Gene expression is differently affected by pimecrolimus and betamethasone in lesional skin of atopic dermatitis

Bilayered skin equivalent mimicking psoriasis as predictive tool for preclinical treatment studies

Psoriasis is a prevalent, inflammatory skin disease without cure. Further research is required to unravel dysregulated processes and develop new therapeutic interventions. The lack of suitable in vivo and in vitro preclinical models is an impediment in the psoriasis research. Recently, the development of 3D skin models has progressed including replicas with disease-like features. To investigate the use of in vitro models as preclinical test tools, the study focused on treatment responses of 3D skin replicas. Cytokine-priming of skin organoids induced psoriatic features like inflammation, antimicrobial peptides (AMP), hyperproliferation and impaired differentiation. Topical application of dexamethasone (DEX) or celastrol (CEL), a natural anti-inflammatory compound reduced the secretion of pro-inflammatory cytokines. DEX and CEL decreased the gene expression of inflammatory mediators. DEX barely affected the psoriatic AMP transcription but CEL downregulated psoriasis-driven AMP genes. Subcutaneous application of adalimumab (ADM) or bimekizumab (BMM) showed anti-psoriatic effects via protein induction of the differentiation marker keratin-10. Dual blockage of TNF-α and IL-17A repressed the inflammatory psoriasis phenotype. BMM inhibited the psoriatic expression of AMP genes and induced KRT10 and cell-cell contact genes. The present in vitro model provides a 3D environment with in vivo-like cutaneous responses and represents a promising tool for preclinical investigations.

Integrating multi-omics approaches in deciphering atopic dermatitis pathogenesis and future therapeutic directions

Atopic dermatitis (AD), a complex and heterogeneous chronic inflammatory skin disorder, manifests in a spectrum of clinical subtypes. The application of genomics has elucidated the role of genetic variations in predisposing individuals to AD. Transcriptomics, analyzing gene expression alterations, sheds light on the molecular underpinnings of AD. Proteomics explores the involvement of proteins in AD pathophysiology, while epigenomics examines the impact of environmental factors on gene expression. Lipidomics, which investigates lipid profiles, enhances our understanding of skin barrier functionalities and their perturbations in AD. This review synthesizes insights from these omics approaches, highlighting their collective importance in unraveling the intricate pathogenesis of AD. The review culminates by projecting future trajectories in AD research, particularly the promise of multi-omics in forging personalized medicine and novel therapeutic interventions. Such an integrated multi-omics strategy is poised to transform AD comprehension and management, steering towards more precise and efficacious treatment modalities.

Atopic dermatitis-associated genetic variants regulate LOC100294145 expression implicating interleukin-27 production and type 1 interferon signaling

Background

Atopic dermatitis (AD) is a complex inflammatory disease with a strong genetic component. A singular approach of genome wide association studies (GWAS) can identify AD-associated genetic variants, but is unable to explain their functional relevance in AD. This study aims to characterize AD-associated genetic variants and elucidate the mechanisms leading to AD through a multi-omics approach.

Methods

GWAS identified an association between genetic variants at 6p21.32 locus and AD. Genotypes of 6p21.32 locus variants were evaluated against LOC100294145 expression in peripheral blood mononuclear cells (PBMCs). Their influence on LOC100294145 promoter activity was measured in vitro via a dual-luciferase assay. The function of LOC100294145 was then elucidated through a combination of co-expression analyses and gene enrichment with g:Profiler. Mendelian randomization was further used to assess the causal regulatory effect of LOC100294145 on its co-expressed genes.

Results

Minor alleles of rs116160149 and rs115388857 at 6p21.32 locus were associated with increased AD risk (p = 2.175 × 10-8, OR = 1.552; p = 2.805 × 10-9, OR = 1.55) and higher LOC100294145 expression in PBMCs (adjusted p = 0.182; 8.267 × 10-12). LOC100294145 expression was also found to be increased in those with AD (adjusted p = 3.653 × 10-2). The genotype effect of 6p21.32 locus on LOC100294145 promoter activity was further validated in vitro. Co-expression analyses predicted LOC100294145 protein's involvement in interleukin-27 and type 1 interferon signaling, which was further substantiated through mendelian randomization.

Conclusion

Genetic variants at 6p21.32 locus increase AD susceptibility through raising LOC100294145 expression. A multi-omics approach enabled the deduction of its pathogenesis model comprising dysregulation of hub genes involved in type 1 interferon and interleukin 27 signaling.

Inhibition of gasdermin D (GSDMD) as a promising therapeutic approach for atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by pruritus, erythema, and skin barrier dysfunction. Gasdermin D (GSDMD) is the key executioner of an inflammatory cell death mechanism known as pyroptosis. However, the role of GSDMD in the pathogenesis of AD remains unclear. Through the analysis of publicly available Gene Expression Omnibus (GEO) datasets, we observed an upregulation of Gsdmd mRNA in the skin tissue of AD patients. Moreover, we delved into the impact of GSDMD deletion and inhibition on AD-like skin lesions using a mouse model induced by the topical application of oxazolone (Oxa). We found that mice lacking GSDMD exhibited relieved AD signs and symptoms in terms of reduced skin thickness, scarring and scratching behavior compared to wild-type mice after induction of AD-like skin lesions. This was associated with decreased infiltration of inflammatory cells, reduced epidermal thickness, and decreased serum levels of IgE and IL-4. Western blot analysis further revealed decreased GSDMD cleavage in the skin of GSDMD knockout mice, and reduced expression of IL-1β and IL-18. Inhibition of GSDMD using the pharmacological agent disulfiram or the herbal compound matrine significantly attenuated the symptoms of AD-like skin lesions in wild-type mice, GSDMD cleavage and pro-inflammatory cytokines were reduced as well. Our results suggest that GSDMD-mediated pyroptosis plays a critical role in the development of AD-like skin lesions, and targeting GSDMD may be a promising therapeutic strategy for AD.

Targeting Skin Barrier Function in Atopic Dermatitis

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease in the general population. Skin barrier dysfunction is the central abnormality leading to AD. The cause of skin barrier dysfunction is complex and rooted in genetic mutations, interactions between the immune pathway activation and epithelial cells, altered host defense mechanisms, as well as environmental influences that cause epithelial cell activation and release of alarmins (such as thymic stromal lymphopoietin) that can activate the type 2 immune pathway, including generation of interleukins 4 and 13, which induces defects in the skin barrier and increased allergic inflammation. These inflammatory pathways are further influenced by environmental factors including the microbiome (especially Staphylococcus aureus), air pollution, stress, and other factors. As such, AD is a syndrome involving multiple phenotypes, all of which have in common skin barrier dysfunction as a key contributing factor. Understanding mechanisms leading to skin barrier dysfunction in AD is pointing to the development of new topical and systemic treatments in AD that helps keep skin borders secure and effectively treat the disease.

Observational study of pimecrolimus 1% cream for prevention of transcutaneous sensitization in children with atopic dermatitis during their first year of life

Introduction

Epidermal barrier dysfunction in children with atopic dermatitis can cause transcutaneous sensitization to allergens and allergic diseases. We evaluated the effectiveness of an early-intervention algorithm for atopic dermatitis treatment, utilizing pimecrolimus for long-term maintenance therapy, in reducing transcutaneous sensitization in infants.

Method

This was a single-center cohort observational study that enrolled children aged 1-4 months with family history of allergic diseases, moderate-to-severe atopic dermatitis, and sensitization to ≥ 1 of the investigated allergens. Patients who sought medical attention at atopic dermatitis onset (within 10 days) were group 1 "baseline therapy with topical glucocorticoids with subsequent transition to pimecrolimus as maintenance therapy"; patients who sought medical attention later were group 2 "baseline and maintenance therapy with topical glucocorticoids, without subsequent use of pimecrolimus". Sensitization class and level of allergen-specific immunoglobulin E were determined at baseline, and 6 and 12 months of age. Atopic dermatitis severity was evaluated using the Eczema Area and Severity Index score at baseline and 6, 9 and 12 months of age.

Results

Fifty-six and 52 patients were enrolled in groups 1 and 2, respectively. Compared with group 2, group 1 demonstrated a lower level of sensitization to cow's milk protein, egg white and house dust mite allergen at 6 and 12 months of age, and a more pronounced decrease in atopic dermatitis severity at 6, 9 and 12 months of age. No adverse events occurred.

Discussion

The pimecrolimus-containing algorithm was effective in treating atopic dermatitis and prophylaxis of early forms of allergic diseases in infants.

Trial registration

https://clinicaltrials.gov/ NCT04900948, retrospectively registered, 25 May 2021.

Isosorbide Fatty Acid Diesters Have Synergistic Anti-Inflammatory Effects in Cytokine-Induced Tissue Culture Models of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic disease in which epidermal barrier disruption triggers Th2-mediated eruption of eczematous lesions. Topical emollients are a cornerstone of chronic management. This study evaluated efficacy of two plant-derived oil derivatives, isosorbide di-(linoleate/oleate) (IDL) and isosorbide dicaprylate (IDC), using AD-like tissue culture models. Treatment of reconstituted human epidermis with cytokine cocktail (IL-4 + IL-13 + TNF-α + IL-31) compromised the epidermal barrier, but this was prevented by co-treatment with IDL and IDC. Cytokine stimulation also dysregulated expression of keratinocyte (KC) differentiation genes whereas treatment with IDC or IDL + IDC up-regulated genes associated with early (but not late) KC differentiation. Although neither IDL nor IDC inhibited Th2 cytokine responses, both compounds repressed TNF-α-induced genes and IDL + IDC led to synergistic down-regulation of inflammatory (IL1B, ITGA5) and neurogenic pruritus (TRPA1) mediators. Treatment of cytokine-stimulated skin explants with IDC decreased lactate dehydrogenase (LDH) secretion by more than 50% (more than observed with cyclosporine) and in vitro LDH activity was inhibited by IDL and IDC. These results demonstrate anti-inflammatory mechanisms of isosorbide fatty acid diesters in AD-like skin models. Our findings highlight the multifunctional potential of plant oil derivatives as topical ingredients and support studies of IDL and IDC as therapeutic candidates.

Type 2 Inflammation Contributes to Skin Barrier Dysfunction in Atopic Dermatitis

Skin barrier dysfunction, a defining feature of atopic dermatitis (AD), arises from multiple interacting systems. In AD, skin inflammation is caused by host-environment interactions involving keratinocytes as well as tissue-resident immune cells such as type 2 innate lymphoid cells, basophils, mast cells, and T helper type 2 cells, which produce type 2 cytokines, including IL-4, IL-5, IL-13, and IL-31. Type 2 inflammation broadly impacts the expression of genes relevant for barrier function, such as intracellular structural proteins, extracellular lipids, and junctional proteins, and enhances Staphylococcus aureus skin colonization. Systemic anti‒type 2 inflammation therapies may improve dysfunctional skin barrier in AD.

Atopic Dermatitis Biomarkers and the Movement Toward Personalized Treatment

Atopic dermatitis (AD) is a heterogeneous disorder with varying phenotypes. Although AD has long been associated with barrier dysfunction, the pathogenesis of this disease is more complex, involving many molecular markers in different functional domains. Biomarkers can be helpful in different ways, including predicting prognosis, measuring treatment response, and gauging disease severity. With the advent of targeted immunomodulators, biomarkers have the potential to take on new significance in terms of selecting appropriate therapies for patients. In this review, we have summarized the key findings related to biomarkers and AD, including the specific subtype differences. Clinicians will use this information to better understand the potential of biomarkers in AD and have a guide because more specific treatments are developed that are tailored toward individual molecular profiles.

Lithospermum erythrorhizon Alleviates Atopic Dermatitis-like Skin Lesions by Restoring Immune Balance and Skin Barrier Function in 2.4-Dinitrochlorobenzene-Induced NC/Nga Mice

The incidence of atopic dermatitis (AD), a disease characterized by an abnormal immune balance and skin barrier function, has increased rapidly in developed countries. This study investigated the anti-atopic effect of Lithospermum erythrorhizon (LE) using NC/Nga mice induced by 2,4-dinitrochlorobenzene. LE reduced AD clinical symptoms, including inflammatory cell infiltration, epidermal thickness, ear thickness, and scratching behavior, in the mice. Additionally, LE reduced serum IgE and histamine levels, and restored the T helper (Th) 1/Th2 immune balance through regulation of the IgG1/IgG2a ratio. LE also reduced the levels of AD-related cytokines and chemokines, including interleukin (IL)-1β, IL-4, IL-6, tumor necrosis factor-α (TNF-α), thymic stromal lymphopoietin, thymus and activation-regulated chemokine, macrophage-derived chemokine, regulated on activation, normal T cell expressed and secreted, and monocyte chemoattractant protein-1 in the serum. Moreover, LE modulated AD-related cytokines and chemokines expressed and secreted by Th1, Th2, Th17, and Th22 cells in the dorsal skin and splenocytes. Furthermore, LE restored skin barrier function by increasing pro-filaggrin gene expression and levels of skin barrier-related proteins filaggrin, involucrin, loricrin, occludin, and zonula occludens-1. These results suggest that LE is a potential therapeutic agent that can alleviate AD by modulating Th1/Th2 immune balance and restoring skin barrier function.

Topical therapy of atopic dermatitis with a focus on pimecrolimus

Atopic dermatitis (AD) is a chronic and relapsing, inflammatory skin disease characterized by impaired skin barrier function and immune system dysregulation that results in dryness, skin microbiome dysbiosis and intense pruritus. It is highly heterogeneous, and its management is demanding. Patients with AD are at greater risk of comorbidities such as attention-deficit hyperactivity disorder as well as other atopic diseases. Early-onset AD cases typically improve or resolve in late childhood; however, it is proposed that the prevalence of persistent or adult-onset AD is higher than previously thought. Basic therapy consists of emollient application and trigger avoidance, and when insufficient, topical corticosteroids (TCS) are the first-line treatment. However, corticophobia/steroid aversion and TCS side-effects, particularly on sensitive skin areas, lead to low compliance and insufficient disease control. Several long- and short-term randomized controlled and daily practice studies have demonstrated that topical calcineurin inhibitors, such as pimecrolimus, have similar anti-inflammatory effects to low-to-medium strength TCS, reduce pruritus and improve the quality of life of patients. In addition, pimecrolimus does not cause skin atrophy, is steroid-sparing and has a good safety profile, with no evidence for an increased risk of malignancies or skin infections. In general, pimecrolimus cream is well-accepted and well-tolerated, encouraging patient adherence and leading to its use by many physicians as a preferred therapy for children and sensitive skin areas.

Paediatric atopic eczema (atopic dermatitis) in South Africa: A practical algorithm for the management of mild-to-moderate disease in daily clinical practice

Background

Atopic eczema (AE) is a chronic, highly pruritic, inflammatory skin condition with increasing prevalence worldwide. Atopic eczema mostly affects children, impairing quality of life with poor disease control leading to progression of other atopic disorders. As most patients in South Africa have no access to specialist healthcare, a practical approach is needed for the management of mild-to-moderate AE in paediatric patients for daily clinical practice.

Methods

A panel of experts in AE convened to develop a practical algorithm for the management of AE for children and adolescents in South Africa.

Results

Regular moisturising with an oil-based emollient remains the mainstay of AE treatment. Severe AE flares should be managed with topical corticosteroids (TCSs). For mild-to-moderate AE flares in sensitive skin areas, a topical calcineurin inhibitor (TCI) should be applied twice daily from the first signs of AE until complete resolution. Topical corticosteroids may be used when TCIs are unavailable. In non-sensitive skin areas, TCSs should be used for mild-to-moderate AE, but TCIs twice daily may be considered. Proactive maintenance treatment with low-dose TCI or TCS 2–3 times weekly and the liberal use of emollients is recommended for patients with recurrent flares.

Conclusions

This algorithm aims to simplify treatment of paediatric AE, optimising clinical outcomes and reducing disease burden. This approach excludes treatment of patients with severe AE, who should be referred to specialist care. Emphasis has been given to the importance of general skincare, patient education and the topical anti-inflammatory medications available in South Africa (TCSs and TCIs).

Vehicles for atopic dermatitis therapies: more than just a placebo

A topical vehicle is a 'carrier system' for an active pharmaceutical (or cosmetic) substance, referred to hereafter as the drug, but a vehicle may also be used on its own as an emollient to ameliorate dry skin. It is well established that the vehicle plays an important role in determining the bioavailability of a given drug at its ultimate target within the skin. Yet in the treatment of atopic eczema/dermatitis (AD), wherein the structure and function of the skin's outer barrier play a pivotal role in the development and course of the condition, the interaction of the vehicle with this barrier carries a particular importance. It is now clear that the often-considered inert excipients of a vehicle bring about changes within the skin at the molecular level that promote barrier restoration and enhance innate immune defenses with therapeutic value to AD patients. Moreover, the vehicle control in randomized controlled trials (RCTs) increasingly displays significant efficacy. In light of this, we consider the implications of vehicle design in relation to AD pathophysiology and the role vehicles play as controls in RCTs of new drug treatments for this condition.

Leveraging Multilayered "Omics" Data for Atopic Dermatitis: A Road Map to Precision Medicine

Atopic dermatitis (AD) is a complex multifactorial inflammatory skin disease that affects ~280 million people worldwide. About 85% of AD cases begin in childhood, a significant portion of which can persist into adulthood. Moreover, a typical progression of children with AD to food allergy, asthma or allergic rhinitis has been reported (“allergic march” or “atopic march”). AD comprises highly heterogeneous sub-phenotypes/endotypes resulting from complex interplay between intrinsic and extrinsic factors, such as environmental stimuli, and genetic factors regulating cutaneous functions (impaired barrier function, epidermal lipid, and protease abnormalities), immune functions and the microbiome. Though the roles of high-throughput “omics” integrations in defining endotypes are recognized, current analyses are primarily based on individual omics data and using binary clinical outcomes. Although individual omics analysis, such as genome-wide association studies (GWAS), can effectively map variants correlated with AD, the majority of the heritability and the functional relevance of discovered variants are not explained or known by the identified variants. The limited success of singular approaches underscores the need for holistic and integrated approaches to investigate complex phenotypes using trans-omics data integration strategies. Integrating omics layers (e.g., genome, epigenome, transcriptome, proteome, metabolome, lipidome, exposome, microbiome), which often have complementary and synergistic effects, might provide the opportunity to capture the flow of information underlying AD disease manifestation. Overlapping genes/candidates derived from multiple omics types include FLG, SPINK5, S100A8, and SERPINB3 in AD pathogenesis. Overlapping pathways include macrophage, endothelial cell and fibroblast activation pathways, in addition to well-known Th1/Th2 and NFkB activation pathways. Interestingly, there was more multi-omics overlap at the pathway level than gene level. Further analysis of multi-omics overlap at the tissue level showed that among 30 tissue types from the GTEx database, skin and esophagus were significantly enriched, indicating the biological interconnection between AD and food allergy. The present work explores multi-omics integration and provides new biological insights to better define the biological basis of AD etiology and confirm previously reported AD genes/pathways. In this context, we also discuss opportunities and challenges introduced by “big omics data” and their integration.

A practical algorithm for topical treatment of atopic dermatitis in the Middle East emphasizing the importance of sensitive skin areas

Background There is a need for safe, effective treatment for atopic dermatitis (AD) in the Middle East. Objective To propose a practical algorithm for the treatment of AD throughout the Middle East. Methods An international panel of six experts from the Middle East and one from Europe developed the algorithm. The practical treatment guide was based on a review of published guidelines on AD, an evaluation of relevant literature published up to August 2016 and local treatment practices. Results Patients with an acute mild-to-moderate disease flare on sensitive body areas should apply the topical calcineurin inhibitor (TCI), pimecrolimus 1% cream twice daily until clearance. For other body locations, a TCI, either pimecrolimus 1% cream, tacrolimus 0.03% ointment in children or 0.1% ointment in adults, should be applied twice daily until clearance. Emollients should be used as needed. Patients experiencing acute severe disease flares should apply a topical corticosteroid (TCS) according to their label for a few days to reduce inflammation. After clinical improvement, pimecrolimus for sensitive skin areas or TCIs for other body locations should be used until there is a complete resolution of lesions. Conclusions These recommendations are expected to optimize AD management in patients across the Middle East.

Tacrolimus ointment for the treatment of adult and pediatric atopic dermatitis: Review on safety and benefits

Atopic dermatitis (AD) requires long-term management, mainly with topical anti-inflammatory agents. Topical corticosteroids (TCS) and tacrolimus ointment (TAC-O) are recommended as first-line treatments for AD. However, the long-term use of TCS is limited by cutaneous adverse events such as skin atrophy. For TAC-O, Japanese and US labelings were updated in 2003 and 2006, respectively, to include a boxed warning about a theoretical risk of skin cancer and lymphoma in patients treated with topical calcineurin inhibitors. However, TAC-O has been used worldwide for longer than 15 years to treat adult and pediatric patients with AD. Available data suggest that TAC-O is effective and well tolerated, and can improve quality of life. TAC-O has successfully been used in the proactive management of AD consisting of long-term intermittent use to prevent, delay or reduce the occurrence of AD flares. Systemic drug absorption after TAC-O application is negligible and unlikely to result in systemic immunosuppression. There is currently no strong evidence of an increased rate of malignancy in treated patients, and observational data from postmarketing surveillance studies have shown no safety concerns. In the absence of robust evidence, the warning about the carcinogenic potential in the Japanese labeling for TAC-O does not appear justified and should be reconsidered. This mitigation of description would allow adult and pediatric patients with AD to receive the effective treatment more appropriately.

Atopic dermatitis

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease, with a lifetime prevalence of up to 20% and substantial effects on quality of life. AD is characterized by intense itch, recurrent eczematous lesions and a fluctuating course. AD has a strong heritability component and is closely related to and commonly co-occurs with other atopic diseases (such as asthma and allergic rhinitis). Several pathophysiological mechanisms contribute to AD aetiology and clinical manifestations. Impairment of epidermal barrier function, for example, owing to deficiency in the structural protein filaggrin, can promote inflammation and T cell infiltration. The immune response in AD is skewed towards T helper 2 cell-mediated pathways and can in turn favour epidermal barrier disruption. Other contributing factors to AD onset include dysbiosis of the skin microbiota (in particular overgrowth of Staphylococcus aureus), systemic immune responses (including immunoglobulin E (IgE)-mediated sensitization) and neuroinflammation, which is involved in itch. Current treatments for AD include topical moisturizers and anti-inflammatory agents (such as corticosteroids, calcineurin inhibitors and cAMP-specific 3',5'-cyclic phosphodiesterase 4 (PDE4) inhibitors), phototherapy and systemic immunosuppressants. Translational research has fostered the development of targeted small molecules and biologic therapies, especially for moderate-to-severe disease.

Targeting PRPK and TOPK for skin cancer prevention and therapy

Solar ultraviolet (sUV) irradiation is a major environmental carcinogen that can cause inflammation and skin cancer. The costs and morbidity associated with skin cancer are increasing, and therefore identifying molecules that can help prevent skin carcinogenesis is important. In this study, we identified the p53-related protein kinase (PRPK) as a novel oncogenic protein that is phosphorylated by the T-LAK cell-originated protein kinase (TOPK). Knockdown of TOPK inhibited PRPK phosphorylation and conferred resistance to solar-simulated light (SSL)-induced skin carcinogenesis in mouse models. In the clinic, acute SSL irradiation significantly increased epidermal thickness as well as total protein and phosphorylation levels of TOPK and PRPK in human skin tissues. We identified two PRPK inhibitors, FDA-approved rocuronium bromide (Zemuron^®) or betamethasone 17-valerate (Betaderm^®) that could attenuate TOPK-dependent PRPK signaling. Importantly, topical application of either rocuronium bromide or betamethasone decreased SSL-induced epidermal hyperplasia, neovascularization, and cutaneous squamous cell carcinoma (cSCC) development in SKH1 (Crl: SKH1-Hr^hr) hairless mice by inhibiting PRPK activation, and also reduced expression of the proliferation and oncogenesis markers, COX-2, cyclin D1, and MMP-9. This study is the first to demonstrate that targeting PRPK could be useful against sUV-induced cSCC development.

Upregulation of FLG, LOR, and IVL Expression by Rhodiola crenulata Root Extract via Aryl Hydrocarbon Receptor: Differential Involvement of OVOL1

Rhodiola species are antioxidative, salubrious plants that are known to inhibit oxidative stress induced by ultraviolet and γ-radiation in epidermal keratinocytes. As certain phytochemicals activate aryl hydrocarbon receptors (AHR) or OVO-like 1 (OVOL1) to upregulate the expression of epidermal barrier proteins such as filaggrin (FLG), loricrin (LOR), and involucrin (IVL), we investigated such regulation by Rhodiola crenulata root extract (RCE). We demonstrated that RCE induced FLG and LOR upregulation in an AHR-OVOL1-dependent fashion. However, RCE-mediated IVL upregulation was AHR-dependent but OVOL1-independent. Coordinated upregulation of skin barrier proteins by RCE via AHR may be beneficial in the management of barrier-disrupted inflammatory skin diseases such as atopic dermatitis.

Paeonol suppresses solar ultraviolet-induced skin inflammation by targeting T-LAK cell-originated protein kinase

Excessive exposure to solar UV (SUV) is related with numerous human skin disorders, such as skin inflammation, photoaging and carcinogenesis. T-LAK cell- originated protein kinase (TOPK), an upstream of p38 mitogen-activated protein kinase (p38) and c-Jun N-terminal kinases (JNKs), plays an important role in SUV -induced skin inflammation, and targeting TOPK has already been a strategy to prevent skin inflammation. In this study, we found that the expression of TOPK, phosphorylation of p38 or JNKs was increased in human solar dermatitis tissues. The level of phosphorylation of p38 or JNKs increased in a dose and time dependent manner in HaCat cells or JB6 Cl41 cells after SUV treatment. Paeonol is an active component isolated from traditional Chinese herbal medicines, and MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2H-tetrazdium) assay showed that it has no toxicity to cells. Microscale thermophoresis (MST) assay showed that paeonol can bind TOPK ex vivo. In vitro kinase assay showed paeonol can inhibit TOPK activity. Ex vivo studies further showed paeonol suppressed SUV-induced phosphorylation level of p38, JNKs, MSK1 and histone H2AX by inhibiting TOPK activity in a time and dose dependent manner. Paeonol inhibited the secretion of IL-6 and TNF-α in HaCat and JB6 cells ex vivo. In vivo studies demonstrated that paeonol inhibited SUV-induced increase of TOPK, the phosphorylation of p38, JNKs and H2AX, and the secretion of IL-6 and TNF-α in Babl/c mouse. In summary, our data indicated a protective role of paeonol against SUV-induced inflammation by targeting TOPK, and paeonol could be a promising agent for the treatment of SUV-induced skin inflammation.

Pinus densiflora bark extract ameliorates 2,4-dinitrochlorobenzene-induced atopic dermatitis in NC/Nga mice by regulating Th1/Th2 balance and skin barrier function

Korean red pine (Pinus densiflora) bark has been traditionally used in Korea and other parts of East Asia to relieve inflammatory diseases. Although many studies using P. densiflora bark have been reported, its effect on atopic dermatitis (AD) has not been elucidated. Thus, we investigated whether the P. densiflora bark extract (PBE) has potential to attenuate AD symptoms and elucidated the molecular mechanism. Oral administration of PBE to mice with 2,4-dinitrochlorobenzene (DNCB)-induced AD lessened dermatitis scores and scratching behavior and significantly reduced measures of epidermal thickness, infiltration of mast cells and eosinophils, levels of immunoglobulin E (IgE), and IgG₁ /IgG_2a ratio in serum. PBE not only inhibited IL-4, IL-5, and IL-13 but also increased IFN-γ in splenic production. Furthermore, PBE significantly suppressed mRNA expression of thymic stromal lymphopoietin and further downregulated the mRNA expression of Th2 and Th17 cytokines such as IL-4, IL-13, IL-17, IL-31, and TNF-α. In addition, the protein expressions of filaggrin, involucrin, and loricrin in lesional skin were recovered by PBE. These results suggest that PBE attenuates DNCB-induced AD via regulating Th1/Th2 balance and skin barrier function.

Elucidating mechanistic insights into drug action for atopic dermatitis: a systems biology approach

BACKGROUND

Topical Betamethasone (BM) and Pimecrolimus (PC) are widely used drugs in the treatment of atopic dermatitis (AD). Though the biomolecules and biological pathways affected by the drugs are known, the causal inter-relationships among these pathways in the context of skin is not available. We aim to derive this insight by using transcriptomic data of AD skin samples treated with BM and PC using systems biology approach.

METHODS

Transcriptomic datasets of 10 AD patients treated with Betamethasone and Pimecrolimus were obtained from GEO datasets. We used a novel computational platform, eSkIN ( www.persistent.com/eskin ), to perform pathway enrichment analysis for the given datasets. eSkIN consists of 35 skin specific pathways, thus allowing skin-centric analysis of transcriptomic data. Fisher's exact test was used to compute the significance of the pathway enrichment. The enriched pathways were further analyzed to gain mechanistic insights into the action of these drugs.

RESULTS

Our analysis highlighted the molecular details of the mechanism of action of the drugs and corroborated the known facts about these drugs i.e. BM is more effective in triggering anti-inflammatory response but also causes more adverse effect on skin barrier than PC. In particular, eSkIN helped enunciate the biological pathways activated by these drugs to trigger anti-inflammatory response and its effect on skin barrier. BM suppresses pathways like TNF and TLRs, thus inhibiting NF-κB while PC targets inflammatory genes like IL13 and IL6 via known calcineurin-NFAT pathway. Furthermore, we show that the reduced skin barrier function by BM is due to the suppression of activators like AP1 transcription factors, CEBPs.

CONCLUSION

We thus demonstrate the detailed mechanistic insight into drug action of AD using a novel computational approach.

Prostaglandin E2 stimulates adaptive IL-22 production and promotes allergic contact dermatitis

BACKGROUND

Atopic dermatitis (AD) and allergic contact dermatitis (ACD) are both forms of eczema and are common inflammatory skin diseases with a central role of T cell-derived IL-22 in their pathogenesis. Although prostaglandin (PG) E2 is known to promote inflammation, little is known about its role in processes related to AD and ACD development, including IL-22 upregulation.

OBJECTIVES

We sought to investigate whether PGE2 has a role in IL-22 induction and development of ACD, which has increased prevalence in patients with AD.

METHODS

T-cell cultures and in vivo sensitization of mice with haptens were used to assess the role of PGE2 in IL-22 production. The involvement of PGE2 receptors and their downstream signals was also examined. The effects of PGE2 were evaluated by using the oxazolone-induced ACD mouse model. The relationship of PGE2 and IL-22 signaling pathways in skin inflammation were also investigated by using genomic profiling in human lesional AD skin.

RESULTS

PGE2 induces IL-22 from T cells through its receptors, E prostanoid receptor (EP) 2 and EP4, and involves cyclic AMP signaling. Selective deletion of EP4 in T cells prevents hapten-induced IL-22 production in vivo, and limits atopic-like skin inflammation in the oxazolone-induced ACD model. Moreover, both PGE2 and IL-22 pathway genes were coordinately upregulated in human AD lesional skin but were at less than significant detection levels after corticosteroid or UVB treatments.

CONCLUSIONS

Our results define a crucial role for PGE2 in promoting ACD by facilitating IL-22 production from T cells.

An Integrated Model of Atopic Dermatitis Biomarkers Highlights the Systemic Nature of the Disease

Current atopic dermatitis (AD) models link epidermal abnormalities in lesional skin to cytokine activation. However, there is evolving evidence of systemic immune activation and detectable abnormalities in nonlesional skin. Because some of the best single correlations with severity (Scoring of AD, or SCORAD) are detected not only in lesional but also nonlesional skin and blood, more complex biomarker models of AD are needed. We thus performed extensive biomarker measures in these compartments using univariate and multivariate approaches to correlate disease biomarkers with SCORAD and with a combined hyperplasia score [thickness and keratin 16 (K16) mRNA] at baseline and after cyclosporine A treatment in 25 moderate to severe AD patients. Increases in serum cytokines and chemokines (IL-13, IL-22, CCL17) were found in AD versus healthy individuals and were reduced with treatment. SCORAD correlated with immune (IL-13, IL-22) and epidermal (thickness, K16) measures in lesional and, even more strongly, in nonlesional AD. Serum cytokines also had higher correlations with nonlesional markers at baseline and with treatment. Multivariate U statistics improved baseline and treatment-response SCORAD correlations. Nonlesional models showed the strongest correlations, with further improvement upon integration of serum markers. Even better correlations were obtained between biomarkers and the hyperplasia score. Larger cohorts are needed to confirm these preliminary data.

Treatment of Eczema: Corticosteroids and Beyond

Atopic dermatitis (AD) is a chronic inflammatory skin condition that requires a manifold approach to therapy. The goal of therapy is to restore the function of the epidermal barrier and to reduce skin inflammation. This can be achieved with skin moisturization and topical anti-inflammatory agents, such as topical corticosteroids and calcineurin inhibitors. Furthermore, proactive therapy with twice weekly use of both topical corticosteroids and calcineurin inhibitors in previously affected areas has been found to reduce the time to the next eczematous flare. Adjunctive treatment options include wet wrap therapy, anti-histamines, and vitamin D supplementation. Bacterial colonization, in particular Staphylococcus aureus, can contribute to eczematous flares and overt infection. Use of systemic antibiotics in infected lesions is warranted; however, empiric antibiotics use in uninfected lesions is controversial. Local antiseptic measures (i.e., bleach baths) and topical antimicrobial therapies can be considered in patients with high bacterial colonization. Difficult-to-treat AD is a complex clinical problem that may require re-evaluation of the initial diagnosis of AD, especially if the onset of disease occurs in adulthood. It may also necessitate evaluation for contact, food, and inhaled allergens that may exacerbate the underlying AD. There are a host of systemic therapies that have been successful in patients with difficult-to-treat AD, however, these agents are limited by their side effect profiles. Lastly, with further insight into the pathophysiology of AD, new biological agents have been investigated with promising results.

Topical treatment of atopic dermatitis in children: current challenges and answers

Atopic dermatitis (AD) is the most prevalent skin disease in the early childhood and is a considerable problem both for patients and members of their families and for the society on the whole. In most cases, AD requires a long-term therapy such as the use of anti-inflammatory drugs. Selective inhibitors of the synthesis and release of proinflammatory cytokines - topical calcineurin inhibitors (Tcis) - are now used to solve this problem, with pimecrolimus being one of them. Pimecrolimus has been thoroughly examined for the past decade in different clinical studies involving a total of over 4,000 infants (below 2 years of age). These studies demonstrated the efficacy and safety of pimecrolimus for AD in children provided it is used in a long-term therapy on an intermittent basis. Unlike topical corticosteroids, the long-term use of pimecrolimus is not associated with any risk of development of systemic immunosuppression, skin atrophy, skin barrier dysfunction or systemic absorption so it is safe even if applied to the most sensitive skin areas. In view of this, the authors make a conclusion that pimecrolimus used in the form of a cream is a safe and efficient drug for the treatment of infants aged over three months suffering from atopic dermatitis.

The tryptophan metabolism enzyme L-kynureninase is a novel inflammatory factor in psoriasis and other inflammatory diseases

BACKGROUND

Many human diseases arise from or have pathogenic contributions from a dysregulated immune response. One pathway with immunomodulatory ability is the tryptophan metabolism pathway, which promotes immune suppression through the enzyme indoleamine 2,3-dioxygenase (IDO) and subsequent production of kynurenine. However, in patients with chronic inflammatory skin disease, such as psoriasis and atopic dermatitis (AD), another tryptophan metabolism enzyme downstream of IDO, L-kynureninase (KYNU), is heavily upregulated. The role of KYNU has not been explored in patients with these skin diseases or in general human immunology.

OBJECTIVE

We sought to explore the expression and potential immunologic function of the tryptophan metabolism enzyme KYNU in inflammatory skin disease and its potential contribution to general human immunology.

METHODS

Psoriatic skin biopsy specimens, as well as normal human skin, blood, and primary cells, were used to investigate the immunologic role of KYNU and tryptophan metabolites.

RESULTS

Here we show that KYNU(+) cells, predominantly of myeloid origin, infiltrate psoriatic lesional skin. KYNU expression positively correlates with disease severity and inflammation and is reduced on successful treatment of psoriasis or AD. Tryptophan metabolites downstream of KYNU upregulate several cytokines, chemokines, and cell adhesions. By mining data on several human diseases, we found that in patients with cancer, IDO is preferentially upregulated compared with KYNU, whereas in patients with inflammatory diseases, such as AD, KYNU is preferentially upregulated compared with IDO.

CONCLUSION

Our results suggest that tryptophan metabolism might dichotomously modulate immune responses, with KYNU as a switch between immunosuppressive versus inflammatory outcomes. Although tryptophan metabolism is increased in many human diseases, how tryptophan metabolism is proceeding might qualitatively affect the immune response in patients with that disease.

Efficacy of topical azathioprine and betamethasone versus betamethasone-only emollient cream in 2-18 years old patients with moderate-to-severe atopic dermatitis: A randomized controlled trial

Background:

Atopic dermatitis is a chronic skin disease with increasing prevalence worldwide and a considerable burden especially among children. To circumvent the problems related to oral azathioprine (AZT) we aimed to evaluate its topical variant and assess its efficacy in patients aged 2–18.

Materials and Methods:

In a single-blind trial, we randomized the patients into two groups, one treated with topical emollient containing AZT and betamethasone (BM), and the other treated solely with topical emollient of BM. The treatments were administered twice a day for 8 weeks in both groups. The efficacy, recurrence, and the presence of side effects were evaluated using SPSS 20.

Results:

The amount of reduction in severity scoring for atopic dermatitis (SCORAD) score was significantly greater in the group treated with the topical AZT (P = 0.024). Incidentally, there were no difference between two treatments in difference in proportions of recurrence and adverse effects as well as SCORAD reduction in subgroups of sex and age (all P > 0.05).

Conclusions:

Our results showed the superiority of topical AZT over BM with a low recurrence and adverse effects. No expectation of severe side effects, like those of oral AZT, is the major advantage of topical AZT. The sample size was an issue in uncovering the value of AZT in the subgroups. Conducting prolonged studies of quality-of-life and comparing the topical AZT potency relative to the common alternatives are recommended areas of future work.

Pimecrolimus in atopic dermatitis: consensus on safety and the need to allow use in infants

Atopic dermatitis (AD) is a distressing dermatological disease, which is highly prevalent during infancy, can persist into later life and requires long-term management with anti-inflammatory compounds. The introduction of the topical calcineurin inhibitors (TCIs), tacrolimus and pimecrolimus, more than 10 yr ago was a major breakthrough for the topical anti-inflammatory treatment of AD. Pimecrolimus 1% is approved for second-line use in children (≥2 yr old) and adults with mild-to-moderate AD. The age restriction was emphasized in a boxed warning added by the FDA in January 2006, which also highlights the lack of long-term safety data and the theoretical risk of skin malignancy and lymphoma. Since then, pimecrolimus has been extensively investigated in short- and long-term studies including over 4000 infants (<2 yr old). These studies showed that pimecrolimus effectively treats AD in infants, with sustained improvement with long-term intermittent use. Unlike topical corticosteroids, long-term TCI use does not carry the risks of skin atrophy, impaired epidermal barrier function or enhanced percutaneous absorption, and so is suitable for AD treatment especially in sensitive skin areas. Most importantly, the studies of pimecrolimus in infants provided no evidence for systemic immunosuppression, and a comprehensive body of evidence from clinical studies, post-marketing surveillance and epidemiological investigations does not support potential safety concerns. In conclusion, the authors consider that the labelling restrictions regarding the use of pimecrolimus in infants are no longer justified and recommend that the validity of the boxed warning for TCIs should be reconsidered.

The effect of tacrolimus compared with betamethasone valerate on the skin barrier in volunteers with quiescent atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is an inflammatory skin disease arising as a result of immune system and skin barrier defects. Topical corticosteroids are safe and effective treatments for AD, when used in short courses. Prolonged use is associated with skin barrier damage. Topical calcineurin inhibitors are alternative immune-modulating treatments for AD purported to have no negative effects on the skin barrier.

OBJECTIVES

To compare the effects of betamethasone valerate 0·1% cream (BMVc) and tacrolimus 0·1% ointment (TACo) on the skin barrier.

METHODS

Twenty volunteers with quiescent AD (no active signs for 6 months) participated in a randomized observer-blind study, wherein BMVc was applied to one forearm and TACo to the other, twice daily for 4 weeks. The biophysical/biological properties of the stratum corneum were assessed before and after treatment. Nine volunteers with active disease and 10 with healthy skin were assessed at untreated sites.

RESULTS

BMVc significantly reduced skin barrier function, integrity and cohesion, and the levels of pyrrolidone carboxylic acid (PCA) and urocanic acid (UCA) towards the subclinical barrier defect observed in patients with AD (nonlesional sites). TACo preserved skin barrier function, integrity, cohesion and PCA and UCA levels, while significantly increasing skin hydration to levels comparable with healthy skin. Both treatments reduced skin surface pH and trypsin-like protease activity, with TACo doing so to a significantly greater degree.

CONCLUSION

In quiescent AD, 4 weeks of BMVc treatment adversely affected the biophysical properties of the skin and reduced the levels of natural moisturizing factor, whereas TACo improved the condition of the skin barrier.

Advances in the diagnosis and therapeutic management of atopic dermatitis

Atopic dermatitis is a very prevalent disease that affects children as well as adults. The disease has a severe impact on quality of life for the patients and their families. The skin in atopic dermatitis patients is a site of both a severe inflammatory reaction dominated by lymphocytes and decreased skin barrier function. The treatment of the disease is mainly aimed at reducing the inflammation in the skin and/or restoring the skin barrier function. However, most of the treatments used today singularly aim at reducing the inflammation in the skin. Depending on the severity of the disease, the anti-inflammatory treatment may be topical or systemic, but basic treatment, no matter the severity, should always be emollients. In addition, new studies have shown good effects of psychosocial interventions, such as eczema schools, for patients and their families. This review covers the latest trends in the treatment of atopic dermatitis.

Immune Pathways in Atopic Dermatitis, and Definition of Biomarkers through Broad and Targeted Therapeutics

Atopic dermatitis (AD) is the most common inflammatory skin disease. Recent research findings have provided an insight into the complex pathogenic mechanisms involved in this disease. Despite a rising prevalence, effective and safe therapeutics for patients with moderate-to-severe AD are still lacking. Biomarkers of lesional, nonlesional skin, and blood have been developed for baseline as well as after treatment with broad and specific treatments (i.e., cyclosporine A and dupilumab). These biomarkers will help with the development of novel targeted therapeutics and assessment of disease reversal, with the promise of a more personalized treatment approach. Since AD involves more than one subtype (i.e., intrinsic/extrinsic, pediatric/adult, etc.), these molecular fingerprints needs to be validated in all subpopulations with AD.

The translational revolution and use of biologics in patients with inflammatory skin diseases

Psoriasis and atopic dermatitis (AD) are common inflammatory skin diseases characterized by immune-mediated inflammation and abnormal keratinocyte differentiation. Although T-cell infiltration characterizes both diseases, T-cell polarization differs. Psoriasis is currently the best model for translational medicine because many targeted therapeutics have been developed and testing of targeted therapeutics has cemented psoriasis as IL-23/TH17 polarized. In patients with AD, although therapeutic development is approximately a decade behind that in patients with psoriasis, there is now active development and testing of targeted therapeutics against various immune axes (TH2, TH22, and IL-23/TH17). These clinical trials and subsequent molecular analyses using human samples will be able to clarify the relative roles of polar cytokines in patients with AD.

Immunological and molecular targets of atopic dermatitis treatment

Atopic dermatitis (AD) is a common, chronic inflammatory skin disease with a highly variable clinical phenotype and heterogeneous pathophysiology. Its pathogenesis is associated with alterations to both the skin barrier and the immune system, which may in turn be influenced by genetic mutations and the patient's environment. Basic and translational research, as well as clinical trials, have helped broaden our knowledge of the molecular mechanisms underlying the development of AD and to identify potential treatment targets and approaches. These include new ways of reducing transepidermal water loss and the shedding of corneocytes, new ways of interacting with established molecular targets (such as histamine receptors and interleukins and other T-cell cytokines), and the identification of new molecular targets (such as toll-like receptors and tight junction proteins). Well-established treatment options such as emollients, corticosteroids and topical calcineurin inhibitors will clearly continue to have a role in treating AD. Among the new agents that could be joining them in the near future are sphinganin (a precursor of ceramides 1 and 3), cannabinoids, highly targeted monoclonal antibodies and subcutaneous immunotherapy.

Atopic dermatitis and skin allergies - update and outlook

During the last few years, an impressive amount of experimental studies and clinical trials have dealt with a variety of distinct topics in allergic skin diseases - especially atopic dermatitis. In this update, we discuss selected recent data that provide relevant insights into clinical and pathophysiological aspects of allergic skin diseases or discuss promising targets and strategies for the future treatment of skin allergy. This includes aspects of barrier malfunction and inflammation as well as the interaction of the cutaneous immune system with the skin microbiome and diagnostic procedures for working up atopic dermatitis patients. Additionally, contact dermatitis, urticaria, and drug reactions are addressed in this review. This update summarizes novel evidence, highlighting current areas of uncertainties and debates that will stimulate scientific discussions and research activities in the field of atopic dermatitis and skin allergies in the future.

Evaluation of the antipruritic effects of topical pimecrolimus in non-atopic prurigo nodularis: results of a randomized, hydrocortisone-controlled, double-blind phase II trial

BACKGROUND

In the treatment of atopic dermatitis, pimecrolimus has high antipruritic effects.

OBJECTIVE

To investigate the efficacy of 1% pimecrolimus cream in comparison to 1% hydrocortisone cream in non-atopic prurigo nodularis (PN).

METHODS

A randomized, controlled, double-blind study with intraindividual randomization was done in 30 patients (17 females, 13 males; mean age 58.5 years) with PN.

RESULTS

Pruritus intensity decreased significantly (p < 0.001) on both treated sides as early as after 10 days of treatment; scratch lesions improved (p < 0.001). Quality of life as assessed by the Dermatology Life Quality Index improved significantly. However, a significant advantage of pimecrolimus over hydrocortisone was not found.

CONCLUSION

The results suggest that the non-steroid pimecrolimus is an effective alternative for PN treatment.

Atopic dermatitis 2.0: from the clinical phenotype to the molecular taxonomy and stratified medicine

Atopic dermatitis (AD) is a paradigmatic inflammatory chronic skin disease. As for other chronic skin diseases, (i) the spectrum of the clinical phenotype and severity as well as (ii) the genetic background and (iii) the underlying mechanisms strongly suggest a high degree of pathophysiological heterogeneity yet leading to a similar clinical pattern, that is, the eczematous skin lesion, but showing distinct progression patterns. This review suggests to exploit the recent knowledge about AD for a novel approach proposing a tentative first molecular taxonomy of this disease based on the genotype and endophenotype. The consequences in terms of personalized prevention and management are delineated.

Update in clinical allergy and immunology

In the recent years, a tremendous body of studies has addressed a broad variety of distinct topics in clinical allergy and immunology. In this update, we discuss selected recent data that provide clinically and pathogenetically relevant insights or identify potential novel targets and strategies for therapy. The role of the microbiome in shaping allergic immune responses and molecular, as well as cellular mechanisms of disease, is discussed separately and in the context of atopic dermatitis, as an allergic model disease. Besides summarizing novel evidence, this update highlights current areas of uncertainties and debates that, as we hope, shall stimulate scientific discussions and research activities in the field.

Evaluation of methods for the isolation of high quality RNA from bovine and cervine hide biopsies

Molecular investigations of the ruminant response to ectoparasites at the parasite-host interface are critically dependent upon the quality of RNA. The complexity of ruminant skin decreases the capacity to obtain high quality RNA from biopsy samples, which directly affects the reliability of data produced by gene expression experiments. Two methods for isolating total RNA from skin were compared and the use of 4M guanidinium isothiocyanate (GITC) during frozen storage of the specimens was evaluated. In addition, the best procedure for RNA isolation from bovine skin punch biopsies was also tested on white-tailed deer skin biopsies. Skin biopsy punches were collected and frozen prior to pulverization for RNA isolation. Total RNA quantity and integrity were determined by spectrophotometry and capillary electrophoresis technology, respectively. Significantly increased total RNA yield (P < 0.05) and higher integrity (P < 0.05) were obtained with a TRI Reagent® isolation method. Freezing and subsequent storage of bovine skin punch biopsies in 4 M GITC did not affect the amount or integrity of total RNA recovered by either RNA isolation method. However, quantity and integrity of total RNA extracted with the TRI Reagent method were again significantly higher than with the alternate technique, confirming it as the superior method. The TRI Reagent isolation method also yielded high quality total RNA from white-tailed deer skin punch biopsies, suggesting the usefulness of this method for obtaining RNA of a quality suitable for gene expression studies in other ruminant species.