JAK-STAT signaling pathway in the pathogenesis of atopic dermatitis: An updated review

A systematic review investigating the proportion of clinical images shared in prospective randomized controlled trials involving patients with atopic dermatitis and systemic pharmacotherapy

For individuals with atopic dermatitis (AD), interpreting scientific papers that present clinical outcomes including the Eczema Area and Severity Index (EASI) and Investigators Global Assessment may be difficult. When compared to tabulated data and graphs, images from before and after treatment are often far more meaningful to these patients that ultimately will be candidates for the treatment. This systematic review focused on determining the frequency of clinical image sharing in AD research.

Conducted in accordance with PRISMA guidelines, the review concentrated on randomized controlled trials that investigated predefined and available systemic treatments for AD. The search was performed in the MEDLINE database for studies published from the inception until 21 December 2023.

The review included 60 studies, encompassing 17,799 randomized patients. Across these studies, 16 images representing 6 patients were shared in the manuscripts, leading to a sharing rate of 0.3‰.

The almost missing inclusion of patient images in clinical trial publications hinders patient understanding. Adding images to scientific manuscripts could significantly improve patients' comprehension of potential treatment outcomes. This review highlights the need for authors, the pharmaceutical industry, study sponsors, and publishers to enhance and promote patient information through increased use of visual data.

Patients' preferences for systemic treatment of atopic dermatitis: safety and efficacy count the most

BACKGROUND

The advent of biologics and janus kinase inhibitors has revolutionized treatment of atopic dermatitis (AD).

OBJECTIVE

To investigate preferences of patients with AD for attributes of currently approved systemic treatments and assess influencing factors.

METHODS

An online discrete choice experiment was conducted in patients with AD throughout Germany to analyze preferences for outcome (probability of (almost) clear skin at week 16, probability of significant itch improvement, time to onset of itch relief and type of side effects) and process attributes (application method and frequency of laboratory tests).

RESULTS

Participants (n = 182, 75.3% female) considered side effects (Relative Importance Score (RIS): 31.2), (almost) clear skin (RIS: 24.2) and probability of itch improvement (RIS: 16.0) most important. Application method (RIS: 14.4), time to onset of itch relief (RIS: 7.4) and frequency of laboratory tests (RIS: 6.8) were less relevant. Preferences were significantly influenced by sex, age, psychiatric comorbidity, current therapy and health-related quality of life according to multivariate regression analysis.

CONCLUSIONS

Participants attached great importance to safety and symptom control. However, preferences were also dependent on individual characteristics, underscoring the importance of personal counseling. Conjoined with medical considerations, patients' preferences have fundamental impact on shared decisions for treatment of AD.

Monotropein mitigates atopic dermatitis-like skin inflammation through JAK/STAT signaling pathway inhibition

Atopic dermatitis (AD) is a globally increasing chronic inflammatory skin disease with limited and potentially side-effect-prone treatment options. Monotropein is the predominant iridoid glycoside in Morinda officinalis How roots, which has previously shown promise in alleviating AD symptoms. This study aimed to systematically investigate the pharmacological effects of monotropein on AD using a 2, 4-dinitrochlorobenzene (DNCB)/Dermatophagoides farinae extract (DFE)-induced AD mice and tumor necrosis factor (TNF)-α/interferon (IFN)-γ-stimulated keratinocytes. Oral administration of monotropein demonstrated a significant reduction in AD phenotypes, including scaling, erythema, and increased skin thickness in AD-induced mice. Histological analysis revealed a marked decrease in immune cell infiltration in skin lesions. Additionally, monotropein effectively downregulated inflammatory markers, encompassing pro-inflammatory cytokines, T helper (Th)1 and Th2 cytokines, and pro-inflammatory chemokines in skin tissues. Notably, monotropein also led to a considerable decrease in serum immunoglobulin (Ig)E and IgG2a levels. At a mechanistic level, monotropein exerted its anti-inflammatory effects by suppressing the phosphorylation of Janus kinase / signal transducer and activator of transcription proteins in both skin tissues of AD-induced mice and TNF-α/IFN-γ-stimulated keratinocytes. In conclusion, monotropein exhibited a pronounced alleviation of AD symptoms in the experimental models used. These findings underscore the potential application of monotropein as a therapeutic agent in the context of AD, providing a scientific basis for further exploration and development.

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.

Case report: Sequential therapy with dupilumab and baricitinib for severe alopecia areata with atopic dermatitis in children

An 8-year-old female child presented with patchy hair loss for 1 year, accompanied by eyebrow loss for 6 months. Microscopic examination of the hair confirmed the features of active stage alopecia areata, with a Severity of Alopecia Tool (SALT) score of 70%. The diagnosis was severe alopecia areata. The patient had a history of atopic dermatitis since infancy, with recurrent episodes of scattered papules and pruritus for 8 years. Initial treatment involved subcutaneous injections of dupilumab 300mg every 2 weeks for 6 months, resulting in a reduction of SALT score to 20% and improvement of atopic dermatitis symptoms. Discontinuation of Dupilumab and initiation of daily oral Baricitinib at a dose of 2mg for a duration of 5 months. According to the SALT score evaluation, the severity of hair loss was less than 10% and there was significant regrowth of hair. No significant adverse reactions were observed during the treatment period.

Cutaneous adverse reactions associated with COVID-19 vaccines: Current evidence and potential immune mechanisms

As the number of vaccinated individuals has increased, there have been increasing reports of cutaneous hypersensitivity reactions. The main COVID-19 vaccines administered include messenger ribonucleic acid vaccines, non-replicating viral vector vaccines, inactivated whole-virus vaccines, and protein-based vaccines. These vaccines contain active components such as polyethylene glycol, polysorbate 80, aluminum, tromethamine, and disodium edetate dihydrate. Recent advances in understanding the coordination of inflammatory responses by specific subsets of lymphocytes have led to a new classification based on immune response patterns. We categorize these responses into four patterns: T helper (Th)1-, Th2-, Th17/22-, and Treg-polarized cutaneous inflammation after stimulation of COVID-19 vaccines. Although the association between COVID-19 vaccination and these cutaneous adverse reactions remains controversial, the occurrence of rare dermatoses and their short intervals suggest a possible relationship. Despite the potential adverse reactions, the administration of COVID-19 vaccines is crucial in the ongoing battle against severe acute respiratory syndrome coronavirus 2.

Involvement of Janus kinase-dependent Bcl-xL overexpression in steroid resistance of group 2 innate lymphoid cells in asthma

The mechanisms underlying the development of steroid resistance in asthma remain unclear. To establish whether as well as the mechanisms by which the activation of Janus kinases (JAKs) is involved in the development of steroid resistance in asthma, murine steroid-resistant models of the proliferation of group 2 innate lymphoid cells (ILC2s) in vitro and asthmatic airway inflammation in vivo were analysed. ILC2s in the lungs of BALB/c mice were sorted and then incubated with IL-33, thymic stromal lymphopoietin (TSLP), and/or IL-7 with or without dexamethasone (10 nM), the pan-JAK inhibitor, delgocitinib (1-10 000 nM), and/or the Bcl-xL inhibitor, navitoclax (1-100 nM), followed by the detection of viable and apoptotic cells. The anti-apoptotic factor, Bcl-xL was detected in ILC2s by flow cytometry. As a steroid-resistant asthma model, ovalbumin (OVA)-sensitized BALB/c mice were intratracheally challenged with OVA at a high dose of 500 μg four times. Dexamethasone (1 mg/kg, i.p.), delgocitinib (3-30 mg/kg, p.o.), or navitoclax (30 mg/kg, p.o.) was administered during the challenges. Cellular infiltration into the lungs was analysed by flow cytometry. Airway remodelling was histologically evaluated. The following results were obtained. (1) Cell proliferation concomitant with a decrease in apoptotic cells was induced when ILC2s were cultured with TSLP and/or IL-7, and was potently inhibited by dexamethasone. In contrast, when the culture with TSLP and IL-7 was performed in the presence of IL-33, the proliferative response exhibited steroid resistance. Steroid-resistant ILC2 proliferation was suppressed by delgocitinib in a concentration-dependent manner. (2) The culture with IL-33, TSLP, and IL-7 induced the overexpression of Bcl-xL, which was clearly inhibited by delgocitinib, but not by dexamethasone. When ILC2s were treated with navitoclax, insensitivity to dexamethasone was significantly cancelled. (3) The development of airway remodelling and the infiltration of ILC2s into the lungs in the asthma model were not suppressed by dexamethasone, but were dose-dependently inhibited by delgocitinib. Combination treatment with dexamethasone and either delgocitinib or navitoclax synergistically suppressed these responses. Therefore, JAKs appear to play significant roles in the induction of steroid resistance by up-regulating Bcl-xL in ILC2s. The inhibition of JAKs and Bcl-xL has potential as pharmacotherapy for steroid-resistant asthma, particularly that mediated by ILC2s.

Model of Chronic Itch in Aged Mice: Beneficial Effects of Drugs Affecting Descending Modulatory Systems

Pruritus in the elderly, particularly those cases without skin dryness or other identifiable causes, makes treatment challenging due to the lack of evidence regarding the therapeutic effects of antipruritics. This study proposes an age-related alloknesis mouse model for an evaluation system for such cases, and aimed to investigate the effectiveness and mechanisms of action of several drugs commonly used as antipruritics in Japan, utilizing this model. Mice 69-80 weeks old were used as aged mice, and the level of mechanical alloknesis was counted as the number of scratching behaviours in response to innocuous stimuli. Bepotastine, neurotropin, pregabalin, baricitinib, and abrocitinib were used as antipruritics, and yohimbine and methysergide as inhibitors of the descending inhibitory pathway. The findings suggest that mechanical alloknesis in aged mice is a suitable animal model for assessing pruritus in the elderly without xerosis, and pregabalin, neurotropin, baricitinib, and abrocitinib may be effective antipruritics in the elderly through activating both the noradrenergic and serotonergic descending inhibitory pathways. These findings may be useful for the selection of antipruritics for pruritus in the elderly without skin lesions or dryness.

Prurigo Nodularis: Pathogenesis and the Horizon of Potential Therapeutics

Chronic pruritus that lasts for over 6 weeks can present in various forms, like papules, nodules, and plaque types, with prurigo nodularis (PN) being the most prevalent. The pathogenesis of PN involves the dysregulation of immune cell-neural circuits and is associated with peripheral neuropathies, possibly due to chronic scratching. PN is a persistent and challenging condition, involving complex interactions among the skin, immune system, and nervous system. Lesional skin in PN exhibits the infiltration of diverse immune cells like T cells, eosinophils, macrophages, and mast cells, leading to the release of inflammatory cytokines and itch-inducing substances. Activated sensory nerve fibers aggravate pruritus by releasing neurotransmitters, perpetuating a vicious cycle of itching and scratching. Traditional treatments often fail, but recent advancements in understanding the inflammatory and itch transmission mechanisms of PN have paved the way for innovative therapeutic approaches, which are explored in this review.

IL20Rb aggravates pulmonary fibrosis through enhancing bone marrow derived profibrotic macrophage activation

Idiopathic pulmonary fibrosis (IPF) is one of the most fatal chronic interstitial lung diseases with unknown pathogenesis, current treatments cannot truly reverse the progression of the disease. Pulmonary macrophages, especially bone marrow derived pro-fibrotic macrophages, secrete multiple kinds of profibrotic mediators (SPP1, CD206, CD163, IL-10, CCL18…), thus further promote myofibroblast activation and fibrosis procession. IL20Rb is a cell-surface receptor that belongs to IL-20 family. The role of IL20Rb in macrophage activation and pulmonary fibrosis remains unclear. In this study, we established a bleomycin-induced pulmonary fibrosis model, used IL4/13-inducing THP1 cells to induce profibrotic macrophage (M2-like phenotype) polarization models. We found that IL20Rb is upregulated in the progression of pulmonary fibrosis, and its absence can alleviate the progression of pulmonary fibrosis. In addition, we demonstrated that IL20Rb promote the activation of bone marrow derived profibrotic macrophages by regulating the Jak2/Stat3 and Pi3k/Akt signaling pathways. In terms of therapeutic strategy, we used IL20Rb neutralizing antibodies for animal administration, which was found to alleviate the progression of IPF. Our results suggest that IL20Rb plays a profibrotic role by promoting profibrotic macrophage polarization, and IL20Rb may become a potential therapeutic target for IPF. Neutralizing antibodies against IL20Rb may become a potential drug for the clinical treatment of IPF.

Reversible effects on female rat fertility with abrocitinib, a Janus kinase 1 inhibitor

BACKGROUND

Abrocitinib is a Janus kinase (JAK) 1 selective inhibitor approved for the treatment of atopic dermatitis. Female reproductive tissues were unaffected in general toxicity studies, but an initial female rat fertility study resulted in adverse effects at all doses evaluated. A second rat fertility study was conducted to evaluate lower doses and potential for recovery.

METHODS

This second study had 4 groups of 20 females each administered abrocitinib (0, 3, 10, or 70 mg/kg/day) 2 weeks prior to cohabitation through gestation day (GD) 7. In addition, 2 groups of 20 rats (0 or 70 mg/kg/day) were dosed for 3 weeks followed by a 4-week recovery period before mating. All mated females were evaluated on GD 14.

RESULTS

No effects were observed at ≤10 mg/kg/day. At 70 mg/kg/day (29x human exposure), decreased pregnancy rate, implantation sites, and viable embryos were observed. All these effects reversed 4 weeks after the last dose.

CONCLUSIONS

Based on these data and literature on the potential role of JAK signaling in implantation, we hypothesize that these effects may be related to JAK1 inhibition and, generally, that peri-implantation effects such as these, in the absence of cycling or microscopic changes in nonpregnant female reproductive tissues, are anticipated to be reversible.

Successful treatment of actinic prurigo with baricitinib in an 8-year-old child: A case report

Actinic prurigo is a rare photodermatosis characterized by pruritic papulonodular lesions. Treatment is challenging, especially in children, as sun protection strategies need to be rigorously implemented and symptoms often persist throughout the year. Herein, we present a case of actinic prurigo in an 8-year-old patient with rapid and successful relief with baricitinib.

JAK/STAT Inhibition Normalizes Lipid Composition in 3D Human Epidermal Equivalents Challenged with Th2 Cytokines

Derangement of the epidermal barrier lipids and dysregulated immune responses are key pathogenic features of atopic dermatitis (AD). The Th2-type cytokines interleukin IL-4 and IL-13 play a prominent role in AD by activating the Janus Kinase/Signal Transduction and Activator of Transcription (JAK/STAT) intracellular signaling axis. This study aimed to investigate the role of JAK/STAT in the lipid perturbations induced by Th2 signaling in 3D epidermal equivalents. Tofacitinib, a low-molecular-mass JAK inhibitor, was used to screen for JAK/STAT-mediated deregulation of lipid metabolism. Th2 cytokines decreased the expression of elongases 1, 3, and 4 and serine-palmitoyl-transferase and increased that of sphingolipid delta(4)-desaturase and carbonic anhydrase 2. Th2 cytokines inhibited the synthesis of palmitoleic acid and caused depletion of triglycerides, in association with altered phosphatidylcholine profiles and fatty acid (FA) metabolism. Overall, the ceramide profiles were minimally affected. Except for most sphingolipids and very-long-chain FAs, the effects of Th2 on lipid pathways were reversed by co-treatment with tofacitinib. An increase in the mRNA levels of CPT1A and ACAT1, reduced by tofacitinib, suggests that Th2 cytokines promote FA beta-oxidation. In conclusion, pharmacological inhibition of JAK/STAT activation prevents the lipid disruption caused by the halted homeostasis of FA metabolism.

Kahweol Inhibits Pro-Inflammatory Cytokines and Chemokines in Tumor Necrosis Factor-α/Interferon-γ-Stimulated Human Keratinocyte HaCaT Cells

Atopic dermatitis (AD), marked by intense itching and eczema-like lesions, is a globally increasing chronic skin inflammation. Kahweol, a diterpene that naturally occurs in coffee beans, boasts anti-inflammatory, antioxidative, and anti-cancer properties. This research explores the anti-inflammatory action of kahweol on HaCaT human keratinocytes stimulated by tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), focusing on key signal transduction pathways. Our results demonstrate that kahweol markedly reduces the production of IL-1β, IL-6, C-X-C motif chemokine ligand 8, and macrophage-derived chemokine in TNF-α/IFN-γ-activated HaCaT cells. Furthermore, it curtails the phosphorylation of key proteins in the mitogen-activated protein kinase (MAPK) pathways, including c-Jun N-terminal kinase, extracellular signal-regulated kinase, and p38. Additionally, kahweol impedes the phosphorylation and nuclear translocation of the NF-κB p65 subunit and constrains its DNA-binding capability. It also hampers the phosphorylation, nuclear translocation, and DNA-binding activities of signal transducer and activator of transcription 1 (STAT1) and STAT3. Collectively, these findings suggest that kahweol hinders the generation of cytokines and chemokines in inflamed keratinocytes by inhibiting the MAPK, NF-κB, and STAT cascades. These insights position kahweol as a promising agent for dermatological interventions, especially in managing inflammatory skin conditions such as AD.

Neuroimmune interplay during type 2 inflammation: Symptoms, mechanisms, and therapeutic targets in atopic diseases

Type 2 inflammation is characterized by overexpression and heightened activity of type 2 cytokines, mediators, and cells that drive neuroimmune activation and sensitization to previously subthreshold stimuli. The consequences of altered neuroimmune activity differ by tissue type and disease; they include skin inflammation, sensitization to pruritogens, and itch amplification in atopic dermatitis and prurigo nodularis; airway inflammation and/or hyperresponsiveness, loss of expiratory volume, airflow obstruction and increased mucus production in asthma; loss of sense of smell in chronic rhinosinusitis with nasal polyps; and dysphagia in eosinophilic esophagitis. We describe the neuroimmune interactions that underlie the various sensory and autonomic pathologies in type 2 inflammatory diseases and present recent advances in targeted treatment approaches to reduce type 2 inflammation and its associated symptoms in these diseases. Further research is needed to better understand the neuroimmune mechanisms that underlie chronic, sustained inflammation and its related sensory pathologies in diseases associated with type 2 inflammation.

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.

Prurigo: review of its pathogenesis, diagnosis, and treatment

Prurigo is a reactive, hyperplastic skin condition characterized by pruritic papules, plaques, and/or nodules. The temporal classification includes acute/subacute and chronic disease (≥ 6 weeks), with different clinical variants, synonymies, and underlying etiological factors. The immunology of chronic prurigo shows similarities with atopic dermatitis due to the involvement of IL-4 and IL-13, IL-22, and IL-31. Treatment includes antihistamines, topical steroids, dupilumab, and JAK inhibitors. Several conditions manifest clinically as prurigo-like lesions, and the correct clinical diagnosis must precede correct treatment. Furthermore, chronic prurigos represent a recalcitrant and distressing dermatosis, and at least 50% of these patients have atopic diathesis, the treatment of which may induce adverse effects, especially in the elderly. The quality of life is significantly compromised, and topical treatments are often unable to control symptoms and skin lesions. Systemic immunosuppressants, immunobiologicals, and JAK inhibitors, despite the cost and potential adverse effects, may be necessary to achieve clinical improvement and quality of life. This manuscript reviews the main types of prurigo, associated diseases, their immunological bases, diagnosis, and treatment.

Circadian rhythm of cutaneous pruritus

One of the most common and significant symptoms for skin disorders is pruritus. Additionally, it serves as a significant catalyst for the exacerbation or reoccurrence of skin diseases. Pruritus seriously affects patients' physical and mental health, and even the quality of life. It brings a heavy burden to the patients, the families, even the whole society. The pathogenesis and regulation mechanisms for pruritus are complicated and have not yet been elucidated. Previous clinical studies have shown that itch worsens at night in scabies, chronic pruritus, atopic dermatitis, and psoriasis, suggesting that skin pruritus may change with circadian rhythm. Cortisol, melatonin, core temperature, cytokines, and prostaglandins are the main regulatory factors of the circadian rhythm of pruritus. Recent studies have shown that some CLOCK genes, such as BMAL1, CLOCK, PER, and CRY, play an important role in the regulation of the circadian rhythm of pruritus by regulating the Janus tyrosine kinase (JAK)-signal transducer and activator of transcription (STAT) and nuclear factor kappa-B (NF-κB) signaling pathways. However, the mechanisms for circadian clock genes in regulation of circadian rhythm of pruritus have not been fully elucidated. Further studies on the mechanism of circadian clock genes in the regulation of circadian rhythm of pruritus will lay a foundation for elucidating the regulatory mechanisms for pruritus, and also provide new ideas for the control of pruritus and the alleviation of skin diseases.

Upadacitinib treatment in a real-world difficult-to-treat atopic dermatitis patient cohort

BACKGROUND

Upadacitinib was the first JAK-1 selective inhibitor registered for the treatment of moderate-to-severe atopic dermatitis (AD). Although efficacy and safety have been shown in clinical trials, real-world data on the use of upadacitinib in patients that have been treated with other immunosuppressants and targeted therapies is limited.

OBJECTIVES

To provide real-world evidence on the use of upadacitinib treatment in moderate-to-severe atopic dermatitis.

METHODS

In this prospective observational single-centre study, all AD patients treated with upadacitinib treatment in the context of standard care were included between August 2021 and September 2022. Clinical outcome measures and adverse events (AEs) were analysed.

RESULTS

Forty-eight patients were included. The majority (n = 39; 81%) had failed (ineffectiveness) on other targeted therapies, including other JAK inhibitors and biologics. Thirty-four (71%) patients were still using upadacitinib treatment at last follow up (median duration 46.5 weeks). Fourteen (29%) patients discontinued treatment due to ineffectiveness or AE. Upadacitinib treatment led to a significant decrease of disease severity during a median follow up of 37.5 weeks. Median IGA at baseline decreased from 3 (IQR 2-3) to 1.5 (IQR 1-2) at last review (p < 0.001). Median NRS itch decreased from 7 (IQR 5-8) at baseline to 2.25 (IQR 0.25-6.5) at last review (p < 0.001). Three patients discontinued treatment due to AE. Forty-eight AEs were reported, including acne-like eruptions (25%), nausea (13%) and respiratory tract infections (10%).

CONCLUSIONS

In this real-world cohort, we confirmed that upadacitinib is an effective treatment in a subset of AD patients that have failed several previous systemic immunosuppressive and biologic treatments. Overall, AE were mostly well tolerated and not a reason to discontinue treatment for most patients.

Epigenetic Methylation Changes in Pregnant Women: Bisphenol Exposure and Atopic Dermatitis

Bisphenol is a chemical substance widely used in plastic products and food containers. In this study, we observed a relationship between DNA methylation and atopic dermatitis (AD) in the peripheral blood mononuclear cells (PBMCs) of pregnant women exposed to bisphenol A (BPA) and its alternatives, bisphenol S (BPS) and bisphenol F (BPF). DNA methylation is an epigenetic mechanism that regulates gene expression, which can be altered by environmental factors, and affects the onset and progression of diseases. We found that genes belonging to the JAK-STAT and PI3K-AKT signaling pathways were hypomethylated in the blood of pregnant women exposed to bisphenols. These genes play important roles in skin barrier function and immune responses, and may influence AD. Therefore, we suggest that not only BPA, but also BPS and BPF, which are used as alternatives, can have a negative impact on AD through epigenetic mechanisms.

Adipokines in atopic dermatitis: the link between obesity and atopic dermatitis

Atopic dermatitis (AD) is a chronic skin condition with intense pruritus, eczema, and dry skin. The recurrent intense pruritus and numerous complications in patients with AD can profoundly affect their quality of life. Obesity is one of its comorbidities that has been confirmed to be the hazard factor of AD and also worsen its severity. Nevertheless, the specific mechanisms that explain the connection between obesity and AD remain incompletely recognized. Recent studies have built hopes on various adipokines to explain this connection. Adipokines, which are disturbed by an obese state, may lead to immune system imbalances in people with AD and promote the development of the disease. This review focuses on the abnormal expression patterns of adipokines in patients with AD and their potential regulatory molecular mechanisms associated with AD. The connection between AD and obesity is elucidated through the involvement of adipokines. This conduces to the in-depth exploration of AD pathogenesis and provides a new perspective to develop therapeutic targets.

Celastrol Pyrazine Derivative Alleviates Silicosis Progression via Inducing ROS-Mediated Apoptosis in Activated Fibroblasts

Silicosis is a complex occupational disease without recognized effective treatment. Celastrol, a natural product, has shown antioxidant, anti-inflammatory, and anti-fibrotic activities, but the narrow therapeutic window and high toxicity severely limit its clinical application. Through structural optimization, we have identified a highly efficient and low-toxicity celastrol derivative, CEL-07. In this study, we systematically investigated the therapeutic potential and underlying mechanisms of CEL-07 in silicosis fibrosis. By constructing a silicosis mouse model and analyzing with HE, Masson, Sirius Red, and immunohistochemical staining, CEL-07 significantly prevented the progress of inflammation and fibrosis, and it effectively improved the lung respiratory function of silicosis mice. Additionally, CEL-07 markedly suppressed the expression of inflammatory factors (IL-6, IL-1α, TNF-α, and TNF-β) and fibrotic factors (α-SMA, collagen I, and collagen III), and promoted apoptosis of fibroblasts by increasing ROS accumulation. Moreover, bioinformatics analysis combined with experimental validation revealed that CEL-07 inhibited the pathways associated with inflammation (PI3K-AKT and JAK2-STAT3) and the expression of apoptosis-related proteins. Overall, these results suggest that CEL-07 may serve as a potential candidate for the treatment of silicosis.

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.

Heat shock protein 90 inhibition attenuates inflammation in models of atopic dermatitis: a novel mechanism of action

Background

Heat shock protein 90 (HSP90) is an important chaperone supporting the function of many proinflammatory client proteins. Recent studies indicate HSP90 inhibition may be a novel mechanism of action for inflammatory skin diseases; however, this has not been explored in atopic dermatitis (AD).

Objectives

Our study aimed to investigate HSP90 as a novel target to treat AD.

Methods

Experimental models of AD were used including primary human keratinocytes stimulated with cytokines (TNF/IFNγ or TNF/IL-4) and a mouse model established by MC903 applications.

Results

In primary human keratinocytes using RT-qPCR, the HSP90 inhibitor RGRN-305 strongly suppressed the gene expression of Th1- (TNF, IL1B, IL6) and Th2-associated (CCL17, CCL22, TSLP) cytokines and chemokines related to AD. We next demonstrated that topical and oral RGRN-305 robustly suppressed MC903-induced AD-like inflammation in mice by reducing clinical signs of dermatitis (oedema and erythema) and immune cell infiltration into the skin (T cells, neutrophils, mast cells). Interestingly, topical RGRN-305 exhibited similar or slightly inferior efficacy but less weight loss compared with topical dexamethasone. Furthermore, RNA sequencing of skin biopsies revealed that RGRN-305 attenuated MC903-induced transcriptome alterations, suppressing genes implicated in inflammation including AD-associated cytokines (Il1b, Il4, Il6, Il13), which was confirmed by RT-qPCR. Lastly, we discovered using Western blot that RGRN-305 disrupted JAK-STAT signaling by suppressing the activity of STAT3 and STAT6 in primary human keratinocytes, which was consistent with enrichment analyses from the mouse model.

Conclusion

HSP90 inhibition by RGRN-305 robustly suppressed inflammation in experimental models mimicking AD, proving that HSP90 inhibition may be a novel mechanism of action in treating AD.

Histone deacetylase 3 inhibition alleviates 2,4-dinitrochlorobenzene-induced atopic dermatitis via epigenetically upregulating Nrf2/HO-1 signaling pathway

Atopic dermatitis (AD) is a frequent skin disorder that is associated with immune dysfunction and skin inflammation. Histone deacetylase 3 (HDAC3) possesses strong immune and inflammatory modulatory properties in multiple diseases. However, the role and mechanism of HDAC3 in AD remain unknown. Here, we reported that HDAC3 expression was aberrantly upregulated in 2,4-dinitrochlorobenzene (DNCB)-induced lesional AD skin in mice. Inhibition of HDAC3 by RGFP966 protected against DNCB-induced AD, indicated by improved histological damages, relieved inflammatory and immune dysfunction. Nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) signaling pathway activity in lesional AD skin was significantly decreased and RGFP966 attenuated the decrease. Inhibition of Nrf2/HO-1 signaling pathway via Nrf2 inhibitor ML385 blunted anti-AD effect of RGFP966 in DNCB-treated mice. Mechanistically, RGFP966 promoted Nrf2 expression and upregulated H3K27ac deposition on the promoter region of Nrf2. Collectively, HDAC3 inhibition protects against AD via epigenetically activating Nrf2 transcription to upregulate Nrf2/HO-1 signaling pathway activity. HDAC3 may act as a promising therapeutic target for the treatment of AD.

Characteristics of mucin hypersecretion in different inflammatory patterns based on endotypes of chronic rhinosinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) is usually accompanied by mucin hypersecretion that can lead to mucus accumulation and impair nasal mucociliary clearance, thus exacerbating airway inflammation. Abnormal mucin hypersecretion is regulated by different T helper (Th) cytokines, which are associated with different endotype-driven inflammatory responses. Therefore, it is of great significance to understand how these factors regulate mucin hypersecretion to provide precise treatment strategies for different endotypes of CRS. BODY: Thus far, the most common endotypes of CRS are classified as type 1, type 2, or type 3 immune responses based on innate and adaptive cell-mediated effector immunity, and the representative Th cytokines in these immune responses, such as IFN-γ, TNF-α, IL-4, IL-5, IL-13, IL-10, IL-17, and IL-22, play an important regulatory role in mucin secretion. We reviewed all the related literature in the PubMed database to determine the expression of these Th cytokines in CRS and the role they play in the regulation of mucin secretion.

CONCLUSION

We believe that the main Th cytokines involved in specific endotypes of CRS play a key role in regulating abnormal mucin secretion, which contributes to better understanding of the pathogenesis of CRS and provides therapeutic targets for airway inflammatory diseases associated with mucin hypersecretion.

Upadacitinib: Mechanism of action, clinical, and translational science

Upadacitinib is a selective Janus kinase (JAK) inhibitor which is approved by the US Food and Drug Administration, the European Medicines Agency, as well as other agencies around the world for the treatment of several chronic inflammatory diseases, including rheumatic, dermatologic, and gastrointestinal diseases. Through inhibition of JAK, upadacitinib inhibits phosphorylation of downstream effector proteins, which consequently inhibits cytokine signaling for key pathways involved in inflammatory diseases. Upadacitinib more potently inhibits JAK1 than other JAK isoforms. The pharmacokinetics, pharmacodynamics, efficacy, and safety of upadacitinib were characterized in many clinical trials, which demonstrated the superiority of upadacitinib treatment over placebo or an active comparator in rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, non-radiographic axial spondyloarthritis, atopic dermatitis, Crohn's disease, and ulcerative colitis. The safety profile of upadacitinib supported a favorable benefit-risk profile across all the approved indications. In this article, we review the mechanism of action of upadacitinib and describe how the JAK-STAT (Janus kinase-signal transducers and activators of transcription) pathway is involved in the pathogenesis of several chronic and progressive immune-mediated inflammatory diseases. In addition, this review also provides an overview of key clinical trials that were conducted as well as relevant data which supported the clinical development of upadacitinib and informed the recommended dose(s) in each of the approved indications.

The safety of systemic Janus kinase inhibitors in atopic dermatitis: A systematic review and meta-analysis of randomized controlled trials

Janus kinase (JAK) inhibitors have been recently approved by the FDA and are widely used in the treatment of patients with atopic dermatitis. However, a comprehensive safety profile of JAK inhibitors in patients with atopic dermatitis has not been analysed. This study aimed to establish clinical evidence for the safety of systemic JAK inhibitors in patients with atopic dermatitis. Medline, Embase, Clinicaltrials.gov, Cochrane Central Register of Controlled Trials (CENTRAL) and International Clinical Trials Registry Platform (ICTRP) were considered for search databases. Randomized controlled trials reporting the adverse events of systemic therapy in patients with atopic dermatitis were included. The risk of 11 adverse events was compared between the JAK inhibitors and placebo groups. Fourteen randomized controlled trials were analysed published between 2019 and 2022. The JAK inhibitors included in the analysis were abrocitinib (10, 30, 100 and 200 mg), baricitinib (1, 2 and 4 mg) and upadacitinib (7.5, 15 and 30 mg). The risk of herpes zoster, headache, acne, elevated blood creatinine phosphokinase and nausea was significantly increased, but the risk of serious infection, non-melanoma skin cancer (NMSC), malignancies other than NMSC, major adverse cardiovascular event, venous thromboembolism and nasopharyngitis was not increased. This study provides comprehensive clinical evidence on the risk of various adverse events in patients with atopic dermatitis. However, since the follow-up periods of the studies analysed in this review were mostly limited to 16 weeks or less, it is recommended that comprehensive long-term observational studies be conducted to determine any potential adverse events associated with major cardiovascular events or malignancies, which typically have prolonged courses.

Anti-Inflammatory Effects of the LK5 Herbal Complex on LPS- and IL-4/IL-13-Stimulated HaCaT Cells and a DNCB-Induced Animal Model of Atopic Dermatitis in BALB/c Mice

Atopic dermatitis (AD) is a chronic inflammatory skin disease influenced by a complex interplay of genetic and environmental factors. The activation of the JAK-STAT pathway increases the expression of inflammatory cytokines such as IL-4 and IL-13, further deteriorating AD. Therefore, for the treatment of AD, the JAK-STAT pathway is emerging as a significant target, alongside inflammatory cytokines. This study investigates the potential therapeutic effects of a novel herbal complex, LK5, composed of Scutellaria baicalensis, Liriope platyphylla, Sophora flavescens, Dictammus dasycarpus, and Phellodendron schneider, known for their anti-inflammatory and immune-modulating properties. We examined the anti-inflammatory and anti-AD effects of the LK5 herbal complex in HaCaT cells stimulated by LPS and IL-4/IL-13, as well as in a mouse model of AD induced by DNCB. In HaCaT cells stimulated with LPS or IL-4/IL-13, the LK5 herbal complex demonstrated anti-inflammatory effects by inhibiting the expression of inflammatory cytokines including TNF-α, IL-6, and IL-1β, and downregulating the phosphorylation of STAT proteins. In a murine AD-like model induced by DNCB, administration of the LK5 herbal complex significantly ameliorated clinical symptoms, including dermatitis, ear thickness, and TEWL. Histological analysis revealed a reduction in epidermal thickness and mast cell infiltration. The LK5 herbal complex also inhibited pruritus induced by compound 48/80. Furthermore, the LK5 herbal complex treatment significantly decreased the levels of inflammatory cytokines such as TSLP, IL-6, and IgE in plasma and ear tissue of AD-induced mice. These findings suggest that the LK5 herbal complex may modulate the immune response and alleviate AD symptoms by inhibiting STAT pathways.

The decoy oligodeoxynucleotide against HIF-1α and STAT5 ameliorates atopic dermatitis-like mouse model

Atopic dermatitis (AD) is a common inflammatory skin disease caused by an immune disorder. Mast cells are known to be activated and granulated to maintain an allergic reaction, including rhinitis, asthma, and AD. Although hypoxia-inducible factor-1 alpha (HIF-1α) and signal transducer and activator of transcription 5 (STAT5) play crucial roles in mast cell survival and granulation, their effects need to be clarified in allergic disorders. Thus, we designed decoy oligodeoxynucleotide (ODN) synthetic DNA, without open ends, containing complementary sequences for HIF-1α and STAT5 to suppress the transcriptional activities of HIF-1α and STAT5. In this study, we demonstrated the effects of HIF-1α/STAT5 ODN using AD-like in vivo and in vitro models. The HIF-1α/STAT5 decoy ODN significantly alleviated cutaneous symptoms similar to AD, including morphology changes, immune cell infiltration, skin barrier dysfunction, and inflammatory response. In the AD model, it also inhibited mast cell infiltration and degranulation in skin tissue. These results suggest that the HIF-1α/STAT5 decoy ODN ameliorates the AD-like disorder and immunoglobulin E (IgE)-induced mast cell activation by disrupting HIF-1α/STAT5 signaling pathways. Taken together, these findings suggest the possibility of HIF-1α/STAT5 as therapeutic targets and their decoy ODN as a potential therapeutic tool for AD.

The role and mechanisms of mesenchymal stem cells regulating macrophage plasticity in spinal cord injury

Spinal Cord Injury (SCI) is a devastating neurological disorder comprising primary mechanical injury and secondary inflammatory response-mediated injury for which an effective treatment is still unavailable. It is well known that secondary inflammatory responses are a significant cause of difficulties in neurological recovery. An immune imbalance between M1/M2 macrophages at the sites of injury is involved in developing and progressing the secondary inflammatory response. Recently, Mesenchymal Stem Cells (MSCs) have shown significant therapeutic potential in tissue engineering and regenerative medicine due to their potential multidirectional differentiation and immunomodulatory properties. Accumulating evidence shows that MSCs can regulate the balance of M1/M2 macrophage polarization, suppress downstream inflammatory responses, facilitate tissue repair and regeneration, and improve the prognosis of SCI. This article briefly overviews the impact of macrophages and MSCs on SCI and repair. It discusses the mechanisms by which MSCs regulate macrophage plasticity, including paracrine action, release of exosomes and apoptotic bodies, and metabolic reprogramming. Additionally, the article summarizes the relevant signaling pathways of MSCs that regulate macrophage polarization.

Real-world effectiveness of abrocitinib treatment in patients with difficult-to-treat atopic dermatitis

BACKGROUND

Abrocitinib is a JAK-1 selective inhibitor registered for the treatment of moderate-to-severe atopic dermatitis (AD). Although efficacy and safety have been shown in phase 3 clinical trials, data on real-world patients with a treatment history of advanced systemics are scarce.

OBJECTIVES

The objective of the study was to evaluate the effectiveness and safety of abrocitinib treatment in patients with difficult-to-treat AD in daily practice.

METHODS

In this prospective observational single-centre study, all AD patients who started abrocitinib treatment in the context of standard care between April 2021 and December 2022 were included. Effectiveness was assessed using clinician- and patient-reported outcome measures. Adverse events were evaluated.

RESULTS

Forty-one patients were included. The majority (n = 30; 73.2%) had failed (ineffectiveness) on other targeted therapies, including JAK inhibitors (n = 14, 34%) and biologics (n = 16, 39%). Abrocitinib treatment resulted in a significant decrease in disease severity during a median follow-up period of 25 weeks (IQR 16-34). Median EASI score at baseline decreased from 14.7 (IQR 10.4-25.4) to 4.0 (IQR 1.6-11.4) at last review (p < 0.001). Median NRS itch decreased from 7.0 (IQR 5-8) to 3.0 (IQR 1-2) at last review (p < 0.001). The most frequently reported AEs included gastrointestinal symptoms (27.6%), acne (20.7%) and respiratory tract infections (17.2%). 16 (39%) patients discontinued abrocitinib treatment due to ineffectiveness, AEs or both (41.2%, 41.2% and 11.8%, respectively).

CONCLUSION

Abrocitinib can be an effective treatment for patients with moderate-to-severe AD in daily practice, including non-responders to other targeted therapies.

Molecular mechanisms of pruritus in prurigo nodularis

Pruritus is the most common symptom of dermatological disorders, and prurigo nodularis (PN) is notorious for intractable and severe itching. Conventional treatments often yield disappointing outcomes, significantly affecting patients' quality of life and psychological well-being. The pathogenesis of PN is associated with a self-sustained "itch-scratch" vicious cycle. Recent investigations of PN-related itch have partially revealed the intricate interactions within the cutaneous neuroimmune network; however, the underlying mechanism remains undetermined. Itch mediators play a key role in pruritus amplification in PN and understanding their action mechanism will undoubtedly lead to the development of novel targeted antipruritic agents. In this review, we describe a series of pruritogens and receptors involved in mediating itching in PN, including cytokines, neuropeptides, extracellular matrix proteins, vasculogenic substances, ion channels, and intracellular signaling pathways. Moreover, we provide a prospective outlook on potential therapies based on existing findings.

Helicobacter pylori infection attenuates 2,4-dinitrochlorobenzene-induced atopic dermatitis-like skin lesions in C57/BL6 mice

BACKGROUND

Although numerous studies have suggested a negative correlation between Helicobacter pylori (H. pylori) infection and allergies, there has been limited research on the relationship between H. pylori infections and atopic dermatitis (AD). The present study aimed to investigate the effects of H. pylori infection in an AD mouse model and identify potential mechanisms related to type 2 immunity, skin barrier defects, and pruritus.

METHODS

A model of AD-like symptoms was established with 2,4-dinitrochlorobenzene (DNCB) after infection of the gastric cavity with H. pylori. Analysis of the expression of key inflammatory cytokines and serum levels of immunoglobulin E (IgE) was based on enzyme-linked immunosorbent assay (ELISA). The expression of filaggrin (FLG) and loricrin (LOR) were analyzed by immunohistochemistry staining. The evaluation of STAT1, STAT3, phosphorylated STAT1 (phospho-STAT1), and phosphorylated STAT3 (phospho-STAT1) expression levels in skin lesions was performed using western blot.

RESULTS

The present study showed that the H. pylori-positive AD group (HP+AD+) exhibited milder skin lesions, including erythema, erosion, swelling, and scaling, than the H. pylori-negative AD group (HP-AD+). Additionally, HP+AD+ displayed lower levels of IgE in serum, and downregulated expression of interleukins 4 and 31 (IL-4 and IL-31) in serum. Furthermore, HP+AD+ demonstrated higher expression of filaggrin and loricrin than HP-AD+. Notably, H. pylori significantly reduced the amount of phosphorylated STAT1 and STAT3.

CONCLUSION

Helicobacter pylori infection negatively regulates the inflammatory response by affecting inflammatory factors in the immune response, and repairs the defective epidermal barrier function. In addition, H. pylori infection may reduce IL-31, thereby alleviating pruritus. These effects may be associated with the inhibition of JAK-STAT signaling activation.

Treatment of Netherton syndrome with upadacitinib

We reported the case of a patient with Netherton syndrome (NS) who showed remarkable cutaneous improvement using upadacitinib in the short term, but the efficacy decreased long term. This patient’s case demonstrates that Janus kinase inhibitors have reduced long-term clinical efficacy, which is the same as other biologic therapies used to treat patients with NS. This shows that NS is a complex skin disorder and more studies and clinical trials are required focusing on the long-term efficacy of these drugs.

Nanodrug Delivery Strategies to Signaling Pathways in Alopecia

Over 50% of the global population suffers from hair loss. The mixed results in the treatment of hair loss reveal the limitations of conventional commercial topical drugs. One the one hand, the definite pathogenesis of hair loss is still an enigma. On the other hand, targeted drug carriers ensure the drug therapeutic effect and low side effects. This review highlights the organization and overview of nine crucial signaling pathways associated with hair loss, as well as the development of nanobased topical delivery systems loading the clinical drugs, which will fuel emerging hair loss treatment strategies.

Anti-Atopic Dermatitis Effect of TPS240, a Novel Therapeutic Peptide, via Suppression of NF-κB and STAT3 Activation

Atopic dermatitis (AD) is a relapsing skin disease with persistent inflammation as a causal factor for symptoms and disease progression. Current therapies provide only temporary relief and require long-term usage accompanied by side effects due to persistent relapses. A short peptide, TPS240, has been tested for its potential to subside AD. In this study, we confirmed the anti-atopic effect of TPS240 in vivo and in vitro using a DNCB-induced AD mouse model and TNF-α/IFN-γ-stimulated HaCaT cells. In the AD mouse model, topical treatment with TPS240 diminished AD-like skin lesions and symptoms such as epidermal thickening and mast cell infiltration induced by DNCB, similar to the existing treatment, dexamethasone (Dex). Furthermore, skin atrophy, weight loss, and abnormal organ weight changes observed in the Dex-treated group were not detected in the TPS240-treated group. In TNF-α/IFN-γ-stimulated HaCaT cells, TPS240 reduced the expression of the inflammatory chemokines CCL17 and CCL22 and the pruritic cytokines TSLP and IL-31 by inhibiting NF-κB and STAT3 activation. These results suggest that TPS240 has an anti-atopic effect through immunomodulation of AD-specific cytokines and chemokines and can be used as a candidate drug for the prevention and treatment of AD that can solve the safety problems of existing treatments.

JAK-STAT pathway inhibitors in dermatology

The JAK-STAT signaling pathway mediates important cellular processes such as immune response, carcinogenesis, cell differentiation, division and death. Therefore, drugs that interfere with different JAK-STAT signaling patterns have potential indications for various medical conditions. The main dermatological targets of JAK-STAT pathway inhibitors are inflammatory or autoimmune diseases such as psoriasis, vitiligo, atopic dermatitis and alopecia areata; however, several dermatoses are under investigation to expand this list of indications. As JAK-STAT pathway inhibitors should gradually occupy a relevant space in dermatological prescriptions, this review presents the main available drugs, their immunological effects, and their pharmacological characteristics, related to clinical efficacy and safety, aiming to validate the best dermatological practice.

Type 2 chronic inflammatory diseases: targets, therapies and unmet needs

Over the past two decades, significant progress in understanding of the pathogenesis of type 2 chronic inflammatory diseases has enabled the identification of compounds for more than 20 novel targets, which are approved or at various stages of development, finally facilitating a more targeted approach for the treatment of these disorders. Most of these newly identified pathogenic drivers of type 2 inflammation and their corresponding treatments are related to mast cells, eosinophils, T cells, B cells, epithelial cells and sensory nerves. Epithelial barrier defects and dysbiotic microbiomes represent exciting future drug targets for chronic type 2 inflammatory conditions. Here, we review common targets, current treatments and emerging therapies for the treatment of five major type 2 chronic inflammatory diseases - atopic dermatitis, chronic prurigo, chronic urticaria, asthma and chronic rhinosinusitis with nasal polyps - with a high need for targeted therapies. Unmet needs and future directions in the field are discussed.

Novel Quinazoline Derivative Induces Differentiation of Keratinocytes and Enhances Skin Barrier Functions against Th2 Cytokine-Mediated Signaling

Atopic dermatitis (AD) is a common inflammatory skin disease characterized by pruritic lesions and skin barrier dysfunction. In this study, we evaluated the effect of a quinazoline derivative, SH-340, on TSLP expression and signaling in human primary keratinocytes. Our results demonstrated that SH-340 significantly increased factors for differentiation and skin barrier function including KRT1, KRT2, KRT10, IVL, LOR, CLDN1, OVOL1, and FLG, whereas it inhibited TSLP expression in a dose-dependent manner, both at the mRNA and protein levels. Furthermore, SH-340 was found to inhibit the phosphorylation of STAT6, a downstream signaling molecule of IL-4 and IL-13, in keratinocytes. These findings suggest that SH-340 may suppress TSLP expression by inhibiting the IL-4/IL-13-STAT6 signaling pathway. Finally, SH-340 may potentially contribute to both the alleviation of inflammation and the restoration of skin barrier function.

Novel Therapeutic Strategies in the Treatment of Systemic Sclerosis

Systemic sclerosis is a connective tissue disease of unknown origin and with an unpredictable course, with both cutaneous and internal organ manifestations. Despite the enormous progress in rheumatology and clinical immunology, the background of this disease is largely unknown, and no specific therapy exists. The therapeutic approach aims to treat and preserve the function of internal organs, and this approach is commonly referred to as organ-based treatment. However, in modern times, data from other branches of medicine may offer insight into how to treat disease-related complications, making it possible to find new drugs to treat this disease. In this review, we present therapeutic options aiming to stop the progression of fibrotic processes, restore the aberrant immune response, stop improper signalling from proinflammatory cytokines, and halt the production of disease-related autoantibodies.

Challenges and Future Trends in Atopic Dermatitis

Atopic dermatitis represents a complex and multidimensional interaction that represents potential fields of preventive and therapeutic management. In addition to the treatment armamentarium available for atopic dermatitis, novel drugs targeting significant molecular pathways in atopic dermatitis biologics and small molecules are also being developed given the condition's complex pathophysiology. While most of the patients are expecting better efficacy and long-term control, the response to these drugs would still depend on numerous factors such as complex genotype, diverse environmental triggers and microbiome-derived signals, and, most importantly, dynamic immune responses. This review article highlights the challenges and the recently developed pharmacological agents in atopic dermatitis based on the molecular pathogenesis of this condition, creating a specific therapeutic approach toward a more personalized medicine.

Evolving cognition of the JAK-STAT signaling pathway: autoimmune disorders and cancer

The Janus kinase (JAK) signal transducer and activator of transcription (JAK-STAT) pathway is an evolutionarily conserved mechanism of transmembrane signal transduction that enables cells to communicate with the exterior environment. Various cytokines, interferons, growth factors, and other specific molecules activate JAK-STAT signaling to drive a series of physiological and pathological processes, including proliferation, metabolism, immune response, inflammation, and malignancy. Dysregulated JAK-STAT signaling and related genetic mutations are strongly associated with immune activation and cancer progression. Insights into the structures and functions of the JAK-STAT pathway have led to the development and approval of diverse drugs for the clinical treatment of diseases. Currently, drugs have been developed to mainly target the JAK-STAT pathway and are commonly divided into three subtypes: cytokine or receptor antibodies, JAK inhibitors, and STAT inhibitors. And novel agents also continue to be developed and tested in preclinical and clinical studies. The effectiveness and safety of each kind of drug also warrant further scientific trials before put into being clinical applications. Here, we review the current understanding of the fundamental composition and function of the JAK-STAT signaling pathway. We also discuss advancements in the understanding of JAK-STAT-related pathogenic mechanisms; targeted JAK-STAT therapies for various diseases, especially immune disorders, and cancers; newly developed JAK inhibitors; and current challenges and directions in the field.

Interactions between Malassezia and New Therapeutic Agents in Atopic Dermatitis Affecting Skin Barrier and Inflammation in Recombinant Human Epidermis Model

Several studies have reported the pathogenic role of Malassezia in atopic dermatitis (AD); the significance of Malassezia’s influence on AD needs to be further investigated. Dupilumab, a monoclonal antibody to anti-Interleukin (IL) 4Rα, and ruxolitinib, a Janus kinase (JAK)1/2 inhibitor, are the first approved biologics and inhibitors widely used for AD treatment. In this study, we aimed to investigate how Malassezia Restricta (M. restricta) affects the skin barrier and inflammation in AD and interacts with the AD therapeutic agents ruxolitinib and anti-IL4Rα. To induce an in vitro AD model, a reconstructed human epidermis (RHE) was treated with IL-4 and IL-13. M. restricta was inoculated on the surface of RHE, and anti-IL4Rα or ruxolitinib was supplemented to model treated AD lesions. Histological and molecular analyses were performed. Skin barrier and ceramide-related molecules were downregulated by M. restricta and reverted by anti-IL4Rα and ruxolitinib. Antimicrobial peptides, VEGF, Th2-related, and JAK/STAT pathway molecules were upregulated by M. restricta and suppressed by anti-IL4Rα and ruxolitinib. These findings show that M. restricta aggravated skin barrier function and Th2 inflammation and decreased the efficacy of anti-IL4Rα and ruxolitinib.

Effects of natural products on skin inflammation caused by abnormal hormones secreted by the adrenal gland

The cortex of adrenal gland produces glucocorticoid, mineralocorticoid, and androgen. The medulla of adrenal gland secrets catecholamines. These hormones play an important role in regulating blood pressure, metabolism, and homeostasis of glucose or electrolytes. Hypersecretion or hyposecretion by the adrenal gland will cause a complex cascade of hormone effects and lead to diseases, including Addison's disease, Cushing's syndrome, and congenital adrenal cortical hyperplasia. Skin is the largest organ of body. It provides protection and acts as a barrier against external damage factors like infectious organisms, chemicals, and allergens. Endocrinologic disorders often induce cutaneous abnormalities. According to the previous evidences, natural products have the potential properties for attenuating skin disorders and improving dermatologic symptoms by inhibiting inflammation through MAPK or PI3K/AKT-dependent NF-κB pathways. The natural products may also promote skin wound healing by inhibiting the production of matrix metalloproteinase-9. We systematically searched the relevant articles from databases, including PubMed, Embase, and Cochrane library databases, to review the effects of natural products on skin disorders. This article summarized the effects of natural products on skin inflammation caused by abnormal hormone secreted by adrenal gland. And the published papers indicated that natural products might be a potential source for treating skin diseases.