RESUMO
OBJECTIVE: To determine the involvement of TNF-α and glycine receptors in the inhibition of pro-inflammatory adipokines in 3T3-L1 cells. METHODS: RT-PCR evidenced glycine receptors in 3T3-L1 adipocytes. 3T3-L1 cells were transfected with siRNA for the glycine (Glrb) and TNF1a (Tnfrsf1a) receptors and confirmed by confocal microscopy. Transfected cells were treated with glycine (10 mM). The expressions of TNF-α and IL-6 mRNA were measured by qRT-PCR, while concentrations were quantified by ELISA. RESULTS: Glycine decreased the expression and concentration of TNF-α and IL-6; this effect did not occur in the absence of TNF-α receptor due to siRNA. In contrast, glycine produced only slight changes in the expression of TNF-α and IL-6 in the absence of the glycine receptor due to siRNA. A docking analysis confirmed the possibility of binding glycine to the TNF-α1a receptor. CONCLUSION: These findings support the idea that glycine could partially inhibit the binding of TNF-α to its receptor and provide clues about the mechanisms by which glycine inhibits the secretion of pro-inflammatory adipokines in adipocytes through the TNF-α receptor.
Assuntos
Adipócitos/metabolismo , Citocinas/metabolismo , Glicina/farmacologia , Receptores Tipo II do Fator de Necrose Tumoral/antagonistas & inibidores , Receptores Tipo I de Fatores de Necrose Tumoral/antagonistas & inibidores , Células 3T3-L1 , Adiponectina/genética , Animais , Citocinas/genética , Expressão Gênica , Camundongos , NF-kappa B/antagonistas & inibidores , NF-kappa B/metabolismo , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/genética , Receptores de Glicina/genética , Receptores Tipo I de Fatores de Necrose Tumoral/genética , Receptores Tipo II do Fator de Necrose Tumoral/genéticaRESUMO
BACKGROUND: Cardiovascular disease is more frequent in menopausal women, which has been related to factor such as weight gain, altered fat distribution, and increased inflammation markers including adipokines (MCP-1, TNF-α, IL-6) and cytokines (IL-1, IL-6, TNF-α) produced by macrophages. In addition to their phagocytic activity, macrophages secrete cytokines and chemokines that induces cell recruitment, which is a process related to vascular damage that favors the formation of atheromatous plaques. Tibolone (Tb) therapy is used to reduce the symptoms of menopause as well as osteoporosis and it has been shown to decreases the risk of fractures. METHODS: To investigate the effect of tibolone in macrophage enzymatic activity, gene expression of cytokines, and its effect on foam cells formation. We use phorbol-12-myristate-13-acetate (PMA)-differentiated THP-1 cells. The cells were incubated 24 h and 48 h using pre and post-treatment schemes. We evaluated total ROS determination by NBT assay, expression of cytokines (IL-1ß, IL-6, TNF-α, NOS2, ARG1, TGFß) by RT-qPCR and foam cell formation in THP-1 differentiated macrophages stimulated with PMA. RESULTS: It was observed that the minor levels of total ROS determination were obtained with tibolone at 48 h in post-treatment scheme. Also, in a long term we found decrease the proinflammatory cytokines (IL-1ß, IL-6 and TNF-α). Finally, with treatment for 24 h with P4 y Tb we observed fewer LDL vesicles into macrophages cytoplasm. CONCLUSIONS: These results suggest that tibolone reduces the inflammatory process, also inhibits the foam cells formation; suggesting a possible role in reducing cardiovascular risk.