Yukako Okamoto

Background/Objectives: Chronic rhinosinusitis with nasal polyps (CRSwNP) is associated with epithelial remodeling, impaired mucociliary clearance, and altered nitric oxide (NO) metabolism. However, cell type-specific mechanisms underlying epithelial NO signaling remain poorly understood. This study investigated NO-related signaling in differentiated human sinonasal epithelial cells. Methods: Human sinonasal tissues were obtained from patients with CRSwNP (n = 20) and control subjects (n = 20). Air–liquid interface (ALI) cultures were established from donor-derived epithelial cells. Ciliated and non-ciliated cells were identified by immunostaining for acetylated α-tubulin and BCAM. Expression of inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) was analyzed by quantitative RT-PCR. Intracellular NO-related fluorescence signals were evaluated using DAF-FM fluorescence imaging. Results: CRSwNP tissues exhibited significantly increased iNOS expression and elevated iNOS/eNOS ratios, whereas eNOS expression did not differ significantly from that in controls. ALI cultures reproduced differentiated sinonasal epithelium containing both ciliated and non-ciliated cell populations. DAF-FM fluorescence signals were significantly higher in ciliated cells than in non-ciliated cells (80.3 ± 25.3 vs. 49.3 ± 21.1). Non-selective NOS inhibition markedly reduced fluorescence signals in both cell types, whereas selective iNOS inhibition reduced but did not abolish signals in ciliated cells. Conclusions: NO-related signaling appears to differ among epithelial cell subtypes. Persistence of fluorescence signals after selective iNOS inhibition suggests a contribution of constitutive NOS activity in ciliated cells, whereas non-ciliated cells appear to rely more heavily on iNOS-dependent pathways. These findings support the hypothesis that altered epithelial NO signaling contributes to epithelial dysfunction and impaired mucociliary homeostasis in CRSwNP.

Background/Objectives: Chronic rhinosinusitis with nasal polyps (CRSwNP) is charac-terized by epithelial remodeling, impaired mucociliary clearance, and altered nitric oxide (NO) metabolism. However, the cell type–specific mechanisms of NO production and the functional roles of nitric oxide synthase (NOS) isoforms in sinonasal epithelial cells remain unclear. This study investigated NO production dynamics in air–liquid in-terface (ALI) cultures of human sinonasal epithelial cells. Methods: Human sinonasal epithelial cells were differentiated under ALI conditions. Expression of inducible NOS (iNOS) and endothelial NOS (eNOS) was analyzed by quantitative RT-PCR. Intracellular NO production was evaluated using the NO-sensitive fluorescent probe DAF-FM com-bined with laser scanning confocal microscopy. Cell type–specific NO production was examined in ciliated and non-ciliated epithelial cells using the NOS inhibitors L-NAME and 1400W. Results: CRSwNP tissues demonstrated significantly increased iNOS ex-pression and elevated iNOS/eNOS ratios compared with controls, whereas eNOS ex-pression showed no significant difference. ALI cultures successfully reproduced dif-ferentiated sinonasal epithelium containing ciliated and basal cells. DAF-FM fluores-cence revealed significantly greater NO production in ciliated epithelial cells than in non-ciliated cells. Non-selective NOS inhibition by L-NAME markedly suppressed NO production in both cell types, whereas selective iNOS inhibition by 1400W reduced but did not abolish NO production in ciliated cells. Conclusions: NO production mecha-nisms differ according to sinonasal epithelial cell subtype. Ciliated epithelial cells maintain both eNOS- and iNOS-dependent NO production, whereas non-ciliated cells predominantly rely on iNOS-derived NO. Dysregulated spatial NO signaling associated with ciliated cell loss may contribute to epithelial dysfunction and chronic inflammation in CRSwNP.

Background: The nasal septal swell body (NSB) is a thickened area of the nasal septum with erectile tissues, located above the nasal floor. We hypothesized that the presence of the NSB in this space exerts favorable effects to generate laminar nasal airflow by developing its morphology as adjusted to nasal septal deviation (NSD). Patients and Methods: We objectively measured the NSB morphology in 152 patients by computed tomography (CT) and assessed its relationship with the width of the inferior turbinate (IT), the severity of NSD, and the patency of the nasal airflow passage (NAP). Results: In the patients with moderate or severe NSD, the mean widths of the NSB, IT, and NAP were significantly narrower at the convex side compared to the paired concave side, with the degree being more prominent in the severe-NSD group. A positive correlation was observed between the degree of the NSD angles and the difference in the widths of the NSB (r = 0.805) and IT (r = 0.609). Conclusions: These results imply novel roles of the NSB in the maintenance of physiological nasal airflow to generate a laminar airflow from the nostrils toward the middle nasal meatus at a constant rate.

The planar cell polarity (PCP) of epithelial ciliated cells is essential for effective mucociliary clearance (MCC) in the sinonasal mucosa. We hypothesize that MCC coordination is impaired in nasal polyp (NP) mucosae due to the suppressed expression of a series of CPLANE (ciliogenesis and planar cell polarity effector) complex proteins in chronic rhinosinusitis (CRS) patients. To investigate this hypothesis, we subjected sinonasal mucosal samples to live video recording to measure mucociliary transport velocity (MCTV) and scanning electron microscopy to evaluate surface morphology. The expression and distribution of a panel of PCP proteins, e.g., WDPCP and FUZ, were investigated in relation to inflammatory cytokine levels and clinical features. The mean MCTV of NP mucosae was significantly lower than that of the inferior turbinate mucosae. The CRS group with NPs (CRSwNP group) (n = 28) showed increased expression of IL-13 and CCL26 mRNA compared to CRS patients without NPs (n = 25) and controls (n = 30). WDPCP and FUZ mRNA levels were significantly decreased in NP mucosae compared to ethmoid sinus mucosae in CRSwNP patients. WDPCP protein distribution was reduced in the cytoplasmic region of ciliated cells in CRSwNP patients. We conclude that suppression of WDPCP in ciliated cells is responsible for the impaired MCC of nasal polyps with type-2 inflammation. This mechanism might explain the decreased clearance and the potential for worsening symptoms of CRSwNP.

The planar cell polarity (PCP) of epithelial ciliated cells is essential for effective mucociliary clearance (MCC) in the sinonasal mucosa. We hypothesize that MCC coordination is impaired in nasal polyp (NP) mucosae due to suppressed expression of a series of CPLANE (ciliogenesis and planar cell polarity effector) complex proteins in chronic rhinosinusitis (CRS) patients. To inves-tigate this hypothesis, we subjected sinonasal mucosal samples to live video recording to measure mucociliary transport velocity (MCTV) and scanning electron microscopy to evaluate surface morphology. The expression and distribution of a panel of PCP proteins, e.g. WDPCP and FUZ, were investigated in relation to inflammatory cytokine levels and clinical features. The mean MCTV of NP mucosae was significantly lower than that of the inferior turbinate mucosae. The CRS group with NPs (CRSwNP group) (n=28) showed increased expression of IL-13 and CCL26 mRNA compared to CRS patients without NPs (n=25) and controls (n=30). WDPCP and FUZ mRNA levels were significantly decreased in NP mucosae compared to ethmoid sinus mucosae in CRSwNP patients. WDPCP protein distribution was reduced in the cytoplasmic region of ciliated cells in CRSwNP patients. We conclude that suppression of WDPCP in ciliated cells is responsible for the impaired MCC of nasal polyps with type-2 inflammation. This mechanism might explain the decreased clearance and the potential for worsening symptoms of CRSwNP.

Objectives: The cytokine oncostatin M (OSM) elicits pathogenic effects involving disruption of the epithelial barrier function as a part of immunological response networks. It is unclear how these integrated cytokine signals influence inflammation and other physiological processes in the pathology of chronic rhinosinusitis (CRS). We investigated the expression and distribution of OSM and OSM receptor (OSMR) in CRS patients’ sinonasal specimens, and we compared the results with a panel of inflammatory cytokine levels and clinical features. Patients and Methods: We classified CRS patients as eosinophilic (ECRS, n = 36) or non-eosinophilic (non-ECRS, n = 35) based on the Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis phenotypic criteria and compared their cases with those of 20 control subjects. We also examined OSM’s stimulatory effects on cytokine receptor expression levels using the human bronchial epithelium cell line BEAS-2B. Results: RT-PCR showed that the OSM mRNA levels were significantly increased in the CRS patients’ ethmoid sinus mucosa. The OSM mRNA levels were positively correlated with those of TNF-α, IL-1β, IL-13, and OSMR-β. In BEAS-2B cells, OSM treatment induced significant increases in the OSMRβ, IL-1R1, and IL-13Ra mRNA levels. Conclusions: OSM is involved in the pathogenesis of CRS in both type 1 and type 2 inflammation, suggesting the OSM signaling pathway as a potential therapeutic target for modulating epithelial stromal interactions.

Objectives: Oncostatin M (OSM), a member of the interleukin (IL)-6 family of cytokines, is known to elicit pathogenic effects involving disruption of the epithelial barrier function as a part of immunological response networks. It is not yet known how these integrated cytokine signals influence inflammation and other physiological processes in the pathology of chronic rhinosinusitis (CRS). We investigated the expression and distribution of OSM and OSM receptor (OSMR) in sinonasal specimens of CRS patients, and we compared the results with a panel of inflammatory cytokine levels and clinical features. Materials and Methods: We classified CRS patients as eosinophilic (ECRS, n=36) or non-eosinophilic (non-ECRS, n=35) based on the Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis (JESREC) phenotypic criteria, and we compared their cases with those of 68 non-CRS subjects. We also examined stimulatory effects of OSM on the expression levels of cytokine receptors by using the human bronchial epithelium cell line BEAS-2B. Results: An RT-PCR showed that the OSM mRNA levels were significantly increased in the ethmoid sinus mucosa of the CRS patients. The OSM mRNA levels were positively correlated with those of TNF-, IL-1, IL-13, and OSMR-. In BEAS-2B cells, OSM treatment induced significant increases in the OSMR-β, IL-1R1, and IL-13Ra mRNA levels. Conclusions: Our findings indicate that OSM is involved in the pathogenesis of CRS in both type 1 and type 2 inflammation, suggesting the OSM signaling pathway as a potential therapeutic target for modulating epithelial stromal interactions.

The bitter taste receptors (T2Rs) expressed in human sinonasal mucosae are known to elicit innate immune responses involving the release of nitric oxide (NO). We investigated the expression and distribution of two T2Rs, T2R14 and T2R38, in patients with chronic rhinosinusitis (CRS) and correlated the results with fractional exhaled NO (FeNO) levels and genotype of the T2R38 gene (TAS2R38). Using the Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis (JESREC) phenotypic criteria, we identified CRS patients as either eosinophilic (ECRS, n = 36) or non-eosinophilic (non-ECRS, n = 56) patients and compared these groups with 51 non-CRS subjects. Mucosal specimens from the ethmoid sinus, nasal polyps, and inferior turbinate were collected from all subjects, together with blood samples, for RT-PCR analysis, immunostaining, and single nucleotide polymorphism (SNP) typing. We observed significant downregulation of T2R38 mRNA levels in the ethmoid mucosa of non-ECRS patients and in the nasal polyps of ECRS patients. No significant differences in T2R14 or T2R38 mRNA levels were found among the inferior turbinate mucosae of the three groups. Positive T2R38 immunoreactivity was localized mainly in epithelial ciliated cells, whereas secretary goblet cells generally showed lack of staining. The patients in the non-ECRS group showed significantly lower oral and nasal FeNO levels compared with the control group. There was a trend towards higher CRS prevalence in the PAV/AVI and AVI/AVI genotype groups as compared to the PAV/PAV group. Our findings reveal complex but important roles of T2R38 function in ciliated cells associated with specific CRS phenotypes, suggesting the T2R38 pathway as a potential therapeutic target for promotion of endogenous defense mechanisms.