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1.
J Fish Dis ; 43(1): 39-48, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31726482

RESUMO

Hydrogen peroxide (H2 O2 ) is a commonly used treatment for a range of parasitic diseases of marine finfish, including amoebic gill disease (AGD). While this treatment is partially effective at reducing parasite load, H2 O2 can have detrimental effects on the host under certain conditions. Treatment temperature and dose concentration are two factors that are known to influence the toxicity of H2 O2 ; however, their impact on the outcome of AGD treatment remains unclear. Here, we investigated the effects of treatment temperature (8, 12 or 16°C) and dose concentration (750, 1,000, 1,250 mg/L) on the efficacy of H2 O2 to treat AGD. We demonstrated that a 20-min bath treatment of H2 O2 at all doses reduced both parasite load and gross gill score significantly. Parasite load and gross gill score were lowest in the 1,000 mg/L treatment performed at 12°C. At the high dose and temperature combinations, H2 O2 caused moderate gill damage and a significant increase in the plasma concentration of electrolytes (sodium, chloride and potassium). Taken together, our study demonstrates that higher H2 O2 treatment temperatures can adversely affect the host and do not improve the effectiveness of the treatment.


Assuntos
Amebíase/veterinária , Antiprotozoários/uso terapêutico , Doenças dos Peixes/tratamento farmacológico , Peróxido de Hidrogênio/uso terapêutico , Salmo salar , Temperatura , Amebíase/tratamento farmacológico , Amebíase/parasitologia , Animais , Relação Dose-Resposta a Droga , Feminino , Doenças dos Peixes/parasitologia , Brânquias/parasitologia
3.
Parasitol Res ; 118(10): 3061-3066, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31502076

RESUMO

The burden of HIV/AIDS in Iran is not as high as in the other countries with high prevalence; however, the number of cases of HIV/AIDs is increasing in this region. According to a recent report, Iran had 5000 (1400-13,000) new cases of HIV infection with 4000 (2500-6200) AIDS-related deaths. Individuals affected by HIV/AIDS are highly susceptible for developing opportunistic infections, e.g. the cerebral complications related to pathogenic free-living amoebae and colonization of free-living amoebae (FLA) can be a serious hazard for patients living with HIV/AIDS. In the present study, a total of 70 oral and nasal mucosal samples were obtained from HIV/AIDS patients referred to the reference hospitals in Iran and tested for the presence of potentially pathogenic FLA using culture and PCR/sequencing-based methods. To discern the taxonomic status of Acanthamoeba genotypes a maximum likelihood phylogenetic tree was constructed and tolerance assays were performed for the positive Acanthamoeba strains. Among the patients with HIV/AIDS referred to the reference hospitals from 2017 to 2019, 7.1% were found positive for pathogenic free-living amoebae. Three strains (HA3, HA4, and HA5) belonged to the T4 genotype, one strain (HA1) was related to the T5 genotype assigned as A. lenticulata, and another strain (HA2) had high homology to Vermamoeba vermiformis. The tolerance assay used for Acanthamoeba strains (HA1, HA3, and HA4) classified these amoebae as highly pathogenic strains. For the most part, the encephalitis cases occurring in HIV/AIDS patients in Iran remain undiagnosed due to lack of awareness of the practitioners on the available diagnostic tools for this lethal infection; therefore, the true incidence of GAE in this region is unknown. A possible colonization with FLA should be considered in the differential diagnosis of suspected cases of CNS infections among HIV/AIDS patients. This study is the first worldwide comprehensive study attempting to isolate and identify the FLA colonization in HIV/AIDS patients. This study highlights the fact that clinicians should be aware of the differential diagnosis of cerebral disease related to FLA in patients with HIV/AIDS.


Assuntos
Infecções Oportunistas Relacionadas com a AIDS/parasitologia , Acanthamoeba/classificação , Acanthamoeba/isolamento & purificação , Amebíase/parasitologia , Mucosa Bucal/parasitologia , Filogenia , Infecções Oportunistas Relacionadas com a AIDS/complicações , Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Acanthamoeba/genética , Acanthamoeba/patogenicidade , Adulto , Idoso , Amebíase/complicações , Amebíase/epidemiologia , Feminino , Genótipo , Humanos , Irã (Geográfico)/epidemiologia , Masculino , Pessoa de Meia-Idade , Mucosa Nasal/parasitologia
4.
Infect Immun ; 87(11)2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31427448

RESUMO

Entamoeba histolytica is an anaerobic parasitic protozoan and the causative agent of amoebiasis. E. histolytica expresses proteins that are structurally homologous to human proteins and uses them as virulence factors. We have previously shown that E. histolytica binds exogenous interferon gamma (IFN-γ) on its surface, and in this study, we explored whether exogenous IFN-γ could modulate parasite virulence. We identified an IFN-γ receptor-like protein on the surface of E. histolytica trophozoites by using anti-IFN-γ receptor 1 (IFN-γR1) antibody and performing immunofluorescence, Western blot, protein sequencing, and in silico analyses. Coupling of human IFN-γ to the IFN-γ receptor-like protein on live E. histolytica trophozoites significantly upregulated the expression of E. histolytica cysteine protease A1 (EhCP-A1), EhCP-A2, EhCP-A4, EhCP-A5, amebapore A (APA), cyclooxygenase 1 (Cox-1), Gal-lectin (Hgl), and peroxiredoxin (Prx) in a time-dependent fashion. IFN-γ signaling via the IFN-γ receptor-like protein enhanced E. histolytica's erythrophagocytosis of human red blood cells, which was abrogated by the STAT1 inhibitor fludarabine. Exogenous IFN-γ enhanced chemotaxis of E. histolytica, its killing of Caco-2 colonic and Hep G2 liver cells, and amebic liver abscess formation in hamsters. These results demonstrate that E. histolytica expresses a surface IFN-γ receptor-like protein that is functional and may play a role in disease pathogenesis and/or immune evasion.


Assuntos
Entamoeba histolytica/metabolismo , Proteínas de Protozoários/metabolismo , Receptores de Interferon/química , Amebíase/imunologia , Amebíase/parasitologia , Animais , Células CACO-2 , Sobrevivência Celular , Cricetinae , Células Hep G2 , Humanos , Interferon gama/farmacologia , Masculino , Fagocitose , Proteínas de Protozoários/química , Proteínas de Protozoários/genética
6.
J Fish Dis ; 42(9): 1241-1258, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31206728

RESUMO

A relationship between increasing water temperature and amoebic gill disease (AGD) prevalence in Atlantic salmon (Salmo salar) has been noted at fish farms in numerous countries. In Scotland (UK), temperatures above 12°C are considered to be an important risk factor for AGD outbreaks. Thus, the purpose of this study was to test for the presence of an association between temperature and variation in the severity of AGD in Atlantic salmon at 10 and 15°C. The results showed an association between temperature and variation in AGD severity in salmon from analysis of histopathology and Paramoeba perurans load, reflecting an earlier and stronger infection post-amoebae exposure at the higher temperature. While no significant difference between the two temperature treatment groups was found in plasma cortisol levels, both glucose and lactate levels increased when gill pathology was evident at both temperatures. Expression analysis of immune- and stress-related genes showed more modulation in gills than in head kidney, revealing an organ-specific response and an interplay between temperature and infection. In conclusion, temperature may not only affect the host response, but perhaps also favour higher attachment/growth capacity of the amoebae as seen with the earlier and stronger P. perurans infection at 15°C.


Assuntos
Amebíase/veterinária , Brânquias/patologia , Temperatura Alta/efeitos adversos , Salmo salar , Amebíase/parasitologia , Amebíase/patologia , Animais , Doenças dos Peixes/parasitologia , Doenças dos Peixes/patologia
8.
Neuropathology ; 39(4): 251-258, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31243796

RESUMO

Over 600 cases of amoebic encephalitis caused by pathogenic free-living amoebas (Balamuthia mandrillaris, Acanthamoeba spp., and Naegleria fowleri) have been reported worldwide, and in Japan, 24 cases have been reported from the first case in 1976 up to 2018. Among these cases, 18 were caused by B. mandrillaris, four by Acanthamoeba spp., one by N. fowleri, and one was of unknown etiology. Additionally, eight cases were diagnosed with encephalitis due to pathogenic free-living amoebas before death, but only three cases were successfully treated. Unfortunately, all other cases were diagnosed by autopsy. These facts indicate that an adequate diagnosis is difficult, because encephalitis due to pathogenic free-living amoebas does not show typical symptoms or laboratory findings. Moreover, because the number of cases is limited, other cases might have been missed outside of those diagnosed by autopsy. Cases of encephalitis caused by B. mandrillaris have been reported from all over Japan, with B. mandrillaris recently isolated from soil in Aomori prefecture. Therefore, encephalitis caused by pathogenic free-living amoebas should be added to the differential diagnosis of encephalitis patients.


Assuntos
Acanthamoeba/fisiologia , Amebíase/parasitologia , Balamuthia mandrillaris/fisiologia , Infecções Protozoárias do Sistema Nervoso Central/parasitologia , Encefalite/parasitologia , Naegleria fowleri/fisiologia , Infecções Protozoárias do Sistema Nervoso Central/diagnóstico , Encefalite/diagnóstico , Humanos , Japão
9.
Drug Resist Updat ; 44: 1-14, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31112766

RESUMO

Entamoeba histolytica is the etiological agent of amebiasis, which is an endemic parasitic disease in developing countries and is the cause of approximately 70,000 deaths annually. E. histolytica trophozoites usually reside in the colon as a non-pathogenic commensal in most infected individuals (90% of infected individuals are asymptomatic). For unknown reasons, these trophozoites can become virulent and invasive, cause amebic dysentery, and migrate to the liver where they cause hepatocellular damage. Amebiasis is usually treated either by amebicides which are classified as (a) luminal and are active against the luminal forms of the parasite, (b) tissue and are effective against those parasites that have invaded tissues, and (c) mixed and are effective against the luminal forms of the parasite and those forms which invaded the host's tissues. Of the amebicides, the luminal amebicide, metronidazole (MTZ), is the most widely used drug to treat amebiasis. Although well tolerated, concerns about its adverse effects and the possible emergence of MTZ-resistant strains of E. histolytica have led to the development of new therapeutic strategies against amebiasis. These strategies include improving the potency of existing amebicides, discovering new uses for approved drugs (repurposing of existing drugs), drug rediscovery, vaccination, drug targeting of essential E. histolytica components, and the use of probiotics and bioactive natural products. This review examines each of these strategies in the light of the current knowledge on the gut microbiota of patients with amebiasis.


Assuntos
Amebíase/tratamento farmacológico , Amebíase/prevenção & controle , Amebicidas/uso terapêutico , Entamoeba histolytica/efeitos dos fármacos , Terapia de Alvo Molecular/métodos , Vacinas Protozoárias/administração & dosagem , Amebíase/imunologia , Amebíase/parasitologia , Animais , Produtos Biológicos/uso terapêutico , Colo/efeitos dos fármacos , Colo/parasitologia , Colo/patologia , Reposicionamento de Medicamentos/métodos , Entamoeba histolytica/patogenicidade , Entamoeba histolytica/fisiologia , Microbioma Gastrointestinal/imunologia , Interações Hospedeiro-Parasita/imunologia , Humanos , Fígado/efeitos dos fármacos , Fígado/parasitologia , Fígado/patologia , Metronidazol/uso terapêutico , Interações Microbianas , Probióticos/uso terapêutico , Vacinas Protozoárias/biossíntese , Índice de Gravidade de Doença
10.
Parasitol Res ; 118(6): 1865-1874, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31065830

RESUMO

Acanthamoeba is a free-living pathogenic protozoan that is distributed in different environmental reservoirs, including lakes and soil. Pathogenic Acanthamoeba can cause severe human diseases, such as blinding keratitis and granulomatous encephalitis. Therefore, it is important to understand the pathogenic relationship between humans and Acanthamoeba. By comparison of systemic analysis results for Acanthamoeba isolates, we identified a novel secreted protein of Acanthamoeba, an M28 aminopeptidase (M28AP), which targets of the human innate immune defense. We investigated the molecular functions and characteristics of the M28AP protein by anti-M28 antibodies and a M28AP mutant strain generated by the CRISPR/Cas9 system. Human complement proteins such as C3b and iC3b were degraded by Acanthamoeba M28AP. We believe that M28AP is an important factor in human innate immunity. This study provides new insight for the development of more efficient medicines to treat Acanthamoeba infection.


Assuntos
Acanthamoeba/metabolismo , Aminopeptidases/imunologia , Aminopeptidases/metabolismo , Complemento C3/metabolismo , Proteínas de Protozoários/imunologia , Proteínas de Protozoários/metabolismo , Acanthamoeba/isolamento & purificação , Amebíase/parasitologia , Aminopeptidases/genética , Sistemas CRISPR-Cas , Humanos , Lagos/parasitologia , Proteínas de Protozoários/genética , Solo/parasitologia
11.
PLoS Negl Trop Dis ; 13(5): e0007352, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31095564

RESUMO

BACKGROUND: Acanthamoeba castellanii, which causes keratitis and blindness in under-resourced countries, is an emerging pathogen worldwide, because of its association with contact lens use. The wall makes cysts resistant to sterilizing reagents in lens solutions and to antibiotics applied to the eye. METHODOLOGY/PRINCIPAL FINDINGS: Transmission electron microscopy and structured illumination microscopy (SIM) showed purified cyst walls of A. castellanii retained an outer ectocyst layer, an inner endocyst layer, and conical ostioles that connect them. Mass spectrometry showed candidate cyst wall proteins were dominated by three families of lectins (named here Jonah, Luke, and Leo), which bound well to cellulose and less well to chitin. An abundant Jonah lectin, which has one choice-of-anchor A (CAA) domain, was made early during encystation and localized to the ectocyst layer of cyst walls. An abundant Luke lectin, which has two carbohydrate-binding modules (CBM49), outlined small, flat ostioles in a single-layered primordial wall and localized to the endocyst layer and ostioles of mature walls. An abundant Leo lectin, which has two unique domains with eight Cys residues each (8-Cys), localized to the endocyst layer and ostioles. The Jonah lectin and glycopolymers, to which it binds, were accessible in the ectocyst layer. In contrast, Luke and Leo lectins and the glycopolymers, to which they bind, were mostly inaccessible in the endocyst layer and ostioles. CONCLUSIONS/SIGNIFICANCE: The most abundant A. castellanii cyst wall proteins are three sets of lectins, which have carbohydrate-binding modules that are conserved (CBM49s of Luke), newly characterized (CAA of Jonah), or unique to Acanthamoebae (8-Cys of Leo). Cyst wall formation is a tightly choreographed event, in which lectins and glycopolymers combine to form a mature wall with a protected endocyst layer. Because of its accessibility in the ectocyst layer, an abundant Jonah lectin is an excellent diagnostic target.


Assuntos
Acanthamoeba castellanii/crescimento & desenvolvimento , Acanthamoeba castellanii/metabolismo , Amebíase/parasitologia , Celulose/metabolismo , Lectinas/metabolismo , Proteínas de Protozoários/metabolismo , Acanthamoeba castellanii/química , Acanthamoeba castellanii/genética , Sequência de Aminoácidos , Humanos , Ceratite/parasitologia , Lectinas/química , Lectinas/genética , Estágios do Ciclo de Vida , Ligação Proteica , Transporte Proteico , Proteínas de Protozoários/química , Proteínas de Protozoários/genética , Alinhamento de Sequência
12.
Parasitol Res ; 118(6): 1999-2004, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30972570

RESUMO

In the present article, we report on the identification of Vermamoeba (Hartmannella) vermiformis as the etiological agent of a tissue infection close to the eye of a female patient. Laboratory examination revealed no involvement of any pathogenic bacteria or fungi in the tissue infection. V. vermiformis was identified by cultivation and morphology of trophozoites and cysts as well as phylogenetic analysis of nuclear 18S rDNA. The lesion improved in the course of 4 weeks by application of zinc paste.


Assuntos
Amebíase/diagnóstico , Amebíase/patologia , Hartmannella/patogenicidade , Úlcera/parasitologia , Adulto , Amebíase/parasitologia , Animais , DNA de Protozoário/genética , DNA Ribossômico/genética , Feminino , Hartmannella/classificação , Hartmannella/genética , Humanos , Filogenia , Trofozoítos/classificação , Trofozoítos/crescimento & desenvolvimento , Úlcera/patologia
13.
Mini Rev Med Chem ; 19(12): 980-987, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30868950

RESUMO

Pathogenic free-living amoeba are known to cause a devastating infection of the central nervous system and are often referred to as "brain-eating amoebae". The mortality rate of more than 90% and free-living nature of these amoebae is a cause for concern. It is distressing that the mortality rate has remained the same over the past few decades, highlighting the lack of interest by the pharmaceutical industry. With the threat of global warming and increased outdoor activities of public, there is a need for renewed interest in identifying potential anti-amoebic compounds for successful prognosis. Here, we discuss the available chemotherapeutic options and opportunities for potential strategies in the treatment and diagnosis of these life-threatening infections.


Assuntos
Amebíase/tratamento farmacológico , Amebíase/parasitologia , Amoeba/efeitos dos fármacos , Encéfalo/parasitologia , Doenças do Sistema Nervoso Central/tratamento farmacológico , Doenças do Sistema Nervoso Central/parasitologia , Naegleria fowleri/efeitos dos fármacos , Naegleria fowleri/parasitologia , Amebíase/diagnóstico , Doenças do Sistema Nervoso Central/diagnóstico , Humanos
15.
Exp Parasitol ; 197: 29-35, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30648558

RESUMO

Free-living amoebae of the genus Acanthamoeba are the etiological agents of cutaneous lesions, granulomatous amoebic encephalitis (GAE) and amoebic keratitis (AK), which are chronic infections with poor prognosis if not diagnosed promptly. Currently, there is no optimal therapeutic scheme to eradicate the pathologies these protozoa cause. In this study we report the morphological and molecular identification of three species of the genus Acanthamoeba, belonging to T4 group; A. polyphaga isolated from the corneal ulcer of a patient sample of AK case; A. castellanii isolated from the contact lens of an AK patient and A. palestinensis obtained from a soil sample. The in vitro activity of chlorhexidine, itraconazole and voriconazole drugs against trophic stage was also evaluated through a colorimetric assay based on the oxidation-reduction of alamar blue. The strains in the study were sensitive to the evaluated drugs; although when determining the 50% inhibitory concentration (IC50) statistically significant differences were observed. A. castellanii showed to be highly sensitive to voriconazole (0.66 ±â€¯0.13 µM) but the least sensitive to chlorhexidine and itraconazole (8.61 ±â€¯1.63 and 20.14 ±â€¯4.93 µM, respectively), A. palestinensis showed the highest sensitivity to itraconazole (0.502 ±â€¯0.11 µM) and A. polyphaga expressed moderate sensitivity to chlorhexidine and itraconazole and lower sensitivity to voriconazole (10.10 ±â€¯2.21 µM). These results showed that species of the genus Acanthamoeba express different sensitivity to the tested drugs, which could explain the problems surrounding the establishment of a treatment of choice in the infections caused by these amoebae. We consider that although chlorhexidine and itraconazole show good activity on these amoebae and have been used in cases of AK in Mexico with acceptable results, voriconazole should be considered as the first therapeutic option of future Acanthamoeba infections that will be diagnosed in our country.


Assuntos
Acanthamoeba/efeitos dos fármacos , Amebíase/parasitologia , Anti-Infecciosos/farmacologia , Clorexidina/farmacologia , Itraconazol/farmacologia , Voriconazol/farmacologia , Acanthamoeba/classificação , Acanthamoeba/genética , Ceratite por Acanthamoeba/parasitologia , Amebíase/tratamento farmacológico , Lentes de Contato/parasitologia , Úlcera da Córnea/parasitologia , DNA de Protozoário/isolamento & purificação , Genótipo , Humanos , Concentração Inibidora 50 , México , Solo/parasitologia
16.
Eur J Protistol ; 67: 27-45, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30447480

RESUMO

Neoparamoeba perurans is the aetiological agent of amoebic gill disease (AGD) in salmonids, however multiple other amoeba species colonise the gills and their role in AGD is unknown. Taxonomic assessments of these accompanying amoebae on AGD-affected salmon have previously been based on gross morphology alone. The aim of the present study was to document the diversity of amoebae colonising the gills of AGD-affected farmed Atlantic salmon using a combination of morphological and sequence-based taxonomic methods. Amoebae were characterised morphologically via light microscopy and transmission electron microscopy, and by phylogenetic analyses based on the 18S rRNA gene and cytochrome oxidase subunit I (COI) gene. In addition to N. perurans, 11 other amoebozoans were isolated from the gills, and were classified within the genera Neoparamoeba, Paramoeba, Vexillifera, Pseudoparamoeba, Vannella and Nolandella. In some cases, such as Paramoeba eilhardi, this is the first time this species has been isolated from the gills of teleost fish. Furthermore, sequencing of both the 18S rRNA and COI gene revealed significant genetic variation within genera. We highlight that there is a far greater diversity of amoebae colonising AGD-affected gills than previously established.


Assuntos
Amebíase/veterinária , Biodiversidade , Doenças dos Peixes/parasitologia , Brânquias/parasitologia , Salmo salar/parasitologia , Amebíase/parasitologia , Amebozoários/classificação , Amebozoários/genética , Amebozoários/ultraestrutura , Animais , Complexo IV da Cadeia de Transporte de Elétrons/genética , Microscopia , Microscopia Eletrônica de Transmissão , Filogenia , RNA Ribossômico 18S/genética
17.
Curr Drug Targets ; 20(1): 60-69, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-29697029

RESUMO

Despite advances in drug discovery and modifications in the chemotherapeutic regimens, human infections caused by free-living amoebae (FLA) have high mortality rates (~95%). The FLA that cause fatal human cerebral infections include Naegleria fowleri, Balamuthia mandrillaris and Acanthamoeba spp. Novel drug-target discovery remains the only viable option to tackle these central nervous system (CNS) infection in order to lower the mortality rates caused by the FLA. Of these FLA, N. fowleri causes primary amoebic meningoencephalitis (PAM), while the A. castellanii and B. Mandrillaris are known to cause granulomatous amoebic encephalitis (GAE). The infections caused by the FLA have been treated with drugs like Rifampin, Fluconazole, Amphotericin-B and Miltefosine. Miltefosine is an anti-leishmanial agent and an experimental anti-cancer drug. With only rare incidences of success, these drugs have remained unsuccessful to lower the mortality rates of the cerebral infection caused by FLA. Recently, with the help of bioinformatic computational tools and the discovered genomic data of the FLA, discovery of newer drug targets has become possible. These cellular targets are proteins that are either unique to the FLA or shared between the humans and these unicellular eukaryotes. The latter group of proteins has shown to be targets of some FDA approved drugs prescribed in non-infectious diseases. This review out-lines the bioinformatics methodologies that can be used in the discovery of such novel drug-targets, their chronicle by in-vitro assays done in the past and the translational value of such target discoveries in human diseases caused by FLA.


Assuntos
Amebíase/tratamento farmacológico , Amoeba/efeitos dos fármacos , Infecções Protozoárias do Sistema Nervoso Central/tratamento farmacológico , Descoberta de Drogas/métodos , Encefalite Infecciosa/tratamento farmacológico , Proteínas de Protozoários/antagonistas & inibidores , Amebíase/parasitologia , Amoeba/metabolismo , Animais , Infecções Protozoárias do Sistema Nervoso Central/parasitologia , Biologia Computacional , Modelos Animais de Doenças , Drogas em Investigação/farmacologia , Drogas em Investigação/uso terapêutico , Humanos , Encefalite Infecciosa/parasitologia , Terapia de Alvo Molecular/métodos , Proteínas de Protozoários/metabolismo
18.
PLoS Negl Trop Dis ; 12(12): e0006979, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30557322

RESUMO

BACKGROUND: In previous studies, we suggested that Acanthamoeba is a new aero-allergen and that patients who showed positive results for the skin-prick test response to Acanthamoeba cross-reacted with several pollen allergens. Additionally, patients with common antibodies reacted to the 13-15 kDa Acanthamoeba unknown allergen. OBJECTIVE: We examined whether profilin of Acanthamoeba is a human airway allergic agent because of its molecular weight. METHODS: We expressed recombinant Ac-PF (rAc-PF) protein using an Escherichia coli expression system and evaluated whether Ac-PF is an airway allergic agent using an allergic airway inflammation animal model. RESULTS: Airway hyperresponsiveness was increased in rAc-PF-inoculated mice. The number of eosinophils and levels of Th2 cytokines, interleukin (IL)-4, IL-5, and IL-13 were increased in the bronchial alveolar lavage fluid of rAc-PF-treated mice. The lungs of the rAc-PF-treated mice group showed enhanced mucin production and metaplasia of lung epithelial cells and goblet cells. CONCLUSION: In this study, we demonstrated that rAc-PF may be an allergen in Acanthamoeba, but further studies needed to identify the mechanisms of allergenic reactions induced by Ac-PF.


Assuntos
Acanthamoeba/imunologia , Amebíase/imunologia , Profilinas/imunologia , Hipersensibilidade Respiratória/imunologia , Acanthamoeba/genética , Amebíase/genética , Amebíase/parasitologia , Animais , Modelos Animais de Doenças , Feminino , Humanos , Interleucina-13/genética , Interleucina-13/imunologia , Interleucina-4/genética , Interleucina-4/imunologia , Pulmão/imunologia , Pulmão/parasitologia , Camundongos , Camundongos Endogâmicos C57BL , Profilinas/genética , Ratos , Ratos Wistar , Hipersensibilidade Respiratória/genética , Hipersensibilidade Respiratória/parasitologia
19.
mBio ; 9(5)2018 10 30.
Artigo em Inglês | MEDLINE | ID: mdl-30377287

RESUMO

Balamuthia mandrillaris is a pathogenic free-living amoeba that causes a rare but almost always fatal infection of the central nervous system called granulomatous amoebic encephalitis (GAE). Two distinct forms of B. mandrillaris-a proliferative trophozoite form and a nonproliferative cyst form, which is highly resistant to harsh physical and chemical conditions-have been isolated from environmental samples worldwide and are both observed in infected tissue. Patients suffering from GAE are typically treated with aggressive and prolonged multidrug regimens that often include the antimicrobial agents miltefosine and pentamidine isethionate. However, survival rates remain low, and studies evaluating the susceptibility of B. mandrillaris to these compounds and other potential therapeutics are limited. To address the need for more-effective treatments, we screened 2,177 clinically approved compounds for in vitro activity against B. mandrillaris The quinoline antibiotic nitroxoline (8-hydroxy-5-nitroquinoline), which has safely been used in humans to treat urinary tract infections, was identified as a lead compound. We show that nitroxoline inhibits both trophozoites and cysts at low micromolar concentrations, which are within a pharmacologically relevant range. We compared the in vitro efficacy of nitroxoline to that of drugs currently used in the standard of care for GAE and found that nitroxoline is the most potent and selective inhibitor of B. mandrillaris tested. Furthermore, we demonstrate that nitroxoline prevents B. mandrillaris-mediated destruction of host cells in cultured fibroblast and primary brain explant models also at pharmacologically relevant concentrations. Taken together, our findings indicate that nitroxoline is a promising candidate for repurposing as a novel treatment of B. mandrillaris infections.IMPORTANCE Balamuthia mandrillaris is responsible for hundreds of reported cases of amoebic encephalitis, the majority of which have been fatal. Despite being an exceptionally deadly pathogen, B. mandrillaris is understudied, leaving many open questions regarding epidemiology, diagnosis, and treatment. Due to the lack of effective drugs to fight B. mandrillaris infections, mortality rates remain high even for patients receiving intensive care. This report addresses the need for new treatment options through a drug repurposing screen to identify novel B. mandrillaris inhibitors. The most promising candidate identified was the quinoline antibiotic nitroxoline, which has a long history of safe use in humans. We show that nitroxoline kills B. mandrillaris at pharmacologically relevant concentrations and exhibits greater potency and selectivity than drugs commonly used in the current standard of care. The findings that we present demonstrate the potential of nitroxoline to be an important new tool in the treatment of life-threatening B. mandrillaris infections.


Assuntos
Amebicidas/farmacologia , Balamuthia mandrillaris/efeitos dos fármacos , Nitroquinolinas/farmacologia , Amebíase/tratamento farmacológico , Amebíase/parasitologia , Amebíase/patologia , Balamuthia mandrillaris/crescimento & desenvolvimento , Encéfalo/parasitologia , Encéfalo/patologia , Linhagem Celular , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Fibroblastos/parasitologia , Fibroblastos/patologia , Humanos , Modelos Biológicos , Testes de Sensibilidade Parasitária
20.
PLoS Pathog ; 14(10): e1007295, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30308066

RESUMO

Amebiasis, a global intestinal parasitic disease, is due to Entamoeba histolytica. This parasite, which feeds on bacteria in the large intestine of its human host, can trigger a strong inflammatory response upon invasion of the colonic mucosa. Whereas information about the mechanisms which are used by the parasite to cope with oxidative and nitrosative stresses during infection is available, knowledge about the contribution of bacteria to these mechanisms is lacking. In a recent study, we demonstrated that enteropathogenic Escherichia coli O55 protects E. histolytica against oxidative stress. Resin-assisted capture (RAC) of oxidized (OX) proteins coupled to mass spectrometry (OX-RAC) was used to investigate the oxidation status of cysteine residues in proteins present in E. histolytica trophozoites incubated with live or heat-killed E. coli O55 and then exposed to H2O2-mediated oxidative stress. We found that the redox proteome of E. histolytica exposed to heat-killed E. coli O55 is enriched with proteins involved in redox homeostasis, lipid metabolism, small molecule metabolism, carbohydrate derivative metabolism, and organonitrogen compound biosynthesis. In contrast, we found that proteins associated with redox homeostasis were the only OX-proteins that were enriched in E. histolytica trophozoites which were incubated with live E. coli O55. These data indicate that E. coli has a profound impact on the redox proteome of E. histolytica. Unexpectedly, some E. coli proteins were also co-identified with E. histolytica proteins by OX-RAC. We demonstrated that one of these proteins, E. coli malate dehydrogenase (EcMDH) and its product, oxaloacetate, are key elements of E. coli-mediated resistance of E. histolytica to oxidative stress and that oxaloacetate helps the parasite survive in the large intestine. We also provide evidence that the protective effect of oxaloacetate against oxidative stress extends to Caenorhabditis elegans.


Assuntos
Entamoeba histolytica/efeitos dos fármacos , Entamebíase/tratamento farmacológico , Escherichia coli/fisiologia , Ácido Oxaloacético/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Proteínas de Protozoários/metabolismo , Amebíase/tratamento farmacológico , Amebíase/metabolismo , Amebíase/parasitologia , Animais , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/crescimento & desenvolvimento , Caenorhabditis elegans/parasitologia , Células Cultivadas , Entamebíase/metabolismo , Entamebíase/parasitologia , Células HeLa , Humanos , Intestino Grosso/efeitos dos fármacos , Intestino Grosso/metabolismo , Intestino Grosso/parasitologia , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/parasitologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA
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