Janus-activated Kinase Inhibitor Research Articles

Practical guidance for managing patients with moderate-to-severe ulcerative colitis using small molecule therapies.

Ulcerative colitis (UC) is a severe and debilitating illness that affects the quality of life and physical health of many Canadians. Given the dynamic and progressive nature of the disease, advanced therapies are required to support its long-term management. The emergence of small molecule therapies offers novel treatment options that target mechanisms central to the immunopathology of UC. Sphingosine-1-phosphate (S1P) receptor modulators and Janus-activated kinase inhibitors are 2 classes of therapies that target unique pathways to attenuate inflammation and modulate the immune response characteristic of UC. This review aims to provide practical guidance on how these therapeutic options can best be used to optimize treatment management and highlight the emerging role of small molecule therapies as a treatment strategy for UC.

Effectiveness of Janus kinase inhibitors in rheumatoid arthritis: systematic review and meta-analysis

Aim. To assess the efficacy profiles of different dosing regimens of tofacitinib, baricitinib, and upadacitinib — novel selective oral Janus activated kinase inhibitors, in rheumatoid arthritis (RA). Materials and methods. Randomized controlled trials of tofacitinib, baricitinib and upadacitinib in RA were identified from MEDLINE, and Cochrane databases. Random- effects models were used to estimate pooled mean differences (MD) and relative risks (RRs). American College of Rheumatology 20 % (ACR20), Health Assessment Questionnaire–Disability Index (HAQ-DI) were calculated. Results. Twenty trials with an overall low risk of bias were identified. Tofacitinib, baricitinib, and upadacitinib improved RA control as deter -mined by ACR20 (RR, 2.03; 95 % CI, 1.87 to 2.20) and HAQ-DI (MD, −0.31; 95% CI, −0.34 to −0.28) compared with placebo. Conclusion. Tofacitinib, baricitinib, and upadacitinib significantly improve RA control. To make further decisions, comparative clinical trials of the Janus kinase inhibitors in the real-world clinical practice are necessary.

Analysis and Comparison of Synthesis Route of Small Molecule Kinase Inhibitors Tofacitinib

Tofacitinib is one of the Janus activated kinase inhibitors, and the compound is characteristic of its high-throughput screening and lead optimization of its role as a JAK3 inhibitor in the cure of autoimmune diseases and organ transplant rejection. It can be used to the recovery of rheumatoid arthritis and psoriatic arthritis. In this article, we will introduce tofacitinibs background and meaning, and then its function as a molecule kinase inhibitor. It has advantage on the remedy of inflammatory diseases. The initial synthesis procedure of tofacitinib is comparatively complicated and the cost is unaffordable. Thus, three synthesis routes are discussed, and the upsides and downsides of methods from aspects of atomic economy, reaction yield, purity and safety are analyzed. Tofacitinibs mechanism and application are further introduced. Although the three synthesis routes of tofacitinib introduced in this paper still have many shortcomings, we put forward some improvement ideas for the future synthesis routes and put forward the possibility of its future application.

Quality of life and disease activity of patients with rheumatoid arthritis on tofacitinib and biologic disease-modifying antirheumatic drug therapies.

The aim of this study was to analyze the therapeutic results of rheumatoid arthritis (RA) therapy with different biologic disease-modifying antirheumatic drugs (bDMARDs) and the first Janus-activated kinase (JAK) inhibitor in real-life clinical settings. This is a prospective, observational, longitudinal study at the largest rheumatology clinic in Bulgaria conducted during the period 2012-2020. One hundred seventy-four patients were followed up for a period of one year. Patients naïve to biological therapy were consecutively assigned on the available at the time bDMARDs (infliximab, etanercept, adalimumab, rituximab, golimumab, cetrolizumab, tocilizumab) or tofacitinib. We evaluated the disease activity score (DAS28-CRP), Health assessment questionnaires (HAQ) and short form 36 (SF-36) were applied at the initiation of biological therapy, after 6, and 12months of follow-up. We analyze the changes in the two major subgroups of SF36-physical (MCS) and mental health (PCS). The age and gender distribution were similar between the groups on bDMARDs and tsDMARD. All observed indicators for disease control and QoL improve after the initiation of the biological or JAK inhibitor therapy. We also analyze the effect of therapies on DAS28-CRP, HAQ, SF-36 (PCS, MCS). Dispersion analysis for the effect of therapy measured through DAS28 between 1st and 3rd measurement shows a statically significant difference in between the average effect of therapies (p = 0.005). According to the average change in DAS28 between the first and third measurement the most effective is the golimumab (Median difference = 2.745), followed by rituximab (median = 2.305) and etanercept (median = 2.070). According to the average change in HAQ between first and third the most effective is tofacitinib (median 0.563), followed rituximab and infliximab (median 0.500 for both). Less effective in term of HAQ changes between the first and third measurement appears to be etanercept (median difference 0.250). All differences are statistically significant (p < 0.05). Regarding the changes in the QoL measured with SF-36 MCS and PCS there is no statistically significant differences in the average effect of different therapeutic agents. Tofacitinib is non-inferior in comparison to bDMARDs and improve both-disease activity and QoL in patients with RA.

The interleukin-6 trans-signaling promotes progesterone production in human granulosa-lutein cells†.

As a critical paracrine regulator of multiple reproductive functions, the cytokine interleukin-6 (IL-6) is expressed in human granulosa cells and can be detected in follicular fluid. At present, the functional role of IL-6 in the regulation of ovarian steroidogenesis is controversial. Moreover, the detailed molecular mechanisms by which IL-6 regulates the production of progesterone in human granulosa cells remain to be elucidated. In the present study, we used primary and immortalized human granulosa-lutein (hGL) cells to investigate the effects of IL-6 on progesterone synthesis and the underlying molecular mechanisms. We found that IL-6 trans-signaling by the combined addition of IL-6 and soluble IL-6 receptor (sIL-6Rα)-induced steroidogenic acute regulatory expression and progesterone production in hGL cells. Additionally, IL-6/sIL-6Rα activated the phosphorylation of Janus activated kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3), and the cellular effects were abolished by AG490 (JAK2 inhibitor), C188-9 (STAT3 inhibitor), or siRNA-mediated knockdown of STAT3. IL-6 trans-signaling-induced activation of JAK2/STAT3 also upregulated the expression of suppressor of cytokine signaling 3, which, in turn, negatively regulated the JAK2/STAT3 pathway by suppressing STAT3 activation and its downstream effects. Our findings provide insight into the molecular mechanisms by which IL-6 trans-signaling modulates steroidogenesis in hGL cells.

Treatment of Juvenile Spondyloarthritis: Where We Stand

Juvenile spondyloarthritis is a subset of juvenile idiopathic arthritis (JIA) with onset in late childhood and adolescence and a strong association with human leukocyte antigen (HLA) B-27 positivity and familial aggregation that has the potential for axial involvement, potentially leading to ankylosing spondylitis. Current therapy for severe disease relies heavily on tumor necrosis factor inhibitors (TNFi). Treatment paradigms in children largely consist of extrapolation from studies on adults with spondyloarthritis. Additional therapies studied in adults include non-steroidal anti-inflammatory drugs (NSAIDs), blockade of the interleukin-17 (IL-17) and IL-23 axes, blockade of T-cell stimulation, phosphodiesterase (PDE)-4 inhibition, and Janus-activated kinase (JAK) pathway alteration. IL-17 blockade and IL-23 blockade are guideline approved after TNFi failure (and even as an alternative to TNFi) in adults, depending on concomitant inflammatory bowel and skin disease, with JAK and PDE-4 inhibition options following biologic failure. Neither pediatric nor adult guidelines address IL-6 blockade, T-cell co-stimulation blockade, or combination biologic therapy.

Efficacy and Safety of Tofacitinib, Baricitinib, and Upadacitinib for Rheumatoid Arthritis: A Systematic Review and Meta-Analysis

Objective: To assess the efficacy and safety profiles of different dosing regimens of tofacitinib, baricitinib, and upadacitinib, novel selective oral Janus activated kinase inhibitors, in rheumatoid arthritis (RA). MethodsRandomized controlled trials of tofacitinib (5 and 10 mg twice daily) baricitinib (2 and 4 mg daily), and upadacitinib (15 and 30 mg daily) in RA were identified from MEDLINE, EMBASE, and Cochrane databases through December 11, 2019. Random-effects models were used to estimate pooled mean differences and relative risks (RRs). American College of Rheumatology 20%, Health Assessment Questionnaire–Disability Index, adverse events, risk for infection, venous thromboembolic events, and malignancy were calculated. ResultsTwenty trials with an overall low risk of bias involving 8982 patients were identified. Tofacitinib, baricitinib, and upadacitinib improved RA control as determined by American College of Rheumatology 20% (RR, 2.03; 95% CI, 1.87 to 2.20) and Health Assessment Questionnaire–Disability Index scores (mean differences, −0.31; 95% CI, −0.34 to −0.28) compared with placebo. Adverse events were more frequent with upadacitinib, 30 mg, daily (RR, 1.15; 95% CI, 1.02 to 1.30); upadacitinib, 15 mg, daily (RR, 1.14; 95% CI, 1.02 to 1.27); and baricitinib, 4 mg, daily (RR, 1.13; 95% CI, 1.02 to 1.24). The risk for infection was highest with tofacitinib, 10 mg, twice daily (RR, 2.75; 95% CI, 1.72 to 4.41), followed by upadacitinib, 15 mg, daily (RR, 1.35; 95% CI, 1.14 to 1.60) and baricitinib, 4 mg, daily (RR, 1.28; 95% CI, 1.12 to 1.45). Data for venous thromboembolic events were not available for tofacitinib or baricitinib, but there was no increase in risk with upadacitinib (15 mg daily: RR, 2.34; 95% CI, 0.34 to 15.92). ConclusionTofacitinib, baricitinib, and upadacitinib significantly improve RA control. Head-to-head Janus activated kinase inhibitor clinical trials are needed to further inform decision making.

Oncostatin-M-Reactive Pericytes Aggravate Blood–Brain Barrier Dysfunction by Activating JAK/STAT3 Signaling In Vitro

Oncostatin M (OSM) is a cytokine of the interleukin (IL)-6 family members. It induces blood–brain barrier (BBB) dysfunction by activating Janus-activated kinase (JAK) and signal transducer and activator of transcription (STAT) 3 pathways in brain endothelial cells. Brain pericytes located around microvessels are one of the BBB constituents. Pericytes work as a boundary surface between the blood circulation and brain parenchyma, and their functions are altered under pathophysiological conditions, leading to BBB dysregulation. However, it remains unknown whether pericytes are associated with OSM-induced BBB dysfunction. We demonstrated that pericyte exposure to OSM (100 ng/mL) elevated phosphorylation of STAT3, a main OSM signaling pathway, and that pericytes expressed OSM receptors (OSMRs) including OSMRβ and glycoprotein 130. These results suggest that pericytes are able to respond to OSM. To determine the effects of OSM-reactive pericytes on BBB functions, rat brain endothelial cell (RBEC) monolayers were cultured with OSM-treated pericytes. The presence of pericytes exposed to 100 ng/mL of OSM for 48 h aggravated both the elevated permeability to sodium fluorescein and the lowered transendothelial electrical resistance which were induced by OSM in RBECs. This OSM-reactive pericyte-induced aggravation of lowered RBEC barrier function was reversed by ruxolitinib, a JAK inhibitor. These findings suggest that activated JAK/STAT3 signaling in pericytes contributes to OSM-produced BBB breakdown. Thus, OSM-reactive pericytes may have to be considered a characteristic machinery in the formation and progression of BBB breakdown under pathological conditions associated with increased OSM levels.

Novel Inhaled Pan-JAK Inhibitor, LAS194046, Reduces Allergen-Induced Airway Inflammation, Late Asthmatic Response, and pSTAT Activation in Brown Norway Rats.

The Janus-activated kinase (JAK) family together with signal transducer and activator of transcription (STAT) signaling pathway has a key role in regulating the expression and function of many inflammatory cytokines. This has led to the discovery of JAK inhibitors for the treatment of inflammatory diseases, some of them already in the market. Considering the adverse effects associated with JAK inhibition by oral route, we wanted to explore whether JAK inhibition by inhaled route is enough to inhibit airway inflammation. The aim of this study was to characterize the enzymatic and cellular potency and the selectivity of LAS194046, a novel JAK inhibitor, compared with the reference compounds ruxolitinib and tofacitinib. The efficacy of this new JAK inhibitor is described in a model of ovalbumin (OVA)-induced airway inflammation in Brown Norway rats by inhaled administration. As potential markers of target engagement, we assessed the effect of LAS194046 on the STAT activation state. LAS194046 is a selective inhaled pan-JAK inhibitor that reduces allergen-induced airway inflammation, late asthmatic response, and phosphor-STAT activation in the rat OVA model. Our results show that topical inhibition of JAK in the lung, without relevant systemic exposure, is sufficient to reduce lung inflammation and improve lung function in a rat asthma model. In summary, JAK-STAT pathway inhibition by inhaled route constitutes a promising therapeutic option for lung inflammatory diseases.

Effect of the JAK2/STAT3 signaling pathway on nerve cell apoptosis in rats with white matter injury.

The Janus activated kinase 2 (JAK2)/signal transducer and the activator of transcription 3 (STAT3) pathway are involved in many physiological processes, such as cell survival, inflammation, development, proliferation and differentiation. Increasing evidence has shown that this pathway also has neuron-specific functions in the central nervous system. In this study, the functional significance of the JAK2/STAT3 signaling pathway in nerve cell apoptosis in rats with white matter injury was evaluated. The rat model of white matter injury was established by ligating bilateral common carotid arteries, and the changes of the JAK2 and STAT3 phosphorylation in hippocampal neurons were evaluated using the immunohistochemistry. In addition, the effects of JAK2 inhibitor AG490 and STAT3 small interfering ribonucleic acids (siRNAs) on the expression of phosphorylated-JAK2 (pJAK2), STAT3 messenger RNAs (mRNAs) and pSTAT3 in hippocampal neurons of white matter injury rats were studied. The effects of both on cerebral infarction volume and neuron apoptosis in white matter injury rats were also investigated. The expression of pJAK2 and pSTAT3 were significantly increased after white matter injury in rats (p<0.05). JAK2 inhibitor AG490 markedly decreased the phosphorylation of JAK2 and STAT3 in hippocampal neurons in the model group (p<0.05). STAT3 siRNAs remarkably reduced the expression levels of STAT3 mRNA and protein in hippocampus neurons in the model group (p<0.05), while having no effect on the expression level of pJAK2 protein. AG490 and STAT3 siRNAs notably attenuated the volume of cerebral infarction in the model group, as well as reduced neuron apoptosis after white matter injury. The inhibition of the JAK2/STAT3 signaling pathway contributed to reducing the volume of cerebral infarction and neuron apoptosis in rats with white matter injury.

Oncostatin M-induced blood-brain barrier impairment is due to prolonged activation of STAT3 signaling in vitro.

Oncostatin M (OSM) is a member of the interleukin (IL)-6 family cytokines. We previously demonstrated that OSM induces blood-brain barrier (BBB) impairment. However, functional characterization of IL-6 family cytokines in BBB regulation and the cytokine-related intracellular signaling pathway remain unclear. In this study, we demonstrate that among IL-6 family cytokines, including IL-6 and leukemia inhibitory factor (LIF), OSM is the most potent molecule for inducing BBB dysfunction via prolonged activation of signal transducer and activator of transcription (STAT) 3 following Janus-activated kinase (JAK) activation. OSM but not IL-6 and LIF (100 ng/mL for 24 hours) markedly produced increased sodium fluorescein permeability and decreased transendothelial electrical resistance in rat brain endothelial cell (RBEC) monolayers. This OSM-induced BBB dysfunction was accompanied by decreased levels of claudin-5 expression in RBECs, which were ameliorated by JAK inhibitor. We examined the time-course of STAT3 phosphorylation in RBECs treated with OSM, IL-6, and LIF. OSM upregulated STAT3 phosphorylation levels during a 24 hours period with a peak at 10 minutes. While IL-6 and LIF transiently increased phosphorylated STAT3 at 10 minutes after addition, this phosphorylation decreased during the period from 1 to 24 hours after addition. These findings suggest that OSM-induced sustained increases in STAT3 phosphorylation levels largely contribute to BBB impairment. Thus, elevated OSM levels and activation of brain endothelial JAK/STAT3 signaling pathway under pathological conditions should be considered as a possible hallmark for induction and development of BBB impairment.

SiRNA Library Screening Identifies a Druggable Immune-Signature Driving Esophageal Adenocarcinoma Cell Growth.

Background & AimsEffective therapeutic approaches are urgently required to tackle the alarmingly poor survival outcomes in esophageal adenocarcinoma (EAC) patients. EAC originates from within the intestinal-type metaplasia, Barrett’s esophagus, a condition arising on a background of gastroesophageal reflux disease and associated inflammation.MethodsThis study used a druggable genome small interfering RNA (siRNA) screening library of 6022 siRNAs in conjunction with bioinformatics platforms, genomic studies of EAC tissues, somatic variation data of EAC from The Cancer Genome Atlas data of EAC, and pathologic and functional studies to define novel EAC-associated, and targetable, immune factors.ResultsBy using a druggable genome library we defined genes that sustain EAC cell growth, which included an unexpected immunologic signature. Integrating Cancer Genome Atlas data with druggable siRNA targets showed a striking concordance and an EAC-specific gene amplification event associated with 7 druggable targets co-encoded at Chr6p21.1. Over-representation of immune pathway–associated genes supporting EAC cell growth included leukemia inhibitory factor, complement component 1, q subcomponent A chain (C1QA), and triggering receptor expressed on myeloid cells 2 (TREM2), which were validated further as targets sharing downstream signaling pathways through genomic and pathologic studies. Finally, targeting the triggering receptor expressed on myeloid cells 2-, C1q-, and leukemia inhibitory factor–activated signaling pathways (TYROBP–spleen tyrosine kinase and JAK-STAT3) with spleen tyrosine kinase and Janus-activated kinase inhibitor fostamatinib R788 triggered EAC cell death, growth arrest, and reduced tumor burden in NOD scid gamma mice.ConclusionsThese data highlight a subset of genes co-identified through siRNA targeting and genomic studies of expression and somatic variation, specifically highlighting the contribution that immune-related factors play in support of EAC development and suggesting their suitability as targets in the treatment of EAC.

European perspective on the management of rheumatoid arthritis: clinical utility of tofacitinib.

Xeljanz® (tofacitinib) is an oral small-molecule inhibitor that reversibly inhibits Janus-activated kinase (JAK)-dependent cytokine signaling, thus reducing inflammation. As a result of these mechanisms, effects on the immune system such as a moderate decrease in the total lymphocyte count, a dose-dependent decrease in natural killer (NK) cell count, and an increase in B-cell count have been observed. Therefore, tofacitinib provides an innovative approach to modulating the immune and inflammatory responses in patients with rheumatoid arthritis (RA), which is especially important in individuals who do not respond to tumor necrosis factor inhibitors or show a loss of response over time. The aim of this article was to review studies on the pharmacology, mode of action, pharmacokinetics, efficacy, and safety of tofacitinib in patients with RA. Tofacitinib has been shown to reduce symptoms of RA and improve the quality of life in the analyzed groups of patients. Moreover, it showed high efficacy and an acceptable safety profile in Phase III randomized clinical trials on RA and was the first JAK inhibitor approved by the US Food and Drug Administration (FDA) and European Medicines Agency (EMA) in the RA therapy, thus providing a useful alternative treatment strategy. Randomized controlled studies revealed a significant benefit over placebo in efficacy outcomes (American College of Rheumatology [ACR] 20 and ACR50 response rates); accordingly, clinically meaningful improvements in patient-related outcomes compared with placebo have been reported. The safety profile seems acceptable, although some severe adverse effects have been observed, including serious infections, opportunistic infections (including tuberculosis and herpes zoster), malignancies, and cardiovascular events, which require strict monitoring irrespective of the duration of tofacitinib administration. As an oral drug, tofacitinib offers an alternative to subcutaneous or intravenous biologic drugs and should be recognized as a more convenient way of drug administration.

Inflammatory Bowel Disease: Updates on Molecular Targets for Biologics.

Therapy for inflammatory bowel disease (IBD) has changed, with several new agents being evaluated. The era of anti-tumor necrosis factor (anti-TNF) antibody therapy saw remarkable progress in IBD therapy. Some patients, however, do not respond to anti-TNF treatment, or their response decreases over time. This phenomenon highlights the need to identify new molecular targets for therapy in IBD. The targets of new therapeutic molecules in IBD must aim to restore immune dysregulation by the inhibition of proinflammatory cytokines (TNF-α, interleukin [IL]-6, IL-13, IL-17, IL-18, and IL-21) and augmentation of the effect of anti-inflammatory cytokines (IL-10, IL-11, and transforming growth factor β) and to pursue new anti-inflammatory targets, such as regulatory T-cell therapy, Smad7 antisense, Janus-activated kinase inhibition, Toll-like receptor stimulation, leukocyte adhesion, and blockade of T-cell homing via integrins and mucosal addressin cellular adhesion molecule-1. In addition, potential molecular targets could restore mucosal barrier function and stimulate mucosal healing. Despite these potential targets, the value and clinical significance of most new molecules remain unclear, and clinical efficacy and safety must be better defined before their implementation in clinical practice. This article aims to review the promising and emerging molecular targets that could be clinically meaningful for novel therapeutic approaches.

Anti-Leukemic Activity of the TYK2 Selective Inhibitor Ndi-031301 in T-Cell Acute Lymphoblastic Leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy resulting from the transformation of T-cell progenitors. Although the prognosis of this disease has substantially improved due to the introduction of intensified chemotherapy, the clinical outcome of T-ALL patients with primary resistant or relapsed disease remains poor, indicating that further therapeutic improvement is urgently needed. We have previously demonstrated that activation of tyrosine kinase 2 (TYK2) contributes to aberrant survival of human T-ALL cells. TYK2 is a member of the Janus-activated kinase (JAK) tyrosine kinase family and our report was the first to implicate TYK2 in T-ALL pathogenesis. Indeed, our gene knockdown experiments showed TYK2 dependency in 14 of 16 (88%) T-ALL cell lines and 5 of 8 (63%) patient-derived T-ALL cells tested, suggesting that inhibition of TYK2 would be beneficial in most patients with T-ALL. Based on these findings, we investigated the therapeutic potential of a novel small-molecule TYK2 kinase inhibitor NDI-031301 in T-ALL. We found that NDI-031301 shows potent and selective inhibitory activity against TYK2 in a cellular context, because this compound strongly inhibited the growth of TYK2-transfomed Ba/F3 cells when compared to the JAK inhibitors tofacitinib and baricitinib, whereas Ba/F3 cells transformed by other tyrosine kinases showed decreased sensitivity to NDI-031301. NDI-031301 induced robust growth inhibition in each of 4 human T-ALL cell lines representing different molecular subtypes of the disease (DU.528, KOPT-K1, HPB-ALL and SKW-3), with IC50 values of 0.8186 - 2.380 μM after 72 hours of exposure. NDI-031301 treatment of human T-ALL cell lines resulted in induction of apoptosis that was not observed with tofacitinib and baricitinib. To elucidate the mechanism of apoptosis induced by NDI-031301 in T-ALL cells, we next investigated cellular signaling pathways that are associated with cell survival and specifically affected by TYK2 inhibition with NDI-031301. Western blotting analysis demonstrated that treatment with 3 μM of NDI-031301 resulted in reduction of STAT1 Tyr-701 phosphorylation and BCL2 levels in KOPT-K1 cells, consistent with our previous finding that TYK2 phosphorylates STAT1 and upregulates BCL2 expression in most T-ALL cells. Surprisingly, the treatment also uniquely led to activation of three mitogen-activated protein kinases (MAPKs), resulting in phosphorylation of ERK, SAPK/JNK and p38 MAPK coincident with PARP cleavage, which was not observed with tofacitinib and baricitinib. NDI-031301-mediated activation of SAPK/JNK and p38 MAPK pathways are likely mediated through inhibition of TYK2, because increased phosphorylation levels of SAPK/JNK and p38 MAPK were observed in the cells transfected with TYK2-targeting shRNAs, while the levels of ERK1/2 phosphorylation were not upregulated. Further investigation revealed that activation of p38 MAPK occurred within 1 hour of NDI-031301 treatment and was responsible for NDI-031301-induced T-ALL cell death, as pharmacologic inhibition of p38 MAPK by SB203580 partially rescued apoptosis induced by TYK2 inhibitor, while inhibition of ERK or SAPK/JNK showed no rescue effects. Finally, we found that daily oral administration of NDI-031301 at 100mg/kg BID to immunodeficient mice engrafted with KOPT-K1 T-ALL cells was well tolerated, and led to decreased tumor burden and a significant survival benefit. After 29 days of treatment, the mice receiving NDI-031301 had marked reductions in infiltration of leukemia cells into spleen and bone marrow by comparison with controls. Thus, our findings clearly support TYK2 inhibition with NDI-031301 or a related compound as a potential therapeutic strategy for patients with T-ALL, and also raise the possibility that enhancing p38 MAPK activation in T-ALL cells may be an approach to accentuate its anti-leukemic activity. DisclosuresMasse:Nimbus Therapeutics: Employment. Miao:Nimbus Therapeutics: Employment. Rocnik:Nimbus Therapeutics: Employment. Kapeller:Nimbus Therapeutics: Employment.

Rapamycin negatively impacts insulin signaling, glucose uptake and uncoupling protein-1 in brown adipocytes

New onset diabetes after transplantation (NODAT) is a metabolic disorder that affects 40% of patients on immunosuppressive agent (IA) treatment, such as rapamycin (also known as sirolimus). IAs negatively modulate insulin action in peripheral tissues including skeletal muscle, liver and white fat. However, the effects of IAs on insulin sensitivity and thermogenesis in brown adipose tissue (BAT) have not been investigated. We have analyzed the impact of rapamycin on insulin signaling, thermogenic gene-expression and mitochondrial respiration in BAT. Treatment of brown adipocytes with rapamycin for 16h significantly decreased insulin receptor substrate 1 (IRS1) protein expression and insulin-mediated protein kinase B (Akt) phosphorylation. Consequently, both insulin-induced glucose transporter 4 (GLUT4) translocation to the plasma membrane and glucose uptake were decreased. Early activation of the N-terminal Janus activated kinase (JNK) was also observed, thereby increasing IRS1 Ser 307 phosphorylation. These effects of rapamycin on insulin signaling in brown adipocytes were partly prevented by a JNK inhibitor. In vivo treatment of rats with rapamycin for three weeks abolished insulin-mediated Akt phosphorylation in BAT. Rapamycin also inhibited norepinephrine (NE)-induced lipolysis, the expression of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) and uncoupling protein (UCP)-1 in brown adipocytes. Importantly, basal mitochondrial respiration, proton leak and maximal respiratory capacity were significantly decreased in brown adipocytes treated with rapamycin. In conclusion, we demonstrate, for the first time the important role of brown adipocytes as target cells of rapamycin, suggesting that insulin resistance in BAT might play a major role in NODAT development.

A phase I, open-label, dose-escalation, multicenter study of the JAK2 inhibitor NS-018 in patients with myelofibrosis

NS-018 is a Janus-activated kinase 2 (JAK2)-selective inhibitor, targeting the JAK–signal transducer and activator of transcription (STAT) pathway that is deregulated in myelofibrosis. In this phase I, dose-escalation portion of a phase I/II study, patients with myelofibrosis received oral NS-018 in continuous 28-day cycles. The primary study objective was to evaluate safety, tolerability and clinically active dose of NS-018. Forty-eight patients were treated; 23 (48%) had previously received a JAK inhibitor (JAKi). The most common drug-related adverse events were thrombocytopenia (27%)/anemia (15%) for hematologic events, and dizziness (23%)/nausea (19%) for non-hematologic events. Once daily NS-018 at 300 mg was chosen as the phase II study dose based on improved tolerability compared with higher doses. A ⩾50% reduction in palpable spleen size was achieved in 56% of patients (47% of patients with prior JAKi treatment), and improvements were observed in myelofibrosis-associated symptoms. Bone marrow fibrosis grade (local assessment) improved from baseline in 11/30 evaluable patients (37%) after 3 cycles of NS-018. JAK2 allele burden was largely unchanged. Changes in cytokine/protein levels were noted after 4 weeks of treatment. NS-018 reached peak plasma concentration in 1–2 h and did not accumulate with multiple dosing. NS-018 will be assessed in patients with previous JAKi exposure in the phase II portion.

Remifentanil Preconditioning Reduces Postischemic Myocardial Infarction and Improves Left Ventricular Performance via Activation of the Janus Activated Kinase-2/Signal Transducers and Activators of Transcription-3 Signal Pathway and Subsequent Inhibition of Glycogen Synthase Kinase-3β in Rats.

Remifentanil preconditioning attenuates myocardial ischemia reperfusion injury, but the underlying mechanism is incompletely understood. The Janus activated kinase-2 (JAK2)/signal transducers and activators of transcription-3 (STAT3) and phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathways are critical in both ischemic and pharmacologic preconditioning cardioprotection, which involve the inactivation of glycogen synthase kinase-3β. We hypothesized that remifentanil preconditioning confers cardioprotection via the JAK2/STAT3 and/or PI3K/Akt activation-mediated glycogen synthase kinase-3β inhibition. Pharmacologic intervention. Research laboratory. Male Sprague-Dawley rats. In vivo and in vitro treatments. Male Sprague-Dawley rats (n = 6 per group) were sham operated or subjected to myocardial ischemia reperfusion injury. The JAK2 inhibitor AG490 (3 mg/kg), the PI3K inhibitor wortmannin (15 μg/kg), or the glycogen synthase kinase-3β inhibitor SB216763 (600 μg/kg) were given before inducing in vivo myocardial ischemia reperfusion injury achieved by occluding coronary artery for 30 minutes followed by 120 minutes of reperfusion in the absence or presence of remifentanil preconditioning (6 μg/kg/min). Also, isolated rat hearts were Langendorff perfused and subjected to 30 minutes of global ischemia and 120 minutes of reperfusion without or with remifentanil preconditioning (100 ng/mL) in the presence or absence of AG490 and/or SB216763. Isolated rat cardiomyocytes and H9C2 cells were subjected to hypoxia/reoxygenation alone or in combination with AG490 (100 μM), wortmannin (100 nM), or SB216763 (3 μM) without or with remifentanil preconditioning (2.5 μM). Remifentanil preconditioning reduced postischemic myocardial infarction and hemodynamic dysfunction induced by myocardial ischemia reperfusion injury concomitant with increased phosphorylation of STAT3 at tyr-705 (p-STAT3) and glycogen synthase kinase-3β but not Akt. AG490 but not wortmannin cancelled remifentanil preconditioning cardioprotection, and SB216763 restored it despite the presence of AG490. In Langendorff-perfused hearts, AG490-mediated cancellation of remifentanil preconditioning cardioprotection in attenuating postischemic myocardial infarction and creatinine kinase-MB release was reverted by concomitant administration of SB216763. Remifentanil preconditioning also attenuated posthypoxic cardiomyocyte injury and increased p-STAT3 and glycogen synthase kinase-3β in isolated primary cardiomyocytes and H9C2 cells. STAT3 gene knockdown with specific synthetic RNA cancelled remifentanil preconditioning cardioprotection, whereas glycogen synthase kinase-3β gene knockdown, which per se did not affect STAT3 under hypoxia/reoxygenation condition, preserved remifentanil preconditioning cardioprotection regardless of STAT3 abrogation. Remifentanil preconditioning confers cardioprotection primarily via activation of JAK2/STAT3 signaling that can function independent of PI3K/Akt activation. Glycogen synthase kinase-3β is a critical downstream effector of remifentanil preconditioning cardioprotection.

Interferon-gamma potentiates NMDA receptor signaling in spinal dorsal horn neurons via microglia-neuron interaction.

BackgroundGlia–neuron interactions play an important role in the development of neuropathic pain. Expression of the pro-inflammatory cytokne →cytokine Interferon-gamma (IFNγ) is upregulated in the dorsal horn after peripheral nerve injury, and intrathecal IFNγ administration induces mechanical allodynia in rats. A growing body of evidence suggests that IFNγ might be involved in the mechanisms of neuropathic pain, but its effects on the spinal dorsal horn are unclear. We performed blind whole-cell patch-clamp recording to investigate the effect of IFNγ on postsynaptic glutamate-induced currents in the substantia gelatinosa neurons of spinal cord slices from adult male rats.ResultsIFNγ perfusion significantly enhanced the amplitude of NMDA-induced inward currents in substantia gelatinosa neurons, but did not affect AMPA-induced currents. The facilitation of NMDA-induced current by IFNγ was inhibited by bath application of an IFNγ receptor-selective antagonist. Adding the Janus activated kinase inhibitor tofacitinib to the pipette solution did not affect the IFNγ-induced facilitation of NMDA-induced currents. However, the facilitatory effect of IFNγ on NMDA-induced currents was inhibited by perfusion of the microglial inhibitor minocycline. These results suggest that IFNγ binds the microglial IFNγ receptor and enhances NMDA receptor activity in substantia gelatinosa neurons. Next, to identify the effector of signal transmission from microglia to dorsal horn neurons, we added an inhibitor of G proteins, GDP-β-S, to the pipette solution. In a GDP-β-S–containing pipette solution, IFNγ-induced potentiation of the NMDA current was significantly suppressed after 30 min. In addition, IFNγ-induced potentiation of NMDA currents was blocked by application of a selective antagonist of CCR2, and its ligand CCL2 increased NMDA-induced currents.ConclusionOur findings suggest that IFNγ enhance the amplitude of NMDA-induced inward currents in substantia gelatinosa neurons via microglial IFNγ receptors and CCL2/CCR2 signaling. This mechanism might be partially responsible for the development of persistent neuropathic pain.

Pharmacologic Inhibition of JAK1/JAK2 Signaling Reduces Experimental Murine Acute GVHD While Preserving GVT Effects.

Immune-mediated graft-versus-tumor (GVT) effects can occur after allogeneic hematopoietic stem cell transplantation (HSCT), but GVT is tightly linked to its main complication, graft-versus-host disease (GVHD). Strategies aimed at modulating GVHD, while maintaining the GVT effect, are needed to improve the cure rate of transplant. Given the emerging role of Janus-activated kinase (JAK) signaling in lymphoproliferative and myeloproliferative diseases and its established function at dictating T-cell differentiation, we postulated that JAKs might be potential therapeutic targets through a pharmacologic approach. We examined the effect of JAK1/JAK2 modulation by ruxolitinib in a mouse model of fully MHC mismatched bone marrow transplant comprising in vivo tumor inoculation. JAK1/JAK2 inhibition by ruxolitinib improved both overall survival (P = 0.03) and acute GVHD pathologic score at target organs (P ≤ 0.001) of treated mice. In addition, treatment with ruxolitinib was associated with a preserved GVT effect, as evidenced by reduction of tumor burden (P = 0.001) and increase of survival time (P = 0.01). JAK1/JAK2 inhibition did not impair the in vivo acquisition of donor T-cell alloreactivity; this observation may account, at least in part, to the preserved GVT effect. Rather, JAK1/JAK2 inhibition of GVHD was associated with the modulation of chemokine receptor expression, which may have been one factor in the reduced infiltration of donor T cells in GVHD target organs. These data provide further evidence that JAK inhibition represents a new and potentially clinically relevant approach to GVHD prevention.