Immunolocalization of NLRP3 Inflammasome in Normal Murine Airway Epithelium and Changes following Induction of Ovalbumin-Induced Airway Inflammation.

Little is known about innate immunity and components of inflammasomes in airway epithelium. This study evaluated immunohistological evidence for NLRP3 inflammasomes in normal and inflamed murine (Balb/c) airway epithelium in a model of ovalbumin (OVA) induced allergic airway inflammation. The airway epithelium of control mice exhibited strong cytoplasmic staining for total caspase-1, ASC, and NLRP3, whereas the OVA mice exhibited strong staining for active caspase-1, with redistribution of caspase-1, IL-1ß and IL-18, indicating possible activation of the NLRP3 inflammasome. Active caspase-1, NLRP3, and other inflammasome components were also detected in tissue eosinophils from OVA mice, and may potentially contribute to IL-1ß and IL-18 production. In whole lung, inRNA expression of NAIP and procaspase-1 was increased in OVA mice, whereas NLRP3, IL-1ß and IL-18 decreased. Some OVA-treated mice also had significantly elevated and tightly correlated serum levels of IL-1ß and TNFα. In cultured normal human bronchial epithelial cells, LPS priming resulted in a significant increase in NLRP3 and II-lp protein expression. This study is the first to demonstrate NLRP3 inflammasome components in normal airway epithelium and changes with inflammation. We propose activation and/or luminal release of the inflammasome is a feature of allergic airway inflammation which may contribute to disease pathogenesis.

Aberrant mucin glycoprotein patterns of chronic rhinosinusitis patients with bacterial biofilms.

BACKGROUND: Increasingly bacterial biofilms have been implicated in chronic rhinosinusitis (CRS), and conventional treatment methods have failed to completely eradicate biofilms. (1) Terminal sialic acids present on sinus mucosal glycoproteins are targets for bacterial adherence and biofilm formation. (2) A subpopulation of CRS patients is more susceptible to biofilm formation due to aberrant terminal sialic residue distribution patterns of glycoproteins on their mucosa. (3) The higher levels of sialyl transferase (ST)6Gal1 gene expression contribute to the overall aberrant glycosylation patterns on the host mucosa that predispose this patient cohort to developing biofilms. (4) Mucin glycoprotein MUC7 that has known bactericidal activity displays an overall reduced terminal sugar profile in biofilm positive CRS patients. METHODS: Confocal scanning laser microscopy, glycoarray analysis, real-time polymerase chain reaction of ST6Gal1, neuraminidase assays and multivariate analysis were used to compare production of sialic acid-degrading enzymes in sinus biopsies from biofilm positive and negative CRS patients with mucosa from healthy controls. RESULTS: Biofilm-positive CRS patients expressed aberrant glycoprotein patterns with terminal sialics of between 70 and 90 kD (stress value = 0.1414). The ST6Gal1 gene was upregulated, and bacteria isolated from these patients exhibit significantly higher neuraminidase activity (p = 0.0343). We detected a significant lack in the overall expression of terminal sugar residues of MUC7 (stress value = 0.088). CONCLUSIONS: We observed a strong positive correlation between the aberrant terminal sugar patterns in this sub group of CRS patients with biofilms. The innate immunity function of their MUC7 glycoprotein against bacterial invasion may be compromised in CRS patients.

Immunomodulatory effect of cytosine-phosphate-guanosine (CpG)-oligonucleotides in nonasthmatic chronic rhinosinusitis: an explant model.

BACKGROUND: The use of cytosine-phosphate-guanosine-oligodeoxynucleotides (CpG-ODNs) or immunostimulatory sequences (ISSs) in the treatment of airway diseases is gaining interest. Binding of the CpG-ODN ligand to Toll-like receptor 9 (TLR9) triggers a shift from a Th2- to a Th1-type response in the target tissue. In this study, we explored the potential use of CpG-ODN to dampen the predominantly Th2-driven chronic inflammatory state in our cohort of patients. METHODS: An in vitro explant model comprising of sinonasal tissue from patients with asthma (n = 12) and without asthma (n = 11) were stimulated with CpG-ODN or Staphylococcus aureus enterotoxin B (SEB) or CpG-ODN in combination with SEB for 48 hours. Ten of the 12 asthma patients had nasal polyps. RNA was extracted for multiplex real-time reverse transcription polymerase chain reaction analysis and the 2(-delta deltaC(T)) method used to determine interleukin (IL)-5, p35 IL-12, interferon (IFN) gamma, and TLR9 expression levels. RESULTS: CpG-ODN significantly reduced IL-5 mRNA expression in patients without asthma (p = 0.0379) but not in the asthma-associated group. SEB alone caused an increase in IL-5 levels that could be dampened when CpG-ODN was added in combination with SEB. Significant differences in mean IL-5 expression levels between the asthmatic and nonasthmatic categories were detected (Welch t-test; **p = 0.0041). Asthmatic and nonasthmatic patients present as two distinct categories as reflected by significant differences in their IL-5 response to CpG-ODN (F = 11.93; ***p = 0.0008), SEB (F = 41.34; *p = 0.0476) and CpG-ODN with SEB (F = 13.2; *p = 0.0114). In contrast, no significant differences were observed in the expression levels of IL-12, IFN-gamma, and TLR9. CONCLUSION: Localized application of CpG-ODN on its own or in combination with SEB may potentially reduce the expression of the proinflammatory cytokine IL-5 in nonasthmatic patients and may be further developed as an immunotherapeutic agent.