RESUMEN
Common gamma receptor-dependent cytokines and their JAK/STAT pathways play pivotal roles in T cell immunity. Abnormal activation of this system was pervasive in diverse T cell malignancies assessed by pSTAT3/pSTAT5 phosphorylation. Activating mutations were described in some but not all cases. JAK1 and STAT3 were required for proliferation and survival of these T cell lines whether or not JAKs or STATs were mutated. Activating JAK and STAT mutations were not sufficient to initiate leukemic cell proliferation but rather only augmented signals from upstream in the cytokine pathway. Activation required the full pathway, including cytokine receptors acting as scaffolds and docking sites for required downstream JAK/STAT proteins. JAK kinase inhibitors have depressed leukemic T cell line proliferation. The insight that JAK/STAT system activation is pervasive in T cell malignancies suggests novel therapeutic approaches that include antibodies to common gamma cytokines, inhibitors of cytokine-receptor interactions, and JAK kinase inhibitors that may revolutionize therapy for T cell malignancies.
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Anticuerpos Monoclonales/uso terapéutico , Inhibidores Enzimáticos/uso terapéutico , Inmunoterapia/métodos , Quinasas Janus/metabolismo , Linfoma de Células T/inmunología , Factores de Transcripción STAT/metabolismo , Animales , Antineoplásicos/uso terapéutico , Carcinogénesis , Citocinas/inmunología , Citocinas/metabolismo , Humanos , Subunidad gamma Común de Receptores de Interleucina/metabolismo , Linfoma de Células T/terapia , Receptores de Citocinas/antagonistas & inhibidores , Transducción de SeñalRESUMEN
Mammalian blastocyst formation involves the specification of the trophectoderm followed by the differentiation of the inner cell mass into embryonic epiblast and extra-embryonic primitive endoderm (PrE). During this time, the embryo maintains a window of plasticity and can redirect its cellular fate when challenged experimentally. In this context, we found that the PrE alone was sufficient to regenerate a complete blastocyst and continue post-implantation development. We identify an in vitro population similar to the early PrE in vivo that exhibits the same embryonic and extra-embryonic potency and can form complete stem cell-based embryo models, termed blastoids. Commitment in the PrE is suppressed by JAK/STAT signaling, collaborating with OCT4 and the sustained expression of a subset of pluripotency-related transcription factors that safeguard an enhancer landscape permissive for multi-lineage differentiation. Our observations support the notion that transcription factor persistence underlies plasticity in regulative development and highlight the importance of the PrE in perturbed development.
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Blastocisto , Diferenciación Celular , Endodermo , Animales , Endodermo/metabolismo , Endodermo/citología , Ratones , Blastocisto/metabolismo , Blastocisto/citología , Linaje de la Célula , Factor 3 de Transcripción de Unión a Octámeros/metabolismo , Factor 3 de Transcripción de Unión a Octámeros/genética , Transducción de Señal , Desarrollo Embrionario , Quinasas Janus/metabolismo , Regulación del Desarrollo de la Expresión Génica , Factores de Transcripción STAT/metabolismo , Factores de Transcripción/metabolismo , Femenino , Embrión de Mamíferos/metabolismo , Embrión de Mamíferos/citologíaRESUMEN
Thrombopoietin (THPO or TPO) is an essential cytokine for hematopoietic stem cell (HSC) maintenance and megakaryocyte differentiation. Here, we report the 3.4 Å resolution cryoelectron microscopy structure of the extracellular TPO-TPO receptor (TpoR or MPL) signaling complex, revealing the basis for homodimeric MPL activation and providing a structural rationalization for genetic loss-of-function thrombocytopenia mutations. The structure guided the engineering of TPO variants (TPOmod) with a spectrum of signaling activities, from neutral antagonists to partial- and super-agonists. Partial agonist TPOmod decoupled JAK/STAT from ERK/AKT/CREB activation, driving a bias for megakaryopoiesis and platelet production without causing significant HSC expansion in mice and showing superior maintenance of human HSCs in vitro. These data demonstrate the functional uncoupling of the two primary roles of TPO, highlighting the potential utility of TPOmod in hematology research and clinical HSC transplantation.
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Receptores de Trombopoyetina , Trombopoyetina , Animales , Humanos , Ratones , Ciclo Celular , Microscopía por Crioelectrón , Receptores de Trombopoyetina/genética , Trombopoyesis , Metilación de ADNRESUMEN
Interferons (IFNs) induce an antimicrobial state, protecting tissues from infection. Many viruses inhibit IFN signaling, but whether bacterial pathogens evade IFN responses remains unclear. Here, we demonstrate that the Shigella OspC family of type-III-secreted effectors blocks IFN signaling independently of its cell death inhibitory activity. Rather, IFN inhibition was mediated by the binding of OspC1 and OspC3 to the Ca2+ sensor calmodulin (CaM), blocking CaM kinase II and downstream JAK/STAT signaling. The growth of Shigella lacking OspC1 and OspC3 was attenuated in epithelial cells and in a murine model of infection. This phenotype was rescued in both models by the depletion of IFN receptors. OspC homologs conserved in additional pathogens not only bound CaM but also inhibited IFN, suggesting a widespread virulence strategy. These findings reveal a conserved but previously undescribed molecular mechanism of IFN inhibition and demonstrate the critical role of Ca2+ and IFN targeting in bacterial pathogenesis.
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Interferones , Factores de Virulencia , Animales , Antivirales , Señalización del Calcio , Células Epiteliales/metabolismo , Interferones/metabolismo , Ratones , Factores de Virulencia/metabolismoRESUMEN
Human plasmacytoid dendritic cells (pDCs) are interleukin-3 (IL-3)-dependent cells implicated in autoimmunity, but the role of IL-3 in pDC biology is poorly understood. We found that IL-3-induced Janus kinase 2-dependent expression of SLC7A5 and SLC3A2, which comprise the large neutral amino acid transporter, was required for mammalian target of rapamycin complex 1 (mTORC1) nutrient sensor activation in response to toll-like receptor agonists. mTORC1 facilitated increased anabolic activity resulting in type I interferon, tumor necrosis factor, and chemokine production and the expression of the cystine transporter SLC7A11. Loss of function of these amino acid transporters synergistically blocked cytokine production by pDCs. Comparison of in vitro-activated pDCs with those from lupus nephritis lesions identified not only SLC7A5, SLC3A2, and SLC7A11 but also ectonucleotide pyrophosphatase-phosphodiesterase 2 (ENPP2) as components of a shared transcriptional signature, and ENPP2 inhibition also blocked cytokine production. Our data identify additional therapeutic targets for autoimmune diseases in which pDCs are implicated.
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Sistemas de Transporte de Aminoácidos/genética , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Regulación de la Expresión Génica , Sistemas de Transporte de Aminoácidos/metabolismo , Autoinmunidad , Biomarcadores , Citocinas/genética , Citocinas/metabolismo , Susceptibilidad a Enfermedades , Metabolismo Energético , Humanos , Inmunidad , Transducción de SeñalRESUMEN
Tumor-infiltrating myeloid cells (TIMs) are crucial cell populations involved in tumor immune escape, and their functions are regulated by multiple epigenetic mechanisms. The precise regulation mode of RNA N6-methyladenosine (m6A) modification in controlling TIM function is still poorly understood. Our study revealed that the increased expression of methyltransferase-like 3 (METTL3) in TIMs was correlated with the poor prognosis of colon cancer patients, and myeloid deficiency of METTL3 attenuated tumor growth in mice. METTL3 mediated m6A modification on Jak1 mRNA in TIMs, the m6A-YTHDF1 axis enhanced JAK1 protein translation efficiency and subsequent phosphorylation of STAT3. Lactate accumulated in tumor microenvironment potently induced METTL3 upregulation in TIMs via H3K18 lactylation. Interestingly, we identified two lactylation modification sites in the zinc-finger domain of METTL3, which was essential for METTL3 to capture target RNA. Our results emphasize the importance of lactylation-driven METTL3-mediated RNA m6A modification for promoting the immunosuppressive capacity of TIMs.
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Metiltransferasas , Neoplasias , Adenosina/metabolismo , Animales , Humanos , Terapia de Inmunosupresión , Metiltransferasas/genética , Metiltransferasas/metabolismo , Ratones , Células Mieloides/metabolismo , ARN , Microambiente TumoralRESUMEN
Autoinflammatory disease can result from monogenic errors of immunity. We describe a patient with early-onset multi-organ immune dysregulation resulting from a mosaic, gain-of-function mutation (S703I) in JAK1, encoding a kinase essential for signaling downstream of >25 cytokines. By custom single-cell RNA sequencing, we examine mosaicism with single-cell resolution. We find that JAK1 transcription was predominantly restricted to a single allele across different cells, introducing the concept of a mutational "transcriptotype" that differs from the genotype. Functionally, the mutation increases JAK1 activity and transactivates partnering JAKs, independent of its catalytic domain. S703I JAK1 is not only hypermorphic for cytokine signaling but also neomorphic, as it enables signaling cascades not canonically mediated by JAK1. Given these results, the patient was treated with tofacitinib, a JAK inhibitor, leading to the rapid resolution of clinical disease. These findings offer a platform for personalized medicine with the concurrent discovery of fundamental biological principles.
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Enfermedades Autoinflamatorias Hereditarias/genética , Enfermedades Autoinflamatorias Hereditarias/patología , Janus Quinasa 1/genética , Síndrome de Respuesta Inflamatoria Sistémica/genética , Síndrome de Respuesta Inflamatoria Sistémica/patología , Adolescente , COVID-19/mortalidad , Dominio Catalítico/genética , Línea Celular , Citocinas/metabolismo , Femenino , Mutación con Ganancia de Función/genética , Genotipo , Células HEK293 , Enfermedades Autoinflamatorias Hereditarias/tratamiento farmacológico , Humanos , Janus Quinasa 1/antagonistas & inhibidores , Mosaicismo , Piperidinas/uso terapéutico , Medicina de Precisión/métodos , Pirimidinas/uso terapéutico , Transducción de Señal/inmunología , Síndrome de Respuesta Inflamatoria Sistémica/tratamiento farmacológicoRESUMEN
Ten-eleven translocation (TET) proteins are dioxygenases that convert 5-methylcytosine (5mC) into 5-hydroxylmethylcytosine (5hmC) in DNA and RNA. However, their involvement in adult stem cell regulation remains unclear. Here, we identify a novel enzymatic activity-independent function of Tet in the Drosophila germline stem cell (GSC) niche. Tet activates the expression of Dpp, the fly homologue of BMP, in the ovary stem cell niche, thereby controlling GSC self-renewal. Depletion of Tet disrupts Dpp production, leading to premature GSC loss. Strikingly, both wild-type and enzyme-dead mutant Tet proteins rescue defective BMP signaling and GSC loss when expressed in the niche. Mechanistically, Tet interacts directly with Bap55 and Stat92E, facilitating recruitment of the Polybromo Brahma associated protein (PBAP) complex to the dpp enhancer and activating Dpp expression. Furthermore, human TET3 can effectively substitute for Drosophila Tet in the niche to support BMP signaling and GSC self-renewal. Our findings highlight a conserved novel catalytic activity-independent role of Tet as a scaffold protein in supporting niche signaling for adult stem cell self-renewal.
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Dioxigenasas , Proteínas de Drosophila , Drosophila melanogaster , Animales , Femenino , Humanos , Diferenciación Celular/genética , Drosophila/genética , Drosophila melanogaster/genética , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Células Germinativas/metabolismo , Nicho de Células Madre/fisiología , Células Madre/metabolismo , Dioxigenasas/metabolismoRESUMEN
Inborn errors of immunity (IEIs) encompass a diverse spectrum of genetic disorders that disrupt the intricate mechanisms of the immune system, leading to a variety of clinical manifestations. Traditionally associated with an increased susceptibility to recurrent infections, IEIs have unveiled a broader clinical landscape, encompassing immune dysregulation disorders characterized by autoimmunity, severe allergy, lymphoproliferation, and even malignancy. This review delves into the intricate interplay between IEIs and the JAK-STAT signaling pathway, a critical regulator of immune homeostasis. Mutations within this pathway can lead to a wide array of clinical presentations, even within the same gene. This heterogeneity poses a significant challenge, necessitating individually tailored therapeutic approaches to effectively manage the diverse manifestations of these disorders. Additionally, JAK-STAT pathway defects can lead to simultaneous susceptibility to both infection and immune dysregulation. JAK inhibitors, with their ability to suppress JAK-STAT signaling, have emerged as powerful tools in controlling immune dysregulation. However, questions remain regarding the optimal selection and dosing regimens for each specific condition. Hematopoietic stem cell transplantation (HSCT) holds promise as a curative therapy for many JAK-STAT pathway disorders, but this procedure carries significant risks. The use of JAK inhibitors as a bridge to HSCT has been proposed as a potential strategy to mitigate these risks.
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Enfermedades del Sistema Inmune , Inhibidores de las Cinasas Janus , Humanos , Transducción de Señal , Inhibidores de las Cinasas Janus/uso terapéutico , Inhibidores de las Cinasas Janus/farmacología , Quinasas Janus/metabolismo , Factores de Transcripción STAT/metabolismoRESUMEN
The gene expression programs that define the identity of each cell are controlled by master transcription factors (TFs) that bind cell-type-specific enhancers, as well as signaling factors, which bring extracellular stimuli to these enhancers. Recent studies have revealed that master TFs form phase-separated condensates with the Mediator coactivator at super-enhancers. Here, we present evidence that signaling factors for the WNT, TGF-ß, and JAK/STAT pathways use their intrinsically disordered regions (IDRs) to enter and concentrate in Mediator condensates at super-enhancers. We show that the WNT coactivator ß-catenin interacts both with components of condensates and DNA-binding factors to selectively occupy super-enhancer-associated genes. We propose that the cell-type specificity of the response to signaling is mediated in part by the IDRs of the signaling factors, which cause these factors to partition into condensates established by the master TFs and Mediator at genes with prominent roles in cell identity.
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Elementos de Facilitación Genéticos/genética , Complejo Mediador/metabolismo , Factores de Transcripción/metabolismo , Animales , Línea Celular , Regulación de la Expresión Génica/fisiología , Humanos , Proteínas Intrínsecamente Desordenadas/metabolismo , Complejo Mediador/fisiología , Factores de Transcripción STAT/metabolismo , Factor de Transcripción STAT3/metabolismo , Transducción de Señal/fisiología , Proteína smad3/metabolismo , Proteínas de la Superfamilia TGF-beta/metabolismo , Transcripción Genética , Vía de Señalización Wnt , beta Catenina/metabolismoRESUMEN
Many organs of Drosophila show stereotypical left-right (LR) asymmetry; however, the underlying mechanisms remain elusive. Here, we have identified an evolutionarily conserved ubiquitin-binding protein, AWP1/Doctor No (Drn), as a factor required for LR asymmetry in the embryonic anterior gut. We found that drn is essential in the circular visceral muscle cells of the midgut for JAK/STAT signaling, which contributes to the first known cue for anterior gut lateralization via LR asymmetric nuclear rearrangement. Embryos homozygous for drn and lacking its maternal contribution showed phenotypes similar to those with depleted JAK/STAT signaling, suggesting that Drn is a general component of JAK/STAT signaling. Absence of Drn resulted in specific accumulation of Domeless (Dome), the receptor for ligands in the JAK/STAT signaling pathway, in intracellular compartments, including ubiquitylated cargos. Dome colocalized with Drn in wild-type Drosophila. These results suggest that Drn is required for the endocytic trafficking of Dome, which is a crucial step for activation of JAK/STAT signaling and the subsequent degradation of Dome. The roles of AWP1/Drn in activating JAK/STAT signaling and in LR asymmetric development may be conserved in various organisms.
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Proteínas de Drosophila , Drosophila , Animales , Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Proteínas de Drosophila/metabolismo , Transducción de Señal/fisiología , Endocitosis/genética , Quinasas Janus/genética , Quinasas Janus/metabolismo , Factores de Transcripción STAT/genética , Factores de Transcripción STAT/metabolismoRESUMEN
Host defense requires the specification of CD4+ helper T (Th) cells into distinct fates, including Th1 cells that preferentially produce interferon-γ (IFN-γ). IFN-γ, a member of a large family of anti-pathogenic and anti-tumor IFNs, induces T-bet, a lineage-defining transcription factor for Th1 cells, which in turn supports IFN-γ production in a feed-forward manner. Herein, we show that a cell-intrinsic role of T-bet influences how T cells perceive their secreted product in the environment. In the absence of T-bet, IFN-γ aberrantly induced a type I IFN transcriptomic program. T-bet preferentially repressed genes and pathways ordinarily activated by type I IFNs to ensure that its transcriptional response did not evoke an aberrant amplification of type I IFN signaling circuitry, otherwise triggered by its own product. Thus, in addition to promoting Th1 effector commitment, T-bet acts as a repressor in differentiated Th1 cells to prevent abberant autocrine type I IFN and downstream signaling.
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Comunicación Autocrina , Coriomeningitis Linfocítica/inmunología , Virus de la Coriomeningitis Linfocítica/inmunología , Proteínas de Dominio T Box/metabolismo , Células TH1/inmunología , Toxoplasma/inmunología , Toxoplasmosis/inmunología , Animales , Diferenciación Celular , Proliferación Celular , Células Cultivadas , Humanos , Interferón Tipo I/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Transducción de Señal , Proteínas de Dominio T Box/genética , Células TH1/microbiología , Células TH1/virología , TranscriptomaRESUMEN
Natural killer (NK) cells and type 1 innate lymphoid cells (ILC1) require signal transducer and activator of transcription 4 (STAT4) to elicit rapid effector responses and protect against pathogens. By combining genetic and transcriptomic approaches, we uncovered divergent roles for STAT4 in regulating effector differentiation of these functionally related cell types. Stat4 deletion in Ncr1-expressing cells led to impaired NK cell terminal differentiation as well as to an unexpected increased generation of cytotoxic ILC1 during intestinal inflammation. Mechanistically, Stat4-deficient ILC1 exhibited upregulation of gene modules regulated by STAT5 in vivo and an aberrant effector differentiation upon in vitro stimulation with IL-2, used as a prototypical STAT5 activator. Moreover, STAT4 expression in NCR+ innate lymphocytes restrained gut inflammation in the dextran sulfate sodium-induced colitis model limiting pathogenic production of IL-13 from adaptive CD4+ T cells in the large intestine. Collectively, our data shed light on shared and distinctive mechanisms of STAT4-regulated transcriptional control in NK cells and ILC1 required for intestinal inflammatory responses.
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Antineoplásicos , Factor de Transcripción STAT5 , Humanos , Inmunidad Innata , Diferenciación Celular , Células Asesinas Naturales , Inflamación , Factor de Transcripción STAT4/genéticaRESUMEN
Drosophila melanogaster is an ideal model organism for investigating spermatogenesis due to its powerful genetics, conserved genes and visible morphology of germ cells during sperm production. Our previous work revealed that ocnus (ocn) knockdown resulted in male sterility, and CG9920 was identified as a significantly downregulated protein in fly abdomen after ocn knockdown, suggesting a role of CG9920 in male reproduction. In this study, we found that CG9920 was highly expressed in fly testes. CG9920 knockdown in fly testes caused male infertility with no mature sperms in seminal vesicles. Immunofluorescence staining showed that depletion of CG9920 resulted in scattered spermatid nuclear bundles, fewer elongation cones that did not migrate to the anterior region of the testis, and almost no individualization complexes. Transmission electron microscopy revealed that CG9920 knockdown severely disrupted mitochondrial morphogenesis during spermatogenesis. Notably, we found that CG9920 might not directly interact with Ocn, but rather was inhibited by STAT92E, which itself was indirectly affected by Ocn. We propose a possible novel pathway essential for spermatogenesis in D. melanogaster, whereby Ocn indirectly induces CG9920 expression, potentially counteracting its inhibition by the JAK-STAT signaling pathway.
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Proteínas de Drosophila , Drosophila melanogaster , Mitocondrias , Espermatogénesis , Testículo , Animales , Espermatogénesis/genética , Espermatogénesis/fisiología , Masculino , Drosophila melanogaster/metabolismo , Proteínas de Drosophila/metabolismo , Proteínas de Drosophila/genética , Mitocondrias/metabolismo , Testículo/metabolismo , Morfogénesis/genética , Transducción de Señal , Infertilidad Masculina/genética , Infertilidad Masculina/metabolismo , Técnicas de Silenciamiento del Gen , Factores de Transcripción STAT/metabolismo , Espermátides/metabolismoRESUMEN
Nonresponsive celiac disease (CeD) is relatively common. It is generally attributed to persistent gluten exposure and resolves after correction of diet errors. However, other complications of CeD and disorders clinically mimicking CeD need to be excluded. Novel therapies are being evaluated to facilitate mucosal recovery, which might benefit patients with nonresponsive CeD. Refractory CeD (RCeD) is rare and is divided into 2 types. The etiology of type I RCeD is unclear. A switch to gluten-independent autoimmunity is suspected in some patients. In contrast, type II RCeD represents a low-grade intraepithelial lymphoma. Type I RCeD remains a diagnosis of exclusion, requiring ruling out gluten intake and other nonmalignant causes of villous atrophy. Diagnosis of type II RCeD relies on the demonstration of a clonal population of neoplastic intraepithelial lymphocytes with an atypical immunophenotype. Type I RCeD and type II RCeD generally respond to open-capsule budesonide, but the latter has a dismal prognosis due to severe malnutrition and frequent progression to enteropathy-associated T-cell lymphoma; more efficient therapy is needed.
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Enfermedad Celíaca , Enfermedad Celíaca/diagnóstico , Enfermedad Celíaca/terapia , Enfermedad Celíaca/inmunología , Enfermedad Celíaca/dietoterapia , Humanos , Dieta Sin Gluten , Mucosa Intestinal/patología , Mucosa Intestinal/inmunología , Mucosa Intestinal/efectos de los fármacos , Glútenes/inmunología , Glútenes/efectos adversos , Resultado del Tratamiento , Budesonida/uso terapéuticoRESUMEN
Visual information is transmitted from the eye to the brain along the optic nerve, a structure composed of retinal ganglion cell (RGC) axons. The optic nerve is highly vulnerable to damage in neurodegenerative diseases, such as glaucoma, and there are currently no FDA-approved drugs or therapies to protect RGCs from death. Zebrafish possess remarkable neuroprotective and regenerative abilities. Here, utilizing an optic nerve transection (ONT) injury and an RNA-seq-based approach, we identify genes and pathways active in RGCs that may modulate their survival. Through pharmacological perturbation, we demonstrate that Jak/Stat pathway activity is required for RGC survival after ONT. Furthermore, we show that immune responses directly contribute to RGC death after ONT; macrophages/microglia are recruited to the retina and blocking neuroinflammation or depleting these cells after ONT rescues survival of RGCs. Taken together, these data support a model in which crosstalk between macrophages/microglia and RGCs, mediated by Jak/Stat pathway activity, regulates RGC survival after optic nerve injury.
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Inmunidad Innata , Quinasas Janus/inmunología , Traumatismos del Nervio Óptico/inmunología , Células Ganglionares de la Retina/inmunología , Factores de Transcripción STAT/inmunología , Transducción de Señal/inmunología , Proteínas de Pez Cebra/inmunología , Pez Cebra/inmunología , Animales , Animales Modificados Genéticamente , Femenino , Quinasas Janus/genética , Masculino , Traumatismos del Nervio Óptico/genética , Factores de Transcripción STAT/genética , Transducción de Señal/genética , Pez Cebra/genética , Proteínas de Pez Cebra/genéticaRESUMEN
Hemimetabolous insects, such as the two-spotted cricket Gryllus bimaculatus, can recover lost tissues, in contrast to the limited regenerative abilities of human tissues. Following cricket leg amputation, the wound surface is covered by the wound epidermis, and plasmatocytes, which are insect macrophages, accumulate in the wound region. Here, we studied the function of Toll-related molecules identified by comparative RNA sequencing during leg regeneration. Of the 11 Toll genes in the Gryllus genome, expression of Toll2-1, Toll2-2 and Toll2-5 was upregulated during regeneration. RNA interference (RNAi) of Toll, Toll2-1, Toll2-2, Toll2-3 or Toll2-4 produced regeneration defects in more than 50% of crickets. RNAi of Toll2-2 led to a decrease in the ratio of S- and M-phase cells, reduced expression of JAK/STAT signalling genes, and reduced accumulation of plasmatocytes in the blastema. Depletion of plasmatocytes in crickets using clodronate also produced regeneration defects, as well as fewer proliferating cells in the regenerating legs. Plasmatocyte depletion also downregulated the expression of Toll and JAK/STAT signalling genes in the regenerating legs. These results suggest that Spz-Toll-related signalling in plasmatocytes promotes leg regeneration through blastema cell proliferation by regulating the Upd-JAK/STAT signalling pathway.
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Gryllidae/metabolismo , Miembro Posterior/fisiología , Proteínas de Insectos/biosíntesis , Regeneración , Transducción de Señal , Receptores Toll-Like/biosíntesis , Animales , Regulación de la Expresión Génica , Gryllidae/genética , Proteínas de Insectos/genética , Receptores Toll-Like/genéticaRESUMEN
African swine fever (ASF) is an acute, hemorrhagic, and severe infectious disease caused by ASF virus (ASFV) infection. At present, there are still no safe and effective drugs and vaccines to prevent ASF. Mining the important proteins encoded by ASFV that affect the virulence and replication of ASFV is the key to developing effective vaccines and drugs. In this study, ASFV pH240R, a capsid protein of ASFV, was found to inhibit the type I interferon (IFN) signaling pathway. Mechanistically, pH240R interacted with IFNAR1 and IFNAR2 to disrupt the interaction of IFNAR1-TYK2 and IFNAR2-JAK1. Additionally, pH240R inhibited the phosphorylation of IFNAR1, TYK2, and JAK1 induced by IFN-α, resulting in the suppression of the nuclear import of STAT1 and STAT2 and the expression of IFN-stimulated genes (ISGs). Consistent with these results, H240R-deficient ASFV (ASFV-∆H240R) infection induced more ISGs in porcine alveolar macrophages compared with its parental ASFV HLJ/18. We also found that pH240R enhanced viral replication via inhibition of ISGs expression. Taken together, our results clarify that pH240R enhances ASFV replication by inhibiting the JAK-STAT signaling pathway, which highlights the possibility of pH240R as a potential drug target.IMPORTANCEThe innate immune response is the host's first line of defense against pathogen infection, which has been reported to affect the replication and virulence of African swine fever virus (ASFV) isolates. Identification of ASFV-encoded proteins that affect the virulence and replication of ASFV is the key step in developing more effective vaccines and drugs. In this study, we found that pH240R interacted with IFNAR1 and IFNAR2 by disrupting the interaction of IFNAR1-TYK2 and IFNAR2-JAK1, resulting in the suppression of the expression of interferon (IFN)-stimulated genes (ISGs). Consistent with these results, H240R-deficient ASFV (ASFV-∆H240R) infection induces more ISGs' expression compared with its parental ASFV HLJ/18. We also found that pH240R enhanced viral replication via inhibition of ISGs' expression. Taken together, our findings showed that pH240R enhances ASFV replication by inhibiting the IFN-JAK-STAT axis, which highlights the possibility of pH240R as a potential drug target.
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Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Interferón Tipo I , Animales , Fiebre Porcina Africana/metabolismo , Fiebre Porcina Africana/virología , Virus de la Fiebre Porcina Africana/metabolismo , Interferón Tipo I/metabolismo , Transducción de Señal/fisiología , Porcinos , Vacunas/metabolismo , Replicación ViralRESUMEN
Porcine deltacoronavirus (PDCoV) is an enteric pathogenic coronavirus that causes acute and severe watery diarrhea in piglets and has the ability of cross-species transmission, posing a great threat to swine production and public health. The interferon (IFN)-mediated signal transduction represents an important component of virus-host interactions and plays an essential role in regulating viral infection. Previous studies have suggested that multifunctional viral proteins encoded by coronaviruses antagonize the production of IFN via various means. However, the function of these viral proteins in regulating IFN-mediated signaling pathways is largely unknown. In this study, we demonstrated that PDCoV and its encoded nucleocapsid (N) protein antagonize type I IFN-mediated JAK-STAT signaling pathway. We identified that PDCoV infection stimulated but delayed the production of IFN-stimulated genes (ISGs). In addition, PDCoV inhibited JAK-STAT signal transduction by targeting the nuclear translocation of STAT1 and ISGF3 formation. Further evidence showed that PDCoV N is the essential protein involved in the inhibition of type I IFN signaling by targeting STAT1 nuclear translocation via its C-terminal domain. Mechanistically, PDCoV N targets STAT1 by interacting with it and subsequently inhibiting its nuclear translocation. Furthermore, PDCoV N inhibits STAT1 nuclear translocation by specifically targeting KPNA2 degradation through the lysosomal pathway, thereby inhibiting the activation of downstream sensors in the JAK-STAT signaling pathway. Taken together, our results reveal a novel mechanism by which PDCoV N interferes with the host antiviral response.IMPORTANCEPorcine deltacoronavirus (PDCoV) is a novel enteropathogenic coronavirus that receives increased attention and seriously threatens the pig industry and public health. Understanding the underlying mechanism of PDCoV evading the host defense during infection is essential for developing targeted drugs and effective vaccines against PDCoV. This study demonstrated that PDCoV and its encoded nucleocapsid (N) protein antagonize type I interferon signaling by targeting STAT1, which is a crucial signal sensor in the JAK-STAT signaling pathway. Further experiments suggested that PDCoV N-mediated inhibition of the STAT1 nuclear translocation involves the degradation of KPNA2, and the lysosome plays a role in KPNA2 degradation. This study provides new insights into the regulation of PDCoV N in the JAK-STAT signaling pathway and reveals a novel mechanism by which PDCoV evades the host antiviral response. The novel findings may guide us to discover new therapeutic targets and develop live attenuated vaccines for PDCoV infection.
Asunto(s)
Deltacoronavirus , Proteínas de la Nucleocápside , Factor de Transcripción STAT1 , Transducción de Señal , Animales , Porcinos , Factor de Transcripción STAT1/metabolismo , Deltacoronavirus/metabolismo , Proteínas de la Nucleocápside/metabolismo , Humanos , Quinasas Janus/metabolismo , Enfermedades de los Porcinos/virología , Enfermedades de los Porcinos/metabolismo , alfa Carioferinas/metabolismo , Interferón Tipo I/metabolismo , Infecciones por Coronavirus/virología , Infecciones por Coronavirus/metabolismo , Células HEK293 , Línea Celular , Proteolisis , Interacciones Huésped-PatógenoRESUMEN
Interferons (IFNs) are cytokines produced and secreted by immune cells when viruses, tumor cells, and so forth, invade the body. Their biological effects are diverse, including antiviral, cell growth-inhibiting, and antitumor effects. The main subclasses of interferons include type-I (e.g., IFN-α and IFN-ß) and type-II (IFN-γ), which activate intracellular signals by binding to type-I and type-II IFN receptors, respectively. We have previously shown that when macrophages are treated with supersulfide donors, which have polysulfide structures in which three or more sulfur atoms are linked within the molecules, IFN-ß-induced cellular responses, including signal transducer and activator of transcription 1 (STAT1) phosphorylation and inducible nitric oxide synthase (iNOS) expression, were strongly suppressed. However, the subfamily specificity of the suppression of IFN signals by supersulfides and the mechanism of this suppression are unknown. This study demonstrated that supersulfide donor N-acetyl-L-cysteine tetrasulfide (NAC-S2) can inhibit IFN signaling in macrophages stimulated not only with IFN-α/ß but also with IFN-γ. Our data suggest that NAC-S2 blocks phosphorylation of Janus kinases (JAKs), thereby contributes to the inhibition of phosphorylation of STAT1. Under the current experimental conditions, hydrogen sulfide (H2S) donor NaHS failed to inhibit IFN signaling. Similar to NAC-S2, carbohydrate-based supersulfide donor thioglucose tetrasulfide (TGS4) was capable of strongly inhibiting tumor necrosis factor-αproduction, iNOS expression, and nitric oxide production from macrophages stimulated with lipopolysaccharide. Further understanding of molecular mechanisms how supersulfide donors exhibit their inhibitory actions towards JAK/STAT signaling is necessary basis for development of supersulfide-based therapeutic strategy against autoimmune disorders with dysregulated IFN signaling.