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Background: SERPINB2, a biomarker of Type-2 (T2) inflammatory processes, has been described in the context of asthma. Chronic rhinosinusitis with nasal polyps (CRSwNP) is also correlated with T2 inflammation and elevated 15LO1 induced by IL-4/13 in nasal epithelial cells. The aim of this study was to evaluate the expression and location of SERPINB2 in nasal epithelial cells (NECs) and determine whether SERPINB2 regulates 15LO1 and downstream T2 markers in NECs via STAT6 signalling., Methods: SERPINB2 gene expression in bulk and single-cell RNAseq database was analysed by bioinformatics analysis. SERPINB2, 15LO1 and other T2 markers were evaluated from CRSwNP and HCs NECs. The colocalization of SERPINB2 and 15LO1 was evaluated by immunofluorescence. Fresh NECs were cultured at an air-liquid interface with or without IL-13, SERPINB2 Dicer-substrate short interfering RNAs (DsiRNAs) transfection, exogenous SERPINB2, 15-HETE recombinant protein and pSTAT6 inhibitors. 15LO1, 15-HETE and downstream T2 markers were analysed by qRT-PCR, western blot and ELISA., Results: SERPINB2 expression was increased in eosinophilic nasal polyps compared with that in noneosinophilic nasal polyps and control tissues and positively correlated with 15LO1 and other downstream T2 markers. SERPINB2 was predominantly expressed by epithelial cells in NP tissue and was colocalized with 15LO1. In primary NECs in vitro, SERPINB2 expression was induced by IL-13. Knockdown or overexpression SERPINB2 decreased or enhanced expression of 15LO1 and 15-HETE in NECs, respectively, in a STAT6-dependent manner. SERPINB2 siRNA also inhibited the expression of the 15LO1 downstream genes, such as CCL26, POSTN and NOS2. STAT6 inhibition similarly decreased SERPINB2-induced 15LO1., Conclusions: SERPINB2 is increased in NP epithelial cells of eosinophilic CRSwNP (eCRSwNP) and contributes to T2 inflammation via STAT6 signalling. SERPINB2 could be considered a novel therapeutic target for eCRSwNP., (© 2024 The Authors. Clinical & Experimental Allergy published by John Wiley & Sons Ltd.)

Background: No studies have investigated the systemic and local sinonasal profile of obesity-related chronic rhinosinusitis (CRS), despite its observed association in recent retrospective studies. The objectives of our study were to assess the impact of obesity on the clinical and cytokine profile of patients with CRS and evaluate treatment response with functional endoscopic sinus surgery., Methods: This was a prospective observational study at the Cleveland Clinic that included patients with CRS (n = 54) between December 2021 and September 2022. Data collection included demographics, body mass index (BMI), comorbidities, baseline sinonasal outcome test scores, baseline radiologic scores (Lund-Mackay), postoperative sinonasal outcome test scores (at 3-4 months), and local and systemic alarmins/T-helper cytokines., Results: Out of the 54 CRS patients, there were 20 CRS patients without nasal polyps (37%) and 34 with nasal polyps (63%). Patients were categorized based on obesity (BMI ≥ 30 kg/m 2 ). Obese CRS patients had lower systemic alarmins (interleukin [IL]-33 and Thymic stromal lymphopoietin (TSLP)) compared to non-obese CRS patients (IL-33: 744.2 ± 1164.6 pg/mL vs. 137.5 ± 320.0 pg/mL, p = 0.005; TSLP: 627.7 ± 1806.3 pg/mL vs. 28.1 ± 85.4 pg/mL, p = 0.017). CRS patients with nasal polyps with BMI ≥30 kg/m 2 had higher postoperative sinonasal outcome test scores and lower levels of nasal eotaxin-3 and IL-33 compared to BMI <30 kg/m 2 counterparts., Conclusions: In conclusion, patients with obese CRS and nasal polyps displayed diminished levels of intranasal alarmins and reduced intranasal eotaxin-3. These results potentially imply the presence of a unique, obese type 2-low CRS phenotype that warrants further exploration., (© 2023 ARS‐AAOA, LLC.)

Eosinophil extracellular traps (EETs) are implicated in various eosinophil-associated diseases; however, their role in chronic rhinosinusitis (CRS) remains unclear. In the present study, 57 CRS patients were enrolled, and immunofluorescence was used to analyze EETs in eosinophilic (eCRS) and non-eosinophilic (Non-eCRS) tissues. MSD was used to examine IL-4, IL-5, and IL-13 concentrations in tissue homogenates. Charcot-Leyden crystals (CLCs) protein expression was detected in PMA, PMA+DNase I, and blank control eosinophils using ELISA. Eotaxin-3 mRNA and protein levels were measured in human nasal epithelial cells (HNECs) cultured with EETs, EETs+DNase I, DNase I, and unstimulated eosinophils using PCR and ELISA. EETs were significantly increased in eCRS tissues compared with Non-eCRS (P<0.001), and correlated with VAS and Lund-Mackay CT scores. IL-5 expression was related to EETs formation (r = 0.738, P<0.001). PMA-stimulated eosinophils exhibited higher CLCs protein levels (P<0.01). Co-culturing HNECs with EETs significantly increased eotaxin-3 mRNA and protein levels (P<0.0001, P<0.001) compared with other groups. The study suggests EETs formation is elevated in eCRS patients and is involved in CLCs formation and chemokine secretion, promoting eosinophilic inflammation., (© 2024 The Author(s).)

Background: In mice models, eosinophils have been divided into different subpopulations with distinct phenotypes and functions, based on CD62L and CD101 patterns of membrane expression. Limited data are available in humans., Objective: To investigate eosinophils subpopulations in peripheral blood (PB) and nasal polyp tissue (NP) from severe eosinophilic asthma (SEA) patients plus concomitant chronic rhinosinusitis with nasal polyps (CRSwNP)., Methods: We recruited 23 SEA patients (14 with CRSwNP); as controls, we enrolled 15 non-severe asthma patients, 15 allergic rhinitis patients without asthma and 15 healthy donors. Eosinophils were isolated from PB and NP and analysed by FACS. Eotaxin-3 and eotaxin-1 mRNA expression in NP tissue was also evaluated., Results: A significantly higher percentage of circulating CD62L low cells was observed in SEA, as compared with controls, expressing higher levels of CCR3, CD69 and lower levels of CD125 (IL-5R), CRTH2, CD86 and CD28 in comparison with CD62L bright cells. In NP, eosinophils showed a high proportion of CD62L low phenotype, significantly greater than that observed in PB. Surface expression of IL-3R, IL-5R, CD69 and CD86 was significantly higher in CD62L low eosinophils from NP than in those from blood. Moreover, eotaxin-3 mRNA expression positively correlated with the percentage of CD62L low cells in NP., Conclusion: Two different eosinophil subphenotypes can be identified in blood and NP of SEA patients, with a preferential accumulation of CD62L low inflammatory cells in NP., (© 2022 John Wiley & Sons Ltd.)

Background: 15-Lipoxygenase 1 (15LO1) is expressed in airway epithelial cells in patients with type 2-high asthma in association with eosinophilia. Chronic rhinosinusitis with nasal polyps (CRSwNP) is also associated with type 2 inflammation and eosinophilia. CCL26/eotaxin 3 has been reported to be regulated by 15LO1 in lower airway epithelial cells. However, its relation to 15LO1 in patients with CRSwNP or mechanisms for its activation are unclear., Objective: We sought to evaluate 15LO1 and CCL26 expression in nasal epithelial cells (NECs) from patients with CRSwNP and healthy control subjects (HCs) and determine whether 15LO1 regulates CCL26 in NECs through extracellular signal-regulated kinase (ERK) activation., Methods: 15LO1, CCL26, and phosphorylated ERK were evaluated in NECs from patients with CRSwNP and HCs. 15LO1/CCL26 and CCL26/cytokeratin 5 were colocalized by means of immunofluorescence. IL-13-stimulated NECs were cultured at an air-liquid interface with or without 15-lipoxygenase 1 gene (ALOX15) Dicer-substrate short interfering RNAs (DsiRNA) transfection, a specific 15LO1 enzymatic inhibitor, and 2 ERK inhibitors. Expression of 15LO1 and CCL26 mRNA and protein was analyzed by using quantitative RT-PCR, Western blotting, and ELISA., Results: 15LO1 expression was increased in nasal polyp (NP) epithelial cells compared with middle turbinate epithelial cells from patients with CRSwNP and HCs. 15LO1 expression correlated with CCL26 expression and colocalized with CCL26 expression in basal cells of the middle turbinate and NPs from patients with CRSwNP. In primary NECs in vitro, IL-13 induced 15LO1 and CCL26 expression. 15LO1 knockdown and inhibition decreased IL-13-induced ERK phosphorylation and CCL26 expression. ERK inhibition (alone) similarly decreased IL-13-induced CCL26. Phosphorylated ERK expression was increased in NECs from CRSwNP subjects and positively correlated with both 15LO1 and CCL26 expression., Conclusions: 15LO1 expression is increased in NP epithelial cells and contributes to CCL26 expression through ERK activation. 15LO1 could be considered a novel therapeutic target for CRSwNP., (Published by Elsevier Inc.)