Inhibitory effect of 5,6-dihydroergosteol-glucoside on atopic dermatitis-like skin lesions via suppression of NF-κB and STAT activation

Therapeutic effect of bosentan on 2, 4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis mouse model

Eczematous or atopic dermatitis (AD) is a chronic autoinflammatory skin disorder distinguished by severe itching, scratching, and erosion. Bosentan is an endothelin receptor antagonist with improved immunomodulatory and anti-inflammatory actions. This study aimed to assess the efficiency of topical bosentan in alleviating a 2, 4-dinitrochlorobenzene (DNCB)-induced mouse model of AD. 50 Swiss albino mice were haphazardly grouped into 5 teams of 10 each. The first week of the experiment involved DNCB sensitization on back skin mice, preceding a four-week DNCB challenge to induce AD-like skin inflammation. The control group gets no treatment. The induction group administered DNCB only. Starting two hours after the second sensitization, the vehicle group received topical vehicle solution, the bosentan group received 5% bosentan ointment, and the tacrolimus group received 0.1% tacrolimus ointment once daily for a period of four weeks. Topical bosentan markedly mitigated DNCB-aggravated AD-like skin lesions, as displayed by decreased total dermatitis scores and lowering the upregulated counts of total leukocytes, neutrophils, lymphocytes, monocytes, and eosinophils. Additionally, bosentan dramatically alleviated interleukin (IL)-4 and IL-13 immunohistochemistry scores, as well as IL-1β, IL-6, IL-17, TNFα, and IFN-γ epidermal levels. In conclusion, Bosentan treatment also significantly diminished levels of immunoglobulin E (IgE) and oxidative biomarker malondialdehyde (MDA) and histopathology scores, notably epidermal thickness and inflammation. Bosentan mitigates the severity of DNCB-induced AD-like skin inflammation, possibly owing to its potent anti-inflammatory and immunomodulatory properties.

Synthesis of novel α-spinasterol derivatives and their inhibitory effects on CCL17 and CCL22 chemokine expression

Natural α-spinasterol is well known for its various biological activities. In this study, we investigated the anti-inflammatory effects of newly synthesized α-spinasterol derivatives by tracking the expression of CCL17 and CCL22 chemokines, which serve as biomarkers for immune cell trafficking in skin inflammation. Initially, the 3-epimer of α-spinasterol, which results from inversion of stereochemistry at the C-3 position of α-spinasterol, was synthesized using the Mitsunobu reaction. Subsequently, new compounds were synthesized by introducing azido, amino, and amide groups at the C-3 position of α-spinasterol or 3-epi-α-spinasterol. The anti-inflammatory activity of these compounds was evaluated by examining their inhibitory effects on the mRNA expression of CCL17 and CCL22. Among these derivatives, 3α-8, 3α-12b, and 3α-12c exhibited potential anti-inflammatory activity in vitro, compared to α-spinasterol. Furthermore, compound 3α-8 showed even greater activity than 3α-12b and 3α-12c, underscoring its potential as a highly effective agent. These results suggest that the newly synthesized α-spinasterol derivatives hold promise as candidates for skin inflammation therapeutics.

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

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

Therapeutic effects of chamomile volatile oil nanoemulsion/Bletilla striata polysaccharides gels on atopic dermatitis

Atopic dermatitis (AD) is a prevalent chronic skin condition characterized by complex immune responses. Chamomile possesses potent anti-inflammatory properties and has been widely used in treating various skin diseases. This study aimed to assess the therapeutic benefits of chamomile volatile oil nanoemulsion gels (CVO-NEGs) for the treatment of AD. Chamomile volatile oil nanoemulsions (CVO-NEs) were prepared using the phase transition method, yielding spherical nanoparticles with a particle size of 19.07 nm. Subsequently, Bletilla striata polysaccharides were employed to encapsulate CVO-NEs, resulting in the formation of CVO-NEGs. In vivo studies demonstrated that the preparation of CVO-NEGs enhanced the biological activity of volatile oil in AD therapy. Histopathological results indicated that CVO-NEGs reduced skin damage, epidermal thickness, and mast cell infiltration. CVO-NEGs suppressed IgG production and reduced the levels of cytokines, including TNF-α, IL-4, and IFN-γ, in AD mice. Furthermore, flow cytometry revealed that CVO-NEGs were involved in regulating the differentiation of CD4+ T cell subsets. The immune imbalance of Th1/Th2 in AD mice can be controlled, resulting in a reduction in the hypersensitivity reaction caused by excessive Th2 activation. In conclusion, the present study confirms that CVO-NEGs have the potential to serve as an effective alternative treatment for AD.

Diterpenoid DGT alleviates atopic dermatitis-like responses in vitro and in vivo via targeting IL-4Rα

BACKGROUND

Atopic dermatitis is a common chronic inflammatory skin disease characterized by relapsing eczema and intense itch. DGT is a novel synthetic heterocyclic diterpenoid derived from plants. Its therapeutic potential and mechanism(s) of action are poorly understood.

OBJECTIVES

We investigated the potent therapeutic effect of DGT on atopic dermatitis, exploring the underlying mechanisms and determining whether DGT is a safe and well-tolerated topical treatment.

METHODS

We observed anti-inflammatory effects of DGT on tumor necrosis factor-α/interferon-γ-treated human keratinocytes, and anti-allergic effects on immunoglobulin E-sensitized bone marrow-derived mast cells. In vivo, DGT was topically applied to two experimental mouse models of atopic dermatitis: oxazolone-induced sensitization and topically applied calcipotriol. Then the therapeutic effects of DGT were evaluated physiologically and morphologically. Moreover, we performed nonclinical toxicology and safety pharmacology research, including general toxicity, pharmacokinetics, and safety pharmacology on the cardiovascular, respiratory, and central nervous systems.

RESULTS

In keratinocytes, DGT reduced the expression of inflammatory factors, promoting the expression of barrier functional proteins and tight junctions and maintaining the steady state of barrier function. DGT also inhibited the activation and degranulation of mast cells induced by immunoglobulin E. Moreover, we found that interleukin-4 receptor-α was the possible target of DGT. Meanwhile, DGT had therapeutic effects on oxazolone/calcipotriol-treated mice. Notably, our pharmacology results demonstrated that DGT was safe and nontoxic in our studies.

CONCLUSION

DGT's potent anti-inflammatory effects and good safety profile suggest that it is a potential candidate for the treatment of atopic dermatitis.

Oral and topical administration of a geranyl acetophenone attenuates DNCB-induced atopic dermatitis-like skin lesions in BALB/c mice

Atopic dermatitis (AD) is a chronic, allergic inflammatory skin disorder that lacks a definite cure. Using a mouse DNCB-induced AD-like skin lesions model, this study evaluated the potential therapeutic utility of tHGA as an oral and topical treatment for AD. Male BALB/c mice were sensitised and challenged with 1% and 0.5% DNCB on their shaved dorsal skin. Mice in the treatment group were administered tHGA (20, 40, and 80 mg/kg) orally three times per week for 2 weeks, or tHGA (0.2%, 1%, and 5%) topically once daily for 12 days. On day 34, the mice were euthanized, and blood and dorsal skin samples were obtained for analysis. All doses of orally and topically administered tHGA significantly improved scratching, epidermal thickness, blood eosinophilia and mast cell infiltration. There was a minor discrepancy between the two routes of administration, with orally treated tHGA showing significant reductions in Scoring of Atopic Dermatitis (SCORAD), tissue eosinophil infiltration, serum IgE and skin IL-4 levels with treatment of 40 and 80 mg/kg tHGA, whereas topically applied tHGA showed significant reductions in all dosages. These findings suggest that tHGA exhibited therapeutic potential for AD as both oral and topical treatment ameliorates AD-like symptoms in the murine model.

Exogenous drug-induced mouse models of atopic dermatitis

Atopic dermatitis (AD) is an inflammatory skin disease characterized by intense pruritus. AD is harmful to both children and adults, but its pathogenic mechanism has yet to be fully elucidated. The development of mouse models for AD has greatly contributed to its study and treatment. Among these models, the exogenous drug-induced mouse model has shown promising results and significant advantages. Until now, a large amount of AD-related research has utilized exogenous drug-induced mouse models, leading to notable advancements in research. This indicates the crucial significance of applying such models in AD research. These models exhibit diverse characteristics and are highly complex. They involve the use of various strains of mice, diverse types of inducers, and different modeling effects. However, there is currently a lack of comprehensive comparative studies on exogenous drug-induced AD mouse models, which hinders researchers' ability to choose among these models. This paper provides a comprehensive review of the features and mechanisms associated with various exogenous drug-induced mouse models, including the important role of each cytokine in AD development. It aims to assist researchers in quickly understanding models and selecting the most suitable one for further investigation.

Anti-Atopic Dermatitis Effect of TPS240, a Novel Therapeutic Peptide, via Suppression of NF-κB and STAT3 Activation

Atopic dermatitis (AD) is a relapsing skin disease with persistent inflammation as a causal factor for symptoms and disease progression. Current therapies provide only temporary relief and require long-term usage accompanied by side effects due to persistent relapses. A short peptide, TPS240, has been tested for its potential to subside AD. In this study, we confirmed the anti-atopic effect of TPS240 in vivo and in vitro using a DNCB-induced AD mouse model and TNF-α/IFN-γ-stimulated HaCaT cells. In the AD mouse model, topical treatment with TPS240 diminished AD-like skin lesions and symptoms such as epidermal thickening and mast cell infiltration induced by DNCB, similar to the existing treatment, dexamethasone (Dex). Furthermore, skin atrophy, weight loss, and abnormal organ weight changes observed in the Dex-treated group were not detected in the TPS240-treated group. In TNF-α/IFN-γ-stimulated HaCaT cells, TPS240 reduced the expression of the inflammatory chemokines CCL17 and CCL22 and the pruritic cytokines TSLP and IL-31 by inhibiting NF-κB and STAT3 activation. These results suggest that TPS240 has an anti-atopic effect through immunomodulation of AD-specific cytokines and chemokines and can be used as a candidate drug for the prevention and treatment of AD that can solve the safety problems of existing treatments.

Beneficial Effects of Two Hydrogen Sulfide (H2S)-Releasing Derivatives of Dexamethasone with Antioxidant Activity on Atopic Dermatitis in Mice

Hydrogen sulfide (H₂S) is particularly produced in the skin, where it participates in the regulation of inflammation, pruritus, cytoprotection, scarring, and angiogenesis. In this study, we compared the effects of dexamethasone (Dex) with two H₂S-releasing Dex derivatives in a murine model of atopic dermatitis (AD) induced by topical application of 2,4-dinitrochlorobenzene (DNCB). After sensitization with DNCB, the animals were topically treated for five consecutive days with either the H₂S-releasing compounds 4-hydroxy-thiobenzamide (TBZ) and 5-(p-hydroxyphenyl)-1,2-dithione-3-thione (ADT-OH), Dex, or the derivatives Dex-TBZ or Dex-ADT. Topical treatment with equimolar doses of either Dex, Dex-TBZ, or Dex-ADT resulted in similar reductions in dermatitis score, scratching behavior, edema, eosinophilia, splenomegaly, and histological changes. In contrast with Dex, the H₂S-releasing derivatives prevented IL-4 elevation and oxidative modification of skin proteins. On an equimolar dose basis, Dex-TBZ, but not Dex-ADT, promoted the elevation of endogenous H₂S production and GPx activity. Neither Dex-TBZ nor Dex-ADT decreased GR activity or caused hyperglycemia, as observed with Dex treatment. We conclude that the presence of H₂S-releasing moieties in the Dex structure does not interfere with the anti-inflammatory effects of this corticosteroid and adds beneficial therapeutical actions to the parent compound.

Parnassin, a Novel Therapeutic Peptide, Alleviates Skin Lesions in a DNCB-Induced Atopic Dermatitis Mouse Model

Atopic dermatitis (AD) is a chronic inflammatory skin disease which requires continuous treatment due to its relapsing nature. The current treatment includes steroids and nonsteroidal agents targeting inflammation but long-term administration causes various side effects such as skin atrophy, hirsutism, hypertension and diarrhea. Thus, there is an unmet need for safer and effective therapeutic agents in the treatment of AD. Peptides are small biomolecule drugs which are highly potent and remarkably have less side effects. Parnassin is a tetrapeptide with predicted anti-microbial activity curated from Parnassius bremeri transcriptome data. In this study, we confirmed the effect of parnassin on AD using a DNCB-induced AD mouse model and TNF-α/IFN-γ-stimulated HaCaT cells. In the AD mouse model, topical administration of parnassin improved skin lesions and symptoms in AD mice, such as epidermal thickening and mast cell infiltration, similar to the existing treatment, dexamethasone, and did not affect body weight, or the size and weight of spleen. In TNF-α/IFN-γ-stimulated HaCaT cells, parnassin inhibited the expression of Th2-type chemokine CCL17 and CCL22 genes by suppressing JAK2 and p38 MAPK signaling kinases and their downstream transcription factor STAT1. Parnassin also significantly reduced the gene expression of TSLP and IL-31, which are pruritus-inducing cytokines. These findings suggested that parnassin alleviates AD-like lesions via its immunomodulatory effects and can be used as a candidate drug for the prevention and treatment of AD because it is safer than existing treatments.

Management of Atopic Dermatitis Via Oral and Topical Administration of Herbs in Murine Model: A Systematic Review

Over the past few decades, complementary and alternative medicine (CAM) using herbs, or their active constituents have garnered substantial attention in the management of a chronic and relapsing inflammatory skin disorder called atopic dermatitis (AD), particularly in attenuating disease recurrence and maintaining long-term remission. In Eastern Asian countries including China, Korea and Taiwan, herbal medicine available in both topical and oral preparation plays a significant role in treating skin diseases like AD as they possibly confer high anti-inflammatory properties and immunomodulatory functions. Conventional murine models of AD have been employed in drug discovery to provide scientific evidence for conclusive and specific pharmacological effects elicited by the use of traditional herbs and their active constituents. Coupled with the goal to develop safe and effective novel therapeutic agents for AD, this systematic review consists of a summary of 103 articles on both orally and topically administered herbs and their active constituents in the murine model, whereby articles were screened and selected via a specialized framework known as PICO (Population, Intervention, Comparator and Outcome). The objectives of this review paper were to identify the efficacy of oral and topical administered herbs along with their active constituents in alleviating AD and the underlying mechanism of actions, as well as the animal models and choice of inducer agents used in these studies. The main outcome on the efficacy of the majority of the herbs and their active constituents illustrated suppression of Th2 response as well as improvements in the severity of AD lesions, suppression of Immunoglobulin E (IgE) concentration and mast cell infiltration. The majority of these studies used BALB/c mice followed by NC/Nga mice (commonly used gender-male; commonly used age group - 6-8 weeks). The most used agent in inducing AD was 2, 4-Dinitrochlorobenzene (DNCB), and the average induction period for both oral and topical administered herbs and their active constituents in AD experiments lasted between 3 and 4 weeks. In light of these findings, this review paper could potentially assist researchers in exploring the potential candidate herbs and their active constituents using murine model for the amelioration of AD.

Structure and Biological Activity of Ergostane-Type Steroids from Fungi

Mushrooms are known not only for their taste but also for beneficial effects on health attributed to plethora of constituents. All mushrooms belong to the kingdom of fungi, which also includes yeasts and molds. Each year, hundreds of new metabolites of the main fungal sterol, ergosterol, are isolated from fungal sources. As a rule, further testing is carried out for their biological effects, and many of the isolated compounds exhibit one or another activity. This study aims to review recent literature (mainly over the past 10 years, selected older works are discussed for consistency purposes) on the structures and bioactivities of fungal metabolites of ergosterol. The review is not exhaustive in its coverage of structures found in fungi. Rather, it focuses solely on discussing compounds that have shown some biological activity with potential pharmacological utility.

The Suppressive Effect of Mamiran Cream on Atopic Dermatitis-Like Skin Lesions In Vivo

BACKGROUND

The Chinese herbal formula Mamiran cream (MMC) has been known for its ameliorative effects on diverse skin diseases, such as eczema. Atopic dermatitis (AD; eczema) is a chronic recurrent skin disease dominated by T-helper type 2-driven inflammation (Th2).

OBJECTIVE

In this study, the inhibitory effect of MMC on AD was investigated in vivo.

METHODS

An animal model was established by sensitization with 2,4-dinitrochlorobenzene (DNCB) on the skin of SD rats. Cutaneous administration of MMC was applied, and its mechanism of action was investigated via RT-PCR and IHC assay.

RESULT

Our data showed that topical application of MMC reduced the skin severity scores and alleviated the histological changes. Furthermore, immunohistochemical analysis demonstrated that MMC significantly decreased the levels of Th2 cytokine IL-5 and IL-4Ra in the skin lesion. In addition, it was demonstrated that MMC downregulated the mRNA expression of TNF-α, IL-1β, IL-6, IL-10, and TLR4. Moreover, MMC inhibited the activation of NF-κB, JNK1, and STAT6 pathways in skin lesions.

CONCLUSIONS

Our findings suggest that MMC exhibits the inhibitory effect on AD, suggesting that MMC may be a potential therapeutic agent for this atopic disorder.

Oleanolic Acid Alleviates Atopic Dermatitis-like Responses In Vivo and In Vitro

Oleanolic acid (OA) is a pentacyclic triterpenoid, abundantly found in plants of the Oleaceae family, and is well known for its beneficial pharmacological activities. Previously, we reported the inhibitory effect of OA on mast cell-mediated allergic inflammation. In this study, we investigated the effects of OA on atopic dermatitis (AD)-like skin lesions and its underlying mechanism of action. We evaluated the inhibitory effect of OA on AD-like responses and the possible mechanisms using a 1-chloro-2,4-dinitrochlorobenzene (DNCB)-induced AD animal model and tumor necrosis factor (TNF)-α/interferon (IFN)-γ-stimulated HaCaT keratinocytes. We found that OA has anti-atopic effects, including histological alterations, on DNCB-induced AD-like lesions in mice. Moreover, it suppressed the expression of Th2 type cytokines and chemokines in the AD mouse model and TNF-α/IFN-γ-induced HaCaT keratinocytes by blocking the activation of serine-threonine kinase Akt, nuclear factor-κB, and the signal transducer and activator of transcription 1. The results demonstrate that OA inhibits AD-like symptoms and regulates the inflammatory mediators; therefore, it may be used as an effective and attractive therapeutic agent for allergic disorders, such as AD. Moreover, the findings of this study provide novel insights into the potential pharmacological targets of OA for treating AD.

Sarsasapogenin and fluticasone combination improves DNFB induced atopic dermatitis lesions in BALB/c mice

OBJECTIVE

Atopic dermatitis (AD) is a pruritic, chronic, relapsing inflammatory skin disease. The research aims to study the effects of Sarsasapogenin and its combination with Fluticasone in 2, 4-Dinitrofluorobenzene (DNFB) induced atopic dermatitis in BALB/c mice.

MATERIAL AND METHODS

Thirty male Balb/c mice were divided into 5 groups: (i) Normal control (NC), (ii) Disease control (DNFB), (iii) Sarsasapogenin (SG) (50 µg/mice), (iv) Fluticasone (FC) (50 µg/mice), (v) Sarsasapogenin + Fluticasone (SG + FC) combination (25 µg/mice). Dermatitis was induced by repeated application of DNFB in Balb/c mice. On topical application of SG, FC, and SG + FC combination on the ear and skin lesions, body weight, ear weight, ear thickness, erythema score, spleen weight, cytokines, immunoglobulin E (IgE) levels, nitric oxide (NO) level, hematological parameters, and oxidative stress markers were evaluated. Histological analysis of the ear tissue was also done.

RESULTS

The results stated that SG and SG + FC treatment to mice considerably decrease the ear weight, ear thickness, spleen weight, serum IgE, cytokines, NO levels, and restoration of antioxidant stress markers with elevation in the hematological parameters. The observations were further confirmed by histopathological analysis of ear tissue.

CONCLUSION

These data specify that SG has been demonstrated as a probable therapy for the treatment of allergic skin diseases in combination with FC by decreasing its dose from 50 to 25 µg/mice to avoid the chronic side effects of FC. Hence, it can be concluded that SG and SG + FC combination significantly improved the AD-like symptoms in the DNFB sensitized mice through mitigating the production of proinflammatory mediators and restoration of oxidative stress markers.

Suppressive effect of 1,4-anhydro-4-seleno-D-talitol (SeTal) on atopic dermatitis-like skin lesions in mice through regulation of inflammatory mediators

BACKGROUND

Atopic dermatitis (AD) is a multifactorial chronic inflammatory disease that affects ∼20 % of children and 3% of adults globally and is generally treated by the topical application of steroidal drugs that have undesirable side-effects. The development of alternative therapies is therefore an important objective. The present study investigated the effects of topical treatment with a novel water-soluble selenium-containing carbohydrate derivative (4-anhydro-4-seleno-D-tatitol, SeTal) on the symptoms and inflammatory parameters in an AD mouse model.

METHODS

Mice were sensitized by applying 2,4-dinitrochlorobenzene (DNCB) to their dorsal skin on days 1-3, then further challenged on their ears and dorsal skin on days 14, 17, 20, 23, 26, and 29. SeTal (1 and 2%) or hydrocortisone (1%) was applied topically to the backs of the mice from days 14-29, and skin severity scores and scratching behavior determined on day 30. The mice were euthanized, and their ears and dorsal skin removed to quantify inflammatory parameters, edema, myeloperoxidase (MPO) activity, and AD-associated cytokines (tumor necrosis factor alpha (TNF-α), interleukins (IL)-18, and IL-33).

RESULTS

DNCB treatment induced skin lesions and increased the scratching behavior, ear edema, MPO activity (ear and dorsal skin), and cytokine levels in dorsal skin. Topical application of SeTal improved inflammatory markers (cytokine levels and MPO activity), cutaneous severity scores, and scratching behavior.

CONCLUSION

The efficacy of SeTal was satisfactory in the analyzed parameters, showing similar or better results than hydrocortisone. SeTal appears to be therapeutically advantageous for the treatment and control of AD.

Anti-Inflammatory Activity of a Medicinal Herb Extract Mixture, HM-V, on an Animal Model of DNCB-Induced Chronic Skin Inflammation

Chronic inflammatory skin diseases, such as atopic dermatitis, are caused by the accumulation of immune cells and the overproduction of chemokines, including CCL17 and CCL22, due to the activation of pro-inflammatory cytokines secreted from keratinocytes. In the present study, the inhibitory activity of HM-V on tumor necrosis factor alpha (TNF-α)/interferon gamma (IFN-γ)-induced pro-inflammatory cytokines was examined in human keratinocytes (HaCaTs) and 2,4-dinitrofluorobenzene (DNCB)-induced chronic skin contact dermatitis animal models. Traditional Asian medicinal herb extracts mixture (HM-V), which have been extensively used in Asian medicine, were utilized. In TNF-α/IFN-γ-induced HaCaTs, HM-V strongly inhibited mRNA and protein expression of CCL17 and CCL22 in a concentration-dependent manner. The expression of pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6 was also inhibited. Therefore, localized administration of HM-V in the DNCB-induced animal model alleviated immune cell deposition and skin inflammation. The results indicate that HM-V exerts inhibitory effects on keratinocyte production of CCL17 and CCL22. Furthermore, HM-V may be a useful anti-inflammatory agent for the prevention and treatment of inflammatory skin diseases.

Δ8(14)-Ergostenol Glycoside Derivatives Inhibit the Expression of Inflammatory Mediators and Matrix Metalloproteinase

Arthritis is a chronic inflammatory disease accompanied by pathological reactions such as swelling, redness, fever, and pain in various joint areas. The drugs currently available to treat arthritis are associated with diverse side-effects. Therefore, there is a need for safer and more effective treatments to alleviate the inflammation of arthritis with fewer side-effects. In this study, a new sterol, Δ⁸⁽¹⁴⁾-ergostenol, was discovered, and its glycosides were synthesized and found to be more efficient in terms of synthesis or anti-inflammatory activity than either spinasterol or 5,6-dihydroergosterol is. Among these synthetic glycosides, galactosyl ergostenol inhibited the expression of inflammatory mediators in TNF-α-stimulated FLS and TNF-α-induced MMPs and collagen type II A1 degradation in human chondrocytes. These results suggest the new galactosyl ergostenol as a treatment candidate for arthritis.

Phytosterols: Targeting Neuroinflammation in Neurodegeneration

Plant-derived sterols, phytosterols, are well known for their cholesterol-lowering activity in serum and their anti-inflammatory activities. Recently, phytosterols have received considerable attention due to their beneficial effects on various non-communicable diseases, and recommended use as daily dietary components. The signaling pathways mediated in the brain by phytosterols have been evaluated, but little is known about their effects on neuroinflammation, and no clinical studies have been undertaken on phytosterols of interest. In this review, we discuss the beneficial roles of phytosterols, including their attenuating effects on inflammation, blood cholesterol levels, and hallmarks of the disease, and their regulatory effects on neuroinflammatory disease pathways. Despite recent advancements made in phytosterol pharmacology, some critical questions remain unanswered. Therefore, we have tried to highlight the potential of phytosterols as viable therapeutics against neuroinflammation and to direct future research with respect to clinical applications.

Topical application with conjugated linoleic acid ameliorates 2, 4-dinitrofluorobenzene-induced atopic dermatitis-like lesions in BALB/c mice

Atopic dermatitis (AD) is a multifactorial chronic inflammatory skin disease characterized by skin barrier dysfunction, eczematous lesions, pruritus, and abnormal immune responses. In this study, we assessed the therapeutic effect of topical applied conjugated linoleic acid (CLA) on a murine AD model that was developed by repetitive applications of 2, 4-dinitrofluorobenzene (DNFB). 2% or 5% CLA could markedly ameliorate AD-like skin lesions, scratching behaviour and skin inflammation as evidenced by the reduced inflammatory blood cells, IgE and Th2-related cytokine levels, and the infiltration of mast cells and inflammatory cells to the dermal tissues. Moreover, topical application with CLA modulated skin barrier repair including maintaining a balanced skin pH and increasing skin hydration, partially mediated by upregulating skin barrier-related protein, filaggrin (FLG). In addition, topical CLA significantly dose-dependently inhibited pro-inflammatory cytokines including interleukin (IL)-6, IL-1β, tumour necrosis factor (TNF)-α and pro-inflammatory enzyme expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in inflamed mice skin. Its anti-inflammatory effect was associated with the inhibition of DNFB-stimulated IκBα and NF-κB p65 phosphorylation in mouse skin. Taken together, our results suggest that locally applied CLA exerts potentially protective effects against AD lesional skin at least in part, due to regulation of skin barrier function and inflammatory response.

Oral Administration of Sargassum horneri Improves the HDM/DNCB-Induced Atopic Dermatitis in NC/Nga Mice

The present study investigated the protective effects of Sargassum horneri (S. horneri) ethanol extract (SHE) against atopic dermatitis (AD), known as an abnormal immune response in house dust mite (HDM)/2,4-dinitrochlorobenzene (DNCB)-stimulated NC/Nga mice. The oral administration of SHE attenuated the AD symptoms, including the skin dermatitis severity, transepidermal water loss (TEWL), and ear edema in HDM/DNCB-stimulated mice. Moreover, the histological analysis revealed that SHE improved epidermal hyperplasia and hyperkeratosis, and reduced the dermal infiltrations of mast cells and eosinophils. Moreover, SHE downregulated the expression levels of cytokines (interleukin (IL)-6, IL-10, and interferon (IFN)-γ) and chemokines (Regulated on Activation, Normal T Cell Expressed and Secreted (RANTES), Eotaxin, and Thymus and activation-regulated chemokine (TARC)) by decreasing the expression levels of atopic initiators (IL-25 and IL-33) in HDM/DNCB-stimulated skin. The oral administration of SHE decreased the spleen size, reducing expression levels of AD-related cytokines (IL-4, IL-5, IL-6, IL-10, IL-13, IFN-γ, and TARC) by regulating the expressions of Tbx21 (T-bet), GATA Binding Protein 3 (GATA-3), and Signal transducer and activator of transcription 3 (STAT3). Moreover, SHE significantly attenuated the serum immunoglobulin (Ig)G1 and IgG2a levels in HDM/DNCB-stimulated mice. Collectively, these results suggest that S. horneri could be an ingredient of functional food against abnormal immune response.

Solanum nigrum Linne improves DNCB‑induced atopic dermatitis‑like skin disease in BALB/c mice

The present study aimed to investigate the effects of Solanum nigrum Linne (SNL) in a model of 1-chloro-2,4-dinitrobenzene (DNCB)-induced atopic dermatitis (AD) and in TNF-α/IFN-γ-stimulated HaCaT cells. AD is a chronic inflammatory skin disease and is characterized by erythema, edema, increased pruritus and eczema. Steroids are most commonly used for anti-inflammatory therapy; however, their long-term use is limited due to side-effects, such as osteoporosis, brittle skin, muscle weaknesses and diabetes. Therefore, patients with AD require alternative treatment strategies. In previous studies, SNL has been reported to be effective against oxidants and cancer. However, to the best of our knowledge, the effects of SNL on AD have not yet been investigated. The present study examined the effects of SNL ethanol extract on a model of DNCB induced AD and on TNF-α/IFN-γ-stimulated HaCaT cells. The skin tissue was sectioned to measure the thicknesses of the epidermis and dermis, as well as the numbers of eosinophils, mast cells and CD8 infiltration by H&E, toluidine blue, Masson's trichrome and IHC staining. ELISA was performed using serum to measure IgE levels. The present study also examined the expression of various inflammatory cytokines, MAPK and NF-κB in TNF-α/IFN-γ-stimulated HaCaT cells. SNL significantly reduced the levels of cytokines released from HaCaT cells stimulated with TNF-α/IFN-γ. SNL also significantly reduced the levels of p-p38 at 30 min and significantly reduced the activation of NF-κB in a time course experiment. In addition, SNL significantly reduced the level of serum IgE and dermal thickness and the infiltration of mast cells and CD8 in the BALB/c mouse model of DNCB-induced AD. The results of the current study suggest that SNL exerts a suppressive effect on pro-inflammatory cytokines in vitro and in vivo through the regulation of the immune system.

Comparative Study of the Effect of 5,6-Dihydroergosterol and 3-epi-5,6-dihydroergosterol on Chemokine Expression in Human Keratinocytes

5,6-Dihydroergosterol-glucose is an organic synthetic derivative of spinasterol-glucose, which has potent anti-inflammatory activity. We previously synthesized alpha and beta anomers of DHE-glycosides and compared their inhibitory activity on CCL17 and CCL22 mRNA expression induced by TNF-α/IFN-γ in activated HaCaTs. Recently, we synthesized a new type of DHE-glycosides, 3-epi-5,6-dihydroergosterol(3-epi-DHE)-glycosides, and compared its inhibitory activity on mRNA expression levels of CCL17 and CCL22 in TNF-α/IFN-γ-induced HaCaT. DHE-Xly did not affect TNF-α/IFN-γ induced CCL17 and CCL22 mRNA expression in HaCaTs, however, 3-epi-DHE-Xly strongly inhibited TNF-α/IFN-γ induced CCL17 and CCL22 mRNA expression levels in human keratinocytes. These results provide important clues for development of chronic dermatitis treatment via inhibition of chemokine expression using DHE derivatives.

Polyozellin alleviates atopic dermatitis-like inflammatory and pruritic responses in activated keratinocytes and mast cells

Polyozellus multiplex is an edible mushroom that offers beneficial pharmacological effects against intestinal inflammation and cancer. Previous studies have demonstrated that polyozellin, a major component of P. multiplex, has therapeutic activities against inflammation, cancer, and oxidative stress-related disorders. This study aimed to determine the pharmacological effects of polyozellin on inflammatory and pruritic responses, the major symptoms of atopic dermatitis (AD), and to define its underlying mechanism of action. Our results showed that polyozellin inhibited the expression of inflammatory cytokines and chemokines through blockade of signal transducer and activator of transcription 1 and nuclear factor-κB in activated keratinocytes, the major cells involved in AD progression. Based on the histological and immunological analyses, oral treatment with polyozellin attenuated the Dermatophagoides farinae extract (DFE)/2,4-dinitrochlorobenzene (DNCB)-induced atopic inflammatory symptoms in the skin. Pruritus is an unpleasant sensation for AD patients that causes scratching behavior and ultimately exacerbates the severity of AD. To find a possible explanation for the anti-pruritic effects of polyozellin, we investigated its effects on mast cells and mast cell-derived histamines. Oral treatment with polyozellin reduced the DFE/DNCB-induced tissue infiltration of mast cells, the serum histamine levels, and the histaminergic scratching behaviors. Additionally, polyozellin decreased the immunoglobulin E-stimulated degranulation of mast cells. Taken together, the findings of this study provide us with novel insights into the potential pharmacological targets of polyozellin for treating AD by inhibiting the inflammatory and pruritic responses.

Inhibitory Effects of a Novel Chrysin-Derivative, CPD 6, on Acute and Chronic Skin Inflammation

The skin is an important physiological barrier against external stimuli, such as ultraviolet radiation (UV), xenobiotics, and bacteria. Dermal inflammatory reactions are associated with various skin disorders, including chemical-induced irritation and atopic dermatitis. Modulation of skin inflammatory response is a therapeutic strategy for skin diseases. Here, we synthesized chrysin-derivatives and identified the most potent derivative of Compound 6 (CPD 6). We evaluated its anti-inflammatory effects in vitro cells of macrophages and keratinocytes, and in vivo dermatitis mouse models. In murine macrophages stimulated by lipopolysaccharide (LPS), CPD 6 significantly attenuated the release of inflammatory mediators such as nitric oxide (NO) (IC₅₀ for NO inhibition: 3.613 μM) and other cytokines. In cultured human keratinocytes, CPD 6 significantly attenuated the release of inflammatory cytokines induced by the combination of IFN-γ and TNF-α, UV irradiation, or chemical irritant stimulation. CPD 6 inhibited NFκB and JAK2/STAT1 signaling pathways, and activated Nrf2/HO-1 signaling. In vivo relevancy of anti-inflammatory effects of CPD 6 was observed in acute and chronic skin inflammation models in mice. CPD 6 showed significant anti-inflammatory properties both in vitro cells and in vivo dermatitis animal models, mediated by the inhibition of the NFκB and JAK2-STAT1 pathways and activation of Nrf2/HO-1 signaling. We propose that the novel chrysin-derivative CPD 6 may be a potential therapeutic agent for skin inflammation.

Comparison of the Inhibitory Activities of 5,6-Dihydroergosterol Glycoside α- and β-Anomers on Skin Inflammation

Chronic skin inflammatory diseases, such as atopic dermatitis, are associated with a dysfunctional skin barrier due to an increase in various inflammatory stimuli, for instance inflammatory cytokines and chemokines. In particular, CCL17 and CCL22 expression is increased in patients with chronic skin inflammation. In this study, we synthesized several α- and β-anomers of dihydroergosterol (DHE)-glycosides and assessed their effects on CCL17 and CCL22 expression. We confirmed that the β-anomers of DHE-glycosides were superior to α-anomers of DHE-glycosides in inhibiting CCL17 and CCL22 mRNA and protein expression. In addition, we determined that DHE-glycoside β-anomers showed strong inhibitory activity towards pro-inflammatory cytokine mRNA and protein expression, including that of TNF-α, IL-6, and IL-1β- in stimulated HaCaT cells. These results imply that DHE-glycoside α- and β-anomers should be separated during synthesis of drugs for chronic skin inflammation. Our results also suggest that β-anomers of DHE-glycosides may play an important role as new drugs for chronic skin inflammation because of their ability to inhibit the skin inflammatory biomarker proteins CCL17 and CCL22.

Anti-Allergic and Anti-Inflammatory Effects of Kuwanon G and Morusin on MC/9 Mast Cells and HaCaT Keratinocytes

Atopic dermatitis (AD) is a prevalent chronic inflammatory skin disease. The use of immunomodulatory corticosteroids in AD treatment causes adverse side effects. Therefore, novel natural anti-inflammatory therapeutics are needed. The aim of the present study was to investigate the anti-allergic and anti-inflammatory activities of kuwanon G and morusin. To investigate the effect of kuwanon G and morusin on skin inflammation, enzyme-linked immunosorbent assays (ELISA) to quantitate secreted (RANTES/CCL5), thymus- and activation-regulated chemokine (TARC/CCL17), and macrophage-derived chemokine (MDC/CCL22) were performed, followed by Western blotting to measure the phosphorylation of signal transducer and activator of transcription 1 (STAT1) and nuclear transcription factor-κB (NF-κB) p65 in tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ)-stimulated HaCaT keratinocytes. In order to evaluate the anti-allergic effects, ELISA to quantify histamine and leukotriene C₄ (LTC₄) production and Western blotting to measure 5-lipoxygenase (5-LO) activation were performed using PMA and A23187-stimulated MC/9 mast cells. Kuwanon G reduced the release of RANTES/CCL5, TARC/CCL17, and MDC/CCL22 via down-regulation of STAT1 and NF-κB p65 signaling in TNF-α and IFN-γ-stimulated HaCaT keratinocytes. Kuwanon G also inhibited histamine production and 5-LO activation in PMA and A23187-stimulated MC/9 mast cells. Morusin inhibited RANTES/CCL5 and TARC/CCL17 secretion via the suppression of STAT1 and NF-κB p65 phosphorylation in TNF-α and IFN-γ-stimulated HaCaT keratinocytes, and the release of histamine and LTC₄ by suppressing 5-LO activation in PMA and A23187-stimulated MC/9 mast cells. Kuwanon G and morusin are potential anti-inflammatory mediators for the treatment of allergic and inflammatory skin diseases such as AD.

Anti-inflammatory effect of collagen tripeptide in atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a chronic, pruritic inflammatory skin disease in which type 2 allergic inflammation plays an important role. Collagen tripeptide (CTP) is a functional collagen fraction with a high content of Gly-X-Y tripeptides.

OBJECTIVE

To examine the effect of CTP on inflammation in AD.

METHODS

Levels of inflammatory cytokines and chemokines, such as thymus- and activation-regulated chemokine (TARC), macrophage-derived chemokine, and thymic stromal lymphopoietin (TSLP), were examined in human keratinocytes supplemented with or without CTP under AD-like inflammation. To evaluate the functional effect of CTP, a migration assay was performed using the supernatants of cultured keratinocytes treated with CTP. The signaling pathway for CTP inhibitory activity was also determined. Additionally, we conducted a clinical trial with seventeen AD patients who were assigned randomly to receive daily for 12 weeks either 3.9g of a CTP product or normal collagen peptides (CP). The eruption area, severity scoring of atopic dermatitis (SCORAD), skin hydration, transepidermal water loss (TEWL), and itching score were evaluated. The levels of TARC, serum IgE, lactate dehydrogenase, and eosinophil counts at week 12 were also compared with those at the start of administration.

RESULTS

In human keratinocytes, TARC and TSLP mRNA and protein levels were inhibited significantly by CTP treatment under AD-like inflammation. Supernatants obtained from CTP-treated keratinocytes inhibited cell migration. STAT1 phosphorylation was significantly decreased by CTP in a dose-dependent manner. In the clinical trial, 13 patients (7 for CTP, 6 for CP) completed the study. The eruption area, SCORAD, and TEWL at week 12 were reduced significantly compared with the initial values in the CTP but not CP group. A significant reduction in the serum TARC level was observed only in the CTP group at week 12. Other blood parameters were not improved in either group.

CONCLUSION

CTP may have therapeutic benefit for AD by inhibiting type 2-skewed allergic inflammation.

Anti‑inflammatory effect of Amomum xanthioides in a mouse atopic dermatitis model

Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disorder. The present study investigated the effects of Amomum xanthioides extract (AXE) on AD‑like skin inflammation using a Dermatophagoides farinae extract (DFE) and 2,4‑dinitrochlorobenzene (DNCB)‑induced mouse AD model. Hematoxylin and eosin staining results demonstrated that repeated DFE/DNCB exposure markedly increased the thickening of the dermis and epidermis, in addition to the infiltration of eosinophils and mast cells. However, oral administration of AXE reduced these histopathological alterations in a dose‑dependent manner. Elevated serum histamine, total and DFE‑specific immunoglobulin E (IgE), and IgG2a were also decreased by treatment with AXE. In addition, reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) results demonstrated that the mRNA expression of tumor necrosis factor (TNF)‑α, interferon (IFN)‑γ, interleukin (IL)‑4, IL‑13, IL‑31 and IL‑17A was reduced in ear skin following AXE administration in AD mice. Fluorescence‑activated cell sorting demonstrated that the population of CD4+/IL‑4+, CD4+/IFN‑γ+ and CD4+/IL‑17A+ cells in draining lymph nodes was also significantly decreased in AXE‑treated mice compared with AD mice without AXE treatment. Furthermore, keratinocytes that were stimulated with TNF‑α and IFN‑γ exhibited increased gene expression of pro‑inflammatory cytokines and chemokines, including TNF‑α, IL‑1β, IL‑6, IL‑8, C‑C motif chemokine ligand (CCL)17 and CCL22, as determined by RT‑qPCR. However, upregulation of these genes was reduced by AXE pretreatment. Based on these results, we hypothesize that AXE may be useful in the treatment of allergic skin inflammation, particularly AD.

Bortezomib, a proteasome inhibitor, alleviates atopic dermatitis by increasing claudin 1 protein expression

Atopic dermatitis (AD) is a chronic inflammatory skin disease. Many studies investigating AD pathogenesis and its therapy have been conducted but none have been successful. One of the causes of AD is dysfunction of tight junctions through reduction of claudin 1 expression in the epidermal barrier of the skin. In the present study, we investigated the role of bortezomib (BTZ) in the restoration of the reduced expression of claudin 1. Immunoblot and immunofluorescence analyses revealed that BTZ increased the protein expression level of claudin 1 in the human keratinocyte cell line HaCaT, thereby forming paracellular barriers. Furthermore, repeated application of BTZ alleviated atopic symptoms on the backs and ears of 2, 4-dinitrochlorobenzene (DNCB)-induced AD mice, and led to the formation of normal tight junctions in the epidermal barrier of DNCB-induced mice skin. Taken together, these results demonstrate that BTZ-induced claudin 1 expression may be a valuable therapeutic approach for AD.

Global gene regulation during activation of immunoglobulin class switching in human B cells

Immunoglobulin class switch recombination (CSR) to IgE is a tightly regulated process central to atopic disease. To profile the B-cell transcriptional responses underlying the activation of the germinal centre activities leading to the generation of IgE, naïve human B-cells were stimulated with IL-4 and anti-CD40. Gene expression and alternative splicing were profiled over 12 days using the Affymetrix Human Exon 1.0 ST Array. A total of 1,399 genes, forming 13 temporal profiles were differentially expressed. CCL22 and CCL17 were dramatically induced but followed a temporal trajectory distinct from classical mediators of isotype switching. AICDA, NFIL3, IRF4, XBP1 and BATF3 shared a profile with several genes involved in innate immunity, but with no recognised role in CSR. A transcription factor BHLHE40 was identified at the core of this profile. B-cell activation was also accompanied by variation in exon retention affecting >200 genes including CCL17. The data indicate a circadian component and central roles for the Th2 chemokines CCL22 and CCL17 in the activation of CSR.

Clinical categories of exaggerated skin reactions to mosquito bites and their pathophysiology

Mosquito bites are skin irritating reactions, which usually resolve spontaneously without intensive medical care. However, in certain situations, mosquito bites may form a more vicious reaction, sometimes accompanying fever and systemic symptoms. In such cases, the presence of rare hematological disorders, abnormalities in eosinophils and/or association with Epstein-Barr virus (EBV) may underlie. Importantly, hypersensitivity to mosquito bites (HMB), which is characterized by necrotic skin reactions to mosquito bites with various systemic symptoms, is often observed in association with EBV infection and natural killer (NK) cell lymphoproliferative disorder. Exaggerated skin reaction to mosquito bites is also seen in Wells' syndrome. While strong Th2-skewing immune dysregulation is apparent in the patients, they also show robust CD4(+) T cell proliferation in response to mosquito salivary gland extracts, indicating close association between Wells' syndrome and mosquito bites. Similar skin reaction to mosquito bites is also noticed in certain types of B cell neoplasm, although the role of B cells in this peculiar reaction to mosquito bites is yet to be elucidated. In this review, we will discuss the current knowledge of exaggerated reaction toward mosquito bites seen in conjunction with these unique hematological disorders, and examine the scientific studies and observations reported in previous literatures to organize our current understanding of the pathogenesis of this distinct disorder.