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Toxoplasma gondii down modulates cadherin expression in skeletal muscle cells inhibiting myogenesis.

Gomes AF, Guimarães EV, Carvalho L, Correa JR, Mendonça-Lima L, Barbosa HS - BMC Microbiol. (2011)

Bottom Line: 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.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratório de Biologia Estrutural, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, (Av, Brasil 4365), Rio de Janeiro (21040-361), Brazil.

ABSTRACT

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.

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Cadherin profile in differentiated cultures after 24 h of T. gondii interaction. (A and inset) Mature (arrowhead) and young myotubes in fusion process with myoblasts (arrows) can be observed by phase contrast microscopy. (B and inset) By fluorescence microscopy, cadherin (in green) appears distributed throughout the myotubes, being more concentrated at the cell membrane during adhesion, while mature myotubes alone show more intense labeling at the extremities. (C) Interferential microscopy shows the adhesion of uninfected myoblasts (arrowhead) with a mature infected myotube (thick arrows). (D) Confocal microscopy analysis shows that infected myoblasts do not reveal cadherin labeling and more infected myotubes present weaker cadherin labeling (arrow). Observe that despite the weak labeling, in infected myotubes cadherin molecules appear to migrate to the point of contact with uninfected myoblasts (arrowhead). (E) Merge. Bars, 20 μm
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Figure 5: Cadherin profile in differentiated cultures after 24 h of T. gondii interaction. (A and inset) Mature (arrowhead) and young myotubes in fusion process with myoblasts (arrows) can be observed by phase contrast microscopy. (B and inset) By fluorescence microscopy, cadherin (in green) appears distributed throughout the myotubes, being more concentrated at the cell membrane during adhesion, while mature myotubes alone show more intense labeling at the extremities. (C) Interferential microscopy shows the adhesion of uninfected myoblasts (arrowhead) with a mature infected myotube (thick arrows). (D) Confocal microscopy analysis shows that infected myoblasts do not reveal cadherin labeling and more infected myotubes present weaker cadherin labeling (arrow). Observe that despite the weak labeling, in infected myotubes cadherin molecules appear to migrate to the point of contact with uninfected myoblasts (arrowhead). (E) Merge. Bars, 20 μm

Mentions: During myogenesis in vitro, myoblasts interact with the surface of myotubes. The dynamics of this interaction induces the translocation of cadherin from the extremities of myotubes to the point of cell-cell contact (Figure 5A, B and inset). Labeling for cadherin was observed at the end of infected myotubes, especially at points of contact with uninfected myoblasts, suggesting migration of cadherin to the sites of possible membrane fusion (Figure 5C-E).


Toxoplasma gondii down modulates cadherin expression in skeletal muscle cells inhibiting myogenesis.

Gomes AF, Guimarães EV, Carvalho L, Correa JR, Mendonça-Lima L, Barbosa HS - BMC Microbiol. (2011)

Cadherin profile in differentiated cultures after 24 h of T. gondii interaction. (A and inset) Mature (arrowhead) and young myotubes in fusion process with myoblasts (arrows) can be observed by phase contrast microscopy. (B and inset) By fluorescence microscopy, cadherin (in green) appears distributed throughout the myotubes, being more concentrated at the cell membrane during adhesion, while mature myotubes alone show more intense labeling at the extremities. (C) Interferential microscopy shows the adhesion of uninfected myoblasts (arrowhead) with a mature infected myotube (thick arrows). (D) Confocal microscopy analysis shows that infected myoblasts do not reveal cadherin labeling and more infected myotubes present weaker cadherin labeling (arrow). Observe that despite the weak labeling, in infected myotubes cadherin molecules appear to migrate to the point of contact with uninfected myoblasts (arrowhead). (E) Merge. Bars, 20 μm
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3116462&req=5

Figure 5: Cadherin profile in differentiated cultures after 24 h of T. gondii interaction. (A and inset) Mature (arrowhead) and young myotubes in fusion process with myoblasts (arrows) can be observed by phase contrast microscopy. (B and inset) By fluorescence microscopy, cadherin (in green) appears distributed throughout the myotubes, being more concentrated at the cell membrane during adhesion, while mature myotubes alone show more intense labeling at the extremities. (C) Interferential microscopy shows the adhesion of uninfected myoblasts (arrowhead) with a mature infected myotube (thick arrows). (D) Confocal microscopy analysis shows that infected myoblasts do not reveal cadherin labeling and more infected myotubes present weaker cadherin labeling (arrow). Observe that despite the weak labeling, in infected myotubes cadherin molecules appear to migrate to the point of contact with uninfected myoblasts (arrowhead). (E) Merge. Bars, 20 μm
Mentions: During myogenesis in vitro, myoblasts interact with the surface of myotubes. The dynamics of this interaction induces the translocation of cadherin from the extremities of myotubes to the point of cell-cell contact (Figure 5A, B and inset). Labeling for cadherin was observed at the end of infected myotubes, especially at points of contact with uninfected myoblasts, suggesting migration of cadherin to the sites of possible membrane fusion (Figure 5C-E).

Bottom Line: 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.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratório de Biologia Estrutural, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, (Av, Brasil 4365), Rio de Janeiro (21040-361), Brazil.

ABSTRACT

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.

Show MeSH
Related in: MedlinePlus