Immunologic Basis of Type 2 Biologics for Severe Asthma

Carvacrol in asthma management: a comprehensive review of its therapeutic potential and mechanisms of action

Asthma, a chronic inflammatory disorder of the airways, remains a significant global health concern. Current treatments focus on symptom management and inflammation control, but the search for more effective and safer therapies continues. Carvacrol, a naturally occurring monoterpenoid phenol found in essential oils of various plants, has emerged as a promising bioactive compound with potent anti-inflammatory, antioxidant, and bronchodilatory properties. This review explores the potential of carvacrol as a novel therapeutic agent for asthma management. We discuss its mechanisms of action, including modulation of inflammatory pathways, inhibition of oxidative stress, and relaxation of bronchial muscles. Additionally, preclinical and clinical studies evaluating the efficacy and safety of carvacrol in asthma treatment are analyzed. The integration of carvacrol into existing treatment regimens could offer a multifaceted approach to asthma management, enhancing therapeutic outcomes and improving patients' quality of life.

Solasodine inhibits the Th2 immune response and airway remodeling in asthmatic mice through the Runx3/NLRP3 pathway

PURPOSE

To explore the therapeutic effects of Solasodine on Th2 immune responses and airway remodeling, and to assess whether its mechanism involves NLRP3 inflammasome inactivation mediated by Runx3.

METHODS

We created an asthma model with wild-type and Runx3 knockout mice using ovalbumin (OVA). After oral administration of Solasodine, we assessed inflammatory and Th2 immune responses using HE staining, ELISA, and flow cytometry. Airway remodeling was assessed with Masson's trichrome staining and α-SMA and TGF-β immunohistochemistry. Mucus secretion was analyzed through MUC5AC immunohistochemistry, and expectoration assays. We studied NLRP3 inflammasome activation using immunohistochemistry and Western blot. We used western blotting and flow cytometry to evaluate how Solasodine regulates Runx3 protein levels.

RESULTS

Solasodine effectively inhibited the inflammatory response in OVA-induced asthmatic mice, evidenced by reducing inflammatory cell infiltration and lower IL-4, IL-5, and IL-13 levels, decreasing airway remodeling and mucus secretion. Solasodine reduced airway hyperresponsiveness, shown by a lower Penh value. Solasodine boosts Runx3 expression and suppresses NLRP3 inflammasome activation in asthmatic mice. We created an asthma model in Runx3 knockout mice and administered Solasodine at a consistent dose. Following OVA induction, Runx3 knockout mice showed greater inflammation, a Th2 immune response, airway remodeling, and mucus secretion than wild-type mice. Solasodine is less effective in Runx3 knockout asthmatic mice than in wild-type mice.

CONCLUSION

The anti-asthmatic effects of Solasodine are shown through the inhibition in the Th2 immune response, airway remodeling, hyperresponsiveness, and mucus secretion. The effectiveness may be linked to Runx3-mediated the NLRP3 inflammasomes.

NLRP3 regulates ferroptosis via the JAK2/STAT3 pathway in asthma inflammation: Insights from in vivo and in vitro studies

BACKGROUND

Ferroptosis, an iron-dependent form of cell death, plays a pivotal role in the pathologic progression of asthma. Electroacupuncture (EA) has demonstrated considerable efficacy in mitigating asthma airway inflammation, although its underlying mechanisms remain partially elucidated.

METHODS

We investigated the regulatory effect of NLRP3 on ferroptosis using a lipopolysaccharide (LPS)-induced inflammation model in BEAS-2B cells, where NLRP3 expression was modulated with si-RNA and overexpression plasmids. The levels of inflammatory cytokines TNF-α, IL-1β, and IL-6 were quantified. We also assessed NLRP3 and JAK2/STAT3 pathway-related proteins, and evaluated lipid peroxidation, mitochondrial membrane potential (ΔΨm), and antioxidant system functionality. In vivo, we examined the impact of EA on ferroptosis and airway inflammation by modulating NLRP3 activation. Asthma inflammation severity was evaluated using H&E, Masson, and PAS staining, alongside ELISA. NLRP3 and JAK2/STAT3 pathway-related proteins, as well as ferroptosis indicators, were also analyzed. The mechanism by which NLRP3 activates ferroptosis was investigated through in vitro assays.

RESULTS

LPS exposure resulted in increased intracellular inflammatory cytokines, and activation of the NLRP3 and JAK2/STAT3 pathways, leading to enhanced lipid peroxidation, decreased ΔΨm, and disruption of antioxidant system balance, ultimately inducing ferroptosis. Si-NLRP3 countered the effects of LPS, whereas oe-NLRP3 exacerbated symptoms. In vivo studies revealed that EA reduced airway inflammation, inhibited NLRP3 activation, and decreased phosphorylation of JAK2/STAT3, effectively lowering ferroptosis-related indicators. Utilizing JAK2/STAT3 activators and inhibitors, we confirmed that NLRP3 mediates ferroptosis via the JAK2/STAT3 pathway.

CONCLUSIONS

EA alleviates HDM-induced asthma, primarily through the inhibition of NLRP3 activation, which modulates the JAK2/STAT3 pathway and mediates ferroptosis.

Association between specific IgE to staphylococcal enterotoxin B and the eosinophilic phenotype of asthma

BACKGROUND/AIMS

Sensitization to staphylococcal superantigens (SAgs) could contribute to asthma severity. However, its relevance with eosinophilic phenotype has not yet been clarified. This study aimed to investigate associations between serum specific IgE levels to SAg and eosinophilic airway inflammation in adult asthmatics.

METHODS

The serum specific IgE levels to 3 SAgs, including staphylococcal enterotoxin A (SEA) and B (SEB), and toxic shock syndrome toxin-1 (TSST-1) were measured by ImmunoCAP in 230 adult asthmatic patients and 50 healthy controls (HCs). Clinical characteristics and laboratory parameters, including serum total/free IgE, and 2 eosinophil-activation markers, eosinophil cationic protein (ECP), and eosinophil-derived neurotoxin (EDN), were analyzed according to blood eosinophil counts (BEC; 150 cells/μL) and serum specific IgE levels to 3 SAgs (0.35 kU/L).

RESULTS

Asthmatic patients showed higher serum specific IgE levels to 3 SAgs than HCs (p < 0.05 for all). The serum total/clinfree IgE levels were significantly higher in asthmatics with positive IgE responses to 3 SAgs than those without (p < 0.05 for all). There were no significant differences in clinical parameters including age, asthma severity, comorbidities, or smoking according to IgE responses to 3 SAgs. Patients with positive IgE responses to SEB (not to SEA/TSST-1) had higher serum specific IgE levels to house dust mites and ECP/EDN as well as higher BEC with positive correlations between serum SEB-specific IgE levels and BEC/ECP/EDN (p < 0.05 for all).

CONCLUSION

These findings suggest that serum SEB-specific IgE levels could contribute to eosinophil activation as well as IgE production in adult asthma.

Effects of Panax species and their bioactive components on allergic airway diseases

Panax species include Panax ginseng Meyer, Panax quinquefolium L., Panax notoginseng, Panax japonicum, Panax trifolium, and Panax pseudoginseng, which contain bioactive components (BCs) such as ginsenosides and polysaccharides. Recently, growing evidence has revealed the pharmacological effects of Panax species and their BCs on allergic airway diseases (AADs), including allergic asthma (AA) and allergic rhinitis (AR). AADs are characterized by damaged epithelium, sustained acquired immune responses with enforced Th2 responses, allergen-specific IgE production, and enhanced production of histamine and leukotrienes by activated mast cells and basophils. In this review, we summarize how Panax species and their BCs modulate acquired immune responses involving interactions between dendritic cells and T cells, reduce the pro-inflammatory responses of epithelial cells, and reduce allergenic responses from basophils and mast cells in vitro. In addition, we highlight the current understanding of the alleviative effects of Panax species and their BCs against AA and AR in vivo. Moreover, we discuss the unmet needs of research and considerations for the treatment of patients to provide basic scientific knowledge for the treatment of AADs using Panax species and their BCs.

Mitochondria protective and anti-apoptotic effects of peripheral benzodiazepine receptor and its ligands on the treatment of asthma in vitro and vivo

BACKGROUND

Asthma is a prevalent respiratory inflammatory disease. Abnormal apoptosis of bronchial epithelial cells is one of the major factors in the progression of asthma. Peripheral benzodiazepine receptors are highly expressed in bronchial epithelial cells, which act as a component of the mitochondrial permeability transition pore to regulate its opening and closing and apoptosis of bronchial epithelial cells. We aimed to investigate the mechanisms by which peripheral benzodiazepine receptor and its ligands, agonist 4'-Chlorodiazepam (Ro5-4864) and antagonist 1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxamide (PK 11,195), modulate the mitochondrial function and cell apoptosis in the treatment of asthma.

METHODS

In vitro study, Ro5-4864 and PK 11,195 were utilized to pretreat cells prior to the inflammatory injury induced by Lipopolysaccharide. The reactive oxygen species, the apoptosis of cell, the mitochondrial membrane potentials, the ultrastructures of the mitochondria and the expression levels of peripheral benzodiazepine receptors and apoptosis-related proteins and genes were detected. In vivo study, mice were administrated intraperitoneally with Ro5-4864 and PK 11,195 before sensitized and challenged by ovalbumin. Serum IgE and bronchoalveolar lavage fluid cytokines were detected, and lung tissues were underwent the histopathological examination.

RESULTS

The ligands of peripheral benzodiazepine receptor counteracted the effects of the increase of reactive oxygen species, the elevated extent of apoptosis, the decrease of mitochondrial membrane potentials and the disruption of mitochondrial ultrastructures induced by Lipopolysaccharide. The ligands also promoted the expression of anti-apoptosis-related proteins and genes and inhibited the expression of pro-apoptosis-related proteins and genes. Besides, the ligands reduced the levels of serum IgE and bronchoalveolar lavage fluid cytokines in asthmatic mice and attenuated the histopathological damage of lungs.

CONCLUSION

Peripheral benzodiazepine receptor serves as a potential therapeutic target for the treatment of asthma, with its ligands exerting mitochondrial protective and anti-apoptotic effects on bronchial epithelial cells.

Engineering bispecific T-cell engagers to deplete eosinophils for the treatment of severe eosinophilic asthma

Severe eosinophilic asthma (SEA) is characterized by elevated eosinophil counts in the blood and airway mucosa. While monoclonal antibody therapies targeting interleukin-5 (IL-5) and its receptor (IL-5Rα) have improved treatment, some patients remain unresponsive. We propose an alternative approach to eliminate eosinophils using T cells by engineering IL-5Rα × CD3 bispecific T-cell engagers (bsTCEs) that target both IL-5Rα on eosinophils and CD3 on T cells. We designed different formats of IL-5Rα × CD3 bsTCEs, incorporating variations in valency, geometry, and affinity for the target antigen binding. We identified the single-chain variable fragment (scFv)-Fc format with the highest affinity toward the membrane-proximal domain of IL-5Rα in the IL-5Rα-binding arm showed the most potent cytotoxicity against IL-5Rα-expressing peripheral eosinophils by activating autologous primary T cells from healthy donors. This study proposes IL-5Rα × CD3 bsTCEs as potential alternatives for SEA treatment. Importantly, it demonstrates the first application of bsTCEs in eliminating disease-associated cells, including eosinophils, beyond cancer cells.

Bacterial Extracellular Vesicles: A Candidate Molecule for the Diagnosis and Treatment of Allergic Diseases

Extracellular vesicles (EVs) are an end product released from almost all living cells such as eukaryotic cells and bacteria. These membrane vesicles containing proteins, lipids, and nucleic acids are mainly involved in intracellular communications through the transfer of their components from donor to acceptor cells. Moreover, EVs have been implicated in many functions in response to environmental changes, contributing to health and disease; bacterial EVs depending on their specific parental bacterium have diverse effects on immune responses to play a beneficial or pathogenic role in patients with various allergic and immunologic diseases. As bacterial EVs are a completely new area of investigation in this field, we highlight our current understanding of bacterial EVs and discuss their diagnostic and therapeutic potentials (as immunomodulators) for targeting asthma and atopic dermatitis.