Discovery and development of Janus kinase (JAK) inhibitors for inflammatory diseases

Design, synthesis, in vitro and in vivo biological evaluation of pterostilbene derivatives for anti-inflammation therapy

Pterostilbene (PST) is a naturally derived stilbene compound in grapes, blueberries, and other fruits. It is also a natural dietary compound with a wide range of biological activities such as antioxidant, anti-inflammatory, antitumor, and so on. Structural modifications based on the chemical scaffold of the pterostilbene skeleton are of great importance for drug discovery. In this study, pterostilbene skeletons were used to design novel anti-inflammatory compounds with high activity and low toxicity. A total of 30 new were found and synthesised, and their anti-inflammatory activity and safety were screened. Among them, compound E2 was the most active (against NO: IC50 = 0.7 μM) than celecoxib. Further studies showed that compound E2 exerted anti-inflammatory activity by blocking LPS-induced NF-κB/MAPK signalling pathway activation. In vivo experiments revealed that compound E2 had a good alleviating effect on acute colitis in mice. In conclusion, compound E2 may be a promising anti-inflammatory lead compound.

Leonurus japonicus Houtt. modulates neuronal apoptosis in intracerebral hemorrhage: Insights from network pharmacology and molecular docking

ETHNOPHARMACOLOGICAL RELEVANCE

Leonurus japonicus Houtt. (Labiatae), commonly known as Chinese motherwort, is a herbaceous flowering plant that is native to Asia. It is widely acknowledged in traditional medicine for its diuretic, hypoglycemic, antiepileptic properties and neuroprotection. Currently, Leonurus japonicus (Leo) is included in the Pharmacopoeia of the People's Republic of China. Traditional Chinese Medicine (TCM) recognizes Leo for its myriad pharmacological attributes, but its efficacy against ICH-induced neuronal apoptosis is unclear.

AIMS OF THE STUDY

This study aimed to identify the potential targets and regulatory mechanisms of Leo in alleviating neuronal apoptosis after ICH.

MATERIALS AND METHODS

The study employed network pharmacology, UPLC-Q-TOF-MS technique, molecular docking, pharmacodynamic studies, western blotting, and immunofluorescence techniques to explore its potential mechanisms.

RESULTS

Leo was found to assist hematoma absorption, thus improving the neurological outlook in an ICH mouse model. Importantly, molecular docking highlighted JAK as Leo's potential therapeutic target in ICH scenarios. Further experimental evidence demonstrated that Leo adjusts JAK1 and STAT1 phosphorylation, curbing Bax while augmenting Bcl-2 expression.

CONCLUSION

Leo showcases potential in mitigating neuronal apoptosis post-ICH, predominantly via the JAK/STAT mechanism.

Structural optimizations on the 7H-pyrrolo[2,3-d]pyrimidine scaffold to develop highly selective, safe and potent JAK3 inhibitors for the treatment of Rheumatoid arthritis

Janus Kinase 3 (JAK3) is important for the signaling transduction of cytokines in immune cells and is identified as potential target for treatment of rheumatoid arthritis (RA). Recently, we designed and synthesized two JAK3 inhibitors J1b and J1f, which featured with high selectivity but mild bioactivity. Therefore, in present study the structure was optimized to increase the potency. As shown in the results, most of the compounds synthesized showed stronger inhibitory activities against JAK3 in contrast to the lead compounds, among which 9a was the most promising candidate because it had the most potent effect in ameliorating carrageenan-induced inflammation of mice and exhibited low acute in vivo toxicity (MTD > 2 g/kg). Further analysis revealed that 9a was highly selective to JAK3 (IC50 = 0.29 nM) with only minimal effect on other JAK members (>3300-fold) and those kinases bearing a thiol in a position analogous to that of Cys909 in JAK3 (>150-fold). Meanwhile, the selectivity of JAK3 was also confirmed by PBMC stimulation assay, in which 9a irreversibly bound to JAK3 and robustly inhibited the signaling transduction with mild suppression on other JAKs. Moreover, it was showed that 9a could remarkably inhibited the proliferation of lymphocytes in response to concanavalin A and significantly mitigate disease severity in collagen induced arthritis. Therefore, present data indicate that compound 9a is a selective JAK3 inhibitor and could be a promising candidate for clinical treatment of RA.

Revisiting Structure-activity Relationships: Unleashing the potential of selective Janus kinase 1 inhibitors

Janus kinases (JAKs), a kind of non-receptor tyrosine kinases, the function has been implicated in the regulation of cell proliferation, differentiation and apoptosis, immune, inflammatory response and malignancies. Among them, JAK1 represents an essential target for modulating cytokines involved in inflammation and immune function. Rheumatoid arthritis, atopic dermatitis, ulcerative colitis and psoriatic arthritis are areas where approved JAK1 drugs have been applied for the treatment. In the review, we provided a brief introduction to JAK1 inhibitors in market and clinical trials. The structures of high active JAK1 compounds (IC50 ≤ 0.1 nM) were highlighted, with primary focus on structure-activity relationship and selectivity. Moreover, the druggability processes of approved drugs and high active compounds were analyzed. In addition, the issues involved in JAK1 compounds clinical application as well as strategies to surmount these challenges, were discussed.

Preventing and managing cardiovascular events in patients with inflammatory bowel diseases treated with small-molecule drugs, an international Delphi consensus

Janus kinase (JAK) inhibitors and sphingosine 1 phosphate (S1P) receptor modulators are small molecule drugs (SMDs) approved for IBD treatment. Their use in clinical practice might be limited due to cardiovascular concerns. We aimed to provide guidance on risk assessment, monitoring, and management strategies, aiming to minimize potential cardiovascular risks of SMDs and to facilitate an adequate shared decision-making. A systematic literature search was conducted, and proposed statements were prepared. A virtual consensus meeting was held, in which eleven IBD physicians and two cardiovascular specialists from ten countries attended. Proposed statements were voted upon in an anonymous manner. Agreement was defined as at least 75 % of participants voting as 'agree' with each statement. Consensus was reached for eighteen statements. Available evidence does not show a higher risk of cardiovascular events with JAK inhibitors in the overall IBD population, although it might be increased in patients with an unfavorable cardiovascular profile. S1P receptor modulators may be associated with a risk of bradycardia, atrioventricular blocks, and hypertension. Cardiovascular risk stratification should be done before initiation of SMDs. Although the risk of cardiovascular events in patients with IBD on SMDs appears to be low overall, caution should still be taken in certain scenarios.

Identification of novel covalent JAK3 inhibitors through consensus scoring virtual screening: integration of common feature pharmacophore and covalent docking

Accumulated research strongly indicates that Janus kinase 3 (JAK3) is intricately involved in the initiation and advancement of a diverse range of human diseases, underscoring JAK3 as a promising target for therapeutic intervention. However, JAK3 shows significant homology with other JAK family isoforms, posing substantial challenges in the development of JAK3 inhibitors. To address these limitations, one strategy is to design selective covalent JAK3 inhibitors. Therefore, this study introduces a virtual screening approach that combines common feature pharmacophore modeling, covalent docking, and consensus scoring to identify novel inhibitors for JAK3. First, common feature pharmacophore models were constructed based on a selection of representative covalent JAK3 inhibitors. The optimal qualitative pharmacophore model proved highly effective in distinguishing active and inactive compounds. Second, 14 crystal structures of the JAK3-covalent inhibitor complex were chosen for the covalent docking studies. Following validation of the screening performance, 5TTU was identified as the most suitable candidate for screening potential JAK3 inhibitors due to its higher predictive accuracy. Finally, a virtual screening protocol based on consensus scoring was conducted, integrating pharmacophore mapping and covalent docking. This approach resulted in the discovery of multiple compounds with notable potential as effective JAK3 inhibitors. We hope that the developed virtual screening strategy will provide valuable guidance in the discovery of novel covalent JAK3 inhibitors.

Pharmacokinetics and Exposure-Response Analyses to Support Dose Selection of Upadacitinib in Crohn's Disease

Upadacitinib, a selective Janus kinase inhibitor, is the first orally administered therapy approved for the treatment of Crohn's disease (CD). This work characterized the pharmacokinetics of upadacitinib in CD patients and evaluated the relationships between upadacitinib steady-state plasma exposures and efficacy as well as safety parameters during the 12-week induction and the 52-week maintenance periods, to provide dosing recommendations for the treatment of CD. Upadacitinib pharmacokinetics in CD patients administered the extended-release formulation were consistent with patient populations in other approved indications. None of the evaluated CD-specific patient characteristics (e.g., disease location and prior gastrointestinal surgeries) had a meaningful impact on upadacitinib pharmacokinetics. Exposure-response analyses during 12-week induction treatment showed that response across all evaluated efficacy end points were approaching a plateau at median plasma exposures associated with 45 mg QD. Analyses for the maintenance period demonstrated that 30 mg QD is predicted to provide an additional 8% to 10% benefit for endoscopic response and endoscopic remission compared with 15 mg QD in patients who failed biologics. The analyses for safety showed a statistically significant relationship between increasing upadacitinib plasma exposures and the percentage of patients experiencing >2 g/dL decrease in hemoglobin from Baseline during induction and showed shallow relationships for serious infections and herpes zoster during the maintenance period. These results demonstrated adequate absorption of the extended-release formulation of upadacitinib in CD patients. The exposure-response analyses confirmed that 45 mg QD dose maximized efficacy as induction treatment and supported the selection of 15 mg QD or 30 mg QD as the maintenance doses.

Deucravacitinib: moderate-to-severe plaque psoriasis preventable?

Psoriasis is a persistent, inflammatory, and autoimmune condition that is difficult to treat. Estimates of the prevalence of psoriasis in people range from 0.27 % (95 % confidence interval 0.17 to 0.36) to 11.4 %, depending on factors such as age, sex, geography, ethnicity, genetics, and environmental factors. While systemic treatments are typically required for patients with moderate-to-severe instances of psoriasis, topical therapies are frequently effective for treating minor forms. In fact, phototherapy is frequently constrained by logistical considerations, and conventional systemic therapies are frequently avoided due to contraindications or the danger of adverse outcomes. In order to better serve the patient and achieve a greater level of quality of life, especially in order to sustain long-term efficacy, there is still a need for innovative therapies, which are always welcomed. Deucravacitinib is a first-in-class oral tyrosine kinase 2 (TYK2) inhibitor that is extremely selective. Through an allosteric mechanism, it stabilises an inhibitory connection between the regulatory and catalytic domains of TYK2's pseudokinase regulatory domain, which is catalytically inactive. This can be used to treat a variety of immune-mediated conditions, such as inflammatory bowel disease, lupus, psoriatic arthritis, and psoriasis. US-FDA has approved this drug on 9 September 2022 for the treatment of adults with moderate-to-severe plaque psoriasis who are candidates for systemic therapy or phototherapy. This article aims to review the current knowledge on the efficacy and safety of deucravacitinib for the management of psoriasis.

Impact of Upadacitinib on Atopic Keratoconjunctivitis Exacerbated by Dupilumab Treatment in Atopic Dermatitis Patients: A Prospective Dermatological and Ophthalmological Clinical Evaluation in Common Clinical Practice

Introduction: Atopic dermatitis (AD) is a prevalent chronic inflammatory skin condition with a substantial impact on patients, particularly due to ocular involvement known as atopic keratoconjunctivitis (AKC). Current therapeutic approaches, such as dupilumab, often lead to conjunctivitis, prompting exploration of alternative treatments like upadacitinib. Methods: We collected dermatological and ophthalmological prospective clinical evaluations of six adults with moderate-to-severe AD, undergoing treatment with upadacitinib after discontinuation of dupilumab due to the onset of AKC during therapy and the worsening of dermatitis in particular in the head and neck region. Clinical evaluations, including EASI scores, itch and sleep NRS, DLQI, and ocular parameters, were performed at baseline (during screening assessment before switching to upadacitinib) and then at week 12 and week 24. Clinical evaluation of AKC was performed by a team of ophthalmologists. Results: Upadacitinib not only improved atopic dermatitis in terms of EASI, itching, and sleep NRS, but also demonstrated a notable reduction in ocular signs and symptoms, as indicated by the Visual Analogue Scale (VAS), the Efron scale, and the Ocular Surface Disease Index Symptom Severity (OSDISS) scores. Discussion: Our observation of common clinical practice underscores the substantial impact of biological and small-molecule therapies on AD, emphasizing the limitation posed by dupilumab-associated conjunctivitis. Switching to upadacitinib significantly improved both clinical and functional ocular outcomes, suggesting its potential as an alternative therapeutic option for AD patients with ocular involvement. Conclusion: The presented data provides insights into the complex interplay between systemic therapies and ocular manifestations in AD. Upadacitinib emerges as a promising option to address dupilumab-associated conjunctivitis, offering improved quality of life for patients.

Pharmacokinetic review of janus kinase inhibitors and its clinical implications for the management of rheumatoid arthritis

INTRODUCTION

In the realm of autoimmune rheumatic diseases, understanding JAK inhibitors (JAKi) nuances is vital. Baricitinib, tofacitinib, upaacitinib, filgotinib, and peficitinib exhibit subtle yet impactful pharmacokinetic (PK) and pharmacodynamic (PD) variations.

AREAS COVERED

This narrative review critically assesses PK and PD distinctions among globally approved JAKi for rheumatoid arthritis, which primarily guide clinical decisions in autoimmune diseases, particularly rheumatoid arthritis. It explores the intricate JAK-STAT signaling pathway, offering insights into JAKs' roles in inflammation, hematopoiesis, and immune homeostasis. Emphasis on PK parameters, including absorption, distribution, metabolism, and excretion, along with CYP3A4 drug interactions, is highlighted. The review underscores integrating PK and PD properties, considering patient-specific factors like hepatic and renal clearance, for judicious JAKi selection in RA and related autoimmune conditions. The literature has been collected from all available databases based on the review question.

EXPERT OPINION

Integrating PK and PD properties with patient-specific factors is pivotal for judicious JAKi selection. Recognizing disparities in PK and PD across diseases, ethnicities, and environmental factors is crucial for personalized JAKi choices. This expert opinion underscores the significance of a second compartment analysis, elucidating the interplay between PK and PD and its impact on JAKi efficacy.

The Metabolism and Disposition of Brepocitinib in Humans and Characterization of the Formation Mechanism of an Aminopyridine Metabolite

Brepocitinib is an oral once-daily Janus kinase 1 and Tyrosine kinase 2 selective inhibitor currently in development for the treatment of several autoimmune disorders. Mass balance and metabolic profiles were determined using accelerator mass spectrometry in six healthy male participants following a single oral 60 mg dose of 14C-brepocitinib (∼300 nCi). The average mass balance recovery was 96.7% ± 6.3%, with the majority of dose (88.0% ± 8.0%) recovered in urine and 8.7% ± 2.1% of the dose recovered in feces. Absorption of brepocitinib was rapid, with maximal plasma concentrations of total radioactivity and brepocitinib achieved within 0.5 hours after dosing. Circulating radioactivity consisted primarily of brepocitinib (47.8%) and metabolite M1 (37.1%) derived from hydroxylation at the C5' position of the pyrazole ring. Fractional contributions to metabolism via cytochrome P450 enzymes were determined to be 0.77 for CYP3A4/5 and 0.14 for CYP1A2 based on phenotyping studies in human liver microsomes. However, additional clinical studies are required to understand the potential contribution of CYP1A1. Approximately 83% of the dose was eliminated as N-methylpyrazolyl oxidative metabolites, with 52.1% of the dose excreted as M1 alone. Notably, M1 was not observed as a circulating metabolite in earlier metabolic profiling of human plasma from a multiple ascending dose study with unlabeled brepocitinib. Mechanistic studies revealed that M1 was highly unstable in human plasma and phosphate buffer, undergoing chemical oxidation leading to loss of the 5-hydroxy-1-methylpyrazole moiety and formation of aminopyrimidine cleavage product M2. Time-dependent inhibition and trapping studies with M1 yielded insights into the mechanism of this unusual and unexpected instability. SIGNIFICANCE STATEMENT: This study provides a detailed understanding of the disposition and metabolism of brepocitinib, a JAK1/TYK2 inhibitor for atopic dermatitis, in humans as well as characterization of clearance pathways and pharmacokinetics of brepocitinib and its metabolites.

Discovery of GLPG3667, a Selective ATP Competitive Tyrosine Kinase 2 Inhibitor for the Treatment of Autoimmune Diseases

Tyrosine kinase 2 (TYK2) mediates cytokine signaling through type 1 interferon, interleukin (IL)-12/IL-23, and the IL-10 family. There appears to be an association between TYK2 genetic variants and inflammatory conditions, and clinical evidence suggests that selective inhibition of TYK2 could produce a unique therapeutic profile. Here, we describe the discovery of compound 9 (GLPG3667), a reversible and selective TYK2 adenosine triphosphate competitive inhibitor in development for the treatment of inflammatory and autoimmune diseases. The preclinical pharmacokinetic profile was favorable, and TYK2 selectivity was confirmed in peripheral blood mononuclear cells and whole blood assays. Dermal ear inflammation was reduced in an IL-23-induced in vivo mouse model of psoriasis. GLPG3667 also completed a phase 1b study (NCT04594928) in patients with moderate-to-severe psoriasis where clinical effect was shown within the 4 weeks of treatment and it is now in phase 2 trials for the treatment of dermatomyositis (NCT05695950) and systemic lupus erythematosus (NCT05856448).

JAK-STAT Signaling and Beyond in the Pathogenesis of Spondyloarthritis and Their Clinical Significance

PURPOSE OF REVIEW

Janus kinase-signal transducers and activators of transcription cell signaling proteins (JAK-STATs) play a key regulatory role in functioning of several inflammatory cytokines. JAK-STAT signaling proteins are the key regulators of the cytokine/cytokine receptor system involved in the pathogenesis of various autoimmune disease including spondyloarthritis (SpA). This article mainly highlights the JAK-STAT signaling system, its association with the relevant cytokine/cytokine-receptor system, and its regulatory role in pathogenesis of SpA. Also, we have briefly addressed the principle for the use JAKi in SpA and the current status of use of JAK inhibitors (JAKi) in SpA.

RECENT FINDINGS

Recent developments with newer JAK molecules as well as other molecules beyond JAK inhibitors are now an exciting field for the development of novel therapies for autoimmune diseases and various malignant conditions. In this article, we have provided a special emphasis on how various cell signaling systems beyond JAK/STAT pathway are relevant to SpA and have provided a comprehensive review on this upcoming field in respect to the novel TYK2 inhibitors, RORγT inhibitors, mTOR inhibitors, NGF inhibitors, and various STAT kinase inhibitors. SpA are a group of autoimmune diseases with multifactorial etiologies. SpA is linked with genetic predisposition, environmental risk factors, and the immune system-mediated systemic inflammation. Here, we have provided the regulatory role of JAK/STAT pathway and other intracellular signaling system in the pathogenesis of SpA and its therapeutic relevance.

Small molecule drug discovery targeting the JAK-STAT pathway

The Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway functions as a central hub for transmitting signals from more than 50 cytokines, playing a pivotal role in maintaining hematopoiesis, immune balance, and tissue homeostasis. Dysregulation of this pathway has been implicated in various diseases, including immunodeficiency, autoimmune conditions, hematological disorders, and certain cancers. Proteins within this pathway have emerged as effective therapeutic targets for managing these conditions, with various approaches developed to modulate key nodes in the signaling process, spanning from receptor engagement to transcription factor activation. Following the success of JAK inhibitors such as tofacitinib for RA treatment and ruxolitinib for managing primary myelofibrosis, the pharmaceutical industry has obtained approvals for over 10 small molecule drugs targeting the JAK-STAT pathway and many more are at various stages of clinical trials. In this review, we consolidate key strategies employed in drug discovery efforts targeting this pathway, with the aim of contributing to the collective understanding of small molecule interventions in the context of JAK-STAT signaling. We aspire that our endeavors will contribute to advancing the development of innovative and efficacious treatments for a range of diseases linked to this pathway dysregulation.

Design and synthesis of highly selective Janus kinase 3 covalent inhibitors for the treatment of rheumatoid arthritis

Selective inhibition of Janus kinase 3 (JAK3) is a promising strategy for the treatment of autoimmune diseases. Based on the discovery of a hydrophobic pocket unutilized between the lead compound RB1 and the JAK3 protein, a series of covalent JAK3 inhibitors were prepared by introducing various aromatic fragments to RB1. Among them, J1b (JAK3 IC50 = 7.2 nM, other JAKs IC50 > 1000 nM) stood out because of its low toxicity (MTD > 2 g/kg) and superior anti-inflammatory activity in Institute of Cancer Research mice. Moreover, the acceptable bioavailability (F% = 31.69%) ensured that J1b displayed excellent immune regulation in collagen-induced arthritis mice, whose joints in the high-dose group were almost recovered to a normal state. Given its clear kinase selectivity (Bmx IC50 = 539.9 nM, other Cys909 kinases IC50 > 1000 nM), J1b was nominated as a highly selective JAK3 covalent inhibitor, which could be used to safely treat arthritis and other autoimmune diseases.

Tofacitinib and peficitinib inhibitors of Janus kinase for autoimmune disease treatment: a quantum biochemistry approach

Autoimmune inflammatory diseases, such as rheumatoid arthritis (RA) and ulcerative colitis, are associated with an uncontrolled production of cytokines leading to the pronounced inflammatory response of these disorders. Their therapy is currently focused on the inhibition of cytokine receptors, such as the Janus kinase (JAK) protein family. Tofacitinib and peficitinib are JAK inhibitors that have been recently approved to treat rheumatoid arthritis. In this study, an in-depth analysis was carried out through quantum biochemistry to understand the interactions involved in the complexes formed by JAK1 and tofacitinib or peficitinib. Computational analyses provided new insights into the binding mechanisms between tofacitinib or peficitinib and JAK1. The essential amino acid residues that support the complex are also identified and reported. Additionally, we report new interactions, such as van der Waals; hydrogen bonds; and alkyl, pi-alkyl, and pi-sulfur forces, that stabilize the complexes. The computational results revealed that peficitinib presents a similar affinity to JAK1 compared to tofacitinib based on their interaction energies.

PCV2 Induced Endothelial Derived IL-8 Affects MoDCs Maturation Mainly via NF-κB Signaling Pathway

Porcine circovirus type 2 (PCV2) infection can cause immunosuppressive diseases in pigs. Vascular endothelial cells (VECs), as the target cells for PCV2, play an important role in the immune response and inflammatory regulation. Endothelial IL-8, which is produced by porcine hip artery endothelial cells (PIECs) infected with PCV2, can inhibit the maturation of monocyte-derived dendritic cells (MoDCs). Here, we established a co-culture system of MoDCs and different groups of PIECs to further investigate the PCV2-induced endothelial IL-8 signaling pathway that drives the inhibition of MoDC maturation. The differentially expressed genes related to MoDC maturation were mainly enriched in the NF-κB and JAK2-STAT3 signaling pathways. Both the NF-κB related factor RELA and JAK2-STAT3 signaling pathway related factors (IL2RA, JAK, STAT2, STAT5, IL23A, IL7, etc.) decreased significantly in the IL-8 up-regulated group, and increased significantly in the down-regulated group. The expression of NF-κB p65 in the IL-8 up-regulated group was reduced significantly, and the expression of IκBα was increased significantly. Nuclear translocation of NF-κB p65 was inhibited, while the nuclear translocation of p-STAT3 was increased in MoDCs in the PCV2-induced endothelial IL-8 group. The results of treatment with NF-κB signaling pathway inhibitors showed that the maturation of MoDCs was inhibited and the expression of IL-12 and GM-CSF at mRNA level were lower. Inhibition of the JAK2-STAT3 signaling pathway had no significant effect on maturation, and the expression of IL-12 and GM-CSF at mRNA level produced no significant change. In summary, the NF-κB signaling pathway is the main signaling pathway of MoDC maturation, and is inhibited by the PCV2-induced up-regulation of endothelial-derived IL-8.

A panel of janus kinase inhibitors identified with anti-inflammatory effects protect mice from lethal influenza virus infection

Influenza remains a significant threat to public health. In severe cases, excessive inflammation can lead to severe pneumonia or acute respiratory distress syndrome, contributing to patient morbidity and mortality. While antivirals can be effective if administered early, current anti-inflammatory drugs have limited success in treating severe cases. Therefore, discovering new anti-inflammatory agents to inhibit influenza-related inflammatory diseases is crucial. Herein, we screened a drug library with known targets using a human monocyte U937 infected with the influenza virus to identify novel anti-inflammatory agents. We also evaluated the anti-inflammatory effects of the hit compounds in an influenza mouse model. Our research revealed that JAK inhibitors exhibited a higher hit rate and more potent inhibition effect than inhibitors targeting other drug targets in vitro. Of the 22 JAK inhibitors tested, 15 exhibited robust anti-inflammatory activity against influenza virus infection in vitro. Subsequently, we evaluated the efficacy of 10 JAK inhibitors using an influenza mouse model and observed that seven provided protection ranging from 40% to 70% against lethal influenza virus infection. We selected oclacitinib as a representative compound for an extensive study to further investigate the in vivo therapeutic potential of JAK inhibitors for severe influenza-associated inflammation. Our results revealed that oclacitinib effectively suppressed neutrophil and macrophage infiltration, reduced pro-inflammatory cytokine production, and ultimately mitigated lung injury in mice infected with lethal influenza virus without impacting viral titer. These findings suggest that JAK inhibitors can modulate immune responses to influenza virus infection and may serve as potential treatments for influenza.IMPORTANCEAntivirals exhibit limited efficacy in treating severe influenza when not administered promptly during the infection. Current steroidal and nonsteroidal anti-inflammatory drugs demonstrate restricted effectiveness against severe influenza or are associated with significant side effects. Therefore, there is an urgent need for novel anti-inflammatory agents that possess high potency and minimal adverse reactions. In this study, 15 JAK inhibitors were identified through a screening process based on their anti-inflammatory activity against influenza virus infection in vitro. Remarkably, 7 of the 10 selected inhibitors exhibited protective effects against lethal influenza virus infection in mice, thereby highlighting the potential therapeutic value of JAK inhibitors for treating influenza.

Comprehensive overview of novel chemical drugs for ulcerative colitis: focusing on phase 3 and beyond

INTRODUCTION

Despite the growing number of highly efficacious biologics and chemical drugs for ulcerative colitis (UC), steroid-free disease control is still difficult to achieve in subgroups of patients due to refractoriness, adverse events, primary or secondary failure. New treatments are therefore still required in order to optimize clinical management of patients with UC.

AREAS COVERED

The efficacy and safety of both currently available and newly developed small molecules have been summarized. The PubMed database and clinicaltrials.gov were considered in order to search for phase 2b and 3 trials on new chemical drugs for UC. The study drugs reviewed included Janus kinases (JAK) and sphingosine-1-phosphate receptor (S1Pr) inhibitors, α4 integrin antagonist, and micro-RNA-124 upregulators.

EXPERT OPINION

Rapidity of onset, low immunogenicity, and safety are the main characteristics of small molecules currently available or under evaluation for treatment patients with UC. Among the currently available chemical drugs, the selective JAK and the S1Pr inhibitors are characterized by a good safety profile combined with the ability to induce clinical remission in UC. A relatively low frequency of endoscopic improvement and healing currently appears associated with their use, being higher in UC patients treated with S1Pr inhibitor Etrasimod. Overall, additional new safe and effective drugs are still required in order to optimize disease control in a larger majority of UC patients.

Shared genetic architecture between hypothyroidism and rheumatoid arthritis: A large-scale cross-trait analysis

BACKGROUND

In recent years, mounting evidence has indicated a co-morbid relationship between hypothyroidism and rheumatoid arthritis (RA), however, the shared genetic factors underlying this association remain unclear. This study aims to investigate the common genetic architecture between hypothyroidism and RA.

METHODS

Genome-wide association study (GWAS) summary statistics from recently published studies were utilized to examine the genetic correlation, shared genetic loci, and potential causal relationship between hypothyroidism and RA. Statistical methods included linkage disequilibrium score regression (LDSC), high-definition likelihood (HDL), cross-trait meta-analyses, colocalization analysis, multi-marker analysis of genomic annotation (MAGMA), tissue-specific enrichment analysis (TSEA), functional enrichment analysis, and latent causal variable method (LCV).

RESULTS

Our study demonstrated a significant genetic correlation between hypothyroidism and RA(LDSC:rg=0.3803,p=7.23e-11;HDL:rg=0.3849,p=1.02e-21). Through cross-trait meta-analysis, we identified 1035 loci, including 43 novel genetic loci. By integrating colocalization analysis and the MAGMA algorithm, we found a substantial number of genes, such as PTPN22, TYK2, and CTLA-4, shared between the two diseases, which showed significant enrichment across 14 tissues. These genes were primarily associated with the regulation of alpha-beta T cell proliferation, positive regulation of T cell activation, positive regulation of leukocyte cell-cell adhesion, T cell receptor signaling pathway, and JAK-STAT signaling pathway. However, our study did not reveal a significant causal association between the two diseases using the LCV approach.

CONCLUSION

Based on these findings, there is a significant genetic correlation between hypothyroidism and RA, suggesting a shared genetic basis for these conditions.

Continued JAK inhibitor treatment on the risk of recurrent herpes zoster reactivation in patients with immune-mediated inflammatory diseases: A nationwide population-based study in South Korea

BACKGROUND

To investigate the risk of recurrent herpes zoster (HZ) reactivation under continued Janus kinase inhibitor (JAKi) therapy in patients with immune-mediated inflammatory diseases (IMID) who developed HZ reactivation.

METHODS

Data from the Korean Health Insurance Review and Assessment Service (HIRA) of patients with rheumatoid arthritis (RA) or ulcerative colitis (UC) gathered from 2007 to 2021 were analyzed.

RESULTS

A total of 3947 (RA 3540, UC 407) receiving JAKi were included. After median 0.95 years (IQR, 0.93-2.58) of therapy, 611 (15.5%) patients developed HZ reactivation (incidence rate: 8.38/100 person-years [PY]). After excluding 151 patients with lack of data after HZ reactivation, 460 patients (JAKi continuation group, n = 386 [83.9%]; JAKi discontinuation group, n = 74 [16.1%]) were analyzed for the risk of subsequent recurrent HZ reactivation. During further follow-up of median 1.11 years (IQR, 0.53-1.91), 36 (9.3%) and 6 (8.1%) patients in the JAKi continuation group and JAKi discontinuation group experienced a recurrence of HZ, respectively. The incidence rate of subsequent recurrent HZ reactivation was not significantly different between the two groups (5.3/100 vs. 5.9/100 PY; P = 0.52). After adjusting for age, sex, usage of corticosteroids, and antiviral agents, continued use of JAKi was not a significant risk factor for subsequent HZ reactivation (adjusted hazard ratio, 0.71 [CI, 0.29-1.72], P = 0.45).

CONCLUSION

In this nationwide population-based study on patients with RA or UC, continued use of JAKi was not associated with a significant risk of subsequent recurrent HZ reactivation. JAKi therapy may be maintained in patients with IMID even after HZ reactivation.

Design, synthesis and evaluation of C-5 substituted pyrrolopyridine derivatives as potent Janus Kinase 1 inhibitors with excellent selectivity

The development of highly selective Janus Kinase 1 (JAK1) inhibitors is crucial for improving efficacy and minimizing adverse effects in the clinical treatment of autoimmune diseases. In a prior study, we designed a series of C-5 4-pyrazol substituted pyrrolopyridine derivatives that demonstrated significant potency against JAK1, with a 10 ∼ 20-fold selectivity over Janus Kinase 2 (JAK2). Building on this foundation, we adopted orthogonal strategy by modifying the C-5 position with 3-pyrazol/4-pyrazol/3-pyrrol groups and tail with substituted benzyl groups on the pyrrolopyridine head to enhance both potency and selectivity. In this endeavor, we have identified several compounds that exhibit excellent potency and selectivity for JAK1. Notably, compounds 12b and 12e, which combined 4-pyrazol group at C-5 site and meta-substituted benzyl tails, displayed IC50 value with 2.4/2.2 nM and high 352-/253-fold selectivity for JAK1 over JAK2 in enzyme assays. Additionally, both compounds showed good JAK1-selective in Ba/F3-TEL-JAK1/2 cell-based assays. These findings mark a substantial improvement, as these compounds are 10-fold more potent and over 10-fold more selective than the best compound identified in our previous study. The noteworthy potency and selectivity properties of compounds 12b and 12e suggest their potential utility in furthering the development of drugs for autoimmune diseases.

Ferulic acid protects against gamma-radiation induced liver injury via regulating JAK/STAT/Nrf2 pathways

This study aims to evaluate the effect and underlying mechanism of ferulic acid (FA) in alleviating the acute liver injury by ionizing radiation (IR) in vivo. Rats were divided into 4groups (Groups: control, 6Gy irradiated (IRR), FA (50 mg/kg) and FA + IRR). The results showed that FA can effectively inhibit liver damage and restore the structure and function of the liver. In mechanism, FA prevented IR-induced liver fibrosis and blocked the JAK/STAT signaling pathway to effectively inhibit the hepatic inflammatory response; and inhibited IR-induced oxidative stress (OS) by upregulating the Nrf2 signaling pathway and promoting the synthesis of several antioxidants. Moreover, FA inhibited ferroptosis in the liver by stimulating the expression of GPX4 and SLC7A11. FA reduced lipid peroxidation by downregulation of the reactive oxygen species (ROS) production and iron aggregation, thus inhibiting ferroptosis and alleviating IR-induced liver injury. In conclusion, the current study suggests the potential complex mechanisms underlying the mitigating impact of FA in IR-induced ferroptotic liver damage.

Upadacitinib in Crohn's disease

INTRODUCTION

The small molecule and oral selective and reversible Janus kinase (JAK) inhibitor upadacitinib has been approved for the treatment of moderate to severe active Crohn's disease (CD) in adult patients since April 2023 by EMA/FDA.

AREAS COVERED

The approval is based on the two induction studies a maintenance study showing that upadacitinib induction and maintenance therapy was superior to placebo. The approval of upadacitinib in CD expands the therapeutic armamentarium for the management of inflammatory bowel diseases (IBD). Upadacitinib is the first and only JAK inhibitor approved in patients with CD and provides a novel mechanism of action and the first advanced oral treatment option for patients with CD. Upadacitinib is approved for the treatment of other immunologically mediated disorders, including ulcerative colitis, rheumatoid arthritis, psoriasis arthritis, axial spondylarthritis, ankylosing spondylitis, and atopic dermatitis. Treatment of atopic dermatitis has been approved from the age of 12 years.

EXPERT OPINION

Upadacitinib may cause relevant changes of our current treatment algorithms for Crohn's disease. Further real-world studies and head-to-head comparisons are needed to position upadacitinib in our current treatment algorithms for CD.

Application of JAK inhibitors in paradoxical reaction through immune-related dermatoses

Biologics play a positive and effective role in the treatment of immune-related dermatoses. However, many other immune-related diseases have also manifested along with biologics treatment. Paradoxical reaction through immune-related dermatoses refer to the new onset or exacerbation of other immune-mediated dermatoses (mainly psoriasis and atopic dermatitis) after biologics treatment of inflammatory dermatoses (mainly psoriasis and atopic dermatitis), such as new atopic dermatitis (AD) in psoriasis (PsO) treatment and new PsO in AD treatment. A common genetic background and Inflammatory pathway are possible pathogenesis. Faced with paradoxical reactions, the choice of therapy needs to be directed toward therapies effective for both diseases, such as Janus kinase (JAK) inhibitors. The Janus kinase and signal transducer and activator of transcription (JAK-STAT) pathway plays an important role in the inflammatory pathway, and has been widely used in the treatment of AD and PsO in recent years. This article focuses on JAK inhibitors such as tofacitinib, baricitinib, ruxolitinib, Abrocitinib, upadacitinib, and deucravacitinib, to explore the possible application in treatment of paradoxical reactions. Common side effects, baseline risk factors and safety use of JAK inhibitors were discussed.

High-Resolution Structure of RNA G-Quadruplex Containing Unique Structural Motifs Originating from the 5'-UTR of Human Tyrosine Kinase 2 (TYK2)

Tyrosine kinase 2 (TYK2) is a member of the JAK family of nonreceptor-associated tyrosine kinases together with highly homologous JAK1, JAK2, and JAK3 paralogues. Overexpression of TYK2 is associated with several inflammatory diseases, including severe complications during the COVID-19 infection. Since the downregulation of JAK paralogues could lead to serious health consequences or even death, it is critical to avoid it when designing drugs to suppress TYK2. To achieve the required specificity only for TYK2, researchers have recently selectively targeted TYK2 mRNA by developing antisense oligonucleotides. In this work, we expand the target space of TYK2 mRNA by showing that the mRNA adopts tetra-helical noncanonical structures called G-quadruplexes. We identified a TYKwt RNA oligonucleotide from the 5'-UTR of TYK2 mRNA, which adopts multiple different parallel G-quadruplexes that exist at equilibrium. Using NMR spectroscopy, we showed that some of the G-quadruplexes adopt unique structural motifs, mainly due to the formation of a stable GA bulge. Using guanine to uridine substitutions, we prepared the oligonucleotide TYK3_U6, which serves as an excellent model for the bulged G-quadruplexes formed by the TYKwt oligonucleotide. NMR structural analysis, including data on the residual coupling constants (RDC) of the loop regions, unveiled that the studied three-quartet parallel G-quadruplex contains many unusual structural features such as a G(U)A bulge, a guanine residue in the syn conformation, A and U residues stacked on the top G-quartet, and a well-defined adenine from a three-residue long propeller loop oriented in the groove, all of which could be valuable targets for future drug design.

Large-scale comparison of machine learning methods for profiling prediction of kinase inhibitors

Conventional machine learning (ML) and deep learning (DL) play a key role in the selectivity prediction of kinase inhibitors. A number of models based on available datasets can be used to predict the kinase profile of compounds, but there is still controversy about the advantages and disadvantages of ML and DL for such tasks. In this study, we constructed a comprehensive benchmark dataset of kinase inhibitors, involving in 141,086 unique compounds and 216,823 well-defined bioassay data points for 354 kinases. We then systematically compared the performance of 12 ML and DL methods on the kinase profiling prediction task. Extensive experimental results reveal that (1) Descriptor-based ML models generally slightly outperform fingerprint-based ML models in terms of predictive performance. RF as an ensemble learning approach displays the overall best predictive performance. (2) Single-task graph-based DL models are generally inferior to conventional descriptor- and fingerprint-based ML models, however, the corresponding multi-task models generally improves the average accuracy of kinase profile prediction. For example, the multi-task FP-GNN model outperforms the conventional descriptor- and fingerprint-based ML models with an average AUC of 0.807. (3) Fusion models based on voting and stacking methods can further improve the performance of the kinase profiling prediction task, specifically, RF::AtomPairs + FP2 + RDKitDes fusion model performs best with the highest average AUC value of 0.825 on the test sets. These findings provide useful information for guiding choices of the ML and DL methods for the kinase profiling prediction tasks. Finally, an online platform called KIPP ( https://kipp.idruglab.cn ) and python software are developed based on the best models to support the kinase profiling prediction, as well as various kinase inhibitor identification tasks including virtual screening, compound repositioning and target fishing.

Expanding the ligandable proteome by paralog hopping with covalent probes

More than half of the ~20,000 protein-encoding human genes have at least one paralog. Chemical proteomics has uncovered many electrophile-sensitive cysteines that are exclusive to a subset of paralogous proteins. Here, we explore whether such covalent compound-cysteine interactions can be used to discover ligandable pockets in paralogs that lack the cysteine. Leveraging the covalent ligandability of C109 in the cyclin CCNE2, we mutated the corresponding residue in paralog CCNE1 to cysteine (N112C) and found through activity-based protein profiling (ABPP) that this mutant reacts stereoselectively and site-specifically with tryptoline acrylamides. We then converted the tryptoline acrylamide-N112C-CCNE1 interaction into a NanoBRET-ABPP assay capable of identifying compounds that reversibly inhibit both N112C- and WT-CCNE1:CDK2 complexes. X-ray crystallography revealed a cryptic allosteric pocket at the CCNE1:CDK2 interface adjacent to N112 that binds the reversible inhibitors. Our findings thus provide a roadmap for leveraging electrophile-cysteine interactions to extend the ligandability of the proteome beyond covalent chemistry.

Medicinal chemistry perspective of JAK inhibitors: synthesis, biological profile, selectivity, and structure activity relationship

JAK-STAT signalling pathway was discovered more than quarter century ago. The JAK-STAT pathway protein is considered as one of the crucial hubs for cytokine secretion which mediates activation of different inflammatory, cellular responses and hence involved in different etiological factors. The various etiological factors involved are haematopoiesis, immune fitness, tissue repair, inflammation, apoptosis, and adipogenesis. The presence of the active mutation V617K plays a significant role in the progression of the JAK-STAT pathway-related disease. Consequently, targeting the JAK-STAT pathway could be a promising therapeutic approach for addressing a range of causative factors. In this current review, we provided a comprehensive discussion for the in-detail study of anatomy and physiology of the JAK-STAT pathway which contributes structural domain rearrangement, activation, and negative regulation associated with the downstream signaling pathway, relationship between different cytokines and diseases. This review also discussed the recent development of clinical trial entities. Additionally, this review also provides updates on FDA-approved drugs. In the current investigation, we have classified recently developed small molecule inhibitors of JAK-STAT pathway according to different chemical classes and we emphasized their synthetic routes, biological evaluation, selectivity, and structure-activity relationship.

Selectivity, efficacy and safety of JAKinibs: new evidence for a still evolving story

Fundamental insight gained over the last decades led to the discovery of cytokines as pivotal drivers of inflammatory diseases such as rheumatoid arthritis, psoriasis/psoriasis arthritis, inflammatory bowel diseases, atopic dermatitis and spondylarthritis. A deeper understanding of the pro-inflammatory and anti-inflammatory effects of various cytokines has prompted new cytokine-targeting therapies, which revolutionised the treatment options in the last years for patients with inflammatory disorders. Disease-associated immune responses typically involve a complex interplay of multiple cytokines. Therefore, blockade of one single cytokine does not necessarily lead to a persistent remission in all patients with inflammatory disorders and fostered new therapeutic strategies targeting intracellular pathways shared by multiple cytokines. By inhibiting JAK-STAT signalling pathways common to families of cytokines, JAK-inhibitors (JAKinibs) have created a new paradigm for the treatment of inflammatory diseases. Multiple agents have been approved for various disorders and more are being investigated for several new indications. Second-generation selective JAKinibs have been devised with the aim to achieve an increased selectivity and a possible reduced risk of side effects. In the current review, we will summarise the current body of evidence of pan versus selective JAKinibs and the most recent insights on new side effects and indications, including COVID-19.

Topical Delivery of Tofacitinib in Dermatology: The Promise of a Novel Therapeutic Class Using Biodegradable Dendritic Polyglycerol Sulfates

Inflammatory skin diseases, such as psoriasis, atopic dermatitis, and alopecia areata, occur when the regulatory tolerance of the innate immune system is disrupted, resulting in the activation of the Janus kinase-signal transducer and activator of transcription (JAK-STAT) inflammatory signaling pathway by interleukin 6 (IL-6) and other key inflammatory cytokines. JAK inhibitors, such as tofacitinib, bind to these enzymes which are coupled to receptors on cell surfaces and block the transcription of inflammatory cytokine-induced genes. The first topical applications are being marketed, yet insufficient effects regarding indications, such as alopecia areata, suggest that improved delivery technologies could help increase the efficacy. In this study, we used sulfated dendritic polyglycerol with caprolactone segments integrated in its backbone (dPGS-PCL), with a molecular weight of 54 kDa, as a degradable carrier to load and solubilize the hydrophobic drug tofacitinib (TFB). TFB loaded in dPGS-PCL (dPGS-PCL@TFB), at a 11 w/w% loading capacity in aqueous solution, showed in an ex-vivo human skin model better penetration than free TFB in a 30:70 (v/v) ethanol/water mixture. We also investigated the anti-inflammatory efficacy of dPGS-PCL@TFB (0.5 w/w%), dPGS-PCL, and free TFB in the water/ethanol mixture by measuring their effects on IL-6 and IL-8 release, and STAT3 and STAT5 activation in ex vivo skin models of simulated inflamed human skin. Our results suggest that dPGS-PCL@TFB reduces the activation of STAT3 and STAT5 by increasing the penetration of the tofacitinib. However, no statistically significant differences with respect to the inhibition of IL-6 and IL-8 were observed in this short incubation time.

Comprehending the intermolecular interaction of JAK inhibitor fedratinib with bovine serum albumin (BSA)/human alpha-1-acid glycoprotein (HAG): Multispectral methodologies and molecular simulation

The primary coverage of this paper is to investigate the molecular interaction of JAK2 inhibitor, fedratinib (FED) with BSA/HAG proteins through multispectral approaches and molecular docking as well as MD calculation. Arrival at a conclusion, the endogenous fluorescence of BSA/HAG protein was quenched separately in the form of static and mixed quenching. The FED-BSA and FED-HAG complexes with the stoichiometric ratio of 1:1 were formed in the interaction process. And, The Kb values of these complexes were of 104-105 M-1 and 105-106 M-1, respectively, representing that the FED-HAG complex exhibited a comparatively high affinity compared to the FED-BSA complex. It is confimed that FED inserted into the interface area between subdomain IIA and IIB of BSA (marked as site II') and the bucket-shaped hydrophobic cavity of HAG, respectively, resulting in the slight alteration in the secondary structure of BSA/HAG and the micro-environment round Tyr and Trp residues. The expetimental results also confirmed that van der Waals forces (VDW), hydrogen bonds and hydrophobic interaction played a dominant role in the formation of two stable complexes. The above experimental results were supplemented and verified through molecular docking and MD simulation. Meanwhile, the effects of common ions on affinity were explored. This study could shine a light on evaluating the pharmacological properties of the JAK inhibitor FED, understanding the distribution and operation of the drug in the body, and leading to the development of the creation of novel medication devise.

Baricitinib and tofacitinib off-target profile, with a focus on Alzheimer's disease

INTRODUCTION

Janus kinase (JAK) inhibitors were recently identified as promising drug candidates for repurposing in Alzheimer's disease (AD) due to their capacity to suppress inflammation via modulation of JAK/STAT signaling pathways. Besides interaction with primary therapeutic targets, JAK inhibitor drugs frequently interact with unintended, often unknown, biological off-targets, leading to associated effects. Nevertheless, the relevance of JAK inhibitors' off-target interactions in the context of AD remains unclear.

METHODS

Putative off-targets of baricitinib and tofacitinib were predicted using a machine learning (ML) approach. After screening scientific literature, off-targets were filtered based on their relevance to AD. Targets that had not been previously identified as off-targets of baricitinib or tofacitinib were subsequently tested using biochemical or cell-based assays. From those, active concentrations were compared to bioavailable concentrations in the brain predicted by physiologically based pharmacokinetic (PBPK) modeling.

RESULTS

With the aid of ML and in vitro activity assays, we identified two enzymes previously unknown to be inhibited by baricitinib, namely casein kinase 2 subunit alpha 2 (CK2-α2) and dual leucine zipper kinase (MAP3K12), both with binding constant (K d) values of 5.8 μM. Predicted maximum concentrations of baricitinib in brain tissue using PBPK modeling range from 1.3 to 23 nM, which is two to three orders of magnitude below the corresponding binding constant.

CONCLUSION

In this study, we extended the list of baricitinib off-targets that are potentially relevant for AD progression and predicted drug distribution in the brain. The results suggest a low likelihood of successful repurposing in AD due to low brain permeability, even at the maximum recommended daily dose. While additional research is needed to evaluate the potential impact of the off-target interaction on AD, the combined approach of ML-based target prediction, in vitro confirmation, and PBPK modeling may help prioritize drugs with a high likelihood of being effectively repurposed for AD.

Highlights

This study explored JAK inhibitors' off-targets in AD using a multidisciplinary approach.We combined machine learning, in vitro tests, and PBPK modelling to predict and validate new off-target interactions of tofacitinib and baricitinib in AD.Previously unknown inhibition of two enzymes (CK2-a2 and MAP3K12) by baricitinib were confirmed using in vitro experiments.Our PBPK model indicates that baricitinib low brain permeability limits AD repurposing.The proposed multidisciplinary approach optimizes drug repurposing efforts in AD research.

Target Occupancy and Functional Inhibition of JAK3 and TEC Family Kinases by Ritlecitinib in Healthy Adults: An Open-Label, Phase 1 Study

Ritlecitinib is a small molecule in clinical development that covalently and irreversibly inhibits Janus kinase 3 (JAK3) and the TEC family of kinases (BTK, BMX, ITK, TXK, and TEC). This phase 1, open-label, parallel-group study assessed target occupancy and functional effects of ritlecitinib on JAK3 and TEC family kinases in healthy participants aged 18-60 years who received 50 or 200 mg single doses of ritlecitinib on day 1. Blood samples to assess ritlecitinib pharmacokinetics, target occupancy, and pharmacodynamics were collected over 48 hours. Target occupancy was assessed using mass spectroscopy. Functional inhibition of JAK3-dependent signaling was measured by the inhibition of the phosphorylation of its downstream target signal transducer and activator of transcription 5 (pSTAT5), following activation by interleukin 15 (IL-15). The functional inhibition of Bruton's tyrosine kinase (BTK)-dependent signaling was measured by the reduction in the upregulation of cluster of differentiation 69 (CD69), an early marker of B-cell activation, following treatment with anti-immunoglobulin D. Eight participants received one 50 mg ritlecitinib dose and 8 participants received one 200 mg dose. Ritlecitinib plasma exposure increased in an approximately dose-proportional manner from 50 to 200 mg. The maximal median JAK3 target occupancy was 72% for 50 mg and 64% for 200 mg. Ritlecitinib 50 mg had >94% maximal target occupancy of all TEC kinases, except BMX (87%), and 200 mg had >97% for all TEC kinases. For BTK and TEC, ritlecitinib maintained high target occupancy throughout a period of 48 hours. Ritlecitinib reduced pSTAT5 levels following IL-15- and BTK-dependent signaling in a dose-dependent manner. These target occupancy and functional assays demonstrate the dual inhibition of the JAK3- and BTK-dependent pathways by ritlecitinib. Further studies are needed to understand the contribution to clinical effects of inhibiting these pathways.

Hexahydrocurcumin from Zingiberis rhizoma attenuates lipopolysaccharide-induced acute pneumonia through JAK1/STAT3 signaling pathway

BACKGROUND

Pneumonia is one of the major causes of death after pathogens infection. Zingiberis rhizoma (GAN JIANG) is a herb that used in combination with other Chinese medicines to treat pathogen such as virus induced pneumonia. However, the affect of hexahydrocurcumin (HHC), a component from Zingiberis rhizoma, on pneumonia remains unknown.

PURPOSE

This study aims to explore the effects of HHC on lipopolysaccharide (LPS)-induced acute pneumonia, and to clarify the underlying mechanism.

METHODS

The pneumonia model of C57BL/6 mice was established by intratracheal injection of LPS to evaluate the therapeutic effect of HHC on lung injury and inflammation in vivo. RAW264.7 macrophages were utilized to illustrate the cellular mechanism of HHC in vitro.

RESULTS

HHC alleviated lung injury, ROS and inflammatory cytokine IL-6 production in pneumonia mice in vivo. Molecular docking results disclosed the binding of HHC to JAK1 protein. The study further showed that HHC suppressed the inflammatory cytokines such as IL-6, TNF-α, IL-1β gene expression, inhibited the phosphorylation of JAK1 but not JAK3, and the subsequent STAT3 phosphorylation in LPS-activated macrophages. HHC exhibited no effects on the protein levels of JAK1 and STAT3 in vitro. Consistently, HHC also attenuated the JAK1, STAT3 phosphorylation in pneumonia mice in vivo.

CONCLUSION

The results reveal that HHC attenuates pneumonia by targeted inhibition of JAK1/STAT3 signaling pathway. It indicates the novel role of HHC to treat pneumonia, and its potential applications for JAK inhibitor-treated diseases.

A case in which baricitinib was effective for both rheumatoid arthritis and essential thrombocythemia

We experienced a case of rheumatoid arthritis and JAK2V617F mutation-positive essential thrombocythemia treated with baricitinib. The patient was a 72-year-old male. He was diagnosed with rheumatoid arthritis at a local clinic in April 2018. Methotrexate (MTX) was started and the dose was increased to 16 mg/week. In October of the same year, anaemia was observed and MTX was reduced, but anaemia progressed. Blood tests showed pancytopenia, and he was referred to Rheumatology on suspicion of drug-induced pancytopenia. Pancytopenia improved with discontinuation of MTX and administration of folic acid. His platelet count was markedly increased to 1,400,000/μl at one point, decreased to 400,000/μl, and then gradually increased to 700,000-1,000,000/μl. Despite taking an antiplatelet drug, he developed cerebral infarction in June 2019. The JAK2V617F mutation was noted, and he was diagnosed with essential thrombocythemia. Hydroxycarbamide was started, but the effect was insufficient. Baricitinib, a JAK1/2 inhibitor indicated for rheumatoid arthritis, was started in August with the expectation that it would also be effective for essential thrombocythemia. The platelet count decreased to ∼400,000-600,000 cells/μl, and a decrease in the C-reactive protein level and the improvement of arthritis were noted. We report this case because it is considered to be a valuable case, suggesting that baricitinib may be effective for essential thrombocythemia.

Discovery of novel dual Bruton's tyrosine kinase (BTK) and Janus kinase 3 (JAK3) inhibitors as a promising strategy for rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronically systemic autoimmune disorder, which is related with various cellular signal pathways. Both BTK (Bruton's Tyrosine Kinase) and JAK3 (Janus Kinase 3) play important roles in the pathogenesis of rheumatoid arthritis. Herein, we reported the discovery of dual BTK/JAK3 inhibitors through bioisosterism and computer-aided drug design based on the structure of BTK inhibitor ibrutinib. We reported the discovery of dual BTK/JAK3 inhibitors which are based on the structure of BTK inhibitor ibrutinib via the method of bioisosterism and computer-aided drug design) Most of the target compounds exhibited moderate to strong inhibitory activities against BTK and JAK3. Among them, compound XL-12 stood out as the most promising candidate targeting BTK and JAK3 with potent inhibitory activities (IC50 = 2.0 nM and IC50 = 14.0 nM respectively). In the in vivo studies, compound XL-12 (40 mg/kg) exhibited more potent antiarthritic activity than ibrutinib (10 mg/kg) in adjuvant arthritis (AA) rat model. Furthermore, compound XL-12 (LD50 > 1600 mg/kg) exerted improved safety compared with ibrutinib (LD50 = 750 mg/kg). These results indicated that compound XL-12, the dual BTK/JAK3 inhibitor, might be a potent drug candidate for the treatment of RA.

Identification and Biological Evaluation of a Potent and Selective JAK1 Inhibitor for the Treatment of Pulmonary Fibrosis

Janus kinase 1 (JAK1) plays a pivotal role in regulating inflammation and fibrosis via the JAK/STAT signaling pathway, making it a promising target for associated diseases. In this study, we explored the modification of an N-methyl 1H-pyrrolo[2,3-b]pyridine-5-carboxylate core, leading to the identification of 4-(((2S,4S)-1-(4-trifluoromethyl)-2-methylpiperidin-4-yl)amino)-N-methyl-1H-pyrrolo[2,3-b]pyridine-5-carboxamide (36b) as a highly potent and selective JAK1 inhibitor. Compound 36b exhibited an impressive IC50 value of 0.044 nM for JAK1 and demonstrated remarkable selectivity of 382-fold, 210-fold, and 1325-fold specificity over JAK2, JAK3, and TYK2, respectively. The kinase panel assays further confirmed its specificity, and cell-based experiments established its efficacy in inhibiting JAK1-STAT phosphorylation in human L-132 or SK-MES-1 cells. Pharmacokinetic studies revealed that compound 36b boasts an oral bioavailability exceeding 36%. In a bleomycin-induced fibrosis mouse model, compound 36b significantly reduced STAT3 phosphorylation, resulting in improvement in body weight and reduced collagen deposition, all achieved without significant side effects.

Novel Janus Kinase Inhibitors in the Treatment of Dermatologic Conditions

Janus kinase inhibitors, also known as JAK inhibitors, JAKinibs or JAKi, are a new group of disease-modifying drugs. They work by inhibiting enzymes involved in the transmission of information from receptors located in the cell membrane to the cell interior, specifically to the cell nucleus, thus disrupting the JAK-STAT pathway. This pathway plays a role in key cellular processes such as the immune response and cell growth. This feature is used in the treatment of patients with rheumatological, gastroenterological and hematological diseases. Recently, it has been discovered that JAK-STAT pathway inhibitors also show therapeutic potential against dermatological diseases such as atopic dermatitis, psoriasis, alopecia areata and acquired vitiligo. Studies are underway to use them in the treatment of several other dermatoses. Janus kinase inhibitors represent a promising class of drugs for the treatment of skin diseases refractory to conventional therapy. The purpose of this review is to summarize the latest knowledge on the use of JAKi in dermatological treatment.

Synthesis and clinical application of small-molecule inhibitors of Janus kinase

Janus kinase (JAK) plays a crucial role in intracellular signaling pathways, particularly in cytokine-mediated signal transduction, making them attractive therapeutic targets for a wide range of diseases, including autoimmune disorders, myeloproliferative neoplasms, and inflammatory conditions. The review provides a comprehensive overview of the development and therapeutic potential of small-molecule inhibitors targeting JAK family of proteins in various clinical trials. It also discusses the mechanisms of action, specificity, and selectivity of these inhibitors, shedding light on the challenges associated with achieving target selectivity while minimizing off-target effects. Moreover, the review offers insights into the clinical applications of JAK inhibitors, summarizing the ongoing clinical trials and the Food and Drug Administration (FDA)-approved JAK inhibitors currently available for various diseases. Overall, this review provides a thorough examination of the synthesis and clinical use of typical small-molecule JAK inhibitors in different clinical stages and offers a bright future for the development of novel small-molecule JAK inhibitors.

Anti-inflammatory effects of Allium cepa L. peel extracts via inhibition of JAK-STAT pathway in LPS-stimulated RAW264.7 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Allium cepa L. (A. cepa) is one of the oldest cultivated plants in the world. A. cepa has been used in traditional folk medicine to treat inflammatory disease in several regions, such as Palestine and Serbia. A. cepa peel has a higher content of flavonoids, such as quercetin, than the edible parts. These flavonoids alleviate inflammatory diseases. However, the anti-inflammatory effects of A. cepa peel extract-obtained using various extraction methods-and their underlying mechanisms require further investigation.

AIM OF THE STUDY

Although research to find safe anti-inflammatory substances in various natural products has been actively conducted for many years, it is important to continue identifying potential anti-inflammatory effects in natural materials. The purpose of this study was to investigate the ethnopharmacological properties of the A. cepa peel extract, whose efficacy when obtained through different extraction methods and underlying action mechanisms is not well known. The present study specifically aimed to observe the anti-inflammatory effects of the A. cepa peel extracts obtained using various extraction methods and the related detailed mechanisms of A. cepa peel extracts in lipopolysaccharide (LPS)-induced RAW264.7 cells.

MATERIALS AND METHODS

The total flavonoid content of the A. cepa peel extracts was determined the diethylene glycol colorimetric method and measured using a calibration curve prepared using quercetin as a standard solution. The antioxidant activity was evaluated using the ABTS assay, and cytotoxicity was measured using the MTT assay. NO production was measured using Griess reagent. Protein levels were measured by western blotting, and mRNA expression was measured by RT-qPCR. Secreted cytokines were analyzed using ELISA or cytokine arrays. In the GSE160086 dataset, we calculated Z-scores for individual genes of interest and displayed using a heat map.

RESULTS

Of the three A. cepa peel extracts obtained using different extraction methods, the A. cepa peel 50% EtOH extract (AP50E) was the most effective at inhibiting LPS-induced nitric oxide (NO) and inducible nitric oxide synthase (iNOS). Furthermore, AP50E significantly reduced the levels of pro-inflammation cytokines interleukin (IL)-1α, IL-1β, IL-6, and IL-27. Additionally, AP50E directly inhibited the Janus kinase-signaling transducer and activator of transcription (JAK-STAT) pathway.

CONCLUSIONS

These results showed that AP50E exhibited an anti-inflammatory effect in LPS-induced RAW264.7 mouse macrophages by directly inhibiting JAK-STAT signaling. Based on these findings, we propose AP50E as a potential candidate for the development of preventive or therapeutic agents against inflammatory diseases.

A gastrointestinal locally activating Janus kinase inhibitor to treat ulcerative colitis

In this study, we integrated machine learning (ML), structure-tissue selectivity-activity-relationship (STAR), and wet lab synthesis/testing to design a gastrointestinal (GI) locally activating JAK inhibitor for ulcerative colitis treatment. The JAK inhibitor achieves site-specific efficacy through high local GI tissue selectivity while minimizing the requirement for JAK isoform specificity to reduce systemic toxicity. We used the ML model (CoGT) to classify whether the designed compounds were inhibitors or noninhibitors. Then we used the regression ML model (MTATFP) to predict their IC50 against related JAK isoforms of predicted JAK inhibitors. The ML model predicted MMT3-72, which was retained in the GI tract, to be a weak JAK1 inhibitor, while MMT3-72-M2, which accumulated in only GI tissues, was predicted to be an inhibitor of JAK1/2 and TYK2. ML docking methods were applied to simulate their docking poses in JAK isoforms. Application of these ML models enabled us to limit our synthetic efforts to MMT3-72 and MMT3-72-M2 for subsequent wet lab testing. The kinase assay confirmed MMT3-72 weakly inhibited JAK1, and MMT3-72-M2 inhibited JAK1/2 and TYK2. We found that MMT3-72 accumulated in the GI lumen, but not in GI tissue or plasma, but released MMT3-72-M2 accumulated in colon tissue with minimal exposure in the plasma. MMT3-72 achieved superior efficacy and reduced p-STAT3 in DSS-induced colitis. Overall, the integration of ML, the structure-tissue selectivity-activity-relationship system, and wet lab synthesis/testing could minimize the effort in the optimization of a JAK inhibitor to treat colitis. This site-specific inhibitor reduces systemic toxicity by minimizing the need for JAK isoform specificity.

Clinical research progress of novel biologics for the treatment of lupus nephritis

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the loss of immune tolerance. Lupus nephritis (LN) is one of the most common manifestations of severe organ damage in SLE, and also an important cause of disability and death. Its pathogenesis is associated with immune abnormalities such as immune cells, cytokines, and immune complex deposition. Traditional immunosuppressive therapy has been unable to meet the treatment needs of patients while bringing them toxic effects. In recent years, targeted therapies have emerged, and several novel biologics have gradually entered people's sight. This review will briefly introduce the pathogenesis of LN and the mechanism of biological targets, and summarize and analyze the clinical trials of new biologics for treating LN. Although not all biologics show positive results in clinical trials, the experience learned from these trials can help researchers adjust and plan future trial programs to seek better treatment methods.

Tofacitinib in the treatment of primary Sjögren's syndrome-associated interstitial lung disease: study protocol for a prospective, randomized, controlled and open-label trial

INTRODUCTION

Tofacitinib, a selective inhibitor of JAK1 and/or JAK3, is considered to alleviate the pulmonary condition of primary Sjögren's syndrome (pSS)-associated interstitial lung disease (ILD) through its anti-inflammatory and antifibrotic effects.

METHODS AND ANALYSIS

This is a single-center, prospective, randomized, open-label trial. The trial will compare a 52-week course of oral tofacitinib with traditional therapy cyclophosphamide (CYC) combined with azathioprine (AZA) in the treatment of pSS-ILD. A total of 120 patients will be randomly assigned into two treatment groups with a 1:1 ratio and followed for 52 weeks from the first dose. The primary endpoint of the study is the increase of forced vital capacity (FVC) at 52 weeks. Secondary endpoints include high-resolution computed tomography (HRCT), diffusion capacity for carbon monoxide of the lung (DLCO), the Mahler dyspnea index, the health-related quality of life (HARQoL) score, the cough symptom score, EULAR Sjögren's syndrome disease activity index (ESSDAI), and safety.

DISCUSSION

This study will be the first randomized controlled trial to investigate tofacitinib compared to the traditional regimen of CYC in combination with AZA in the treatment of pSS-ILD, which will provide data on efficacy and safety and further elucidate the role of the JAK-STAT signaling pathway in the development of pSS-ILD.

ETHICS AND DISSEMINATION

Before starting the experiment, the research proposal, informed consent (ICF) and relevant documents in accordance with the ethical principles of the Helsinki Declaration and the relevant requirements of the local GCP rules for ethical approval shall be submitted to the ethics committee of the hospital. The ethical approval of this study is reviewed by the Ethics Committee of Tongji Hospital and the ethical approval number is 2021-LCYJ-007. When the experiment is completed, the results will also be disseminated to patients and the public through publishing papers in international medical journals.

TRIAL REGISTRATION

The study was registered on the Chinese Clinical Trial Registry, www.chictr.org.cn ; ID ChiCTR2000031389.

Discovery of WD-890: A novel allosteric TYK2 inhibitor for the treatment of multiple autoimmune diseases

Tyrosine kinase 2 (TYK2) as a member of Janus kinase (JAK) family, mainly mediates the signaling of type I interferons (IFN), interleukin-12 (IL-12) and interleukin-23 (IL-23), which has become an attractive target for treatment of immune and inflammatory diseases. However, the development of selective TYK2 inhibitors is challenging due to the high homology of the catalytic kinase domain among the JAK family members. Here, we report a novel and potent allosteric inhibitor, WD-890, which binds to the pseudokinase domain of TYK2 with high selectivity and inhibits its function. We accomplished a series of preclinical studies to demonstrate the therapeutic efficacy of WD-890 in four animal models: systemic lupus erythematosus (SLE), psoriasis, psoriatic arthritis (PsA), and inflammatory bowel disease (IBD). The pharmacokinetic and toxicology results further indicate that WD-890 has favorable absorption, distribution, metabolism, and excretion (ADME) properties and tolerable toxicity. In conclusion, our study shows that WD-890 could be a promising oral TYK2 inhibitor for future treatment of autoimmune diseases.

Potential drug repurposing of ruxolitinib to inhibit the JAK/STAT pathway for the treatment of patients with epithelial ovarian cancer

AIM

This review aimed to describe the potential for therapeutic targeting of the JAK/STAT signaling pathway by repurposing the clinically-approved JAK inhibitor ruxolitinib in the patients with epithelial ovarian cancer (OC) setting.

METHODS

We reviewed publications that focus on the inhibition of the JAK/STAT pathway in hematological and solid malignancies including OC.

RESULTS

Preclinical studies showed that ruxolitinib effectively reduces OC cell viability and metastasis and enhances the anti-tumor activity of chemotherapy drugs. There are a number of recent clinical trials exploring the role of JAK/STAT inhibition in solid cancers including OC. Early results have not adequately supported efficacy in solid tumors. However, there are preclinical data and clinical studies supporting the use of ruxolitinib in combination with both chemotherapy and other targeted drugs in OC setting.

CONCLUSION

Inflammatory conditions and persistent activation of the JAK/STAT pathway are associated with tumourigenesis and chemoresistance, and therapeutic blockade of this pathway shows promising results. For women with OC, clinical investigation exploring the role of ruxolitinib in combination with chemotherapy agents or other targeted therapeutics is warranted.

Targeting the Tyrosine Kinase 2 (TYK2) Pseudokinase Domain: Discovery of the Selective TYK2 Inhibitor ABBV-712

Tyrosine kinase 2 (TYK2) is a nonreceptor tyrosine kinase that belongs to the JAK family also comprising JAK1, JAK2, and JAK3. TYK2 is an attractive target for various autoimmune diseases as it regulates signal transduction downstream of IL-23 and IL-12 receptors. Selective TYK2 inhibition offers a differentiated clinical profile compared to currently approved JAK inhibitors. However, selectivity for TYK2 versus other JAK family members has been difficult to achieve with small molecules that inhibit the catalytically active kinase domain. Successful targeting of the TYK2 pseudokinase domain as a strategy to achieve isoform selectivity was recently exemplified with deucravacitinib. Described herein is the optimization of selective TYK2 inhibitors targeting the pseudokinase domain, resulting in the discovery of the clinical candidate ABBV-712 (21).

Discovery of the Potent and Selective Inhaled Janus Kinase 1 Inhibitor AZD4604 and Its Preclinical Characterization

JAK-STAT cytokines are critical in regulating immunity. Persistent activation of JAK-STAT signaling pathways by cytokines drives chronic inflammatory diseases such as asthma. Herein, we report on the discovery of a highly JAK1-selective, ATP-competitive series of inhibitors having a 1000-fold selectivity over other JAK family members and the approach used to identify compounds suitable for inhaled administration. Ultimately, compound 16 was selected as the clinical candidate, and upon dry powder inhalation, we could demonstrate a high local concentration in the lung as well as low plasma concentrations, suggesting no systemic JAK1 target engagement. Compound 16 has progressed into clinical trials. Using 16, we found JAK1 inhibition to be more efficacious than JAK3 inhibition in IL-4-driven Th2 asthma.

A hybrid energy-based and AI-based screening approach for the discovery of novel inhibitors of JAK3

The JAKs protein family is composed of four isoforms, and JAK3 has been regarded as a druggable target for the development of drugs to treat various diseases, including hematologic tumors, cancer, and neuronal death. Therefore, the discovery of JAK3 inhibitors with novel scaffolds possesses the potential to provide additional options for drug development. This article presents a structure-based hybrid high-throughput virtual screening (HTVS) protocol as well as the DeepDock algorithm, which is based on geometric deep learning. These techniques were used to identify inhibitors of JAK3 with a novel sketch from a specific "In-house" database. Using molecular docking with varying precision, MM/GBSA, geometric deep learning scoring, and manual selection, 10 compounds were obtained for subsequent biological evaluation. One of these 10 compounds, compound 8, was found to have inhibitory potency against JAK3 and the MOLM-16 cell line, providing a valuable lead compound for further development of JAK3 inhibitors. To gain a better understanding of the interaction between compound 8 and JAK3, molecular dynamics (MD) simulations were conducted to provide more details on the binding conformation of compound 8 with JAK3 to guide the subsequent structure optimization. In this article, we achieved compound 8 with a novel sketch possessing inhibitory bioactivity against JAK3, and it would provide an acceptable "hit" for further structure optimization and modification to develop JAK3 inhibitors.

The current role of Tofacitinib in acute severe ulcerative colitis in adult patients: A systematic review

BACKGROUND

Despite rescue therapy, acute severe ulcerative colitis (ASUC) is associated with a high risk of colectomy, while treatment options remain limited. Tofacitinib, a rapidly acting Janus Kinase (JAK) inhibitor, is gaining ground as an effective alternative treatment option for the management of acute severe ulcerative colitis, which may prevent emergency colectomy.

METHODS

A systematic literature search of PubMed and Embase was undertaken for studies of adult patients with ASUC treated with tofacitinib.

RESULTS

In total, two observational studies, seven case series and five case reports incorporating 134 patients who received tofacitinib in ASUC were identified with a follow-up period ranging from 30 days to 14 months. Overall, the pooled colectomy rate was 23.9% (95% CI 16.6-31.2). The pooled 90-day and 6-month colectomy free rate were 79.9% (95% CI 73.1-86.7) and 71.6% (95% CI 64-79.2) respectively. The most frequent adverse event was C. Difficile infection.

CONCLUSIONS

Tofacitinib appears to be a promising option for the treatment of ASUC. Randomized clinical trials are required to further access the efficacy, safety and optimal dose of tofacitinib in cases of ASUC.