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1.
Parasit Vectors ; 7: 47, 2014 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-24457118

RESUMO

BACKGROUND: The interest in the mechanisms involved in Toxoplasma gondii lipid acquisition has steadily increased during the past few decades, but it remains not completely understood. Here, we investigated the biogenesis and the fate of lipid droplets (LD) of skeletal muscle cells (SkMC) during their interaction with T. gondii by confocal and electron microscopy. We also evaluated whether infected SkMC modulates the production of prostaglandin E2 (PGE2), cytokines interleukin-12 (IL-12) and interferon-gamma (INF-g), and also the cyclooxygenase-2 (COX-2) gene induction. METHODS: Primary culture of skeletal muscle cells were infected with tachyzoites of T. gondii and analysed by confocal microscopy for observation of LD. Ultrastructural cytochemistry was also used for lipid and sarcoplasmatic reticulum (SR) detection. Dosage of cytokines (IL-12 and INF-g) by ELISA technique and enzyme-linked immunoassay (EIA) for PGE2 measurement were employed. The COX-2 gene expression analysis was performed by real time reverse transcriptase polymerase chain reaction (qRT-PCR). RESULTS: We demonstrated that T. gondii infection of SkMC leads to increase in LD number and area in a time course dependent manner. Moreover, the ultrastructural analysis demonstrated that SR and LD are in direct contact with parasitophorous vacuole membrane (PVM), within the vacuolar matrix, around it and interacting directly with the membrane of parasite, indicating that LD are recruited and deliver their content inside the parasitophorous vacuole (PV) in T. gondii-infected SkMC. We also observed a positive modulation of the production of IL-12 and IFN-g, increase of COX-2 mRNA levels in the first hour of T. gondii-SkMC interaction and an increase of prostaglandin E2 (PGE2) synthesis from 6 h up to 48 h of infection. CONCLUSIONS: Taken together, the close association between SR and LD with PV could represent a source of lipids as well as other nutrients for the parasite survival, and together with the increased levels of IL-12, INF-g and inflammatory indicators PGE2 and COX-2 might contribute to the establishment and maintenance of chronic phase of the T. gondii infection in muscle cell.


Assuntos
Dinoprostona/biossíntese , Interferon gama/biossíntese , Interleucina-12/biossíntese , Lipídeos/biossíntese , Fibras Musculares Esqueléticas/metabolismo , Toxoplasma/metabolismo , Animais , Citocinas/biossíntese , Eicosanoides/metabolismo , Camundongos , Fibras Musculares Esqueléticas/ultraestrutura , Cultura Primária de Células , Retículo Sarcoplasmático/metabolismo
2.
BMC Microbiol ; 11: 110, 2011 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-21592384

RESUMO

BACKGROUND: Toxoplasma gondii belongs to a large and diverse group of obligate intracellular parasitic protozoa. Primary culture of mice skeletal muscle cells (SkMC) was employed as a model for experimental toxoplasmosis studies. The myogenesis of SkMC was reproduced in vitro and the ability of T. gondii tachyzoite forms to infect myoblasts and myotubes and its influence on SkMC myogenesis were analyzed. RESULTS: In this study we show that, after 24 h of interaction, myoblasts (61%) were more infected with T. gondii than myotubes (38%) and inhibition of myogenesis was about 75%. The role of adhesion molecules such as cadherin in this event was investigated. First, we demonstrate that cadherin localization was restricted to the contact areas between myocytes/myocytes and myocytes/myotubes during the myogenesis process. Immunofluorescence and immunoblotting analysis of parasite-host cell interaction showed a 54% reduction in cadherin expression at 24 h of infection. Concomitantly, a reduction in M-cadherin mRNA levels was observed after 3 and 24 h of T. gondii-host cell interaction. CONCLUSIONS: These data suggest that T. gondii is able to down regulate M-cadherin expression, leading to molecular modifications in the host cell surface that interfere with membrane fusion and consequently affect the myogenesis process.


Assuntos
Caderinas/antagonistas & inibidores , Desenvolvimento Muscular , Músculo Esquelético/patologia , Músculo Esquelético/parasitologia , Toxoplasma/patogenicidade , Animais , Células Cultivadas , Perfilação da Expressão Gênica , Interações Hospedeiro-Parasita , Camundongos , Fibras Musculares Esqueléticas/parasitologia , Fibras Musculares Esqueléticas/patologia , Mioblastos/parasitologia , Mioblastos/fisiologia
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