Murine Model Of Contact Hypersensitivity Research Articles

Hochuekkito exerts the anti-allergic effects via activating regulatory T cells in a murine model of contact hypersensitivity.

Hochuekkito (HET) is a Kampo prescription, used for the clinical treatment of skin diseases such as atopic dermatitis (AD), in Japan. Oral administration of HET exerts anti-allergic effects in an experimental dermatitis mice model and in patients with atopic dermatitis; however, the mechanism underlying the anti-allergic effects of HET is still unclear. Therefore, we investigated the immunopharmacological properties of the anti-allergic actions of HET using a 2,4,6-trinitrochlorobenzene (TNCB)-induced murine contact hypersensitivity (CHS) model and adoptive cell transfer experiments. Oral administration of HET (1.4g/kg) exhibited anti-allergic effects in a TNCB-induced CHS model via activation of Tregs; this activation was observed even without antigen sensitization in donor mice. Activation was dependent on the duration of HET administration and required at least 4days of dosing. In addition, the anti-allergic effects of HET through the activation of Tregs were not antigen specific. Flow cytometry results indicated that the proportion of CD4+CD25+Foxp3+ cells in the splenic lymphocytes increased after oral administration of HET. Therefore, oral administration of HET induced both inducible regulatory T cells (iTregs) and thymus-derived naturally occurring regulatory T cells (nTregs). Ginseng radix and Bupleuri radix were involved in the anti-allergic actions of HET through the induction and/or activation of Tregs; Bupleuri radix participated in the activation of nTregs. In conclusion, our findings suggest that HET exerts the anti-allergic effects through the induction and/or activation of Tregs. These findings elucidate the usefulness of HET as an immunomodulator.

Topical Photodynamic Therapy Generates Bioactive Microvesicle Particles: Evidence for a Pathway Involved in Immunosuppressive Effects

Although effective in treating actinic damage, topical photodynamic therapy (PDT) has been shown to be immunosuppressive through unknown mechanisms, which could potentially limit its effectiveness. Multiple types of environmental stressors, including PDT, can produce the immunosuppressive lipid mediator platelet-activating factor (PAF). Because PAF can produce subcellular microvesicle particles (MVPs), these studies tested whether PDT can generate PAF and MVP release and whether these are involved in PDT-induced immunosuppression. Previously, topical PDT using blue light and 5-aminolevulinic acid was found to be a potent stimulus for PAF production in mice and human skin explants and human patients, and we show that experimental PDT also generates high levels of MVP. PDT-generated MVPs were independent of the PAF receptor but were dependent on the MVP-generating enzyme acid sphingomyelinase. Patients undergoing topical PDT treatment to at least 10% of body surface area showed local and systemic immunosuppression as measured by inhibition of delayed-type hypersensitivity reactions. Finally, using a murine model of contact hypersensitivity, PDT immunosuppression was blocked by genetic and pharmacologic inhibition of acid sphingomyelinase and genetic inhibition of PAF receptor signaling. These studies describe a mechanism involving MVP through which PDT exerts immunomodulatory effects, providing a potential target to improve its effectiveness.

Sensory neuron-expressed TRPC3 mediates acute and chronic itch.

Chronic pruritus is a prominent symptom of allergic contact dermatitis (ACD) and represents a huge unmet health problem. However, its underlying cellular and molecular mechanisms remain largely unexplored. TRPC3 is highly expressed in primary sensory neurons and has been implicated in peripheral sensitization induced by proinflammatory mediators. Yet, the role of TRPC3 in acute and chronic itch is still not well defined. Here, we show that, among mouse trigeminal ganglion (TG) neurons, Trpc3 mRNA is predominantly expressed in nonpeptidergic small diameter TG neurons of mice. Moreover, Trpc3 mRNA signal was present in most presumptively itch sensing neurons. TRPC3 agonism induced TG neuronal activation and acute nonhistaminergic itch-like and pain-like behaviors in naive mice. In addition, genetic deletion of Trpc3 attenuated acute itch evoked by certain common nonhistaminergic pruritogens, including endothelin-1 and SLIGRL-NH2. In a murine model of contact hypersensitivity (CHS), the Trpc3 mRNA expression level and function were upregulated in the TG after CHS. Pharmacological inhibition and global knockout of Trpc3 significantly alleviated spontaneous scratching behaviors without affecting concurrent cutaneous inflammation in the CHS model. Furthermore, conditional deletion of Trpc3 in primary sensory neurons but not in keratinocytes produced similar antipruritic effects in this model. These findings suggest that TRPC3 expressed in primary sensory neurons may contribute to acute and chronic itch through a histamine independent mechanism and that targeting neuronal TRPC3 might benefit the treatment of chronic itch associated with ACD and other inflammatory skin disorders.

Location Bias Contributes to Functionally Selective Responses of Biased CXCR3 Agonists to Regulate Inflammation

G Protein‐Coupled Receptors (GPCRs) represent the largest and most diverse family of cell receptors in the human genome and are targeted by ~35% of all FDA‐approved drugs. GPCR signaling is mediated by various effectors, including G proteins, β‐arrestins, and GPCR kinases (GRKs). Recent studies have uncovered that different ligands can bind to the same GPCR and differentially activate specific signaling pathways, a phenomenon known as biased agonism. Most research has focused on characterizing biased agonism at the plasma membrane, but GPCRs are also known to traffic to and signal from a variety of subcellular compartments. To determine if GPCR subcellular localization contributes to biased signaling, we studied how the chemokine family GPCR CXCR3 signals from endosomes following stimulation by the three endogenous ligands CXCL9, CXCL10, and CXCL11.We determined that the biased ligands of CXCR3 promote different amounts of receptor mediated endocytosis and also show markedly different G protein and β‐arrestin signaling profiles at both the plasma membrane and the endosome. The biased activation of G proteins and β‐arrestins promotes differential activation of cytoplasmic and nuclear ERK1/2, as well as cellular transcription in both HEK293 cells and primary CD8+ T‐cells. Inhibition of receptor internalization greatly diminishes the biased signaling observed between the endogenous chemokines. Finally, we demonstrate in a murine model of contact hypersensitivity that receptor internalization is a key component of the ability of a synthetic β‐arrestin biased CXCR3 agonist to potentiate the inflammatory response. The present study shows the CXCR3 biased ligands induce unique signaling profiles at the plasma membrane and the endosome, and that signaling from endosomes greatly contributes to the overall biased responses seen at CXCR3. These results demonstrate that signaling from subcellar compartments is a critical component of GPCR signaling. Our findings have implications in the development of pharmaceutical drugs targeting chemokine receptors and other GPCRs.

Analysis of Granulocyte-Macrophage Colony-Stimulating Factor-Producing T Helper Cells in a Mouse Model of Contact Hypersensitivity.

Parallel to traditional Th1/Th2/Th17/Treg lineages, granulocyte-macrophage colony-stimulating factor-producing T helper (Th-GM) cells have been identified as a distinct subset of T helper cells (GM-CSF+ IFN-γ- IL-17A- IL-22- effector CD4+ T cells) in human and mice. Contact hypersensitivity (CHS) is considered an excellent animal model for allergic contact dermatitis (ACD) in human, manifesting an intact T cell-mediated immune response. To provide a standardized and comprehensive assay to analyze the Th-GM cell subset in the T cell-dependent immune response in vivo, a murine CHS model was induced by sensitization/challenge with a reactive, low-molecular-weight, organic hapten, 2,4-dinitrofluorobenzene (DNFB). The Th-GM subset in effector CD4+ T cells generated upon immunization with the hapten was analyzed by flow cytometry. We found that Th-GM was mainly expanded in lesions and draining lymph nodes in the DNFB-induced CHS mouse model. This method can be applied to further study the biology of Th-GM cells and pharmacological research of therapeutic strategies centered on GM-CSF in various conditions, such as ACD.

Juzentaihoto Exerts Anti-Allergic Effects by Inhibiting Effector T-Cell Activation and Inducing and/or Activating Regulatory T Cells in a Murine Model of Contact Hypersensitivity

Background: Juzentaihoto (JTT) is a Kampo prescription that has been used clinically for treating skin diseases such as atopic dermatitis in Japan. We have previously studied the anti-allergic effects of JTT on 2,4,6-trinitrochlorobenzene (TNCB)-induced contact hypersensitivity (CHS) in mice and demonstrated that it significantly suppresses ear swelling in a dose-dependent manner. However, the mechanism underlying the anti-allergic actions of JTT is obscure. Methods: We investigated the mechanism underlying the anti-allergic effects of JTT using a TNCB-induced murine CHS model and adoptive cell transfer experiments. Results: We showed that the anti-allergic effects of JTT are due to inhibition of effector T-cell activation and induction and/or activation of regulatory T cells. Furthermore, ex vivo experiments confirmed the effect of JTT on the activation of effector T cells and regulatory T cells, as interferon-γ production decreased, whereas interleukin (IL)-10 production increased, in the cultured lymphocytes obtained from 5% TNCB-sensitized mice treated with anti-CD3ε and anti-CD28 monoclonal antibodies. Flow cytometry showed that the CD4⁺CD25⁺Foxp3⁺, CD4⁺CD25⁺Foxp3⁻, and CD8⁺CD122⁺ cell population increased after oral administration of JTT. Finally, the anti-allergic effect of JTT by inducing and/or activating regulatory T cells (Tregs) was confirmed to be mediated by IL-10 through in vivo neutralization experiments with anti-IL-10 monoclonal antibodies. Conclusion: We suggested that JTT exerts anti-allergic effects by regulating the activation of effector T cells and Tregs involved in murine CHS model.

Orengedokuto exerts anti-allergic effects via inhibition of effector T cell activation in a murine model of contact hypersensitivity.

Orengedokuto (OGT) is a Kampo prescription that has been used for the treatment of inflammation, hypertension, gastrointestinal disorders, and liver and cerebrovascular diseases. It is also used for the treatment of skin diseases such as urticaria and atopic dermatitis. We previously studied its anti-allergic effects of OGT on the murine model of 2,4,6-trinitrochlorobenzene (TNCB)-induced contact hypersensitivity (CHS) and demonstrated that it significantly suppresses ear swelling in a dose-dependent manner. However, the mechanism underlying this activity remained unknown. Here, we sought to identify the mechanism involved. Using a murine model of TNCB-induced CHS, together with adoptive cell transfer experiments, we found that the anti-allergic effects of OGT may be due to the inhibition of effector T cell activation and not the induction and/or activation of regulatory T cells. Flow cytometry analysis revealed that oral administration of OGT suppressed the increase in CD8+CD44highCD62L+ cell number in draining lymph nodes (dLNs) of mice sensitized with 5% TNCB. Additionally, ex vivo experiments confirmed the suppressive effect of OGT on the activation of effector T cells, as interferon-γ (IFN-γ) production by cultured lymphocytes obtained from 5% TNCB-sensitized mice and stimulated with anti-CD3ε and anti-CD28 monoclonal antibodies was reduced by OGT administration. In conclusion, our finding suggests that OGT exerts anti-allergic effects by regulating the activation of effector T cells involved in inflammatory skin diseases such as atopic dermatitis.

Putative Immunological Functions of Inducible Skin-Associated Lymphoid Tissue in the Context of Mucosa-Associated Lymphoid Tissue.

Acquired immunity is orchestrated in various lymphoid organs, including bone marrow, thymus, spleen, and lymph nodes in humans. However, mucosa-associated lymphoid tissue (MALT) is evolutionally known to be emerged in the oldest vertebrates as an immunological tissue for acquired immunity, much earlier than the advent of lymph nodes which appeared in endotherms. Furthermore, the lymphocytes which developed in MALT are known to circulate within the limited anatomical areas. Thus, MALT is comprehended as not the structure but the immune network dedicated to local immunity. As for the skin, skin-associated lymphoid tissue (SALT) was previously postulated; however, its existence has not been proven. Our group recently showed that aggregations of dendritic cells, M2 macrophages, and high endothelial venules (HEVs) are essential components to activate effector T cells in the murine contact hypersensitivity model and termed it as inducible SALT (iSALT) since it was a transient entity that serves for acquired immunity of the skin. Furthermore, in various human skin diseases, we reported that the ectopic formation of lymphoid follicles that immunohistochemically analogous to MALT and regarded them as human counterparts of iSALT. These data raised the possibility that SALT can exist as an inducible form, namely iSALT, which shares the biological significance of MALT. In this article, we revisit the evolution of immunological organs and the related components among vertebrates to discuss the conserved functions of MALT. Furthermore, we also discuss the putative characteristics and functions of iSALT in the context of the MALT concept.

IRE1 and PERK signaling regulates inflammatory responses in a murine model of contact hypersensitivity.

Contact sensitizers may interfere with correct protein folding. Generation of un-/misfolded proteins can activate the IRE-1 or PERK signaling pathways initiating the unfolded protein response (UPR) and thereby determine inflammatory immune responses. We have analyzed the effect of sensitizers with different potencies on the induction of UPR activation/inhibition and the subsequent generation of a pro-inflammatory micromilieu in vitro as well as the effect of UPR modulation on the inflammatory response in the murine contact hypersensitivity (CHS) in vivo. Semi-quantitative and quantitative PCR, fluorescence microscopy, ELISA, NF-κB activation and translocation assays, DC/keratinocyte co-culture assay, FACS, and in vivo CHS experiments were performed. Sensitizers and irritants activate IRE-1 and PERK in murine and human keratinocytes. Synergistic effects occur after combination of different weak sensitizers / addition of irritants. Moreover, tolerogenic dinitrothiocyanobenzene can be converted into a strong sensitizer by pre-activation of the UPR. Blocking UPR signaling results in decreased NF-κB activation and cytokine production in keratinocytes and in activation marker downregulation in a HaCaT/THP-1 co-culture. Interestingly, not only systemic but also topical application of UPR inhibitors abrogates CHS responses in vivo. These observations highlight an important role of the UPR in determination of the inflammatory response in vitro and in vivo further underlining the importance of tissue stress and damage responses in the development of ACD and provide mechanistically based concepts as a basis for the development of new therapeutic approaches to treat allergic contact dermatitis.

PD-L1 on mast cells suppresses effector CD8+ T-cell activation in the skin in murine contact hypersensitivity

The programmed cell death-1 (PD-1)/programmed death ligand 1 (PD-L1) pathway is known to inhibit the activation of effector CD8+ T cells. However, just how this regulatory pathway is involved in the pathophysiology of CD8+ T-cell-mediated inflammatory skin diseases remains unclear. Our aim was to elucidate the mechanisms by which the PD-1/PD-L1 pathway exerts its regulatory roles in CD8+ T-cell-mediated cutaneous immune responses. PD-L1-deficient (Pdl1-/-) mice were used for the murine contact hypersensitivity model. Inflammatory responses such as IFN-γ production from CD8+ T cells in the skin was evaluated by flow cytometry. Compared with wild-type mice, Pdl1-/- mice exhibited exacerbated ear swelling and increased numbers of IFN-γ+ CD8+ T cells in the skin. Adoptive T-cell transfer experiments revealed the involvement of the PD-1/PD-L1 pathway in the elicitation phase of contact hypersensitivity. Bone marrow chimera experiments showed that PD-L1 on radioresistant cells was responsible for this regulatory pathway. Flow cytometric analysis revealed that among the radioresistant cells in the skin, PD-L1 was most highly expressed on mast cells (MCs) before and after elicitation. Administration of anti-PD-L1 blocking antibody during the elicitation phase significantly enhanced ear swelling responses and increased the number of IFN-γ+CD8+ T cells in the skin of wild-type mice, whereas no significant effects were observed in MC-deficient (WBB6F1/J-KitW/KitW-v/J and C57BL/6-KitW-sh/W-sh) mice. The high level of expression of PD-L1 on human skin MCs was confirmed by database analysis and immunohistochemical analysis. PD-L1 on MCs negatively regulates CD8+ T-cell activation in the skin.

Therapeutic potential of lipids obtained from γ-irradiated PBMCs in dendritic cell-mediated skin inflammation

BackgroundSince numerous pathological conditions are evoked by unwanted dendritic cell (DC) activity, therapeutic agents modulating DC functions are of great medical interest. In regenerative medicine, cellular secretomes have gained increasing attention and valuable immunomodulatory properties have been attributed to the secretome of γ-irradiated peripheral blood mononuclear cells (PBMCs). Potential effects of the PBMC secretome (PBMCsec) on key DC functions have not been elucidated so far. MethodsWe used a hapten-mediated murine model of contact hypersensitivity (CH) to study the effects of PBMCsec on DCs in vivo. Effects of PBMCsec on human DCs were investigated in monocyte-derived DCs (MoDC) and ex vivo skin cultures. DCs were phenotypically characterised by transcriptomics analyses and flow cytometry. DC function was evaluated by cytokine secretion, antigen uptake, PBMC proliferation and T-cell priming. FindingsPBMCsec significantly alleviated tissue inflammation and cellular infiltration in hapten-sensitized mice. We found that PBMCsec abrogated differentiation of MoDCs, indicated by lower expression of classical DC markers CD1a, CD11c and MHC class II molecules. Furthermore, PBMCsec reduced DC maturation, antigen uptake, lipopolysaccharides-induced cytokine secretion, and DC-mediated immune cell proliferation. Moreover, MoDCs differentiated with PBMCsec displayed diminished ability to prime naïve CD4+T-cells into TH1 and TH2 cells. Furthermore, PBMCsec modulated the phenotype of DCs present in the skin in situ. Mechanistically, we identified lipids as the main biomolecule accountable for the observed immunomodulatory effects. InterpretationTogether, our data describe DC-modulatory actions of lipids secreted by stressed PBMCs and suggest PBMCsec as a therapeutic option for treatment of DC-mediated inflammatory skin conditions. FundingThis research project was supported by the Austrian Research Promotion Agency (Vienna, Austria; grant “APOSEC” 862068; 2015–2019) and the Vienna Business Agency (Vienna, Austria; grant “APOSEC to clinic” 2343727).

Pathogenic CD8+ Epidermis-Resident Memory T Cells Displace Dendritic Epidermal T Cells in Allergic Dermatitis

The skin is our interface with the outside world, and consequently it is exposed to a wide range of microbes and allergens. Recent studies have indicated that allergen-specific skin-resident memory T (TRM) cells play a role in allergic contact dermatitis (ACD). However, the composition and dynamics of the epidermal T-cell subsets during ACD are not known. Here we show that exposure of the skin to the experimental contact allergen DNFB results in a displacement of the normally occurring dendritic epidermal T cells (DETC) concomitant with an accumulation of epidermal CD8+CD69+CD103+ TRM cells in mice. By studying knockout mice, we provide evidence that CD8+ T cells are required for the displacement of the DETC and that DETC are not required for recruitment of CD8+ TRM cells to the epidermis following allergen exposure. We demonstrate that the magnitude of the allergic reaction correlates with the number of CD8+ epidermal TRM cells, which again correlates with allergen dose and number of allergen exposures. Finally, in an attempt to elucidate why CD8+ epidermal TRM cells persist in the epidermis, we show that CD8+ epidermal TRM cells have a higher proliferative capability and are bioenergetically more stable, displaying a higher spare respiratory capacity than DETC.

Biological Effects of IL-26 on T Cell–Mediated Skin Inflammation, Including Psoriasis

Psoriasis is a chronic inflammatory skin disease characterized mainly by epidermal hyperplasia, scaling, and erythema; T helper 17 cells have a role in its pathogenesis. Although IL-26, known as a T helper 17 cytokine, is upregulated in psoriatic skin lesions, its precise role is unclear. We investigated the role of IL-26 in the imiquimod-induced psoriasis-like murine model using human IL-26 transgenic mice. Erythema symptoms induced by daily applications of imiquimod increased dramatically in human IL-26 transgenic mice compared with controls. Vascularization and immune cell infiltration were prominent in skin lesions of human IL-26 transgenic mice. Levels of fibroblast growth factor (FGF) 1, FGF2, and FGF7 were significantly upregulated in the skin lesions of imiquimod-treated human IL-26 transgenic mice and psoriasis patients. Invitro analysis demonstrated that FGF1, FGF2, and FGF7 levels were elevated in human keratinocytes and vascular endothelial cells following IL-26 stimulation. Furthermore, IL-26 acted directly on vascular endothelial cells, promoting proliferation and tube formation, possibly through protein kinase B, extracellular signal-regulated kinase, and NF-κB pathways. Moreover, similar effects of IL-26 were observed in the murine contact hypersensitivity model, indicating that these effects are not restricted to psoriasis. Altogether, our data indicate that IL-26 may be a promising therapeutic target in T cell-mediated skin inflammation, including psoriasis.

851 Three hyaluronic acid synthases differently regulate epidermal and dermal hyaluronan production in murine contact hypersensitivity model

851 Three hyaluronic acid synthases differently regulate epidermal and dermal hyaluronan production in murine contact hypersensitivity model

1064 JAK kinase inhibitors efficiaous in models of murine contact hypersensitivity

Murine models of dermal contact dermatitis have been used as preclinical screening tools to select compounds for topical therapy of human inflammatory diseases such as alopecia areata, vitiligo and atopic dermatitis. All of these diseases are known to be driven by JAK3/common gamma chain (gc) dependent cytokines (e.g., IL-4, IL-15), whose signaling is controlled by JAK1 and JAK3 kinases. We have synthesized soft inhibitors of JAK1/3 that are designed for high skin permeability with minimal systemic stability. Soft, topical JAK inhibitors offer the potential to treat patients, including those with mild to moderate disease, for whom systemic JAK kinase inhibitors might not be ideal. These compounds have been tested topically in a murine contact hypersensitivity model. In this model, animals are systemically immunized to the hapten 2,4-dinitrofluorobenzene (DNFB), followed one week later by topical challenge to the ear, resulting in swelling. JAK kinase inhibitors applied prior to the challenge dose of DNFB can inhibit the swelling, if applied in the appropriate vehicle. Swelling was significantly reduced by 50-70%, with P < 0.05 (unpaired T test). Promising molecules are being profiled with in vitro human/pig skin penetration models (Franz Chamber), using multiple formulations. Using these data, appropriate drug concentration and vehicle(s) will be chosen and murine findings are being extended in the minipig DNFB model as the architecture of minipig skin much more closely resembles that of human skin. Details of the histology and cytokine dependence of these models, along with the local and systemic PK of the drugs studied, will be presented. These data will inform progression to the study of human patients with dermatological autoimmune diseases.

Visualization of T Cell-Regulated Monocyte Clusters Mediating Keratinocyte Death in Acquired Cutaneous Immunity

It remains unclear how monocytes are mobilized to amplify inflammatory reactions in T cell-mediated adaptive immunity. Here, we investigate dynamic cellular events in the cascade of inflammatory responses through intravital imaging of a multicolor-labeled murine contact hypersensitivity model. We found that monocytes formed clusters around hair follicles in the contact hypersensitivity model. In this process, effector T cells encountered dendritic cells under regions of monocyte clusters and secreted IFN-γ, which mobilizes CCR2-dependent monocyte interstitial migration and CXCR2-dependent monocyte cluster formation. We showed that hair follicles shaped the inflammatory microenvironment for communication among the monocytes, keratinocytes, and effector T cells. After disrupting the T cell-mobilized monocyte clusters through CXCR2 antagonization, monocyte activation and keratinocyte apoptosis were significantly inhibited. Our study provides a new perspective on effector T cell-regulated monocyte behavior, which amplifies the inflammatory reaction in acquired cutaneous immunity.

JNJ7777120 Ameliorates Inflammatory and Oxidative Manifestations in a Murine Model of Contact Hypersensitivity via Modulation of TLR and Nrf2 Signaling.

JNJ7777120, a histamine H4 receptor antagonist, was shown to be effective in different experimental settings of allergic inflammation, including contact hypersensitivity. Toll-like receptors (TLRs) are thought to function as a link between innate and adaptive immune responses to various haptens. Here, we studied the suppression of TLR signaling as a possible mechanism by which JNJ7777120 exerts its anti-inflammatory effects against the chemical hapten, fluorescein isothiocyanate (FITC). The potential anti-oxidant effect of JNJ7777120 in this model was also examined. Mice subjected to FITC sensitization and challenge showed significantly elevated plasma immunoglobulin E (IgE) level, ear interleukin-4 (IL-4), tumor necrosis factor-alpha (TNF-α), and thiobarbituric acid reactive substance (TBARS) contents as well as increased myeloid differentiation factor 88 (MyD88) gene expression, nuclear factor-kappa B p65 (NF-κB p65), and phospho-p38 mitogen-activated protein kinase (p-p38 MAPK) protein expression. This was accompanied by enhanced ear myeloperoxidase (MPO) and eosinophil peroxidase (EPO) activities as well as diminished glutathione (GSH) content and superoxide dismutase (SOD) activity. JNJ7777120 treatment perceivably reversed these effects, denoting profound anti-inflammatory and anti-oxidant character of JNJ7777120 which was confirmed by its mitigation of FITC-induced pathological changes in mouse ear. JNJ7777120 additionally enhanced the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), providing a novel mechanism by which JNJ7777120 functions as an anti-oxidant in this model. To conclude, JNJ7777120 afforded a remarkable amendment of FITC skin insult by virtue of its anti-inflammatory and anti-oxidant effects; the mechanistic basis of these effects may include modulation of TLR and Nrf2 pathways.

RNA Aptamers Recognizing Murine CCL17 Inhibit T Cell Chemotaxis and Reduce Contact Hypersensitivity InVivo.

The chemokine CCL17, mainly produced by dendritic cells (DCs) in the immune system, is involved in the pathogenesis of various inflammatory diseases. As a ligand of CCR4, CCL17 induces chemotaxis and facilitates T cell-DC interactions. We report the identification of two novel RNA aptamers, which were validated in vitro and in vivo for their capability to neutralize CCL17. Both aptamers efficiently inhibited the directed migration of the CCR4+ lymphoma line BW5147.3 toward CCL17 in a dose-dependent manner. To study the effect of these aptamers in vivo, we used a murine model of contact hypersensitivity. Systemic application of the aptamers significantly prevented ear swelling and T cell infiltration into the ears of sensitized mice after challenge with the contact sensitizer. The results of this proof-of-principle study establish aptamers as potent inhibitors of CCL17-mediated chemotaxis. Potentially, CCL17-specific aptamers may be used therapeutically in humans to treat or prevent allergic and inflammatory diseases.

Ultraviolet Radiation-Induced Immunosuppression: Induction of Regulatory T Cells.

Solar/ultraviolet (UV) radiation exerts a variety of biological effects, including suppression of the immune system. UV-induced immunosuppression is induced by suberythemogenic/physiological UV doses, and it affects primarily T-cell driven immune reactions. Another characteristic feature of UV-induced immunosuppression is its antigen-specificity. This is due to the induction of T cells with suppressive features, called regulatory T cells. Since UV-induced regulatory T cells may harbor therapeutic potential phenotypic and functional characterization of these cells is ongoing. Most of these studies have been performed in the murine model of contact hypersensitivity. In this protocol we describe a method for the UV-induced suppression of the induction of contact hypersensitivity and the adoptive transfer of immune response.

Therapeutic effects of human gingiva-derived mesenchymal stromal cells on murine contact hypersensitivity via prostaglandin E2-EP3 signaling.

BackgroundThe immunomodulatory and anti-inflammatory functions of human gingiva-derived mesenchymal stromal cells (GMSCs) have been demonstrated in contact hypersensitivity (CHS) models; however, their therapeutic effect during the late phase of CHS has been poor.MethodsThe murine CHS model was induced by applying oxazolone to the ears of mice. Mesenchymal stromal cells were applied via two methods (intravenous or local injection) at three time points: 1 day before sensitization, 1 day before challenge, or 1 h after challenge. Prostaglandin E2 (PGE2) and sulprostone were administered subcutaneously 1 h after challenge.ResultsThe application of GMSCs, bone marrow mesenchymal stem cells, and adipose-derived stem cells all effectively suppressed CHS; however, GMSC treatment exhibited the greatest efficacy. Local injection of GMSCs led to a more marked attenuation of CHS compared with intravenous injection, especially during the late phase of CHS, and this manifested as decreased infiltration of inflammatory cells, suppression of the levels of various proinflammatory cytokines, reconstruction of the disrupted Th1/Th2 balance, and upregulation of regulatory T cells in the allergen contact areas. Pretreatment with indomethacin significantly abrogated the GMSC-mediated immunosuppressive effects, while PGE2 application reversed the effects of indomethacin pretreatment of GMSCs. Moreover, GMSC administration promoted the expression of EP3, a prostaglandin E receptor, and the application of sulprostone, an agonist of EP3, significantly attenuated CHS to a similar degree as that of GMSC administration.ConclusionsGMSCs have reproducible and powerful immunomodulatory functions. Local injection of GMSCs is the superior mode for therapeutic application. PGE2–EP3 signaling plays an important role in the immunomodulatory functions of GMSCs in murine CHS.Electronic supplementary materialThe online version of this article (doi:10.1186/s13287-016-0361-9) contains supplementary material, which is available to authorized users.