The treatment of Tofacitinib for rosacea through the inhibition of the JAK/STAT signaling pathway.

Rosacea is a chronic inflammatory skin disease characterized by facial erythema and telangiectasia. Despite ongoing research, the pathogenesis of rosacea remains incompletely understood, and current therapies are not entirely satisfactory. The JAK/STAT signaling pathway plays an essential role in immunoregulation, inflammation, and neurovascular regulation. Inhibition of the JAK/STAT pathway appears to hold promise as a potential therapy for rosacea. This study aimed to investigate the effects of the JAK inhibitor tofacitinib on rosacea and to preliminarily explore its therapeutic mechanism. To this end, a rosacea-like mouse model was induced using LL37 and treated with a 2% tofacitinib emulsion. The results demonstrated that topical application of tofacitinib significantly ameliorated rosacea-like phenotype, reduced the infiltration of CD4+ T cells and mast cells, and suppressed dermal angiogenesis. RT-qPCR analysis revealed a reduction in mRNA expression levels of STAT1, STAT4, and STAT5a in skin lesions following topical tofacitinib treatment. Additionally, three patients diagnosed with erythematotelangiectatic rosacea (ETR) were included in the study and treated with oral tofacitinib, leading to a significant improvement in erythema and flushing symptoms. These findings collectively suggest that tofacitinib alleviates LL37-induced rosacea-like skin inflammation in mice and rosacea skin lesions by inhibiting the JAK/STAT signaling pathway.

Sun R ，Fan H ，Liu J ，Gao G ，Liu C ，Zhang D ，Ma W ... -  《-》

Tofacitinib Suppresses Several JAK-STAT Pathways in Rheumatoid Arthritis In Vivo and Baseline Signaling Profile Associates With Treatment Response.

Current knowledge on the actions of tofacitinib on cytokine signaling pathways in rheumatoid arthritis (RA) is based on in vitro studies. Our study is the first to examine the effects of tofacitinib treatment on Janus kinase (JAK) - signal transducer and activator of transcription (STAT) pathways in vivo in patients with RA. Sixteen patients with active RA, despite treatment with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs), received tofacitinib 5 mg twice daily for three months. Levels of constitutive and cytokine-induced phosphorylated STATs in peripheral blood monocytes, T cells and B cells were measured by flow cytometry at baseline and three-month visits. mRNA expression of JAKs, STATs and suppressors of cytokine signaling (SOCS) were measured from peripheral blood mononuclear cells (PBMCs) by quantitative PCR. Association of baseline signaling profile with treatment response was also investigated. Tofacitinib, in csDMARDs background, decreased median disease activity score (DAS28) from 4.4 to 2.6 (p < 0.001). Tofacitinib treatment significantly decreased cytokine-induced phosphorylation of all JAK-STAT pathways studied. However, the magnitude of the inhibitory effect depended on the cytokine and cell type studied, varying from 10% to 73% inhibition following 3-month treatment with tofacitinib. In general, strongest inhibition by tofacitinib was observed with STAT phosphorylations induced by cytokines signaling through the common-γ-chain cytokine receptor in T cells, while lowest inhibition was demonstrated for IL-10 -induced STAT3 phosphorylation in monocytes. Constitutive STAT1, STAT3, STAT4 and STAT5 phosphorylation in monocytes and/or T cells was also downregulated by tofacitinib. Tofacitinib treatment downregulated the expression of several JAK-STAT pathway components in PBMCs, SOCSs showing the strongest downregulation. Baseline STAT phosphorylation levels in T cells and monocytes and SOCS3 expression in PBMCs correlated with treatment response. Tofacitinib suppresses multiple JAK-STAT pathways in cytokine and cell population specific manner in RA patients in vivo. Besides directly inhibiting JAK activation, tofacitinib downregulates the expression of JAK-STAT pathway components. This may modulate the effects of tofacitinib on JAK-STAT pathway activation in vivo and explain some of the differential findings between the current study and previous in vitro studies. Finally, baseline immunological markers associate with the treatment response to tofacitinib.

Palmroth M ，Kuuliala K ，Peltomaa R ，Virtanen A ，Kuuliala A ，Kurttila A ，Kinnunen A ，Leirisalo-Repo M ，Silvennoinen O ，Isomäki P ... -  《Frontiers in Immunology》

Inhibition of JAK-STAT Signaling Suppresses Pathogenic Immune Responses in Medium and Large Vessel Vasculitis.

Giant cell arteritis, a chronic autoimmune disease of the aorta and its large branches, is complicated by aneurysm formation, dissection, and arterial occlusions. Arterial wall dendritic cells attract CD4+ T cells and macrophages to form prototypic granulomatous infiltrates. Vasculitic lesions contain a diverse array of effector T cells that persist despite corticosteroid therapy and sustain chronic, smoldering vasculitis. Transmural inflammation induces microvascular neoangiogenesis and results in lumen-occlusive intimal hyperplasia. We have examined whether persistent vessel wall inflammation is maintained by lesional T cells, including the newly identified tissue-resident memory T cells, and whether such T cells are sensitive to the cytokine-signaling inhibitor tofacitinib, a Janus kinase (JAK) inhibitor targeting JAK3 and JAK1. Vascular inflammation was induced in human arteries engrafted into immunodeficient mice that were reconstituted with T cells and monocytes from patients with giant cell arteritis. Mice carrying inflamed human arteries were treated with tofacitinib or vehicle. Vasculitic arteries were examined for gene expression (reverse transcription polymerase chain reaction), protein expression (immunohistochemistry), and infiltrating cell populations (flow cytometry). Tofacitinib effectively suppressed innate and adaptive immunity in the vessel wall. Lesional T cells responded to tofacitinib with reduced proliferation rates (<10%) and minimal production of the effector molecules interferon-γ, interleukin-17, and interleukin-21. Tofacitinib disrupted adventitial microvascular angiogenesis, reduced outgrowth of hyperplastic intima, and minimized CD4+CD103+ tissue-resident memory T cells. Cytokine signaling dependent on JAK3 and JAK1 is critically important in chronic inflammation of medium and large arteries. The JAK inhibitor tofacitinib effectively suppresses tissue-resident memory T cells and inhibits core vasculitogenic effector pathways.

Zhang H ，Watanabe R ，Berry GJ ，Tian L ，Goronzy JJ ，Weyand CM ... -  《-》

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

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

Calbet M ，Ramis I ，Calama E ，Carreño C ，Paris S ，Maldonado M ，Orellana A ，Calaf E ，Pauta M ，De Alba J ，Bach J ，Miralpeix M ... -  《-》

Sitagliptin and tofacitinib ameliorate adjuvant induced arthritis via modulating the cross talk between JAK/STAT and TLR-4/NF-κB signaling pathways.

Rheumatoid arthritis is an autoimmune systemic disorder causing pain, swelling, stiffness, and disability in various joints. This work was designed to evaluate the effect of sitagliptin and tofacitinib on Janus kinase (JAK)/signaling transducer and activator of transcription (STAT) and toll like receptor (TLR-4)/nuclear factor kappa B (NF-κB) signaling pathways in adjuvant induced arthritis in rats. Severity of arthritis was evaluated and serum was analyzed for inflammatory mediators. The mRNA and protein expression level of the most important members of the two signaling pathways were determined. Lipid profile, transaminases and renal function parameters were assessed. Sitagliptin and tofacitinib significantly decreased the level of inflammatory parameters, the mRNA and protein expression level of the members of JAK/STAT and TLR-4/NF-κB pathways with more prominent effect of sitagliptin on TLR-4/NF-κB pathway and more expected obvious effect of tofacitinib on JAK/STAT pathway. The combination offered additional anti-inflammatory effect by inhibiting the cross talk between these pathways as inhibition of NF-κB activation decreased the serum level of IL-6 preventing the activation of STAT-3 in tibiotarsal tissues. The combination of tofacitinib and sitagliptin normalized serum lipids and blood glucose level which could offer protection against cardiovascular diseases and caused partial reversal of serum transaminases and creatinine levels which can protect against tofacitinb's related hepato and nephrotoxicity. We could conclude that the combination of Sitagliptin with tofacitinib can offer synergistic anti-inflammatory effect and more protective action against side effects of tofacitinib.

Ibrahim SSA ，Salama MA ，Selima E ，Shehata RR ... -  《-》