induce programmed cell death (PCD) in Acanthamoeba.This study was supported funded by projects PID2019-109476RB-C21 (BIOALGRI) (Spanish Ministry of Science), Madrid, Spain; Fundación CajaCanarias–Fundación Bancaria “La Caixa” (2019SP52). Red de Investigación Cooperativa en Enfermedades Tropicales (RICET), Spain (project no. RD16/0027/0001 of the programe of Redes Temáticas de Investigación Cooperativa, FIS). Consorcio Centro de Investigación Biomédica en Red (CIBER), Área de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, 28029, Madrid, Spain (CB21/13/00100). Project No. 21/0587 funded by the Cabildo de Tenerife, Tenerife innova, Marco Estratégico de Desarrollo Insular (MEDI) and Fondo de Desarrollo de Canarias (FDCAN). Project number ProID2021010118 funded by Agencia Canaria de Investigación, Innovación y Sociedad de la Información (ACIISI). RLRE was funded by a grant from ACIISI cofunded by Fondo Social Europeo (FSE) and FEDER, (TESIS2020010117). MOM was supported by the Programa de Apoyos para la Superación del Personal Académico de la UNAM (PASPA 2021) for carrying out the research stay between the Universidad de La Laguna and la Facultad de Estudios Superiores Iztacala.Peer reviewe

New Insights in <i>Acanthamoeba</i>

Acanthamoeba is a free-living amoeba genus able to cause severe infections, such as Granulomatous amoebic encephalitis (GAE), epithelial disorders and a sight-threatening disease called Acanthamoeba keratitis (AK) [...

Combined Amoebicidal Effect of Atorvastatin and Commercial Eye Drops against Acanthamoeba castellanii Neff: In Vitro Assay Based on Mixture Design

The establishment of an effective therapeutic agent against Acanthamoeba keratitis (AK), remains until present, an issue to be solved due to the existence of a cyst stage in the life cycle of Acanthamoeba. Moreover, the effectiveness of the current standard therapeutic agents varies depending on the tested Acanthamoeba strains and its resistance pattern. In the present study, two 10-point augmented simplex-centroid designs were used to formulate a three-component mixture system using water, atorvastatin, and Diclofenaco-lepori or Optiben. The amoebicidal effects and in vitro-induced toxicity in a eukaryotic cell line were determined for all experiments. The optimal mixture to inhibit the parasite without inducing toxicity was established in the first plan as 30% Optiben, 63.5% atorvastatin, and 3.1% water. As for the second experimental design, the optimal mixture to inhibit Acanthamoeba with lower toxicity effect was composed of 17.6% Diclofenaco-lepori and 82.4% atorvastatin

Statins Induce Actin Cytoskeleton Disassembly and an Apoptosis-Like Process in <i>Acanthamoeba</i> spp.

Acanthamoeba is a ubiquitous opportunistic protozoan pathogen that is known to cause blinding keratitis and rare, but usually fatal, granulomatous encephalitis. The difficulty in treating infections and the toxicity issues of the current treatments emphasize the need to use alternative agents with amoebicidal activity. The aim of this study was to evaluate the in vitro antiamoebic activity of three third-generation statins—cerivastatin, pitavastatin and rosuvastatin—against both cysts and trophozoites of the following four strains of Acanthamoeba: A. castellanii Neff, A. polyphaga, A. griffini and A. quina. Furthermore, programmed cell death (PCD) induction traits were evaluated by measuring chromatin condensation, damages at the mitochondrial level, production of reactive oxygen species (ROS) and the distribution of actin cytoskeleton fibers. Acanthamoeba castellanii Neff was the strain most sensitive to all the statins, where cerivastatin showed the lowest amoebicidal activity for both trophozoite and cyst forms (0.114 ± 0.050 and 0.704 ± 0.129 µM, respectively). All the statins were able to cause DNA condensation, collapse in the mitochondrial membrane potential and a reduction in ATP level production, and disorganization of the total actin fibers in the cytoskeleton of all the evaluated Acanthamoeba strains. Our results showed that the tested statins were able to induce PCD compatible events in the treated amoebae, including chromatin condensation, collapse in the mitochondrial potential and ATP levels, cytoskeleton disassembly and ROS generation

Effect of a Commercial Disinfectant CLORICAN® on Acanthamoeba spp. and Naegleria fowleri Viability

Swimming pool water treatment by chemicals is an essential step to avoid microbial proliferation and infections namely caused by free living amoeba such as, for example, primary amebic meningoencephalitis and Acanthamoeba keratitis. In the present study, a commercial reactive, CLORICAN, based on chlorine dioxide, was evaluated against Acanthamoeba spp. and Naegleria fowleri. We observed that CLORICAN could eliminate in a short period of incubation time both amoebae. Furthermore, Naegleria fowleri’s trophozoites were more sensitive than those of Acanthamoeba spp. By means of inverted microscopy, the chlorine dioxide was found to greatly affect morphology shape by increasing the cell size shrinkage