IL-10 is critical for Th2 responses in a murine model of allergic dermatitis

Cytokines and chemokines skin gene expression in correlation with immune cells in blood and severity in equine insect bite hypersensitivity

Background

Insect bite hypersensitivity (IBH) is the most frequent skin allergy of horses and is highly debilitating, especially in the chronic phase. IBH is caused by IgE-mediated hypersensitivity reactions to culicoides midge bites and an imbalanced immune response that reduces the welfare of affected horses.

Objective

In the present study, we investigated the pathological mechanisms of IBH, aiming to understand the immune cell modulation in acute allergic skin lesions of IBH horses with the goal of finding possible biomarkers for a diagnostic approach to monitor treatment success.

Methods

By qPCR, we quantified the gene expression of cytokines, chemokines, and immune receptors in skin punch biopsies of IBH with different severity levels and healthy horses simultaneously in tandem with the analysis of immune cell counts in the blood.

Results

Our data show an increase in blood eosinophils, monocytes, and basophils with a concomitant, significant increase in associated cytokine, chemokine, and immune cell receptor mRNA expression levels in the lesional skin of IBH horses. Moreover, IL-5Ra, CCR5, IFN-γ, and IL-31Ra were strongly associated with IBH severity, while IL-31 and IL-33 were rather associated with a milder form of IBH. In addition, our data show a strong correlation of basophil cell count in blood with IL-31Ra, IL-5, IL-5Ra, IFN-γ, HRH2, HRH4, CCR3, CCR5, IL-12b, IL-10, IL-1β, and CCL26 mRNA expression in skin punch biopsies of IBH horses.

Conclusion

In summary, several cytokines and chemokines have been found to be associated with disease severity, hence contributing to IBH pathology. These molecules can be used as potential biomarkers to monitor the onset and progression of the disease or even to evaluate and monitor the efficacy of new therapeutic treatments for IBH skin allergy. To our knowledge, this is the first study that investigated immune cells together with a large set of genes related to their biological function, including correlation to disease severity, in a large cohort of healthy and IBH horses.

IL-10 Neutralization Attenuates Mast Cell Responses in a Murine Model of Experimental Food Allergy

IgE-mediated mast cell (MC) activation is a critical component of allergic responses to oral Ags. Several T cell-derived cytokines have been shown to promote MC reactivity, and we recently demonstrated a critical role for the cytokine IL-10 in mediating MC responses during food allergy. In this study, we further validate the role of IL-10 using Ab-mediated IL-10 depletion. IL-10 neutralization significantly attenuated MC responses, leading to decreased MC accumulation and activation, as well as inhibition of MC-mediated symptoms such as allergic diarrhea. This was accompanied by decreased Th2 cytokine gene expression, attenuated systemic T cell responses, and fewer CD4 T cells, B cells, and MCs in the spleen. Our data further confirm the role of IL-10 in driving MC responses and suggest that IL-10-responsive MCs may constitute an important player in allergic responses.

IL-10 Differentially Promotes Mast Cell Responsiveness to IL-33, Resulting in Enhancement of Type 2 Inflammation and Suppression of Neutrophilia

Mast cells (MCs) play critical roles in the establishment of allergic diseases. We recently demonstrated an unexpected, proinflammatory role for IL-10 in regulating MC responses. IL-10 enhanced MC activation and promoted IgE-dependent responses during food allergy. However, whether these effects extend to IgE-independent stimuli is not clear. In this article, we demonstrate that IL-10 plays a critical role in driving IL-33-mediated MC responses. IL-10 stimulation enhanced MC expansion and degranulation, ST2 expression, IL-13 production, and phospho-relA upregulation in IL-33-treated cells while suppressing TNF-α. These effects were partly dependent on endogenous IL-10 and further amplified in MCs coactivated with both IL-33 and IgE/Ag. IL-10's divergent effects also extended in vivo. In a MC-dependent model of IL-33-induced neutrophilia, IL-10 treatment enhanced MC responsiveness, leading to suppression of neutrophils and decreased TNF-α. In contrast, during IL-33-induced type 2 inflammation, IL-10 priming exacerbated MC activity, resulting in MC recruitment to various tissues, enhanced ST2 expression, induction of hypothermia, recruitment of eosinophils, and increased MCPT-1 and IL-13 levels. Our data elucidate an important role for IL-10 as an augmenter of IL-33-mediated MC responses, with implications during both allergic diseases and other MC-dependent disorders. IL-10 induction is routinely used as a prognostic marker of disease improvement. Our data suggest instead that IL-10 can enhance ST2 responsiveness in IL-33-activated MCs, with the potential to both aggravate or suppress disease severity depending on the inflammatory context.

Siglec-F+ neutrophils in the spleen induce immunosuppression following acute infection

Background: The mechanisms underlying the increased mortality of secondary infections during the immunosuppressive phase of sepsis remain elusive. Objectives: We sought to investigate the role of Siglec-F+ neutrophils on splenic T lymphocytes in the immunosuppressed phase of sepsis and on secondary infection in PICS mice, and to elucidate the underlying mechanisms. Methods: We established a mouse model of sepsis-induced immunosuppression followed by secondary infection with LPS or E. coli. The main manifestation of immunosuppression is the functional exhaustion of splenic T lymphocytes. Treg depletion reagent Anti-IL-2, IL-10 blocker Anti-IL-10R, macrophage depletion reagent Liposomes, neutrophil depletion reagent Anti-Ly6G, neutrophil migration inhibitor SB225002, Siglec-F depletion reagent Anti-Siglec-F are all used on PICS mice. The function of neutrophil subsets was investigated by adoptive transplantation and the experiments in vitro. Results: Compared to other organs, we observed a significant reduction in pro-inflammatory cytokines in the spleen, accompanied by a marked increase in IL-10 production, primarily by infiltrating neutrophils. These infiltrating neutrophils in the spleen during the immunosuppressive phase of sepsis undergo phenotypic change in the local microenvironment, exhibiting high expression of neutrophil biomarkers such as Siglec-F, Ly6G, and Siglec-E. Depletion of neutrophils or specifically targeting Siglec-F leads to enhance the function of T lymphocytes and a notable improvement in the survival of mice with secondary infections. Conclusions: We identified Siglec-F+ neutrophils as the primary producers of IL-10, which significantly contributed to T lymphocyte suppression represents a novel finding with potential therapeutic implications.

Actives from the Micro-Immunotherapy Medicine 2LMIREG® Reduce the Expression of Cytokines and Immune-Related Markers Including Interleukin-2 and HLA-II While Modulating Oxidative Stress and Mitochondrial Function

Introduction

Micro-immunotherapy (MI) is a therapeutic option employing low doses (LD) and ultra-low doses (ULD) of cytokines and immune factors to help the organism at modulating the immune responses. In an overpowering inflammatory context, this strategy may support the restoration of the body's homeostasis, as the active ingredients of MI medicines' (MIM) could boost or slow down the physiological functions of the immune cells. The aim of the study is to evaluate for the first time the in vitro anti-inflammatory properties of some actives employed by the MIM of interest in several human immune cell models.

Methods

In the first part of the study, the effects of the actives from the MIM of interest were assessed from a molecular standpoint: the expression of HLA-II, interleukin (IL)-2, and the secretion of several other cytokines were evaluated. In addition, as mitochondrial metabolism is also involved in the inflammatory processes, the second part of the study aimed at assessing the effects of these actives on the mitochondrial reactive oxygen species (ROS) production and on the mitochondrial membrane potential.

Results

We showed that the tested actives decreased the expression of HLA-DR and HLA-DP in IFN-γ-stimulated endothelial cells and in LPS-treated-M1-macrophages. The tested MIM slightly reduced the intracellular expression of IL-2 in CD4+ and CD8+ T-cells isolated from PMA/Iono-stimulated human PBMCs. Additionally, while the secretion of IL-2, IL-10, and IFN-γ was diminished, the treatment increased IL-6, IL-9, and IL-17A, which may correspond to a "Th17-like" secretory pattern. Interestingly, in PMA/Iono-treated PBMCs, we reported that the treatment reduced the ROS production in B-cells. Finally, in PMA/Iono-treated human macrophages, we showed that the treatment slightly protected the cells from early cell death/apoptosis.

Discussion

Overall, these results provide data about the molecular and functional anti-inflammatory effects of several actives contained in the tested MIM in immune-related cells, and their impact on two mitochondria-related processes.

Radiation-Detoxified Form of Endotoxin Effectively Activates Th1 Responses and Attenuates Ragweed-Induced Th2-Type Airway Inflammation in Mice

Urbanization with reduced microbial exposure is associated with an increased burden of asthma and atopic symptoms. Conversely, environmental exposure to endotoxins in childhood can protect against the development of allergies. Our study aimed to investigate whether the renaturation of the indoor environment with aerosolized radiation-detoxified lipopolysaccharide (RD-LPS) has a preventative effect against the development of ragweed-induced Th2-type airway inflammation. To explore this, cages of six-week-old BALB/c mice were treated daily with aerosolized native LPS (N-LPS) or RD-LPS. After a 10-week treatment period, mice were sensitized and challenged with ragweed pollen extract, and inflammatory cell infiltration into the airways was observed. As dendritic cells (DCs) play a crucial role in the polarization of T-cell responses, in our in vitro experiments, the effects of N-LPS and RD-LPS were compared on human monocyte-derived DCs (moDCs). Mice in RD-LPS-rich milieu developed significantly less allergic airway inflammation than mice in N-LPS-rich or common environments. The results of our in vitro experiments demonstrate that RD-LPS-exposed moDCs have a higher Th1-polarizing capacity than moDCs exposed to N-LPS. Consequently, we suppose that the aerosolized, non-toxic RD-LPS applied in early life for the renaturation of urban indoors may be suitable for the prevention of Th2-mediated allergies in childhood.

The dichotomic role of single cytokines: Fine-tuning immune responses

Cytokines are known for their pleiotropic effects. They can be classified by their function as pro-inflammatory, such as tumor necrosis factor (TNF), interleukin (IL) 1 and IL-12, or anti-inflammatory, like IL-10, IL-35 and transforming growth factor β (TGF-β). Though this type of classification is an important simplification for the understanding of the general cytokine's role, it can be misleading. Here, we discuss recent studies that show a dichotomic role of the so-called pro and anti-inflammatory cytokines, highlighting that their function can be dependent on the microenvironment and their concentrations. Furthermore, we discuss how the back-and-forth interplay between cytokines and immunometabolism can influence the dichotomic role of inflammatory responses as an important target to complement cytokine-based therapies.

Alteration of Immunoregulatory Patterns and Survival Advantage of Key Cell Types in Food Allergic Children

All allergic responses to food indicate the failure of immunological tolerance, but it is unclear why cow's milk and egg (CME) allergies resolve more readily than reactivity to peanuts (PN). We sought to identify differences between PN and CME allergies through constitutive immune status and responses to cognate and non-cognate food antigens. Children with confirmed allergy to CME (n = 6) and PN (n = 18) and non-allergic (NA) (n = 8) controls were studied. Constitutive secretion of cytokines was tested in plasma and unstimulated mononuclear cell (PBMNC) cultures. Blood dendritic cell (DC) subsets were analyzed alongside changes in phenotypes and soluble molecules in allergen-stimulated MNC cultures with or without cytokine neutralization. We observed that in allergic children, constitutively high plasma levels IL-1β, IL-2, IL-4, IL-5 and IL-10 but less IL-12p70 than in non-allergic children was accompanied by the spontaneous secretion of sCD23, IL-1β, IL-2, IL-4, IL-5, IL-10, IL-12p70, IFN-γ and TNF-α in MNC cultures. Furthermore, blood DC subset counts differed in food allergy. Antigen-presenting cell phenotypic abnormalities were accompanied by higher B and T cell percentages with more Bcl-2 within CD69+ subsets. Cells were generally refractory to antigenic stimulation in vitro, but IL-4 neutralization led to CD152 downregulation by CD4+ T cells from PN allergic children responding to PN allergens. Canonical discriminant analyses segregated non-allergic and allergic children by their cytokine secretion patterns, revealing differences and areas of overlap between PN and CME allergies. Despite an absence of recent allergen exposure, indication of in vivo activation, in vitro responses independent of challenging antigen and the presence of unusual costimulatory molecules suggest dysregulated immunity in food allergy. Most importantly, higher Bcl-2 content within key effector cells implies survival advantage with the potential to mount abnormal responses that may give rise to the manifestations of allergy. Here, we put forward the hypothesis that the lack of apoptosis of key immune cell types might be central to the development of food allergic reactions.

Intradermal Delivery of Naked mRNA Vaccines via Iontophoresis

Messenger RNA (mRNA) vaccines against infectious diseases and for anticancer immunotherapy have garnered considerable attention. Currently, mRNA vaccines encapsulated in lipid nanoparticles are administrated via intramuscular injection using a needle. However, such administration is associated with pain, needle phobia, and lack of patient compliance. Furthermore, side effects such as fever and anaphylaxis associated with the lipid nanoparticle components are also serious problems. Therefore, noninvasive, painless administration of mRNA vaccines that do not contain other problematic components is highly desirable. Antigen-presenting cells reside in the epidermis and dermis, making the skin an attractive vaccination site. Iontophoresis (ItP) uses weak electric current applied to the skin surface and offers a noninvasive permeation technology that enables intradermal delivery of hydrophilic and ionic substances. ItP-mediated intradermal delivery of biological macromolecules has also been studied. Herein, we review the literature on the use of ItP technology for intradermal delivery of naked mRNA vaccines which is expected to overcome the challenges associated with mRNA vaccination. In addition to the physical mechanism, we discuss novel biological mechanisms of iontophoresis, particularly ItP-mediated opening of the skin barriers and the intracellular uptake pathway, and how the combined mechanisms can allow for effective intradermal delivery of mRNA vaccines.

B-cell-derived IL-10 promotes allergic sensitization in asthma regulated by Bcl-3

Aeroallergen sensitization, mainly mediated by lung epithelium and dendritic cells (DCs), is integral to allergic asthma pathogenesis and progression. IL-10 has a dual role in immune responses, as it inhibits myeloid cell activation but promotes B-cell responses and epithelial cell proliferation. Here, we report a proinflammatory function of B-cell-derived IL-10 modulated by Bcl-3 in allergic asthma. Specifically, Bcl-3-/- mice showed elevated IL-10 levels and were found to be highly vulnerable to allergic asthma induced by house dust mites (HDMs). IL-10 had a positive correlation with the levels of the DC chemoattractant CCL-20 in HDM-sensitized mice and in patients with asthma and induced a selective increase in CCL-20 production by mouse lung epithelial cells. Blockade of IL-10 or IL-10 receptors during sensitization dampened both HDM-induced sensitization and asthma development. IL-10 levels peaked 4 h post sensitization with HDM and IL-10 was primarily produced by B cells under Bcl-3-Blimp-1-Bcl-6 regulation. Mice lacking B-cell-derived IL-10 displayed decreased lung epithelial CCL-20 production and diminished DC recruitment to the lungs upon HDM sensitization, thereby demonstrating resistance to HDM-induced asthma. Moreover, responses to HDM stimulation in Bcl-3-/- mice lacking B-cell-derived IL-10 were comparable to those in Bcl-3+/+ mice. The results revealed an unexpected role of B-cell-derived IL-10 in promoting allergic sensitization and demonstrated that Bcl-3 prevents HDM-induced asthma by inhibiting B-cell-derived IL-10 production. Thus, targeting the Bcl-3/IL-10 axis to inhibit allergic sensitization is a promising approach for treating allergic asthma. IL-10 is released rapidly from lung plasma cells under Bcl-3-Blimp-1-Bcl-6 regulation upon house dust mite exposure and amplifies lung epithelial cell (EC)-derived CCL-20 production and subsequent dendritic cell (DC) recruitment to promote allergic sensitization in asthma.

Regulation of T Helper Cell Type 2 Immune Response by Controlling Beta-2 Adrenergic Receptor in Dendritic Cells of Patients with Allergic Rhinitis

INTRODUCTION

Allergic diseases are mediated by T helper cell type 2 (Th2) cells, which are differentiated by dendritic cells (DCs). Recently, it was reported that cAMP concentration in DCs is important for inducing allergic responses. However, the regulatory function of cAMP in DCs in Th2 immune responses is unclear. It was hypothesized that the regulation of G protein-coupled receptors (GPCRs) to increase cAMP levels in DCs would reduce Th2 immune responses.

METHODS

Human DCs from patients with allergic rhinitis (AR) and from healthy controls were subjected to next-generation sequencing (NGS) to identify potential GPCR. To investigate the functions of GPCR agonists, the in vitro co-culture experiment that THP-1 cells were differentiated into DCs and cultured with human CD4+ T-cells and an AR animal in vivo model were used.

RESULTS

Among the GPCRs, the beta-2 adrenergic receptor (ADRB2) of allergic DCs was significantly increased by NGS analysis. The expression of ADRB2 was also increased in Der p 1-treated DCs, which was reduced by treatment with the ADRB2 agonist salbutamol. Salbutamol treatment induced cAMP production in THP-1 derived DCs. In an in vitro co-culture experiment, salbutamol-treated DCs reduced the secretion of Th2 cytokine. In an in vivo AR animal experiment, salbutamol-administered mice showed reduced allergic behavior and Th2 cytokine expression in the nasal mucosa.

CONCLUSIONS

The regulation of ADRB2 with salbutamol alleviated the allergic response in vitro DC-T cell co-culture and in vivo AR animal models, suggesting that ADRB2 is a therapeutic target for AR and that ADRB2 agonists may be a promising medication for AR.

Obesity-induced dysregulation of skin-resident PPARγ+ Treg cells promotes IL-17A-mediated psoriatic inflammation

Obesity is a major risk factor for psoriasis, but how obesity disrupts the regulatory mechanisms that keep skin inflammation in check is unclear. Here, we found that skin was enriched with a unique population of CD4+Foxp3+ regulatory T (Treg) cells expressing the nuclear receptor peroxisome proliferation-activated receptor gamma (PPARγ). PPARγ drove a distinctive transcriptional program and functional suppression of IL-17A+ γδ T cell-mediated psoriatic inflammation. Diet-induced obesity, however, resulted in a reduction of PPARγ+ skin Treg cells and a corresponding loss of control over IL-17A+ γδ T cell-mediated inflammation. Mechanistically, PPARγ+ skin Treg cells preferentially took up elevated levels of long-chain free fatty acids in obese mice, which led to cellular lipotoxicity, oxidative stress, and mitochondrial dysfunction. Harnessing the anti-inflammatory properties of these PPARγ+ skin Treg cells could have therapeutic potential for obesity-associated inflammatory skin diseases.

Th1 promotes M1 polarization of intestinal macrophages to regulate colitis-related mucosal barrier damage

This work aimed to investigate the role of helper T cell 1 (Th1) in chronic colitis and its immunoregulatory mechanism. The proportions of Th1 and Th2, and the levels of related cytokines in tissues from patients with inflammatory bowel disease (IBD; ulcerative colitis+Crohn's disease, UC+CD) were detected. DSS was used to induce the mouse model of IBD; thereafter, Th1 cells were induced in vitro and amplified before they were injected intraperitoneally. Later, the changes in life state and body weight of mice were observed, the proportion of M1 macrophages in mucosal tissues and mucosal barrier damage were detected. After treatment with macrophage scavenging agent (Clodronate Liposomes, CLL), the influence of Th1 on IBD mice was observed. Then, the intestinal macrophages were co-cultured with Th1 in vitro to observe the influence of Th1 on the polarization of intestinal macrophages. Besides, cells were treated with the STAT3 inhibitor to further detect the macrophage polarization level. Intestinal macrophages were later co-cultured with intestinal epithelial cells to observe the degree of epithelial cell injury. The Th1 proportions in intestinal tissues of UC and CD patients were higher than those in healthy subjects, but the difference in Th2 proportion was not significant. In the IBD mouse model, Th1 induced the M1 polarization of macrophages, aggravated the intestinal inflammatory response, and resulted in the increased mucosal barrier permeability. Pretreatment with CLL antagonized the effect of Th1 cells, reduced the intestinal tissue inflammatory response and mucosal barrier permeability.

Phenotypic, functional and plasticity features of human PBMCs induced by venom secreted PLA2s

Bothrops venom contains a high amount of secreted phospholipase A₂ (sPLA₂s) enzymes responsible for the inflammatory reaction and activation of leukocytes in cases of envenoming. PLA₂s are proteins that have enzymatic activity and can hydrolyze phospholipids at the sn-2 position, thereby releasing fatty acids and lysophospholipids precursors of eicosanoids, which are significant mediators of inflammatory conditions. Whether these enzymes have a role in the activation and function of peripheral blood mononuclear cells (PBMCs) is not known. Here we show for the first time how two secreted PLA₂s (BthTX-I and BthTX-II) isolated from the venom of Bothrops jararacussu affect the function and polarization of PBMCs. Neither BthTX-I nor BthTX-II exhibited significant cytotoxicity to isolated PBMCs compared with the control at any of the time points studied. RT-qPCR and enzyme-linked immunosorbent assays were used to determine changes in gene expression and the release of pro-inflammatory (TNF-α, IL-6, and IL-12) and anti-inflammatory (TGF-β and IL-10) cytokines, respectively, during the cell differentiation process. Lipid droplets formation and phagocytosis were also investigated. Monocytes/macrophages were labeled with anti-CD14, -CD163, and -CD206 antibodies to assay cell polarization. Both toxins caused a heterogeneous morphology (M1 and M2) on days 1 and 7 based on immunofluorescence analysis, revealing the considerable flexibility of these cells even in the presence of typical polarization stimuli. Thus, these findings indicate that the two sPLA₂s trigger both immune response profiles in PBMCs indicating a significant degree of cell plasticity, which may be crucial for understanding the consequences of snake envenoming.

The synergistic and enhancive effects of IL-6 and M-CSF to expand and differentiate functional dendritic cells from human monocytes under serum-free condition

BACKGROUND

Dendritic cells (DCs) are differentiated from monocytes, and have a strong ability to perform phagocytosis, present antigens and activate T cell immune response. Therefore, DCs are one of the key factors in fighting cancer in immunotherapy, and it is an important issue to develop a serum-free system for DC differentiation and expansion in vitro for clinical application.

RESULTS

In this study, IL-6 and M-CSF were determined and a concentration combination of cytokines was optimized to develop an optimal DC serum-free differentiation medium (SF-DC Optimal) that can effectively differentiate CD14⁺ monocytes into CD40⁺CD209⁺ DCs. After differentiation, the morphology, growth kinetics, surface antigen expression, phagocytosis ability, cytokine secretion, mixed lymphocyte reaction and stimulation for maturation of the differentiated DCs were checked and confirmed. Importantly, this research is the first report finding that the addition an extra low concentration of IL-6 and M-CSF exhibited a synergistic effect with GM-CSF and IL-4 to generate higher numbers and more fully functional DCs than the addition of GM-CSF and IL-4 only under serum-free condition.

CONCLUSION

A large number of functional DCs can be generated by using SF-DC Optimal medium and provide an alternative source of DCs for related basic research and clinical applications.

How an Immune-Factor-Based Formulation of Micro-Immunotherapy Could Interfere with the Physiological Processes Involved in the Atopic March

Allergic diseases consist of improper inflammatory reactions to antigens and are currently an important healthcare concern, especially considering their increasing worldwide development in recent decades. The "atopic march" defines the paradigm of allergic diseases occurring in chronological order and displaying specific spatial manifestations, as they usually start as atopic dermatitis (AD) and food allergies during infancy and progressively evolve into allergic asthma (AA) and allergic rhinitis (AR) or rhino-conjunctivitis in childhood. Many immune cell subtypes and inflammatory factors are involved in these hypersensitivity reactions. In particular, the T helpers 2 (Th2) subset, through its cytokine signatures made of interleukins (ILs), such as IL-4, IL-5, IL-10, and IL-13, as well as mast cells and their related histamine pathways, contribute greatly to the perpetuation and evolution of the atopic march. By providing low doses (LD) and ultra-low doses (ULD) of ILs and immune factors to the body, micro-immunotherapy (MI) constitutes an interesting therapeutic strategy for the management of the atopic march and its symptoms. One of the aims of this review is to shed light on the current concept of the atopic march and the underlying immune reactions occurring during the IgE-mediated responses. Moreover, the different classes of traditional and innovative treatments employed in allergic diseases will also be discussed, with a special emphasis on the potential benefits of the MI medicine 2LALERG^® formulation in this context.

Effect of Sopoongsan on Skin Inflammation and Hyperlocomotion in Socially Isolated Mice with Atopic Dermatitis

Psychological stress is a major exacerbating factor of atopic dermatitis (AD), a chronic inflammatory skin disease. Sopoongsan (SPS), a traditional herbal formula, has been indicated for the treatment of various skin disorders, including AD. This study investigated the effects of SPS on a 2,4-dinitrochlorobenzene- (DNCB-) induced AD mice model exposed to social isolation (SI) stress. The severity of the AD symptoms and behavioral abnormalities was evaluated. SPS reduced the clinical skin score as evaluated with the SCORing Atopic Dermatitis (SCORAD) index and suppressed the cutaneous infiltration of T-lymphocyte cells, mast cells, and eosinophils in SI-AD mice. The SPS treatment decreased the total distance and mean speed and increased resting time in the open field test (OFT) for these mice. In addition, the time spent in the social zone in the social interaction test also improved when SPS treatment was given. The levels of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in the prefrontal cortex (PFC) in the SI-AD mice were reduced by the oral administration of SPS. HaCaT and BV2 cells were used for the in vitro experiments. The pretreatment with SPS reduced the protein levels of the thymus and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC) in the HaCaT cells stimulated with TNF-α and interferon-gamma (IFN-γ) (TI). SPS also suppressed TNF-α and IL-6 secretion in lipopolysaccharide- (LPS-) stimulated BV2 cells. These results imply that SPS could be a promising candidate for the treatment of AD in patients under stress conditions and at risk of exacerbation.

Single-dose AAV vector gene immunotherapy to treat food allergy

Immunotherapies for patients with food allergy have shown some success in limiting allergic responses. However, these approaches require lengthy protocols with repeated allergen dosing and patients can relapse following discontinuation of treatment. The purpose of this study was to test if a single dose of an adeno-associated virus (AAV) vector can safely prevent and treat egg allergy in a mouse model. AAV vectors expressing ovalbumin (OVA) under an ubiquitous or liver-specific promoter were injected prior to or after epicutaneous sensitization with OVA. Mice treated with either AAV8-OVA vector were completely protected from allergy sensitization. These animals had a significant reduction in anaphylaxis mediated by a reduction in OVA-specific IgE titers. In mice with established OVA allergy, allergic responses were mitigated only in mice treated with an AAV8-OVA vector expressing OVA from an ubiquitous promoter. In conclusion, an AAV vector with a liver-specific promoter was more effective for allergy prevention, but higher OVA levels were necessary for reducing symptoms in preexisting allergy. Overall, our AAV gene immunotherapy resulted in an expansion of OVA-specific FoxP3⁺ CD4⁺ T cells, an increase in the regulatory cytokine IL-10, and a reduction in the IgE promoting cytokine IL-13.

The kinase p38α functions in dendritic cells to regulate Th2-cell differentiation and allergic inflammation

Dendritic cells (DCs) play a critical role in controlling T helper 2 (Th2) cell-dependent diseases, but the signaling mechanism that triggers this function is not fully understood. We showed that p38α activity in DCs was decreased upon HDM stimulation and dynamically regulated by both extrinsic signals and Th2-instructive cytokines. p38α-specific deletion in cDC1s but not in cDC2s or macrophages promoted Th2 responses under HDM stimulation. Further study showed that p38α in cDC1s regulated Th2-cell differentiation by modulating the MK2−c-FOS−IL-12 axis. Importantly, crosstalk between p38α-dependent DCs and Th2 cells occurred during the sensitization phase, not the effector phase, and was conserved between mice and humans. Our results identify p38α signaling as a central pathway in DCs that integrates allergic and parasitic instructive signals with Th2-instructive cytokines from the microenvironment to regulate Th2-cell differentiation and function, and this finding may offer a novel strategy for the treatment of allergic diseases and parasitic infection.

Tissue-based IL-10 signalling in helminth infection limits IFNγ expression and promotes the intestinal Th2 response

Type 2 immunity is activated in response to both allergens and helminth infection. It can be detrimental or beneficial, and there is a pressing need to better understand its regulation. The immunosuppressive cytokine IL-10 is known as a T helper 2 (Th2) effector molecule, but it is currently unclear whether IL-10 dampens or promotes Th2 differentiation during infection. Here we show that helminth infection in mice elicits IL-10 expression in both the intestinal lamina propria and the draining mesenteric lymph node, with higher expression in the infected tissue. In vitro, exogenous IL-10 enhanced Th2 differentiation in isolated CD4+ T cells, increasing expression of GATA3 and production of IL-5 and IL-13. The ability of IL-10 to amplify the Th2 response coincided with its suppression of IFNγ expression and in vivo we found that, in intestinal helminth infection, IL-10 receptor expression was higher on Th1 cells in the small intestine than on Th2 cells in the same tissue, or on any Th cell in the draining lymph node. In vivo blockade of IL-10 signalling during helminth infection resulted in an expansion of IFNγ+ and Tbet+ Th1 cells in the small intestine and a coincident decrease in IL-13, IL-5 and GATA3 expression by intestinal T cells. These changes in Th2 cytokines correlated with reduced expression of type 2 effector molecules, such as RELMα, and increased parasite egg production. Together our data indicate that IL-10 signalling promotes Th2 differentiation during helminth infection at least in part by regulating competing Th1 cells in the infected tissue.

Anti-Allergic Effects of Fermented Red Ginseng Marc on 2,4-Dinitrochlorobenzene-Induced Atopic Dermatitis-like Mice Model

Atopic dermatitis (AD) is a chronic and allergic skin disease; however, there is no cure for the disease. Red ginseng is well known to have anti-AD potential, while red ginseng marc (RGM) remaining after ginseng extraction is regarded as useless and discarded. However, it has recently been reported that RGM, particularly fermented RGM (fRGM), still contains bioactive properties. Thus, the anti-allergic effects of fRGM were examined in a 2,4-dinitrochlorobenzene-induced AD-like mice model. The model was topically treated with distilled water (control), dexamethasone, or fRGM for six weeks. Treatments of fRGM alleviated skin lesions and reduced serum IgE levels, compared with the control. The fRGM also reduced skin levels of lipid peroxidation and superoxide anion; however, it increased glutathione contents, with downregulated gene expression for inflammatory mediators. Histopathological analyses demonstrated that fRGM suppressed epidermal thickening, collagen deposition, and inflammatory cell and mast cell infiltration, which involved anti-inflammatory, antioxidant, and anti-apoptotic effects. Further, fRGM suppressed hypertrophic changes and inflammatory responses in the spleen and lymph nodes. The beneficial effects were observed in the dexamethasone and fRGM groups; however, the antioxidant effects were evident only in the fRGM treatments. These results provide useful information for developing fRGM as a therapeutic source for AD.

Inflammasome Contribution to the Activation of Th1, Th2, and Th17 Immune Responses

Inflammasomes are cytosolic polyprotein complexes formed in response to various external and internal stimuli, including viral and bacterial antigens. The main product of the inflammasome is active caspase 1 which proteolytically cleaves, releasing functional interleukin-1 beta (IL-1β) and interleukin-18 (IL-18). These cytokines play a central role in shaping immune response to pathogens. In this review, we will focus on the mechanisms of inflammasome activation, as well as their role in development of Th1, Th2, and Th17 lymphocytes. The contribution of cytokines IL-1β, IL-18, and IL-33, products of activated inflammasomes, are summarized. Additionally, the role of cytokines released from tissue cells in promoting differentiation of lymphocyte populations is discussed.

Immunological effects of adjuvanted low-dose allergoid allergen-specific immunotherapy in experimental murine house dust mite allergy

BACKGROUND

Native allergen extracts or chemically modified allergoids are routinely used to induce allergen tolerance in allergen-specific immunotherapy (AIT), although mechanistic side-by-side studies are rare. It is paramount to balance optimal dose and allergenicity to achieve efficacy warranting safety. AIT safety and efficacy could be addressed by allergen dose reduction and/or use of allergoids and immunostimulatory adjuvants, respectively. In this study, immunological effects of experimental house dust mite (HDM) AIT were investigated applying high-dose HDM extract and low-dose HDM allergoids with and without the adjuvants microcrystalline tyrosine (MCT) and monophosphoryl lipid A (MPL) in a murine model of HDM allergy.

METHODS

Cellular, humoral, and clinical effects of the different AIT strategies were assessed applying a new experimental AIT model of murine allergic asthma based on physiological, adjuvant-free intranasal sensitization followed by subcutaneous AIT.

RESULTS

While low-dose allergoid and high-dose extract AIT demonstrated comparable potency to suppress allergic airway inflammation and Th2-type cytokine secretion of lung-resident lymphocytes and draining lymph node cells, low-dose allergoid AIT was less effective in inducing a potentially protective IgG1 response. Combining low-dose allergoid AIT with MCT or MCT and dose-adjusted MPL promoted Th1-inducing mechanisms and robust B-cell activation counterbalancing the allergic Th2 immune response.

CONCLUSION

Low allergen doses induce cellular and humoral mechanisms counteracting Th2-driven inflammation by using allergoids and dose-adjusted adjuvants. In light of safety and efficacy improvement, future therapeutic approaches may use low-dose allergoid strategies to drive cellular tolerance and adjuvants to modulate humoral responses.

Interleukin-10 improves stroke outcome by controlling the detrimental Interleukin-17A response

Background

Lymphocytes have dichotomous functions in ischemic stroke. Regulatory T cells are protective, while IL-17A from innate lymphocytes promotes the infarct growth. With recent advances of T cell-subtype specific transgenic mouse models it now has become possible to study the complex interplay of T cell subpopulations in ischemic stroke.

Methods

In a murine model of experimental stroke we analyzed the effects of IL-10 on the functional outcome for up to 14 days post-ischemia and defined the source of IL-10 in ischemic brains based on immunohistochemistry, flow cytometry, and bone-marrow chimeric mice. We used neutralizing IL-17A antibodies, intrathecal IL-10 injections, and transgenic mouse models which harbor a deletion of the IL-10R on distinct T cell subpopulations to further explore the interplay between IL-10 and IL-17A pathways in the ischemic brain.

Results

We demonstrate that IL-10 deficient mice exhibit significantly increased infarct sizes on days 3 and 7 and enlarged brain atrophy and impaired neurological outcome on day 14 following tMCAO. In ischemic brains IL-10 producing immune cells included regulatory T cells, macrophages, and microglia. Neutralization of IL-17A following stroke reversed the worse outcome in IL-10 deficient mice and intracerebral treatment with recombinant IL-10 revealed that IL-10 controlled IL-17A positive lymphocytes in ischemic brains. Importantly, IL-10 acted differentially on αβ and γδ T cells. IL-17A producing CD4⁺ αβ T cells were directly controlled via their IL-10-receptor (IL-10R), whereas IL-10 by itself had no direct effect on the IL-17A production in γδ T cells. The control of the IL-17A production in γδ T cells depended on an intact IL10R signaling in regulatory T cells (Tregs).

Conclusions

Taken together, our data indicate a key function of IL-10 in restricting the detrimental IL-17A-signaling in stroke and further supports that IL-17A is a therapeutic opportunity for stroke treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-021-02316-7.

Histamine Increases Th2 Cytokine-Induced CCL18 Expression in Human M2 Macrophages

The chemokine CCL18 is produced in cells of the myelomonocytic lineage and represents one of the most highly expressed chemokines in lesional skin and serum of atopic dermatitis patients. We investigated the role of histamine in CCL18 production in human monocyte-derived M2 macrophages differentiated in the presence of M-CSF and activated with IL-4, IL-13 or with IL-10. Since expression and regulation of histamine H1 receptor (H1R), H2R and H4R by IL-4 and IL-13 on human M2 macrophages were described, we analyzed expression of the histamine receptors in response to IL-10 stimulation by quantitative RT-PCR. IL-10 upregulated H2R and downregulated H4R mRNA expression by trend in M2 macrophages. IL-10, but in a more pronounced manner, IL-4 and IL-13, also upregulated CCL18. Histamine increased the cytokine-induced upregulation of CCL18 mRNA expression by stimulating the H2R. This effect was stronger in IL-10-stimulated M2 macrophages where the upregulation of CCL18 was confirmed at the protein level by ELISA using selective histamine receptor agonist and antagonists. The histamine-induced CCL18 upregulation in IL-10-activated M2 macrophages was almost similar in cells obtained from atopic dermatitis patients compared to cells from healthy control persons. In summary, our data stress a new function of histamine showing upregulation of the Th2 cells attracting chemokine CCL18 in human, activated M2 macrophages. This may have an impact on the course of atopic dermatitis and for the development of new therapeutic interventions.

Na+/H+ Exchanger Regulatory Factor 1 Mediates the Pathogenesis of Airway Inflammation in a Murine Model of House Dust Mite-Induced Asthma

Na⁺/H⁺ exchanger regulatory factor 1 (NHERF1), a class I PDZ-binding protein, regulates G protein-coupled receptor signaling in some cell types. NHERF1 also functions as a scaffolding protein and activates non-G protein-coupled receptor signaling pathways, thereby contributing to the pathogenesis of various diseases. Although we have previously shown that NHERF1 regulates mast cell functions, there is little information regarding the role of NHERF1 in other immune cells. How NHERF1 regulates the pathogenesis of allergic disease such as asthma also remains unknown. In the current study, we show that NHERF1 promotes allergic airway inflammation in a house dust mite extract (HDME)-induced mouse model of asthma. Specifically, HDME-specific serum IgE levels, airway leukocyte numbers, and goblet cell hyperplasia were reduced in NHERF1^+/- mice as compared with NHERF1^+/+ mice. Interestingly, the gene expression of inflammatory (IL-17a, IL-25, and IL-33) as well as T helper 2 (Th2) cytokines (IL-4, IL-5, and IL-13) and several chemokines that recruit eosinophils, neutrophils, and lymphocytes were also decreased in the lungs of NHERF1^+/- mice exposed to HDME. Consistent with these observations, microRNAs regulating mucus production, inflammation, Th2 effector functions, and IL-13 expression were increased in the lungs of HDME-treated NHERF1^+/- mice. Overall, our studies reveal a unique role for NHERF1 in regulating asthma pathogenesis, and further elucidation of the mechanisms through which NHERF1 modulates allergic inflammation will lead to the development of new therapeutic strategies for asthma.

Blimp-1 is essential for allergen-induced asthma and Th2 cell development in the lung

A Th2 immune response is central to allergic airway inflammation, which afflicts millions worldwide. However, the mechanisms that augment GATA3 expression in an antigen-primed developing Th2 cell are not well understood. Here, we describe an unexpected role for Blimp-1, a transcriptional repressor that constrains autoimmunity, as an upstream promoter of GATA3 expression that is critical for Th2 cell development in the lung to inhaled but not systemically delivered allergens but is dispensable for T_FH function and IgE production. Mechanistically, Blimp-1 acts through Bcl6, leading to increased GATA3 expression in lung Th2 cells. Surprisingly, the anti-inflammatory cytokine IL-10, but not the pro-inflammatory cytokines IL-6 or IL-21, is required via STAT3 activation to up-regulate Blimp-1 and promote Th2 cell development. These data reveal a hitherto unappreciated role for an IL-10–STAT3–Blimp-1 circuit as an initiator of an inflammatory Th2 response in the lung to allergens. Thus, Blimp-1 in a context-dependent fashion can drive inflammation by promoting rather than terminating effector T cell responses.

Interleukin 10: the critical role of a pleiotropic cytokine in food allergy

Despite advances in research, the pathophysiology of food allergy has not yet been fully elucidated. IL-10 has both a pro- and anti-inflammatory effect on the development of food allergy and in order to understand its different immune-modulatory effects the factors that influence the inflammatory microenvironment need to be taken into account. Specific single nucleotide polymorphisms of the IL-10 gene seem to confer an increased risk of developing food allergy, but to date there is a substantial lack of genome- wide association studies regarding the genetic and epigenetic underpinnings of the disease. Special interest has been drawn to the development of allergen-specific regulatory CD4+CD25+ T-cells secreting IL-10 in the immunotherapy of allergic diseases. In addition, a distinct population of human tolerogenic dendritic cells (DC), DC-10 seems to hold great potential and could potentially serve as a therapeutic tool to improve the management of food allergy.

Ribonuclease T2 from Aspergillus fumigatus promotes T helper type 2 responses through M2 polarization of macrophages

Allergic bronchopulmonary aspergillosis (ABPA) is an allergic immunological response to Aspergillus fumigatus (Af) exposure, which induces a strong T helper 2 (Th2) response via mechanisms that have yet to be elucidated. The aim of the present study was to investigate the hypothesis that T2 ribonuclease from Af (Af RNASET2) induces M2‑type macrophage polarization to produce a T helper 2 (Th2) immune response. Recombinant Af RNASET2 (rAf RNASET2) was expressed and purified in a prokaryotic pET system and BALB/c mice were immunized with rAf RNASET2 for in vivo analyses. Expression levels of M2 polarization factors were evaluated in RAW264.7 macrophages treated with rAf RNASET2 in vitro using flow cytometry, reverse transcription‑quantitative PCR, and western blot analysis. The results predicted that the mature Af RNASET2 protein (382 amino acids; GenBank no. MN593022) contained two conserved amino acid sequence (CAS) domains, termed CAS‑1 and CAS‑2, which are also characteristic of the RNASET2 family proteins. The protein expression levels of the Th2‑related cytokines interleukin (IL)‑4, IL‑10, and IL‑13 were upregulated in mice immunized with rAf RNASET2. RAW264.7 macrophages treated with rAf RNASET2 showed increased mRNA expression levels of M2 factors [arginase 1, Il‑10, and Il‑13]; however, there was no difference in cells treated with rAf RNASET2 that had been inactivated with a ribonuclease inhibitor (RNasin). The protein expression levels of IL‑10 in macrophage culture supernatant were also increased following stimulation with rAf RNASET2. In addition, rAf RNASET2 upregulated the expression of phosphorylated mitogen activated protein kinases (MAPKs) in RAW264.7 cells, whereas MAPK inhibitors attenuated rAf RNASET2‑induced IL‑10 expression in RAW264.7 cells. In conclusion, the present study reveals that high rAf RNASET2 activity is required for rAf RNASET2‑induced M2 polarization of macrophages and suggests an important immune regulatory role for Af RNASET2 in ABPA pathogenesis.

Mechanisms of Wheat Allergenicity in Mice: Comparison of Adjuvant-Free vs. Alum-Adjuvant Models

Wheat protein is considered a major type of food allergen in many countries including the USA. The mechanisms of allergenicity of wheat proteins are not well understood at present. Both adjuvant-based and adjuvant-free mouse models are reported for this food allergy. However, it is unclear whether the mechanisms underlying wheat allergenicity in these two types of models are similar or different. Therefore, we compared the molecular mechanisms in a novel adjuvant-free (AF) model vs. a conventional alum-adjuvant (AA) model of wheat allergy using salt-soluble wheat protein (SSWP). In the AF model, Balb/cJ mice were sensitized with SSWP via skin exposure. In the AA model, mice were sensitized by an intraperitoneal injection of SSWP with alum. In both models, allergic reactions were elicited using an identical protocol. Robust IgE as well as mucosal mast cell protein-1 responses were elicited similarly in both models. However, an analysis of the spleen immune markers identified strikingly different molecular activation patterns in these two models. Furthermore, a number of immune markers associated with intrinsic allergenicity were also identified in both models. Since the AF model uses skin exposure without an adjuvant, the mechanisms in the AF model may more closely simulate the human wheat allergenicity mechanisms from skin exposure in occupational settings such as in the baking industry.

The antipsychotic drug pimozide inhibits IgE-mediated mast cell degranulation and migration

BACKGROUND

Mast cells (MCs) mediate a key role in allergic diseases. Detailed studies of how the neuroleptic drug pimozide affects MC activity are lacking. The aim of this study was to investigate pimozide inhibition of immunoglobulin E (IgE)-mediated MC activation and MC-mediated allergic responses.

METHOD

MCs were stimulated with anti-dinitrophenyl (DNP) IgE antibodies and DNP-horse serum albumin (HSA) antigen (Ag), and anti-allergic pimozide effects were detected by measuring β-hexosaminidase levels. Morphological changes were observed histologically. In vivo pimozide effects were assessed in passive cutaneous anaphylaxis (PCA) and ovalbumin (OVA)-sensitized active systemic anaphylaxis mouse (ASA) model experiments. Levels of phosphorylated (p-) SYK (spleen tyrosine kinase) and MAPKs (mitogen-activated protein kinases) were detected in western blots.

RESULTS

We found that pimozide inhibited MC degranulation, reduced MC release of β-hexosaminidase dose-dependently in activated RBL-2H3 (IC₅₀: 13.52 μM) and bone marrow derived MC (BMMC) (IC₅₀: 42.42 μM), and reduced MC morphological changes. The IgE/Ag-induced migration effect was suppressed by pimozide treatment dose-dependently. Pimozide down-regulated IgE/Ag-induced phosphorylation of SYK and MAPKs in activated MCs. Moreover, pimozide attenuated allergic reactions in PCA and ASA model mice, and decreased MC populations among splenic cells.

CONCLUSIONS

The antipsychotic drug pimozide can suppress IgE-mediated MC activation in vitro and in vivo and should be considered for repurposing to suppress MC-mediated diseases.

Molecular switches for regulating the differentiation of inflammatory and IL-10-producing anti-inflammatory T-helper cells

CD4 T-helper (Th) cells secret a variety of inflammatory cytokines and play critical roles in host defense against invading foreign pathogens. On the other hand, uncontrolled inflammatory responses mediated by Th cells may result in tissue damage and inflammatory disorders including autoimmune and allergic diseases. Thus, the induction of anti-inflammatory cytokine expression becomes an important "brake" to repress and/or terminate aberrant and/or unnecessary immune responses. Interleukin-10 (IL-10) is one of the most important anti-inflammatory cytokines to limit inflammatory Th cells and immunopathology and to maintain tissue homeostasis. Many studies have indicated that Th cells can be a major source of IL-10 under specific conditions both in mouse and human and that extracellular signals and cell intrinsic molecular switches are required to turn on and off Il10 expression in different Th cells. In this review, we will highlight the recent findings that have enhanced our understanding on the mechanisms of IL-10 induction in distinct Th-cell subsets, including Th1, Th2, and Th17 cells, as well as the importance of these IL-10-producing anti-inflammatory Th cells in immunity and inflammation.

Extracts of the leaves of Pyrus ussuriensis Maxim. Alleviate itch sensation via TSLP-dependent manner in mouse models of atopic dermatitis

Pyrus ussuriensis Maxim. commonly known as "Sandolbae" in Korean is a pear tree widely distributed across East Asia. Recent studies indicate that P. ussuriensis Maxim. leaves (PUL) have antipruritic effects. This study aimed to determine the effects of PUL extract and its fractions in decreasing the itch sensation and skin lesions in two distinct animal models of atopic dermatitis (AD) induced by dinitrofluorobenzene (DNFB) or house dust mite (HDM). Our results showed that the total ethanol extract of PUL decreased the scratching behavior in mice with DNFB- and HDM-induced AD. Moreover, the ethyl acetate fraction of PUL significantly improved the overall condition of the mice with AD induced by HDM. Further, we used HEK293T cells that express receptors and ion channels for thymic stromal lymphopoietin (TSLP), a potent pruritogen for AD, to determine the mechanisms underlying the antipruritic effects of PUL extract/fractions. Specific subfractions of the PUL strongly inhibited the increase in calcium levels induced by TSLP. In addition, the specific subfraction of PUL inhibited the TSLP-induced increase in calcium levels in cultured mouse dorsal root ganglia neurons. Thus, our results showed that the PUL extract could be effective for alleviating pruritus, and the antipruritic effects were exerted probably via the inhibition of the TSLP pathway in peripheral sensory neurons governing the itch sensation in AD.

CDK4/6 inhibitor palbociclib suppresses IgE-mediated mast cell activation

BACKGROUND

Mast cell activation causes degranulation and release of cytokines, thereby promoting inflammation. The aim of this study was to investigate the inhibitory effect of CDK4/6 inhibition on mast cell activation in vitro and in vivo.

METHODS

RBL-2H3 rat basophilic leukemia cells (BLCs) and mouse bone marrow-derived mast cells (BMMCs) were sensitized with anti-dinitrophenol (DNP) immunoglobulin (Ig)E antibodies, stimulated with DNP-human serum albumin (HSA) antigens, and treated with the CDK4/6 inhibitor palbociclib. Histological stains were applied to reveal cytomorphological changes. Murine IgE-mediated passive cutaneous anaphylaxis (PCA) and ovalbumin (OVA)-induced active systemic anaphylaxis (ASA) models were used to examine palbociclib effects on allergic reactions in vivo. Western blots were performed to detect the expression of cell signaling molecules associated with mast cell activation.

RESULTS

Activated BLCs and BMMCs released copious granule-related mediators (histamine and β-hexosaminidase), which was reduced by palbociclib in a concentration-dependent manner. Palbociclib inhibited expression of the mast cell activation marker CD63 in activated BLCs and inhibited granule release (visualized with toluidine blue staining) while preventing morphological changes, (elongated shape maintained) and filamentous actin (F-actin) reorganization. Palbociclib suppressed molecular Lyn and/or mitogen-activated protein kinase (MAPK) signaling associated with mast cell activation in stimulated BLCs and attenuated allergic reactions in PCA mice dose dependently. Palbociclib attenuated body temperature reduction and diminished serum histamine levels in ovalbumin OVA-challenged ASA mice.

CONCLUSION

Palbociclib suppresses IgE-mediated mast cell activation in vitro and in vivo, suggesting that it may be developed into a therapy for mast cell-mediated allergic diseases via inhibition of mast cell degranulation.

Fas Signaling in Dendritic Cells Mediates Th2 Polarization in HDM-Induced Allergic Pulmonary Inflammation

Fas-Fas ligand (FasL) signaling plays an important role in the development of allergic inflammation, but the cellular and molecular mechanisms are still not well known. By using the bone marrow-derived dendritic cell (BMDC) transfer-induced pulmonary inflammation model, we found that house dust mite (HDM)-stimulated FAS-deficient BMDCs induced higher Th2-mediated allergic inflammation, associated with increased mucus production and eosinophilic inflammation. Moreover, FAS-deficient BMDCs promoted Th2 cell differentiation upon HDM stimulation in vitro. Compared to wild-type BMDCs, the Fas-deficient BMDCs had increased ERK activity and decreased IL-12 production upon HDM stimulation. Inhibition of ERK activity could largely increase IL-12 production, consequently restored the increased Th2 cytokine expression of OT-II CD4⁺ T cells activated by Fas-deficient BMDCs. Thus, our results uncover an important role of DC-specific Fas signaling in Th2 differentiation and allergic inflammation, and modulation of Fas signaling in DCs may offer a useful strategy for the treatment of allergic inflammatory diseases.

Chronic stress induced duration dependent alterations in immune system and their reversibility in rats

The objective was to find out whether severity of stress effects on immunity increases with duration of exposure and recovery depends on duration of exposure. Adult male rats (n = 30) were subjected to restraint (1 h) followed by forced swimming exercise (15 min) after a gap of 4 h daily for 2, 4 and 8 weeks and allowed to recover for 6 weeks after each exposure period. Exposure of rats to stress resulted in duration dependent significant decreases in leukocyte count, phagocytic indices of neutrophils, number of bone marrow stem cells and serum levels of IL-12 and increases in apoptotic index of peripheral blood mononuclear cells and serum levels of IL-10. The alterations in counts of neutrophils, total immunoglobulin content, phagocytic index, apoptotic index of peripheral blood mononuclear cells and serum levels of IL-10 returned to control levels in recovery group rats of 2 and 4 weeks exposure but not in that of 8 weeks exposure. However, alterations in number and apoptotic index of bone marrow stem cells returned to control levels in 2, 4 and 8 weeks stress recovery groups. The results for the first time reveal that increase in duration of exposure results in more severe damage in immune system and that shorter the exposure period, faster the recovery. In addition, in vitro study for the first time showed that corticosterone causes apoptosis of peripheral blood mononuclear cells and bone marrow stem cells in dose dependent manner. Hence death of leukocytes and their stem cells is the major cause of stress induced immune dysfunction.

The CXCR4-STAT3-IL-10 Pathway Controls the Immunoregulatory Function of Chronic Lymphocytic Leukemia and Is Modulated by Lenalidomide

Chronic lymphocytic leukemia (CLL) cells possess regulatory functions comparable to those of normal B10 cells, a regulatory B cell subset that suppresses effector T-cell function through STAT3-mediated IL-10 production. However, the mechanisms governing IL-10 production by CLL cells are not fully understood. Here, we show that the CXC chemokine ligand 12 (CXCL12)–CXCR4–STAT3 axis regulates IL-10 production by CLL cells and their ability to suppress T-cell effector function through an IL-10 mediated mechanism. Knockdown of STAT3 significantly impaired the ability of CLL cells to produce IL-10. Furthermore, experiments to assess the role of lenalidomide, an immunomodulatory agent with direct antitumor effect as well as pleiotropic activity on the immune system, showed that this agent prevents a CXCL12-induced increase in p-S727-STAT3 and the IL-10 response by CLL cells. Lenalidomide also suppressed IL-10-induced Y705-STAT3 phosphorylation in healthy T cells, thus reversing CLL-induced T-cell dysfunction. We conclude that the capacity of CLL cells to produce IL-10 is mediated by the CXCL12–CXCR4–STAT3 pathway and likely contributes to immunodeficiency in patients. Lenalidomide appears to be able to reverse CLL-induced immunosuppression through including abrogation of the CXCL12–CXCR4–S727–STAT3-mediated IL-10 response by CLL cells and prevention of IL-10-induced phosphorylation of Y705-STAT3 in T cells.

Translational Animal Models of Atopic Dermatitis for Preclinical Studies

There is a medical need to develop new treatments for patients suffering from atopic dermatitis (AD). To improve the discovery and testing of novel treatments, relevant animal models for AD are needed. Generally, these animal models mimic different aspects of the pathophysiology of human AD, such as skin barrier defects and Th2 immune bias with additional Th1 and Th22, and in some populations Th17, activation. However, the pathomechanistic characterization and pharmacological validation of these animal models are generally incomplete. In this paper, we review animal models of AD in the context of preclinical use and their possible translation to the human disease. Most of these models use mice, but we will also critically evaluate dog models of AD, as increasing information on disease mechanism show their likely relevance for the human disease.

Combined treatment with H1 and H4 receptor antagonists reduces inflammation in a mouse model of atopic dermatitis

BACKGROUND

Histamine 4 receptor (H4R) antagonists are considered as new therapeutics for the treatment of atopic dermatitis (AD) and first clinical trials have already shown promising results. Histamine 1 receptor (H1R) antagonists are traditionally used to treat AD although the evidence for the efficacy is weak. The combined blockade of both, H1R and H4R, might provide synergistic anti-inflammatory.

OBJECTIVE

The study was performed to test the anti-inflammatory potential of a combined treatment with an H1R and an H4R antagonist in a mouse AD model.

METHODS

The development of ovalbumin-induced AD-like skin lesions was analysed mice treated with the H1R inverse agonist mepyramine, the H4R antagonist JNJ-39758979 or a combination of both.

RESULTS

Mice treated with mepyramine plus JNJ-39758979 showed less severe skin lesions, with a diminished influx of inflammatory cells, a reduced epidermal thickening and a lower level of IL-33 in lesional skin. Scratching behaviour was ameliorated in mice treated with the combination. Moreover, total numbers of skin-draining lymph node cells and splenocytes were significantly reduced. Both substances given alone did not elicit this strong anti-inflammatory effect.

CONCLUSION

H1R and H4R antagonists provide synergistic anti-inflammatory effects in a mouse model of AD. The combined therapy with H1R and H4R antagonists might represent a new strategy for the treatment of AD.

Therapeutic effects of orally administered CJLP55 for atopic dermatitis via the regulation of immune response

Atopic dermatitis (AD) is an inflammatory skin condition accompanied by symptoms such as edema and hemorrhage. Kimchi is a traditional fermented Korean dish consisting of various probiotics. In this study, the therapeutic effect of Lactobacillus plantarum CJLP55 isolated from Kimchi was studied in AD-induced mice. Orally administered Lactobacillus strain, CJLP55, suppressed AD symptoms and high serum IgE levels. CJLP55 administration reduced the thickness of the epidermis, infiltration of mast cells and eosinophils into the skin lesion, enlargement of axillary lymph nodes, and increase in cell population in axillary lymph nodes. CJLP55 treatment decreased the production of type 2 cytokines, such as interleukin (IL)-4, IL-5, IL-10, IL-12, interferon (IFN)-γ, and IL-6,which were stimulated by house dust mite extracts, in the axillary lymph node cells. Orally administered CJLP55 exhibited a therapeutic effect on house dust mite-induced AD in NC/Nga mice after onset of the disease by altering immune cell activation. The Lactobacillus strain, CJLP55, isolated from Kimchi, suppressed AD. Our results suggest its possible use as a potential candidate for management of AD.

Interferon response factor-3 promotes the pro-Th2 activity of mouse lung CD11b+ conventional dendritic cells in response to house dust mite allergens

Very few transcription factors have been identified that are required by antigen-presenting cells (APCs) to induce T helper type 2 (Th2) responses. Because lung CD11b⁺ conventional dendritic cells (CD11b⁺ cDCs) are responsible for priming Th2 responses in house-dust mite (HDM)-induced airway allergy, we used them as a model to identify transcriptional events regulating the pro-Th2 activity of cDCs. Transcriptomic profiling of lung CD11b⁺ cDCs exposed to HDM in vivo revealed first that HDM triggers an antiviral defence-like response, and second that the majority of HDM-induced transcriptional changes depend on the transcription factor Interferon Response Factor-3 (Irf3). Validating the functional relevance of these observations, Irf3-deficient CD11b⁺ cDCs displayed reduced pro-allergic activity. Indeed, Irf3-deficient CD11b⁺ cDCs induced less Th2, more regulatory T cell, and similar Th1 differentiation in naïve CD4⁺ T cells compared to their wild-type counterparts. The altered APC activity of Irf3 CD11b⁺ cDCs was associated with reduced expression of CD86 and was phenocopied by blocking CD86 activity in wild-type CD11b⁺ cDCs. Altogether, these results establish Irf3, known mostly for its role in antiviral responses, as a transcription factor involved in the induction of Th2 responses through the promotion of pro-Th2 costimulation in CD11b⁺ DCs.

Blood Cytokine Profiles Associated with Distinct Patterns of Bronchopulmonary Dysplasia among Extremely Low Birth Weight Infants

OBJECTIVE

To explore differences in blood cytokine profiles among distinct bronchopulmonary dysplasia (BPD) patterns.

STUDY DESIGN

We evaluated blood spots collected from 943 infants born at ≤1000 g and surviving to 28 days on postnatal days 1, 3, 7, 14, and 21 for 25 cytokines. Infants were assigned to the following lung disease patterns: (1) no lung disease (NLD); (2) respiratory distress syndrome without BPD; (3) classic BPD (persistent exposure to supplemental oxygen until 28 days of age); or (4) atypical BPD (period without supplemental oxygen before 28 days). Median cytokine levels for infants with BPD were compared with the IQR of results among infants with NLD.

RESULTS

The distribution of enrolled infants by group was as follows: 69 (NLD), 73 (respiratory distress syndrome), 381 (classic BPD), and 160 (atypical BPD). The remaining 260 infants could not be classified because of missing data (104) or not fitting a predefined pattern (156). Median levels of 3 cytokines (elevated interleukin [IL]-8, matrix metalloproteinase-9; decreased granulocyte macrophage colony-stimulating factor) fell outside the IQR for at least 2 time points in both infants with atypical and classic BPD. Profiles of 7 cytokines (IL-6, IL-10, IL-18, macrophage inflammatory protein-1α, C-reactive protein, brain-derived neurotrophic factor, regulated on activation, normal T cell expressed and secreted) differed between infants with classic and atypical BPD.

CONCLUSIONS

Blood cytokine profiles may differ between infants developing classic and atypical BPD. These dissimilarities suggest the possibility that differing mechanisms could explain the varied patterns of pathophysiology of lung disease in extremely premature infants.

IL-10 Enhances IgE-Mediated Mast Cell Responses and Is Essential for the Development of Experimental Food Allergy in IL-10-Deficient Mice

IL-10 is a key pleiotropic cytokine that can both promote and curb Th2-dependent allergic responses. In this study, we demonstrate a novel role for IL-10 in promoting mast cell expansion and the development of IgE-mediated food allergy. Oral OVA challenge in sensitized BALB/c mice resulted in a robust intestinal mast cell response accompanied by allergic diarrhea, mast cell activation, and a predominance of Th2 cytokines, including enhanced IL-10 expression. In contrast, the development of intestinal anaphylaxis, including diarrhea, mast cell activation, and Th2 cytokine production, was significantly attenuated in IL-10(-/-) mice compared with wild-type (WT) controls. IL-10 also directly promoted the expansion, survival, and activation of mast cells; increased FcεRI expression on mast cells; and enhanced the production of mast cell cytokines. IL-10(-/-) mast cells had reduced functional capacity, which could be restored by exogenous IL-10. Similarly, attenuated passive anaphylaxis in IL-10(-/-) mice could be restored by IL-10 administration. The adoptive transfer of WT mast cells restored allergic symptoms in IL-10(-/-) mice, suggesting that the attenuated phenotype observed in these animals is due to a deficiency in IL-10-responding mast cells. Lastly, transfer of WT CD4 T cells also restored allergic diarrhea and intestinal mast cell numbers in IL-10(-/-) mice, suggesting that the regulation of IL-10-mediated intestinal mast cell expansion is T cell dependent. Our observations demonstrate a critical role for IL-10 in driving mucosal mast cell expansion and activation, suggesting that, in its absence, mast cell function is impaired, leading to attenuated food allergy symptoms.

Cocoa Diet Prevents Antibody Synthesis and Modifies Lymph Node Composition and Functionality in a Rat Oral Sensitization Model

Cocoa powder, a rich source of polyphenols, has shown immunomodulatory properties in both the intestinal and systemic immune compartments of rats. The aim of the current study was to establish the effect of a cocoa diet in a rat oral sensitization model and also to gain insight into the mesenteric lymph nodes (MLN) activities induced by this diet. To achieve this, three-week-old Lewis rats were fed either a standard diet or a diet with 10% cocoa and were orally sensitized with ovalbumin (OVA) and with cholera toxin as a mucosal adjuvant. Specific antibodies were quantified, and lymphocyte composition, gene expression, and cytokine release were established in MLN. The development of anti-OVA antibodies was almost totally prevented in cocoa-fed rats. In addition, this diet increased the proportion of TCRγδ+ and CD103+CD8+ cells and decreased the proportion of CD62L+CD4+ and CD62L+CD8+ cells in MLN, whereas it upregulated the gene expression of OX40L, CD11c, and IL-1β and downregulated the gene expression of IL-17α. In conclusion, the cocoa diet induced tolerance in an oral sensitization model accompanied by changes in MLN that could contribute to this effect, suggesting its potential implication in the prevention of food allergies.

ΔNp63 regulates IL-33 and IL-31 signaling in atopic dermatitis

Atopic dermatitis (AD) is the most common inflammatory skin disease with no well-delineated cause or effective cure. Here we show that the p53 family member p63, specifically the ΔNp63, isoform has a key role in driving keratinocyte activation in AD. We find that overexpression of ΔNp63 in transgenic mouse epidermis results in a severe skin phenotype that shares many of the key clinical, histological and molecular features associated with human AD. This includes pruritus, epidermal hyperplasia, aberrant keratinocyte differentiation, enhanced expression of selected cytokines and chemokines and the infiltration of large numbers of inflammatory cells including type 2  T-helper cells – features that are highly representative of AD dermatopathology. We further demonstrate several of these mediators to be direct transcriptional targets of ΔNp63 in keratinocytes. Of particular significance are two p63 target genes, IL-31 and IL-33, both of which are key players in the signaling pathways implicated in AD. Importantly, we find these observations to be in good agreement with elevated levels of ΔNp63 in skin lesions of human patients with AD. Our studies reveal an important role for ΔNp63 in the pathogenesis of AD and offer new insights into its etiology and possible therapeutic targets.

Biomimetic proopiomelanocortin suppresses capsaicin-induced sensory irritation in humans

Sensitive skin is a frequently mentioned cosmetic complaint. Addition of a biomimetic of neuromediator has recently appeared as a promising new way to cure skin care product problems. This study was aimed to assess the inhibitory effect of a biomimetic lipopeptide derived from proopiomelanocortin (bPOMC) on capsaicin-induced sensory irritation in human volunteers and also to compare its protective effect with that of the well-known anti irritant strontium chloride. The effect of each test compound was studied on 28 selected healthy volunteers with sensitive skin in accordance with a double-blind vehicle-controlled protocol. From day 1 to day 13 each group was applied the test compound (bPOMC or strontium chloride) to one wing of the nose and the corresponding placebo (vehicle) to the other side twice daily. On days 0 and 14, acute skin irritation was induced by capsaicin solution and quantified using clinical stinging test assessments. Following the application of capsaicin solution, sensory irritation was evaluated using a 4-point numeric scale. The sensations perceived before and after treatment (on days 0 and 14) was calculated for the two zones (test materials and vehicle). Ultimately the percentage of variation between each sample and the placebo and also the inhibitory effect of bPOMC compared to that of strontium chloride were reported. Clinical results showed that after two weeks treatment, the levels of skin comfort reported in the group treated with bPOMC were significantly higher than those obtained in the placebo group and the inhibitory effect of bPOMC was about 47% higher than that of strontium chloride. The results of the present study support the hypothesis that biomimetic peptides may be effective on sensitive skin.

Filaggrin deficiency promotes the dissemination of cutaneously inoculated vaccinia virus

BACKGROUND

Eczema vaccinatum is a life-threatening complication of smallpox vaccination in patients with atopic dermatitis (AD) characterized by dissemination of vaccinia virus (VV) in the skin and internal organs. Mutations in the filaggrin (FLG) gene, the most common genetic risk factor for AD, confer a greater risk for eczema herpeticum in patients with AD, suggesting that it impairs the response to cutaneous viral infections.

OBJECTIVE

We sought to determine the effects of FLG deficiency on the response of mice to cutaneous VV inoculation.

METHODS

VV was inoculated by means of scarification of unsensitized skin or skin topically sensitized with ovalbumin in FLG-deficient flaky tail (ft/ft) mice or wild-type (WT) control mice. The sizes of primary and satellite skin lesions were measured, and hematoxylin and eosin staining was performed. VV genome copy numbers and cytokine mRNA levels were measured by using quantitative PCR.

RESULTS

VV inoculation in unsensitized skin of ft/ft mice, independent of the matted hair mutation, resulted in larger primary lesions, more abundant satellite lesions, heavier viral loads in internal organs, greater epidermal thickness, dermal cellular infiltration, and higher local Il17a, Il4, Il13, and Ifng mRNA levels than in WT control mice. VV inoculation at sites of topical ovalbumin application amplified all of these features in ft/ft mice but had no detectable effect in WT control mice. The number of satellite lesions and the viral loads in internal organs after cutaneous VV inoculation were significantly reduced in both unsensitized and topically sensitized ft/ftxIl17a(-/-) mice.

CONCLUSION

FLG deficiency predisposes to eczema vaccinatum. This is mediated primarily through production of IL-17A.

Age-associated inflammation connects RAS-induced senescence to stem cell dysfunction and epidermal malignancy

Aging is the single biggest risk factor for malignant transformation. Among the most common age-associated malignancies are non-melanoma skin cancers, comprising the most common types of human cancer. Here we show that mutant H-Ras activation in mouse epidermis, a frequent event in cutaneous squamous cell carcinoma (SCC), elicits a differential outcome in aged versus young mice. Whereas H-Ras activation in the young skin results in hyperplasia that is mainly accompanied by rapid hair growth, H-Ras activation in the aged skin results in more dysplasia and gradual progression to in situ SCC. Progression is associated with increased inflammation, pronounced accumulation of immune cells including T cells, macrophages and mast cells as well as excessive cell senescence. We found not only an age-dependent increase in expression of several pro-inflammatory mediators, but also activation of a strong anti-inflammatory response involving enhanced IL4/IL10 expression and immune skewing toward a Th2 response. In addition, we observed an age-dependent increase in the expression of Pdl1, encoding an immune suppressive ligand that promotes cancer immune evasion. Moreover, upon switching off oncogenic H-Ras activity, young but not aged skin regenerates successfully, suggesting a failure of the aged epidermal stem cells to repair damaged tissue. Our findings support an age-dependent link between accumulation of senescent cells, immune infiltration and cancer progression, which may contribute to the increased cancer risk associated with old age.