Dermatophagoides farinae extract induces severe atopic dermatitis in NC/Nga mice,which is effectively suppressed by the administration of tacrolimus ointment

Atopic dermatitis (AD) is a chronic inflammatory skin disease, which is accompanied by marked increases in the levels of inflammatory cells, including mast cells and eosinophils as well as T cells and macrophages. To investigate the expression pattern of chemokines in AD, a house dust mite, Dermatophagoides farinae extracts (DfE)-induced NC/Nga AD model was developed in mice, and this model was used to determine the expression levels of chemokines in atopic lesions using DNA microarrays and RT-PCR. When NC/Nga mice were repeatedly treated with DfE for 4 to 7 weeks on the back skin, the mRNA expression levels of CCL20/LARC, CCL24/eotaxin-2, CCL17/TARC, and CCL11/eotaxin-1 were markedly induced and lesser of CCL2/MCP-1, within the inflammatory lesion of the back skin. Immunohistochemical staining revealed the expression of these chemokines in the epidermis and dermis of DfE-treated NC/Nga mice. Interestingly, repeated application of tacrolimus ointment potently inhibited DfE-induced atopic dermatitis in NC/Nga mice concomitant with the inhibition of these changes in chemokine gene and protein expression levels particularly of CCL20/LARC, CCL17/TARC, and CCL11/eotaxin-1. These data indicate that severe atopic dermatitis induced by DfE accompanies elevated chemokine levels, and it was proposed that tacrolimus ointment is beneficial for the treatment of severe AD.     

Topical application of Pleurotus eryngii extracts inhibits 2,4-dinitrochlorobenzene-induced atopic dermatitis in NC/Nga mice by the regulation of Th1/Th2 balance

Pleurotus eryngii is a nutritional and medicinal food rich in polysaccharides that enhance the host immune system as a response to various diseases. The present study investigated the effects of P. eryngii extracts (PEE) on the progress of atopic dermatitis (AD)-like skin lesions in NC/Nga mice induced by 2,4-dinitrochlorobenzene (DNCB). We evaluated skin dermatitis severity, ear thickness, histopathological examination, and cytokines level in DNCB-applied mice treated with PEE. Continuous treatment of PEE inhibited the development of the AD-like skin lesions. PEE suppressed DNCB-induced dermatitis severity, serum level of IgE and thymus and activation-regulated chemokine (TARC), and mRNA expression of TNF-α, INF-γ, IL-4, IL-5, and IL-13 in mice. In addition, PEE reduced thickness of the dermis and dermal infiltration of inflammatory cells and mast cells in histopathological examination. These results indicate that PEE inhibits allergic contact dermatitis through the modulating of T helper (Th)1 and Th2 responses and diminishing the inflammatory cells and mast cells infiltration in the skin lesions in NC/Nga mice.     

Platycodi Radix suppresses development of atopic dermatitis-like skin lesions

Platycodi Radix has been used to treat chronic diseases, such as bronchitis, asthma, and hyperlipidemia. In this study, we examined the effect of an aqueous extract, Changkil (CK), from the root of Platycodi Radix on 2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis (AD)-like skin lesions. Administration of CK onto DNCB-induced AD-like skin lesions in NC/Nga mice ameliorated lesion intensity scores, levels of IgE, thymus and activation-regulated chemokine (TARC), TNF-α, and IL-4 in serum and ears. In contrast, CK increased level of the immunosuppressive cytokine IL-10. Histopathological examination showed reduced thickness of the epidermis/dermis and dermal infiltration of inflammatory cells in the ears. CK also suppressed TNF-α/IFN-γ-induced mRNA expression and production of TARC in HaCaT cells. CK exerts beneficial effects on AD symptoms, suggesting that CK is an effective potential therapeutic agent for AD.     

Psidium guajava extract inhibits thymus and activation-regulated chemokine (TARC/CCL17) production in human keratinocytes by inducing heme oxygenase-1 and blocking NF-κB and STAT1 activation

Psidium guajava (P. guajava) is a food and medicinal plant with antioxidant, anti-inflammatory, and anti-allergic activities that support its traditional uses. The aim of this study was to determine the effects of P. guajava ethyl acetate extract (PGEA) on atopic dermatitis and to investigate the possible mechanisms by which PGEA inhibits cytokine-induced Th2 chemokine expression in HaCaT human keratinocyte cells. We found that PGEA suppressed the IFN-γ/TNF-α-co-induced production of thymus and activation-regulated chemokine (TARC) protein and mRNA in HaCaT cells. Additionally, PGEA inhibited the TNF-α/IFN-γ-co-induced activation of NF-κB and STAT1 and increased the expression of heme oxygenase-1 (HO-1) protein and mRNA. HO-1 inhibitor enhanced the suppressive effects of PGEA on TNF-α/IFN-γ-co-induced TARC production and gene expression. Collectively, these data demonstrate that PGEA inhibits chemokine expression in keratinocytes by inducing HO-1 expression and it suggests a possible therapeutic application in atopic dermatitis and other inflammatory skin diseases.     

Xanthone suppresses allergic contact dermatitis in vitro and in vivo

Xanthone is a phenolic compound found in a few higher plant families; it has a variety of biological activities, including antioxidant, anti-inflammatory, and anticancer properties. However, the molecular and cellular mechanisms underlying the activity of xanthone in allergic contact dermatitis (ACD) remain to be explored. Therefore, this study aimed to investigate the regulatory effects of xanthone in ACD in human keratinocytes (HaCaT cell), and human mast cell line (HMC-1 cell) in vitro and in an experimental murine model. The results demonstrated that treatment with xanthone reduced the production of pro-inflammatory cytokines and chemokines including interleukin (IL)-1β, IL-6, IL-8, and expression of chemokines thymus and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC) in tumor necrosis factor (TNF)-α and interferon (IFN)-γ-stimulated HaCaT cells. Xanthone also suppressed the production of pro-inflammatory cytokines, chemokines, and allergic mediators in phorbol myristate acetate/A23187 calcium ionophore (PMACI)-stimulated HMC-1 cells. Xanthone significantly suppressed the phosphorylation of mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) and activation of caspase-1 signaling pathway in vitro model. Additionally, xanthone administration alleviated 2,4-dinitrofluorobenzene (DNFB)-induced atopic dermatitis like-skin lesion by reducing the serum levels of immunoglobulin E (IgE), histamine, and pro-inflammatory cytokines and suppressing MAPKs phosphorylation. Xanthone administration also inhibited mortality due to compound 48/80-induced anaphylactic shock and suppressed the passive cutaneous anaphylaxis (PCA) reaction mediated by IgE. Collectively, these results suggest that xanthone has a potential for use in the treatment of allergic inflammatory diseases.     

Anti-Inflammatory Effect of Quercetagetin,an Active Component of Immature Citrus unshiu,in HaCaT Human Keratinocytes

Citrus fruit contain various flavonoids that have multiple biological activities. However, the content of these flavonoids are changed during maturation and immature Citrus is known to contain larger amounts than mature. Chemokines are significant mediators for cell migration, while thymus and activation-regulated chemokine (TARC/CCL17) and macrophage-derived chemokine (MDC/CCL22) are well known as the typical inflammatory chemokines in atopic dermatitis (AD), a pruritic and chronic inflammatory skin disease. We reported recently that the EtOH extract of immature Citrus unshiu inhibits TARC and MDC production. Therefore, we investigated the activity of flavonoids contained in immature Citrus on TARC and MDC levels. As a result, among the various flavonoids, quercetagetin has stronger inhibitory effects on the protein and mRNA expression of TARC and MDC than other flavonoids. Quercetagetin particularly has better activity on TARC and MDC level than quercetin. In HPLC analysis, the standard peak of quercetagetin matches the peaks of extract of immature C. unshiu. This suggests that quercetagetin is an anti-inflammatory component in immature C. unshiu.     

Pulmonary exposure to diesel exhaust particles induces airway inflammation and cytokine expression in NC/Nga mice

Although several studies have reported that diesel exhaust particles (DEP) affect cardiorespiratory health in animals and humans, the effect of DEP on animal models with spontaneous allergic disorders has been far less intensively studied. The Nc/Nga mouse is known to be a typical animal model for human atopic dermatitis (AD). In the present study, we investigated the effects of repeated pulmonary exposure to DEP on airway inflammation and cytokine expression in NC/Nga mice. The animals were randomized into two experimental groups that received vehicle or DEP by intratracheal instillation weekly for six weeks. Cellular profiles of bronchoalveolar lavage (BAL) fluid and expressions of cytokines and chemokines in both the BAL fluid and lung tissues were evaluated 24 h after the last instillation. The DEP challenge produced an increase in the numbers of total cells, neutrophils, and mononuclear cells in BAL fluid as compared to the vehicle challenge (P<0.01). DEP exposure significantly induced the lung expressions of interleukin (IL)-4, keratinocyte chemoattractant (KC), and macrophage inflammatory protein (MIP)-1 when compared to the vehicle challenge. These results indicate that intratracheal exposure to DEP induces the recruitment of inflammatory cells, at least partially, through the local expression of IL-4 and chemokines in NC/Nga mice.     

Inhibitory effect of Psidium guajava water extract in the development of 2,4-dinitrochlorobenzene-induced atopic dermatitis in NC/Nga mice

Atopic dermatitis (AD) is a chronic, relapsing, and inflammatory skin disease associated with eczematous symptoms and IgE hyperproduction. Psidium guajava is an important food crop and medicinal plant with anti-oxidant, anti-inflammatory, and anti-allergic activities, supporting its traditional uses. Our previous studies have shown that P. guajava extract inhibits Th2 chemokine expression by suppressing the activation of NF-κB and STAT1 co-stimulated with TNF-α and INF-γ. In this study, we investigated the inhibitory effect of P. guajava water extract (PGW) on 2,4-dinitrochlorobenzene (DNCB)-induced AD-like skin lesions in NC/Nga mice. Treatment of cream containing PGW onto DNCB-induced AD-like skin lesions in NC/Nga mice ameliorated lesion intensity scores, levels of IgE, thymus and activation-regulated chemokine (TARC), TNF-α, and IL-4 in serum and ears. In contrast, PGW increased level of the immunosuppressive cytokine IL-10. Histological analyses demonstrated decreased thickening of the epidermis/dermis as well as dermal infiltration by inflammatory cells. These results suggest that cream containing PGW may be a potential therapeutic modality for AD and adjunctive agent to control pruritus in AD.     

The Leaves of Broussonetia kazinoki Siebold Inhibit Atopic Dermatitis-Like Response on Mite Allergen-Treated Nc/Nga Mice

Broussonetia kazinoki Siebold. (B. kazinoki) has long been used in the manufacture of paper in Asian countries. Although B. kazinoki leaves (BK) have been employed in dermatological therapy, use of BK has not been tested in patients with atopic dermatitis (AD). Using Nc/Nga mice, which are genetically predisposed to develop AD-like skin lesions, we confirmed the efficacy of BK in AD treatment. BK extract was applied topically to Dermatophagoides farinae-induced AD-like lesions in Nc/Nga mice, and the effects were assessed both clinically and by measuring skin thickness on the back and ears. We measured the effects of BK extract on plasma levels of IgE and IL-4. We also measured the ability of BK extract to inhibit the secretion of hTARC in HaCaT cells after stimulation by TNF-α and IFN-γ. We found that BK extract significantly reduced ear and dorsal skin thickness and the clinical signs of AD, as well as significantly down-regulating the plasma levels of IgE and IL-4 (p<0.01 for each comparison). Moreover, 500 μg/mL of BK extract inhibited hTARC secretion in HaCaT cells by activated TNF-α/IFN-γ by about 87%. These findings suggest that topical application of BK extract has excellent potential in the treatment of AD.     

Luffa cylindrica suppresses development of Dermatophagoides farinae-induced atopic dermatitis-like skin lesions in Nc/Nga mice

Abstract

Context: The fruit pulp of Luffa cylindrica Roemer (Cucurbitaceae) (LC) has been used to induce hemostasis, resolve phlegm and clear fever in traditional Korean medicine. However, the efficacy of LC has not been examined in atopic dermatitis (AD).

Objective: A 70% ethanol extract of LC was evaluated to determine anti-inflammation and anti-AD effects in vitro and in vivo.

Materials and methods: The inhibitory effects of LC on the production of PGE₂ and histamine were respectively measured in lipopolysaccharide-treated (1?μg/mL) RAW264.7 macrophages and phorbol-12 myristate 13-acetate (50?nM) and A23187 (1?µM)-stimulated HMC-1 mast cells. The production of AD-related chemokines (RANTES, TARC, and MDC) were evaluated in IFN-γ and TNF-α-stimulated (10?ng/mL, each) HaCaT keratinocytes. LC (10?mg/mouse/d) was topically applied to the dorsal skin and ears of Dermatophagoides farina (Pyroglyphidae)-sensitized Nc/Nga mice for 4?weeks.

Results: The IC₅₀ values of LC on PGE₂ and histamine production were 16.89 and 139.9?μg/mL, individually. The production of TARC and RANTES were inhibited 20% and 12% by LC (50?μg/mL) in HaCaT cells, respectively (p?<?0.05). In sensitized-NC/Nga mice, the plasma levels of IgE and histamine were suppressed 36% and 41% by LC, respectively (p?<?0.05). LC also reduced hemorrhage, hypertrophy, and hyperkeratosis of the epidermis and infiltration of mast cells in the dorsal skin and ear.

Discussion and conclusion: LC can inhibit AD-like skin lesions and reduce the generation of IgE via inhibition of the inflammatory responses. LC has potential as a therapeutic agent to treat allergic diseases, including AD.     

Platycodon grandiflorus alleviates DNCB-induced atopy-like dermatitis in NC/Nga mice

Objective:

To investigate the therapeutic effect of crude extract from Platycodon grandiflorum (PG) roots on atopic dermatitis (AD)-like skin lesions in NC/Nga mice.

Materials and Methods:

To develop atopic dermatitis-like lesions, 200 μl of 0.3% 1-chloro-2, 4-dinitro benzene (DNCB) in acetone/olive oil (3:1) was applied 3 times a week for 2 weeks on the shaved skin of their backs. PG extract was dissolved in saline and orally administrated at concentrations of 300 and 500 mg/kg every day for 2 weeks. The therapeutic effect of PG on AD-like skin lesions was assessed by measuring skin severity scores and epithermal thickness, serum total immunoglobulin (Ig) E, histopathological findings for inflammatory cells including mast cells, macrophage and T cells, and mRNA expression of various cytokines related to the inflammatory and allergic response. The significance of inter-group differences was analyzed using the ANOVA test. Data were considered to be significant when P < 0.05 or P < 0.01.

Results:

Oral treatment of PG suppressed AD-like skin lesions according to the assessment of skin severity and epithermal thickness in the DNCB-treated NC/Nga mice. This alleviation was further correlated with a reduction of elevated serum total IgE or cytokine mRNA in the PG-treated group compared with vehicle-treated positive group. In addition, infiltrated inflammatory cells decreased on the skin lesions compared with vehicle-treated group.

Conclusion:

These results suggest that PG may have a potential therapeutic effect for AD via the inhibition of both inflammatory and allergic reaction.KEY WORDS: Allergic reaction, atopic dermatitis, inflammation, Platycodon grandiflorumm     

CC Chemokine Receptor 4 as a Possible Target for Therapy of Atopic Dermatitis

The CC chemokine receptor CCR4 is selectively expressed on Th2-type CD4(+) T cells. Therefore, its ligands, thymus and activation-regulated chemokine (TARC) and macrophage-derived chemokine, can facilitate the recruitment, activation and development of Th2 polarized cells. The allergic inflammation of atopic dermatitis is characterized by a predominance of Th2-type cells. Some reports suggest that CCR4 and TARC are important for the pathogenesis of atopic dermatitis. The future aspects of atopic dermatitis therapy that specifically targets CCR4 are discussed. (c) 2002 Prous Science. All rights reserved.     

Impact on Inflammation and Recovery of Skin Barrier by Nordihydroguaiaretic Acid as a Protease-Activated Receptor 2 Antagonist

Atopic dermatitis is a chronic, inflammatory disease of the skin with increased transepidermal water loss. Both an abnormal inflammatory response and a defective skin barrier are known to be involved in the pathogenesis of atopic dermatitis. Protease activated receptor 2 (PAR2) belongs to a family of G-protein coupled receptors and is activated by both trypsin and a specific agonist peptide, SLIGKV-NH₂. PAR2 is expressed in suprabasal layers of the epidermis and regulates inflammatory responses and barrier homeostasis. In this study, we show that nordihydroguaiaretic acid (NDGA) inhibits the PAR2-mediated signal pathway and plays a role in skin barrier recovery in atopic dermatitis. Specifically, NDGA reduces the mobilization of intracellular Ca²⁺ in HaCaT keratinocytes by down-regulating inflammatory mediators, such as interleukin-8, thymus and activation-regulated chemokine and intercellular cell adhesion molecule-1 in HaCaT keratinocytes. Also, NDGA decreases the protein expression of involucrin, a differentiation maker of keratinocyte, in both HaCaT keratinocytes and normal human epidermal keratinocytes. We examined NDGA-recovered skin barrier in atopic dermatitis by using an oxazolone-induced atopic dermatitis model in hairless mice. Topical application of NDGA produced an increase in transepidermal water loss recovery and a decrease in serum IgE level, without weight loss. Accordingly, we suggest that NDGA acts as a PAR2 antagonist and may be a possible therapeutic agent for atopic dermatitis.     

Topical application of aloperine improves 2,4-dinitrofluorobenzene-induced atopic dermatitis-like skin lesions in NC/Nga mice

Aloperine has been shown to inhibit 2,4-dinitrofluorobenzene (DNFB) induced allergic contact dermatitis in BALB/c mice. In the present study, we further investigated the effect of aloperine on DNFB-induced atopic dermatitis-like skin lesions in NC/Nga mice. NC/Nga mice elicited atopic dermatitis-like skin lesions after the topical application of DNFB. Aloperine treatment significantly inhibited dermatitis index and ear thickness in DNFB-treated NC/Nga mice in a dose-dependent manner. Eosinophils, mast cells infiltration into the ears and plasma level of immunoglobulin (Ig) E were also suppressed by aloperine treatment. Finally, cytokine (interleukin (IL)-1β, IL-4, IL-6, IL-10, IL-13, tumor necrosis factor (TNF)-α and interferon (IFN)-γ) productions in ear biopsies homogenates were significantly elevated after DNFB challenge. Topical application of aloperine increased the immunosuppressive cytokine IL-10 level, while it reduced other cytokines production in a dose-dependent manner. Taken together, these data suggest that aloperine may be one of the effective therapeutic agents for the treatment of atopic dermatitis.     

Establishment of allergic dermatitis in NC/Nga mice as a model for severe atopic dermatitis

Mite antigen has been suggested to play important roles in the onset and/or development of atopic dermatitis, and mite antigen-induced dermatitis models appear beneficial for the basic study of atopic dermatitis. In the present study therefore, we attempted to establish an allergic dermatitis model in mice using Dermatophagoides farinae crude extract as an antigen. Mite antigen solution at a concentration of 1 or 10 mg/ml was painted 5 times repeatedly at an interval of 7 d onto the ear of NC/Nga or BALB/c mice with or without simultaneous tape-stripping. Apparent biphasic ear swelling was observed after the 4th and 5th antigen applications in both strains of mice treated with 10 mg/ml of antigen solution. Thickening of the epidermis, fibrosis of the dermis, and the accumulation of inflammatory cells were also observed after the 5th application. The inflammatory changes were more evident in NC/Nga mice than in BALB/c mice and potentiated by tape-stripping. The ear swelling was accompanied by increased serum IgE, increased expression of interleukin-4 mRNA and decreased expression of interferon-gamma mRNA in cervical lymph nodes and ears. These results indicate that ear swelling caused by repeated mite antigen application with simultaneous tape-stripping has a Th2-dominant background and that the inflammatory responses are expressed more potently in NC/Nga mice than in BALB/c mice. The dermatitis caused by mite antigen in NC/Nga mice appears to be a useful model for the basic study of atopic dermatitis.     

Mechanism underlying the effect of combined therapy using glucosamine and low-dose cyclosporine A on the development of atopic dermatitis-like skin lesions in NC/Nga mice

Combination therapy is often used in the treatment of atopic dermatitis (AD) to improve clinical efficacy or to spare the dose of each drug. Cyclosporine A (CsA) is a calcineurin inhibitor that was developed for the treatment of AD. Glucosamine (Glu) is a potent immunosuppressant that inhibits Th2-mediated immunity. We previously reported that Glu has an ameliorative effect on the development of the pathology in NC/Nga mice. The aims of our study were to investigate the therapeutic efficacy of combination of Glu and low-dose CsA in dermatophagoides farina (Df)-induced AD-like skin lesions in NC/Nga mice and to determine the underlying therapeutic mechanisms. The Df-induced NC/Nga mice with a clinical score of 7 were used for treatment with Glu (500 mg/kg) alone, low-dose CsA (2, 5, and 10 mg/kg) or in combination. The clinical scores were reduced significantly by the combination treatment with Glu and low-dose CsA. The suppression of dermatitis by combined therapy was accompanied by decrease in the plasma level of IgE and in the splenic level of IL-4, IL-5, IL-13, TARC and eotaxin. Histological analysis of the skin also revealed that combination treatment significantly reduced the inflammatory cellular infiltrate, including mast cells and eosinophils. Particularly, immunological evaluation reveals an increase of CD4⁺CD25⁺ Treg cells in the combined treatment. The induction of TSLP, which leads to systemic Th2 response, was reduced in the skin on combination treatment. The protein expression of filaggrin and involucrin was recovered by combination treatment in the skin lesions, whereas the protein expression of keratin-10 and keratin-14 decreased in the combination treatment. Collectively, our findings suggest that combination treatment of Glu and low-dose CsA leads to the therapeutic effects in Df-induced AD-like skin lesion in NC/Nga mice through inhibition of IgE, inflammatory cellular infiltrate, and recovery of skin barrier function via a mechanism that may inhibition of Th2-mediated immune responses, in part, increment of CD4⁺CD25⁺ Treg cells. These results suggest that this combined immunosuppressive treatment may provide important implications for the design of therapeutic strategies aimed at AD treatment.