Perturbated glucose metabolism augments epithelial cell proinflammatory function in chronic rhinosinusitis.

BACKGROUND: Glucose concentrations are increased in nasal secretions in chronic rhinosinusitis (CRS). However, the glucose metabolism and its contribution to disease pathogenesis in CRS remain unexplored. OBJECTIVES: We sought to explore the glucose metabolism and its effect on the function of nasal epithelial cells in CRS with and without nasal polyps (CRSwNP and CRSsNP). METHODS: Glucose metabolites were detected with mass spectrometry. The mRNA levels of glucose transporters (GLUTs), metabolic enzymes, and inflammatory mediators were detected by quantitative RT-PCR. The protein expression of GLUTs was studied by immunofluorescence staining, Western blotting, and flow cytometry. Glucose uptake was measured by using fluorescent glucose analog. Human nasal epithelial cells (HNECs) were cultured. Bioenergetic analysis was performed with Seahorse XF analyzer. Gene expression in HNECs was profiled by RNA sequencing. RESULTS: Increased glucose concentrations in nasal secretions was confirmed in both CRSsNP and CRSwNP. GLUT4, GLUT10, and GLUT11 were abundantly expressed in HNECs, whose expression was upregulated by inflammatory cytokines and D-glucose and was increased in CRS. Glucose uptake, glycolysis and tricarboxylic acid cycle metabolites, metabolic enzymes, and extracellular acidification rate and oxygen consumption rates were increased in HNECs in CRSsNP and CRSwNP, with a predominant shift to glycolysis. HNECs treated with high-level apical D-glucose showed enhanced glucose uptake, predominant glycolysis, and upregulated production of IL-1α, IL-1ß, TNF-α, CCL20, and CXCL8, which was suppressed by 2-deoxy-D-glucose, an inhibitor of glycolysis. CONCLUSIONS: Increased glucose in nasal secretions promotes glucose uptake and predominant glycolysis in epithelial cells, augmenting the proinflammatory function of epithelial cells in CRS.

Untargeted metabolomic profiling identifies disease-specific and outcome-related signatures in chronic rhinosinusitis.

BACKGROUND: Although metabolomics provides novel insights into disease mechanisms and biomarkers, the metabolic alterations in local tissues affected by chronic rhinosinusitis (CRS) are unknown. OBJECTIVE: This study aimed to determine the metabolomic profiles of sinonasal tissues associated with different types of CRS and their treatment outcomes. METHODS: Untargeted metabolomic profiling was performed on sinonasal tissues obtained from patients with eosinophilic CRS with nasal polyps (CRSwNP), noneosinophilic CRSwNP or CRS without nasal polyps (CRSsNP), and controls. The messenger RNA (mRNA) levels of inflammatory cytokines in nasal tissues were detected by quantitative real-time reverse transcriptase PCR. Nasal polyp tissues were cultured ex vivo and treated with glutathione. RESULTS: Distinct metabolomic profiles were observed for the CRS subtypes. Eosinophilic CRSwNP had profoundly enhanced unsaturated fatty acid oxidization, which correlated with mucosal eosinophil numbers and IL-5 mRNA levels. Noneosinophilic CRSwNP was characterized by uric acid accumulation. Increased uric acid levels were positively correlated with mucosal neutrophil numbers and IFN-γ, IL-17A, IL-1ß, and IL-8 mRNA levels. Disrupted purine metabolism was specifically detected in CRSsNP. Reduced levels of amino acid metabolites were found in eosinophilic CRSwNP and CRSsNP, and were inversely associated with mucosal total inflammatory cell numbers and inflammatory cytokines. Compared to non-difficult-to-treat CRS, difficult-to-treat CRS had higher glutathione disulfide levels, which were positively correlated with IL-8 mRNA levels. Glutathione treatment reduced IL-8 mRNA expression in cultured nasal polyp tissues. CONCLUSIONS: Specific metabolic signatures are associated with different types of CRS, inflammatory patterns, and disease outcomes, which may provide novel insights into pathophysiologic mechanisms, subtype-specific biomarkers, and treatment targets of CRS.

Extrafollicular PD-1highCXCR5-CD4+ T cells participate in local immunoglobulin production in nasal polyps.

BACKGROUND: Local immunoglobulin hyperproduction is observed in nasal polyps (NPs) with and without ectopic lymphoid tissues (eLTs). OBJECTIVE: Our aim was to identify the T-cell subsets involved in local immunoglobulin production independent of eLTs in NPs. METHODS: The localization, abundance, and phenotype of CD4+ T-cell subsets were studied by immunofluorescence, flow cytometry, and single-cell RNA sequencing. Purified nasal T-cell subsets were cultured with autologous peripheral naive B cells to explore their function. Programmed death ligand 1 and programmed death ligand 2 expression in NPs was investigated by immunofluorescence staining and flow cytometry. RESULTS: Accumulation of PD-1highCXCR5-CD4+ T cells outside lymphoid aggregates was found in NPs. Nasal PD-1highCXCR5-CD4+ T cells were characterized by a unique phenotype that was related to B-cell help and tissue residency and distinct from PD-1-/intCXCR5- and CXCR5+ CD4+ T cells in NPs as well as PD-1highCXCR5highCD4+ follicular helper T cells in tonsils. Compared with the frequencies of PD-1highCXCR5-CD4+ T cells and their IFN-γ+, IL-17A+, and IL-21+ subsets in the control inferior turbinate tissues, the frequencies of these cells and their subsets were increased in both eosinophilic and noneosinophilic NPs, whereas the frequencies of the IL-4+ and IL-4+IL-21+ subsets were increased only in eosinophilic NPs. Nasal PD-1highCXCR5-CD4+ T cells induced immunoglobulin production from B cells in a potency comparable to that induced by tonsillar follicular helper T cells. PD-1highCXCR5-CD4+ T-cell frequencies were correlated with IgE levels in eosinophilic NPs. PD-L1 and PD-L2 suppressed the function of PD-1highCXCR5-CD4+ T cells, and their levels were reduced in NPs. PD-1highCXCR5-CD4+ T-cell abundance was associated with the postsurgical relapse of NPs. CONCLUSION: PD-1highCXCR5-CD4+ T cells participate in local immunoglobulin production independent of eLTs in NPs.

Inflammatory Endotypes and Tissue Remodeling Features in Antrochoanal Polyps.

PURPOSE: The pathogenic mechanisms of antrochoanal polyps (ACPs) remain largely unknown. This study aimed to characterize inflammatory patterns and tissue remodeling features in ACPs. METHODS: Inflammatory cell infiltration and tissue edema severity as well as fibrin deposition in ACPs and bilateral eosinophilic and noneosinophilic nasal polyps (NPs) were studied with immunohistochemical and immunofluorescence staining. Cytokine levels in sinonasal tissues were detected with the Bio-Plex assay. The expression of coagulation and fibrinolytic markers was measured using reverse-transcription polymerase chain reaction and enzyme-linked immunosorbent assays. RESULTS: Compared to control tissues and bilateral eosinophilic and noneosinophilic NPs, ACPs had higher levels of neutrophil infiltration and expression of myeloperoxidase (MPO), interleukin (IL)-8 and interferon (IFN)-γ. In total, 94.4% of ACPs demonstrated an eosinophil cationic protein/MPO ratio of < 1, compared to 79.0% of noneosinophilic and 26% of eosinophilic NPs. Principle component and multiple correspondence analyses revealed a neutrophilic and type 1 inflammation pattern in ACPs. Compared to control tissues, edema scores and fibrin deposition were increased, whereas d-dimer and tissue plasminogen activator (tPA) levels were decreased in ACPs and bilateral NPs, with more prominent changes in ACPs even than in eosinophilic NPs. The tPA levels were negatively correlated with IFN-γ, IL-8, and MPO levels in ACPs. Neutrophils were the major cellular source of IFN-γ in ACPs, and the number of IFN-γ+ neutrophils was elevated in ACPs than in control tissues and bilateral eosinophilic and noneosinophilic NPs. CONCLUSIONS: ACPs are characterized by the neutrophilic and type 1 inflammation endotype. Neutrophil-derived IFN-γ is associated with reduced tPA production in ACPs.

Cold-inducible RNA-binding protein contributes to tissue remodeling in chronic rhinosinusitis with nasal polyps.

BACKGROUND: Cold-inducible RNA-binding protein (CIRP) is a newly identified damage-associated molecular pattern molecule. Its roles beyond promoting inflammation and in human diseases are poorly understood. This study aimed to investigate the involvement of CIRP in chronic rhinosinusitis with nasal polyps (CRSwNP). METHODS: Immunohistochemistry, quantitative RT-PCR, and ELISA were used to detect the expression of CIRP and matrix metalloproteinases (MMPs) in sinonasal mucosal samples and nasal secretions. Human nasal epithelial cells (HNECs) and THP-1 cells, a human monocytic/macrophage cell line, were cultured to explore the regulation of CIRP expression and MMP expression. RESULTS: Cytoplasmic CIRP expression in nasal epithelial cells and CD68+ macrophages in sinonasal tissues, and CIRP levels in nasal secretions were significantly increased in both patients with eosinophilic and noneosinophilic CRSwNP as compared to those in control subjects. IL-4, IL-13, IL-10, IL-17A, TNF-α, Dermatophagoides pteronyssinus group 1, and lipopolysaccharide induced the production and secretion of CIRP from HNECs and macrophages differentiated from THP-1 cells. CIRP promoted MMP2, MMP7, MMP9, MMP12, and vascular endothelial growth factor A (VEGF-A) production from HNECs, macrophages differentiated from THP-1 cells, and polyp tissues, which was inhibited by the blocking antibody for Toll-like receptor 4, but not advanced glycation end products. The expression of MMPs and VEGF-A in tissues correlated with CIRP levels in nasal secretions in patients with CRSwNP. CONCLUSIONS: The upregulated production and release of CIRP from nasal epithelial cells and macrophages may contribute to the edema formation in both eosinophilic and noneosinophilic CRSwNP by inducing MMP and VEGF-A production from epithelial cells and macrophages.

Stromal cells and B cells orchestrate ectopic lymphoid tissue formation in nasal polyps.

BACKGROUND: Although the importance of ectopic lymphoid tissues (eLTs) in the pathophysiology of nasal polyps (NPs) is increasingly appreciated, the mechanisms underlying their formation remain unclear. OBJECTIVE: To study the role of interleukin (IL)-17A, C-X-C motif chemokine ligand 13 (CXCL13) and lymphotoxin (LT) in eLT formation in NPs. METHODS: The expression levels of CXCL13 and LT and their receptors, in addition to the phenotypes of stromal cells in NPs, were studied by flow cytometry, immunostaining, and real-time reverse transcription-polymerase chain reaction (RT-PCR). Purified nasal stromal cells and B cells were cultured, and a murine model of nasal type 17 inflammation was established by intranasal curdlan challenge for the mechanistic study. RESULTS: The excessive CXCL13 production in NPs correlated with enhanced IL-17A expression. Stromal cells, with CD31- Pdpn+ fibroblastic reticular cell (FRC) expansion, were the major source of CXCL13 in NPs without eLTs. IL-17A induced FRC expansion and CXCL13 production in nasal stromal cells. In contrast, B cells were the main source of CXCL13 and LTα1 ß2 in NPs with eLTs. CXCL13 upregulated LTα1 ß2 expression on B cells, which in turn promoted CXCL13 production in nasal B cells and stromal cells. LTα1 ß2 induced expansion of FRCs and CD31+ Pdpn+ lymphoid endothelial cells, which were the predominant stromal cell types in NPs with eLTs. IL-17A knockout and CXCL13 and LTßR blockage diminished nasal eLT formation in the murine model. CONCLUSION: We identified an important role of IL-17A-induced stromal cell remodeling in the initiation and crosstalk between B and stromal cells via CXCL13 and LTα1 ß2 in the enlargement of eLTs in NPs.

Roles of follicular helper and regulatory T cells in allergic diseases and allergen immunotherapy.

Allergic diseases are characterized by overactive type 2 immune responses to allergens and immunoglobulin E (IgE)-mediated hypersensitivity. Emerging evidence suggests that follicular helper T (TFH ) cells, rather than type 2 T-helper (TH 2) cells, play a crucial role in controlling IgE production. However, follicular regulatory T (TFR ) cells, a specialized subset of regulatory T (TREG ) cells resident in B-cell follicles, restricts TFH cell-mediated help in extrafollicular antibody production, germinal center (GC) formation, immunoglobulin affinity maturation, and long-lived, high-affinity plasma and memory B-cell differentiation. In mouse models of allergic asthma and food allergy, CXCR5+ TFH cells, not CXCR5- conventional TH 2 cells, are needed to support IgE production, otherwise exacerbated by CXCR5+ TFR cell deletion. Upregulation of TFH cell activities, including a skewing toward type 2 TFH (TFH 2) and IL-13 producing TFH (TFH 13) phenotypes, and defects in TFR cells have been identified in patients with allergic diseases. Allergen immunotherapy (AIT) reinstates the balance between TFH and TFR cells in patients with allergic diseases, resulting in clinical benefits. Collectively, further understanding of TFH and TFR cells and their role in the immunopathogenesis of allergic diseases creates opportunities to develop novel therapeutic approaches.

CD23 expression on switched memory B cells bridges T-B cell interaction in allergic rhinitis.

BACKGROUND: The contribution of B-cell subsets and T-B cell interaction to the pathogenesis of allergic rhinitis (AR) and mechanisms of allergen immunotherapy (AIT) remain poorly understood. This study aimed to outline circulating B-cell signature, the underlying mechanism, and its association with clinical response to AIT in patients with AR. METHODS: IgD/CD27 and CD24/CD38 core gating systems were used to determine frequencies and phenotypes of B cells. Correlations between B cells, T cells, antigen-specific IgE, and disease severity in AR patients were investigated. Switched memory B cells were co-cultured with type 2 follicular helper T (Tfh2) cells and follicular regulatory T (Tfr) cells. Associations between B-cell subsets and clinical benefits of AIT were analyzed. RESULTS: Frequencies and absolute numbers of circulating memory B cells were increased in AR patients. CD23 expression on CD19+ CD20+ CD27+ IgD- switched memory B cells was significantly enhanced and positively correlated with antigen-specific IgE levels, symptom scores, and Tfh2/Tfr cell ratio in AR patients. Compared with those from healthy controls, Tfh2 cells from AR patients had a greater capacity to induce CD23 expression on switched memory B cells via IL-4, which was unable to be sufficiently suppressed by AR-associated Tfr cells with defective IL-10 expression. CD23 expression on switched memory B cells was downregulated after 12-month AIT, which positively associated with disease remission in AR patients. CONCLUSION: T-B cell interaction, bridged by CD23 expression particularly on switched memory B cells, may be involved in the disease pathogenesis and mechanism of AIT in patients with AR.

The IL-37-Mex3B-Toll-like receptor 3 axis in epithelial cells in patients with eosinophilic chronic rhinosinusitis with nasal polyps.

BACKGROUND: The role of IL-37, an immunosuppressive cytokine, in patients with inflammatory diseases is unclear. OBJECTIVE: We sought to explore the expression and pathogenic function of IL-37 in patients with chronic rhinosinusitis (CRS). METHODS: Expression levels of IL-37, IL-18 receptor α, IL-1 receptor 8, Mex3 RNA binding family member B (Mex3B), and thymic stromal lymphopoietin (TSLP) in nasal samples were studied by using quantitative RT-PCR, immunohistochemistry, Western blotting, and ELISA. Human nasal epithelial cells (HNECs) and the BEAS-2B cell line were stimulated with various cytokines and Toll-like receptor (TLR) agonists. In some experiments BEAS-2B cells were transfected with Mex3B small interfering RNA or overexpressing lentiviruses. Genes regulated by IL-37b in HNECs were studied by using RNA sequencing analysis. IL-37b function was confirmed in mice in vivo. RESULTS: Compared with control subjects, although mRNA and protein expression of IL-37 were upregulated in diseased tissues, especially in nasal epithelial cells, in patients with CRS without nasal polyps or in patients with chronic rhinosinusitis with nasal polyps (CRSwNP), IL-37 levels in nasal secretions were reduced in patients with eosinophilic CRSwNP. Type 2 cytokines inhibited IL-37 secretion from HNECs. HNECs expressed IL-37 receptors, IL-18 receptor α, and IL-1 receptor 8. IL-37b downregulated the expression of Mex3B, a TLR3 coreceptor, in HNECs. IL-37b suppressed polyinosinic-polycytidylic acid-induced TSLP production in HNECs in vitro and in murine nasal epithelial cells in vivo. Knocking down or overexpressing Mex3B in BEAS-2B cells abolished the inhibitory effect of IL-37b. Secreted IL-37 levels negatively correlated with Mex3B and TSLP levels and eosinophil numbers in patients with eosinophilic CRSwNP. CONCLUSIONS: The suppressed IL-37 secretion caused by a type 2 milieu can enhance Mex3B-mediated TLR3 activation and subsequent TSLP production in nasal epithelial cells and therefore promotes eosinophilic inflammation in patients with CRSwNP.

Hemokinin-1 stimulates C-C motif chemokine ligand 24 production in macrophages to enhance eosinophilic inflammation in nasal polyps.

BACKGROUND: The mechanisms underlying mucosal eosinophilia in chronic rhinosinusitis with nasal polyps (CRSwNP) remain poorly clarified. The nervous system and neuropeptides play an important role in the regulation of immune response. Herein we explore the expression and function of hemokinin-1 (HK-1), a newly identified tachykinin, along with its receptor neurokinin 1 receptor (NK1R) in CRSwNP. METHODS: HK-1, NK1R, and C-C motif chemokine ligand 24 (CCL24) expression in nasal tissues (53 eosinophilic CRSwNP, 32 non-eosinophilic CRSwNP, and 33 controls) was investigated by quantitative reverse transcript polymerase chain reaction (RT-PCR) and immunofluorescence staining. THP-1, a human monocytic leukemia cell line, and eosinophilic polyp tissues were stimulated with HK-1. Cells, tissues, and culture supernatants were subsequently collected for detection of the production of various inflammatory cytokines and chemokines by quantitative RT-PCR and enzyme-linked immunoassay. RESULTS: HK-1 and NK1R mRNA and protein expression were upregulated in eosinophilic and non-eosinophilic nasal polyps compared with control tissues, with eosinophilic polyps demonstrating a higher upregulation compared with that of non-eosinophilic polyps. Eosinophils constituted the major source of HK-1, whereas macrophages were the predominant cell type exhibiting NK1R in eosinophilic polyps. HK-1 induced CCL24 production from macrophages differentiated from THP-1 cells; this was abolished by an NK1R antagonist. HK-1 also induced CCL24 production from ex vivo-cultured eosinophilic nasal polyps. CCL24 was expressed by macrophages in eosinophilic but not non-eosinophilic polyps. The expression level of HK-1 correlated with CCL24 expression and tissue eosinophilia in eosinophilic nasal polyps. CONCLUSION: Eosinophil-derived HK-1 induces CCL24 production from macrophages and therefore exaggerates eosinophilic inflammation in CRSwNP.

Allergen immunotherapy improves defective follicular regulatory T cells in patients with allergic rhinitis.

BACKGROUND: The function of follicular regulatory T (TFR) cells, especially in regulating IgE production in patients with allergic diseases, is poorly understood. OBJECTIVE: We sought to investigate the phenotype, function, and clinical relevance of TFR cells in patients with allergic rhinitis (AR). METHODS: The phenotype and frequency of tonsillar and circulating TFR cells were characterized by using flow cytometry. TFR cell function was examined in an assay by coculturing with follicular helper T cells and B cells. The associations between TFR cells and the clinical features in patients with AR before and after allergen immunotherapy (AIT) were analyzed. RESULTS: TFR cells were detected in germinal centers of tonsils, but compared with subjects without AR, the frequencies decreased in patients with AR who were allergic to house dust mites. Circulating TFR cells in blood were phenotypically and numerically correlated with tonsillar TFR cells, and a reduction of circulating TFR cells but not total or CXCR5- regulatory T cells was noted in patients with AR compared with healthy control subjects. Moreover, circulating TFR cells in patients with AR showed a specific defect in suppressing IgE production but were capable of suppressing production of other immunoglobulin types. We identified negative associations of circulating TFR cell frequencies and function with antigen-specific IgE levels or disease severity in patients with AR. After AIT, the frequencies and function of circulating TFR cells were improved, which positively associated with disease remission. CONCLUSION: Impairment in TFR cells might contribute to aberrant IgE production in patients with AR, and AIT improves defective TFR cell function. TFR cells might serve as a potential biomarker to monitor clinical response to AIT.

Deficiency in interleukin-10 production by M2 macrophages in eosinophilic chronic rhinosinusitis with nasal polyps.

BACKGROUND: M2 macrophages are characterized by high interleukin-10 (IL-10) expression and are critical for resolving inflammation. Although increased accumulation of M2 macrophages has been demonstrated in chronic rhinosinusitis with nasal polyps (CRSwNP), particularly the eosinophilic type, their functional relevance in CRSwNP remains poorly understood. METHODS: M1 and M2 macrophages and IL-10 expression in sinonasal tissues were detected by double-immunofluorescence staining. THP-1 cells, a human monocytic leukemia cell line, were stimulated with various cytokines to study macrophage polarization and IL-10 expression. Polyp size, computed tomography (CT) scans, and symptom severity were scored. RESULTS: Compared with numbers in control tissues, the numbers of total CD68+ macrophages, interferon regulatory factor 5-positive and CD68+ M1 macrophages, and CD163+ CD68+ and CD206+ CD68+ M2 macrophages were increased in both eosinophilic and non-eosinophilic polyps. However, compared with non-eosinophilic polyps, eosinophilic polyps contained fewer M1 macrophages and more M2 macrophages. Consistent with this, the M1/M2 macrophage ratio was increased in non-eosinophilic polyps, whereas it decreased in eosinophilic polyps. Strikingly, the numbers of IL-10+ CD68+ macrophages and the percentage of IL-10+ CD68+ macrophages relative to the total number of macrophages were decreased in eosinophilic polyps, despite the upregulation of M2 macrophages in this type of polyp. The number of IL-10+ CD68+ M2 macrophages correlated negatively with total symptoms scores, polyp sizes, total CT scores, and the total number of inflammatory cells in patients with eosinophilic CRSwNP. Poly I:C downregulated IL-10 expression in M2 macrophages differentiated from THP-1 cells in vitro. CONCLUSION: Impaired IL-10 production by M2 macrophages may contribute to sustained inflammation in eosinophilic CRSwNP.vv.

Increased expression of TIPE2 in alternatively activated macrophages is associated with eosinophilic inflammation and disease severity in chronic rhinosinusitis with nasal polyps.

BACKGROUND: Chronic rhinosinusitis with nasal polyps (CRSwNP) is a multifactorial disorder characterized by exaggerated local immune responses. Tumor necrosis factor-α-induced protein 8-like 2 (TIPE2) is a novel protein with potential immune modulating function. The expression and function of TIPE2 in human airway diseases are unclear. METHODS: The expression of TIPE2 in sinonasal mucosal samples was assessed by means of quantitative reverse transcript-polymerse chain reaction, immunohistochemistry, and Western blotting. The human monocytic/macrophage cell line, THP-1 cells, was stimulated with various cytokines. Computed tomography (CT) scan images, endoscopic findings, and symptoms were scored. RESULTS: Compared with non-eosinophilic polyps and control mucosa, the mRNA and protein expression of TIPE2 was significantly upregulated in eosinophilic polyps, with a further increase in those with asthma. The number of CD68+ CD163+ alternatively activated (M2) macrophages was increased in eosinophilic polyps. TIPE2 was mainly expressed by M2 macrophages in sinonasal mucosa and its expression was upregulated in M2 macrophages in eosinophilic polyps. Interleukin (IL)-4 and IL-13, but not interferon (IFN)-γ or IL-17A, induced TIPE2 expression in differentiated THP-1 cells. The mRNA levels of IL-4 and IL-13 correlated with the mRNA levels of TIPE2 and M2 macrophage markers in sinonasal mucosa. Importantly, the number of TIPE2+ cells, particularly TIPE2+ CD163+ CD68+ M2 macrophages, correlated positively with the number of eosinophils and total inflammatory cells in sinonasal mucosa, as well as disease duration, CT scores, hyposmia scores, and polyp size in CRSwNP. CONCLUSION: The T-helper 2 milieu is able to induce TIPE2 expression in macrophages. TIPE2-positive M2 macrophages potentially contribute to eosinophilic inflammation and disease progression in CRSwNP.