HNE Induces the Hyperexpression of MUC5AC in Chronic Rhinosinusitis With Nasal Polyps by Activating the TRAF6/Autophagy Regulatory Axis

Autophagy in chronic rhinosinusitis with or without nasal polyps

Basic research on chronic rhinosinusitis (CRS) has advanced significantly in the past two decades, yet a comprehensive understanding of its pathogenic mechanisms remains elusive. Concurrently, there is a growing interest among scientists in exploring the involvement of autophagy in various human diseases, including tumors and inflammatory conditions. While the role of autophagy in asthma has been extensively studied in airway inflammatory diseases, its significance in CRS with or without nasal polyps (NPs), a condition closely linked to asthma pathophysiology, has also garnered attention, albeit with conflicting findings across studies. This review delves into the role of autophagy in CRS, suggesting that modulating autophagy to regulate inflammatory responses could potentially serve as a novel therapeutic target.

Effects of Pendrin Protein in Nasal Epithelial Cells on Mucin Production in the Context of Type 2 Inflammation

Background: Chronic rhinosinusitis (CRS) is a heterogeneous disease. The pathogenesis of chronic sinusitis is still unclear; however, the nasal cavity and paranasal sinuses are commonly affected by type 2 inflammation, which is caused by Th2 cytokines such as interleukin (IL)-5, IL-4, and IL-13. Previous studies have shown that pendrin promotes local infiltration of neutrophils through the production of human neutrophil elastase (HNE), which is essential for the secretion of mucin 5AC (MUC5AC) in chronic inflammatory diseases of the lower respiratory tract. This study investigated pendrin expression and its relationship to mucin in type 2 inflammation. Methods: A total of 40 patients (10 CRS patients with nasal polyps,10 CRS patients without nasal polyps, and 20 nasal septum deviation patients) were included in this study and were divided into the CRS group and the NC group. A normal nasal mucosa tissue culture model was established in vitro. IL-13 was used to stimulate primary cultures of human nasal epithelial cells (HNECs). Western blot (WB), enzyme-linked immunosorbent assay (ELISA), and quantitative real-time polymerase chain reaction (qRT-PCR) were used to detect the expression of pendrin, MUC5AC, and MUC5B. After transfecting HNECs with siRNA pendrin or negative control (NC), EGF receptor (EGFR), HNE, MUC5AC, and MUC5B expression were analyzed using qRT-PCR, WB, or ELISA in terms of their relationships with pendrin. Pendrin expression in the tissue was also analyzed. Results: After IL-13 stimulation, pendrin, MUC5AC, and MUC5B expression levels were upregulated; the optimal concentration of IL-13 was 50 ng/mL. The expression levels of HNE, EGFR, MUC5AC, and MUC5B were downregulated after transfection with siRNA pendrin-1650. Pendrin expression in the NC group was lower than in the CRS group. Conclusion: IL-13 is implicated in the inflammation of nasal mucosa, and pendrin is closely related to the excessive secretion of mucin. The expression of mucin is downregulated after transfection with siRNA pendrin. There is a positive relationship between pendrin and EFGR/HNE. Moreover, pendrin plays an important role in type 2 inflammation.

Understanding the CRSwNP Patient as Whole

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a distinct inflammatory disease of the upper airways with a significant impact on the health and quality of life of affected patients. Several comorbid conditions such as allergic rhinitis, asthma, sleep disorders, and gastroesophageal reflux disease are commonly reported in patients with CRSwNP.

OBJECTIVE

In this article, we intended to review the UpToDate information on how these comorbidities can impact CRSwNP patients' health and well-being.

METHODS

A PUBMED search was performed to review relevant recent article on the topic.

RESULTS

While there have been significant advances in the knowledge and management options for CRSwNP in the past few years, additional studies are needed to understand the underlying pathophysiologic mechanisms of these associations. In addition, awareness of the impact of CRSwNP on mental health, quality of life, and cognition is paramount to treating this condition.

CONCLUSION

Recognition and addressing CRSwNP comorbidities such as allergic rhinitis, asthma, sleep disorders, gastroesophageal reflux disease, and cognitive function impairment are important to optimally understand and manage the patient with CRSwNP as a whole.

Neutrophilic inflammation in chronic rhinosinusitis

PURPOSE OF REVIEW

Over the last years, extensive research has been done on neutrophils and their contribution in chronic rhinosinusitis (CRS), and made it clear that they are more than just a bystander in this disease. In this article, we will review all recent publications on this topic and look to what the future hold regarding therapeutics targeting the neutrophilic inflammation in CRS.

RECENT FINDINGS

Evidence is growing that the presence of neutrophils are associated with a worse disease outcome in certain CRS patient groups. They are highly activated in type 2 inflammations and exhibit damaging properties through their proteases, contributing to the chronicity of the disease. Several recent studies identified useful biomarkers and targets for future therapeutics.

SUMMARY

The findings we review in this manuscript are of utmost importance in unraveling the complexity of CRS and provide us with the necessary knowledge for future clinical practices.

Pathogenesis and treatment of chronic rhinosinusitis from the perspective of sinonasal epithelial dysfunction

Background

Chronic rhinosinusitis (CRS) is a clinical syndrome primarily characterized by long-term mucosal inflammation of the nasal cavity and sinuses. The pathogenesis of CRS is still unclear due to its high heterogeneity. A number of studies have recently focused on the sinonasal epithelium. Thus, there has been a quantum leap in awareness of the role of the sinonasal epithelium, which is now understood as an active functional organ rather than simply an inert mechanical barrier. Undoubtedly, epithelial dysfunction plays a vital role in the onset and development of CRS.

Objective

In this article, we discuss the potential contribution of sinonasal epithelium dysfunction to CRS pathogenesis and explore a few current and developing therapeutic options targeting the sinonasal epithelium.

Results

Impaired mucociliary clearance (MCC) and an abnormal sinonasal epithelial barrier are usually considered to be the main causative factors in CRS. Epithelial-derived bioactive substances, such as cytokines, exosomes, and complements, play a vital role in the regulation of innate and adaptive immunity and contribute to the pathophysiological alterations of CRS. The phenomena of epithelial-mesenchymal transition (EMT), mucosal remodeling, and autophagy observed in CRS offer some novel insights into the pathogenesis of this disease. In addition, existing treatment options targeting disorder of sinonasal epithelium can help to relieve the main symptoms associated with CRS to some extent.

Conclusion

The presence of a normal epithelium is fundamental for maintaining homeostasis in the nasal and paranasal sinuses. Here, we describe various aspects of the sinonasal epithelium and highlight the contributions of epithelial dysfunction to CRS pathogenesis. Our review provides sound evidence of the need for in-depth study of the pathophysiological alterations of this disease and for the development of novel epithelium-targeting alternative treatments.