Allergic Mouse Model Research Articles

Immunomodulatory features of MSC-derived exosomes decorated with DC-specific aptamer for improving sublingual immunotherapy in allergic mouse model

IntroductionSublingual immunotherapy (SLIT) is an effective and injection-free route for allergen-specific immunotherapy (AIT). Mesenchymal stromal/stem cell (MSC)-derived exosomes (Exo) has been identified as a novel delivery platform with immunomodulatory capacities. In addition, targeting agents such as aptamers (Apt) have been extensively used for specific delivery approaches such as direct delivery of allergen formulations to dendritic cells (DC) to improve the efficacy of specific immunotherapy. In this study, we assessed the effects of MSC-derived Exos containing ovalbumin (Ova) which decorated with DC-specific aptamer in allergic rhinitis mice model.Materials and methodsExos were harvested from adipose tissue-derived MSCs, and Exo-Apt-Ova complex was formulated. Then, Ova-induced allergic asthma model was simulated and sensitized BALB/c mice were treated sublingually with Exo-Apt-Ova complex (5 µg Ova) twice weekly for 8 weeks. Ova-specific IgE levels in serum and concentrations of interferon-gamma (IFN-γ), interleukin (IL)-4, and transforming growth factor-beta (TGF-β) in the supernatant of cultured splenocytes were evaluated using enzyme-linked immunosorbent assay (ELISA). In addition, lung histologic analysis and nasopharyngeal lavage fluid (NALF) cell count were performed.ResultsAdministration of Ova-incorporated Apt-modified Exos dramatically increased IFN-γ and TGF-β levels, and decreased IL-4 and IgE levels. In addition, inflammatory responses in the lung tissue and the number of eosinophils in NALF decreased.ConclusionSLIT using Exo-Ova (5 µg) decorated with DC-specific aptamer induced immunomodulatory responses and remarkably attenuated allergic airway inflammation in mice.

Eosinophil-Airway Epithelial Cells crosstalk reveals the eosinophils-mediated DUOX1 up-regulation in a murine allergic inflammation setting.

Blood and airway eosinophilia represent markers for the endotype-driven treatment of allergic asthma. Little is known on mechanisms that link eosinophils and airway epithelial cells before and after these cells are infiltrated by eosinophils during allergic response. Given that innate immune mechanisms, mainly mediated by epithelial-derived cytokines (IL-33, IL-25, TSLP), induce eosinophil-maturing/attractive substances, we thought to evaluate the crosstalk between eosinophils and airway epithelial cells in the context of IL-33-mediated allergic inflammation. DUOX1 was previously described in clinically relevant aspects of allergic inflammation in a HDM -induced allergic asthma mice model, and in patients with chronic sinusitis or allergic asthma. Thus, we evaluated the involvement of HDM and eosinophils in the regulation of DUOX1 in airway epithelial cells. To recapitulate the lung environment present at the allergen challenge time in acute asthma, we set up an in vitro model based on murine bone marrow-derived eosinophils differentiated with IL-5 and then activated with IL-33 (EOs33) and TC1 or C57 airway epithelial cells. We found that treatment of epithelial cells with HDM induced an eosinophil-attractive environment and increased DUOX1 expression. Importantly, we found that the co-culture of airway epithelial cells with EOs33 or with conditioned medium from EOs33 enhanced the expression of DUOX1, which was further increased by combined stimulation (HDM plus EOs33). Our results suggest that lung recruited EOs once activated by IL-33 could be involved in a crosstalk loop with airway epithelial cells by DUOX1-mediated IL-33 secretion.

Phytotherapeutic BS012 and Its Active Component Ameliorate Allergic Asthma via Inhibition of Th2-Mediated Immune Response and Apoptosis.

Asthma is a chronic inflammatory disorder of the lungs that results in airway inflammation and narrowing. BS012 is an herbal remedy containing Asarum sieboldii, Platycodon grandiflorum, and Cinnamomum cassia extracts. To elucidate the anti-asthma effect of BS012, this study analyzed the immune response, respiratory protection, and changes in metabolic mechanisms in an ovalbumin-induced allergic asthma mouse model. Female BALB/c mice were exposed to ovalbumin to induce allergic asthma. Bronchoalveolar lavage fluid and plasma were analyzed for interleukin and immunoglobulin E levels. Histological analyses of the lungs were performed to measure morphological changes. Apoptosis-related mediators were assayed by western blotting. Plasma and lung tissue metabolomic analyses were performed to investigate the metabolic changes. A T-helper-2-like differentiated cell model was used to identify the active components of BS012. BS012 treatment improved inflammatory cell infiltration, mucus production, and goblet cell hyperplasia in lung tissues. BS012 also significantly downregulated ovalbumin-specific immunoglobulin E in plasma and T-helper-2-specific cytokines, interleukin-4 and -5, in bronchoalveolar lavage fluid. The lungs of ovalbumin-inhaled mice exhibited nerve growth factor-mediated apoptotic protein expression, which was significantly attenuated by BS012 treatment. Ovalbumin-induced abnormalities in amino acid and lipid metabolism were improved by BS012 in correlation with its anti-inflammatory properties and normalization of energy metabolism. Additionally, the differentiated cell model revealed that N-isobutyl-dodecatetraenamide is an active component that contributes to the anti-allergic properties of BS012. The current findings demonstrate the anti-allergic and respiratory protective functions of BS012 against allergic asthma, which can be considered a therapeutic candidate.

Alarmin-loaded extracellular lipid droplets induce airway neutrophil infiltration during type 2 inflammation

Group 2 innate lymphoid cells (ILC2s) play a crucial role in allergic diseases by coordinating a complex network of various effector cell lineages involved in type 2 inflammation. However, their function in regulating airway neutrophil infiltration, a deleterious symptom of severe asthma, remains unknown. Here, we observed ILC2-dependent neutrophil accumulation in the bronchoalveolar lavage fluid (BALF) of allergic mouse models. Chromatography followed by proteomics analysis identified the alarmin high mobility group box-1 (HMGB1) in the supernatant of lung ILC2s initiated neutrophil chemotaxis. Genetic perturbation of Hmgb1 in ILC2s reduced BALF neutrophil numbers and alleviated airway inflammation. HMGB1 was loaded onto the membrane of lipid droplets (LDs) released from activated lung ILC2s. Genetic inhibition of LD accumulation in ILC2s significantly decreased extracellular HMGB1 abundance and BALF neutrophil infiltration. These findings unveil a previously uncharacterized extracellular LD-mediated immune signaling delivery pathway by which ILC2s regulate airway neutrophil infiltration during allergic inflammation.

Mitigation of allergic asthma in mice: A compound mixture comprising luteolin, arbutin, and marmesin from Gerbera Piloselloides Herba by suppression of PI3K/Akt pathway

BackgroundGerberae Piloselloidis Herba (GPH) exhibits notable efficacy in alleviating allergic asthma. Previous studies in our research have identified a mixture of luteolin, arbutin, and marmesin as effective components of GPH in treating allergic asthma. However, the underlying mechanism remains unclear. This study aims to elucidate the molecular mechanism of these active components. MethodUsing an ovalbumin (OVA)-induced allergic asthma mouse model, various treatment groups were administered, including GPH, the active component mixture (termed "Mixture") containing luteolin, arbutin, and marmesin, and a positive drug (dexamethasone, DEX). Relevant indices were assessed, including behavioral characteristics, inflammatory cell counts, cytokine levels, histopathological examination of lung tissue, apoptosis, and expression of key proteins such as Caspase-3, Bax, Bcl-2, PI3K, p-PI3K, Akt, and p-Akt. The effect of the Mixture on the PI3K/Akt signaling pathway was further verified using the PI3K inhibitor LY294002. ResultsThe Mixture significantly alleviated asthma symptoms, decreased IgE levels, cytokine levels (IL-4, IL-5, IL-13 and TNF-α), and the number of inflammatory cells in serum or bronchoalveolar lavage fluid (BALF), leading to the alleviation of lung pathological lesions. Additionally, the Mixture reduced the expression of Bax and Caspase-3 while increasing Bcl-2 expression, resulting in mitigated apoptosis in lung tissue. Furthermore, there appeared a decrease in the levels of PI3K and p-PI3K, as well as the ratio of p-Akt to Akt in the Mixture group, indicating the suppression of PI3K and Akt phosphorylation. Interestingly, the effects of the Mixture were comparable to those of GPH, LY294002, or the combination of LY294002 with the Mixture. ConclusionThe study confirms that the Mixture containing luteolin, arbutin, and marmesin indeed alleviates allergic asthma induced by OVA in mice by suppressing the PI3K/Akt signaling pathway. These findings highlight the potential of the GPH-derived Mixture as a novel therapeutic for the treatment of allergic asthma.

Spleen aminopeptides (FUKETUO) elevate the therapeutic effect of house dust mite desensitization on allergic asthma by inducing interleukin-10 positive regulatory T cells (IL-10+ Tregs) expression.

As a novel immunomodulator, spleen aminopeptides (FUKETUO) can correct the imbalance of immune cells and elevate their functions. Spleen aminopeptides have been used in the treatment of respiratory diseases. However, the regulatory mechanism of it on allergic asthma and desensitization has not been reported, further study is critically needed. This study aimed to investigate the effect and mechanism of spleen aminopeptides on allergic asthma and desensitization. We established an allergic asthma model by house dust mite (HDM) with/without desensitization treatment. The allergic asthma mouse model was established with HDM and treated with desensitization and increasing dose of spleen aminopeptides according to different immune phases. Pathological markers such as airway hyper-responsiveness, and cell composition were monitored to determine the effectiveness of treatment. Spleen aminopeptides can promote the proportion of interleukin-10 positive (IL10+) allergen-specific regulatory T cells (Tregs), and further promote interleukin-10 (IL-10) expression in desensitization. They alleviated the allergic symptoms and elevated desensitization, decreased airway hyper-reaction and lung tissue injury, reduced specific immunoglobulin E (IgE) in serum, eosinophil number and interleukin-4 (IL-4) expression in bronchoalveolar lavage fluid (BALF), therefore, being able to control allergic asthma. Our results suggested that spleen aminopeptides (FUKETUO) could elevate the expression of (CD4+CD25+IL10+) Tregs, especially when it co-immunized with desensitization. Thereby, FUKETUO improved the efficacy of desensitization, and inhibited the development of allergic asthma.

Anti-Allergic and Anti-Inflammatory Effects of Lidocaine-Derived Organic Compounds in a House Dust Mite-Induced Allergic Rhinitis Mouse Model.

Allergic rhinitis (AR) is a common chronic disease that significantly impacts the quality of life. Lidocaine is known to have anti-inflammatory and immunomodulatory effects. This study evaluated the effect of lidocaine analogs in a Dermatophagoides pteronyssinus (DP)-induced AR mouse model. An AR model was developed using BALB/c mice via intraperitoneal sensitization with DP and intranasal challenge with DP. One hour before stimulation with DP, lidocaine analogs, EI137 and EI341 (at a dose of 0.5 or 5 ug/g), were administered intranasally. Nasal symptoms and serum total IgE, interleukin (IL)-4, IL-10, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α levels were evaluated. Reverse-transcription polymerase chain reaction was used to determine IL-4, IL-10, and IFN-γ, as well as the expression of their mRNA transcription factors in the sinonasal mucosa. Histologic changes were evaluated using hematoxylin and eosin and periodic acid-Schiff staining. The DP-induced AR mouse model had increased serum levels of total IgE and cytokines. EI137 and EI341 significantly suppressed the levels of total IgE, IL-4, and TNF-α. Intranasal instillation of EI137 and EI341 significantly inhibited IL-4, IL-10, and IFN-γ mRNA expression, as well as inflammatory cells and mucus-producing goblet cells. Lidocaine analogs also suppressed DP-stimulated IL-4, IFN-γ, and IFN-γ production by splenocytes. Intranasal instillation of EI137 and EI341 exhibited anti-allergic and anti-inflammatory effects, influenced by Th1 and Th2 inflammatory cytokines. These lidocaine analogs suppressed DP-induced sinonasal mucosal inflammation, inflammatory cell infiltration, and mucus hypersecretion.

A comparison of the physicochemical properties, allergenicity, and stability of recombinant β-lactoglobulin: Development of standard bovine milk allergens

Bovine milk is one of the eight major allergenic foods identified by WHO/FAO, and β-lactoglobulin (BLG) is the primary allergen. Allergen standardization is very important for the diagnosis of milk allergy, and recombinant protein preparation is a promising method. In this study, BLG with high soluble expression was prepared by a method based on Escherichia coli. To verify the feasibility of recombinant BLG, the difference in physicochemical properties, allergenicity, and stability were investigated. Recombinant and natural BLG both had a size of approximately 230 nm with a zeta potential of −50 mV, indicating that they share the similar solubility and colloidal properties. Additionally, allergic mice model results confirmed that recombinant BLG showed comparable ability in stimulating antibody production, Th2 cytokine release, and cellular immunity compared with natural BLG. Then, the thermal stability of BLG was studied using spectrum analysis within the range of 25–85 °C. Recombinant BLG showed satisfactory thermal stability, the concentration, protein structure and IgG binding capacity changed obviously until temperature reached at 55 °C, although natural BLG is more heat resistant. After 28 days storage at 4 °C in the form of lyophilized powder, there was no significant change in the content of recombinant and natural BLG. In summary, the physicochemical properties, allergenicity, and stability of recombinant BLG were comparable to those of natural BLG. This study provides theoretical reference for the development of standard bovine allergen, and it is expected that recombinant allergen can be used in the research and diagnosis of bovine milk allergy.

Targeted inhibition of m6A demethylase FTO by FB23 attenuates allergic inflammation in the airway epithelium.

Epithelial cells play a crucial role in asthma, contributing to chronic inflammation and airway hyperresponsiveness. m6A modification, which involves key proteins such as the demethylase fat mass and obesity-associated protein (FTO), is crucial in the regulation of various diseases, including asthma. However, the role of FTO in epithelial cells and the development of asthma remains unclear. In this study, we investigated the demethylase activity of FTO using a small-molecule inhibitor FB23 in epithelial cells and allergic inflammation invivo and invitro. We examined the FTO-regulated transcriptome-wide m6A profiling by methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA-seq under FB23 treatment and allergic inflammation conditions. Immunofluorescence staining was performed to assess the tissue-specific expression of FTO in asthmatic bronchial mucosa. We demonstrated that FB23 alleviated allergic inflammation in IL-4/IL-13-treated epithelial cells and house dust mite (HDM)-induced allergic airway inflammation mouse model. The demethylase activity of FTO contributed to the regulation of TNF-α signaling via NF-κB and epithelial-mesenchymal transition-related pathways under allergic inflammation conditions in epithelial cells. FTO was expressed in epithelial, submucosal gland, and smooth muscle cells in human bronchial mucosa. In conclusion, FB23-induced inhibition of FTO alleviates allergic inflammation in epithelial cells and HDM-induced mice, potentially through diverse cellular processes and epithelial-mesenchymal transition signaling pathways, suggesting that FTO is a potential therapeutic target in asthma management.

Exploration of Potential Targets and Molecular Mechanisms of the Yiqi Jianpi Tongqiao Formula in Treating Allergic Rhinitis Mouse Model based on Network Pharmacology and Molecular Docking.

To investigate the therapeutic effect of Yiqi Jianpi Tongqiao (YJT) formula (Hedysarum Multijugum Maxim, Magnoliae Flos, Xanthii Fructus, Notopterygii Rhizoma Et Radix, Kaempferiae Rhizoma, Acoritataninowii Rhizoma, Saposhnikoviae Radix) on an allergic rhinitis mouse model, and to explore the active ingredients, key targets, and molecular mechanisms of this formula using network pharmacology and molecular docking methods. An allergic rhinitis mouse model was established to observe changes in rhinitis symptoms, nasal mucosal morphology, and serum indicators after administering the YJT formula. The TCMSP, GeneCards, OMIM, and DisGeNET databases were used to screen for the active ingredients, action targets, and disease targets of the YJT formula. The Cytoscape software was used to construct a network of the active ingredients and action targets. The protein-protein interaction (PPI) network was used to predict hub genes. The corresponding active compounds with the hub genes' highest oral bioavailability (OB) values were identified, followed by molecular docking analysis. Animal experiments demonstrated that the YJT formula reduced rhinitis symptoms (nasal itching, runny nose, and face scratching) in allergic rhinitis mice, as well as decreased nasal mucosal inflammatory reactions and serum inflammatory indicators (histamine, OVAspecific IgE, IL-1β levels). Furthermore, 63 active components and 101 potential indicator targets of the YJT formula were identified, along with 5 hub genes (IL6, AKT1, IL1B, VEGFA, and PTGS2), and the corresponding active compounds with the highest OB values were quercetin, aloe-emodin, and denudanolide b. Molecular docking results revealed the binding energy between quercetin, aloe-emodin, denudanolide b and 5 hub genes (IL6, AKT1, IL1B, VEGFA, and PTGS2) were -5.78 to -10.22 kcal/mol, the binding energy between dexamethasone and 5 hub genes were -6.3 to -9.7 kcal/mol. In addition, GO and KEGG analysis suggested significant enrichment of these genes in biological processes such as response to lipopolysaccharide, response to molecule of bacterial origin, and response to reactive oxygen species, as well as signaling pathways like AGE-RAGE signaling pathway in diabetic complications, Lipid and atherosclerosis, and IL-17 signaling pathway. The YJT formula has therapeutic effects in an allergic rhinitis mouse model, with the main active components being quercetin, aloe-emodin, and denudanolide b, and the key targets being IL6, AKT1, IL1B, VEGFA, and PTGS2, involving multiple signaling pathways.

Aspalathin, a Primary Rooibos Flavonoid, Alleviates Mast Cell-Mediated Allergic Inflammation by the Inhibition of FcεRI Signaling Pathway.

Mast cells are primary cells initiating allergic inflammation by the release of various allergic mediators, such as histamine and pro-inflammatory cytokines. Aspalathin (ASP) is the predominant flavonoid found exclusively in rooibos, an herb that has been traditionally used in allergy relief therapy. In the present study, we investigated the beneficial effects of ASP on mast cell-mediated allergic inflammation. For in vivo study, two well-known mast cell-mediated local and systemic allergic inflammation mouse models were used: passive cutaneous anaphylaxis (PCA) and active systemic anaphylaxis mouse models (ASA). Oral administration of ASP dose-dependently suppressed immunoglobulin (Ig)E-mediated PCA responses evidenced by Evans blue extravasation, ear thickening, and mast cell degranulation. ASP also significantly mitigated ovalbumin-induced ASA responses, including hypothermia, histamine secretion, and the production of IgE and interleukin-4. Notably, ASP was more effective in suppressing allergic inflammation than nothofagin, another prominent flavonoid known as an anti-allergic component of rooibos. The regulatory mechanism of mast cell activation by ASP was clarified using mast cell line and primary cultured mast cells (RBL-2H3 and mouse bone marrow-derived mast cells). ASP reduced IgE-stimulated mast cells degranulation and intracellular calcium influx by the inhibition of FcεRI signaling pathway (Lyn, Fyn, and Syk). Moreover, ASP reduced pro-inflammatory cytokine expressions by inhibiting two major transcription factors, nuclear factor of activated T cells and nuclear factor-κB. Collectively, we proposed that ASP could be a potential therapeutic candidate for the treatment of mast cell-mediated allergic inflammatory diseases.

Foxp3+ Treg control allergic skin inflammation by restricting IFN-γ-driven neutrophilic infiltration and NETosis

BackgroundAtopic dermatitis (AD), a chronic inflammatory skin disease with T cell activation as a key feature, in which Th2 cell–mediated responses play a pivotal role. Regulatory T cells (Treg) are central immune cells that restrict autoimmunity and inflammation in the body. Patients with immune dysregulation, polyendocrinopathy, or enteropathy X-linked syndrome, an immune disease characterized by a deficiency in Treg, develop skin inflammation and allergic disorders, indicating that Treg play a crucial role in the development of allergic skin inflammation. Objectivewe investigated the underlying mechanisms by which Treg control cutaneous allergic inflammation. MethodsAn allergic skin inflammation mouse model was constructed using MC903, and Treg-depleted mouse model was constructed using diphtheria toxin. Neutralization of IFN-γ was constructed using anti-mouse-IFN-γ mouse antibody. Neutrophil infiltration was analyzed by flow cytometry and immunohistochemistry. Neutrophil extracellular traps (NETs), a process called NETosis, were detected using immunofluorescence. In vitro neutrophil stimulation and immunocytochemistry was conducted to demonstrate the effect of IFN-γ on NETosis. ResultsThe depletion of Foxp3+ Treg led to significantly exacerbated AD-like skin inflammation, including increased recruitment of neutrophils and expression of Th1 cytokine IFN-γ. Neutrophil infiltrating in skin of Treg-depleted mice released more NETs than wild type. Neutralization of IFN-γ abolished neutrophil infiltration and NETosis in Treg-depleted mice. Neutrophils stimulated with IFN-γ were more prone to release NETs in vitro. Finally, Foxp3+ Treg control cutaneous allergic inflammation by regulating IFN-γ-driven neutrophilic infiltration and NETosis. ConclusionOur results highlight the previously underestimated Treg-IFN-γ-neutrophil inflammatory axis.

The bioflavonoid hispidulin effectively attenuates T helper type 2-driven allergic lung inflammation in the ovalbumin-induced allergic asthma mouse model

BackgroundAllergic asthma affects nearly 300 million people worldwide and causes ahigh burden of disability and death. Effective treatments rely heavily on corticosteroids, which are associated with various complications. So, the alternative treatment is of significance. Hispidulin is a bioflavonoid found in herbs that were used in traditional medicine to treat inflammatory diseases, including asthma. This study aims to investigate the efficacy of hispidulin compound in the treatment of allergic lung inflammation using the mouse model of allergic asthma. MethodsBALB/c mice were sensitized and challenged with chicken egg ovalbumin. Cells and cytokines from bronchoalveolar lavage (BAL) fluid were examined. Lung tissues were collected for histologic study. Mouse splenic CD4+ cells were cultured to observe the effect of hispidulin on T-helper 2 (Th2) cell differentiation in vitro. ResultsHispidulin treatment could alleviate allergic airway inflammation as evidenced by a significant reduction in the inflammatory cell count and Th2 cytokines interleukin (IL)-4, IL-5, IL-13 in BAL fluid. Histologic examination of lung tissues revealed lower inflammatory cell infiltration to the bronchi and less airway goblet cell hyperplasia in the treatment group compared to the control group. At the cellular level, hispidulin (25, 50, and 100 μM) was found to directly suppress the differentiation and proliferation of Th2 cells and to suppress the production of Th2 cytokines, such as IL-4, IL-5, and IL-13, in vitro. ConclusionsHispidulin treatment was shown to effectively decrease type 2 lung inflammation in an ovalbumin-induced allergic asthma mouse model by directly suppressing Th2 cell differentiation and functions.

Quercetin-crosslinked chitosan nanoparticles: a potential treatment for allergic rhinitis

Allergic rhinitis (AR) remains a major health problem worldwide. Compared with traditional oral drugs, nasal administration avoids first-pass metabolism and achieve faster and more effective efficacy. In this study, we used the ion crosslinking method to prepare quercetin–chitosan nasal adaptive nanomedicine (QCS) delivery system and evaluated in the treatment of allergic rhinitis mice models. The obtained positively charged nanoparticles with a particle size of 229.2 ± 0.2 nm have excellent characteristics in encapsulation efficiency (79.604%), drug loading rate (14.068%), drug release (673.068 μg) and stability(> 7 days). Excitingly, QCS treatment significantly reduced the number of sneezing and nasal rubbing events in AR mice, while reducing the levels of inflammatory factors such as immunoglobulin E (IgE), interleukin (IL)-17, tumor necrosis factor (TNF)-α, and (IL)-6 to alleviate AR symptoms. Hematoxylin–eosin (HE) staining also showed the damaged nasal mucosa was improved. These experimental results suggest that QCS can effectively suppress allergic inflammation in a mouse model and hold promise as a therapeutic option for allergic rhinitis.

In vivo low-dose phase-contrast CT for quantification of functional and anatomical alterations in lungs of an experimental allergic airway disease mouse model.

Synchrotron-based propagation-based imaging (PBI) is ideally suited for lung imaging and has successfully been applied in a variety of in vivo small animal studies. Virtually all these experiments were tailored to achieve extremely high spatial resolution close to the alveolar level while delivering high x-ray doses that would not permit longitudinal studies. However, the main rationale for performing lung imaging studies in vivo in small animal models is the ability to follow disease progression or monitor treatment response in the same animal over time. Thus, an in vivo imaging strategy should ideally allow performing longitudinal studies. Here, we demonstrate our findings of using PBI-based planar and CT imaging with two different detectors-MÖNCH 0.3 direct conversion detector and a complementary metal-oxide-semiconductor (CMOS) detector (Photonics Science)-in an Ovalbumin induced experimental allergic airway disease mouse model in comparison with healthy controls. The mice were imaged free breathing under isoflurane anesthesia. At x-ray dose levels below those once used by commercial small animal CT devices at similar spatial resolutions, we were able to resolve structural changes at a pixel size down to 25 μm and demonstrate the reduction in elastic recoil in the asthmatic mice in cinematic planar x-ray imaging with a frame rate of up to 100 fps. Thus, we believe that our approach will permit longitudinal small animal lung disease studies, closely following the mice over longer time spans.

Mesenchymal Stromal Cell Therapy Alleviates Ovalbumin-Induced Chronic Airway Remodeling by Suppressing M2 Macrophage Polarization.

Chronic asthma is characterized by airway hyperresponsiveness, inflammation, and remodeling. Previous studies have shown that mesenchymal stromal/stem cells (MSCs) exert anti-inflammatory effects on asthma via regulation of the immune cells. However, the therapeutic mechanism of MSCs, especially the mechanism of airway remodeling in chronic asthma, remains to be elucidated. Here, we aimed to investigate the therapeutic effect of MSCs on airway remodeling in chronic asthma and explored the mechanisms by analyzing the polarization phenotype of macrophages in the lungs. We established a mouse model of chronic asthma induced by ovalbumin (OVA) and evaluated the effect of MSCs on airway remodeling. The data showed that MSCs treatment before the challenge exerted protective effects on OVA-induced chronic asthma, i.e., decreased the inflammatory cell infiltration, Th2 cytokine levels, subepithelial extracellular matrix deposition, and transforming growth factor β (TGF-β)/Smad signaling. Additionally, we found that MSCs treatment markedly suppressed macrophage M2 polarization in lung tissue. At the same time, MSCs treatment inhibited NF-κB p65 nuclear translocation, ER stress, and oxidative stress in the OVA-induced chronic allergic airway remodeling mice model. In conclusion, these results demonstrated that MSCs treatment prevents OVA-induced chronic airway remodeling by suppressing macrophage M2 polarization, which may be associated with the dual inhibition of ER stress and oxidative stress. This discovery may provide a new theoretical basis for the future clinical application of MSCs.

Mesenchymal Stem Cell-derived Exosome; An Interesting Nanocarrier to Improve Allergen-specific Intranasal Immunotherapy.

Increasing the efficacy of allergen-specific intranasal immunotherapy (INIT) has recently been the main goal of several studies to establish this route as a safe delivery method through mucosal pathways. In this case, the present study evaluated the potential of INIT using ovalbumin (OVA)-loaded mesenchymal stromal/stem cell (MSC)-derived exosomes (Exo-OVA) in an allergic asthma mouse model. Together with control groups, sensitized Balb/c mice underwent intranasal immunotherapy with Exo-OVA (10 μg OVA per dose) for three consecutive weeks. Serum-specific immunoglobulin E (IgE) levels, transforming growth factor-beta (TGF-β), interleukin (IL)-4, and interferon-gamma (IFN-γ) production by cultured spleen cells, lung histopathologic analysis, and nasopharyngeal lavage fluid cellular examinations were then conducted. The results showed that INIT using Exo-OVA significantly increased IFN-γ and TGF-β secretion, while allergen-specific IgE and IL-4 production were dramatically decreased compared to the control group receiving phosphate-buffered saline. In addition, the eosinophil and total cell counts in the nasopharyngeal lavage fluid were reduced, and inflammatory conditions and cell accumulation in lung tissue were ameliorated. In conclusion, the Exo-OVA improved the INIT efficacy compared to free OVA. Therefore, this formulation could be introduced as an effective approach for immunomodulatory purposes with a shorter treatment duration and reduced side effects.

Comparative analysis of tropomyosin allergenicity in three different species of molluscs: insights into the role of amino acid composition in IgE epitopes.

Limited research has been conducted on the differences in allergenicity among Alectryonella plicatula tropomyosin (ATM), Haliotis discus hannai tropomyosin (HTM), and Mimachlamys nobilis tropomyosin (MTM) in molluscs. Our study aimed to comprehensively analyze and compare their immunoreactivity, sensitization, and allergenicity while simultaneously elucidating the underlying molecular mechanisms involved. We assessed the immune binding activity of TM utilizing 86 sera from allergic patients and evaluated sensitization and allergenicity through two different types of mouse models. The dot-blot and basophil activation test assays revealed strong immunoreactivity for HTM, ATM, and MTM, with HTM exhibiting significantly lower levels compared to ATM. In the BALB/c mouse sensitization model, all TM groups stimulated the production of specific antibodies, elicited IgE-mediated immediate hypersensitivity responses, and caused an imbalance in the IL-4/IFN-γ ratio. Similarly, in the BALB/c mouse model of food allergy, all TM variants induced IgE-mediated type I hypersensitivity responses, leading to the development of food allergies characterized by clinical symptoms and an imbalance in the IL-4/IFN-γ ratio. The stimulation ability of sensitization and the severity of food allergies consistently ranked as ATM > MTM > HTM. Through an in-depth analysis of non-polar amino acid frequency and polar hydrogen bonds, HTM exhibited higher frequencies of non-polar amino acids in its amino acid sequence and IgE epitopes, in comparison with ATM and MTM. Furthermore, HTM demonstrated a lower number of polar hydrogen bonds in IgE epitopes. Overall, HTM exhibited the lowest allergenic potential in both allergic patients and mouse models, likely due to its lower polarity in the amino acid sequence and IgE epitopes.

Recombinant Art v4.01 protein produces immunological tolerance by subcutaneous immunotherapy in a wormwood pollen-driven allergic asthma female mouse model.

Art v4.01 is a well-known profilin protein belonging to the pan-allergens group and is commonly involved in triggering allergic asthma, polyallergy, and cross-sensitization. It is also referred to as Wormwood due to its origin. Crude wormwood extracts are applied for allergen-specific immunotherapy (AIT). Whether the recombinant Art v4.01 (rArt v4.01) can produce in vivo immunological tolerance by subcutaneous immunotherapy (SCIT) remains elusive. In this study, to investigate the in vivo immunological response of rArt v4.01, Th2, Th1, Treg, Th17 type-related cytokines and phenotypes of immune cells were tested, facilitating the exploration of the underlying mechanisms. The expression and purification of Art v4.01 were carried out using recombinant techniques. Allergic asthma female BALB/c mice were induced by subcutaneous sensitization of wormwood pollen extract and intranasal challenges. SCIT without adjuvant was performed using the rArt v4.01 and wormwood pollen extract for 2 weeks. Following exposure to challenges, the levels of immunoglobulin E (IgE), cytokines, and inflammatory cells were assessed through enzyme-linked immunosorbent assay (ELISA) and histological examination of sera, bronchoalveolar lavage fluid (BALF), and lung tissue. These parameters were subsequently compared between treatment groups receiving rArt v4.01 and wormwood pollen extract. The rArt v4.01 protein was expressed, which had a high purity (>90%) and an allergenic potency. Compared with the pollen extract, rArt v4.01 was superior in terms of reducing the number of white blood cells (WBCs), total nucleated cells (TNCs), and monocytes (MNs) in BALF and the degree of lung inflammation (1.77±0.99 vs. 2.31±0.80, P > 0.05). Compared with the model group, only rArt v4.01 reduced serum IgE level (1.19±0.25 vs. 1.61±0.17 μg/ml, P = 0.062), as well as the levels of Th2 type-related cytokines (interleukin-4 (IL-4) (107.18±16.17 vs. 132.47±20.85 pg/ml, P < 0.05) and IL-2 (19.52±1.19 vs. 24.02±2.14 pg/ml, P < 0.05)). The study suggested that rArt v4.01 was superior to pollen extract in reducing the number of inflammatory cells in BALF, pneumonitis, levels of pro-inflammatory cytokines, and serum IgE level. These findings confirmed that Art v4.01 could be a potential candidate protein for allergen-specific immunotherapy.

Adaptive plasticity of natural interleukin-35-induced regulatory T cells (Tr35) that are required for T-cell immune regulation.

Background: IL-35 potently inhibits immune responses both in vivo and in vitro. However, the specific characteristics of IL-35-producing cells, including their developmental origin, cellular phenotype, and function, are unknown. Methods: By using a novel IL-35 reporter mouse (Ebi3-Dre-Thy1.1) and double transgenic fate-mapping reporter mice (35EbiT-Rosa26-rox-tdTomato reporter mice or Foxp3 fate-mapping system), we tracked and analyzed the differentiation and developmental trajectories of Tr35 cells in vivo. And then we investigated the therapeutic effects of OVA-specific Tr35 cells in an OVA-induced allergic airway disease model. Results: We identified a subset of cells, denoted Tr35 cells, that secrete IL-35 but do not express Foxp3. These cells have high expression of molecules associated with T-cell activation and can inhibit T-cell proliferation in vitro. Our analyses showed that Tr35 cells are a distinct subpopulation of cells that are independent of Tr1 cells. Tr35 cells exhibit a unique gene expression profile and tissue distribution. The presence of Thy1.1 (Ebi3) expression in Tr35 cells indicates their active secretion of IL-35. However, the proportion of ex-Tr35 cells (Thy1.1-) is significantly higher compared to Tr35 cells (Thy1.1+). This suggests that Tr35 cells possess the ability to regulate IL-35 expression rapidly in vivo. Tr35 cells downregulated the expression of the inflammatory cytokines IL-4, IFN-γ and IL-17A. However, once Tr35 cells lost IL-35 expression and became exTr35 cells, the expression of inflammatory cytokines was upregulated. Importantly, our findings indicate that Tr35 cells have therapeutic potential. In an OVA-induced allergic airway disease mouse model, Tr35 cell reinfusion significantly reduced airway hyperresponsiveness and histopathological airway and lung inflammation. Conclusions: We have identified a subset of Tregs, Tr35 cells, that are distinct from Tr1 cells. Tr35 cells can dynamically regulate the secretion of inflammatory cytokines by controlling IL-35 expression to regulate inflammatory immune responses.