Role of interleukin 1 in atopic dermatitis

Cholesterol Nanofiber Patches with Sustainable Oil Delivery Eliminate Inflammation in Atopic Skin

Atopic skin is dry and itchy and lacks integrity. Impaired skin barrier results from altered lipid composition of the skin. A crucial skin lipid, cholesterol, provides flexibility and homeostasis of the cell membranes' lipid bilayer. Cholesterol-based creams and natural oils, especially blackcurrant seed oil, are beneficial for skin care as they hydrate the skin and improve its integrity. The major atopic symptom, skin dryness, can be overcome by the application of porous patches enhanced with cholesterol and natural oil. The base of the patches is constructed of polyimide (PI) nanofibers with cholesterol coatings and externally added blackcurrant seed oil. The presence of cholesterol in PI mats hinders the passage of oil through the patches to the skin, resulting in sustained and prolonged skin hydration. The theoretical and numerical investigations of oil dynamics in porous mats confirmed the experimental results, showing a prolonged skin hydration effect up to 6 h. Additionally, as demonstrated by in vivo tests on atopic mice, cholesterol patches lower serum immunoglobulin E levels and expression of proinflammatory cytokines in the skin, thereby accelerating skin healing. Our results hold great promise for the long-term application of the patches in atopic dermatitis treatment.

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.

Unraveling Atopic Dermatitis: Insights into Pathophysiology, Therapeutic Advances, and Future Perspectives

Atopic dermatitis (AD) is an inflammatory skin condition that frequently develops before the onset of allergic rhinitis or asthma. More than 10% of children are affected by this serious skin condition, which is painful for the sufferers. Recent research has connected the environment, genetics, the skin barrier, drugs, psychological factors, and the immune system to the onset and severity of AD. The causes and consequences of AD and its cellular and molecular origins are reviewed in this paper. The exploration of interleukins and their influence on the immunological pathway in AD has been facilitated by using relevant biomarkers in clinical trials. This approach enables the identification of novel therapeutic modalities, fostering the potential for targeted translational research within the realm of personalized medicine. This review focuses on AD's pathophysiology and the ever-changing therapeutic landscape. Beyond the plethora of biologic medications in various stages of approval or development, a range of non-biologic targeted therapies, specifically small molecules, have emerged. These include Janus kinase (JAK) inhibitors like Baricitinib, Upadacitinib, and Abrocitinib, thus expanding the spectrum of therapeutic options. This review also addresses the latest clinical efficacy data and elucidates the scientific rationale behind each targeted treatment for atopic dermatitis.

Role of the NLRP1 inflammasome in skin cancer and inflammatory skin diseases

Inflammasomes are cytoplasmic protein complexes that play a crucial role in protecting the host against pathogenic and sterile stressors by initiating inflammation. Upon activation, these complexes directly regulate the proteolytic processing and activation of proinflammatory cytokines interleukin (IL)-1β and IL-18 to induce a potent inflammatory response, and induce a programmed form of cell death called pyroptosis to expose intracellular pathogens to the surveillance of the immune system, thus perpetuating inflammation. There are various types of inflammasome complexes, with the NLRP1 (nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-1) inflammasome being the first one identified and currently recognized as the predominant inflammasome sensor protein in human keratinocytes. Human NLRP1 exhibits a unique domain structure, containing both an N-terminal pyrin (PYD) domain and an effector C-terminal caspase recruitment domain (CARD). It can be activated by diverse stimuli, such as viruses, ultraviolet B radiation and ribotoxic stress responses. Specific mutations in NLRP1 or related genes have been associated with rare monogenic skin disorders, such as multiple self-healing palmoplantar carcinoma; familial keratosis lichenoides chronica; autoinflammation with arthritis and dyskeratosis; and dipeptidyl peptidase 9 deficiency. Recent research breakthroughs have also highlighted the involvement of dysfunctions in the NLRP1 pathway in a handful of seemingly unrelated dermatological conditions. These range from monogenic autoinflammatory diseases to polygenic autoimmune diseases such as vitiligo, psoriasis, atopic dermatitis and skin cancer, including squamous cell carcinoma, melanoma and Kaposi sarcoma. Additionally, emerging evidence implicates NLRP1 in systemic lupus erythematosus, pemphigus vulgaris, Addison disease, Papillon-Lefèvre syndrome and leprosy. The aim of this review is to shed light on the implications of pathological dysregulation of the NLRP1 inflammasome in skin diseases and investigate the potential rationale for targeting this pathway as a future therapeutic approach.

Characterisation of IL-1 family members in Sweet syndrome highlights the overexpression of IL-1β and IL-1R3 as possible therapeutic targets

Sweet syndrome (SS) as a prototypic neutrophilic dermatosis (NDs) shares certain clinical and histologic features with monogenic auto-inflammatory disorders in which interleukin (IL)-1 cytokine family members play an important role. This has led to the proposal that NDs are polygenic auto-inflammatory diseases and has fuelled research to further understand the role of IL-1 family members in the pathogenesis of NDs. The aim of this study was to characterise the expression of the IL-1 family members IL-1β, IL-36γ, IL-33 and IL-1R3 (IL-1RaP) in SS. The expression profile of IL-1β, IL-33, IL-36γ and their common co-receptor IL-1R3 was analysed by immunohistochemistry, in situ hybridisation and double immunofluorescence (IF) in healthy control skin (HC) and lesional skin samples of SS. Marked overexpression of IL-1β in the dermis of SS (p < 0.001), and a non-significant increase in dermal (p = 0.087) and epidermal (p = 0.345) IL-36γ expression compared to HC was observed. Significantly increased IL-1R3 expression within the dermal infiltrate of SS skin samples (p = 0.02) was also observed, whereas no difference in IL-33 expression was found between SS and HC (p = 0.7139). In situ hybridisation revealed a good correlation between gene expression levels and the above protein expression levels. Double IF identifies neutrophils and macrophages as the predominant sources of IL-1β. This study shows that IL-1β produced by macrophages and neutrophils and IL-1R3 are significantly overexpressed in SS, thereby indicating a potential pathogenic role for this cytokine and receptor in SS.

Humulus japonicus ameliorates irritant contact dermatitis by suppressing NF‑κB p65‑dependent inflammatory responses in mice

As a type of contact dermatitis (CD), irritant CD (ICD) is an acute skin inflammation caused by external irritants, such as soap, water and chemicals. Humulus japonicus (HJ) is a herbal medicine widely distributed in Asian countries and has anti-inflammatory, antimicrobial and antioxidant effects. The current study aimed to investigate the anti-dermatitis effect of HJ on ICD and determine the molecular basis of this effect using 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced dermatitis mice models and lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Mice were orally administered HJ and luteolin, the major compound in HJ, and topically administered TPA on the right ear to induce dermatitis. Topical application of TPA induced ear redness, oedema and increased infiltration of neutrophils and macrophages, which ameliorated following HJ and luteolin administration. The gene expression levels of inflammatory cell migrating chemokines, chemokine ligand 3 (CCL3) and chemokine (C-X-C motif) ligand 2 (CXCL2), and pro-inflammatory cytokine, IL-1β, were reduced in the ears of HJ- and luteolin-treated mice. HJ and luteolin also inhibited the gene expression of chemokines, CCL3 and CXCL2, and pro-inflammatory cytokines, IL-1β, IL-6 and TNF-α, in LPS-stimulated RAW264.7 cells. Moreover, HJ and luteolin decreased the expression levels of two key inflammatory enzymes, cyclooxygenase-2 (COX2) and inducible nitric oxide synthase (iNOS), and total and active phosphorylation of NF-κB p65. These results suggest that HJ could have a protective effect against ICD by suppressing inflammatory responses; therefore, HJ is a promising therapeutic strategy for ICD treatment.

Human umbilical cord mesenchymal stem cell treatment alleviates symptoms in an atopic dermatitis-like mouse model

BACKGROUND

Atopic dermatitis (AD) is one of the most common immune and inflammatory skin disorders, leading to insufferable itching and skin abnormalities that seriously affect life quality of patients. There are still huge unmet needs for long-term and effective disease control, despite currently available therapies. Evidenced by some preclinical and clinical studies of AD treatment with stem cells, stem cell treatment could significantly and effectively ameliorate AD symptoms.

OBJECTIVES

To elucidate underlying mechanisms of how stem cells therapy alleviates AD-like symptoms.

METHODS

An AD-like mouse model was constructed and treated with mesenchymal stem cells (MSCs) subcutaneously or subcutaneously combined with intravenously. The differentially expressed genes were sorted out from RNA sequencing results of dorsal skin and blood.

RESULTS

Two injection routes of MSCs could alleviate AD-like symptoms and pathologic changes of the skin and immune organs. RNA sequencing of dorsal skin sections and blood provided gene expression signatures for amelioration of skin defects, inflammatory and immune modulation by MSCs, as well as common AD molecular markers for the skin and blood, which may benefit for clinical diagnosis. IL-1β and its signaling pathway were specifically found to be associated with the development of AD-like dermatitis lesions. MSC treatment effectively inhibited the JAK-STAT pathway and receptors of IL-4, IL-13, IL-17, and IgE.

CONCLUSIONS

MSC therapy could regulate abnormal immune and inflammatory status in AD. Mechanistic exploration will contribute to the development of personalized AD treatment based on MSCs.

The Anti-Atopic Dermatitis Effects of Mentha arvensis Essential Oil Are Involved in the Inhibition of the NLRP3 Inflammasome in DNCB-Challenged Atopic Dermatitis BALB/c Mice

The NLRP3 inflammasome is upregulated by various agents, such as nuclear factor-kappa B (NF-κB), lipopolysaccharide (LPS), and adenosine triphosphate (ATP). The NLRP3 inflammasome facilitations the maturation of interleukin (IL)-1β, a proinflammatory cytokine that is critically involved in the pathogenesis of atopic dermatitis (AD). Although the NLRP3 inflammasome clearly exacerbates AD symptoms such as erythema and pruritus, drugs for AD patients targeting the NLRP3 inflammasome are still lacking. Based on the previous findings that Mentha arvensis essential oil (MAEO) possesses strong anti-inflammatory and anti-AD properties through its inhibition of the ERK/NF-κB signaling pathway, we postulated that MAEO might be capable of modulating the NLRP3 inflammasome in AD. The aim of this research was to investigate whether MAEO affects the inhibition of NLRP3 inflammasome activation in murine bone marrow-derived macrophages (BMDMs) stimulated with LPS + ATP in vitro and in a murine model displaying AD-like symptoms induced by 2,4-dinitrochlorobenzene (DNCB) in vivo. We found that MAEO inhibited the expression of NLRP3 and caspase-1, leading to the suppression of NLRP3 inflammasome activation and IL-1β production in BMDMs stimulated with LPS + ATP. In addition, MAEO exhibited efficacy in ameliorating AD symptoms in a murine model induced by DNCB, as indicated by the reduction in dermatitis score, ear thickness, transepidermal water loss (TEWL), epidermal thickness, and immunoglobulin E (IgE) levels. Furthermore, MAEO attenuated the recruitment of NLRP3-expressing macrophages and NLRP3 inflammasome activation in murine dorsal skin lesions induced by DNCB. Overall, we provide evidence for the anti-AD effects of MAEO via inhibition of NLRP3 inflammasome activation.

Anti-inflammatory effect and metabolic mechanism of BS012, a mixture of Asarum sieboldii, Platycodon grandiflorum, and Cinnamomum cassia extracts, on atopic dermatitis in vivo and in vitro

BACKGROUND

Atopic dermatitis (AD) is a chronic, relapsing skin disease accompanied by itchy and dry skin. AD is caused by complex interactions between innate and adaptive immune response. AD treatment include glucocorticoids and immunosuppressants. However, long-term treatment can have serious side effects. Thus, an effective AD treatment with fewer side effects is required. Natural materials, including herbal medicines, have potential applications.

PURPOSE

This study evaluated the in vivo and in vitro therapeutic effects of BS012, a mixture of Asarum sieboldii, Platycodon grandiflorum, and Cinnamomum cassia extracts, on AD and investigated the underlying metabolic mechanisms.

METHODS

The anti-inflammatory effects of BS012 were assessed using a mouse model of AD induced by 1‑chloro-2,4-dinitrobenzene (DNCB) and in tumor necrosis factor-alpha/interferon-gamma (TNF-α/IFN-γ) stimulated normal human epidermal keratinocytes (NHEKs). In DNCB-induced mice, total dermatitis score, histopathological analysis, and immune cell factors were assessed to evaluate the anti-atopic activity. In TNF-α/IFN-γ-stimulated NHEKs, pro-inflammatory cytokines, chemokines, and related signaling pathways were investigated. Serum and intracellular metabolomics were performed to identify the metabolic mechanism underlying the therapeutic effects of BS012 treatment.

RESULTS

In DNCB-induced mice, BS012 showed potent anti-atopic activity, including reducing AD-like skin lesions and inhibiting the expression of Th2 cytokines and thymic stromal lymphopoietin. In TNF-α/IFN-γ-stimulated keratinocytes, BS012 dose-dependently inhibited the expression of pro-inflammatory cytokines and chemokines by blocking nuclear factor-kappa B and signal transducer and activator of transcription signaling pathways. Serum metabolic profiles of mice revealed significant changes in lipid metabolism related to inflammation in AD. Intracellular metabolome analysis revealed that BS012 treatment affected the metabolism associated with inflammation, skin barrier function, and lipid organization of the stratum corneum.

CONCLUSION

BS012 exerts anti-atopic activity by reducing the Th2-specific inflammatory response and improving skin barrier function in AD in vivo and in vitro. These effects are mainly related to the inhibition of inflammation and recovery of metabolic imbalance in lipid organization. BS012, a novel combination with strong activity in suppressing the Th2-immune response, could be a potential alternative for AD treatment. Furthermore, the metabolic mechanism in vivo and in vitro using a metabolomics approach will provide crucial information for the development of natural products for AD treatment.

The translational revolution in atopic dermatitis: the paradigm shift from pathogenesis to treatment

Atopic dermatitis (AD) is the most common inflammatory skin disease, and it is considered a complex and heterogeneous condition. Different phenotypes of AD, defined according to the patient age at onset, race, and ethnic background; disease duration; and other disease characteristics, have been recently described, underlying the need for a personalized treatment approach. Recent advancements in understanding AD pathogenesis resulted in a real translational revolution and led to the exponential expansion of the therapeutic pipeline. The study of biomarkers in clinical studies of emerging treatments is helping clarify the role of each cytokine and immune pathway in AD and will allow addressing the unique immune fingerprints of each AD subset. Personalized medicine will be the ultimate goal of this targeted translational research. In this review, we discuss the changes in the concepts of both the pathogenesis of and treatment approach to AD, highlight the scientific rationale behind each targeted treatment and report the most recent clinical efficacy data.

Inhibitory Effect of Bisdemethoxycurcumin on DNCB-Induced Atopic Dermatitis in Mice

Atopic dermatitis (AD) is a common chronic inflammatory skin disease. Bisdemethoxycurcumin (BDMC) is an ingredient from the rhizome of the traditional Chinese herbal medicine turmeric. BDMC has been reported to have important pharmacological properties, such as anti-inflammatory, antioxidant, antitumor and antiproliferative activities. However, its effect on atopic dermatitis has not been reported. The purpose of our study was to demonstrate the effectiveness of BDMC on TNF-α/IFNγ-stimulated HaCaT cells and on 2,4-dinitrochlorobenzene (DNCB)-induced AD mice. Our studies showed in vitro that BDMC was able to significantly inhibit the mRNA expression of chemokines and cytokines in TNF-α/IFN-γ-stimulated HaCaT cells and alleviate their inflammatory response. Our studies found in vivo that BDMC was able to significantly improve the symptoms of DNCB-induced AD skin lesions, decrease the number of scratches, ear thickness, and spleen index, improve inflammatory cells and mast cell infiltration and decrease skin thickness. Moreover, it was also able to inhibit the mRNA expression levels of chemokines and inflammatory cytokines and the activation of the MAPK and NF-κB signaling pathways. Thus, the results indicated that BDMC can improve atopic dermatitis in mice and that further clinical studies are warranted on its treatment of AD.

Extract of Wheatgrass and Aronia Mixture Ameliorates Atopic Dermatitis-Related Symptoms by Suppressing Inflammatory Response and Oxidative Stress In Vitro and In Vivo

Atopic dermatitis is regulated by the production of pro-inflammatory cytokines and chemokines via the nuclear factor kappa B or mitogen-activated protein kinase signaling pathways, as well as, the release of oxidative stress-related factors via the NF-E2 p45-related factor 2 signaling pathway. Both wheatgrass (Triticum aestivum L., TA) and aronia (Aronia melanocarpa, AR) are known for their anti-inflammatory and antioxidant properties, however, the anti-inflammatory and antioxidant effects of TA and AR (TAAR) mixture extract have not been elucidated in an atopic dermatitis model. In this study, we assessed the inhibitory effects and underlying molecular mechanism of TAAR extract against lipopolysaccharide-induced inflammation and tumor necrosis factor-α/interferon-γ-induced inflammation and oxidative stress in vitro. We also investigated the alleviating effect of TAAR extract on DNCB-induced atopic dermatitis-like skin lesions in mice in vivo. We found that TAAR extract treatment inhibited inflammatory mediators in both RAW 264.7 cells and HaCaT cells, and increased the expression of oxidative stress defense enzymes in HaCaT cells. Furthermore, treatment of the DNCB-induced mouse model with TAAR extract ameliorated the overall symptoms of atopic dermatitis. Therefore, TAAR extract as a novel natural therapeutic agent may be used for the treatment of atopic dermatitis.

Overcoming drug delivery barriers and challenges in topical therapy of atopic dermatitis: A nanotechnological perspective

Atopic dermatitis (AD) is an inflammatory disorder centered around loss of epidermal barrier function, and T helper 2 (Th2) immune responses. The current understanding of disease heterogeneity and complexity, limits the rational use of existing topical, systemic therapeutic agents, but paves way for development of advanced therapeutic agents. Additionally, advanced nanocarriers that deliver therapeutics to target cells, seem to offer a promising strategy, to overcome intrinsic limitations and challenges of conventional, and traditional drug delivery systems. Ever-evolving understanding of molecular target sites and complex pathophysiology, adverse effects of current therapeutic options, inefficient disease recapitulation by existing animal models are some of the challenges that we face. Also, despite limited success in market translatibility, nanocarriers have demonstrated excellent preclinical results and have been extensively studied for AD. Detailed research on behavior of nanocarriers in different patients and tailored therapy to account for phenotypic variability of the disease are the new research avenues that we look forward to.

Therapeutic potential of targeting IL-1 family cytokines in chronic inflammatory skin diseases

The interleukin-1 (IL-1) family of cytokines is a central regulator of a myriad of immunological responses. It comprises several cytokines, including those belonging to the IL-1, IL-36 and IL-18 subfamilies, as well as IL-33. The IL-1 family primarily plays a role in orchestrating innate immune responses but also in adaptive immunity. Increased interest in the IL-1 family occurred following the discovery that dysregulation of IL-1 signalling underlies the pathogenesis of several monogenic auto-inflammatory diseases, characterized by sterile inflammation involving the skin and other organs. This also provided increased understanding of the role of innate immunity and the IL-1 family in polygenic auto-inflammatory skin conditions, such as neutrophilic dermatoses, as well as in some of the most common chronic inflammatory skin diseases, such as psoriasis or hidradenitis suppurativa. Several therapeutic agents have been developed to inhibit the IL-1 family members and their signalling pathways. These have shown therapeutic efficacy in several chronic inflammatory skin disorders. The aim of this review is to thoroughly describe the consequences of pathological dysregulation of IL-1, IL-33, IL-36, IL-18 pathways in dermatological conditions and to provide a forward-looking update on therapeutic strategies targeting signalling by IL-1 family cytokines.

Cytokines and apoptosis in atopic dermatitis

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease. AD affects 10-20% of children worldwide and persists into adulthood in a minority of cases, affecting approximately 2-3% of the adult population, with an increased prevalence over the past decades in developed countries. Atopy is a genetic tendency to overproduce IgE class antibodies in response to common antigens found in the environment. Concurrence of different atopy such as allergic rhinitis or asthma in children with AD is estimated at 80%. AD is characterized by a vicious cycle of an allergic immune response. The emerging picture of the AD is a complex disorder with barrier dysfunction, immunological, genetic and environmental factors all playing key roles. Patients with severe or persistent disease and their families experience significant impairment in their quality of life, and in addition, AD places a heavy economic burden on society as a whole. Pathogenesis, the role of the epidermal barrier, mechanisms of cells apoptosis, the role of T cells and cytokines in AD are discussed in this article.

Effect of Neferine on DNCB-Induced Atopic Dermatitis in HaCaT Cells and BALB/c Mice

Atopic dermatitis (AD) is a chronic and persistent inflammatory skin disease characterized by eczematous lesions and itching, and it has become a serious health problem. However, the common clinical treatments provide limited relief and are accompanied by adverse effects. Therefore, there is a need to develop novel and effective therapies to treat AD. Neferine is a small molecule compound isolated from the green embryo of the mature seeds of lotus (Nelumbo nucifera). It has a bisbenzylisoquinoline alkaloid structure. Relevant studies have shown that neferine has many pharmacological and biological activities, including anti-inflammatory, anti-thrombotic, and anti-diabetic activities. However, there are very few studies on neferine in the skin, especially the related effects on inflammatory skin diseases. In this study, we proved that it has the potential to be used in the treatment of atopic dermatitis. Through in vitro studies, we found that neferine inhibited the expression of cytokines and chemokines in TNF-α/IFN-γ-stimulated human keratinocyte (HaCaT) cells, and it reduced the phosphorylation of MAPK and the NF-κB signaling pathway. Through in vivo experiments, we used 2,4-dinitrochlorobenzene (DNCB) to induce atopic dermatitis-like skin inflammation in a mouse model. Our results show that neferine significantly decreased the skin barrier damage, scratching responses, and epidermal hyperplasia induced by DNCB. It significantly decreased transepidermal water loss (TEWL), erythema, blood flow, and ear thickness and increased surface skin hydration. Moreover, it also inhibited the expression of cytokines and the activation of signaling pathways. These results indicate that neferine has good potential as an alternative medicine for the treatment of atopic dermatitis or other skin-related inflammatory diseases.

Inflammasome Activation in Pollution-Induced Skin Conditions

SUMMARY

Exposure to air pollutants has been now associated with detrimental effects on a variety of organs, including the heart, lungs, GI tract, and brain. However, recently it has become clear that pollutant exposure can also promote the development/exacerbation of a variety of skin conditions, including premature aging, psoriasis, acne, and atopic dermatitis. Although the molecular mechanisms by which pollutant exposure results in these cutaneous pathological manifestations, it has been noticed that an inflammatory status is a common denominator of all those skin conditions. For this reason, recently, the activation of a cytosolic multiprotein complex involved in inflammatory responses (the inflammasome) that could promote the maturation of proinflammatory cytokines interleukin-1β and interleukin-18 has been hypothesized to play a key role in pollution-induced skin damage. In this review, we summarize and propose the cutaneous inflammasome as a novel target of pollutant exposure and the eventual usage of inflammasome inhibitor as new technologies to counteract pollution-induced skin damage. Possibly, the ability to inhibit the inflammasome activation could prevent cutaneous inflammaging and ameliorate the health and appearance of the skin.

Ruxolitinib Cream Has Dual Efficacy on Pruritus and Inflammation in Experimental Dermatitis

The goal of this study was to elucidate the anti-pruritic and anti-inflammatory efficacy of ruxolitinib cream in experimentally-induced dermatitis. Atopic dermatitis (AD), the most common chronic relapsing inflammatory skin disease, significantly impairs patients' quality of life, with pruritus being a common complaint. The sensation of itch results from the interplay between epidermal barrier dysfunction, upregulated immune signaling and the activation of the central nervous system. The Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway plays a central role in pro-inflammatory cytokine signaling in AD. Ruxolitinib cream is a potent and selective JAK1/2 inhibitor currently undergoing clinical evaluation in adults with mild-to-moderate AD (NCT03745638, NCT03920852 and NCT03745651). The efficacy of ruxolitinib cream was tested in murine models of acute and chronic dermatitis and was also characterized in an ex vivo human skin dermatitis model. Ruxolitinib cream was highly effective at ameliorating disease symptoms in multiple murine dermatitis models through downregulation of T helper (Th)2-driven inflammation, resulting in reduced skin thickening and decreased itch. Pathway analysis of mouse ear tissue and human skin explants underscored the role for ruxolitinib in ameliorating inflammation and reducing itch via modulation of the JAK-STAT pathway. Together, the data offer a strong rationale for the use of ruxolitinib cream as a potent therapeutic agent for the clinical management of atopic dermatitis.

Efficacy of biologics in atopic dermatitis

Introduction: Atopic dermatitis (AD) is a heterogeneous disease. Recent advancements in understanding AD pathogenesis resulted in the exponential expansion of its therapeutic pipeline, particularly following the success and FDA-approval of dupilumab. Different phenotypes of AD by age and ethnicity have also recently been described and clinical studies of emerging treatments will further clarify the role of each cytokine pathway in AD.Areas covered: We review the impressive repertoire of biologics for treatment of moderate-to-severe AD, including those targeting Th2, Th22, Th17/IL-23 and IgE. We highlight the scientific rationale behind each approach and provide a discussion of the most recent clinical efficacy and safety data.Expert opinion: AD is a complex disease and recent research has identified numerous endotypes, reinforcing the rationale for developing targeted therapeutics to antagonize these factors. Dupilumab has revolutionized AD treatment and its mechanistic studies also offer crucial insight into AD pathogenesis. Nevertheless, this biologic does not work for everyone, highlighting the need for a more precise approach to address the unique immune fingerprints of each AD subset. Ultimately targeted therapeutics will complement our understanding of the AD molecular map and help push AD management into an era of personalized medicine.

Claudin-1 decrease impacts epidermal barrier function in atopic dermatitis lesions dose-dependently

The transmembrane protein claudin-1 is a major component of epidermal tight junctions (TJs), which create a dynamic paracellular barrier in the epidermis. Claudin-1 downregulation has been linked to atopic dermatitis (AD) pathogenesis but variable levels of claudin-1 have also been observed in healthy skin. To elucidate the impact of different levels of claudin-1 in healthy and diseased skin we determined claudin-1 levels in AD patients and controls and correlated them to TJ and skin barrier function. We observed a strikingly broad range of claudin-1 levels with stable TJ and overall skin barrier function in healthy and non-lesional skin. However, a significant decrease in TJ barrier function was detected in lesional AD skin where claudin-1 levels were further reduced. Investigations on reconstructed human epidermis expressing different levels of claudin-1 revealed that claudin-1 levels correlated with inside-out and outside-in barrier function, with a higher coherence for smaller molecular tracers. Claudin-1 decrease induced keratinocyte-autonomous IL-1β expression and fostered inflammatory epidermal responses to non-pathogenic Staphylococci. In conclusion, claudin-1 decrease beyond a threshold level results in TJ and epidermal barrier function impairment and induces inflammation in human epidermis. Increasing claudin-1 levels might improve barrier function and decrease inflammation and therefore be a target for AD treatment.

Subcutaneous injection of recombinant heat shock protein 70 ameliorates atopic dermatitis skin lesions in a mouse model

Atopic dermatitis (AD) is a chronic inflammatory skin disease and sometimes is a tough challenge for physicians. We previously reported that in Th2 environment, the production and secretion of thymic stromal lymphopoietin (TSLP) from human keratinocytes was inhibited by recombinant heat shock protein 70 (rHSP70). The present study assessed the therapeutic effectiveness of rHSP70 in a mouse model of AD. An experimental model of AD was reproduced by systemic sensitization and local epicutaneous challenge with ovalbumin (OVA). Treatment of rHSP70 was performed by subcutaneous administration. The levels of OVA-specific IgE, as well as cytokines, were detected by ELISA. Skin samples from patch areas were also taken for histologic examination. Injection of rHSP70 improved the histologic picture by reducing the thickness of epidermis and allergic inflammation. Skin sonography revealed rHSP70 ameliorated skin remodeling. rHSP70 also significantly decreased the protein expression of TSLP of skin from patch areas. Furthermore, in ex vivo studies also showed group of rHSP70 treatment decreased IL-13, RANTES, MIP-1β and increased IFN-γ secreted from splenocytes stimulated with OVA. The rHSP70 intervention in the mouse model of AD reduced the skin expression of TSLP and attenuated the clinical appearance of OVA-induced AD mice. The effect was achieved by suppressed Th2 immune response in injected skin tissue and enhanced systemic Th1 immune response. These results suggest that rHSP70 have potential as a promising protein for the treatment of AD.

Application of an agr-Specific Antivirulence Compound as Therapy for Staphylococcus aureus-Induced Inflammatory Skin Disease

Atopic dermatitis (AD) is a chronic inflammatory skin disease where more than 90% of patients affected are colonized with Staphylococcus aureus. In AD, S. aureus δ-toxin is a major virulence factor causing cutaneous inflammation via mast cell degranulation. δ-toxin is controlled by the S. aureus agr quorum sensing system, and thus we addressed whether interference with agr signaling would limit skin inflammation. Indeed, treatment of S. aureus with the agr-inhibitor solonamide B (SolB) abolished δ-toxin production and reduced skin inflammation in a mouse model of inflammatory skin disease, demonstrating the potential of antivirulence therapy in treating S. aureus-induced skin disorders.

Effects and mechanism of action of Huang-Lian-Jie-Du-Tang in atopic dermatitis-like skin dysfunction in vivo and in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Atopic dermatitis (AD), a disorder prevalent during childhood and adulthood, seriously affects the patient's quality of life. Although Huang-Lian-Jie-Du-Tang (HLJDT) has shown anti-inflammatory effects in previous studies, its effects and mechanism of action underlying AD disorder are still largely unknown.

OBJECTIVE

This study explored the anti-inflammatory and immunomodulatory effects of HLJDT on the AD-like dermal disorder, induced in vitro by lipopolysaccharide (LPS)-triggered inflammation, and in vivo by 2,4-dinitrochlorobenzene (DNCB).

MATERIALS AND METHODS

In vivo HLJDT effects were investigated by determining the severity of dermatitis, which consisted of observing signs of skin lesions, visually and through haematoxylin and eosin (HE) staining, in mouse ears and dorsal skin, measuring serum levels of interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-5, IL-6, interferon (IFN)-γ, the tumour necrosis factor (TNF)-α, and determining the splenic index, number of splenic CD4⁺/CD8⁺ T-lymphocytes, as well as the phosphorylation levels of mitogen-activated protein kinases (including MAPKs-p38, ERK, and JNK), IκB-α, and nuclear factor kappa B (NF-κB) (p65) within dermal lesions. Morphological changes in LPS-induced inflammation were observed under a microscope, and ELISA and qPCR assays were used to measure IL-1α, IL-1β, IL-6, and TNF-α expression levels. The protein expression levels of P-ERK/ERK, P-p38/p38, P-JNK/JNK, P-IKβ-α, and P-p65 were measured through western blotting. Additionally, p65 expression was assessed by immunofluorescence, and LPS binding to RAW264.7 cell membrane was studied with laser confocal microscopy.

RESULTS

HLJDT could remarkably mitigate DNCB-induced AD-like lesion symptoms, alleviating inflammatory mediator infiltration in mouse ears and dorsal skin tissue, down-regulating serum expression levels of IL-1α, IL-1β, IL-2, IL-4, IL-5, IL-6, IFN-γ, and TNF-α, normalising the splenic CD4⁺/CD8⁺ T-lymphocyte ratio, and inactivating MAPKs (including p38, ERK, and JNK), IκB-α, and NF-κB (p65) in dorsal skin. Furthermore, HLJDT inhibited LPS-induced differentiation of RAW264.7 cells, as evidenced by the decreased protein and mRNA expression of IL-1α, IL-1β, IL-6, and TNF-α. Additionally, it decreased ERK, p38, JNK, IKβ-α, and p65 phosphorylation levels in the MAPKs/NF-κB pathway, inhibited p65 nuclear translocation, and reduced LPS binding to the RAW264.7 cell membrane.

CONCLUSIONS

HLJDT significantly improved AD-like symptoms via inhibition of the MAPKs/NF-κB pathway. Therefore, administration of HLJDT might be a potential treatment for AD in the clinical setting.

Interleukin 1-β, interleukin-1 receptor antagonist and vitamin D levels in children with atopic dermatitis

Introduction

Among the broad spectrum of cytokines, interleukin 1-β (IL-1β) has been implicated in induction and subsequent aggravation of skin lesions in atopic dermatitis (AD). A considerable body of evidence suggests that vitamin D status also influences the risk and/or severity of AD.

Material and methods

Fifty-seven children suffering from mild to severe AD were enrolled in the study. The control group consisted of 33 matched healthy children. In all the children serum concentrations of IL-1β/IL-1F2 and the interleukin-1 receptor antagonist IL-Ra/1F3 were measured. Serum 25(OH)D concentration was obtained for 49 patients with AD and all healthy children.

Results

In children with AD 59.2% of children had insufficiency, 24.5% had deficiency and 16.3% had a sufficient serum 25(OH)D level. In the control group 26.5%, 52.9% and 20% of participants had insufficiency/deficiency/sufficiency of 25(OH)D, respectively. The severity of AD was positively correlated with total IgE level, percentage and absolute count of eosinophils and IL-1Ra. IL-1β correlated with IL-1Ra.

Conclusions

In children with AD the serum vitamin D level was lower than in healthy children. The correlation between severity of AD and IL-1Ra may prove that inflammasome-dependent IL-1β is involved in immunopathogenesis of the disease. Further studies are needed on a larger population of children to confirm the role of this cytokine in development of AD.

Chitosan-based nanoformulated (-)-epigallocatechin-3-gallate (EGCG) modulates human keratinocyte-induced responses and alleviates imiquimod-induced murine psoriasiform dermatitis

Background

Psoriasis is a chronic and currently incurable inflammatory skin disease characterized by hyperproliferation, aberrant differentiation, and inflammation, leading to disrupted skin barrier function. The use of natural agents that can abrogate these effects could be useful for the treatment of psoriasis. Earlier studies have shown that treatment of keratinocytes and mouse skin with the green tea polyphenol (−)-epigallocatechin-3-gallate (EGCG) mitigated inflammation and increased the expression of caspase-14 while promoting epidermal differentiation and cornification. However, bioavailability issues have restricted the development of EGCG for the treatment of psoriasis.

Materials and methods

To overcome these limitations, we employed a chitosan-based polymeric nanoparticle formulation of EGCG (CHI-EGCG-NPs, hereafter termed nanoEGCG) suitable for topical delivery for treating psoriasis. We investigated and compared the efficacy of nanoEGCG versus native or free EGCG in vitro and in an in vivo imiquimod (IMQ)-induced murine psoriasis-like dermatitis model. The in vivo relevance and efficacy of nanoEGCG formulation (48 µg/mouse) were assessed in an IMQ-induced mouse psoriasis-like skin lesion model compared to free EGCG (1 mg/mouse).

Results

Like free EGCG, nanoEGCG treatment induced differentiation, and decreased proliferation and inflammatory responses in cultured keratinocytes, but with a 4-fold dose advantage. Topically applied nanoEGCG elicited a significant (p<0.01) amelioration of psoriasiform pathological markers in IMQ-induced mouse skin lesions, including reductions in ear and skin thickness, erythema and scales, proliferation (Ki-67), infiltratory immune cells (mast cells, neutrophils, macrophages, and CD4⁺ T cells), and angiogenesis (CD31). We also observed increases in the protein expression of caspase-14, early (keratin-10) and late (filaggrin and loricrin) markers of differentiation, and the activator protein-1 factor (JunB). Importantly, a significant modulation of several psoriasis-related inflammatory cytokines and chemokines was observed compared to the high dose of free EGCG (p<0.05). Taken together, topically applied nanoEGCG displayed a >20-fold dose advantage over free EGCG.

Conclusion

Based on these observations, our nanoEGCG formulation represents a promising drug-delivery strategy for treating psoriasis and possibly other inflammatory skin diseases.

Inflammatory cytokines and biofilm production sustain Staphylococcus aureus outgrowth and persistence: a pivotal interplay in the pathogenesis of Atopic Dermatitis

Individuals with Atopic dermatitis (AD) are highly susceptible to Staphylococcus aureus colonization. However, the mechanisms driving this process as well as the impact of S. aureus in AD pathogenesis are still incompletely understood. In this study, we analysed the role of biofilm in sustaining S. aureus chronic persistence and its impact on AD severity. Further we explored whether key inflammatory cytokines overexpressed in AD might provide a selective advantage to S. aureus. Results show that the strength of biofilm production by S. aureus correlated with the severity of the skin lesion, being significantly higher (P < 0.01) in patients with a more severe form of the disease as compared to those individuals with mild AD. Additionally, interleukin (IL)-β and interferon γ (IFN-γ), but not interleukin (IL)-6, induced a concentration-dependent increase of S. aureus growth. This effect was not observed with coagulase-negative staphylococci isolated from the skin of AD patients. These findings indicate that inflammatory cytokines such as IL1-β and IFN-γ, can selectively promote S. aureus outgrowth, thus subverting the composition of the healthy skin microbiome. Moreover, biofilm production by S. aureus plays a relevant role in further supporting chronic colonization and disease severity, while providing an increased tolerance to antimicrobials.

Inflammasomes and dermatology

Inflammasomes are intracellular multiprotein complexes that comprise part of the innate immune response. Since their definition, inflammasome disorders have been linked to an increasing number of diseases. Autoinflammatory diseases refer to disorders in which local factors lead to the activation of innate immune cells, causing tissue damage when in the absence of autoantigens and autoantibodies. Skin symptoms include the main features of monogenic inflammasomopathies, such as Cryopyrin-Associated Periodic Syndromes (CAPS), Familial Mediterranean Fever (FMF), Schnitzler Syndrome, Hyper-IgD Syndrome (HIDS), PAPA Syndrome, and Deficiency of IL-1 Receptor Antagonist (DIRA). Concepts from other pathologies have also been reviewed in recent years, such as psoriasis, after the recognition of a combined contribution of innate and adaptive immunity in its pathogenesis. Inflammasomes are also involved in the response to various infections, malignancies, such as melanoma, autoimmune diseases, including vitiligo and lupus erythematosus, atopic and contact dermatitis, acne, hidradenitis suppurativa, among others. Inhibition of the inflammasome pathway may be a target for future therapies, as already occurs in the handling of CAPS, through the introduction of IL-1 inhibitors. This study presents a literature review focusing on the participation of inflammasomes in skin diseases.

Lithospermum erythrorhizon extract inhibits Der p2-induced inflammatory response through alleviation of thymic stromal lymphopoietin, nuclear factor Kappa B, and inflammasome expression in human bronchial epithelial cells

ETHNOPHARMACOLOGICAL RELEVANCE

Lithospermum erythrorhizon (LE) and Angelica sinensis (AS), widely used in several folk medicine for wound, pus discharge and dermatitis for the history of several hundred years in Asian countries.

AIM OF STUDY

To investigate the therapeutic effect of LE and AS on Der p2-induced inflammatory response in human bronchial epithelial (BEAS-2B) cells.

METHODS

The effects of Der p2 stimulation on thymic stromal lymphopoietin (TSLP), the nuclear factor kappa B (NF-κB) pathway, the inflammasome (specifically, the apoptosis speck-like protein [ASC] and nod-like receptor 3 [NLRP3]), Caspase-1 and the signal transducer and activator of transcription (STAT) 3 pathway were evaluated in the human bronchial epithelial (BEAS-2B) cells.

RESULTS

The results indicated that LE, AS, and LE+AS reduced TSLP, I kappa B kinase-α, and NLRP3 levels; LE and AS reduced Caspase-1; LE and LE+AS also reduced NF-κB p50, NF-κB p65, ASC, and STAT3 levels.

CONCLUSION

Both LE and AS aqueous extracts exert anti-inflammatory effects in Der p2-stimulated BEAS-2B cells. These effects may involve multiple mechanisms, including the inhibition of TSLP production as well as the suppression of IKKα, Caspase-1 and NLRP3; however, additional studies are warranted to elucidate the underlying mechanisms.

Guanine nucleotide exchange factor RABGEF1 regulates keratinocyte-intrinsic signaling to maintain skin homeostasis

Epidermal keratinocytes form a structural and immune barrier that is essential for skin homeostasis. However, the mechanisms that regulate epidermal barrier function are incompletely understood. Here we have found that keratinocyte-specific deletion of the gene encoding RAB guanine nucleotide exchange factor 1 (RABGEF1, also known as RABEX-5) severely impairs epidermal barrier function in mice and induces an allergic cutaneous and systemic phenotype. RABGEF1-deficient keratinocytes exhibited aberrant activation of the intrinsic IL-1R/MYD88/NF-κB signaling pathway and MYD88-dependent abnormalities in expression of structural proteins that contribute to skin barrier function. Moreover, ablation of MYD88 signaling in RABGEF1-deficient keratinocytes or deletion of Il1r1 restored skin homeostasis and prevented development of skin inflammation. We further demonstrated that epidermal RABGEF1 expression is reduced in skin lesions of humans diagnosed with either atopic dermatitis or allergic contact dermatitis as well as in an inducible mouse model of allergic dermatitis. Our findings reveal a key role for RABGEF1 in dampening keratinocyte-intrinsic MYD88 signaling and sustaining epidermal barrier function in mice, and suggest that dysregulation of RABGEF1 expression may contribute to epidermal barrier dysfunction in allergic skin disorders in mice and humans. Thus, RABGEF1-mediated regulation of IL-1R/MYD88 signaling might represent a potential therapeutic target.

The Role of Interleukin-1 in Inflammatory and Malignant Human Skin Diseases and the Rationale for Targeting Interleukin-1 Alpha

Inflammation plays a major role in the induction and progression of several skin diseases. Overexpression of the major epidermal proinflammatory cytokines interleukin (IL) 1 alpha (IL-1α) and 1 beta (IL-1β) is positively correlated with symptom exacerbation and disease progression in psoriasis, atopic dermatitis, neutrophilic dermatoses, skin phototoxicity, and skin cancer. IL-1β and the interleukin-1 receptor I (IL-1RI) have been used as a therapeutic target for some autoinflammatory skin diseases; yet, their system-wide effects limit their clinical usage. Based on the local effects of extracellular IL-1α and its precursor, pro-IL-1α, we hypothesize that this isoform is a promising drug target for the treatment and prevention of many skin diseases. This review provides an overview on IL-1α and IL-β functions, and their contribution to inflammatory and malignant skin diseases. We also discuss the current treatment regimens, and ongoing clinical trials, demonstrating the potential of targeting IL-1α, and not IL-1β, as a more effective strategy to prevent or treat the onset and progression of various skin diseases.

Expression density of receptors to IL-1β in atopic dermatitis

Interleukin 1 (IL-1 β) and the system for regulation of its biological effects play an important role in the development and behavior of inflammatory processes in atopic dermatitis. Notably, cells that are actively involved in the pathological process have altered expression of cytokine receptors. However, standard evaluation of cells by flow cytometry measures only the percentage of cells expressing the appropriate marker, which is not enough for a full assessment of these changes. The aim of this study was to investigate changes in the expression of IL-1β cytokine receptors in patients with atopic dermatitis by both percentage of cells with receptors in various subsets and the absolute number of membrane-bound receptors themselves. It was found that an increase or decrease in the percentage of cells expressing the receptors in subsets of immune cells in patients with atopic dermatitis was not associated with a change in the number of receptors on the cell surface. Moreover, the changes in the percentage of cells and the number of receptors may occur in different directions, as shown for IL-1R2 expression on B cells and IL-1R1 expression for monocytes. Changes in the parameters of IL-1β receptor expressions are associated with disease severity index SCORAD in atopic dermatitis. These findings underline the importance of studying the density of cytokine receptor expression in the pathology.

Biological Treatments in Atopic Dermatitis

Atopic dermatitis (AD) is one of the most common chronic inflammatory skin diseases that affect both children and adults with a prevalence of 30% and 10%, respectively. Even though most of patients respond satisfactory to topical anti-inflammatory drugs, about 10% require one or more systemic treatments to achieve good control of their illness. The progressive and increasingly detailed knowledge in the immunopathogenesis of AD has allowed research on new therapeutic targets with very promising results in the field of biological therapy. In this article, we will review the different biological treatments with a focus on novel drugs. Their mechanism of action, current status and results from clinical trials and observational studies will be specified.