| Tuberculosis(TB),an infectious disease caused by Mycobacterium tuberculosis(Mtb)infection,poses a long-term threat to global public health.In the process of Mtb infection,the natural immunity of the host is first activated.Dendritic cells(DCs)as specialized antigen presenting cells in the body,can activate the naive T cells and link the natural immune response with the adaptive immune response,playing an important role in Mtb infection.In recent years,with the significant increase of multidrug-resistant tuberculosis cases,interferon(IFNs)and first-line anti-TB drugs have been used in combination in clinical treatment,and good therapeutic effects have been achieved.IFNs can exert its biological effect by inducing the production of interferon-stimulated genes(ISGs)through the JAK-STAT pathway.Viperin is one of the important ISGs and has a broad-spectrum antiviral effect.Previous studies have found that Viperin can inhibit the host immune response and promote Mtb infection in macrophages,but whether Viperin is also involved in regulating the immunity of tuberculosis infection in DCs is still unknown and needs further study.Method1.Quantitative real-time PCR(qRT-PCR)and Western blot were used to detect the expression of Viperin in Mtb-infected mouse bone marrow-derived dendritic cells(BMDCs);2.The effect of Viperin on the phagocytic capacity of BMDCs was detected by flow cytometry,and the effect of Viperin on the survival of Mtb in BMDCs and mice was detected by colony-forming units experiment;3.qRT-PCR and enzyme-linked immunosorbent assay(ELISA)were used to detect the effect of Viperin on the expression of proinflammatory cytokines IL-12,TNF-α,IL-1β,IL-6 and chemokines CXCL1,CXCL2,CXCL10 in Mtb-infected BMDCs;4.qRT-PCR,Western blot and Griess-Reagent-System were used to detect the effect of Viperin on nitric oxide synthase(iNOS)expression and nitric oxide(NO)production in Mtb-infected BMDCs;5.The effect of Viperin on the expression of MHC I,MHC II and costimulatory molecules CD80,CD86,CD40 on the surface of Mtb-infected BMDCs was detected by flow cytometry;6.The effect of Viperin on the ability of BMDCs to activate T cells was detected by flow cytometry;7.Western blot was used to detect the phosphorylation levels of important signaling pathway kinases.After BMDCs were treated with nuclear factor-kappaB(NF-κB)p65 inhibitor,flow cytometry was used to detect the levels of MHC II,CD80,CD86 and CD40 expression,qRT-PCR,ELISA and Griess-Reagent-System were used to detect the recovery effect of NO,pro-inflammatory cytokines and chemokines,and flow cytometry was used to detect the phagocytic ability of BMDCs after NO inhibitor treatment.Results1.Viperin expression was significantly increased in Mtb-infected BMDCs;2.Viperin inhibits the phagocytic ability of BMDCs and promotes the survival of Mtb;3.Viperin inhibits the expression of pro-inflammatory cytokines and chemokines in Mtb-infected BMDCs;4.Viperin inhibits the expression of iNOS and the production of NO in Mtb-infected BMDCs;5.Viperin inhibits the expression of MHC Ⅰ,MHC Ⅱ and CD80,CD86,CD40 on the surface of Mtb-infected BMDCs;6.Viperin inhibits the ability of BMDCs to activate T cells;7.NF-κB p65 inhibitor partially restored the changes in NO,pro-inflammatory cytokines,chemokines and MHC II and costimulatory molecules caused by Viperin deficiency.Viperin inhibits the phagocytic ability of DCs by reducing NO production.ConclusionsThis study suggests that Mtb-induced Viperin inhibits the activation of the defense function of DCs upon Mtb infection and inhibits the interaction between DCs and T cells.This research may provide a new target for future treatment of tuberculosis. |
