Mouse Model Of Atopic Dermatitis Research Articles

A CCR4 antagonist attenuates atopic dermatitis-like skin inflammation by inhibiting the recruitment and expansion of Th2 cells and Th17 cells.

CCR4 is a major trafficking receptor for T-helper (Th) 2 cells and Th17 cells and is considered as a potential therapeutic target for atopic dermatitis (AD). The CCR4 ligands CCL17 and CCL22 have been reported to be upregulated in the skin lesions of AD patients. Of note, thymic stromal lymphopoietin (TSLP), a master regulator of the Th2 immune response, promotes the expression of CCL17 and CCL22 in AD skin lesions. Here, we investigated the role of CCR4 in an AD mouse model induced by MC903, a TSLP inducer. Topical application of MC903 to ear skin increased the expression of not only TSLP but also CCL17, CCL22, the Th2 cytokine IL-4, and the Th17 cytokine IL-17A. Consistently, MC903 induced AD-like skin lesions as shown by increased epidermal thickness; increased infiltration of eosinophils, mast cells, type 2 innate lymphoid cells, Th2 cells, and Th17 cells; and elevated serum levels of total IgE. We also found increased expansion of Th2 cells and Th17 cells in the regional lymph nodes (LNs) of AD mice. Compound 22, a CCR4 inhibitor, ameliorated AD-like skin lesions with reduction of Th2 cells and Th17 cells in the skin lesions and regional LNs. We further confirmed that compound 22 diminished the expansion of Th2 cells and Th17 cells in the coculture of CD11c+ dendritic cells (DCs) and CD4+ T cells derived from the regional LNs of AD mice. Collectively, CCR4 antagonists may exhibit anti-allergic effects by inhibiting both the recruitment and expansion of Th2 cells and Th17 cells in AD.

Exosomes with overexpressed miR 147a suppress angiogenesis and infammatory injury in an experimental model of atopic dermatitis

Atopic dermatitis is defined as an intensely systemic inflammation among skin diseases. Exosomes derived from adipose-derived stem cells may be a novel cell-free therapeutic strategy for atopic dermatitis treatment. This study aims to elucidate the possible underlying mechanism of adipose-derived stem cells-exosomes harboring microRNA-147a in atopic dermatitis pathogenesis. BALB/c mice treated with Dermatophagoides farinae extract/2,4-dinitrochlorobenzene were defined as a mouse model of atopic dermatitis, either with inflamed HaCaT cells and HUVECs exposed with TNF-α/IFN-γ stimulation were applied for a cell model of atopic dermatitis. The concentrations of IL-1β and TNF-α in the supernatants were examined by ELISA. Cell viability and migration were assessed by MTT and Transwell assay. The apoptosis was examined using flow cytometry and TUNEL staining. The tube formation assay was employed to analyzed angiogenesis. The molecular regulations among miR-147a, MEF2A, TSLP and VEGFA were confirmed using luciferase reporter assay, either with ChIP. microRNA-147a was markedly downregulated in the serum and skin samples of atopic dermatitis mice, of which overexpression remarkably promoted HaCaT cell proliferation, meanwhile inhibiting inflammatory response and cell apoptosis. microRNA-147a in adipose-derived stem cells was subsequently overexpressed, and exosomes (Exos-miR-147a mimics) were collected. Functionally, exos-microRNA-147a mimics attenuated TNF-α/IFN-γ-induced HaCaT cell inflammatory response and apoptosis, and suppressed HUVECs angiogenesis. Encouraging, molecular interaction experiments revealed that exosomal microRNA-147a suppressed TNF-α/IFN-γ-induced HUVECs angiogenesis by targeting VEGFA, and exosomal microRNA-147a repressed HaCaT cells inflammatory injury through the MEF2A-TSLP axis. Mechanistically, exosomal microRNA-147a repressed pathological angiogenesis and inflammatory injury during atopic dermatitis progression by targeting VEGFA and MEF2A-TSLP axis. microRNA-147a-overexpressing adipose-derived stem cells-derived exosomes suppressed pathological angiogenesis and inflammatory injury in atopic dermatitis by targeting VEGFA and MEF2A-TSLP axis.

Calcitriol, an Active Form of Vitamin D3, Mitigates Skin Barrier Dysfunction in Atopic Dermatitis NC/Nga Mice.

Atopic dermatitis and psoriasis are prevalent chronic inflammatory skin diseases that are characterized by dysfunctional skin barriers and substantially impact patients' quality of life. Vitamin D3 regulates immune responses and keratinocyte differentiation and improves psoriasis symptoms; however, its effects on atopic dermatitis remain unclear. Here, we investigated the effects of calcitriol, an active form of vitamin D3, on an NC/Nga mouse model of atopic dermatitis. We observed that the topical application of calcitriol decreased the dermatitis scores and epidermal thickness of NC/Nga mice with atopic dermatitis compared to untreated mice. In addition, both stratum corneum barrier function as assessed by the measurement of transepidermal water loss and tight junction barrier function as evaluated by biotin tracer permeability assay were improved following calcitriol treatment. Moreover, calcitriol treatment reversed the decrease in the expression of skin barrier-related proteins and decreased the expression of inflammatory cytokines such as interleukin (IL)-13 and IL-33 in mice with atopic dermatitis. These findings suggest that the topical application of calcitriol might improve the symptoms of atopic dermatitis by repairing the dysfunctional epidermal and tight junction barriers. Our results suggest that calcitriol might be a viable therapeutic agent for the treatment of atopic dermatitis in addition to psoriasis.

CTLA-4 suppresses hapten-induced contact hypersensitivity in atopic dermatitis model mice

Atopic dermatitis (AD) patients with skin barrier dysfunction are considered to be at a higher risk of allergic contact dermatitis (ACD), although previous studies showed that attenuated ACD responses to strong sensitizers in AD patients compared to healthy controls. However, the mechanisms of ACD response attenuation in AD patients are unclear. Therefore, using the contact hypersensitivity (CHS) mouse model, this study explored the differences in CHS responses to hapten sensitization between NC/Nga mice with or without AD induction (i.e., non-AD and AD mice, respectively). In this study, ear swelling and hapten-specific T cell proliferation were significantly lower in AD than in non-AD mice. Moreover, we examined the T cells expressing cytotoxic T lymphocyte antigen-4 (CTLA-4), which is known to suppress T cell activation, and found a higher frequency of CTLA-4+ regulatory T cells in draining lymph node cells in AD than in non-AD mice. Furthermore, the blockade of CTLA-4 using a monoclonal antibody eliminated the difference in ear swelling between non-AD and AD mice. These findings suggested that CTLA-4+T cells may contribute to suppressing the CHS responses in AD mice.

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.

Anti-Atopic Effect of Isatidis Folium Water Extract in TNF-α/IFN-γ-Induced HaCaT Cells and DNCB-Induced Atopic Dermatitis Mouse Model.

Isatidis folium or Isatis tinctoria L. is a flowering plant of the Brassicaceae family, commonly known as woad, with an ancient and well-documented history as an indigo dye and medicinal plant. This study aimed to evaluate the anti-atopic dermatitis (AD) effects of Isatidis folium water extract (WIF) using a 2,4-dinitrochlorobenzene (DNCB)-induced AD-like mouse model and to investigate the underlying mechanism using tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ)-activated HaCaT cells. Oral administration of WIF reduced spleen weight, decreased serum IgE and TNF-α levels, reduced epidermal and dermal thickness, and inhibited eosinophil and mast cell recruitment to the dermis compared to DNCB-induced control groups. Furthermore, oral WIF administration suppressed extracellular signal-regulated kinase and p38 mitogen-activated protein kinase protein expression levels, p65 translocation from the cytoplasm to the nucleus, and mRNA expression of TNF-α, IFN-γ, interleukin (IL)-6, and IL-13 in skin lesion tissues. In HaCaT cells, WIF suppressed the production of regulated upon activation, normal T cell expressed and secreted (RANTES), thymus and activation-regulated chemokine (TARC), macrophage-derived chemokine (MDC), MCP-1, and MIP-3a, which are inflammatory cytokines and chemokines related to AD, and inhibited the mRNA expression of RANTES, TARC, and MDC in TNF-α/IFN-γ-stimulated HaCaT cells. Overall, the results revealed that WIF ameliorated AD-like skin inflammation by suppressing proinflammatory cytokine and chemokine production via nuclear factor-κB pathway inhibition, suggesting WIF as a potential candidate for AD treatment.

Combination Therapy with Betamethasone and Josamycin Demonstrates Superior Therapeutic Efficacy in an NC/Nga Mouse Model of Atopic Dermatitis.

We have previously demonstrated the excellent bactericidal activity of josamycin against Staphylococcus aureus isolated from patients with atopic dermatitis (AD), with therapeutic efficacy equal to that of betamethasone. The present study was designed to evaluate the effectiveness of combination therapy with betamethasone and josamycin for AD. Betametasone (0.1%) and josamycin (0.1%) were topically administered to NC/Nga mice with severe AD-like skin lesions. Skin severity scores, histological changes in skin lesions, and serum immunoglobulin E (IgE) levels were assessed as indicators of therapeutic efficacy. Topical treatment with both drugs suppressed the skin severity score to a greater degree than betamethasone alone. This was associated with a reduction of epidermal thickening, a reduced density of dermal cellular infiltration, a decreased mast cell count in the dermis, and a reduced serum IgE level. In addition, both drugs in combination markedly reduced the expression of interferon (IFN)-γ and interleukin (IL)-4 in auricular lymph node cells, as well as the S. aureus count on the lesioned skin. These results show that simultaneous topical application of both drugs can ameliorate severe AD-like skin lesions in NC/Nga mice. It is suggested that combination therapy with betamethasone and josamycin would be beneficial for control of severe AD lesions colonized by S. aureus by inhibiting the development of both T helper (Th) type 1 (Th1) and Th2 cells and also through elimination of superficially located S. aureus.

Therapeutic efficacy and mechanism of a solubilized Sturgeon oil in a mouse model of house dust mite-induced atopic dermatitis

Abstract The therapeutic effect and action mechanism of solubilized Sturgeon oil (SSO) against atopic dermatitis (AD) were examined in NC/Nga mice. SSO was prepared from the fish oil obtained from Sturgeons using physical solubilization processes. AD was induced by topical application of house dust mite (HDM) extract on the dorsal skin of NC/Nga mice, and then treated with SSO. SSO exerted potent therapeutic activity on AD symptoms. Histological analysis revealed that SSO reduced epidermal hyperplasia and suppressed infiltration of mast cells and eosinophils in the dorsal skin. In addition, SSO significantly reduced the serum total IgE and HDM-specific IgE levels in AD-induced NC/Nga mice. Analysis of the dorsal skin tissues showed that SSO significantly downregulated the expression levels of IL-4, 5, 13, 17A and COX-2, while upregulated the expression levels of IL-10 and filaggrin. In vitro studies also showed that SSO suppressed the production of Th2 cytokines including IL-4, 5 and 13, while increasing the production of IL-10, from anti-CD3/CD28-stimulated Th2 cells. These results show that SSO exerts therapeutic effect on AD in NC/Nga mice through Th2-related immunomodulatory activities.

Poly(Methylqinjgtebie Methacrylate) Nanoparticles-Based HIF-1α Carrier Reduces Epithelial Cell Activation and Adhesion Molecule Expression in Atopic Dermatitis

Atopic dermatitis (AD) is a skin disease. This study established a mouse AD model to investigate the impact of PMMA (Poly(methyl methacrylate)) nanoparticles (PMMANPs) on epithelial cells. Nice (n = 30) receiving no intervention were taken as a healthy group, while the other animals (n = 30) were placed in the model group and sensitized with 2,4-Dinitrochlorobenzene (DNCB) acetone solution to establish the AD model. Skin epithelial cells on the backs of mice were assigned into blank control group, negative control group, PMMA group, Hypoxia-Inducible Factor (HIF)-1α group, and PMMA + HIF-1α group, followed by analysis of epithelial cell density by toluidine blue staining, HIF-1α, ICAM-1 (Intercellular Adhesion Molecule 1) and VCAM-1 (Vascular cell adhesion molecule-1) expressions. The back skin of mice in the model group appeared with edema, erythema, and desquamation, with increased number of scratches and pathological changes such as skin keratinization, inflammatory cell infiltration, and epidermal thickening, indicating successful establishment of the AD model. In comparison, the epithelial cell density of the PMMA group, HIF-1α group, and PMMA+HIF-1α group (10.08±0.32, 10.50±0.34, 7.52±0.28) decreased significantly (P <0.05), with lowest density in the PMMA+HIF-1α group. Importantly, treatment with HIF-1α, PMMANPs, and HIF-1α-loaded PMMANPs greatly elevated HIF-1α levels (3.25±0.08, 3.69±0.07, 4.46±0.10) while decreased ICAM-1 and VCAM-1 levels (794.02±56.27, 788.36±49.38, 744.64±36.40). Furthermore, combined treatment obtained highest HIF-1α expression and lowest ICAM-1 and VCAM-1 level (P <0.05) expressions. Collectively, the PMMANPs carrying HIF-1α VCAM-1 exerted protective role in the recovery of AD, and these findings suggest that, the HIF-1α can be used as a target gene for AD treatment.

Glabridin ameliorates DNFB induced atopic dermatitis by suppressing MAPK/NF κB signaling pathways in mice

Purpose: To investigate the anti-inflammatory mechanism of action of glabridin (GBD) isolated from glycyrrhizae radix et rhizoma (Glycyrrhiza glabra L.) using atopic dermatitis (AD) mouse model. Methods: Nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways were investigated. The dorsal skin and serum of 2,4-dinitrofluorobenzene (DNFB)-induced AD mice were used to determine the levels of various inflammatory cytokines, including interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-4, IL-5, IL-6, IL-13, and immunoglobulin E (IgE) by enzyme-linked immunosorbent assay (ELISA). The relative levels of inflammation-associated mRNA and signaling pathways were determined by real time-polymerase chain reaction (RT-PCR) and western blotting, respectively. Hematoxylin and eosin (H&E) staining was used to assess the effect of GBD on tissue thickening and inflammatory cell infiltration in mice with AD. Results: Glabridin significantly relieved dorsal skin thickening, scabbing, and bleeding, and reduced the infiltration of inflammatory cells in mice with AD (p < 0.05). The levels of IFN-γ, TNF-α, IL-4, IL-5, IL-6, IL-13, and IgE were significantly reduced (p < 0.05 or 0.01). Moreover, the relative levels of IL-6 and IFN-γ mRNA showed a significant decrease (p < 0.01). Furthermore, GBD inhibited phosphorylation of MAPK signaling pathway and activation of NF-κB (p < 0.05 or 0.01). Conclusion: Glabridin exerts an inhibitory effect on AD by blocking MAPK and NF-κB signaling pathways. This finding highlights the relationship between traditional Chinese medicine and modern AD therapeutic methods, which should be further investigated for its potential to be developed as an external anti-AD medicine.

716 Beneficial effects of ultra fine bubble shower on a mouse model of atopic dermatitis

716 Beneficial effects of ultra fine bubble shower on a mouse model of atopic dermatitis

780 A novel antimicrobial peptide derived from insulin-like growth factor-binding protein 5 (AMP-IBP5) alleviates dermatitis-like symptoms in a mouse model of atopic dermatitis

780 A novel antimicrobial peptide derived from insulin-like growth factor-binding protein 5 (AMP-IBP5) alleviates dermatitis-like symptoms in a mouse model of atopic dermatitis

867 Activation of STING pathway in the sensory neuron regulates the pruritus in atopic dermatitis mouse model

867 Activation of STING pathway in the sensory neuron regulates the pruritus in atopic dermatitis mouse model

Abstract 5133: Oxazolone induced atopic dermatitis mouse model using hIL-4/hIL-4Ra double knock-in mice, a preclinical mouse model for evaluating Dupilumab biosimilars

Abstract Background. Th2 cytokines (e.g. IL-4, IL-5, IL13) drive defined allergic reactions and various autoimmune and inflammatory diseases including atopic dermatitis (AD), asthma and rhinitis. IL-4Ra is a receptor shared by both IL-4 and IL-13, thus blocking of IL-4Ra could prevent both IL-4 or IL-13 mediated Th2 inflammatory response. Dupilumab (Dupixent) is a humanized anti-IL-4Ra monoclonal antibody which binds to human IL-4Ra and attenuates IL-4/IL-13 mediated Th2 inflammation. It has been approved for treating moderate to severe AD and asthma. However, since Dupilumab isn’t cross-reacting to mouse IL-4Ra, there is an unmet need for a robust mouse model to evaluate Dupilumab biosimilars at preclinical stages. In this study, we described an oxazolone induced AD model in hIL-4/hIL-4Ra double knock-in mice and its application to evaluate Dupilumab and its biosimilars. Methods. The oxazolone induce AD mouse model was established in hIL-4/hIL-4Ra double knock-in mice by repeated topical applications of Oxazolone on ears. Oxazolone-induced mice received subcutaneous injection of Dupilumab at 25 mg/kg or 50 mg/kg. Dermatitis activity was assessed by measuring ear thickness, ear skin erosion, redness and scaling every other day. Serum were collected at the study end and IgE levels were measured by ELISA. In addition, spleens were also collected and their weights were compared. Ear were collected at study end and proceeded with cytokine analysis and pathology evaluation. Results. Repeated topical application of oxazolone on mouse ears induced AD-like phenotypes including ear skin swelling, erythema and scaling, drastic elevation of IgE in serum, excessive production of human IL-4 cytokine as well as excessive inflammatory cell infiltration in ear skin, which suggests oxazolone is able to induce AD in this hIL-4/hIL-4Ra double knock-in mice. Subcutaneous injection of Dupilumab at two different doses levels, 25 mg/kg and 50 mg/kg successfully ameliorated ear skin swelling, erythema and scaling at the study end. In addition, Dupilumab at both dose levels significantly reduced the IgE level in serum and mitigated the inflammatory cell infiltration, e.g. eosinophil infiltration, in mouse ear. Furthermore, Dupilumab treatment significantly reduced mouse IL-6 and mouse KC/GRO levels in mouse ear. However, Dupilumab at both dose levels did not change the serum levels of human IL-4 as well as some other Th1 cytokines such as IFN-γ, IL-1β, TNF-α, etc. in mouse ear. Conclusion. In summary, repeated challenge with Oxazolone in hIL-4/hIL-4Ra double knock-in mice resulted in the development of AD with a Th2-like hypersensitivity, mimicking the key features and pathology of the human disease, which responded to standard of care treatment Dupilumab. This provides a valuable translational model for the evaluation of future biosimilars of Dupilumab. Citation Format: Tao Yang, Rongfei Lu, Xiaofei Xu, Likun Zhang, Dawei Wang, Xinhe Feng, Xiaoyu An, Jessie (Jingjing) Wang, Xianfei He, Carl K. Edwards. Oxazolone induced atopic dermatitis mouse model using hIL-4/hIL-4Ra double knock-in mice, a preclinical mouse model for evaluating Dupilumab biosimilars. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5133.

Autologous Th2-polarized lymphocytes induce atopic dermatitis lesions in non-atopic human skin xenotransplants.

The key signals that suffice to induce atopic dermatitis (AD) in human skin remain incompletely understood. Also, current mouse models reflect human AD only unsatisfactorily. Therefore, we have asked whether a humanized AD mouse model can be developed that reflects human AD more faithfully and permit to identify key signals that suffice to induce AD lesions in previously healthy human skin in vivo. Healthy human skin from non-atopic donors was transplanted onto SCID/beige mice. After xenotransplant reinnervation by mouse sensory nerve fibers had occurred, mixed autologous human Th2 CD4+ and Tc2 CD8+ T cells that had been pretreated in vitro with IL-2, IL-4, and LPS were injected intradermally into the xenotransplants without skin barrier disruption. Injected non-atopic xenotransplants rapidly developed a morphological, functional, and immunological phenocopy of human AD lesions regarding skin barrier defects, immunopathology including intraepidermal eosinophils, mast cell activation, increase of thymic stromal lymphopoietin, eotaxin-1 and type 2 cytokine circuits, and even showed characteristic neuroimmunological abnormalities such as ß2-adrenergic receptor downregulation. The experimentally induced AD lesions in human skin responded to standard AD therapy (topical dexamethasone or tacrolimus; systemic anti-IL-4Rα antibody [dupilumab]), and relapsed when neurogenic skin inflammation was induced by exposing mice to perceived stress. This new animal model uniquely mimics the complexity of human AD and its clinical response to standard therapy and psychoemotional stressors in vivo, and shows that Th2-polarized lymphocytes associated with excessive IL-4Rα-mediated signaling suffice to induce human AD skin lesions, while atopy and epidermal barrier disruption are dispensable.

TMEM232 promotes the inflammatory response in atopic dermatitis via the nuclear factor-κB and signal transducer and activator of transcription 3 signalling pathways.

Our group previously found that the transmembrane protein 232 (TMEM232) gene was associated with atopic dermatitis (AD) by genome-wide association study and fine mapping study. However, its function is unclear so far. To investigate the roles and mechanisms of TMEM232 in AD. The expression of TMEM232 was investigated in skin lesions of patients with AD, the MC903-induced AD mouse model, human primary keratinocytes and immortalized human keratinocyte cell line (HaCaT) cells stimulated with different inflammatory factors. The role of TMEM232 in AD was analysed in HaCaT cells and Tmem232 knockout (Tmem232-/-) mice. Tmem232-specific small interfering RNA (siRNA) was used to evaluate its therapeutic potential in the AD mouse model. The expression of TMEM232 was significantly increased in skin lesions of patients with AD, the MC903-induced AD mouse model and human primary keratinocytes and HaCaT cells stimulated with different inflammatory factors compared with controls. In the presence of MC903, Tmem232-/- mice exhibited significantly reduced dermatitis severity, mast-cell infiltration in the back, and expression of T-helper (Th)1 and Th2-related inflammatory factors in skin tissue compared with wild-type mice. In vitro and in vivo experiments further showed that upregulation of TMEM232 in AD exacerbated the inflammation response through activating the pathway of nuclear factor-κB and signal transducer and activator of transcription (STAT) 3, and was regulated by the interleukin-4/STAT6 axis, which formed a self-amplifying loop. Finally, topical application of Tmem232 siRNA markedly ameliorated AD-like lesions in the AD model. This study is the first to outline the function of TMEM232. It is involved in regulating inflammation in AD and may be a potential target for AD treatment.

Osthole relieves skin damage and inhibits chronic itch through modulation of Akt/ZO-3 pathway in atopic dermatitis

Atopic dermatitis (AD) is the most prevalent chronic inflammatory skin condition and significantly reduces quality of life. Tight junction (TJ), which is located directly beneath the stratum corneum, maintains skin barrier function and aids in the identification of the cell's "territory". We evaluated seventeen TJ related genes to explore AD related alterations of TJ. Remarkably, we found that the expression of ZO-3, a gene that had not been linked to the development of TJ in AD, was significantly down-regulated in the skin of AD mice and patients. siRNA mediated knock-down of ZO-3 significantly decreased transepithelial electrical resistance in HaCaT cells, demonstrating that ZO-3 is essential to epidermal barrier function. In addition to ZO-3 downregulation, protein kinase B (Akt) phosphorylation was increased in the skin of AD mice. We further confirmed an inverse relationship between Akt phosphorylation and ZO-3 expression in AD using HaCaT cells and mouse model. Finally, we tested the efficacy of osthole as a treatment for AD in mice and HaCaT cells. Osthole inhibits Akt phosphorylation, and thereby enhances ZO-3 expression in mouse models of AD, resulting in greatly lessened AD associated skin damage and chronic itch, and osthole also increased the expression of ZO-3 in HaCaT cells by inhibiting the phosphorylation of Akt. Together, we established that ZO-3 is essential for the development of TJ in AD skin and HaCaT cells, and our findings provide fresh support for osthole's ability to protect ZO-3 expression and the epidermal barrier in AD.

Potential Anti-Allergy and Immunomodulatory Properties of Lactococcus lactis LB 1022 Observed In Vitro and in an Atopic Dermatitis Mouse Model.

Lactococcus lactis is a lactic acid bacterium and used in the dairy food industry. The ameliorating effects of Lactobacillus species on atopic dermatitis (AD) have been extensively studied, but the specific effect of L. lactis strains has not yet been investigated. In this study, the efficacy of L. lactis LB 1022, isolated from natural cheese, was evaluated using RAW 264.7, HMC-1 and HaCaT cell lines and an ovalbumin-sensitized AD mouse model. L. lactis LB 1022 exhibited nitric oxide suppression and anti-allergy and anti-inflammatory activity in vitro. Oral administration of L. lactis LB 1022 to AD mice significantly reduced the levels of IgE, mast cells, and eosinophils, and a range of T cell-mediated T helper Th1, Th2, and Th17-type cytokines under interleukin (IL)-10, transforming growth factor-β (TGF-β), thymus and activation-regulated chemokine (TARC), and thymic stromal lymphopoietin (TSLP). In addition, L. lactis LB 1022 treatment increased the concentration of short-chain fatty acids. Overall, L. lactis LB 1022 significantly modulated AD-like symptoms by altering metabolites and the immune response, illustrating its potential as candidate for use in functional food supplements to alleviate AD.

Acid-sensing ion channel 3 is required for agmatine-induced histamine-independent itch in mice.

Itch is a common symptom of many skin and systemic diseases. Identifying novel endogenous itch mediators and the downstream signaling pathways involved will contribute to the development of new strategies for the treatment of chronic itch. In the present study, we adopted behavioral testing, patch clamp recording and metabonomics analysis to investigate the role of agmatine in itch and the underlying mechanism. Behavioral analysis was used to evaluate the establishing of acute and chronic itch mice model, and to test the effects of different drugs or agents on mice itch behavior. Western blotting analysis was used to test the effect of agmatine on phosphorylation of ERK (p-ERK) expression in the spinal cord. Patch clamp recording was used to determine the effect agmatine on the excitability of DRG neurons and the role of ASIC3. Finally, the metabonomics analysis was performed to detect the concentration of agmatine in the affected skin under atopic dermatitis or psoriasis conditions. We fused a mouse model and found that an intradermal injection of agmatine (an endogenous polyamine) into the nape of the neck or cheek induced histamine-independent scratching behavior in a dose-dependent manner. In addition, the ablation of nociceptive C-fibers by resiniferatoxin (RTX) abolished agmatine-induced scratching behavior. However, agmatine-induced itch was not affected by the pharmacological inhibition of either transient receptor potential vanilloid 1 (TRPV1) or transient receptor potential ankyrin 1 (TRPA1); similar results were obtained from TRPV1-/- or TRPA1-/- mice. Furthermore, agmatine-induced itch was significantly suppressed by the administration of acid-sensing ion channel 3 (ASIC3) inhibitors, APETx2 or amiloride. Agmatine also induced the upregulation of p-ERK in the spinal cord; this effect was inhibited by amiloride. Current clamp recording showed that the acute perfusion of agmatine reduced the rheobase and increased the number of evoked action potentials in acute dissociated dorsal root ganglion (DRG) neurons while amiloride reversed agmatine-induced neuronal hyperexcitability. Finally, we identified significantly higher levels of agmatine in the affected skin of a mouse model of atopic dermatitis (AD) when compared to controls, and the scratching behavior of AD mice was significantly attenuated by blocking ASIC3. Collectively, these results provide evidence that agmatine is a novel mediator of itch and induces itch via the activation of ASIC3. Targeting neuronal ASIC3 signaling may represent a novel strategy for the treatment of itch.

A Mouse Model of MC903-Induced Atopic Dermatitis.

Atopic dermatitis (AD) is a chronic, relapsing, and extremely pruritic inflammatory skin disease with a particular impact on children. AD pathogenesis is not yet fully understood, and there is no curative treatment for this disease. Therefore, several genetically or chemically-induced AD mouse models have been developed. These preclinical mouse models are an indispensable research tool for studying AD pathogenesis and evaluating the efficacy of new candidate AD therapeutics. A commonly used mouse model of AD has been developed using the topical application of a low-calcemic analog of vitamin D3, MC903, to induce AD-like inflammatory phenotypes that closely resemble human AD. Moreover, this model shows a minimal effect on systemic calcium metabolism that is observed in the vitamin D3-induced AD model. Thus, an expanding number of studies use the MC903-induced AD model to interrogate AD pathobiology in vivo and to test new candidate small molecule and monoclonal antibody therapies. This protocol describes in detail functional measurements including the measurement of skin thickness, which is a surrogate marker for ear skin inflammation, as well as itch assessment, histological evaluation to assess the structural changes associated with AD skin inflammation, and preparation of single-cell suspensions from ear skin and draining lymph nodes for the assessment of inflammatory leukocyte subset infiltration in these tissues using flow cytometry. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol: Topical application of MC903 induces AD-like skin inflammation Support Protocol 1: Measurement of ear skin thickness Support Protocol 2: Itch assessment Support Protocol 3: Dissection of ear skin and ear draining lymph nodes Support Protocol 4: Histological evaluation and quantification Support Protocol 5: Preparation of single-cell suspension from ear skin and draining lymph nodes for the assessment of inflammatory immune cell infiltration using flow cytometry.