Human Rhinovirus-induced Proinflammatory Cytokine and Interferon-β Responses in Nasal Epithelial Cells From Chronic Rhinosinusitis Patients

Pathogenesis, Diagnosis, and Treatment of Infectious Rhinosinusitis

Rhinosinusitis is a common inflammatory disease of the sinonasal mucosa and paranasal sinuses. The pathogenesis of rhinosinusitis involves a variety of factors, including genetics, nasal microbiota status, infection, and environmental influences. Pathogenic microorganisms, including viruses, bacteria, and fungi, have been proven to target the cilia and/or epithelial cells of ciliated airways, which results in the impairment of mucociliary clearance, leading to epithelial cell apoptosis and the loss of epithelial barrier integrity and immune dysregulation, thereby facilitating infection. However, the mechanisms employed by pathogenic microorganisms in rhinosinusitis remain unclear. Therefore, this review describes the types of common pathogenic microorganisms that cause rhinosinusitis, including human rhinovirus, respiratory syncytial virus, Staphylococcus aureus, Pseudomonas aeruginosa, Aspergillus species, etc. The damage of mucosal cilium clearance and epithelial barrier caused by surface proteins or secreted virulence factors are summarized in detail. In addition, the specific inflammatory response, mainly Type 1 immune responses (Th1) and Type 2 immune responses (Th2), induced by the entry of pathogens into the body is discussed. The conventional treatment of infectious sinusitis and emerging treatment methods including nanotechnology are also discussed in order to improve the current understanding of the types of microorganisms that cause rhinosinusitis and to help effectively select surgical and/or therapeutic interventions for precise and personalized treatment.

Viral infections and chronic rhinosinusitis

Viral infections are the most common cause of upper respiratory infections; they frequently infect adults once or twice and children 6 to 8 times annually. In most cases, these infections are self-limiting and resolve. However, many patients with chronic rhinosinusitis (CRS) relay that their initiating event began with an upper respiratory infection that progressed in both symptom severity and duration. Viruses bind to sinonasal epithelia through specific receptors, thereby entering cells and replicating within them. Viral infections stimulate interferon-mediated innate immune responses. Recent studies suggest that viral infections may also induce type 2 immune responses and stimulate the aberrant production of cytokines that can result in loss of barrier function, which is a hallmark in CRS. The main purpose of this review will be to highlight common viruses and their associated binding receptors and highlight pathophysiologic mechanisms associated with alterations in mucociliary clearance, epithelial barrier function, and dysfunctional immune responses that might lead to a further understanding of the pathogenesis of CRS.

The Role of Viruses in the Inception of Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) is a complex inflammatory disorder that affects between 2% and 16% of adults in the United States, with estimated healthcare costs between 4 and 12 million USD. Viruses are a common etiologic factor for URIs, are frequently identified in the sinuses of patients with CRS, and trigger CRS exacerbations. Therefore, investigating the role of viruses provides an opportunity to identify their role in the pathogenesis of CRS. In this review, we identified the viruses frequently isolated in patients with CRS, as well as their associated immunologic responses and contributions to inflammation. Rhinovirus, parainfluenza virus, influenza virus, and respiratory syncytial virus are the viruses commonly found in patients with CRS. This information allows us to target pathways early in the pathogenesis of CRS, thereby playing a significant role in slowing the progression of this chronic disease.

Rhinovirus-induced anti-viral interferon secretion is not deficient and not delayed in sinonasal epithelial cells of patients with chronic rhinosinusitis with nasal polyp

Dysregulated innate and adaptive immune response to rhinoviral infection plays an important role in the exacerbation or progressive course of chronic rhinosinusitis (CRS). However, few studies have evaluated whether rhinovirus-induced production of anti-viral interferon is deficient or delayed in inflammatory epithelial cells of patients with CRS with nasal polyps. The aim of the present study is to investigate the replication rates of rhinovirus 16 (RV 16), RV16-induced antiviral interferon secretion, and the expression levels of pattern recognition receptors after RV 16 infection or TLR3 stimulation with poly (I: C) in normal and inflammatory epithelial cells. Inflammatory epithelial cells were obtained from CRS patients with nasal polyps and normal epithelial cells were derived from ethmoid sinus mucosa during endoscopic reduction of blowout fracture or uncinate process mucosa of patients with septal deviation. Cultured cells were infected with RV 16 or treated with poly (I: C) for 24, 48, and 72 h. Cells and media were harvested at each time point and used to evaluate RV16 replication rates, the secretion of IFN-β, -λ1, -λ2, viperin, Mx, and OAS, and the expression levels of TRL3, RIG-I, MDA5, phospho-NFκB, and phospho-IRF3. RV replication rates reached peak levels 48 h after inoculation in both normal and inflammatory epithelial cells and showed no difference between both groups of epithelial cells at any time point. The release of IFN-β, -λ1, and -λ2 in normal and inflammatory epithelial cells was also strongly induced 48 h after RV16 inoculation but reached peak levels 24 h after poly (I: C) treatment. The expression levels of viperin, Mx, OAS, TLR3, RIG-I, MDA5, phospho-NFκB, and phospho-IRF3 showed similar patterns in both groups of epithelial cells. These results suggest that the production of RV16-induced antiviral interferons is not deficient or delayed in inflammatory epithelial cells from CRS patients with nasal polyps.

Human rhinovirus serotypes induces different immune responses

Background

Different species of human rhinovirus (HRV) can induce varied antiviral and inflammatory responses in human blood macrophages and lower airway epithelium. Although human nasal epithelial cells (HNECs) are a primary infection route of HRV, differences between major and minor groups of HRV in the upper airway epithelium have not been studied in detail. In this study, we investigated viral replications and immune responses of major and minor groups of HRV in the HNECs.

Methods

Viral replication, immune responses of IFN-β, IFN-λ, proinflammatory cytokines, and viral receptors, and mRNA expression of transcription factors of HRV16 (major group) and HRV1B (minor group) in the HNECs were assessed.

Results

Compared with HRV16, HRV1B replicated more actively without excessive cell death and produced higher IFN-β, IFN-λ1/3, CXCL10, IL-6, IL-8, and IL-18 levels. Furthermore, low-density lipoprotein receptor (LDLR), TLR3, MDA5, NF-κB, STAT1, and STAT2 mRNA levels increased in HRV1B-infected HNECs.

Conclusion

HRV1B induces a stronger antiviral and inflammatory response from cell entry to downstream signaling compared with HRV16.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12985-021-01701-1.

International consensus statement on allergy and rhinology: rhinosinusitis 2021

I.

EXECUTIVE SUMMARY

BACKGROUND: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR-RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR-RS-2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence-based findings of the document.

METHODS

ICAR-RS presents over 180 topics in the forms of evidence-based reviews with recommendations (EBRRs), evidence-based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary.

RESULTS

ICAR-RS-2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence-based management algorithm is provided.

CONCLUSION

This ICAR-RS-2021 executive summary provides a compilation of the evidence-based recommendations for medical and surgical treatment of the most common forms of RS.

Novel findings in immunopathophysiology of chronic rhinosinusitis and their role in a model of precision medicine

Our understanding of the pathophysiology of chronic rhinosinusitis (CRS) is continuously evolving. The traditional description of CRS in terms of two phenotypes based on the presence or absence of nasal polyps belies the underlying intricate immunopathophysiological processes responsible for this condition. CRS is being increasingly recognized as a disease spectrum encompassing a range of inflammatory states in the sinonasal cavity, with non-type 2 inflammatory disease on one end, type 2 inflammatory, eosinophil-heavy disease on the other and an overlap of both in different proportions in between. Abundance in research on the immune mechanisms of CRS has revealed various new endotypes that hold promise as biomarkers for the development of targeted therapies in severe, uncontrolled CRS. The introduction of precision medicine to manage this chronic, complex condition is a step forward in providing individualized care for all patients with CRS. In this review, the latest research on the pathophysiology of CRS with a focus on potential novel biomarkers and treatment options over the last 2 years are summarized and integrated into a suggested model of precision medicine in CRS.

Chronic rhinosinusitis: pathogenesis, therapy options, and more

INTRODUCTION

When rhinosinusitis - the inflammation of the nasal cavity and paranasal sinuses - persists for over 12 weeks, it is termed 'chronic rhinosinusitis' (CRS). Both innate and adaptive immunity contribute to the heterogeneous inflammatory pathogenesis of CRS, which is driven by genetic and environmental factors and the microbiome. CRS is classified by the presence of polyps. Molecular mechanisms in CRS with nasal polyps are similar to those in atopic diseases.

AREAS COVERED

This review focuses on the immune pathogenesis of CRS, differences between the two CRS subtypes, and latest treatments that may aid in the provision of personalized medicine.

EXPERT OPINION

Basic research in the last decade has helped significantly in enhancing our knowledge of the pathophysiologic processes of CRS, due to which there is now a better understanding of the associated natural history, physiopathology, novel treatments, and prevention strategies. Treatment success depends on the clarification of the underlying pathogenesis and disease-contributing factors. The exploration of disease endotypes and introduction of novel agents are important advancements. Prior studies performed without disease-endotyping resulted in the inefficiency of certain drugs and insignificant results. The identification of biomarkers, development of personalized approaches, and utilization of disease algorithms are required for CRS therapy success.

Enhanced Interferon-β Response Contributes to Eosinophilic Chronic Rhinosinusitis

Type I interferon (IFN-I, including IFN-α and IFN-β) response has been implicated in eosinophilic inflammation, in addition to antiviral function. This study aimed to investigate the role of IFN-I in the pathogenesis of eosinophilic chronic rhinosinusitis (ECRS). IFN-α, IFN-β, cytokine expression, and IFN-β cellular localization in the sinonasal tissue from control subjects and ECRS patients with nasal polyps (NP) were determined using real time-PCR, ELISA, and immunohistochemistry. ECRS was induced in wild-type (WT) and IFNAR1 knockout (Ifnar1^−/−) mice by intranasal challenge with Aspergillus protease and ovalbumin. Stromal cells cultured from NP tissue were stimulated by exogenous IFN-β, and their CCL11 production and IRF3, IRF7, STAT1, STAT2, and IRF9 gene and/or protein expression were measured. IFN-β, IL-5, IL-13, and CCL11 expression was higher in the NP tissue from ECRS patients, compared to the control group. IFN-β was highly colocalized with the CD11c+ cells in NP. IFN-β levels positively correlated with IL-5, IL-13, and CCL11 levels as well as the number of eosinophils in the NP tissue and CT score. The histological severity of ECRS, levels of IL-4, IL-5, IL-13, and CCL11 in the nasal lavage fluid, and total serum IgE levels were less in Ifnar1^−/− mice than in WT mice. CCL11 production, and STAT1 and STAT2 mRNA and STAT1, phospho-STAT1, and phospho-STAT2 protein expression were significantly increased by exogenous IFN-β in NP stromal cells. Our data suggest that IFN-β response was upregulated in ECRS and may play role in ECRS development. IFN-β may contribute to ECRS by enhancing CCL11 production. Thus, increased IFN-β response in the sinonasal mucosa may underlie ECRS pathogenesis.

Innate Immunity of the Lung: From Basic Mechanisms to Translational Medicine

The respiratory tract is faced daily with 10,000 L of inhaled air. While the majority of air contains harmless environmental components, the pulmonary immune system also has to cope with harmful microbial or sterile threats and react rapidly to protect the host at this intimate barrier zone. The airways are endowed with a broad armamentarium of cellular and humoral host defense mechanisms, most of which belong to the innate arm of the immune system. The complex interplay between resident and infiltrating immune cells and secreted innate immune proteins shapes the outcome of host-pathogen, host-allergen, and host-particle interactions within the mucosal airway compartment. Here, we summarize and discuss recent findings on pulmonary innate immunity and highlight key pathways relevant for biomarker and therapeutic targeting strategies for acute and chronic diseases of the respiratory tract.

Viral Infections and Associated Factors That Promote Acute Exacerbations of Asthma

Despite asthma being the most common chronic childhood ailment, there is still much to learn about the disease. Early childhood infections with well-known or emerging viruses can lay the pathophysiologic framework for asthma development and exacerbation later in life, which may be due partly to alteration of the airway microbiome. Once asthma is established, acute exacerbations are usually associated with infections with respiratory viruses, such as rhinoviruses (RVs). Once again, there are bidirectional interactions between viruses and airway bacteria that appear to influence the severity of illness and the likelihood of exacerbation. Studies employing recent advances in viral and bacterial identification analytic techniques will clarify these new concepts and may provide the basis for new treatments or prevention or respiratory infection-associated exacerbation. This paper is a review of the associations among respiratory viruses, bacteria, inflammatory mechanisms, and asthma exacerbation.

Rhinovirus infection in murine chronic allergic rhinosinusitis model

BACKGROUND

Patients with chronic rhinosinusitis (CRS) commonly experience aggravation of their symptoms after viral upper respiratory infection (URI). Rhinovirus (RV) is the most common URI-causing virus. However, there is a lack of a mouse model of RV infection and in vivo studies investigating the effect of RV infection on CRS.

METHODS

A mouse model of chronic allergic rhinosinusitis (CARS) was established by sensitizing to ovalbumin (OVA) through intraperitoneal injection followed by nasal challenges with OVA for 5 weeks. Both control and CARS mice were euthanized at 48 hours after infection with minor group RV serotype 1B (RV1B). Sinonasal complex samples were evaluated histologically; and interleukin (IL)-6, macrophage inflammatory protein (MIP)-2, IL-13, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ were measured in the nasal lavage fluid. The RV1B-infected areas in control and CARS mice were identified using immunofluorescence.

RESULTS

In the infected control mice group, RV1B increased secretory hyperplasia in the sinonasal mucosa and the production of proinflammatory cytokines including INF-γ, MIP-2, and IL-13. Immunohistochemical analysis of nasal mucosa from RV1B-infected mice presented abundant RV1B staining, which was distributed between the epithelium and the lamina propria. In the CARS group, the RV1B-infected area per unit was significantly higher than that in control mice. However, RV1B infection neither increased the proinflammatory cytokine secretion nor worsened the histology significantly.

CONCLUSION

We successfully established a mouse model of upper airway RV infection by nasal inoculation with RV1B. Although there was histologically-proven increased RV infection in the CARS model, the infection did not intensify sinonasal inflammation.

Response to Nonallergenic Irritants in Children With Allergic and Nonallergic Rhinitis

Purpose

Nonallergenic irritants can aggravate the symptoms of rhinitis. We investigated the clinical responses of children with allergic rhinitis (AR) and nonallergic rhinitis (NAR) to nonallergenic irritants, and identified factors associated with these responses.

Methods

Children with chronic rhinitis (n=208) were classified as having AR or NAR based on the presence of aeroallergen-specific IgE. Healthy controls (n=24) were recruited for comparison. The Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines were used to classify patients, and their irritant score (0-21 points) and current symptom score (5-35 points) were measured. Subjects with irritant scores ≥3 and <3 were classified as having irritant and nonirritant rhinitis, respectively.

Results

The mean age of enrolled subjects was 6.8 years (range: 1.8-16.0 years). The AR and NAR groups had similar irritant scores (P=0.394) and proportions of subjects with irritant scores ≥3 (P=0.105). Irritant score correlated positively with symptom score (P=0.005), and the proportion of subjects with irritant scores ≥3 was greater in children with moderate-severe rhinitis than in those with mild rhinitis (P=0.046). Multiple logistic regression analysis indicated that the presence of atopic eczema increased the risk for sensitivity to a nonallergenic irritant (aOR=2.928, 95% CI 1.567-5.473, P=0.001).

Conclusions

Response to a nonallergenic irritant was useful for gauging the severity of rhinitis, but not for differentiating AR from NAR. AR and NAR patients with atopic eczema may increase nasal sensitivity to nonallergenic irritants.