RESUMEN
Nipah virus (NiV; genus: Henipavirus; family: Paramyxoviridae) naturally infects Old World fruit bats (family Pteropodidae) without causing overt disease. Conversely, NiV infection in humans and other mammals can be lethal. Comparing bat antiviral responses with those of humans may illuminate the mechanisms that facilitate bats' tolerance. Tripartite motif proteins (TRIMs), a large family of E3-ubiquitin ligases, fine-tune innate antiviral immune responses, and two human TRIMs interact with Henipavirus proteins. We hypothesize that NiV infection induces the expression of an immunosuppressive TRIM in bat, but not human cells, to promote tolerance. Here, we show that TRIM40 is an interferon-stimulated gene (ISG) in pteropodid but not human cells. Knockdown of bat TRIM40 increases gene expression of IFNß, ISGs, and pro-inflammatory cytokines following poly(I:C) transfection. In Pteropus vampyrus, but not human cells, NiV induces TRIM40 expression within 16 h after infection, and knockdown of TRIM40 correlates with reduced NiV titers as compared to control cells. Bats may have evolved to express TRIM40 in response to viral infections to control immunopathogenesis.
Asunto(s)
Quirópteros , Proteína 58 DEAD Box , Infecciones por Henipavirus , Proteínas de Motivos Tripartitos , Animales , Humanos , Quirópteros/inmunología , Quirópteros/virología , Inmunidad Innata , Interferones/genética , Virus Nipah/genética , Proteínas de Motivos Tripartitos/metabolismo , Proteína 58 DEAD Box/antagonistas & inhibidores , Proteína 58 DEAD Box/metabolismoRESUMEN
IMPORTANCE: Type I interferon (IFN-I), produced by the innate immune system, plays an essential role in host antiviral responses. Proper regulation of IFN-I production is required for the host to balance immune responses and prevent superfluous inflammation. IFN regulatory factor 3 (IRF3) and subsequent sensors are activated by RNA virus infection to induce IFN-I production. Therefore, proper regulation of IRF3 serves as an important way to control innate immunity and viral replication. Here, we first identified Prohibitin1 (PHB1) as a negative regulator of host IFN-I innate immune responses. Mechanistically, PHB1 inhibited the nucleus import of IRF3 by impairing its binding with importin subunit alpha-1 and importin subunit alpha-5. Our study demonstrates the mechanism by which PHB1 facilitates the replication of multiple RNA viruses and provides insights into the negative regulation of host immune responses.
Asunto(s)
Proteína 58 DEAD Box , Prohibitinas , Virus ARN , Receptores Inmunológicos , Transducción de Señal , Replicación Viral , Proteína 58 DEAD Box/antagonistas & inhibidores , Proteína 58 DEAD Box/metabolismo , Inmunidad Innata , Factor 3 Regulador del Interferón/metabolismo , Carioferinas/metabolismo , Prohibitinas/metabolismo , Receptores Inmunológicos/antagonistas & inhibidores , Receptores Inmunológicos/metabolismo , Interferón Tipo I/biosíntesis , Interferón Tipo I/inmunología , Virus ARN/crecimiento & desarrollo , Virus ARN/inmunología , Virus ARN/metabolismoRESUMEN
RIG-I-like receptors (RLRs) are involved in the discrimination of self versus non-self via the recognition of double-stranded RNA (dsRNA). Emerging evidence suggests that immunostimulatory dsRNAs are ubiquitously expressed but are disrupted or sequestered by cellular RNA binding proteins (RBPs). TDP-43 is an RBP associated with multiple neurological disorders and is essential for cell viability. Here, we demonstrate that TDP-43 regulates the accumulation of immunostimulatory dsRNA. The immunostimulatory RNA is identified as RNA polymerase III transcripts, including 7SL and Alu retrotransposons, and we demonstrate that the RNA-binding activity of TDP-43 is required to prevent immune stimulation. The dsRNAs activate a RIG-I-dependent interferon (IFN) response, which promotes necroptosis. Genetic inactivation of the RLR-pathway rescues the interferon-mediated cell death associated with loss of TDP-43. Collectively, our study describes a role for TDP-43 in preventing the accumulation of endogenous immunostimulatory dsRNAs and uncovers an intricate relationship between the control of cellular gene expression and IFN-mediated cell death.
Asunto(s)
Proteína 58 DEAD Box/genética , Proteínas de Unión al ADN/genética , Herpesvirus Humano 8/genética , Necroptosis/genética , ARN Bicatenario/genética , Receptores Inmunológicos/genética , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/inmunología , Elementos Alu , Línea Celular Tumoral , Supervivencia Celular , Citocinas/genética , Citocinas/inmunología , Proteína 58 DEAD Box/antagonistas & inhibidores , Proteína 58 DEAD Box/inmunología , Proteínas de Unión al ADN/deficiencia , Proteínas de Unión al ADN/inmunología , Células Epiteliales/inmunología , Células Epiteliales/virología , Regulación de la Expresión Génica , Células HEK293 , Herpesvirus Humano 8/crecimiento & desarrollo , Herpesvirus Humano 8/inmunología , Humanos , Inmunización , Interferones/genética , Interferones/inmunología , Interleucina-6/genética , Interleucina-6/inmunología , Necroptosis/inmunología , Neuronas/inmunología , Neuronas/virología , ARN Polimerasa III/genética , ARN Polimerasa III/inmunología , ARN Bicatenario/inmunología , ARN Mensajero/genética , ARN Mensajero/inmunología , ARN Citoplasmático Pequeño/genética , ARN Citoplasmático Pequeño/inmunología , ARN Viral/genética , ARN Viral/inmunología , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/inmunología , Receptores Inmunológicos/antagonistas & inhibidores , Receptores Inmunológicos/inmunología , Partícula de Reconocimiento de Señal/genética , Partícula de Reconocimiento de Señal/inmunología , Transducción de Señal , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/inmunología , Ubiquitinas/genética , Ubiquitinas/inmunologíaRESUMEN
ETHNOPHARMACOLOGICAL RELEVANCE: Carvacrol, a monoterpene phenol from Mosla chinensis Maxim, which is a commonly Chinese herbal medicine. The most important pharmacology of it is dispelling exogenous evils by increasing perspiration. And it is the gentleman medicine in the Chinese herbal compound prescription of Xin-Jia-Xiang-Ru-Yin, mainly for the treatment of summer colds with dampness including influenza virus A infection. AIM OF THE STUDY: Our preliminary study verified that the Xin-Jia-Xiang-Ru-Yin could inhibit acute lung injury of mice with influenza virus A infection. And there have been some reports implicating the high antimicrobial activity of carvacrol for a wide range of product preservation, but little research including the effects of it on viral infection. The aim of this study was to reveal the antiviral effects of carvacrol, the main constituent in Mosla chinensis Maxim. MATERIALS AND METHODS: Initially, C57BL/6 mice were grouped and intranasally administered FM1 virus to construct viral infection models. After treatment with ribavirin and carvacrol for 5 days, all mice were euthanized, and specimens were immediately obtained. Histology, flow cytometry and Meso Scale Discovery (MSD) analysis were used to analyze pathological changes in lung tissue, the expression levels of cytokines and the differentiation and proportion of CD4+ T cells subsets, while Western blot and qRT-PCR were used to detect the expression of related proteins and mRNA. RESULTS: Carvacrol attenuated lung tissue damage, the proportions of Th1, Th2, Th17 and Treg in CD4+ T cells and the relative proportions of Th1/Th2 and Th17/Treg cells. Carvacrol inhibited the expression of inflammation-associated cytokines including IFN-γ, IL-2, IL-4, IL-5, IL-12 and TNF-É, IL-1, IL-10, IL-6. Decreased levels of TLR7, MyD88, IRAK4, TRAK6, NF-κB, RIG-I, IPS-I and IRF mRNA in carvacrol-treated mice were observed comparing to the mice in VC group. Further, the total expression of RIG-I, MyD88 and NF-κB proteins had increased significantly in the VC group but reduced obviously in the group treated with ribavirin or carvacrol. CONCLUSIONS: These results indicate that carvacrol is a potential alternative treatment for the excessive immune response induced by influenza virus A infection, the cold-fighting effect of Mosla chinensis Maxim may depend on the anti-virus of carvacrol.
Asunto(s)
Alphainfluenzavirus/efectos de los fármacos , Cimenos/farmacología , Proteína 58 DEAD Box/antagonistas & inhibidores , Inmunidad Innata/efectos de los fármacos , Glicoproteínas de Membrana/antagonistas & inhibidores , Receptor Toll-Like 7/antagonistas & inhibidores , Replicación Viral/efectos de los fármacos , Lesión Pulmonar Aguda/tratamiento farmacológico , Lesión Pulmonar Aguda/inmunología , Lesión Pulmonar Aguda/metabolismo , Animales , Cimenos/uso terapéutico , Proteína 58 DEAD Box/inmunología , Proteína 58 DEAD Box/metabolismo , Femenino , Inmunidad Innata/inmunología , Alphainfluenzavirus/inmunología , Alphainfluenzavirus/metabolismo , Glicoproteínas de Membrana/inmunología , Glicoproteínas de Membrana/metabolismo , Ratones , Ratones Endogámicos C57BL , Linfocitos T Colaboradores-Inductores/efectos de los fármacos , Linfocitos T Colaboradores-Inductores/inmunología , Linfocitos T Colaboradores-Inductores/metabolismo , Receptor Toll-Like 7/inmunología , Receptor Toll-Like 7/metabolismo , Replicación Viral/inmunologíaRESUMEN
Type I interferon (IFN)-mediated antiviral responses are critical for modulating host-virus responses, and indeed, viruses have evolved strategies to antagonize this pathway. Encephalomyocarditis virus (EMCV) is an important zoonotic pathogen, which causes myocarditis, encephalitis, neurological disease, reproductive disorders, and diabetes in pigs. This study aims to understand how EMCV interacts with the IFN pathway. EMCV circumvents the type I IFN response by expressing proteins that antagonize cellular innate immunity. Here, we show that EMCV VP2 is a negative regulator of the IFN-ß pathway. This occurs via the degradation of the MDA5-mediated cytoplasmic double-stranded RNA (dsRNA) antiviral sensing RIG-I-like receptor (RLR) pathway. We show that structural protein VP2 of EMCV interacts with MDA5, MAVS, and TBK1 through its C terminus. In addition, we found that EMCV VP2 could significantly degrade RLRs by the proteasomal and lysosomal pathways. For the first time, EMCV VP2 was shown to play an important role in EMCV evasion of the type I IFN signaling pathway. This study expands our understanding that EMCV utilizes its capsid protein VP2 to evade the host antiviral response.IMPORTANCE Encephalomyocarditis virus is an important pathogen that can cause encephalitis, myocarditis, neurological diseases, and reproductive disorders. It also causes huge economic losses for the swine industry worldwide. Innate immunity plays an important role in defending the host from pathogen infection. Understanding pathogen microorganisms evading the host immune system is of great importance. Currently, whether EMCV evades cytosolic RNA sensing and signaling is still poorly understood. In the present study, we found that viral protein VP2 antagonized the RLR signaling pathway by degrading MDA5, MAVS, and TBK1 protein expression to facilitate viral replication in HEK293 cells. The findings in this study identify a new mechanism for EMCV evading the host's innate immune response, which provide new insights into the virus-host interaction and help develop new antiviral approaches against EMCV.
Asunto(s)
Proteínas de la Cápside/metabolismo , Virus de la Encefalomiocarditis/fisiología , Interferón beta/metabolismo , Transducción de Señal , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Proteínas de la Cápside/química , Proteínas de la Cápside/genética , Infecciones por Cardiovirus/inmunología , Infecciones por Cardiovirus/virología , Proteína 58 DEAD Box/antagonistas & inhibidores , Proteína 58 DEAD Box/metabolismo , Virus de la Encefalomiocarditis/genética , Virus de la Encefalomiocarditis/metabolismo , Células HEK293 , Humanos , Evasión Inmune , Inmunidad Innata , Interferón Tipo I/metabolismo , Helicasa Inducida por Interferón IFIH1/metabolismo , Mutación , Dominios y Motivos de Interacción de Proteínas , Proteínas Serina-Treonina Quinasas/metabolismo , Receptores Inmunológicos/antagonistas & inhibidores , Receptores Inmunológicos/metabolismo , Replicación ViralRESUMEN
Immunotherapy (IO) has revolutionized the therapy landscape of non-small cell lung cancer (NSCLC), significantly prolonging the overall survival (OS) of advanced stage patients. Over the recent years IO therapy has been broadly integrated into the first-line setting of non-oncogene driven NSCLC, either in combination with chemotherapy, or in selected patients with PD-L1high expression as monotherapy. Still, a significant proportion of patients suffer from disease progression. A better understanding of resistance mechanisms depicts a central goal to avoid or overcome IO resistance and to improve patient outcome.We here review major cellular and molecular pathways within the tumor microenvironment (TME) that may impact the evolution of IO resistance. We summarize upcoming treatment options after IO resistance including novel IO targets (e.g. RIG-I, STING) as well as interesting combinational approaches such as IO combined with anti-angiogenic agents or metabolic targets (e.g. IDO-1, adenosine signaling, arginase). By discussing the fundamental mode of action of IO within the TME, we aim to understand and manage IO resistance and to seed new ideas for effective therapeutic IO concepts.
Asunto(s)
Antígeno B7-H1/genética , Carcinoma de Pulmón de Células no Pequeñas/terapia , Proteína 58 DEAD Box/genética , Inmunoterapia/efectos adversos , Proteínas de la Membrana/genética , Receptores Inmunológicos/genética , Arginasa/genética , Antígeno B7-H1/antagonistas & inhibidores , Antígeno B7-H1/inmunología , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/inmunología , Proteína 58 DEAD Box/antagonistas & inhibidores , Proteína 58 DEAD Box/inmunología , Resistencia a Antineoplásicos/genética , Resistencia a Antineoplásicos/inmunología , Humanos , Indolamina-Pirrol 2,3,-Dioxigenasa/genética , Proteínas de la Membrana/antagonistas & inhibidores , Proteínas de la Membrana/inmunología , Receptores Inmunológicos/antagonistas & inhibidores , Receptores Inmunológicos/inmunología , Microambiente Tumoral/efectos de los fármacos , Microambiente Tumoral/inmunologíaRESUMEN
BACKGROUND: Interferon-α (IFN-α) plays a pivotal role in host antitumor immunity, and the evasion of IFN-α signaling pathway can lead to IFN-α resistance during the treatment of cancer. Although the interplay between IFN-α and tumor cells has been extensively investigated in differentiated tumor cells, much less attention has been directed to tumor-repopulating cells (TRCs). METHODS: Three-dimentional soft fibrin matrix was used to select and grow highly malignant and tumorigenic melanoma TRCs. The regulation of integrin ß3 (ITGB3)-c-SRC-STAT signaling pathway in melanoma TRCs was investigated both in vitro and in vivo. The relevant mRNA and protein expression levels were analyzed by qRT-PCR and western blot analysis. Immunoprecipitation and chromatin immunoprecipitation (ChIP) followed by qPCR (ChIP-qPCR) assays were performed to detect protein-protein and protein-DNA interactions. The clinical impacts of retinoic acid inducible gene-I (RIG-I) were assessed in melanoma datasets obtained from The Cancer Genome Atlas and Gene Expression Omnibus profiles. RESULTS: IFN-α-induced apoptosis was decreased in melanoma TRCs. Compared with conventional flask-cultured cells, IFN-α-mediated STAT1 activation was diminished in melanoma TRCs. Decreased expression of RIG-I in melanoma TRCs led to diminished activation of STAT1 via enhancing the interaction between Src homology region 2 domain-containing phosphatase-1 and STAT1. In addition, low expression levels of RIG-I correlated with poor prognosis in patients with melanoma. STAT3 was highly phosphorylated in TRCs and knockdown of STAT3 reversed the downregulation of RIG-I in TRCs. Knockdown of STAT3 resulted in STAT1 activation and increased expression of the pro-apoptosis genes in IFN-α-treated TRCs. Combined treatment of STAT3 inhibitor and IFN-α increased the apoptosis rate of TRCs. Disruption of ITGB3/c-SRC/STAT3 signaling pathway significantly elevated the efficiency of IFN-α-induced apoptosis of TRCs. CONCLUSIONS: In melanoma TRCs, ITGB3-c-SRC-STAT3 pathway caused RIG-I repression and then affect STAT1 activation to cause resistance to IFN-α-induced apoptosis. RIG-I is a prognostic marker in patients with melanoma. Combination of STAT3 inhibitor and IFN-α could enhance the efficacy of melanoma treatment. Our findings may provide a new concept of combinatorial treatment for future immunotherapy.
Asunto(s)
Proteína 58 DEAD Box/metabolismo , Integrina beta3/metabolismo , Interferón-alfa/farmacología , Melanoma Experimental/tratamiento farmacológico , Melanoma/tratamiento farmacológico , Proteínas Proto-Oncogénicas pp60(c-src)/metabolismo , Factor de Transcripción STAT3/metabolismo , Animales , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Proteína 58 DEAD Box/antagonistas & inhibidores , Proteína 58 DEAD Box/genética , Regulación hacia Abajo , Femenino , Células Hep G2 , Humanos , Factores Inmunológicos/farmacología , Melanoma/inmunología , Melanoma/metabolismo , Melanoma/patología , Melanoma Experimental/inmunología , Melanoma Experimental/metabolismo , Melanoma Experimental/patología , Ratones , Ratones Endogámicos C57BL , Pronóstico , Receptores Inmunológicos , Factor de Transcripción STAT1/metabolismo , Transducción de Señal , Tasa de SupervivenciaRESUMEN
The host protective immunity against viral infection requires the effective detection of viral antigens and the subsequent production of type I interferons (IFNs) by host immune cells. Retinoic acid-inducible gene I (RIG-I) is the crucial signaling element responsible for sensing viral RNA component and initiating the downstream antiviral signaling pathways, leading to the production of type I IFNs. In this work, we identified microRNA-218 (miR-218) as a new virus-induced miRNA that dampens the expression of RIG-I in mouse and human macrophages, leading to the impaired production of type I IFNs. Interfering miR-218 expression rescued RIG-I-mediated antiviral signaling and thus protected macrophages from viral infection. Hence, our results provide new understanding of miRNA-mediated viral immune evasion and may be potentially useful for the treatment of viral infection in the future.
Asunto(s)
Antivirales/farmacología , Proteína 58 DEAD Box/antagonistas & inhibidores , Interferón Tipo I/antagonistas & inhibidores , Macrófagos/efectos de los fármacos , MicroARNs/inmunología , Vesiculovirus/efectos de los fármacos , Animales , Antivirales/inmunología , Células Cultivadas , Proteína 58 DEAD Box/inmunología , Evasión Inmune/efectos de los fármacos , Evasión Inmune/inmunología , Interferón Tipo I/biosíntesis , Macrófagos/inmunología , Macrófagos/virología , Masculino , Ratones , Ratones Endogámicos C57BL , MicroARNs/genética , Pruebas de Sensibilidad MicrobianaRESUMEN
The RIG-I receptor plays a key role in the vertebrate innate immune system, where it functions as a sensor for detecting infection by RNA viruses. Although agonists of RIG-I show great potential as antitumor and antimicrobial therapies, antagonists of RIG-I remain undeveloped, despite the role of RIG-I hyperstimulation in a range of diseases, including COPD and autoimmune disorders. There is now a wealth of information on RIG-I structure, enzymatic function, and signaling mechanism that can drive new drug design strategies. Here, we used the enzymatic activity of RIG-I to develop assays for high-throughput screening, SAR, and downstream optimization of RIG-I antagonists. Using this approach, we have developed potent RIG-I antagonists that interact directly with the receptor and which inhibit RIG-I signaling and interferon response in living cells.
Asunto(s)
Proteína 58 DEAD Box/antagonistas & inhibidores , Indoles/farmacología , Receptores Inmunológicos/antagonistas & inhibidores , Células A549 , Células HEK293 , Ensayos Analíticos de Alto Rendimiento , Humanos , Indoles/química , Estructura Molecular , Transducción de Señal/efectos de los fármacos , Relación Estructura-ActividadRESUMEN
Swine acute diarrhea syndrome coronavirus (SADS-CoV), a newly emerging enteric coronavirus, is considered to be associated with swine acute diarrhea syndrome (SADS) which has caused significantly economic losses to the porcine industry. Interactions between SADS-CoV and the host innate immune response is unclear yet. In this study, we used IPEC-J2 cells as a model to explore potential evasion strategies employed by SADS-CoV. Our results showed that SADS-CoV infection failed to induce IFN-ß production, and inhibited poly (I:C) and Sendai virus (SeV)-triggered IFN-ß expression. SADS-CoV also blocked poly (I:C)-induced phosphorylation and nuclear translocation of IRF-3 and NF-κB. Furthermore, SADS-CoV did not interfere with the activity of IFN-ß promoter stimulated by IRF3, TBK1 and IKKε, but counteracted its activation induced by IPS-1 and RIG-I. Collectively, this study is the first investigation that shows interactions between SADS-CoV and the host innate immunity, which provides information of the molecular mechanisms underlying SASD-CoV infection.
Asunto(s)
Alphacoronavirus/fisiología , Infecciones por Coronavirus/inmunología , Proteína 58 DEAD Box/antagonistas & inhibidores , Interferón beta/antagonistas & inhibidores , Transporte Activo de Núcleo Celular , Animales , Línea Celular , Núcleo Celular/metabolismo , Infecciones por Coronavirus/virología , Proteína 58 DEAD Box/metabolismo , Interacciones Huésped-Patógeno/inmunología , Inmunidad Innata , Factor 3 Regulador del Interferón/metabolismo , Interferón beta/genética , Interferón beta/metabolismo , FN-kappa B/metabolismo , Fosforilación , Regiones Promotoras Genéticas , Transducción de Señal , PorcinosRESUMEN
Zika virus (ZIKV) is a mosquito-transmitted, emerging Flavivirus that causes Guillain-Barré syndrome and microcephaly in adults and fetuses, respectively. Since ZIKV was first isolated in 1947, severe outbreaks have occurred at various places worldwide, including Yap Island in 2007, French Polynesia in 2013, and Brazil in 2015. Although incidences of ZIKV infection and dissemination have drastically increased, the mechanisms underlying the pathogenesis of ZIKV have not been sufficiently studied. In addition, despite extensive research, the exact roles of individual ZIKV genes in the viral evasion of the host innate immune responses remain elusive. Besides, it is still possible that more than one ZIKV-encoded protein may negatively affect type I interferon (IFN) induction. Hence, in this study, we aimed to determine the modulations of the IFN promoter activity, induced by the MDA5/RIG-I signaling pathway, by over-expressing individual ZIKV genes. Our results show that two nonstructural proteins, NS2A and NS4A, significantly down-regulated the promoter activity of IFN-ß by inhibiting multiple signaling molecules involved in the activation of IFN-ß. Interestingly, while NS2A suppressed both full-length and constitutively active RIG-I, NS4A had inhibitory activity only on full-length RIG-I. In addition, while NS2A inhibited all forms of IRF3 (full-length, regulatory domain-deficient, and constitutively active), NS4A could not inhibit constitutively active IRF3-5D. Taken together, our results showed that NS2A and NS4A play major roles as antagonists of MDA5/RIG-I-mediated IFN-ß induction and more importantly, these two viral proteins seem to inhibit induction of the type I IFN responses in differential mechanisms. We believe this study expands our understanding regarding the mechanisms via which ZIKV controls the innate immune responses in cells and may pave the way to development of ZIKV-specific therapeutics.
Asunto(s)
Proteína 58 DEAD Box/metabolismo , Helicasa Inducida por Interferón IFIH1/metabolismo , Interferón beta/genética , Proteínas no Estructurales Virales/metabolismo , Virus Zika/inmunología , Proteína 58 DEAD Box/antagonistas & inhibidores , Células HEK293 , Interacciones Huésped-Patógeno , Humanos , Evasión Inmune , Factor 3 Regulador del Interferón/antagonistas & inhibidores , Factor 3 Regulador del Interferón/metabolismo , Helicasa Inducida por Interferón IFIH1/antagonistas & inhibidores , Regiones Promotoras Genéticas , Receptores Inmunológicos , Transducción de Señal , Proteínas no Estructurales Virales/genéticaRESUMEN
14-3-3 protein family members facilitate the translocation of RIG-I-like receptors (RLRs) to organelles that mediate downstream RLR signaling, leading to interferon production. 14-3-3ϵ promotes the cytosolic-to-mitochondrial translocation of RIG-I, while 14-3-3η facilitates MDA5 translocation to mitochondria. We show that the NS3 protein of Zika virus (ZIKV) antagonizes antiviral gene induction by RIG-I and MDA5 by binding to and sequestering the scaffold proteins 14-3-3ϵ and 14-3-3η. 14-3-3-binding is mediated by a negatively charged RLDP motif in NS3 that is conserved in ZIKV strains of African and Asian lineages and is similar to the one found in dengue and West Nile viruses. ZIKV NS3 is sufficient to inhibit the RLR-14-3-3ϵ/η interaction and to suppress antiviral signaling. Mutational perturbation of 14-3-3ϵ/η binding in a recombinant ZIKV leads to enhanced innate immune responses and impaired growth kinetics. Our study provides molecular understanding of immune evasion functions of ZIKV, which may guide vaccine and anti-flaviviral therapy development.
Asunto(s)
Proteínas 14-3-3/metabolismo , Evasión Inmune/inmunología , Péptido Hidrolasas/metabolismo , Proteínas Virales/metabolismo , Infección por el Virus Zika/inmunología , Virus Zika/inmunología , Células A549 , Animales , Línea Celular , Chlorocebus aethiops , Proteína 58 DEAD Box/antagonistas & inhibidores , Células HEK293 , Células HeLa , Humanos , Inmunidad Innata/inmunología , Helicasa Inducida por Interferón IFIH1/antagonistas & inhibidores , Interferón beta/inmunología , Mitocondrias/metabolismo , Péptido Hidrolasas/genética , Interferencia de ARN , ARN Interferente Pequeño/genética , Receptores Inmunológicos , Serina Endopeptidasas , Células Vero , Proteínas Virales/genética , Virus Zika/genéticaRESUMEN
RIG-I is a cytosolic RNA sensor that recognizes short 5' triphosphate RNA, commonly generated during virus infection. Upon activation, RIG-I initiates antiviral immunity, and in some circumstances, induces cell death. Because of this dual capacity, RIG-I has emerged as a promising target for cancer immunotherapy. Previously, a sequence-optimized RIG-I agonist (termed M8) was generated and shown to stimulate a robust immune response capable of blocking viral infection and to function as an adjuvant in vaccination strategies. Here, we investigated the potential of M8 as an anti-cancer agent by analyzing its ability to induce cell death and activate the immune response. In multiple cancer cell lines, M8 treatment strongly activated caspase 3-dependent apoptosis, that relied on an intrinsic NOXA and PUMA-driven pathway that was dependent on IFN-I signaling. Additionally, cell death induced by M8 was characterized by the expression of markers of immunogenic cell death-related damage-associated molecular patterns (ICD-DAMP)-calreticulin, HMGB1 and ATP-and high levels of ICD-related cytokines CXCL10, IFNß, CCL2 and CXCL1. Moreover, M8 increased the levels of HLA-ABC expression on the tumor cell surface, as well as up-regulation of genes involved in antigen processing and presentation. M8 induction of the RIG-I pathway in cancer cells favored dendritic cell phagocytosis and induction of co-stimulatory molecules CD80 and CD86, together with increased expression of IL12 and CXCL10. Altogether, these results highlight the potential of M8 in cancer immunotherapy, with the capacity to induce ICD-DAMP on tumor cells and activate immunostimulatory signals that synergize with current therapies.
Asunto(s)
Antineoplásicos/uso terapéutico , Células Dendríticas/inmunología , Melanoma/tratamiento farmacológico , Nelfinavir/análogos & derivados , Alarminas/inmunología , Presentación de Antígeno/efectos de los fármacos , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Proteínas Reguladoras de la Apoptosis/metabolismo , Calreticulina/metabolismo , Caspasa 3/metabolismo , Diferenciación Celular , Línea Celular Tumoral , Proteína 58 DEAD Box/antagonistas & inhibidores , Proteína HMGB1/metabolismo , Humanos , Inmunización , Interferones/metabolismo , Terapia Molecular Dirigida , Nelfinavir/farmacología , Nelfinavir/uso terapéutico , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Receptores Inmunológicos , Transducción de SeñalRESUMEN
Recognition of viral RNA by the retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs), including RIG-I and MDA5, initiates innate antiviral responses. Although regulation of RLR-mediated signal transduction has been extensively investigated, how the recognition of viral RNA by RLRs is regulated remains enigmatic. In this study, we identified heterogeneous nuclear ribonucleoprotein M (hnRNPM) as a negative regulator of RLR-mediated signaling. Overexpression of hnRNPM markedly inhibited RNA virus-triggered innate immune responses. Conversely, hnRNPM-deficiency increased viral RNA-triggered innate immune responses and inhibited replication of RNA viruses. Viral infection caused translocation of hnRNPM from the nucleus to the cytoplasm. hnRNPM interacted with RIG-I and MDA5, and impaired the binding of the RLRs to viral RNA, leading to inhibition of innate antiviral response. Our findings suggest that hnRNPM acts as an important decoy for excessive innate antiviral immune response.
Asunto(s)
Proteína 58 DEAD Box/antagonistas & inhibidores , Ribonucleoproteína Heterogénea-Nuclear Grupo M/metabolismo , Infecciones por Virus ARN/inmunología , Virus ARN/inmunología , ARN Viral/metabolismo , Replicación Viral/inmunología , Proteína 58 DEAD Box/genética , Proteína 58 DEAD Box/metabolismo , Células HEK293 , Células HeLa , Ribonucleoproteína Heterogénea-Nuclear Grupo M/genética , Humanos , Unión Proteica , Infecciones por Virus ARN/metabolismo , Infecciones por Virus ARN/virología , ARN Viral/genética , Transducción de SeñalRESUMEN
RLR-mediated type I IFN production plays a pivotal role in elevating host immunity for viral clearance and cancer immune surveillance. Here, we report that glycolysis, which is inactivated during RLR activation, serves as a barrier to impede type I IFN production upon RLR activation. RLR-triggered MAVS-RIG-I recognition hijacks hexokinase binding to MAVS, leading to the impairment of hexokinase mitochondria localization and activation. Lactate serves as a key metabolite responsible for glycolysis-mediated RLR signaling inhibition by directly binding to MAVS transmembrane (TM) domain and preventing MAVS aggregation. Notably, lactate restoration reverses increased IFN production caused by lactate deficiency. Using pharmacological and genetic approaches, we show that lactate reduction by lactate dehydrogenase A (LDHA) inactivation heightens type I IFN production to protect mice from viral infection. Our study establishes a critical role of glycolysis-derived lactate in limiting RLR signaling and identifies MAVS as a direct sensor of lactate, which functions to connect energy metabolism and innate immunity.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Proteína 58 DEAD Box/antagonistas & inhibidores , Proteína 58 DEAD Box/metabolismo , Ácido Láctico/farmacología , Receptores de Superficie Celular/antagonistas & inhibidores , Receptores de Superficie Celular/metabolismo , Animales , Femenino , Glucólisis , Células HEK293 , Humanos , Interferón beta/metabolismo , L-Lactato Deshidrogenasa/genética , L-Lactato Deshidrogenasa/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Células RAW 264.7 , Receptores Inmunológicos , Transducción de Señal/efectos de los fármacos , TransfecciónRESUMEN
Porcine deltacoronavirus (PDCoV) is an emerging swine enteropathogenic coronavirus that causes watery diarrhea, vomiting and mortality in newborn piglets. Previous studies have suggested that PDCoV infection antagonizes RIG-I-like receptor (RLR)-mediated IFN-ß production to evade host innate immune defense, and PDCoV-encoded nonstructural protein nsp5 and accessory protein NS6 are associated with this process. However, whether the structural protein(s) of PDCoV also antagonize IFN-ß production remains unclear. In this study, we found that PDCoV nucleocapsid (N) protein, the most abundant viral structural protein, suppressed Sendai virus (SEV)-induced IFN-ß production and transcription factor IRF3 activation, but did not block IFN-ß production induced by overexpressing RIG-I/MDA5. Furthermore, study revealed that PDCoV N protein interacted with RIG-I and MDA5 in an in vitro overexpression system and evident interactions between N protein and RIG-I could be detected in the context of PDCoV infection, which interfered with the binding of dsRNA and protein activator of protein kinase R (PACT) to RIG-I. Together, our results demonstrate that PDCoV N protein is an IFN antagonist and utilizes diverse strategies to attenuate RIG-I recognition and activation.
Asunto(s)
Coronavirus/inmunología , Proteína 58 DEAD Box/antagonistas & inhibidores , Interferón beta/antagonistas & inhibidores , Proteínas de la Nucleocápside/inmunología , Porcinos/virología , Animales , Coronavirus/genética , Coronavirus/aislamiento & purificación , Infecciones por Coronavirus/veterinaria , Infecciones por Coronavirus/virología , Células HEK293 , Humanos , Factor 3 Regulador del Interferón/antagonistas & inhibidores , Interferón beta/genética , Unión Proteica , ARN Bicatenario/antagonistas & inhibidores , Proteínas de Unión al ARN/antagonistas & inhibidores , Receptores Inmunológicos , Virus Sendai/inmunología , Enfermedades de los Porcinos/virologíaRESUMEN
Patients infected with hepatitis C virus (HCV) have an increased risk of developing type 2 diabetes. HCV infection is linked to various liver abnormalities, potentially contributing to this association. We show that HCV infection increases the levels of hepatic selenoprotein P (SeP) mRNA (SEPP1 mRNA) and serum SeP, a hepatokine linked to insulin resistance. SEPP1 mRNA inhibits type I interferon responses by limiting the function of retinoic-acid-inducible gene I (RIG-I), a sensor of viral RNA. SEPP1 mRNA binds directly to RIG-I and inhibits its activity. SEPP1 mRNA knockdown in hepatocytes causes a robust induction of interferon-stimulated genes and decreases HCV replication. Clinically, high SeP serum levels are significantly associated with treatment failure of direct-acting antivirals in HCV-infected patients. Thus, SeP regulates insulin resistance and innate immunity, possibly inducing immune tolerance in the liver, and its upregulation may explain the increased risk of type 2 diabetes in HCV-infected patients.
Asunto(s)
Proteína 58 DEAD Box/antagonistas & inhibidores , Hepatitis C/patología , Interacciones Huésped-Patógeno , Evasión Inmune , ARN Mensajero/metabolismo , Selenoproteína P/biosíntesis , Humanos , Receptores InmunológicosRESUMEN
Influenza viruses can bring about acute respiratory diseases and are a potential hazard to human health. Antiviral drugs are the main ways to control the influenza virus infection except the vaccine. In this study, the immune regulation activity of pterodontic acid isolated from Laggera pterodonta induced by influenza A virus in vitro was evaluated. In studies on anti-influenza activity, our results showed that it maybe target the influenza protein of polymerase basic 1 (PB1), polymerase basic 2 (PB2), polymerase acid (PA), nuclear protein (NP), non-structural protein (NS), and matrix protein (M) but not hemagglutinin (HA) and neuraminidase (NA). In studies on immune regulation, our results demonstrated that pterodontic acid can inhibit the Retinoic acid inducible gene-I (RIG-I) expression in mRNA and protein level at 100 µg/ml, then further to clarify its action on the signalling pathway, The results indicated that pterodontic acid can inhibit the Tumor Necrosis Factor-related Apoptosis-inducing Ligand/Fas Ligand (TRAIL/Fasl) expression in mRNA level at 100 µg/ml; the cleaved caspase 3/7, p-NF-KB, and p-ERK were all suppressed in protein level by pterodontic acid at 100 µg/ml. This confirmed its mechanism that restrained the nuclear export of viral RNPs. The interferon system was also affected, the STAT1, IFN-α, IFN-ß expression were also inhibited by pterodontic acid at 25-100 µg/ml and also, the important programmed death-ligand of PD-L1 and PD-L2 was inhibited at 50-100 µg/ml. The mechanisms of pterodontic acid against influenza virus infection may be a cascade inhibition and it has the anti-inflammatory activity, which has no side effect, and can be as a supplement drug in clinical influenza virus infection.
Asunto(s)
Antivirales/farmacología , Asteraceae/química , Antígeno B7-H1/fisiología , Proteína 58 DEAD Box/antagonistas & inhibidores , Virus de la Influenza A/efectos de los fármacos , Interferón Tipo I/antagonistas & inhibidores , FN-kappa B/antagonistas & inhibidores , Proteína 2 Ligando de Muerte Celular Programada 1/antagonistas & inhibidores , Sesquiterpenos/farmacología , Células A549 , Antígeno B7-H1/antagonistas & inhibidores , Humanos , Virus de la Influenza A/fisiología , Proteína 2 Ligando de Muerte Celular Programada 1/fisiología , Receptores Inmunológicos , Ribonucleoproteínas/metabolismo , Factor de Transcripción STAT1/antagonistas & inhibidores , Transducción de Señal/efectos de los fármacos , Ligando Inductor de Apoptosis Relacionado con TNF/antagonistas & inhibidoresRESUMEN
Proteasome is a large protein complex, which degrades most intracellular proteins. It regulates numerous cellular processes, including the removal of misfolded or unfolded proteins, cell cycle control, and regulation of apoptosis. However, the function of proteasome subunits in viral immunity has not been well characterized. In this study, we identified PSMB1, a member of the proteasome ß subunits (PSMB) family, as a negative regulator of innate immune responses during viral infection. Knockdown of PSMB1 enhanced the RNA virus-induced cytokine and chemokine production. Overexpression of PSMB1 abolished virus-induced activation of the interferon-stimulated response element (ISRE) and interferon beta (IFNß) promoters. Mechanistically, PSMB1 inhibited the activation of RIG-I-like receptor (RLR) and Toll-like receptor 3 (TLR3) signaling pathways. PSMB1 was induced after viral infection and its interaction with IKK-ε promoted degradation of IKK-ε through the ubiquitin-proteasome system. Collectively, our study demonstrates PSMB1 is an important regulator of innate immune signaling.
Asunto(s)
Regulación de la Expresión Génica/inmunología , Quinasa I-kappa B/metabolismo , Inmunidad Innata , Complejo de la Endopetidasa Proteasomal/metabolismo , Virosis/inmunología , Línea Celular , Quimiocinas/inmunología , Citocinas/inmunología , Proteína 58 DEAD Box/antagonistas & inhibidores , Proteína 58 DEAD Box/genética , Técnicas de Silenciamiento del Gen , Humanos , Quinasa I-kappa B/genética , Interferón Tipo I/genética , Interferón beta/antagonistas & inhibidores , Complejo de la Endopetidasa Proteasomal/genética , Receptores Inmunológicos , Transducción de Señal/inmunología , Receptor Toll-Like 3/genética , Receptor Toll-Like 3/metabolismo , Replicación ViralRESUMEN
The RIG-I like receptors (RLRs) RIG-I and MDA5 are cytosolic RNA helicases best characterized as restriction factors for RNA viruses. However, evidence suggests RLRs participate in innate immune recognition of other pathogens, including DNA viruses. Kaposi's sarcoma-associated herpesvirus (KSHV) is a human gammaherpesvirus and the etiological agent of Kaposi's sarcoma and primary effusion lymphoma (PEL). Here, we demonstrate that RLRs restrict KSHV lytic reactivation and we demonstrate that restriction is facilitated by the recognition of host-derived RNAs. Misprocessed noncoding RNAs represent an abundant class of RIG-I substrates, and biochemical characterizations reveal that an infection-dependent reduction in the cellular triphosphatase DUSP11 results in an accumulation of select triphosphorylated noncoding RNAs, enabling their recognition by RIG-I. These findings reveal an intricate relationship between RNA processing and innate immunity, and demonstrate that an antiviral innate immune response can be elicited by the sensing of misprocessed cellular RNAs.