RESUMO
Schistosomiasis is a chronic disease caused by the parasite of the Schistosoma genus and is characterized by egg-induced hepatic granulomas and fibrosis. Macrophages play a central role in schistosomiasis with several studies highlighting their differentiation into M2 cells involved in the survival of infected mice through limitation of immunopathology. However, little is known regarding the mechanisms of regulating macrophage differentiation. Here, we showed that the early stage of infection by Schistosoma japonicum induced expression of type 1T-helper-cell (Th1) cytokine, interferon-γ (IFN-γ), leading to increase in M1 cells. However, the presence of liver-trapped eggs induced the expression of Th2 cytokines including interleukin-4 (IL-4), IL-10, and IL-13 that upregulated the transcription of miR-146b by activating signal transducer and activator of transcription 3/6 (STAT3/6) that bind to the promoter of the pre-miR-146b gene. We found that the miR-146a/b was significantly upregulated in macrophages during the progression of hepatic schistosomiasis. The elevated miR-146a/b inhibited the IFN-γ-induced differentiation of macrophages to M1 cells through targeting STAT1. Our data indicate the protective roles of miR-146a/b in hepatic schistosomiasis through regulating the differentiation of macrophages into M2 cells.
Assuntos
Hepatopatias Parasitárias/genética , Macrófagos/metabolismo , MicroRNAs/genética , Interferência de RNA , Fator de Transcrição STAT1/genética , Esquistossomose/genética , Animais , Citocinas/metabolismo , Modelos Animais de Doenças , Progressão da Doença , Expressão Gênica , Hepatopatias Parasitárias/parasitologia , Hepatopatias Parasitárias/patologia , Ativação de Macrófagos/genética , Ativação de Macrófagos/imunologia , Macrófagos/citologia , Macrófagos/imunologia , Masculino , Camundongos , Modelos Biológicos , Esquistossomose/parasitologia , Esquistossomose/patologia , Células Th2/imunologia , Células Th2/metabolismoRESUMO
OBJECTIVE: To determine the free thiols in the chimeric protein PfCP-2.9 of Plasmodium falciparum expressed by Pichia pastoris. METHODS: Two experiments of reverse phase HPLC and Ellman's reaction were applied to the PfCP-2.9 for the determination of its free thiols. For RP-HPLC analysis, three kinds of samples were tested: PfCP-2.9, dithiothreitol-reduced PfCP-2.9 and indoacetic acid-alkylated PfCP-2.9. RESULTS: Both experiments showed that there were no any free thiols present in the PfCP-2.9. CONCLUSION: The disulfide bonds between cysteine residues of PfCP-2.9 were formed completely.