IL-25-induced activation of nasal fibroblast and its association with the remodeling of chronic rhinosinusitis with nasal polyposis

Matrix metalloproteinases in chronic rhinosinusitis

INTRODUCTION

Matrix metalloproteinases (MMPs) are a group of enzymes that are essential in maintaining extracellular matrix (ECM) homeostasis, regulating inflammation and tissue remodeling. In chronic rhinosinusitis (CRS), the overexpression of certain MMPs can contribute to chronic nasal tissue inflammation, ECM remodeling, and tissue repair.

AREAS COVERED

This review provides a comprehensive overview of the biological characteristics and functions of the MMP family, particularly focusing on the expression and activity of MMPs in patients with CRS, and delves into their role in the pathogenesis of CRS and their potential as therapeutic targets.

EXPERT OPINION

MMPs are important in tissue remodeling and have been implicated in the pathophysiology of CRS. Previous studies have shown that the expression of MMPs is upregulated in the nasal mucosa of patients with CRS and positively correlates with the severity of CRS. However, there is still a large gap in the research content of MMP in CRS, and the specific expression and pathogenic mechanism of MMP still need to be clarified. The significance and value of the ratio of MMP to tissue inhibitors of metalloproteinase (TIMP) in diseases still need to be demonstrated. Moreover, further studies are needed to assess the efficacy and safety of biologics that target MMPs in patients with CRS.

The current findings in eosinophilic chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a persistent inflammatory disease of the nasal cavity and paranasal sinuses. Traditional classification is denoted by the presence (CRSwNP) or absence of nasal polyps (CRSsNP). Particularly, CRSwNP is distinguished by the presence of infiltrating cells and inflammatory markers in the nasal mucosa. Patients with CRSwNP in Western countries predominantly display a type 2 endotype, whereas those in Asian regions display a mixed type 2 endotype. Nevertheless, recent transcriptome analyses have revealed two types of nasal polyps - type 2 and non-type 2 polyps, suggesting that geographical differences in endotypes likely resulted from the different proportions of each endotype. Moreover, various endotypes of CRSsNP have been identified, making phenotype a crucial factor for predicting treatment efficacy. Type 2 endotypes, designated as eosinophilic CRS (ECRS) in Japan, are characterized by severe eosinophilic infiltration into the paranasal sinus tissue and are particularly refractory. In this review, we discuss the latest developments in ECRS. We also provide recent findings on the involvement of nasal epithelial cells in pathogenesis.

The Inhibition Effect and Mechanism of Staurosporine Isolated from Streptomyces sp. SNC087 Strain on Nasal Polyp

This study aims to explore the potential inhibition effects of staurosporine isolated from a Streptomyces sp. SNC087 strain obtained from seawater on nasal polyps. Staurosporine possesses antimicrobial and antihypertensive activities. This research focuses on investigating the effects of staurosporine on suppressing the growth and development of nasal polyps and elucidating the underlying mechanisms involved. The experimental design includes in vitro and ex vivo evaluations to assess the inhibition activity and therapeutic potential of staurosporine against nasal polyps. Nasal polyp-derived fibroblasts (NPDFs) were stimulated with TGF-β1 in the presence of staurosporine. The levels of α-smooth muscle actin (α-SMA), collagen type-I (Col-1), fibronectin, and phosphorylated (p)-Smad 2 were investigated using Western blotting. VEGF expression levels were analyzed in nasal polyp organ cultures treated with staurosporine. TGF-β1 stimulated the production of Col-1, fibronectin, and α-SMA and was attenuated by staurosporine pretreatment. Furthermore, these inhibitory effects were mediated by modulation of the signaling pathway of Smad 2 in TGF-β1-induced NPDFs. Staurosporine also inhibits the production of VEGF in ex vivo NP tissues. The findings from this study will contribute to a better understanding of staurosporine's role in nasal polyp management and provide insights into its mechanisms of action.

Role of Fibroblasts in Chronic Inflammatory Signalling in Chronic Rhinosinusitis with Nasal Polyps-A Systematic Review

Chronic rhinosinusitis with nasal polyps (CRSwNP) is an inflammatory disease of the nose and paranasal sinuses characterized by the presence of nasal polyps. The symptoms produced by the presence of nasal polyps such as nasal obstruction, nasal discharge, facial pain, headache, and loss of smell cause a worsening in the quality of life of patients. The source of the nasal polyps remains unclear, although it seems to be due to a chronic inflammation process in the sinonasal mucosa. Fibroblasts, the main cells in connective tissue, are intimately involved in the inflammation processes of various diseases; to this end, we carried out a systematic review to evaluate their inflammatory role in nasal polyps. Thus, we evaluated the main cytokines produced by nasal polyp-derived fibroblasts (NPDF) to assess their involvement in the production of nasal polyps and their involvement in different inflammatory pathways. The results of the review highlight the inflammatory role of NPDF through the secretion of various cytokines involved in the T1, T2, and T3 inflammatory pathways, as well as the ability of NPDF to be stimulated by a multitude of substances. With these findings, the fibroblast is positioned as a new potential therapeutic target in the treatment of CRSwNP.

Pathogenesis of Nasal Polyposis: Current Trends

Chronic Rhinosinusitis (CRS) is characterized by edema of the sub-epithelial layers, but, only specific types of CRS are developing polyps. Nasal polyposis may develop under different pathogenetic mechanisms rendering the typical macroscopic classification of CRS, with or without nasal polyps, rather deficient. Currently, we approach nasal polyposis, in terms of diagnosis and treatment, according to its endotype, which means that we focus on the specific cells and cytokines that are participating in its pathogenesis. It appears that the molecular procedures that contribute to polyp formation, initiating with a Th-2 response of the adaptive immune system, are local phenomena occurring in the sub-epithelial layers of the mucosa. Several hypotheses are trying to approach the etiology that drives the immune response towards Th-2 type. Extrinsic factors, like fungi, Staphylococcus superantigens, biofilms, and altered microbiome can contribute to a modified and intense local reaction of the immune system. Some hypotheses based on intrinsic factors like the elimination of Treg lymphocytes, low local vitamin-D levels, high levels of leukotrienes, epithelial to mesenchymal transition (EMT) induced by hypoxia, and altered levels of NO, add pieces to the puzzle of the pathogenesis of nasal polyposis. Currently, the most complete theory is that of epithelial immune barrier dysfunction. Intrinsic and extrinsic conditions can damage the epithelial barrier rendering sub-epithelial layers more vulnerable to invasion by pathogens that trigger a Th-2 response of the adaptive immune system. Th2 cytokines, subsequently, induce the accumulation of eosinophils and IgE together with the remodeling of the stroma in the sub-epithelial layers leading, eventually, to the formation of nasal polyps.

Role of Nasal Fibroblasts in Airway Remodeling of Chronic Rhinosinusitis: The Modulating Functions Reexamined

Chronic rhinosinusitis (CRS) is a multifactorial inflammatory disease of the nose and sinuses that affects more than 10% of the adult population worldwide. Currently, CRS is classified into endotypes according to the inflammatory response (Th1, Th2, and Th17) or the distribution of immune cells in the mucosa (eosinophilic and non-eosinophilic). CRS induces mucosal tissue remodeling. Extracellular matrix (ECM) accumulation, fibrin deposition, edema, immune cell infiltration, and angiogenesis are observed in the stromal region. Conversely, epithelial-to-mesenchymal transition (EMT), goblet cell hyperplasia, and increased epithelial permeability, hyperplasia, and metaplasia are found in the epithelium. Fibroblasts synthesize collagen and ECM, which create a structural skeleton of tissue and play an important role in the wound-healing process. This review discusses recent knowledge regarding the modulation of tissue remodeling by nasal fibroblasts in CRS.

Epidermal growth factor activates a hypoxia-inducible factor 1α-microRNA-21 axis to inhibit aquaporin 4 in chronic rhinosinusitis

The pathogenesis of chronic rhinosinusitis (CRS) is largely unknown, but accumulating evidence supports the role of the airway epithelium in its pathophysiology. In our study here, we evaluated whether epidermal growth factor (EGF) regulates a hypoxia-inducible factor 1α (HIF-1α)-microRNA-21 (miR-21)-aquaporin 4 (AQP4) axis in nasal epithelial cells from CRS patients. We found that, compared with normal sinus mucosa, EGF, HIF-1α, and miR-21 were upregulated and AQP4 was downregulated in sinus mucosa from patients with CRS and in a CRS mouse model. It was established that EGF upregulated HIF-1α and miR-21 expression, that HIF-1α regulated miR-21 transcription, and that the AQP4 gene was a target of miR-21. Knockdown of EGF and HIF-1α mRNAs and of miR-21, or overexpression of AQP4 mRNA, inhibited proliferation and promoted apoptosis of hypoxia-exposed human nasal epithelial cells, effects that were associated with reduced levels of α-SMA, fibronectin, and vimentin, as well as promoted caspase-3 activity and E-cadherin levels. In the mouse CRS model, EGF elevation increased in vivo production of inflammatory IL-4 and IFN-γ to promote CRS, which was reversed by AQP4 elevation. Collectively, EGF upregulates HIF-1α and miR-21 expression to inhibit AQP4 expression, thereby promoting the proliferation of nasal epithelial cells and the development of CRS.

The role of hypoxia in the pathophysiology of chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a chronic inflammatory disease of the nasal cavity characterized by excessive nasal mucus secretion and nasal congestion. The development of CRS is related to pathological mechanisms induced by hypoxia. Under hypoxic conditions, the stable expression of both Hypoxia inducible factor-1 (HIF-1) α and HIF-2α are involved in the immune response and inflammatory pathways of CRS. The imbalance in the composition of nasal microbiota may affect the hypoxic state of CRS and perpetuate existing inflammation. Hypoxia affects the differentiation of nasal epithelial cells such as ciliated cells and goblet cells, induces fibroblast proliferation, and leads to epithelial-mesenchymal transition (EMT) and tissue remodeling. Hypoxia also affects the proliferation and differentiation of macrophages, eosinophils, basophils, and mast cells in sinonasal mucosa, and thus influences the inflammatory state of CRS by regulating T cells and B cells. Given the multifactorial nature in which HIF is linked to CRS, this study aims to elucidate the effect of hypoxia on the pathogenic mechanisms of CRS.

Immunological Aspects of Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) is related to persistent inflammation with a dysfunctional relationship between environmental agents and the host immune system. Disturbances in the functioning of the sinus mucosa lead to common clinical symptoms. The major processes involved in the pathogenesis of CRS include airway epithelial dysfunctions that are influenced by external and host-derived factors which activate multiple immunological mechanisms. The molecular bases for CRS remain unclear, although some factors commonly correspond to the disease: bacterial, fungal and viral infections, comorbidity diseases, genetic dysfunctions, and immunodeficiency. Additionally, air pollution leads increased severity of symptoms. CRS is a heterogeneous group of sinus diseases with different clinical courses and response to treatment. Immunological pathways vary depending on the endotype or genotype of the patient. The recent knowledge expansion into mechanisms underlying the pathogenesis of CRS is leading to a steadily increasing significance of precision medicine in the treatment of CRS. The purpose of this review is to summarize the current state of knowledge regarding the immunological aspects of CRS, which are essential for ensuring more effective treatment strategies.

Aspirin Actions in Treatment of NSAID-Exacerbated Respiratory Disease

Non-steroidal Anti-inflammatory drugs (NSAID)-exacerbated respiratory disease (N-ERD) is characterized by nasal polyposis, chronic rhinosinusitis, adult-onset asthma and hypersensitive reactions to cyclooxygenase-1 (COX-1) inhibitors. Among the available treatments for this disease, a combination of endoscopic sinus surgery followed by aspirin desensitization and aspirin maintenance therapy has been an effective approach. Studies have shown that long-term aspirin maintenance therapy can reduce the rate of nasal polyp recurrence in patients with N-ERD. However, the exact mechanism by which aspirin can both trigger and suppress airway disease in N-ERD remains poorly understood. In this review, we summarize current knowledge of aspirin effects in N-ERD, cardiovascular disease, and cancer, and consider potential mechanistic pathways accounting for the effects of aspirin in N-ERD.

Therapeutic candidates for keloid scars identified by qualitative review of scratch assay research for wound healing

The scratch assay is an in vitro technique used to analyze cell migration, proliferation, and cell-to-cell interaction. In the assay, cells are grown to confluence and then ‘scratched’ with a sterile instrument. For the cells in the leading edge, the resulting polarity induces migration and proliferation in attempt to ‘heal’ the modeled wound. Keloid scars are known to have an accelerated wound closure phenotype in the scratch assay, representing an overactivation of wound healing. We performed a qualitative review of the recent literature searching for inhibitors of scratch assay activity that were already available in topical formulations under the hypothesis that such compounds may offer therapeutic potential in keloid treatment. Although several shortcomings in the scratch assay literature were identified, caffeine and allicin successfully inhibited the scratch assay closure and inflammatory abnormalities in the commercially available keloid fibroblast cell line. Caffeine and allicin also impacted ATP production in keloid cells, most notably with inhibition of non-mitochondrial oxygen consumption. The traditional Chinese medicine, shikonin, was also successful in inhibiting scratch closure but displayed less dramatic impacts on metabolism. Together, our results partially summarize the strengths and limitations of current scratch assay literature and suggest clinical assessment of the therapeutic potential for these identified compounds against keloid scars may be warranted.

Matrix metalloproteinases and chronic rhinosinusitis with nasal polyposis. Unravelling a puzzle through a systematic review

BACKGROUND

The expression of metalloproteinases (MMPs) in chronic rhinosinusitis with nasal polyposis (CRSwNP) was reviewed in order to investigate their possible use as therapeutical targets and/or biomarkers.

METHODOLOGY

The differences between CRSwNP and normal controls or CRS without NP, as well as the effects of various treatments on MMPs, tissue inhibitors of MMPs (TIMPs) and MMP/TIMP ratios were considered as primary outcomes. Additional factors reported to affect MMP expression levels were noted as secondary outcomes. Data regarding inflammatory subtypes, patients’ clinical characteristics, controls, laboratory method(s) and origin of samples were also pooled. Studies on 10 or fewer patients or on specimens other than nasal and serum were excluded.

RESULTS

Forty-three studies were included. Tissue sample origin, allergic rhinitis, smoking, infection, medication intake and primary or recurrent disease should be considered as confounding factors for MMP levels. MMP-1 and -7 were consistently found to be significantly higher in CRSwNP patients than controls. CRSwNP endotypes with distinctly different inflammation patterns seem to present similar MMP-related remodelling patterns.

CONCLUSIONS

The existing literature has revealed several population and methodology related confounding factors and remains inconclusive regarding the roles of MMPs in CRSwNP pathophysiology and their possible clinical usefulness as biomarkers and therapeutical targets.

The Epithelial-Immune Crosstalk in Pulmonary Fibrosis

Interactions between the lung epithelium and the immune system involve a tight regulation to prevent inappropriate reactions and have been connected to several pulmonary diseases. Although the distal lung epithelium and local immunity have been implicated in the pathogenesis and disease course of idiopathic pulmonary fibrosis (IPF), consequences of their abnormal interplay remain less well known. Recent data suggests a two-way process, as illustrated by the influence of epithelial-derived periplakin on the immune landscape or the effect of macrophage-derived IL-17B on epithelial cells. Additionally, damage associated molecular patterns (DAMPs), released by damaged or dying (epithelial) cells, are augmented in IPF. Next to “sterile inflammation”, pathogen-associated molecular patterns (PAMPs) are increased in IPF and have been linked with lung fibrosis, while outer membrane vesicles from bacteria are able to influence epithelial-macrophage crosstalk. Finally, the advent of high-throughput technologies such as microbiome-sequencing has allowed for the identification of a disease-specific microbial environment. In this review, we propose to discuss how the interplays between the altered distal airway and alveolar epithelium, the lung microbiome and immune cells may shape a pro-fibrotic environment. More specifically, it will highlight DAMPs-PAMPs pathways and the specificities of the IPF lung microbiome while discussing recent elements suggesting abnormal mucosal immunity in pulmonary fibrosis.

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.

Level of sex hormones and their association with acetylsalicylic acid intolerance and nasal polyposis

BACKGROUND

Chronic rhinosinusitis may be associated with nasal polyposis. Recurrence of disease is often observed and may be due to an intolerance of acetylsalicylic acid. Sex hormones are known to modulate allergic reactions and inflammation. Whether they may be involved in the development and progression of nasal polyposis has not been investigated yet.

AIM

Examine the relationship between levels of sex hormones and nasal polyposis.

METHODS

Hormonal levels (estradiol, testosterone and progesterone) in patients with nasal polyposis (n = 26) with or without acetylsalicylic acid-intolerance were determined and compared to hormonal levels in patients with septal deviation (n = 35). Cone-beam computed tomography scans were analysed by using scores as defined by Lund and Mackay and by Kennedy.

RESULTS

Our results show a 5 times greater odds (p = 0.01) for developing nasal polyposis in the presence of lowered estradiol plasma levels than in the presence of normal / elevated levels. When analyzing females and males separately, a 6 times greater odds for females to develop nasal polyposis in the presence of lowered estradiol plasma levels was calculated (p = 0.02). Thus, females are more likely to develop nasal polyposis when they have lowered estradiol levels than males. In addition, female patients showed an increased risk for developing ASA intolerance (p = 0.01).

CONCLUSION

Variation of sex hormones may be involved in nasal polyposis. Further studies including more patients to validate the presented results are required.

SIGNIFICANCE

Retrospective clinical investigation suggesting a correlation between varying sex hormones and nasal polyposis.

Formation of nasal polyps: The roles of innate type 2 inflammation and deposition of fibrin

Chronic rhinosinusitis (CRS) is one of the most common chronic diseases worldwide. It is a heterogeneous disease, and geographical or ethnic differences in inflammatory pattern in nasal mucosa are major issues. Tissue eosinophilia in CRS is highly associated with extensive sinus disease, recalcitrance, and a higher nasal polyp (NP) recurrence rate after surgery. The prevalence of eosinophilic CRS (ECRS) is increasing in Asian countries within the last 2 decades, and this trend appears to be occurring across the world. International consensus criteria for ECRS are required for the accurate understanding of disease pathology and precision medicine. In a multicenter large-scale epidemiological survey, the "Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis study," ECRS was definitively defined when the eosinophil count in nasal mucosa is greater than or equal to 70 eosinophils/hpf (magnification, ×400), and this study proposed an algorithm that classifies CRS into 4 groups according to disease severity. The main therapeutic goal with ECRS is to eliminate or diminish the bulk of NP tissue. NPs are unique abnormal lesions that grow from the lining of the nasal and paranasal sinuses, and type 2 inflammation plays a critical role in NP development in patients with ECRS. An imbalance between protease and endogenous protease inhibitors might play a pivotal role in the initiation and exacerbation of type 2 inflammation in ECRS. Intraepithelial mast cells in NPs, showing a tryptase+, chymase- phenotype, may also enhance type 2 inflammation. Intense edema and reduced fibrosis are important histological features of eosinophilic NPs. Mucosal edema mainly consists of exuded plasma protein, and excessive fibrin deposition would be expected to contribute to the retention of proteins from capillaries and thereby perpetuate mucosal edema that may play an etiological role in NPs. Upregulation of the coagulation cascade and downregulation of fibrinolysis strongly induce abnormal fibrin deposition in nasal mucosa, and type 2 inflammation plays a central role in the imbalance of coagulation and fibrinolysis.

Histamine Induced Production of Chemokine CXCL8 Through H1R/PLC and NF-κB Signaling Pathways in Nasal Fibroblasts

Background and Objectives: Histamine has been suggested to play an important role during allergic and inflammatory reactions, affecting allergic rhinitis and chronic rhinosinusitis. CXCL8 is a pro-inflammatory chemokine and a critical factor that causes many airway inflammatory diseases including allergic rhinitis and chronic rhinosinusitis.Materials and Method: Histamine cytotoxicity was measured by MTT assay. Real-time polymerase chain reaction was used to identify histamine type 1 receptor in nasal fibroblasts. The fibroblasts were then treated with histamine with or without a histamine type 1 receptor antagonist and the CXCL8 protein was assessed using an enzyme-linked immunosorbent assay (ELISA). The downstream signaling molecules, including phospholipase C and phospho-p50, were evaluated by western blot and immunofluorescent staining.Results: Histamine had no significant cytotoxic effect until the concentration reached 1,000 μM. Histamine type 1 receptor mRNA was expressed in nasal fibroblasts. CXCL8 protein expression level was significantly increased following histamine stimulation. However, the expression level of CXCL8 decreased when phospholipase C was inhibited by U73122. Histamine increased phospho-p50 expression as seen in western blot results. The BAY11-7082, NF-κB inhibitor significantly reduced CXCL8 production in histamine-stimulated nasal fibroblasts.Conclusion: Histamine can induce the production of NF-κB controlled-chemokine CXCL8 by nasal fibroblasts, which supports a role for histamine in upper airway inflammatory diseases.

Contribution of Epithelial Cell Dysfunction to the Pathogenesis of Chronic Rhinosinusitis with Nasal Polyps

Background

In the past, the airway epithelium was thought to be primarily an inert physical barrier. We now know that the upper airway epithelium plays a critical role in both innate and adaptive immunity, and that epithelial dysfunction is strongly associated with inflammatory airway disease. The pathogenesis of chronic rhinosinusitis is poorly understood, but growing evidence supports a key role for the airway epithelium in the pathophysiology of the disease.

Objective

The purpose of this study is to explore our current understanding of how dysfunction in human sinonasal epithelial cells (HSNECs) contributes to the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP) and to examine how current and developing therapies affect epithelial cell functions.

Methods

A literature review of papers published in English pertaining to epithelial cell dysfunction in patients with CRSwNP was performed using the PubMed database. The search utilized combinations of the following key words: sinusitis, polyps, epithelium, pathophysiology, barrier function, dendritic cells, eosinophils, T cells, complement, mucociliary clearance, vitamin D, cytokines, chemokines, taste receptors, steroids, saline, and therapy.

Results

HSNEC mucociliary clearance, barrier function, secretion of cytokines, influence on dendritic cells, influence on T-cells, regulation of eosinophils, vitamin D metabolism, complement production, and taste receptor function are altered in patients with CRSwNP and contribute to the pathogenesis of the disease. Current therapies utilized to manage CRSwNP counteract the effects of HSNEC dysfunction and relieve key symptoms of the disease.

Conclusion

HSNECs are key players in both innate and adaptive immunity, and altered epithelial functions are closely intertwined with the pathogenesis of CRSwNP. Our review supports further investigation of altered HSNEC function in patients with CRSwNP and supports development of novel epithelial-targeted therapies for its management.

Fucoxanthin Inhibits Myofibroblast Differentiation and Extracellular Matrix Production in Nasal Polyp-Derived Fibroblasts via Modulation of Smad-Dependent and Smad-Independent Signaling Pathways

Nasal polyps (NPs) are a multifactorial disorder associated with a chronic inflammatory state of the nasal mucosa. Fucoxanthin (Fx) is a characteristic orange carotenoid obtained from brown algae and has diverse immunological properties. The present study investigated whether Fx inhibits fibrosis-related effects in nasal polyp-derived fibroblasts (NPDFs) and elucidated the molecular signaling pathways involved. The production of collagen type I (Col-1) was investigated in NP tissue via immunohistochemistry and western blot analysis. NPDFs were treated with transforming growth factor (TGF)-β1 (1 ng/mL) in the presence or absence of Fx (5⁻30 µM). The levels of α-smooth muscle actin (α-SMA), Col-1, and phosphorylated (p)-Smad 2/3, signal protein-1 (SP-1), MAPKs (mitogen-activated protein kinases), and Akt were measured by western blot analysis. The expression of Col-1 was detected in NP tissues. TGF-β1 stimulated the production of α-SMA and Col-1, and stimulated the contraction of collagen gel. However, pretreatment with Fx attenuated these effects. Furthermore, these inhibitory effects were mediated through modulation of both Smad 2/3 and Akt/SP-1 signaling pathways in TGF-β1-induced NPDFs. The results from the present study suggest that Fx may be a novel anti-fibrotic agent for the treatment of NP formation.

Effect of phlorotannins on myofibroblast differentiation and ECM protein expression in transforming growth factor β1‑induced nasal polyp‑derived fibroblasts

Phlorotannins (PTNs), a group of phenolic compounds from seaweeds, have diverse bioactivities. However, there has been no report on their antifibrotic effects during nasal polyp (NP) formation. In the present study, the effect of PTNs on transforming growth factor (TGF)‑β1‑induced profibrotic responses in nasal polyp‑derived fibroblasts (NPDFs) were determined and the relevant signaling pathways were investigated. The expression levels of collagen type‑1 (Col‑1) and fibronectin in NP tissues were measured by western blot analysis and immunohistochemistry. The NPDFs were treated with TGF‑β1 (1 ng/ml) in the presence or absence of PTNs (5‑30 µg/ml). The expression levels of α‑smooth muscle actin (α‑SMA), Col‑1, fibronectin, and phosphorylated‑small mothers against decapentaplegic (Smad)2/3 in NPDFs were measured by western blot analysis. The contractile activity of the NPDFs was determined by a collagen gel contraction assay. Col‑1 and fibronectin proteins were found to be expressed in NP tissues. PTNs had no significant cytotoxic effect on TGF‑β1‑induced NPDFs. TGF‑β1 induced the expression α‑SMA, Col‑1 and fibronectin, and stimulated fibroblast‑mediated contraction of collagen gel. However, pre‑treatment with PTNs inhibited the expression of these proteins. The inhibitory effects were mediated through the suppression of Smad2/3 signaling pathways in TGF‑β1‑induced NPDFs. These resulted suggested that PTNs may be important in inhibiting myofibroblast differentiation and extracellular matrix protein accumulation in NP formation through the Smad2/3 signaling pathway.

Role of Toll-like receptor 9 signaling on activation of nasal polyp-derived fibroblasts and its association with nasal polypogenesis

BACKGROUND

Nasal polyposis is characterized by persistent inflammation and remodeling in sinonasal mucosa. Toll-like receptor 9 (TLR9) is a DNA receptor of the innate immune system that plays a pivotal role in fibrosis and inflammatory responses. The aim of this study is to explore the expression, activity, and potential pathogenic role of TLR9 signaling in tissue remodeling in nasal polyp-derived fibroblasts (NPDFs).

METHODS

Fibrotic and inflammatory responses elicited by type A CpG oligonucleotides were examined in the NPDFs by a combination of real-time quantitative polymerase chain reaction, Western blot analysis, enzyme-linked immunosorbent assay, and immunofluorescence staining. For these experiments, the NPDFs were stimulated with different TLR9 agonists (CpG A and B) and blocked with inhibitors (MyD88 inhibitor and chloroquine).

RESULTS

TLR9 expression was significantly higher in nasal polyposis (NP) tissues compared to control or chronic rhinosinusitis (CRS) mucosa. In the NPDFs, TLR9 showed intracellular localization and expression of TLR9 was increased after treatment with CpG A. CpG A increased production of α-smooth muscle actin (α-SMA), fibronectin, and matrix metalloproteinases (MMPs) (MMP1, MMP2, and MMP9) in the NPDFs, while MyD88 inhibitor and chloroquine, which are known to block the TLR9 signaling pathway, inhibited their production. CpG A also produced type I interferons (IFN-α and IFN-β), which were inhibited by MyD88 inhibitor.

CONCLUSION

Our data indicates that CpG A-induced fibroblast activation and cytokine production were mediated via TLR9 stimulation in NPDFs. Disrupting this process with an inhibitor targeting TLR9 or its downstream signaling pathways could represent a novel approach to CRS with NP (CRSwNP) therapy.

Aberrant expression of miR-663 and transforming growth factor-β1 in nasal polyposis in children

The aim of the present study was to investigate the expression of microRNA (miR)-663 and its regulatory effects on the pathogenesis of nasal polyposis in children. Nasal polyp tissue, as well as serum and peripheral blood eosinophils were collected from 35 children diagnosed with nasal polypectomy between August 2013 and August 2015. As a control, the inferior nasal concha, serum and peripheral blood eosinophils were collected from 46 patients with nasal septal deviation complicated by inferior turbinate hypertrophy or patients with simple inferior turbinate hypertrophy who had undergone surgical removal of the inferior nasal concha. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to measure the expression of miR-663 and transforming growth factor-β1 (TGF-β1) in the nasal polyp tissue, serum and peripheral blood eosinophils of patients with nasal polyposis and controls. Western blotting was used to measure the expression of TGF-β1 protein in nasal tissue and eosinophils and an enzyme-linked immunosorbent assay was used to measure serum level of TGF-β1 protein. A dual luciferase reporter assay was used to determine whether TGF-β1 was a target gene of miR-663. Compared with the control group, levels of TGF-β1 mRNA and protein were significantly increased in all three types of specimens from pediatric patients with nasal polyposis (P<0.05). miR-663 expression was significantly decreased in nasal polyp tissue and peripheral blood eosinophils (P<0.05). The dual luciferase reporter assay confirmed that TGF-β1 was a target gene of miR-663. The current study suggests that the upregulation of TGF-β1 may be associated with the downregulation of miR-663 in nasal polyposis in children. miR-663 may have regulatory effects on the pathogenesis of nasal polyposis by regulating TGF-β1 and may be developed as a genetic marker of nasal polyposis in children.