ABSTRACT
Arsenic and its inorganic compounds affect numerous organs and systemic functions, such as the nervous and hematopoietic systems, liver, kidneys, and skin. Despite a large number of studies on arsenic toxicity, rare reports have investigated the leukopenia incidence in workers exposed to arsenic. In workplaces, the main source of workers' exposure is the contaminated air by the inorganic arsenic in mines, arsenic or copper smelter industries, and chemical factories. Erythropoiesis inhibition is one of the arsenic effects and it is related to regulatory factor GATA-1. This factor is necessary for the normal differentiation of early erythroid progenitors. JAK-STAT is an important intracellular signal transduction pathway responsible for the mediating normal functions of several cytokines related to cell proliferation and hematopoietic systems development and regulation. Arsenic inactivates JAK-STAT by inhibiting JAK tyrosine kinase and using the IFNγ pathway. The intravascular hemolysis starts after the absorption phase when arsenic binds to the globin of hemoglobin in erythrocytes and is transported into the body, which increases the oxidation of sulfhydryl groups in hemoglobin. So, this article intends to highlight the potential leukopenia risk via inhalation for workers exposed to arsenic and suggests a possible mechanism for this leukopenia through the JAK-signal transducer and activator of transcription (STAT) pathway inhibition.
Subject(s)
Arsenic , Leukopenia , Occupational Exposure , Humans , Occupational Exposure/adverse effects , Arsenic/toxicity , Leukopenia/chemically induced , Signal Transduction/drug effects , STAT Transcription Factors/metabolism , Janus Kinases/metabolismABSTRACT
Interferons (IFNs) are a family of cytokines that activate the JAK-STAT signaling pathway to induce an antiviral state in cells. Interleukin 27 (IL-27) is a member of the IL-6 and/or IL-12 family that elicits both pro- and anti-inflammatory responses. Recent studies have reported that IL-27 also induces a robust antiviral response against diverse viruses, both in vitro and in vivo, suggesting that IFNs and IL-27 share many similarities at the functional level. However, it is still unknown how similar or different IFN- and IL-27-dependent signaling pathways are. To address this question, we conducted a comparative analysis of the transcriptomic profiles of human monocyte-derived macrophages (MDMs) exposed to IL-27 and those exposed to recombinant human IFN-α, IFN-γ, and IFN-λ. We utilized bioinformatics approaches to identify common differentially expressed genes between the different transcriptomes. To verify the accuracy of this approach, we used RT-qPCR, ELISA, flow cytometry, and microarrays data. We found that IFNs and IL-27 induce transcriptional changes in several genes, including those involved in JAK-STAT signaling, and induce shared pro-inflammatory and antiviral pathways in MDMs, leading to the common and unique expression of inflammatory factors and IFN-stimulated genes (ISGs)Importantly, the ability of IL-27 to induce those responses is independent of IFN induction and cellular lineage. Additionally, functional analysis demonstrated that like IFNs, IL-27-mediated response reduced chikungunya and dengue viruses replication in MDMs. In summary, IL-27 exhibits properties similar to those of all three types of human IFN, including the ability to stimulate a protective antiviral response. Given this similarity, we propose that IL-27 could be classified as a distinct type of IFN, possibly categorized as IFN-pi (IFN-π), the type V IFN (IFN-V).
Subject(s)
Chikungunya Fever , Dengue , Interleukin-27 , Janus Kinases , Macrophages , Signal Transduction , Humans , Cells, Cultured , Chikungunya Fever/immunology , Chikungunya Fever/virology , Chikungunya virus/immunology , Dengue/immunology , Dengue/virology , Dengue Virus/physiology , Dengue Virus/immunology , Interferons/metabolism , Interleukin-27/metabolism , Interleukins/immunology , Interleukins/pharmacology , Janus Kinases/metabolism , Macrophages/immunology , Macrophages/virology , Signal Transduction/genetics , STAT Transcription Factors/metabolism , Transcriptome , Virus ReplicationABSTRACT
Breast cancer remains the most frequently diagnosed cancer in women worldwide. Tumors that express hormone receptors account for 75% of all cases. Understanding alternative signaling cascades is important for finding new therapeutic targets for hormone receptor-positive breast cancer patients. JAK-STAT signaling is commonly activated in hormone receptor-positive breast tumors, inducing inflammation, proliferation, migration, and treatment resistance in cancer cells. In hormone receptor-positive breast cancer, the JAK-STAT cascade is stimulated by hormones and cytokines, such as prolactin and IL-6. In normal cells, JAK-STAT is inhibited by the action of the adaptor protein, LNK. However, the role of LNK in breast tumors is not fully understood. This review compiles published reports on the expression and activation of the JAK-STAT pathway by IL-6 and prolactin and potential inhibition of the cascade by LNK in hormone receptor-positive breast cancer. Additionally, it includes analyses of available datasets to determine the level of expression of LNK and various members of the JAK-STAT family for the purpose of establishing associations between expression and clinical outcomes. Together, experimental evidence and in silico studies provide a better understanding of the potential implications of the JAK-STAT-LNK loop in hormone receptor-positive breast cancer progression.
Subject(s)
Breast Neoplasms , Signal Transduction , Humans , Female , Signal Transduction/physiology , Janus Kinases/metabolism , Prolactin/metabolism , Interleukin-6/metabolism , STAT Transcription Factors/metabolismABSTRACT
The Krüppel-like factor 13 (KLF13) has emerged as an important transcription factor involved in essential processes of the central nervous system (CNS). It predominantly functions as a transcriptional repressor, impacting the activity of several signaling pathways with essential roles in the CNS, including the JAK/STAT pathway, which is the canonical mediator of growth hormone (GH) signaling. It is now recognized that GH has important actions as a neurotrophic factor. Therefore, we analyzed the effects of KLF13 on the activity of the JAK/STAT signaling pathway in the hippocampus-derived cell line HT22. Results showed that KLF13 directly regulates the expression of several genes involved in the JAK-STAT pathway, including Jak1, Jak2, Jak3, and Socs1, by associating with their proximal gene promoters. In addition, it was found that in KLF13-deficient HT22 neurons, the expression of Jak1, Stat3, Socs1, Socs3, and Igf1 was dysregulated, exhibiting mRNA levels that went up to 7-fold higher than the control cell line. KLF13 displayed a differential effect on the GH-induced JAK/STAT pathway activity, decreasing the STAT3 branch while enhancing the STAT5 branch. In KLF13-deficient HT22 cells, the activity of the STAT3 branch was enhanced, mediating the GH-dependent augmented expression of the JAK/STAT output genes Socs1, Socs3, Igf1, and Bdnf. Furthermore, GH treatment increased both the nuclear content of KLF13 and Klf13 mRNA levels, suggesting that KLF13 could be part of the mechanisms that maintain the homeostatic state of this pathway. These findings support the notion that KLF13 is a regulator of JAK/STAT activity.
Subject(s)
Janus Kinases , Signal Transduction , Janus Kinases/genetics , Janus Kinases/metabolism , STAT Transcription Factors/genetics , STAT Transcription Factors/metabolism , Suppressor of Cytokine Signaling Proteins/metabolism , STAT3 Transcription Factor/genetics , STAT3 Transcription Factor/metabolism , RNA, Messenger/metabolismABSTRACT
Several cytokines with major biological functions in inflammatory diseases exert their functions through the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signal transduction pathway. JAKs phosphorylate the cytoplasmic domain of the receptor, inducing the activation of its substrates, mainly the proteins known as STATs. STATs bind to these phosphorylated tyrosine residues and translocate from the cytoplasm to the nucleus, further regulating the transcription of several genes that regulate the inflammatory response. The JAK/STAT signaling pathway plays a critical role in the pathogenesis of inflammatory diseases. There is also increasing evidence indicating that the persistent activation of the JAK/STAT signaling pathway is related to several inflammatory bone (osteolytic) diseases. However, the specific mechanism remains to be clarified. JAK/STAT signaling pathway inhibitors have gained major scientific interest to explore their potential in the prevention of the destruction of mineralized tissues in osteolytic diseases. Here, our review highlights the importance of the JAK/STAT signaling pathway in inflammation-induced bone resorption and presents the results of clinical studies and experimental models of JAK inhibitors in osteolytic diseases.
Subject(s)
Janus Kinases , STAT Transcription Factors , Humans , Janus Kinases/metabolism , STAT Transcription Factors/metabolism , Signal Transduction/physiology , Cytokines/metabolism , Inflammation/drug therapyABSTRACT
The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathway constitutes a rapid signaling module from the cell surface to the nucleus, and activates different cellular responses, such as proliferation, survival, migration, invasion, and inflammation. When the JAK/STAT pathway is altered, it contributes to cancer progression and metastasis. STAT proteins play a central role in developing cervical cancer, and inhibiting the JAK/STAT signaling may be necessary to induce tumor cell death. Several cancers show continuous activation of different STATs, including cervical cancer. The constitutive activation of STAT proteins is associated with a poor prognosis and overall survival. The human papillomavirus (HPV) oncoproteins E6 and E7 play an essential role in cervical cancer progression, and they activate the JAK/STAT pathway and other signals that induce proliferation, survival, and migration of cancer cells. Moreover, there is a crosstalk between the JAK/STAT signaling cascade with other signaling pathways, where a plethora of different proteins activate to induce gene transcription and cell responses that contribute to tumor growth. Therefore, inhibition of the JAK/STAT pathway shows promise as a new target in cancer treatment. In this review, we discuss the role of the JAK/STAT pathway components and the role of the HPV oncoproteins associated with cellular malignancy through the JAK/STAT proteins and other signaling pathways to induce tumor growth.
Subject(s)
Papillomavirus Infections , Uterine Cervical Neoplasms , Female , Humans , Janus Kinases/genetics , Janus Kinases/metabolism , Signal Transduction/physiology , Uterine Cervical Neoplasms/genetics , Papillomavirus Infections/genetics , STAT Transcription Factors/genetics , STAT Transcription Factors/metabolismABSTRACT
The JAK-STAT signaling pathway mediates important cellular processes such as immune response, carcinogenesis, cell differentiation, division and death. Therefore, drugs that interfere with different JAK-STAT signaling patterns have potential indications for various medical conditions. The main dermatological targets of JAK-STAT pathway inhibitors are inflammatory or autoimmune diseases such as psoriasis, vitiligo, atopic dermatitis and alopecia areata; however, several dermatoses are under investigation to expand this list of indications. As JAK-STAT pathway inhibitors should gradually occupy a relevant space in dermatological prescriptions, this review presents the main available drugs, their immunological effects, and their pharmacological characteristics, related to clinical efficacy and safety, aiming to validate the best dermatological practice.
Subject(s)
Dermatology , Janus Kinase Inhibitors , Vitiligo , Humans , Janus Kinase Inhibitors/pharmacology , Janus Kinase Inhibitors/therapeutic use , Janus Kinases/metabolism , Janus Kinases/pharmacology , Signal Transduction , STAT Transcription Factors/metabolism , STAT Transcription Factors/pharmacology , Vitiligo/drug therapyABSTRACT
PURPOSE: To investigate the role of cyanidin-3-O-glucoside (C3G) in renal ischemia/reperfusion (I/R) injury and the potential mechanisms. METHODS: Mouse models were established by clamping the left renal vessels, and in vitro cellular models were established by hypoxic reoxygenation. RESULTS: Renal dysfunction and tissue structural damage were significantly higher in the I/R group. After treatment with different concentrations of C3G, the levels of renal dysfunction and tissue structural damage decreased at different levels. And its protective effect was most pronounced at 200 mg/kg. The use of C3G reduced apoptosis as well as the expression of endoplasmic reticulum stress (ERS)-related proteins. Hypoxia/reoxygenation (H/R)-induced apoptosis and ERS are dependent on oxidative stress in vitro. In addition, both AG490 and C3G inhibited the activation of JAK/STAT pathway and attenuated oxidative stress, ischemia-induced apoptosis and ERS. CONCLUSIONS: The results demonstrated that C3G blocked renal apoptosis and ERS protein expression by preventing reactive oxygen species (ROS) production after I/R via the JAK/STAT pathway, suggesting that C3G may be a potential therapeutic agent for renal I/R injury.
Subject(s)
Kidney Diseases , Reperfusion Injury , Mice , Animals , Janus Kinases/metabolism , Janus Kinases/pharmacology , Janus Kinases/therapeutic use , Signal Transduction , STAT Transcription Factors/metabolism , STAT Transcription Factors/pharmacology , STAT Transcription Factors/therapeutic use , Reperfusion Injury/metabolism , Apoptosis , Ischemia , Glucosides/pharmacologyABSTRACT
Multiple sclerosis (MS) is a chronic demyelinating autoimmune disease that affects the central nervous system (CNS), varying from relatively benign to severely disabling. Although the roles of several cytokines and chemokines in MS are well established, their roles in MS lesions and evolution remain a matter of debate. Soluble CD40L (sCD40L) is a ligand that induces lymphocyte proinflammatory activity by stimulating the activation and maturation of B cells, promoting isotype switching and affinity hypermutation. Circulating sCD40L levels reflect activation of the CD40-CD40L complex. The interaction between CD40 and CD40L is of fundamental importance, suggesting their role in MS pathogenesis. Interleukin-31 (IL-31) is a proinflammatory cytokine that plays a role in allergies, autoimmune diseases, and is a major factor in several chronic inflammatory diseases. IL-31 triggers the JAK-STAT pathway in several different cell types, to induce proliferation and tissue remodeling in fibroblasts, epithelial cells, and endothelial cells. Some studies have described a correlation between these two cytokines and decreased serum levels of sCD40L and IL-31 after MS treatment, accompanied by a lower inflammatory response. In this review, we emphasize the possible correlation and positive feedback between IL31 and sCD40L in the MS proinflammatory response. We also describe the justification for this hypothesis and whether it is possible to investigate these cytokines as biomarkers of MS.
Subject(s)
CD40 Ligand , Multiple Sclerosis , Humans , CD40 Ligand/metabolism , Endothelial Cells/metabolism , Janus Kinases/metabolism , STAT Transcription Factors/metabolism , Signal Transduction , Biomarkers , Interleukins , CytokinesABSTRACT
OBJECTIVES: TTP488, an antagonist of the receptor for advanced glycation end-products, was evaluated as a potential treatment for patients with mild-to-moderate Alzheimer's disease (AD). However, the mechanism underlying the protective action of TTP488 against AD has not yet been fully explored. METHODS: Healthy male rats were exposed to aberrant amyloid ß (Aß) 1-42. Lipopolysaccharide (LPS) and the NOD-like receptor family pyrin domain containing 1 (NLRP1) overexpression lentivirus were injected to activate the NLRP1 inflammasome and exacerbate AD. TTP488 was administered to reverse AD injury. Finally, tofacitinib and fludarabine were used to inhibit the activity of Janus tyrosine kinase (JAK) and signal transducer and activator of transcription (STAT) to prove the relationship between the JAK/STAT signaling pathway and TTP488. RESULTS: LPS and NLRP1 overexpression significantly increased the NLRP1 levels, reduced neurological function, and aggravated neuronal damage, as demonstrated by the impact latency time of, time spent by, and length of the platform covered by, the mice in the Morris water maze assay, Nissl staining, and immunofluorescence staining in rats with AD. CONCLUSIONS: TTP488 administration successfully reduced AD injury and reversed the aforementioned processes. Additionally, tofacitinib and fludarabine administration could further reverse AD injury after the TTP488 intervention. These results suggest a new potential mechanism underlying the TTP488-mediated alleviation of AD injury.
Subject(s)
Alzheimer Disease , Imidazoles , Janus Kinases , STAT Transcription Factors , Signal Transduction , Alzheimer Disease/drug therapy , Amyloid beta-Peptides , Animals , Imidazoles/pharmacology , Janus Kinase 2 , Janus Kinases/metabolism , Male , Mice , Rats , Receptor for Advanced Glycation End Products , STAT Transcription Factors/metabolism , TyrosineABSTRACT
OBJECTIVE: Altered homeostasis of salivary gland (SG) epithelial cells in Sjögren's syndrome (SS) could be the initiating factor that leads to inflammation, secretory dysfunction and autoimmunity. Autophagy is an important homeostatic mechanism, whose deficiency is associated with inflammation and accumulation of Janus kinase (JAK)-signal transducer and activator of transcription (STAT) components. We aimed to evaluate whether autophagy is altered in labial SG (LSG) epithelial cells from primary SS (pSS) patients and whether this contributes to inflammation through the JAK-STAT pathway. Furthermore, we investigated the anti-inflammatory effect of the JAK inhibitor tofacitinib in autophagy-deficient (ATG5 knockdown) three-dimensional (3D)-acini. METHODS: We analysed LSG biopsies from 12 pSS patients with low focus score and 10 controls. ATG5-deficient 3D-acini were generated and incubated with IL-6 in the presence or absence of tofacitinib. Autophagy markers, pro-inflammatory cytokine expression, and JAK-STAT pathway activation were evaluated by PCR or western blot, along with correlation analyses between the evaluated markers and clinical parameters. RESULTS: LSG from pSS patients showed increased p62 and decreased ATG5 expression, correlating negatively with increased activation of JAK-STAT pathway components (pSTAT1 and pSTAT3). Increased expression of STAT1 and IL-6 correlated with EULAR Sjögren's syndrome disease activity index and the presence of anti-Ro antibodies. ATG5-deficient 3D-acini reproduced the findings observed in LSG from pSS patients, showing increased expression of pro-inflammatory markers such as IL-6, which was reversed by tofacitinib. CONCLUSION: Decreased expression of ATG5 in LSG epithelial cells from pSS patients possibly contributes to increased inflammation associated with JAK-STAT pathway activation, as evidenced in ATG5-deficient 3D-acini. Interestingly, these results suggest that tofacitinib could be used as an anti-inflammatory agent in pSS patients.
Subject(s)
Autophagy/drug effects , Interleukin-6/metabolism , Piperidines/pharmacology , Pyrimidines/pharmacology , Adolescent , Adult , Aged , Blotting, Western , Case-Control Studies , Female , Fluorescent Antibody Technique , Humans , Interleukin-6/antagonists & inhibitors , Janus Kinases/metabolism , Male , Middle Aged , Piperidines/therapeutic use , Pyrimidines/therapeutic use , Real-Time Polymerase Chain Reaction , STAT Transcription Factors/metabolism , Salivary Glands/drug effects , Salivary Glands/metabolism , Signal Transduction/drug effects , Sjogren's Syndrome , Young AdultABSTRACT
ANKHD1 (ankyrin repeat and KH domain containing 1) is a large protein characterized by the presence of multiple ankyrin repeats and a K-homology domain. Ankyrin repeat domains consist of widely existing protein motifs in nature, they mediate protein-protein interactions and regulate fundamental biological processes, while the KH domain binds to RNA or ssDNA and is associated with transcriptional and translational regulation. In recent years, studies containing relevant information on ANKHD1 in cancer biology and its clinical relevance, as well as the increasing complexity of signaling networks in which this protein acts, have been reported. Among the signaling pathways of interest in oncology regulated by ANKHD1 are Hippo signaling, JAK/STAT, and STMN1. The scope of the present review is to survey the current knowledge and highlight future perspectives for ANKHD1 in the malignant phenotype of cancer cells, exploring biological, functional, and clinical reports of this protein in cancer. [BMB Reports 2020; 53(8): 413-418].
Subject(s)
Neoplasms/genetics , Neoplasms/metabolism , RNA-Binding Proteins/metabolism , Adaptor Proteins, Signal Transducing/metabolism , Amino Acid Motifs , Binding Sites/genetics , Biological Phenomena , Cell Line, Tumor , Cell Proliferation/genetics , Gene Expression Regulation, Neoplastic/genetics , Humans , Janus Kinase 1/metabolism , Protein Domains/physiology , RNA/metabolism , RNA-Binding Proteins/genetics , RNA-Binding Proteins/physiology , STAT Transcription Factors/metabolism , Signal Transduction/genetics , Signal Transduction/physiology , Stathmin/metabolism , Transcription Factors/metabolism , YAP-Signaling ProteinsABSTRACT
Membrane expression of fractalkine (CX3CL1)-receptor (CX3CR1) is relevant in monocytes (Mo) because CX3CR1-CX3CL1 interactions might participate on both, homeostatic and pathologic conditions. We have previously demonstrated that CX3CR1 levels are decreased during culture and when Mo are differentiated into dendritic cells, but enhanced when differentiated into macrophages. Regarding soluble factors, lipopolysaccharide (LPS) accelerated the loss of CX3CR1, while interleukin (IL)-10 and Interferon-gamma (IFN-γ) prevented it. However, the comprehensive knowledge about the intracellular pathways that underlay the level of CX3CR1 expression in Mo is still incomplete. In the current work, we studied the effect of anti-inflammatory cytokines (IL-4, IL-13, IL-10), alone or together with IFN- γ on CX3CR1 expression. We found that only IL-10 and IFN-γ separately were able to prevent CX3CR1 down-modulation during culture of human Mo. Besides, Mo incubated with IL-10 plus IFN-γ showed the highest CX3CR1 expression by cell, suggesting cooperation between two different mechanism used by both cytokines. By studying intracellular mechanisms triggered by IL-10 and IFN-γ, we demonstrated that they specifically induced PI3K-dependent serine-phosphorylation of signal transducer and activator of transcription (STAT)3 or STAT1, respectively. Moreover, chemical inhibitors of STAT1 or STAT3 abrogated IFN-γ or IL-10 effects on CX3CR1 expression. Strikingly, only IL-10 increased CX3CR1 mRNA level, as consequence of augmenting mRNA stability. CX3CR1 mRNA increase was PI3K-dependent, supporting the causal link between the action of IL-10 at the CX3CR1 transcript and CX3CR1 protein level on Mo. Thus, both cytokines up-regulate CX3CR1 expression on human Mo by different intracellular mechanisms.
Subject(s)
CX3C Chemokine Receptor 1/metabolism , Interferon-gamma/metabolism , Interleukin-10/metabolism , Monocytes/metabolism , Up-Regulation , CX3C Chemokine Receptor 1/genetics , Humans , Phosphatidylinositol 3-Kinases/metabolism , Phosphorylation , RNA, Messenger/genetics , RNA, Messenger/metabolism , STAT Transcription Factors/metabolism , Serine/metabolismABSTRACT
JAK proteins have been linked with survival and proliferation of multiple myeloma (MM) cells; therefore, JAK inhibition could be a therapeutic strategy for MM. We evaluated JAK1 and JAK2 expression in MM patients and the effects of JAK/STAT pathway inhibition on apoptosis, cell cycle, gene and protein expression in RPMI-8226 and U266 MM cell lines. 57% of patients presented overexpression of JAK2 and 27%, of JAK1. After treatment with ruxolitinib and bortezomib, RPMI-8226 and U266 presented 50% of cells in late apoptosis, reduction of anti-apoptotic genes expression and higher number of cells in SubG0 phase. Co-culture with stromal cells protected RPMI-8226 cells from apoptosis, which was reversed by lenalidomide addition. Combination of ruxolitinib, bortezomib and lenalidomide induced 72% of cell death, equivalent to bortezomib, lenalidomide and dexamethasone, combination used in clinical practice. Many JAK/STAT pathway genes, after treatment, had their expression reduced, mainly in RPMI-8226, with insignificant changes in U266. In this scenario, JAK/STAT pathway could pose as a new therapeutic target to be exploited, since it is constitutively active and contributes to survival of MM tumor cells.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/pharmacology , Bortezomib/pharmacology , Janus Kinase 1/antagonists & inhibitors , Janus Kinase 2/antagonists & inhibitors , Multiple Myeloma/drug therapy , Pyrazoles/pharmacology , STAT Transcription Factors/metabolism , Signal Transduction/drug effects , Thalidomide/analogs & derivatives , Adult , Aged , Aged, 80 and over , Apoptosis/drug effects , Apoptosis Regulatory Proteins/genetics , Apoptosis Regulatory Proteins/metabolism , Cell Cycle/drug effects , Cell Cycle Proteins/genetics , Cell Cycle Proteins/metabolism , Cell Line, Tumor , Coculture Techniques , Dose-Response Relationship, Drug , Female , Gene Expression Regulation, Neoplastic , Humans , Janus Kinase 1/genetics , Janus Kinase 1/metabolism , Janus Kinase 2/genetics , Janus Kinase 2/metabolism , Lenalidomide , Male , Middle Aged , Multiple Myeloma/enzymology , Multiple Myeloma/genetics , Multiple Myeloma/pathology , Nitriles , Pyrimidines , Stromal Cells/drug effects , Stromal Cells/metabolism , Stromal Cells/pathology , Thalidomide/pharmacology , Time FactorsABSTRACT
IL-6 is a pleiotropic cytokine with multiple pathophysiological functions. As a key factor of the senescence secretome, it can not only promote tumorigenesis and cell proliferation but also exert tumor suppressive functions, depending on the cellular context. IL-6, as do other cytokines, plays important roles in the function, growth and neuroendocrine responses of the anterior pituitary gland. The multiple actions of IL-6 on normal and adenomatous pituitary function, cell proliferation, angiogenesis and extracellular matrix remodeling indicate its importance in the regulation of the anterior pituitary. Pituitary tumors are mostly benign adenomas with low mitotic index and rarely became malignant. Premature senescence occurs in slow-growing benign tumors, like pituitary adenomas. The dual role of IL-6 in senescence and tumorigenesis is well represented in pituitary tumor development, as it has been demonstrated that effects of paracrine IL-6 may allow initial pituitary cell growth, whereas autocrine IL-6 in the same tumor triggers senescence and restrains aggressive growth and malignant transformation. IL-6 is instrumental in promotion and maintenance of the senescence program in pituitary adenomas.
Subject(s)
Adenoma/genetics , Cellular Senescence/genetics , Interleukin-6/genetics , Neovascularization, Pathologic/genetics , Pituitary Gland, Anterior/metabolism , Pituitary Neoplasms/genetics , Adenoma/metabolism , Adenoma/pathology , Animals , Autocrine Communication/genetics , Cell Cycle/genetics , Cell Proliferation , Extracellular Matrix/metabolism , Extracellular Matrix/pathology , Gene Expression Regulation , Humans , Interleukin-6/metabolism , Mitogen-Activated Protein Kinase Kinases/genetics , Mitogen-Activated Protein Kinase Kinases/metabolism , Neovascularization, Pathologic/metabolism , Neovascularization, Pathologic/pathology , Paracrine Communication/genetics , Phosphatidylinositol 3-Kinases/genetics , Phosphatidylinositol 3-Kinases/metabolism , Pituitary Gland, Anterior/pathology , Pituitary Neoplasms/metabolism , Pituitary Neoplasms/pathology , STAT Transcription Factors/genetics , STAT Transcription Factors/metabolismABSTRACT
Mosquito-transmitted flavivirus Rocio (ROCV) was responsible for an outbreak of encephalitis in the Ribeira Valley, located in the south coast of Sao Paulo State, Brazil, in 1975-1976. ROCV also causes fatal encephalitis in adult mice. Seroprevalence studies in humans, horses and water buffaloes in different regions of Brazil have suggested that ROCV is still circulating in the country, indicating the risk of re-emergence of this virus. West Nile virus (WNV) is also a mosquito-transmitted encephalitic flavivirus, however, WNV strains circulating in Australia have not been associated with outbreaks of disease in humans and exhibit low virulence in adult mice. To identify viral determinants of ROCV virulence, we have generated reciprocal chimeric viruses between ROCV and the Australian strain of WNV by swapping structural prM and E genes. Chimeric WNV containing ROCV prM-E genes replicated more efficiently than WNV or chimeric ROCV containing WNV prM-E genes in mammalian cells, was as virulent as ROCV in adult mice, and inhibited type I IFN signaling as efficiently as ROCV. The results show that ROCV prM and E proteins are major virulence determinants and identify unexpected function of these proteins in inhibition of type I interferon response.
Subject(s)
Flaviviridae/pathogenicity , Interferon-alpha/metabolism , Interferon-beta/metabolism , Signal Transduction , Viral Proteins/metabolism , West Nile virus/pathogenicity , Animals , Cloning, Molecular , DNA, Complementary/genetics , Female , HEK293 Cells , Humans , Janus Kinases/metabolism , Mice, Inbred C57BL , Phosphorylation , STAT Transcription Factors/metabolism , Virulence , Virus ReplicationABSTRACT
INTRODUCTION: Current available treatments for inflammatory bowel disease (IBD) have some limitations and new options are needed. Several new molecules are being tested for the treatment of IBD and other immune-mediated inflammatory diseases. Among them, Janus kinase (JAK) inhibitors seem to have the lead, since tofacitinib has received regulatory approval in 2012 for the treatment of rheumatoid arthritis, and also it has shown a favorable risk-benefit ratio in phase 3 studies for ulcerative colitis, both in anti-TNF naïve and anti-TNF experienced patients. Other compounds with JAK inhibitory activity are also being tested with promising results. Areas covered: This review discusses the molecular aspects of the JAK-STAT pathway, which gives rationale for the use of JAK inhibitors in immune-mediated inflammatory diseases, especially in IBD. Different compounds with JAK inhibitory activity are presented, and relevant efficacy and safety data in IBD and other conditions are discussed. Expert commentary: It would not be surprising that in a foreseeable future many new orally administrated drugs will be available. This enhanced armamentarium will probably pose new dilemmas, in terms of drug positioning, escalation and de-escalation strategies, and combination therapy.
Subject(s)
Arthritis, Rheumatoid/drug therapy , Inflammatory Bowel Diseases/drug therapy , Janus Kinases/antagonists & inhibitors , Piperidines/therapeutic use , Protein Kinase Inhibitors/therapeutic use , Pyrimidines/therapeutic use , Pyrroles/therapeutic use , Animals , Clinical Trials as Topic , Humans , Molecular Targeted Therapy , Risk Assessment , STAT Transcription Factors/metabolism , Signal TransductionABSTRACT
Transgenic mice overexpressing growth hormone (GH) show increased hepatic protein content of the epidermal growth factor receptor (EGFR), which is broadly associated with cell proliferation and oncogenesis. However, chronically elevated levels of GH result in desensitization of STAT-mediated EGF signal and similar response of ERK1/2 and AKT signaling to EGF compared to normal mice. To ascertain the mechanisms involved in GH attenuation of EGF signaling and the consequences on cell cycle promotion, phosphorylation of signaling mediators was studied at different time points after EGF stimulation, and induction of proteins involved in cell cycle progression was assessed in normal and GH-overexpressing transgenic mice. Results from kinetic studies confirmed the absence of STAT3 and 5 activation and comparable levels of ERK1/2 phosphorylation upon EGF stimulation, which was associated with diminished or similar induction of c-MYC, c-FOS, c-JUN, CYCLIN D1 and CYCLIN E in transgenic compared to normal mice. Accordingly, kinetics of EGF-induced c-SRC and EGFR phosphorylation at activating residues demonstrated that activation of these proteins was lower in the transgenic mice with respect to normal animals. In turn, EGFR phosphorylation at serine 1046/1047, which is implicated in the negative regulation of the receptor, was increased in the liver of GH-overexpressing transgenic mice both in basal conditions and upon EGF stimulus. Increased basal phosphorylation and activation of the p38-mitogen-activated protein kinase might account for increased Ser 1046/1047 EGFR. Hyperphosphorylation of EGFR at serine residues would represent a compensatory mechanism triggered by chronically elevated levels of GH to mitigate the proliferative response induced by EGF.
Subject(s)
Epidermal Growth Factor/pharmacology , Gene Expression Regulation/physiology , Growth Hormone/metabolism , Signal Transduction/physiology , Animals , ErbB Receptors/genetics , ErbB Receptors/metabolism , Extracellular Signal-Regulated MAP Kinases/genetics , Extracellular Signal-Regulated MAP Kinases/metabolism , Genes, src/genetics , Genes, src/physiology , Growth Hormone/genetics , Humans , Liver/metabolism , Mice , Mice, Transgenic , STAT Transcription Factors/genetics , STAT Transcription Factors/metabolism , p38 Mitogen-Activated Protein Kinases/genetics , p38 Mitogen-Activated Protein Kinases/metabolismABSTRACT
The effective defense against parasite infections requires the ability to mount an appropriate and controlled specific immune response able to eradicate the invading pathogen while limiting the collateral damage to self-tissues. Dendritic cells are key elements for the development of immunity against parasites; they control the responses required to eliminate these pathogens while maintaining host homeostasis. Ligation of dendritic cell pattern recognition receptors by pathogen-associated molecular pattern present in the parasites initiates signaling pathways that lead to the production of surface and secreted proteins that are required, together with the antigen, to induce an appropriate and timely regulated immune response. There is evidence showing that parasites can influence and regulate dendritic cell functions in order to promote a more permissive environment for their survival. In this review, we will focus on new insights about the ability of protozoan and helminth parasites or their products to modify dendritic cell function and discuss how this interaction is crucial in shaping the host response.
Subject(s)
Dendritic Cells/immunology , Dendritic Cells/metabolism , Host-Parasite Interactions/immunology , Parasites/immunology , Parasitic Diseases/immunology , Parasitic Diseases/metabolism , Animals , Humans , Immune System/cytology , Immune System/immunology , Immune System/metabolism , Immune Tolerance , Janus Kinases/metabolism , Parasitic Diseases/parasitology , STAT Transcription Factors/metabolism , Signal Transduction , T-Lymphocyte Subsets/immunology , T-Lymphocyte Subsets/metabolism , Toll-Like Receptors/metabolismABSTRACT
Atopic dermatitis (AD) is a chronic inflammatory skin disease that affects up to 25% of children and 10% of adults. The skin of patients with moderate to severe AD is characterized by significant barrier disruption and T helper 2 (Th2)-driven inflammation, which are thought to play a significant role in the pathogenesis of AD. Current management of AD is aimed at suppressing the inflammatory response and restoring the barrier function of the skin, reducing exacerbations, and preventing secondary skin infections. Combinations of treatment strategies are used to alleviate the symptoms of the disease; however, resolution is often temporary, and long-term usage of some of the medications for AD can be associated with significant side effects. Antibody therapies previously approved for other inflammatory diseases have been evaluated in patients with AD. Unfortunately, they have often failed to result in significant clinical improvement. Monoclonal antibodies and novel small molecules currently in development may provide more consistent benefit to patients with AD by specifically targeting the immune and molecular pathways important for the pathogenesis of AD. Here we review the state-of-the-art therapeutics targeting the Th2 axis in AD.