RESUMO
Human T lymphotropic virus type 1 (HTLV-1) belongs to the deltaretrovirus family and has been linked to multiple diseases. However, the innate host defense against HTLV-1 is unclear. In this study, we report that the expression of Ku70, a known DNA sensor against DNA viruses, could be induced by HTLV-1 infection in HeLa, PMA-differentiated THP1 cells, primary human monocytes, and human monocyte-derived macrophages. In these cells, the overexpression of Ku70 inhibited the HTLV-1 protein expression, whereas the knockdown of Ku70 promoted the HTLV-1 protein expression. Furthermore, the overexpression of Ku70 enhanced the cellular response to HTLV-1 infection, whereas Ku70 knockdown yielded the opposite effect. Additionally, Ku70 was found to interact with HTLV-1 reverse transcription intermediate ssDNA90. ssDNA90 stimulation induced Ku70 expression and Ku70 promoted ssDNA90-triggered innate immune responses. Finally, HTLV-1 infection enhanced the association between Ku70 and stimulator of IFN genes, suggesting that stimulator of IFN genes was involved in Ku70-mediated host defenses against HTLV-1 infection. Taken together, our findings suggest a new sensor that detects HTLV-1 reverse transcription intermediate and controls HTLV-1 replication. These findings may provide new angles to understand host defenses against HTLV-1 infection and HTLV-1-associated diseases.
Assuntos
DNA Viral , Vírus Linfotrópico T Tipo 1 Humano/fisiologia , Autoantígeno Ku/genética , Autoantígeno Ku/metabolismo , Replicação Viral , Células Cultivadas , Produtos do Gene tax/genética , Células HeLa , Vírus Linfotrópico T Tipo 1 Humano/genética , Vírus Linfotrópico T Tipo 1 Humano/imunologia , Humanos , Imunidade Inata , Interferons/genética , Interferons/imunologia , Autoantígeno Ku/deficiência , Autoantígeno Ku/imunologia , Macrófagos/virologia , Monócitos/virologia , Produtos do Gene gag do Vírus da Imunodeficiência Humana/genéticaRESUMO
In previous studies, we found interferon-α (IFN-α) could reduce protein levels of p11, 5-hydroxytryptamine receptor 1b (5-HT1b) and 5-hydroxytryptamine receptor 4 (5-HT4), but does not influence their messenger RNA levels in SH-sy5y cells. Thus, we investigated the post-transcriptional modulation of these molecules by IFN-α. SH-sy5y cells were treated with IFN-α, NH4Cl or MG132 alone or in combination, and then the protein levels of p11, 5-HT1b and 5-HT4 were analyzed by western blots. The regulatory effects of p11 on 5-HT1b and 5-HT4 were also determined in p11 knock-down cells. NH4Cl but not MG132 could reverse the protein level of p11 in IFN-α-treated SH-sy5y cells. MG132 could recover the protein levels of 5-HT1b and 5-HT4 in p11 knock-down cells. The down-regulation effects of IFN-α on p11, 5-HT1b and 5-HT4 were associated with the lysosome and ubiquitin-proteasome-mediated pathways. p11 was identified as a potent regulator to modulate the ubiquitination of 5-HT1b and 5-HT4. Therefore, it could be potential target therapies in IFN-ainduced depression.
Assuntos
Depressão/tratamento farmacológico , Interferon-alfa/farmacologia , Receptor 5-HT1B de Serotonina/genética , Cloreto de Amônio/farmacologia , Linhagem Celular Tumoral , Peptídeos Penetradores de Células/genética , Depressão/genética , Depressão/patologia , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Leupeptinas/farmacologia , Lisossomos/efeitos dos fármacos , Lisossomos/genética , Proteólise , RNA Mensageiro/genética , Proteínas Recombinantes/farmacologia , Transdução de Sinais/efeitos dos fármacos , UbiquitinaRESUMO
Depression is one of the major side effects of interferon alpha (IFN-α) treatment, but the molecular mechanism underlying IFN-α-induced depression remains unclear. Several studies have shown that the serotonin receptors 5-HTR1b and 5-HTR4 play key roles in the anti-depression effects associated with p11 (S100A10). We investigated the effects of IFN-α on the regulation of p11, 5-HTR1b and 5-HTR4 in mice and human neuroblastoma cells (SH-sy5y). We found that intraperitoneal injection with IFN-α in Balb/c mice resulted in an increased immobility in FST and TST, and potently lowered the protein levels of p11, 5-HTR1b and 5-HTR4 in the hippocampus or cingulate gyrus. IFN-α significantly down-regulated the protein levels of p11, 5-HTR1b and 5-HTR4 in SH-sy5y cells, in a time- and dose-dependent manner. Our study revealed that over-expression of p11 could prevent the IFN-α-induced down-regulation of 5-HTR1b and 5-HTR4. The results indicated that IFN-α treatment resulted in p11 down-regulation, which subsequently decreased 5-HTR1b and 5-HTR4 in vitro or in vivo. Our findings suggested that p11 might be a potential regulator on 5-HTR1b and 5-HTR4 as well as a predictor of or a therapeutic target for IFN-α-induced depression.