Janus Kinase Signal Research Articles

Role of Janus Kinase Inhibitors in Therapy of Psoriasis.

Janus kinases inhibitors are molecules that target Janus kinases—signal transducers and activators of transcription (JAK/STAT). They inhibit this intracellular signal pathway, blocking the gene transcription of crucial proinflammatory cytokines that play a central role in the pathogenesis of many inflammatory and autoimmune diseases, including psoriasis. This process reduces psoriatic inflammation. The JAK inhibitors are divided into two generations. The first generation of JAK inhibitors blocks two or more different Janus kinases. The second generation is more specified and blocks only one type of Janus kinase and has less side effects than the first generation. Tofacitinib, ruxolitinib and baricitinib belong to first generation JAK inhibitors and decernotinib and filgotinib belong to second group. This narrative review summarizes the role of Janus kinase inhibitors in the therapy of psoriasis. Oral JAK inhibitors show promise for efficacy and safety in the treatment of psoriasis. Studies to date do not indicate that JAK inhibitors are superior to recent biologic drugs in terms of efficacy. However, JAK inhibitors, due to their lack of increased incidence of side effects compared to other biologic drugs, can be included in the psoriasis treatment algorithm because they are orally taken. Nevertheless, further studies are needed to evaluate long-term treatment effects with these drugs.

Novel drug for COVID-19: Virafin a therapeutic breakthrough

Background: Pegylated Interferon Alpha-2b is synthesized via the use of PEG (polyethylene glycol). It is formulated via attaching a 12kDa mono methoxy polyethylene glycol moiety to the recombinant human Interferon Alpha-2b protein. Pegylated Interferon Alpha-2b acts via binding to the (JAK/STAT) Janus kinase signal transducer and activator of the transcription interferon receptor. The Pegylated Interferon Alpha-2b /Virafin binds to the (IFNAR1/2) alpha interferon receptor 1 and 2. Pegylated Interferon Alpha-2b better known as Virafin has been approved by the Drugs Controller General of India. This therapeutic agent is currently under a multicentric phase 3 trial with very promising results being reported. A single subcutaneous dose of Virafin has been shown to decrease the need for oxygen therapy in patients. This reduction in the need for oxygen therapy is a vital factor needed to provide relief to the Indian medical system in light of the recent oxygen shortages faced due to India’s worst wave of COVID-19 cases since the onset of the global pandemic. Pegylated Interferon Alpha-2b/ Virafin confers enhanced viral clearance and bolsters the immune response to induce a quicker recovery in patients with mild to moderate symptoms.
 Conclusion: It is of paramount importance that further research on Virafin is undertaken as it can hinder the progression of COVID-19, reduce pressure on the inundated health systems, and save countless lives.

Developing a JAK Inhibitor for Targeted Local Delivery: Ruxolitinib Cream.

Named after the two-faced Roman god of doorways, Janus kinases (JAKs) represent a class of tyrosine kinases. The JAK signaling pathway is pivotal for the downstream signaling of inflammatory cytokines, including interleukins, interferons, and multiple growth factors. This article provides an overview of the JAK pathway and signaling, its significance in immune-mediated dermatologic diseases and the development of a targeted, localized option of a selective JAK inhibitor, ruxolitinib cream. In the early 1990s, various discovery and clinical development programs were initiated to explore pharmaceutical inhibition of the JAK-STAT pathway. Incyte Corporation launched a strategy to identify molecules suitable for both topical as well as oral delivery. Ruxolitinib was designed as a molecule with low nanomolar potency selective for JAK1 and 2 enzymes, but without significant inhibition of non-JAK kinases, as well as physicochemical properties for both topical and oral administration. An oil-in-water emulsified ruxolitinib cream formulation was developed for topical application and was studied in multiple immune-mediated dermatologic diseases including psoriasis, alopecia areata, atopic dermatitis and vitiligo. Ruxolitinib cream represents a novel, JAK1/2 selective therapy that can be delivered directly to the skin to treat a number of cytokine-driven, inflammatory dermatoses.

Cerdulatinib Pharmacodynamics and Relationships to Tumor Response Following Oral Dosing in Patients with Relapsed/Refractory B Cell Malignancies: Results from a Phase I Dose Escalation Study

Preclinical studies suggest that the spleen tyrosine kinase (SYK) and Janus kinase (JAK) family members can contribute to both tumor intrinsic and microenvironment-derived survival signals. A dual inhibitor of these kinases (cerdulatinib) was therefore developed, and a phase I dose-escalation study was completed to understand tolerability and efficacy, and their relationship to pharmacokinetics (PK) and pharmacodynamics (PD). Here, we report on PK/PD relationships and associations with tumor response in patients from the phase I dose-escalation portion of the clinical trial (NCT01994382).Repeat CT scans were obtained from 6 patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL), 12 patients with follicular lymphoma (FL), 12 patients with diffuse large B cell lymphoma, and 6 patients with mantle cell lymphoma. Meaningful clinical responses were observed in patients with CLL/SLL and FL, as previously reported (Hamlin et al, 2016); hence, the correlation between tumor response and PD markers was examined in these patient populations.Complete inhibition of SYK and JAK signaling pathways was achieved in whole blood of dosed patients at tolerated exposures. The level of target inhibition in blood correlated with serum cerdulatinib concentration, and the concentrations at which 50% inhibition was acheived (IC50) against B cell antigen receptor (BCR), interleukin (IL)-2, IL-4, and IL-6 signaling pathways ranged from 0.22-1.08 μM, depending on the phosphorylation event measured. Significant correlations were observed between inhibition of both SYK and JAK signaling pathways and tumor response, most notably the BCR and IL-4 signaling pathways. Serum markers of inflammation were also reduced following cerdulatinib administration, several of which significantly correlated with tumor response, including β-2 microglobulin, C-reactive protein, interferon γ-induced protein 10 (IP10), and macrophage inflammatory protein 3β (MIP3β). Of note, lymphocytosis was observed in CLL, SLL, and FL patients. Evidence of diminished tumor cell surface expression of CD69 and CD86, diminished CD5 expression (a negative regulator of BCR signaling), and enhanced C-X-C chemokine receptor type 4 (CXCR4) expression were observed in 2 patients with CLL, consistent with suppression of BCR and IL-4 signaling.Fresh tumor samples were obtained from the peripheral blood of 6 CLL patients treated with cerdulatinib, as well as archival tumor biopsies obtained from 4 FL patients and 1 MCL patient, which were submitted for next-generation sequencing. Clinical activity was observed in CLL patients bearing mutations to NOTCH1, ATM, p53, and KRAS, which are among the most frequently observed mutations in this disease. One of the responding patients bore a 17p deletion. Importantly, 2 patients with ibrutinib-relapsed CLL who progressed within the first cycle of therapy with cerdulatinib had 3 mutations in common: p53, EP300, and BTK (C481S). Genetic correlates in FL were more limited, with data on 4 patients, 3 of whom had evidence of tumor reduction and 1 which progressed. The 2 best responding patients with whom we have genetic information bore mutations to ZMYM3, KMT2D, FAT4, BCL2, BCL6, CD79B, and STAT6 . Lastly, strong clinical activity was observed in a transformed FL patient who presented with increased MYC, BCL2, and BCL6 expression by immunohistochemistry (“triple-hit” lymphoma).These data demonstrate the ability of cerdulatinib to potently and selectively inhibit SYK and JAK signaling at tolerated exposures in patients with relapsed/refractory B cell malignancies. Moreover, the extent of target inhibition, as well as suppression of inflammation, correlated with tumor response. Cerdulatinib is currently under investigation as part of a phase IIa study to further evaluate efficacy and tolerability in this population. DisclosuresCoffey:Portola Pharmaceuticals, Inc.: Employment, Equity Ownership. Feng:Portola Pharmaceuticals, Inc.: Employment, Equity Ownership. Betz:Portola Pharmaceuticals, Inc: Employment, Equity Ownership. Pandey:Portola Pharmaceuticals, Inc.: Employment, Equity Ownership. Birrell:Portola Pharmaceuticals, Inc.: Employment, Equity Ownership. Leeds:Portola Pharmaceuticals, Inc.: Employment, Equity Ownership. Der:Portola Pharmaceuticals, Inc.: Employment, Equity Ownership. Kadri:Portola Pharmacueticals, Inc.: Research Funding. Lu:Portola Pharmacueticals, Inc.: Research Funding. Segal:Portola Pharmacueticals, Inc.: Research Funding. Wang:Karyopharm: Research Funding; Portola: Research Funding. Michelson:Portola Pharmacueticals, Inc.: Employment. Curnutte:Portola Pharmaceuticals, Inc.: Employment, Equity Ownership. Conley:Portola Pharmaceuticals, Inc.: Employment, Equity Ownership, Patents & Royalties.

Ruxolitinib Inhibits Toll-like Receptor or GM-CSF, but Not TREM-1 Mediated Neutrophil Activation

Introduction: Ruxolitinib (RUX) is the first Janus kinase (JAK)1/2 inhibitor approved for the treatment of myelofibrosis (MF) or polycytemia vera (PV), as the pathogenesis of these myeloproliferative neoplasms is linked to a dysregulation of JAK signaling. In clinical trials, RUX demonstrates a profound reduction of splenomegaly and constitutive symptoms along with an improved quality of life. The most frequent adverse events of RUX include anemia and thrombocytopenia. However, beyond this, severe infectious complications have been reported in association with RUX treatment, such as C. neoformans pneumonia, toxoplasmosis retinitis and hepatitis B virus reactivation, indicating immunosuppressive effects of this drug. On the cellular level, RUX has yet been characterized as a negative regulator for NK- and T-cell functions, possibly accounting for the side effects observed. In our present work, we focused on the impact of RUX on polymorphonuclear neutrophil (PMN) activation as important regulators of the innate immune response.Methods: Purified PMN from healthy human donors were isolated by dextran sedimentation and HistopaqueÒ centrifugation and pretreated with RUX. PMN were activated with anti-TREM-1 agonistic antibody (6B1), isotope matched control antibody (4C9) (both own production), lipopolysaccharide (LPS), zymosan or GM-CSF and effector functions like phagocytosis by fluorochrome labeled polystyrene beads, L-selectin (CD62L) shedding, oxidative burst and IL-8 secretion were analyzed. In addition, blood samples of patients under RUX treatment and samples of age matched healthy volunteers were stimulated either with GM-CSF, LPS or zymosan. Afterwards functionality of PMN was analyzed by determination of oxidative burst, phagocytosis, L-selectin shedding and degranulation.Results: Ligation of TREM-1 (by specific antibody), TLR2/6 (by zymosan), TLR4 (by LPS) or GM-CSF-R induced a strong activation of PMN derived from healthy human donors, as shown by initiation of oxidative burst, increased phagocytic activity as well as CD62L shedding and release of IL-8. The additional presence of RUX revealed an impaired phagocytosis, CD62L shedding and IL-8 production after activation with the TLR agonists (LPS, zymosan) or GM-CSF, whereas no profound impact of pretreatment was observed on TREM-1 mediated effector functions. These results suggest that the inhibition of JAK signaling affects TLR and GM-CSF mediated PMN activation, while this particular pathway appears functionally irrelevant for TREM-1 mediated PMN activation. In line with these results, we observed impaired PMN functions in patients receiving RUX treatment compared to healthy controls with the most impressive impact on the oxidative burst and phagocytosis after LPS or zymosan stimulation.Conclusion: These data provide deeper insights on the impact of RUX as an immunosuppressant of innate immunity on the cellular level adding the selective inhibition of distinct PMN activating receptor pathways. The observation of impaired effector functions of PMN after RUX pretreatment in vitro as well as in vivo may help to explain the severe infectious complications accompanying MF or PV. DisclosuresKindler:Novartis: Membership on an entity's Board of Directors or advisory committees. Radsak:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support; Gilead: Other: Travel support; Acceleron: Research Funding.

Identifying the active compounds and mechanism of action of Banxia Xiexin decoction for treating ethanol-induced chronic gastritis using network pharmacology combined with UPLC–LTQ–Orbitrap MS

BackgroundBanxia Xiexin decoction (BXD), a traditionally prescribed Chinese medicine, has been used to treat chronic gastritis for many years. However, the underlying mechanism and targets for its effects remain unknown. In the present study, we predicted the targets and active compounds of BXD in the treatment of chronic gastritis through network pharmacology and ultra-performance liquid chromatography coupled with linear trap quadrupole–Orbitrap mass spectrometry (UPLC–LTQ–Orbitrap MS). MethodA chronic gastritis model was established in rats by oral administration of 56 % ethanol. BXD was orally administered for 7 days. Stomach tissues were collected for histopathological analysis, and tumour necrosis factor (TNF)-α, interleukin (IL)-2, IL-8, and lactate dehydrogenase (LDH) levels were measured by enzyme-linked immunosorbent assay. UPLC–LTQ–Orbitrap MS was established to analyse compounds in rat plasma following oral BXD administration. The absorbed ingredients were selected as candidate active compounds. The chronic gastritis-related targets were screened using multiple databases. The potential targets for the treatment of chronic gastritis were used to construct a protein–protein interaction (PPI) network and were also analysed using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Finally, molecular docking was used to uncover the interaction between multi-components and putative targets, and the results were verified by surface plasmon resonance (SPR). ResultsIntragastric administration of BXD ameliorated stomach injury resulting from chronic gastritis in rats and decreased the levels of TNF-α, IL-2, IL-8, and LDH. A comprehensive systematic strategy was used to successfully identify 38 candidate targets and 14 active compounds in BXD. Based on the network of compounds–targets and PPI, three hub genes that were associated with BXD therapy for chronic gastritis were selected and included intercellular adhesion molecule-1, peroxisome proliferator-activated receptor gamma and mitogen-activated protein kinase 14. The results of molecular docking and SPR demonstrated that the active compounds in BXD demonstrate affinity for these targets. Additionally, an enrichment analysis revealed that treatment of chronic gastritis with BXD primarily involves cytokine activation, the inflammatory response and nuclear factor-kappa B, hypoxia-inducible factor-1, phosphatidylinositol-3-kinase–protein–serine–threonine kinase and Janus kinase–signal transducer and activator of transcription signalling pathways, which may mediate the effects of BXD in the treatment of chronic gastritis. ConclusionBXD exhibits a therapeutic effect in ethanol-induced gastritis through multi-compound, multi-target and multi-pathway mechanisms. A strategy of network pharmacology combined with SPR may provide a feasible approach to explore the targets of herbal medicine and uncover novel bioactive components.

Dehydrocrenatidine extracted from Picrasmaquassioides induces the apoptosis of nasopharyngeal carcinoma cells through the JNK and ERK signaling pathways.

Nasopharyngeal carcinoma (NPC) is an indicator disease in Asia due to its unique geographical and ethnic distribution. Dehydrocrenatidine (DC) is a β-carboline alkaloid abundantly present in Picrasma quassioides (D. Don) Benn, a deciduous shrub or small tree native to temperate regions of southern Asia, and β-carboline alkaloids play anti-inflammatory and antiproliferative roles in various cancers. However, the mechanism and function of DC in human NPC cells remain only partially explored. The present study aimed to examine the cytotoxicity and biochemical role of DC in human NPC cells. The MTT method, cell cycle analysis, DAPI determination, Annexin V/PI double staining, and mitochondrial membrane potential examination were performed to evaluate the effects of DC treatment on human NPC cell lines. In addition, western blotting analysis was used to explore the effect of DC on apoptosis and signaling pathways in related proteins. The analysis results confirmed that DC significantly reduced the viability of NPC cell lines in a dose- and time-dependent manner and induced apoptosis through internal and external apoptotic pathways (including cell cycle arrest, altered mitochondrial membrane potential, and activated death receptors). Western blot analysis illustrated that DC's effect on related proteins in the mitogen-activated protein kinase pathway can induce apoptosis by enhancing ERK phosphorylation and inhibiting Janus kinase (JNK) phosphorylation. Notably, DC induced apoptosis by affecting the phosphorylation of JNK and ERK, and DC and inhibitors (SP600125 and U0126) in combination restored the overexpression of p-JNK and p-ERK. To date, this is the first study to confirm the apoptosis pathway induced by DC phosphorylation of p-JNK and p-REK in human NPC. On the basis of evidence obtained from this study, DC targeting the inhibition of NPC cell lines may be a promising future strategy for NPC treatment.

Janus kinase inhibitors ruxolitinib and baricitinib impair glycoprotein-VI mediated platelet function

Several Janus kinase (JAK) inhibitors (jakinibs) have recently been approved to treat inflammatory, autoimmune and hematological conditions. Despite emerging roles for JAKs and downstream signal transducer and activator of transcription (STAT) proteins in platelets, it remains unknown whether jakinibs affect platelet function. Here, we profile platelet biochemical and physiological responses in vitro in the presence of five different clinically relevant jakinibs, including ruxolitinib, upadacitinib, oclacitinib, baricitinib and tofacitinib. Flow cytometry, microscopy and other assays found that potent JAK1/2 inhibitors baricitinib and ruxolitinib reduced platelet adhesion to collagen, as well as platelet aggregation, secretion and integrin αIIbβ3 activation in response to the glycoprotein VI (GPVI) agonist collagen-related peptide (CRP-XL). Western blot analysis demonstrated that jakinibs reduced Akt phosphorylation and activation following GPVI activation, where ruxolitinib and baricitinib prevented DAPP1 phosphorylation. In contrast, jakinibs had no effects on platelet responses to thrombin. Inhibitors of GPVI and JAK signaling also abrogated platelet STAT5 phosphorylation following CRP-XL stimulation. Additional pharmacologic experiments supported roles for STAT5 in platelet secretion, integrin activation and cytoskeletal responses. Together, our results demonstrate that ruxolitinib and baricitinib have inhibitory effects on platelet function in vitro and support roles for JAK/STAT5 pathways in GPVI/ITAM mediated platelet function.

A Comprehensive Literature Review of JAK Inhibitors in Treatment of Alopecia Areata.

Alopecia areata (AA) is a chronic, immune-mediated form of nonscarring alopecia that is multifactorial and results in localized patches. It is often described as a self-limiting condition that results in the spontaneous regrowth of hair in most cases. However, this regrowth may take several months or years to occur in some patients, leading to the development of psychoemotional trauma in those that are affected. Although several therapies for AA have been developed and tested, there is no specific treatment that has been approved, leading to the availability of many off-label conventional treatment options, with very limited responses. More recently, with the advancement of pre-clinical and genetic studies, a greater understanding of the pathomechanisms involved in the development of AA has been uncovered. This has resulted in the introduction of targeted therapies that use small molecules to block specific pathways involved in AA pathophysiology. As such, the use of janus kinase (JAK) inhibitors for treatment of AA has emerged. JAK inhibitors block the T-cell mediated inflammatory response thought to be the driving factor behind AA pathogenesis, by inhibiting the janus kinase (JAK) signal transducer and activator of transcription (STAT) signaling pathway, leading to a reversal of hair loss in AA patients. Thus, in an effort to demonstrate the efficacy of JAK inhibitors in the treatment of AA, several studies have been published within recent years. However, the question remains, “Are JAK inhibitors effective and safe in the management of Alopecia Areata?”. This review aims to provide a comprehensive report on the role, efficacy, and outcomes of using JAK inhibitors in the treatment of AA. To competently answer the research question highlighted, the most recent, quality articles published over a 10–15-year period were sourced using PubMed, NCBI, Research gate, Medline, Cochrane Central Register of Controlled Trials, EMBASE and Google scholar. The literature search was primarily focused on randomized controlled trials (RCTs); however, in the absence of such, only the most recently published case reports, case series, clinical trials and open-label studies published to date were included.

Lymphocyte modulation by tofacitinib in patients with rheumatoid arthritis.

Tofacitinib is an oral small molecule targeting the intracellular Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathways approved for the treatment of active rheumatoid arthritis (RA). We investigated the effects of tofacitinib on the response of RA lymphocytes to B and T cell collagen epitopes in their native and post-translationally modified forms. In particular, peripheral blood mononuclear cells (PBMCs) from patients with RA and healthy subjects were cultured with type II collagen peptides (T261-273, B359-369, carT261-273, citB359-369) or with phorbol myristate acetate (PMA)/ionomycin/CD40L in the presence or absence of 100nM tofacitinib for 20h and analyzed by fluorescence activated cell sorter (FACS). Cultures without brefeldin A were used for cytokine supernatant enzyme-linked immunosorbent assay (ELISA) analysis. Tofacitinib down-regulated inflammatory cytokines by stimulated B [interleukin (IL)-6 and tumor necrosis factor (TNF)-α] and T [interferon (IFN)-γ, IL-17 or TNF-α] cells in the short term, while a significant reduction of IL-17 and IL-6 levels in peripheral blood mononuclear cell (PBMC) supernatant was also observed. IL-10 was significantly reduced in collagen-stimulated B cells from patients with RA and increased in controls, thus mirroring an altered response to collagen self-epitopes in RA. Tofacitinib partially prevented the IL-10 down-modulation in RA B cells stimulated with collagen epitopes. In conclusion, the use of tofacitinib exerts a rapid regulatory effect on B cells from patients with RA following stimulation with collagen epitopes while not reducing inflammatory cytokine production by lymphocytes.

Targeting the JAK/STAT Pathway: A Combined Ligand- and Target-Based Approach

Janus kinases (JAKs) are a family of proinflammatory enzymes able to mediate the immune responses and the inflammatory cascade by modulating multiple cytokine expressions as well as various growth factors. In the present study, the inhibition of the JAK–signal transducer and activator of transcription (STAT) signaling pathway is explored as a potential strategy for treating autoimmune and inflammatory disorders. A computationally driven approach aimed at identifying novel JAK inhibitors based on molecular topology, docking, and molecular dynamics simulations was carried out. For the best candidates selected, the inhibitory activity against JAK2 was evaluated in vitro. Two hit compounds with a novel chemical scaffold, 4 (IC50 = 0.81 μM) and 7 (IC50 = 0.64 μM), showed promising results when compared with the reference drug Tofacitinib (IC50 = 0.031 μM).

Ruxolitinib ameliorates airway hyper responsiveness and lung inflammation in a corticosteroid-resistant murine model of severe asthma

Abstract Asthma prevalence has increased considerably over the decades and it is now considered as one of the most common chronic disorders in the world. While the current anti-asthmatic therapies are effective for most asthma patients, there are 10–30% subjects whose disease is not controlled by such agents and they account for about 50% of the healthcare costs of asthma. Such asthmatics develop severe asthma (SA), a condition characterized by a dominant Th1/Th17 cytokine response that is accompanied by type 2-low endotype. As JAK (Janus Kinase) signaling is very important for the activation of several cytokine pathways, we examined whether inhibition of JAKs might lessen the clinical and laboratory manifestations of SA. To that end, we employed a murine model that recapitulates the complex immune response identified in the airways of human SA patients. To induce SA, mice were sensitized with house dust mite extract (HDME) and c-di-GMP (mucosal adjuvant) and then subsequently challenged with HDME and a lower dose of c-di-GMP. In this model, treatment with the JAK inhibitor, ruxolitinib, significantly ameliorated all the features of SA, including airway hyper responsiveness and lung inflammation; cellular influx and cytokine production as well as total IgE antibody titers. Thus, these studies highlight the JAKs as critical targets for mitigating the hyper-inflammation that occurs in SA and provide the framework for their incorporation into future clinical trials for patients that have severe or difficult-to manage asthma.

Disease modifying agents of myeloproliferative neoplasms: a review.

The identification of driver mutations in Janus kinase (JAK) 2, calreticulin (CALR), and myeloproliferative leukemia (MPL) has contributed to a better understanding of disease pathogenesis by highlighting the importance of JAK signal transducer and activator of transcription (STAT) signaling in classical myeloproliferative neoplasms (MPNs). This has led to the therapeutic use of novel targeted treatments, such as JAK2 inhibitors. More recently, with the development of next-generation sequencing, additional somatic mutations, which are not restricted to MPNs, have been elucidated. Treatment decisions for MPN patients are influenced by the MPN subtype, symptom burden, and risk classification. Although prevention of vascular events is the main objective of therapy for essential thrombocythemia (ET) and polycythemia vera (PV) patients, disease-modifying drugs are needed to eradicate clonal hematopoiesis and prevent progression to more aggressive myeloid neoplasms. JAK inhibitors are a valuable therapeutic strategy for patients with myelofibrosis (MF) who have splenomegaly and/or disease-related symptoms, but intolerance, refractory, resistance, and disease progression still present challenges. Currently, allogeneic stem cell transplantation remains the only curative treatment for MF, but it is typically limited by age-related comorbidities and high treatment-related mortality. Therefore, a better understanding of the molecular pathogenesis and potential new therapies with the aim of modifying the natural history of the disease is important. In this article, I review the current understanding of the molecular basis of MPNs and clinical studies on potential disease-modifying agents.

The Impact of Age on Response to Infection in Drosophila.

This review outlines the known cellular pathways and mechanisms involved in Drosophila age-dependent immunity to pathogenic microorganisms such as bacteria and fungi. We discuss the implication of host signaling pathways such as the Toll, Immune Deficiency (IMD), Janus kinase signal transducer and activator of transcription (JAK/STAT), and Insulin/Insulin Growth Factor/Target of Rapamycin (IIS/TOR) on immune function with aging. Additionally, we review the effects that factors such as sexual dimorphism, environmental stress, and cellular physiology exert on age-dependent immunity in Drosophila. We discuss potential tradeoffs between heightened immune function and longevity in the absence of infection, and we provide detailed tables outlining the various assays and pathogens used in the cited studies, as well as the age, sex, and strains of Drosophila used. We also discuss the overlapping effects these pathways and mechanisms have on one another. We highlight the great utility of Drosophila as a model organism and the importance of a greater focus on age-dependent antiviral immunity for future studies.

Importance of WNT-dependent signaling for derivation and maintenance of primed pluripotent bovine embryonic stem cells†.

The WNT signaling system plays an important but paradoxical role in the regulation of pluripotency. In the cow, IWR-1, which inhibits canonical WNT activation and has WNT-independent actions, promotes the derivation of primed pluripotent embryonic stem cells from the blastocyst. Here, we describe a series of experiments to determine whether derivation of embryonic stem cells could be generated by replacing IWR-1 with other inhibitors of WNT signaling. Results confirm the importance of inhibition of canonical WNT signaling for the establishment of pluripotent embryonic stem cells in cattle and indicate that the actions of IWR-1 can be mimicked by the WNT secretion inhibitor IWP2 but not by the tankyrase inhibitor XAV939 or WNT inhibitory protein dickkopf 1. The role of Janus kinase-mediated signaling pathways for the maintenance of pluripotency of embryonic stem cells was also evaluated. Maintenance of pluripotency of embryonic stem cells lines was blocked by a broad inhibitor of Janus kinase, even though the cells did not express phosphorylated signal transducer and activator of transcription 3 (pSTAT3). Further studies with blastocysts indicated that IWR-1 blocks the activation of pSTAT3. A likely explanation is that IWR-1 blocks differentiation of embryonic stem cells into a pSTAT3+ lineage. In conclusion, results presented here indicate the importance of inhibition of WNT signaling for the derivation of pluripotent bovine embryonic stem cells, the role of Janus kinase signaling for maintenance of pluripotency, and the participation of IWR-1 in the inhibition of activation of STAT3.

Ruxolitinib, a JAK1/2 Inhibitor, Ameliorates Cytokine Storm in Experimental Models of Hyperinflammation Syndrome.

Hyperinflammatory syndromes comprise a heterogeneous group of disorders characterized by severe inflammation, multiple organ dysfunction, and potentially death. In response to antigenic stimulus (e.g., SARS-CoV-2 infection), overactivated CD8+ T-cells and macrophages produce high levels of proinflammatory cytokines, such as IFN-γ, TNF-α, IL-6, and IL-12. Multiple inflammatory mediators implicated in hyperinflammatory syndromes utilize the Janus kinase–signal transducers and activators of transcription (JAK-STAT) cascade to propagate their biological function. Our findings demonstrate that oral ruxolitinib dosing designed to mimic clinically relevant JAK-STAT pathway inhibition significantly reduces the harmful consequences of immune overactivation in multiple hyperinflammatory models. In contrast to monoclonal antibody therapies targeting a single cytokine, ruxolitinib effectively downregulates the functional effect of multiple cytokines implicated in hyperinflammatory states, without broad immunosuppression.

Anti-Inflammatory Treatment of COVID-19 Pneumonia With Tofacitinib Alone or in Combination With Dexamethasone is Safe and Possibly Superior to Dexamethasone as a Single Agent in a Predominantly African American Cohort.

ObjectiveTo explore the survival benefit of tofacitinib in addition to dexamethasone in hospitalized patients treated for coronavirus disease 2019 (COVID-19)–related pneumonia.Patients and MethodsThis is a single-center retrospective observational study. All patients who were hospitalized at Delta Regional Medical Center (a regional hospital in the Mississippi Delta) with a COVID-19 diagnosis and discharged between March 1 and September 30, 2020, are included. The primary outcome was in-hospital mortality in relation to receipt of tofacitinib alone or in addition to dexamethasone (designated as the tofacitinib group), versus dexamethasone alone (designated as the dexamethasone group).ResultsOf 269 eligible patients, 138 (51.3%) received tofacitinib uniformly and 131 (48.7%) patients received dexamethasone without tofacitinib. A total of 44 patients expired: 14 (31.8%) in the tofacitinib group and 30 (68.2%) in the dexamethasone group. The proportions of death among the tofacitinib and dexamethasone groups were, respectively, 10.1% and 22.9%. This represents a 70% reduction in odds of dying among the tofacitinib group compared to the dexamethasone group after adjusting for age and clinical parameters captured at hospitalization (adjusted odds ratio: 0.30; 95% CI: 0.12 to 0.76; P=.01).ConclusionThe in-patient treatment of COVID-19 pneumonia has rapidly evolved. The addition of dexamethasone has made a relevant improvement on survival. Other immunomodulators have yet to show an impact. Here we present the potential survival benefit of the Janus kinase–signal transducer and activator of transcription inhibitor tofacitinib on COVID-19 pneumonia. We found that adding tofacitinib-based anti-inflammatory therapy to a treatment regimen including dexamethasone in COVID-19 pneumonia seems to have potential benefit of improving survival when compared to dexamethasone alone.

Janus kinase signaling as risk factor and therapeutic target for severe SARS-CoV-2 infection.

Cytokine signaling, especially interferon (IFN) signaling is closely linked to several aspects of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection. During initial SARS‐CoV‐2 infection, symptomatic patients present with impaired type I/III IFN‐mediated antiviral responses. Interestingly, IFNs regulate the cellular entry receptor for SARS‐CoV‐2 on epithelial and endothelial cells. As reported recently, critically ill COVID‐19 patients show genetic polymorphisms in one IFN receptor gene (IFNRA2) and in a gene locus near the Janus kinase (JAK) TYK2, which is key for IFN, interleukin (IL)‐12 and IL‐23 signaling, and T helper (Th) 1/Th17 cell‐mediated antiviral immune responses. In the advanced stage of the disease, critically ill COVID‐19 patients develop a cytokine storm where many inflammatory mediators using the JAK/STAT signaling pathway such as IL‐6, IFN‐γ, the granulocyte colony‐stimulating factor (G‐CSF) or IL‐2, and chemokines result in an influx of macrophages and neutrophils damaging the lung tissue. The knowledge on the cytokine and JAK/STAT signaling pathways in severe COVID‐19 disease explains the promising first results with JAK inhibitors like baricitinib, which not only dampen the inflammation but in the case of baricitinib also affect virus replication and endocytosis in target cells. Here, we summarize the current immunological associations of SARS‐CoV‐2 infection with cytokine signaling, the JAK/STAT pathway, and the current clinical stage of JAK inhibitors for improving severe COVID‐19 disease.

Janus kinase inhibitors for atopic dermatitis: a promising treatment modality.

Atopic dermatitis (AD) is chronic, pruritic, inflammatory skin disease that affects a significant portion of the population in industrialized nations. For nonresponders to conventional therapies, AD can significantly reduce sleep quality and quality of life. AD pathogenesis is multifactorial and involves multiple immune pathways, with recent evidence of T helper (Th)2, Th17 and Th22 axis attenuation in various AD endotypes and racial subtypes. Inhibition of the conserved Janus kinase (JAK) signalling pathway represents a promising therapeutic avenue to reduce the activation of multiple proinflammatory mediators involved in AD pathogenesis. JAK inhibitors exist in both oral and topical forms with variable specificity for the receptor tyrosine kinases JAK1, JAK2, JAK3 and tyrosine kinase 2. Oral formulations include abrocitinib, upadacitinib, baricitinib and gusacitinib, and are most appropriate for patients with moderate to severe AD. Emerging topical formulation in development include ruxolitinib and deglocitinib, which may be used in patients with localized AD and also adjunctively with systemic therapy in patients with more severe disease. With observed rapidity in itch relief and accompanying dramatic reduction in inflammatory lesion count, JAK inhibitors represent a promising new treatment to revolutionize the management of AD.

Glycosides of Caulis Lonicerae inhibits the inflammatory proliferation of IL-1β-mediated fibroblast-like synovial cells cocultured with lymphocytes.

Caulis Lonicerae, the dried stem of Lonicera japonica, has been confirmed to have antiinflammatory and antioxidant therapeutic effects. In the present study, we aimed to evaluate the functional mechanism of glycosides extracted from Caulis Lonicerae on the inflammatory proliferation of interleukin-1 beta (IL-1β)-mediated fibroblast-like synoviocytes (FLSs) from rats. Rat FLSs (RSC-364) co-cultured with lymphocytes induced by IL-1β were used as a cell model. Glycosides in a freeze-dried powder of aqueous extract from Caulis Lonicerae were identified using high-performance liquid chromatography-electrospray ionization/mass spectrometry. After treatment with glycosides, the inflammatory proliferation of FLS, induced by IL-1β, decreased significantly. Flow cytometry analysis showed that treatment with glycosides restored the abnormal balance of T cells by intervening in the proliferation and differentiation of helper T (Th) cells. Glycosides also inhibited the activation of Janus kinase signal transducer and activator of transcription (JAK-STAT) and nuclear factor (NF)-κB signaling pathways by suppressing the protein expression of key molecules in these pathways. Therefore, we concluded that the glycosides of Caulis Lonicerae can intervene in the differentiation of Th cells, suppressing the activation of JAK-STAT and NF-κB signaling pathways, contributing to the inhibitory effect on inflammatory proliferation of FLS co-cultured with lymphocytes induced by pro-inflammatory cytokines.