Inflammation In Chronic Rhinosinusitis Research Articles

SIRT5 exacerbates eosinophilic chronic rhinosinusitis by promoting polarization of M2 macrophage

BackgroundPrevious study implied that local M2 polarization of macrophage promoted mucosal edema and exacerbates Th2 type inflammation in chronic rhinosinusitis with nasal polyps (CRSwNP). However, the specific pathogenic role of M2 macrophages and the intrinsic regulators in the development of CRS remains elusive. ObjectiveWe thought to investigate the regulatory role of SIRT5 in the polarization of M2 macrophages and its potential contribution to the development of CRSwNP. MethodsRT-qPCR and Western blot analyses were performed to examine the expression levels of SIRT5 and markers of M2 macrophages in sinonasal mucosa samples obtained from both CRS and control groups. Wild-type and Sirt5 knockout mice were used to establish nasal polyp model with Th2 inflammation and investigate the effects of SIRT5 in macrophages on disease development. Furthermore, in vitro experiments were conducted to elucidate the regulatory role of SIRT5 in polarization of M2 macrophages. ResultsClinical investigations showed that SIRT5 was highly expressed and positively correlated with M2 macrophages markers in eosinophilic polyps. The expression of SIRT5 in M2 macrophages was found to contribute to the development of the disease, which was impaired in Sirt5 deficiency mice. Mechanistically, SIRT5 was shown to enhance the alternative polarization of macrophages through promoting glutaminolysis. ConclusionsSIRT5 plays a crucial role in promoting the development of CRSwNP by supporting the alternative polarization of macrophage and thus provides a potential target for CRSwNP interventions.

The interleukin-4/interleukin-13 pathway in type 2 inflammation in chronic rhinosinusitis with nasal polyps.

Chronic rhinosinusitis with nasal polyps (CRSwNP) is predominantly a type 2 inflammatory disease associated with type 2 (T2) cell responses and epithelial barrier, mucociliary, and olfactory dysfunction. The inflammatory cytokines interleukin (IL)-4, IL-13, and IL-5 are key mediators driving and perpetuating type 2 inflammation. The inflammatory responses driven by these cytokines include the recruitment and activation of eosinophils, basophils, mast cells, goblet cells, M2 macrophages, and B cells. The activation of these immune cells results in a range of pathologic effects including immunoglobulin E production, an increase in the number of smooth muscle cells within the nasal mucosa and a reduction in their contractility, increased deposition of fibrinogen, mucus hyperproduction, and local edema. The cytokine-driven structural changes include nasal polyp formation and nasal epithelial tissue remodeling, which perpetuate barrier dysfunction. Type 2 inflammation may also alter the availability or function of olfactory sensory neurons contributing to loss of sense of smell. Targeting these key cytokine pathways has emerged as an effective approach for the treatment of type 2 inflammatory airway diseases, and a number of biologic agents are now available or in development for CRSwNP. In this review, we provide an overview of the inflammatory pathways involved in CRSwNP and describe how targeting key drivers of type 2 inflammation is an effective therapeutic option for patients.

Identification of neutrophils and eosinophils in upper airway mucosa with immunofluorescence multiplex image cytometry.

Characterization of inflammation in chronic rhinosinusitis with (CRSwNP) and without nasal polyps (CRSsNP) is an ongoing research process. To overcome limitations of current cytologic techniques, we investigated whether immunofluorescence multiplex image cytometry could quantify intact neutrophils, eosinophils, and other immune cells in solid upper airway mucosa. We used a four-channel immunofluorescence-microscopy technique for the simultaneous detection of the leukocyte marker CD45, the neutrophil marker myeloperoxidase, two eosinophil markers, i.e., major basic protein and eosinophil peroxidase, and DAPI (4',6-diamidin-2-phenylindole), in formalin-fixed paraffin-embedded upper airway tissue samples of patients with CRSwNP and CRSsNP, as well as of patients free of CRS with inferior turbinate hypertrophy (controls). Image acquisition and analysis were performed with TissueFAXS and StrataQuest (TissueGnostics, Vienna, Austria), respectively. Positive and negative immunostaining were differentiated with a specific fluorescence signal/background signal ratio. Isotype controls were used as negative controls. In six controls, nine patients with CRSsNP, and 11 patients with CRSwNP, the median area scanned and median cell count per patient were 14.2mm2 and 34,356, respectively. In CRSwNP, the number of eosinophils was three times higher (23%) than that of neutrophils (7%). Three times more immune cells were encountered in CRSwNP (33%) compared to CRSsNP (11%). In controls, inflammation was balanced between the epithelial layer and lamina propria, in contrast to CRS (three times more pronounced inflammation in the lamina propria). The quantification of intact neutrophils, eosinophils, and other immune cells in solid tissue with undisrupted architecture seems feasible with immunofluorescence multiplex image cytometry.

Epithelium-derived kallistatin promotes CD4+ T-cell chemotaxis to TH2-type inflammation in chronic rhinosinusitis

The function of kallistatin in airway inflammation, particularly chronic rhinosinusitis with nasal polyps (CRSwNP), has not been elucidated. We sought to investigate the role of kallistatin in airway inflammation. Kallistatin and proinflammatory cytokine expression levels were detected in nasal polyps. For the invivo studies, we constructed the kallistatin-overexpressing transgenic mice to elucidate the role of kallistatin in airway inflammation. Furthermore, the levels of plasma IgE and proinflammatory cytokines in the airways were evaluated in the kallistatin-/- rat invivo model under a type 2 inflammatory background. Finally, the Notch signaling pathway was explored to understand the role of kallistatin in CRSwNP. We showed that the expression of kallistatin was significantly higher in nasal polyps than in the normal nasal mucosa and correlated with IL-4 expression. We also discovered that the nasal mucosa of kallistatin-overexpressing transgenic mice expressed higher levels of IL-4 expression, associating to TH2-type inflammation. Interestingly, we observed lower IL-4 levels in the nasal mucosa and lower total plasma IgE of the kallistatin-/- group treated with house dust mite allergen compared with the wild-type house dust mite group. Finally, we observed a significant increase in the expression of Jagged2 in the nasal epithelium cells transduced with adenovirus-kallistatin. This heightened expression correlated with increased secretion of IL-4, attributed to the augmented population of CD4+CD45+Notch1+ T cells. These findings collectively may contribute to the induction of TH2-type inflammation. Kallistatin was demonstrated to be involved in the CRSwNP pathogenesis by enhancing the TH2 inflammation, which was found to be associated with more expression of IL-4, potentially facilitated through Jagged2-Notch1 signaling in CD4+ T cells.

Induction of a type 2 inflammatory chronic rhinosinusitis in C57BL/6 mice

Background: Eosinophilic chronic rhinosinusitis (CRS) has been widely studied for its intractability and high recurrence rate. It can be divided into pure and mixed type 2 CRS subtypes. Mouse models that reflect pure type 2 inflammation of CRS are lacking. Objective: This study aims to establish a relatively pure type 2 CRS mouse model and compare it with 2 mixed type 2 CRS models. Methods: Three mouse CRS models were constructed: (1) aerosol ovalbumin (OVA) + aspergillus oryzae-derived protease (AP); (2) intranasal OVA + AP; (3) Intraperitoneal then intranasal OVA + AP (n = 10 per group). Nasal, lung symptoms, IgE, inflammatory cells, cytokines, and remodeling factors were evaluated. Results: Histological and micro-computed tomography showed inflammation, polyps, and opacification in all 3 experimental groups. The aerosol group had significantly increased local eosinophils and type 2 cytokines, while other types of cytokines showed no noticeable change. The nasal instillation groups also showed elevated other inflammatory factors and tissue polypoid changes were more pronounced. More severe pulmonary inflammation was observed with aerosol delivery. Conclusion: Aerosol inhalation mouse model is superior for studying nasal relatively pure type 2 inflammation and lower airway comorbidities.

Hypoxia-inducible factor 1α activates the NLRP3 inflammasome to regulate epithelial differentiation in chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is an upper airway inflammation disease associated with hypoxia-mediated inflammation. The effect of hypoxia-inducible factor 1α (HIF-1α) on NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome activation in the pathogenesis of sinonasal mucosa is unclear. We investigated the effect and mechanism of HIF-1α on NLRP3 inflammasome activation in the primary human nasal epithelial cells (hNECs). We measured the expression levels of HIF-1α and the NLRP3 inflammasome in nasal biopsy samples and hNECs derived from negative controls (healthy) and patients with CRS with and without nasal polyps, then further analyzed the specific mechanism of HIF-1α regulation of the NLRP3 inflammasome and its effect on hNEC differentiation. Increased mRNA and protein expression levels of HIF-1α and the NLRP3 inflammasome were found in all CRS biopsy samples. HIF-1α enhanced expression of phosphorylated NLRP3 (S295) in both HEK293T cells and hNECs; it also promoted recruitment of caspase-1 and apoptotic speck-like protein containing caspase recruitment domain (aka ASC) by NLRP3. HIF-1α also improved NLRP3's stability by preventing NLRP3 degradation caused by hypoxia-mediated inflammation. In addition, HIF-1α could also increase expression of Mucin5AC and decrease expression of α-tubulin by promoting activation of the NLRP3 inflammasome in hNECs. In addition, HIF-1α could also directly promote P63 expression in hNECs. HIF-1α could potentially induce cilia loss and enhance the proliferation of goblet cells, possibly mediated by the regulation of NLRP3 phosphorylation in CRS inflammation.

The interplay of inflammation and remodeling in the pathogenesis of chronic rhinosinusitis: current understanding and future directions.

Chronic rhinosinusitis (CRS), a common clinical condition characterized by persistent mucosal inflammation and tissue remodeling, has a complex pathogenesis that is intricately linked to innate and adaptive immunity. A number of studies have demonstrated that a variety of immune cells and cytokines that play a vital role in mediating inflammation in CRS are also involved in remodeling of the nasal mucosa and the cells as well as different cytokines involved in remodeling in CRS are also able to exert some influence on inflammation, even though the exact relationship between inflammation and remodeling in CRS has not yet been fully elucidated. In this review, the potential role of immune cells and cytokines in regulating inflammation and remodeling of CRS mucosa has been described, starting with the immune cells and cytokines that act together in inflammation and remodeling. The goal is to aid researchers in understanding intimate connection between inflammation and remodeling of CRS and to offer novel ideas for future research.

Non-Type 2 and Mixed Inflammation in Chronic Rhinosinusitis and Lower Airway Disease.

The aim was to discuss the role of non-type 2 inflammation in patients diagnosed with chronic rhinosinusitis (CRS) and comorbid lower airway disease. Medline, Embase, National Institute for Health and Care Excellence, TRIP Database, ProQuest, Clinicaltrials.gov, Cochrane Central Registry of Controlled Trials, Web of Science, government and health organizations, and graduate-level theses. This scoping review followed PRISMA-ScR guidelines. Search strategy was peer-reviewed by medical librarians. Studies were included if they utilized airway sampling, non-type 2 cytokines, and patients with CRS and lower airway disease. Twenty-seven from 7060 articles were included. In patients with CRS and comorbid asthma, aspirin-exacerbated respiratory disease (AERD), and chronic obstructive pulmonary disease (COPD)/bronchiectasis, 60% (n = 12), 33% (n = 2), and 100% (n = 1), respectively, demonstrated mixed or non-type 2 endotypes. Comorbid CRS and asthma produced type 1 (n = 1.5), type 2 (n = 8), type 3 (n = 1), mixed type 1/2 (n = 1), and mixed type 1/2/3 (n = 8.5) endotype shifts. AERD demonstrated type 2 (n = 4), mixed type 2/3 (n = 1), and mixed type 1/2/3 (n = 1) endotype shifts. CRS with COPD or bronchiectasis demonstrated a mixed 1/2 (n = 1) endotype shift. Type 2 disease has been extensively reviewed due to advent biologics targeting type 2 inflammation, but outcomes may be suboptimal due to the presence of non-type 2 inflammation. A proportion of patients with CRS and comorbid lower airway disease demonstrated mixed and non-type 2 endotype shifts. This emphasizes that patients with unified airway disease may have forms of inflammation beyond classical type 2 disease which could inform biologic development. Laryngoscope, 134:1005-1013, 2024.

The Correlation of Tissue’s Endotype Biomarkers and Dominant Inflammation Cell in Chronic Rhinosinusitis

Background and Objectives This study analyzes the relationship between endotype biomarkers and the type of tissue inflammation in chronic rhinosinusitis (CRS) in order to obtain a more accurate division of disease groups and appropriate therapy.Subjects and Method We carried out a cross-sectional study involving 33 samples of CRS patients. We conducted enzyme-linked immunosorbent assay to examine endotype biomarkers and histopathology methods to examine tissue inflammation.Results Statistical analysis with an independent t-test showed significant differences with respect to eosinophil cationic protein (ECP) between the eosinophilic and neutrophilic groups (p<0.05), whereas there were no significant differences between the two groups (p>0.05) with respect to Charcot-Leyden crystal (CLC), interleukin-5 (IL-5), interferon gamma (IFN-γ), interleukin- 17A (IL-17A), and oncostatin M (OSM). The Spearman test showed also showed that ECP, CLC, IL-5, IL-17A, IFN-γ and OSM had no significant correlation with the two groups (p>0.05). The receiver operating characteristics analysis showed the optimal cut-off value of ECP of 342.22 pg/mL with sensitivity and specificity of 72.7% for determining the inflammation type (area under cover=0.78, p=0.009).Conclusion The higher level of ECP was more likely to be found in the eosinophilic tissue inflammation. Consequently, we propose using ECP as the main biomarker to identify the CRS type 2. Further research with a larger sample size is required for cut-off points of ECP in order to determine the endotype of CRS.

Systemic administration of budesonide in pegylated liposomes for improved efficacy in chronic rhinosinusitis.

Chronic rhinosinusitis (CRS) is a chronic inflammatory condition affecting the nasal and paranasal sinuses of approximately 11.5% of the United States adult population. Oral corticosteroids are effective in controlling sinonasal inflammation in CRS, but the associated adverse effects limit their clinical use. Topical budesonide has demonstrated clinical efficacy in patients with CRS. Herein, we investigated the systemic delivery of liposomes tethered with poly(ethylene glycol) (PEG) and loaded with budesonide in a murine model of CRS. PEGylated liposomes encapsulated with budesonide phosphate (L-BudP) were administered via tail vein injection, and the feasibility of L-BudP to reduce sinonasal inflammation was compared to that of free budesonide phosphate (F-BudP) and topical budesonide phosphate (T-BudP) treatment over a 14-day study period. Compared to a single injection of F-BudP and repeat T-BudP administration, a single injection of L-BudP demonstrated increased and prolonged efficacy, resulting in the significant improvement of sinonasal tissue histopathological scores (p<0.05) with decreased immune cell infiltration (p<0.05). Toxicities associated with L-BudP and T-BudP treatment, assessed via body and organ weight, as well as peripheral blood liver enzyme and differential white blood cell analyses, were transient and comparable. These data suggest that systemic liposomal budesonide treatment results in improved efficacy over topical treatment.

Nanotechnology-enabled topical delivery of therapeutics in chronic rhinosinusitis.

Chronic rhinosinusitis (CRS) is a chronic inflammatory disease of the paranasal sinuses which represents a significant health burden due to its widespread prevalence and impact on patients' quality of life. As the molecular pathways driving and sustaining inflammation in CRS become better elucidated, the diversity of treatment options is likely to widen significantly. Nanotechnology offers several tools to enhance the effectiveness of topical therapies, which has been limited by factors such as poor drug retention, mucosal permeation and adhesion, removal by epithelial efflux pumps and the inability to effectively penetrate biofilms. In this review, we highlight the successful application of nanomedicine in the field of CRS therapeutics, discuss current limitations and propose opportunities for future work.

Incidence of hypocortisolism with long-term budesonide irrigation for chronic rhinosinusitis.

Budesonide irrigations (BIs) are commonly used to control inflammation in chronic rhinosinusitis (CRS). In 2016 we reported an analysis of long-term BI with regard to hypothalamic-pituitary-adrenal axis function. We present a follow-up analysis in a larger cohort of patients with longer follow-up. Patients were candidates for stimulated cortisol testing after regularly performing BI for CRS at least daily for ≥6 months. We retrospectively evaluated all patients who received stimulated cortisol testing at our center between 2012 and 2022. We correlated cortisol levels with the use of BI and other forms of corticosteroids. We analyzed 401 cortisol test results in 285 patients. The mean duration of use was 34 months. Overall, 21.8% of patients were hypocortisolemic (<18 ug/dL) at first test. In patients who used only BI, the rate of hypocortisolemia was 7.5%, whereas in patients who also used concurrent oral and inhaled corticosteroids, the rate was 40% to 50%. Lower cortisol levels were associated with male sex (p<0.0001) and concomitant use of oral and inhaled steroids (p<0.0001). Duration of BI use was not significantly associated with lower cortisol levels (p=0.701), nor was greater dosing frequency (p=0.289). Prolonged use of BI alone is not likely to cause hypocortisolemia in the majority of patients. However, concomitant use of inhaled and oral steroids and male sex may be associated with hypocortisolemia. Surveillance of cortisol levels may be considered in vulnerable populations who use BI regularly, particularly in patients using other forms of corticosteroids with known systemic absorption.

MiR-200a-3p regulates epithelial-mesenchymal transition and inflammation in chronic rhinosinusitis with nasal polyps by targeting ZEB1 via ERK/p38 pathway.

Several biological processes are regulated by miR-200a-3p, including cell proliferation, migration, and epithelial-mesenchymal transition (EMT). In this study we aimed to uncover the diagnostic value and molecular mechanisms of miR-200a-3p in chronic rhinosinusitis with nasal polyps (CRSwNP). The expressions of miR-200a-3p were detected by quantitative real-time polymerase chain reaction (qRT-PCR), Zinc finger E-box binding homeobox 1 (ZEB1) levels were examined by qRT-PCR and immunofluorescence staining. The interaction between miR-200a-3p and ZEB1 was predicted by TargetScan Human 8.0 and confirmed by dual-luciferase reporter assays. In addition, the effect of miR-200a-3p and ZEB1 on EMT-related makers and inflammation cytokines was assessed by qRT-PCR and Western blotting in human nasal epithelial cells (hNEpCs) and primary human nasal mucosal epithelial cells (hNECs). We found that miR-200a-3p was downregulated in non-eosinophilic and eosinophilic CRSwNP patients when compared with controls. The diagnostic value of miR-200a-3p in serum is reflected by the receiver operating characteristic curve and the 22-item Sino-Nasal Outcome Test. Bioinformatic analysis and luciferase reporter assay identified ZEB1 as a target of miR-200a-3p. ZEB1 was more highly expressed in CRSwNP than in controls. Furthermore, miR-200a-3p inhibitor or ZEB1 overexpression significantly suppressed the epithelial marker E-cadherin; promoted the activation of vimentin, α-spinal muscle atrophy, and N-cadherin; and aggravated inflammation in hNEpCs. Knockdown of ZEB1 significantly alleviated the cellular remodeling caused by miR-200a-3p inhibitor via the extracellular signal-regulated kinase (ERK)/p38 pathway in hNECs. miR-200a-3p suppresses EMT and inflammation by regulating the expression of ZEB1 via the ERK/p38 pathway. Our study presents new ideas for protecting nasal epithelial cells from tissue remodeling and finding a possible target for disease.

Impact of Nasal Cavity CT Opacification Upon Sinonasal Quality of Life.

Current methods of quantifying inflammation in chronic rhinosinusitis (CRS) on computed tomography (CT) imaging focus on opacification of the paranasal sinuses and show limited correlation with patient-reported outcome measures. This study aimed to determine if quantifying CT opacification of the nasal cavity correlated with Sino-Nasal Outcomes Test scores (SNOT-22). Thirty patients with CRS were enrolled. Lund-Mackay and SNOT-22 scores were measured. Nasal cavity regions of interest (ROIs) were measured by 2 independent raters using ImageJ at 3 points on coronal CT scans: anteriorly at the lacrimal duct, at the approximate midpoint demarcated by the posterior aspect of the globe, and posteriorly at the transition from the hard to soft palate. Superior and inferior regions were defined based upon the root of the inferior turbinate. Percent opacification was calculated for each ROI. Analyses were conducted bilaterally and for the side with greater opacification (worse side). Interrater reliability was strong for all ROIs. Lund-Mackay scores correlated with nasal blockage only (r = .495, P = .01) and did not correlate with nasal cavity ROI opacification. Inferior nasal cavity opacification for worse-sided anterior ROI and middle ROI correlated with SNOT-22 scores for nasal blockage (anterior r = .41, P = .03) (middle r = .42, P = .023) and runny nose (anterior r = .44, P = .02) (middle r = .38, P = .04). Posterior ROIs did not correlate with SNOT-22. Traditional CT scoring of sinus opacification does not correlate well with nasal cavity opacification or SNOT-22. Inferior nasal cavity inflammation provides unique correlations with SNOT-22 nasal questions and may guide targeted interventions in these regions.

Eosinophil, mast cell and basophil microparticle in nasal lavage fluids as potential biomarkers for type 2 inflammation in chronic rhinosinusitis with nasal polyps

Microparticles (MP) are large extracellular vesicles (0.5-1.0μm) that are released from activated cells. Eosinophils, mast cells and basophils play roles in type 2 inflammation in nasal mucosa in chronic rhinosinusitis with nasal polyps (CRSwNP).

Testing specialized pro-resolving mediators on bacteria-derived inflammation in chronic rhinosinusitis

Background and Hypothesis:Chronic rhinosinusitis (CRS) is defined by chronic tissue inflammation, and prior work in the field implicates activation of the NFκb pathway. This pathway is activated by pattern recognition receptors (PRRs), which recognize molecules associated with pathogens and cellular damage. In CRS subjects, particularly those with nasal polyps, dysregulated pro-resolving processes have been documented. Specialized pro-resolving lipid mediators (SPMs), including lipoxin A4 and the resolvins, are prime targets for active resolution of the chronic tissue inflammation that defines the disease. We hypothesize that exaggerated pro-inflammatory responses to CRS tissues could be mitigated by application of SPMs in vitro. Project Methods:CRS polyp tissue was collected from surgical specimens, and submerged in cell culture conditions with 10 ug/ml lipopolysaccharide (LPS) or lipoteichoic acid (LTA) to mimic bacterial pathogens commonly observed in CRS (i.e., P. aeruginosa or S.aureus). Tissues were treated with 50 nM of SPMs, either lipoxin A4, resolvin D1, or resolvin D2. RNA was isolated from treated tissues. RNA was analyzed with Taqman Microarray NF-kB human pathway RT-PCR panel to evaluate expression of NF-kB-associated genes. In tandem, supernatant was collected for analysis of cytokine and chemokine signaling proteins. Protein assays were performed using the Luminex Multiplex Assay to observe modulation of pro-inflammatory immune signaling molecules Results:LPS and LTA exposures demonstrated robust and different pro-inflammatory responses in ex vivo nasal polyp tissue. Treatment with SPMs was able to at least partially reduce NF-kB activation and the associated inflammatory response at a molecular level. Conclusion:Inflammation is a complex, temporally precise physiologic process. In chronic inflammatory mucosal diseases such as CRS, repeated acute insults may lead to chronic tissue inflammation. A novel treatment approach leveraging endogenous tissue resolving processes, i.e., SPMs was tested here in vitro and demonstrates potential promise for CRS with nasal polyps.

Microbial metabolite succinate activates solitary chemosensory cells in the human sinonasal epithelium.

Succinate, although most famous for its role in the Krebs cycle, can be released extracellularly as a signal of cellular distress, particularly in situations of metabolic stress and inflammation. Solitary chemosensory cells (SCCs) express SUCNR1, the succinate receptor, and modulate type 2 inflammatory responses in helminth and protozoal infections in the small intestine. SCCs are the dominant epithelial source of interleukin-25, as well as an important source of cysteinyl leukotrienes in the airway, and have been implicated as upstream agents in type 2 inflammation in chronic rhinosinusitis (CRS) and asthma. In this study, we used scRNAseq analysis, live cell imaging of intracellular calcium from primary sinonasal air-liquid interface (ALI) cultures from 1 donor, andmeasure antimicrobial peptide release from 5 donors to demonstrate preliminary evidence suggesting that succinate can act as a stimulant of SCCs in the human sinonasal epithelium. Results from scRNAseq analysis show that approximately 10% of the SCC/ionocyte cluster of cells expressed SUCNR1 as well as a small population of immune cells. Using live cell imaging of intracellular calcium, we also demonstrate that clusters of cells on primary sinonasal ALI cultures initiated calcium-mediated signaling in response to succinate stimulation. Furthermore, we present evidence that primary sinonasal ALI cultures treated with succinate had increased levels of apical beta-defensin 2, an antimicrobial peptide, compared to treatment with a control solution. Overall, these findings demonstrate the need for further investigation into the activation of the sinonasal epithelium by succinate in the pathogenesis of CRS.

Evidence that oncostatin M synergizes with IL-4 signaling to induce TSLP expression in chronic rhinosinusitis with nasal polyps

Oncostatin M (OSM) may promote type 2 inflammation in chronic rhinosinusitis with nasal polyps (CRSwNP) by inducing thymic stromal lymphopoietin (TSLP). We sought to study the impact of OSM on TSLP synthesis and release from nasal epithelial cells (NECs). OSM receptors, IL-4 receptors (IL-4R), and TSLP were evaluated in mucosal tissue and primary NECs from patients with CRSwNP by quantitative PCR and immunofluorescence. Air-liquid interface-cultured NECs were stimulated with cytokines, including OSM, and quantitative PCR, ELISA, Western blot, and flow cytometry were used to assess the expression of OSM receptors, IL-4R, and TSLP. Increased levels of OSM receptor β chain (OSMRβ), IL-4Rα, and TSLP were observed in nasal polyp tissues and primary epithelial cells from nasal polyps of patients with CRSwNP compared with control tissues or cells from control subjects. The level of expression of OSMRβ in tissue was correlated with levels of both IL-4Rα and TSLP. OSM stimulation of NECs increased the expression of OSMRβ and IL-4Rα. Stimulation with IL-4 plus OSM augmented the production of TSLP; the response was suppressed by a signal transducer and activator of transcription 6 inhibitor. Stimulation of NECs with IL-4 plus OSM increased the expression of proprotein convertase subtilisin/kexin 3, an enzyme that truncates and activates TSLP. OSM increases the expression of IL-4Rα and synergizes with IL-4 to induce the synthesis and release of TSLP in NECs. Because the combination of IL-4 and OSM also augmented the expression of proprotein convertase subtilisin/kexin 3, these results suggest that OSM can induce both synthesis and posttranslational processing/activation of TSLP, promoting type 2 inflammation.

Infection and inflammation in chronic rhinosinusitis: Gene ontology/pathway analysis perspective.

Infection and inflammation in chronic rhinosinusitis: Gene ontology/pathway analysis perspective.

Sinonasal Biomarkers Defining Type 2-High and Type 2-Low Inflammation in Chronic Rhinosinusitis with Nasal Polyps.

The complex pathophysiology of chronic rhinosinusitis with nasal polyps (CRSwNP) generates a spectrum of phenotypes with a wide variety of inflammatory states. We enrolled 44 very-likely-to-be type 2 CRSwNP patients in order to evaluate the load of inflammation and to analyze human interleukins in nasal secretion. Clinical data were collected to evaluate the severity of the disease. High levels of IL-5, IL-4, IL-6, and IL-33 were detected in all type 2 CRSwNP patients. By analyzing type 2 cytokine profiles and local eosinophil count, we identified two coherent clusters: the first was characterized by high levels of IL-4, IL-5, IL-6, and a high-grade eosinophil count (type 2-high); the second had lower levels of cytokines and poor or absent eosinophilic inflammation (type-2 low). IL-5 levels were significantly higher within the type 2 cytokine and it was the most reliable biomarker for differentiating the two clusters. In type 2-high inflammatory profile clinical scores, the mean number of previous surgeries and need for systemic corticosteroids were significantly higher compared to type 2-low. Our research demonstrated the potential role of type 2 biomarkers, and in particular, of IL-5 in identifying patients with a more severe phenotype based on a high inflammatory load.