RESUMO
BACKGROUND: Pathogen-associated molecular patterns (PAMP) receptors play a key role in the early host response to viruses. In this work, we determined mRNA levels of two members of the Toll-like Receptors family, (TLR3 and TLR7) and the helicase RIG-I, all of three recognizing viral RNA products, in peripheral blood of healthy donors and hepatitis C virus (HCV) patients, to observe if their transcripts are altered in this disease. METHODS: IFN-alpha, TLR3, TLR7 and RIG-I levels in peripheral blood from healthy controls (n = 18) and chronic HCV patients (n = 18) were quantified by real-time polymerase chain reaction. RESULTS: Our results show that IFN-alpha, TLR3, TLR7 and RIG-I mRNA levels are significantly down-regulated in patients with chronic HCV infection when compared with healthy controls. We also found that the measured levels of TLR3 and TLR7, but not RIG-I, correlated significantly with those of IFN-alpha CONCLUSION: Monitoring the expression of RNA-sensing receptors like TLR3, TLR7 and RIG-I during the different clinical stages of infection could bring a new source of data about the prognosis of disease.
Assuntos
Regulação para Baixo , Hepatite C Crônica/imunologia , Leucócitos Mononucleares/metabolismo , RNA Mensageiro/metabolismo , Receptores de Reconhecimento de Padrão/metabolismo , Adulto , Idoso , Proteína DEAD-box 58 , RNA Helicases DEAD-box/genética , RNA Helicases DEAD-box/metabolismo , Feminino , Hepacivirus/imunologia , Hepacivirus/patogenicidade , Hepatite C Crônica/metabolismo , Hepatite C Crônica/virologia , Humanos , Interferon-alfa/genética , Interferon-alfa/metabolismo , Leucócitos Mononucleares/imunologia , Masculino , Pessoa de Meia-Idade , Prognóstico , RNA Mensageiro/genética , RNA Viral/metabolismo , Receptores Imunológicos , Receptores de Reconhecimento de Padrão/genética , Receptor 3 Toll-Like/genética , Receptor 3 Toll-Like/metabolismo , Receptor 7 Toll-Like/genética , Receptor 7 Toll-Like/metabolismoRESUMO
BACKGROUND: We have previously demonstrated that the synthetic retinoid N-(4-hydroxyphenyl) retinamide (4-HPR) induces the overproduction of reactive oxygen species (ROS) in human leukemia cells, which in turn triggers the intrinsic (mitochondrial) apoptotic pathway. In order to study the role of glutathione in 4-HPR-induced apoptosis, the levels of this antioxidant were analyzed in cell lines which are sensitive and resistant to the effects of 4-HPR, and the effect of the modulation of glutathione levels on 4-HPR cytotoxicity was characterized. MATERIALS AND METHODS: Mitochondrial membrane potential (deltaPsim) and the levels of glutathione were measured by flow cytometry. A fluorometric assay was used to measure intracellular ROS generation and Western blot was employed to analyze tissue transglutaminase expression. RESULTS: 4-HPR generated large quantities of ROS in cell lines which expressed low glutathione levels, these cells being the most sensitive to the retinoid. The sensitivity of leukemia cells to 4-HPR could be modulated, either by increasing intracellular glutathione contents using all-trans retinoic acid (ATRA), or by decreasing it using DL-buthionine-S,R-sulfoximine (BSO). ATRA increased the level of expression of tissue transglutaminase, whereas inhibition of this enzyme led to enhanced apoptosis. CONCLUSION: Our findings indicate that the glutathione content contributes to determining the sensitivity of cells to 4-HPR and points to the potential application of glutathione-inhibiting agents as enhancers in 4-HPR-based therapies.