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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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Percentage of T. gondii infected SkMC after 24 h of interaction. (A) Percentage of myoblasts (61%) and myotubes (38%) infected with T. gondii after 24 h of interaction. Student's T-test (*) p ≤ 0.05. (B) Details of SkMC cultures profile observed by fluorescence microscopy with phaloidin-TRITC labeling showing actin filaments in red; nuclei of the cells and the parasites labeled with DAPI, in blue. Infected cultures present myoblasts containing several parasites (thick arrow) and young myotubes with 2 nuclei without parasites (thin arrows). Bars, 20 μm
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Figure 1: Percentage of T. gondii infected SkMC after 24 h of interaction. (A) Percentage of myoblasts (61%) and myotubes (38%) infected with T. gondii after 24 h of interaction. Student's T-test (*) p ≤ 0.05. (B) Details of SkMC cultures profile observed by fluorescence microscopy with phaloidin-TRITC labeling showing actin filaments in red; nuclei of the cells and the parasites labeled with DAPI, in blue. Infected cultures present myoblasts containing several parasites (thick arrow) and young myotubes with 2 nuclei without parasites (thin arrows). Bars, 20 μm

Mentions: Only the number of infected myoblasts and myotubes was evaluated, independently of the number of parasites internalized. The total number of infected cells (harboring at least one internalized parasite), after 24 h of SkMC - parasite interaction, represented 61% of myoblasts and 38% of myotubes. These data indicate that myotubes were 1.6-fold less infected than myoblasts (Figure 1A). Figure 1B shows young and mature uninfected myotubes surrounded by several heavily infected myoblasts after 48 h of interaction.


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)

Percentage of T. gondii infected SkMC after 24 h of interaction. (A) Percentage of myoblasts (61%) and myotubes (38%) infected with T. gondii after 24 h of interaction. Student's T-test (*) p ≤ 0.05. (B) Details of SkMC cultures profile observed by fluorescence microscopy with phaloidin-TRITC labeling showing actin filaments in red; nuclei of the cells and the parasites labeled with DAPI, in blue. Infected cultures present myoblasts containing several parasites (thick arrow) and young myotubes with 2 nuclei without parasites (thin arrows). Bars, 20 μm
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 1: Percentage of T. gondii infected SkMC after 24 h of interaction. (A) Percentage of myoblasts (61%) and myotubes (38%) infected with T. gondii after 24 h of interaction. Student's T-test (*) p ≤ 0.05. (B) Details of SkMC cultures profile observed by fluorescence microscopy with phaloidin-TRITC labeling showing actin filaments in red; nuclei of the cells and the parasites labeled with DAPI, in blue. Infected cultures present myoblasts containing several parasites (thick arrow) and young myotubes with 2 nuclei without parasites (thin arrows). Bars, 20 μm
Mentions: Only the number of infected myoblasts and myotubes was evaluated, independently of the number of parasites internalized. The total number of infected cells (harboring at least one internalized parasite), after 24 h of SkMC - parasite interaction, represented 61% of myoblasts and 38% of myotubes. These data indicate that myotubes were 1.6-fold less infected than myoblasts (Figure 1A). Figure 1B shows young and mature uninfected myotubes surrounded by several heavily infected myoblasts after 48 h of interaction.

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