Expression of adhesion molecules in cultured human nasal mucosal microvascular endothelial cells activated by interleukin-1 beta or tumor necrosis factor-alpha: effects of dexamethasone

Mechanisms and clinical implications of glucocorticosteroids in the treatment of allergic rhinitis

Allergic rhinitis is a common airway disease characterized by hypersensitivity, exudation, hypersecretion, inflammatory cell infiltration and remodelling. Intranasal glucocorticosteroids are the most effective drugs for controlling the inflammation caused by allergic rhinitis. Glucocorticosteroids exert anti-inflammatory effects through at least two pathways: the transactivation pathway and the transrepression pathway. Glucocorticosteroids also exert regulatory functions by inducing regulatory cytokines and forkhead box P3 (FoxP3(+)) regulatory T cells. Evidence suggests that intranasal glucocorticosteroids control not only nasal symptoms but also ocular symptoms. In contrast to sedating H1 receptor antagonists, intranasal glucocorticosteroids can improve impaired performance symptoms, such as daytime sleepiness, associated with allergic rhinitis. Recent studies suggest that intranasal glucocorticosteroids might also be useful for the prophylactic treatment of pollinosis; this possibility is supported by the molecular mechanism of the anti-inflammatory action of glucocorticosteroids. These findings suggest that intranasal glucocorticosteroids might be positioned as first-line drugs for the treatment of both perennial and seasonal allergic rhinitis.

Heterogeneity of human nasal vascular and sinusoidal endothelial cells from the inferior turbinate

The vast heterogeneity of endothelial cells (EC) in various organs necessitates isolation of EC from the relevant organs when defining mechanisms of site-specific pathologies. We report a novel finding that describes the presence of two heterogeneous populations of human nasal microvascular EC isolated from the inferior turbinate. Light and electron microscopy, flow cytometric analysis, and immunocytochemistry analysis demonstrated that one EC population exhibited the classic vascular endothelial markers with cobblestone-like morphology, whereas the other was sinusoidal with fusiform morphology. The sinusoidal EC (SEC) lacked surface expression of the endothelial markers CD31 and E-selectin, were discontinuous, showed fenestrae and pinocytic vesicles, and did not form tight junctions. Gene expression analysis using microarray revealed significant but limited heterogeneity between the two cell types. Immunohistochemical staining of normal nasal biopsies confirmed the presence of two distinct populations of EC. We found that CD31 was exclusively expressed on vascular EC (VEC), whereas the molecule L-SIGN was mainly expressed on SEC. Both cell types formed capillary-like tubules in matrigel in vitro. The two heterogeneous EC populations provide a unique in vitro system to study the biology of nasal VEC and SEC in normal conditions and in inflammatory processes in various nasal disorders.

HLA-DR and ICAM-1 expression and modulation in epithelial cells from nasal polyps

OBJECTIVE/HYPOTHESIS

Through human leukocyte antigen-DR (HLA-DR) and intercellular adhesion molecule-1 (ICAM-1) expression, nasal epithelial cells could actively participate in the chronic inflammation and eosinophil infiltration observed in nasal polyps. The objective of the study was to evaluate HLA-DR and ICAM-1 expression in polyp epithelium and in a culture model of polyp epithelial cells allowing ciliated and secretory differentiation.

STUDY DESIGN

Prospective non-randomized controlled in vitro study.

METHODS

The in vitro HLA-DR and ICAM-1 expression was studied under basal conditions or after exposure to interferon-gamma, transforming growth factor-beta1, lipopolysaccharide, dexamethasone, or cetirizine. HLA-DR and ICAM-1 expression was investigated in situ by immunohistochemical staining of polyps and in vitro by immunofluorescent staining of cell cultures. HLA-DR and ICAM-1 were localized in cultured cells by confocal microscopy. Cultured cells expressing HLA-DR and ICAM-1 were quantified by flow cytometry.

RESULTS

Both HLA-DR and ICAM-1 showed significant immunostaining of nasal polyp epithelium. In nasal polyp epithelial cell cultures, less than 5% of cells were positive for HLA-DR whereas 40% were positive for ICAM-1 at day 3. In vitro, HLA-DR was mainly located in the cytoplasm and ICAM-1 predominated on the apicolateral cytoplasmic membrane. Comparison of in situ and in vitro results showed that well-differentiated and poorly differentiated cells predominantly expressed HLA-DR and ICAM-1, respectively. Interferon-gamma significantly increased HLA-DR and ICAM-1 expression, whereas transforming growth factor-beta1 significantly decreased HLA-DR expression and lipopolysaccharide significantly increased ICAM-1 expression.

CONCLUSION

HLA-DR and ICAM-1 epithelial expression in nasal polyps in situ and in vitro and their in vitro modulation reinforce the active role of epithelial cells in chronic inflammatory diseases of the upper airways.

Very late antigen-4 in CD18-independent neutrophil emigration during acute bacterial pneumonia in mice

This study tested the hypothesis that very late antigen (VLA)-4 mediates CD18-independent neutrophil emigration into the airspaces induced by either Streptococcus pneumoniae, a stimulus that induces primarily CD18-independent neutrophil emigration, or Escherichia coli, toward which only 20-30% of the total number of neutrophils emigrate through CD18-independent pathways. In wild-type (WT) mice, VLA-4 expression was less on neutrophils that emigrated into the airspaces than on circulating neutrophils. Vascular cell adhesion molecule-1 (VCAM-1) mRNA, the major endothelial cell ligand for VLA-4, increased more in E. coli than in S. pneumoniae pneumonia. VCAM-1 protein expression was not detected in capillaries, the major site of neutrophil emigration. Neutrophil emigration during E. coli or S. pneumoniae pneumonia was similar in mice given antibodies against both CD18 and VLA-4 compared with mice given the anti-CD18 antibody and a control antibody. However, in hematopoietically reconstituted mice with both WT and CD18-deficient neutrophils in their blood, the migration of CD18-deficient neutrophils in response to S. pneumoniae was slightly but significantly less in animals pretreated with the anti-VLA-4 antibody than in those receiving a control antibody. These data suggest that VLA-4 plays a small role in CD18-independent neutrophil emigration, but the majority of CD18-independent neutrophil emigration induced by bacteria in the lungs occurs through VLA-4-independent mechanisms.

Oxysterols induce interleukin-1beta production in human macrophages

BACKGROUND

Oxysterols are biologically active molecules generated during the oxidation of low-density lipoprotein or formed enzymatically in vivo. In the atherosclerotic plaque newly recruited macrophages may be exposed to oxysterols present in the plaque. How these oxysterols affect the expression and secretion of inflammatory cytokines such as interleukin-1beta (IL-1beta) in macrophages is not known. Therefore the aim of the present study was to investigate how oxysterols regulate the expression and secretion of IL-1beta in human monocyte-derived macrophages.

METHODS

The IL-1beta messenger RNA (mRNA) expression was analysed by reverse transcription-polymerase chain reaction, and the IL-1beta protein secretion was measured by enzyme-linked immunosorbent assay.

RESULTS

A significant, dose-dependent increase in the secretion of IL-1beta was given by 25-hydroxycholesterol without the addition of lipopolysaccharide (LPS). At a concentration of 2.5 microg mL(-1) this increase was similar to that obtained by endotoxin (LPS, 1 microg mL(-1)). A transient increase in IL-1beta mRNA expression was found in macrophages incubated with 25-hydroxycholesterol compared with untreated controls. In addition, 25-hydroxycholesterol dramatically increased the IL-1beta secretion induced by LPS. At a concentration of 5 microg mL(-1) of 25-hydroxycholesterol the LPS-induced IL-1beta secretion was increased by about 25-fold. A similar tendency, but not so consistent, was found for 27-hydroxycholesterol.

CONCLUSIONS

Our results show that oxysterols, and 25-hydroxycholesterol in particular, may modulate the inflammatory response in human macrophages. Consequently the presence of oxysterols in atherosclerotic tissue may dramatically influence the effect of inflammation.

Tumor necrosis factor gene polymorphism in chronic sinusitis

OBJECTIVES

It is likely that genetic factors play a role in the etiology of chronic sinusitis, and airway inflammation is an important pathological feature in chronic sinusitis. We hypothesized that individuals with greater inflammatory responses may be more likely to acquire the disease. Polymorphisms of the tumor necrosis factor (TNF) genes have been described, and certain inflammatory diseases are reportedly associated with certain alleles of TNF genes. The purpose of this study is to examine whether there is an association between some alleles of TNF genes and chronic sinusitis.

STUDY DESIGN

Thirty-eight Japanese patients with intractable chronic sinusitis were selected on the basis of the following criteria: 1) persistent mucous or mucopurulent nasal discharge and/or postnasal dripping for longer than 3 years and 2) opacification in bilateral maxillary sinuses and ethmoid cells on plain radiographic films.

METHODS

Both tumor necrosis factor-alpha (TNF-alpha) and tumor necrosis factor-beta (TNF-beta) gene polymorphisms were analyzed by polymerase chain reaction (PCR) with restriction fragment length polymorphisms in these patients and 35 healthy control subjects.

RESULTS

A significantly higher frequency (P < .05) of TNFB*2 allele of TNF-beta gene polymorphism was observed in patients with chronic sinusitis (74%) compared with control subjects (56%). There was no association between alleles of TNF-alpha and chronic sinusitis.

CONCLUSION

We concluded that TNF-beta gene polymorphism may form a component of the genetic predisposition to chronic sinusitis in Japanese patients.