LIGHT signaling through LTßR and HVEM in keratinocytes promotes psoriasis and atopic dermatitis-like skin inflammation.

Psoriasis (PS) and atopic dermatitis (AD) are common skin inflammatory diseases characterized by hyper-responsive keratinocytes. Although, some cytokines have been suggested to be specific for each disease, other cytokines might be central to both diseases. Here, we show that Tumor necrosis factor superfamily member 14 (TNFSF14), known as LIGHT, is required for experimental PS, similar to its requirement in experimental AD. Mice devoid of LIGHT, or deletion of either of its receptors, lymphotoxin ß receptor (LTßR) and herpesvirus entry mediator (HVEM), in keratinocytes, were protected from developing imiquimod-induced psoriatic features, including epidermal thickening and hyperplasia, and expression of PS-related genes. Correspondingly, in single cell RNA-seq analysis of PS patient biopsies, LTßR transcripts were found strongly expressed with HVEM in keratinocytes, and LIGHT was upregulated in T cells. Similar transcript expression profiles were also seen in AD biopsies, and LTßR deletion in keratinocytes also protected mice from allergen-induced AD features. Moreover, in vitro, LIGHT upregulated a broad spectrum of genes in human keratinocytes that are clinical features of both PS and AD skin lesions. Our data suggest that agents blocking LIGHT activity might be useful for therapeutic intervention in PS as well as in AD.

TNF-like weak inducer of apoptosis inhibition is comparable to IL-13 blockade in ameliorating atopic dermatitis inflammation.

BACKGROUND: Targeting IL-13 is highly efficacious in patients with Th2-biased atopic dermatitis (AD), but inhibition of other inflammatory molecules might also limit disease. We investigated the importance of the TNF family cytokine TNF-like weak inducer of apoptosis (TWEAK; TNFSF12) to keratinocyte dysregulation and the pathogenesis of AD in mice and also tested if blocking TWEAK has a similar therapeutic effect as targeting IL-13. METHODS: Conditional knockout mice lacking Fn14 (TNFRSF12A), the receptor for TWEAK, only in keratinocytes, were repetitively sensitized with house dust mite allergen and analyzed for AD-like skin inflammation. To determine the translational potential, wild-type mice with AD were therapeutically treated with anti-TWEAK and/or anti-IL-13 antibodies, and skin inflammation was assessed. RESULTS: Mice deficient in Fn14 in keratinocytes were resistant to developing maximal clinical features of AD, exhibiting reduced epidermal hyperplasia and dermal thickening, less skin infiltration of immune cells, and downregulated inflammatory gene expression. Moreover, therapeutic neutralization of TWEAK in wild-type mice with AD reduced all of the pathological features to a comparable extent as blocking IL-13. CONCLUSIONS: The activity of TWEAK in keratinocytes contributes to AD development, and neutralizing TWEAK represents a future potential therapeutic option in human AD similar to targeting IL-13.

A Deficiency in the Cytokine TNFSF14/LIGHT Limits Inflammation and Remodeling in Murine Eosinophilic Esophagitis.

Eosinophilic esophagitis (EoE) is a chronic type 2 allergic disease, with esophageal tissue remodeling as the mechanism behind clinical dysphagia and strictures. IL-13 is thought to be a central driver of disease, but other inflammatory factors, such as IFNs and TNF superfamily members, have been hypothesized to play a role in disease pathogenesis. We recently found that the cytokine TNFSF14/LIGHT is upregulated in the esophagus of patients with EoE and that LIGHT promotes inflammatory activity in esophageal fibroblasts. However, the global effects of LIGHT on EoE pathogenesis in vivo remain unknown. We investigated the impact of a LIGHT deficiency in a murine model of EoE driven by house dust mite allergen. Chronic intranasal challenge with house dust mite promoted esophageal eosinophilia and increased CD4+ T cell numbers and IL-13 and CCL11 production in wild-type mice. Esophageal remodeling was reflected by submucosal collagen accumulation, increased muscle density, and greater numbers of fibroblasts. LIGHT-/- mice displayed normal esophageal eosinophilia, but exhibited reduced frequencies of CD4 T cells, IL-13 expression, submucosal collagen, and muscle density and a decrease in esophageal accumulation of fibroblasts. In vitro, LIGHT increased division of human esophageal fibroblasts and selectively enhanced IL-13-mediated expression of a subset of inflammatory and fibrotic genes. These results show that LIGHT contributes to various features of murine EoE, impacting the accumulation of CD4 T cells, IL-13 production, fibroblast proliferation, and esophagus remodeling. These findings suggest that LIGHT may be, to our knowledge, a novel therapeutic target for the treatment of EoE.

A Deficiency in the Cytokine TNFSF14/LIGHT Limits Inflammation and Remodeling in Murine Eosinophilic Esophagitis.

Eosinophilic esophagitis (EoE) is a chronic type 2 allergic disease, with esophageal tissue remodeling as the mechanism behind clinical dysphagia and strictures. IL-13 is thought to be a central driver of disease, but other inflammatory factors, such as IFNs and TNF superfamily members, have been hypothesized to play a role in disease pathogenesis. We recently found that the cytokine TNFSF14/LIGHT is upregulated in the esophagus of patients with EoE and that LIGHT promotes inflammatory activity in esophageal fibroblasts. However, the global effects of LIGHT on EoE pathogenesis in vivo remain unknown. We investigated the impact of a LIGHT deficiency in a murine model of EoE driven by house dust mite allergen. Chronic intranasal challenge with house dust mite promoted esophageal eosinophilia and increased CD4+ T cell numbers and IL-13 and CCL11 production in wild-type mice. Esophageal remodeling was reflected by submucosal collagen accumulation, increased muscle density, and greater numbers of fibroblasts. LIGHT-/- mice displayed normal esophageal eosinophilia, but exhibited reduced frequencies of CD4 T cells, IL-13 expression, submucosal collagen, and muscle density and a decrease in esophageal accumulation of fibroblasts. In vitro, LIGHT increased division of human esophageal fibroblasts and selectively enhanced IL-13-mediated expression of a subset of inflammatory and fibrotic genes. These results show that LIGHT contributes to various features of murine EoE, impacting the accumulation of CD4 T cells, IL-13 production, fibroblast proliferation, and esophagus remodeling. These findings suggest that LIGHT may be, to our knowledge, a novel therapeutic target for the treatment of EoE.

Lymphotoxin beta receptor signaling directly controls airway smooth muscle deregulation and asthmatic lung dysfunction.

BACKGROUND: Dysregulation of airway smooth muscle cells (ASM) is central to the severity of asthma. Which molecules dominantly control ASM in asthma is unclear. High levels of the cytokine LIGHT (aka TNFSF14) have been linked to asthma severity and lower baseline predicted FEV1 percentage, implying that signals through its receptors might directly control ASM dysfunction. OBJECTIVE: Our study sought to determine whether signaling via lymphotoxin beta receptor (LTßR) or herpesvirus entry mediator from LIGHT dominantly drives ASM hyperreactivity induced by allergen. METHODS: Conditional knockout mice deficient for LTßR or herpesvirus entry mediator in smooth muscle cells were used to determine their role in ASM deregulation and airway hyperresponsiveness (AHR) in vivo. Human ASM were used to study signals induced by LTßR. RESULTS: LTßR was strongly expressed in ASM from normal and asthmatic subjects compared to several other receptors implicated in smooth muscle deregulation. Correspondingly, conditional deletion of LTßR only in smooth muscle cells in smMHCCreLTßRfl/fl mice minimized changes in their numbers and mass as well as AHR induced by house dust mite allergen in a model of severe asthma. Intratracheal LIGHT administration independently induced ASM hypertrophy and AHR in vivo dependent on direct LTßR signals to ASM. LIGHT promoted contractility, hypertrophy, and hyperplasia of human ASM in vitro. Distinguishing LTßR from the receptors for IL-13, TNF, and IL-17, which have also been implicated in smooth muscle dysregulation, LIGHT promoted NF-κB-inducing kinase-dependent noncanonical nuclear factor kappa-light-chain enhancer of activated B cells in ASM in vitro, leading to sustained accumulation of F-actin, phosphorylation of myosin light chain kinase, and contractile activity. CONCLUSIONS: LTßR signals directly and dominantly drive airway smooth muscle hyperresponsiveness relevant for pathogenesis of airway remodeling in severe asthma.

Anti-CD3 inhibits circulatory and tissue-resident memory CD4 T cells that drive asthma exacerbations in mice.

BACKGROUND: Exacerbations of asthma are thought to be strongly dependent on reactivation of allergen-induced lung tissue-resident and circulatory memory CD4 T cells. Strategies that broadly inhibit multiple T cell populations might then be useful to limit asthma. Accordingly, we tested whether targeting CD3 during exposure to inhaled allergen could prevent the accumulation of lung-localized effector memory CD4 T cells and block exacerbations of asthmatic inflammation. METHODS: House dust mite-sensitized and repetitively challenged BL/6 mice were transiently treated therapeutically with F(ab')2 anti-CD3ε and memory T cell responses and lung inflammation were assessed. PBMCs from HDM-allergic donors were examined for the effect of anti-CD3 on expansion of allergen-reactive T cells. RESULTS: Allergen-sensitized mice undergoing exacerbations of asthma were protected from lung inflammation by transient therapeutic treatment with F(ab')2 anti-CD3. Regardless of whether sensitized mice underwent a secondary or tertiary recall response to inhaled allergen, anti-CD3 inhibited all phenotypes of effector memory CD4 T cells in the lung tissue and lung vasculature by 80%-90%, including those derived from tissue-resident and circulatory memory T cells. This did not depend on Treg cells suggesting it was primarily a blocking effect on memory T cell signaling. Correspondingly, anti-CD3 also strongly inhibited proliferation of human allergen-reactive memory CD4 T cells from allergic individuals. In contrast, the number of surviving tissue-resident memory CD4 T cells that were maintained in the lungs at later times was not robustly reduced by anti-CD3. CONCLUSION: Anti-CD3 F(ab')2 administration at the time of allergen exposure represents a viable strategy for limiting the immediate activity of allergen-responding memory T cells and asthma exacerbations.

Responding to light signals: a comprehensive update on photomorphogenesis in cyanobacteria.

Cyanobacteria are ancestors of chloroplast and perform oxygen-evolving photosynthesis similar to higher plants and algae. However, an obligatory requirement of photons for their growth results in the exposure of cyanobacteria to varying light conditions. Therefore, the light environment could act as a signal to drive the developmental processes, in addition to photosynthesis, in cyanobacteria. These Gram-negative prokaryotes exhibit characteristic light-dependent developmental processes that maximize their fitness and resource utilization. The development occurring in response to radiance (photomorphogenesis) involves fine-tuning cellular physiology, morphology and metabolism. The best-studied example of cyanobacterial photomorphogenesis is chromatic acclimation (CA), which allows a selected number of cyanobacteria to tailor their light-harvesting antenna called phycobilisome (PBS). The tailoring of PBS under existing wavelengths and abundance of light gives an advantage to cyanobacteria over another photoautotroph. In this work, we will provide a comprehensive update on light-sensing, molecular signaling and signal cascades found in cyanobacteria. We also include recent developments made in other aspects of CA, such as mechanistic insights into changes in the size and shape of cells, filaments and carboxysomes.

Combination blockade of OX40L and CD30L inhibits allergen-driven memory TH2 cell reactivity and lung inflammation.

BACKGROUND: The selective reduction of memory TH2 cell responses could be key to affording tolerance and protection from the recurrence of damaging allergic pathology. OBJECTIVE: We asked whether TNF family costimulatory molecules cooperated to promote accumulation and reactivity of effector memory CD4 T cells to inhaled complex allergen, and whether their neutralization could promote airway tolerance to subsequent reexposure to allergen. METHODS: Mice were sensitized intraperitoneally or intranasally with house dust mite and challenged with intranasal allergen after memory had developed. We assessed whether single or combined blockade of OX40L/CD252 and CD30L/CD153 inhibited memory T cells from driving acute asthmatic lung inflammation and protected mice following exposure to allergen at a later time. RESULTS: OX40- or CD30-deficient animals showed strong or partial protection against allergic airway inflammation; however, neutralizing either molecule alone during the secondary response to allergen had little effect on the frequency of effector memory CD4 T cells formed and acute lung inflammation. In contrast, a significant reduction in eosinophilic inflammation was observed when OX40L and CD30L were simultaneously neutralized, with dual blockade inhibiting effector memory TH2 cell expansion in the lungs, whereas formation of peripherally induced regulatory T cells remained intact. Moreover, dual blockade during the secondary response resulted in a tolerogenic state such that mice did not develop a normal tertiary memory TH2 cell and lung inflammatory response when challenged weeks later with allergen. CONCLUSION: Memory T-cell responses to complex allergens are controlled by several TNF costimulatory interactions, and their combination targeting might represent a strategy to reduce the severity of inflammatory reactions following reexposure to allergen.

Maillard reaction in food allergy: Pros and cons.

Food allergens have a notable potential to induce various health concerns in susceptible individuals. The majority of allergenic foods are usually subjected to thermal processing prior to their consumption. However, during thermal processing and long storage of foods, Maillard reaction (MR) often takes place. The MR is a non-enzymatic glycation reaction between the carbonyl group of reducing sugars and compounds having free amino groups. MR may sometimes be beneficial by damaging epitope of allergens and reducing allergenic potential, while exacerbation in allergic reactions may also occur due to changes in the motifs of epitopes or neoallergen generation. Apart from these modulations, non-enzymatic glycation can also modify the food protein(s) with various type of advance glycation end products (AGEs) such as Nϵ-(carboxymethyl-)lysine (CML), pentosidine, pyrraline, and methylglyoxal-H1 derived from MR. These Maillard products may act as immunogen by inducing the activation and proliferation of various immune cells. Literature is available to understand pathogenesis of glycation in the context of various diseases but there is hardly any review that can provide a thorough insight on the impact of glycation in food allergy. Therefore, present review explores the pathogenesis with special reference to food allergy caused by non-enzymatic glycation as well as AGEs.

TWEAK functions with TNF and IL-17 on keratinocytes and is a potential target for psoriasis therapy.

TNF and IL-17 are two cytokines that drive dysregulated keratinocyte activity, and their targeting is highly efficacious in patients with psoriasis, but whether these molecules act with other inflammatory factors is not clear. Here, we show that mice having a keratinocyte-specific deletion of Fn14 (Tnfrsf12a), the receptor for the TNF superfamily cytokine TWEAK (Tnfsf12), displayed reduced imiquimod-induced skin inflammation, including diminished epidermal hyperplasia and less expression of psoriasis signature genes. This corresponded with Fn14 being expressed in keratinocytes in human psoriasis lesions and TWEAK being found in several subsets of skin cells. Transcriptomic studies in human keratinocytes revealed that TWEAK strongly overlaps with IL-17A and TNF in up-regulating the expression of CXC chemokines, along with cytokines such as IL-23 and inflammation-associated proteins like S100A8/9 and SERPINB1/B9, all previously found to be highly expressed in the lesional skin of patients with psoriasis. TWEAK displayed strong synergism with TNF or IL-17A in up-regulating messenger RNA for many psoriasis-associated genes in human keratinocytes, including IL23A, IL36G, and multiple chemokines, implying that TWEAK acts with TNF and IL-17 to enhance feedback inflammatory activity. Correspondingly, therapeutic treatment of mice with anti-TWEAK was equally as effective as antibodies to IL-17A or TNF in reducing clinical and immunological features of psoriasis-like skin inflammation and combination targeting of TWEAK with either cytokine had no greater inhibitory effect, reinforcing the conclusion that all three cytokines function together. Thus, blocking TWEAK could be comparable to targeting TNF or IL-17 and might be considered as an alternate therapeutic treatment for psoriasis.

A Comprehensive Review on Mustard-Induced Allergy and Implications for Human Health.

Mustard is widely used in a variety of foods/food products to enhance the flavor and nutritional value that subsequently raise the risk of hypersensitivity reactions. Mustard allergy has been reported for many years and is increasing gradually especially in the areas where its consumption is comparatively higher, and it may be considered among the most important food allergies. A number of relevant clinical studies focused on mustard-induced allergic manifestations are summarized in the current review. In addition, the knowledge regarding the immunological as well as biochemical characteristics of mustard allergens that have been known till date and their cross-reactivity with other food allergens have also been discussed here. Notably, mustard may also be present as a hidden allergen in foods; therefore, it is important to recognize food products that may contain mustard as it may pose potential risk for the allergic individuals. Additionally, the better understanding of the underlying mechanism in mustard allergy is a prerequisite for the development of specific therapeutic procedures. Conclusively, mustard sensitivity should be routinely tested in patients with idiopathic anaphylaxis for the safety of the allergic patients.

Inherent allergic potential of α-dioxygenase fragment: A pathogenesis related protein.

In the course of analyzing amino acid sequence of an allergen (≈20 kDa), we found this protein has a homology with the amino acid sequence of putative α-Dioxygenase fragment (ADF). Allergy caused by many allergens having an enzymatic activity have been reported previously, but allergenicity to neither α-Dioxygenase enzyme nor to it's any constituents has been reported. We sought to purify an ADF (≈19.5 kDa) from chickpea to investigate it's inherent allergic potential in BALB/c mice. The ADF showed IgE-affinity in sera of sensitized BALB/c mice and allergic patients. Enhanced levels of histamine, specific IgE as well as IgG1, IL-4, IL-17, IL-6, IL-2 and IL-10 were observed in the sera of mice treated with ADF allergen. A positive skin Type 1 test and elevated number of mast cells were found in the treated mice. Apart from this, enhanced number of immune cells i.e. CD19+ and CD4+ were also noticed in the ADF treated group. Higher expressions of IL-4 as well as GATA-3 and prominent histological changes were observed in tissues of treated animals. Furthermore, expressions of Th2 cytokines, associated transcription factors and mast cell signaling proteins were also increased at mRNA and protein levels in the intestines of ADF treated mice. Conclusively, present study demonstrated that ADF with molecular weight of 19.5 kDa is a clinical relevant allergen which causes allergic immune responses in BALB/c mice and may play a pivotal role in allergy caused by food containing α-Dioxygenase enzyme in sensitive individuals.

Allergenicity assessment of Buchanania lanzan protein extract in Balb/c mice.

Tree nuts are among "Big Eight" and have been reported globally for causing allergy. Buchanania lanzan (Bl) is one of the major tree nuts consumed by Indian population. However, very little is known about B. lanzan's induced allergic manifestation. Therefore, evaluation of it's allergenic potential was undertaken. Bl-crude protein extract sensitized BALB/c mice sera were used to identify the allergic proteins by it's IgE binding capability. The major IgE binding proteins found with molecular weight of 11, 20, 23, 25, 48, 54, and 65 kDa. Specific IgE, specific IgG1, MCPT-1, PGD2 and histamine were assessed in mice sera. Enormous amount of mast cell infiltration was noted in different organs. The levels of Th1/Th2 transcription factors GATA-3, SOCS3 and STAT-6 were found upregulated, whereas T-bet was downregulated. Furthermore, elevated Th1/Th2 cytokine responses were observed in mice sera. All together, these reactions developed systemic anaphylaxis upon Bl-CPE challenge in sensitized BALB/c mice. In order to confirm the evidences obtained from the studies carried out in BALB/c, the investigation was extended to human subjects as well. Control subjects and allergic patients were subjected to skin prick test (SPT). Later sera collected from those positive to SPT along with controls were used for IgE immunoblotting. The study evaluated the allergic manifestation associated with Bl, and identified it's proteins attributing Bl-mediated allergy. This work may help in managing tree nuts mediated allergies especially due to Buchanania lanzan sensitization.

Pathophysiology of IL-33 and IL-17 in allergic disorders.

Allergic diseases are among common clinical conditions, affecting millions of children and adults throughout the world. Food allergies, skin allergies (atopic dermatitis), and respiratory allergies (allergic rhinitis and asthma) are the common types of allergies. Recently discovered cytokines IL-17 and IL-33 have been found to play an important role in the pathogenicity of various hypersensitive disorders. After exposure to allergens or infection with parasites or viruses, IL-17 and IL-33 producing cells, such as Th17 and specialized epithelial cells respectively, become activated and trigger the pathogenic immune responses in different susceptible conditions. Potent inhibitors of these cytokines have been identified recently that may represent potential therapeutic agents to overcome the clinical complications of allergies. In the present review, we have discussed the cellular sources, modes of action and regulation of IL-17 and IL-33 in the context of hypersensitive diseases. We have also assessed the therapeutic potential of inhibitory molecules that may alter production of both these cytokines, and thus modulate susceptible conditions.

Health Risks and Benefits of Chickpea (Cicer arietinum) Consumption.

Chickpeas (CPs) are one of the most commonly consumed legumes, especially in the Mediterranean area as well as in the Western world. Being one of the most nutritional elements of the human diet, CP toxicity and allergy have raised health concerns. CPs may contain various antinutritional compounds, including protease inhibitors, phytic acid, lectins, oligosaccharides, and some phenolic compounds that may impair the utilization of the nutrients by people. Also, high consumption rates of CPs have enhanced the allergic problems in sensitive individuals as they contain many allergens. On the other hand, beneficial health aspects of CP consumption have received attention from researchers recently. Phytic acid, lectins, sterols, saponins, dietary fibers, resistant starch, oligosaccharides, unsaturated fatty acids, amylase inhibitors, and certain bioactive compounds such as carotenoids and isoflavones have shown the capability of lowering the clinical complications associated with various human diseases. The aim of this paper is to unravel the health risks as well as health-promoting aspects of CP consumption and to try to fill the gaps that currently exist. The present review also focuses on various prevention strategies to avoid health risks of CP consumption using simple but promising ways.

Glycation of clinically relevant chickpea allergen attenuates its allergic immune response in Balb/c mice.

Glycation of food allergens may alter their immunological behaviour. We sought to investigate the impact of glycation on the allergenicity of a food protein. Herein, a chickpea protein (≈26kDa) was purified and characterized as lectin. Further, glycation of this purified protein was carried out. Thereafter, allergic behaviour of this glycated protein was compared with its native form, using various allergic parameters in Balb/c mice. The reduced allergenicity of glycated protein was observed as lesser allergic phenotypes, reduced serum immunoglobulins and allergic mediators, lower mast cells and eosinophil counts, lower protein expressions of Th2 cytokines and associated transcription factors. In addition, more Th1 and less Th2 cytokine production in exposed splenocyte, were evident in the glycated protein treated mice as compared to its native protein treatment. Thus, glycation of the chickpea allergen attenuated the sensitizing potential and allergic responses in Balb/c mice significantly and could also be clinically beneficial.

Purification, characterization and allergenicity assessment of 26kDa protein, a major allergen from Cicer arietinum.

Chickpea (CP), a legume of the family Fabaceae, is an important nutrient-rich food providing protein, essential amino acids, vitamins, dietary fibre, and minerals. Unfortunately, several IgE-binding proteins in CP have been detected that are responsible for allergic manifestations in sensitized population. Therefore, the prevalence of CP induced allergy prompted us towards purification, characterization and allergenicity assessment of a major ∼26kDa protein from chickpea crude protein extract (CP-CPE). Purification of CP 26kDa protein was done using a combination of fractionation and anion exchange chromatography. This protein was further characterized as "Chain A, crystal structure of a plant albumin" from Cicer arietinum with Mol wt 25.8kDa by Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Further, allergenic potential of purified 25.8kDa protein was assessed using in vivo and in vitro model. Purified protein showed IgE-binding capacity with sensitized BALB/c mice and CP allergic patient's sera. Enhanced levels of specific and total IgE, MCP-1, MCPT-1, myeloperoxidase, histamine, prostaglandin D2, and cysteinyl leukotriene were found in sera of mice treated with CP ∼26kDa protein. Further, expressions of Th2 cytokines (i.e. IL-4, IL-5, IL-13), transcription factors (i.e. GATA-3, STAT-6, SOCS-3) and mast cell signaling proteins (Lyn, cFgr, Syk, PLC-γ2, PI-3K, PKC) were also found increased at mRNA and protein levels in the intestines of mice treated with CP ∼26kDa protein. In addition, enhanced release of ß-hexosaminidase, histamine, cysteinyl leukotriene and prostaglandin D2 were observed in RBL2H3 cell line when treated (125µg) with CP 26kDa protein. Conclusively, in vivo and in vitro studies revealed the allergenic potential of purified CP 26kDa protein. Being a potential allergen, plant albumin may play a pivotal role in CP induced allergenicity. Current study will be helpful for better development of therapeutic approaches to prevent the allergenicity in CP sensitized individuals.

Reversion of Asthmatic Complications and Mast Cell Signalling Pathways in BALB/c Mice Model Using Quercetin Nanocrystals.

The tranquillizing effects of quercetin on allergic asthma are promising, but its poor water solubility and bioavailability is still a bottleneck. In this study, an ovalbumin (OVA) sensitized BALB/c mice asthma model was used to investigate the potential of quercetin nanocrystals (nQ) on relieving asthma aggravation. The water soluble nQ was prepared by the homogenization using the high energy sonication method. X-ray diffraction data showed the formation of nQ (10-30 nm) which was in agreement with transmission electron microscopy. The nQ was found to be more stable and soluble in PBS, and sera of BALB/c mice compared to bulk quercetin. Dose dependent experiments with nQ on OVA sensitized asthma mice exhibited significant anti-asthmatic potential of nQ at much lower dose (1 mg/kg body weight) compared to bulk quercetin. The treatment of nQ remarkably resulted in reduced OVA specific immunoglobulin E (sIgE) production, anaphylaxis signs and type 1 skin test. The nQ also significantly modulated the expression of Th2 cytokines like IL-4 and IL-5, which are responsible for IgE class switching and suppressed the degranulation/secretion of different chemical mediators (PGD2, mMCPT-1 Cys-L and TSLP) from activated mast cells. The levels of FcεR1, Syk, c-Yes, PI-3, p-PI-3, PLC-γ2, and p-PLC-γ2 were found to be reduced in the OVA sensitized BALB/c mice treated with nQ compared to those treated with OVA only. The results indicate that nQ alleviate pulmonary inflammation and airway hyporesponsiveness in allergic asthma at much lower dose compared to bulk quercetin and may be considered as a potential drug for the treatment of asthmatic patients.

Cutaneous exposure to clinically-relevant pigeon pea (Cajanus cajan) proteins promote TH2-dependent sensitization and IgE-mediated anaphylaxis in Balb/c mice.

Epicutaneous (EC) sensitization to food allergens may occur when the skin has been lightly damaged. The study here tested whether cutaneous exposure to pigeon pea protein(s) may cause allergic sensitization. BALB/c mice were either orally gavaged or epicutaneously sensitized by repeated application of pigeon pea crude protein extract (CPE) on undamaged areas of skin without any adjuvant; afterwards, both groups were orally challenged with the pigeon pea CPE. Anaphylactic symptoms along with measures of body temperature, MCPT-1, TSLP, pigeon pea-specific IgE and IgG1, myeloperoxidase (MPO) activity, TH2 cytokines, TH2 transcription factors (TFs) and filaggrin expression were determined. Mast cell staining, eosinophil levels and histopathological analysis of the skin and intestines were also performed. In the epicutaneously-sensitized mice, elevated levels of specific IgE and IgG1, as well as of MCPT-1, TSLP, TH2 cytokines and TFs, higher anaphylactic scores and histological changes in the skin and intestine were indicative of sensitization ability via both routes in the pigeon pea CPE-treated hosts. Elevated levels of mast cells were observed in both the skin and intestine; increased levels of eosinophils and MPO activity were noted only in the skin. Decreased levels of filaggrin in skin may have played a key role in the skin barrier dysfunction, increasing the chances of sensitization. Therefore, the experimental data support the hypothesis that in addition to oral exposure, skin exposure to food allergens can promote TH2-dependent sensitization, IgE-mediated anaphylaxis and intestinal changes after oral challenge. Based on this, an avoidance of cutaneous exposures to allergens might prevent development of food anaphylaxis.