Activation of mast cells mediates inflammatory response in psoriasis: Potential new therapeutic approach with IL‐37

Cytokines in psoriasis: From pathogenesis to targeted therapy

Psoriasis is a multifactorial disease that affects 0.84% of the global population and it can be associated with disabling comorbidities. As patients present with thick scaly lesions, psoriasis was long believed to be a disorder of keratinocytes. Psoriasis is now understood to be the outcome of the interaction between immunological and environmental factors in individuals with genetic predisposition. While it was initially thought to be solely mediated by cytokines of type-1 immunity, namely interferon-γ, interleukin-2, and interleukin-12 because it responds very well to cyclosporine, a reversible IL-2 inhibitor; the discovery of Th-17 cells advanced the understanding of the disease and helped the development of biological therapy. This article aims to provide a comprehensive review of the role of cytokines in psoriasis, highlighting areas of controversy and identifying the connection between cytokine imbalance and disease manifestations. It also presents the approved targeted treatments for psoriasis and those currently under investigation.

Construction and validation of m6A-related diagnostic model for psoriasis

Background

Psoriasis is a chronic immune-mediated inflammatory disease. N6-methyladenosine (m6A) is involved in numerous biological processes in both normal and diseased states. Herein, we aimed to explore the potential role of m6A regulators in the diagnosis of psoriasis and predict molecular mechanisms by which m6A regulators impact psoriasis.

Methods

GSE30999 (170 human skin tissue samples) and GSE13355 (180 human skin tissue samples) were downloaded as the training analysis dataset and validation dataset respectively. M6A-related genes were obtained from the literature and their expression levels in GSE30999 samples were measured to identify M6A-related DEGs between psoriasis lesions (LS) and non-lesional lesions (NL). We identified m6A-related DEGs using differential expression analysis and assessed their interactions through correlation analysis and network construction. A logistic regression analysis followed by LASSO optimization was employed to select m6A-related DEGs for the construction of a diagnostic model. The performance of the model was validated using support vector machine (SVM) methodology with sigmoid kernel function and extensive cross-validation. Additionally, the correlation between m6A-related DEGs and immune cell infiltration was analyzed, as well as the association of these DEGs with psoriasis subtypes. Functional analysis of the m6A-related DEGs included the construction of regulatory networks involving miRNAs, transcription factors (TFs), and small-molecule drugs. The m6A modification patterns were also explored by examining the gene expression differences between psoriasis subtypes and their enriched biological pathways. Finally, the expression of significant m6A regulators involved in the diagnostic model was examined by RT-qPCR.

Results

In this study, ten optimal m6A-related DEGs were identified, including FTO, IGF2BP2, METTL3, YTHDC1, ZC3H13, HNRNPC, IGF2BP3, LRPPRC, YTHDC2, and HNRNPA2B1. A diagnostic model based on these m6A-related DEGs was constructed, demonstrating high diagnostic accuracy with an area under the curve (AUC) in GSE30999 and GSE13355 of 0.974 and 0.730, respectively. Meanwhile, the expression level of m6A regulators verified by RT-qPCR was consistent with the results in GSE30999. The infiltration of activated mast cells and NK cells was significantly associated with all ten m6A-related DEGs in psoriasis. Among them, YTHDC1, HNRNPC, and FTO were targeted by most miRNAs and were regulated by nine related TFs. Therefore, patients may benefit from dorsomorphin and cyclosporine therapy. Between the two subgroups, 1,592 DEGs were identified, including LRPPRC and METTL3. These DEGs were predicted to be involved in neutrophil activation, cytokine-cytokine receptor interactions, and chemokine signaling pathways.

Conclusions

A diagnostic model based on ten m6A-related DEGs in patients with psoriasis was constructed, which may provide early diagnostic biomarkers and therapeutic targets for psoriasis.

Efficient Loading and Sustained Delivery of Methotrexate Using a Tip-Swellable Microneedle Array Patch for Psoriasis Treatment

Methotrexate (MTX), a primary treatment for moderate to severe psoriasis, is limited in clinical use due to suboptimal results and severe side effects from subcutaneous (SC) injection and oral administration. Microneedles offer a promising alternative for direct MTX delivery to targeted skin lesions, but issues such as drug wastage, dosage inaccuracy, and limited drug residence time in the lesions remain. This study introduces a tip-swellable microneedle array patch (TSMAP) using photo-cross-linked methacrylated hyaluronic acid (MeHA) and biocompatible resin for effective MTX loading and sustained delivery. A two-cast micromolding with vacuum drying is employed to concentrate cross-linked MeHA in about 30% of the needle's height at the tip, thereby ensuring that only the TSMAP tip swells. Efficient MTX loading into TSMAP tips is achieved through a 30 s drug solution immersion and 10 min drying, potentially minimizing drug waste from incomplete skin insertion due to skin elasticity. The MTX-loaded TSMAP effectively penetrates both porcine and psoriasis-like mouse skin with its tips detaching from the resin substrate and embedding deeply into the skin tissue, thereby functioning as a drug release reservoir. TSMAP significantly prolongs drug retention in skin compared with SC injection and dissolvable microneedles. The in vivo study demonstrates that TSMAP-mediated MTX delivery substantially enhances therapeutic outcomes in alleviating psoriasis symptoms and downregulating psoriasis-associated cytokines, outperforming oral administration, SC injection, and dissolvable microneedles. Thus, TSMAP could offer an efficient and user-friendly alternative for drug administration in the treatment of various skin diseases.

Interleukin-37 inhibits desmoglein-3 endocytosis and keratinocyte dissociation via upregulation of Caveolin-1 and inhibition of the STAT3 pathway

BACKGROUND

Pemphigus vulgaris (PV) is a potentially fatal autoimmune bullous disease primarily caused by acantholysis of keratinocytes attributed to pathogenic desmoglein-3 (Dsg3) autoantibodies. Interleukin-37 (IL-37) reportedly plays important roles in a variety of autoimmune diseases, but its role in PV is not clear.

OBJECTIVES

To investigate whether IL-37 plays a role in the occurrence and progression of PV.

METHODS

HaCaT keratinocytes were stimulated with anti-Dsg3 antibody to establish an in vitro PV model, which was defined as anti-Dsg3 group. Cells incubated with medium without anti-Dsg3 treatment were used as control. IL-37 was cultured with these cells infected with or without lentiviral vector shRNA-Caveolin-1 (sh-Cav-1-LV). Cell dissociation assay and immunocytofluorescence were performed to assess keratinocyte dissociation, keratin retraction and Dsg3 endocytosis. Real-time PCR was used to detect the mRNA level of Cav-1, and western blot was used to determine the protein expression of Cav-1, Dsg3, STAT3 and phosphorylated-STAT3 (p-STAT3).

RESULTS

The anti-Dsg3 group showed more cell debris, increased keratin retraction, increased Dsg3 endocytosis, reduced Cav-1 expression and co-localization than the control group, while IL-37 treatment neutralized all of these changes. Interestingly, Cav-1 knockdown supressed the inhibitory effect of IL-37 on keratinocyte dissociation and Dsg3 internalization. The protein expression of p-STAT3 was increased in keratinocytes of the PV model but decreased by IL-37. Re-activation of the STAT3 pathway by colivelin supressed the inhibitory effect of IL-37 on keratinocyte dissociation and Dsg3 internalization, along with upregulation of Cav-1 and Dsg3.

CONCLUSIONS

IL-37 inhibited keratinocyte dissociation and Dsg3 endocytosis in an in vitro PV model through the upregulating Cav-1 and inhibiting STAT3 pathway.

IL-33 and IL-37: A Possible Axis in Skin and Allergic Diseases

Interleukin (IL)-37 and IL-33 are among the latest cytokines identified, playing a role in several inflammatory conditions, spanning from systemic conditions to tumors to localized diseases. As newly discovered interleukins, their role is still scarcely understood, but their potential role as therapeutic targets or disease activity markers suggests the need to reorganize the current data for a better interpretation. The aim of this review is to collect and organize data produced by several studies to create a complete picture. The research was conducted on the PubMed database, and the resulting articles were sorted by title, abstract, English language, and content. Several studies have been assessed, mostly related to atopic dermatitis and immunologic pathways. Collective data demonstrates a pro-inflammatory role of IL-33 and an anti-inflammatory one for IL-37, possibly related to each other in an IL-33/IL-37 axis. Although further studies are needed to assess the safety and plausibility of targeting these two interleukins for patients affected by skin conditions, the early results indicate that both IL-33 and IL-37 represent markers of disease activity.

Serum immunoglobulin E and Interleukin-17 levels in patients with chronic plaque psoriasis: A case-control study

BACKGROUND

Psoriasis is a skin disorder mainly mediated by T helper (Th)-1 and Th-17 cells. Recently, high serum immunoglobulin (Ig)-E levels were detected in psoriatic patients. The etiopathogenesis of IgE overproduction in psoriatic patients is still unknown, but IL-17 has been suggested to be responsible for this abnormality.

OBJECTIVE

To compare levels of IgE and IL-17 in the sera of patients with chronic plaque psoriasis (CPP) to healthy subjects.

METHODS

This study included 40 patients with CPP and 40 age- and sex-matched healthy individuals. Serum IgE and IL-17 concentrations were measured using the enzyme-linked immunosorbent assay (ELISA) technique.

RESULTS

Levels of IgE and IL-17 were significantly higher in the sera of psoriatic patients than in controls (p = 0.001 and 0.024, respectively). Psoriatic patients with abnormally high serum IgE levels had higher serum IL-17 levels than those with normal serum IgE levels, but the difference was statistically insignificant (p = 0.080). Furthermore, no significant correlation was found between serum IgE and IL-17 concentrations in psoriatic patients (p = 0.385).

CONCLUSIONS

It is possible that IgE and IL-17 interact in psoriasis pathogenesis; however, this was not evident in the current study, possibly due to the small sample size. Therefore, other potential causes of elevated IgE levels in psoriatic patients should be investigated. Moreover, the interaction between IgE and IL-17 should be investigated in patients with other clinical variants of psoriasis.

Psychological Stress, Mast Cells, and Psoriasis-Is There Any Relationship?

Psoriasis vulgaris is a common inflammatory skin disease with still unknown pathogenesis. In recent years, genetic and environmental factors have been mentioned as the main causes. Among environmental factors, many researchers are trying to investigate the role of mental health and its importance in the development of many diseases. In the pathophysiology of psoriasis, the role of the interaction between the nervous, endocrine, and immune systems are often emphasized. So far, no one has clearly indicated where the pathological process begins. One of the hypotheses is that chronic stress influences the formation of hormonal changes (lowering the systemic cortisol level), which favors the processes of autoimmunity. In inflammatory skin conditions, mast cells (MCs) are localized close to blood vessels and peripheral nerves, where they probably play an important role in the response to environmental stimuli and emotional stress. They are usually connected with a fast immune response, not only in allergies but also a protective response to microbial antigens. Among many cells of the immune system, MCs have receptors for the hormones of the hypothalamic-pituitary-adrenal (HPA) axis on their surface. In this review, we will try to take a closer look at the role of MCs in the pathophysiology of psoriasis. This knowledge may give the opportunity to search for therapeutic solutions.

The 5-HT1A receptor agonist, 8-OH-DPAT, attenuates long-lasting pain in imiquimod-induced psoriasis in mice

Psoriasis pain is a common symptom underestimated and rarely evaluated in psoriasis clinical trials. This work aimed to investigate whether the development of secondary chronic allodynia and hyperalgesia in the imiquimod (IMQ)-induced psoriasis mice model could be modulated by anti-inflammatory agents and compound 48/80 (C48/80) and to determine whether the activation of 5-HT_1A receptor modulates these nociceptive behaviours. C57BL/6 male mice were treated with 5% IMQ for 7 days. The paw withdrawal responses to von Frey filaments (10 and 250 mN) were used to assess the allodynia and hyperalgesia. Nociceptive behaviours were also evaluated using ketorolac 15 mg/kg s.c., adalimumab 10 mg/kg s.c. and C48/80 10 mg/kg i.p. Then, the serum serotonin and the impact of 8-OH-DPAT (1 mg/kg s.c), a 5-HT_1A receptor agonist, on long-lasting pain were examined. Mice receiving IMQ showed enhanced nociception, which decreased with all tested compounds. The serum serotonin in the IMQ group showed a significant decrease (947.042 ng/ml) regarding the control group (1143.68 ng/ml). The pretreatment with 8-OH-DPAT alleviated pain-related behaviours. These results suggest that the long-lasting pain resulting from psoriasis inflammation is also associated with the serotonergic system. The 5-HT1A receptor should be further explored as a potential therapeutic target for psoriasis pain modulation.

Mast Cell Cytokines IL-1, IL-33, and IL-36 Mediate Skin Inflammation in Psoriasis: A Novel Therapeutic Approach with the Anti-Inflammatory Cytokines IL-37, IL-38, and IL-1Ra

Psoriasis (PS) is a skin disease with autoimmune features mediated by immune cells, which typically presents inflammatory erythematous plaques, and is associated with many comorbidities. PS exhibits excessive keratinocyte proliferation, and a high number of immune cells, including macrophages, neutrophils, Th1 and Th17 lymphocytes, and mast cells (MCs). MCs are of hematopoietic origin, derived from bone marrow cells, which migrate, mature, and reside in vascularized tissues. They can be activated by antigen-provoking overexpression of proinflammatory cytokines, and release a number of mediators including interleukin (IL)-1 and IL-33. IL-1, released by activated keratinocytes and MCs, stimulates skin macrophages to release IL-36—a powerful proinflammatory IL-1 family member. IL-36 mediates both innate and adaptive immunity, including chronic proinflammatory diseases such as psoriasis. Suppression of IL-36 could result in a dramatic improvement in the treatment of psoriasis. IL-36 is inhibited by IL-36Ra, which binds to IL-36 receptor ligands, but suppression can also occur by binding IL-38 to the IL-36 receptor (IL-36R). IL-38 specifically binds only to IL-36R, and inhibits human mononuclear cells stimulated with IL-36 in vitro, sharing the effect with IL-36Ra. Here, we report that inflammation in psoriasis is mediated by IL-1 generated by MCs—a process that activates macrophages to secrete proinflammatory IL-36 inhibited by IL-38. IL-37 belongs to the IL-1 family, and broadly suppresses innate inflammation via IL-1 inhibition. IL-37, in murine models of inflammatory arthritis, causes the suppression of joint inflammation through the inhibition of IL-1. Therefore, it is pertinent to think that IL-37 can play an inhibitory role in inflammatory psoriasis. In this article, we confirm that IL-38 and IL-37 cytokines emerge as inhibitors of inflammation in psoriasis, and hold promise as an innovative therapeutic tool.

The Psoriatic Nonlesional Skin: A Battlefield between Susceptibility and Protective Factors

In the last two decades, large-scale gene-expression studies on psoriatic skin samples revealed that even though nonlesional skin is macroscopically identical to healthy skin, it harbors several molecular differences. Originally, these molecular differences were thought to represent susceptibility factors for plaque formation. However, we review in this paper the several factors of immune regulation and structural alteration that are specific for the nonlesional skin and serve as protective factors by counteracting plaque formation and contributing to the maintenance of the nonlesional phenotype.

Mast Cells in the Skin: Defenders of Integrity or Offenders in Inflammation?

Mast cells (MCs) are best-known as key effector cells of immediate-type allergic reactions that may even culminate in life-threatening anaphylactic shock syndromes. However, strategically positioned at the host–environment interfaces and equipped with a plethora of receptors, MCs also play an important role in the first-line defense against pathogens. Their main characteristic, the huge amount of preformed proinflammatory mediators embedded in secretory granules, allows for a rapid response and initiation of further immune effector cell recruitment. The same mechanism, however, may account for detrimental overshooting responses. MCs are not only detrimental in MC-driven diseases but also responsible for disease exacerbation in other inflammatory disorders. Focusing on the skin as the largest immune organ, we herein review both beneficial and detrimental functions of skin MCs, from skin barrier integrity via host defense mechanisms to MC-driven inflammatory skin disorders. Moreover, we emphasize the importance of IgE-independent pathways of MC activation and their role in sustained chronic skin inflammation and disease exacerbation.

Mast Cells as a Double Edged Sword in Immunity: Disorders of Mast Cell Activation and Therapeutic Management. Second of Two Parts

Mast cells (MCs) bear many receptors that allow them to respond to a variety of exogenous and endogenous stimuli. However, MC function is dual since they can initiate pathological events or protect the host against infectious challenges. The role of MCs in disease will be analyzed in a broad sense, describing cellular and molecular mechanisms related to their involvement in auto-inflammatory diseases, asthma, autoimmune diseases and cancer. On the other hand, their protective role in the course of bacterial, fungal and parasitic infections will also be illustrated. As far as treatment of MC-derived diseases is concerned, allergen immunotherapy as well as other attempts to reduce MC-activation will be outlined according to the recent data. Finally, in agreement with current literature and our own data polyphenols have been demonstrated to attenuate type I allergic reactions and contact dermatitis in response to nickel. The use of polyphenols in these diseases will be discussed also in view of MC involvement.

Elevated serum levels of interleukin-37 correlate with poor prognosis in gastric cancer

BACKGROUND

interleukin-37 (IL-37) is as a natural suppressor of the innate inflammatory and immune responses. It has also been reported to be involved in carcinogenesis and metastasis. The present case-control study was designed to investigate the role of serum levels of IL-37 in patients with gastric cancer.

METHODS

serum IL-37 levels were determined using the enzyme-linked immunosorbent assay in 180 patients diagnosed with gastric cancer and 100 healthy controls. The association between IL-37 levels and clinical factors was assessed. Univariate and multivariate analyses were performed to investigate the prognostic significance of these parameters in gastric cancer.

RESULTS

serum IL-37 levels in gastric cancer patients (5.606 ± 0.837 pg/ml) were significantly higher than those in healthy controls (2.364 ± 0.210 pg/ml, p < 0.001). High serum IL-37 levels were related to a poorly differentiated histologic type (p = 0.046) and advanced T stage (p = 0.003). The Kaplan-Meier survival analysis indicated that the high-IL-37 group had a poorer overall survival and progression-free survival (overall survival [OS]: 39.0 months vs 13.0 months, p < 0.001, progression-free survival [PFS]: 25.0 months vs 10.0 months, p < 0.001). Multivariate analyses showed serum IL-37 to be an independent prognostic factor for gastric cancer patients (OS: hazard ratios [HR] = 1.842, 95% CI: 1.190-2.854, p = 0.006; PFS: HR = 1.547, 95% CI: 1.014-2.359, p = 0.043).

CONCLUSIONS

in conclusion, serum IL-37 levels were associated with poor overall survival and progression-free survival in gastric cancer patients. IL-37 may be a potential predictor of prognosis in gastric cancer.

The Mast Cell-SCF-CB1 Interaction Is a Key Player in Seborrheic Keratosis

Mast cell (MC) is an important player in the development of skin diseases, including atopic dermatitis, psoriasis, and urticaria. It is reported that MC infiltration and activation are observed around various types of tumors and speculated that MCs play key roles in their pathogenesis. As MCs in human seborrheic keratosis (SK) have not been well investigated, here we focused on the MCs in SK. The number of c-Kit and tryptase-positive MCs was significantly increased around the SK compared with the marginal lesion. Degranulated MCs were also increased around the tumors. Furthermore, MC growth factor, stem cell factor (SCF), expression within the SK was significantly upregulated compared with the marginal lesion. Interestingly, one of the cognitive regulators of SCF expression, cannabinoid receptor type 1 (CB1) immunoreactivity was downregulated within the SK. Our results suggest that MCs play important roles in the pathogenesis of SK and that SCF can be also deeply involved in the development of SKs. Our current results highlight the CB1-SCF-MC interaction as a novel mechanism of SK development and this also will be utilized for developing a novel treatment.

Pathogenesis of psoriasis in the "omic" era. Part I. Epidemiology, clinical manifestation, immunological and neuroendocrine disturbances

Psoriasis is a common, chronic, inflammatory, immune-mediated skin disease affecting about 2% of the world's population. According to current knowledge, psoriasis is a complex disease that involves various genes and environmental factors, such as stress, injuries, infections and certain medications. The chronic inflammation of psoriasis lesions develops upon epidermal infiltration, activation, and expansion of type 1 and type 17 Th cells. Despite the enormous progress in understanding the mechanisms that cause psoriasis, the target cells and antigens that drive pathogenic T cell responses in psoriatic lesions are still unproven and the autoimmune basis of psoriasis still remains hypothetical. However, since the identification of the Th17 cell subset, the IL-23/Th17 immune axis has been considered a key driver of psoriatic inflammation, which has led to the development of biologic agents that target crucial elements of this pathway. Here we present the current understanding of various aspects in psoriasis pathogenesis.