RESUMEN
Cytokines are secreted or otherwise released polypeptide factors that exert autocrine and/or paracrine actions, with most cytokines acting in the immune and/or hematopoietic system. They are typically pleiotropic, controlling development, cell growth, survival, and/or differentiation. Correspondingly, cytokines are clinically important, and augmenting or attenuating cytokine signals can have deleterious or therapeutic effects. Besides physiological fine-tuning of cytokine signals, altering the nature or potency of the signal can be important in pathophysiological responses and can also provide novel therapeutic approaches. Here, we give an overview of cytokines, their signaling and actions, and the physiological mechanisms and pharmacologic strategies to fine-tune their actions. In particular, the differential utilization of STAT proteins by a single cytokine or by different cytokines and STAT dimerization versus tetramerization are physiological mechanisms of fine-tuning, whereas anticytokine and anticytokine receptor antibodies and cytokines with altered activities, including cytokine superagonists, partial agonists, and antagonists, represent new ways of fine-tuning cytokine signals.
Asunto(s)
Citocinas/metabolismo , Inmunoterapia/tendencias , Animales , Citocinas/genética , Humanos , Inmunidad Humoral , Inmunomodulación , Multimerización de Proteína , Factores de Transcripción STAT/metabolismo , Transducción de Señal/inmunologíaRESUMEN
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.
Asunto(s)
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.
Asunto(s)
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.
Asunto(s)
Receptores de Trombopoyetina , Trombopoyetina , Animales , Humanos , Ratones , Ciclo Celular , Microscopía por Crioelectrón , Receptores de Trombopoyetina/genética , Trombopoyesis , Metilación de ADNRESUMEN
Pathogen infection and tissue injury are universal insults that disrupt homeostasis. Innate immunity senses microbial infections and induces cytokines/chemokines to activate resistance mechanisms. Here, we show that, in contrast to most pathogen-induced cytokines, interleukin-24 (IL-24) is predominately induced by barrier epithelial progenitors after tissue injury and is independent of microbiome or adaptive immunity. Moreover, Il24 ablation in mice impedes not only epidermal proliferation and re-epithelialization but also capillary and fibroblast regeneration within the dermal wound bed. Conversely, ectopic IL-24 induction in the homeostatic epidermis triggers global epithelial-mesenchymal tissue repair responses. Mechanistically, Il24 expression depends upon both epithelial IL24-receptor/STAT3 signaling and hypoxia-stabilized HIF1α, which converge following injury to trigger autocrine and paracrine signaling involving IL-24-mediated receptor signaling and metabolic regulation. Thus, parallel to innate immune sensing of pathogens to resolve infections, epithelial stem cells sense injury signals to orchestrate IL-24-mediated tissue repair.
Asunto(s)
Citocinas , Heridas y Lesiones , Animales , Ratones , Inmunidad Adaptativa , Quimiocinas , Epidermis , Inmunidad Innata , Heridas y Lesiones/inmunologíaRESUMEN
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.
Asunto(s)
Interferones , Factores de Virulencia , Animales , Antivirales , Señalización del Calcio , Células Epiteliales/metabolismo , Interferones/metabolismo , Ratones , Factores de Virulencia/metabolismoRESUMEN
The central pathogen-immune interface in tuberculosis is the granuloma, a complex host immune structure that dictates infection trajectory and physiology. Granuloma macrophages undergo a dramatic transition in which entire epithelial modules are induced and define granuloma architecture. In tuberculosis, relatively little is known about the host signals that trigger this transition. Using the zebrafish-Mycobacterium marinum model, we identify the basis of granuloma macrophage transformation. Single-cell RNA-sequencing analysis of zebrafish granulomas and analysis of Mycobacterium tuberculosis-infected macaques reveal that, even in the presence of robust type 1 immune responses, countervailing type 2 signals associate with macrophage epithelialization. We find that type 2 immune signaling, mediated via stat6, is absolutely required for epithelialization and granuloma formation. In mixed chimeras, stat6 acts cell autonomously within macrophages, where it is required for epithelioid transformation and incorporation into necrotic granulomas. These findings establish the signaling pathway that produces the hallmark structure of mycobacterial infection.
Asunto(s)
Granuloma/patología , Inmunidad/fisiología , Infecciones por Mycobacterium no Tuberculosas/patología , Animales , Animales Modificados Genéticamente/genética , Animales Modificados Genéticamente/metabolismo , Cadherinas/genética , Cadherinas/metabolismo , Diferenciación Celular , Modelos Animales de Enfermedad , Células Epitelioides/citología , Células Epitelioides/inmunología , Células Epitelioides/metabolismo , Granuloma/inmunología , Granuloma/metabolismo , Células Madre Hematopoyéticas/citología , Células Madre Hematopoyéticas/metabolismo , Interferón gamma/metabolismo , Interleucina-12/metabolismo , Macrófagos/citología , Macrófagos/inmunología , Macrófagos/metabolismo , Infecciones por Mycobacterium no Tuberculosas/inmunología , Mycobacterium marinum/aislamiento & purificación , Mycobacterium marinum/fisiología , Necrosis , ARN Guía de Kinetoplastida/metabolismo , Receptores de Interleucina-4/antagonistas & inhibidores , Receptores de Interleucina-4/genética , Receptores de Interleucina-4/metabolismo , Factor de Transcripción STAT6/antagonistas & inhibidores , Factor de Transcripción STAT6/genética , Factor de Transcripción STAT6/metabolismo , Transducción de Señal , Pez Cebra/crecimiento & desarrollo , Pez Cebra/metabolismoRESUMEN
Accumulation of senescent cells in organs and tissues is a hallmark of aging and known to contribute to age-related diseases. Although aging-associated immune dysfunction, or immunosenescence, is known to contribute to this process, the underlying mechanism remains elusive. Here, we report that type 2 cytokine signaling deficiency accelerated aging and, conversely, that the interleukin-4 (IL-4)-STAT6 pathway protected macrophages from senescence. Mechanistically, activated STAT6 promoted the expression of genes involved in DNA repair both via homologous recombination and Fanconi anemia pathways. Conversely, STAT6 deficiency induced release of nuclear DNA into the cytoplasm to promote tissue inflammation and organismal aging. Importantly, we demonstrate that IL-4 treatment prevented macrophage senescence and improved the health span of aged mice to an extent comparable to senolytic treatment, with further additive effects when combined. Together, our findings support that type 2 cytokine signaling protects macrophages from immunosenescence and thus hold therapeutic potential for improving healthy aging.
Asunto(s)
Senescencia Celular , Interleucina-4 , Animales , Ratones , Interleucina-4/metabolismo , Envejecimiento/genética , Macrófagos , InflamaciónRESUMEN
Macrophages are critical to turn noninflamed "cold tumors" into inflamed "hot tumors". Emerging evidence indicates abnormal cholesterol metabolites in the tumor microenvironment (TME) with unclear function. Here, we uncovered the inducible expression of cholesterol-25-hydroxylase (Ch25h) by interleukin-4 (IL-4) and interleukin-13 (IL-13) via the transcription factor STAT6, causing 25-hydroxycholesterol (25HC) accumulation. scRNA-seq analysis confirmed that CH25Hhi subsets were enriched in immunosuppressive macrophage subsets and correlated to lower survival rates in pan-cancers. Targeting CH25H abrogated macrophage immunosuppressive function to enhance infiltrating T cell numbers and activation, which synergized with anti-PD-1 to improve anti-tumor efficacy. Mechanically, lysosome-accumulated 25HC competed with cholesterol for GPR155 binding to inhibit the kinase mTORC1, leading to AMPKα activation and metabolic reprogramming. AMPKα also phosphorylated STAT6 Ser564 to enhance STAT6 activation and ARG1 production. Together, we propose CH25H as an immunometabolic checkpoint, which manipulates macrophage fate to reshape CD8+ T cell surveillance and anti-tumor response.
Asunto(s)
Hidroxicolesteroles , Lisosomas , Macrófagos , Microambiente Tumoral , Animales , Hidroxicolesteroles/metabolismo , Ratones , Macrófagos/inmunología , Macrófagos/metabolismo , Humanos , Lisosomas/metabolismo , Microambiente Tumoral/inmunología , Factor de Transcripción STAT6/metabolismo , Adenilato Quinasa/metabolismo , Ratones Endogámicos C57BL , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Transducción de Señal , Reprogramación MetabólicaRESUMEN
Obesity is a major driver of cancer, especially hepatocellular carcinoma (HCC). The prevailing view is that non-alcoholic steatohepatitis (NASH) and fibrosis or cirrhosis are required for HCC in obesity. Here, we report that NASH and fibrosis and HCC in obesity can be dissociated. We show that the oxidative hepatic environment in obesity inactivates the STAT-1 and STAT-3 phosphatase T cell protein tyrosine phosphatase (TCPTP) and increases STAT-1 and STAT-3 signaling. TCPTP deletion in hepatocytes promoted T cell recruitment and ensuing NASH and fibrosis as well as HCC in obese C57BL/6 mice that normally do not develop NASH and fibrosis or HCC. Attenuating the enhanced STAT-1 signaling prevented T cell recruitment and NASH and fibrosis but did not prevent HCC. By contrast, correcting STAT-3 signaling prevented HCC without affecting NASH and fibrosis. TCPTP-deletion in hepatocytes also markedly accelerated HCC in mice treated with a chemical carcinogen that promotes HCC without NASH and fibrosis. Our studies reveal how obesity-associated hepatic oxidative stress can independently contribute to the pathogenesis of NASH, fibrosis, and HCC.
Asunto(s)
Carcinoma Hepatocelular/patología , Neoplasias Hepáticas/patología , Enfermedad del Hígado Graso no Alcohólico/patología , Obesidad/patología , Factor de Transcripción STAT1/metabolismo , Factor de Transcripción STAT3/metabolismo , Animales , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Carcinoma Hepatocelular/metabolismo , Dieta Alta en Grasa , Modelos Animales de Enfermedad , Hepatocitos/metabolismo , Humanos , Hígado/metabolismo , Hígado/patología , Cirrosis Hepática/metabolismo , Cirrosis Hepática/patología , Neoplasias Hepáticas/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Obesidad/metabolismo , Estrés Oxidativo , Proteína Tirosina Fosfatasa no Receptora Tipo 2/deficiencia , Proteína Tirosina Fosfatasa no Receptora Tipo 2/genética , Proteína Tirosina Fosfatasa no Receptora Tipo 2/metabolismo , Transducción de SeñalRESUMEN
In colorectal cancer patients, a high density of cytotoxic CD8+ T cells in tumors is associated with better prognosis. Using a Stat3 loss-of-function approach in two wnt/ß-catenin-dependent autochthonous models of sporadic intestinal tumorigenesis, we unravel a complex intracellular process in intestinal epithelial cells (IECs) that controls the induction of a CD8+ T cell based adaptive immune response. Elevated mitophagy in IECs causes iron(II)-accumulation in epithelial lysosomes, in turn, triggering lysosomal membrane permeabilization. Subsequent release of proteases into the cytoplasm augments MHC class I presentation and activation of CD8+ T cells via cross-dressing of dendritic cells. Thus, our findings highlight a so-far-unrecognized link between mitochondrial function, lysosomal integrity, and MHC class I presentation in IECs and suggest that therapies triggering mitophagy or inducing LMP in IECs may prove successful in shifting the balance toward anti-tumor immunity in colorectal cancer.
Asunto(s)
Inmunidad Adaptativa , Mitofagia , Inmunidad Adaptativa/efectos de los fármacos , Animales , Azoximetano/toxicidad , Linfocitos T CD8-positivos/citología , Linfocitos T CD8-positivos/efectos de los fármacos , Linfocitos T CD8-positivos/metabolismo , Permeabilidad de la Membrana Celular , Neoplasias Colorrectales/mortalidad , Neoplasias Colorrectales/patología , Citocinas/metabolismo , Células Dendríticas/citología , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Femenino , Compuestos Ferrosos/metabolismo , Humanos , Interferón gamma/metabolismo , Interferón gamma/farmacología , Mucosa Intestinal/citología , Mucosa Intestinal/efectos de los fármacos , Mucosa Intestinal/metabolismo , Lisosomas/metabolismo , Masculino , Ratones , Ratones Noqueados , Mitofagia/efectos de los fármacos , Factor de Transcripción STAT3/genética , Factor de Transcripción STAT3/metabolismo , Tasa de SupervivenciaRESUMEN
Rewiring exhausted CD8+ T (Tex) cells toward functional states remains a therapeutic challenge. Tex cells are epigenetically programmed by the transcription factor Tox. However, epigenetic remodeling occurs as Tex cells transition from progenitor (Texprog) to intermediate (Texint) and terminal (Texterm) subsets, suggesting development flexibility. We examined epigenetic transitions between Tex cell subsets and revealed a reciprocally antagonistic circuit between Stat5a and Tox. Stat5 directed Texint cell formation and re-instigated partial effector biology during this Texprog-to-Texint cell transition. Constitutive Stat5a activity antagonized Tox and rewired CD8+ T cells from exhaustion to a durable effector and/or natural killer (NK)-like state with superior anti-tumor potential. Temporal induction of Stat5 activity in Tex cells using an orthogonal IL-2:IL2Rß-pair fostered Texint cell accumulation, particularly upon PD-L1 blockade. Re-engaging Stat5 also partially reprogrammed the epigenetic landscape of exhaustion and restored polyfunctionality. These data highlight therapeutic opportunities of manipulating the IL-2-Stat5 axis to rewire Tex cells toward more durably protective states.
Asunto(s)
Linfocitos T CD8-positivos , Factores de Transcripción , Factores de Transcripción/genética , Interleucina-2 , Regulación de la Expresión Génica , Receptor de Muerte Celular Programada 1/metabolismoRESUMEN
Interferon-α (IFNα) signaling is essential for antiviral response via induction of IFN-stimulated genes (ISGs). Through a non-biased high-throughput RNAi screening of 711 known epigenetic modifiers in cellular models of IFNα-mediated inhibition of HBV replication, we identified methyltransferase SETD2 as a critical amplifier of IFNα-mediated antiviral immunity. Conditional knockout mice with hepatocyte-specific deletion of Setd2 exhibit enhanced HBV infection. Mechanistically, SETD2 directly mediates STAT1 methylation on lysine 525 via its methyltransferase activity, which reinforces IFN-activated STAT1 phosphorylation and antiviral cellular response. In addition, SETD2 selectively catalyzes the tri-methylation of H3K36 on promoters of some ISGs such as ISG15, leading to gene activation. Our study identifies STAT1 methylation on K525 catalyzed by the methyltransferase SETD2 as an essential signaling event for IFNα-dependent antiviral immunity and indicates potential of SETD2 in controlling viral infections.
Asunto(s)
Virus de la Hepatitis B/fisiología , Hepatitis B Crónica/inmunología , N-Metiltransferasa de Histona-Lisina/metabolismo , Interferón-alfa/inmunología , Factor de Transcripción STAT1/genética , Animales , Línea Celular , Línea Celular Tumoral , Epigénesis Genética , Hepatitis B Crónica/virología , Hepatocitos/metabolismo , Histonas/metabolismo , Humanos , Ratones , Fosforilación , Dominios Proteicos , Interferencia de ARN , Transcripción Genética , Replicación ViralRESUMEN
The epithelium is an integral component of mucosal barrier and host immunity. Following helminth infection, the intestinal epithelial cells secrete "alarmin" cytokines, such as interleukin-25 (IL-25) and IL-33, to initiate the type 2 immune responses for helminth expulsion and tolerance. However, it is unknown how helminth infection and the resulting cytokine milieu drive epithelial remodeling and orchestrate alarmin secretion. Here, we report that epithelial O-linked N-Acetylglucosamine (O-GlcNAc) protein modification was induced upon helminth infections. By modifying and activating the transcription factor STAT6, O-GlcNAc transferase promoted the transcription of lineage-defining Pou2f3 in tuft cell differentiation and IL-25 production. Meanwhile, STAT6 O-GlcNAcylation activated the expression of Gsdmc family genes. The membrane pore formed by GSDMC facilitated the unconventional secretion of IL-33. GSDMC-mediated IL-33 secretion was indispensable for effective anti-helminth immunity and contributed to induced intestinal inflammation. Protein O-GlcNAcylation can be harnessed for future treatment of type 2 inflammation-associated human diseases.
Asunto(s)
Alarminas , Mucosa Intestinal , Acilación , Alarminas/inmunología , Antihelmínticos/inmunología , Biomarcadores de Tumor , Citocinas , Proteínas de Unión al ADN , Helmintiasis/inmunología , Humanos , Hiperplasia , Inflamación , Interleucina-33 , Mucosa Intestinal/inmunología , Mebendazol , N-Acetilglucosaminiltransferasas/inmunología , Proteínas Citotóxicas Formadoras de Poros , Factor de Transcripción STAT6/inmunologíaRESUMEN
Adaptive CD4+ T helper cells and their innate counterparts, innate lymphoid cells, utilize an identical set of transcription factors (TFs) for their differentiation and functions. However, similarities and differences in the induction of these TFs in related lymphocytes are still elusive. Here, we show that T helper-1 (Th1) cells and natural killer (NK) cells displayed distinct epigenomes at the Tbx21 locus, which encodes T-bet, a critical TF for regulating type 1 immune responses. The initial induction of T-bet in NK precursors was dependent on the NK-specific DNase I hypersensitive site Tbx21-CNS-3, and the expression of the interleukin-18 (IL-18) receptor; IL-18 induced T-bet expression through the transcription factor RUNX3, which bound to Tbx21-CNS-3. By contrast, signal transducer and activator of transcription (STAT)-binding motifs within Tbx21-CNS-12 were critical for IL-12-induced T-bet expression during Th1 cell differentiation both in vitro and in vivo. Thus, type 1 innate and adaptive lymphocytes utilize distinct enhancer elements for their development and differentiation.
Asunto(s)
Inmunidad Innata , Interleucina-18 , Células Asesinas Naturales , Células TH1 , Diferenciación Celular , Interleucina-18/metabolismo , Células Asesinas Naturales/inmunología , Proteínas de Dominio T Box/metabolismo , Células TH1/inmunología , Factores de Transcripción/metabolismoRESUMEN
The association between cancer and autoimmune disease is unexplained, exemplified by T cell large granular lymphocytic leukemia (T-LGL) where gain-of-function (GOF) somatic STAT3 mutations correlate with co-existing autoimmunity. To investigate whether these mutations are the cause or consequence of CD8+ T cell clonal expansions and autoimmunity, we analyzed patients and mice with germline STAT3 GOF mutations. STAT3 GOF mutations drove the accumulation of effector CD8+ T cell clones highly expressing NKG2D, the receptor for stress-induced MHC-class-I-related molecules. This subset also expressed genes for granzymes, perforin, interferon-γ, and Ccl5/Rantes and required NKG2D and the IL-15/IL-2 receptor IL2RB for maximal accumulation. Leukocyte-restricted STAT3 GOF was sufficient and CD8+ T cells were essential for lethal pathology in mice. These results demonstrate that STAT3 GOF mutations cause effector CD8+ T cell oligoclonal accumulation and that these rogue cells contribute to autoimmune pathology, supporting the hypothesis that somatic mutations in leukemia/lymphoma driver genes contribute to autoimmune disease.
Asunto(s)
Enfermedades Autoinmunes , Leucemia Linfocítica Granular Grande , Animales , Ratones , Enfermedades Autoinmunes/genética , Enfermedades Autoinmunes/patología , Linfocitos T CD8-positivos , Mutación con Ganancia de Función , Leucemia Linfocítica Granular Grande/genética , Leucemia Linfocítica Granular Grande/patología , Mutación , Subfamilia K de Receptores Similares a Lectina de Células NK/genética , Factor de Transcripción STAT3/genética , Factor de Transcripción STAT3/metabolismoRESUMEN
Prior exposure to microenvironmental signals could fundamentally change the response of macrophages to subsequent stimuli. It is believed that T helper-2 (Th2)-cell-type cytokine interleukin-4 (IL-4) and Toll-like receptor (TLR) ligand-activated transcriptional programs mutually antagonize each other, and no remarkable convergence has been identified between them. In contrast, here, we show that IL-4-polarized macrophages established a hyperinflammatory gene expression program upon lipopolysaccharide (LPS) exposure. This phenomenon, which we termed extended synergy, was supported by IL-4-directed epigenomic remodeling, LPS-activated NF-κB-p65 cistrome expansion, and increased enhancer activity. The EGR2 transcription factor contributed to the extended synergy in a macrophage-subtype-specific manner. Consequently, the previously alternatively polarized macrophages produced increased amounts of immune-modulatory factors both in vitro and in vivo in a murine Th2 cell-type airway inflammation model upon LPS exposure. Our findings establish that IL-4-induced epigenetic reprogramming is responsible for the development of inflammatory hyperresponsiveness to TLR activation and contributes to lung pathologies.
Asunto(s)
Interleucina-4 , Lipopolisacáridos , Ratones , Animales , Interleucina-4/metabolismo , Lipopolisacáridos/metabolismo , Ligandos , Epigenómica , Macrófagos/metabolismo , Receptores Toll-Like/metabolismo , Epigénesis Genética , FN-kappa B/metabolismoRESUMEN
Aged skin heals wounds poorly, increasing susceptibility to infections. Restoring homeostasis after wounding requires the coordinated actions of epidermal and immune cells. Here we find that both intrinsic defects and communication with immune cells are impaired in aged keratinocytes, diminishing their efficiency in restoring the skin barrier after wounding. At the wound-edge, aged keratinocytes display reduced proliferation and migration. They also exhibit a dampened ability to transcriptionally activate epithelial-immune crosstalk regulators, including a failure to properly activate/maintain dendritic epithelial T cells (DETCs), which promote re-epithelialization following injury. Probing mechanism, we find that aged keratinocytes near the wound edge don't efficiently upregulate Skints or activate STAT3. Notably, when epidermal Stat3, Skints, or DETCs are silenced in young skin, re-epithelialization following wounding is perturbed. These findings underscore epithelial-immune crosstalk perturbations in general, and Skints in particular, as critical mediators in the age-related decline in wound-repair.
Asunto(s)
Envejecimiento/fisiología , Subgrupos Linfocitarios/citología , Transducción de Señal , Cicatrización de Heridas , Animales , Interleucina-6/administración & dosificación , Queratinocitos/metabolismo , Ratones , Piel/citología , Fenómenos Fisiológicos de la Piel , Cicatrización de Heridas/efectos de los fármacosRESUMEN
Interleukin-22 (IL-22) acts on epithelial cells to promote tissue protection and regeneration, but can also elicit pro-inflammatory effects, contributing to disease pathology. Here, we engineered a high-affinity IL-22 super-agonist that enabled the structure determination of the IL-22-IL-22Rα-IL-10Rß ternary complex to a resolution of 2.6 Å. Using structure-based design, we systematically destabilized the IL-22-IL-10Rß binding interface to create partial agonist analogs that decoupled downstream STAT1 and STAT3 signaling. The extent of STAT bias elicited by a single ligand varied across tissues, ranging from full STAT3-biased agonism to STAT1/3 antagonism, correlating with IL-10Rß expression levels. In vivo, this tissue-selective signaling drove tissue protection in the pancreas and gastrointestinal tract without inducing local or systemic inflammation, thereby uncoupling these opposing effects of IL-22 signaling. Our findings provide insight into the mechanisms underlying the cytokine pleiotropy and illustrate how differential receptor expression levels and STAT response thresholds can be synthetically exploited to endow pleiotropic cytokines with enhanced functional specificity.
Asunto(s)
Inflamación/metabolismo , Interleucinas/metabolismo , Animales , Sitios de Unión/fisiología , Línea Celular , Línea Celular Tumoral , Citocinas/metabolismo , Femenino , Células HEK293 , Células HT29 , Células Hep G2 , Humanos , Ratones Endogámicos C57BL , Unión Proteica/fisiología , Transducción de Señal/fisiología , Interleucina-22RESUMEN
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.