RESUMO
Increased receptor binding affinity may allow viruses to escape from Ab-mediated inhibition. However, how high-affinity receptor binding affects innate immune escape and T cell function is poorly understood. In this study, we used the lymphocytic choriomeningitis virus (LCMV) murine infection model system to create a mutated LCMV exhibiting higher affinity for the entry receptor α-dystroglycan (LCMV-GPH155Y). We show that high-affinity receptor binding results in increased viral entry, which is associated with type I IFN (IFN-I) resistance, whereas initial innate immune activation was not impaired during high-affinity virus infection in mice. Consequently, IFN-I resistance led to defective antiviral T cell immunity, reduced type II IFN, and prolonged viral replication in this murine model system. Taken together, we show that high-affinity receptor binding of viruses can trigger innate affinity escape including resistance to IFN-I resulting in prolonged viral replication.
Assuntos
Coriomeningite Linfocítica , Internalização do Vírus , Camundongos , Animais , Camundongos Knockout , Vírus da Coriomeningite Linfocítica/fisiologia , Replicação Viral , Camundongos Endogâmicos C57BL , Imunidade InataRESUMO
BACKGROUND: New therapies are urgently needed in melanoma, particularly in late-stage patients not responsive to immunotherapies and kinase inhibitors. To uncover novel potentiators of T cell anti-tumor immunity, we carried out an ex vivo pharmacological screen and identified 5-Nonyloxytryptamine (5-NL), a serotonin agonist, as increasing the ability of T cells to target tumor cells. METHODS: The pharmacological screen utilized lymphocytic choriomeningitis virus (LCMV)-primed splenic T cells and melanoma B16.F10 cells expressing the LCMV gp33 CTL epitope. In vivo tumor growth in C57BL/6 J and NSG mice, in vivo antibody depletion, flow cytometry, immunoblot, CRISPR/Cas9 knockout, histological and RNA-Seq analyses were used to decipher 5-NL's immunomodulatory effects in vitro and in vivo. RESULTS: 5-NL delayed tumor growth in vivo and the phenotype was dependent on the hosts' immune system, specifically CD8+ T cells. 5-NL's pro-immune effects were not directly consequential to T cells. Rather, 5-NL upregulated antigen presenting machinery in melanoma and other tumor cells in vitro and in vivo without increasing PD-L1 expression. Mechanistic studies indicated that 5-NL's induced MHC-I expression was inhibited by pharmacologically preventing cAMP Response Element-Binding Protein (CREB) phosphorylation. Importantly, 5-NL combined with anti-PD1 therapy showed significant improvement when compared to single anti-PD-1 treatment. CONCLUSIONS: This study demonstrates novel therapeutic opportunities for augmenting immune responses in poorly immunogenic tumors.
Assuntos
Linfócitos T CD8-Positivos , Melanoma , Camundongos , Animais , Regulação para Cima , Camundongos Endogâmicos C57BL , Vírus da Coriomeningite Linfocítica/genética , Melanoma/tratamento farmacológicoRESUMO
Pilocytic astrocytoma (PA), the most common pediatric brain tumor, is driven by aberrant mitogen-activated protein kinase signaling most commonly caused by BRAF gene fusions or activating mutations. While 5-year overall survival rates exceed 95%, tumor recurrence or progression constitutes a major clinical challenge in incompletely resected tumors. Here, we used similarity network fusion (SNF) analysis in an integrative multi-omics approach employing RNA transcriptomic and mass spectrometry-based proteomic profiling to molecularly characterize PA tissue samples from 62 patients. Thereby, we uncovered that PAs segregated into two molecularly distinct groups, namely, Group 1 and Group 2, which were validated in three non-overlapping cohorts. Patients with Group 1 tumors were significantly younger and showed worse progression-free survival compared to patients with group 2 tumors. Ingenuity pathways analysis (IPA) and gene set enrichment analysis (GSEA) revealed that Group 1 tumors were enriched for immune response pathways, such as interferon signaling, while Group 2 tumors showed enrichment for action potential and neurotransmitter signaling pathways. Analysis of immune cell-related gene signatures showed an enrichment of infiltrating T Cells in Group 1 versus Group 2 tumors. Taken together, integrative multi-omics of PA identified biologically distinct and prognostically relevant tumor groups that may improve risk stratification of this single pathway driven tumor type.
Assuntos
Astrocitoma , Neoplasias Encefálicas , Criança , Humanos , Multiômica , Proteômica , Astrocitoma/genética , Neoplasias Encefálicas/genética , Potenciais de AçãoRESUMO
Despite development of new antiviral drugs, viral infections are still a major health problem. The most potent antiviral defense mechanism is the innate production of type I interferon (IFN-I), which not only limits virus replication but also promotes antiviral T cell immunity through mechanisms, which remain insufficiently studied. Using the murine lymphocytic choriomeningitis virus model system, we show here that IFN-I signaling on T cells prevented their rapid elimination in vivo. Microarray analyses uncovered that IFN-I triggered the expression of selected inhibitory NK-cell-receptor ligands. Consequently, T cell immunity of IFN-I receptor (IFNAR)-deficient T cells could be restored by NK cell depletion or in NK-cell-deficient hosts (Nfil3(-/-)). The elimination of Ifnar1(-/-) T cells was dependent on NK-cell-mediated perforin expression. In summary, we identified IFN-I as a key player regulating the protection of T cells against regulatory NK cell function.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Citotoxicidade Imunológica , Interferon Tipo I/imunologia , Células Matadoras Naturais/imunologia , Coriomeningite Linfocítica/imunologia , Receptor de Interferon alfa e beta/imunologia , Animais , Fatores de Transcrição de Zíper de Leucina Básica/genética , Células Cultivadas , Imunidade Inata , Coriomeningite Linfocítica/virologia , Vírus da Coriomeningite Linfocítica/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Perforina/biossíntese , Receptor de Interferon alfa e beta/genética , Transdução de Sinais/imunologia , Replicação Viral/imunologiaRESUMO
The majority of childhood leukemias are precursor B-cell acute lymphoblastic leukemias (pB-ALLs) caused by a combination of prenatal genetic predispositions and oncogenic events occurring after birth. Although genetic predispositions are frequent in children (>1% to 5%), fewer than 1% of genetically predisposed carriers will develop pB-ALL. Although infectious stimuli are believed to play a major role in leukemogenesis, the critical determinants are not well defined. Here, by using murine models of pB-ALL, we show that microbiome disturbances incurred by antibiotic treatment early in life were sufficient to induce leukemia in genetically predisposed mice, even in the absence of infectious stimuli and independent of T cells. By using V4 and full-length 16S ribosomal RNA sequencing of a series of fecal samples, we found that genetic predisposition to pB-ALL (Pax5 heterozygosity or ETV6-RUNX1 fusion) shaped a distinct gut microbiome. Machine learning accurately (96.8%) predicted genetic predisposition using 40 of 3983 amplicon sequence variants as proxies for bacterial species. Transplantation of either wild-type (WT) or Pax5+/- hematopoietic bone marrow cells into WT recipient mice revealed that the microbiome is shaped and determined in a donor genotype-specific manner. Gas chromatography-mass spectrometry (GC-MS) analyses of sera from WT and Pax5+/- mice demonstrated the presence of a genotype-specific distinct metabolomic profile. Taken together, our data indicate that it is a lack of commensal microbiota rather than the presence of specific bacteria that promotes leukemia in genetically predisposed mice. Future large-scale longitudinal studies are required to determine whether targeted microbiome modification in children predisposed to pB-ALL could become a successful prevention strategy.
Assuntos
Suscetibilidade a Doenças , Disbiose/complicações , Fezes/microbiologia , Microbioma Gastrointestinal , Leucemia Experimental/prevenção & controle , Fator de Transcrição PAX5/fisiologia , Leucemia-Linfoma Linfoblástico de Células Precursoras B/prevenção & controle , Animais , Feminino , Leucemia Experimental/genética , Leucemia Experimental/microbiologia , Leucemia Experimental/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras B/microbiologia , Leucemia-Linfoma Linfoblástico de Células Precursoras B/patologiaRESUMO
OBJECTIVE: The Fragile X mental retardation (FMR) syndrome is a frequently inherited intellectual disability caused by decreased or absent expression of the FMR protein (FMRP). Lack of FMRP is associated with neuronal degradation and cognitive dysfunction but its role outside the central nervous system is insufficiently studied. Here, we identify a role of FMRP in liver disease. DESIGN: Mice lacking Fmr1 gene expression were used to study the role of FMRP during tumour necrosis factor (TNF)-induced liver damage in disease model systems. Liver damage and mechanistic studies were performed using real-time PCR, Western Blot, staining of tissue sections and clinical chemistry. RESULTS: Fmr1null mice exhibited increased liver damage during virus-mediated hepatitis following infection with the lymphocytic choriomeningitis virus. Exposure to TNF resulted in severe liver damage due to increased hepatocyte cell death. Consistently, we found increased caspase-8 and caspase-3 activation following TNF stimulation. Furthermore, we demonstrate FMRP to be critically important for regulating key molecules in TNF receptor 1 (TNFR1)-dependent apoptosis and necroptosis including CYLD, c-FLIPS and JNK, which contribute to prolonged RIPK1 expression. Accordingly, the RIPK1 inhibitor Necrostatin-1s could reduce liver cell death and alleviate liver damage in Fmr1null mice following TNF exposure. Consistently, FMRP-deficient mice developed increased pathology during acute cholestasis following bile duct ligation, which coincided with increased hepatic expression of RIPK1, RIPK3 and phosphorylation of MLKL. CONCLUSIONS: We show that FMRP plays a central role in the inhibition of TNF-mediated cell death during infection and liver disease.
Assuntos
Proteína do X Frágil da Deficiência Intelectual/fisiologia , Hepatite Viral Animal/imunologia , Fator de Necrose Tumoral alfa/imunologia , Animais , Infecções por Arenaviridae/imunologia , Infecções por Arenaviridae/patologia , Linfócitos T CD8-Positivos/imunologia , Morte Celular/efeitos dos fármacos , Morte Celular/imunologia , Morte Celular/fisiologia , Células Cultivadas , Colestase/imunologia , Colestase/metabolismo , Colestase/patologia , Proteína do X Frágil da Deficiência Intelectual/metabolismo , Hepatite Viral Animal/patologia , Hepatite Viral Animal/prevenção & controle , Hepatócitos/patologia , Imidazóis/farmacologia , Imidazóis/uso terapêutico , Indóis/farmacologia , Indóis/uso terapêutico , Vírus da Coriomeningite Linfocítica , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína Serina-Treonina Quinases de Interação com Receptores/antagonistas & inibidores , Proteína Serina-Treonina Quinases de Interação com Receptores/fisiologiaRESUMO
Glucose uptake into lymphocytes is accomplished by non-concentrative glucose carriers of the GLUT family (GLUT1, GLUT3, GLUT4, GLUT6) and/or by the Na+-coupled glucose carrier SGLT1. The latter accumulates glucose against glucose gradients and is still effective at very low extracellular glucose concentrations. Signaling involved in SGLT1 expression and activity includes protein kinase A (PKA), protein kinase C (PKC), serum- and glucocorticoid-inducible kinase (SGK1), AMP-activated kinase (AMPK), and Janus kinases (JAK2 and JAK3). Glucose taken up is partially stored as glycogen. In hypoxic environments, such as in tumors as well as infected and inflamed tissues, lymphocytes depend on energy production from glycogen-dependent glycolysis. The lack of SGLT1 may compromise glycogen storage and thus lymphocyte survival and function in hypoxic tissues. Accordingly, in mice, genetic knockout of sglt1 compromised bacterial clearance following Listeria monocytogenes infection leading to an invariably lethal course of the disease. Whether the effect was due to the lack of sglt1 in lymphocytes or in other cell types still remains to be determined. Clearly, additional experimental effort is required to define the role of glucose transport by GLUTs and particularly by SGLT1 for lymphocyte survival and function, as well as orchestration of the host defense against tumors and bacterial infections.
Assuntos
Proteínas Facilitadoras de Transporte de Glucose/metabolismo , Linfócitos/metabolismo , Proteínas de Transporte de Sódio-Glucose/metabolismo , Animais , Glucose/metabolismo , Proteínas Facilitadoras de Transporte de Glucose/genética , Humanos , Proteínas Quinases/metabolismo , Transdução de Sinais , Proteínas de Transporte de Sódio-Glucose/genéticaRESUMO
BACKGROUND & AIMS: Hepatic innate immune control of viral infections has largely been attributed to Kupffer cells, the liver-resident macrophages. However, hepatocytes, the parenchymal cells of the liver, also possess potent immunological functions in addition to their known metabolic functions. Owing to their abundance in the liver and known immunological functions, we aimed to investigate the direct antiviral mechanisms employed by hepatocytes. METHODS: Using lymphocytic choriomeningitis virus (LCMV) as a model of liver infection, we first assessed the role of myeloid cells by depletion prior to infection. We investigated the role of hepatocyte-intrinsic innate immune signaling by infecting mice lacking canonical NF-κB signaling (IkkßΔHep) specifically in hepatocytes. In addition, mice lacking hepatocyte-specific interferon-α/ß signaling-(IfnarΔHep), or interferon-α/ß signaling in myeloid cells-(IfnarΔMyel) were infected. RESULTS: Here, we demonstrate that LCMV activates NF-κB signaling in hepatocytes. LCMV-triggered NF-κB activation in hepatocytes did not depend on Kupffer cells or TNFR1 signaling but rather on Toll-like receptor signaling. LCMV-infected IkkßΔHep livers displayed strongly elevated viral titers due to LCMV accumulation within hepatocytes, reduced interferon-stimulated gene (ISG) expression, delayed intrahepatic immune cell influx and delayed intrahepatic LCMV-specific CD8+ T cell responses. Notably, viral clearance and ISG expression were also reduced in LCMV-infected primary hepatocytes lacking IKKß, demonstrating a hepatocyte-intrinsic effect. Similar to livers of IkkßΔHep mice, enhanced hepatocytic LCMV accumulation was observed in livers of IfnarΔHep mice, whereas IfnarΔMyel mice were able to control LCMV infection. Hepatocytic NF-κB signaling was also required for efficient ISG induction in HDV-infected dHepaRG cells and interferon-α/ß-mediated inhibition of HBV replication in vitro. CONCLUSIONS: Together, these data show that hepatocyte-intrinsic NF-κB is a vital amplifier of interferon-α/ß signaling, which is pivotal for strong early ISG responses, immune cell infiltration and hepatic viral clearance. LAY SUMMARY: Innate immune cells have been ascribed a primary role in controlling viral clearance upon hepatic infections. We identified a novel dual role for NF-κB signaling in infected hepatocytes which was crucial for maximizing interferon responses and initiating adaptive immunity, thereby efficiently controlling hepatic virus replication.
Assuntos
Hepacivirus/genética , Hepatite C Crônica/genética , Hepatite C Crônica/imunologia , Hepatócitos/imunologia , Coriomeningite Linfocítica/imunologia , Vírus da Coriomeningite Linfocítica/fisiologia , Subunidade p50 de NF-kappa B/genética , Polimorfismo de Nucleotídeo Único , Fator de Transcrição RelA/metabolismo , Replicação Viral/genética , Adulto , Animais , Células Cultivadas , Modelos Animais de Doenças , Feminino , Técnicas de Inativação de Genes , Genótipo , Hepatite C Crônica/virologia , Humanos , Quinase I-kappa B/deficiência , Quinase I-kappa B/genética , Coriomeningite Linfocítica/virologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Transdução de Sinais , Adulto JovemRESUMO
Innate immune activation is essential to mount an effective antiviral response and to prime adaptive immunity. Although a crucial role of CD169+ cells during vesicular stomatitis virus (VSV) infections is increasingly recognized, factors regulating CD169+ cells during viral infections remain unclear. Here, we show that tumor necrosis factor is produced by CD11b+ Ly6C+ Ly6G+ cells following infection with VSV. The absence of TNF or TNF receptor 1 (TNFR1) resulted in reduced numbers of CD169+ cells and in reduced type I interferon (IFN-I) production during VSV infection, with a severe disease outcome. Specifically, TNF triggered RelA translocation into the nuclei of CD169+ cells; this translocation was inhibited when the paracaspase MALT-1 was absent. Consequently, MALT1 deficiency resulted in reduced VSV replication, defective innate immune activation, and development of severe disease. These findings indicate that TNF mediates the maintenance of CD169+ cells and innate and adaptive immune activation during VSV infection.IMPORTANCE Over the last decade, strategically placed CD169+ metallophilic macrophages in the marginal zone of the murine spleen and lymph nodes (LN) have been shown to play a very important role in host defense against viral pathogens. CD169+ macrophages have been shown to activate innate and adaptive immunity via "enforced virus replication," a controlled amplification of virus particles. However, the factors regulating the CD169+ macrophages remain to be studied. In this paper, we show that after vesicular stomatitis virus infection, phagocytes produce tumor necrosis factor (TNF), which signals via TNFR1, and promote enforced virus replication in CD169+ macrophages. Consequently, lack of TNF or TNFR1 resulted in defective immune activation and VSV clearance.
Assuntos
Interferon Tipo I/imunologia , Macrófagos/imunologia , Fator de Necrose Tumoral alfa/imunologia , Estomatite Vesicular/imunologia , Imunidade Adaptativa , Animais , Imunidade Inata , Macrófagos/virologia , Camundongos , Camundongos Endogâmicos C57BL , Proteína de Translocação 1 do Linfoma de Tecido Linfoide Associado à Mucosa/genética , Receptores Tipo I de Fatores de Necrose Tumoral/imunologia , Lectina 1 Semelhante a Ig de Ligação ao Ácido Siálico , Fator de Transcrição RelA/metabolismo , Vesiculovirus/fisiologia , Replicação ViralRESUMO
The liver has an extraordinary capacity to regenerate through activation of key molecular pathways. However, central regulators controlling liver regeneration remain insufficiently studied. Here, we show that B cell-deficient animals failed to induce sufficient liver regeneration after partial hepatectomy (PHx). Consistently, adoptive transfer of B cells could rescue defective liver regeneration. B cell-mediated lymphotoxin beta production promoted recovery from PHx. Absence of B cells coincided with loss of splenic cluster of differentiation 169-positive (CD169+ ) macrophages. Moreover, depletion of CD169+ cells resulted in defective liver regeneration and decreased survival, which was associated with reduced hepatocyte proliferation. Mechanistically, CD169+ cells contributed to liver regeneration by inducing hepatic interleukin-6 (IL-6) production and signal transducer and activator of transcription 3 activation. Accordingly, treatment of CD169+ cell-depleted animals with IL-6/IL-6 receptor rescued liver regeneration and severe pathology following PHx. Conclusion: We identified CD169+ cells to be a central trigger for liver regeneration, by inducing key signaling pathways important for liver regeneration.
Assuntos
Linfócitos B/fisiologia , Regeneração Hepática/imunologia , Animais , Hepatectomia , Interleucina-6/metabolismo , Masculino , Camundongos , Lectina 1 Semelhante a Ig de Ligação ao Ácido Siálico/metabolismoRESUMO
Fibroblast growth factor 23 (FGF23) is released primarily from osteoblasts/osteocytes in bone. In cooperation with the transmembrane protein Klotho, FGF23 is a powerful inhibitor of 1α 25OH Vitamin D Hydroxylase (Cyp27b1) and thus of the formation of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). As 1,25(OH)2D3 up-regulates intestinal calcium and phosphate absorption, the downregulation of 1,25(OH)2D3 synthesis counteracts phosphate excess and tissue calcification. FGF23 also directly inhibits renal phosphate reabsorption. Other actions of FGF23 include triggering of cardiac hypertrophy. FGF23 formation and/or release are stimulated by 1,25(OH)2D3, phosphate excess, Ca2+, PTH, leptin, catecholamines, mineralocorticoids, volume depletion, lithium, high fat diet, iron deficiency, TNFα and TGFß2. The stimulating effect of 1,25(OH)2D3 on FGF23 expression is dependent on RAC1/PAK1 induced actin-polymerisation. Intracellular signaling involved in the stimulation of FGF23 release also includes increases in the cytosolic Ca2+ concentration ([Ca2+]i) following intracellular Ca2+ release and store-operated Ca2+ entry (SOCE). SOCE is accomplished by the Ca2+ release-activated calcium channel protein 1 (Orai1) and its stimulator stromal interaction molecule 1 (STIM1). Expression of Orai1, SOCE and FGF23-formation are up-regulated by the proinflammatory transcription factor NFκB. The present brief review describes the cellular mechanisms involved in FGF23 regulation and its sensitivity to both phosphate metabolism and inflammation. The case is made that up-regulation of FGF23 by inflammatory mediators and signaling may amplify inflammation by inhibiting formation of the anti-inflammatory 1,25(OH)2D3.
Assuntos
Fatores de Crescimento de Fibroblastos/metabolismo , Homeostase , Inflamação/etiologia , Fosfatos/metabolismo , Animais , Fator de Crescimento de Fibroblastos 23 , Humanos , Vitamina D/análogos & derivados , Vitamina D/antagonistas & inibidoresRESUMO
BACKGROUND: Cellular glucose uptake may involve either non-concentrative glucose carriers of the GLUT family or Na+-coupled glucose-carrier SGLT1, which accumulates glucose against glucose gradients and may thus accomplish cellular glucose uptake even at dramatically decreased extracellular glucose concentrations. SGLT1 is not only expressed in epithelia but as well in tumour cells and immune cells. Immune cell functions strongly depend on their metabolism, therefore we hypothesized that deficiency of SGLT1 modulates the defence against bacterial infection. To test this hypothesis, we infected wild type mice and gene targeted mice lacking functional SGLT1 with Listeria monocytogenes. METHODS: SGLT1 deficient mice and wild type littermates were infected with 1x104 CFU Listeria monocytogenes intravenously. Bacterial titers were determined by colony forming assay, SGLT1, TNF-α, IL-6 and IL-12a transcript levels were determined by qRT-PCR, as well as SGLT1 protein abundance and localization by immunohistochemistry. RESULTS: Genetic knockout of SGLT1 (Slc5a1-/- mice) significantly compromised bacterial clearance following Listeria monocytogenes infection with significantly enhanced bacterial load in liver, spleen, kidney and lung, and significantly augmented hepatic expression of TNF-α and IL-12a. While all wild type mice survived, all SGLT1 deficient mice died from the infection. CONCLUSIONS: SGLT1 is required for bacterial clearance and host survival following murine Listeria infection.
Assuntos
Expressão Gênica/imunologia , Glucose/imunologia , Listeriose/genética , Listeriose/mortalidade , Fígado/imunologia , Transportador 1 de Glucose-Sódio/imunologia , Animais , Carga Bacteriana , Transporte Biológico , Glucose/metabolismo , Interleucina-12/genética , Interleucina-12/imunologia , Interleucina-6/genética , Interleucina-6/imunologia , Rim/imunologia , Rim/microbiologia , Rim/patologia , Listeria monocytogenes , Listeriose/imunologia , Listeriose/microbiologia , Fígado/microbiologia , Fígado/patologia , Pulmão/imunologia , Pulmão/microbiologia , Pulmão/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , RNA Mensageiro/genética , RNA Mensageiro/imunologia , Transportador 1 de Glucose-Sódio/deficiência , Transportador 1 de Glucose-Sódio/genética , Baço/imunologia , Baço/microbiologia , Baço/patologia , Análise de Sobrevida , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/imunologiaRESUMO
BACKGROUND/AIMS: Viral infections represent a global health problem with the need for new viral therapies and better understanding of the immune response during infection. The most immediate and potent anti-viral defense mechanism is the production of type I interferon (IFN-I) which are activated rapidly following recognition of viral infection by host pathogen recognition receptors (PRR). The mechanisms of innate cellular signaling downstream of PRR activation remain to be fully understood. In the present study, we demonstrate that CASP2 and RIPK1 domain-containing adaptor with death domain (CRADD/RAIDD) is a critical component in type I IFN production. METHODS: The role of RAIDD during IFN-I production was investigated using western blot, shRNA mediated lentiviral knockdown, immunoprecipitation and IFN-I driven dual luciferase assay. RESULTS: Immunoprecipitation analysis revealed the molecular interaction of RAIDD with interferon regulatory factor 7 (IRF7) and its phosphorylating kinase IKKε. Using an IFN-4α driven dual luciferase analysis in RAIDD deficient cells, type I IFN activation by IKKε and IRF7 was dramatically reduced. Furthermore, deletion of either the caspase recruitment domain (CARD) or death domain (DD) of RAIDD inhibited IKKε and IRF7 mediated interferon-4α activation. CONCLUSION: We have identified that the adaptor molecule RAIDD coordinates IKKε and IRF7 interaction to ensure efficient expression of type I interferon.
Assuntos
Proteína Adaptadora de Sinalização CRADD/genética , Quinase I-kappa B/genética , Fator Regulador 7 de Interferon/genética , Receptor 3 Toll-Like/genética , Animais , Proteína Adaptadora de Sinalização CRADD/imunologia , Domínio de Ativação e Recrutamento de Caspases , Regulação da Expressão Gênica , Genes Reporter , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Células HEK293 , Humanos , Quinase I-kappa B/imunologia , Fator Regulador 7 de Interferon/imunologia , Interferon-alfa/genética , Interferon-alfa/imunologia , Interferon beta/genética , Interferon beta/imunologia , Lentivirus/genética , Lentivirus/metabolismo , Luciferases/genética , Luciferases/metabolismo , Camundongos , Plasmídeos/química , Plasmídeos/metabolismo , Poli I-C/farmacologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Transdução de Sinais , Receptor 3 Toll-Like/imunologiaRESUMO
UNLABELLED: The B cell-activating factor (BAFF) is critical for B cell development and humoral immunity in mice and humans. While the role of BAFF in B cells has been widely described, its role in innate immunity remains unknown. Using BAFF receptor (BAFFR)-deficient mice, we characterized BAFFR-related innate and adaptive immune functions following infection with vesicular stomatitis virus (VSV) and lymphocytic choriomeningitis virus (LCMV). We identified a critical role for BAFFR signaling in the generation and maintenance of the CD169(+) macrophage compartment. Consequently, Baffr(-) (/) (-) mice exhibited limited induction of innate type I interferon production after viral infection. Lack of BAFFR signaling reduced virus amplification and presentation following viral infection, resulting in highly reduced antiviral adaptive immune responses. As a consequence, BAFFR-deficient mice showed exacerbated and fatal disease after viral infection. Mechanistically, transient lack of B cells in Baffr(-) (/) (-) animals resulted in limited lymphotoxin expression, which is critical for maintenance of CD169(+) cells. In conclusion, BAFFR signaling affects both innate and adaptive immune activation during viral infections. IMPORTANCE: Viruses cause acute and chronic infections in humans resulting in millions of deaths every year. Innate immunity is critical for the outcome of a viral infection. Innate type I interferon production can limit viral replication, while adaptive immune priming by innate immune cells induces pathogen-specific immunity with long-term protection. Here, we show that BAFFR deficiency not only perturbed B cells, but also resulted in limited CD169(+) macrophages. These macrophages are critical in amplifying viral particles to trigger type I interferon production and initiate adaptive immune priming. Consequently, BAFFR deficiency resulted in reduced enforced viral replication, limited type I interferon production, and reduced adaptive immunity compared to BAFFR-competent controls. As a result, BAFFR-deficient mice were predisposed to fatal viral infections. Thus, BAFFR expression is critical for innate immune activation and antiviral immunity.
Assuntos
Infecções por Arenaviridae/imunologia , Macrófagos/química , Macrófagos/imunologia , Receptores de Interleucina-4/deficiência , Infecções por Rhabdoviridae/imunologia , Lectina 1 Semelhante a Ig de Ligação ao Ácido Siálico/análise , Imunidade Adaptativa , Animais , Imunidade Inata , Interferon Tipo I/metabolismo , Vírus da Coriomeningite Linfocítica/imunologia , Camundongos Knockout , Transdução de Sinais , Vesiculovirus/imunologiaRESUMO
UNLABELLED: Hepatic failure is commonly associated with anemia, which may result from gastrointestinal bleeding, vitamin deficiency, or liver-damaging diseases, such as infection and alcohol intoxication. At least in theory, anemia during hepatic failure may result from accelerated clearance of circulating erythrocytes. Here we show that bile duct ligation (BDL) in mice leads to severe anemia despite increased reticulocyte numbers. Bilirubin stimulated suicidal death of human erythrocytes. Mechanistically, bilirubin triggered rapid Ca(2+) influx, sphingomyelinase activation, formation of ceramide, and subsequent translocation of phosphatidylserine to the erythrocyte surface. Consistent with our in vitro and in vivo findings, incubation of erythrocytes in serum from patients with liver disease induced suicidal death of erythrocytes in relation to their plasma bilirubin concentration. Consistently, patients with hyperbilirubinemia had significantly lower erythrocyte and significantly higher reticulocyte counts compared to patients with low bilirubin levels. CONCLUSION: Bilirubin triggers suicidal erythrocyte death, thus contributing to anemia during liver disease.
Assuntos
Anemia/etiologia , Bilirrubina/sangue , Eritrócitos/fisiologia , Falência Hepática/complicações , Idoso , Animais , Cálcio/metabolismo , Estudos de Casos e Controles , Morte Celular , Feminino , Voluntários Saudáveis , Humanos , Falência Hepática/sangue , Masculino , Camundongos , Pessoa de Meia-Idade , Esfingomielina Fosfodiesterase/metabolismoRESUMO
Rapid activation of immune responses is necessary for antibacterial defense, but excessive immune activation can result in life-threatening septic shock. Understanding how these processes are balanced may provide novel therapeutic potential in treating inflammatory disease. Fc receptors are crucial for innate immune activation. However, the role of the putative Fc receptor for IgM, known as Toso/Faim3, has to this point been unclear. In this study, we generated Toso-deficient mice and used them to uncover a critical regulatory function of Toso in innate immune activation. Development of innate immune cells was intact in the absence of Toso, but Toso-deficient neutrophils exhibited more reactive oxygen species production and reduced phagocytosis of pathogens compared with controls. Cytokine production was also decreased in Toso(-/-) mice compared with WT animals, rendering them resistant to septic shock induced by lipopolysaccharide. However, Toso(-/-) mice also displayed limited cytokine production after infection with the bacterium Listeria monocytogenes that was correlated with elevated presence of Listeria throughout the body. Accordingly, Toso(-/-) mice succumbed to infections of L. monocytogenes, whereas WT mice successfully eliminated the infection. Taken together, our data reveal Toso to be a unique regulator of innate immune responses during bacterial infection and septic shock.
Assuntos
Proteínas de Transporte/imunologia , Granulócitos/imunologia , Imunidade Inata/imunologia , Listeriose/imunologia , Ativação de Macrófagos/imunologia , Proteínas de Membrana/imunologia , Monócitos/imunologia , Análise de Variância , Animais , Proteínas de Transporte/genética , Cruzamentos Genéticos , Citocinas/metabolismo , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Immunoblotting , Proteínas de Membrana/genética , Camundongos , Camundongos Knockout , Peroxidase/metabolismo , Fagocitose/imunologia , Espécies Reativas de Oxigênio/metabolismo , Reação em Cadeia da Polimerase em Tempo RealRESUMO
Central nervous system (CNS) involvement remains a clinical hurdle in treating childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL). The disease mechanisms of CNS leukemia are primarily investigated using 2D cell culture and mouse models. Given the variations in cellular identity and architecture between the human and murine CNS, it becomes imperative to seek complementary models to study CNS leukemia. Here, we present a first-of-its-kind 3D co-culture model combining human brain organoids and BCP-ALL-cells. We noticed significantly higher engraftment of BCP-ALL cell lines and patient-derived xenograft (PDX) cells in cerebral organoids as compared to non-ALL-cells. To validate translatability between organoid co-culture and in vivo murine models, we confirmed that targeting CNS leukemia relevant pathways like CD79a/Igα or CXCR4-SDF1 reduced the invasion of BCP-ALL-cells into organoids. RNA sequencing and functional validations of organoid-invading leukemia cells compared to the non-invaded fraction revealed significant upregulation of AP-1 transcription factor-complex members in organoid-invading cells. Moreover, we detected a significant enrichment of AP-1 pathway genes in ALL-PDX-cells recovered from the CNS compared to spleen blasts of mice transplanted with TCF3::PBX1+ PDX-cells, substantiating the role of AP-1 signaling in CNS disease. Accordingly, we found significantly higher levels of the AP-1-gene JUN in patients initially diagnosed as CNS-positive compared to CNS-negative cases as well as CNS-relapse vs non-CNS-relapse cases in a cohort of 100 BCP-ALL-patients. Our results suggest CNS-organoids as a novel model to investigate CNS-involvement and identify the AP-1 pathway as a critical driver of CNS-disease in BCP-ALL.
RESUMO
Viral-based cancer therapies have tremendous potential, especially in the context of treating poorly infiltrated cold tumors. However, in tumors with intact anti-viral interferon (IFN) pathways, while some oncolytic viruses induce strong innate and adaptive immune responses, they are neutralized before exerting their therapeutic effect. Arenaviruses, particularly the lymphocytic choriomeningitis virus (LCMV) is a noncytopathic virus with preferential cancer tropism and evolutionary mechanisms to escape the immune system for longer and to block early clearance. These escape mechanisms include inhibition of the MAVS dependent IFN pathway and spike protein antigen masking. Regarding its potential for cancer treatment, LCMV is therefore able to elicit long-term responses within the tumor microenvironment (TME), boost anti-tumor immune responses and polarize poorly infiltrating tumors towards a hot phenotype. Other arenaviruses including the attenuated Junin virus vaccine also have anti-tumor effects. Furthermore, the LCMV and Pichinde arenaviruses are currently being used to create vector-based vaccines with attenuated but replicating virus. This review focuses on highlighting the potential of arenaviruses as anti-cancer therapies. This includes providing a molecular understanding of its tropism as well as highlighting past and present preclinical and clinical applications of noncytophatic arenavirus therapies and their potential in bridging the gap in the treatment of cancers weakly responsive or unresponsive to oncolytic viruses. In summary, arenaviruses represent promising new therapies to broaden the arsenal of anti-tumor therapies for generating an immunogenic tumor microenvironment.