JAK2 Research Articles

Breakthrough Opportunities of Nanotheranostics in Psoriasis: From Pathogenesis to Management Strategy.

In this paper, we have discussed recent advances in our understanding of the aetiology of psoriasis, particularly as they relate to aryl hydrocarbon receptors in DCs, Langerhans cells, macrophages, signal transducer and activator of transcription 3 pathways, and dermal vascular endothelial cells. Here, we have shown that the ability to target specific cellular and molecular components of psoriasis pathogenesis with nanoscale precision using phos-phodiesterase 4 inhibitors represents a transformative opportunity to address the complex nature of this dermatological condition. In this review, we have examined the molecular mechanisms behind the pathogenic features of psoriasis and new treatments being tested in clinical settings. There is research being done on new treatments created in the last ten years. This field highlights the advantages of nan-otechnological technologies as cutting-edge candidates for drug delivery systems in psoriasis and other inflammatory chronic skin disorders. Future Developments: Nanotechnology-based treatments currently under study show good effi-cacy and low side effect profiles. However, long-term prospective trials are required to demon-strate long-term safety and effectiveness. Phosphodiesterase inhibitors, Janus kinase inhibitors, nonsteroidal anti-inflammatory drugs, combinations of vitamin D3 derivatives and corticoster-oids, and coal tar formulations are some of the newer topical treatments for psoriasis. The psoriasis treatment continues to involve conventional medications (i.e., medi-cines that are generally acknowledged as either normal therapy or outdated remedies), whether used topically or orally. Nonetheless, we are starting to see initiatives to create pharmaceuticals and biosimilars with better therapeutic results, fewer side effects, and greater efficacy.

Peperomia pellucida (L.) Kunth suppresses glycation-induced inflammatory response in human retinal pigment epithelial cell line ARPE-19 via JAK-STAT3 signaling.

The formation of advanced glycation end product (AGE) is a risk factor for diabetic retinopathy. Since the current treatment for diabetic retinopathy is accompanied by side effects, preliminary findings have suggested Peperomia pellucida (L.) Kunth as a potential alternative therapeutic option for diabetic retinopathy. This study aimed to elucidate the anti-inflammatory mechanism of P. pellucida in the AGE-stimulated human retinal pigment epithelial cell line ARPE-19. Phytochemical analysis revealed phenylpronanoids, terpenes, and fatty acids in P. pellucida. Through in vitro cell viability assay, the P. pellucida methanolic extract (IC50 = 8.70 mg/mL) and ethyl acetate fraction (IC50 = 7.34 mg/mL) were considered as non toxic for ARPE-19. AGE induced an inflammatory response in ARPE-19 by upregulating the gene (2.4-5.8-fold) and protein (1.4-2.3-fold) expression of signal transducer and activator of transcription 3 (STAT3), interleukin-8 (IL-8), monocyte chemoattractant protein-1, matrix metalloproteinase 2, and vascular endothelial growth factor. At 1.5 mg/mL, P. pellucida methanolic extract suppressed IL-8 expression (p < 0.05), implying its anti-inflammatory action at the early inflammatory stage through the Janus kinase (JAK)-STAT3 pathway. The methanolic extract also restored the ARPE-19 viability under AGE-induced inflammatory stress. The downregulation of inflammatory biomarkers along the JAK-STAT3 pathway suggested P. pellucida as a promising anti-inflammatory source for diabetic retinopathy.

Corneal application of SOCS1/3 peptides for the treatment of eye diseases mediated by inflammation and oxidative stress.

Several blinding diseases affecting the retina and optic nerve are exacerbated by or caused by dysregulated inflammation and oxidative stress. These diseases include uveitis, age related macular degeneration, diabetic retinopathy and glaucoma. Consequently, despite their divergent symptoms, treatments that reduce oxidative stress and suppress inflammation may be therapeutic. The production of inflammatory cytokines and their activities are regulated by a class of proteins termed Suppressors of Cytokine Signaling (SOCS). SOCS1 and SOCS3 are known to dampen signaling via pathways employing Janus kinases and signal transducer and activator of transcription proteins (JAK/STAT), Toll-like Receptors (TLR), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), mitogen activated kinase (MAPK) and NLR family pyrin domain containing 3 (NLRP3). We have developed cell-penetrating peptides from the kinase inhibitory region of the SOCS1 and SOCS3 (denoted as R9-SOCS1-KIR and R9-SOCS3-KIR) and tested them in retinal pigment epithelium (RPE) cells and in macrophage cell lines. SOCS-KIR peptides exhibited anti-inflammatory, anti-oxidant and anti-angiogenic properties. In cell culture, both Th1 and Th17 cells were suppressed together with the inhibition of other inflammatory markers. We also observed a decrease in oxidants and a simultaneous rise in neuroprotective and anti-oxidant effectors. In addition, treatment prevented the loss of gap junction proteins and the ensuing drop in transepithelial electrical resistance in RPE cells. When tested in mouse models by eye drop instillation, they showed protection against autoimmune uveitis, as a prophylactic as well as a therapeutic. Mice with endotoxin-induced uveitis were protected by eye drop administration as well. R9-SOCS3-KIR was particularly effective against the pathways acting through STAT3, e.g. IL-6 and VEGF-A mediated responses that lead to macular degeneration. Eye drop administration of R9-SOCS3-KIR stimulated production of antioxidant effectors and reduced clinical symptoms in mouse model of oxidative stress that replicates the RPE injury occurring in AMD. Because these peptides suppress multiple pathogenic stimuli and because they can be delivered topically to the cornea, they are attractive candidates for therapeutics for uveitis, macular degeneration, diabetic retinopathy and glaucoma.

Proinflammatory cytokines in rheumatoid arthritis: dynamics against therapy with Janus kinase and interleukin 6 inhibitors

Increased production of proinflammatory cytokines in serum and synovial fluid plays an important role in the pathogenesis of RA. JAK inhibitors and bDMARD are aimed at suppressing various pathological reactions caused by them.The aim of the study. To determine the effect of therapy with JAK and IL-6 inhibitors on the concentration of proinflammatory cytokines in RA patients in real clinical practice.Materials and methods. The study included 30 patients with a reliable diagnosis of RA, advanced stage of disease, with moderate or high RA activity and ineffectiveness of previous therapy with csDMARD or bDMARD for at least 6 months. 10 patients received TOFA at a dose of 5 mg twice daily 10 received UPA at a dose of 15 mg once daily and 10 were on OKZ therapy at a dose of 64 mg subcutaneously every 4 weeks. Studies were performed before treatment, after 3 and 6 months of therapy. The levels of IL-1β, IL-6, IL-17A, IL-17F, IL-23, IL-31, IL-33, INF-γ, TNF-α in serum were investigated using multiplex xMAR technology on Bio-PlexTM 200 System analyser (BIO-RAD, USA).Results. In all groups of patients after 3 and 6 months from the start of therapy, there was a significant decrease in the RA activity index compared to baseline values. The concentration of IL-1β, IL-17A, IL-17F and IL-23 did not change significantly during treatment with any of the drugs. IL-6 values on TOFA background significantly decreased after 3 and 6 months of follow-up compared to the baseline level. UPA therapy had no effect on IL-6 level during the whole observation period, and against the background of OKZ application its values significantly increased after 3 months, and after 6 months – decreased, remaining higher than the initial values. The concentration of IL-31 after 3 months of TOFA treatment significantly decreased (respectively: 6.95 (3.85; 17.72) pg/ml and 3.00 (1.50; 3.85) pg/ml, p&lt;0.05), and after 6 months – increased, but remained lower than baseline (5.09 (3.85; 6.33) pg/ml, p&lt;0.05). IL-33 level on the background of UPA decreased and after 6 months was significantly lower than baseline (1.11 (0.86; 3.95) pg/ ml; 1.05 (0.37; 3.95) and 0.37 (0.12; 1.23) pg/ml, p&lt;0.05). The concentration of INF-γ after 3 and 6 months of TOFA administration decreased significantly compared to the start of therapy (2.05 (1.48; 3.19) pg/ml; 0.99 (0.49; 2.05) pg/ml and 0.99 (0.49; 2.62) pg/ml, p&lt;0.05). Treatment with OKZ resulted in increased TNF-α levels after 6 months compared to baseline values of 0.79 (0.41; 0.98) pg/ml and 1.23 (0.67; 2.06) pg/ml, p&lt;0.05.Conclusions. The use of TOFA, UPA and OKZ in RA patients has a positive effect on disease activity, but has different effects on the level of proinflammatory cytokines in serum.

The Association Between Deep Vein Thrombosis, Pulmonary Embolism, and Janus Kinase Inhibitors: Reporting Status and Signal Detection in the Japanese Adverse Drug Event Report Database.

Although Janus kinase (JAK) inhibitors have expanding indications, deep vein thrombosis (DVT) and pulmonary embolism (PE) are serious adverse events associated with their use. Moreover, their analysis using the Japanese database of spontaneous adverse drug reaction reports has not yet been conducted. The objective of this study was to analyze the Japanese Adverse Drug Event Report database (JADER) to evaluate the association between JAK inhibitors and DVT and PE. JADER reports from April 2004 to October 2023 were analyzed. A classification of reports for the period covered was performed by drug, and an imbalance analysis was performed with oral JAK inhibitors as the target drug and DVT, PE, and "embolic and thrombotic events, venous" (Standardised MedDRA Query; SMQ) as the target adverse events. Reported odds ratios (ROR) and information components (IC) were calculated for signal detection. Overall, 6631 JAK inhibitor-related adverse events were reported, including 60 and 41 cases of DVT and PE, respectively. The ROR and IC of the JAK inhibitors for DVT were 2.52 (1.95-3.25) and 1.27 (0.41-2.13), while those of baricitinib for DVT were 4.37 (2.83-6.73) and 1.90 (0.47-3.33), respectively. ROR signals were detected for JAK inhibitors for PE and "embolic and thrombotic events, venous (SMQ)," overall and for several JAK inhibitors but none for IC. Several JAK inhibitors are under postmarketing phase vigilance, and the number of reported adverse events is low. However, when administering these drugs, care should be taken to avoid the development of thromboembolism, considering the patient's background.

Re-evaluating Methods for Assessing Differences in Response in Ileal vs. Colonic Crohn's Disease: A Post-hoc Analysis of the FITZROY Trial.

The ileum is the most commonly affected segment of the gastrointestinal tract in Crohn's disease (CD). We aimed to determine whether disease location affects response to filgotinib, a Janus kinase (JAK) inhibitor, in patients with moderate-to-severely active Crohn's disease (CD) and applying appropriate methods to account for differences in measuring disease activity in the ileum compared to the colon. This post-hoc analysis of data from the FITZROY phase 2 trial (NCT02048618) compared changes in the Crohn's Disease Activity Index (CDAI) and Simple Endoscopic Score for Crohn's Disease (SES-CD) amongst patients with ileal-dominant and isolated colonic CD treated with 10 weeks of filgotinib 200mg daily or placebo. A mixed effects model for repeated measures was used to test whether ileal disease responded differently than colonic disease, by evaluating for effect modification using the interaction term of treatment assignment-by-disease location. Numerically greater proportions of patients with isolated colonic disease compared to ileal-dominant CD achieved clinical remission (CDAI <150, 75.9% vs. 41.6%) and endoscopic response (SES-CD reduction by 50%, 52.5% vs. 15.5%) at Week 10. However, after adjusting for baseline disease activity by disease location and within-patient clustering effects, there was no significant difference in treatment response by disease location (mean difference in ΔCDAI between ileal-dominant vs. isolated colonic disease +9.24 [95% CI: -87.19, +105.67], p=0.85; mean difference in ΔSES-CD -1.93 [95% CI: -7.03, +3.44], p=0.48). Filgotinib demonstrated similar efficacy in ileal-dominant and isolated colonic CD when controlling for baseline disease activity and clustering effects.

Daphnetin alleviates allergic airway inflammation by inhibiting T-cell activation and subsequent JAK/STAT6 signaling

Allergic asthma is a major health burden on society as a chronic respiratory disease characterized by inflammation and muscle tightening around the airways in response to inhaled allergens. Daphne kiusiana Miquel is a medicinal plant that can suppress allergic airway inflammation; however, its specific molecular mechanisms of action are unclear. In this study, we aimed to elucidate the mechanisms by which D. kiusiana inhibits allergic airway inflammation. We evaluated the anti-inflammatory effects of the ethyl acetate (EA) fraction of D. kiusiana and its major compound, daphnetin, on murine T lymphocyte EL4 cells stimulated with phorbol 12-myristate 13-acetate and ionomycin in vitro and on asthmatic mice stimulated with ovalbumin in vivo. The EA fraction and daphnetin inhibited T-helper type 2 (Th2) cytokine secretion, serum immunoglobulin E production, mucus secretion, and inflammatory cell recruitment in vivo. In vitro, daphnetin suppressed intracellular Ca2+ mobilization (a critical regulator of nuclear factor of activated T cells) and functions of the activator protein 1 transcription factor to reduce interleukin (IL)-4 and IL-13 expression. Daphnetin effectively suppressed the IL-4/-13-induced activation of Janus kinase (JAK)/signal transducer and activator of transcription 6 (STAT6) signaling in vitro and in vivo, thereby inhibiting the expression of GATA3 and PDEF, two STAT6-target genes responsible for producing Th2 cytokines and mucins. These findings indicate that daphnetin suppresses allergic airway inflammation by stabilizing intracellular Ca2+ levels and subsequently inactivating the JAK/STAT6/GATA3/PDEF pathway, suggesting that daphnetin is a promising alternative to existing asthma treatments.

Review of modern methods of treating vitiligo

Vitiligo is an autoimmune disease that causes skin depigmentation. The article is a review of the literature with a detailed description of the pathogenesis and the main combinations of therapeutic approaches. The issue of the use of oral and topical janus kinase inhibitors for the treatment of vitiligo was raised.

Successful treatment of infantile refractory bullous pemphigoid with baricitinib.

Infantile bullous pemphigoid (BP) is a rare autoantibody-mediated skin disorder. We report the effective treatment of a 6-month-old infant with BP using baricitinib, a Janus kinase (JAK) inhibitor, after failure with steroids and intravenous immunoglobulin. The patient achieved full remission and discontinued all medications without any relapses. To our knowledge, this is the first case of baricitinib used in an infant with BP.

Associations of CYLD, JAK2 and TLR4 Genotypes with PSA Levels and Immunophenotype in Benign Prostatic Hyperplasia and Prostate Cancer.

Prostate cancer (PCa) is one of the most common malignant tumors of the male urinary system, and its incidence and mortality rates have been increasing worldwide. Benign prostatic hyperplasia (BPH) represents stromal and epithelial cell proliferation in the prostate in elderly males. Abnormal activation of inflammation-related signalling molecules, such as toll-like receptor 4 (TLR4) and Janus kinase/signal transducers and activators of transcription (JAK/STAT) has been linked to the initiation and progression of various human diseases including PCa and BPH. Cylindromatosis (CYLD) gene alterations are associated with PCa progression. In this study, the contribution of CYLD, JAK2, and TLR4 gene variants to PCa and BPH risks and their associations with prostate-specific antigen (PSA) levels, immunophenotype, and clinical features in Vietnamese men were determined. A total of 102 patients with PCa, 65 with BPH, and 114 healthy controls were enrolled. The immunophenotype was analyzed by flow cytometry, cytokine secretion by enzyme-linked immunosorbent assay (ELISA), and gene variants by DNA sequencing. Lower levels of transforming growth factor β (TGF-β) and higher numbers of CD13+CD117- and CD56+CD25+ cells were observed in the PCa group than in the BPH group. Genetic analysis of the CYLD gene identified five single nucleotide polymorphisms (SNPs), of which c.2351-47 C>T, c.2351-46A>T, and rs1971432171 T>G had significantly higher frequencies in PCa patients than in the control and BPH groups. Sequencing of the TLR4 gene revealed five nucleotide changes, in which the rs2149356 SNP showed an increased risk for both PCa and BPH and the c.331-206 SNP had a reduced risk for PCa. Importantly, the expansion of activated natural killer (NK) cells and higher levels of PSA were found in PCa patients carrying the CT genotype of the CYLD c.2351-47 compared to those with the wild-type genotype. Activation of NK cells in CYLD-sensitive PCa patients was associated with serum PSA release and the CYLD c.2351-47 variant may be a significant risk factor for prostatitis in PCa patients.

Filgotinib in Active Noninfectious Uveitis

Noninfectious uveitis is a leading cause of visual impairment with an unmet need for additional treatment options. To assess the efficacy and safety of filgotinib, a Janus kinase 1 (JAK1) preferential inhibitor, for the treatment of noninfectious uveitis. The HUMBOLDT trial was a double-masked, placebo-controlled, phase 2, randomized clinical trial conducted from July 2017 to April 2021 at 26 centers in 7 countries. Eligible participants (aged ≥18 years) had active noninfectious intermediate uveitis, posterior uveitis, or panuveitis despite at least 2 weeks of treatment with oral prednisone (10-60 mg per day). Participants were randomly assigned 1:1 to receive filgotinib, 200 mg, or placebo orally once daily for up to 52 weeks. The primary end point was the proportion of participants experiencing treatment failure by week 24. Treatment failure was a composite end point represented by assessment of the presence of chorioretinal and/or retinal vascular lesions, best-corrected visual acuity, and anterior chamber cell and vitreous haze grades. Safety was assessed in participants who received at least 1 dose of study drug or placebo. Between July 26, 2017, and April 22, 2021, 116 participants were screened, and 74 (mean [SD] age, 46 [16] years; 43 female [59.7%] of 72 participants, as 2 participants did not receive treatment doses) were randomly assigned to receive filgotinib (n = 38) or placebo (n = 36). Despite early termination of the trial for business reasons ahead of meeting enrollment targets, a significantly reduced proportion of participants who received filgotinib experienced treatment failure by week 24 vs placebo (12 of 32 participants [37.5%] vs 23 of 34 participants [67.6%]; difference vs placebo -30.1%; 95% CI, -56.2% to -4.1%; P = .006). Business reasons were unrelated to efficacy or safety. Adverse events were reported in 30 of 37 participants (81.1%) who received filgotinib and in 24 of 35 participants (68.6%) who received placebo. Serious adverse events were reported in 5 of 37 participants (13.5%) in the filgotinib group and in 2 of 35 participants (5.7%) in the placebo group. No deaths were reported during the trial. Results of this randomized clinical trial show that filgotinib lowered the risk of treatment failure in participants with active noninfectious intermediate uveitis, posterior uveitis, or panuveitis vs placebo. Although the HUMBOLDT trial provided evidence supporting the efficacy of filgotinib in patients with active noninfectious uveitis, the premature termination of the trial prevented collection of additional safety or efficacy information of this JAK1 preferential inhibitor. ClinicalTrials.gov Identifier: NCT03207815.

Maternal administration of APAP induces angiogenesis disorders in mouse placenta via SOCS3/JAK1/STAT3 pathway

Acetaminophen (APAP, also known as paracetamol) is a commonly used antipyretic and analgesic that is considered safe to use during pregnancy. However, a growing body of research indicates that gestational administration of APAP increased the risk of neurodevelopmental, reproductive and genitourinary disorders in offspring, alongside impairments in placental development. Notably, over-dosed APAP exhibits direct toxicity to endothelial cells, but there is very limited research investigating the impact of APAP on placental angiogenesis, a gap we aim to address in this study. Pregnant mice were gavaged with APAP (15, 50 and 150 mg/kg/d) from embryonic day 11.5 (E11.5) to E13.5. Administration of 150 mg/kg/d APAP leads to low birth weight (LBW) of the offspring and disordered vascular structures within the labyrinthine (Lab) layer of the placenta. This disruption is accompanied by a significant increase in Suppressor of Cytokine Signaling 3 (SOCS3) level, a negative regulator of the Janus kinase signal transducer 1 and activator of the transcription 3 (JAK1/STAT3) signaling. Meanwhile, Human umbilical vein endothelial Cells (HUVECs) with the treatment of 3 mM APAP exhibited reduced cell viability, whereas 1 mM APAP significantly affected the proliferation, migration, invasion and angiogenic capacities of HUVECs. Further, SOCS3 was up-regulated in HUVECs, accompanied by inhibition of JAK1/STAT3 pathways. Knocking-down SOCS3 in HUVECs restored the nuclear translocation of STAT3 and efficiently promoted cellular capacity of tube formation. Overall, short-term maternal administration of overdosed APAP impairs angiogenic capacities of fetal endothelial cells via SOCS3/JAK1/STAT3 pathway in the mouse placenta. This study reveals that overdose of APAP during pregnancy may adversely affect placental angiogenesis, emphasizing the importance of adhering to the safe principles of smallest effective dose for the shortest required durations.

STAT4 Mediates IL-6 Trans-Signaling Arrhythmias in High Fat Diet Guinea Pig Heart.

Obesity is a major risk factor for the development of life-threatening malignant ventricular tachyarrhythmias (VT) and sudden cardiac death (SCD). Risks may be highest for patients with high levels of the proinflammatory cytokine interleukin (IL)-6. We used our guinea pig model of high-fat diet (HFD)-induced arrhythmias that exhibit a heightened proinflammatory-like pathology, which is also observed in human obesity arrhythmias, as well as immunofluorescence and confocal microscopy approaches to evaluate the pathological IL-6 trans-signaling function and explore the underlying mechanisms. Using blind-stick and electrocardiogram (ECG) techniques, we tested the hypothesis that heightened IL-6 trans-signaling would exhibit increased ventricular arrhythmia/SCD incidence and underlying arrhythmia substrates. Remarkably, compared to low-fat diet (LFD)-fed controls, HFD promoted phosphorylation of the IL-6 signal transducer and activator of transcription 4 (STAT4), leading to its activation and enhanced nuclear translocation of pSTAT4/STAT4 compared to LFD controls and pSTAT3/STAT3 nuclear expression. Overactivation of IL-6 trans-signaling in guinea pigs prolonged the QT interval, which resulted in greater susceptibility to arrhythmias/SCD with isoproterenol challenge, as also observed with the downstream Janus kinase (JAK) 2 activator. These findings may have potentially profound implications for more effective arrhythmia therapy in the vulnerable obese patient population.

Optical genome mapping improves the accuracy of classification, risk stratification, and personalized treatment strategies for patients with acute myeloid leukemia.

Cytogenomic characterization is crucial for the classification and risk stratification of acute myeloid leukemia (AML), thereby facilitating therapeutic decision-making. We examined the clinical utility of optical genome mapping (OGM) in 159 AML patients (103 newly diagnosed and 56 refractory/relapsed), all of whom also underwent chromosomal banding analysis (CBA), fluorescence in situ hybridization, and targeted next-generation sequencing. OGM detected nearly all clinically relevant cytogenetic abnormalities that SCG identified with >99% sensitivity, provided the clonal burden was above 20%. OGM identified additional cytogenomic aberrations and/or provided information on fusion genes in 77 (48%) patients, including eight patients with normal karyotypes and four with failed karyotyping. The most common additional alterations identified by OGM included chromoanagenesis (n = 23), KMT2A partial tandem duplication (n = 11), rearrangements involving MECOM (n = 7), NUP98 (n = 2), KMT2A (n = 2), JAK2 (n = 2), and other gene fusions in 17 patients, with 10 showing novel fusion gene partners. OGM also pinpointed fusion genes in 17 (11%) patients where chromosomal rearrangements were concurrently detected by OGM and CBA. Overall, 24 (15%) aberrations were identified exclusively by OGM and had the potential to alter AML classification, risk stratification, and/or clinical trial eligibility. OGM emerges as a powerful tool for identifying fusion genes and detecting subtle or cryptic cytogenomic aberrations that may otherwise remain undetectable by CBA.

JAK inhibitors attenuate hyperactivation of nonswitched memory B cells in rheumatoid arthritis patients in remission

ObjectiveTo investigate the distribution and activation of B-cell subpopulations in rheumatoid arthritis (RA) patients treated with Janus kinase inhibitors (JAKis) and to analyze their correlation with disease remission.MethodsPeripheral blood samples were collected from 23 adult healthy controls and 58 RA patients, 31 of whom were treated with JAKis and assessed during a 24-month follow-up. The number of peripheral B-cell subpopulations (including naive B cells, nonswitched memory B (NSMB) cells, switched memory B cells, and double-negative B cells), their activation, and phosphorylation of SYK and AKT upon B-cell receptor (BCR) stimulation in each population were analyzed by flow cytometry.ResultsCompared with that in healthy controls, the frequency of NSMB cells was significantly lower in new-onset untreated RA patients. However, expression of CD40, CD80, CD95, CD21low and pAKT significantly increased in these NSMB cells. Additionally, the number of NSMB cells correlated negatively with DAS28-ESR and IgG and IgA levels in these patients; expression of CD80, CD95 and CD21low on NSMB cells correlated positively with DAS28-ESR and IgG and IgA levels. After treatment with JAKis, the serum IgG concentration significantly decreased in RA patients in remission, but CD40, CD95 and pAKT levels in NSMB cells significantly decreased.ConclusionRA patients present different B-cell subpopulations, in which the frequency of NSMB cells is negatively associated with disease activity. However, treatment with JAKis can inhibit activation of NSMB cells, restore the balance of kinase phosphorylation, and facilitate disease remission in RA patients.

Evolution of dupilumab-associated conjunctivitis in patients with atopic dermatitis after switching dupilumab to tralokinumab or Janus kinase inhibitors (RESO-ADOC study).

Clinical trials and real-life data have reported an increased incidence of conjunctivitis in patients treated with dupilumab for their atopic dermatitis (AD). Although mostly mild in severity, in some cases conjunctivitis will appear or increase after dupilumab initiation, which can lead to dupilumab discontinuation. (1) To describe the characteristics of patients developing conjunctivitis requiring discontinuation of dupilumab; and (2) to analyse the factors associated with a complete conjunctivitis improvement after dupilumab discontinuation and a switch to tralokinumab or Janus kinase inhibitors. This was a multicentre retrospective cohort study that included all patients with AD treated with dupilumab who developed conjunctivitis leading to dupilumab discontinuation and switching to tralokinumab or Janus kinase inhibitors in daily practice. Data on patients, their AD and conjunctivitis were analysed at the inclusion visit (corresponding to discontinuation of dupilumab and the institution of new AD treatment), at visit 2 (3-6 months after inclusion) and at visit 3 (corresponding to the last medical visit). After multivariate analysis, the only factors associated with a complete resolution of dupilumab-associated conjunctivitis at visit 2 and/or visit 3 were conjunctivitis duration (OR 8.98, 95% CI 1.47-55) (p = 0.018), personal history of asthma (OR 10.66, 95% CI 1.82-62.63) (p = 0.009) and switching from dupilumab to Janus kinase inhibitors (OR 17.11, 95% CI 2.94-99.66) (p = 0.002). Although uncommon, severe dupilumab-associated conjunctivitis is more frequent in daily life compared to its incidence in the dupilumab pivotal trials. In these cases, our study suggests that a rapid switch to another molecule, particularly a Janus kinase inhibitor, should be considered.

Structural basis of MPL activation by thrombopoietin

AbstractMyeloproliferative leukemia protein (MPL), also known as thrombopoietin (TPO) receptor, is a class I cytokine receptor that is expressed on hematopoietic progenitors, promoting growth and differentiation toward the megakaryocyte lineage and is critical for normal platelet production. Mutations in MPL, TPO, or Janus kinase 2 (JAK2) have been implicated in multiple diseases from congenital thrombocytopenias to myeloproliferative neoplasms. The ligand for MPL, TPO, stimulates platelet production by inducing MPL dimerization and results in an active conformation that allows downstream JAK2/STAT5 signaling. Despite the biological importance of this pathway, the molecular signaling mechanism remained unclear. Here, we present a 3.39-Å cryo-electron microscopy structure of the ectodomain of mouse MPL bound to TPO. The structure revealed both low and high affinity sites between MPL and TPO that contain several pathologic mutations. To better understand TPO-driven MPL signaling, we expanded upon this structure by molecular dynamic (MD) simulations to model the full-length human MPL/TPO complex, and showed that MPL D4-D4 domain interactions are functionally relevant in activity assays. To build on our understanding of downstream activation, we added JAK2 to the MPL/TPO complex by MD simulations. This ternary complex illustrates JAK2 dimerization through the pseudokinase domain, illustrates residues important for MPL interactions, and reveals the constitutive activation mechanism of patient mutant V617F. The model also suggests the mechanism of JAK2 tyrosine kinase domain transphosphorylation. Overall, our studies illuminate TPO/MPL/JAK2 signaling mechanisms and provide additional insight into the nature of receptor signaling, which will further benefit human health.

Regulation of STAT5 phosphorylation and interaction with SHP1 by lnc-AC004893, a long non-coding RNA overexpressed in myeloproliferative neoplasms

ABSTRACT Objectives Constitutive activation of Janus kinase 2 (JAK2)/signal transducer and activator of transcription (STAT) signaling pathway is central to the pathogenesis of myeloproliferative neoplasms (MPNs). Long noncoding RNAs (lncRNAs) regulate diverse biological processes. However, the role of lncRNAs in MPN pathogenesis is not well studied. Methods The expression of lnc-AC004893 in MPN patients was measured by quantitative real-time PCR (qRT-PCR). Gene-specific short hairpin RNAs (shRNAs) were designed to inhibit the expression of lnc-AC004893, and western blot was performed to explore the role of lnc-AC004893 via regulating the JAK2/STAT5 signaling pathway. Furthermore, co-IP was performed to determine the binding ability of lnc-AC004893 and STAT5 protein. Finally, the BaF3-JAK2V617F-transplanted mouse model was used to assess the biological role of lnc-ac004893 in vivo. Results We report that lnc-AC004893, a poorly conserved pseudogene-209, is substantially upregulated in MPN cells compared with normal controls (NCs). Knockdown of lnc-AC004893 by specific shRNAs suppressed cell proliferation and decreased colony formation. Furthermore, the knockdown of lnc-AC004893 reduced the expression of p-STAT5 but not total STAT5 in HEL and murine IL-3-dependent Ba/F3 cells, which present constitutive and inducible activation of JAK2/STAT5 signaling. In addition, inhibition of murine lnc-ac004893 attenuated BaF3-JAK2V617F-transplanted phenotypes and extended the overall survival. Mechanistically, knockdown of lnc-AC004893 enhanced the binding ability of STAT5 and protein tyrosine phosphatase SHP1. Furthermore, knockdown of lnc-AC004893 decreased STAT5-lnc-AC004893 interaction but not SHP1-lnc-AC004893 interaction. Conclusion Lnc-AC004893 regulates STAT5 phosphorylation by affecting the interaction of STAT5 and SHP1. Lnc-AC004893 might be a potential therapeutic target for MPN patients.

Oncostatin M promotes osteogenic differentiation of tendon-derived stem cells through the JAK2/STAT3 signalling pathway

PurposeOncostatin M (OSM) is involved in the regulation of osteogenic differentiation and has a major role in the development of heterotopic ossification. The role of OSM in osteogenic differentiation of tendon-derived stem cells (TDSCs) and its mechanism have not been reported. This study aim to investigate the role of OSM in osteogenic differentiation of TDSCs and study the mechanism.MethodsTDSCs were differentiated in osteogenic differentiation medium for 7 days. Recombinant OSM was added to the osteogenic differentiation medium for 7 and 14 days. The effect of Janus kinase 2 (JAK2) inhibitor AZD1480 and signal transducer and activator of transcription 3 (STAT3) inhibitor stattic in the presence of recombinant OSM on osteogenic differentiation of TDSCs was examined after differentiation for 7 and 14 days. Alkaline phosphatase and alizarin red staining were used to assess the effects on early and mid-stage osteogenic differentiation, respectively. Western blotting and qPCR were used to assess the expression of receptor and signalling pathway-related proteins and osteogenic marker genes, respectively.ResultsTDSCs were successfully induced to differentiate into osteoblasts. Recombinant OSM promoted osteogenic differentiation of TDSCs to early and mid-stages. After addition of AZD1480 or stattic, decreased alkaline phosphatase and alizarin red staining were observed in the early and mid-stages of osteogenic differentiation. Additionally, decreased expression of receptor and pathway-related proteins, and osteogenic genes was found by western blotting and qPCR, respectively.ConclusionOSM promotes osteogenic differentiation of TDSCs and the JAK2/STAT3 signalling pathway plays an important role.

Biologics Versus JAK Inhibitors. Part II: Risk of Infections. A Narrative Review.

The risk of infections associated with biological drugs (BD) and Janus kinase inhibitors (JAKi) has been extensively explored in the literature. However, there is a dearth of studies that evaluate both pharmacological groups together and, furthermore, compare them. Here, we review the risk of infections associated with BD and JAKi used in dermatology. A narrative review was performed. All relevant articles evaluating the risk of infection and opportunistic infections with BD and JAKi between January 2010 and February 2024 were selected. Overall, the incidence of infections, serious infections, and opportunistic infections associated with BD and JAKi is low, but higher than in the general population. JAKi approved for dermatological disorders (abrocitinib, baricitinib, deucravacitinib, upadacitinib, ritlecitinib, and topical ruxolitinib) have been shown to be safe, and present a low rate of infections. We found an elevated risk, especially with anti-tumor necrosis factor (anti-TNF) agents, rituximab, and JAKi (particularly tofacitinib at high doses). Specific associations with infections include tuberculosis and tuberculosis reactivation with anti-TNF agents and tocilizumab; candidiasis with anti-interleukin (IL) 17 agents; hepatitisB virus reactivation with rituximab, anti-TNF, and JAKi; and herpes simplex and herpes zoster infections with JAKi (especially tofacitinib and upadacitinib at high doses). The incidence of infections with ustekinumab and anti-IL-23 was very low. Anti-IL-1, nemolizumab, tralokinumab, and omalizumab were not associated with an increased risk of infections. Dupilumab could decrease the incidence of cutaneous infections. Anti-TNF agents, rituximab, and JAKi (particularly tofacitinib) can increase the risk of infections. Close monitoring of patients undergoing these therapies is recommended. Prospective studies with long-term follow-up are needed to comparatively evaluate the risks of infection deriving from treatment with BD and JAKi.