Immune Dysregulation in the Pathogenesis of Atopic Dermatitis

Inflammatory Skin Diseases: Focus on the Role of Suppressors of Cytokine Signaling (SOCS) Proteins

Inflammatory skin diseases include a series of disorders characterized by a strong activation of the innate and adaptive immune system in which proinflammatory cytokines play a fundamental role in supporting inflammation. Skin inflammation is a complex process influenced by various factors, including genetic and environmental factors, characterized by the dysfunction of both immune and non-immune cells. Psoriasis (PS) and atopic dermatitis (AD) are the most common chronic inflammatory conditions of the skin whose pathogeneses are very complex and multifactorial. Both diseases are characterized by an immunological dysfunction involving a predominance of Th1 and Th17 cells in PS and of Th2 cells in AD. Suppressor of cytokine signaling (SOCS) proteins are intracellular proteins that control inflammatory responses by regulating various signaling pathways activated by proinflammatory cytokines. SOCS signaling is involved in the regulation and progression of inflammatory responses in skin-resident and non-resident immune cells, and recent data suggest that these negative modulators are dysregulated in inflammatory skin diseases such as PS and AD. This review focuses on the current understanding about the role of SOCS proteins in modulating the activity of inflammatory mediators implicated in the pathogenesis of inflammatory skin diseases such as PS and AD.

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

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

Are Antimicrobial Peptides a 21st-Century Solution for Atopic Dermatitis?

Atopic dermatitis (AD) is a chronic inflammatory skin disorder that is the result of various environmental, bacterial and genetic stimuli, which culminate in the disruption of the skin's barrier function. Characterized by highly pruritic skin lesions, xerosis and an array of comorbidities among which skin infections are the most common, this condition results in both a significant loss of quality of life and in the need for life-long treatments (e.g., corticosteroids, monoclonal antibodies and regular antibiotic intake), all of which may have harmful secondary effects. This, in conjunction with AD's rising prevalence, made the development of alternative treatment strategies the focus of both the scientific community and the pharmaceutical industry. Given their potential to both manage the skin microbiome, fight infections and even modulate the local immune response, the use of antimicrobial peptides (AMPs) from more diverse origins has become one of the most promising alternative solutions for AD management, with some being already used with some success towards this end. However, their production and use also exhibit some limitations. The current work seeks to compile the available information and provide a better understanding of the state of the art in the understanding of AMPs' true potential in addressing AD.

TMEM232 promotes the inflammatory response in atopic dermatitis via the nuclear factor-κB and signal transducer and activator of transcription 3 signalling pathways

BACKGROUND

Our group previously found that the transmembrane protein 232 (TMEM232) gene was associated with atopic dermatitis (AD) by genome-wide association study and fine mapping study. However, its function is unclear so far.

OBJECTIVES

To investigate the roles and mechanisms of TMEM232 in AD.

METHODS

The expression of TMEM232 was investigated in skin lesions of patients with AD, the MC903-induced AD mouse model, human primary keratinocytes and immortalized human keratinocyte cell line (HaCaT) cells stimulated with different inflammatory factors. The role of TMEM232 in AD was analysed in HaCaT cells and Tmem232 knockout (Tmem232-/-) mice. Tmem232-specific small interfering RNA (siRNA) was used to evaluate its therapeutic potential in the AD mouse model.

RESULTS

The expression of TMEM232 was significantly increased in skin lesions of patients with AD, the MC903-induced AD mouse model and human primary keratinocytes and HaCaT cells stimulated with different inflammatory factors compared with controls. In the presence of MC903, Tmem232-/- mice exhibited significantly reduced dermatitis severity, mast-cell infiltration in the back, and expression of T-helper (Th)1 and Th2-related inflammatory factors in skin tissue compared with wild-type mice. In vitro and in vivo experiments further showed that upregulation of TMEM232 in AD exacerbated the inflammation response through activating the pathway of nuclear factor-κB and signal transducer and activator of transcription (STAT) 3, and was regulated by the interleukin-4/STAT6 axis, which formed a self-amplifying loop. Finally, topical application of Tmem232 siRNA markedly ameliorated AD-like lesions in the AD model.

CONCLUSIONS

This study is the first to outline the function of TMEM232. It is involved in regulating inflammation in AD and may be a potential target for AD treatment.

Efficacy of probiotics in pediatric atopic dermatitis: A systematic review and meta-analysis

BACKGROUND

Atopic dermatitis (AD) is a prevailing skin disease in childhood. Several studies have appraised probiotics as a strategy for treating AD. We aimed to assess the validity of probiotics in the treatment of AD in children.

METHODS

We systematically searched the PubMed/MEDLINE, Embase, Scopus, EBSCO, Web of Science and Cochrane library databases for randomized controlled trials (RCTs) that assessed the effect of probiotic treatment on SCORAD value in pediatric patients with AD compared with a placebo group between 1 January 2010 and 1 January 2023. The risk of bias and the certainty of evidence were assessed using Cochrane ROB 2.0.

RESULTS

A total of 10 outcomes from 9 RCTs involving 1000 patients were included. Three of these outcomes were analyzed as dichotomous variables in 373 patients. The other seven were analyzed for continuous variables in 627 patients. A meta-analysis of the random-effect model of the dichotomous variables demonstrated no significant difference between the probiotic and control groups [OR = 1.75, 95% confidence interval (CI) (0.70, 4.35), p = 0.23, I²  = 68%]. A meta-analysis of the random-effect model of continuous variables demonstrated significant differences between the probiotic and control groups [MD = -4.24, 95% CI (-7.78, -0.71), p = 0.002, I²  = 71%]. Subgroup analysis of continuous variables showed that the effects of children's age, treatment duration and probiotic species on the SCORAD value were not statistically significant.

CONCLUSION

Evidence on the improvement effect of probiotics on pediatric patients with AD is limited. This study showed that single-strain probiotic treatment exerts a positive effect on AD. Restricted to the quantity and quality of incorporated studies, these conclusions have yet to be validated by high-quality studies.

Integrated transcriptomic and metabolomic analyses of DNCB-induced atopic dermatitis in mice

AIMS

Atopic dermatitis (AD) is a common chronic inflammatory skin disorder that affects up to 20 % of children and 10 % of adults worldwide; however, the exact molecular mechanisms remain largely unknown.

MATERIALS AND METHODS

In this study, we used integrated transcriptomic and metabolomic analyses to study the potential mechanisms of 1-chloro-2,4-dinitrobenzene (DNCB)-induced AD-like skin lesions.

KEY FINDINGS

We found that DNCB induced AD-like skin lesions, including phenotypical and histomorphological alterations and transcriptional and metabolic alterations in mice. A total of 3413 differentially expressed metabolites were detected between DNCB-induced AD-like mice and healthy controls, which includes metabolites in taurine and hypotaurine metabolism, phenylalanine metabolism, biosynthesis of unsaturated fatty acids, tryptophan metabolism, arachidonic acid metabolism, pantothenate and CoA biosynthesis, pyrimidine metabolism, and glycerophospholipid metabolism pathways. Furthermore, the differentially expressed genes associated (DEGs) with these metabolic pathways were analyzed using RNA sequencing (RNA-seq), and we found that the expression of pyrimidine metabolism-associated genes was significantly increased. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that the glycolysis/gluconeogenesis, glucagon signaling pathway and pentose phosphate pathway-associated metabolic genes were dramatically altered.

SIGNIFICANCE

Our results explain the possible mechanism of AD at the gene and metabolite levels and provide potential targets for the development of clinical drugs for AD.

WFDC12-overexpressing contributes to the development of atopic dermatitis via accelerating ALOX12/15 metabolism and PAF accumulation

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by eczema-like skin lesions, dry skin, severe itching, and recurrent recurrence. The whey acidic protein four-disulfide core domain gene WFDC12 is highly expressed in skin tissue and up-regulated in the skin lesions of AD patients, but its role and relevant mechanism in AD pathogenesis have not been studied yet. In this study, we found that the expression of WFDC12 was closely related to clinical symptoms of AD and the severity of AD-like lesions induced by DNFB in transgenic mice. WFDC12-overexpressing in the epidermis might promote the migration of skin-presenting cells to lymph nodes and increase Th cell infiltration. Meanwhile, the number and ratio of immune cells and mRNA levels of cytokines were significantly upregulated in transgenic mice. In addition, we found that ALOX12/15 gene expression was upregulated in the arachidonic acid metabolism pathway, and the corresponding metabolite accumulation was increased. The activity of epidermal serine hydrolase decreased and the accumulation of platelet-activating factor (PAF) increased in the epidermis of transgenic mice. Collectively, our data demonstrate that WFDC12 may contribute to the exacerbation of AD-like symptoms in DNFB-induced mouse model by enhancing arachidonic acid metabolism and PAF accumulation and that WFDC12 may be a potential therapeutic target for human atopic dermatitis.

Red Ginseng Extract and γ-Aminobutyric Acid Synergistically Enhance Immunity Against Cancer Cells and Antitumor Metastasis Activity in Mice

The effects of combined administration of red ginseng (RG) extracts and gamma-aminobutyric acid (GABA) on immunostimulatory activity and tumor metastasis inhibition were investigated in mice. For the immunostimulatory activity, splenocyte proliferation, natural killer (NK) cell activity, including the production of granzyme B (GrB) and interferon gamma (IFN-γ), and serum level of cytokine such as IFN-γ, interleukin (IL)-17, and IL-21 were assessed. Peyer's patch cells obtained from mice administered with RG+GABA were cultured, and the cytokine level in the culture supernatant and bone marrow (BM) cell proliferation activity were examined. The proliferative activity of splenocytes was significantly higher in the RG-GABA treatment group than in RG or GABA alone (P < .05). In the experimental tumor metastasis model, oral administration of RG+GABA showed a higher antitumor metastatic effect compared to that of RG or GABA alone. Oral administration of RG+GABA significantly augmented NK cell-mediated cytotoxicity against YAC-1 tumor cells. In addition, the production of GrB and IFN-γ was stimulated in the culture supernatant of NK cells and YAC-1 cells. Serum concentrations of IFN-γ, IL-17, and IL-21 in mice with RG+GABA were significantly higher compared to the corresponding blood levels in mice administered with RG or GABA alone. The RG+GABA group showed significant BM cell proliferation and increased production of IL-6 and granulocyte-macrophage colony-stimulating factor compared to that in the monotherapy groups. Therefore, RG may have a synergistic effect with GABA for enhancing the host defense system such as BM proliferation and NK cell activity in a tumor metastasis model.

Effects of Echinocystic Acid on Atopic Dermatitis and Allergic Inflammation of the Skin and Lungs

BACKGROUND

Echinocystic acid (ECA), a pentacyclic triterpene enriched in various herbs, promotes anti-inflammatory and antioxidant activity; however, its therapeutic effects on atopic dermatitis (AD) or atopic march and the underlying mechanisms of action have not yet been fully elucidated.

PURPOSE

This study aimed to elucidate the effects and molecular mechanisms of ECA on AD and allergic inflammation.

METHODS

We evaluated the inhibitory effects of ECA using a house dust mite (HDM)-induced AD mouse model and human keratinocytes.

RESULTS

The results revealed that ECA improved AD symptoms by decreasing epidermal/dermal thickness, immune cell infiltration, and restoring skin barrier function, as well as an imbalanced immune response. In addition, repeated epicutaneous HDM challenges aggravated allergic inflammation in mice lungs, which was caused by the infiltration of immune cells and collagen deposition, whereas ECA alleviated these symptoms. Moreover, ECA suppressed the expression of T helper cell-derived cytokines, phosphorylation of extracellular signal-regulated kinase, and signal transducer and activator of transcription 1 in the skin and lungs of mice with HDM-induced AD, as well as inhibited the translocation of nuclear factor-κB in HaCaT keratinocytes.

CONCLUSION

This is the meaningful study to demonstrate that ECA improves allergic inflammation of the skin and lungs through recovery of the skin barrier, regulation of immune balance, and alleviation of lung inflammation, suggesting that ECA has therapeutic potential as an antiatopic and antiallergic agent that blocks the progression of AD to atopic march.

An Overview of the Latest Metabolomics Studies on Atopic Eczema with New Directions for Study

Atopic eczema (AE) is an inflammatory skin disorder affecting approximately 20% of children worldwide and early onset can lead to asthma and allergies. Currently, the mechanisms of the disease are not fully understood. Metabolomics, the analysis of small molecules in the skin produced by the host and microbes, opens a window to observe the mechanisms of the disease which then may lead to new drug targets for AE treatment. Here, we review the latest advances in AE metabolomics, highlighting both the lipid and non-lipid molecules, along with reviewing the metabolites currently known to reside in the skin.

Potential Natural Biomolecules Targeting JAK/STAT/SOCS Signaling in the Management of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease caused by the dysregulation of cytokines and other immune mediators. JAK/STAT is a classical signal transduction pathway involved in various biological processes, and its dysregulation contributes to the key aspects of AD pathogenesis. Suppressor of cytokine signaling (SOCS) proteins negatively regulate the immune-related inflammatory responses mediated by the JAK/STAT pathway. JAK/STAT-mediated production of cytokines including IL-4, IL-13, IL-31, and TSLP inhibits the expression of important skin barrier proteins and triggers pruritus in AD. The expression of SOCS proteins regulates the JAK-mediated cytokines and facilitates maintaining the skin barrier disruptions seen in AD. STATs are crucial in dendritic-cell-activated Th2 cell differentiation in the skin, releasing inflammatory cytokines, indicating that AD is a Th2-mediated skin disorder. SOCS proteins aid in balancing Th1/Th2 cells and, moreover, regulate the onset and maintenance of Th2-mediated allergic responses by reducing the Th2 cell activation and differentiation. SOCS proteins play a pivotal role in inflammatory cytokine-signaling events that act via the JAK/STAT pathway. Therapies relying on natural products and derived biomolecules have proven beneficial in AD when compared with the synthetic regimen. In this review, we focused on the available literature on the potential natural-product-derived biomolecules targeting JAK/STAT/SOCS signaling, mainly emphasizing the SOCS family of proteins (SOCS1, SOCS3, and SOCS5) acting as negative regulators in modulating JAK/STAT-mediated responses in AD pathogenesis and other inflammatory disorders.

Anti-inflammatory effects of Eclipta prostrata Linné on house dust mite-induced atopic dermatitis in vivo and in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Atopic dermatitis (AD) is a kind of inflammation on the skin following with swollen, itchy, dryness and cracked skin. Though the exact cause of AD is unknown, there are evidence that people with AD have a compromised skin barrier along with inflammation. Eclipta prostrata Linné is a traditional herbal medicinal plant, has been used for the diabetes, obesity, jaundice, and inflammation. We supposed E. prostrata L. has an anti-inflammatory effect on the skin.

AIM OF THE STUDY

We aimed to assess the effect of E. prostrata L. EtOH extract (EP) and elucidate the associated molecular mechanisms.

MATERIALS AND METHODS

The effect of EP and the molecular mechanisms were eluciated in house dust mite (HDM)-induced AD mice model and TNF-α/IFN-γ-stimulated HaCaT keratinocytes by histological analysis, enzyme-linked immunosorbent assay, quantitative real time polymerase chain reaction, and Western blot.

RESULTS

The results revealed that EP improved the progression of AD symptoms, decreasing epidermis/dermis thickness, infiltrated immune cells, and restored the skin barrier dysfunction and imbalanced immune response. EP suppressed the expressions of T helper (Th)1, Th2, Th17 cytokines, phosphorylation of extracellular signal-regulated kinase/signal transducer and activator of transcription 1 in skin of HDM-induced AD mice as well as inhibition the translocation of nuclear factor-κB in HaCaT keratinocytes.

CONCLUSIONS

Collectively, EP improved the allergic inflammation of the skin through recovery the skin barrier, and regulation the immune balance. These results suggest EP may have therapeutic potential as an anti-atopic agent.

The risk of atopic dermatitis may be affected by IL-1B +3954 C/T and IL-18 -137G/C polymorphisms: evidence from a meta-analysis

Introduction

Whether Th1-related cytokine polymorphisms influence the risk of atopic dermatitis (AD) remain inconclusive.

Aim

The authors performed a meta-analysis to robustly explore relationships between Th1-related cytokine polymorphisms and the risk of AD by merging the results of eligible publications.

Material and methods

The authors strictly adhere to the PRISMA guidelines in study design and implementation. A thorough literature search in Medline, Embase, Wanfang, VIP and CNKI was performed by the authors to identify eligible publications. Relationships between TNF-α/IL-1/IL-6/IL-18 polymorphisms and the risk of AD were estimated with odds ratio and its 95% confidence interval. The statistically significant p value was set at 0.05. The quality of eligible publications was assessed by the Newcastle-Ottawa scale (NOS).

Results

In total twenty-one publications with a NOS score of 7-8 were selected for merged quantitative analyses. We have noticed that genotypic frequencies of IL-1B +3954 C/T and IL-18 -137G/C polymorphisms among cases with AD and population-based controls differed significantly. Moreover, we have found that genotypic frequency of IL-1B +3954 C/T polymorphism among cases with AD and population-based controls of Caucasian origin differed significantly, and genotypic frequency of IL-18 -137G/C polymorphism among cases with AD and population-based controls of both Caucasian and Asian origins also differed significantly. However, we did not observe such genotypic distribution differences for TNF-α -238 G/A, TNF-α -308 G/A, IL-1A -889 C/T, IL-1B −511 C/T and IL6 -174 G/C polymorphisms.

Conclusions

The present meta-analysis shows that IL-1B +3954 C/T and IL-18 -137G/C polymorphisms may affect the risk of AD.

IL-31 and IL-31 receptor expression in acute experimental canine atopic dermatitis skin lesions

BACKGROUND

To optimise the interleukin (IL)-31-blocking therapy in atopic dermatitis (AD), an understanding of the chronology in the expression of IL-31 and its receptor (IL-31RA) is needed.

HYPOTHESIS/OBJECTIVES

(i) To assess the chronological expression of IL-31 in canine AD skin lesions, (ii) to compare it with serum IL-31 levels and macroscopic skin lesion scores, and (iii) to determine the identity of IL-31- and IL-31RA-positive cells.

ANIMALS

Four atopic dogs sensitised to house dust mites.

METHODS AND MATERIALS

Skin and blood samples were obtained 0 h, 24 h, 48 and 96 h after allergen provocation. IL-31 and IL-31RA single-staining immunofluorescence (IF), as well as IL-31/CD3, IL-31/CD4 and IL-31RA/β3-tubulin double-staining IF were performed. The IL-31-positive cells were counted subjectively.

RESULTS

The peak IL-31 expression for three of four dogs occurred 24 h or 48 h postchallenge; it started to decrease at 96 h. There was no significant correlation between the IL-31 expression scores and the serum IL-31 concentrations or the macroscopic skin lesion scores (P = 0.35 and P = 0.36, respectively). The majority of IL-31-positive cells were positive for CD3 (range 91-100%) and CD4 (range 63-100%), indicating that they were helper T (Th) cells. Unexpectedly, sebaceous glands were strongly immunolabelled with IL-31; the extinction of this positivity after immunoabsorption with IL-31 further supported the validity of this immunostaining. The IL-31RA was visualised on keratinocytes and a small proportion of dermal nerves.

CONCLUSIONS AND CLINICAL IMPORTANCE

The early and transient production of IL-31 by Th cells supports the concept of using IL-31 inhibiting strategies as a proactive therapy to prevent flares of AD skin lesions.

The Role of Cord Blood in the Regulation of the Cellular and Humoral Link of Immunity in Experimental Atopic Dermatitis

Background. Atopic dermatitis (AD) as one of the most common diseases of autoimmune genesis in the structure of dermatological practice, is characterized by itching, dryness, thickening of the skin, characteristic rashes. The drugs of choice in the treatment of AD are steroidal anti-inflammatory drugs. However, the development of unwanted side effects is a serious problem attributed to using hormone therapy. The search for effective methods of treating AD is an urgent task of medicine and in particular dermatology. At the same time, there is an obvious need for the participation in the solution of this problem also of specialists-immunologists working in the field of application of cell therapy drugs, acting on various pathogenetic links of the disease. The development of new or optimization of existing methods of treating AD is the urgent task facing them. Objective. Evaluation of the immunocorrective effect of lyophilized (lHCBL) and cryopreserved human cord blood leucoconcetrate (cHCBL) on a AD model. Methods. The experiments were carried out on 6-month-old Wistar rats. Upon induction of AD, the inflammation focus was formed on the rat's back (9–10 cm2) by daily rubbing in a 5% alcohol-acetone solution of dinitrochlorobenzene (DNCB) for 21 days. cHCBL and lHCBL were injected intraperitoneally, 0.5 ml at a dose of 5´106 cells in one day after the final DNCB treatment. The adhesive and phagocytic activity of the cells of the peritoneal cavity, the level of circulating immune complexes, the population and subpopulation of lymphocytes (CD3+, CD4+, CD8+, CD16+, CD4+CD25+), the immunoregulatory index of lymphocytes, the concentration of immunoglobulins in the blood serum were determined. Results. For AD induced by DNCB, systemic changes in the immune status are characteristic, which is expressed by changes in the parameters of cellular and humoral immunity. The most fundamental changes in cell subpopulations in spleen of rats with AD were revealed: a decrease in the number of total T-lymphocytes and their two main subpopulations (CD4+ and CD8+ cells). Against this background, changes were noted in the monocytic-phagocytic and humoral systems of immunity. The paper shows the effectiveness of the use of cHCBL and lHCBL in the correction of pathological manifestations of experimental AD. On the background of treatment, the features of the immunocorrective effect of each of the drugs were noted. Thus, when assessing intergroup values, a more pronounced increase in T-reg was revealed in rats of the 5th group – 3.9 [3.8; 4.0] versus 3.2 [3.0; 3.3] in the 4th group (P < 0.01); IgA level – 1.6 [1.5; 1.7] versus 1.3 [1.2; 1.4] (P < 0.01). Conclusions. Thus, lHCBL exhibits immunocorrective activity in the treatment of experimental AD, surpassing in some parameters the activity of сHCBL, which is promising for its use in clinical practice.

The Epidemiology and Global Burden of Atopic Dermatitis: A Narrative Review

The global epidemiology of atopic dermatitis (AD) in the current decade (2009-2019) has not been extensively reported. Epidemiological studies play an important role in presenting the risk factors of AD, as detailed prevalence and incidence data could demonstrate the burden of disease in the population of adults, adolescents, and children in different geographical regions. Thus, the primary objective of this review was to assess and summarize the epidemiological studies of the prevalence and incidence of AD in different age groups, focusing on data from studies published for 2009 to 2019. After a thorough literature search, six countries were identified from African, Asian, and European regions respectively, who published studies on AD. In contrast, only two studies were identified from Australia and New Zealand, three countries from North America and two from South America published AD studies, respectively. The highest prevalence of AD from included studies was noted among Swedish children with 34%, while the lowest prevalence was in Tunisian children with 0.65%; studies reporting incidence data were far less numerous. A common trend in the prevalence of AD was that children would have a higher prevalence as compared to adolescents and adults. The severity and morbidity of the disease showed variance with age, sex, socioeconomic characteristics, geographical location, and ethnicity. Environmental factors played an important role as causative agents in AD. The risk factors that were proven to cause and induce AD were skin barrier impairments due to FLG mutation, changes in the environment, and diet. FLG mutation may impair the skin barrier function by disruption of pH and hydration maintenance of the skin. Lastly, there were only a few studies on the incidence of AD in the 21st century. Therefore, epidemiological studies on childhood and adulthood AD in different continents are still needed, especially on the incidence of AD during adulthood.

Autoimmunity as an Etiological Factor of Cancer: The Transformative Potential of Chronic Type 2 Inflammation

Recent epidemiological studies have found an alarming trend of increased cancer incidence in adults younger than 50 years of age and projected a substantial rise in cancer incidence over the next 10 years in this age group. This trend was exemplified in the incidence of non-cardia gastric cancer and its disproportionate impact on non-Hispanic white females under the age of 50. The trend is concurrent with the increasing incidence of autoimmune diseases in industrialized countries, suggesting a causal link between the two. While autoimmunity has been suspected to be a risk factor for some cancers, the exact mechanisms underlying the connection between autoimmunity and cancer remain unclear and are often controversial. The link has been attributed to several mediators such as immune suppression, infection, diet, environment, or, perhaps most plausibly, chronic inflammation because of its well-recognized role in tumorigenesis. In that regard, autoimmune conditions are common causes of chronic inflammation and may trigger repetitive cycles of antigen-specific cell damage, tissue regeneration, and wound healing. Illustrating the connection between autoimmune diseases and cancer are patients who have an increased risk of cancer development associated with genetically predisposed insufficiency of cytotoxic T lymphocyte-associated protein 4 (CTLA4), a prototypical immune checkpoint against autoimmunity and one of the main targets of cancer immune therapy. The tumorigenic process triggered by CTLA4 insufficiency has been shown in a mouse model to be dependent on the type 2 cytokines interleukin-4 (IL4) and interleukin-13 (IL13). In this type 2 inflammatory milieu, crosstalk with type 2 immune cells may initiate epigenetic reprogramming of epithelial cells, leading to a metaplastic differentiation and eventually malignant transformation even in the absence of classical oncogenic mutations. Those findings complement a large body of evidence for type 1, type 3, or other inflammatory mediators in inflammatory tumorigenesis. This review addresses the potential of autoimmunity as a causal factor for tumorigenesis, the underlying inflammatory mechanisms that may vary depending on host-environment variations, and implications to cancer prevention and immunotherapy.

Differences in gut microbiota between allergic rhinitis, atopic dermatitis, and skin urticaria: A pilot study

INTRODUCTION

Several forms of allergy have been clinically presented, including, among others, atopic dermatitis (eczema), urticaria (hives), and allergic rhinitis (rhinitis). As their detailed pathogenesis continues to be researched, we aimed in the current study to compare gut microbiota differences between eczema, hives, and rhinitis patients.

METHODS

We enrolled 19 eczemas, nine hives, and 11 allergic rhinitis patients in this study. Fecal samples were examined using 16S ribosomal ribonucleic acid amplicon sequencing, followed by bioinformatics and statistical analyses. We compared microbiota in dermatitis (eczema), chronic urticaria (hives), and allergic rhinitis (rhinitis).

RESULTS

All clinical data were similar between the subgroups. The microbiota results indicated that Bacteroidales species were found in skin allergies, both urticaria and eczema, when compared to rhinitis. The microbiota differs substantially between those patients with atopic dermatitis (eczema), chronic urticaria (hives), and allergic rhinitis (rhinitis), thus indicating that the gut-skin and gut-nose axes exist. Gut flora colonies differ significantly between skin allergy and nose allergy. Bacteroidales species could be a clinical link between gut flora and skin allergy; of those, Bacteroids Plebeius DSM 17135 is significantly associated with the urticaria (hives) subgroup.Conclusion. Our results demonstrated high intra-group homogeneous and high inter-group heterogeneous microbiota. The clinical symptoms of eczema, hives, and rhinitis can all be linked to specific microbiota in the current study. In this pilot study, the Ruminococcaceae and Bacteroidales species are associated with allergic disease, in line with several previous published articles, and the abundance of Firmicutes Phylum is representative of intestinal dysbiosis. In the future, a larger cohort and thorough biochemical studies are needed for confirmation.

Fe2+: Fe3+ Molar Ratio Influences the Immunomodulatory Properties of Maghemite (γ-Fe2O3) Nanoparticles in an Atopic Dermatitis Model

Here, we report the different antioxidant and physiological effects of maghemite nanoparticles (γ-Fe2O3 NPs) obtained using various Fe2+: Fe3+ molar ratios (FM1 = 1: 1, FM2 = 1: 2, and FM3 = 2: 3) via coprecipitation from ferrous/ferric salts. We investigated the physical, optical, and antioxidant properties of FM1, FM2, and FM3 nanoparticles by conducting UV, Raman, FTIR, and EDX spectroscopic analyses along with DPPH radical scavenging activity. Results showed the highest DPPH scavenging activity in the FM2 group (50.76%), while the activity in the FM1 and FM3 groups was 23.60% and 34.63%, respectively. In addition, topical application of nanoparticles induced significant but different anti-inflammatory and immunomodulatory effects in Dermatophagoides farinae extract/2,4-dinitrochlorobenzene (DFE/DNCB)-sensitized BALB/c mice. The FM2 treatment alleviates more effectively the DFE/DNCB-induced atopic dermatitis-like (AD-like) symptoms in mouse ears (edema, excoriation, scaling, and hemorrhage). In comparison with the DFE/DNCB-sensitized mice, FM2 treatment greatly reduced the size and weight of the spleen and the lymph nodes. It also suppressed mast cell infiltration (2-fold) and reduced dermal and epidermal thickness in mice. In addition, FM2 treatment exhibited better inhibition of the mRNA levels of Th1 (IFN-γ and TNF-α) and Th2 cytokines (IL-4, IL-5, IL-6, IL-10, IL-13, and IL-31), as well as the levels of various inflammation-related proteins (COX-2, iNOS, and TNF-α). Moreover, we demonstrated that an increasing proportion of Fe3+ in Fe2+: Fe3+ enhances the antioxidant activity and increases the anti-inflammatory and immunomodulatory effects of γ-Fe2O3 NPs in an AD mouse model. Thus, γ-Fe2O3 NPs could be used in the formulation of nonsteroidal drugs for AD treatment.

Design, synthesis and biological evaluation of novel benzoxaborole derivatives as potent PDE4 inhibitors for topical treatment of atopic dermatitis

In this work, a series of structurally novel benzoxaborole derivatives were designed, synthesized and biologically evaluated as PDE4 inhibitors for battling atopic dermatitis (AD). Among them, the majority exhibited superior PDE4B inhibitory activities to that of the lead compound Crisaborole, an approved PDE4 inhibitor. In particular, 72, the most potent PDE4B inhibitor throughout this series, displayed 136-fold improved enzymatic activity (IC₅₀ = 0.42 nM) as compared to Crisaborole (IC₅₀ = 57.20 nM), along with favorable isoform specificity. In the phorbol ester (PMA)-induced mouse ear oedema model, 72 exerted remarkably greater efficacy than Crisaborole at the same dosage (P < 0.05). Moreover, the ointment of 72 exerted dramatically enhanced therapeutic potency than the ointment of Crisaborole (P < 0.05) in the calcipotriol-induced mouse AD model. In addition to the potent in vitro and in vivo activity, 72 displayed favorable safety in the repeated oral dose toxicity study and did not exhibit phototoxicity. With the above attractive biological performance, 72 is worthy of further functional investigation as a novel anti-AD therapeutic agent.

Galectin-9 Induced by Dietary Prebiotics Regulates Immunomodulation to Reduce Atopic Dermatitis Symptoms in 1-Chloro-2,4-Dinitrobenzene (DNCB)-Treated NC/Nga Mice

Atopic dermatitis (AD) is a skin disorder that causes chronic itch. We investigated the inhibitory effects of a mixture of prebiotic short-chain galacto-oligosaccharides and long-chain fructooligosaccharides (scGOS/lcFOS), inulin, or β-glucan on AD development in 1-chloro-2,4- dinitrobenzene (DNCB)-treated NC/Nga mice. Mice were randomly assigned to six groups: untreated mice, AD control, positive control (DNCB-treated NC/Nga mice fed a dietary supplement of Zyrtec), and DNCB-treated NC/Nga mice fed a dietary supplement of prebiotics such as scGOS/lcFOS (T1), inulin (T2), or β-glucan (T3). The prebiotic treatment groups (T1, T2, and T3) showed suppression of AD symptoms, Th2 cell differentiation, and AD-like skin lesions induced by DNCB. In addition, prebiotic treatment also reduced the number of microorganisms such as Firmicutes, which is associated with AD symptoms, and increased the levels of Bacteroidetes and Ruminococcaceae, which are associated with alleviation of AD symptoms. Our findings demonstrate the inhibitory effects of prebiotics on AD development by improving the Th1/Th2 cytokine balance and beneficial symbiotic microorganisms in in vitro and in vivo models.

Which Way Do We Go? Complex Interactions in Atopic Dermatitis Pathogenesis

Atopic dermatitis (AD) is a common, chronic, inflammatory skin condition characterized by recurrent and pruritic skin eruptions. Multiple factors contribute to the pathogenesis of AD, including skin barrier dysfunction, microbial dysbiosis, and immune dysregulation. Interactions among these factors form a complex, multidirectional network that can reinforce atopic skin disease but can also be ameliorated by targeted therapies. This review summarizes the complex interactions among contributing factors in AD and the implications on disease development and therapeutic interventions.

Biotherapeutic Approaches in Atopic Dermatitis

The skin microbiome plays a central role in inflammatory skin disorders such as atopic dermatitis (AD). In AD patients, an imbalance between pathogenic Staphylococcus aureus (S. aureus) and resident skin symbionts creates a state of dysbiosis which induces immune dysregulation and impairs skin barrier function. There are now exciting new prospects for microbiome-based interventions for AD prevention. In the hopes of achieving sustained control and management of disease in AD patients, current emerging biotherapeutic strategies aim to harness the skin microbiome associated with health by restoring a more diverse symbiotic skin microbiome, while selectively removing pathogenic S. aureus. Examples of such strategies are demonstrated in skin microbiome transplants, phage-derived anti-S. aureus endolysins, monoclonal antibodies, and quorum sensing (QS) inhibitors. However, further understanding of the skin microbiome and its role in AD pathogenesis is still needed to understand how these biotherapeutics alter the dynamics of the microbiome community; to optimize patient selection, drug delivery, and treatment duration; overcome rapid recolonization upon treatment cessation; and improve efficacy to allow these therapeutic options to eventually reach routine clinical practice.

Epicutaneous sensitization to food allergens in atopic dermatitis: What do we know?

Atopic dermatitis (AD) is a chronic inflammatory skin disease mainly affecting children, which has no definitive curative therapy apart from natural outgrowing. AD is persistent in 30%-40% of children. Epithelial barrier dysfunction in AD is a significant risk factor for the development of epicutaneous food sensitization, food allergy, and other allergic disorders. There is evidence that prophylactic emollient applications from birth may be useful for primary prevention of AD, but biomarkers are needed to guide cost-effective targeted therapy for high-risk individuals. In established early-onset AD, secondary preventive strategies are needed to attenuate progression to other allergic disorders such as food allergy, asthma, and allergic rhinitis (the atopic march). This review aims to describe the mechanisms underpinning the development of epicutaneous sensitization to food allergens and progression to clinical food allergy; summarize current evidence for interventions to halt the progression from AD to food sensitization and clinical food allergy; and highlight unmet needs and directions for future research.

miRNAs as Therapeutic Targets in Inflammatory Disease

In the past decade, we have witnessed considerable developments in understanding the roles and functions of miRNAs. In parallel, the identification of alterations in miRNA expression in inflammatory disease indicates their potential as therapeutic targets. Pharmacological treatments targeting abnormally expressed miRNAs for inflammatory diseases are not yet in clinical practice; however, some small compounds and nucleic acids targeting miRNAs have shown promise in preclinical development. Here, we focus on recent advances in understanding miRNA deregulation in inflammatory diseases and provide an overview of the current development of miRNA-based therapeutics in these diseases with an emphasis on newly discovered miRNA therapeutic targets.

Fucoidan from seaweed Fucus vesiculosus inhibits 2,4-dinitrochlorobenzene-induced atopic dermatitis

Fucoidan, one activator of scavenger receptor class A (SR-A), plays important roles in a variety of biological activities, including anti-inflammatory, antioxidant, and antitumor actions. However, the effects of fucoidan on atopic dermatitis (AD) have not been elucidated. To assess this, 2,4-dinitrofluorobenzene (DNFB)-treated BALB/c mice were painted with fucoidan. Results showed that fucoidan significantly ameliorated ear swelling, improved abdomen skin lesions, and decreased inflammatory cell infiltration. In addition, fucoidan significantly suppressed the serum levels of IgE and IL-4 in DNFB-induced AD mice. The infiltration of CD4+ T cells in skin lesions and spleen was also reduced in fucoidan-treated AD mice. Furthermore, treatment with fucoidan promoted Treg cells but attenuated Th1/17 response in the spleens from DNFB-induced AD mice. Together, these results suggest that fucoidan, a natural seaweed-rich polysaccharide, has a potential therapeutic efficacy in the treatment of AD, correlates with the induction of higher anti-inflammatory response through inducing Treg cells.

Cannabinoid Signaling in the Skin: Therapeutic Potential of the "C(ut)annabinoid" System

The endocannabinoid system (ECS) has lately been proven to be an important, multifaceted homeostatic regulator, which influences a wide-variety of physiological processes all over the body. Its members, the endocannabinoids (eCBs; e.g., anandamide), the eCB-responsive receptors (e.g., CB₁, CB₂), as well as the complex enzyme and transporter apparatus involved in the metabolism of the ligands were shown to be expressed in several tissues, including the skin. Although the best studied functions over the ECS are related to the central nervous system and to immune processes, experimental efforts over the last two decades have unambiguously confirmed that cutaneous cannabinoid ("c[ut]annabinoid") signaling is deeply involved in the maintenance of skin homeostasis, barrier formation and regeneration, and its dysregulation was implicated to contribute to several highly prevalent diseases and disorders, e.g., atopic dermatitis, psoriasis, scleroderma, acne, hair growth and pigmentation disorders, keratin diseases, various tumors, and itch. The current review aims to give an overview of the available skin-relevant endo- and phytocannabinoid literature with a special emphasis on the putative translational potential, and to highlight promising future research directions as well as existing challenges.

Proactive maintenance therapy of canine atopic dermatitis with the anti-IL-31 lokivetmab. Can a monoclonal antibody blocking a single cytokine prevent allergy flares?

BACKGROUND

Once the signs of canine atopic dermatitis (AD) are controlled, the proactive application of topical glucocorticoids can delay disease flares.

OBJECTIVES

We wished to determine if the proactive administration of the anti-IL-31 lokivetmab would prevent or delay flares of canine AD.

ANIMALS

We tested this strategy in four Maltese-beagle atopic dogs before enrolling 21 dogs with spontaneous AD.

METHODS AND MATERIALS

In our acute AD model, house dust mite (HDM)-sensitized dogs were injected once with lokivetmab. After seven days, an HDM suspension was applied epicutaneously, and both skin lesions and pruritus manifestations were quantified for 24 h. In a second study, 21 dogs with spontaneous AD controlled with anti-allergic drugs were treated with lokivetmab per manufacturer's recommendations; all anti-allergic drugs were discontinued within four weeks after the first injection. All dogs were followed prospectively for at least one year and the time-to-flare (TTF) of AD after the last day of anti-allergic treatment was determined.

RESULTS

In the experimental study, one injection of lokivetmab prevented nearly all expected allergen-induced pruritus manifestations but not skin lesion development. In dogs with spontaneous AD, the median TTF after lokivetmab proactive therapy was 63 days. One-fourth of dogs did not exhibit a flare for at least one year while receiving lokivetmab monotherapy.

CONCLUSIONS

Although lokivetmab seems more effective to prevent pruritus than skin lesions in dogs with experimental AD' it also can delay disease flares in some dogs with the spontaneous disease. Studies are needed to identify those patients most likely to respond to such a proactive regimen.

Cat Allergy as a Source Intensification of Atopic Dermatitis in Adult Patients

Atopic dermatitis (AD) is characterized by exacerbations and remissions of eczematous skin, underlain by impaired skin barrier and aberrant Th2-type and Th-22 cytokine production. A number of allergens, in particular contact with fur animals, may aggravate the disease. This study seeks to define the influence of having a regular contact with a pet cat at home on the severity of symptoms and signs of AD. We addressed the issue using the SCORing Atopic Dermatitis (SCORAD) and visual analog (VAS) scores to assess the intensity of pruritus and by measuring the blood content of specific IgE and IL-4, IL-13, and IL-22 cytokines. The study group consisted of 47 adult patients suffering from AD since childhood, 18 of whom declared having regular contact with a cat and the remaining 29 who denied it. There also was a control group consisted of 16 healthy volunteers with no AD signs. The SCORAD and VAS scores were significantly higher in patients in contact with a cat than in those without it (median SCORAD 61.0 vs. 50.4 and VAS 9.0 vs. 4.0 points, respectively). The sIgE of a majority of patients (94.4%) in contact with a cat was in Class V-VI, compared with just a few patients (3.4%) with no such contact, having sIgE in the same classes (p < 0.001). Significant correlations were revealed between SCORAD and VAS scores and the class level of serum sIgE value. In addition, IL-22 was a single elevated cytokine, only in the patients in contact with a cat, and it correlated with pruritus severity. The results of the study underline the need to beware of the cat fur allergen, and they stress forethought and caution in acquiring and keeping a pet cat by patients suffering from AD.