Adult allergic rhinitis sufferers have unique nasal mucosal and peripheral blood immune gene expression profiles: A case-control study

Establishment of nasal and olfactory epithelium organoids for unveiling mechanism of tissue regeneration and pathogenesis of nasal diseases

Organoid is an ideal in vitro model with cellular heterogeneity and genetic stability when passaging. Currently, organoids are exploited as new tools in a variety of preclinical researches and applications for disease modeling, drug screening, host-microbial interactions, and regenerative therapy. Advances have been made in the establishment of nasal and olfactory epithelium organoids that are used to investigate the pathogenesis of smell-related diseases and cellular/molecular mechanism underlying the regeneration of olfactory epithelium. A set of critical genes are identified to function in cell proliferation and neuronal differentiation in olfactory epithelium organoids. Besides, nasal epithelium organoids derived from chronic rhinosinusitis patients have been established to reveal the pathogenesis of this disease, potentially applied in drug responses in individual patient. The present article reviews recent research progresses of nasal and olfactory epithelium organoids in fundamental and preclinical researches, and proposes current advances and potential future direction in the field of organoid research and application.

LRRC8A drives NADPH oxidase-mediated mitochondrial dysfunction and inflammation in allergic rhinitis

OBJECTIVES

Allergic rhinitis (AR) is a complex disorder with variable pathogenesis. Increasing evidence suggests that the LRRC8A is involved in maintaining cellular stability, regulating immune cell activation and function, and playing significant roles in inflammation. However, the involvement of LRRC8A in AR inflammation and its underlying mechanisms remain unclear.

METHODS

LRRC8A expression in AR patients, confirmed by qRT-PCR and Western blotting, was analyzed to investigate its relationship with the clinical characteristics of AR patients. In vitro, IL-13 stimulated HNEpCs to establish a Th2 inflammation model, with subsequent LRRC8A knockout or overexpression. NOX1/NOX4 inhibitor (GKT137831) and chloride channel inhibitor (DCPIB) were utilized to investigate AR development mechanisms during LRRC8A overexpression. An OVA-induced AR model with nasal mucosa LRRC8A knockdown confirmed LRRC8A's regulatory role in AR inflammation.

RESULTS

LRRC8A mRNA and protein levels were significantly elevated in AR patients, positively correlating with NADPH oxidase subunits and Th2 inflammatory markers. In vitro, IL-13 stimulation of HNEpCs resulted in upregulation of LRRC8A and increased expression of NOX1, NOX4, and p22phox, along with mitochondrial dysfunction and NF-κB pathway activation. The knockout of LRRC8A reversed these effects. In nasal mucosal epithelial cells, DCPIB and GKT137831 completely blocked mitochondrial dysfunction caused by the overexpression of LRRC8A, which led to up-regulation of NOX1, NOX4, and p22phox. In vivo, knocking down LRRC8A reduced eosinophil infiltration, downregulated the expression of NOX1, NOX4, p22phox IL-4, IL-5, and IL-13, and decreased NF-κB pathway activation.

CONCLUSION

LRRC8A drives the upregulation of NOX1, NOX4, and p22phox, leading to ROS overproduction and mitochondrial dysfunction. It also activates NF-κB, ultimately leading to nasal mucosal epithelial inflammation. LRRC8A may be a potential target for the treatment of AR.

Exploring the latest understanding on the role of immune mediators, genetic and environmental factors in pathogenesis of allergic rhinitis: a systematic review

Introduction

Despite well-defined clinical phenotypes of chronic rhinitis, the underlying in-depth pathophysiological mechanism, particularly with reference to the involvement of immune mediators, genetic, and environmental factors, are still not fully understood. Therefore, our aim was to give updated information on the pathogenesis of allergic rhinitis (AR), with an emphasis on the role of cytokines in adults aged 18 years and above. Additionally, we investigated the impact of genetic and environmental factors in the pathogenesis of AR.

Results

A search in various databases identified 1,178 records, and 18 studies were ultimately selected from January 2018 to April 2023. The total sample size in our studies was 4,317, with 2,186 in the experimental and 2,131 in control groups, respectively. The mean age was 33.4 years, with 43% were male, while 57% were female. According to the selected studies, various factors, including immune mediators, particularly cytokines, genetic, and environmental factors, were identified in the development of AR.

Conclusion

The selected studies presented findings on different factors and sub-factors in the pathogenesis of AR, making it a challenge for us to compare their results. However, based on our findings, researchers can link our identified factors to potential therapies for AR.

Caesalpinia sappan Linn. Ameliorates Allergic Nasal Inflammation by Upregulating the Keap1/Nrf2/HO-1 Pathway in an Allergic Rhinitis Mouse Model and Nasal Epithelial Cells

Allergic rhinitis (AR) is a common upper-airway inflammatory disease of the nasal mucosa caused by immunoglobulin (IgE)-mediated inflammation. AR causes various painful clinical symptoms of the nasal mucosa that worsen the quality of daily life, necessitating the urgent development of therapeutic agents. Herein, we investigated the effects of Caesalpinia sappan Linn. heartwood water extract (CSLW), which has anti-inflammatory and antioxidant properties, on AR-related inflammatory responses. We examined the anti-inflammatory and anti-allergic effects of CSLW in ovalbumin (OVA)-induced AR mice and in primary human nasal epithelial cells (HNEpCs). Administration of CSLW mitigated allergic nasal symptoms in AR mice, decreased total immune cell and eosinophil counts in nasal lavage fluid, and significantly reduced serum levels of OVA-specific IgE, histamine, and Th2 inflammation-related cytokines. CSLW also inhibited the infiltration of several inflammatory and goblet cells, thereby ameliorating OVA-induced thickening of the nasal mucosa tissue. We found that CSLW treatment significantly reduced infiltration of eosinophils and production of periostin, MUC5AC, and intracellular reactive oxygen species through the Keap1/Nrf2/HO-1 pathway in HNEpCs. Thus, our findings strongly indicate that CSLW is a potent therapeutic agent for AR and can improve the daily life of patients by controlling the allergic inflammatory reaction of the nasal epithelium.

Allergic Rhinitis: Pathophysiology and Treatment Focusing on Mast Cells

Allergic rhinitis (AR) is a common rhinopathy that affects up to 30% of the adult population. It is defined as an inflammation of the nasal mucosa, develops in allergic individuals, and is detected mostly by a positive skin-prick test. AR is characterized by a triad of nasal congestion, rhinorrhea, and sneezing. Mast cells (MCs) are innate immune system effector cells that play a pivotal role in innate immunity and modulating adaptive immunity, rendering them as key cells of allergic inflammation and thus of allergic diseases. MCs are typically located in body surfaces exposed to the external environment such as the nasal mucosa. Due to their location in the nasal mucosa, they are in the first line of defense against inhaled substances such as allergens. IgE-dependent activation of MCs in the nasal mucosa following exposure to allergens in a sensitized individual is a cardinal mechanism in the pathophysiology of AR. This review is a comprehensive summary of MCs' involvement in the development of AR symptoms and how classical AR medications, as well as emerging AR therapies, modulate MCs and MC-derived mediators involved in the development of AR.

IL-13-programmed airway tuft cells produce PGE2, which promotes CFTR-dependent mucociliary function

Chronic type 2 (T2) inflammatory diseases of the respiratory tract are characterized by mucus overproduction and disordered mucociliary function, which are largely attributed to the effects of IL-13 on common epithelial cell types (mucus secretory and ciliated cells). The role of rare cells in airway T2 inflammation is less clear, though tuft cells have been shown to be critical in the initiation of T2 immunity in the intestine. Using bulk and single-cell RNA sequencing of airway epithelium and mouse modeling, we found that IL-13 expanded and programmed airway tuft cells toward eicosanoid metabolism and that tuft cell deficiency led to a reduction in airway prostaglandin E2 (PGE2) concentration. Allergic airway epithelia bore a signature of PGE2 activation, and PGE2 activation led to cystic fibrosis transmembrane receptor-dependent ion and fluid secretion and accelerated mucociliary transport. These data reveal a role for tuft cells in regulating epithelial mucociliary function in the allergic airway.