<i>Acanthamoeba culbertsoni</i>: Electron‐Dense Granules in a Highly Virulent Clinical Isolate

Chávez‐Munguía, Bibiana; Salazar‐Villatoro, Lizbeth; Omaña‐Molina, Maritza; Espinosa‐Cantellano, Martha; Ramírez-Flores, Elizabeth; Lorenzo‐Morales, Jacob; Martı́nez-Palomo, Adolfo

doi:10.1111/jeu.12321

Cited by 7 publications

(3 citation statements)

References 46 publications

(86 reference statements)

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“…Thin sections of 60 nm were obtained and stained with uranyl acetate and subsequently incubated with sodium citrate. Then, the samples were mounted on slides and were observed in a JEOL-JEM-1011 transmission electron microscope (JEOL Ltd. Tokyo, Japan) …”

Section: Methodsmentioning

confidence: 99%

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Linearolactone and Kaempferol Disrupt the Actin Cytoskeleton in Entamoeba histolytica: Inhibition of Amoebic Liver Abscess Development

et al. 2020

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Linearolactone (1) and kaempferol (2) have amebicidal activity in in vitro studies. The type of cell death induced by 1 and 2 and their effects on the virulence of E. histolytica were analyzed by transmission and confocal electron microscopy, reactive oxygen species (ROS) production, and apoptosis, detected by flow cytometry with dichlorofluorescein 2′,7′-diacetate and annexin-V binding, respectively, and confirmed by TUNEL. The interaction of 1 and 2 with actin was analyzed by docking, and the in vivo amoebicidal activity was established with the Mesocricetus auratus model; amebic liver abscess (ALA) development was evaluated by magnetic resonance (MR) and validated post mortem. In vitro, compounds 1 and 2 caused chromatin condensation, intracellular ROS, and loss of actin structures. Coupling analysis showed that they bind to the allosteric and catalytic sites of actin with binding energies of −11.30 and −8.45 kcal/mol, respectively. Treatments with 1 and 2 induced a decrease in ALA formation without toxic effects on the liver and kidney. Thus, compound 1, but not 2, was able to induce apoptosis-like effects in E. histolytica trophozoites by intracellular production of ROS that affected the actin cytoskeleton structuration. In vivo, compound 1 was more active than compound 2 to reduce the development of ALA.

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Section: Methodsmentioning

confidence: 99%

“…Then, the samples were mounted on slides and were observed in a JEOL-JEM-1011 transmission electron microscope (JEOL Ltd. Tokyo, Japan). 32 DCFDA Cellular Reactive Oxygen Species Detection Assay. Independent experiments using trophozoites (5 × 10 5 ) treated with the IC 50 of 1 or 2 were processed to detect ROS.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Linearolactone and Kaempferol Disrupt the Actin Cytoskeleton in Entamoeba histolytica: Inhibition of Amoebic Liver Abscess Development

et al. 2020

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“…These proteases could facilitate the invasion of amoebae through cell junctions, without causing their destruction [9]. Furthermore, Chávez-Munguía et al, in 2016, described that A. culbertsoni trophozoites, a highly virulent strain isolated from a clinical case of AK, produces electron-dense granules, which induced the separation of tight junctions when they interacted in vitro with Madin-Darby Canine Kidney (MDCK) cells [28].…”

Section: Introductionmentioning

confidence: 99%

Extracellular Vesicles Secreted by Acanthamoeba culbertsoni Have COX and Proteolytic Activity and Induce Hemolysis

Sierra-López,

Castelan-Ramírez,

Hernández-Martínez

et al. 2023

Microorganisms

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Several species of Acanthamoeba genus are potential pathogens and etiological agents of several diseases. The pathogenic mechanisms carried out by these amoebae in different target tissues have been documented, evidencing the relevant role of contact-dependent mechanisms. With the purpose of describing the pathogenic processes carried out by these protozoans more precisely, we considered it important to determine the emission of extracellular vesicles (EVs) as part of the contact-independent pathogenicity mechanisms of A. culbertsoni, a highly pathogenic strain. Through transmission electronic microscopy (TEM) and nanoparticle tracking analysis (NTA), EVs were characterized. EVs showed lipid membrane and a size between 60 and 855 nm. The secretion of large vesicles was corroborated by confocal and TEM microscopy. The SDS-PAGE of EVs showed proteins of 45 to 200 kDa. Antigenic recognition was determined by Western Blot, and the internalization of EVs by trophozoites was observed through Dil-labeled EVs. In addition, some EVs biological characteristics were determined, such as proteolytic, hemolytic and COX activity. Furthermore, we highlighted the presence of leishmanolysin in trophozites and EVs. These results suggest that EVs are part of a contact-independent mechanism, which, together with contact-dependent ones, allow for a better understanding of the pathogenicity carried out by Acanthamoeba culbertsoni.

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In vivo CNS infection model of Acanthamoeba genotype T4: the early stages of infection lack presence of host inflammatory response and are a slow and contact-dependent process

et al. 2016

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This study was developed in order to describe the early morphological events observed during the invasion of two pathogenic strains of Acanthamoeba (genotype T4); A. castellanii and A. culbertsoni, at the olfactory meatus and cerebral, pulmonary, renal, hepatic and splenic tissues levels, an in vivo invasion study. Histological and immunohistochemical description of the events at 24, 48, 72, and 96 h postintranasal inoculations of BALB/c mice was performed. A. castellanii showed a higher invasion rate than A. culbertsoni, which was only able to reach lung and brain tissue in the in vivo model. The current study supports previous evidence of lack of inflammatory response during the early stages of infection. Acanthamoeba invasion of the CNS and other organs is a slow and contact-dependent process. The early morphological events during the invasion of amoebae include the penetration of trophozoites into different epithelia: olfactory, respiratory, alveolar space, and renal tubule, which resemble the process of amoebae invasion described in corneal tissue. The data suggest that after reaching the nasal epithelium, trophozoites continued invasion, separating and lifting the most superficial cells, then migrating and penetrating between the cell junctions without causing a cytolytic effect on adjacent cells. These results reaffirm the idea that contact-dependent mechanisms are relevant for amoebae of Acanthamoeba genus regardless of the invasion site.

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Acanthamoeba culbertsoni: Electron‐Dense Granules in a Highly Virulent Clinical Isolate

Cited by 7 publications

References 46 publications

Linearolactone and Kaempferol Disrupt the Actin Cytoskeleton in Entamoeba histolytica: Inhibition of Amoebic Liver Abscess Development

Linearolactone and Kaempferol Disrupt the Actin Cytoskeleton in Entamoeba histolytica: Inhibition of Amoebic Liver Abscess Development

Extracellular Vesicles Secreted by Acanthamoeba culbertsoni Have COX and Proteolytic Activity and Induce Hemolysis

In vivo CNS infection model of Acanthamoeba genotype T4: the early stages of infection lack presence of host inflammatory response and are a slow and contact-dependent process

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