RESUMO
Replication of lentiviruses generates different DNA forms, including RNA:DNA hybrids, ssDNA, and dsDNA. Nucleic acids stimulate innate immune responses, and pattern recognition receptors detecting dsDNA have been identified. However, sensors for ssDNA have not been reported, and the ability of RNA:DNA hybrids to stimulate innate immune responses is controversial. Using ssDNAs derived from HIV-1 proviral DNA, we report that this DNA form potently induces the expression of IFNs in primary human macrophages. This response was stimulated by stem regions in the DNA structure and was dependent on IFN-inducible protein 16 (IFI16), which bound immunostimulatory DNA directly and activated the stimulator of IFN genes -TANK-binding kinase 1 - IFN regulatory factors 3/7 (STING-TBK1-IRF3/7) pathway. Importantly, IFI16 colocalized and associated with lentiviral DNA in the cytoplasm in macrophages, and IFI16 knockdown in this cell type augmented lentiviral transduction and also HIV-1 replication. Thus, IFI16 is a sensor for DNA forms produced during the lentiviral replication cycle and regulates HIV-1 replication in macrophages.
Assuntos
DNA Viral/metabolismo , HIV-1/fisiologia , Imunidade Inata/imunologia , Proteínas de Membrana/metabolismo , Proteínas Nucleares/metabolismo , Fosfoproteínas/metabolismo , Transdução de Sinais/imunologia , Replicação Viral/fisiologia , Técnicas de Silenciamento de Genes , Humanos , Hibridização in Situ Fluorescente , Macrófagos/metabolismo , Microscopia Confocal , Proteínas Nucleares/genética , Fosfoproteínas/genéticaRESUMO
In recent decades, the treatment of autoimmune diseases has moved from the use of hormones and conventional immunosuppressive drugs to biological agents. B cell proliferation and maturation play crucial roles in the development of autoimmune diseases. The tumor necrosis factor superfamily ligand B cell activating factor (BAFF) and its receptor mediate B cell survival through regulating signaling pathways. Therefore, BAFF and its receptors are important therapeutic targets for the treatment of autoimmune diseases. This review describes the mechanism of BAFF and its receptor in the human body system and introduces the latest views on how over-activation of BAFF pathway promotes the development of autoimmune diseases including systemic lupus erythematosus, Sjogren's syndrome, and rheumatoid arthritis. In connection to the treatment of the above three diseases, this review discusses the clinical trials and application status of three BAFF-targeting antibody drugs, including Belimumab, Tabalumab and Atacicept. Finally, this review proposes new strategies that targeting the BAFF pathway to provide a new treatment for autoimmune diseases.