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Canine gastrointestinal lymphoma is known to be of T-cell origin in most cases, but the molecular biological aberrations have not been clarified. In human intestinal T-cell lymphoma, the mutations in the genes associated with Janus kinase/signal transducer and activator of transcription (JAK-STAT) pathway have been frequently observed. In this study, the gene mutations were investigated in 31 dogs with large cell gastrointestinal lymphoma (LCGIL) by focusing on the genes involved in JAK-STAT pathway. Next-generation sequencing analysis to examine the mutations in STAT3, STAT5B, and JAK1 genes throughout the exon regions revealed the mutations in STAT3 gene in two dogs and JAK1 gene in one dog. In conclusion, this study could not indicate the associations of gene mutations in JAK-STAT pathway with LCGIL in most canine cases. [ABSTRACT FROM AUTHOR]

Atopic dermatitis is a chronic inflammatory dermatosis characterized by pruritic, scaly, erythematous lesions. Its incidence varies but is estimated to be approximately 20% in children and between 7 and 14% in adults, with variation amongst countries. It is a multifactorial condition, with a complex interplay between genetic, immunological, and environmental factors. Research into the inflammatory response has identified new therapeutic targets that work to reduce inflammation and subsequently reduce flares. This study explores existing therapeutic agents for atopic dermatitis as well as newer therapies such as biologics and small molecules, drawing upon each agent's mechanism of action, relevant landmark clinical trials, efficacy, and safety profile. Current therapies include emollients, corticosteroids, cyclosporine A, calcineurin inhibitors, phototherapy, and methotrexate. Biologics described include dupilumab, tralokinumab, lebrikizumab, nemolizumab, and rocatinlimab. Small molecules inhibitors include Janus kinase inhibitors, phosphodiesterase 4 inhibitors, transient receptor potential vanilloid subfamily V member 1 antagonist, and aryl hydrocarbon receptor antagonist. [ABSTRACT FROM AUTHOR]

The JAK/STAT signaling pathway plays a key role in cytokine signaling and is involved in development, immunity, and tumorigenesis for nearly any cell. At first glance, the JAK/STAT signaling pathway appears to be straightforward. However, on closer examination, the factors influencing the JAK/STAT signaling activity, such as cytokine diversity, receptor profile, overlapping JAK and STAT specificity among non-redundant functions of the JAK/STAT complexes, positive regulators (e.g., cooperating transcription factors), and negative regulators (e.g., SOCS, PIAS, PTP), demonstrate the complexity of the pathways architecture, which can be quickly disturbed by mutations. The JAK/STAT signaling pathway has been, and still is, subject of basic research and offers an enormous potential for the development of new methods of personalized medicine and thus the translation of basic molecular research into clinical practice beyond the use of JAK inhibitors. Gain-of-function and loss-of-function mutations in the three immunologically particularly relevant signal transducers STAT1, STAT3, and STAT6 as well as JAK1 and JAK3 present themselves through individual phenotypic clinical pictures. The established, traditional paradigm of loss-of-function mutations leading to immunodeficiency and gain-of-function mutation leading to autoimmunity breaks down and a more differentiated picture of disease patterns evolve. This review is intended to provide an overview of these specific syndromes from a clinical perspective and to summarize current findings on pathomechanism, symptoms, immunological features, and therapeutic options of STAT1, STAT3, STAT6, JAK1, and JAK3 loss-of-function and gain-of-function diseases.

Severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) induced cytokine storm is the major cause of COVID-19 related deaths. Patients have been treated with drugs that work by inhibiting a specific protein partly responsible for the cytokines production. This approach provided very limited success, since there are multiple proteins involved in the complex cell signaling disease mechanisms. We targeted five proteins: Angiotensin II receptor type 1 (AT1R), A disintegrin and metalloprotease 17 (ADAM17), Nuclear Factor‑Kappa B (NF‑κB), Janus kinase 1 (JAK1) and Signal Transducer and Activator of Transcription 3 (STAT3), which are involved in the SARS‑CoV‑2 induced cytokine storm pathway. We developed machine-learning (ML) models for these five proteins, using known active inhibitors. After developing the model for each of these proteins, FDA-approved drugs were screened to find novel therapeutics for COVID‑19. We identified twenty drugs that are active for four proteins with predicted scores greater than 0.8 and eight drugs active for all five proteins with predicted scores over 0.85. Mitomycin C is the most active drug across all five proteins with an average prediction score of 0.886. For further validation of these results, we used the PyRx software to conduct protein-ligand docking experiments and calculated the binding affinity. The docking results support findings by the ML model. This research study predicted that several drugs can target multiple proteins simultaneously in cytokine storm-related pathway. These may be useful drugs to treat patients because these therapies can fight cytokine storm caused by the virus at multiple points of inhibition, leading to synergistically effective treatments.

The family of Janus Kinases (JAKs) associated with the JAK–signal transducers and activators of transcription signaling pathway plays a vital role in the regulation of various cellular processes. The conformational change of JAKs is the fundamental steps for activation, affecting multiple intracellular signaling pathways. However, the transitional process from inactive to active kinase is still a mystery. This study is aimed at investigating the electrostatic properties and transitional states of JAK1 to a fully activation to a catalytically active enzyme. To achieve this goal, structures of the inhibited/activated full-length JAK1 were modelled and the energies of JAK1 with Tyrosine Kinase (TK) domain at different positions were calculated, and Dijkstra's method was applied to find the energetically smoothest path. Through a comparison of the energetically smoothest paths of kinase inactivating P733L and S703I mutations, an evaluation of the reasons why these mutations lead to negative or positive regulation of JAK1 are provided. Our energy analysis suggests that activation of JAK1 is thermodynamically spontaneous, with the inhibition resulting from an energy barrier at the initial steps of activation, specifically the release of the TK domain from the inhibited Four-point-one, Ezrin, Radixin, Moesin-PK cavity. Overall, this work provides insights into the potential pathway for TK translocation and the activation mechanism of JAK1. [ABSTRACT FROM AUTHOR]

Abstract Acute myeloid leukemia (AML), characterized by the abnormal accumulation of immature marrow cells in the bone marrow, is a malignant tumor of the blood system. Currently, the pathogenesis of AML is not yet clear. Therefore, this study aims to explore the mechanisms underlying the development of AML. Firstly, we identified a competing endogenous RNA (ceRNA) SUCLG2-AS1-miR-17-5p-JAK1 axis through bioinformatics analysis. Overexpression of SUCLG2-AS1 inhibits proliferation, migration and invasion and promotes apoptosis of AML cells. Secondly, luciferase reporter assay and RIP assay validated that SUCLG2-AS1 functioned as ceRNA for sponging miR-17-5p, further leading to JAK1 underexpression. Additionally, the results of MeRIP-qPCR and m6A RNA methylation quantification indicted that SUCLG2-AS1(lncRNA) had higher levels of m6A RNA methylation compared with controls, and SUCLG2-AS1 is regulated by m6A modification of WTAP in AML cells. WTAP, one of the main regulatory components of m6A methyltransferase complexes, proved to be highly expressed in AML and elevated WTAP is associated with poor prognosis of AML patients. Taken together, the WTAP-SUCLG2-AS1-miR-17-5p-JAK1 axis played essential roles in the process of AML development, which provided a novel therapeutic target for AML.

Acute myeloid leukemia (AML), characterized by the abnormal accumulation of immature marrow cells in the bone marrow, is a malignant tumor of the blood system. Currently, the pathogenesis of AML is not yet clear. Therefore, this study aims to explore the mechanisms underlying the development of AML. Firstly, we identified a competing endogenous RNA (ceRNA) SUCLG2-AS1-miR-17-5p-JAK1 axis through bioinformatics analysis. Overexpression of SUCLG2-AS1 inhibits proliferation, migration and invasion and promotes apoptosis of AML cells. Secondly, luciferase reporter assay and RIP assay validated that SUCLG2-AS1 functioned as ceRNA for sponging miR-17-5p, further leading to JAK1 underexpression. Additionally, the results of MeRIP-qPCR and m6A RNA methylation quantification indicted that SUCLG2-AS1(lncRNA) had higher levels of m6A RNA methylation compared with controls, and SUCLG2-AS1 is regulated by m6A modification of WTAP in AML cells. WTAP, one of the main regulatory components of m6A methyltransferase complexes, proved to be highly expressed in AML and elevated WTAP is associated with poor prognosis of AML patients. Taken together, the WTAP-SUCLG2-AS1-miR-17-5p-JAK1 axis played essential roles in the process of AML development, which provided a novel therapeutic target for AML. [ABSTRACT FROM AUTHOR]

Simple Summary: MicroRNA (miR) 494-5p has been associated with cancer progression, but molecules mediating this are not well understood. Here, we show that the 3'UTR of JAK1 is physically targeted, and JAK1 is downregulated in expression by miR-494-5p in colorectal cancer (CRC). Additionally, CRC cell proliferation, spontaneous and IL-4-induced invasion, and migration were significantly reduced by this miR, as well as IL-4-induced phosphorylation of JAK1, STAT6, and AKT. High JAK1 expression significantly correlated with reduced patient survival. Together, our findings suggest JAK1 as a novel target of miR-494-5p, with its translational repression contributing to CRC progression and the initial steps of metastasis. MiR-494-5p expression has been suggested to be associated with colorectal cancer (CRC) and its metastases in our previous studies. However, functional investigations on the molecule-mediating actions of this miR in CRC are lacking. In silico analysis in the present study revealed a putative binding sequence within the 3′UTR of JAK1. Overexpression of miR-494-5p in cultured CRC significantly reduced the luciferase activity of a reporter plasmid containing the wild-type JAK1-3′UTR, which was abolished by seed sequence mutation. Furthermore, the overexpression of miR-494-5p in CRC cell lines led to a significant reduction in JAK1 expression, proliferation, in vitro migration, and invasion. These effects were abolished by co-transfection with a specific double-stranded RNA that inhibits endogenous miR-494-5p. Moreover, IL-4-induced migration, invasion, and phosphorylation of JAK1, STAT6, and AKT proteins were reduced after an overexpression of this miR, suggesting that this miR affects one of the most essential pathways in CRC. A Kaplan–Meier plotter analysis revealed that patients with high JAK1 expression show reduced survival. Together, these data suggest that miR-494-5p physically inhibits the expression of JAK1 at the translational level as well as in migration and invasion, supporting the hypothesis of miR-494-5p as an early tumor suppressor and inhibitor of early steps of metastasis in CRC. [ABSTRACT FROM AUTHOR]

This hypothesis-generating study characterized the mRNA expression profiles and prognostic impacts of antigen-presenting cell (APC) markers (CD14, CD163, CD86, and ITGAX/CD11c) in pediatric brainstem diffuse midline glioma (pbDMG) tumors. We also assessed the mRNA levels of two therapeutic targets, transforming growth factor beta 2 (TGFB2) and interferon gamma receptor 2 (IFNGR2), for their biomarker potentials in these highly aggressive pbDMG tumors. The expressions of CD14, CD163, and ITGAX/CD11c mRNAs exhibited significant decreases of 1.64-fold (p = 0.037), 1.75-fold (p = 0.019), and 3.33-fold (p < 0.0001), respectively, in pbDMG tumors relative to those in normal brainstem/pons samples. The pbDMG samples with high levels of TGFB2 in combination with low levels of APC markers, reflecting the cold immune state of pbDMG tumors, exhibited significantly worse overall survival outcomes at low expression levels of CD14, CD163, and CD86. The expression levels of IFNGR2 and TGFB2 (1.51-fold increase (p = 0.002) and 1.58-fold increase (p = 5.5 × 10−4), respectively) were significantly upregulated in pbDMG tumors compared with normal brainstem/pons samples. We performed multivariate Cox proportional hazards modelling that showed TGFB2 was a prognostic indicator (HR for patients in the TGFB2high group of pbDMG patients = 2.88 (1.12–7.39); p = 0.028) for poor overall survival (OS) and was independent of IFNGR2 levels, the age of the patient, and the significant interaction effect observed between IFNGR2 and TGFB2 (p = 0.015). Worse survival outcomes in pbDMG patients when comparing high versus low TGFB2 levels in the context of low IFNGR2 levels suggest that the abrogation of the TGFB2 mRNA expression in the immunologically cold tumor microenvironment can be used to treat pbDMG patients. Furthermore, pbDMG patients with low levels of JAK1 or STAT1 mRNA expression in combination with high levels of TGFB2 also exhibited poor OS outcomes, suggesting that the inclusion of (interferon-gamma) IFN-γ to stimulate and activate JAK1 and STAT1 in anti-tumor APC cells present the brainstem TME can enhance the effect of the TGFB2 blockade. [ABSTRACT FROM AUTHOR]

Atopic dermatitis is a chronic inflammatory dermatosis characterized by pruritic, scaly, erythematous lesions. Its incidence varies but is estimated to be approximately 20% in children and between 7 and 14% in adults, with variation amongst countries. It is a multifactorial condition, with a complex interplay between genetic, immunological, and environmental factors. Research into the inflammatory response has identified new therapeutic targets that work to reduce inflammation and subsequently reduce flares. This study explores existing therapeutic agents for atopic dermatitis as well as newer therapies such as biologics and small molecules, drawing upon each agent’s mechanism of action, relevant landmark clinical trials, efficacy, and safety profile. Current therapies include emollients, corticosteroids, cyclosporine A, calcineurin inhibitors, phototherapy, and methotrexate. Biologics described include dupilumab, tralokinumab, lebrikizumab, nemolizumab, and rocatinlimab. Small molecules inhibitors include Janus kinase inhibitors, phosphodiesterase 4 inhibitors, transient receptor potential vanilloid subfamily V member 1 antagonist, and aryl hydrocarbon receptor antagonist.

We have recently shown that IFNγ, produced during cancer therapy, induces expression of the Bcl3 proto‐oncogene in ovarian cancer (OC) cells, resulting in their increased proliferation, migration, and invasion, but the mechanisms are unknown. Here, we demonstrate that the IFNγ‐induced Bcl3 expression is dependent on JAK1 and STAT1 signaling, and on p65 NFκB. Furthermore, the IFNγ‐induced Bcl3 expression is associated with an increased occupancy of Ser‐727 phosphorylated STAT1 and acetylated histone H3 at the Bcl3 promoter. Our data indicate that Bcl3 promotes expression of the pro‐inflammatory chemokine interleukin‐8 (IL‐8) in OC cells. These findings identify Bcl3 as a novel target of IFNγ/JAK1/STAT1 signaling and suggest that targeting the JAK1/STAT1 pathway may suppress IFNγ‐induced Bcl3 expression in OC.

Abrocitinib stands as a targeted therapy, functioning as an inhibitor of Janus kinase (JAK) 1. This pharmaceutical advancement has been meticulously crafted to address the challenges of moderate to severe atopic dermatitis (AD), a prevalent skin ailment in developed nations. Introduced in 2022, Abrocitinib emerged as a cutting-edge addition to its therapeutic category, gaining approval for utilization within the United States. Diverging from its predecessors in the realm of moderate to severe AD treatment, Abrocitinib distinguishes itself through its heightened specificity. Moreover, its tablet formulation facilitates straightforward administration, offering diverse dosage options. An additional noteworthy feature is its applicability to individuals aged 12 and above, making it an option for alleviating symptoms in this demographic. Within this comprehensive assessment, key aspects such as the biological target of the drug, developmental strategies, mode of operation, pharmacokinetics, pharmacodynamics, clinical trial insights, contraindications, potential interactions with other medications, and adverse reactions are examined. In light of the overarching perspective and available clinical evidence, Abrocitinib emerges as a promising orally bioavailable therapeutic, authorized for treating AD. Notably, it gained its initial approval in Japan for patients aged 12 years and older, marking a significant advancement in the realm of dermatological care.

Simple Summary: Cancer is caused by changes in DNA called mutations that alter the way proteins work. We know that RAS proteins are one of the most commonly mutated proteins in cancer cells. These proteins work like a light switch and mutant RAS remain in the ON position sending signals to the cell to keep dividing when they should not. Until recently, it was thought that all RAS mutations were equal, but differences among these mutants have been identified. Here we used a technique called proteomics to decipher the differences among RAS mutants. We find that each mutant binds a different set of proteins and can regulate different signals. We also find that a clinically approved drug that inhibits one RAS mutant regulates the interaction of RAS proteins with other proteins. Our findings extend our knowledge of how the RAS mutants work, which can potentially be used to improve cancer treatments. RAS proteins are key regulators of cell signalling and control different cell functions including cell proliferation, differentiation, and cell death. Point mutations in the genes of this family are common, particularly in KRAS. These mutations were thought to cause the constitutive activation of KRAS, but recent findings showed that some mutants can cycle between active and inactive states. This observation, together with the development of covalent KRASG12C inhibitors, has led to the arrival of KRAS inhibitors in the clinic. However, most patients develop resistance to these targeted therapies, and we lack effective treatments for other KRAS mutants. To accelerate the development of RAS targeting therapies, we need to fully characterise the molecular mechanisms governing KRAS signalling networks and determine what differentiates the signalling downstream of the KRAS mutants. Here we have used affinity purification mass-spectrometry proteomics to characterise the interactome of KRAS wild-type and three KRAS mutants. Bioinformatic analysis associated with experimental validation allows us to map the signalling network mediated by the different KRAS proteins. Using this approach, we characterised how the interactome of KRAS wild-type and mutants is regulated by the clinically approved KRASG12C inhibitor Sotorasib. In addition, we identified novel crosstalks between KRAS and its effector pathways including the AKT and JAK-STAT signalling modules. [ABSTRACT FROM AUTHOR]

We have recently shown that IFNγ, produced during cancer therapy, induces expression of the Bcl3 proto‐oncogene in ovarian cancer (OC) cells, resulting in their increased proliferation, migration, and invasion, but the mechanisms are unknown. Here, we demonstrate that the IFNγ‐induced Bcl3 expression is dependent on JAK1 and STAT1 signaling, and on p65 NFκB. Furthermore, the IFNγ‐induced Bcl3 expression is associated with an increased occupancy of Ser‐727 phosphorylated STAT1 and acetylated histone H3 at the Bcl3 promoter. Our data indicate that Bcl3 promotes expression of the pro‐inflammatory chemokine interleukin‐8 (IL‐8) in OC cells. These findings identify Bcl3 as a novel target of IFNγ/JAK1/STAT1 signaling and suggest that targeting the JAK1/STAT1 pathway may suppress IFNγ‐induced Bcl3 expression in OC. [ABSTRACT FROM AUTHOR]

Simple Summary: Our study aimed to stain a cellular pathway that is a potential target of drugs to treat allergies. In our study, we took skin samples from dogs allergic to dust, before and after exposure to dust mites, and stained those samples for this pathway. We found that this pathway was present in skin cells and that exposure to the dust mites changed how this pathway was expressed. These results confirm that this pathway plays a role in the course of allergic responses and that topical creams targeting this pathway can be promising to treat allergic skin disease. Janus kinase (JAK) pathways have emerged as targets of treatment, yet localization and expression of JAK1 and JAK3 in canine atopic skin have not been studied. This study aimed to compare the localization and expression of JAK1 and JAK3 in the skin of atopic dogs before and after allergen exposure. Skin biopsies taken from atopic beagles sensitized to house dust mites (HDM) before (D0) and after four weeks (D28) of allergen exposure were stained. Staining was subjectively scored by examiners unaware of the source of the slides. Image J was used for the semiquantitative assessment of staining intensity. JAK1 and JAK3 staining was epidermal and dermal. JAK1 staining was cytoplasmic, primarily found in basal keratinocytes and dermal cells, while JAK 3 was nuclear (all epidermal levels and on dermal inflammatory cells). Epidermal thickness was significantly higher on D28 than on D0 (p < 0.0001). For JAK1, epidermal staining divided by epithelial thickness was significantly lower on D28 (p = 0.0002) compared to D0. For JAK3 staining, intensity in the dermis was significantly higher on D28 (p = 0.0405) compared to D0. We conclude that decreased expression of JAK1 in the epidermis and increased expression of JAK3 in the dermis of atopic dogs occur after allergen exposure. [ABSTRACT FROM AUTHOR]

Dysregulation of vitamin D receptor (VDR) is implicated in chronic obstructive pulmonary disease. However, whether VDR dysregulation contributes to the development of pulmonary fibrosis remains largely unknown. Analysis of bulk and single-cell RNA profiling datasets revealed VDR upregulation in lung fibroblasts from patients with pulmonary fibrosis or fibrotic mice, which was validated in lung fibroblasts from bleomycin-exposed mice and bleomycin-treated fibroblasts. Stable VDR knockdown promoted, whereas the VDR agonist paricalcitol suppressed lung fibroblast proliferation and activation. Gene set enrichment analysis (GSEA) showed that the JAK/STAT pathway and unfolded protein response (UPR), a process related to endoplasmic reticulum (ER) stress, were enriched in lung fibroblasts of fibrotic lungs. Stable VDR knockdown stimulated, but paricalcitol suppressed ER stress and JAK1/STAT3 activation in lung fibroblasts. The STAT3 inhibitor blocked bleomycin- or stable VDR knockdown-induced ER stress. Paricalcitol inhibited the bleomycin-induced enrichment of STAT3 to the ATF6 promoter, thereby suppressing ATF6 expression in fibroblasts. Paricalcitol or intrapulmonary VDR overexpression inactivated JAK1/STAT3 and suppressed ER stress in bleomycin-treated mice, thus resulting in the inhibition of fibroblast proliferation and activation. Collectively, this study suggests that fibroblast VDR upregulation may be a self-protective response to limit fibroblast proliferation and activation during pulmonary fibrosis by suppressing the JAK1/STAT3/ER stress pathway. [ABSTRACT FROM AUTHOR]

An ethnobotanical investigation was carried out in Gafargaon sub-district (upazila) under Mymensingh district, Bangladesh that unveiled a total of 79 medicinal plant species under 74 genera and 46 families which were used to treat various ailments through 106 formularies. In addition, molecular docking and dynamics simulation studies were performed based on ethnobotanical outcome for the first time in Bangladesh to unveil potential drug candidates. The study revealed that most of the species used for primary healthcare were herbs (44.3%) followed by trees (36.7%), shrubs (10.2%) and climbers (8.8%). Leaves were found to be the most frequently used part (34%) compared to other plant parts. Factor of informant consensus values ranged from 0.975 to 0.984 and the highest value was recorded for respiratory tract disorders (0.984). Maximum number of taxa was unraveled to treat digestive and gastrointestinal disorders. Fidelity level varied from 41.2 to 100%, where 11 species showed 100% fidelity, and the citation frequency was found above 70% for 15 different ailments. Molecular docking study exposed 60% Stephania japonica phytocompounds scoring higher than the control drug Ibuprofen (-7.0 kcal/mol) targeting rheumatoid arthritis. The phytocompounds Oxostephanine, Trilobine and Epistephanine were identified as lead drug candidates with binding affinity of -9.7, -8.7 and -8.6 kcal/mol, respectively. Molecular interactions of these compounds were found significant to identify potential drug surface hotspots. Molecular dynamics simulation shed light on regional flexibility profiles and unraveled notable structural stability of the top three phytocompounds. The present study would offer foundational data for identifying potential bioactive compounds that could be utilized in novel drug discovery efforts. [ABSTRACT FROM AUTHOR]

Abstract Background Loss-of-function (LOF) mutations of JAK1, a member of the JAK kinase family, were frequently observed in EC, indicating that JAK1 may act as a tumor suppressor, at least in EC. However, the mechanism of JAK1 mediated regulation of tumorigenesis remains poorly understood. Methods The genetic alterations of JAK1 in EC using latest sequencing dataset of EC deposited in TCGA database. The RNA-Seq dataset of EC and normal endometrial tissues from TCGA cohort was analyzed. The expression of JAK1 in EC and normal endometrial tissues were investigated using immunohistochemistry. The expression levels of genes in endometrial cancer cells were detected by quantitative reverse transcription-PCR (RT-qPCR) and western blotting. JAK1 protein was efficiently depleted by the two shRNAs. HIF1/2-α protein was efficiently depleted by siRNAs. JAK1 overexpressed EC cells were generated by an expressing plasmid. The proliferation and migration ability of cancer cells were evaluated by CCK8, colony formation assays and transwell assays. The global transcriptomic changes in JAK1-depleted KLE cells were investigated using RNA-Seq. Gene Ontology (GO) Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were used to identify the most significant pathways that were altered in JAK1-depleted KLE cells. The physical association between HIF-1/2α and JAK1 using co-immunoprecipitation (co-IP) assays. Results In the present study, we found that JAK1 was frequently mutated and downregulated in EC. JAK1 knockdown promotes EC cell proliferation and migration. JAK1 overexpression reduces EC cell proliferation and migration. We examined the transcriptional profiling changes in JAK1-depleted EC cells and unexpectedly found that the hypoxia inducible factor (HIF) pathway was activated. Mechanistically, JAK1 interacts with HIF-1/2α, and reduces HIF1/2-α protein expression under hypoxia. HIF-1/2α knockdown reverses the JAK1 knockdown–induced growth and migration of EC cells under hypoxia. JAK1 knockdown or pharmacological inhibition of JAK1 kinase activity by Ruxolitinib upregulates transcription of HIF target genes under hypoxia. JAK1 overexpression downregulates transcription of HIF target genes under hypoxia. Conclusions These findings provide novel insights into the functional link between JAK1 LOF mutations and abnormal HIF pathway activation in EC and suggest that pharmacological inhibition of HIF1/2 represents a promising therapeutic strategy targeting JAK1-mutated ECs. Video Abstract

Janus kinase (JAK)/signal transducer and activator of transcription signaling (STAT) has been implicated in the pathophysiology of hidradenitis suppurativa (HS). This study evaluated treatment-related transcriptomic and proteomic changes in patients with moderate-to-severe HS treated with the investigational oral JAK1-selective inhibitor povorcitinib (INCB054707) in two phase 2 trials. Lesional skin punch biopsies (baseline and Week 8) were taken from active HS lesions of patients receiving povorcitinib (15 or 30 mg) once daily (QD) or a placebo. RNA-seq and gene set enrichment analyses were used to evaluate the effects of povorcitinib on differential gene expression among previously reported gene signatures from HS and wounded skin. The number of differentially expressed genes was the greatest in the 30 mg povorcitinib QD dose group, consistent with the published efficacy results. Notably, the genes impacted reflected JAK/STAT signaling transcripts downstream of TNF-α signaling, or those regulated by TGF-β. Proteomic analyses were conducted on blood samples obtained at baseline and Weeks 4 and 8 from patients receiving povorcitinib (15, 30, 60, or 90 mg) QD or placebo. Povorcitinib was associated with transcriptomic downregulation of multiple HS and inflammatory signaling markers as well as the reversal of gene expression previously associated with HS lesional and wounded skin. Povorcitinib also demonstrated dose-dependent modulation of several proteins implicated in HS pathophysiology, with changes observed by Week 4. The reversal of HS lesional gene signatures and rapid, dose-dependent protein regulation highlight the potential of JAK1 inhibition to modulate underlying disease pathology in HS. [ABSTRACT FROM AUTHOR]

Overactive Janus kinases (JAKs) are known to drive leukemia, making them well-suited targets for treatment. We sought to identify new JAK-activating mutations and instead found a JAK1-inactivating pseudokinase mutation, V666G. In contrast to other pseudokinase mutations that canonically lead to an active kinase, the JAK1 V666G mutation led to under-activation seen by reduced phosphorylation. To understand the functional role of JAK1 V666G in modifying kinase activity we investigated its influence on other JAK kinases and within the Interleukin-2 pathway. JAK1 V666G not only inhibited its own activity, but its presence could inhibit other JAK kinases. These findings provide new insights into the potential of JAK1 pseudokinase to modulate its own activity, as well as of other JAK kinases. Thus, the features of the JAK1 V666 region in modifying JAK kinases can be exploited to allosterically inhibit overactive JAKs. [ABSTRACT FROM AUTHOR]

ABSTRACT African swine fever virus (ASFV) causes acute hemorrhagic infectious disease in pigs. The ASFV genome encodes various proteins that enable the virus to escape innate immunity; however, the underlying mechanisms are poorly understood. The present study found that ASFV MGF-360-10L significantly inhibits interferon (IFN)-β-triggered STAT1/2 promoter activation and the production of downstream IFN-stimulated genes (ISGs). ASFV MGF-360-10L deletion (ASFV-Δ10L) replication was impaired compared with the parental ASFV CN/GS/2018 strain, and more ISGs were induced by the ASFV-Δ10L in porcine alveolar macrophages in vitro. We found that MGF-360-10L mainly targets JAK1 and mediates its degradation in a dose-dependent manner. Meanwhile, MGF-360-10L also mediates the K48-linked ubiquitination of JAK1 at lysine residues 245 and 269 by recruiting the E3 ubiquitin ligase HERC5 (HECT and RLD domain-containing E3 ubiquitin protein ligase 5). The virulence of ASFV-Δ10L was significantly lower than that of the parental strain in vivo, which indicates that MGF-360-10L is a novel virulence factor of ASFV. Our findings elaborate the novel mechanism of MGF-360-10L on the STAT1/2 signaling pathway, expanding our understanding of the inhibition of host innate immunity by ASFV-encoded proteins and providing novel insights that could contribute to the development of African swine fever vaccines. IMPORTANCE African swine fever outbreaks remain a concern in some areas. There is no effective drug or commercial vaccine to prevent African swine fever virus (ASFV) infection. In the present study, we found that overexpression of MGF-360-10L strongly inhibited the interferon (IFN)-β-induced STAT1/2 signaling pathway and the production of IFN-stimulated genes (ISGs). Furthermore, we demonstrated that MGF-360-10L mediates the degradation and K48-linked ubiquitination of JAK1 by recruiting the E3 ubiquitin ligase HERC5. The virulence of ASFV with MGF-360-10L deletion was significantly less than parental ASFV CN/GS/2018. Our study identified a new virulence factor and revealed a novel mechanism by which MGF-360-10L inhibits the immune response, thus providing new insights into the vaccination strategies against ASFV.

Background: JAK1 is a signaling molecule downstream of cytokine receptors, including IL-4 receptor α. Abrocitinib is an oral JAK1 inhibitor; it is a safe and effective US Food and Drug Administration–approved treatment for adults with moderate-to-severe atopic dermatitis. Objective: Our objective was to investigate the effect of abrocitinib on basophil activation and T-cell activation in patients with peanut allergy to determine the potential for use of JAK1 inhibitors as a monotherapy or an adjuvant to peanut oral immunotherapy. Methods: Basophil activation in whole blood was measured by detection of CD63 expression using flow cytometry. Activation of CD4+ effector and regulatory T cells was determined by the upregulation of CD154 and CD137, respectively, on anti-CD3/CD28– or peanut-stimulated PBMCs. For the quantification of peanut-induced cytokines, PBMCs were stimulated with peanut for 5 days before harvesting supernatant. Results: Abrocitinib decreased the allergen-specific activation of basophils in response to peanut. We showed suppression of effector T-cell activation when stimulated by CD3/CD28 beads in the presence of 10 ng of abrocitinib, whereas activation of regulatory T-cell populations was preserved in the presence of abrocitinib. Abrocitinib induced statistically significant dose-dependent inhibition in IL-5, IL-13, IL-10, IL-9, and TNF-α in the presence of peanut stimulation. Conclusion: These results support our hypothesis that JAK1 inhibition decreases basophil activation and TH2 cytokine signaling, reducing in vitro allergic responses in subjects with peanut allergy. Abrocitinib may be an effective adjunctive immune modulator in conjunction with peanut oral immunotherapy or as a monotherapy for individuals with food allergy.

Abstract Background Metastatic breast cancer (MBC) is a major health problem worldwide. Some patients improve on tamoxifen and others do not respond to treatment. Therefore, the aim of the current study is to assess genetic aberrations in the Her2/EGFR-PDGFR pathway associated with tamoxifen response in MBC patients. Methods This is a retrospective cohort study, including 157 hormone receptors positive, locally recurrent inoperable and/or MBC patients on tamoxifen treatment. Patients were categorized into 78 (49.7%) tamoxifen responders and 79 (50.3%) tamoxifen non-responder patients. Genetic aberrations of 84 genes involved in the Her2/EGFR-PDGFR pathway were assessed in the tumor tissue samples obtained from the patients using SA-Bioscience assay. The identified panel was correlated to patients’ response to treatment, to detect the differentially expressed genes in tamoxifen responders and non-responders. Results One hundred twenty-three (78.3%) patients were estrogen receptor (ER) and progesterone receptor (PR) positive, 108 (68.8%) were ER only positive, and 78 (49.7%) were PR only positive. There were 56 genes overexpressed in the refractory group compared to responders. However, only five out of these 56 genes, Janus kinase 1 (JAK1), collagen type I alpha 1 (COL1A1), GRB2-associated binding protein 1 (GAB1), fibronectin-1 (FN1), and MAP kinase-interacting serine/threonine-protein kinase (MKNK1), showed statistical significance between the two groups. Patients with bone metastasis showed a better response to treatment compared to those with metastatic deposits in other sites such as visceral metastasis (P

Abrocitinib is a JAK1 selective inhibitor recently approved for the treatment of moderate-to-severe atopic dermatitis in adults. It has demonstrated efficacy and safety in several clinical trials, both in children and adults, in monotherapy, and compared with dupilumab. The expected EASI-75 response rate estimates at week 12 are 62.9% (95% CrI 42.5–79.9%) for abrocitinib 200 mg and 43.0% (95% CrI 24.8–64.0%) for abrocitinib 100 mg. Abrocitinib has shown a faster effect than dupilumab as regards early alleviation of itch. Because of the incomplete target selectivity of JAK inhibitors, when abrocitinib treatment is considered, laboratory screening is necessary, latent tuberculosis must be screened for, active infections are a contraindication, and special caution must be exerted in treating elderly patients and those predisposed to thromboembolic events. Even though recent meta-analyses of clinical trials have not shown that atopic dermatitis, or its treatment with JAK inhibitors or dupilumab, modify the risk of deep venous thrombosis or pulmonary embolism, long-term follow-up studies will better define the safety profile of abrocitinib. [ABSTRACT FROM AUTHOR]

Background/Aim: Signal transducer and activator of transcription 3 (STAT3), Janus Kinase 1 (JAK1), extracellular signal-regulated kinase (ERK), and protein kinase B (AKT) are essential for malignant transformation and progression in colorectal cancer (CRC) and can be considered as targets for therapeutic interventions. Hyperforin, an active constituent from Hypericum perforatum, has been reported to inhibit inflammation. However, whether hyperforin may suppress CRC progression via inactivation of JAK/STAT3, ERK or AKT signaling remains unclear. Materials and Methods: Human CRC cells were used to identify the treatment efficacy of hyperforin and its underlying mechanisms of action by MTT, flow cytometry, wound healing, and western blotting assays. Results: Hyperforin not only induced cytotoxicity, extrinsic/intrinsic apoptosis signaling, but also suppressed the invasion/migration ability of CRC. The phosphorylation of STAT3, JAK1, ERK and AKT was found to be decreased by hyperforin. Conclusion: Hyperforin inactivates multiple oncogenic kinases and induces apoptosis signaling in CRC cells. [ABSTRACT FROM AUTHOR]

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with limited survival. Janus kinases (JAKs), tyrosine kinases that transduce cytokine-mediated signals, are known to be involved, but their specific roles in lung fibrosis are not well defined. In this study, the interactions between JAK1/signal transducers and activators of transcription (STAT)3 signaling and transforming growth factor-beta (TGF-b)-induced fibroblast responses were investigated using both pharmacological and siRNA approaches in human normal and IPF-derived lung fibroblasts. We found that JAK1 directly interacts with the TGF-b receptor I subunit (TbRI), and silencing JAK1 promotes myofibroblast transdifferentiation. However, the suppression of JAK1 signaling in vitro and in vivo using an inhibitor (upadacitinib) did not alter lung fibroblast activation or fibrosis development. STAT3 was constitutively active in cultured primary lung fibroblasts; this STAT3 activation required JAK1 and repressed myofibroblast transdifferentiation. Loss of phosphorylated STAT3 following transcriptional JAK1 silencing promoted myofibroblast transdifferentiation. In contrast, transcriptional silencing of unphosphorylated STAT3 suppressed TGF-b signaling, decreased SMAD3 activation, and reduced myofibroblast transdifferentiation and ECM production. Taken together, these observations support a role for JAK1/STAT3 as a direct regulator of TGF-b signaling in lung fibroblasts. Modulation of JAK1/STAT3 signaling in lung fibroblasts represents a noncanonical approach to regulating TGF-b-induced fibrosis and suggests the potential for a novel approach to treat pulmonary fibrosis. [ABSTRACT FROM AUTHOR]

Abstract Background SARS-CoV-2 is the causative agent of COVID-19. Overproduction and release of proinflammatory cytokines are the underlying cause of severe COVID-19. Treatment of this condition with JAK inhibitors is a double-edged sword, which might result in the suppression of proinflammatory cytokine storm and the concurrent enhancement of viral infection, since JAK signaling is essential for host antiviral response. Improving the current JAK inhibitor therapy requires a detailed molecular analysis on how SARS-CoV-2 modulates interferon (IFN)-induced activation of JAK-STAT signaling. Results In this study, we focused on the molecular mechanism by which SARS-CoV-2 NSP13 helicase suppresses IFN signaling. Expression of SARS-CoV-2 NSP13 alleviated transcriptional activity driven by type I and type II IFN-responsive enhancer elements. It also prevented nuclear translocation of STAT1 and STAT2. The suppression of NSP13 on IFN signaling occurred at the step of STAT1 phosphorylation. Nucleic acid binding-defective mutant K345A K347A and NTPase-deficient mutant E375A of NSP13 were found to have largely lost the ability to suppress IFN-β-induced STAT1 phosphorylation and transcriptional activation, indicating the requirement of the helicase activity for NSP13-mediated inhibition of STAT1 phosphorylation. NSP13 did not interact with JAK1 nor prevent STAT1-JAK1 complex formation. Mechanistically, NSP13 interacted with STAT1 to prevent JAK1 kinase from phosphorylating STAT1. Conclusion SARS-CoV-2 NSP13 helicase broadly suppresses IFN signaling by targeting JAK1 phosphorylation of STAT1.

Vascular endothelial cell (VEC) dysfunction is associated with the development of coronary heart disease (CHD). Long intergenic non-protein coding RNA 926 (LINC00926), a kind of long noncoding RNA (lncRNA), has been found to be abnormally expressed in CHD patients. However, the biological role of LINC00926 has not been reported. In our research, we intended to explore the regulatory mechanism of LINC00926 in hypoxia-exposed HUVEC cells (HUVECs). In our in vitro study, HUVECs were exposed under hypoxic conditions (5% O2) for 24 h. RT-qPCR and Western blotting assay were used to detect the mRNA and protein levels. CCK-8 assay, flow cytometry, transwell assay and in vitro angiogenesis assay were performed to measure cell proliferation, apoptosis, migration and tube formation, respectively. Bioinformatics analysis was applied to predict the target of LINC00926 and miR-3194-5p, which was verified by dual-luciferase reporter assays. The results showed that LINC00926 was highly expressed in CHD patients and hypoxia-exposed HUVECs. LINC00926 overexpression suppressed cell proliferation, migration and tube formation and increased cell apoptosis. MiR-3194-5p was a target of LINC00926 and can target binding to JAK1 3’UTR. LINC00926 could up-regulate JAK1 and p-STAT3 levels via miR-3194-5p. In addition, overexpressed LINC00926 suppressed cell proliferation, migration and tube formation and increased cell apoptosis via miR-3194-5p/JAK1/STAT3 axis. In summary, LINC00926 aggravated endothelial cell dysfunction via miR-3194-5p regulating JAK1/STAT3 signaling pathway in hypoxia-exposed HUVECs.

Background: Loss-of-function (LOF) mutations of JAK1, a member of the JAK kinase family, were frequently observed in EC, indicating that JAK1 may act as a tumor suppressor, at least in EC. However, the mechanism of JAK1 mediated regulation of tumorigenesis remains poorly understood. Methods: The genetic alterations of JAK1 in EC using latest sequencing dataset of EC deposited in TCGA database. The RNA-Seq dataset of EC and normal endometrial tissues from TCGA cohort was analyzed. The expression of JAK1 in EC and normal endometrial tissues were investigated using immunohistochemistry. The expression levels of genes in endometrial cancer cells were detected by quantitative reverse transcription-PCR (RT-qPCR) and western blotting. JAK1 protein was efficiently depleted by the two shRNAs. HIF1/2-α protein was efficiently depleted by siRNAs. JAK1 overexpressed EC cells were generated by an expressing plasmid. The proliferation and migration ability of cancer cells were evaluated by CCK8, colony formation assays and transwell assays. The global transcriptomic changes in JAK1-depleted KLE cells were investigated using RNA-Seq. Gene Ontology (GO) Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were used to identify the most significant pathways that were altered in JAK1-depleted KLE cells. The physical association between HIF-1/2α and JAK1 using co-immunoprecipitation (co-IP) assays. Results: In the present study, we found that JAK1 was frequently mutated and downregulated in EC. JAK1 knockdown promotes EC cell proliferation and migration. JAK1 overexpression reduces EC cell proliferation and migration. We examined the transcriptional profiling changes in JAK1-depleted EC cells and unexpectedly found that the hypoxia inducible factor (HIF) pathway was activated. Mechanistically, JAK1 interacts with HIF-1/2α, and reduces HIF1/2-α protein expression under hypoxia. HIF-1/2α knockdown reverses the JAK1 knockdown–induced growth and migration of EC cells under hypoxia. JAK1 knockdown or pharmacological inhibition of JAK1 kinase activity by Ruxolitinib upregulates transcription of HIF target genes under hypoxia. JAK1 overexpression downregulates transcription of HIF target genes under hypoxia. Conclusions: These findings provide novel insights into the functional link between JAK1 LOF mutations and abnormal HIF pathway activation in EC and suggest that pharmacological inhibition of HIF1/2 represents a promising therapeutic strategy targeting JAK1-mutated ECs. 3W7_hN6trihWN8_decuxdB Video Abstract [ABSTRACT FROM AUTHOR]

Objective: We aimed to explore and verify the mechanism underlying the action of the active ingredients of Paeoniae Radix Alba (PRA) in the treatment of rheumatoid arthritis (RA). Methods: The protein targets of PRA's six active ingredients and RA were identified. Then, the intersection of the two groups was studied. The drug--target network was constructed, visualized, and analyzed by Cytoscape software. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment were performed to analyze these genes. Furthermore, we validated our predictions of the potential targets through a docking study. Finally, the anti-inflammatory effect of Palbinone (PB), one of the active ingredients of PRA, was tested by conducting in vitro and in vivo studies. Results: Six active ingredients of PRA were identified, and 103 overlapping genes were discovered. Functional enrichment analysis indicated that the genes are mostly enriched in IL-17 signaling pathway, Th17 cell differentiation, and the FoxO, ErbB, and TNF signaling pathways. 10 hub genes and two gene cluster modules were identified by Cytoscape. Molecular docking analysis proved that PB was able to bind to the ATP binding site of Janus kinase (JAK)1, thereby acting as a potential inhibitor of JAK1. In vitro and in vivo studies demonstrated that PB exerts its anti-inflammatory role via the inhibition of JAK1. Conclusion: We constructed a multitarget pharmacological network of PRA in RA treatment. PB, one of the active compounds of PRA, was demonstrated to be a promising inhibitor of JAK1. [ABSTRACT FROM AUTHOR]

Canine gastrointestinal lymphoma is known to be of T-cell origin in most cases, but the molecular biological aberrations have not been clarified. In human intestinal T-cell lymphoma, the mutations in the genes associated with Janus kinase/signal transducer and activator of transcription (JAK-STAT) pathway have been frequently observed. In this study, the gene mutations were investigated in 31 dogs with large cell gastrointestinal lymphoma (LCGIL) by focusing on the genes involved in JAK-STAT pathway. Next-generation sequencing analysis to examine the mutations in STAT3, STAT5B, and JAK1 genes throughout the exon regions revealed the mutations in STAT3 gene in two dogs and JAK1 gene in one dog. In conclusion, this study could not indicate the associations of gene mutations in JAK-STAT pathway with LCGIL in most canine cases.

Abstract Background Janus-activated kinase-1 (JAK1) plays a crucial role in many aspects of cell proliferation, differentiation, apoptosis and immune regulation. However, correlations of JAK1 with prognosis and immune infiltration in NSCLC have not been documented. Methods We analyzed the relationship between JAK1 expression and NSCLC prognosis and immune infiltration using multiple public databases. Results JAK1 expression was significantly decreased in NSCLC compared with that in paired normal tissues. JAK1 overexpression indicated a favourable prognosis in NSCLC. In subgroup analysis, high JAK1 expression was associated with a preferable prognosis in lung adenocarcinoma (OS: HR, 0.74, 95% CI from 0.58 to 0.95, log-rank P = 0.017), not squamous cell carcinoma. In addition, data from Kaplan–Meier plotter revealed that JAK1 overexpression was associated with a preferable prognosis in male and stage N2 patients and patients without distant metastasis. Notably, increased levels of JAK1 expression were associated with an undesirable prognosis in patients with stage 1 (OS: HR, 1.46, 95% CI from 1.06 to 2.00, P = 0.02) and without lymph node metastasis (PFS: HR, 2.18, 95% CI from 1.06 to 4.46, P = 0.029), which suggests that early-stage NSCLC patients with JAK1 overexpression may have a bleak prognosis. Moreover, multiple immune infiltration cells, including NK cells, CD8 + T and CD4 + T cells, B cells, macrophages, neutrophils, and dendritic cells (DCs), in NSCLC were positively correlated with JAK1 expression. Furthermore, diverse immune markers are associated with JAK1 expression. Conclusions JAK1 overexpression exhibited superior prognosis and immune infiltration in NSCLC.

PurposeJanus kinase-1 (JAK1) tyrosine kinase mediates signaling from multiple cytokine receptors, including interferon alpha/beta and gamma (IFN-α/β and IFN-γ), which are important for viral and mycobacterial protection respectively. We previously reported autosomal recessive (AR) hypomorphic JAK1 mutations in a patient with recurrent atypical mycobacterial infections and relatively minor viral infections. This study tests the impact of partial JAK1 deficiency on cellular responses to IFNs and pathogen control.MethodsWe investigated the role of partial JAK1 deficiency using patient cells and cell models generated with lentiviral vectors expressing shRNA.ResultsPartial JAK1 deficiency impairs IFN-γ-dependent responses in multiple cell types including THP-1 macrophages, Epstein-Barr Virus (EBV)-transformed B cells and primary dermal fibroblasts. In THP-1 myeloid cells, partial JAK1 deficiency reduced phagosome acidification and apoptosis and resulted in defective control of mycobacterial infection with enhanced intracellular survival. Although both EBV-B cells and primary dermal fibroblasts with partial JAK1 deficiency demonstrate reduced IFN-α responses, control of viral infection was impaired only in patient EBV-B cells and surprisingly intact in patient primary dermal fibroblasts.ConclusionOur data suggests that partial JAK1 deficiency predominantly affects susceptibility to mycobacterial infection through impact on the IFN-γ responsive pathway in myeloid cells. Susceptibility to viral infections as a result of reduced IFN-α responses is variable depending on cell type. Description of additional patients with inherited JAK1 deficiency will further clarify the spectrum of bacterial and viral susceptibility in this condition. Our results have broader relevance for anticipating infectious complications from the increasing use of selective JAK1 inhibitors.

Janus kinase (JAK) pathways have emerged as targets of treatment, yet localization and expression of JAK1 and JAK3 in canine atopic skin have not been studied. This study aimed to compare the localization and expression of JAK1 and JAK3 in the skin of atopic dogs before and after allergen exposure. Skin biopsies taken from atopic beagles sensitized to house dust mites (HDM) before (D0) and after four weeks (D28) of allergen exposure were stained. Staining was subjectively scored by examiners unaware of the source of the slides. Image J was used for the semiquantitative assessment of staining intensity. JAK1 and JAK3 staining was epidermal and dermal. JAK1 staining was cytoplasmic, primarily found in basal keratinocytes and dermal cells, while JAK 3 was nuclear (all epidermal levels and on dermal inflammatory cells). Epidermal thickness was significantly higher on D28 than on D0 (p < 0.0001). For JAK1, epidermal staining divided by epithelial thickness was significantly lower on D28 (p = 0.0002) compared to D0. For JAK3 staining, intensity in the dermis was significantly higher on D28 (p = 0.0405) compared to D0. We conclude that decreased expression of JAK1 in the epidermis and increased expression of JAK3 in the dermis of atopic dogs occur after allergen exposure.

Dysregulation of vitamin D receptor (VDR) is implicated in chronic obstructive pulmonary disease. However, whether VDR dysregulation contributes to the development of pulmonary fibrosis remains largely unknown. Analysis of bulk and single-cell RNA profiling datasets revealed VDR upregulation in lung fibroblasts from patients with pulmonary fibrosis or fibrotic mice, which was validated in lung fibroblasts from bleomycin-exposed mice and bleomycin-treated fibroblasts. Stable VDR knockdown promoted, whereas the VDR agonist paricalcitol suppressed lung fibroblast proliferation and activation. Gene set enrichment analysis (GSEA) showed that the JAK/STAT pathway and unfolded protein response (UPR), a process related to endoplasmic reticulum (ER) stress, were enriched in lung fibroblasts of fibrotic lungs. Stable VDR knockdown stimulated, but paricalcitol suppressed ER stress and JAK1/STAT3 activation in lung fibroblasts. The STAT3 inhibitor blocked bleomycin- or stable VDR knockdown-induced ER stress. Paricalcitol inhibited the bleomycin-induced enrichment of STAT3 to the ATF6 promoter, thereby suppressing ATF6 expression in fibroblasts. Paricalcitol or intrapulmonary VDR overexpression inactivated JAK1/STAT3 and suppressed ER stress in bleomycin-treated mice, thus resulting in the inhibition of fibroblast proliferation and activation. Collectively, this study suggests that fibroblast VDR upregulation may be a self-protective response to limit fibroblast proliferation and activation during pulmonary fibrosis by suppressing the JAK1/STAT3/ER stress pathway.

Background: The Janus-activated kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathway regulates cutaneous melanoma (CM) development and progression. The JAK1, JAK2, and STAT3 proteins are encoded by polymorphic genes. This study aimed to verify whether singlenucleotide variants (SNVs) in JAK1 (c.1648+1272G>A, c.991-27C>T), JAK2 (c.- 1132G>T, c.-139G>A), and STAT3 (c.*1671T>C, c.-1937C>G) altered the risk, clinicopathological aspects, and survival of CM patients as well as protein activity. Methods: CM patients (N = 248) and controls (N = 274) were enrolled in this study. Genotyping was performed by real-time polymerase chain reaction (PCR), and JAK1, JAK2, and STAT3 expression was assessed by quantitative PCR (qPCR). STAT3 c.-1937C>G SNV was investigated by luciferase, qPCR, western blot, apoptosis, and cell cycle assays in SKMEL-28 cells with CC or GG genotype. Results: Individuals with STAT3 c.*1671TT and c.-1937CC genotypes and TC haplotype of both SNVs were under about 2.0-fold increased risk of CM. Specific JAK1, JAK2, and STAT3 combined genotypes were associated with up to 4.0-fold increased risk of CM. Higher luciferase activity [4,013.34 vs. 2,463.32 arbitrary units (AU); p=0.004], STAT3 expression by qPCR (649.20 vs. 0.03 AU; p = 0.003) and western blot (1.69 vs. 1.16AU; p = 0.01), and percentage of cells in the S phase of the cell cycle (57.54 vs. 30.73%; p = 0.04) were more frequent in SKMEL-28 with STAT3 c.-1937CC than with GG genotype. CM cell line with CC genotype presented higher STAT3 protein levels than the one with GG genotype (1.93 versus 1.27 AU, p = 0.0027). Conclusion: Our data present preliminary evidence that inherited abnormalities in the JAK/STAT pathway can be used to identify individuals at a high risk of CM, who deserve additional attention for tumor prevention and early detection. [ABSTRACT FROM AUTHOR]

Background: Metastatic breast cancer (MBC) is a major health problem worldwide. Some patients improve on tamoxifen and others do not respond to treatment. Therefore, the aim of the current study is to assess genetic aberrations in the Her2/EGFR-PDGFR pathway associated with tamoxifen response in MBC patients. Methods: This is a retrospective cohort study, including 157 hormone receptors positive, locally recurrent inoperable and/or MBC patients on tamoxifen treatment. Patients were categorized into 78 (49.7%) tamoxifen responders and 79 (50.3%) tamoxifen non-responder patients. Genetic aberrations of 84 genes involved in the Her2/EGFR-PDGFR pathway were assessed in the tumor tissue samples obtained from the patients using SA-Bioscience assay. The identified panel was correlated to patients' response to treatment, to detect the differentially expressed genes in tamoxifen responders and non-responders. Results: One hundred twenty-three (78.3%) patients were estrogen receptor (ER) and progesterone receptor (PR) positive, 108 (68.8%) were ER only positive, and 78 (49.7%) were PR only positive. There were 56 genes overexpressed in the refractory group compared to responders. However, only five out of these 56 genes, Janus kinase 1 (JAK1), collagen type I alpha 1 (COL1A1), GRB2-associated binding protein 1 (GAB1), fibronectin-1 (FN1), and MAP kinase-interacting serine/threonine-protein kinase (MKNK1), showed statistical significance between the two groups. Patients with bone metastasis showed a better response to treatment compared to those with metastatic deposits in other sites such as visceral metastasis (P < 0.005). Conclusions: Genetic profiling using simple quantitative real-time polymerase chain reaction (qRT-PCR) protocols could be used to assess response to tamoxifen treatment in MBC patients. According to our data, a five-gene panel in the EGFR pathway (JAK1, COL1A1, GAB1, FN1 and MKNK1) could be used to categorize MBC patients into groups according to treatment response. [ABSTRACT FROM AUTHOR]

Introduction. Peroxiredoxin 6 (Prdx6) is widely expressed in mammalian tissues. Our previous study demonstrated that Prdx6 was expressed in human epididymis, present in human seminal fluid, and in spermatozoa. The protective role of Prdx6 in maintaining the viability and DNA integrity of human spermatozoa was also detected. Here, we demonstrate the potential role and mechanism of Prdx6 in human epididymis epithelial cells (HEECs). Material and methods. Western blotting was used to measure expression levels of key proteins in the Janus kinase//signal transducer and activator of transcription (JAK/STAT) signaling pathway. The malonaldehyde (MDA) levels and antioxidant capacity in HEECs were detected with the commercial kits. Digital gene expression analysis (DGE) was used to identify gene expression patterns in control and Prdx6-interference HEECs. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to validate the DGE findings. Results. Compared to control HEECs, the expression levels of JAK1, STAT1, phosphorylated JAK1 and STAT1 were significantly increased, while the expression level of SOCS3 was significantly decreased in Prdx6-interference HEECs. The MDA level and total antioxidant capacity in Prdx6-interference HEECs were significantly increased and decreased compared to that of control, respectively. DGE analysis identified 589 up-regulated and 314 down-regulated genes (including Prdx6) in Prdx6-interference HEECs. Thirteen significantly different pathways were identified between the two groups, with the majority of genes belonging to the CCL, CXCL, IL, and IFIT family of proteins and were related to immunity. In particular, the expression levels of IL6, IL6ST, and eighteen IFN-related genes were significantly increased in Prdx6-interference HEECs compared to control HEECs. Conclusions. We found that reduced Prdx6 expression induced higher ROS levels in HEECs, which resulted in the activation of the IL-6 receptor and IFNγ expression to induce the JAK1/STAT1 signaling pathway. (Folia Histochemica et Cytobiologica 2022, Vol. 60, No. 3, 226-236). [ABSTRACT FROM AUTHOR]

Sandfly fever viruses are emerging Phleboviruses typically causing mild febrile illness. Some strains, however, can cause severe and occasionally fatal neuro-invasive disease. Like most viruses, Phleboviruses have devised various strategies to inhibit the type I interferon (IFN) response to support a productive infection. Still, most of the strategies identified so far focus on inhibiting the sensing arm of the IFN response. In contrast, the effect of sandfly virus infection on signaling from the IFN receptor is less characterized. Therefore, we tested the effect of sandfly fever virus Naples (SFNV) and Sicily (SFSV) infection on IFN signaling. We found that infection with either of these viruses inhibits signaling from the IFN receptor by inhibiting STAT1 phosphorylation and nuclear localization. We show that the viral nonstructural protein NSs mediates these effects, but only NSs from SFNV was found to interact with STAT1 directly. Thus, we tested the upstream IFN signaling components and found that Janus kinase 1 (Jak1) phosphorylation is also impaired by infection. Furthermore, the NSs proteins from both viruses directly interacted with Jak1. Last, we show that IFN inhibition by SFNV and SFSV is most likely downstream of the IFN receptor at the Jak1 level. Overall, our results reveal the multiple strategies used by these related viruses to overcome host defenses. [ABSTRACT FROM AUTHOR]

JAK1 is a critical effector of pro-inflammatory cytokine signaling and plays important roles in immune function, while abnormal JAK1 activity has been linked to immunological and neoplastic diseases. Specific functions of JAK1 in the context of hematopoiesis, and specifically within hematopoietic stem cells (HSCs), have not clearly been delineated. Here, we show that conditional Jak1 loss in HSCs reduces their self-renewal and markedly alters lymphoid/myeloid differentiation in vivo. Jak1-deficient HSCs exhibit decreased competitiveness in vivo and are unable to rescue hematopoiesis in the setting of myelosuppression. They exhibit increased quiescence, an inability to enter the cell cycle in response to hematopoietic stress, and a marked reduction in cytokine sensing, including in response to type I interferons and IL-3. Moreover, Jak1 loss is not fully rescued by expression of a constitutively active Jak2 allele. Together, these data highlight an essential role for Jak1 in HSC homeostasis and stress responses.

BackgroundThe Janus-activated kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathway regulates cutaneous melanoma (CM) development and progression. The JAK1, JAK2, and STAT3 proteins are encoded by polymorphic genes. This study aimed to verify whether single-nucleotide variants (SNVs) in JAK1 (c.1648+1272G>A, c.991-27C>T), JAK2 (c.-1132G>T, c.-139G>A), and STAT3 (c.*1671T>C, c.-1937C>G) altered the risk, clinicopathological aspects, and survival of CM patients as well as protein activity.MethodsCM patients (N = 248) and controls (N = 274) were enrolled in this study. Genotyping was performed by real-time polymerase chain reaction (PCR), and JAK1, JAK2, and STAT3 expression was assessed by quantitative PCR (qPCR). STAT3 c.-1937C>G SNV was investigated by luciferase, qPCR, western blot, apoptosis, and cell cycle assays in SKMEL-28 cells with CC or GG genotype.ResultsIndividuals with STAT3 c.*1671TT and c.-1937CC genotypes and TC haplotype of both SNVs were under about 2.0-fold increased risk of CM. Specific JAK1, JAK2, and STAT3 combined genotypes were associated with up to 4.0-fold increased risk of CM. Higher luciferase activity [4,013.34 vs. 2,463.32 arbitrary units (AU); p = 0.004], STAT3 expression by qPCR (649.20 vs. 0.03 AU; p = 0.003) and western blot (1.69 vs. 1.16 AU; p = 0.01), and percentage of cells in the S phase of the cell cycle (57.54 vs. 30.73%; p = 0.04) were more frequent in SKMEL-28 with STAT3 c.-1937CC than with GG genotype. CM cell line with CC genotype presented higher STAT3 protein levels than the one with GG genotype (1.93 versus 1.27 AU, p = 0.0027).ConclusionOur data present preliminary evidence that inherited abnormalities in the JAK/STAT pathway can be used to identify individuals at a high risk of CM, who deserve additional attention for tumor prevention and early detection.

Sandfly fever viruses are emerging Phleboviruses typically causing mild febrile illness. Some strains, however, can cause severe and occasionally fatal neuro-invasive disease. Like most viruses, Phleboviruses have devised various strategies to inhibit the type I interferon (IFN) response to support a productive infection. Still, most of the strategies identified so far focus on inhibiting the sensing arm of the IFN response. In contrast, the effect of sandfly virus infection on signaling from the IFN receptor is less characterized. Therefore, we tested the effect of sandfly fever virus Naples (SFNV) and Sicily (SFSV) infection on IFN signaling. We found that infection with either of these viruses inhibits signaling from the IFN receptor by inhibiting STAT1 phosphorylation and nuclear localization. We show that the viral nonstructural protein NSs mediates these effects, but only NSs from SFNV was found to interact with STAT1 directly. Thus, we tested the upstream IFN signaling components and found that Janus kinase 1 (Jak1) phosphorylation is also impaired by infection.Furthermore, the NSs proteins from both viruses directly interacted with Jak1. Last, we show that IFN inhibition by SFNV and SFSV is most likely downstream of the IFN receptor at the Jak1 level. Overall, our results reveal the multiple strategies used by these related viruses to overcome host defenses.

Systemic lupus erythematosus is a chronic inflammatory disease, in which treatment is still limited due to suboptimal efficacy and toxicities associated with the available therapies. JAK kinases are well known to play an important role in systemic lupus erythematous. There is growing evidence that ROCK kinases are also important in disease development. In this paper, we present the results of the development of CPL409116, a dual JAK and ROCK inhibitor. The studies we performed demonstrate that this molecule is an effective JAK and ROCK inhibitor which efficiently blocks disease progression in NZBWF1/J mouse models of systemic lupus erythematous.

Janus kinase (JAK)/signal transducer and activator of transcription signaling (STAT) has been implicated in the pathophysiology of hidradenitis suppurativa (HS). This study evaluated treatment-related transcriptomic and proteomic changes in patients with moderate-to-severe HS treated with the investigational oral JAK1-selective inhibitor povorcitinib (INCB054707) in two phase 2 trials. Lesional skin punch biopsies (baseline and Week 8) were taken from active HS lesions of patients receiving povorcitinib (15 or 30 mg) once daily (QD) or a placebo. RNA-seq and gene set enrichment analyses were used to evaluate the effects of povorcitinib on differential gene expression among previously reported gene signatures from HS and wounded skin. The number of differentially expressed genes was the greatest in the 30 mg povorcitinib QD dose group, consistent with the published efficacy results. Notably, the genes impacted reflected JAK/STAT signaling transcripts downstream of TNF-α signaling, or those regulated by TGF-β. Proteomic analyses were conducted on blood samples obtained at baseline and Weeks 4 and 8 from patients receiving povorcitinib (15, 30, 60, or 90 mg) QD or placebo. Povorcitinib was associated with transcriptomic downregulation of multiple HS and inflammatory signaling markers as well as the reversal of gene expression previously associated with HS lesional and wounded skin. Povorcitinib also demonstrated dose-dependent modulation of several proteins implicated in HS pathophysiology, with changes observed by Week 4. The reversal of HS lesional gene signatures and rapid, dose-dependent protein regulation highlight the potential of JAK1 inhibition to modulate underlying disease pathology in HS.

Overactive Janus kinases (JAKs) are known to drive leukemia, making them well-suited targets for treatment. We sought to identify new JAK-activating mutations and instead found a JAK1-inactivating pseudokinase mutation, V666G. In contrast to other pseudokinase mutations that canonically lead to an active kinase, the JAK1 V666G mutation led to under-activation seen by reduced phosphorylation. To understand the functional role of JAK1 V666G in modifying kinase activity we investigated its influence on other JAK kinases and within the Interleukin-2 pathway. JAK1 V666G not only inhibited its own activity, but its presence could inhibit other JAK kinases. These findings provide new insights into the potential of JAK1 pseudokinase to modulate its own activity, as well as of other JAK kinases. Thus, the features of the JAK1 V666 region in modifying JAK kinases can be exploited to allosterically inhibit overactive JAKs.