RESUMEN
In plants, pathogen effector-triggered immunity (ETI) often leads to programmed cell death, which is restricted by NPR1, an activator of systemic acquired resistance. However, the biochemical activities of NPR1 enabling it to promote defense and restrict cell death remain unclear. Here we show that NPR1 promotes cell survival by targeting substrates for ubiquitination and degradation through formation of salicylic acid-induced NPR1 condensates (SINCs). SINCs are enriched with stress response proteins, including nucleotide-binding leucine-rich repeat immune receptors, oxidative and DNA damage response proteins, and protein quality control machineries. Transition of NPR1 into condensates is required for formation of the NPR1-Cullin 3 E3 ligase complex to ubiquitinate SINC-localized substrates, such as EDS1 and specific WRKY transcription factors, and promote cell survival during ETI. Our analysis of SINCs suggests that NPR1 is centrally integrated into the cell death or survival decisions in plant immunity by modulating multiple stress-responsive processes in this quasi-organelle.
Asunto(s)
Proteínas de Arabidopsis/inmunología , Proteínas de Arabidopsis/metabolismo , Supervivencia Celular/inmunología , Inmunidad de la Planta/inmunología , Arabidopsis/inmunología , Arabidopsis/metabolismo , Regulación de la Expresión Génica de las Plantas/inmunología , Ácido Salicílico/inmunología , Ácido Salicílico/metabolismo , Ubiquitinación/inmunologíaRESUMEN
Alterations in the cGAS-STING DNA-sensing pathway affect intestinal homeostasis. We sought to delineate the functional role of STING in intestinal inflammation. Increased STING expression was a feature of intestinal inflammation in mice with colitis and in humans afflicted with inflammatory bowel disease. Mice bearing an allele rendering STING constitutively active exhibited spontaneous colitis and dysbiosis, as well as progressive chronic intestinal inflammation and fibrosis. Bone marrow chimera experiments revealed STING accumulation in intestinal macrophages and monocytes as the initial driver of inflammation. Depletion of Gram-negative bacteria prevented STING accumulation in these cells and alleviated intestinal inflammation. STING accumulation occurred at the protein rather than transcript level, suggesting post-translational stabilization. We found that STING was ubiquitinated in myeloid cells, and this K63-linked ubiquitination could be elicited by bacterial products, including cyclic di-GMP. Our findings suggest a positive feedback loop wherein dysbiosis foments the accumulation of STING in intestinal myeloid cells, driving intestinal inflammation.
Asunto(s)
Colitis/inmunología , Disbiosis/inmunología , Inmunidad Innata/inmunología , Proteínas de la Membrana/inmunología , Células Mieloides/inmunología , Ubiquitinación/inmunología , Animales , Estudios de Casos y Controles , Femenino , Humanos , Inflamación/inmunología , Intestinos/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Monocitos/inmunologíaRESUMEN
Autoinflammatory diseases were first recognized nearly 20 years ago as distinct clinical and immunological entities caused by dysregulation in the innate immune system. Since then, advances in genomic techniques have led to the identification of new monogenic disorders and their corresponding signaling pathways. Here we review these monogenic autoinflammatory diseases, ranging from periodic fever syndromes caused by dysregulated inflammasome-mediated production of the cytokine IL-1ß to disorders arising from perturbations in signaling by the transcription factor NF-κB, ubiquitination, cytokine signaling, protein folding, type I interferon production and complement activation, and we further examine their molecular mechanisms. We also explore the overlap among autoinflammation, autoimmunity and immunodeficiency, and pose a series of unanswered questions that are expected to be central in autoinflammatory disease research in the coming decade.
Asunto(s)
Autoinmunidad/inmunología , Enfermedades Autoinflamatorias Hereditarias/inmunología , Inmunidad Innata/inmunología , Síndromes de Inmunodeficiencia/inmunología , Inflamasomas/inmunología , Inflamación/inmunología , Activación de Complemento/inmunología , Citocinas/inmunología , Enfermedades Autoinflamatorias Hereditarias/genética , Humanos , Interferón Tipo I/inmunología , Interleucina-1beta/inmunología , FN-kappa B/inmunología , Pliegue de Proteína , Transducción de Señal , Ubiquitinación/inmunologíaRESUMEN
Sepsis is a bi-phasic inflammatory disease that threatens approximately 30 million lives and claims over 14 million annually, yet little is known regarding the molecular switches and pathways that regulate this disease. Here, we have described ABCF1, an ATP-Binding Cassette (ABC) family member protein, which possesses an E2 ubiquitin enzyme activity, through which it controls the Lipopolysaccharide (LPS)- Toll-like Receptor-4 (TLR4) mediated gram-negative insult by targeting key proteins for K63-polyubiquitination. Ubiquitination by ABCF1 shifts the inflammatory profile from an early phase MyD88-dependent to a late phase TRIF-dependent signaling pathway, thereby regulating TLR4 endocytosis and modulating macrophage polarization from M1 to M2 phase. Physiologically, ABCF1 regulates the shift from the inflammatory phase of sepsis to the endotoxin tolerance phase, and modulates cytokine storm and interferon-ß (IFN-ß)-dependent production by the immunotherapeutic mediator, SIRT1. Consequently, ABCF1 controls sepsis induced mortality by repressing hypotension-induced renal circulatory dysfunction.
Asunto(s)
Transportadoras de Casetes de Unión a ATP/inmunología , Macrófagos/inmunología , Sepsis/inmunología , Choque Séptico/inmunología , Enzimas Ubiquitina-Conjugadoras/inmunología , Transportadoras de Casetes de Unión a ATP/genética , Transportadoras de Casetes de Unión a ATP/metabolismo , Adenosina Trifosfato/inmunología , Adenosina Trifosfato/metabolismo , Animales , Citocinas/inmunología , Citocinas/metabolismo , Femenino , Interferón beta/inmunología , Interferón beta/metabolismo , Lipopolisacáridos/administración & dosificación , Lipopolisacáridos/inmunología , Activación de Macrófagos/efectos de los fármacos , Activación de Macrófagos/genética , Activación de Macrófagos/inmunología , Macrófagos/clasificación , Macrófagos/metabolismo , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Interferencia de ARN , Sepsis/genética , Sepsis/metabolismo , Choque Séptico/genética , Choque Séptico/metabolismo , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , Transducción de Señal/inmunología , Receptor Toll-Like 4/inmunología , Receptor Toll-Like 4/metabolismo , Enzimas Ubiquitina-Conjugadoras/genética , Enzimas Ubiquitina-Conjugadoras/metabolismo , Ubiquitinación/inmunologíaRESUMEN
The key molecular mechanisms that control signaling via T cell antigen receptors (TCRs) remain to be fully elucidated. Here we found that Nrdp1, a ring finger-type E3 ligase, mediated Lys33 (K33)-linked polyubiquitination of the signaling kinase Zap70 and promoted the dephosphorylation of Zap70 by the acidic phosphatase-like proteins Sts1 and Sts2 and thereby terminated early TCR signaling in CD8(+) T cells. Nrdp1 deficiency significantly promoted the activation of naive CD8(+) T cells but not that of naive CD4(+) T cells after engagement of the TCR. Nrdp1 interacted with Zap70 and with Sts1 and Sts2 and connected K33 linkage of Zap70 to Sts1- and Sts2-mediated dephosphorylation. Our study suggests that Nrdp1 terminates early TCR signaling by inactivating Zap70 and provides new mechanistic insights into the non-proteolytic regulation of TCR signaling by E3 ligases.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Proteínas Portadoras/inmunología , Activación de Linfocitos/inmunología , Lisina/inmunología , Proteína Tirosina Quinasa ZAP-70/inmunología , Animales , Linfocitos T CD8-positivos/metabolismo , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Activación de Linfocitos/genética , Lisina/genética , Lisina/metabolismo , Ratones Congénicos , Ratones Endogámicos C57BL , Ratones Noqueados , Microscopía Confocal , Fosforilación/inmunología , Poliubiquitina/inmunología , Poliubiquitina/metabolismo , Unión Proteica/inmunología , Interferencia de ARN , Receptores de Antígenos de Linfocitos T/genética , Receptores de Antígenos de Linfocitos T/inmunología , Receptores de Antígenos de Linfocitos T/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción de Señal/genética , Transducción de Señal/inmunología , Transcriptoma/genética , Transcriptoma/inmunología , Ubiquitina-Proteína Ligasas , Ubiquitinación/inmunología , Proteína Tirosina Quinasa ZAP-70/metabolismoRESUMEN
Deubiquitinases (DUBs) are a new class of drug targets, although the physiological function of only few DUBs has been characterized. Here we identified the DUB USP15 as a crucial negative regulator of T cell activation. USP15 stabilized the E3 ubiquitin ligase MDM2, which in turn negatively regulated T cell activation by targeting the degradation of the transcription factor NFATc2. USP15 deficiency promoted T cell activation in vitro and enhanced T cell responses to bacterial infection and tumor challenge in vivo. USP15 also stabilized MDM2 in cancer cells and regulated p53 function and cancer-cell survival. Our results suggest that inhibition of USP15 may both induce tumor cell apoptosis and boost antitumor T cell responses.
Asunto(s)
Factores de Transcripción NFATC/metabolismo , Proteínas Proto-Oncogénicas c-mdm2/inmunología , Células TH1/inmunología , Proteasas Ubiquitina-Específicas/inmunología , Traslado Adoptivo , Animales , Apoptosis/inmunología , Diferenciación Celular/inmunología , Línea Celular Tumoral , Supervivencia Celular , Células HCT116 , Humanos , Leupeptinas/farmacología , Listeria monocytogenes/inmunología , Listeriosis/inmunología , Activación de Linfocitos/inmunología , Melanoma Experimental/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Proteínas Proto-Oncogénicas c-mdm2/genética , Escape del Tumor , Proteína p53 Supresora de Tumor/inmunología , Proteasas Ubiquitina-Específicas/genética , Ubiquitinación/genética , Ubiquitinación/inmunologíaRESUMEN
The E3 ligase ARIH2 has an unusual structure and mechanism of elongating ubiquitin chains. To understand its physiological role, we generated gene-targeted mice deficient in ARIH2. ARIH2 deficiency resulted in the embryonic death of C57BL/6 mice. On a mixed genetic background, the lethality was attenuated, with some mice surviving beyond weaning and then succumbing to an aggressive multiorgan inflammatory response. We found that in dendritic cells (DCs), ARIH2 caused degradation of the inhibitor IκBß in the nucleus, which abrogated its ability to sequester, protect and transcriptionally coactivate the transcription factor subunit p65 in the nucleus. Loss of ARIH2 caused dysregulated activation of the transcription factor NF-κB in DCs, which led to lethal activation of the immune system in ARIH2-sufficent mice reconstituted with ARIH2-deficient hematopoietic stem cells. Our data have therapeutic implications for targeting ARIH2 function.
Asunto(s)
Células Dendríticas/inmunología , Desarrollo Embrionario/inmunología , Insuficiencia Multiorgánica/inmunología , Ubiquitina-Proteína Ligasas/fisiología , Animales , Células Cultivadas , Modelos Animales de Enfermedad , Desarrollo Embrionario/genética , Hematopoyesis/genética , Humanos , Sistema Inmunológico/fisiología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Terapia Molecular Dirigida , Insuficiencia Multiorgánica/genética , FN-kappa B/metabolismo , Activación Transcripcional/inmunología , Ubiquitina-Proteína Ligasas/genética , Ubiquitinación/genética , Ubiquitinación/inmunologíaRESUMEN
The mammalian immune system has the ability to discriminate between pathogenic microbes and nonpathogenic microbes to control inflammation. Here we investigated the ubiquitination profiles of host proteins after infection of macrophages with a virulent strain of the intracellular bacterium Legionella pneumophila or a nonpathogenic mutant of L. pneumophila. Only infection with pathogenic L. pneumophila resulted in ubiquitination of positive regulators of the metabolic checkpoint kinase mTOR and led to diminished mTOR activity. Detection of pathogen signatures resulted in translational biasing toward proinflammatory cytokines through mTOR-mediated regulation of cap-dependent translation. Thus, there is a pathogen-detection program in macrophages that stimulates protein ubiquitination and the degradation of regulators of mTOR, which suppresses mTOR function and directs a proinflammatory cytokine program.
Asunto(s)
Legionella pneumophila/inmunología , Macrófagos/inmunología , Transducción de Señal/inmunología , Serina-Treonina Quinasas TOR/inmunología , Ubiquitinación/inmunología , Animales , Secuencia de Bases , Línea Celular , Células Cultivadas , Citocinas/genética , Citocinas/inmunología , Citocinas/metabolismo , Factor 4E Eucariótico de Iniciación/genética , Factor 4E Eucariótico de Iniciación/inmunología , Factor 4E Eucariótico de Iniciación/metabolismo , Expresión Génica/inmunología , Interacciones Huésped-Patógeno/inmunología , Immunoblotting , Legionella pneumophila/genética , Enfermedad de los Legionarios/inmunología , Enfermedad de los Legionarios/metabolismo , Enfermedad de los Legionarios/microbiología , Macrófagos/metabolismo , Macrófagos/microbiología , Ratones , Datos de Secuencia Molecular , Mutación/inmunología , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/inmunología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Interferencia de ARN/inmunología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Serina-Treonina Quinasas TOR/genética , Serina-Treonina Quinasas TOR/metabolismoRESUMEN
During viral infection, sensing of cytosolic DNA by the cyclic GMP-AMP synthase (cGAS) activates the adaptor protein STING and triggers an antiviral response. Little is known about the mechanisms that determine the kinetics of activation and deactivation of the cGAS-STING pathway, ensuring effective but controlled innate antiviral responses. Here we found that the ubiquitin ligase Trim38 targets cGas for sumoylation in uninfected cells and during the early phase of viral infection. Sumoylation of cGas prevented its polyubiquitination and degradation. Trim38 also sumoylated Sting during the early phase of viral infection, promoting both Sting activation and protein stability. In the late phase of infection, cGas and Sting were desumoylated by Senp2 and subsequently degraded via proteasomal and chaperone-mediated autophagy pathways, respectively. Our findings reveal an essential role for Trim38 in the innate immune response to DNA virus and provide insight into the mechanisms that ensure optimal activation and deactivation of the cGAS-STING pathway.
Asunto(s)
Virus ADN/inmunología , ADN/metabolismo , Nucleótidos Cíclicos/metabolismo , Nucleotidiltransferasas/metabolismo , Sumoilación/fisiología , Virosis/metabolismo , Animales , Proteínas Portadoras/metabolismo , Cisteína Endopeptidasas/metabolismo , Inmunidad Innata/inmunología , Cinética , Proteínas de la Membrana/metabolismo , Ratones , Complejo de la Endopetidasa Proteasomal/metabolismo , Transducción de Señal/inmunología , Transducción de Señal/fisiología , Sumoilación/inmunología , Proteínas de Motivos Tripartitos , Ubiquitina-Proteína Ligasas , Ubiquitinación/inmunología , Ubiquitinación/fisiologíaRESUMEN
The ST2L receptor for interleukin 33 (IL-33) mediates pulmonary inflammation and immune system-related disorders, such as asthma and rheumatoid arthritis. At present, very little is known about the molecular regulation of ST2L expression. Here we found that FBXL19, an 'orphan' member of the Skp1-Cullin-F-box family of E3 ubiquitin ligases, selectively bound to ST2L to mediate its polyubiquitination and elimination in the proteasome. Degradation of ST2L involved phosphorylation of ST2L at Ser442 catalyzed by the kinase GSK3ß. Overexpression of FBXL19 abrogated the proapoptotic and inflammatory effects of IL-33 and lessened the severity of lung injury in mouse models of pneumonia. Our results suggest that modulation of the IL-33-ST2L axis by ubiquitin ligases might serve as a unique strategy for lessening pulmonary inflammation.
Asunto(s)
Proteínas de Unión al ADN/inmunología , Proteínas F-Box/inmunología , Neumonía/inmunología , Receptores de Interleucina/inmunología , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitinación/inmunología , Animales , Células Cultivadas , Proteínas de Unión al ADN/metabolismo , Proteínas F-Box/metabolismo , Glucógeno Sintasa Quinasa 3/metabolismo , Glucógeno Sintasa Quinasa 3 beta , Proteína 1 Similar al Receptor de Interleucina-1 , Ratones , Ratones Endogámicos C57BL , Fosforilación , Neumonía/patología , Complejo de la Endopetidasa Proteasomal/metabolismo , Serina/metabolismo , Índice de Severidad de la EnfermedadRESUMEN
Over the last two decades the mechanisms that underpin cell survival and cell death have been intensively studied. One molecule in particular, Receptor Interacting Protein Kinase 1 (RIPK1), has gained interest due to the ability to function upstream of both NF-κB signaling and caspase-dependent and -independent cell death. RIPK1 is critical in determining cell fate downstream of cytokine signaling receptors such as the Tumour Necrosis Factor Receptor Super Family (TNFRSF) and the innate immune Toll-like receptors. Various studies have attempted to untangle how ubiquitination of RIPK1 dictates signaling outcomes; however, due to the complex nature of ubiquitin signaling it has been difficult to prove that ubiquitination of RIPK1 does in fact influence signaling outcomes. Therefore, we ask the question: What do we really know about RIPK1 ubiquitination, and, to what extent can we conclude that ubiquitination of RIPK1 impacts RIPK1-mediated signaling events?
Asunto(s)
Proteína Serina-Treonina Quinasas de Interacción con Receptores/metabolismo , Ubiquitinación/inmunología , HumanosRESUMEN
The orphan nuclear receptor SHP (small heterodimer partner) is a transcriptional corepressor that regulates hepatic metabolic pathways. Here we identified a role for SHP as an intrinsic negative regulator of Toll-like receptor (TLR)-triggered inflammatory responses. SHP-deficient mice were more susceptible to endotoxin-induced sepsis. SHP had dual regulatory functions in a canonical transcription factor NF-κB signaling pathway, acting as both a repressor of transactivation of the NF-κB subunit p65 and an inhibitor of polyubiquitination of the adaptor TRAF6. SHP-mediated inhibition of signaling via the TLR was mimicked by macrophage-stimulating protein (MSP), a strong inducer of SHP expression, via an AMP-activated protein kinase-dependent signaling pathway. Our data identify a previously unrecognized role for SHP in the regulation of TLR signaling.
Asunto(s)
FN-kappa B/inmunología , Receptores Citoplasmáticos y Nucleares/inmunología , Sepsis/inmunología , Receptores Toll-Like/inmunología , Proteínas Quinasas Activadas por AMP/inmunología , Animales , Inmunoprecipitación de Cromatina , Femenino , Immunoblotting , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Transducción de Señal , Factor 6 Asociado a Receptor de TNF/inmunología , Ubiquitinación/inmunologíaRESUMEN
The antiviral innate immune responses are crucial steps during host defense and must be strictly regulated, but the molecular mechanisms of control remain unclear. In this study, we report increased expression of human ATPase Na+/K+ transporting subunit ß 1(ATP1B1) after DNA and RNA virus infections. We found that the expression of ATP1B1 can inhibit viral replication and increase the levels of IFNs, IFN-stimulated genes, and inflammatory cytokines. Knockdown of ATP1B1 by specific short hairpin RNA had the opposite effects. Upon viral infection, ATP1B1 was induced, interacted with TRAF3 and TRAF6, and potentiated the ubiquitination of these proteins, leading to increased phosphorylation of downstream molecules, including TGF-ß-activated kinase 1 (TAK1) and TANK-binding kinase 1 (TBK1). These results reveal a previously unrecognized role of ATP1B1 in antiviral innate immunity and suggest a novel mechanism for the induction of IFNs and proinflammatory cytokines during viral infection.
Asunto(s)
Inmunidad Innata/inmunología , Péptidos y Proteínas de Señalización Intracelular/inmunología , ATPasa Intercambiadora de Sodio-Potasio/inmunología , Factor 3 Asociado a Receptor de TNF/inmunología , Regulación hacia Arriba/inmunología , Animales , Células Cultivadas , Chlorocebus aethiops , Infecciones por Virus ADN/inmunología , Virus ADN/inmunología , Humanos , Infecciones por Virus ARN/inmunología , Virus ARN/inmunología , ATPasa Intercambiadora de Sodio-Potasio/genética , Ubiquitinación/inmunología , Replicación ViralRESUMEN
Helicobacter pylori is the major etiological agent for most gastric cancer. CagA has been reported to be an important virulence factor of H. pylori, but its effect on the immune response is not yet clear. In this study, wild-type C57BL/6 mice and Ptpn6me-v/me-v mice were randomly assigned for infection with H. pylori We demonstrated that CagA suppressed H. pylori-stimulated expression of proinflammatory cytokines in vivo. Besides, we infected mouse peritoneal macrophages RAW264.7 and AGS with H. pylori Our results showed that CagA suppressed expression of proinflammatory cytokines through inhibiting the MAPKs and NF-κB pathways activation in vitro. Mechanistically, we found that CagA interacted with the host cellular tyrosine phosphatase SHP-1, which facilitated the recruitment of SHP-1 to TRAF6 and inhibited the K63-linked ubiquitination of TRAF6, which obstructed the transmission of signal downstream. Taken together, these findings reveal a previously unknown mechanism by which CagA negatively regulates the posttranslational modification of TRAF6 in innate antibacterial immune response and provide molecular basis for new therapeutics to treat microbial infection.
Asunto(s)
Antígenos Bacterianos/metabolismo , Proteínas Bacterianas/metabolismo , Infecciones por Helicobacter/inmunología , Helicobacter pylori/inmunología , Proteína Tirosina Fosfatasa no Receptora Tipo 6/metabolismo , Factor 6 Asociado a Receptor de TNF/metabolismo , Animales , Antígenos Bacterianos/genética , Proteínas Bacterianas/genética , Modelos Animales de Enfermedad , Mucosa Gástrica/inmunología , Mucosa Gástrica/microbiología , Mucosa Gástrica/patología , Células HEK293 , Células HeLa , Infecciones por Helicobacter/microbiología , Infecciones por Helicobacter/patología , Helicobacter pylori/metabolismo , Humanos , Inmunidad Innata , Lisina/metabolismo , Macrófagos Peritoneales , Masculino , Ratones , Ratones Transgénicos , Cultivo Primario de Células , Proteína Tirosina Fosfatasa no Receptora Tipo 6/genética , Células RAW 264.7 , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Transducción de Señal/inmunología , Transfección , Ubiquitinación/inmunologíaRESUMEN
Trafficking of toll-like receptor 3 (TLR3) from the endoplasmic reticulum (ER) to endolysosomes and its subsequent proteolytic cleavage are required for it to sense viral double-stranded RNA (dsRNA) and trigger antiviral response, yet the underlying mechanisms remain enigmatic. We show that the E3 ubiquitin ligase TRIM3 is mainly located in the Golgi apparatus and transported to the early endosomes upon stimulation with the dsRNA analog poly(I:C). TRIM3 mediates K63-linked polyubiquitination of TLR3 at K831, which is enhanced following poly(I:C) stimulation. The polyubiquitinated TLR3 is recognized and sorted by the ESCRT (endosomal sorting complex required for transport) complexes to endolysosomes. Deficiency of TRIM3 impairs TLR3 trafficking from the Golgi apparatus to endosomes and its subsequent activation. Trim3-/- cells and mice express lower levels of antiviral genes and show lower levels of inflammatory response following poly(I:C) but not lipopolysaccharide (LPS) stimulation. These findings suggest that TRIM3-mediated polyubiquitination of TLR3 represents a feedback-positive regulatory mechanism for TLR3-mediated innate immune and inflammatory responses.
Asunto(s)
Proteínas Portadoras/inmunología , Complejos de Clasificación Endosomal Requeridos para el Transporte/inmunología , Inmunidad Innata/inmunología , Receptor Toll-Like 3/inmunología , Ubiquitinación/inmunología , Animales , Antivirales/inmunología , Células HEK293 , Humanos , Lisosomas/inmunología , Ratones , Transporte de Proteínas/inmunología , ARN Viral/inmunología , Transducción de Señal/inmunologíaRESUMEN
Nuclear factor-ĸB (NF-ĸB) transcription factor is a family of essential regulators of the immune response and cell proliferation and transformation. A typical factor is a heterodimer made of either p50 or p52, which are limited processing products of either p105 or p100, respectively, and a member of the Rel family of proteins, typically p65. The transcriptional program of NF-ĸB is tightly regulated by the composition of the dimers. In our previous work, we demonstrated that the ubiquitin ligase KPC1 is involved in ubiquitination and proteasomal processing of p105 to generate p50. Its overexpression and the resulting high level of p50 stimulates transcription of a broad array of tumor suppressors. Here we demonstrate that additional mechanisms are involved in the p50-mediated tumor-suppressive effect. p50 down-regulates expression of a major immune checkpoint inhibitor, the programmed cell death-ligand 1 (PD-L1), both in cells and in tumors. Importantly, the suppression is abrogated by overexpression of p65. This highlights the importance of the cellular quantities of the two different subunits of NF-ĸB which determine the composition of the dimer. While the putative p50 homodimer is tumor-suppressive, the "canonical" p50p65 heterodimer is oncogenic. We found that an additional mechanism is involved in the tumor-suppressive phenomenon: p50 up-regulates expression of the proinflammatory chemokines CCL3, CCL4, and CCL5, which in turn recruit into the tumors active natural killer (NK) cells and macrophages. Overall, p50 acts as a strong tumor suppressor via multiple mechanisms, including overexpression of tumor suppressors and modulation of the tumor microenvironment by recruiting active immune cells.
Asunto(s)
Antígeno B7-H1/metabolismo , Regulación Neoplásica de la Expresión Génica/inmunología , Subunidad p50 de NF-kappa B/metabolismo , Neoplasias/genética , Ubiquitina-Proteína Ligasas/metabolismo , Traslado Adoptivo , Animales , Antígeno B7-H1/inmunología , Línea Celular Tumoral , Quimiocinas/inmunología , Quimiocinas/metabolismo , Células HEK293 , Humanos , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/metabolismo , Células Asesinas Naturales/trasplante , Macrófagos/inmunología , Macrófagos/metabolismo , Ratones , Neoplasias/inmunología , Neoplasias/patología , Cultivo Primario de Células , Factor de Transcripción ReIA/metabolismo , Activación Transcripcional/inmunología , Microambiente Tumoral/genética , Microambiente Tumoral/inmunología , Ubiquitinación/genética , Ubiquitinación/inmunología , Regulación hacia Arriba , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
RIG-I plays important roles in pathogen sensing and activation of antiviral innate immune responses in response to RNA viruses. RIG-I-mediated signaling must be precisely controlled to maintain innate immune signaling homeostasis. Previous studies demonstrated that lysine 63 (K63)-linked polyubiquitination of RIG-I is vital for its activation, but the mechanisms through which RIG-I is deubiquitinated to control innate immune responses are not well understood. Here we identified USP27X as a negative regulator of antiviral signaling in response to RNA viruses through siRNA library screening. Further functional studies indicated that USP27X negatively modulated RIG-I-mediated antiviral signaling in a deubiquitinase-dependent manner. Mechanistically, we found that USP27X removed K63-linked polyubiquitin chains from RIG-I to negatively modulate type I interferon signaling. Collectively, these studies uncover a novel negative regulatory role of USP27X in targeting RIG-I to balance innate immune responses.
Asunto(s)
Proteína 58 DEAD Box , Inmunidad Innata/genética , Transducción de Señal , Proteasas Ubiquitina-Específicas , Virus/inmunología , Animales , Proteína 58 DEAD Box/genética , Proteína 58 DEAD Box/inmunología , Células HeLa , Células Hep G2 , Humanos , Interferón Tipo I/genética , Interferón Tipo I/inmunología , Ratones , Células RAW 264.7 , Receptores Inmunológicos , Transducción de Señal/genética , Transducción de Señal/inmunología , Proteasas Ubiquitina-Específicas/genética , Proteasas Ubiquitina-Específicas/inmunología , Ubiquitinación/genética , Ubiquitinación/inmunologíaRESUMEN
Mediator of IRF3 activation (MITA, also named as STING/ERIS/MPYS/TMEM173), is essential to DNA virus- or cytosolic DNA-triggered innate immune responses. In this study, we demonstrated the negative regulatory role of RING-finger protein (RNF) 90 in innate immune responses targeting MITA. RNF90 promoted K48-linked ubiquitination of MITA and its proteasome-dependent degradation. Overexpression of RNF90 inhibited HSV-1- or cytosolic DNA-induced immune responses whereas RNF90 knockdown had the opposite effects. Moreover, RNF90-deficient bone marrow-derived dendritic cells (BMDCs), bone marrow-derived macrophages (BMMs) and mouse embryonic fibroblasts (MEFs) exhibited increased DNA virus- or cytosolic DNA-triggered signaling and RNF90 deficiency protected mice from DNA virus infection. Taken together, our findings suggested a novel function of RNF90 in innate immunity.
Asunto(s)
Herpesvirus Humano 1/inmunología , Inmunidad Innata , Proteínas de la Membrana/inmunología , Proteolisis , Proteínas de Motivos Tripartitos/inmunología , Ubiquitina-Proteína Ligasas/inmunología , Ubiquitinación/inmunología , Animales , Células de la Médula Ósea/inmunología , Células de la Médula Ósea/virología , Células Dendríticas/inmunología , Células Dendríticas/virología , Fibroblastos/inmunología , Fibroblastos/virología , Herpesvirus Humano 1/genética , Macrófagos/inmunología , Macrófagos/virología , Proteínas de la Membrana/genética , Ratones , Ratones Noqueados , Proteínas de Motivos Tripartitos/genética , Ubiquitina-Proteína Ligasas/genética , Ubiquitinación/genéticaRESUMEN
Immune cells sense microbial products through Toll-like receptors (TLR), which trigger host defense responses including type 1 interferons (IFNs) secretion. A coding polymorphism in the protein tyrosine phosphatase nonreceptor type 22 (PTPN22) gene is a susceptibility allele for human autoimmune and infectious disease. We report that Ptpn22 selectively regulated type 1 IFN production after TLR engagement in myeloid cells. Ptpn22 promoted host antiviral responses and was critical for TLR agonist-induced, type 1 IFN-dependent suppression of inflammation in colitis and arthritis. PTPN22 directly associated with TNF receptor-associated factor 3 (TRAF3) and promotes TRAF3 lysine 63-linked ubiquitination. The disease-associated PTPN22W variant failed to promote TRAF3 ubiquitination, type 1 IFN upregulation, and type 1 IFN-dependent suppression of arthritis. The findings establish a candidate innate immune mechanism of action for a human autoimmunity "risk" gene in the regulation of host defense and inflammation.
Asunto(s)
Autoinmunidad/inmunología , Inmunidad/inmunología , Interferón Tipo I/inmunología , Proteína Tirosina Fosfatasa no Receptora Tipo 22/inmunología , Receptores Toll-Like/inmunología , Animales , Artritis/genética , Artritis/inmunología , Autoinmunidad/genética , Línea Celular , Células Cultivadas , Colitis/inducido químicamente , Colitis/genética , Colitis/inmunología , Sulfato de Dextran/inmunología , Células HEK293 , Interacciones Huésped-Patógeno/inmunología , Humanos , Inmunidad/genética , Immunoblotting , Interferón Tipo I/genética , Interferón Tipo I/metabolismo , Coriomeningitis Linfocítica/genética , Coriomeningitis Linfocítica/inmunología , Coriomeningitis Linfocítica/virología , Virus de la Coriomeningitis Linfocítica/inmunología , Virus de la Coriomeningitis Linfocítica/fisiología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Células Mieloides/inmunología , Células Mieloides/metabolismo , Proteína Tirosina Fosfatasa no Receptora Tipo 22/genética , Proteína Tirosina Fosfatasa no Receptora Tipo 22/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factor 3 Asociado a Receptor de TNF/genética , Factor 3 Asociado a Receptor de TNF/inmunología , Factor 3 Asociado a Receptor de TNF/metabolismo , Receptores Toll-Like/genética , Receptores Toll-Like/metabolismo , Ubiquitinación/inmunologíaRESUMEN
The cytosolic pattern recognition receptor NLRP3 senses host-derived danger signals and certain microbe-derived products in both humans and rodents. NLRP3 activation assembles an inflammasome complex that contains the adapter proteins ASC and caspase-1, whose activation triggers the maturation and release of the proinflammatory cytokines IL-1ß and IL-18. S5 phosphorylation of NLRP3 prevents its oligomerization and activation, whereas dephosphorylation of this residue by the phosphatase PP2A allows NLRP3 activation. However, the protein kinase that mediates NLRP3 S5 phosphorylation is unknown. In this study, we show that AKT associates with NLRP3 and phosphorylates it on S5, limiting NLRP3 oligomerization. This phosphorylation event also stabilizes NLRP3 by reducing its ubiquitination on lysine 496, which inhibits its proteasome-mediated degradation by the E3 ligase Trim31. Pharmacologic manipulation of AKT kinase activity reciprocally modulates NLRP3 inflammasome-mediated IL-1ß production. Inhibition of AKT reduced IL-1ß production following the i.p. injection of LPS into mice. We propose that AKT, Trim31, and PP2A together modulate NLRP3 protein levels and the tendency to oligomerize, thereby setting a tightly regulated threshold for NLRP3 activation.