Muco-ciliary differentiation of nasal epithelial cells is decreased after wound healing in vitro

Oncostatin M Contributes to Airway Epithelial Cell Dysfunction in Chronic Rhinosinusitis with Nasal Polyps

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a typical type-2 inflammation involving several cytokines and is associated with epithelial cell dysfunction. Oncostatin M (OSM) (belonging to the interleukin(IL)-6 family) could be a key driver of epithelial barrier dysfunction. Therefore, we investigated the presence of OSM and IL-6 and the expression pattern of tight junctions (TJs) in the nasal tissue of CRSwNP patients and controls using reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) and Western blotting. Then, their potential role in the epithelial barrier was evaluated in vitro in 27 different primary cultures of human nasal epithelial cells (HNECs) by measuring TJ expression and transepithelial electric resistance (TEER) with or without OSM or IL-6 (1, 10, and 100 ng/mL). The effect on ciliary beating efficiency was evaluated by high-speed videomicroscopy and on repair mechanisms with a wound healing model with or without OSM. OSM and IL-6 were both overexpressed, and TJ (ZO-1 and occludin) expression was decreased in the nasal polyps compared to the control mucosa. OSM (100 ng/mL) but not IL-6 induced a significant decrease in TJ expression, TEER, and ciliary beating efficiency in HNECs. After 24 h, the wound repair rate was significantly higher in OSM-stimulated HNECs at 100 ng/mL. These results suggest that OSM could become a new target for monoclonal antibodies.

Shorter Cilia Length and Aberrant Ciliated Marker DNAI1 in Allergic Rhinitis

Purpose

This study aimed to investigate whether the impaired ciliary length and aberrant ciliary ultrastructure marker, dynein axonemal intermediate chain 1 (DNAI1), are important pathological characteristics in nasal mucosa from patients with allergic rhinitis (AR).

Patients and Methods

Biopsies were taken from the inferior turbinate (IT) of controls (n = 20) and patients with AR (n = 20). The ciliary length and the DNAI1 location patterns were assessed by using immunofluorescent staining. Three patterns of DNAI1 localization were defined using a semi-quantitative scoring system: normal (N), partial (P) and absence (A). Every individual section was assigned a score between 0 and 2 in each high-power field (5 fields per sample). The score of 0 = pattern N >70%; 1 = patterns N + P >70%; and 2 = pattern A ≥30%. The receiver operating characteristic (ROC) curve was used to evaluate the predicted value of DNAI1 score for AR.

Results

The ciliary length was reduced by 33.3% in patients with AR compared with controls (P < 0.0001). The higher DNAI1 score was found in the AR group, with a median (first and third quartile) of 0.9 (0.4 and 1.08), which was 0.1 (0 and 0.76) in the control group (P = 0.0071). The ROC of DNAI1 was calculated based on the area under the curve of 0.74 (P = 0.0094). The cutoff value of ROC was 0.5833, with a sensitivity and specificity of 70%.

Conclusion

These results suggested that the shorter ciliary length and aberrant localization of DNAI1 are potentially important pathological characteristics of the allergic nasal mucosa. The aberrant localization of DNAI1 may provide a novel candidate target for clinical management of AR.

Cytokine Signature and Involvement in Chronic Rhinosinusitis with Nasal Polyps

Cytokines are well known to play a central role in chronic rhinosinusitis with nasal polyps (CRSwNP), particularly in maintenance of the inflammatory response and the recruitment of eosinophils. The pathophysiological concepts concerning the involvement of inflammatory cytokines in CRSwNP have gradually evolved. Although the Th2 cytokines environment associated with an eosinophilic infiltration has retained a central role in the genesis of polyps, the role of other cytokine subpopulations has also and more recently been detailed, leading to a specific and complex signature in CRSwNP. The purpose of this review is to summarize the current state of knowledge about the cytokine signature in CRSwNP, the role of cytokines in the pathogenesis of this disease and in the intercellular dialog between epithelial cells, fibroblasts and inflammatory cells. Knowledge of this precise cytokine signature in CRSwNP is fundamental in the perspective of potential targeting biotherapies.

Biological effect of PM10 on airway epithelium-focus on obstructive lung diseases

Recently, a continuous increase in environmental pollution has been observed. Despite wide-scale efforts to reduce air pollutant emissions, the problem is still relevant. Exposure to elevated levels of airborne particles increased the incidence of respiratory diseases. PM₁₀ constitute the largest fraction of air pollutants, containing particles with a diameter of less than 10 μm, metals, pollens, mineral dust and remnant material from anthropogenic activity. The natural airway defensive mechanisms against inhaled material, such as mucus layer, ciliary clearance and macrophage phagocytic activity, may be insufficient for proper respiratory function. The epithelium layer can be disrupted by ongoing oxidative stress and inflammatory processes induced by exposure to large amounts of inhaled particles as well as promote the development and exacerbation of obstructive lung diseases. This review draws attention to the current state of knowledge about the physical features of PM₁₀ and its impact on airway epithelial cells, and obstructive pulmonary diseases.

Key role of the epithelium in chronic upper airways diseases

The respiratory epithelium of the upper airways is a first-line defence against inhaled irritants, pathogens and allergens. It ensures a physical barrier provided by apical junctions and mucociliary clearance to avoid excessive activation of the immune system. The epithelium also forms a chemical and immunological barrier, extensively equipped to protect the airways against external aggressions before the adaptive immune system is required. Under normal circumstances, the epithelium is capable of recovering rapidly after damage. This manuscript reviews these main properties of the upper airway epithelium as well as its reported impairments in chronic inflammatory diseases. The knowledge on normal epithelial functions and their dysregulation in upper airway diseases should help to design new epithelial-targeted treatments.

Altered generation of ciliated cells in chronic obstructive pulmonary disease

In COPD, epithelial changes are prominent features in the airways, such as goblet cell hyperplasia and squamous metaplasia. In contrast, it remains unclear whether ciliated cells are reduced and which pathways dysregulate epithelial differentiation. We hypothesized that bronchial epithelial cell lineage specification is dysregulated in COPD because of an aberrant reprogramming through transforming growth factor (TGF)-β1. Surgical lung tissue from 81 COPD and 61 control (smokers and non-smokers) patients was assessed for bronchial epithelial cell phenotyping by immunohistochemistry, both in situ and in vitro in reconstituted air-liquid interface (ALI) cultures. The role of TGF-β1 was studied in vitro. COPD epithelium in large airways, when compared to controls, showed decreased β-tubulin IV + ciliated cells (4.4%, 2.5–8.8% versus 8.5%, 6.3–11.8% of surface staining, median and IQR, p = 0.0009) and increased MUC5AC + goblet cells (34.8%, 24.4–41.9% versus 10.3%, 5.1–17.6%, p < 0.0001). Both features were recapitulated in the ALI-cultured epithelium from COPD patients. Exogenous TGF-β1 reduced mucociliary differentiation while neutralizing TGF-β1 during ALI increased both specialized cell types. The COPD airway epithelium displays altered differentiation for ciliated cells, which recapitulates in vitro, at least in part through TGF-β1.

FcRn-Dependent Transcytosis of Monoclonal Antibody in Human Nasal Epithelial Cells In Vitro: A Prerequisite for a New Delivery Route for Therapy?

Monoclonal antibodies (mAbs) are promising therapies to treat airway chronic inflammatory disease (asthma or nasal polyps). To date, no study has specifically assessed, in vitro, the potential function of neonatal Fc receptor (FcRn) in IgG transcytosis through the human nasal airway epithelium. The objective of this study was to report the in vitro expression and function of FcRn in nasal human epithelium. FcRn expression was studied in an air–liquid interface (ALI) primary culture model of human nasal epithelial cells (HNEC) from polyps. FcRn expression was characterized by quantitative RT-PCR, western blot, and immunolabeling. The ability of HNECs to support mAb transcytosis via FcRn was assessed by transcytosis assay. This study demonstrates the expression of FcRn mRNA and protein in HNEC. We report a high expression of FcRn in the cytosol of ciliated, mucus, and basal cells by immunohistochemistry with a higher level of FcRn proteins in differentiated HNEC. We also proved in vitro transepithelial delivery of an IgG1 therapeutic mAb with a dose–response curve. This is the first time that FcRn expression and mAb transcytosis has been shown in a model of human nasal respiratory epithelium in vitro. This study is a prerequisite for FcRn-dependent nasal administration of mAbs.

Hyaluronan antagonizes the differentiation effect of TGF-β1 on nasal epithelial cells through down-regulation of TGF-β type I receptor

Although hyaluronan (HA)-based biomaterials have been proposed to promote mucociliary differentiation of nasal epithelial cells (NECs), the mechanism by which HA affects the growth and differentiation of NECs has not been thoroughly explored. This study investigates the effect and mechanism of HA on the differentiation of NECs. The experiment cultures human NECs in four conditions, namely controls, transforming growth factor (TGF)-β1, TGF-β1 + HA and HA groups. In the TGF group, the NECs become irregular shape without formation of tight junction and mucociliary differentiation of NECs is inhibited. Epithelial-mesenchymal transition (EMT) of NECs also occurs in the TGF group. However, with addition of HA in TGF groups, NECs reveal the mucociliary phenotypes of epithelial cells with tight junction expression. Incubation of TGF-β1 in an NEC culture leads to an increase in phosphorylated type 1 TGF-β receptors (p-TβRI). This increase is attenuated when NECs are cultured in the presence of HA. Similar expressions are observed in phosphorylated smad2/smad3. Additionally, HA-dependent inhibition of TGF-β1 signalling is inhibited by co-incubation with a blocking antibody to CD44. Experimental results indicate that HA can antagonize TGF-β1 effect on EMT and mucociliary differentiation of NECs by down-regulation of TβR I, which is via CD44.

Downregulation and Aberrant Localization of Forkhead Box J1 in Allergic Nasal Mucosa

BACKGROUND

Forkhead box J1 (FOXJ1) plays pivotal roles in motile cilia formation. However, it remains unclear whether abnormal expression or localization of FOXJ1 in nasal mucosa tissues is associated with allergic rhinitis (AR), in which impaired mucociliary clearance is implicated.

OBJECTIVE

We sought to investigate the expression and localization of FOXJ1 in inferior turbinate from patients with AR and controls.

METHODS

We assayed mRNA levels of FOXJ1, DNAI1, DNALI1, and DNAH9 by using whole-genome expression array and quantitative real-time polymerase chain reaction. We elucidated the localization of FOXJ1 by using immunofluorescence assays in paraffin sections and primary single cells. Four patterns of FOXJ1 localization (normal, N; intermediate, I; mislocalization, M; absence, A) were defined. We developed a semiquantitative scoring system to elucidate their localization in 5 areas per paraffin section, with individual sections being assigned a score between 0 and 2.

RESULTS

The mRNA levels of FOXJ1, DNAI1, DNALI1, and DNAH9 were significantly reduced in patients with AR compared with controls (all p < 0.05). The median (1st and 3rd quartile) of the FOXJ1 score was 0.4 (0.0 and 0.85) in patients with AR, and 0.2 (0.0 and 0.4) in controls (p < 0.05). For primary cytospin samples, the mean percentages of FOXJ1 localization patterns N, I, M, and A were 46.7, 10.0, 30.0, and 26.7% in patients with AR, and 82.5, 5.0, 5.0, and 7.5% in controls, respectively (p < 0.05).

CONCLUSION

Downregulation and aberrant localization of FOXJ1 may be crucial characteristics of the allergic nasal mucosa.

Models for the study of nasal and sinus physiology in health and disease: A review of the literature

Objective

Chronic sinusitis is a very common yet poorly understood medical condition with significant morbidity. Hence, it remains an entity that is difficult to treat with unsatisfactory outcomes of current management options. This necessitates research into the etiology and pathophysiology of the condition to enhance our knowledge and the therapeutic options. Unfortunately, this kind of research is not always feasible on human subjects due to practical and ethical limitations. Therefore, an alternative model that simulates the disease had to be found in order to overcome these limitations. These models could either be in vivo or in vitro. The aim of our review is to summarize the research findings and key discoveries of both in vivo and in vitro models of chronic sinusitis that have enhanced our understanding of the condition today and have paved the way for the future research of tomorrow.

Data Sources: PubMed literature review.

Methods

A review of the literature was conducted to identify the main successful in vivo and in vitro models for chronic sinusitis.

Results

Creating a successful model for chronic sinusitis is no easy task. Over the years, both in vivo animal models and in vitro tissue culture models were proposed, with each model having its accolades and pitfalls, with the ideal model remaining elusive to this day. However, advancing three‐dimensional cell culturing techniques seems to be a promising new way to find a more accurate model.

Conclusion

None of the current models is perfect for a thorough study of chronic sinusitis. However, three‐dimensional cell cultures have the potential to bridge the gap between in vivo and in vitro studies.

Level of Evidence

NA

Chronic inflammatory airway diseases: the central role of the epithelium revisited

The respiratory epithelium plays a critical role for the maintenance of airway integrity and defense against inhaled particles. Physical barrier provided by apical junctions and mucociliary clearance clears inhaled pathogens, allergens or toxics, to prevent continuous stimulation of adaptive immune responses. The "chemical barrier", consisting of several anti-microbial factors such as lysozyme and lactoferrin, constitutes another protective mechanism of the mucosae against external aggressions before adaptive immune response starts. The reconstruction of damaged respiratory epithelium is crucial to restore this barrier. This review examines the role of the airway epithelium through recent advances in health and chronic inflammatory diseases in the lower conducting airways (in asthma and chronic obstructive pulmonary disease). Better understanding of normal and altered epithelial functions continuously provides new insights into the physiopathology of chronic airway diseases and should help to identify new epithelial-targeted therapies.

Chitosan promotes aquaporin formation and inhibits mucociliary differentiation of nasal epithelial cells through increased TGF-β1 production

Although endoscopic sinus surgery is the mainstay surgical treatment for chronic rhinosinusitis, over 15% of patients require a repeat operation wherein postoperative adhesion formation is one of the main causes of failure. Several recently proposed chitosan-based biomaterials promote mucosal healing, reduce postoperative adhesion formation and restore mucociliary function of sinonasal mucosa. However, the effects of chitosan on cellular morphology, re-epithelization, and mucociliary differentiation of nasal epithelial cells (NECs) during the wound healing process have not been thoroughly investigated. The present study investigates the direct effects of chitosan on cellular growth, cellular migration, mucociliary differentiation and aquaporin (AQP) formation of NECs to elucidate the role of chitosan in sinonasal applications. Wound healing assay reveals that proliferation and migration of NECs are inhibited by incubation of chitosan. The NECs become irregular in shape without formation of tight junction and mucociliary differentiation of NECs is inhibited during a culture period with incubation of chitosan. However, AQP3 and AQP5 formation in NECs is significantly higher in chitosan groups than in control groups. Further, expressions of transforming growth factor (TGF)-β1, Smad2, and Smad3 are significantly higher in the chitosan groups compared with controls. The results of the comparison indicate that chitosan inhibits proliferation, migration and mucociliary differentiation of NECs through increasing production of TGF-β1. Copyright © 2016 John Wiley & Sons, Ltd.

Hepatocyte Growth Factor Gene-Modified Mesenchymal Stem Cells Augment Sinonasal Wound Healing

This study was designed to investigate the effects of hepatocyte growth factor (HGF) transgenic mesenchymal stem cells (HGF-MSCs) on wound healing in the sinonasal mucosa and nasal epithelial cells (NECs). We also sought to determine whether HGF-MSCs and MSCs can migrate into the injured mucosa and differentiate into ciliated cells. Human HGF-overexpressing umbilical cord MSCs (hHGF-UCMSCs) were established, and upregulation of hHGF expression was confirmed by real-time PCR (RT-PCR) and enzyme-linked immunosorbant assay (ELISA). To investigate the paracrine effect of human MSCs (hMSCs) on nasal epithelial repair, hMSC- and HGF-MSC-conditioned media (CM) were used in NEC proliferation assays and in an in vitro scratch-wound repair model. The in vivo sinonasal wound-healing model was established, and all enrolled rabbits were randomly assigned to four groups: the GFP-MSC group, the HGF-MSC group, the Ad-HGF group, and the surgery control group. The average decreased diameter was recorded, and the medial wall of the maxillary sinus was removed for histological analysis and scanning electron microscopy. Collagen deposition in the wound tissue was detected via Masson trichrome (M&T) staining. The distribution of MSCs and HGF-MSCs was observed by immunofluorescence. MSCs improved nasal wound healing both in vivo and in vitro. HGF overexpression in MSCs augmented the curative effects. Reduced collagen deposition and transforming growth factor beta1 (TGF-β1) expression were detected in the HGF-MSC group compared with the MSC-, Ad-HGF-, and phosphate-buffered saline-treated groups based on M&T staining and ELISA. The enhanced therapeutic effects of HGF-MSCs were accompanied by decreased level of the fibrogenic cytokine TGF-β1. In addition, both HGF-MSCs and MSCs can migrate to the injured mucosa and epithelial layer.

Nasal epithelial repair and remodeling in physical injury, infection, and inflammatory diseases

PURPOSE OF REVIEW

To summarize the current knowledge of cellular and molecular mechanisms of nasal epithelial repair and remodeling during physical and pathophysiological conditions.

RECENT FINDINGS

Nasal epithelial repair and remodeling is a highly organized and well coordinated process, involving inflammation, proliferation, differentiation, matrix deposition, and remodeling, and is regulated by a wide variety of growth factors and cytokines. From the in-vivo and in-vitro studies conducted in both human and animal models, undifferentiated basal cells (progenitors) are able to migrate from adjacent epithelium, spread over the denuded basement membrane, and proliferate in injured regions (self-renewal) in necessary (homeostasis) or excessive (hyperplasia) degree. Progenitor cells reorient to an apical-basal polarity, and progressively differentiate into ciliated and nonciliated columnar cells and goblet cells, reconstituting a functional respiratory epithelium after several weeks. This recovery process can be observed during various types and severity of injury, and also in common nasal diseases, including acute viral, allergic, and nonallergic rhinitis, as well as chronic rhinosinusitis with and without nasal polyps.

SUMMARY

Although nearly 10 000 articles about nasal epithelium have been published in the last decade, the mechanisms underlying the nasal epithelial repair are still understood at only a superficial descriptive level. In order to advance rhinology to the next level of a comprehensive knowledge of the orchestrated genetic and molecular processes acting during epithelial repair, combined clinical and experimental studies using sophisticated investigational plans to elucidate the functions of both the protein-coding and regulatory portions of the human genome are required.

[Regeneration of airway epithelium]

INTRODUCTION

Epithelial regeneration is a complex process. It can lead to the remodeling of the airway epithelium as in asthma, COPD or cystic fibrosis.

BACKGROUND

The development of in vivo and in vitro models has allowed the analysis of remodeling mechanisms and showed the role of components of extracellular matrix, proteases, cytokines and growth factors. Airway epithelial progenitors and stems cells have been studied in these models. However, their identification remains difficult.

CONCLUSION

Identification and characterization of airway epithelial progenitor/stem-cells, and a better knowledge of the regeneration process may allow the development of new therapeutic strategies for airway epithelial reconstitution.

Sinonasal epithelial wound resealing in an in vitro model: inhibition of wound closure with IL-4 exposure

BACKGROUND

Prolonged healing and persistent inflammation following surgery for rhinosinusitis impacts patient satisfaction and healthcare resources. Cytokines interleukin (IL)-4, IL-5, and IL-13 are important mediators in T-helper 2 (Th2) inflammatory rhinosinusitis. Decreased wound healing has been demonstrated with Th2 cytokine exposure, but this has not been extensively studied in sinonasal epithelium. We hypothesized that in vitro exposure of primary sinonasal epithelial cell cultures to Th2 inflammatory cytokine IL-4 and IL-13 would impair wound resealing and decrease expression of annexin A2 at the wound edge.

METHODS

Following 24-hour exposure to IL-4, IL-5, or IL-13 vs controls, sterile linear mechanical wounds were created in primary sinonasal epithelial cultures (n = 12 wounds per condition). Wounds were followed for 36 hours or until complete closure, and residual wound areas were calculated by image analysis. Group differences in annexin A2 were assessed by immunofluorescence labeling, confocal microscopy, and Western blots.

RESULTS

Significant wound closure differences were identified across cytokine exposure groups (p < 0.001). Mean percentage wound closure at the completion of the 36-hour time course was 98.41% ± 3.43% for control wounds vs 85.02% ± 18.46% for IL-4 exposed wounds. IL-13 did not significantly impair sinonasal epithelial wound resealing in vitro. Annexin A2 protein levels were decreased in IL-4 treated wounds when compared to control wounds (p < 0.01).

CONCLUSION

Th2 cytokine IL-4 decreases sinonasal epithelial wound closure in vitro. Annexin A2 is also diminished with IL-4 exposure. This supports the hypothesis that IL-4 exposure impairs sinonasal epithelial wound healing and may contribute to prolonged healing in Th2 inflammatory rhinosinusitis.

Caco-2 cell line as a model to evaluate mucoprotective proprieties

Physical protection of mucosa surface and reduction of inflammatory processes are currently considered the main strategies in the treatment and prevention of mucosal diseases. However, the majority of models used to verify the activity of new mucoprotective agents are based on limiting instrumental assessment or the sacrifice of experimental animals. In this study, for the first time, some in vitro experimental methods using Caco-2 cell line are proposed as predicting in vivo behaviour and action of mucoprotective agents. To this purpose, hyaluronic acid and natural polysaccharides for their bioadhesive activity, hydrocortisone and natural polyphenols as anti-inflammatory agents have been chosen. The obtained results demonstrated that the techniques (Con A/o-pd assay and Franz cell system) of mucoadhesive evaluation on Caco-2 cells are useful to compare the activity of each experimental sample and to assess the adhesion time to the mucosal cell surface. Moreover, the reduction of intercellular adhesion molecule-1 (ICAM-1) expression in Caco-2 cells can be considered directly correlated to the mucosal anti-inflammatory effect induced by the hydrocortisone and natural polyphenols. In conclusion, the study supported the use of Caco-2 cell as a model to compare and investigate the effect of different active substances on the mucosa and its diseases.

Assessment of biphasic calcium phosphate to repair nasal septum defects in sheep

BACKGROUND

Saddle nose and septal perforations are among the most surgically challenging situations in nasal reconstruction. They require a significant volume of autologous graft and a complex surgical procedure. The aim of this study was to evaluate the biocompatibility of the biphasic calcium phosphate implant in the nasal septum and its ability to replace septal skeleton with unilateral or bilateral exposure.

METHODS

Thirty sheep underwent anterior nasal septum perforation. Only 20 septa were repaired with the implant exposed to nasal content on bilateral (group 2) and unilateral (group 3) sides. After 45 days of spontaneous cicatrization, the surface of new airway mucosa covering implants and the amount of closure were evaluated macroscopically. Light microscopy, histomorphometry, immunohistochemistry, and transmission electron microscopy were performed to assess soft-tissue growth and differentiation. Statistical analysis was performed by means of the Mann-Whitney test.

RESULTS

The mean rate of mucoperichondrial flap recovery of the implant was 66 percent in group 2 and 82 percent in group 3, and was significantly different from that of the control group (p < 10(-4)). The mean amount of closure was 32 and 64 percent, respectively (p < 10(-3)). The thickness of the perichondrium was greater than the control on both sides (p < 10(-4)). Vascularized soft tissues and bone formation invaded pores of implants. No pathologic inflammation was observed in submucosa. Moderately differentiated and well differentiated newly formed epithelium were the most frequent types observed, with good correlation between immunostaining and morphologic features.

CONCLUSION

These data suggest a good biocompatibility of biphasic calcium phosphate and its ability to repair the nasal septum in sheep.