IL-4 drastically decreases deuterosomal and multiciliated cells via alteration in progenitor cell differentiation

Differential regulation of viral entry-associated genes modulated by inflammatory cytokines in the nasal epithelium

This study aimed to investigate the impact of different types of nasal inflammation on the regulation of entry-associated genes of respiratory viruses, including severe acute respiratory syndrome coronavirus 2 (SARS CoV-2), Middle East respiratory syndrome coronavirus (MERS-CoV), human coronavirus 229E (HCoV-229E), and influenza virus, in the nasal epithelium. Subjects were classified into three groups: control, eosinophilic chronic rhinosinusitis (ECRS), and noneosinophilic CRS (NECRS) groups. Angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine subtype 2 (TMPRSS2), alanyl aminopeptidase (ANPEP), dipeptidyl peptidase 4 (DPP4), and beta-galactoside alpha-2,6-sialyltransferase 1 (ST6GAL1), and beta-galactoside alpha-2,3-sialyltransferase 4 (ST3GAL4) were selected as key entry-associated genes for SARS-CoV-2, HCoV-229E, MERS-CoV, and influenza, respectively, and were evaluated. Brushing samples obtained from each group and human nasal epithelial cells cultured using an air-liquid interface system were treated for 7 days with typical inflammatory cytokines and analyzed using real-time polymerase chain reaction. Western blot analysis and confocal microscopy were performed. The entry-associated genes showed distinct regulation patterns in response to each interleukin-4 (IL-4), interleukin-13 (IL-13), tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ). Specifically, ACE2 significantly decreased in type 2 cytokines (IL-4 and IL-13), while TMPRSS2 significantly decreased in type 1 cytokines (TNF-α and IFN-γ). ANPEP significantly decreased in both types of cytokines. Remarkably, DPP4 significantly increased in type 2 cytokines and decreased in type 1 cytokines. Moreover, ST6GAL1 and ST3GAL4 significantly increased in type 2 cytokines and decreased in type 1 cytokines, particularly IFN-γ. These findings were supported by western blot analysis and confocal imaging results, especially for ACE2 and DPP4. The findings regarding differential regulation suggest that patients with ECRS, primarily mediated by type 2 inflammation, may have lower susceptibility to SARS-CoV-2 and HCoV-229E infections but higher susceptibility to MERS-CoV and influenza infections.

Transcriptional analysis of primary ciliary dyskinesia airway cells reveals a dedicated cilia glutathione pathway

Primary ciliary dyskinesia (PCD) is a genetic condition that results in dysmotile cilia. The repercussions of cilia dysmotility and gene variants on the multiciliated cell remain poorly understood. We used single-cell RNA-Seq, proteomics, and advanced microscopy to compare primary culture epithelial cells from patients with PCD, their heterozygous mothers, and healthy individuals, and we induced pluripotent stem cells (iPScs) generated from a patient with PCD. Transcriptomic analysis revealed unique signatures in PCD airway cells compared with their mothers' cells and the cells of healthy individuals. Gene expression in heterozygous mothers' cells diverged from both control and PCD cells, marked by increased inflammatory and cellular stress signatures. Primary and iPS-derived PCD multiciliated cells had increased expression of glutathione-S-transferases GSTA2 and GSTA1, as well as NRF2 target genes, accompanied by elevated levels of reactive oxygen species (ROS). Immunogold labeling in human cilia and proteomic analysis of the ciliated organism Chlamydomonas reinhardtii demonstrated that GSTA2 localizes to motile cilia. Loss of human GSTA2 and C. reinhardtii GSTA resulted in slowed cilia motility, pointing to local cilia regulatory roles. Our findings identify cellular responses unique to PCD variants and independent of environmental stress and uncover a dedicated ciliary GSTA2 pathway essential for normal motility that may be a therapeutic target.

Intranasal delivery of low-dose anti-CD124 antibody enhances treatment of chronic rhinosinusitis with nasal polyps

Frequent injections of anti-CD124 monoclonal antibody (αCD124) over long periods of time are used to treat chronic rhinosinusitis with nasal polyps (CRSwNP). Needle-free, intranasal administration (i.n.) of αCD124 is expected to provide advantages of localized delivery, improved efficacy, and enhanced medication adherence. However, delivery barriers such as the mucus and epithelium in the nasal tissue impede penetration of αCD124. Herein, two novel protamine nanoconstructs: allyl glycidyl ether conjugated protamine (Nano-P) and polyamidoamine-linked protamine (Dendri-P) were synthesized and showed enhanced αCD124 penetration through multiple epithelial layers compared to protamine in mice. αCD124 was mixed with Nano-P or Dendri-P and then intranasally delivered for the treatment of severe CRSwNP in mice. Micro-CT and pathological changes in nasal turbinates showed that these two nano-formulations achieved ∼50 % and ∼40 % reductions in nasal polypoid lesions and eosinophil count, respectively. Both nano-formulations provided enhanced efficacy in suppressing nasal and systemic Immunoglobulin E (IgE) and nasal type 2 inflammatory biomarkers, such as interleukin 13 (IL-13) and IL-25. These effects were superior to those in the protamine formulation group and subcutaneous (s.c.) αCD124 given at a 12.5-fold higher dose. Intranasal delivery of protamine, Nano-P, or Dendri-P did not induce any measurable toxicities in mice.

Nicotiana benthamiana-derived dupilumab-scFv reaches deep into the cultured human nasal epithelial cells and inhibits CCL26 expression

Plants offer a cost-effective and scalable pharmaceutical platform devoid of host-derived contamination risks. However, their medical application is complicated by the potential for acute allergic reactions to external proteins. Developing plant-based protein therapeutics for localized diseases with non-invasive treatment modalities may capitalize on the benefits of plant proteins while avoiding their inherent risks. Dupilumab, which is effective against a variety of allergic and autoimmune diseases but has systemic responses and injection-related side effects, may be more beneficial if delivered locally using a small biological form. In this study, we engineered a single-chain variable fragment (scFv) of dupilumab, termed Dup-scFv produced by Nicotiana benthamiana, and evaluated its tissue permeability and anti-inflammatory efficacy in air-liquid interface cultured human nasal epithelial cells (HNECs). Despite showing 3.67- and 17-fold lower binding affinity for IL-4Ra in surface plasmon resonance assays and cell binding assays, respectively, Dup-scFv retained most of the affinity of dupilumab, which was originally high, with a dissociation constant (KD) of 4.76 pM. In HNECs cultured at the air-liquid interface, Dup-scFv administered on the air side inhibited the inflammatory marker CCL26 in hard-to-reach basal cells more effectively than dupilumab. In addition, Dup-scFv had an overall permeability of 0.8% across cell layers compared to undetectable levels of dupilumab. These findings suggest that plant-produced Dup-scFv can be delivered non-invasively to cultured HNESc to alleviate inflammatory signaling, providing a practical approach to utilize plant-based proteins for topical therapeutic applications.

Updated epithelial barrier dysfunction in chronic rhinosinusitis: Targeting pathophysiology and treatment response of tight junctions

Tight junction (TJ) proteins establish a physical barrier between epithelial cells, playing a crucial role in maintaining tissue homeostasis by safeguarding host tissues against pathogens, allergens, antigens, irritants, etc. Recently, an increasing number of studies have demonstrated that abnormal expression of TJs plays an essential role in the development and progression of inflammatory airway diseases, including chronic obstructive pulmonary disease, asthma, allergic rhinitis, and chronic rhinosinusitis (CRS) with or without nasal polyps. Among them, CRS with nasal polyps is a prevalent chronic inflammatory disease that affects the nasal cavity and paranasal sinuses, leading to a poor prognosis and significantly impacting patients' quality of life. Its pathogenesis primarily involves dysfunction of the nasal epithelial barrier, impaired mucociliary clearance, disordered immune response, and excessive tissue remodeling. Numerous studies have elucidated the pivotal role of TJs in both the pathogenesis and response to traditional therapies in CRS. We therefore to review and discuss potential factors contributing to impair and repair of TJs in the nasal epithelium based on their structure, function, and formation process.

Airway epithelial CD47 plays a critical role in inducing influenza virus-mediated bacterial super-infection

Respiratory viral infection increases host susceptibility to secondary bacterial infections, yet the precise dynamics within airway epithelia remain elusive. Here, we elucidate the pivotal role of CD47 in the airway epithelium during bacterial super-infection. We demonstrated that upon influenza virus infection, CD47 expression was upregulated and localized on the apical surface of ciliated cells within primary human nasal or bronchial epithelial cells. This induced CD47 exposure provided attachment sites for Staphylococcus aureus, thereby compromising the epithelial barrier integrity. Through bacterial adhesion assays and in vitro pull-down assays, we identified fibronectin-binding proteins (FnBP) of S. aureus as a key component that binds to CD47. Furthermore, we found that ciliated cell-specific CD47 deficiency or neutralizing antibody-mediated CD47 inactivation enhanced in vivo survival rates. These findings suggest that interfering with the interaction between airway epithelial CD47 and pathogenic bacterial FnBP holds promise for alleviating the adverse effects of super-infection.

The origins and longevity of IgE responses as indicated by serological and cellular studies in mice and humans

The existence of long-lived IgE antibody-secreting cells (ASC) is contentious, with the maintenance of sensitization by the continuous differentiation of short-lived IgE+ ASC a possibility. Here, we review the epidemiological profile of IgE production, and give an overview of recent discoveries made on the mechanisms regulating IgE production from mouse models. Together, these data suggest that for most individuals, in most IgE-associated diseases, IgE+ ASC are largely short-lived cells. A subpopulation of IgE+ ASC in humans is likely to survive for tens of months, although due to autonomous IgE B cell receptor (BCR) signaling and antigen-driven IgE+ ASC apoptosis, in general IgE+ ASC probably do not persist for the decades that other ASC are inferred to do. We also report on recently identified memory B cell transcriptional subtypes that are the likely source of IgE in ongoing responses, highlighting the probable importance of IL-4Rα in their regulation. We suggest the field should look at dupilumab and other drugs that prohibit IgE+ ASC production as being effective treatments for IgE-mediated aspects of disease in most individuals.

Novel small molecule-mediated restoration of the surface expression and anion exchange activity of mutated pendrin causing Pendred syndrome and DFNB4

Variants in SLC26A4 (pendrin) are the most common reasons for genetic hearing loss and vestibular dysfunction in East Asians. In patients with Pendred syndrome and DFNB4 (autosomal recessive type of genetic hearing loss 4), caused by variants in SLC26A4, the hearing function is residual at birth and deteriorates over several years, with no curative treatment for these disorders. In the present study, we revealed that a novel small molecule restores the expression and function of mutant pendrin. High-throughput screening of 54,000 small molecules was performed. We observed that pendrin corrector (PC2-1) increased the surface expression and anion exchange activity of p.H723R pendrin (H723R-PDS), the most prevalent genetic variant that causes Pendred syndrome and DFNB4. Furthermore, in endogenous H723R-PDS-expressing human nasal epithelial cells, PC2-1 significantly increased the surface expression of pendrin. PC2-1 exhibited high membrane permeability in vitro and high micromolar concentrations in the cochlear perilymph in vivo. In addition, neither inhibition of Kv11.1 activity in the human ether-a-go-go-related gene assay nor cell toxicity in the cell proliferation assay was observed at a high PC2-1 concentration (30 μM). These preclinical data support the hypothesis of the druggability of mutant pendrin using the novel corrector molecule PC2-1. In conclusion, PC2-1 may be a new therapeutic molecule for ameliorating hearing loss and treating vestibular disorders in patients with Pendred syndrome or DFNB4.

Unraveling the Role of Epithelial Cells in the Development of Chronic Rhinosinusitis

The pathophysiology of CRS is multifactorial and complex yet needs to be completed. Recent evidence emphasizes the crucial part played by epithelial cells in the development of CRS. The epithelial cells act as physical barriers and play crucial roles in host defense, including initiating and shaping innate and adaptive immune responses. This review aims to present a comprehensive understanding of the significance of nasal epithelial cells in CRS. New research suggests that epithelial dysfunction plays a role in developing CRS through multiple mechanisms. This refers to issues with a weakened barrier function, disrupted mucociliary clearance, and irregular immune responses. When the epithelial barrier is compromised, it can lead to the passage of pathogens and allergens, triggering inflammation in the body. Furthermore, impaired mucociliary clearance can accumulate pathogens and secretions of inflammatory mediators, promoting chronic inflammation. Epithelial cells can release cytokines and chemokines, which attract and activate immune cells. This can result in an imbalanced immune response that continues to cause inflammation. The interaction between nasal epithelial cells and various immune cells leads to the production of cytokines and chemokines, which can either increase or decrease inflammation. By comprehending the role of epithelial cells in CRS, we can enhance our understanding of the disease's pathogenesis and explore new therapeutics.