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Background: 17,18-Epoxyeicosatetraenoic acid (17,18-EpETE), an eicosapentaenoic acid metabolite, is generated from dietary oil in the gut, and antiinflammatory activity of 17,18-EpETE was recently reported. Objective: To evaluate the inhibitory effects of 17,18-EpETE in airway inflammation, we examined in vitro and in vivo effects on mucus production, neutrophil infiltration, and cytokine/chemokine production in airway epithelium. Methods: Nasal tissue localization of G protein-coupled receptor 40 (GPR40), a receptor of 17,18-EpETE, was determined by immunohistochemical staining. Expression of GPR40 mRNA in nasal mucosa of chronic rhinosinusitis (CRS) patients and control subjects was determined by reverse transcription-polymerase chain reaction (RT-PCR). The in vitro effects on airway epithelial cells were examined using normal human bronchial epithelial cells and NCI-H292 cells. To examine the in vivo effects of 17,18-EpETE on airway inflammation, we induced goblet cell metaplasia, mucus production, and neutrophil infiltration in mouse nasal epithelium by intranasal lipopolysaccharide (LPS) instillation. Results: GPR40 is mainly expressed in human nasal epithelial cells and submucosal gland cells. RT-PCR analysis revealed that the expression of GPR40 mRNA was increased in nasal tissues from CRS patients compared with those from control subjects. 17,18-EpETE significantly inhibited tumor necrosis factor (TNF)-α-induced production of interleukin (IL)-6, IL-8, and mucin from cultured human airway epithelial cells dose dependently, and these antiinflammatory effects on cytokine production were abolished by GW1100, a selective GPR40 antagonist. Intraperitoneal injection or intranasal instillation of 17,18-EpETE significantly attenuated LPS-induced mucus production and neutrophil infiltration in mouse nasal epithelium. Inflammatory cytokine/chemokine production in lung tissues and bronchoalveolar lavage fluids was also inhibited. Conclusion: These results indicate that 17,18-EpETE plays a regulatory role in mucus hypersecretion and neutrophil infiltration in nasal inflammation. Local or systemic administration may provide a new therapeutic approach for the treatment of intractable airway disease such as CRS. [ABSTRACT FROM AUTHOR]

Background: Nasal epithelial cells and infiltrating eosinophils express tissue factor, and high thrombin activity and excess fibrin deposition are found in nasal secretion and in nasal polyp from patients with chronic rhinosinusitis with nasal polyp (CRSwNP). Activated coagulation factors play important roles not only in thrombosis but also in inflammation through interaction with protease-activated receptors (PAR). However, little is known about the effects of activated coagulation factors on the release of cytokines and extracellular matrix from nasal polyp fibroblasts (NPF). Purpose: The purpose of this study was to analyze the expression of PARs, which are receptors for activated coagulation factors, on NPFs and to determine the roles of thrombin and activated coagulation factor X (FXa) in the release of cytokines and fibronectin from NPFs. Methods: NPFs were obtained from patients with CRSwNP, and the messenger RNA (mRNA) and protein expression of PARs in these NPFs were examined. We then investigated whether thrombin or FXa stimulates the release of transforming growth factor (TGF) beta 1, fibronectin, eotaxin-1, interleukin (IL) 6, or IL-8 from cultured NPFs. The effects of PAR agonists on the release of cytokines and fibronectin were also examined. Results: NPFs expressed the mRNA and proteins of all four PARs: PAR-1, PAR-2, PAR-3, and PAR-4. Both thrombin and FXa significantly stimulated the release of TGF beta 1, fibronectin, eotaxin-1, IL-6, and IL-8 from cultured NPFs. PAR-1 and PAR-2 agonists stimulated the secretion of TGF beta 1, fibronectin, eotaxin-1, IL-6, and IL-8. PAR-3 agonist stimulated the release of TGF beta 1, fibronectin, and eotaxin-1. PAR-4 agonist did not induce the release of these molecules. Conclusion: NPFs play important roles in the pathophysiology of CRSwNP such as in nasal polyp formation and inflammatory cell infiltration by releasing cytokines and extracellular matrix proteins. Activated coagulation factors, thrombin and FXa, stimulate the release of these cytokines and fibronectin from NPFs via PARs. [ABSTRACT FROM AUTHOR]

Background: Alarmins play important roles in the pathogenesis of inflammatory and autoimmune diseases. However, the role of the alarmin protein high-mobility group box 1 (HMGB1) in upper airway inflammation is unclear. Objective: To determine if HMGB1 is present in the nasal mucosa and, if so, to elucidate its role in upper airway inflammation. Methods: Nasal secretions were collected from a total of 32 patients with chronic rhinosinusitis with nasal polyp, allergic rhinitis, and control subjects. The concentration of HMGB1 in nasal secretions and its tissue and cellular localization were examined by enzyme immunoassays and immunofluorescent staining of nasal polyps and cultured nasal epithelial cells. We then examined whether nasal epithelial cells secrete HMGB1 after inflammatory stimulation by tumor necrosis factor (TNF) α. The effects of HMGB1 on the production and secretion of interleukin (IL) 6 and IL-8 were also examined in cultured nasal epithelial cells. Results: Significantly higher concentrations of HMGB1 were found in nasal secretions from patients with chronic rhinosinusitis with nasal polyp or allergic rhinitis compared with the control subjects. HMGB1 expression was localized in the nuclei of epithelial cells and other constitutive cells in nasal polyps and in the nuclei of cultured nasal epithelial cells. TNF-α stimulated the production and secretion of HMGB1 by cultured nasal epithelial cells. HMGB1 stimulated the production and secretion of IL-6 and IL-8 by cultured nasal epithelial cells, and anti-toll-like receptor 4 blocking antibody significantly inhibited HMGB1-induced secretion of IL-6 and IL-8. Conclusions: Nasal secretions contain substantial amounts of HMGB1. TNF-α stimulates the production of HMGB1, which, in turn, upregulates the production and secretion of IL-6 and IL-8 by nasal epithelial cells via toll-like receptor 4, which indicated that HMGB1 plays an important role in the pathogenesis of upper airway inflammation. [ABSTRACT FROM AUTHOR]

Background: Mucus hypersecretion and neutrophil infiltration are important characteristics of airway inflammation. Epidermal growth factor receptor (EGFR) transactivation induces mucus and inflammatory cytokine secretion from airway epithelial cells. To elucidate the roles of EGFR in airway inflammation, the in vitro effects on mucin production and interleukin (IL) 8 secretion from cultured airway epithelial cells and the in vivo effects on mucus hypersecretion and neutrophil infiltration in rat nasal mucosa of the EGFR tyrosine kinase inhibitor AG1478 were examined. Methods: The in vitro effects of AG1478 treatment of cultured NCI-H292 cells on lipopolysaccharide (LPS) induced or tumor necrosis factor (TNF) α induced MUC5AC mucin and IL-8 secretion were evaluated. Hypertrophic and metaplastic changes of goblet cells, mucus production and neutrophil infiltration in rat nasal epithelium were induced by intranasal instillation of LPS in vivo, and the inhibitory effects of AG1478 by intraperitoneal injection or intranasal instillation were examined. Results: AG1478 (1-1000 nM) significantly inhibited both LPS-induced and TNF-α-induced secretion of MUC5AC and IL-8 from cultured NCI-H292 cells in a dose-dependent manner. The expression of MUC5AC and IL-8 messenger RNAs was also significantly inhibited. Intranasal instillation of AG1478 one hour after intranasal LPS instillation significantly inhibited LPS-induced goblet cell metaplasia, mucus production, and neutrophil infiltration in rat nasal epithelium, as did intraperitoneal injection of AG1478 one hour before LPS instillation. Conclusions: These results indicated that EGFR transactivation plays an important role in mucin and IL-8 secretion from airway epithelial cells. Intranasal instillation of an EGFR tyrosine kinase inhibitor may be a new therapeutic approach for the treatment of upper airway inflammation. [ABSTRACT FROM AUTHOR]

Background: Activation of the coagulation system with an increase in thrombin generation is involved in the pathogenesis of tissue remodeling in chronic rhinosinusitis (CRS). Tissue factor (TF) is an important protein for initiation of the extrinsic coagulation pathway, and TF pathway inhibitor (TFPI) is a regulator of TF-induced coagulation. This study was conducted to elucidate the roles of TF and TFPI in the pathogenesis of CRS. Methods: Tissue localization of TF, TFPI, and fibrin was determined by immunostaining of nasal polyps and inferior turbinates obtained during endonasal surgery in patients with CRS with nasal polyp (CRSwNP). Nasal secretions were collected from patients with CRSwNP, allergic rhinitis, and from control patients. The concentrations of TF and TFPI were measured in nasal secretions from each group. The concentrations of TF and TFPI released into culture medium by normal human nasal epithelial cells treated with thrombin, protease-activated receptor 1 agonist peptide, or tumor necrosis factor α were also measured. Results: TF expression was localized in nasal epithelial cells and in infiltrating eosinophils of nasal mucosa. TFPI expression was localized in nasal epithelial cells, and fibrin deposition was observed in nasal secretions and the lamina propria of nasal polyps. Nasal secretions contained significant concentrations of TF and TFPI. The concentration of TFPI in nasal secretions correlated positively with thrombin activity and the concentration of thrombin-antithrombin III complex. Treatment with thrombin, protease-activated receptor 1 agonist peptide, or tumor necrosis factor α stimulated significant release of TF and TFPI from cultured nasal epithelial cells. Conclusions: By upregulating the coagulation system, TF and TFPI play an important role in the pathogenesis of CRSwNP. [ABSTRACT FROM AUTHOR]

Background: Predominant eosinophil infiltration and tissue remodeling are common characteristics of chronic airway inflammation such as nasal polyposis and bronchial asthma. This study was designed to elucidate the role of eosinophils in tissue remodeling of chronic airway inflammation; eosinophil-epithelial interactions were examined by the coculture of airway epithelial cell line NCI-H292 with the eosinophilic cell line EoL-1 or with human blood eosinophils. Methods: The coculture-induced production of MUC5AC mucin, platelet-derived growth factor AB (PDGF-AB), vascular endothelial growth factor (VEGF), transforming growth factor (TGF) beta1, and interleukin-8 (IL-8) were evaluated by enzyme-linked immunosorbent assay and reverse transcription-polymerase chain reaction. Results: Eosinophil-epithelial interactions significantly stimulated the secretion of MUC5AC, PDGF-AB, VEGF, TGF-beta1, and IL-8 in culture supernatants. The epidermal growth factor receptor tyrosine kinase inhibitor AG1478 inhibited the coculture-induced secretion of MUC5AC, PDGF-AB, VEGF, and IL-8. Neutralizing antibodies directed against TGF-alpha or amphiregulin and pan-metalloproteinase inhibitor GM6001 inhibited the coculture-induced secretion of MUC5AC and amphiregulin from the cocultured NCI-H292 cells. Coculture of NCI-H292 cells with peripheral blood eosinophils also significantly stimulated MUC5AC production. Conclusion: The results of this study indicate that eosinophil-epithelial cell interactions are important in the pathogenesis of tissue remodeling of eosinophil-predominant airway inflammation such as occurs in nasal polyposis and bronchial asthma. [ABSTRACT FROM AUTHOR]

Background: Recent experiments have revealed that valproic acid (VPA), a histone deacetylase inhibitor, has neuroregenerative effects in rodent models of spinal cord and optic nerve injury. VPA has a potential to provide a new therapeutic strategy for sensorineural olfactory dysfunction. To elucidate the effects of VPA on regeneration of olfactory sensory neurons, we examined the in vivo effects of oral VPA administration on recovery from methimazole-induced degeneration of olfactory neuroepithelium in mice. Methods: Male ICR mice (10 weeks old) were intraperitoneally injected with methimazole (75 mg/kg), an olfactory toxic reagent, to induce degenerative changes in the olfactory neuroepithelium. The effects of daily VPA administration on recovery from methimazole-induced changes were examined histologically. Results: Oral VPA administration dose dependently enhanced increases in epithelial thickness and number of olfactory marker protein (OMP) positive cells in the olfactory epithelium during recovery from methimazole-induced degeneration. VPA also enhanced early increases in the number of Ki-67+ and growth-associated protein-43+ cells during the regeneration of olfactory neuroepithelium. Conclusion: VPA administration promotes regeneration of olfactory sensory neurons in damaged neuroepithelium by stimulating the proliferation and differentiation of olfactory precursor cells. VPA has been used for several decades to safely treat neurological disorders. VPA may provide a new therapeutic strategy for the treatment of olfactory dysfunction caused by degeneration of the olfactory neuroepithelium. [ABSTRACT FROM AUTHOR]

Background: Heparin is one of the most important anticoagulant drugs. It has been known that heparin also possesses anti-inflammatory activities. Mucus hypersecretion is an important characteristic of airway inflammation. However, little is known about the regulatory effects of heparin on mucus hypersecretion in airway epithelial cells. To elucidate the anti-inflammatory function of heparin in airway epithelial cells, we examined the in vivo effects of heparin on mucus hypersecretion and neutrophil infiltration in rat nasal epithelium. We also examined the in vitro effects of heparin on mucin production and IL-8 secretion from cultured human airway epithelial cells. Methods: We induced hypertrophic and metaplastic changes of goblet cells in rat nasal epithelium by intranasal lipopolysaccharide (LPS) instillation. The effects of intranasal instillation with heparin on mucus production and neutrophil infiltration were examined. in vitro effects of heparin on airway epithelial cells were examined using cultured NCI-H292 cells. Mucus secretion was evaluated by enzyme-linked immunosorbent assay using an anti-MUC5AC monoclonal antibody. Results: Intranasal instillation with unfractionated heparin (UFH; 100 IU/0.1 mL) or low molecular weight heparin (LMWH; 100 IU/0.1 mL) at 30 minutes before LPS instillation significantly inhibited LPS-induced mucus production and neutrophil infiltration in rat nasal epithelium. UFH or LMWH inhibited tumor necrosis factor alpha (10 ng/mL)-induced secretion of MUC5AC and IL-8 from NCI-H292 cells in a dose-dependent manner (0.01-10 IU/mL). MUC5AC mRNA expression was also significantly inhibited. Conclusion: These results indicate that heparin inhibits airway mucus hypersecretion in airway epithelial cells directly and indirectly through the suppression of IL-8 secretion and neutrophil infiltration. [ABSTRACT FROM AUTHOR]

Background: Thrombin, the effector enzyme of the coagulation system, has been reported to promote inflammatory responses in nasal diseases through its protease-activated receptors (PARs). Chronic rhinosinusitis (CRS) is characterized by increased deposition of extracellular matrix proteins, tissue remodeling, and formation of nasal polyps. The role of thrombin in chronic nasal inflammation-associated tissue remodeling still has not been appraised. This study was conducted to elucidate the role of thrombin in the pathogenesis of CRS. Methods: Nasal secretion was collected from patients with CRS with nasal polyp (CRSwNP) with asthma (n = 9), CRSwNP without asthma (n = 10), allergic rhinitis (n = 7), and control patients (n = 3). The concentrations of thrombin, thrombin-antithrombin (TAT) complex, and vascular endothelial growth factor (VEGF) were evaluated by enzyme immunoassays. The concentration of thrombin and TAT complex was measured in nasal secretion from each group of patients, and VEGF was measured in culture medium from airway epithelial cells treated with thrombin or thrombin receptor agonist peptide. Results: Thrombin and TAT complex were significantly increased in nasal secretion of patients with CRSwNPs with asthma compared with the control group. Thrombin and PAR-1 agonist peptide significantly stimulated VEGF secretion from cultured human airway epithelial cells. Conclusion: The results of this study showed that there is increased activation of the coagulation system in the nasal mucosa of CRS patients and that thrombin may play a role in nasal polyp formation by stimulating VEGF production from airway epithelial cells. [ABSTRACT FROM AUTHOR]

Objectives: Prostaglandin (PG) E2 is a potential anti-inflammatory mediator that attenuates airway inflammation. To elucidate the functions of the PGE2 receptors (EP1, EP2, EP3, and EP4) in allergic inflammation, we examined the in vivo effects of EP agonists on mucus hypersecretion and eosinophil infiltration in rat nasal epithelium. Methods: We induced hypertrophic and metaplastic changes in goblet cells in nasal epithelium of ovalbumin-sensitized rats by intranasal challenge with ovalbumin. The effects of subcutaneous injections of EP agonists on mucus production and eosinophil infiltration were examined. Results: The EP4 agonist (1 to 100 μg/kg) dose-dependently inhibited ovalbumin-induced mucus production. The EP2 and EP3 agonists (100 μg/kg) also significantly inhibited mucus production. The EP3 agonist inhibited antigen-induced eosinophil infiltration, whereas the EP1 agonist showed no effect. This suppression of mucus production by the EP4 agonist was only effective when the EP4 agonist was given in the effector phase; administration in the induction phase resulted in no effect. Conclusions: These results indicate that PGE2 acts as an anti-inflammatory mediator via the EP receptors of airways in allergic inflammation. Selective EP agonists may provide a new therapeutic strategy for airway mucus hypersecretion. [ABSTRACT FROM AUTHOR]

Objectives: Th2 cytokines such as interleukin (IL) 4 and IL-13 are potential mediators for mucus hypersecretion in allergic inflammation. To elucidate the functions of Th2 cytokines in allergic rhinitis, we examined the in vivo effects of the Th2 cytokine inhibitor suplatast tosilate on mucus hypersecretion and eosinophil infiltration in rat nasal epithelium. Methods: We induced hypertrophic and metaplastic changes in goblet cells in the nasal epithelium of ovalbumin-sensitized rats by intranasal challenge with ovalbumin. The effects of orally administered suplatast tosilate on mucus production and eosinophil infiltration were examined. Results: Suplatast tosilate (30 and 100 mg/kg) dose-dependently inhibited ovalbumin-induced mucus production and eosinophil infiltration. These suppressions of mucus production and eosinophil infiltration were only effective when suplatast tosilate was given in the effector phase; administration in the induction phase resulted in no effect. Conclusions: These results indicate that Th2 cytokines are important mediators of mucus hypersecretion and eosinophil infiltration in allergic rhinitis. Suplatast tosilate may be useful for the treatment of allergic rhinitis by attenuating the inflammation of the effector phase. [ABSTRACT FROM AUTHOR]

Objectives: We examined the in vivo effects of agonists for prostaglandin E2 receptors (EP1, EP2, EP3, and EP4) on mucus hypersecretion. We also examined the in vitro effects of EP agonists on airway epithelial cells. Methods: For the in vivo study, we induced hypertrophic and metaplastic changes of goblet cells in rat nasal epithelium by intranasal lipopolysaccharide (LPS) instillation. For the in vitro study, we used NCI-H292 cells and cultured human nasal epithelial cells. Results: Subcutaneous injection of the EP4 agonist (1 to 100 μg/kg) dose-dependently inhibited LPS-induced mucus production and neutrophil infiltration. The EP3 agonist (100 μg/kg) also had some inhibitory effects on mucus production, whereas the EP1 and EP2 agonists showed no effect. The LPS-induced mucus secretion was significantly inhibited by the EP3 and EP4 agonists at 10-6 mol/L in cultured epithelial cells. The LPS-induced interleukin-8 secretion was also inhibited by the EP3 and EP4 agonists. Conclusions: These results indicate that the EP4 agonist inhibited LPS-induced airway mucus hypersecretion directly or indirectly through the suppression of interleukin-8 secretion and neutrophil infiltration. [ABSTRACT FROM AUTHOR]