The hidden sentinel of the skin: An overview on the role of interleukin-13 in atopic dermatitis

Characterization of Inflammatory Mediators and Metabolome in Interstitial Fluid Collected with Dermal Open Flow Microperfusion before and at the End of Dupilumab Treatment in Atopic Dermatitis

Dupilumab is a monoclonal antibody approved for the treatment of atopic dermatitis (AD); however, its effects on molecular, cellular, and immunological levels remain to be elucidated. In this study, blood and dermal interstitial fluid (ISF) from nonlesional (NL) and lesional (L) skin were collected from eight patients with moderate to severe AD, before (visit 2-v2) and at the end of a 16-week treatment with dupilumab (visit 10-v10). Clinical treatment effect was demonstrated by significantly decreased AD severity scores at the end of treatment. At v10 versus v2, the percentages of CD4+ interleukin-producing cells showed a decreasing trend in ISF L and NL, unbound IL-4 levels in plasma were increased, IL-5 levels in ISF L reduced, and levels of factors involved in anti-inflammatory pathways and re-epithelization increased. At v2, ISF L showed that AD lesions might have altered amino acid pathways and lipid signaling compared to ISF NL. At v10, ISF L exhibited raised levels of long- and very-long-chain fatty acids and lipids compared to v2. Furthermore, dupilumab administration caused reduced expression of miR-155-5p and miR-378a-3p in ISF L. In conclusion, results from the present study provided novel knowledge by linking local immune and metabolic alterations to AD pathogenesis and treatment response.

Greater mechanistic understanding of the cutaneous pathogenesis of Stevens-Johnson syndrome/toxic epidermal necrolysis can shed light on novel therapeutic strategies: a comprehensive review

PURPOSE OF REVIEW

Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) are severe cutaneous adverse drug reactions (SCARs) characterized by widespread epithelial detachment and blistering, which affects the skin and mucocutaneous membranes. To date, therapeutic interventions for SJS/TEN have focused on systematic suppression of the inflammatory response using high-dose corticosteroids or intravenous immunoglobulin G (IgG), for example. No targeted therapies for SJS/TEN currently exist.

RECENT FINDINGS

Though our understanding of the pathogenesis of SJS/TEN has advanced from both an immunological and dermatological perspective, this knowledge is yet to translate into the development of new targeted therapies.

SUMMARY

Greater mechanistic insight into SJS/TEN would potentially unlock new opportunities for identifying or repurposing targeted therapies to limit or even prevent epidermal injury and blistering.

LncRNA microarray profiling identifies novel circulating lncRNAs in hidradenitis suppurativa

Long noncoding RNAs (lncRNAs) have been demonstrated to be involved in biological processes, both physiological and pathological, including cancer, cardiovascular diseases, multiple sclerosis, autoimmune hepatitis and types I and II diabetes. LncRNAs are also known to have a critical role in the physiology of skin, and in the pathology of cutaneous diseases. LncRNAs are involved in a wide range of biological activities, including transcriptional post‑transcriptional processes, epigenetics, RNA splicing, gene activation and or silencing, modifications and/or editing; therefore, lncRNAs may be useful as potential targets for disease treatment. Hidradenitis suppurativa (HS), also termed acne inversa, is a major skin disease, being an inflammatory disorder that affects ~1% of global population in a chronic manner. Its pathogenesis, however, is only partly understood, although immune dysregulation is known to have an important role. To investigate the biological relevance of lncRNAs with HS, the most differentially expressed lncRNAs and mRNAs were first compared. Furthermore, the lncRNA‑microRNA regulatory network was also defined via reverse transcription‑quantitative PCR analysis, whereby a trio of lncRNA expression signatures, lncRNA‑TINCR, lncRNA‑RBM5‑ASI1 and lncRNA‑MRPL23‑AS1, were found to be significantly overexpressed in patients with HS compared with healthy controls. In conclusion, the three lncRNAs isolated in the present study may be useful for improving the prognostic prediction of HS, as well as contributing towards an improved understanding of the underlying pathogenic mechanisms, thereby potentially providing new therapeutic targets.

Cheungsam Seed Husk Extract Reduces Skin Inflammation through Regulation of Inflammatory Mediator in TNF-α/IFN-γ-Induced HaCaT Cells

Cannabis contains numerous natural components and has several effects such as anticancer, anti-inflammatory and antioxidant. Cheungsam is a variety of non-drug-type hemp, developed in Korea and is used for fiber (stem) and oil (seed). The efficacy of Cheungsam on skin is not yet known, and although there are previous studies on Cheungsam seed oil, there are no studies on Cheungsam seed husk. In this study, we investigated the potential of Cheungsam seed husk ethanol extract (CSSH) to alleviate skin inflammation through evaluating the gene and protein expression levels of inflammatory mediators. The results showed that CSSH reduced pro-inflammatory cytokines (IL-1β, IL-6, IL-8, MCP-1 and CXCL10) and atopic dermatitis-related cytokines (IL-4, CCL17, MDC and RANTES) in TNF-α/IFN-γ-induced HaCaT cells. Furthermore, ERK, JNK and p38 phosphorylation were decreased and p-p65, p-IκBα, NLRP3, caspase-1, p-JAK1 and p-STAT6 were suppressed after CSSH treatment. CSSH significantly increased the level of the skin barrier factors filaggrin and involucrin. These results suggest that Cheungsam seed husk ethanol extract regulates the mechanism of skin inflammation and can be used as a new treatment for skin inflammatory diseases.

Skin, gut, and lung barrier: Physiological interface and target of intervention for preventing and treating allergic diseases

The epithelial barriers of the skin, gut, and respiratory tract are critical interfaces between the environment and the host, and they orchestrate both homeostatic and pathogenic immune responses. The mechanisms underlying epithelial barrier dysfunction in allergic and inflammatory conditions, such as atopic dermatitis, food allergy, eosinophilic oesophagitis, allergic rhinitis, chronic rhinosinusitis, and asthma, are complex and influenced by the exposome, microbiome, individual genetics, and epigenetics. Here, we review the role of the epithelial barriers of the skin, digestive tract, and airways in maintaining homeostasis, how they influence the occurrence and progression of allergic and inflammatory conditions, how current treatments target the epithelium to improve symptoms of these disorders, and what the unmet needs are in the identification and treatment of epithelial disorders.

MRGPRX2 antagonist GE1111 attenuated DNFB-induced atopic dermatitis in mice by reducing inflammatory cytokines and restoring skin integrity

Introduction

Atopic dermatitis (AD) is a chronic inflammatory skin disorder characterised by itching, erythema, and epidermal barrier dysfunction. The pathogenesis of AD is complex and multifactorial; however,mast cell (MC) activation has been reported to be one of the crucial mechanisms in the pathogenesis of AD. The MC receptor Mas related G protein-coupled receptor-X2 (MRGPRX2) has been identified as a prominent alternative receptor to the IgE receptor in causing MC activation and the subsequent release of inflammatory mediators. The current study aimed to evaluate the therapeutic effect of a novel small molecule MRGPRX2 antagonist GE1111 in AD using in vitro and in vivo approaches.

Methods

We developed an in vitro cell culture disease model by using LAD-2 MC, HaCaT keratinocytes and RAW 264.7 macrophage cell lines. We challenged keratinocytes and macrophage cells with CST-14 treated MC supernatant in the presence and absence of GE1111 and measured the expression of tight junction protein claudin 1, inflammatory cytokines and macrophage phagocytosis activity through immunohistochemistry, western blotting, RT-qPCR and fluorescence imaging techniques. In addition to this, we developed a DFNB-induced AD model in mice and evaluated the protective effect and underlying mechanism of GE1111.

Results and Discussion

Our in vitro findings demonstrated a potential therapeutic effect of GE1111, which inhibits the expression of TSLP, IL-13, MCP-1, TNF-a, and IL-1ß in MC and keratinocytes. In addition to this, GE1111 was able to preserve the expression of claudin 1 in keratinocytes and the phagocytotic activity of macrophage cells. The in vivo results demonstrated that GE1111 treatment significantly reduced phenotypic changes associated with AD (skin thickening, scaling, erythema and epidermal thickness). Furthermore, immunohistochemical analysis demonstrated that GE1111 treatment preserved the expression of the tight junction protein Involucrin and reduced the expression of the inflammatory mediator periostin in the mouse model of AD. These findings were supported by gene and protein expression analysis, where GE1111 treatment reduced the expression of TSLP, IL-13, and IL-1ß, as well as downstream signalling pathways of MRGPRX2 in AD skin lesions. In conclusion, our findings provide compelling in vitro and in vivo evidence supporting the contribution of MRGPRX2-MC interaction with keratinocytes and macrophages in the pathogenesis of AD.

Effects of Psychological Stress on Spontaneous Itch and Mechanical Alloknesis of Atopic Dermatitis

Atopic dermatitis (AD), a chronic inflammatory skin disease, manifests as an intractable itch. Psychological stress has been suggested to play a role in the onset and worsening of AD symptoms. However, the pathophysiological relationships between psychological stressors and cutaneous manifestations remain unclear. To elucidate the mechanisms underlying the stress-related exacerbation of itch, we investigated the effects of water stress, restraint stress and repeated social defeat stress on itch-related scratching behaviour, mechanical alloknesis and dermatitis in male NC/Nga mice with AD-like symptoms induced by the repeated application of ointment containing Dermatophagoides farina body. NC/Nga mice with AD-like symptoms were subjected to water stress, restraint stress and repeated social defeat stress, and their scratching behaviour, sensitivity to mechanical stimuli (mechanical alloknesis) and severity of  dermatitis were evaluated. Social defeat stress+ Dermatophagoides farina body-treated mice exposed to stress showed slower improvements in or the exacerbation of AD-like symptoms, including dermatitis and itch. In the mechanical alloknesis assay, the mechanical alloknesis scores of social defeat stress+ Dermatophagoides farina body-treated mice exposed to stress were significantly higher than those of non-exposed social defeat stress+ Dermatophagoides farina body- and social defeat stress-treated mice. These results suggest that psychological stress delays improvements in dermatitis by exacerbating itch hypersensitivity in AD.

A critical evaluation of suitability of tralokinumab for treatment of moderate-to-severe atopic dermatitis in adolescents and adults

INTRODUCTION

Atopic dermatitis (AD) is a chronic, intensely pruritic disease associated with significant patient burden. Recent advancements in AD pathogenesis have expanded its therapeutics pipeline. Tralokinumab is a fully human monoclonal antibody that binds specifically Interleukin (IL)-13, inhibiting the downstream IL-13 signaling. Phase 3 clinical trials and some real-world studies showed that tralokinumab, as monotherapy or in combination with topical corticosteroids, is efficacious and safe in adult patients with moderate-to-severe AD. Similar results were reported in a phase 3 trial in adolescents (aged ≥12 years).

AREAS COVERED

We review the role of IL-13 in AD and discuss the value of tralokinumab for treating moderate-to-severe AD, comparing efficacy and safety results derived from clinical trials and real-life data.

EXPERT OPINION

The role of IL-13 in AD supports a targeted therapeutic approach. Tralokinumab has proven efficacious and well-tolerated in a large proportion of patients confirming its value for treating moderate-to-severe AD from age 12 years onwards; it quickly improves itching and can maintain a high-level of response over time; it can be administered with flexible dosing schedules. Future studies will further clarify the role of IL-13 pathway and which patients would be best suited to tralokinumab, shifting AD treatment into an era of precision medicine.

Airways Type-2 Related Disorders: Multiorgan, Systemic or Syndemic Disease?

Chronic rhinosinusitis (CRS) has recently undergone a significant paradigm shift, moving from a phenotypical classification towards an "endotype-based" definition that places more emphasis on clinical and therapeutic aspects. Similar to other airway diseases, like asthma, most cases of CRS in developed countries exhibit a dysregulated type-2 immune response and related cytokines. Consequently, the traditional distinction between upper and lower airways has been replaced by a "united airway" perspective. Additionally, type-2 related disorders extend beyond respiratory boundaries, encompassing conditions beyond the airways, such as atopic dermatitis. This necessitates a multidisciplinary approach. Moreover, consideration of possible systemic implications is crucial, particularly in relation to sleep-related breathing diseases like Obstructive Sleep Apnoea Syndrome (OSAS) and the alteration of systemic inflammatory mediators such as nitric oxide. The trends in epidemiological, economic, and social burden are progressively increasing worldwide, indicating syndemic characteristics. In light of these insights, this narrative review aims to present the latest evidence on respiratory type-2 related disorders, with a specific focus on CRS while promoting a comprehensive perspective on the "united airways". It also introduces a novel concept: viewing these conditions as a multiorgan, systemic, and syndemic disease.

Skin infections during dupilumab monotherapy in moderate-to-severe atopic dermatitis - a meta-analysis of randomized clinical trials

OBJECTIVE

Atopic dermatitis (AD) increases the risk of bacterial and viral cutaneous infections. This study assesses the risk of skin infections related to dupilumab monotherapy in moderate-to-severe AD.

METHODS

We searched PubMed/Medline, Embase, Web of Science, ClinicalTrials.gov, and Cochrane Library. For gray literature, Google Scholar was searched. A meta-analysis of randomized clinical trials (RCTs) for overall skin infections, eczema herpeticum, nonherpetic skin infections and subgroup meta-analysis based on overall herpetic infection type was performed.

RESULTS

We observed a statistically significant (p < 0.005) lower incidence rate in the dupilumab group compared to placebo for overall skin infections (Risk Ratio [RR] = 0.59, 95% confidence interval [CI]: [0.47, 0.75], P < 0.0001) and nonherpetic skin infections (RR = 0.42, 95% CI: [0.27, 0.66], P = 0.0001). For herpetic infections in 2b phase studies a meta-analysis demonstrated significantly higher events in dupilumab group compared to placebo (RR = 3.38, 95% CI: [1.98, 5.76], P < 0.00001, test for subgroup differences: P = 0.02, I2 = 65.6%).

CONCLUSIONS

In moderate-to-severe AD, dupilumab in monotherapy may be an effective and safe therapeutic approach, not associated with an increased risk of overall skin infections and nonherpetic skin infections. Due to the lack of statistical significance in heterogeneity associated with potential confounders in some cases, results should be interpreted cautiously.

REGISTRATION

The meta-analysis was registered in PROSPERO, ID: CRD42023441346.

Gene signature from cutaneous autoimmune diseases provides potential immunotherapy-relevant biomarkers in melanoma

Immune checkpoint inhibitors (ICIs) are promising agents for treating melanoma. Given that autoimmune skin diseases exhibit hyper immune reaction, investigation of immune cells from autoimmune skin disease is crucial to validate the effectiveness of ICIs in melanoma treatment. We employed multipanel markers to predict the response to immune checkpoint inhibitors by characterizing the gene expression signatures of skin immune cells in systemic lupus erythematosus (SLE), atopic dermatitis (AD), and psoriasis (PS). By analyzing single-cell RNA sequencing data from each dataset, T cell gene signatures from autoimmune skin diseases exhibit a complex immune response in tumors that responded to immunotherapy. Based on that CD86 and CD80 provide essential costimulatory signals for T cell activation, we observed that interaction of CD86 signaling has been enhanced in the T cells of patients with SLE, AD, and PS. Our analysis revealed a common increase in CD86 signals from dendritic cells (DCs) to T cells in patients with SLE, AD, and PS, confirming that dendritic cells produce pro-inflammatory cytokines to activate T cells. Thus, we hypothesize that T cell gene signatures from autoimmune skin diseases exhibit a pro-inflammatory response and have the potential to predict cancer immunotherapy. Our study demonstrated that T cell gene signatures derived from inflammatory skin diseases, particularly SLE and PS, hold promise as potential biomarkers for predicting the response to immune checkpoint blockade therapy in patients with melanoma. Our data provide an understanding of the immune-related characteristics and differential gene expression patterns in autoimmune skin diseases, which may represent promising targets for melanoma immunotherapy.