Clara cell 10-kDa protein expression in chronic rhinosinusitis and its cytokine-driven regulation in sinonasal mucosa

Updated epithelial barrier dysfunction in chronic rhinosinusitis: Targeting pathophysiology and treatment response of tight junctions

Tight junction (TJ) proteins establish a physical barrier between epithelial cells, playing a crucial role in maintaining tissue homeostasis by safeguarding host tissues against pathogens, allergens, antigens, irritants, etc. Recently, an increasing number of studies have demonstrated that abnormal expression of TJs plays an essential role in the development and progression of inflammatory airway diseases, including chronic obstructive pulmonary disease, asthma, allergic rhinitis, and chronic rhinosinusitis (CRS) with or without nasal polyps. Among them, CRS with nasal polyps is a prevalent chronic inflammatory disease that affects the nasal cavity and paranasal sinuses, leading to a poor prognosis and significantly impacting patients' quality of life. Its pathogenesis primarily involves dysfunction of the nasal epithelial barrier, impaired mucociliary clearance, disordered immune response, and excessive tissue remodeling. Numerous studies have elucidated the pivotal role of TJs in both the pathogenesis and response to traditional therapies in CRS. We therefore to review and discuss potential factors contributing to impair and repair of TJs in the nasal epithelium based on their structure, function, and formation process.

Systematic Review of Protein Biomarkers in Adult Patients With Chronic Rhinosinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) is a heterogeneous condition characterized by differing inflammatory endotypes. The identification of suitable biomarkers could enable personalized approaches to treatment selection.

OBJECTIVE

This study aimed to identify and summarize clinical studies of biomarkers in adults with CRS in order to inform future research into CRS endotypes.

METHODS

We conducted systematic searches of MEDLINE and Web of Science from inception to January 30, 2022 and included all clinical studies of adult CRS patients and healthy controls measuring biomarkers using enzyme-linked immunosorbent assays or Luminex immunoassays. Outcomes included the name and tissue type of identified biomarkers and expression patterns within CRS phenotypes. Study quality was assessed using the National Institutes of Health quality assessment tool for observational cohort and cross-sectional studies. A narrative synthesis was performed.

RESULTS

We identified 78 relevant studies involving up to 9394 patients, predominantly with CRS with nasal polyposis. Studies identified 80 biomarkers from nasal tissue, 25 from nasal secretions, 14 from nasal lavage fluid, 24 from serum, and one from urine. The majority of biomarkers found to distinguish CRS phenotypes were identified in nasal tissue, especially in nasal polyps. Serum biomarkers were more commonly found to differentiate CRS from controls. The most frequently measured biomarker was IL-5, followed by IL-13 and IL-4. Serum IgE, IL-17, pentraxin-3 and nasal phospho-janus kinase 2, IL-5, IL-6, IL-17A, granulocyte-colony stimulating factor, and interferon gamma were identified as correlated with disease severity.

CONCLUSION

We have identified numerous potential biomarkers to differentiate a range of CRS phenotypes. Future studies should focus on the prognostic role of nasal tissue biomarkers or expand on the more limited studies of nasal secretions and nasal lavage fluid.We registered this study in PROSPERO (CRD42022302787).

MEX3B inhibits collagen production in eosinophilic nasal polyps by downregulating epithelial cell TGFBR3 mRNA stability

Although the expression of Mex3 RNA-binding family member B (MEX3B) is upregulated in human nasal epithelial cells (HNECs) predominately in the eosinophilic chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP) subtype, its functions as an RNA binding protein in airway epithelial cells remain unknown. Here, we revealed the role of MEX3B based on different subtypes of CRS and demonstrated that MEX3B decreased the TGF-β receptor III (TGFBR3) mRNA level by binding to its 3' UTR and reducing its stability in HNECs. TGF-βR3 was found to be a TGF-β2-specific coreceptor in HNECs. Knocking down or overexpressing MEX3B promoted or inhibited TGF-β2-induced phosphorylation of SMAD2 in HNECs, respectively. TGF-βR3 and phosphorylated SMAD2 levels were downregulated in CRSwNP compared with controls and CRS without nasal polyps with a more prominent downregulation in the eosinophilic CRSwNP. TGF-β2 promoted collagen production in HNECs. Collagen abundance decreased and edema scores increased in CRSwNP compared with control, again more prominently in the eosinophilic type. Collagen expression in eosinophilic CRSwNP was negatively correlated with MEX3B but positively correlated with TGF-βR3. These results suggest that MEX3B inhibits tissue fibrosis in eosinophilic CRSwNP by downregulating epithelial cell TGFBR3 expression; consequently, MEX3B might be a valuable therapeutic target against eosinophilic CRSwNP.

Club cell 10-kDa protein (CC10) as a surrogate for identifying type 2 asthma phenotypes

Club cell 10-kDa protein (CC10) is a documented biomarker for airway obstructive diseases. Primarily produced by nonciliated club cells in the distal airway and in nasal epithelial cells, CC10 suppresses Th2 cell differentiation and Th2 cytokine production. In this study, we aimed to determine whether CC10 can also be used as an alternative biomarker for identifying Type 2 (T2) asthma.

74 patients with asthma, and 24 healthy controls were enrolled in the study. T2-high asthma was defined as elevation in two or more biomarkers, such as sputum eosinophilia ≥ 3%, high blood eosinophils ≥ 300/µL, or high FeNO ≥ 30 ppb. T2-low asthma was defined as no elevation in biomarkers. Enzyme-linked immunosorbent assay (ELISA) was used to assess the CC10 levels in plasma.

The plasma CC10 level in patients with T2-high asthma was lower than that of patients with T2-low asthma and healthy controls (P < 0.05). To distinguish between T2-high and T2-low phenotype in patients with asthma, a receiver-operating characteristic (ROC) analysis was performed. It showed a sensitivity of 58.1% and specificity of 78.0% when using 22.74 ng/ml of plasma CC10. Correlation analysis indicated that the plasma CC10 level was inversely correlated with sputum eosinophil, blood eosinophil, and FeNO, and positively correlated with log PD20. However, no correlation with sputum neutrophil percentages, macrophage percentages, IgE, or lung function was found.

Plasma CC10 is potentially useful in predicting T2-high and T2-low asthma. Lower plasma CC10 was associated with enhanced airway hyperresponsiveness, and Type 2 inflammation.

Characterization of the Notch pathway in nasal polyps of patients with chronic rhinosinusitis: A pilot study

Chronic rhinosinusitis with nasal polyps is a widespread pathology characterized by persistent inflammation of nasal and paranasal mucosa. Although it represents one of the most frequent diseases of the nasal cavities, its etiology is still not completely elucidated. There is evidence suggesting that the Notch signaling, a highly conserved intercellular pathway known to regulate many cellular processes, including inflammation, is implicated in nasal polyps formation. The purpose of this study was to investigate the expression of genes of the Notch pathway in nasal polyps from patients with chronic rhinosinusitis. Nasal polyps and adjacent mucosa tissue were obtained from 10 patients. RNA was analyzed by quantitative reverse transcriptase-polymerase chain reaction for the expression level of (1) Notch pathway components such as receptors (NOTCH1-4), ligands (DLL4, JAGGED-1), and target genes (HEY1, 2, and HES1) and (2) genes providing information on the pathogenesis of polyposis (C-MYC and SCGB1A1) and on eosinophils content (CCL26, IL5, and SAA2). We report a Notch-driven gene expression pattern in nasal polyps which correlates with the expression of genes highly expressed in eosinophils, whose presence is an important parameter to define the pathophysiologic diversity characterizing nasal polyps. Taken together, our results suggest a role for Notch signaling in the pathophysiology of polyposis. Further studies are needed to elucidate the role of Notch in nasal polyps formation and to establish whether it could represent a novel therapeutic target for this pathology.

Endoplasmic reticulum stress promotes local immunoglobulin E production in allergic rhinitis

BACKGROUND

The role of endoplasmic reticulum (ER) stress in the pathogenesis of allergic rhinitis (AR) remains elusive.

METHODS

Real-time polymerase chain reaction (RT-PCR), immunohistochemistry, and western blotting analyses were performed to detect the expression of ER stress and unfolded protein response markers: 78-kDa glucose-regulated protein (GRP78), C/EBP homologous protein (CHOP), activating transcription factor 6 (ATF6α), spliced X-box binding protein 1 (sXBP-1), and phosphorylated eukaryotic initiation factor 2α (p-eIF2α), in inferior turbinate tissue samples from patients with AR and non-AR controls. Nasal tissues from patients with AR were cultured ex vivo and treated with 4-phenylbutyric acid (4-PBA), an ER stress inhibitor.

RESULTS

Compared to those in non-AR controls, the mRNA and protein levels of GRP78, CHOP, ATF6α, sXBP-1, and p-eIF2α were significantly increased in nasal tissues from patients with AR. GRP78 and CHOP were mainly expressed in CD138+ plasma cells in nasal tissues from patients with AR. The frequency of IgE+CD138+ plasma cells was significantly higher in nasal tissues from patients with AR than that in non-AR controls. IgE levels in nasal secretions and tissues were positively correlated with GRP78 and CHOP mRNA levels in the nasal tissues. After 4-PBA treatment, the protein expression of GRP78, CHOP, ATF6α, sXBP-1, and p-eIF2α was significantly reduced in cultured AR-derived nasal tissues, and IgE levels were simultaneously decreased in cultured supernatants.

CONCLUSIONS

ER stress may be involved in the regulation of local IgE production in patients with AR. Inhibition of ER stress potentially provides a therapeutic avenue in AR by reducing local IgE production.

LEVEL OF EVIDENCE

NA.

Transplantation of human iPS cell-derived airway cells on vitrigel membrane into rat nasal cavity

The nasal mucosa functions as a frontline biological defense against various foreign substances and pathogens. Maintaining homeostasis of the nasal epithelium is necessary to promote good health. Nasal epithelia are constantly replaced under normal conditions. However, hereditary diseases, including primary ciliary dyskinesia and cystic fibrosis, can result in intractable dysfunction of the nasal mucosa. Since there is no treatment for this underlying condition, extrinsic manipulation is necessary to recover and maintain nasal epithelia in cases of hereditary diseases. In this study, we explored the use of airway epithelial cells (AECs), including multi-ciliated airway cells (MCACs), derived from human induced pluripotent stem cells (hiPSCs) on porcine atelocollagen vitrigel membranes, as a candidate of a therapeutic method for irreversible nasal epithelial disorders. To confirm the regenerative capacity of iPSC-derived AECs, we transplanted them into nasal cavities of nude rats. Although the transplanted cells were found within cysts isolated from the recipient nasal respiratory epithelia, they survived in some rats. Furthermore, the surviving cells were composed of multiple cell types similar to the human airway epithelia. The results could contribute to the development of novel transplantation-related technologies for the treatment of severe irreversible nasal epithelial disorders.

Application of Clinical Scores in the Differential Diagnosis of Chronic Rhinosinusitis With Nasal Polyps in a Chinese Population

Background

Eosinophilic (Eos) and non-eosinophilic (non-Eos) chronic rhinosinusitis with nasal polyps (CRSwNP) react differently to clinical treatment, with eosinophilic chronic rhinosinusitis with nasal polyps (Eos CRSwNP) being more likely to recur after surgery.

Objective

To explore the clinical value of the visual analog scale (VAS), nasal endoscopy score (Lund–Kennedy, L–K), computed tomography (CT) score (Lund–Mackay scoring system, L–M), and blood Eos percentage in the differential diagnosis of Eos CRSwNP and non-Eos CRSwNP.

Methods

Ninety-nine patients with CRSwNP were enrolled in this study and assigned to 2 groups (Eos CRSwNP and non-Eos CRSwNP). The blood Eos percentage and VAS, L–K, and L–M scores in the 2 groups of patients were compared. A receiver operating characteristic (ROC) was used to assess the usefulness of VAS, L–K, and L–M scores for differentiating Eos CRSwNP and non-Eos CRSwNP.

Results

There were significantly differences between the Eos CRSwNP group and non-Eos CRSwNP group in the following scores: blood Eos percentage, mean VAS score, olfaction/VAS, general discomfort/L–K, edema score/L–K, olfactory cleft (OC) score via endoscopy, mean L–M score, anteriorethmoid sinus score, posterior ethmoid sinus score, sphenoid sinus score, frontal sinus score, and OC score via CT. An ROC analysis showed that blood Eos percentage had the highest area under the ROC curve (AUC) value (0.749); however, several other scores (olfaction score/VAS, edema score/L–K, and mean L–M score) also had high AUC values. The combination of olfaction score/VAS and blood Eos percentage had the highest clinical convenience score as well as high sensitivity and specificity. A combination of cutoff values for the 2 predictors (blood Eos percentage ≥3.85%, olfaction score/VAS score ≥3) showed a sensitivity of 75.5% and a specificity of 78.0%.

Conclusion

The olfaction score/VAS score and the blood Eos percentage can be combined to differentiate Eos CRSwNP from non-Eos CRSwNP in a Chinese population.

Correlation of Nasal Fluid Biomarkers and Symptoms in Patients with Persistent Allergic Rhinitis

OBJECTIVES

This study investigated whether the biomarkers present in nasal fluid reflect the severity of symptoms in patients with persistent allergic rhinitis (PAR).

METHODS

We enrolled 29 PAR patients complaining of nasal symptoms and testing positive to skin prick test. Patients' total nasal symptom score (TNSS) was measured and their nasal lavage fluid (NALF) was collected. The levels of biomarkers including Clara cell protein 16 (CC16), tryptase, and interleukin 5 (IL-5) in NALF were determined via enzyme-linked immunosorbent assay (ELISA).

RESULTS

PAR patients were classified into persistent mild and persistent moderate-to-severe groups according to the Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines. The CC16 alone was significantly negatively correlated with TNSS (P < .05). Further, the CC16 level was significantly lower in persistent moderate-to-severe group than persistent mild group of patients (P < .05).

CONCLUSIONS

The levels of CC16 alone among several NALF biomarkers showed an inverse correlation with symptoms of PAR patients.

Clara cell protein 16 release from the nasal mucosa in allergic rhinitis, chronic rhinosinusitis, and exposure to air pollutants

Clara cell protein 16 (CC16) is a small protein mainly produced by non-ciliated Clara cells in the respiratory epithelium. It has an anti-inflammatory role in chronic upper and lower airway eosinophilic inflammations. Decreased levels of CC16 are found in the nasal secretions and plasma of patients with chronic eosinophilic inflammatory disorders, such as asthma, allergic rhinitis, and chronic rhinosinusitis with or without nasal polyps, as well as in people exposed to high levels of air pollutants. Intranasal corticosteroid administration suppresses chronic inflammation of the nasal mucosa driven by eosinophils and stimulates local CC16 production. CC16 can be a reliable biomarker of the beneficial effects of perennial allergic rhinitis and chronic rhinosinusitis therapy and of the functional recovery of the nasal mucosa after treatment with topical glucocorticoids.

Clara Cell 10 kDa Protein Alleviates Murine Hepatitis Virus Strain 3-Induced Fulminant Hepatitis by Inhibiting Fibrinogen-Like Protein 2 Expression

Background: Fulminant hepatitis (FH) is a serious threat to human life, accompanied by massive and rapid necroinflammation. Kupffer cells, the major immune cell population involved in innate immune responses, are considered to be central for FH. Fibrinogen-like protein 2 (Fgl2) is a pro-coagulant protein that is substantially induced in macrophages upon viral infection, and Fgl2 depletion represses murine hepatitis virus strain 3 (MHV-3) infection. Clara cell 10 kDa (CC10) protein is a secretory protein with anti-inflammatory properties in allergic rhinitis and asthma. However, its mechanisms of action and pathogenic roles in other disease are still unclear. In this study, we aimed to determine the role of CC10 in FH and the regulation of Fgl2 by CC10.

Methods: A mouse FH model was established by peritoneal injection of MHV-3. The mice received CC10 protein through tail vein injection before viral infection. Survival rate, liver function, liver histology, fibrin deposition, and necrosis were examined. The regulatory effect of CC10 on Fgl2 expression was investigated using THP-1 cells and mouse peritoneal macrophages in vitro.

Results: In the mouse FH model induced by MHV-3, the survival rate increased from 0 to 12.5% in the CC10 group compared to that in the saline-only control group. Meanwhile, the levels of ALT and AST in serum were significantly decreased and liver damage was reduced. Furthermore, hepatic Fgl2, TNF-α, and IL-1β expression was obviously downregulated together with fibrin deposition, and hepatocyte apoptosis was reduced after administration of CC10 protein. In vitro, CC10 was found to significantly inhibit the expression of Fgl2 in IFN-γ-treated THP-1 cells and MHV-3-infected mouse peritoneal macrophages by western blot and real-time PCR. However, there was no direct interaction between CC10 and Fgl2 as shown by co-immunoprecipitation. Microarray investigations suggested that HMG-box transcription factor 1 (HBP1) was significantly low in CC10-treated and IFN-γ-primed THP-1 cells. HBP1-siRNA treatment abrogated the inhibitory effect of CC10 on Fgl2 expression in Human Umbilical Vein Endothelial cells (HUVECs).

Conclusion:CC10 protects against MHV-3-induced FH via suppression of Fgl2 expression in macrophages. Such effects may be mediated by the transcription factor HBP1.

Multidimensional endotypes of chronic rhinosinusitis and their association with treatment outcomes

BACKGROUND

The expression of chronic rhinosinusitis (CRS) is multidimensional. Disease heterogeneity in patients with CRS remains poorly understood. This study aimed to identify endotypes of CRS using cluster analysis by integrating multidimensional characteristics and to explore their association with treatment outcomes.

METHODS

A total of 28 clinical variables and 39 mucosal cellular and molecular variables were analyzed using principal component analysis. Cluster analysis was performed on 246 prospectively recruited Chinese CRS patients with at least 1-year postoperative follow-up. Difficult-to-treat CRS was characterized in each generated cluster.

RESULTS

Seven subject clusters were identified. Cluster 1 (13.01%) was comparable to the classic well-defined eosinophilic CRS with polyps, having severe disease and the highest proportion of difficult-to-treat CRS. Patients in cluster 2 (16.26%) and cluster 4 (13.82%) had relatively lower proportions of presence of polyps and presented mild inflammation with moderate proportions of difficult-to-treat cases. Subjects in cluster 2 were highly atopic. Cluster 3 (7.31%) and cluster 6 (21.14%) were characterized by severe or moderate neutrophilic inflammation, respectively, and with elevated levels of IL-8 and high proportions of difficult-to-treat CRS. Cluster 5 (4.07%) was a unique group characterized by the highest levels of IL-10 and lacked difficult-to-treat cases. Cluster 7 (24.39%) demonstrated the lowest symptom severity, a low proportion of difficult-to-treat CRS, and low inflammation load. Finally, we found that difficult-to-treat CRS was associated with distinct clinical features and biomarkers in the different clusters.

CONCLUSIONS

Distinct clinicopathobiologic clusters of CRS display differences in clinical response to treatments and characteristics of difficult-to-treat CRS.

Association between impaired IL-10 production following exposure to Staphylococcus aureus enterotoxin B and disease severity in eosinophilic chronic rhinosinusitis

BACKGROUND

IL-10 is a major anti-inflammatory cytokine that prevents inflammation-mediated tissue damage. We characterized the production of IL-10 by sinonasal tissue cells following exposure to Staphylococcus aureus enterotoxin B (SEB), which elicits cellular responses and is associated with the pathogenesis of eosinophilic chronic rhinosinusitis (ECRS).

METHODS

Dispersed nasal polyp (NP) cells and uncinate tissue (UT) cells were prepared from patients with CRS with and without NP, respectively. Cells were incubated with SEB, and then the levels of IL-10 in the cell supernatants were determined. The effect of neutralizing IL-10 on SEB-induced IL-5, IL-13, IFN-γ, and IL-17A production was examined. Expression of IL-10 in NPs was also determined.

RESULTS

IL-10 was expressed in infiltrating inflammatory cells in NPs. NP cells, especially non-adherent NP cells, produced substantial amounts of IL-10 in response to SEB. Although baseline production of IL-10 was significantly higher in NP cells than UT cells, the degree of IL-10 response to SEB was not significantly different between the cell types. The degree of IL-10 production was negatively correlated with the degree of eosinophilia both in tissues and peripheral blood whereas positively correlated with the 1-s forced expiratory volume/forced vital capacity ratio. Patients with severe ECRS displayed a significant decrease in IL-10 production compared with those with non-ECRS. IL-10 neutralization significantly augmented SEB-induced IL-13 and IFN-γ production by NP cells.

CONCLUSIONS

Impaired IL-10 production in response to SEB in NP may exacerbate the pathophysiology of ECRS including eosinophilia and lower airway obstruction.

Expression of Clara cell 10-kDa protein and trefoil factor family 1 in patients with chronic rhinosinusitis and nasal polyps

The current study measured the expression of Clara cell 10-kDa protein (CC10) and trefoil factor family 1 (TFF1) in the sinus mucosa of patients exhibiting chronic rhinosinusitis (CRS) and nasal polyps (NP). CC10 and TFF1 expression in the sinus mucosa of the control group and patients with CRS and NP was determined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), western blotting and immunohistochemistry. The correlation between CC10 and TFF1 expression was further analyzed using Spearman's correlation analysis. The expression of TFF1 was significantly increased in the sinus mucosa of patients with CRS and NP, whereas CC10 expression was significantly decreased compared with controls. Spearman's correlation analysis identified a negative correlation between CC10 and TFF1 expression in the sinus mucosa of patients with CRS and NP. The results of immunohistochemistry and RT-qPCR were consistent with each other. Hematoxylin and eosin staining revealed notable lesions in the mucous membranes, goblet cells and cilia of sinus mucosa samples from patients with CRS and NP. The negative correlation between CC10 and TFF1 expression during the progression of CRS and NP suggest that CC10 and TFF1 may serve important roles in its pathogenesis.

Sinus Computed Tomographic Findings in Adult Smokers and Nonsmokers with Asthma. Analysis of Clinical Indices and Biomarkers

RATIONALE

When they occur together, sinusitis and asthma are often thought to represent anatomically separate components of the same chronic inflammatory airway disease. Information about the effect of smoking on the interaction between sinusitis and asthma in patients who have both disorders is limited.

OBJECTIVES

To evaluate the effect of cigarette smoking on the relationship between the presence and severity of sinusitis and selected asthma-related indices in adults who have asthma.

METHODS

This study included 127 patients with severe asthma and 79 patients with mild to moderate asthma. Clinical data were obtained from all subjects during a 2-day stay at Hokkaido University Hospital (Sapporo, Japan). The Lund-Mackay scoring system was used to assess the anatomic extent and severity of sinusitis as revealed by sinus computed tomographic (CT) images obtained during hospitalization. We examined associations between Lund-Mackay scores and a variety of asthma-related indices and levels of biomarkers in blood and sputum. To clarify the effect of smoking on these associations, we conducted separate analyses for nonsmoking (<10 pack-years; n = 130) and smoking subjects (≥10 pack-years; n = 76).

MEASUREMENTS AND MAIN RESULTS

In our cohort of adults with asthma, we found significant positive relationships between the presence and severity of sinusitis as assessed by Lund-Mackay score and the severity of asthma as measured by percent predicted FEV₁ or FEV₁/FVC for nonsmoking subjects (<10 pack-years) but not for cigarette smokers (>10 pack-years). Lund-Mackay scores correlated with blood and sputum eosinophil counts, serum IgE levels, and fractional exhaled nitric oxide, regardless of smoking status. Lund-Mackay scores also showed significant positive associations with serum periostin and chemokine C-C motif ligand 18 levels, regardless of smoking status, whereas a positive association with plasma osteopontin level was seen only for nonsmoking subjects.

CONCLUSIONS

We found an association between the severity of sinusitis on CT imaging and the severity of concomitant asthma on spirometry for nonsmoking adults but not for smokers. In adults with asthma, CT imaging evidence of severe sinusitis indicates intense Th2-related inflammation, regardless of smoking status.

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.

Role of Interleukin-10 on Nasal Polypogenesis in Patients with Chronic Rhinosinusitis with Nasal Polyps

Background and Objectives

Interleukin 10 (IL-10) is a potent anti-inflammatory cytokine. The dysregulation of IL-10 is associated with an enhanced immunopathologic response to infection, as well as with an increased risk for developing numerous autoimmune diseases. In this study, we investigated IL-10 expression in chronic rhinosinusitis with nasal polyps (CRSwNP) and assessed the possible role of IL-10 in the pathogenesis of CRSwNP.

Materials and Methods

Thirty-five patients with CRSwNP, 12 patients with chronic rhinosinusitis without NP (CRSsNP) and 10 control subjects were enrolled in this study. NP tissues and uncinated tissues (UT) were collected for analysis. Dispersed NP cells (DNPCs) were cultured in the presence or absence of IL-25 and IL-10, and a flow cytometric assay was performed to identify the constitutive cell populations of the DNPCs. Murine NP (n = 18) models were used for the in vivo experiments. Real-time PCR, immunohistochemistry, western blotting analysis and ELISA were performed to measure the expression levels of the selected inflammatory cytokines and inflammation-associated molecules.

Results

The mRNA expression levels of IL-10, IL-5, IL-17A, IL-25 and interferon gamma (IFN-γ) were significantly higher in the NP tissues than in the UT tissues. Strong positive correlations were observed between IL-10 and a variety of inflammatory cytokines (IL-5, IL-17A, IL-25, IFN-γ) and inflammation-associated molecules (B-cell activating factor; BAFF, CD19). Other than the IL-25 to IL-10 ratio, the expression ratios of the other measured inflammatory cytokines to IL-10 were significantly lower in the CRSwNP group than in the CRSsNP or control groups. Administrating IL-25 into the cultured DNPCs significantly increased the production of IL-10, but administrating IL-10 had no effect on the production of IL-25.

Conclusion

Increased expression of IL-10, IL-10 related inflammatory cytokine, and IL-10 related B cell activation indicated that IL-10, a potent anti-inflammatory cytokine, has a pivotal role in the pathogenesis of CRSwNPs.

Interaction of thymic stromal lymphopoietin, IL-33, and their receptors in epithelial cells in eosinophilic chronic rhinosinusitis with nasal polyps

BACKGROUND

Thymic stromal lymphopoietin (TSLP), IL-25, and IL-33 system contribute to the initiation and development of Th2 responses. This study aimed to explore the involvement of TSLP, IL-25, IL-33, and their receptors in type 2 T-helper (Th) responses in chronic rhinosinusitis with nasal polyps (CRSwNPs) and their cross-regulation in human nasal epithelial cells (HNECs).

METHODS

Immunohistochemistry, quantitative RT-PCR, ELISA, Bio-Plex assay, and flow cytometry were used to detect the expression of TSLP/common γ-like TSLP receptor (TSLPR)/IL-7 receptor α (IL-7Rα), IL-25/IL-17B receptor (IL-17RB), and IL-33/membrane-bound ST2 (ST2L)/soluble ST2 (sST2) in sinonasal mucosa and HNECs. HNECs cultured at an air-liquid interface were used to explore the expression in regulation of these cytokine systems.

RESULTS

Compared with controls and noneosinophilic CRSwNP, the expression of TSLP/TSLPR/IL-7Rα and ST2L/sST2 was significantly increased in eosinophilic CRSwNP, predominantly in epithelial cells. In contrast, the expression of IL-33 and IL-25/IL-17RB was enhanced in epithelial cells in both eosinophilic and noneosinophilic CRSwNP compared to controls. The expression of TSLP, TSLPR, and ST2L was positively correlated with symptom and computer tomography scan scores in eosinophilic CRSwNP and with Th2 cytokine expression in sinonasal mucosa. The expression of ST2L was correlated with TSLP and its receptor expression. TSLP could induce ST2L expression that promoted IL-33-induced TSLP expression in HNECs. In addition, TSLP/TSLPR/IL-7Rα and ST2L could be induced by Th2 cytokines, while IL-25/IL-17RB and IL-33 could be upregulated by Th1/Th17 cytokines, in HNECs.

CONCLUSIONS

The positive feedback loop between TSLP, IL-33 and their receptors, and Th2 cytokines may facilitate Th2-skewed inflammation in eosinophilic CRSwNP.

Clarithromycin and dexamethasone show similar anti-inflammatory effects on distinct phenotypic chronic rhinosinusitis: an explant model study

BACKGROUND

Phenotype of chronic rhinosinusitis (CRS) may be an important determining factor of the efficacy of anti-inflammatory treatments. Although both glucocorticoids and macrolide antibiotics have been recommended for the treatment of CRS, whether they have different anti-inflammatory functions for distinct phenotypic CRS has not been completely understood. The aim of this study is to compare the anti-inflammatory effects of clarithromycin and dexamethasone on sinonasal mucosal explants from different phenotypic CRS ex vivo.

METHODS

Ethmoid mucosal tissues from CRSsNP patients (n = 15), and polyp tissues from eosinophilic (n = 13) and non-eosinophilic (n = 12) CRSwNP patients were cultured in an ex vivo explant model with or without dexamethasone or clarithromycin treatment for 24 h. After culture, the production and/or expression of anti-inflammatory molecules, epithelial-derived cytokines, pro-inflammatory cytokines, T helper (Th)1, Th2 and Th17 cytokines, chemokines, dendritic cell relevant markers, pattern recognition receptors (PRRs), and tissue remodeling factors were detected in tissue explants or culture supernatants by RT-PCR or ELISA, respectively.

RESULTS

We found that both clarithromycin and dexamethasone up-regulated the production of anti-inflammatory mediators (Clara cell 10-kDa protein and interleukin (IL)-10), whereas down-regulated the production of Th2 response and eosinophilia promoting molecules (thymic stromal lymphopoietin, IL-25, IL-33, CD80, CD86, OX40 ligand, programmed cell death ligand 1, CCL17, CCL22, CCL11, CCL5, IL-5, IL-13, and eosinophilic cationic protein) and Th1 response and neutrophilia promoting molecules (CXCL8, CXCL5, CXCL10, CXCL9, interferon-γ, and IL-12), from sinonasal mucosa from distinct phenotypic CRS. In contrast, they had no effect on IL-17A production. The expression of PRRs (Toll-like receptors and melanoma differentiation-associated gene 5) was induced, and the production of tissue remodeling factors (transforming growth factor-β1, epidermal growth factor, basic fibroblast growth factor, platelet derived growth factor, vascular endothelial growth factor, and matrix metalloproteinase 9) was suppressed, in different phenotypic CRS by dexamethasone and clarithromycin in comparable extent.

CONCLUSIONS

Out of our expectation, our explant model study discovered herein that glucocorticoids and macrolides likely exerted similar regulatory actions on CRS and most of their effects did not vary by the phenotypes of CRS.

Histopathological evaluation of chronic rhinosinusitis: a critical review

BACKGROUND

Chronic rhinosinusitis (CRS) consists of a constellation of symptoms, including facial pressure/pain, hyposmia, rhinorrhea, and nasal congestion. On histopathological evaluation, the disease can be divided into pathophysiologically distinct subgroups. This study systematically reviews the literature regarding the unique histopathological findings of the various subtypes of CRS to determine the potential diagnostic value of performing tissue analysis of CRS specimens beyond routine hematoxylin and eosin (H&E) staining.

METHODS

A PubMed search was untaken to identify articles that evaluated the histopathological features of CRS. Six hundred fifty-four relevant articles were identified and after application of specific exclusion criteria, 71 articles were further reviewed in detail.

RESULTS

All articles included analysis of tissue samples from in-office biopsies or intraoperative specimens of patients who underwent sinus surgery. CRS was often further divided into subgroups and compared with each other and with a control group. The subgroups included CRS with and without nasal polyps, asthmatic and nonasthmatic patients, and with and without eosinophilia. Distinct inflammatory mediators were found for the different subgroups. Twenty-eight articles evaluated these inflammatory markers for their potential value as prognostic indicators.

CONCLUSION

CRS is a heterogeneous disease based on its histopathological findings. Information that is obtainable from light microscopy, but typically goes unreported, can serve as valuable prognostic indictors. However, routine H&E staining is suboptimal in distinguishing among the various subgroups of CRS. Assessment of specific inflammatory mediators in sinus mucosa specimens may help provide prognostic information and guide more tailored treatment for the individual patient.

Club cell 10-kDa protein attenuates airway mucus hypersecretion and inflammation

Bacterial lipopolysaccharide (LPS) and interleukin (IL)-13 increase mucus secretion and inflammatory cytokine production in normal human bronchial epithelial (NHBE) cells. We evaluated the effect of club cell 10-kDa protein (CC10), an anti-inflammatory protein produced by epithelial cells, on mucus secretion, cell morphology and inflammatory cytokine production.

NHBE cells were cultured at an air–liquid interface with CC10 or vehicle and exposed to LPS on day 14. Mucin MUC5AC, IL-8 and granulocyte-macrophage colony-stimulating factor were measured in cell supernatants. MUC5AC and IL-8 mRNA expression were measured by real-time PCR. Western blotting was used to evaluate nuclear factor (NF)-κB and extracellular signal-regulated kinase (ERK) activation. Cells were evaluated histologically. Additionally, NHBE cells were exposed to IL-13 and CC10 for 14 days, and secretion of the mucins MUC5AC and MUC5B was measured.

MUC5AC secretion stimulated either by LPS or by IL-13 was attenuated by CC10 at 20 ng·mL−1 (p<0.05). CC10 at 20 ng·mL−1 also attenuated IL-8 secretion (p<0.05). MUC5AC and IL-8 mRNA expression were also decreased by CC10 (p<0.05). CC10 attenuated phosphorylation of NF-κB (p<0.05) and ERK1/2 (p<0.05).

CC10 attenuates LPS-induced mucus secretion in airway cells, in part due to inhibition of NF-κB and ERK phosphorylation.

Respiratory viral infection in the chronic persistent phase of chronic rhinosinusitis

OBJECTIVES/HYPOTHESIS

The role of respiratory viral infection in the pathogenesis of chronic rhinosinusitis (CRS) has been rarely studied and remains controversial. The aim of this study was to explore the prevalence of respiratory viruses in the chronic status of CRS.

STUDY DESIGN

A case-control prospective study.

METHODS

Fifty-three control subjects, and 67 CRS with nasal polyp (CRSwNP) and 61 CRS without nasal polyp (CRSsNP) patients without signs of acute viral infection were enrolled. Epithelial cells scraped from the middle nasal meatus were tested for the nucleic acid of nine common respiratory viruses using polymerase chain reaction assay. The clinical disease severity was compared between subjects with and without viral infection.

RESULTS

The overall detection rate of viral infection was 75.47%, 68.66%, and 73.77% in controls, CRSwNP, and CRSsNP, respectively, and no significant difference among studied groups was observed. There was no significant difference in detection rate of any specific individual virus or multiple viruses among the groups studied either. Visual analog scale scores of symptoms, computed tomography scores, or endoscope scores did not show obvious difference between subjects with and without viral infection.

CONCLUSIONS

Although a high frequency of viral infection could be observed in the middle nasal meatus, no increase of frequency of viral infection could be demonstrated in chronic persistent phase of CRSsNP and CRSwNP. The contribution of the interaction between viral infection and host immunity to the pathogenesis of CRS remains to be determined.

LEVEL OF EVIDENCE

3b. Laryngoscope, 124:832-837, 2014.

Clara cell 10-kD protein in inflammatory upper airway diseases

PURPOSE OF REVIEW

To discuss the role of Clara cell 10-kD protein (CC10), an anti-inflammatory and immunomodulatory molecule, in inflammatory upper airway diseases, particularly in allergic rhinitis and chronic rhinosinusitis (CRS).

RECENT FINDINGS

CC10 expression is downregulated in allergic rhinitis and CRS. CC10 can inhibit the expression of chitinase 3-like 1 protein and osteopontin in eosinophilic CRS and allergic rhinitis, respectively. CC10 can also suppress osteopontin-induced expression of Th2 and proinflammatory cytokines in airway epithelial cells, and CC10 gene transfection can inhibit NF-κB activity in airway epithelial cells. Proinflammatory and Th2 cytokines can diminish CC10 production, whereas Th1 cytokines and interleukin-10 can promote CC10 production in sinonasal mucosa. Allergen exposure leads to a transdifferentiation of CC10 secreting cells into trefoil factor family 1 secreting cells and/or goblet cells in upper airways, resulting in the diminished expression of CC10.

SUMMARY

Allergen exposure and Th2 milieu can suppress the expression of CC10 in upper airways. CC10 can inhibit Th2-dominated eosinophilic inflammation in upper airways via multiple pathways.

Gene expression signatures: a new approach to understanding the pathophysiology of chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a complex inflammatory disease with variable disease manifestation. Though external risk factors are associated with development and/or persistence of CRS, the host mucosal response is also important, as nasal epithelium acts as a physical and immune barrier. Under inflammatory stress, the nasal epithelium can undergo injury, followed by a rapid remodeling response ranging from epithelial hyperplasia, to goblet-cell metaplasia, to denudation, loss of cilia, fibrosis, and basement membrane thickening. Identification of gene expression signatures and molecular pathways in CRS pathogenesis have now begun to contribute significantly to a better understanding of the genetic and molecular alterations underlying CRS development and progression. Genetic studies are especially illuminating when multiple gene variants synergize within a permissive environmental context, and are expected to guide development of more effective therapeutic targets for CRS treatment.

Clara cell 10-kDa protein inhibits T(H)17 responses through modulating dendritic cells in the setting of allergic rhinitis

BACKGROUND

T(H)17 responses have recently been implicated to play a role in allergic airway diseases, but their local expression in the setting of allergic rhinitis (AR) and their regulation in allergic airway diseases remain unclear.

OBJECTIVE

We sought to investigate the regulatory role of Clara cell 10-kDa protein (CC10), an endogenous regulator of airway inflammation, on T(H)17 responses in the setting of AR.

METHODS

Wild-type and homozygous CC10-null mice were used to establish an ovalbumin (OVA)-induced AR model. Human recombinant CC10 was given during sensitization or challenge. T(H)17 responses in human subjects and mice were examined by using flow cytometry, quantitative RT-PCR assay, immunohistochemistry, and ELISA. The direct effect of CC10 on T(H)17 cells and CD11c(+) dendritic cells (DCs) was studied by means of cell culture. Adoptive transfer was used to examine the influence of CC10-conditioned DCs on airway inflammation. The regulatory effect of CC10 on the expression of the CCL20 gene was tested by using the BEAS-2B cell line.

RESULTS

Compared with those of control subjects, T(H)17 responses were enhanced in the nasal mucosa of patients with AR. CC10-null mice with AR showed enhanced T(H)17 responses, and CC10 treatment significantly decreased T(H)17 responses. CC10 had no direct effect on in vitro T(H)17 cell differentiation. CC10 could significantly decrease the expression of OX40 ligand, IL-23, and IL-6 but enhance CD86 and TGF-β expression in DCs. Importantly, CC10 was able to inhibit T(H)17 cell polarization in the presence of OVA-pulsed DCs. CC10 pretreatment inhibited T(H)17 responses elicited by adoptive transfer of OVA-pulsed DCs. Furthermore, CC10 decreased the expression of CCL20 in BEAS-2B cells induced by inflammatory cytokines.

CONCLUSION

T(H)17 responses are enhanced in patients with AR, and CC10 inhibits T(H)17 responses through modulation of the function of DCs.

Clara cell 10-kDa protein gene transfection inhibits NF-κB activity in airway epithelial cells

BACKGROUND

Clara cell 10-kDa protein (CC10) is a multifunctional protein with anti-inflammatory and immunomodulatory effects. Induction of CC10 expression by gene transfection may possess potential therapeutic effect. Nuclear factor κB (NF-κB) plays a key role in the inflammatory processes of airway diseases.

METHOD/RESULTS

To investigate potential therapeutic effect of CC10 gene transfection in controlling airway inflammation and the underlying intracellular mechanisms, in this study, we constructed CC10 plasmid and transfected it into bronchial epithelial cell line BEAS-2B cells and CC10 knockout mice. In BEAS-2B cells, CC10's effect on interleukin (IL)-1β induced IL-8 expression was explored by means of RT-PCR and ELISA and its effect on NF-κB classical signaling pathway was studied by luciferase reporter, western blot, and immunoprecipitation assay. The effect of endogenous CC10 on IL-1β evoked IL-8 expression was studied by means of nasal explant culture. In mice, CC10's effect on IL-1β induced IL-8 and nuclear p65 expression was examined by immunohistochemistry. First, we found that the CC10 gene transfer could inhibit IL-1β induced IL-8 expression in BEAS-2B cells. Furthermore, we found that CC10 repressed IL-1β induced NF-κB activation by inhibiting the phosphorylation of IκB-α but not IκB kinase-α/β in BEAS-2B cells. Nevertheless, we did not observe a direct interaction between CC10 and p65 subunit in BEAS-2B cells. In nasal explant culture, we found that IL-1β induced IL-8 expression was inversely correlated with CC10 levels in human sinonasal mucosa. In vivo study revealed that CC10 gene transfer could attenuate the increase of IL-8 and nuclear p65 staining in nasal epithelial cells in CC10 knockout mice evoked by IL-1β administration.

CONCLUSION

These results indicate that CC10 gene transfer may inhibit airway inflammation through suppressing the activation of NF-κB, which may provide us a new consideration in the therapy of airway inflammation.

Overexpression of miR-125b, a novel regulator of innate immunity, in eosinophilic chronic rhinosinusitis with nasal polyps

RATIONALE

Eosinophilic chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP) represents a hard-to-treat subtype of CRS.

OBJECTIVES

To determine the pattern of expression and biologic role of microRNAs (miRNAs) in CRS, particularly in eosinophilic CRSwNP.

METHODS

Global miRNA expression in sinonasal mucosa from controls, CRS without nasal polyps (CRSsNP), and patients with eosinophilic CRSwNP was compared using miRNA microarrays. MiR-125b expression was detected by means of quantitative reverse-transcriptase polymerase chain reaction. The cellular localization of miR-125b was determined by in situ hybridization. MiR-125b functional assays were performed on airway epithelial cells and mice. MiR-125b expression regulation was studied by tissue and cell culture.

MEASUREMENTS AND MAIN RESULTS

CRSsNP and eosinophilic CRSwNP exhibited distinct miRNA expression profiles. MiR-125b was specifically up-regulated in eosinophilic CRSwNP. MiR-125b was mainly expressed by sinonasal and bronchial epithelial cells. EIF4E-binding protein 1 (4E-BP1) was identified as a direct target of miR-125b. MiR-125b mimic or inhibitor enhanced or decreased IFN-α/β production elicited by dsRNA in vitro or in vivo, respectively. 4E-BP1 expression was decreased, whereas IFN regulatory factor-7 and IFN-β expression was increased, in eosinophilic CRSwNP. IFN-β mRNA levels positively correlated with IL-5 mRNA levels and eosinophil infiltration in sinonasal mucosa. IFN-β stimulated B cell-activating factor of the tumor necrosis factor family production in airway epithelial cells. miR-125b could be induced by lipopolysaccharide, dsRNA, and IL-10.

CONCLUSIONS

The up-regulated expression of miR-125b may enhance type I IFN expression through suppressing 4E-BP1 protein expression in airway epithelial cells, which potentially contributes to mucosal eosinophilia in eosinophilic CRSwNP.

The cytokine-driven regulation of secretoglobins in normal human upper airway and their expression, particularly that of uteroglobin-related protein 1, in chronic rhinosinusitis

Background

The involvement of secretoglobins (SCGBs) other than SCGB1A1 (Clara cell 10-kDa protein, CC10) in human airway diseases remains unexplored. Among those SCGBs, SCGB3A2 (uteroglobin-related protein 1, UGRP1) is particularly interesting, given its structure and function similarities with SCGB1A1 (CC10). The aim of this study was to investigate the expression regulation of SCGBs other than SCGB1A1 (CC10) in human upper airway, and their potential involvement, particularly that of SCGB3A2 (UGRP1), in chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP) and without nasal polyps (CRSsNP).

Methods

Eight SCGB family members including SCGB3A2 (UGRP1), SCGB1C1 (ligand binding protein RYD5), SCGB1D1 (lipophilin A), SCGB1D2 (lipophilin B), SCGB1D4 (interferon-γ inducible SCGB), SCGB2A1 (mammaglobin 2), SCGB2A2 (mammaglobin 1), and SCGB3A1 (uteroglobin-related protein 2) were studied. The regulation of SCGBs mRNA expression in normal nasal mucosa by proinflammatory, Th1, and Th2 cytokines was studied through nasal explant culture. SCGBs mRNA expression levels in CRSsNP and CRSwNP patients and controls were compared. The mRNA levels were detected by means of quantitative reverse transcriptase-polymerase chain reaction. The protein expression of SCGB3A2 (UGRP1) was analyzed using immunohistochemistry.

Results

The expression of SCGBs except SCGB1D2 (lipophilin B) could be found in upper airway and be differentially regulated by different cytokines. SCGB3A2 (UGRP1) mRNA expression was induced by Th1 cytokine, but suppressed by proinflammatory and Th2 cytokines. SCGBs mRNA expression was altered in CRS; particularly, SCGB3A2 (UGRP1) protein and mRNA expression was markedly decreased in both CRSsNP and CRSwNP and its protein levels inversely correlated with the number of total infiltrating cells, preoperative sinonasal CT scores, and postoperative endoscopy and symptom scores.

Conclusion

SCGBs except SCGB1D2 (lipophilin B) are expressed in human upper airway and their expression can be differentially regulated by inflammatory cytokines. SCGBs mRNA expression is altered in CRS. Reduced production of UGRP1, which is likely due, at least in part, to a local cytokine environment, may contribute to the hyper-inflammation in CRS and correlates with response to surgery.

The expression of osteopontin and its association with Clara cell 10 kDa protein in allergic rhinitis

BACKGROUND

Osteopontin (OPN) is a multifunctional protein that has recently been linked to allergic diseases. Clara cell 10 kDa protein (CC10) is another protein linked to allergy, and has been suggested to have an inhibitory role in inflammatory airway diseases. At this time, it is not known whether OPN is involved in allergic rhinitis (AR) or if there is any association between CC10 and OPN in AR.

OBJECTIVE

To study the expression of OPN and its potential association with CC10 in AR.

METHODS

The expression of CC10 and OPN in nasal mucosa of AR patients was investigated. AR animal models were established by using wild-type and CC10-knockout mice. In some experiments, human recombinant CC10 protein was given to AR mice during either sensitization or challenge. The phenotypic changes were examined by histology and real-time RT-PCR. The direct effect of CC10 on the OPN expression in spleen mononuclear cells and on the OPN-induced inflammatory cytokine expression in BEAS-2B cells was measured through in vitro cell culture.

RESULTS

OPN expression was up-regulated, with a concomitant down-regulation of CC10, in AR patients, showing a significant negative correlation between their expression. Compared with control mice sensitized with PBS, the OPN expression was significantly increased in AR mice; such an increase was more prominent in CC10-knockout mice, compared with wild-type. Administration of CC10 during both sensitization and challenge could markedly ameliorate Th2-skewed inflammation and OPN expression in nasal mucosa. CC10 administration at the sensitization phase could also reduce spleen OPN expression. The in vitro study showed that CC10 directly down-regulated the OPN expression in spleen mononuclear cells stimulated with OVA and suppressed the OPN-induced expression of Th2 cytokines and pro-inflammatory cytokines in BEAS-2B cells.

CONCLUSION

In the context of allergic airway responses, CC10 can inhibit OPN expression and suppress the Th2-promoting function of OPN, resulting in CC10's inhibitory biological effects.

Transdifferentiation of Clara cell 10-kDa protein secreting cells in experimental allergic rhinitis

BACKGROUND

The reasons for the down-regulated Clara cell 10-kDa protein (CC10) expression in allergic rhinitis (AR) are unclear and the airway remodeling in AR has received little attention. This study explores epithelium remodeling and the change of CC10 secreting cells in AR by using a murine model.

METHODS

AR murine models were established by ovalbumin sensitization and challenge. In some mice, dexamethasone was given before each challenge. Histological changes of nasal mucosa were examined by means of hematoxylin and eosin and periodic acid-Schiff staining. CC10 and trefoil factor family (TFF) 1 expression were evaluated by immunohistochemistry.

RESULTS

In AR mice, both in turbinate and in septal mucosa, total cell number and the number of basal cells did not change; however, the number of dome-shaped cells decreased and the number of ciliated and goblet cells increased in turbinate mucosa, and the number of ciliated cells decreased and the number of goblet cells increased in septal mucosa. In turbinate mucosa, the number of CC10(+) cells (mainly dome-shaped cells) decreased whereas the number of TFF1(+) cells (mainly ciliated cells) increased. In septal mucosa, the number of CC10(+) and TFF1(+) cells (mainly ciliated cells) decreased simultaneously. Intermediate phenotypic goblet cells could express CC10 and TFF1. CC10 and TFF1 could be localized in the same cells. Dexamethasone reversed the changes of epithelium significantly.

CONCLUSION

Allergen exposure leads to a possible transdifferentiation of CC10 secreting cells into TFF1 secreting cells and/or goblet cells in upper airways. Nasal turbinate and septal epithelium display different patterns of transdifferentiation.

Clara cell 10-kD protein suppresses chitinase 3-like 1 expression associated with eosinophilic chronic rhinosinusitis

RATIONALE

Clara cell 10-kD (CC10) protein, an antiinflammatory molecule, is involved in inflammatory upper airway diseases, but its regulatory role is unclear, particularly in the process of chronic rhinosinusitis (CRS).

OBJECTIVES

To investigate the regulatory mechanisms of CC10 in eosinophilic CRS (ECRS) using an allergic mouse model.

METHODS

Homozygous CC10-knockout mice were used to establish an allergic ECRS model. Phenotypic changes were examined by histology, cytokine ELISA, and gene microarray analysis. Differential expression of chitinase 3-like 1 (CHI3L1) was verified by quantitative reverse transcriptase-polymerase chain reaction and immunohistochemistry. The functional role of CHI3L1 in vivo was assessed by the use of anti-CHI3L1 antibody in ECRS mice. CHI3L1 gene expression regulated by inflammatory cytokines and CC10 protein was performed using BEAS-2B cell line.

MEASUREMENTS AND MAIN RESULTS

Compared with wild-type mice, a significantly greater extent of inflammatory cell infiltration and tissue remodeling was found in CC10-knockout ECRS mice, which was associated with significantly higher levels of various cytokines and eotaxin-1. CHI3L1 was up-regulated in ECRS mice with a significant further increase in CC10-knockout mice. Anti-CHI3L1 treatment markedly ameliorated eosinophilic inflammation. Furthermore, nasal mucosal CC10 gene transfer in CC10-knockout mice attenuated eosinophilic inflammation and suppressed the levels of CHI3L1. Moreover, significantly up-regulated expression of CHI3L1 was noted in human ECRS. IL-1beta, tumor necrosis factor-alpha, and IL-13 were found to up-regulate CHI3L1 expression in BEAS-2B cells, whereas CC10 inhibited such up-regulation.

CONCLUSIONS

These results suggest that CHI3L1 is a novel molecule involved in ECRS and that CC10 plays a regulatory role in ECRS, presumably by attenuating CHI3L1 expression.

Chronic rhinosinusitis with and without nasal polyps is associated with decreased expression of glucocorticoid-induced leucine zipper

BACKGROUND

Chronic rhinosinusitis without nasal polyps (CRSsNP) and with nasal polyps (CRSwNP) is characterized by persistent inflammation of sinonasal mucosa. Glucocorticoid-induced leucine zipper (GILZ) is a recently described anti-inflammatory mediator.

OBJECTIVE

Here we analysed the expression of GILZ in CRSsNP and CRSwNP, its association with response to surgery, and its cytokine-driven expression regulation in the upper airways. Methods The messenger RNA (mRNA) and protein expression of GILZ in 33 CRSsNP, 32 CRSwNP, and 11 control samples was assessed by means of a quantitative RT-PCR and immunohistochemistry, respectively. Nasal explant culture was used to investigate the effect of IFN-gamma, IL-4, IL-13, IL-1beta, and TNF-alpha on GILZ mRNA expression in normal sinonasal mucosa.

RESULTS

The GILZ mRNA and protein expression was significantly suppressed in both CRSsNP and CRSwNP patients compared with controls. No significant difference in GILZ expression was found between CRSsNP and CRSwNP patients. Comparing patients responsive and patients recalcitrant to surgery, a significant further decrease of GILZ expression was found in recalcitrant patients both in the CRSsNP and in the CRSwNP group. IL-1beta, TNF-alpha, IL-4, and IL-13 reduced, whereas IFN-gamma enhanced GILZ mRNA levels in the sinonasal mucosa.

CONCLUSION

Down-regulated expression of GILZ may contribute to the pathogenesis of CRSsNP and CRSwNP and associate with response to surgery. GILZ expression in the upper airways can be regulated differentially by different cytokines.