Desloratadine citrate disodium injection, a potent histamine H(1) receptor antagonist, inhibits chemokine production in ovalbumin-induced allergic rhinitis guinea pig model and histamine-induced human nasal epithelial cells via inhibiting the ERK1/2 and NF-kappa B signal cascades

Effectiveness of selective NaV1.7 blocker PF-05089771 in reducing cough associated with allergic rhinitis in guinea pigs

BACKGROUND

Allergic rhinitis (AR) is a common cause of chronic cough, linked to dysregulated airway C- and Aδ-fibres through inflammatory mediators. Despite the limited efficacy of current antitussive therapies, recent studies show that the NaV1.7 inhibitor can block cough in naïve guinea pigs. This study aimed to analyse the effect of the NaV1.7 blocker PF-05089771 on cough in guinea pigs with AR.

METHODS

Dunkin Hartley guinea pigs were sensitised and challenged with ovalbumin (OVA). Cough was induced using citric acid aerosol (0.4 M) before nasal challenge (NCH), and then one hour after the 1st, 3rd, and 6th NCH. The OVA-inhibitor group was pre-treated with inhaled NaV1.7 blocker (PF-05089771, 100 μM) before tussigen inhalation.

RESULTS

Chronic AR increased cough response to citric acid in both males and females. Pre-treatment with NaV1.7 blocker significantly inhibited cough reflex by ≈ 75 % in males and ≈ 80 % in females without affecting respiratory rate.

CONCLUSION

NaV1.7 blocker inhalation effectively inhibits cough in guinea pigs with AR.

Trends and research foci in immunoregulatory mechanisms of allergic rhinitis: a bibliometric analysis (2014-2024)

Background

This study aims to provide a comprehensive bibliometric analysis of research trends, hotspots, and future directions in the immunoregulatory mechanisms of allergic rhinitis (AR) from 2014 to 2024.

Methods

Data were sourced from the Web of Science Core Collection (WoSCC), covering articles and reviews published between April 1, 2014, and March 31, 2024. The search terms included "Allergic Rhinitis," "AR," and related terms along with specific keywords related to immune cells and inflammatory mediators. Bibliometric tools such as CiteSpace, VOSviewer, and SCImago Graphica were used to analyze institutional cooperation networks, keyword co-occurrence, citation bursts, and research topic evolution. Microsoft Excel 2019 was employed to display annual publication trends.

Results

A total of 2200 papers met the inclusion and exclusion criteria. The number of publications showed an upward trend over the past decade, with a significant peak in 2021. China (583 papers) and the United States (454 papers) were the major contributing countries. Imperial College London emerged as the leading institution. Key research frontiers identified include the roles of NF kappa B and air pollution in AR. Keyword burst analysis revealed emerging topics such as respiratory allergy and personalized treatment strategies. Notable limitations include the exclusive use of the WoSCC database and the restriction to English-language publications.

Conclusion

The field of immunoregulatory mechanisms in allergic rhinitis has seen significant growth, with China and the United States leading the research. Future research should focus on developing personalized treatment plans and understanding the comprehensive impact of environmental factors. Continued interdisciplinary collaboration and international cooperation will be essential for advancing therapeutic strategies in AR.

Desloratadine alleviates ALS-like pathology in hSOD1G93A mice via targeting 5HTR2A on activated spinal astrocytes

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with progressive loss of motor neurons in the spinal cord, cerebral cortex and brain stem. ALS is characterized by gradual muscle atrophy and dyskinesia. The limited knowledge on the pathology of ALS has impeded the development of therapeutics for the disease. Previous studies have shown that autophagy and astrocyte-mediated neuroinflammation are involved in the pathogenesis of ALS, while 5HTR2A participates in the early stage of astrocyte activation, and 5HTR2A antagonism may suppress astrocyte activation. In this study, we evaluated the therapeutic effects of desloratadine (DLT), a selective 5HTR2A antagonist, in human SOD1G93A (hSOD1G93A) ALS model mice, and elucidated the underlying mechanisms. HSOD1G93A mice were administered DLT (20 mg·kg-1·d-1, i.g.) from the age of 8 weeks for 10 weeks or until death. ALS onset time and lifespan were determined using rotarod and righting reflex tests, respectively. We found that astrocyte activation accompanying with serotonin receptor 2 A (5HTR2A) upregulation in the spinal cord was tightly associated with ALS-like pathology, which was effectively attenuated by DLT administration. We showed that DLT administration significantly delayed ALS symptom onset time, prolonged lifespan and ameliorated movement disorders, gastrocnemius injury and spinal motor neuronal loss in hSOD1G93A mice. Spinal cord-specific knockdown of 5HTR2A by intrathecal injection of adeno-associated virus9 (AAV9)-si-5Htr2a also ameliorated ALS pathology in hSOD1G93A mice, and occluded the therapeutic effects of DLT administration. Furthermore, we demonstrated that DLT administration promoted autophagy to reduce mutant hSOD1 levels through 5HTR2A/cAMP/AMPK pathway, suppressed oxidative stress through 5HTR2A/cAMP/AMPK/Nrf2-HO-1/NQO-1 pathway, and inhibited astrocyte neuroinflammation through 5HTR2A/cAMP/AMPK/NF-κB/NLRP3 pathway in the spinal cord of hSOD1G93A mice. In summary, 5HTR2A antagonism shows promise as a therapeutic strategy for ALS, highlighting the potential of DLT in the treatment of the disease. DLT as a 5HTR2A antagonist effectively promoted autophagy to reduce mutant hSOD1 level through 5HTR2A/cAMP/AMPK pathway, suppressed oxidative stress through 5HTR2A/cAMP/AMPK/Nrf2-HO-1/NQO-1 pathway, and inhibited astrocytic neuroinflammation through 5HTR2A/cAMP/AMPK/NF-κB/NLRP3 pathway in the spinal cord of hSOD1G93A mice.

Effects of 101BHG-D01, a novel M receptor antagonism, on allergic rhinitis in animal models and its mechanism

Allergic rhinitis (AR) is a nasal mucosal disease with sneezing and nasal itching as the main symptoms. Although AR treatment continues to improve, there remains a lack of effective drugs. There are still controversies regarding whether anticholinergic drugs can effectively and safely relieve the symptoms of AR and reduce inflammation in the nasal mucosa. Here, we synthesized 101BHG-D01, which is a novel anticholinergic drug that mainly targets the M3 receptor and may reduce the adverse effects of other anticholinergic drugs on the heart. We evaluated the effects of 101BHG-D01 on AR and investigated the potential molecular mechanism of anticholinergic therapy for AR. We found that 101BHG-D01 effectively alleviated AR symptoms, reduced the infiltration of inflammatory cells and attenuated the expression of inflammatory factors (IL-4, IL-5, IL-13, etc.) in various AR animal models. In addition, 101BHG-D01 reduced the activation of mast cells and the release of histamine from rat peritoneal mesothelial cells (RPMCs) challenged by IgE. Moreover, 101BHG-D01 reduced the expression of MUC5AC in IL-13-challenged rat nasal epithelial cells (RNECs) and human nasal epithelial cells (HNEpCs). Furthermore, IL-13 stimulation significantly increased JAK1 and STAT6 phosphorylation, which was suppressed by 101BHG-D01. We demonstrated that 101BHG-D01 reduced mucus secretion and inflammatory cell infiltration in the nasal mucosa, which may occur through a reduction in activation of the JAK1-STAT6 signaling pathway, indicating that 101BHG-D01 is a potent and safe anticholinergic therapy for AR.

Recent advances in understanding the effects of T lymphocytes on mucosal barrier function in allergic rhinitis

Allergic rhinitis is a non-infectious chronic inflammatory disease of the nasal mucosa that affects T cells and their cytokines. T cells play significant roles in the development of allergic inflammatory diseases by orchestrating mechanisms underlying innate and adaptive immunity. Although many studies on allergic rhinitis have focused on helper T cells, molecular makeup, and pathogenesis-related transduction pathways, pathological mechanisms have not yet been completely explored. Recent studies have suggested that T cell status may play an important role in the interaction between T cells and the nasal mucosal barrier in allergic rhinitis. This study aimed to explore the interactions between T cells and nasal mucosal barriers in allergic rhinitis and to review the therapeutic modalities of pertinent biological agents involving T cells.

Differential regulation of histamine H1 receptor-mediated ERK phosphorylation by Gq proteins and arrestins

Gq protein-coupled histamine H1 receptors play crucial roles in allergic and inflammatory reactions, in which the phosphorylation of extracellular signal-regulated kinase (ERK) appears to mediate the production of inflammatory cytokines. ERK phosphorylation is regulated by G protein- and arrestin-mediated signal transduction pathways. Here, we aimed to explore how H1 receptor-mediated processes of ERK phosphorylation might be differentially regulated by Gq proteins and arrestins. For this purpose, we evaluated the regulatory mechanism(s) of H1 receptor-mediated ERK phosphorylation in Chinese hamster ovary cells expressing Gq protein- and arrestin-biased mutants of human H1 receptors, S487TR and S487A, in which the Ser487 residue in the C-terminal was truncated and mutated to alanine, respectively. Immunoblotting analysis indicated that histamine-induced ERK phosphorylation was prompt and transient in cells expressing Gq protein-biased S487TR, whereas it was slow and sustained in cells expressing arrestin-biased S487A. Inhibitors of Gq proteins (YM-254890) and protein kinase C (PKC) (GF109203X), and an intracellular Ca2+ chelator (BAPTA-AM) suppressed histamine-induced ERK phosphorylation in cells expressing S487TR, but not those expressing S487A. Conversely, inhibitors of G protein-coupled receptor kinases (GRK2/3) (cmpd101), β-arrestin2 (β-arrestin2 siRNA), clathrin (hypertonic sucrose), Raf (LY3009120), and MEK (U0126) suppressed histamine-induced ERK phosphorylation in cells expressing S487A, but not those expressing S487TR. These results suggest that H1 receptor-mediated ERK phosphorylation might be differentially regulated by the Gq protein/Ca2+/PKC and GRK/arrestin/clathrin/Raf/MEK pathways to potentially determine the early and late phases of histamine-induced allergic and inflammatory responses, respectively.

Role of Chemokines and Inflammatory Cells in Respiratory Allergy

The idea of "one airway, one disease" has been gaining importance in the last decade. In the upper and lower airways, allergic mechanisms interact with each other. In the initial stage of respiratory allergic inflammation, allergens contact the respiratory epithelium, which produces chemokines and inflammatory factors, which cause allergic reactions by binding to the corresponding receptors and chemotactic various inflammatory cells to reach the epithelium and tissues. It also drives inflammatory cells to activate and produce more inflammatory factors, thus producing a cascade amplification effect. Inflammatory cell aggregation and activation are very complex and interact with each other in a lattice structure. By blocking the action of various chemokines, inflammatory cell aggregation is reduced, and ultimately the symptoms of respiratory allergy are alleviated. Chemokines can serve as cues for coordinated recruitment of immune cells into and out of tissues, as well as directing the spatial organization of immune cells within tissues and cellular interactions. Chemokines are critical in directing immune cell migration and thus have an important role in the direction of respiratory allergy: however, chemokines are also involved in the production and recruitment of immune cells that contribute to respiratory allergy. In this article, linking the upper and lower respiratory tracts. We review the role of the chemokine system in the respiratory immune response and discuss how respiratory disease modulates overall chemokines to shape the type and outcome of the immune response to the treatment of respiratory allergic disease so that we can further deepen our knowledge of chemokines in the direction of respiratory allergy. In the future, we can do drug research and development based on this network structure and explore new research directions.

Antiallergic drug desloratadine as a selective antagonist of 5HT2A receptor ameliorates pathology of Alzheimer's disease model mice by improving microglial dysfunction

Alzheimer's disease (AD) is a progressively neurodegenerative disease characterized by cognitive deficits and alteration of personality and behavior. As yet, there is no efficient treatment for AD. 5HT_2A receptor (5HT_2A R) is a subtype of 5HT₂ receptor belonging to the serotonin receptor family, and its antagonists have been clinically used as antipsychotics to relieve psychopathy. Here, we discovered that clinically first-line antiallergic drug desloratadine (DLT) functioned as a selective antagonist of 5HT_2A R and efficiently ameliorated pathology of APP/PS1 mice. The underlying mechanism has been intensively investigated by assay against APP/PS1 mice with selective 5HT_2A R knockdown in the brain treated by adeno-associated virus (AAV)-ePHP-si-5HT_2A R. DLT reduced amyloid plaque deposition by promoting microglial Aβ phagocytosis and degradation, and ameliorated innate immune response by polarizing microglia to an anti-inflammatory phenotype. It stimulated autophagy process and repressed neuroinflammation through 5HT_2A R/cAMP/PKA/CREB/Sirt1 pathway, and activated glucocorticoid receptor (GR) nuclear translocation to upregulate the transcriptions of phagocytic receptors TLR2 and TLR4 in response to microglial phagocytosis stimulation. Together, our work has highly supported that 5HT_2A R antagonism might be a promising therapeutic strategy for AD and highlighted the potential of DLT in the treatment of this disease.

Potential synergistic effects of novel hematopoietic prostaglandin D synthase inhibitor TAS-205 and different types of anti-allergic medicine on nasal obstruction in a Guinea pig model of experimental allergic rhinitis

Nasal obstruction is one of the most bothersome symptoms of allergic rhinitis (AR) affecting sleep-related quality of life in AR patients. Although several treatments were tested to control nasal obstruction, some patients with moderate to severe AR do not respond to current treatments, including the combined administration of different types of anti-allergic medicine. Thus, new options for AR treatment are needed. This study aimed to evaluate the effects of combined treatment with a novel inhibitor of hematopoietic prostaglandin D synthase (HPGDS), TAS-205, and different types of anti-allergic medicine on nasal obstruction in AR. Firstly, we demonstrated that TAS-205 selectively inhibited prostaglandin D₂ (PGD₂) synthesis in an enzymatic assay in a cell-based assay and in vivo models of AR. Moreover, treatment with TAS-205 alone suppressed eosinophil infiltration into the nasal cavity and late phase nasal obstruction. The combined administration of TAS-205 with montelukast, a cysteinyl leukotriene receptor 1 antagonist, showed significant additive inhibitory effects on eosinophil infiltration and late phase nasal obstruction compared to treatment with each agent alone. In contrast, concomitant treatment with TAS-205 and fexofenadine, a histamine H₁ blocker, showed inhibitory effects on late phase and early phase nasal obstruction, although the magnitude of the inhibitory effects upon combined administration was comparable to that of each single treatment. These results suggest that combined treatment with an HPGDS inhibitor and different types of anti-allergic medicine may be a promising strategy to control nasal obstruction in AR patients.

Consensus on the methodology for experimental studies in allergic rhinitis

OBJECTIVES

Allergic rhinitis (AR) is a symptomatic disorder of the nose induced by allergen exposure, which triggers immunoglobulin E (IgE)-mediated inflammation of the nasal membranes. Allergic rhinitis is one of the most common health problems and has a major effect on the quality of life.

METHODS

In this review, we aimed to provide a consensus for experimental studies on allergic rhinitis in terms of allergic rhinitis models. For this purpose, we searched for experimental studies in the PubMed, Proquest Central, and Google electronic databases over a 20-year period from the current time (1996-2016). The literature survey was performed using keywords including "allergic rhinitis", "experimental", "animal", "model", "rat", "rabbit", "guinea pig", and "mice" alone or in various combinations. The search identified a total of 285 papers, which were included in this review.

RESULTS

It is vital to select a suitable animal for an allergic model. Rodents like rats, guinea pigs, and mice can produce allergen-specific antibodies with the use of adjuvants. Rats are cheap and the vast majority of the allergen-specific antibodies are immunoglobulin E (IgE). Still, intraperitoneal sensitization is inescapable and adjuvants are required for sensitization. Rats, mice, rabbits, and guinea pigs can be utilized for this reason.

CONCLUSION

This review presented allergic rhinitis models in rats, mice, guinea pigs, and rabbits. Using these methods, researchers may perform well-designed studies.

Glycyrrhizin attenuates histamine-mediated MUC5AC upregulation, inflammatory cytokine production, and aquaporin 5 downregulation through suppressing the NF-κB pathway in human nasal epithelial cells

Allergic rhinitis (AR) is a chronic respiratory inflammatory disease. Glycyrrhizin is a main bioactive component of the licorice root extract and exhibits anti-inflammatory activity. However, the role of glycyrrhizin in AR has not been studied. The aim of the present study was to investigate the effect of glycyrrhizin on histamine-induced human nasal epithelial cells (HNEpCs). Here, we found that glycyrrhizin (20 or 40 μM) inhibited histamine-induced the mRNA expression and secretion of mucin 5 subtype AC (MUC5AC), interleukin (IL)-6 and IL-8 in HNEpCs. The expression levels of aquaporin 5 (AQP5) and phosphorylated cyclic adenosine monophosphate-responsive element binding protein (p-CREB) were decreased by histamine in HNEpCs and increased in cells treated with glycyrrhizin. The glycyrrhizin treatment inhibited histamine-induced expressions of p-NF-κB p65 and p-IκBα in HNEpCs, indicating that glycyrrhizin inhibited the activation of NF-κB pathway in histamine-induced HNEpCs. In addition, inhibition of the NF-κB pathway exhibited the similar effect with glycyrrhizin on histamine-induced HNEpCs. In summary, the results showed that glycyrrhizin reversed the effect of histamine on MUC5AC expression, inflammatory cytokine production, and AQP5 expression in HNEpCs, and the NF-κB pathway was involved in the effect. Glycyrrhizin might be used for complementary and alternative therapeutics of AR.