A new phenolic acid isolated from Salvia miltiorrhiza ameliorates OVA-induced allergic asthma by regulation of Th17/Treg cells and inflammation through the TLR4 pathway.

Asthma, which is a chronic inflammatory disease of the airways, is usually caused by allergens in which various structures and immune cells are involved. Ephedra sinica, the most commonly used Chinese medicine, has significant clinical effects on asthma, but its components are complex and the mechanism of action has not been fully elucidated. Among its components, we identified an amide alkaloid (EB-A) and investigated its anti-asthmatic activity and the underlying mechanisms. In this study, we replicated an OVA-sensitized/challenged allergic asthma mouse model, and divided the mice into a model (OVA) group, positive drug (Y, 0.5 mg/kg/day) group, and EB-A treatment with low (Low, 10 mg/kg/day) and high dose (High, 20 mg/kg/day) groups. Asthma-related features were analyzed through the airway hyperresponsiveness (AHR), cough and wheeze indexes, allergen-specific IgE, prostaglandin D2 (PDG2), and lung histology in mice. The levels of apoptosis and reactive oxygen species (ROS) in the primary lung cells, cytokines in the serum and broncho-alveolar lavage fluid (BALF), and proteinase-activated receptor-2 (PAR2) pathway activation in the lung tissue were measured to evaluate the inflammatory injury and lung epithelial barrier damage in the mice. Dendritic cell (DC) maturation and mast cell (MC) activation were verified in vitro and in vivo. Furthermore, the effect of a PAR2 activation in lung epithelial cells on the maturation of DCs was evaluated by the co-culture system of (human bronchial epithelial cell lines) 16HBE and bone marrow-derived dendritic cells (BMDCs). The results showed that EB-A inhibited the typical asthmatic phenotypes, as well as lung injury and inflammation, MC activation and degranulation, and DC maturation in the OVA-sensitized/challenged BALB/c mice. In addition, EB-A inhibited the expression of PAR2 in the lung epithelial cells and significantly interfered with the maturation of DCs after inhibiting PAR2. Taken together, our study firstly demonstrated that EB-A could ameliorate OVA-induced allergic asthma by inhibiting MC activation and DC maturation, and the molecular mechanism of EB-A’s anti-asthmatic activity might be mediated by inhibiting PAR2. Our data provide a molecular justification for the use of EB-A in the treatment of allergic asthma.

Ultrastructure of bronchial biopsies from patients with allergic and non-allergic asthma

Total glucosides of peony improve ovalbumin-induced allergic asthma by inhibiting mast cell degranulation

The importance of IgE in airway inflammation and development of AHR in allergen-sensitized mice has been compared and contrasted in different models of sensitization and challenge. Using different modes of sensitization in normal and genetically manipulated mice after anti-IgE treatment, we have been able to distinguish the role of IgE under these different conditions. Striking differences in the three sensitization protocols were delineated in terms of the role of allergen-specific IgE, extent of eosinophilic airway inflammation, and development of AHR (Table 1). The highest levels of IgE and eosinophil infiltration (approximately 20-fold increases) were achieved after systemic sensitization with allergen (plus adjuvant) followed by repeated airway challenge. Passive sensitization with allergen-specific IgE followed by limited airway challenge induced a modest eosinophilic inflammatory response in the airways despite high levels of serum IgE. Exposure to allergen exclusively via the airways also resulted in a modest serum IgE response and a limited eosinophilic inflammatory response (approximately fourfold increases). Under all of these conditions, inhibition of IL-5-mediated eosinophilic airway inflammation was associated with attenuation of AHR. In contrast, the differences in the responses to the different modes of allergen exposure were associated with differences in the requirements for IgE in the development of AHR (Table 1). In the two models associated with mild eosinophil infiltration (passive sensitization and exclusive airway exposure), IgE was required for the development of AHR but did not substantially enhance airway inflammation on its own. However, IgE-allergen interaction was able to enhance T-cell function in vitro and induce T-cell expansion in vivo. In mice systemically sensitized and challenged via the airways, IgE (or IgE-mediated mast-cell activation) was not required for T-cell activation, eosinophilic inflammation and activation in the airways, or development of AHR. This was most clearly seen in B-cell-deficient and mast-cell-deficient, low-IgE-responder mouse strains (B6, B10) and in anti-IgE-treated high-IgEresponder mice (BALB/c). At the same time, we confirmed the importance of IgE in the induction of immediate-type hypersensitivity (mast-cell activation, immediate cutaneous hypersensitivity, passive cutaneous and systemic anaphylaxis). These differences were also highlighted by the means used to detect altered airway function. Passive sensitization and limited airway challenge or exclusive airway exposure to allergen over 10 days elicited changes in airway function that could be detected only in tracheal smooth-muscle preparations exposed to EFS. In contrast, systemic sensitization followed by repeated airway challenge resulted not only in changes in the contractile response to EFS but also in increased responsiveness to inhaled MCh. Thus, these results distinguish not only the differential involvement of IgE and eosinophil numbers but also their contribution to the readouts used to monitor airway function. Based on these studies, we conclude that IgE plays an important role in the development of airway inflammation and AHR under conditions in which limited IL-5-mediated eosinophilic airway infiltration is induced. In conditions where a robust eosinophilic inflammation of the airways is elicited, IgE (and IgE-mediated mast-cell activation) does not appear to be essential for airway inflammation and the development of AHR, detected as increased responsiveness to inhaled MCh. These findings reveal the potential importance of differential targeting in the treatment of allergic diseases with a predominance of IgE-mediated symptoms, e.g., allergic rhinitis and conjunctivitis, where anti-IgE may be an effective therapy, compared to those diseases with a predominant inflammatory component, e.g., AHR in atopic bronchial asthma, where anti-inflammatory or anti-IL-5 therapy may be more beneficial.

Integrated plasma pharmacochemistry and network pharmacology to explore the mechanism of Gerberae Piloselloidis Herba in treatment of allergic asthma

To investigate whether emodin exerts protective effects on mouse with allergic asthma. A mouse model of allergic airway inflflammation was employed. The C57BL/6 mice sensitized and challenged with ovalbumin (OVA) were intraperitoneally administered 10 or 20 mg/kg emodin for 3 days during OVA challenge. Animals were sacrificed 48 h after the last challenge. Inflammatory cell count in the bronchoalveolar lavage fluid (BALF) was measured. The levels of interleukin (IL)-4, IL-5, IL-13 and eotaxin in BALF and level of immunoglobulin E (IgE) in serum were measured with enzyme-linked immuno sorbent assay kits. The mRNA expressions of IL-4, IL-5, heme oxygenase (HO)-1 and matrix metalloproteinase-9 (MMP-9) were determined by real-time quantitative polymerase chain reaction. Emodin induced significant suppression of the number of OVA-induced total inflammatory cells in BALF. Treatment with emodin led to significant decreases in the levels of IL-4, IL-5, IL-13 and eotaxin in BALF and total IgE level in serum. Histological examination of lung tissue revealed marked attenuation of allergen-induced lung eosinophilic inflammation. Additionally, emodin suppressed IL-4, IL-5 and MMP-9 mRNA expressions and induced HO-1 mRNA expression. Emodin exhibits anti-inflammatory activity in the airway inflammation mouse model, supporting its therapeutic potential for the treatment of allergic bronchial asthma.

Patients with complex regional pain syndrome have increased tryptase in the skin of the affected extremity indicating mast cell (MC) accumulation and degranulation, processes known to be mediated by substance P (SP). The dysregulation of SP release from primary afferent neurons is characteristic of complex regional pain syndrome. The authors hypothesized that SP acting through the neurokinin-1 receptor results in mast cell accumulation, degranulation, and nociceptive sensitization in a rat model of complex regional pain syndrome. Groups of 6-10 rats underwent tibia fracture and hind limb casting for 4 weeks, and the hind paw skin was harvested for histologic and immunohistochemical analysis. The effects of a selective neurokinin-1 receptor antagonist (LY303870) and of direct SP intraplantar injection were measured. Dermal MC degranulation induced by sciatic nerve stimulation and the effects of LY303870 on this process were investigated. Finally, the antinociceptive effects of acute and chronic treatment with a MC degranulator (48/80) were tested. The authors observed that fracture caused MC accumulation, activation, and degranulation, which were inhibited by LY303870; the percentage of MCs in close proximity to peptidergic nerve fibers increased after fracture; electrical stimulation caused MC activation and degranulation, which was blocked by LY303870; intraplantar SP-induced MC degranulation and acute administration of 48/80 caused MC degranulation and enhanced postfracture nociception, but MC-depleted animals showed less sensitization. These results indicate that facilitated peptidergic neuron-MC signaling after fracture can cause MC accumulation, activation, and degranulation in the injured limb, resulting in nociceptive sensitization.

Allergic asthma is a stubborn chronic inflammatory disease, and is considered a co-result of various immune cells, especially mast cells, eosinophils and T lymphocytes. At present, the treatment methods of allergic asthma are limited and the side effects are obvious. Traditional Chinese medicine has been used to treat diseases for thousands of years in China. One such example is the treatment of allergic asthma, which take the characteristics of less adverse reactions and obvious curative effect. Tuo-Min-Ding-Chuan Decoction (TMDCD) is a traditional Chinese medicine compound for the treatment of allergic asthma optimized from Ma-Xing-Gan-Shi Decoction (MXGSD), which was put forward in Treatise on Febrile Diseases by Zhang Zhongjing in the Eastern Han Dynasty. The compound shows a significant clinical effect, but the mechanism of its influence on the immune system is still unclear. The purpose of this study was to observe whether TMDCD could alleviate the symptoms of ovalbumin (OVA) challenged allergic asthma mice, and to explore its immune regulatory mechanism, especially on mast cell (MC) degranulation. The results showed TMDCD could not only reduce the airway hyperresponsiveness (AHR), inflammatory cell infiltration and mucus secretion in the lung tissue of OVA challenged mice, but also decrease the levels of total IgE, OVA-specific IgE, histamine and LTC4 in serum. We found that TMDCD can downregulate the expression of Fractalkine, Tryptase ε, IL-25, CCL19, MCP-1, OX40L, Axl, CCL22, CD30, G-CSF, E-selectin, OPN, CCL5, P-selectin, Gas6, TSLP in OVA challenged mice serum by using mouse cytokines antibody array. It has been reported in some literatures that these differentially expressed proteins are related to the occurrence of allergic asthma, such as tryptase ε, MCP-1, CCL5, etc. can be released by MC. And the results of in vitro experiments showed that TMDCD inhibited the degranulation of RBL-2H3 cells stimulated by DNP-IgE/BSA. Taken together, we made the conclusion that TMDCD could reduce the infiltration of inflammatory cells in lung tissue and alleviate airway remodeling in mice with allergic asthma, showed the effects of anti-inflammatory and antiasthmatic. TMDCD could also reduce the levels of IgE, histamine, LTC4, Tryptase ε, and other MC related proteins in the serum of allergic asthma mice, and the in vitro experiments showed that TMDCD could inhibit IgE mediated degranulation and histamine release of RBL-2H3 cells, proved its anti allergic effect.

Mast Cells Play a Crucial Role in Staphylococcus aureus Peptidoglycan-Induced Diarrhea

Allergic asthma is an important phenotype of asthma, accounting for sixty to eighty percent of the whole asthma population. This guideline was divided into 15 chapters, which provided a detailed introduction to epidemiology, pathogenesis, common allergens, clinical manifestation and the principles of diagnosis, treatment and prevention of allergic asthma, and highlighted the similarities and differences of allergic and non-allergic asthma. According to the principles of international and national asthma guidelines, this guideline placed special emphasis on allergen specific immunotherapy, anti-IgE therapy, anti-allergy therapy, management of allergic comorbidities and tertiary prevention. Based on the evidence-based medicine and clinical practice in China, the guideline made recommendations to guide the diagnosis, treatment and management of allergic asthma in China.

Allergen-specific immunotherapy (SIT) induces clinical and immunological tolerance as defined by persistence of clinical benefit and associated long-term immunological parameters after cessation of treatment. Although the efficacy of SIT has been shown in terms of reducing symptoms, medication consumption and ameliorating quality of life in both allergic rhinitis and asthma, there has long been some controversies about effectiveness of SIT in the treatment of allergic asthma. The type of allergen, the dose and protocol of immunotherapy, patient selection criteria, the severity and control of asthma, all are significant contributors to the power of efficacy in allergic asthma. The initiation of SIT in allergic asthma should be considered in case of coexisting of other allergic diseases such as allergic rhinitis, unacceptable adverse effects of medications, patient's preference to avoid long-term pharmacotherapy. Steroid sparing effect of SIT in allergic asthma is also an important benefit particularly in patients who have to use these drugs in high doses for a long-time. Symptomatic asthma is a risk factor for systemic reactions and asthma should be controlled at the time of administration of SIT. Both subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) have been found to be effective in patients with allergic asthma. Although the safety profile of SLIT seems to be better than SCIT, the results of some studies and meta-analyses suggest that the efficacy of SCIT may appear better and earlier than SLIT in children with allergic asthma.

Asthma is characterized by chronic inflammation and respiratory tract remodeling. Peroxisome proliferator-activated receptors (PPARs) play important roles in the pathogenesis and regulation of chronic inflammatory processes in asthma. The role of PPARγ has been studied using synthetic PPARγ agonists in patients with asthma. However, involvement of PPARα/δ has not been studied in asthma. In the present study, we investigated if elafibranor, a PPARα/δ dual agonist, can modulate ovalbumin (OVA)-induced allergic asthma, which is a potential drug candidate for non-alcoholic fatty liver in obese patients. Elafibranor suppresses antigen-induced degranulation in RBL-2H3 mast cells without inducing cytotoxicity in vitro. In mice with OVA-induced allergic asthma, the administration of elafibranor suppressed OVA-induced airway hyper-responsiveness at a dose of 10 mg/kg. Elafibranor also suppressed the OVA-induced increase in immune cells and pro-inflammatory cytokine production in the bronchoalveolar lavage fluid (BALF). Histological studies suggested that elafibranor suppressed OVA-induced lung inflammation and mucin hyper-production in the bronchial airways. In addition, elafibranor suppressed OVA-induced increases in serum immunoglobulin E and IL-13 levels in BALF. Conversely, the present study suggests that elafibranor has the potential for use in patients with allergic asthma.

Epidemiological and clinical studies have suggested that intake of n-3 polyunsaturated fatty acids (PUFA) reduces the incidence of allergic airway diseases and improves pulmonary function in patients with allergic asthma. However, the pharmacological targets of PUFA have not been elucidated upon. We investigated whether free fatty acid receptor 4 (FFA4, also known as GPR120) is a molecular target for beneficial PUFA in asthma therapy. In an ovalbumin (OVA)-induced allergic asthma model, compound A (a selective agonist of FFA4) was administrated before OVA sensitization or OVA challenge in FFA4 wild-type (WT) and knock-out (KO) mice. Compound A treatment of RBL-2H3 cells suppressed mast cell degranulation in vitro in a concentration-dependent manner. Administration of compound A suppressed in vivo allergic characteristics in bronchoalveolar lavage fluid (BALF) and lungs, such as inflammatory cytokine levels and eosinophil accumulation in BALF, inflammation and mucin secretion in the lungs. Compound A-induced suppression was not only observed in mice treated with compound A before OVA challenge, but in mice treated before OVA sensitization as well, implying that compound A acts on mast cells as well as dendritic cells. Furthermore, this suppression by compound A was only observed in FFA4-WT mice and was absent in FFA4-KO mice, implying that compound A action is mediated through FFA4. Activation of FFA4 may be a therapeutic target of PUFA in allergic asthma by suppressing the activation of dendritic cells and mast cells, suggesting that highly potent specific agonists of FFA4 could be a novel therapy for allergic asthma.

BACKGROUND: Bronchial asthma is characterized by chronic eosinophilic inflammatory airway disease associated with bronchial hyperresponsiveness and reversible airway obstruction. Bronchial inflammation in asthma may depend in part on the activation of T helper lymphocytes that elaborate proinflammatory cytokines. T helper (Th) lymphocytes can be divided into two categories ; Th1 lymphocytes, which secrete IL-2, IL-12 and IFN-, and Th2 lymphocytes, which secrete IL-4, IL-5, IL-6 and IL-10. Th2 lymphocytes appear to induce allergic responses, whereas Th1 lymphocytes induce delayed-type hypersensitivity response. Some infections, such as tuberculosis, cultivate a Th1 immunological environment and inhibit Th2 lymphocytes function. The presence of such infections might inhibit Th2 immune responses and thus protect development of atopic diseases. METHOD: 15 patients with allergic bronchial asthma, 10 patients with intrinsic bronchial asthma, and 10 healthy volunteers were studied. The serum concentrations of IFN-, IL-12, IL-4, IL-5, and IL-10 were measured by ELISA method and tuberculin skin test was estimated in different groups. RESULTS: The positive response rates of tuberculin test were 46.7% in patients with allergic asthma , 100% in patients with intrinsic asthma and 60% in normal controls. The positive response rates were significantly lower in patients with allergic asthma than those of in patients with intrinsic asthma (p<0.05). Degree of responses to tuberculin test were 12.09.6mm in patients with allergic asthma, 18.44.5mm in patients with intrinsic asthma and 10.98.8mm in normal controls. The degree of responses were significantly reduced in patients with allergic asthma than those of patients with intrinsic asthma (p<0.05). The serum levels of IL-5 in patients with allergic asthma were significantly higher than in patients with intrinsic asthma and normal controls (p<0.05), although it was insignificant, the serum levels of IL-4 and IL-10 in patients with allergic asthma were higher than that of intrinsic asthma and normal controls. The serum levels of IL-12 and IFN- in patients with allergic asthma and intrinsic asthma were significantly lower than those in normal controls(P<0.05). The serum levels of total immunoglobulin E (IgE) and peripheral blood eosinophile counts in patients with allergic asthma were significantly higher than those in normal controls. Peripheral blood esinophil counts had a significant correlation with the serum levels of total IgE, IL-5 and IL-10 in patients with allergic asthma (p<0.05). CONCLUSION: These results have showed that Th1 lymphocyte functions were lowered and Th2 lymphocyte functions were elevated in patients with allergic asthma than those in normal controls. Suppression of Th1 lymphocyte functions by activation of Th2 lymphocyte might be one of the important aspects of pathogenesis in allergic bronchial asthma.

Asthma is a chronic inflammatory disease affecting the airways in response to certain stimuli. It is characterized by pulmonary inflammation, reversible bronchial constriction, and airway remodelling triggered by exposure to inhaled allergens. Key pathological features include infiltration of the airways by activated eosinophils, lymphocytes and macrophages, damage to the bronchial epithelium, mast cell degranulation, mucous gland hyperplasia and bronchial mucosal thickening by oedema. Infiltrating leukocytes, as well as airway structural cells including smooth muscle, fibroblasts, endothelial and epithelial cells, are all important sources of mediators that drive or exacerbate the asthmatic condition. Extensive work in experimental animal models and studies in the clinic support a central role of allergen-specific T helper type 2 (Th2) lymphocytes in pathophysiological responses. Th2 lymphocytes drive the allergic reaction and activation of inflammatory cells via the production of cytokines crucial to allergic disease, the most important of which are interleukin (IL)-4 and IL-13. These cytokines are known to directly and indirectly drive several aspects of allergic inflammation and have numerous effects on the functional activity of airway structural cells, resulting in subepithelial fibrosis, airway smooth muscle proliferation, and goblet cell hyperplasia. Current asthma therapies are centred on the use of short and long acting bronchodilators, often in combination with corticosteroids, which are largely ineffective or induce resistance in a sub-group of asthmatics. There is clearly a need for more effective drugs for the prevention and treatment of allergic asthma. Hence, IL-4 and IL-13 have been the focus of much research as therapeutic targets that might be beneficial to consider in many asthma phenotypes. The aim of this thesis was to extend our knowledge of the role of the Th2 cytokines, IL-4 and IL-13, in the inflammatory response seen in asthma, using an established sheep experimental model of allergic asthma previously shown to mimic many of the main characteristics of the human condition. An investigation of the kinetics of IL-4 and IL-13 release during the inflammatory response as well as alterations to immune cells due to the effects of IL-4 and IL-13 in the sheep model was the focus of this study. Methods for detecting protein levels of ovine IL-4 and IL-13 in biological fluids by enzyme-linked immunosorbent assay (ELISA) were developed and optimized for use in the present studies. Sandwich ELISAs for the detection of ovine IL-4 and IL-13 were confirmed for specificity and precision, as well as quantitative detection of native proteins. The ELISA assays were then used to investigate temporal changes in the levels of IL-4 and IL-13 in airway fluid (bronchoalveolar lavage or BAL) samples collected during the course of the allergic airway response in the sheep asthma model. In this part of the study, it was found that similar to human asthma, these cytokines are involved and altered during an acute phase of asthmatic inflammation; IL-4 and IL-13 are released by different cellular sources and each exhibit a unique profile of secretion in response to allergen challenge. It is well known that macrophages are amongst the cellular targets of IL-4 and IL-13 and emerging evidence shows that these cells are involved in asthmatic inflammation. Macrophages undergo activation in response to IL-4 and IL-13 and their resultant activities contribute to asthma pathogenesis. The sheep model of asthma is a powerful tool for studying macrophages as it is easy to access large numbers of alveolar macrophages (AMs) at multiple time points. Also, there is evidence showing similarities in the features of activation of human and sheep macrophages. Therefore, taking advantage of the sheep asthma model, the phenotype and activity of AMs were investigated with the aim to better understand IL-4 and IL-13 effects on macrophages, as well as understanding the macrophage characteristics that contribute to asthmatic symptoms. As a result, it was found that AMs from asthmatic sheep undergo a shift in the expression of their markers and activities which may contribute to an altered or compromized immune response in asthma. The research presented in this thesis provides a comprehensive investigation into the complex immunological responses occurring in asthma. Further, this study has strengthened our understanding of the critical elements of asthma disease by further exploring the immunopathological features of the sheep model of allergic asthma. It is hoped that this thesis will contribute towards developing novel and effective targeted therapies for asthma.