Aberrant epithelial remodeling with impairment of cilia architecture in non-cystic fibrosis bronchiectasis

A case-control study on the risk factors associated with the occurrence of non-tuberculous mycobacteria pulmonary disease in bronchiectasis patients

OBJECTIVE

The objective of this study is to analyze the risk factors associated with bronchiectasis combined with non-tuberculous mycobacteria pulmonary disease(NTM-PD) and provide a basis for more effective prevention and treatment strategies.

METHODS

The study subjects for this manuscript were patients with bronchiectasis who were admitted to the infection department between January 2021 and June 2023.There were 34 patients with NTM-PD in the observation group, and 52 patients with simple bronchiectasis in the control group. Basic information, imaging features, serum albumin levels, and infection indicators were collected from both groups of patients.Univariate and multivariate logistic regression analysis were performed to analyze the risk factors for NTM-PD in patients with bronchiectasis.

RESULTS

Multivariate logistic regression analysis revealed that bronchiectasis exacerbation occurring at least twice a year(OR = 3.884, 95% CI: 1.200-12.568), involvement of three or more lung lobes with bronchiectasis (OR = 3.932, 95% CI: 1.208-12.800), hypoalbuminemia (OR = 3.221, 95% CI: 1.015-10.219), and the NLR index (OR = 1.595, 95% CI: 1.200-2.119) were significant risk factors for non-tuberculous mycobacteria pulmonary disease in individuals with bronchiectasis (P < 0.05).

CONCLUSION

Patients with bronchiectasis accompanied by NTM-PD present specific risk factors that should be promptly addressed through prevention and treatment.

Down-expression of Foxj1 on airway epithelium with impaired cilia architecture in non-cystic fibrosis bronchiectasis implies disease severity

INTRODUCTION

The pathogenesis of non-cystic fibrosis bronchiectasis has not been clearly clarified. This study aimed to investigate the expression of ciliary regulating protein forkhead box protein j1 (Foxj1) on airway epithelium in non-cystic fibrosis bronchiectasis and its association with airway cilia structure disorder and disease severity.

METHODS

Lung tissue sections excised from 47 patients with non-cystic fibrosis bronchiectasis were included between January 2018 and June 2021. Specimens from 26 subjects who underwent a lobectomy due to lung nodule were chosen as controls. Clinical information was collected, and pathologic analysis was performed to assess the epithelial structure and expression of ciliary regulating Foxj1.

RESULTS

Of the 47 patients with non-cystic fibrosis bronchiectasis, 25 were considered as mild, 12 were moderate whereas the remaining 10 cases were severe according to the bronchiectasis severity index score evaluation. Epithelial hyperplasia, hyperplasia of goblet cells and inflammatory cell infiltration were observed in non-cystic fibrosis bronchiectasis, compared with control subjects. Cilia length in non-cystic fibrosis bronchiectasis patients were shorter than that in the control group, (5.34 ± 0.89) μm versus (7.34 ± 0.71) μm, respectively (P = 0.002). The expression of Foxj1 was (2.69 ± 1.09) × 10⁶ in non-cystic fibrosis bronchiectasis, compared with (6.67 ± 1.15) × 10⁶ in the control group (P = 0.001). Moreover, patients with lower expression of Foxj1 showed shorter airway cilia and worse in disease severity.

CONCLUSION

Foxj1 declined in the airway epithelium of patients with non-cystic fibrosis bronchiectasis, positively correlated to cilia length and might imply worse disease severity.

Multiomics Analysis of a DNAH5-Mutated PCD Organoid Model Revealed the Key Role of the TGF-β/BMP and Notch Pathways in Epithelial Differentiation and the Immune Response in DNAH5-Mutated Patients

Dynein axonemal heavy chain 5 (DNAH5) is the most mutated gene in primary ciliary dyskinesia (PCD), leading to abnormal cilia ultrastructure and function. Few studies have revealed the genetic characteristics and pathogenetic mechanisms of PCD caused by DNAH5 mutation. Here, we established a child PCD airway organoid directly from the bronchoscopic biopsy of a patient with the DNAH5 mutation. The motile cilia in the organoid were observed and could be stably maintained for an extended time. We further found abnormal ciliary function and a decreased immune response caused by the DNAH5 mutation through single-cell RNA sequencing (scRNA-Seq) and proteomic analyses. Additionally, the directed induction of the ciliated cells, regulated by TGF-β/BMP and the Notch pathway, also increased the expression of inflammatory cytokines. Taken together, these results demonstrated that the combination of multiomics analysis and organoid modelling could reveal the close connection between the immune response and the DNAH5 gene.

Motile Ciliary Disorders of the Nasal Epithelium in Adults With Bronchiectasis

BACKGROUND

Motile ciliary disorder (MCD) has been implicated in chronic inflammatory airway diseases such as asthma and COPD.

RESEARCH QUESTION

What are the characteristics of MCD of the nasal epithelium and its association with disease severity and inflammatory endotypes in adults with bronchiectasis?

STUDY DESIGNS AND METHODS

In this observational study, we recruited 167 patients with bronchiectasis and 39 healthy control participants who underwent brushing of the nasal epithelium. A subgroup of patients underwent bronchoscopy for bronchial epithelium sampling (n = 13), elective surgery for bronchial epithelium biopsy (n = 18), and blood sampling for next-generation sequencing (n = 37). We characterized systemic and airway inflammatory endotypes in bronchiectasis. We conducted immunofluorescence assays to profile ultrastructural (dynein axonemal heavy chain 5 [DNAH5], dynein intermediate chain 1 [DNAI1], radial spoke head protein 9 [RSPH9]) and ciliogenesis marker expression (ezrin).

RESULTS

MCD was present in 89.8% of patients with bronchiectasis, 67.6% showed secondary MCD, and 16.2% showed primary plus secondary MCD. Compared with healthy control participants, patients with bronchiectasis yielded abnormal staining patterns of DNAH5, DNAI1, and RSPH9 (but not ezrin) that were more prominent in moderate to severe bronchiectasis. MCD pattern scores largely were consistent between upper and lower airways and between large-to-medium and small airways in bronchiectasis. Coexisting nasal diseases and asthma did not confound nasal ciliary ultrastructural marker expression significantly. The propensity of MCD was unaffected by the airway or systemic inflammatory endotypes. MCD, particularly an ultrastructural abnormality, was notable in patients with mild bronchiectasis who showed blood or sputum eosinophilia.

INTERPRETATION

Nasal ciliary markers profiling provides complimentary information to clinical endotyping of bronchiectasis.

Rheology predicts sputum eosinophilia in patients with muco-obstructive lung diseases

BACKGROUND

Mucus is known to play a pathogenic role in muco-obstructive lung diseases, but little is known about the determinants of mucus rheology. The purpose of this study is to determine which sputum components influence sputum rheology in patients with muco-obstructive lung diseases.

METHODS

We performed a cross sectional prospective cohort study. Spontaneous sputum was collected from consecutive patients with muco-obstructive lung diseases. Sputum rheology was assessed using the Rheomuco® rheometer (Rheonova, Grenoble); the elastic modulus G', viscous modulus G″, and the critical stress threshold σc were recorded. Key quantitative and qualitative biological sputum components were determined by cytology, nucleic acid amplification tests and mass spectrometry.

RESULTS

48 patients were included from January to August 2019. Among them, 10 had asthma, 14 COPD and 24 non-CF bronchiectasis (NCFB). The critical stress threshold σc predicted a sputum eosinophilia superior to 1.25% with 89.19% accuracy (AUC = 0.8762). G' and G″ are positively correlated with MUC5AC protein concentration ((rho = 0.361; P = .013) and (rho = 0.335; P = .021), respectively). σc was positively correlated with sputum eosinophilia (rho = 0.394; P = .012), MUC5B (rho = 0.552; P < .001) and total protein (rho = 0.490; P < .001) concentrations. G' and G″ were significantly higher in asthma patients (G' = 14.49[7.18-25.26]Pa, G'' = 3.0[2.16-5.38]Pa) compared to COPD (G' = 5.01[2.94-6.48]Pa, P = .010; G'' = 1.45[1.16-1.94]Pa, P = .006) and to NCFB (G' = 4.99[1.49-10.49]Pa, P = .003; G'' = 1.46[0.71-2.47]Pa, P = .002).

CONCLUSION

In muco-obstructive lung diseases, rheology predicts sputum eosinophilia and is correlated with mucin concentrations, regardless of the underlying disease.

CLINICAL TRIAL REGISTRATION

(registrar, website, and registration number), where applicable NCT04081740.

The Novel Regulatory Role of the lncRNA–miRNA–mRNA Axis in Chronic Inflammatory Airway Diseases

Chronic inflammatory airway diseases, characterized by airway inflammation and airway remodelling, are increasing as a cause of morbidity and mortality for all age groups and races across the world. The underlying molecular mechanisms involved in chronic inflammatory airway diseases have not been fully explored. MicroRNAs (miRNAs) and long noncoding RNAs (lncRNAs) have recently attracted much attention for their roles in the regulation of a variety of biological processes. A number of studies have confirmed that both lncRNAs and miRNAs can regulate the initiation and progression of chronic airway diseases by targeting mRNAs and regulating different cellular processes, such as proliferation, apoptosis, inflammation, migration, and epithelial–mesenchymal transition (EMT). Recently, accumulative evidence has shown that the novel regulatory mechanism underlying the interaction among lncRNAs, miRNAs and messenger RNAs (mRNAs) plays a critical role in the pathophysiological processes of chronic inflammatory airway diseases. In this review, we comprehensively summarized the regulatory roles of the lncRNA–miRNA–mRNA network in different cell types and their potential roles as biomarkers, indicators of comorbidities or therapeutic targets for chronic inflammatory airway diseases, particularly chronic obstructive pulmonary disease (COPD) and asthma.

Research advances and clinical management of bronchiectasis: Chinese perspective

Bronchiectasis is a debilitating chronic suppurative airway disease that confers a substantial burden globally. Despite the notable prevalence, research on bronchiectasis in mainland China remains in its infancy. Nevertheless, there has been a significant leap in the quantity and quality of research, which has contributed to the ever-improving clinical practice. A nationwide collaborative platform has been established to foster multicentre studies, which will help increase the level of evidence further. Here, we summarise the status quo of clinical management and consider the research priorities for bronchiectasis that have been published previously. We also highlight the efforts of the Chinese medical communities to outline the core tasks that need to be addressed within the next decade.

Rationale and Clinical Use of Bronchodilators in Adults with Bronchiectasis

Currently, there is much controversy surrounding the therapeutic approach to pulmonary function abnormalities in patients with bronchiectasis and, consequently, whether and when to use bronchodilators in these patients. National and international guidelines on the treatment of bronchiectasis in adults do not recommend the routine use of bronchodilators because there is no evidence that a significant response to a bronchodilator or the presence or hyperresponsiveness of the airway are good predictors of future effective clinical response. However, some guidelines recommend them in the presence of airway obstruction and/or special conditions, which vary according to the guideline in question, although there are no recommendations on optimal dosing and bronchodilator treatment combined with or without inhaled corticosteroids. Nonetheless, in contrast with guideline recommendations, bronchodilators are overused in real-world patients with bronchiectasis even in the absence of airway obstruction, as demonstrated by analysis of national and international registries. This overuse can be explained by the awareness of the existence of a solid pharmacological rationale that supports the use of bronchodilators in the presence of chronic airway obstruction independent of its aetiology. We performed a systematic review of the literature and were able to verify that there are no randomised controlled trials (apart from a small study with methodological limitations and a very recent trial involving a not-very-large number of patients), or any long-term observational studies on the short- or long-term effect of bronchodilators in patients with bronchiectasis. Therefore, we believe that it is essential and even urgent to evaluate the effects of bronchodilators in these patients with appropriately designed studies.

Host Antiviral Response Suppresses Ciliogenesis and Motile Ciliary Functions in the Nasal Epithelium

Background

Respiratory viral infections are one of the main drivers of development and exacerbation for chronic airway inflammatory diseases. Increased viral susceptibility and impaired mucociliary clearance are often associated with chronic airway inflammatory diseases and served as risk factors of exacerbations. However, the links between viral susceptibility, viral clearance, and impaired mucociliary functions are unclear. Therefore, the objective of this study is to provide the insights into the effects of improper clearance of respiratory viruses from the epithelium following infection, and their resulting persistent activation of antiviral response, on mucociliary functions.

Methods

In order to investigate the effects of persistent antiviral responses triggered by viral components from improper clearance on cilia formation and function, we established an in vitro air–liquid interface (ALI) culture of human nasal epithelial cells (hNECs) and used Poly(I:C) as a surrogate of viral components to simulate their effects toward re-epithelization and mucociliary functions of the nasal epithelium following damages from a viral infection.

Results

Through previous and current viral infection expression data, we found that respiratory viral infection of hNECs downregulated motile cilia gene expression. We then further tested the effects of antiviral response activation on the differentiation of hNECs using Poly(I:C) stimulation on differentiating human nasal epithelial stem/progenitor cells (hNESPCs). Using this model, we observed reduced ciliated cell differentiation compared to goblet cells, reduced protein and mRNA in ciliogenesis-associated markers, and increased mis-assembly and mis-localization of ciliary protein DNAH5 following treatment with 25 μg/ml Poly(I:C) in differentiating hNECs. Additionally, the cilia length and ciliary beat frequency (CBF) were also decreased, which suggest impairment of ciliary function as well.

Conclusion

Our results suggest that the impairments of ciliogenesis and ciliary function in hNECs may be triggered by specific expression of host antiviral response genes during re-epithelization of the nasal epithelium following viral infection. This event may in turn drive the development and exacerbation of chronic airway inflammatory diseases.

Aberrant Epithelial Cell Proliferation in Peripheral Airways in Bronchiectasis

Dilation of bronchi and bronchioles caused by destruction and excessive epithelial remodeling is a characteristic feature of bronchiectasis. It is not known how epithelial progenitor cells contribute to these pathologic conditions in peripheral airways (bronchioles) in bronchiectasis. We aimed to explore the expression levels of signature airway progenitor cells in the dilated bronchioles in patients with bronchiectasis. We obtained the surgically resected peripheral lung tissues from 43 patients with bronchiectasis and 33 control subjects. Immunostaining was performed to determine the expression patterns of thyroid transcription factor-1 (TTF-1, for labeling progenitor cells in distal airways), P63 (basal cells), club cell 10 kDa protein (CC10, club cells), and surfactant protein C (SPC, alveolar type II epithelial cells) in epithelium or sub-epithelium. Here, we reported significantly lower percentage of TTF-1⁺ cells and CC10⁺ cells, and higher percentage of P63⁺ cells within the epithelium of dilated bronchioles compared with control bronchioles. In airway sub-epithelium of the dilated bronchioles, epithelial hyperplasia with disarrangement of TTF-1⁺ cells yielded cuboidal (100%) and columnar (93.0%) type among bronchiectasis patients. Most progenitor cell markers co-localized with TTF-1. The median (the 1st, 3rd quartile) percentage of P63⁺TTF-1⁺, CC10⁺TTF-1⁺, and SPC⁺TTF-1⁺ cells was 16.0% (8.9, 24.0%), 14.5% (7.1, 20.8%), and 52% (40.3, 64.4%), respectively. For cuboidal epithelial hyperplasia, 91.0% (86.5, 94.0%) of areas co-stained with SPC and TTF-1. Columnar epithelial hyperplasia was characterized by TTF-1 co-staining with P63⁺TTF-1⁺ and CC10⁺TTF-1⁺ cells. Taken together, aberrant proliferation of airway progenitor cells in both epithelium and sub-epithelium are implicated in bronchiectasis.

An Integrated Analysis of Radial Spoke Head and Outer Dynein Arm Protein Defects and Ciliogenesis Abnormality in Nasal Polyps

Background: Nasal polyp (NP) is a chronic upper airway inflammatory disease that is frequently triggered by defective host-defense. However, the mechanisms underlying the impaired barrier function such as cilia-mediated mucociliary clearance remain poorly understood.

Objective: To assess ciliary ultrastructural and ciliogenesis marker expression and the phenotypes of ciliated cells in NP.

Methods: NP biopsy samples were obtained from 97 NP patients and inferior turbinate from 32 healthy controls. Immunofluorescence staining, quantitative polymerase chain reaction, and single-cell cytospin staining were performed. We classified the patterns of radial spoke head protein (RSPH) 1, 4A (RSPH4A), 9 (RSPH9), and dynein axonemal heavy chain 5 (DNAH5) localization. A semi-quantitative scoring system was developed to assess their expression patterns and associations with ciliogenesis markers [centrosomal protein 110 (CP110) and forkhead box j1 (FOXJ1)].

Results: Median scores of RSPH1, RSPH4A, RSPH9, and DNAH5 were significantly higher in NP than in healthy controls, particularly in eosinophilic NPs. Expression pattern scores of RSPH1, RSPH4A, RSPH9, and DNAH5 correlated positively with each other in both groups. In primary-cell specimens, abnormal expression patterns were significantly more common in NP. The total fluorescence intensity of CP110 and FOXJ1 was significantly higher in NPs and correlated positively with expression pattern scores of RSPH1, RSPH4A, RSPH9, and DNAH5. A trend towards lengthened cilia was observed in NP.

Conclusion: In the chronic airway inflammatory milieu, the up-regulated ciliogenesis correlates with the abnormal expression of ciliary ultrastructural markers (i.e., DNAH5) in NP (particularly eosinophilic NP).

Motile Ciliary Disorders in Chronic Airway Inflammatory Diseases: Critical Target for Interventions

PURPOSE OF REVIEW

Impaired mucociliary clearance has been implicated in chronic upper and lower airway inflammatory diseases (i.e., allergic and non-allergic rhinitis, chronic rhinosinusitis with or without nasal polyps and asthma). How motile ciliary disorders (impaired ciliogenesis, ciliary beating and ultrastructural defects) are implicated in chronic airway inflammatory diseases is not fully understood. Elaboration of the role of motile ciliary disorders may serve as therapeutic targets for improving mucociliary clearance, thereby complementing contemporary disease management.

RECENT FINDINGS

We have summarized the manifestations of motile ciliary disorders and addressed the underlying associations with chronic airway inflammatory diseases. A panel of established and novel diagnostic tests and therapeutic interventions are outlined. Physicians should be vigilant in screening for motile ciliary disorders, particularly in patients with co-existing upper and lower airway inflammatory diseases. Proper assessment and treatment of motile ciliary disorders may have added value to the management and prevention of chronic airway inflammatory diseases.