The role of Janus kinase signaling in the pathology of atopic dermatitis

Predictive factors for treatment responses to baricitinib in severe alopecia areata: A retrospective, multivariate analysis of 70 cases from a single center

Alopecia areata (AA) is a chronic, autoimmune skin disease characterized by non-scarring hair loss. Baricitinib, a Janus kinase inhibitor (JAKi), prevents hair loss and promotes hair regrowth by inhibiting the inflammatory Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathway involved in cytotoxic T cell responses targeting hair follicles. The introduction of JAKi has transformed treatment against severe AA. However, treatment responses to JAKi are highly variable among patients, and the predictors of responsiveness remain insufficiently elucidated. This study aimed to identify independent predictive factors for the efficacy of baricitinib in patients with severe AA using multivariate analyses. A retrospective study was conducted on 70 severe AA patients who started baricitinib treatment at Tohoku University Hospital between July 2022 and August 2023. The primary outcome was the percentage of patients achieving a Severity of Alopecia Tool (SALT) score of ≤20 after 9 months of baricitinib treatment. Multivariate analysis assessed potential predictors of baricitinib treatment responses, including AA type, sex, age, disease duration, history of atopic dermatitis, intravenous methylprednisolone pulse (IVMP) therapy, and Clinician-Reported Outcome (ClinRO) measures for eyebrows and eyelashes. Achievement of a SALT score of ≤20 and SALT score improvement rates were used as objective variables in the multivariate analyses. Among the 70 patients completing 9 months of baricitinib treatment, 41% achieved a SALT score of ≤20. Multivariate analyses identified several independent predictors for positive outcomes, including shorter disease duration (≤4 years), history of IVMP, therapy SALT score of ≤95 at baricitinib initiation, and female sex. Further, we found differential response patterns based on AA type and sex. Specifically, AA type significantly influenced treatment responses, with ophiasis alopecia (OA) associated with the poorest improvement rate. In summary, the response to baricitinib in AA is significantly influenced by sex, AA type, disease duration, history of IVMP, and pre-treatment SALT score.

Inborn errors of immunity with atopic phenotypes in the allergy and immunology clinic: a practical review

PURPOSE OF REVIEW

Inborn errors of immunity with atopic phenotypes (IEIwA) are a subgroup of IEI that may present with severe and/or multiple atopic clinical manifestations. Because of their specific clinical management and prognosis, it is important to distinguish IEIwA from multifactorial allergic diseases. We aimed to review the main clinical manifestations associated with IEIwA and summarize the available data regarding the precision medicine approach for these conditions.

RECENT FINDINGS

IEIwA include more than 50 monogenic disorders marked by different immune dysregulation mechanisms such as alterations in cytokine signaling, T cell receptor function, mast cell activation, and skin barrier integrity. A critical role in diagnosis is played by advanced genetic testing. Emerging treatments include targeted monoclonal antibodies and small molecules, whereas hematopoietic stem cell transplantation (HSCT) is still a valid option for some specific disorders and may be curative also on atopic manifestations.

SUMMARY

The recognition and accurate diagnosis of IEIwA are crucial for timely and appropriate therapeutic intervention. The diagnosis should be suspected according to the presence of 'red flags' at clinical evaluation stage, such as early-onset severe atopy, recurrent/atypical infections, and autoimmunity. The diagnostic confirmation requires genetic testing. Precision medicine approaches like biological therapies and HSCT seem to provide promising results. It is worth noting that clinical and translational research in the field of IEIwA is currently paving the way for a more thorough understanding of the molecular bases of common allergic diseases.

Keloids and inflammation: the crucial role of IL-33 in epidermal changes

Introduction

Keloids are benign fibroproliferative disorders characterized by excessive collagen deposition and inflammation that extend beyond the original wound boundaries. IL-33 is an alarmin cytokine released upon cellular damage or stress. Dysregulation of IL-33 in epidermal keratinocytes compromises the skin barrier and triggers chronic inflammation.

Method

In this study, we first noticed an increased expression of IL-33 in the keratinocytes of keloid epidermis through histological staining. Then, an increased expression of IL-33 receptor (ST2) in the lymphocytes infiltrating the superficial dermis of keloid scars were identified through histological staining and flow cytometry analysis. The IFN-γ-IL-33 loop between lymphocytes and keratinocytes were further revealed by flow cytometry and Western blotting analysis. The abnormal keratinocyte differentiation in epiderm is mediated by IFN-γ-IL-33 loop were confirmed by in vitro studies in HaCaT cells via Western blotting analysis and immunofluorescence staining. Finally, the IFN-γ-IL-33 loop were also verified in cocultured peripheral blood mononuclear cells and HaCaT through ELISA analysis.

Results

Our results demonstrate that IL-33 levels are significantly elevated in the epidermis of keloid tissues, where it functions as an alarmin, promoting a chronic inflammatory response. We further reveal a feedback loop between IL-33 and interferon-gamma (IFN-γ), whereby IL-33 induces IFN-g production in lymphocytes, which in turn stimulates keratinocytes to produce more IL-33. This loop contributes to impaired keratinocyte differentiation and skin barrier dysfunction, exacerbating the inflammatory environment.

Discussion

By elucidating the role of the IL-33/ST2 axis in keloid formation, this research provides valuable insights into potential therapeutic targets for managing this challenging condition.

The big four in the pathogenesis and pathophysiology of prurigo nodularis: Interplay among type 2 inflammation, epidermal hyperplasia, dermal fibrosis, and itch from neuroimmune dysregulation

Prurigo nodularis (PN) is a distinct inflammatory dermatosis. It is characterized by intensely pruritic, firm nodules, typically 1 to 2 cm in diameter, which usually develop on the extensor surfaces of the extremities. Histopathologically, the following characteristics are observed in PN lesions: (1) dermal cellular infiltrates composed of type 2 inflammation-associated immune cells with lesional overexpression of type 2 cytokines (including interleukin [IL]-4, IL-13, and IL-31), (2) dermal fibrosis, and (3) epidermal hyperplasia with hyperkeratosis. Additionally, functional and structural alterations of cutaneous sensory nerve fibers profoundly contribute to itch in cooperation with type 2 inflammation. This abnormal interaction is referred to as neuroimmune dysregulation. The scratching behavior induced by itching from neuroimmune dysregulation initiates the development of prurigo nodules. This distinctive pathogenic feature of "itch-first" in PN is distinct from "inflammation-first" in atopic dermatitis, where the skin initially exhibits type 2 inflammation, which is subsequently followed by itching. The interplay between the four elements, namely type 2 inflammation, epidermal hyperplasia, dermal fibrosis, and itch resulting from neuroimmune dysregulation, appears to be pivotal in the pathogenesis and pathophysiology of PN.

Investigating the Potential Therapeutic Targeting of the JAK-STAT Pathway in Cerebrovascular Diseases: Opportunities and Challenges

Cerebrovascular disease (CVD) is a significant neurological condition resulting from pathological changes in the brain's blood supply and is currently the leading cause of death and disability worldwide. The progression of CVD is closely associated with endothelial damage, plaque formation, and thrombosis, driven by long-term alterations in vascular endothelial cells, smooth muscle cells, microglia, and other immune-inflammatory cells. Among the key molecular pathways involved, the Janus kinase/signal transducer and activator of transcription (JAK-STAT) signaling pathway plays a central role. Dysregulation of the JAK-STAT pathway is implicated in the pathogenesis of CVD by influencing the aforementioned cell types and associated pathological processes. Importantly, the role of the JAK-STAT pathway varies across different types of CVD and throughout different stages of disease progression (e.g., pre-morbid, acute, and chronic phases). This review examines the composition, activation, and regulation of the JAK-STAT pathway and summarizes recent findings on its involvement in CVD. We discuss the distinct roles of JAK-STAT signaling in various CVD conditions, the potential reasons for these differences, and explore the clinical translational prospects and technical challenges of targeting the JAK-STAT pathway for therapeutic intervention in CVD.

PeiTuQingXin formula alleviated atopic dermatitis symptoms via inhibiting TRADD/TRAF2/RIP1 complex mediated NF-κB signaling pathway activation

Atopic dermatitis (AD) is a chronic inflammatory skin disease with recurrent course, and traditional Chinese medicine (TCM) is regarded as an effective treatment. In this study, we aim to evaluate the potential effects and elucidate the mechanism of PTQX formula in alleviating a house dust mite (HDM)-induced AD model. NC/Nga mice were divided into Control, AD model and PTQX-treated and stimulated with HDM oinment. PTQX formula exerted significant anti-inflammatory effects, alleviated dermatitis performance, decreased the serum IgE by more than 2-fold, reduced the secretion level of other inflammatory cytokines and downregulated the Th2 cells ratio in lymph nodes. Treatment with PTQX formula reduced the level of inflammatory cytokines, which was measured by an inflammatory cytokine array kit (RayBio®). Kyoto Encyclopedia of Genes and Genomes pathway enrichment revealed the anti-inflammatory effect was exerted via regulation NF-κB and Toll-like receptor signaling pathway. Data independent acquisition (DIA) proteomics analysis results showed that the expression of totally 149 proteins were regulated by PTQX formula, while the expression of TRADD was significantly downregulated. According to the western blotting analysis, the PTQX group exhibitied an over 2-fold decreased expression of TRADD, TRAF2 and RIP1 compared with the AD group, accompanied by the inhibition of NF-κB signaling pathway activity. Collectively, this finding suggested that PTQX formula may exert effects by inhibiting the expression of the TRADD/TRAF2/RIP1 complex and downregulating the activity of the NF-κB signaling pathway.

N-Heterocyclic functionalized chalcone derivatives as anti-inflammatory agents for atopic dermatitis treatment by inhibiting JAK1/STAT3 signaling pathway

Atopic dermatitis (AD) is difficult to cure as a chronic inflammatory skin disease. In the present study, a series of N-heterocyclic functionalized chalcone derivatives have been prepared to investigate their in vitro and in vivo anti-inflammatory activities. The results indicated that many derivatives could effectively inhibit NO generation with low toxicity. In vivo studies revealed that 4f could improve the skin condition of AD-like mice, reduce inflammatory infiltration, inhibit the expressions of p-JAK1/JAK1 and p-STAT3/STAT3, and mitigate the excessive immune response on MC903-induced AD-like mice. The molecular docking study indicated that 4f had an obvious binding site with the target 4ehz and 6QHD. Therefore, these derivatives may be considered as potent agents for AD treatment by inhibiting JAK1/STAT3 signaling pathway.

d-Limonene inhibits cytokines and chemokines expression by regulating NF-kappaB and STAT in HaCat cells and DNCB-induced atopic dermatitis in BALB/c mice

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin disorder characterized by itching and redness, affecting individuals of all ages and significantly impairing their quality of life. The prevalence of AD is rising, posing serious health concern. Relief of itching is a primary treatment objective; however, steroid treatments can lead to adverse effects, including skin barrier thinning. Therefore, there is a pressing need for safer therapeutic alternatives. Limonene, a naturally occurring monocyclic monoterpene found in citrus peel oil, is widely utilized in food, cosmetics, and pharmaceuticals. Research has identified various biological activities of limonene, including antioxidative, anti-inflammatory, immunomodulatory, and antifibrotic properties. This study aims to investigate the therapeutic effects of limonene on atopic dermatitis, focusing on its anti-inflammatory potential.

METHODS

In this study, we investigated the expression levels of pro-inflammatory cytokines and chemokines, conducting histopathological analyses, and collecting physiological data from BALB/c mice with atopic-like dermatitis induced by 2,4-dinitrochlorobenzene (DNCB) and TNF-α/ IFN-γ-stimulated HaCaT cells.

RESULTS

In vitro studies indicated that limonene inhibited cytokine and chemokine expression in human keratinocytes and reduced phosphorylation in the MAPK, NF-κB, and JAK/STAT signaling pathways. In vivo, limonene mitigated DNCB-induced skin barrier damage and itching, improving physiological parameters such as trans-epidermal water loss, erythema, and ear thickness. Furthermore, it decreased the mRNA expression of pro-inflammatory cytokines.

CONCLUSION

Limonene exhibits significant anti-inflammatory effects, highlighting its therapeutic potential for treating atopic dermatitis.

Role of skin-homing t-cells in recurrent episodes of atopic dermatitis: a review

Atopic dermatitis (AD) is a chronic relapsing disease with complex pathogenesis. Among them, inflammation is one of the primary pathogenesis of AD. AD is characterized by infiltration of lymphocytes into the skin's dermis, and the skin homing of lymphocytes plays an essential role in the recurrence of AD. Currently, there is more and more evidence to support this view. This article reviews the relevant role of T lymphocyte skin-homing-related molecules in the recurrence of AD to provide a reference for the cure of AD.

Flavonoids as Natural Anti-Inflammatory Agents in the Atopic Dermatitis Treatment

Eczema is a complex autoimmune condition characterised mainly by inflammation and skin lesions along with physical and psychological comorbidities. Although there have been significant advances in understanding the mechanisms behind atopic dermatitis, conventionally available treatments yield inconsistent results and have some unintended consequences. In today's digital age, where knowledge is just a click away, natural-based supplements have been on the rise for a more "natural" treatment towards any type of disease. Natural compounds, particularly derived from medicinal plants, have piqued significant interest in the development of herbal remedies for chronic inflammatory skin conditions. Among many compounds, flavonoids have shown promise in treating eczema due to their strong anti-inflammatory, antioxidant, and anti-allergic properties, making them helpful in preventing allergic reactions, inflammation, and skin irritation. This review highlights the therapeutic potential of flavonoid-based bioactive compounds to manage eczema, emphasising the mechanisms of action. Additionally, providing a comprehensive analysis of the potential of emerging and established compounds, while bridging a gap between traditional and modern medicine. Flavonoids offer a variety of opportunities for further research and innovative formulations that can maximise its full benefits. Further combination of flavonoids with various approaches such as nanoencapsulation for enhanced bioavailability, hydrogel-based delivery systems for a controlled release, and additive manufacturing for personalised topical formulations, could align with future precision medicine needs.

Identification of a dual JAK3/TEC family kinase inhibitor for atopic dermatitis therapy

Atopic dermatitis (AD) is a chronic inflammatory skin disorder characterized by recurrent eczematous lesions and severe itching, for which clinical treatments are limited. Selectively inhibiting Janus Kinase 3 (JAK3) and tyrosine kinase expressed in hepatocellular carcinoma (TEC) family kinases is proposed as a promising strategy to treat AD with possible reduced side effects and enhanced efficacy. In this study, we developed a dual JAK3/TEC family kinase inhibitor ZZB, which demonstrated potent inhibitory activity with IC50 values of 0.89 nM against JAK3 and 11.56 nM against TEC kinase interleukin-2-inducible T-cell kinase (ITK). Docking studies revealed that ZZB forms a covalent bond with the unique cysteine residue at position 909 (Cys909) in JAK3 and Cys442 in ITK. Utilizing human peripheral blood mononuclear cells, we discovered ZZB selectively inhibits JAK3-dependent cytokines signaling and ITK-mediated CD4+ T cell activation. Moreover, in vitro studies indicated ZZB significantly suppresses the proliferation and differentiation of CD4+ T cells, as well as the cytolytic function of CD8+ T cells and NK cells. We then conducted a pharmacokinetic study in mice and observed a favorable pharmacokinetic profile for ZZB. In a mouse model of AD induced by repeated application of 2,4-dinitrochlorobenzene to the shaved dorsal skin, oral administration of ZZB (100 mg/kg) markedly improved skin condition and reduced immune cell infiltration, matching the efficacy of the positive drug dexamethasone. We conclude that the JAK3/TEC kinase inhibitor ZZB is a highly promising candidate for the treatment of AD.

Abrocitinib-associated adverse events: a real-world pharmacovigilance study using the FAERS database

BACKGROUND

Atopic dermatitis (AD) is a common chronic inflammatory skin disease. Janus kinase (JAK) modulates cytokines involved in AD pathophysiology, and JAK inhibitors have emerged as effective pharmacotherapeutic remedies for AD. Abrocitinib, an oral selective inhibitor of JAK1, is indicated for the management of moderate-to-severe AD. The current study evaluated the adverse events (AEs) associated with abrocitinib in a real-world setting.

METHODS

To quantify the signals of abrocitinib-associated AEs, we used the US Food and Drug Administration Adverse Event Reporting System (FAERS) for this pharmacovigilance study with two established pharmacovigilance methods.

RESULTS

A total of 1071 AEs of abrocitinib were investigated as the primary suspected from the FAERS to detect and characterize relevant safety signals. The analysis revealed 85 signals for abrocitinib. The most common AE for abrocitinib was drug ineffective. The signal strength of eczema herpeticum was 515.87 (277.80-957.98) and 510.59 (5148.65) and exhibited the highest strength for abrocitinib. Rare AEs such as aggravated condition, pruritus, and hypersensitivity were not listed on the label, and attention to these AEs is required.

CONCLUSION

The analysis of the AE signals may provide support for clinical monitoring and risk identification of abrocitinib.

Dichotomous STAT5 and STAT6 Activation in T Cells Reflects Cytokine Shifts Between Blood and Skin in Atopic Dermatitis

We assessed STAT activation in T cells in blood and skin of AD patients versus HC. pSTAT5+ T cells were increased in AD blood, correlated with disease activity, and were induced by common γc cytokines. Skin T cells exhibited a STAT6 signature, whereas only a subset was positive for STAT5. AD, atopic dermatitis; HC, healthy controls; STAT: Signal Transducers and Activators of Transcription.

Anti-Inflammatory Effects of Cannabigerol In Vitro and In Vivo Are Mediated Through the JAK/STAT/NFκB Signaling Pathway

Cannabinoid compounds have potential as treatments for a variety of conditions, with cannabigerol (CBG) being known for its anti-inflammatory properties. In this study, we investigated the effects of CBG in a cellular model of 1-chloro-2,4-dinitrobenzene (DNCB)-induced atopic dermatitis (AD). In the cellular model, we confirmed the cytotoxicity of CBG and downregulated the expression of inflammatory markers CCL26, IL1B, IL6, and TNF (p < 0.001). In the mouse model, clinical, histological, and immunological changes were analyzed. The results showed that CBG improved dermatitis severity score, epidermal thickness, and mast cell count and reduced inflammatory cytokines (Tslp, Il1b, Il4, Il6, Il13, Il17, Il18, Il22, and Il33) by qRT-PCR (p < 0.001). Western blot results showed modulated changes in JAK1, JAK2, TYK2, STAT1, STAT2, STAT3, p-STAT3, STAT6, and p-STAT6 (p < 0.05). Subsequently, p-IκBα, NF-κB, and p-NF-κB signaling factors were also reduced (p < 0.05), with corresponding changes in skin barrier factors. The results of this study indicate that CBG effectively alleviates AD-like symptoms and suggest the potential of CBG as a therapeutic agent.

Mechanisms and therapeutic prospect of the JAK-STAT signaling pathway in liver cancer

Liver cancer (LC) poses a significant global health challenge due to its high incidence and poor prognosis. Current systemic treatment options, such as surgery, chemotherapy, radiofrequency ablation, and immunotherapy, have shown limited effectiveness for advanced LC patients. Moreover, owing to the heterogeneous nature of LC, it is crucial to uncover more in-depth pathogenic mechanisms and develop effective treatments to address the limitations of the existing therapeutic modalities. Increasing evidence has revealed the crucial role of the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway in the pathogenesis of LC. The specific mechanisms driving the JAK-STAT pathway activation in LC, participate in a variety of malignant biological processes, including cell differentiation, evasion, anti-apoptosis, immune escape, and treatment resistance. Both preclinical and clinical investigations on the JAK-STAT pathway inhibitors have exhibited potential in LC treatment, thereby opening up avenues for the development of more targeted therapeutic strategies for LC. In this study, we provide an overview of the JAK-STAT pathway, delving into the composition, activation, and dynamic interplay within the pathway. Additionally, we focus on the molecular mechanisms driving the aberrant activation of the JAK-STAT pathway in LC. Furthermore, we summarize the latest advancements in targeting the JAK-STAT pathway for LC treatment. The insights presented in this review aim to underscore the necessity of research into the JAK-STAT signaling pathway as a promising avenue for LC therapy.

Cannabichromene as a Novel Inhibitor of Th2 Cytokine and JAK/STAT Pathway Activation in Atopic Dermatitis Models

Cannabichromene (CBC) is one of the main cannabinoids found in the cannabis plant, and although less well known than tetrahydrocannabinol (THC) and cannabidiol (CBD), it is gaining attention for its potential therapeutic benefits. To date, CBC's known mechanisms of action include anti-inflammatory, analgesic, antidepressant, antimicrobial, neuroprotective, and anti-acne effects through TRP channel activation and the inhibition of inflammatory pathways, suggesting that it may have therapeutic potential in the treatment of inflammatory skin diseases, such as atopic dermatitis (AD), but its exact mechanism of action remains unclear. Therefore, in this study, we investigated the effects of CBC on Th2 cytokines along with the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathways involved in AD pathogenesis. We used a 2,4-Dinitrochlorobenzene (DNCB)-induced BALB/c mouse model to topically administer CBC (0.1 mg/kg or 1 mg/kg). The results showed that skin lesion severity, ear thickness, epithelial thickness of dorsal and ear skin, and mast cell infiltration were significantly reduced in the 0.1 mg/kg CBC-treated group compared with the DNCB-treated group (p < 0.001). In addition, real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis showed a significant decrease in the mRNA expression of Th2 cytokines (TSLP, IL-4, IL-13) and inflammatory mediators (IFN-γ, IL-1β, IL-6, IL-17, IL-18, and IL-33) (p < 0.05). Western blot analysis also revealed a significant decrease in JAK1, JAK2, STAT1, STAT2, STAT3, and STAT6 protein expression (p < 0.05). These results suggest that CBC is a promising candidate for the treatment of AD and demonstrates the potential to alleviate AD symptoms by suppressing the Th2 immune response.

STATs, promising targets for the treatment of autoimmune and inflammatory diseases

Cytokines play a crucial role in the pathophysiology of autoimmune and inflammatory diseases, with over 50 cytokines undergoing signal transduction through the Signal Transducers and Activators of Transcription (STAT) signaling pathway. Recent studies have solidly confirmed the pivotal role of STATs in autoimmune and inflammatory diseases. Therefore, this review provides a detailed summary of the immunological functions of STATs, focusing on exploring their mechanisms in various autoimmune and inflammatory diseases. Additionally, with the rapid advancement of structural biology in the field of drug discovery, many STAT inhibitors have been identified using structure-based drug design strategies. In this review, we also examine the structures of STAT proteins and compile the latest research on STAT inhibitors currently being tested in animal models and clinical trials for the treatment of immunological diseases, which emphasizes the feasibility of STATs as promising therapeutic targets and provides insights into the design of the next generation of STAT inhibitors.

Efficacy and Potential Mechanisms of Naringin in Atopic Dermatitis

Atopic dermatitis (AD) is one of the most prevalent chronic inflammatory skin diseases. Topical treatments are recommended for all patients regardless of severity, making it essential to develop an effective topical AD treatment with minimal side effects; We investigated the efficacy of topical application of naringin in AD and explored the possible mechanisms using an AD mouse model induced by 1-chloro-2,4-dinitrobenzene (DNCB). Clinical, histological, and immunological changes related to AD and Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling proteins in the skin tissues were measured as outcomes; Naringin treatment resulted in a significant improvement in dermatitis severity score and reduced epidermal thickness and mast cell count in the skin (p < 0.05). Naringin also demonstrated the ability to inhibit DNCB-induced changes in interleukin (IL) 4, chemokine (C-C motif) ligand (CCL) 17, CCL22, IL1β, interferon-gamma (IFN-γ), and tumor necrosis factor-alpha (TNF-α) levels by quantitative real-time polymerase chain reaction (qRT-PCR) and IL13 by enzyme-linked immunosorbent assay (ELISA) (p < 0.05). Western blot results exhibited the decreased JAK1, JAK2, STAT1, STAT3, phospho-STAT3, and STAT6 expression in the naringin-treated groups (p < 0.05); The findings of this study suggest that topical naringin may effectively improve the symptoms of AD and could be used as a therapeutic agent for AD.

JAK inhibitor selectivity: new opportunities, better drugs?

Cytokines function as communication tools of the immune system, serving critical functions in many biological responses and shaping the immune response. When cytokine production or their biological activity goes awry, the homeostatic balance of the immune response is altered, leading to the development of several pathologies such as autoimmune and inflammatory disorders. Cytokines bind to specific receptors on cells, triggering the activation of intracellular enzymes known as Janus kinases (JAKs). The JAK family comprises four members, JAK1, JAK2, JAK3 and tyrosine kinase 2, which are critical for intracellular cytokine signalling. Since the mid-2010s multiple JAK inhibitors have been approved for inflammatory and haematological indications. Currently, approved JAK inhibitors have demonstrated clinical efficacy; however, improved selectivity for specific JAKs is likely to enhance safety profiles, and different strategies have been used to accomplish enhanced JAK selectivity. In this update, we discuss the background of JAK inhibitors, current approved indications and adverse effects, along with new developments in this field. We address the issue of JAK selectivity and its relevance in terms of efficacy, and describe new modalities of JAK targeting, as well as new aspects of JAK inhibitor action.

Tofacitinib ameliorates skin inflammation in a patient with severe autosomal recessive congenital ichthyosis

Autosomal recessive congenital ichthyosis (ARCI) is a genetically heterogeneous disorder with aberrant skin scaling and increased transepidermal water loss (TEWL). Current treatments for ARCI are limited and suboptimal. We present the case of a 27-year-old man with ARCI resulting from a homozygous missense variant in TGM1. RNA-sequencing of lesional skin revealed aberrant Janus kinase-signal transducer and activator of transcription signalling, providing a rationale for innovative treatment with a Janus kinase inhibitor. We prescribed oral tofacitinib (11 mg daily) for 26 weeks. Rapid improvements in erythema and fissuring occurred within the first month. Sustained reductions in 5-D itch scale and Dermatology Life Quality Index scores were also observed. TEWL decreased for the first 10 weeks but increased thereafter. Tofacitinib downregulated inflammatory genes and pathways, while enhancing skin barrier markers. Moreover, transglutaminase 1 distribution was normalized although enzymatic activity remained deficient. This study suggests that oral tofacitinib may be a useful therapy to consider for patients with ARCI.

A novel approach with tofacitinib for the management of keratoderma blennorrhagicum in reactive arthritis: a case report

Reactive arthritis(ReA), a form of arthritis occurring post-infection, manifests with antecedent infection symptoms, arthritis, and extra-articular manifestations, categorizing it as spondyloarthritis. "Keratoderma blennorrhagicum" (characterized by pustular hyperkeratosis on palms and soles, resembling pustular psoriasis) represents the most typical skin manifestation of ReA, occurring in acute or chronic phases. Severe lesions necessitate systemic disease modifying anti-rheumatic drugs (DMARDs) or biologic therapies. This article reports a case of ReA with sacroiliitis and widespread pustular eruptions following a urinary tract infection. Treatment with sulfasalazine and thalidomide significantly improved sacroiliitis, but the skin rash remained persistent and recurring. Subsequent use of adalimumab and secukinumab resulted in worsening skin rash, prompting a switch to tofacitinib, leading to a remarkable improvement in pustular eruptions after 20 days of treatment. This case demonstrates successful application of tofacitinib in treating severe keratoderma blennorrhagicum refractory to conventional DMARDs and biologics, offering insights into JAK inhibition for challenging rheumatic diseases with skin involvement.

Reynoutria japonica consisted of emodin-8-β-D-glucoside ameliorates Dermatophagoides farinae extract-induced atopic dermatitis-like skin inflammation in mice by inhibiting JAK/STAT signaling

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by skin barrier dysfunction and chronic inflammatory responses. Reynoutria japonica, known as Huzhang in traditional Chinese Medicine, can enhance blood circulation to eliminate wind pathogens and terminate coughing. Despite pharmacological evidence supporting the efficacy of R. japonica in suppressing edema-induced skin inflammation or connective tissue diseases, its pharmaceutical potential for treating AD-like skin inflammation remains unexplored. This study investigated the possible effects of R. japonica ethanol extract (RJE) on Dermatophagoides farinae extract (DfE)-induced AD-like skin inflammation in NC/Nga mice. To elucidate the underlying mechanisms by which RJE inhibits skin inflammation, we examined the effect of RJE on IFN-γ/TNF-α-induced signal transducer and activator of transcription (STAT) signaling in human epidermal keratinocytes (HEKs) and human dermal fibroblasts (HDFs). Our findings revealed that RJE mitigates DfE-induced AD-like symptoms and skin barrier disruptions in mouse skin lesions. Moreover, RJE attenuated DfE-induced mast cell infiltration and serum levels of inflammatory cytokines (IL-1α, IL-1β, IL-6, IL-23, IFN-γ, TNF-α, and GM-CSF). RJE also inhibited IFN-γ/TNF-α-induced chemokine levels and STAT3 phosphorylation in HEKs and HDFs. Virtual binding analysis of the RJE components suggested that emodin-8-β-D-glucoside binds to Janus kinase (JAK) 1/2, thereby suppressing STAT signaling, which was confirmed by Western blot analysis. In conclusion, our results suggest that RJE may alleviate DfE-induced skin barrier dysfunction by inhibiting JAK/STAT signaling and the proinflammatory immune response through the suppression of inflammatory mediators in AD-like skin disease. These findings suggest that RJE has potential as an effective therapy for AD management.

Immunologic Profiling of Immune-Related Cutaneous Adverse Events with Checkpoint Inhibitors Reveals Polarized Actionable Pathways

PURPOSE

Immune-related cutaneous adverse events (ircAE) occur in ≥50% of patients treated with checkpoint inhibitors, but the underlying mechanisms for ircAEs are poorly understood.

EXPERIMENTAL DESIGN

Phenotyping/biomarker analyses were conducted in 200 patients on checkpoint inhibitors [139 with ircAEs and 61 without (control group)] to characterize their clinical presentation and immunologic endotypes. Cytokines were evaluated in skin biopsies, skin tape strip extracts, and plasma using real-time PCR and Meso Scale Discovery multiplex cytokine assays.

RESULTS

Eight ircAE phenotypes were identified: pruritus (26%), maculopapular rash (MPR; 21%), eczema (19%), lichenoid (11%), urticaria (8%), psoriasiform (6%), vitiligo (5%), and bullous dermatitis (4%). All phenotypes showed skin lymphocyte and eosinophil infiltrates. Skin biopsy PCR revealed the highest increase in IFNγ mRNA in patients with lichenoid (P < 0.0001) and psoriasiform dermatitis (P < 0.01) as compared with patients without ircAEs, whereas the highest IL13 mRNA levels were detected in patients with eczema (P < 0.0001, compared with control). IL17A mRNA was selectively increased in psoriasiform (P < 0.001), lichenoid (P < 0.0001), bullous dermatitis (P < 0.05), and MPR (P < 0.001) compared with control. Distinct cytokine profiles were confirmed in skin tape strip and plasma. Analysis determined increased skin/plasma IL4 cytokine in pruritus, skin IL13 in eczema, plasma IL5 and IL31 in eczema and urticaria, and mixed-cytokine pathways in MPR. Broad inhibition via corticosteroids or type 2 cytokine-targeted inhibition resulted in clinical benefit in these ircAEs. In contrast, significant skin upregulation of type 1/type 17 pathways was found in psoriasiform, lichenoid, bullous dermatitis, and type 1 activation in vitiligo.

CONCLUSIONS

Distinct immunologic ircAE endotypes suggest actionable targets for precision medicine-based interventions.

Genetic and Immunological Pathogenesis of Atopic Dermatitis

Type 2 immune-mediated diseases give a clear answer to the issue of nature (genetics) versus nurture (environment). Both genetics and environment play vital complementary roles in the development of atopic dermatitis (AD). As a key component of the atopic march, AD demonstrates the interactive nature of genetic and environmental contributions to atopy. From sequence variants in the epithelial barrier gene encoding FLG to the hygiene hypothesis, AD combines a broad array of contributions into a single syndrome. This review will focus on the genetic contribution to AD and where genetics facilitates the elicitation or enhancement of AD pathogenesis.

The Fifth Bioelectronic Medicine Summit: today's tools, tomorrow's therapies

The emerging field of bioelectronic medicine (BEM) is poised to make a significant impact on the treatment of several neurological and inflammatory disorders. With several BEM therapies being recently approved for clinical use and others in late-phase clinical trials, the 2022 BEM summit was a timely scientific meeting convening a wide range of experts to discuss the latest developments in the field. The BEM Summit was held over two days in New York with more than thirty-five invited speakers and panelists comprised of researchers and experts from both academia and industry. The goal of the meeting was to bring international leaders together to discuss advances and cultivate collaborations in this emerging field that incorporates aspects of neuroscience, physiology, molecular medicine, engineering, and technology. This Meeting Report recaps the latest findings discussed at the Meeting and summarizes the main developments in this rapidly advancing interdisciplinary field. Our hope is that this Meeting Report will encourage researchers from academia and industry to push the field forward and generate new multidisciplinary collaborations that will form the basis of new discoveries that we can discuss at the next BEM Summit.

Comparative Study of Hematological Parameters and Biomarkers of Immunity and Inflammation in Patients with Psoriasis and Atopic Dermatitis

Background and Objectives: There are no studies regarding comparative analysis of hematological parameters in patients with psoriasis (PsO) and atopic dermatitis (AD), whereas studies examining serum biomarkers of immunity and inflammation in these entities are scarce and contradictory. We aimed to compare such parameters in patients with PsO and AD. Materials and Methods: Patients with PsO (n = 40) and AD (n = 40) were consecutively included in this cross-sectional study. Hematological parameters and biomarkers of immunity and inflammation (interferon-gamma (IFN-γ), interleukine (IL)-22 and C-reactive protein (CRP)) were determined. Results: While the mean corpuscular volume (MCV) was higher in the PsO group vs. the AD group (p < 0.05), there was no difference in the other examined parameters between groups. A higher neutrophil-to-lymphocyte ratio (NLR) was found in patients with AD > 50 years vs. patients with PsO of similar age (p < 0.05). Higher IL-22 levels were found in patients with AD < 50 years vs. patients with PsO of similar age (p < 0.05). Lower IL-22 levels were found in patients with AD > 50 years vs. patients with AD < 50 years (p < 0.05). Patients with PsO and with comorbidities had lower platelets (PLT), plateletcrit (PCT) and platelet-to-lymphocyte ratio (PLR), whereas lymphocytes, red cell distribution width-to-PLT ratio (RPR) and mean platelet volume/PLT ratio (MPR) were higher vs. PsO patients without comorbidities. Patients with AD and with comorbidities had lower PCT and PLR, whereas RPR was higher vs. AD patients without comorbidities. Conclusions: A higher pro-inflammatory state (i.e., higher NLR and IL-22) was found in AD vs. PsO in age-specific groups. A higher pro-inflammatory state (i.e., as reflected by platelet indexes) was found in both diseases with comorbidities.