Mucin gene expression in rhinitis syndromes

Achievements and Challenges in Transplantation of Mesenchymal Stem Cells in Otorhinolaryngology

Otorhinolaryngology enrolls head and neck surgery in various tissues such as ear, nose, and throat (ENT) that govern different activities such as hearing, breathing, smelling, production of vocal sounds, the balance, deglutition, facial animation, air filtration and humidification, and articulation during speech, while absence of these functions can lead to high morbidity and even mortality. Conventional therapies for head and neck damaged tissues include grafts, transplants, and artificial materials, but grafts have limited availability and cause morbidity in the donor site. To improve these limitations, regenerative medicine, as a novel and rapidly growing field, has opened a new therapeutic window in otorhinolaryngology by using cell transplantation to target the healing and replacement of injured tissues. There is a high risk of rejection and tumor formation for transplantation of embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs); mesenchymal stem cells (MSCs) lack these drawbacks. They have easy expansion and antiapoptotic properties with a wide range of healing and aesthetic functions that make them a novel candidate in otorhinolaryngology for craniofacial defects and diseases and hold immense promise for bone tissue healing; even the tissue sources and types of MSCs, the method of cell introduction and their preparation quality can influence the final outcome in the injured tissue. In this review, we demonstrated the anti-inflammatory and immunomodulatory properties of MSCs, from different sources, to be safely used for cell-based therapies in otorhinolaryngology, while their achievements and challenges have been described too.

Epithelial barriers in allergy and asthma

The respiratory epithelium provides a physical, functional, and immunologic barrier to protect the host from the potential harming effects of inhaled environmental particles and to guarantee maintenance of a healthy state of the host. When compromised, activation of immune/inflammatory responses against exogenous allergens, microbial substances, and pollutants might occur, rendering individuals prone to develop chronic inflammation as seen in allergic rhinitis, chronic rhinosinusitis, and asthma. The airway epithelium in asthma and upper airway diseases is dysfunctional due to disturbed tight junction formation. By putting the epithelial barrier to the forefront of the pathophysiology of airway inflammation, different approaches to diagnose and target epithelial barrier defects are currently being developed. Using single-cell transcriptomics, novel epithelial cell types are being unraveled that might play a role in chronicity of respiratory diseases. We here review and discuss the current understandings of epithelial barrier defects in type 2-driven chronic inflammation of the upper and lower airways, the estimated contribution of these novel identified epithelial cells to disease, and the current clinical challenges in relation to diagnosis and treatment of allergic rhinitis, chronic rhinosinusitis, and asthma.

Th2 cytokines orchestrate the secretion of MUC5AC and MUC5B in IL-5-positive chronic rhinosinusitis with nasal polyps

BACKGROUND

Mucin over-secretion is a significant characteristic of chronic rhinosinusitis with nasal polyps (CRSwNP). This study aimed to investigate the relationship between Th2 cytokines and MUC5AC or MUC5B, and the mechanism of mucin over-secretion in the type-2 inflammatory endotype of CRSwNP.

METHODS

Main Th-cell cytokines, associated mediators, and mucins were determined in the homogenates of nasal polyp samples from 21 CRSwNP patients and inferior turbinate samples from 8 controls, by ELISA or UniCAP system. Secretion of MUC5AC and MUC5B was measured in the supernatants of IL-5, IL-4, or IL-13 primed nasal polyp fragments. Co-localization of MUC5AC, MUC5B, and IL-4 receptor α (IL-4Rα) in CRSwNP and controls was evaluated by immunohistochemistry. Gene expression of IL-4Rα in the samples was measured by real-time reverse transcription-polymerase chain reaction.

RESULTS

Baseline protein levels of the Th2-cytokines IL-4, IL-5, and IL-13, and mucins MUC5AC and MUC5B were significantly higher in the IL-5(+) CRSwNP group, compared to control and IL-5(-) CRSwNP groups. MUC5AC and MUC5B secretions were significantly increased in IL-4- or IL-13-primed, but not IL-5-primed fragments of nasal polyps. Immuno-stained serial sections demonstrated that IL-4Rα was widely expressed in the epithelium and submucosal glands in control and nasal polyp tissues. Gene expression of IL-4Rα was elevated in nasal polyp tissues, specifically in the IL-5(+) CRSwNP group.

CONCLUSIONS

In type-2 inflammatory nasal polyps, characterized by the tissue expression of IL-5, MUC5AC and MUC5B are overexpressed. Both IL-4 and IL-13 may upregulate mucin expression via IL-4Rα, which is also overexpressed in IL-5(+) CRSwNP.

Chronic Rhinosinusitis without Nasal Polyps

Chronic rhinosinusitis without nasal polyps (CRSsNP) is more prevalent than chronic rhinosinusitis with nasal polyps (CRSwNP). Certain diseases predispose to whereas others are associated with CRSsNP. Predisposing diseases include allergic and nonallergic upper and lower airway diseases, epithelial cell disorders, immunodeficiencies, autoimmune diseases, and some infectious diseases. In addition, environmental and host factors, examples of which include smoking, a higher incidence of abnormal biofilms, and innate immune defects, play a role in the pathogenesis of this disease. CRSsNP is characterized by histologic abnormalities, including basement membrane thickening (fibrosis) and goblet cell hyperplasia. Neutrophils and several chemokines, TGF-β and C-X-C motif chemokine ligand (CXCL)-8, play a role in CRSsNP remodeling. However, there are conflicting data about CRSsNP endotypes, for example, whether it is characterized by neutrophilia or eosinophilia or both. In spite of advancements and the understanding of the pathogenesis of this disease, additional study is necessary to better comprehend its underlying mechanisms, endotypes, and evidence-based treatment strategies.

Upper airway stem cells: understanding the nose and role for future cell therapy

The nose together with the paranasal sinuses has an approximate surface area of 100 to 200 cm(2) in adults, which is lined with pseudostratified columnar ciliated epithelium. It serves several important physiological functions such as conditioning and filtration of the inspired air and the provision of end organ for the sense of smell. It is also a physical and immunological barrier as it is the first site of interaction between the host tissue and foreign invaders (viruses, bacteria, and allergens). Our understanding of the complex cellular events occurring in response to inhaled agents during the development of common airway diseases has been significantly enhanced by the current status of in vivo and in vitro nasal experimental models. This will allow the development of novel therapeutic strategies designed to improve the physiological and immune defense functions of the nasal epithelium, as well as novel therapies for other common nasal diseases.

Expression of pendrin and periostin in allergic rhinitis and chronic rhinosinusitis

BACKGROUND

Pendrin and periostin are newly identified mediators of the inflammatory process. The expression of these proteins in human sinonasal tissue and their roles in allergic rhinitis and chronic rhinosinusitis remain to be elucidated. This study investigated the expression of pendrin and periostin in sinonasal tissue of patients with allergic rhinitis, chronic rhinosinusitis, and aspirin-induced asthma. Prospective control study conducted at Yamagata University, Japan.

METHODS

Surgical samples were investigated by means of real-time reverse transcription-polymerase chain reaction to evaluate the expression of pendrin and periostin mRNA. The presence and location of pendrin and periostin were determined by immunohistochemistry and Western blotting.

RESULTS

Pendrin and periostin production was significantly higher in patients with nasal disorders than in controls. Further significant increases in periostin expression were noted in patients with chronic rhinosinusitis with nasal polyps and in those with aspirin-induced asthma. Immunohistochemistry revealed positive staining for pendrin in epithelial cells and submucosal glands and for periostin in the basement membrane in all three disorders, and additionally for periostin in nasal polyp tissue in chronic rhinosinusitis and aspirin-induced asthma.

CONCLUSIONS

Production of pendrin and periostin is upregulated in allergic rhinitis, chronic rhinosinusitis with nasal polyps, and aspirin-induced asthma. These findings suggest that pendrin can induce mucus production and that periostin can induce tissue fibrosis and remodeling in the nasal mucosa. Therefore, these mediators may be therapeutic target candidates for allergic rhinitis, chronic rhinosinusitis with nasal polyps, and aspirin-induced asthma.

Histologic characteristics and mucin immunohistochemistry of cystic fibrosis sinus mucosa

OBJECTIVES

To evaluate the histologic characteristics of paranasal sinus mucosa of a disease control population and children with chronic rhinosinusitis and cystic fibrosis (CRS/CF) (1) to determine whether goblet cell (GC) hyperplasia and/or submucosal gland (SMG) hyperplasia occur in pediatric CRS/CF and (2) to compare expression and localization of MUC5AC and MUC5B mucins in the sinus mucosa of both cohorts.

DESIGN

Histologic and morphometric analyses of paranasal sinus mucosa were used to quantify the number of GCs and mucin-expressing cells. Digital imaging was used to evaluate the SMG area. Immunohistochemistry was performed to identify the cellular localization of MUC5AC and MUC5B mucins, and confocal microscopy was used to determine whether MUC5AC and MUC5B mucins were expressed in the same secretory cells.

SETTING

Children's National Medical Center, Washington, DC.

PARTICIPANTS

Twenty-one children with CRS/CF who underwent endoscopic sinus surgical procedures and 18 children who underwent craniofacial resection or neurosurgical procedures for abnormalities other than sinusitis.

RESULTS

A statistically significant increased area (4.4-fold) of SMGs was detected in the sinus mucosa of patients with CRS/CF compared with the controls (P = .02). Neither GC hyperplasia nor increased expression of MUC5AC was observed in the CRS/CF group. MUC5AC was expressed only in a subpopulation of GCs in both cohorts, and MUC5B was expressed in a subpopulation of GCs as well as in SMGs. There was a positive trend toward increased glandular MUC5B expression in the CRS/CF cohort. Colocalization of MUC5AC and MUC5B expression was observed in a subset of GCs.

CONCLUSIONS

Significant SMG hyperplasia and a trend toward increased glandular MUC5B expression exist in children with CRS/CF. This suggests that SMG hyperplasia and glandular MUC5B mucin contribute to mucus overproduction in the sinus mucosa of this population.

Local drug delivery

Topical drug delivery for sinonasal disorders is influenced by a variety of factors. Macroscopically (or anatomically), the ability of the drug to reach the appropriate region of the paranasal system is paramount. Delivery techniques, surgical state of the sinus cavity, delivery device, and fluid dynamics (volume, pressure, position) have a significant impact on the delivery of topical therapies to the sinus mucosa. Once topical therapeutics actually reach the desired site, factors within the local microenvironment heavily influence local drug delivery. The presence and composition of the mucus blanket, mucociliary clearance, direct mucin-drug binding, and the permeability of pharmaceutical compounds will all impact drug delivery. In addition, the general therapeutic goal of topical management may lie between the potentially competing actions of mechanical lavage and pharmaceutical intervention. Techniques for the mechanical removal of mucus, antigen, and inflammatory products may not be the most efficient approach for pharmaceutical delivery. This article reviews the evolving concepts in local drug therapy, both for the factors that influence anatomic distribution within the sinonasal system and those that affect mucosal absorption.

Corticosteroid therapy increases membrane-tethered while decreases secreted mucin expression in nasal polyps

BACKGROUND

Mucus hypersecretion is a hallmark of nasal polyposis (NP). Corticosteroids (CS) are first-line treatment for NP, decreasing their size and inflammatory component. However, their effect on mucin production is not well-understood. The aim of this (pilot) study was to investigate CS effect on mucin expression in NP.

METHODS

Patients were randomized in control (n = 9) and treatment (oral prednisone for 2 weeks and intranasal budesonide for 12 weeks; n = 23) groups. Nasal polyposis from nonasthmatic (NP; n = 13), aspirin-tolerant (NP-ATA; n = 11) and aspirin-intolerant (NP-AIA; n = 8) asthmatics were studied. Nasal polyposis biopsies were obtained before (w0) and after 2 (w2) and 12 (w12) weeks of CS treatment. Secreted (MUC5AC, MUC5B and MUC8) and membrane-tethered (MUC1, MUC4) mucins (immunohistochemistry) and goblet cells (Alcian blue-periodic acid Schiff) were quantified in both epithelium and glands. Rhinorrea and nasal obstruction were also assessed.

RESULTS

At w2, steroids increased MUC1 (from 70 to 97.5) and MUC4 (from 80 to 100) in NP-ATA patients' epithelium compared with baseline (w0). At w12, steroids decreased MUC5AC (from 40 to 5) and MUC5B (from 45 to 2.5) in NP-ATA patients' epithelium and glands, respectively, compared with baseline. No mucin presented significant changes in NP-AIA patients. MUC5AC and MUC5B expression correlated with goblet and mucous cell numbers, respectively, and MUC5AC also with rhinorrea score.

CONCLUSIONS

These results suggest: (i) CS up-regulate membrane (MUC1, MUC4) while down-regulate secreted (MUC5AC, MUC5B) mucins; (ii) there exists a link between secreted mucin expression and goblet cell hyperplasia; and (iii) NP from AIA may develop resistance to CS treatment.