Toxoplasma gondii infection of activated J774-A1 macrophages causes inducible nitric oxide synthase degradation by the proteasome pathway.
Classically activated macrophages produce nitric oxide (NO), which is a potent microbicidal agent. NO production is catalyzed by inducible nitric oxide synthase (iNOS), which uses arginine as substrate producing NO and citruline. However, it has been demonstrated that NO production is inhibited after macrophage infection of Toxoplasma gondii, the agent of toxoplasmosis, due to iNOS degradation. Three possible iNOS degradation pathways have been described in activated macrophages: proteasome, calpain and lysosomal. To identify the iNOS degradation pathway after T. gondii infection, J774-A1 macrophage cell line was activated with lipopolysaccharide and interferon-gamma for 24 h, treated with the following inhibitors, lactacystin (proteasome), calpeptin (calpain), or concanamycin A (lysosomal), and infected with the parasite. NO production and iNOS expression were evaluated after 2 and 6 h of infection. iNOS was degraded in J774-A1 macrophages infected with T. gondii. However, treatment with lactacystin maintained iNOS expression in J774-A1 macrophages infected for 2 h by T. gondii, and after 6 h iNOS was localized in aggresomes. iNOS was degraded after parasite infection of J774-A1 macrophages treated with calpeptin or concanamycin A. NO production confirmed iNOS expression profiles. These results indicate that T. gondii infection of J774-A1 macrophages caused iNOS degradation by the proteasome pathway.
Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, 28013-602 Campos dos Goytacazes, RJ, Brazil.
Juliana da Cruz
Jda C
Padrão
Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, 28013-602 Campos dos Goytacazes, RJ, Brazil.
Gabriel Rabello de Abreu
GR
Cabral
Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, 28013-602 Campos dos Goytacazes, RJ, Brazil.
Maria de Fátima Sarro
Mde F
da Silva
Laboratório de Tecnologia em Bioquímica e Microscopia, Setor Laboratorial, Centro Universitário Estadual da Zona Oeste, Avenida Manuel Caldeira de Alvarenga, 1203, Campo Grande, Rio de Janeiro, 21070-200 RJ, Brazil.
Sergio Henrique
SH
Seabra
Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, 28013-602 Campos dos Goytacazes, RJ, Brazil. Electronic address: renato@uenf.br.
Renato Augusto
RA
DaMatta
D000818:Animals; D002460:Cell Line; D002470:Cell Survival; D004151:Dipeptides / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D018942:Macrolides / Q000494:pharmacology; D008264:Macrophages / Q000469:parasitology*; D051379:Mice; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism*; D014122:Toxoplasma / Q000502:physiology*
D004151:Dipeptides; D018942:Macrolides; C071482:calpeptin; D009569:Nitric Oxide; C036978:concanamycin A; D052247:Nitric Oxide Synthase Type II; D046988:Proteasome Endopeptidase Complex
Inducible nitric oxide synthase; Macrophage; Proteasome; Toxoplasma gondii