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Cell Reports Mar 2023Janus kinases (JAKs) mediate signal transduction downstream of cytokine receptors. Cytokine-dependent dimerization is conveyed across the cell membrane to drive JAK...
Janus kinases (JAKs) mediate signal transduction downstream of cytokine receptors. Cytokine-dependent dimerization is conveyed across the cell membrane to drive JAK dimerization, trans-phosphorylation, and activation. Activated JAKs in turn phosphorylate receptor intracellular domains (ICDs), resulting in the recruitment, phosphorylation, and activation of signal transducer and activator of transcription (STAT)-family transcription factors. The structural arrangement of a JAK1 dimer complex with IFNλR1 ICD was recently elucidated while bound by stabilizing nanobodies. While this revealed insights into the dimerization-dependent activation of JAKs and the role of oncogenic mutations in this process, the tyrosine kinase (TK) domains were separated by a distance not compatible with the trans-phosphorylation events between the TK domains. Here, we report the cryoelectron microscopy structure of a mouse JAK1 complex in a putative trans-activation state and expand these insights to other physiologically relevant JAK complexes, providing mechanistic insight into the crucial trans-activation step of JAK signaling and allosteric mechanisms of JAK inhibition.
Topics: Animals; Mice; Janus Kinases; DNA-Binding Proteins; Cryoelectron Microscopy; Trans-Activators; Janus Kinase 1; Signal Transduction; Phosphorylation; Janus Kinase 2; Janus Kinase 3
PubMed: 36867534
DOI: 10.1016/j.celrep.2023.112201 -
Drugs Apr 2020Delgocitinib, a janus kinase (JAK) inhibitor, is being developed by Japan Tobacco for the treatment of autoimmune disorders and hypersensitivity, including inflammatory... (Review)
Review
Delgocitinib, a janus kinase (JAK) inhibitor, is being developed by Japan Tobacco for the treatment of autoimmune disorders and hypersensitivity, including inflammatory skin conditions. The JAK family of tyrosine kinases plays an important role in mediating the biological effects of several inflammatory cytokines, e.g. IL-4, IL-13 and IL-31, which are elevated in patients with atopic dermatitis. Delgocitinib inhibits all members of the JAK family [JAK1, JAK2, JAK3 and tyrosine kinase 2]. Topical delgocitinib (Corectim) is approved in Japan for the treatment of atopic dermatitis. This article summarizes the milestones in the development of delgocitinib leading to this first approval for the treatment of adults with atopic dermatitis. Clinical development of the topical formulation is also underway for alopecia areata, chronic hand eczema, discoid lupus erythematosus, inverse psoriasis and atopic dermatitis in several countries worldwide. Clinical development of an oral formulation of delgocitinib is also underway in Japan for the treatment of autoimmune disorders and hypersensitivity.
Topics: Animals; Autoimmune Diseases; Drug Approval; Humans; Hypersensitivity; Janus Kinase Inhibitors; Janus Kinases; Molecular Conformation; Pyrroles
PubMed: 32166597
DOI: 10.1007/s40265-020-01291-2 -
Rheumatology (Oxford, England) Feb 2024Janus kinases (JAKs) are a family of cytosolic tyrosine kinases that regulate cytokine signal transduction, including cytokines involved in a range of inflammatory... (Review)
Review
Janus kinases (JAKs) are a family of cytosolic tyrosine kinases that regulate cytokine signal transduction, including cytokines involved in a range of inflammatory diseases, such as RA, psoriasis, atopic dermatitis and IBD. Several small-molecule JAK inhibitors (JAKis) are now approved for the treatment of various immune-mediated inflammatory diseases. There are, however, key differences between these agents that could potentially translate into unique clinical profiles. Each JAKi has a unique chemical structure, resulting in a distinctive mode of binding within the catalytic cleft of the target JAK, and giving rise to distinct pharmacological characteristics. In addition, the available agents have differing selectivity for JAK isoforms, as well as off-target effects against non-JAKs. Other differences include effects on haematological parameters, DNA damage repair, reproductive toxicity and metabolism/elimination. Here we review the pharmacological profiles of the JAKis abrocitinib, baricitinib, filgotinib, peficitinib, tofacitinib and upadacitinib.
Topics: Humans; Janus Kinase Inhibitors; Antirheumatic Agents; Arthritis, Rheumatoid; Janus Kinases; Psoriasis
PubMed: 37624925
DOI: 10.1093/rheumatology/kead448 -
Immunological Medicine Sep 2023Janus kinase inhibitors (JAKis) are a group of drugs with a different mechanism of action from biologics and are most rapidly uptaken in the rheumatology field. JAK is a... (Review)
Review
Janus kinase inhibitors (JAKis) are a group of drugs with a different mechanism of action from biologics and are most rapidly uptaken in the rheumatology field. JAK is a protein kinase activated in the cytoplasm by multiple cytokines and hormones involved in inflammatory pathology. The expression of JAK has been observed in various diseases, indicating the utility of JAK inhibitors in a wide variety of immune-mediated inflammatory diseases. Clinical trials are underway for a number of different rheumatic diseases based on the therapeutic efficacy of JAKis, which is comparable to that of biologics. This article will review the current status of JAKis for rheumatic diseases in terms of efficacy and safety and extend to future clinical applications for rare diseases.
Topics: Humans; Janus Kinase Inhibitors; Rheumatology; Rheumatic Diseases; Janus Kinases; Biological Products
PubMed: 36744577
DOI: 10.1080/25785826.2023.2172808 -
Nature Cancer Sep 2022Emerging evidence indicates that various cancers can gain resistance to targeted therapies by acquiring lineage plasticity. Although various genomic and transcriptomic...
Emerging evidence indicates that various cancers can gain resistance to targeted therapies by acquiring lineage plasticity. Although various genomic and transcriptomic aberrations correlate with lineage plasticity, the molecular mechanisms enabling the acquisition of lineage plasticity have not been fully elucidated. We reveal that Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling is a crucial executor in promoting lineage plasticity-driven androgen receptor (AR)-targeted therapy resistance in prostate cancer. Importantly, ectopic JAK-STAT activation is specifically required for the resistance of stem-like subclones expressing multilineage transcriptional programs but not subclones exclusively expressing the neuroendocrine-like lineage program. Both genetic and pharmaceutical inhibition of JAK-STAT signaling resensitizes resistant tumors to AR-targeted therapy. Together, these results suggest that JAK-STAT are compelling therapeutic targets for overcoming lineage plasticity-driven AR-targeted therapy resistance.
Topics: Humans; Janus Kinases; Male; Pharmaceutical Preparations; Prostatic Neoplasms; Receptors, Androgen; STAT Transcription Factors
PubMed: 36065066
DOI: 10.1038/s43018-022-00431-9 -
Gastroenterology May 2020Inhibitors of Janus kinases (JAKs) are being developed for treatment of inflammatory bowel diseases and other immune-mediated diseases. Tofacitinib is effective in... (Meta-Analysis)
Meta-Analysis
BACKGROUND & AIMS
Inhibitors of Janus kinases (JAKs) are being developed for treatment of inflammatory bowel diseases and other immune-mediated diseases. Tofacitinib is effective in treatment of ulcerative colitis, but there are safety concerns. We performed a systematic review and meta-analysis to investigate the safety profile of tofacitinib, upadacitinib, filgotinib, and baricitinib in patients with rheumatoid arthritis, inflammatory bowel diseases, psoriasis, or ankylosing spondylitis.
METHODS
We searched the MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials from January 1, 1990, through July 1, 2019. We performed a manual review of conference databases from 2012 through 2018. The primary outcome was incidence rates of adverse events (AEs) and serious AEs. We also estimated incidence rates of serious infections, herpes zoster infection, non-melanoma skin cancer, other malignancies, major cardiovascular events, venous thromboembolism, and mortality. We performed a meta-analysis, which included controlled studies, to assess the relative risk of these events.
RESULTS
We identified 973 studies; of these, 82 were included in the final analysis, comprising 66,159 patients with immune-mediated diseases who were exposed to a JAK inhibitor. Two-thirds of the included studies were randomized controlled trials. The incidence rate of AEs was 42.65 per 100 person-years and of serious AEs was 9.88 per 100 person-years. Incidence rates of serious infections, herpes zoster infection, malignancy, and major cardiovascular events were 2.81 per 100 person-years, 2.67 per 100 person-years, 0.89 per 100 person-years, and 0.48 per 100 person-years, respectively. Mortality was not increased in patients treated with JAK inhibitors compared with patients given placebo or active comparator (relative risk 0.72; 95% confidence interval 0.40-1.28). The meta-analysis showed a significant increase in risk of herpes zoster infection among patients who received JAK inhibitors (relative risk 1.57; 95% confidence interval 1.04-2.37).
CONCLUSIONS
In a systematic review and meta-analysis, we found an increased risk of herpes zoster infection among patients with immune-mediated diseases treated with JAK inhibitors. All other AEs were not increased among patients treated with JAK inhibitors.
Topics: Arthritis, Rheumatoid; Azetidines; Herpes Zoster; Heterocyclic Compounds, 3-Ring; Humans; Incidence; Inflammatory Bowel Diseases; Janus Kinase Inhibitors; Janus Kinases; Piperidines; Placebos; Psoriasis; Purines; Pyrazoles; Pyridines; Pyrimidines; Pyrroles; Randomized Controlled Trials as Topic; Spondylitis, Ankylosing; Sulfonamides; Survival Analysis; Treatment Outcome; Triazoles
PubMed: 31926171
DOI: 10.1053/j.gastro.2020.01.001 -
The Journal of Allergy and Clinical... May 2021
Topics: Granuloma Annulare; Humans; Janus Kinases; STAT Transcription Factors
PubMed: 33713770
DOI: 10.1016/j.jaci.2021.03.003 -
Journal Der Deutschen Dermatologischen... Jan 2022Numerous chronic inflammatory skin diseases are associated with the release of proinflammatory cytokines, which act via the intracellular JAK-STAT pathway. JAK... (Review)
Review
Numerous chronic inflammatory skin diseases are associated with the release of proinflammatory cytokines, which act via the intracellular JAK-STAT pathway. JAK inhibitors represent a promising, targeted therapeutic approach for cutaneous diseases. Impressive effects have been achieved with these agents in recent years. With the approval of the JAK-inhibitors Baricitinib, Upadacitinib and Abrocitinib, new systemic therapeutic agents are now available for moderate to severe atopic dermatitis. Other diseases in which the effectiveness of these small molecules could be shown are psoriasis, chilblain lupus, dermatomyositis, vitiligo and alopecia areata. As dermatologists, we are facing a whole series of new drug approvals. In this minireview we explain the active principles of JAK inhibitors and review study results in selected inflammatory skin diseases. Finally, possible side effects and initial as well as follow-up laboratory examinations for these drugs are discussed.
Topics: Alopecia Areata; Dermatology; Humans; Janus Kinase Inhibitors; Janus Kinases; Vitiligo
PubMed: 34962052
DOI: 10.1111/ddg.14668 -
Frontiers in Immunology 2021Cellular therapies such as allogeneic hematopoietic stem cell transplantation (HSCT) and immune-effector cell therapy (IECT) continue to have a critical role in the... (Review)
Review
Cellular therapies such as allogeneic hematopoietic stem cell transplantation (HSCT) and immune-effector cell therapy (IECT) continue to have a critical role in the treatment of patients with high risk malignancies and hematologic conditions. These therapies are also associated with inflammatory conditions such as graft--host disease (GVHD) and cytokine release syndrome (CRS) which contribute significantly to the morbidity and mortality associated with these therapies. Recent advances in our understanding of the immunological mechanisms that underly GVHD and CRS highlight an important role for Janus kinases (JAK). JAK pathways are important for the signaling of several cytokines and are involved in the activation and proliferation of several immune cell subsets. In this review, we provide an overview of the preclinical and clinical evidence supporting the use of JAK inhibitors for acute and chronic GVHD and CRS.
Topics: Animals; Cytokine Release Syndrome; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Janus Kinase Inhibitors; Janus Kinases; Signal Transduction
PubMed: 34531878
DOI: 10.3389/fimmu.2021.740847 -
The Journal of Allergy and Clinical... Oct 2021Asthma is an inflammatory disease of the airways characterized by intermittent episodes of wheezing, chest tightness, and cough. Many of the inflammatory pathways... (Review)
Review
Asthma is an inflammatory disease of the airways characterized by intermittent episodes of wheezing, chest tightness, and cough. Many of the inflammatory pathways implicated in asthma involve cytokines and growth factors that activate Janus kinases (JAKs). The discovery of the JAK/signal transducer and activator of transcription (STAT) signaling pathway was a major breakthrough that revolutionized our understanding of cell growth and differentiation. JAK inhibitors are under active investigation for immune and inflammatory diseases, and they have demonstrated clinical efficacy in diseases such as rheumatoid arthritis and atopic dermatitis. Substantial preclinical data support the idea that inhibiting JAKs will ameliorate airway inflammation and hyperreactivity in asthma. Here, we review the rationale for use of JAK inhibitors in different asthma endotypes as well as the preclinical and early clinical evidence supporting such use. We review preclinical data from the use of systemic and inhaled JAK inhibitors in animal models of asthma and safety data based on the use of JAK inhibitors in other diseases. We conclude that JAK inhibitors have the potential to usher in a new era of anti-inflammatory treatment for asthma.
Topics: Animals; Asthma; Drug Administration Routes; Humans; Janus Kinase Inhibitors; Janus Kinases; STAT Transcription Factors
PubMed: 34625142
DOI: 10.1016/j.jaci.2021.08.013