Keratinocytes in atopic dermatitis express abundant ΔNp73 regulating thymic stromal lymphopoietin production via NF-κB

High mobility group box 1 cytokine targeted topical delivery of resveratrol embedded nanoemulgel for the management of atopic dermatitis

Resveratrol is a polyphenolic compound showing anti-inflammatory activity by inhibition of high mobility group box 1 cytokine responsible for the activation of nuclear factor-κB pathway in atopic dermatitis. To evaluate the efficacy of resveratrol through topical route we have developed resveratrol-loaded nanoemulgel for the effective management of atopic dermatitis in mice model. The resveratrol-loaded nanoemulsion (0.5%, 0.75% and 1% w/w) was optimized by spontaneous nano-emulsification. The optimized resveratrol-loaded nanoemulsions showed average globule size in the 180-230 nm range and found to be monodispersed. The resveratrol nanoemulgel was prepared with a SEPINEO™ P 600 gel base and propylene glycol. Ex vivo permeation and retention study resulted in significantly higher skin retention of resveratrol from resveratrol-loaded nanoemulgel than free resveratrol-loaded gel. Preclinical efficacy of resveratrol nanoemulgel displayed promising therapeutic outcomes where, western blotting of skin tissues disclosed a significant reduction in the relative expression of high mobility group box 1, the receptor for advanced glycation end products, toll-like receptor-4 and phosphorylated nuclear factor-κB. Further, real-time polymerase chain reaction also disclosed a significant reduction in pro-inflammatory cytokines such as thymic stromal lymphopoietin, interleukin-4, interleukin-13, interleukin-31, tumor necrosis factor-α and interleukin-6. The histopathological examination of skin sections showed improvement in the skin condition. Collectively, the findings from our study showcased the significant improvement in the atopic dermatitis skin condition in mice model after topical application of resveratrol loaded nanoemulgel.

The beneficial effects of ethanolic extract of Sargassum serratifolium in DNCB-induced mouse model of atopic dermatitis

Atopic dermatitis is a chronic complex inflammatory skin disorder that requires sustainable treatment methods due to the limited efficacy of conventional therapies. Sargassum serratifolium, an algal species with diverse bioactive substances, is investigated in this study for its potential benefits as a therapeutic agent for atopic dermatitis. RNA sequencing of LPS-stimulated macrophages treated with ethanolic extract of Sargassum serratifolium (ESS) revealed its ability to inhibit a broad range of inflammation-related signaling, which was proven in RAW 264.7 and HaCaT cells. In DNCB-induced BALB/c or HR-1 mice, ESS treatment improved symptoms of atopic dermatitis within the skin, along with histological improvements such as reduced epidermal thickness and infiltration of mast cells. ESS showed a tendency to improve serum IgE levels and inflammation-related cytokine changes, while also improving the mRNA expression levels of Chi3l3, Ccr1, and Fcεr1a genes in the skin. Additionally, ESS compounds (sargachromanol (SCM), sargaquinoic acid (SQA), and sargahydroquinoic acid (SHQA)) mitigated inflammatory responses in LPS-treated RAW264.7 macrophages. In summary, ESS has an anti-inflammatory effect and improves atopic dermatitis, ESS may be applied as a therapeutics for atopic dermatitis.

p73 isoforms meet evolution of metastasis

Cancer largely adheres to Darwinian selection. Evolutionary forces are prominent during metastasis, the final and incurable disease stage, where cells acquire combinations of advantageous phenotypic features and interact with a dynamically changing microenvironment, in order to overcome the metastatic bottlenecks, while therapy exerts additional selective pressures. As a strategy to increase their fitness, tumors often co-opt developmental and tissue-homeostasis programs. Herein, 25 years after its discovery, we review TP73, a sibling of the cardinal tumor-suppressor TP53, through the lens of cancer evolution. The TP73 gene regulates a wide range of processes in embryonic development, tissue homeostasis and cancer via an overwhelming number of functionally divergent isoforms. We suggest that TP73 neither merely mimics TP53 via its p53-like tumor-suppressive functions, nor has black-or-white-type effects, as inferred by the antagonism between several of its isoforms in processes like apoptosis and DNA damage response. Rather, under dynamic conditions of selective pressure, the various p73 isoforms which are often co-expressed within the same cancer cells may work towards a common goal by simultaneously activating isoform-specific transcriptional and non-transcriptional programs. Combinatorial co-option of these programs offers selective advantages that overall increase the likelihood for successfully surpassing the barriers of the metastatic cascade. The p73 functional pleiotropy-based capabilities might be present in subclonal populations and expressed dynamically under changing microenvironmental conditions, thereby supporting clonal expansion and propelling evolution of metastasis. Deciphering the critical p73 isoform patterns along the spatiotemporal axes of tumor evolution could identify strategies to target TP73 for prevention and therapy of cancer metastasis.

Dual Role of p73 in Cancer Microenvironment and DNA Damage Response

Understanding the mechanisms that regulate cancer progression is pivotal for the development of new therapies. Although p53 is mutated in half of human cancers, its family member p73 is not. At the same time, isoforms of p73 are often overexpressed in cancers and p73 can overtake many p53 functions to kill abnormal cells. According to the latest studies, while p73 represses epithelial–mesenchymal transition and metastasis, it can also promote tumour growth by modulating crosstalk between cancer and immune cells in the tumor microenvironment, M2 macrophage polarisation, Th2 T-cell differentiation, and angiogenesis. Thus, p73 likely plays a dual role as a tumor suppressor by regulating apoptosis in response to genotoxic stress or as an oncoprotein by promoting the immunosuppressive environment and immune cell differentiation.

Role of Epithelium-Derived Cytokines in Atopic Dermatitis and Psoriasis: Evidence and Therapeutic Perspectives

Atopic dermatitis and psoriasis are two of the most common chronic skin conditions. Current target therapies represent viable and safe solutions for the most severe cases of these two dermatoses but, presently, several limitations exist in terms of efficacy and side effects. A new class of products, epithelium-derived cytokines (TSLP, IL-25, IL-33), show an increasing potential for use in target therapy for these patients, and demonstrate a direct link between a generalized inflammatory and oxidative stress status and the human skin. A review was conducted to better understand their role in the aforementioned conditions. Of these three molecules, TSLP led has been most often considered in studies regarding target therapies, and most of the results in the literature are related to this cytokine. These three cytokines share common stimuli and are linked to each other in both acute and chronic phases of these diseases, and have been challenged as target therapies or biomarkers of disease activity. The results lead to the conclusion that epithelium-derived cytokines could represent a therapeutic opportunity for these patients, especially in itch control. Furthermore, they might work better when paired together with currently available therapies or in combination with in-development treatments. Further studies are needed in order to verify the efficacy and safety of the biologic treatments currently under development.

The Keratinocyte as a Crucial Cell in the Predisposition, Onset, Progression, Therapy and Study of the Atopic Dermatitis

The keratinocyte (KC) is the main functional and structural component of the epidermis, the most external layer of the skin that is highly specialized in defense against external agents, prevention of leakage of body fluids and retention of internal water within the cells. Altered epidermal barrier and aberrant KC differentiation are involved in the pathophysiology of several skin diseases, such as atopic dermatitis (AD). AD is a chronic inflammatory disease characterized by cutaneous and systemic immune dysregulation and skin microbiota dysbiosis. Nevertheless, the pathological mechanisms of this complex disease remain largely unknown. In this review, we summarize current knowledge about the participation of the KC in different aspects of the AD. We provide an overview of the genetic predisposing and environmental factors, inflammatory molecules and signaling pathways of the KC that participate in the physiopathology of the AD. We also analyze the link among the KC, the microbiota and the inflammatory response underlying acute and chronic skin AD lesions.

IL-13 modulates ∆Np63 levels causing altered expression of barrier- and inflammation-related molecules in human keratinocytes: A possible explanation for chronicity of atopic dermatitis

BACKGROUND

Barrier disruption and an excessive immune response in keratinocytes are now considered to have important roles in the pathophysiology of atopic dermatitis (AD). Furthermore, disturbed keratinocyte differentiation is considered to underlie AD. ΔNp63, a p53-like transcription factor, is a major regulator of keratinocyte differentiation. However, the functional significance of ΔNp63 in AD has not been clarified.

OBJECTIVE

In this study, we aimed to investigate the influence of the type 2 inflammatory environment on ΔNp63 expression and AD-associated molecules regulated by ΔNp63 in keratinocytes.

METHODS

The immunohistochemical expression profiles of ΔNp63 and AD-related molecules were evaluated in human skin tissue. The function of ΔNp63 in the regulation of AD-related molecules and the influence of the type 2 inflammatory environment on ΔNp63 expression were investigated using human primary keratinocytes. Expression of ΔNp63 was manipulated using the RNA interfering method.

RESULTS

In healthy skin tissue, we observed an inverse expression pattern between ∆Np63 and some barrier-related proteins including filaggrin, caspase-14, claudin-1, and claudin-4. ΔNp63 regulated expression of these genes and proteins. In addition, production of IL-1β and IL-33, pro-inflammatory cytokines, was modulated by ΔNp63. Furthermore, prolonged IL-13 exposure increased the thickness of the three-dimensional culture of keratinocytes. IL-13 interfered with ΔNp63 downregulation during calcium-induced keratinocyte differentiation. IL-13 modulated some barrier-related and inflammation-related molecules, which were regulated by ΔNp63.

CONCLUSIONS

We have shown that ΔNp63 modulated AD-related barrier and inflammatory molecules. In addition, ΔNp63 expression was affected by IL-4/IL-13. IL-13-ΔNp63 axis would integrate two major factors of AD pathogenesis: dysregulated barrier and inflammation.

EAACI Biologicals Guidelines-dupilumab for children and adults with moderate-to-severe atopic dermatitis

Atopic dermatitis imposes a significant burden on patients, families and healthcare systems. Management is difficult, due to disease heterogeneity, co-morbidities, complexity in care pathways and differences between national or regional healthcare systems. Better understanding of the mechanisms has enabled a stratified approach to the management of atopic dermatitis, supporting the use of targeted treatments with biologicals. However, there are still many issues that require further clarification. These include the definition of response, strategies to enhance the responder rate, the duration of treatment and its regimen (in the clinic or home-based), its cost-effectiveness and long-term safety. The EAACI Guidelines on the use of dupilumab in atopic dermatitis follow the GRADE approach in formulating recommendations for each outcome and age group. In addition, future approaches and research priorities are discussed.

Advances in Understanding the Initial Steps of Pruritoceptive Itch: How the Itch Hits the Switch

Pruritoceptive (dermal) itch was long considered an accompanying symptom of diseases, a side effect of drug applications, or a temporary sensation induced by invading pruritogens, as produced by the stinging nettle. Due to extensive research in recent years, it was possible to provide detailed insights into the mechanism of itch mediation and modulation. Hence, it became apparent that pruritus is a complex symptom or disease in itself, which requires particular attention to improve patients’ health. Here, we summarize recent findings in pruritoceptive itch, including how this sensation is triggered and modulated by diverse endogenous and exogenous pruritogens and their receptors. A differentiation between mediating pruritogen and modulating pruritogen seems to be of great advantage to understand and decipher the molecular mechanism of itch perception. Only a comprehensive view on itch sensation will provide a solid basis for targeting this long-neglected adverse sensation accompanying numerous diseases and many drug side effects. Finally, we identify critical aspects of itch perception that require future investigation.

Inhibition of the Warm Temperature-Activated Ca2+-Permeable Transient Receptor Potential Vanilloid TRPV3 Channel Attenuates Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by cutaneous lesions and intense pruritus. The warm temperature-activated Ca2+-permeable transient receptor potential vanilloid (TRPV)3 channel is abundantly expressed in keratinocytes, and gain-of-function mutations of TRPV3 cause skin lesions and pruritus in rodents and humans, suggesting an involvement of TRPV3 in the pathogenesis of AD. Here we report that pharmacological and genetic inhibition of TRPV3 attenuates skin lesions and dermatitis in mice. We found that TRPV3 proteins, together with inflammatory factors tumor necrosis factor (TNF)-α and interleukin (IL)-6, were upregulated in the skin of mice in a AD-like model induced by topical application of chemical 2,4-dinitrofluorobenzene, as detected by Western blot analysis and immunostaining assays. Pharmacological activation of TRPV3 by channel agonist and skin sensitizer carvacrol resulted in the development of AD in wild-type mice but not in TRPV3 knockout mice. Furthermore, inhibition of TRPV3 by natural osthole reversed the severity of inflammatory dorsal skin and ear edema in a dose-dependent manner and also decreased expression of inflammatory factors TNF-α and IL-6. Taken together, our findings demonstrate the involvement of overactive TRPV3 in the progressive pathology of AD in mice, and topical inhibition of TRPV3 channel function may represent an effective option for preventing and treating AD or inflammatory skin diseases. SIGNIFICANCE STATEMENT: The overactive transient receptor potential vanilloid TRPV3 channel is critically involved in the pathogenesis of atopic dermatitis. Inhibition of TRPV3 channel function by topical natural osthole may represent an effective therapy for management of atopic dermatitis aimed at preventing or alleviating skin lesions and severe itching.

Differential bronchial epithelial response regulated by ΔNp63: a functional understanding of the epithelial shedding found in asthma

Bronchial epithelial cells serve as a physical barrier at the forefront of the immune system. Barrier disruption and an excessive immune response of the bronchial epithelium contribute to the pathophysiology of asthma, a chronic bronchial inflammatory disease. The purpose of this study was to investigate the functional significance of ΔNp63, a p53-like transcription factor expressed by the basal bronchial epithelium. The immunohistochemical expression profile of ΔNp63 was evaluated in human bronchial tissue derived from asthma patients. The role of ΔNp63 in apoptosis inhibition and production of soluble mediators was investigated in vitro with cultured BEAS-2B bronchial epithelial cells using molecular biological analysis. In healthy bronchial tissue, ΔNp63-positive basal epithelial cells were covered with differentiated ΔNp63-negative cells but in the asthmatic airway, ΔNp63-positive cells were directly exposed to the bronchial lumen due to severe epithelial shedding. ΔNp63 regulated bronchial apoptosis in response to Toll-like receptor 3 stimulation. On the other hand, expression of ΔNp63 was modulated by stimulation with trypsin and SLIGKV, protease-activated receptor 2 ligands. Further phenotypic analysis revealed that ΔNp63 controlled the transcriptional expression and protein release of some epithelium-derived proinflammatory cytokines and endogenous protease inhibitors. We conclude that ΔNp63 modulates the bronchial epithelial response to viral infection. At the same time, ΔNp63 expression is influenced by proteases, which are abundant in house dust mites. Therefore, the ΔNp63 axis would be intimately involved in these two major triggers of asthma exacerbations, viral infection and protease overload.

T-cell inhibitors for atopic dermatitis

The management of atopic dermatitis is changing with the development of novel biologic agents to target specific molecules in the inflammatory cascade. Following the ability of dupilumab has proved its ability to act on the interleukin 4 receptor in treating atopic dermatitis. Thymic stromal lymphopoietin monoclonal antibody (AMG157/MEDI9929) and OX40 blocking antibody (GBR 830) were developed by targeting the same pathway as dupilumab further upstream. The clinical data on the efficacy for these drugs are not yet known. There is some early evidence that AMG157/MEDI9929 attenuates most measures of allergen-induced asthmatic responses. However, there are no public data on its ability to treat atopic dermatitis. In a phase 2a study, GBR 830 showed at least a 50% reduction in the Eczema Area and Severity Index scores of 17 of 23 patients, but it was not sufficiently powered for identification of statistical differences between GBR 830 versus placebo. Although there is potential for these 2 drugs to greatly improve the management of severe atopic dermatitis, significant clinical trials have not yet been completed to prove efficacy, and there are not yet any available phase 3 clinical trials, which are needed to truly evaluate their efficacy in affecting T-cells.