Allergic Contact Dermatitis In Mice Research Articles

Baicalein ameliorates chronic itch in ACD mice by suppressing the spinal astrocytic STAT3-LCN2 cascade.

Chronic itch is a maladaptive and debilitating symptom in patients with allergic contact dermatitis (ACD), adversely affecting their quality of life. There is a lack of effective treatments for ACD-associated uncontrollable itch. In this study, we explored the antipruritic effects of baicalein (BE), a bioactive flavonoid extracted from the root of Scutellaria baicalensis Georgi, and the underlying mechanisms in alleviating chronic itch triggered by diphenylcyclopropenone (DCP) in a mouse model of ACD. The ACD mice were intraperitoneally injected with BE (5, 30, and 60 mg·kg-1·d-1) for 7 days during the DCP challenge phase. The results showed that DCP-treated mice exhibited severe spontaneous scratching behaviors that wasreduced after BE injections in a dose-dependent manner accompanied by inhibition of spinal astrocyte activation. We observed that the spinal astrocytic STAT3-LCN2 cascade plays a crucial role in controlling the activation of astrocytes in chronic itch. Intrathecal injection of the STAT3 inhibitor AG490 or Lcn2 siRNA significantly reduced scratching behavior and astrocyte activation in ACD mice. Moreover, BE markedly attenuated the increased phosphorylation of STAT3 (p-STAT3) and LCN2 expression in the spinal cords of ACD mice and in lipopolysaccharide-stimulated primary spinal astrocytes. Altogether, BE relieved chronic itch by suppressing the spinal astrocytic STAT3-LCN2 cascade. These findings provide a potential avenue for the management of chronic itch. Schematic summary of the main findings illustrating that BE alleviates chronic itch through suppressing the spinal astrocytic STAT3-LCN2 cascade. Specifically, BE suppresses the expression of p-STAT3 to inhibit the reactive state of astrocytes in spinal dorsal horn, and then decreases the expression of astrocytic LCN2 to alleviate chronic itch in ACD mice.

Ferrostatin-1 alleviates skin inflammation and inhibits ferroptosis of neutrophils and CD8+ T cells in allergic contact dermatitis

BackgroundFerroptosis is considered as an immunogenic type of regulated cell death and associated with the pathogenesis of inflammatory skin diseases. However, the involvement and function of ferroptosis in allergic contact dermatitis (ACD) remains unknown. ObjectiveTo explore the role of ferroptosis in ACD. To reveal which type of cells develops ferroptosis in ACD. MethodsWe detected the key markers of ferroptosis in 1-Chloro-2,4-dinitrochlorobenzene (DNCB)-induced ACD mice model. We applicated ferrostatin-1 (Fer-1) to restrain ferroptosis in ACD mice and then compared the severity of dermatitis and the level of inflammation and ferroptosis in dermis and epidermis, respectively. Keratinocyte-specific Gpx4 conditional knockout (cKO) mice were used to investigate the function of keratinocyte ferroptosis in the development of ACD. Single-cell RNA sequencing was conducted to analyze the affection of Fer-1 on different type of cells in ACD. ResultsFerroptosis was involved in DNCB-induced ACD mice. Ferroptosis activation was more remarkable in dermis rather than in epidermis. Gpx4 cKO mice showed similar severity of skin dermatitis as control mice. Fer-1 alleviated skin inflammation in mice and reduced ferroptosis in neutrophils and CD8+ T cells both of which contribute to development of ACD. ConclusionFerroptosis was activated in immune cells, especially neutrophils and CD8+ T cells in DNCB-induced ACD mice. Fer-1 treatment inhibited ferroptosis of neutrophils and CD8+ T cells and relieved skin damage in ACD mice.

Aloe-emodin relieves allergic contact dermatitis pruritus by inhibiting mast cell degranulation

Urushiol-induced allergic contact dermatitis (ACD) is a chronic inflammatory skin disease in which skin barrier dysfunction leads to pruritus and eczematous lesions. ACD is triggered by immune imbalance. Aloe emodin is an anthraquinone derivative extracted from rhubarb, aloe and other traditional Chinese medicines. It has a wide range of pharmacological effects, including anti-inflammatory, anti-tumor, and anti-allergic effects. The purpose of our study was to demonstrate the effectiveness of aloe-emodin on urushiol-induced acute pruritus and allergic contact dermatitis. The results showed that urushiol could stimulate keratinocytes to release chemokines CXCL1, CXCL2, CCL2, TSLP, and TNF-α, which recruit or activate mast cells. Aloe-emodin treatment inhibited inflammatory-response-induced mast cell degranulation in skin lesions and suppressed the expression of inflammatory cytokines, such as interleukin-4, and interleukin-6. Therefore, the results indicate that aloe-emodin can improve urushiol-induced acute pruritus and allergic contact dermatitis in mice by inhibiting mast cell degranulation.

Vascular Endothelial Growth Factor a Promotes Chronic Itch via VEGFA-VEGFR2-PI3K-TRPV1 Axis in Allergic Contact Dermatitis.

Allergic contact dermatitis (ACD), a prevalent skin disorder affecting up to 20% of the population, triggers significant discomfort and health implications. Our research investigates the pivotal role of Vascular Endothelial Growth Factor A (VEGFA) in chronic itching associated with ACD. Bioinformatics methods were utilized to identify differentially expressed genes (DEGs) between ACD models and patients. In vivo models of chronic pruritus in mice induced by 2,4-dinitrofluorobenzene (DNFB) were employed. Mice were administered subcutaneously with a VEGFA inhibitor, sFlt1, and compared to a control group. Real-time RT-PCR, Western blot, and immunohistochemical staining were performed to evaluate VEGFA expression and the impact of sFlt1 on itching behavior. The analysis revealed that VEGFA is significantly upregulated in ACD skin, primarily expressed by keratinocytes. Administration of the VEGFA inhibitor sFlt1 in the ACD mouse model led to a substantial reduction in scratching behavior, indicating that VEGFA may mediate pruritus through the VEGFA-VEGFR2-PI3K-TRPV1 signaling pathway. These findings suggest that VEGFA plays a crucial role in ACD-associated pruritus and may serve as a potential therapeutic target. However, further research is required to validate these findings and to explore additional molecular pathways involved in the pruritic response in ACD.

Xanthotoxol relieves itch in mice via suppressing spinal GRP/GRPR signaling

Although pruritus, commonly known as itch, is a common and debilitating symptom associated with various skin conditions, there is a lack of effective therapies available. Xanthotoxol (XAN), a biologically active linear furocoumarin, shows potential in the treatment of various neurological disorders. In this study, we discovered that administering XAN either through intraperitoneal or intrathecal injections effectively reduced scratching behavior induced by compound 48/80 or chloroquine. Importantly, XAN also substantially alleviates chronic itch in dry skin and allergic contact dermatitis mice. Substantial progress has highlighted the crucial role of gastrin-releasing peptide (GRP)-gastrin-releasing peptide receptor (GRPR) signaling in the dorsal spinal cord in transmitting various types of itch. Our behavior tests revealed that XAN significantly alleviated scratching behaviors induced by intrathecal administration of GRP or GRPR agonist bombesin. Furthermore, XAN reduced the activation of neurons in the spinal cord caused by intrathecal administration of GRP in mice. Moreover, XAN attenuates the activation of spinal GRPR-positive neurons in itchy mice. These findings suggest that XAN mitigates itch in mice by suppressing spinal GRP/GRPR signaling, thereby establishing XAN as a promising therapeutic option for treating pruritus.

CD100 boosts the inflammatory response in the challenge phase of allergic contact dermatitis in mice.

Allergic contact dermatitis (ACD) is an inflammatory disease with a complex pathophysiology in which epidermal-resident memory CD8+ T (TRM ) cells play a key role. The mechanisms involved in the activation of CD8+ TRM cells during allergic flare-up responses are not understood. The expression of CD100 and its ligand Plexin B2 on CD8+ TRM cells and keratinocytes before and after allergen exposure was determined by flow cytometry and RT-qPCR. The role of CD100 in the inflammatory response during the challenge phase of ACD was determined in a model of ACD in CD100 knockout and wild-type mice. We show that CD8+ TRM cells express CD100 during homeostatic conditions and up-regulate it following re-exposure of allergen-experienced skin to the experimental contact allergen 1-fluoro-2,4-dinitrobenzene (DNFB). Furthermore, Plexin B2 is up-regulated on keratinocytes following exposure to some contact allergens. We show that loss of CD100 results in a reduced inflammatory response to DNFB with impaired production of IFNγ, IL-17A, CXCL1, CXCL2, CXCL5, and IL-1β and decreased recruitment of neutrophils to the epidermis. Our study demonstrates that CD100 is expressed on CD8+ TRM cells and is required for full activation of CD8+ TRM cells and the flare-up response of ACD.

TRPA1 is involved in the inhibitory effect of Ke-teng-zi on allergic contact dermatitis via MAPK and JAK/STAT3 signaling pathways.

The seeds of Entada phaseoloides (Linn.) Merr. commonly named "Ke-teng-zi" is a traditional Chinese folk medicine and reported to treat dermatitis, spasm, and headache. However, the exact effect and the mechanism of Ke-teng-zi on the treatment of dermatitis is unclear. To elucidate the antipruritic effect and molecular mechanisms of Ke-teng-zi on the treatment of allergic contact dermatitis (ACD). The main components of the n-butanol fraction of 70% ethanol extract from Ke-teng-zi (abbreviated as KB) were analyzed by HPLC. The chloroquine (CQ)-induced acute itch and squaraine dibutyl ester (SADBE)-induced ACD chronic itch in mice was established, and the TNF-α/IFN-γ stimulated Human keratinocytes (HaCaT) were used to evaluate the antipruritic and anti-inflammatory effects of KB. Behavioral tests, lesion scoring, and histology were also examined. The expression levels of molecules in MAPK and JAK/STAT3 pathways, the mRNA levels of chemokines and cytokines in both the skin of ACD mice and the HaCaT cells were detected by western blot and qPCR. Furthermore, whole-cell patch-clamp recordings in TRPA1-tranfected HEK293T cells were used to elucidate the effect of KB on TRPA1 channels. TRPA1 siRNA was used to evaluate the role of TRPA1 in the anti-inflammatory effect of KB in keratinocytes. The main compounds in KB could bind to the active sites of TRPA1 mainly through hydrogen bond and hydrophobic bond interactions. KB could inhibit the scratching behavior in CQ-induced acute itch, and the inhibitory effect of KB was blocked by TRPA1 inhibitor HC-030031. In addition, KB significantly decreased the scratching bouts of ACD mice, reduced the skin lesion scores, mast cells degranulation, and epidermal thickening, inhibited the production of inflammatory chemokines/cytokines and CGRP, and down-regulated the levels of p-ERK1/2, p-p38, and p-STAT3, compared to the ACD mice. Moreover, continuous application of KB induced the desensitization of TRPA1 channels. Also, KB inhibited the expression of p-ERK1/2, p-p38, and p-STAT3, and down-regulated the expression of inflammatory chemokines and cytokines in vitro, which were reversed by the TRPA1 siRNA. KB alleviated the pruritus and skin inflammation in ACD mice through TRPA1 channels desensitization and down-regulation of intracellular MAPK and JAK/STAT3 signaling pathways. Our results suggested that Ke-teng-zi is a potential drug for the treatment of inflammatory skin diseases such as ACD.

151 Accumulation of T cells with Bach2 expression at a low level could cause a prolonged inflammation of allergic contact dermatitis in mice

151 Accumulation of T cells with Bach2 expression at a low level could cause a prolonged inflammation of allergic contact dermatitis in mice

Pharmacological Profile of Difamilast, a Novel Selective Phosphodiesterase 4 Inhibitor, for Topical Treatment of Atopic Dermatitis.

PDE4 inhibitors are expected to be anti-inflammatory agents based on their mechanism of action, but the application of this drug class is limited by a narrow therapeutic window due to adverse effects associated with gastrointestinal function. Difamilast, a novel selective phosphodiesterase 4 (PDE4) inhibitor, demonstrated significant efficacy without adverse reactions such as nausea and diarrhea in patients with atopic dermatitis (AD) and was recently approved in Japan. In this study, we investigated the pharmacological and pharmacokinetic properties of difamilast to provide nonclinical data to help understand the clinical effects. Difamilast selectively inhibited recombinant human PDE4 activity in assays. The IC50 of difamilast against PDE4B, a PDE4 subtype that plays an important role in the inflammatory response, was 0.0112 μM, representing a 6.6-fold decrease compared with the IC50 against PDE4D (0.0738 μM), a subtype that can trigger emesis. Difamilast inhibited TNF-α production in human (IC50 = 0.0109 μM) and mouse (IC50 = 0.0035 μM) peripheral blood mononuclear cells and improved skin inflammation in a mouse model of chronic allergic contact dermatitis. These effects of difamilast on TNF-α production and dermatitis were superior to those of other topical PDE4 inhibitors: CP-80633, cipamfylline, and crisaborole. In pharmacokinetic studies using miniature pigs and rats, the concentrations of difamilast in the blood and brain after topical application were not sufficient to support pharmacological activity. This nonclinical study contributes to explain the efficacy and safety of difamilast with a sufficient therapeutic window in the clinical trials. SIGNIFICANCE STATEMENT: This is the first report on the nonclinical pharmacological profile of difamilast ointment, a novel topical PDE4 inhibitor that demonstrated utility in clinical trials in patients with atopic dermatitis. Difamilast, which has high PDE4 selectivity (especially for the PDE4B subtype), ameliorated chronic allergic contact dermatitis in mice after topical application, with a pharmacokinetic profile in animals that suggests few systemic side effects; thus, difamilast is a promising new therapeutic treatment for atopic dermatitis.

The Inhibition of Glycolysis in T Cells by a Jak Inhibitor Ameliorates the Pathogenesis of Allergic Contact Dermatitis in Mice

Allergic contact dermatitis (ACD) and atopic dermatitis (AD) develop through delayed-type hypersensitivity reactions mediated by T cells. The development of immunomodulatory drugs, such as Jak inhibitors (jakinibs), would be useful for the long-term management of these diseases due to their profile of favorable adverse effects. However, the efficacy of jakinibs for ACD treatment has not been fully determined under a variety of settings. Therefore, we evaluated the effects of ruxolitinib (Rux), a jakinib for Jak1 and Jak2, using a mouse ACD model. As a result, the lower numbers of immune cells including CD4+ T cells, CD8+ T cells, neutrophils and possibly macrophages as well as milder pathophysiological aspects have been observed in the inflamed skin of ACD with the administration of Rux. In addition, the treatment of differentiating T cells with Rux downregulated the level of IL-2-mediated glycolysis in vitro. Furthermore, symptoms of ACD did not develop in T cell-specific Pgam1-deficient mice whose T cells had no glycolytic capacity. Taken together, our data suggest that the downregulation of glycolysis in T cells by Rux could be an important factor for the suppression of ACD development in mice.

Rosmarinic acid ameliorates skin inflammation and pruritus in allergic contact dermatitis by inhibiting mast cell-mediated MRGPRX2/PLCγ1 signaling pathway.

Allergic contact dermatitis (ACD) is one of the most common dermatoses, which has high disease burden and quality of life impairment. Anti-histamine is not effective in a part of the ACD patients. Thus, the discovery of novel antipruritic therapy is of highly demand. In this study, we investigated the anti-pruritic effects of rosmarinic acid (RA) and explored the underlying mechanism. SPF Balb/c mice were randomly divided into control group, ACD model group, RA group (1.0mg/kg) and loratadine (LORA) group (1.5mg/kg). Back epidermal thickness was recorded. H&E staining was used for pathological observation. Mast cell degranulation was assessed by toluidine blue staining. ELISA assay was employed to detect cytokines levels. Cortistatin-14 (CST-14) and Mas-related G protein-coupled receptor X2 (MRGPRX2) expression was detetcted by RT-PCR and western blot. Molecular docking assay was used to predict the affinity of RA and MRGPRX2. Surface plasmon resonance (SPR) assay was used to verify structure affinity of RA and MRGPRX2. RA treatment significantly decreased epidermal keratinization and inflammatory cell infiltration in ACD mouse model. Administration of RA significantly reduced secretion of histamine, IL-13, and mRNA expression of CST-14. Furthermore, RA treatment increased mRNA expression of MRGPRX2. In addition, Molecular docking results predict that RA has a good affinity with MRGPRX2. RA displayed a structure affinity (KD=8.89×10-4) with MRGPRX2 by SPR. RA inhibited CST-14 and Compound 48/80 (C48/80)-induced mast cell activation via MRGPRX2-PLCγ1-PKC-NF-κB signaling pathway. RA exhibits anti-pruritic and anti-inflammatory effects in ACD mice by inhibiting MRGPRX2-PLCγ1-PKC-NF-κB signaling pathway. RA might emerge as a potential drug for the treatment of pruritus and skin inflammation in the setting of ACD.

Formaldehyde aggravates allergic contact dermatitis by facilitating NLRP3 inflammasome activation in macrophages.

Formaldehyde (FA) is known to be an environmental pollutant and contact sensitizer at 1% or 2% concentrations, which can induce inflammatory diseases such as allergic contact dermatitis (ACD). However, the aggravative effects of FA on ACD at legitimate low concentrations in cosmetics have not been studied. The activation of NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome in ACD was recently identified, and the inflammatory responses were attenuated by NLRP3 inhibition. Since non-cytotoxic concentrations of FA at 50 and 100μM were found to reinforce inflammatory responses in macrophages, the 0.05% low concentration of FA was applied to ACD mice induced by 2,4-dinitro-1-fluorobenzene. FA significantly exacerbated inflammatory responses and NLRP3 inflammasome activation, which was confirmed in RAW264.7 macrophages treated with FA at 50 and 100μM in vitro. Induction of mitochondrial reactive oxygen species, the common activation signal for NLRP3 inflammasome, was also observed in FA-treated macrophages. Inhibition of NLRP3 by MCC950 significantly attenuated the NLRP3 inflammasome activation induced by 100μM FA in vitro and alleviated FA-enhanced inflammatory responses in ACD mice. These results not only demonstrated that FA was able to aggravate the inflammatory responses of ACD by facilitating NLRP3 inflammasome activation in macrophages, which was likely to play important roles in FA-related sensitization, but also indicated that NLRP3 could be targeted to relieve FA-induced inflammation.

Deficiency of Autophagy-Related Gene 5 in Keratinocytes Leads to Aggravation of Epidermal Damage in 2,4-dinitrochlorobenzene-induced Allergic Contact Dermatitis

Objective: To determine whether keratinocyte-specific autophagy-related gene 5 (ATG5) deficiency can regulate apoptosis to inhibit skin damage in mice with 2,4-dinitrochlorobenzene (DNCB)-induced allergic contact dermatitis (ACD). Methods: This study involved keratinocyte-specific Atg5 conditional knockout (cKO) mice (Krt14cre/+-Atg5 flox/flox) and control mice (Krt14+/+-Atg5 flox/flox). We painted DNCB on the right ear of each mouse to induce ACD. Dermatitis scoring and measurements of ear weight and thickness were performed to evaluate inflammation levels. An immunohistochemical assay was performed to analyze immune cell infiltration. Histological study and TUNEL staining were performed to compare the differences in skin lesions between Atg5 cKO mice and control mice. Immunofluorescence and western blotting were used to examine the levels of ATG5 and apoptosis-related protein. The results were statistically analyzed by t test. Results: After DNCB stimulation of mice ears, we observed a more severe phenotype in Atg5 cKO mice than in control mice (dermatitis score: 7.5 ± 2.5884 vs. 3.25 ± 0.8216, P = 0.0033). Further analysis of ATG5 protein confirmed keratinocyte-specific ablation of Atg5 in cKO mice and showed that DNCB did not influence ATG5 expression. Immunohistochemistry assay revealed that the infiltrated immune cells were not involved in aggravation of the phenotype of DNCB-stimulated Atg5 cKO mice. However, the histological study (P = 0.0238), TUNEL staining (P = 0.0238), immunofluorescence (P = 0.0357), and western blotting showed that the increase in keratinocyte death, especially apoptosis, contributed to aggravation of the phenotype of DNCB-stimulated Atg5 cKO mice. Conclusion: Deficiency of Atg5 in keratinocytes increases apoptosis, aggravating skin damage in DNCB-induced ACD mice. This has no relationship with the involvement of immune cells.

Epimedin A ameliorates DNFB-induced allergic contact dermatitis in mice: Role of NF-κB/NLRP3-driven pyroptosis, Nrf2/HO-1 pathway, and inflammation modulation

AimsThe present study aimed to investigate the potential of epimedin A to ameliorate DNFB-induced allergic contact dermatitis (CD) and reveal its potential underlying mechanisms of action, emphasizing its role in modulating NF-κB/NLRP3, Nrf2/HO-1 pathways, and inflammation. Main methodsSeven-week-old BALB/c mice received epimedin A orally for 11 days at doses of 5, 10, or 20 mg/kg/day, starting from the seventh day of DNFB-inducing CD. Key findingsEpimedin A dose-dependently ameliorated DNFB-induced CD, as revealed by the repression of the mice's scratching behavior, dermatitis score, ear thickness and weight, and ear tissue's histopathological changes, and area percent of collagen fibers induced by DNFB. These potentials were due to the NF-κB/NLRP3 pathway suppression and the Nrf2 pathway enhancement, as demonstrated by the reduction of NF-κB, NLRP3, ASC, caspase-1, and 8 mRNA expression, and NF-κBp65, IL-1β, MDA levels, and NF-κBp65 binding activity, along with the enhancement of the Nrf2, HO-1, IκB-α, GSH levels, SOD activity, and Nrf2 binding activity. Besides, it suppressed ear tissues' NLRP3 and caspase-8 induced pyroptosis by suppressing the ear tissues' caspase-1, 8, GSDMD upregulation, and LDH activity. Additionally, it repressed the local inflammatory reaction of ear tissue, as evidenced by the reduction of the elevated inflammatory cytokines (IL-1β, IL-6, Il-4, TNF-α, and IFN-γ), the serum level of t-IgE, DNFB s-IgE, s-IgE/t-IgE ratio, and the abrogation of the ear tissues histopathological changes. SignificanceEpimedin A is a novel, hopeful, natural therapeutic agent for CD by modulating NF-κB/NLRP3, Nrf2 pathways, and inflammation.

Effects of Fisetin on Allergic Contact Dermatitis via Regulating the Balance of Th17/Treg in Mice.

Background Allergic contact dermatitis (ACD) is a form of chronic cutaneous inflammatory disease of immunological origin that has adverse impacts on patient quality of life, underscoring the need for the development of safe and effective therapeutic agents to treat affected individuals. Fisetin is a Chinese herbal preparation that reportedly exhibits antitumor, antioxidant, antimicrobial, anticoagulatory, and antimalarial activity. In the current report, the immunomodulatory activity of fisetin was appraised by assessing its impact on balance between regulatory T (Treg) and Th17 cells in an ACD model. Methods BALB/c mice (n = 60) were randomized into control, ACD model, CTX positive control (20 mg/kg), and fisetin treatment groups (three dose levels: 2, 4, or 8 mg/kg). ACD induction was achieved by sensitizing mice on the shaved ventral abdomen via the application of 5% DNFB (50 μL) on days 1 and 2, followed by rechallenge in the right ear with 5% DNFB (20 μL) on day 5. Beginning on day 1, immunized mice were intraperitoneally injected with the appropriate fisetin dose (in saline) once per day for 7 days. On day 7, ear swelling, transcription factor expression, Th17/Treg cell populations, and cytokine production were assessed in vivo. Results Fisetin treatment significantly suppressed ear swelling and associated inflammatory cell infiltration, besides reducing the production of Th17 cytokines (IL-17, TNF-α, and IL-6) and the expression of the Th17 lineage transcription factor RORγt while simultaneously enhancing Treg-specific cytokine production (TGF-β and IL-10) and the expression of the Treg lineage transcription factor Foxp3, thereby restoring the Th17/Treg cell in ACD mice. Conclusions These data indicate that fisetin exhibits immunomodulatory activity and can alter the Th17/Treg cell balance, highlighting its potential value as a treatment drug for ACD.

Regulation of eotaxin expression in skin allergic diseases.

IntroductionAs a key chemotactic factor during Eos recruitment on the allergic inflammation site, eotaxin is regarded as one of the important therapeutic targets.AimTo address the expression and regulation mechanism of eotaxin, which constitutes an important procedure in skin allergic disease and a target for drug therapy.Material and methodsAn allergic contact dermatitis (ACD) model of mouse was established. Immunohistochemical method (ICH) and flow cytometry method (FCM) were used to determine the amounts of CD4+ and CD8+ T cells and their ratios. The eotaxin mRNA and protein were evaluated by real-time PCR, ICH and western-blotting method. Nuclear factor-κB (NF-κB) nuclear translocation and STAT6 phosphorylation were studied by EMSA and western-blotting methods.ResultsWe confirmed that both CD4+ and CD8+ T cells in mouse blood and tissue increased during the allergic process, FBs was the main source for eotaxin under the allergic condition. Both TNF-α and IL-4 showed synergic effects on the up-regulation of eotaxin mRNA and protein in KC and FBs. Eotaxin can be expressed via NF-κB and STAT6 transcription after KC and FBs were stimulated by TNF-α and IL-4.ConclusionsThe obvious up-regulation of eotaxin expression in skin tissue of the mouse ACD model was confirmed, the exact expression site and dynamic process was determined both in vivo and in vitro. The eotaxin expression ability of FBs outperformed that of KC, and eotaxin expression can be regulated by TNF-α and IL-4 via NF-κB and STAT6. The overall findings may pave the way for discovering targets for new drugs and new therapeutic drugs for treating allergic diseases.

Discovery of Eucalyptin C, derived from the fruits of Eucalyptus globulus Labill., as a novel selective PI3Kγ inhibitor for immunosuppressive treatment

The fruits of Eucalyptus globulus Labill. are known to have a plenty of medicinal properties, such as anti-tumor, anti-inflammatory, and immunosuppressive activity. Our previous study found that the phloroglucinol-sesquiterpene adducts in the fruits of E. globulus were immunosuppressive active constituents, especially Eucalyptin C (EuC). Phosphoinositide 3-kinases-γ (PI3Kγ) plays a pivotal role in T cell mediated excessive immune responses. In this study, EuC was first discovered to be a novel selective PI3Kγ inhibitor with an IC50 value of 0.9 μmol·L-1 and selectivity over 40-fold towards the other PI3K isoforms. Molecular docking, molecular dynamics simulation, and cellular thermal shift assay showed that EuC bound to PI3Kγ. Furthermore, EuC suppressed the downstream of PI3Kγ to induce the apoptosis and inhibit the activation of primary spleen cells derived from allergic contact dermatitis mice. This work highlights the role of the fruits of E. globulus as a source of bioactive plant with immunosuppressive activity.

Type 2 immunity plays an essential role for murine model of allergic contact dermatitis with mixed type 1/type 2 immune response

BackgroundBoth human and mouse allergic contact dermatitis (ACD) frequently demonstrates a combined type 1 and type 2 immune response. However, the relative importance of type 2 immunity in this setting has been incompletely understood yet. ObjectiveTo explore an effector function of type 2 immunity in ACD with mixed type 1/type 2 immune response. MethodsGene expression characteristics of contact hypersensitivity (CHS) model was examined by quantitative polymerase chain reaction. Cytokine profile of T cells was analyzed by flow cytometry. The involvement of type 2 immunity was assessed by antibody-mediated cytokine neutralization and cell depletion. The role of specific subset of cutaneous dendritic cells was evaluated using diphtheria toxin-induced cell-depleting mouse strains. ResultsOxazolone-induced CHS revealed a combination of type 1/type 2 gene expression. The severity of oxazolone-induced CHS was ameliorated by neutralization of IL-4 but not of IFN-γ, indicating that type 2 immunity plays a dominant effector function in this mixed type 1/type 2 model. Mechanistically, type 2 effector immunity was mounted by CD301b+Langeirn− dermal dendritic cells in part through thymic stromal lymphopoietin-interleukin 7 receptor alpha signaling-dependent manner. ConclusionOur findings suggest the clinical rationale for targeting type 2 immunity as a relevant therapeutic strategy for the mixed immune phenotype of ACD.

Anti-allergy Effect of Sulfated Polysaccharide from Sargassum polycystum on Dinitrofluorobenzene Induced Allergic Contact Dermatitis in Mice

Background: Sargassum polycystum C. Agardh has potent antioxidant and antiinflammatory properties. However, its anti-allergic effect has not yet been reported. In this study, we investigated the anti-allergic effects of sulfated polysaccharide of S. polycystum (SPSP) in Dinitrofluorobenzene (DNFB)- induced allergic contact dermatitis animal model. Methods: SPSP was extracted through the hot water extraction method and was subjected to compositional analyses. For the Allergic Contact Dermatitis (ACD) model, symptoms were induced by the topical application of 0.5% DNFB on the shaved ventral skin of mice. SPSP (500, 1000, and 2000 mg/kg) and Prednisolone were orally administered for seven days after sensitization. Elicitation was performed seven days later with 0.2% DNFB. After this, ear thickness was measured at baseline and 24 hours post elicitation using a dial thickness gauge. Serum of mice was obtained 24 hours post elicitation, and the level of IFNγ and TNFα was quantified by enzyme-linked immunosorbent assays (ELISA). Results: SPSP afforded 33.6% carbohydrates, 23.7% sulfate, 7.5% protein, and 1.5% uronic acid contents. SPSP inhibited the ear swelling and cytokines (IFNγ and TNFα) production in DNFBinduced mice in a dose-dependent manner. In comparison with Prednisolone (p>0.05), the highest concentration (2000 mg/kg) of SPSP showed a comparable anti-allergic effect. Conclusion: These findings showed that the sulfated polysaccharide from S. polycystum is a potential natural source to treat allergic contact dermatitis. The effect is attributed to the polysaccharideprotein complex present in the extract, but further studies are needed to establish the exact mechanism of action of SPSP in the treatment of the disease.

Proteome Profile of Trigeminal Ganglion in Murine Model of Allergic Contact Dermatitis: Complement 3 Pathway Contributes to Itch and Pain Sensation.

Allergic contact dermatitis (ACD) is a common inflammatory dermatosis characterized by persistent itch and pain after topical contact with reactive chemicals. Although it has been long recognized as a type-IV hypersensitivity, its complexity of pathophysiology mechanism makes it still a clinical aporia in treatment. In this study, we aimed to identify crucial proteins involved in the nociceptive sensation of ACD. Based on a chemical-induced ACD murine model, we collected trigeminal ganglions of ACD and control mice for quantitative tandem mass tag (TMT)-labeling proteomic analysis. Immunohistochemistry was further practiced to validate the bioinformatic analysis. A total of 7685 proteins were identified and analyzed. Sixty-four proteins were significantly upregulated, and 75 proteins were downregulated in ACD mice. GO analysis demonstrated that the changed proteins were significantly enriched in terms of immune and peptidase activity in ACD mice. Proteins involved in the complement and coagulation cascades were notably changed in the KEGG enrichment analysis. The upregulation of complement component 3 (C3) in trigeminal satellite cells of ACD mice was further confirmed by immunohistochemistry. ACD upregulated C3 in trigeminal satellite cells. The complement system in sensory ganglion might play an essential role in forming pruritic and nociceptive sensations in ACD.