Induction of atopic eczema/dermatitis syndrome-like skin lesions by repeated topical application of a crude extract of Dermatophagoides pteronyssinus in NC/Nga mice

Interactions between skin-resident dendritic and Langerhans cells and pain-sensing neurons

Various immune cells in the skin contribute to its function as a first line of defense against infection and disease, and the skin's dense innervation by pain-sensing sensory neurons protects the host against injury or damage signals. Dendritic cells (DCs) are a heterogeneous population of cells that link the innate immune response to the adaptive response by capturing, processing, and presenting antigens to promote T-cell differentiation and activation. DCs are abundant across peripheral tissues, including the skin, where they are found in the dermis and epidermis. Langerhans cells (LCs) are a DC subset located only in the epidermis; both populations of cells can migrate to lymph nodes to contribute to broad immune responses. Dermal DCs and LCs are found in close apposition with sensory nerve fibers in the skin and express neurotransmitter receptors, allowing them to communicate directly with the peripheral nervous system. Thus, neuroimmune signaling between DCs and/or LCs and sensory neurons can modulate physiologic and pathophysiologic pathways, including immune cell regulation, host defense, allergic response, homeostasis, and wound repair. Here, we summarize the latest discoveries on DC- and LC-neuron interaction with neurons while providing an overview of gaps and areas not previously explored. Understanding the interactions between these 2 defence systems may provide key insight into developing therapeutic targets for treating diseases such as psoriasis, neuropathic pain, and lupus.

Immunomodulation and mechanisms of fucoidan from Cladosiphon okamuranus ameliorates atopic dermatitis symptoms

Atopic dermatitis (AD) is a long-term allergic skin disorder that occurs most frequently in children. Currently, the common treatment of AD is corticosteroids; however, the drugs cause serious side effects. Therefore, there are many patients who seek complementary and alternative treatments such as healthy food. We report that fucoidan from Cladosiphon okamuranus (COP) exhibit exceptional immuno-modulatory effects significantly improving atopic dermatitis (AD) at both in vitro and in vivo levels: First, we performed the P815 cell degranulation assay, of which the results revealed that COP possesses anti-degranulation activity suggesting COP is very conducive to relieving allergic reactions of AD. Next, we performed the animal model examination, of which AD was significantly improved, suggesting COP can focally and globally modulate the immune systems of animals. The systemic improvements were manifested clearly by decreased epidermal hyperplasia, reduced infiltration of eosinophils, and decreased expression of AD-associated cytokines. Notably, COP reduced epidermal hyperplasia by downregulating the expression of IL-22. COP displayed therapeutic effects, which is comparable to corticosteroids but lack corticosteroid side effects, such as weight loss in our animal study. COP is multitudinous immunomodulatory abilities to serve as a healthy food supplement at the current stage, not least beneficial to atopic dermatitis.

Beneficial effects of ROCEN (Topical Nano-arthrocen) on atopic dermatitis in mice

Objective

Atopic dermatitis (AD) is a chronic inflammatory skin disease mainly caused by immune stimuli. The current study was conducted to investigate the effects of ROCEN and to compare it with betamethasone (Beta) on mice subjected to AD.

Methods

First, the safety of topical ROCEN was tested to determine possible sensitization induction in vivo. Then, the mice were subjected to oxazolone (Oxa) to induce chronic AD. Consequently, they underwent treatment with ROCEN and Beta. Scratching and wiping behaviors related to dermatitis were evaluated in treated animals for 35 days. The histopathology and immunohistochemistry (IHC) analysis of interleukin-8 (IL-8) and tumor necrosis factor-α (TNF-α) cytokines were performed on the dorsal skin of the treated mice.

Results

Topical administration of ROCEN and Beta to the dorsum of sensitized mice for 5 weeks significantly alleviated scratching and wiping symptoms and reduced erythema, scaling, and edema in the skin of the mice with AD. Moreover, histological indices showed that ROCEN effectively reduced leucocyte infiltration and improved skin healing parameters in treated AD mice. Application of ROCEN or Beta reduced IHC markers including IL-8 and TNF-α significantly.

Conclusion

ROCEN alleviated the AD symptoms similar to betamethasone in an experimental animal model.

Allergen-specific immunotherapy induces regulatory T cells in an atopic dermatitis mouse model

BACKGROUND

Several studies have demonstrated that allergen-specific immunotherapy (SIT) can be an effective treatment for atopic dermatitis (AD). However, there is no relevant mouse model to investigate the mechanism and validate the novel modality of SIT in AD.

METHODS

NC/Nga mice with induced AD-like skin lesions received a subcutaneous injection of SIT (an extract of the house dust mite Dermatophagoides farinae [DfE]) or placebo for 5 weeks). Clinical and histological improvements of AD-like skin lesions were examined. The responses of local and systemic regulatory T (Treg) cells, natural killer (NK) cells, B cells, serum immunoglobulin, and T-cell cytokine response to DfE were evaluated to determine the underlying mechanism of the observed results.

RESULTS

Specific immunotherapy significantly improved AD-like skin lesions. Histologically, SIT decreased epidermal thickness and reduced inflammatory cell infiltration, especially that of eosinophils. Concomitantly, SIT suppressed Th2 responses and induced local infiltration of Treg cells into the skin. Also, SIT induced the immunoglobulin G4 and attenuated allergen-specific immunoglobulin E. Furthermore, SIT induced local and systemic IL-10-producing Treg cells and regulatory NK cells.

CONCLUSION

We established a SIT model on AD mice and showed that our model correlates well with previous reports about SIT-treated patients. Also, we revealed NK cells as another possible resource of IL-10 in SIT. Based on our results, we suggest our SIT model as a useful tool to investigate mechanism of action of SIT and to validate the efficacy of new SIT modalities for the treatment of AD.

Dimerized Translationally Controlled Tumor Protein-Binding Peptide Ameliorates Atopic Dermatitis in NC/Nga Mice

Our previous study showed that dimerized translationally controlled tumor protein (dTCTP) plays a role in the pathogenesis of allergic diseases, such as asthma and allergic rhinitis. A 7-mer peptide, called dTCTP-binding peptide 2 (dTBP2), binds to dTCTP and inhibits its cytokine-like effects. We therefore examined the protective effects of dTBP2 in house dust mite-induced atopic dermatitis (AD)-like skin lesions in Nishiki-nezumi Cinnamon/Nagoya (NC/Nga) mice. We found that topical administration of dTBP2 significantly reduced the AD-like skin lesions formation and mast cell infiltration in NC/Nga mice, similarly to the response seen in the Protopic (tacrolimus)-treated group. Treatment with dTBP2 also decreased the serum levels of IgE and reduced IL-17A content in skin lesions and inhibited the expression of mRNAs of interleukin IL-4, IL-5, IL-6, IL-13, macrophage-derived chemokine (MDC), thymus and activation-regulated chemokine (TARC) and thymic stromal lymphopoietin (TSLP). These findings indicate that dTBP2 not only inhibits the release of Th2 cytokine but also suppresses the production of proinflammatory cytokines in AD-like skin lesions in NC/Nga mice, by inhibiting TCTP dimer, in allergic responses. Therefore, dTCTP is a therapeutic target for AD and dTBP2 appears to have a potential role in the treatment of AD.

Estimation of the environmental effect of natural volatile organic compounds from Chamaecyparis obtusa and their effect on atopic dermatitis-like skin lesions in mice

Aromatherapy has been suggested as an alternative therapeutic method for the treatment of atopic dermatitis (AD), eczema and other skin diseases. In the current study, the anti-atopic properties of the volatile organic compounds of Chamaecyparis obtusa (VOCCo) were examined to determine whether they are amenable for use as a pharmaceutical candidate. The alterations in histological features, serum IgE levels and mast cell infiltration following exposure to VOCCo were determined in a 2,4-dinitrochlorobenzene (DNCB)-induced AD-like mouse model. The results of these experiments demonstrated that VOCCo inhibited the development of AD-like skin lesions by reducing the serum IgE level and mast cell infiltration into the dermal and subcutaneous layers. This was supported by screening of immune cytokine mRNAs, including interleukin (IL)-1β and IL-6 from the skin of DNCB-treated mice. The expression of IL-1β and IL-6 in the skin lesions of mice was dose-dependently inhibited by treatment with VOCCo. Furthermore, treatment with VOCCo resulted in the recovery of histopathological features in AD-like skin lesions. These results suggest that VOCCo may have therapeutic and preventive effects for the development of AD.

Genuine traditional Korean medicine, Naju Jjok (Chung-Dae, Polygonum tinctorium) improves 2,4-dinitrofluorobenzene-induced atopic dermatitis-like lesional skin

PURPOSE

Naju Jjok (NJJ, Polygonum tinctorium) is a clear heat and release toxin medicinal. It has been used to treat various inflammatory diseases and as a dye in clothing in traditional Korean medicine. However, the effect of NJJ on atopic dermatitis (AD) has not been elucidated. Therefore, we examined whether NJJ would have an inhibitory effect on AD using the mimic AD murine model and in vitro model.

METHODS

We treated NJJ on 2,4-dinitrofluorobenzene (DNFB)-induced AD-like skin lesions in NC/Nga mice, phorbol myristate acetate/calcium ionophore A23187-stimulated human mast cell line (HMC-1) cells, and anti-CD3/anti-CD28-stimulated splenocytes. Histological analysis, ELISA, PCR, and Western blot analysis were performed.

RESULTS

The oral administration with NJJ suppressed the total clinical severity in DNFB-induced AD-like lesional skin. NJJ significantly suppressed the levels of inflammatory mRNA and protein in AD-like lesional skin. NJJ significantly suppressed the levels of IgE and interleukin-4 in the serum of DNFB-induced AD mice. The expression of mast cells-derived caspase-1 was suppressed by NJJ in AD-like lesional skin. In addition, topical application with NJJ improved clinical symptoms in DNFB-induced AD mice. The topical application with NJJ significantly suppressed the levels of IgE and histamine in the serum of DNFB-induced AD mice. NJJ suppressed the production and mRNA expression of TSLP by blockade of caspase-1 signal pathway in the activated HMC-1 cells. Furthermore, NJJ significantly decreased the production of tumor necrosis factor-α from the stimulated splenocytes.

CONCLUSIONS

In conclusion, these results propose curative potential of natural dye, NJJ by showing the scientific evidence on anti-AD effect of NJJ which has been used traditionally.

Inhibitory effects of Drynaria fortunei extract on house dust mite antigen-induced atopic dermatitis in NC/Nga mice

ETHNOPHARMACOLOGICAL RELEVANCE

Drynaria fortunei (Kunze) J. Sm has been widely used in traditional medicine for the treatment of inflammation, hyperlipidemia, arteriosclerosis, rheumatism, and bone healing. We investigated the anti-inflammatory effects of a 70% ethanol extract of Drynaria fortunei (DFE).

MATERIALS AND METHODS

We evaluated the anti-inflammatory effects of topically applied DFE on house dust mite Dermatophargoides farinae-induced atopic dermatitis-like skin lesions in NC/Nga mice.

RESULTS

Treatment of NC/Nga mice with DFE reduced the dermatitis score, ear thickness, and serum levels of IgE, IgG1, and IL-6. Histopathological analyses of ear and skin lesions showed inhibition of the thickening of the epidermis and reduced epidermal/dermal infiltration of inflammatory cells. In ear lesions, mRNA expression levels of IL-4, IL-6, and tumor necrosis factor-α were reduced by DFE treatment.

CONCLUSIONS

DFE inhibited the development of dermatitis-like skin lesions in NC/Nga mice. These results suggest that DFE may be a therapeutic candidate for the treatment of AD.

Inhibitory effects of Chelidonium majus extract on atopic dermatitis-like skin lesions in NC/Nga mice

AIM OF THE STUDY

Chelidonium majus (CM) has traditionally been used for treatment of various inflammatory diseases including atopic dermatitis (AD). However its action on atopic dermatitis (AD) is unclear. Therefore, we investigated the effect of CM on AD using NC/Nga mice as an AD model.

MATERIALS AND METHODS

The effect of CM on 1-chloro-2,4-dinitrobenzene (DNCB) induced NC/Nga mice was evaluated by examining skin symptom severity, itching behavior, ear thickness, levels of serum immunoglobulin E (IgE), tumor necrosis factor-α (TNF-α), and interlukin-4 (IL-4), skin histology.

RESULTS

The CM significantly reduced the total clinical severity score, itching behavior, ear thickness and the level of serum IgE in AD mouse model. CM not only decreased TNF-α but also IL-4.

CONCLUSION

These results suggest that CM may be a potential therapeutic modality for AD.

Korean red ginseng extract ameliorates skin lesions in NC/Nga mice: an atopic dermatitis model

AIM OF THE STUDY

Korean red ginseng (KRG, Panax ginseng C.A. Meyer) has traditionally been considered to harbor anti-allergic effects, however its action on atopic dermatitis (AD) is unclear. Therefore, we investigated the effect of KRG on AD using NC/Nga mice as an AD model. In addition, we examined the effect of aprepitant (substance P specific neurokinin receptor antagonist) on AD.

MATERIALS AND METHODS

The KRG extract and aprepitant were administered orally to NC/Nga mice. The efficacy of KRG and aprepitant was evaluated by assessing total clinical severity score, ear thickness, serum IgE level and histology. In addition, mRNA and protein expression were measured by real-time RT-PCR and immunohistochemistry, respectively.

RESULTS

The KRG extract significantly reduced the total clinical severity score, ear thickness and the level of serum IgE in AD mouse model, whereas aprepitant reduced only the serum IgE level. KRG not only decreased TNF-α, IFN-γ and substance P but also reduced the infiltration of FOXP3+ regulatory T (Treg) cells and CD1a+ Langerhans cells in the lesions, whereas aprepitant decreased only substance P and the infiltration of Treg cells.

CONCLUSION

These results suggest that KRG extract may be a potential therapeutic modality for AD and aprepitant could be used as adjunctive agent to control pruritus in AD.

Oral administration of ginsenoside Rh1 inhibits the development of atopic dermatitis-like skin lesions induced by oxazolone in hairless mice

In the present study, we examined the inhibitive effect of ginsenoside Rh1 on oxazolone-induced atopic dermatitis-like skin lesions in hairless mice. Oral administration of ginsenoside Rh1 improved clinical symptoms, and it was confirmed by histophathological analysis. In ginsenoside Rh1 (20mg/kg) group, ear swellings and ear weights were significantly lower than the control group. Moreover, elevation of IL-6 and total IgE levels in serum were suppressed by ginsenoside Rh1 (20mg/kg). In addition, ginsenoside Rh1 (20mg/kg) significantly increased mRNA expression of IFNγ and Foxp3, and slightly decreased IL-4 expression in draining lymph nodes. The results suggest that ginsenoside Rh1 can alleviate inflammatory symptoms in atopic dermatitis (AD) by reduction of IgE and IL-6 levels in peripheral blood, increase of Foxp3 expression in draining lymph nodes and suppression of inflammation in skin regions. Indeed, ginsenoside Rh1 exhibited therapeutic possibility in immune disorders.

Effect of pedunculagin investigated by non-invasive evaluation on atopic-like dermatitis in NC/Nga mice

BACKGROUND/PURPOSE

Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disorder that is becoming increasingly prevalent. Experimental animal models have been an indispensable tool for studying its pathological mechanisms and for in vivo testing of novel therapeutic approaches. AD-like lesions can be induced experimentally in NC/Nga mice. Pedunculagin, an ellagitannin purified from the Manchurian alder, Alnus hirsuta var. microphylla, Betulaceae, is a novel immunomodulator. To evaluate the effect of pedunculagin for AD-like lesions in NC/Nga mice, using clinical and non-invasive methods.

METHODS

AD-like lesions were induced in NC/Nga mice using 2,4,6-trinitrochlorobenzene (TNCB). A cream containing 0.1% or 0.5% pedunculagin was applied to the positive treatment group, and the base cream without pedunculagin was applied to the negative treatment group. The control group did not receive any kind of topical agents. We evaluated the therapeutic efficacy of pedunculagin for AD by statistical evaluation of the clinical severity score using non-invasive biomedical engineering tools before treatment, and 1 day, 3 days, 1 week, 2 weeks and 4 weeks afterwards.

RESULTS

An AD-like skin rash was successfully induced using TNCB in NC/Nga mice. The group receiving higher concentrations of pedunculagin showed faster and greater improvement.

CONCLUSION

Our results suggest that remedies made from natural materials like pedunculagin are now showing promise for medical applications, and many new studies are expected to explore this potential.

Therapeutic effects of Baicalein on atopic dermatitis-like skin lesions of NC/Nga mice induced by dermatophagoides pteronyssinus

The present study was conducted to investigate the effects of Baicalein (BE), which is hydrolyzed product of Baicalin (BA), on atopic dermatitis (AD). AD was induced in NC/Nga mice by DPE treatment. BE hydrogels treatment reduced the levels of skin severity scores. BE hydrogels treatment also decreased inflammatory cytokines such as TNF-alpha, IL-6, and its level in the serum. BE hydrogels treatment elevated IFN-gamma level in the spleenocyte culture supernatant. Cell numbers in the skin positive to CD3+/CD69+, CCR3+, CD11b+/Gr-1+, B220+/IgE+ all of which were up-regulated in AD-induced mice were decreased and returned to normal levels. Histological examination showed that infiltration levels of immune cells in the skin of AD-induced NC/Nga mice were much improved by BE hydrogels treatment. These results thus suggest that BE can regulate molecular mediators and immune cells that are functionally associated with atopic dermatitis induced in NC/Nga mice, and may play an important role in recovering AD symptoms.

Flaky tail mouse denotes human atopic dermatitis in the steady state and by topical application with Dermatophagoides pteronyssinus extract

The barrier abnormality, a loss-of-function mutation in the gene encoding filaggrin (FLG), which is linked to the incidence of atopic dermatitis (AD), is a recently discovered but important factor in the pathogenesis of AD. Flaky tail (Flg(ft)) mice, essentially deficient in filaggrin, have been used to investigate the role of filaggrin on AD. However, the relevancy of Flg(ft) mice to human AD needs to be determined further. In this study, we observed the clinical manifestations of Flg(ft) mice in the steady state and their cutaneous immune responses against external stimuli, favoring human AD. Under specific pathogen-free conditions, the majority of Flg(ft) mice developed clinical and histological eczematous skin lesions similar to human AD with outside-to-inside skin barrier dysfunction evaluated by newly devised methods. In addition, cutaneous hapten-induced contact hypersensitivity as a model of acquired immune response and a mite extract-induced dermatitis model physiologically relevant to a human AD were enhanced in Flg(ft) mice. These results suggest that the Flg(ft) mouse genotype has potential as an animal model of AD corresponding with filaggrin mutation in human AD.

Analysis of MAST-CLA Results as a Diagnostic Tool in Allergic Skin Diseases

BACKGROUND

Urticaria and atopic dermatitis are representative allergic skin diseases that can be mediated by IgE. Measuring levels of specific IgE can be used to confirm causative agents of these skin diseases.

OBJECTIVE

To analyze results from the multiple allergosorbent test chemiluminescent assay (MAST-CLA), which measures specific IgE in the presence of a causative agent/allergen, in IgE-mediated skin diseases.

METHODS

A total of 404 patients with urticaria, atopic dermatitis or pruritus were enrolled in the present study. Positive rates of specific IgE as well as total serum IgE from the MAST-CLA were compared.

RESULTS

Positive rates of specific IgE were highest in atopic dermatitis patients, followed by urticaria, and then pruritus, with 57.0%, 37.1%, and 20.8%, respectively (p<0.05). House dust mite species were the most common allergens in both atopic dermatitis and urticaria skin diseases. There were no differences in the overall MAST-CLA results between acute and chronic urticaria. The relative positive rate of inhalant allergen was significantly higher in adult than in child atopic dermatitis patients.

CONCLUSION

Results from the MAST-CLA showed diversity among the three disease groups, and within each disease group, with different positive rates of specific IgE, a different mean allergen number per patient, and so on. Therefore, we concluded that MAST-CLA could be a useful diagnostic tool for various allergic skin diseases.

Mast cells in atopic dermatitis

Mast cells play as the major effector cells in immediate hypersensitivity through activation via the high-affinity IgE receptor, Fc epsilon RI, although many other functions have recently been discovered for this cell type. Given the broad array of proinflammatory mediators secreted from Fc epsilon RI-activated mast cells, as well as sensitization to allergens, IgE elevation, and increased mast cells in a majority of atopic dermatitis patients, mast cells are believed to be involved in the pathogenesis of atopic dermatitis. Numerous animal models have been used to study this epidemic disease. Here we review the recent progress to synthesize our current understanding of this disease and potential mechanisms for a mast cell's role in the disease.

Does hapten exposure predispose to atopic disease? The hapten-atopy hypothesis

Contact allergy data indicates that atopics have heightened oral tolerance to haptens (chemical allergens). We speculate here, that artificially increased oral exposure to chemicals compete with dietary proteins for the development of oral tolerance, predisposing to the acquisition of food protein allergy and representing one driver for the increasing prevalence of protein allergy and/or atopy. Hapten exposure via other surfaces such as the skin and airways might also be important in promoting atopic disease. Consistent with this hypothesis it is notable that over 40 years, with the huge increase in atopic disease, there has also been an increase in dietary hapten exposure through processed food, formula milk and oral antibiotic and drug use.

Inhibition of skin inflammation and atopic dermatitis by topical application of a novel ceramide derivative, K112PC-5, in mice

PC-9S (N-Ethanol-2-mirystyl-3-oxo-stearamide) is a synthetic ceramide and has been known to be effective in atopic and psoriatic patients. K112PC-5 (2-Acetyl-N-(1,3-dihydroxyisopropyl)-tetradecanamide) is a novel ceramide derivative of PC-9S. In the present study, we examined the effect of K112PC-5 on macrophage and T lymphocyte function in primary macrophages and splenocytes, respectively, as well as the effect of topical application of K112PC-5 on skin inflammation and atopic dermatitis (AD) in mouse models. K112PC-5 inhibited lipopolysaccharide-induced nitrite generation in mouse peritoneal macrophages in a dose-dependent manner. However, K112PC-5 did not affect concanavalin A-induced proliferation, interleukin (IL)-2 secretion and IL-4 secretion in mouse splenocytes. In addition, K112PC-5 significantly suppressed the increase in phorbol ester-induced ear thickness in BALB/c mice. Further study demonstrated that topical application of K112PC-5 also inhibited AD induced by extracts of dust mites, Dermatophagoides pteronyssinus and Dermatophagoides farinae, in NC/Nga mice. Taken together, these results showed that K112PC-5 exerted an anti-inflammatory effect both in vitro and in vivo and proved to be beneficial in an animal model of AD. Our results suggest that K112PC-5 might be beneficial as a topical agent for the treatment of AD.

Inhibition of atopic dermatitis-like skin lesions by topical application of a novel ceramide derivative, K6PC-9p, in NC/Nga mice

Atopic dermatitis (AD) is a chronic inflammatory skin disease that commonly begins in childhood. K6PC-9p (N-(Ethyl dihydrogenphosphate)-2-hexyl-3-oxo-decanamide) is a synthetic ceramide derivative of PC-9S (N-Ethanol-2-mirystyl-3-oxo-staramide), which was known to be effective in atopic patients. In this study, we examined the effect of topical application of K6PC-9p on skin inflammation and AD-like skin lesions in mouse models. K6PC-9p dose-dependently inhibited phorbol ester-induced increase in ear thickness in BALB/c mice. Moreover, topical application of K6PC-9p suppressed dust mite extract-induced AD-like skin lesions in NC/Nga mice. Histopathological analysis revealed that both ear swelling and leucocyte infiltration were suppressed by K6PC-9p treatment. K6PC-9p also suppressed IL-4 and TNF-alpha expression in the ears and mast cell infiltration into the ears in NC/Nga mice. Further study demonstrated that K6PC-9p inhibited ConA-induced IL-4 secretion and LPS-induced macrophage activation. Taken together, our results showed that topical application of K6PC-9p exerts beneficial effects in animal model of skin inflammation and AD, suggesting that K6PC-9p might be a promising topical agent for the treatment of inflammatory skin diseases.

An improved mouse model of atopic dermatitis and suppression of skin lesions by an inhibitor of Tec family kinases

BACKGROUND

Atopic dermatitis is a chronic or chronically relapsing, pruritic inflammatory skin disease. The incidence of atopic dermatitis has dramatically increased during the past three decades in industrialized countries. We attempted to develop an improved method to induce an animal model of atopic dermatitis and to use it to evaluate the efficacy of a Tec family kinase inhibitor.

METHODS

We treated dermatitis-prone inbred mice, NC/Nga, by repetitive epicutaneous applications of a house dust mite allergen and staphylococcal enterotoxin B to induce atopic dermatitis-like skin lesions.

RESULTS

We established a highly efficient protocol to induce skin lesions in NC/Nga mice, which were histologically and immunologically similar to human atopic dermatitis. Similar to human patients, serum IgE levels were increased in dermatitis-induced mice. Consistent with the proposed roles of infiltrated immune cells in the pathogenesis of human atopic dermatitis, skin lesions were treatable with terreic acid, an inhibitor of Tec family kinases, as well as dexamethasone.

CONCLUSIONS

We established a highly efficient, highly reproducible protocol to induce skin lesions in NC/Nga mice and successfully applied it to show the efficacy of terreic acid in treating skin lesions. This mouse model of atopic dermatitis will be useful to study the pathogenetic processes of atopic dermatitis and to evaluate the efficacy of drug candidates.

Characterization of a hapten-induced, murine model with multiple features of atopic dermatitis: structural, immunologic, and biochemical changes following single versus multiple oxazolone challenges

Atopic dermatitis (AD) is a chronic dermatosis bearing clinical, histological, and immunologic similarities to chronic allergic contact dermatitis (ACD). AD shows a Th2 cell-dominant inflammatory infiltrate, elevated serum IgE levels, a permeability barrier abnormality, and Staphylococcus aureus colonization. Repeated hapten challenges reportedly produce a Th2-like hypersensitivity reaction (Th2-like HR). Here, 9-10 challenges with oxazolone (Ox) to hairless mice also produced a chronic Th2-like HR. Permeability barrier function and expression of differentiation proteins, filaggrin, loricrin, and involucrin, became abnormal. CRTH-positive Th2-dominant inflammatory infiltrate, with increased IL-4 expression, and a large increase in serum IgE levels were observed. The barrier abnormality was associated with decreased stratum corneum (SC) ceramide content and impaired lamellar body secretion, resulting in abnormal lamellar membranes, as in human AD. Furthermore, as in human AD, epidermal serine protease activity in SC increased and expression of two lamellar body-derived antimicrobial peptides, CRAMP and mBD3, declined after Ox challenges, paralleling the decrease of their human homologues in AD. Thus, multiple Ox challenges to normal murine skin produce a chronic Th2-like HR, with multiple features of human AD. Because of its reproducibility, predictability, and low cost, this model could prove useful for evaluating both pathogenic mechanisms and potential therapies for AD.