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Pyrimidinergic Receptor Activation Controls Toxoplasma gondii Infection in Macrophages.

Moreira-Souza AC, Marinho Y, Correa G, Santoro GF, Coutinho CM, Vommaro RC, Coutinho-Silva R - PLoS ONE (2015)

Bottom Line: Treatment with these nucleotides reduced parasitic load by 90%, but did not increase the levels of the inflammatory mediators NO and ROS, nor did it modulate host cell death by apoptosis or necrosis.In subsequent infections, prematurely egressed parasites had reduced infectivity, and could neither replicate nor inhibit the fusion of lysosomes to the parasitophorous vacuole.The use of selective agonists and antagonists of the receptor subtypes P2Y2 and P2Y4 and P2Y6 showed that premature parasite egress may be mediated by the activation of these receptor subtypes.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Imunofisiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-902, Brazil; Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-902, Brazil; Instituto Nacional de Ciência e Tecnologia para Pesquisa Translacional em Saúde e Ambiente na Região Amazônica (INPeTAm/UFRJ), Rio de Janeiro, RJ, 21941-902, Brazil.

ABSTRACT
Infection by the protozoan parasite Toxoplasma gondii is highly prevalent worldwide and may have serious clinical manifestations in immunocompromised patients. T. gondii is an obligate intracellular parasite that infects almost any cell type in mammalian hosts, including immune cells. The immune cells express purinergic P2 receptors in their membrane--subdivided into P2Y and P2X subfamilies--whose activation is important for infection control. Here, we examined the effect of treatment with UTP and UDP in mouse peritoneal macrophages infected with T. gondii tachyzoites. Treatment with these nucleotides reduced parasitic load by 90%, but did not increase the levels of the inflammatory mediators NO and ROS, nor did it modulate host cell death by apoptosis or necrosis. On the other hand, UTP and UDP treatments induced early egress of tachyzoites from infected macrophages, in a Ca2+-dependent manner, as shown by scanning electron microscopy analysis, and videomicroscopy. In subsequent infections, prematurely egressed parasites had reduced infectivity, and could neither replicate nor inhibit the fusion of lysosomes to the parasitophorous vacuole. The use of selective agonists and antagonists of the receptor subtypes P2Y2 and P2Y4 and P2Y6 showed that premature parasite egress may be mediated by the activation of these receptor subtypes. Our results suggest that the activity of P2Y host cell receptors controls T. gondii infection in macrophages, highlighting the importance of pyrimidinergic signaling for innate immune system response against infection. Finally the P2Y receptors should be considered as new target for the development of drugs against T. gondii infection.

No MeSH data available.


Related in: MedlinePlus

The activation of different P2Y receptor subtypes reduce T. gondii infection in peritoneal macrophages.Mouse peritoneal macrophages were infected with T. gondii tachyzoites at a ratio of 5:1 for 2 h and then treated with specific P2Y receptor agonists and antagonists for 30 min, prior to infection index determination. (A) Treatment 2 Thio-UTP at concentrations of 0.05 or 0.1 μM (to activate P2Y4) and 0.5 or 1 μM of 2 Thio-UTP (to activate P2Y2) led to similar reductions in the infection index relative to untreated controls. (B) The infection index was also reduced after treatment with MRS 2693, a specific P2Y6 agonist, and MRS 2693 effect was totally blocked by pre-treatment with the specific P2Y6 antagonist MRS 2578. The 20, 50, 100 represent on the x-axis concentration of the agonist/antagonist. * statistically significant relative to untreated. # statistically significant relative to reduction of infection index. Data represent mean and SEM of three independent experiments. * p < 0,05; **,## p < 0.001; ***, ### p < 0.0001.
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pone.0133502.g009: The activation of different P2Y receptor subtypes reduce T. gondii infection in peritoneal macrophages.Mouse peritoneal macrophages were infected with T. gondii tachyzoites at a ratio of 5:1 for 2 h and then treated with specific P2Y receptor agonists and antagonists for 30 min, prior to infection index determination. (A) Treatment 2 Thio-UTP at concentrations of 0.05 or 0.1 μM (to activate P2Y4) and 0.5 or 1 μM of 2 Thio-UTP (to activate P2Y2) led to similar reductions in the infection index relative to untreated controls. (B) The infection index was also reduced after treatment with MRS 2693, a specific P2Y6 agonist, and MRS 2693 effect was totally blocked by pre-treatment with the specific P2Y6 antagonist MRS 2578. The 20, 50, 100 represent on the x-axis concentration of the agonist/antagonist. * statistically significant relative to untreated. # statistically significant relative to reduction of infection index. Data represent mean and SEM of three independent experiments. * p < 0,05; **,## p < 0.001; ***, ### p < 0.0001.

Mentions: The agonist 2Thio-UTP activates P2Y2 and P2Y4 at different concentrations [27]. Similar reductions in the infection index (82%) that were observed in UTP treatment were observed in infected macrophages treated with 2Thio-UTP at the concentrations of 0.05 and 0.1 μM, which trigger P2Y2 activation only, and at the concentrations of 0.5 and 1 μM, which activate both P2Y2 and P2Y4 (Fig 9A).


Pyrimidinergic Receptor Activation Controls Toxoplasma gondii Infection in Macrophages.

Moreira-Souza AC, Marinho Y, Correa G, Santoro GF, Coutinho CM, Vommaro RC, Coutinho-Silva R - PLoS ONE (2015)

The activation of different P2Y receptor subtypes reduce T. gondii infection in peritoneal macrophages.Mouse peritoneal macrophages were infected with T. gondii tachyzoites at a ratio of 5:1 for 2 h and then treated with specific P2Y receptor agonists and antagonists for 30 min, prior to infection index determination. (A) Treatment 2 Thio-UTP at concentrations of 0.05 or 0.1 μM (to activate P2Y4) and 0.5 or 1 μM of 2 Thio-UTP (to activate P2Y2) led to similar reductions in the infection index relative to untreated controls. (B) The infection index was also reduced after treatment with MRS 2693, a specific P2Y6 agonist, and MRS 2693 effect was totally blocked by pre-treatment with the specific P2Y6 antagonist MRS 2578. The 20, 50, 100 represent on the x-axis concentration of the agonist/antagonist. * statistically significant relative to untreated. # statistically significant relative to reduction of infection index. Data represent mean and SEM of three independent experiments. * p < 0,05; **,## p < 0.001; ***, ### p < 0.0001.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4507979&req=5

pone.0133502.g009: The activation of different P2Y receptor subtypes reduce T. gondii infection in peritoneal macrophages.Mouse peritoneal macrophages were infected with T. gondii tachyzoites at a ratio of 5:1 for 2 h and then treated with specific P2Y receptor agonists and antagonists for 30 min, prior to infection index determination. (A) Treatment 2 Thio-UTP at concentrations of 0.05 or 0.1 μM (to activate P2Y4) and 0.5 or 1 μM of 2 Thio-UTP (to activate P2Y2) led to similar reductions in the infection index relative to untreated controls. (B) The infection index was also reduced after treatment with MRS 2693, a specific P2Y6 agonist, and MRS 2693 effect was totally blocked by pre-treatment with the specific P2Y6 antagonist MRS 2578. The 20, 50, 100 represent on the x-axis concentration of the agonist/antagonist. * statistically significant relative to untreated. # statistically significant relative to reduction of infection index. Data represent mean and SEM of three independent experiments. * p < 0,05; **,## p < 0.001; ***, ### p < 0.0001.
Mentions: The agonist 2Thio-UTP activates P2Y2 and P2Y4 at different concentrations [27]. Similar reductions in the infection index (82%) that were observed in UTP treatment were observed in infected macrophages treated with 2Thio-UTP at the concentrations of 0.05 and 0.1 μM, which trigger P2Y2 activation only, and at the concentrations of 0.5 and 1 μM, which activate both P2Y2 and P2Y4 (Fig 9A).

Bottom Line: Treatment with these nucleotides reduced parasitic load by 90%, but did not increase the levels of the inflammatory mediators NO and ROS, nor did it modulate host cell death by apoptosis or necrosis.In subsequent infections, prematurely egressed parasites had reduced infectivity, and could neither replicate nor inhibit the fusion of lysosomes to the parasitophorous vacuole.The use of selective agonists and antagonists of the receptor subtypes P2Y2 and P2Y4 and P2Y6 showed that premature parasite egress may be mediated by the activation of these receptor subtypes.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Imunofisiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-902, Brazil; Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-902, Brazil; Instituto Nacional de Ciência e Tecnologia para Pesquisa Translacional em Saúde e Ambiente na Região Amazônica (INPeTAm/UFRJ), Rio de Janeiro, RJ, 21941-902, Brazil.

ABSTRACT
Infection by the protozoan parasite Toxoplasma gondii is highly prevalent worldwide and may have serious clinical manifestations in immunocompromised patients. T. gondii is an obligate intracellular parasite that infects almost any cell type in mammalian hosts, including immune cells. The immune cells express purinergic P2 receptors in their membrane--subdivided into P2Y and P2X subfamilies--whose activation is important for infection control. Here, we examined the effect of treatment with UTP and UDP in mouse peritoneal macrophages infected with T. gondii tachyzoites. Treatment with these nucleotides reduced parasitic load by 90%, but did not increase the levels of the inflammatory mediators NO and ROS, nor did it modulate host cell death by apoptosis or necrosis. On the other hand, UTP and UDP treatments induced early egress of tachyzoites from infected macrophages, in a Ca2+-dependent manner, as shown by scanning electron microscopy analysis, and videomicroscopy. In subsequent infections, prematurely egressed parasites had reduced infectivity, and could neither replicate nor inhibit the fusion of lysosomes to the parasitophorous vacuole. The use of selective agonists and antagonists of the receptor subtypes P2Y2 and P2Y4 and P2Y6 showed that premature parasite egress may be mediated by the activation of these receptor subtypes. Our results suggest that the activity of P2Y host cell receptors controls T. gondii infection in macrophages, highlighting the importance of pyrimidinergic signaling for innate immune system response against infection. Finally the P2Y receptors should be considered as new target for the development of drugs against T. gondii infection.

No MeSH data available.


Related in: MedlinePlus