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Alopecia Areata , Antígenos CD19 , Linfocitos B Reguladores , Antígeno CD24 , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven , ADP-Ribosil Ciclasa 1/metabolismo , ADP-Ribosil Ciclasa 1/inmunología , Alopecia Areata/inmunología , Antígenos CD19/inmunología , Antígenos CD19/metabolismo , Linfocitos B Reguladores/inmunología , Antígeno CD24/metabolismo , Antígeno CD24/inmunología , Glicoproteínas de MembranaRESUMEN
Cancers associated with the oncogenic gammaherpesviruses, Epstein-Barr virus and Kaposi sarcoma herpesvirus, are notable for their constitutive activation of the transcription factor signal transducer and activator of transcription 3 (STAT3). To better understand the role of STAT3 during gammaherpesvirus latency and the B cell response to infection, we used the model pathogen murine gammaherpesvirus 68 (MHV68). Genetic deletion of STAT3 in B cells of CD19cre/+Stat3f/f mice reduced peak MHV68 latency approximately sevenfold. However, infected CD19cre/+Stat3f/f mice exhibited disordered germinal centers and heightened virus-specific CD8 T cell responses compared to wild-type (WT) littermates. To circumvent the systemic immune alterations observed in the B cell-STAT3 knockout mice and more directly evaluate intrinsic roles for STAT3, we generated mixed bone marrow chimeric mice consisting of WT and STAT3 knockout B cells. We discovered a dramatic reduction in latency in STAT3 knockout B cells compared to their WT B cell counterparts in the same lymphoid organ. RNA sequencing of sorted germinal center B cells revealed that MHV68 infection shifts the gene signature toward proliferation and away from type I and type II IFN responses. Loss of STAT3 largely reversed the virus-driven transcriptional shift without impacting the viral gene expression program. STAT3 promoted B cell processes of the germinal center, including IL-21-stimulated downregulation of surface CD23 on B cells infected with MHV68 or EBV. Together, our data provide mechanistic insights into the role of STAT3 as a latency determinant in B cells for oncogenic gammaherpesviruses.IMPORTANCEThere are no directed therapies to the latency program of the human gammaherpesviruses, Epstein-Barr virus and Kaposi sarcoma herpesvirus. Activated host factor signal transducer and activator of transcription 3 (STAT3) is a hallmark of cancers caused by these viruses. We applied the murine gammaherpesvirus pathogen system to explore STAT3 function upon primary B cell infection in the host. Since STAT3 deletion in all CD19+ B cells of infected mice led to altered B and T cell responses, we generated chimeric mice with both normal and STAT3-deleted B cells. B cells lacking STAT3 failed to support virus latency compared to normal B cells from the same infected animal. Loss of STAT3 impaired B cell proliferation and differentiation and led to a striking upregulation of interferon-stimulated genes. These findings expand our understanding of STAT3-dependent processes that are key to its function as a pro-viral latency determinant for oncogenic gammaherpesviruses in B cells and may provide novel therapeutic targets.
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Infecciones por Virus de Epstein-Barr , Gammaherpesvirinae , Infecciones por Herpesviridae , Herpesvirus Humano 8 , Rhadinovirus , Sarcoma de Kaposi , Animales , Humanos , Ratones , Gammaherpesvirinae/genética , Herpesvirus Humano 4/genética , Herpesvirus Humano 4/metabolismo , Herpesvirus Humano 8/metabolismo , Ratones Endogámicos C57BL , Rhadinovirus/genética , Factor de Transcripción STAT3/genética , Factor de Transcripción STAT3/metabolismo , Latencia del Virus/genéticaRESUMEN
In recent years, with the in-depth research on the pathogenesis of vitiligo, the Janus kinase (JAK) -signal transducer and activator of transcription (STAT) pathway has attracted more and more attention. This review summarizes the role of the JAK-STAT signaling pathway in the development of vitiligo, as well as JAK-STAT inhibitors that are currently being studied or have been used in the treatment of vitiligo.
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OBJECTIVE: To investiage the possible mechanism underlying the effect of the Jianpi Qutan Fang (, JPQT) on Atherosclerosis (AS) which is the main pathological process of most cardiovascular diseases that affect millions of adults worldwide. METHODS: In the present study, rats were fed with a high-fat-diet (HFD) with vitamin D3 for 16 weeks and were orally administered atorvastatin treatment and different doses of JPQT. Histopathological changes and ultrastructural changes in the aorta were evaluated through hematoxylin-eosin staining and transmission electron microscopy (TEM), respectively. Suppressor of cytokine signaling 1 (SOCS1)/Janus kinase 1 (JAK1)/ signal transducer and activator of transcription 1 (STAT1) signaling pathways were detected through Western blotting. RESULTS: JPQT treatment decreased the lipid levels of triglyceride, low-density lipoprotein, and cholesterol, the inflammatory cytokine levels of interleukin 1 beta (IL-1ß), IL-6 and IL-8 in rat serum, but increased high-density lipoprotein and IL-10 serum levels. JPQT treatment ameliorated pathological changes in the aorta of AS model rats. Moreover, JPQT upregulated SOCS1 protein expression and down-regulated phosphorylated protein expression levels of p-JAK1 and p-STAT1. CONCLUSION: These results suggest that JPQT induces anti-atherosclerosis effects through anti-inflammatory and inhibiting JAK/STAT signaling pathways in HFD fed rats.
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Aterosclerosis , Quinasas Janus , Ratas , Animales , Quinasas Janus/genética , Quinasas Janus/metabolismo , Dieta Alta en Grasa/efectos adversos , Transducción de Señal , Citocinas/genética , Citocinas/metabolismo , Aterosclerosis/tratamiento farmacológico , Aterosclerosis/genética , Células Endoteliales/metabolismo , Antiinflamatorios/farmacología , Factor de Transcripción STAT3/genética , Factor de Transcripción STAT3/metabolismoRESUMEN
Objective:To determine the change in the expression of tumor necrosis factor receptor-associated factor 6 (TRAF6) in lung tissues of rats with pulmonary hypertension (PH).Methods:Sixteen SPF-grade healthy male Sprague-Dawley rats, aged 8 weeks, weighing 200-220 g, were divided into 2 groups ( n=8 each) by the random number table method: control group (group C1) and PH group (group PH1). The model of PH was prepared by subcutaneous injection of monocrotaline. On day 28 after developing the model, the mean pulmonary arterial pressure (mPAP) was measured, and the Fulton index was calculated, and the percentage of media wall thickness of the small and medium pulmonary arteries and percentage of muscularized vessels were also calculated. The expression of TRAF6, transcription-3 (STAT3), phosphorylated STAT3 (p-STAT3) and Cyclin D1 in lung tissues was detected by Western blot, and p-STAT3/STAT3 ratio was calculated. The interaction between TRAF6 and STAT3 was determined by immunoprecipitation assay. Primarily cultured pulmonary artery smooth muscle cells of normal rats (group C2) and pulmonary artery smooth muscle cells of rats with PH (group PH2) were inoculated in 6-well plates ( n=3 each). The expression of TRAF6 mRNA was detected by quantitative polymerase chain reaction. The expression of TRAF6, STAT3, p-STAT3 and Cyclin D1 was detected by Western blot. Results:Compared with group C1, the mPAP, Fulton index, percentage of media wall thickness of the small and medium pulmonary arteries and percentage of muscularized vessels were significantly increased, the expression of TRAF6 and Cyclin D1 in lung tissues was up-regulated, the p-STAT3/STAT3 ratio was increased ( P<0.05 or 0.01), and the results of immunoprecipitation showed that TRAF6 interacted with STAT3 in group PH1. Compared with group C2, the expression of TRAF6 protein and mRNA and Cyclin D1 was significantly up-regulated, and the p-STAT3/STAT3 ratio was increased in group PH2 ( P<0.05 or 0.01). Conclusions:The expression of TRAF6 in the lung tissue is up-regulated in rats with PH, which may be related to pulmonary vascular remodeling by promoting the activation of STAT3.
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The Janus kinase (JAK) -signal transducer and activator of transcription (STAT) signaling pathway is closely related to the occurrence of psoriasis. Various cytokines, including interleukin (IL) -23, IL-22, interferon (IFN) -γ, etc., can promote some key pathologic processes (such as the proliferation and abnormal differentiation of keratinocytes, and infiltration of inflammatory cells) via the JAK-STAT pathway in psoriasis, which suggests that targeting JAK-STAT pathway is a new strategy for the treatment of psoriasis. In recent years, small-molecule JAK inhibitors have shown good efficacy and safety in the treatment of psoriasis, and drugs targeting STAT pathway have been under development, which provide more treatment options for psoriasis. This review summarizes progress in drugs targeting the JAK-STAT signaling pathway in the treatment of psoriasis.
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Background: Colorectal cancer (CRC) is the third most prevalent cancer worldwide and the second leading cause of cancer mortality. Signal transducer and activator of transcription (STAT) proteins are a group of transcription factors implicated in cell signal transduction and gene transcription in several cancer types. However, the level of expression, genetic alterations, and biological function of different STATs, as well as their prognostic and immunotherapeutic value in CRC remain unclear. Methods: The mRNA and protein expression levels, genetic alterations, prognostic value, gene-gene and protein-protein interaction networks, and biological function of STATs in CRC were studied using the GEPIA, HPA, cBioPortal, PrognoScan, Kaplan-Meier plotter, GeneMANIA, STRING, and Metascape databases. The expression of STATs in CRC was confirmed using immunohistochemistry (IHC). Finally, the relationship between STAT expression and immune infiltration as well as immunotherapy-associated indicators was also investigated. Results: The expression levels of STAT2/5A/5B are downregulated in CRC, and the STAT1/3/4/5B expressions were significantly associated with the tumor stage of patients with CRC. The abnormal expression of STAT2/4/5B in patients with CRC is related to the prognosis of patients with CRC. The STATs and their neighboring proteins are primarily associated with lymphocyte activation, cytokine-mediated signaling pathways, positive regulation of immune response, regulation of cytokine production, and growth hormone receptor signaling pathways in cancer. The expression of STATs was significantly associated with immune infiltration and immunotherapy response-associated indicators. Conclusion: This study may help further understand the molecular mechanism of CRC and provide new prognostic biomarkers and immunotherapy targets in patients with CRC.
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The coronavirus disease 2019 (COVID-19) pandemic constitutes a global health emergency. Currently, there are no completely effective therapeutic medications for the management of this outbreak. The cytokine storm is a hyperinflammatory medical condition due to excessive and uncontrolled release of pro-inflammatory cytokines in patients suffering from severe COVID-19, leading to the development of acute respiratory distress syndrome (ARDS) and multiple organ dysfunction syndrome (MODS) and even mortality. Understanding the pathophysiology of COVID-19 can be helpful for the treatment of patients. Evidence suggests that the levels of tumor necrosis factor alpha (TNF-α) and interleukin (IL)-1 and IL-6 are dramatically different between mild and severe patients, so they may be important contributors to the cytokine storm. Several serum markers can be predictors for the cytokine storm. This review discusses the cytokines involved in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, focusing on interferons (IFNs) and ILs, and whether they can be used in COVID-19 treatment. Moreover, we highlight several microRNAs that are involved in these cytokines and their role in the cytokine storm caused by COVID-19.
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Unravelling the molecular mechanisms that account for functional pleiotropy is a major challenge for researchers in cytokine biology. Cytokine-receptor cross-reactivity and shared signalling pathways are considered primary drivers of cytokine pleiotropy. However, reports epitomized by studies of Jak-STAT cytokine signalling identify interesting biochemical and epigenetic determinants of transcription factor regulation that affect the delivery of signal-dependent cytokine responses. Here, a regulatory interplay between STAT transcription factors and their convergence to specific genomic enhancers support the fine-tuning of cytokine responses controlling host immunity, functional identity, and tissue homeostasis and repair. In this review, we provide an overview of the signalling networks that shape the way cells sense and interpret cytokine cues. With an emphasis on the biology of interleukin-6, we highlight the importance of these mechanisms to both physiological processes and pathophysiological outcomes.
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Señales (Psicología) , Interleucina-6 , Citocinas/metabolismo , Interleucina-6/metabolismo , Quinasas Janus/genética , Factores de Transcripción STAT/genética , Factores de Transcripción STAT/metabolismo , Transducción de SeñalRESUMEN
IL-1ß plays critical roles in the priming and effector phases of immune responses such as the differentiation, commitment, and memory formation of T cells. In this context, several reports have suggested that the IL-1ß signal is crucial for CTL-mediated immune responses to viral infections and tumors. However, little is known regarding whether IL-1ß acts directly on CD8+ T cells and what the molecular mechanisms underlying expression of IL-1 receptors (IL-1Rs) on CD8+ T cells and features of IL-1R+CD8+ T cells are. Here, we provide evidence that the expression of IL-1R type I (IL-1RI), the functional receptor of IL-1ß, is preferentially induced by IL-21 on TCR-stimulated CD8+ T cells. Further, IL-1ß enhances the effector function of CD8+ T cells expressing IL-21-induced IL-1RI by increasing cytokine production and release of cytotoxic granules containing granzyme B. The IL-21-IL-1RI-IL-1ß axis is involved in an augmented effector function through regulation of transcription factors BATF, Blimp-1, and IRF4. Moreover, this axis confers a unique effector function to CD8+ T cells compared to conventional type 1 cytotoxic T cells differentiated with IL-12. Chemical inhibitor and immunoprecipitation assay demonstrated that IL-21 induces a unique pattern of STAT activation with the formation of both STAT1:STAT3 and STAT3:STAT5 heterodimers, which are critical for the induction of IL-1RI on TCR-stimulated CD8+ T cells. Taken together, we propose that induction of a novel subset of IL-1RI-expressing CD8+ T cells by IL-21 may be beneficial to the protective immune response against viral infections and is therefore important to consider for vaccine design.
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Transforming growth factor beta (TGF-ß) plays key roles in regulating cellular proliferation and maintaining tissue homeostasis. TGF-ß exerts tumor-suppressive effects in the early stages of carcinogenesis, but it also plays tumor-promoting roles in established tumors. Additionally, it plays a critical role in cancer radiotherapy. TGF-ß expression or activation increases in irradiated tissues, and studies have shown that TGF-ß plays dual roles in cancer radiosensitivity and is involved in ionizing radiation-induced fibrosis in different tumor microenvironments (TMEs). Furthermore, TGF-ß promotes radioresistance by inducing the epithelial-mesenchymal transition (EMT), cancer stem cells (CSCs) and cancer-associated fibroblasts (CAFs), suppresses the immune system and facilitates cancer resistance. In particular, the links between TGF-ß and the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) axis play a critical role in cancer therapeutic resistance. Growing evidence has shown that TGF-ß acts as a radiation protection agent, leading to heightened interest in using TGF-ß as a therapeutic target. The future of anti-TGF-ß signaling therapy for numerous diseases appears bright, and the outlook for the use of TGF-ß inhibitors in cancer radiotherapy as TME-targeting agents is promising.
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Neoplasias/metabolismo , Neoplasias/radioterapia , Transducción de Señal , Factor de Crecimiento Transformador beta/metabolismo , Resistencia a Antineoplásicos , Fibrosis , Humanos , Modelos Biológicos , Neoplasias/inmunología , Neoplasias/patologíaRESUMEN
Septic shock and disseminated intravascular coagulation (DIC) are known to be characterized by an endothelial cell dysfunction. The molecular mechanisms underlying this relationship are, however, poorly understood. In this work, we aimed to investigate human circulating IFN-α in patients with septic shock-induced DIC and tested the potential role of endothelial Stat1 (signal transducer and activator of transcription 1) as a therapeutic target in a mouse model of sepsis. For this, circulating type I, type II, and type III IFNs and procoagulant microvesicles were quantified in a prospective cohort of patients with septic shock. Next, we used a septic shock model induced by cecal ligation and puncture in wild-type mice, in Ifnar1 (type I IFN receptor subunit 1)-knockout mice, and in Stat1 conditional knockout mice. In human samples, we observed higher concentrations of circulating IFN-α and IFN-α1 in patients with DIC compared with patients without DIC, whereas concentrations of IFN-ß, IFN-γ, IFN-λ1, IFN-λ2, and IFN-λ3 were not different. IFN-α concentration was positively correlated with CD105 microvesicle concentrations, reflecting endothelial injury. In Ifnar1-/- mice, cecal ligation and puncture did not induce septic shock and was characterized by lesser endothelial cell injury, with lower aortic inflammatory cytokine expression, endothelial inflammatory-related gene expression, and fibrinolysis. In mice in which Stat1 was specifically ablated in endothelial cells, a marked protection against sepsis was also observed, suggesting the relevance of an endothelium-targeted strategy. Our work highlights the key roles of type I IFNs as pathogenic players in septic shock-induced DIC and the potential pertinence of endothelial STAT1 as a therapeutic target.
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Coagulación Intravascular Diseminada/metabolismo , Interferón-alfa/metabolismo , Factor de Transcripción STAT1/metabolismo , Choque Séptico/metabolismo , Transducción de Señal , Anciano , Animales , Coagulación Intravascular Diseminada/genética , Femenino , Humanos , Interferón-alfa/genética , Masculino , Ratones , Ratones Noqueados , Persona de Mediana Edad , Factor de Transcripción STAT1/genética , Choque Séptico/genética , Choque Séptico/terapiaRESUMEN
Polymorphic effector proteins determine the susceptibility of Toxoplasma gondii strains to IFN-γ-mediated clearance mechanisms deployed by murine host cells. However, less is known about the influence of these polymorphic effector proteins on IFN-γ-independent clearance mechanisms. Here, we show that deletion of one such polymorphic effector protein, ROP16, from a type III background leads to a defect in parasite growth and survival in unstimulated human fibroblasts and murine macrophages. Rescue of these defects requires a ROP16 with a functional kinase domain and the ability to activate a specific family of host cell transcription factors (STAT3, 5a, and 6). The growth and survival defects correlate with an accumulation of host cell reactive oxygen species (ROS) and are prevented by treatment with an ROS inhibitor. Exogenous activation of STAT3 and 6 suppresses host cell ROS production during infection with ROP16-deficient parasites and depletion of STAT6, but not STAT3 or 5a, causes an accumulation of ROS in cells infected with wild-type parasites. Pharmacological inhibition of NOX2 and mitochondrially derived ROS also rescues growth and survival of ROP16-deficient parasites. Collectively, these findings reveal an IFN-γ-independent mechanism of parasite restriction in human cells that is subverted by injection of ROP16 by type III parasites.IMPORTANCEToxoplasma gondii is an obligate intracellular parasite that infects up to one-third of the world's population. Control of the parasite is largely accomplished by IFN-γ-dependent mechanisms that stimulate innate and adaptive immune responses. Parasite suppression of IFN-γ-stimulated responses has been linked to proteins that the parasite secretes into its host cell. These secreted proteins vary by T. gondii strain and determine strain-specific lethality in mice. How these strain-specific polymorphic effector proteins affect IFN-γ-independent parasite control mechanisms in human and murine cells is not well known. This study shows that one such secreted protein, ROP16, enables efficient parasite growth and survival by suppressing IFN-γ-independent production of ROS by human and mouse cells.
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Interacciones Huésped-Parásitos , Proteínas Tirosina Quinasas/genética , Proteínas Protozoarias/genética , Especies Reactivas de Oxígeno/antagonistas & inhibidores , Factor de Transcripción STAT6/genética , Toxoplasma/crecimiento & desarrollo , Toxoplasma/genética , Animales , Línea Celular , Fibroblastos/parasitología , Humanos , Inmunidad Innata , Macrófagos , Ratones , Proteínas Tirosina Quinasas/metabolismo , Proteínas Protozoarias/metabolismo , Factor de Transcripción STAT6/metabolismo , Células THP-1 , Toxoplasma/inmunología , Toxoplasma/fisiologíaRESUMEN
INTRODUCTION: To explore the involvement of signal transducers and activators of transcription (STATs) in trophoblast differentiation. METHODS AND RESULTS: First, the localization of STATs in human placentas was detected via immunohistochemistry (IHC) and immunofluorescence (IF). Cytotrophoblasts (CTBs) expressed both STAT1 and 3, but syncytiotrophoblasts (STBs) did not. Staining for these two proteins showed a distinct upregulation from the proximal part to the distal end of cell columns. STAT5B was mainly expressed in the STBs, low in the CTBs, and absent in the extravillous trophoblasts (EVTs). Next, the 44 placenta samples were tested via western blot (WB) and quantitative real time polymerase chain reaction (qRT-PCR). We found a decrease in STAT1 and 3 and an increase in STAT5B as gestation increased from five to 10 weeks. Then, an in vitro co-culture model of placenta with or without decidua stromal cells (DSCs), as detected via flow cytometry, revealed an increase in the human leukocyte antigen (HLA)-G positive rate in trophoblasts from placentas co-cultured with DSCs, accompanied by an increase in p-STAT1 and 3 and a decrease in p-STAT5 and STAT5B. Finally, mRNA of matrix metalloproteinases (MMPs) and integrins after STAT silencing in HTR-8/SVneo was detected via qRT-PCR. STAT1 silencing decreased MMP9 expression, STAT3 silencing decreased MMP9, integrin α6, and ß4 expression, and STAT5B silencing increased MMP2 and integrin ß1 expression. DISCUSSION: Different trophoblasts showed distinct STAT expression profiles which were related to their MMP and integrin expression. DSCs promoted trophoblast differentiation into EVTs, possibly by regulating the STAT expression of the trophoblasts.
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Diferenciación Celular/fisiología , Placenta/metabolismo , Factores de Transcripción STAT/metabolismo , Trofoblastos/metabolismo , Adulto , Línea Celular , Femenino , Humanos , Metaloproteinasas de la Matriz/genética , Metaloproteinasas de la Matriz/metabolismo , Placenta/citología , Embarazo , Factores de Transcripción STAT/genética , Células del Estroma/citología , Células del Estroma/metabolismo , Trofoblastos/citología , Adulto JovenRESUMEN
The Nipah virus (NiV) phosphoprotein (P) gene encodes four proteins. Three of these-P, V, and W-possess a common N-terminal domain but distinct C termini. These proteins interact with immune modulators. Previous studies demonstrated that P, V, and W bind STAT1 and STAT4 and that V also interacts with STAT2 but not with STAT3. The STAT1 and STAT2 interactions block interferon (IFN)-induced STAT tyrosine phosphorylation. To more fully characterize the interactions of P, V, and W with the STATs, we screened for interaction of each viral protein with STATs 1 to 6 by coimmunoprecipitation. We demonstrate that NiV P, V, and W interact with STAT4 through their common N-terminal domain and block STAT4 activity, based on a STAT4 response element reporter assay. Although none of the NiV proteins interact with STAT3 or STAT6, NiV V, but not P or W, interacts with STAT5 through its unique C terminus. Furthermore, the interaction of NiV V with STAT5 was not disrupted by overexpression of the N-terminal binding STAT1 or the C-terminal binding MDA5. NiV V also inhibits a STAT5 response element reporter assay. Residues 114 to 140 of the common N-terminal domain of the NiV P gene products were found to be sufficient to bind STAT1 and STAT4. Analysis of STAT1-STAT3 chimeras suggests that the P gene products target the STAT1 SH2 domain. When fused to GST, the 114-140 peptide is sufficient to decrease STAT1 phosphorylation in IFN-ß-stimulated cells, suggesting that this peptide could potentially be fused to heterologous proteins to confer inhibition of STAT1- and STAT4-dependent responses.IMPORTANCE How Nipah virus (NiV) antagonizes innate immune responses is incompletely understood. The P gene of NiV encodes the P, V, and W proteins. These proteins have a common N-terminal sequence that is sufficient to bind to STAT1 and STAT2 and block IFN-induced signal transduction. This study sought to more fully understand how P, V, and W engage with the STAT family of transcription factors to influence their functions. The results identify a novel interaction of V with STAT5 and demonstrate V inhibition of STAT5 function. We also demonstrate that the common N-terminal residues 114 to 140 of P, V, and W are critical for inhibition of STAT1 and STAT4 function, map the interaction to the SH2 region of STAT1, and show that a fusion construct with this peptide significantly inhibits cytokine-induced STAT1 phosphorylation. These data clarify how these important virulence factors modulate innate antiviral defenses.
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Núcleo Celular/química , Infecciones por Henipavirus/metabolismo , Virus Nipah/fisiología , Factores de Transcripción STAT/metabolismo , Proteínas Virales/metabolismo , Células HEK293 , Infecciones por Henipavirus/inmunología , Infecciones por Henipavirus/virología , Humanos , Inmunidad Innata/inmunología , Fosforilación , Factores de Transcripción STAT/genética , Transducción de Señal , Transactivadores/metabolismo , Proteínas Virales/genéticaRESUMEN
Viruses commonly antagonize the antiviral type I interferon response by targeting signal transducer and activator of transcription 1 (STAT1) and STAT2, key mediators of interferon signaling. Other STAT family members mediate signaling by diverse cytokines important to infection, but their relationship with viruses is more complex. Importantly, virus-STAT interaction can be antagonistic or stimulatory depending on diverse viral and cellular factors. While STAT antagonism can suppress immune pathways, many viruses promote activation of specific STATs to support viral gene expression and/or produce cellular conditions conducive to infection. It is also becoming increasingly clear that viruses can hijack noncanonical STAT functions to benefit infection. For a number of viruses, STAT function is dynamically modulated through infection as requirements for replication change. Given the critical role of STATs in infection by diverse viruses, the virus-STAT interface is an attractive target for the development of antivirals and live-attenuated viral vaccines. Here, we review current understanding of the complex and dynamic virus-STAT interface and discuss how this relationship might be harnessed for medical applications.
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Factores de Transcripción STAT/metabolismo , Transducción de Señal/fisiología , Virus/metabolismo , Citocinas , Expresión Génica , Interacciones Huésped-Patógeno , Evasión Inmune , Factores de Transcripción STAT/genética , Factor de Transcripción STAT1/metabolismo , Factor de Transcripción STAT2/metabolismo , Factor de Transcripción STAT4 , Factor de Transcripción STAT6 , Virus/genéticaRESUMEN
Measles virus (MeV) is a highly immunotropic and contagious pathogen that can even diminish preexisting antibodies and remains a major cause of childhood morbidity and mortality worldwide despite the availability of effective vaccines. MeV is one of the most extensively studied viruses with respect to the mechanisms of JAK-STAT antagonism. Of the three proteins translated from the MeV P gene, P and V are essential for inactivation of this pathway. However, the lack of data from direct analyses of the underlying interactions means that the detailed molecular mechanism of antagonism remains unresolved. Here, we prepared recombinant MeV V protein, which is responsible for human JAK-STAT antagonism, and a panel of variants, enabling the biophysical characterization of V protein, including direct V/STAT1 and V/STAT2 interaction assays. Unambiguous direct interactions between the host and viral factors, in the absence of other factors such as Jak1 or Tyk2, were observed, and the dissociation constants were quantified for the first time. Our data indicate that interactions between the C-terminal region of V and STAT2 is 1 order of magnitude stronger than that of the N-terminal region of V and STAT1. We also clarified that these interactions are completely independent of each other. Moreover, results of size exclusion chromatography demonstrated that addition of MeV-V displaces STAT2-core, a rigid region of STAT2 lacking the N- and C-terminal domains, from preformed complexes of STAT2-core/IRF-associated domain (IRF9). These results provide a novel model whereby MeV-V can not only inhibit the STAT2/IRF9 interaction but also disrupt preassembled interferon-stimulated gene factor 3.IMPORTANCE To evade host immunity, many pathogenic viruses inactivate host Janus kinase signal transducer and activator of transcription (STAT) signaling pathways using diverse strategies. Measles virus utilizes P and V proteins to counteract this signaling pathway. Data derived largely from cell-based assays have indicated several amino acid residues of P and V proteins as important. However, biophysical properties of V protein or its direct interaction with STAT molecules using purified proteins have not been studied. We have developed novel molecular tools enabling us to identify a novel molecular mechanism for immune evasion whereby V protein disrupts critical immune complexes, providing a clear strategy by which measles virus can suppress interferon-mediated antiviral gene expression.
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Subunidad gamma del Factor 3 de Genes Estimulados por el Interferón/química , Virus del Sarampión/metabolismo , Fosfoproteínas/química , Factor de Transcripción STAT2/química , Proteínas Virales/química , Sitios de Unión , Expresión Génica , Humanos , Evasión Inmune , Inmunidad Innata , Subunidad gamma del Factor 3 de Genes Estimulados por el Interferón/genética , Subunidad gamma del Factor 3 de Genes Estimulados por el Interferón/metabolismo , Quinasas Janus/metabolismo , Virus del Sarampión/genética , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Unión Proteica , Dominios Proteicos , Dominios y Motivos de Interacción de Proteínas , Factor de Transcripción STAT1/química , Factor de Transcripción STAT1/genética , Factor de Transcripción STAT1/metabolismo , Factor de Transcripción STAT2/genética , Factor de Transcripción STAT2/metabolismo , Transducción de Señal , Proteínas Virales/genética , Proteínas Virales/metabolismo , Dedos de ZincRESUMEN
Oncogene-induced STAT3-activation is central to tumor progression by promoting cancer cell expression of pro-angiogenic and immunosuppressive factors. STAT3 is also activated in infiltrating immune cells including tumor-associated macrophages (TAM) amplifying immune suppression. Consequently, STAT3 is considered as a target for cancer therapy. However, its interplay with other STAT-family members or transcription factors such as NF-κB has to be considered in light of their concerted regulation of immune-related genes. Here, we discuss new attempts at re-educating immune suppressive tumor-associated macrophages towards a CD8 T cell supporting profile, with an emphasis on the role of STAT transcription factors on TAM functional programs. Recent clinical trials using JAK/STAT inhibitors highlighted the negative effects of these molecules on the maintenance and function of effector/memory T cells. Concerted regulation of STAT3 and STAT5 activation in CD8 T effector and memory cells has been shown to impact their tumor-specific responses including intra-tumor accumulation, long-term survival, cytotoxic activity and resistance toward tumor-derived immune suppression. Interestingly, as an escape mechanism, melanoma cells were reported to impede STAT5 nuclear translocation in both CD8 T cells and NK cells. Ours and others results will be discussed in the perspective of new developments in engineered T cell-based adoptive therapies to treat cancer patients.
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The JAK-STAT pathway is an important physiologic regulator of different cellular functions including proliferation, apoptosis, differentiation, and immunological responses. Out of six different STAT proteins, STAT5 plays its main role in hematopoiesis and constitutive STAT5 activation seems to be a key event in the pathogenesis of several hematological malignancies. This has led many researchers to develop compounds capable of inhibiting STAT5 activation or interfering with its functions. Several anti-STAT5 molecules have shown potent STAT5 inhibitory activity in vitro. However, compared to the large amount of clinical studies with JAK inhibitors that are currently widely used in the clinics to treat myeloproliferative disorders, the clinical trials with STAT5 inhibitors are very limited. At present, a few STAT5 inhibitors are in phase I or II clinical trials for the treatment of leukemias and graft vs host disease. These studies seem to indicate that such compounds could be well tolerated and useful in reducing the occurrence of resistance to tyrosine kinase inhibitors in chronic myeloid leukemia. Of interest, STAT5 seems to play an important role in the regulation of hematopoietic stem cell self-renewal suggesting that combination therapies including STAT5 inhibitors can erode the cancer stem cell pool and possibly open the way for the complete cancer eradication. In this review, we discuss the implication of STAT5 in hematological malignancies and the results obtained with the novel STAT5 inhibitors.
Asunto(s)
Antineoplásicos/farmacología , Neoplasias Hematológicas/tratamiento farmacológico , Factor de Transcripción STAT5/antagonistas & inhibidores , Animales , Neoplasias Hematológicas/metabolismo , Humanos , Factor de Transcripción STAT5/metabolismoRESUMEN
Background: Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide. Although early diagnosis and treatment is the most successful strategy for improving patient survival, feasible and sensitive blood biomarkers for CRC screening remain elusive. Methods: Sixty-five CRC patients and thirty-three healthy individuals were enrolled. Peripheral blood (PB) and tumor tissues from CRC patients, and PB from healthy individuals were subjected to immunophenotyping and phospho-flow analysis of cytokine-induced phosphorylated STAT (CIPS). Logistic regression was used as a classifier that separates CRC patients from healthy individuals. Results: The proportion of regulatory T cells was increased in PB from CRC patients compared to PB from healthy individuals (p < 0.05). Interestingly, peripheral T cells share several cytokine-induced phosphorylated STAT (CIPS) signatures with T cells from CRC tumor-sites. Additionally, a classifier was made using two signatures distinct between T cells from CRC patients and T cells from healthy individuals. The AUCs (area under curves) of the classifier were 0.88 in initial cohort and 0.94 in the additional validation cohort. Overall AUC was 0.94 with sensitivity of 91% and specificity of 88%. Conclusion: This study highlights that immune cell signatures in peripheral blood could offer a new type of biomarker for CRC screening.