Search

Background: Primary human airway epithelial cells cultured in an air-liquid interface (ALI) develop a well-differentiated epithelium. However, neither characterization of mucociliar differentiation overtime nor the inflammatory function of reconstituted nasal polyp (NP) epithelia have been described. Objectives: 1st) To develop and characterize the mucociliar differentiation overtime of human epithelial cells of chronic rhinosinusitis with nasal polyps (CRSwNP) in ALI culture system; 2nd) To corroborate that 3D in vitro model of NP reconstituted epithelium maintains, compared to control nasal mucosa (NM), an inflammatory function. Methods: Epithelial cells were obtained from 9 NP and 7 control NM, and differentiated in ALI culture for 28 days. Mucociliary differentiation was characterized at different times (0, 7, 14, 21, and 28 days) using ultrastructure analysis by electron microscopy; ΔNp63 (basal stem/progenitor cell), β-tubulin IV (cilia), and MUC5AC (goblet cell) expression by immunocytochemistry; and mucous (MUC5AC, MUC5B) and serous (Lactoferrin) secretion by ELISA. Inflammatory function of ALI cultures (at days 0, 14, and 28) through cytokine (IL-8, IL-1β, IL-6, IL-10, TNF-α, and IL-12p70) and chemokine (RANTES, MIG, MCP-1, IP-10, eotaxin-1, and GM-CSF) production was analysed by CBA (Cytometric Bead Array). Results: In both NP and control NM ALI cultures, pseudostratified epithelium with ciliated, mucus-secreting, and basal cells were observed by electron microscopy at days 14 and 28. Displaying epithelial cell re-differentation, β-tubulin IV and MUC5AC positive cells increased, while ΔNp63 positive cells decreased overtime. No significant differences were found overtime in MUC5AC, MUC5B, and lactoferrin secretions between both ALI cultures. IL-8 and GM-CSF were significantly increased in NP compared to control NM regenerated epithelia. Conclusion: Reconstituted epithelia from human NP epithelial cells cultured in ALI system provides a 3D in vitro model that could be useful both for studying the role of epithelium in CRSwNP while developing new therapeutic strategies, including cell therapy, for CRSwNP. [ABSTRACT FROM AUTHOR]

Background: Chronic rhinosinusitis with nasal polyps (CRSwNP) is a chronic inflammatory disease of the upper airways frequently associated with asthma. Bacterial infection is a feature of CRSwNP that can aggravate the disease and the response to glucocorticoid treatment. Objective: We examined whether the bacterial product lipopolysaccharide (LPS) reduces glucocorticoid receptor (GR) function in control nasal mucosa (NM) fibroblasts and in nasal polyp (NP) fibroblasts from patients with CRSwNP and asthma. Methods: NP (n = 12) and NM fibroblasts (n = 10) were in vitro pre-incubated with LPS (24 hours) prior to the addition of dexamethasone. Cytokine/chemokine secretion was measured by ELISA and Cytometric Bead Array. GRα, GRβ, mitogen-activated protein-kinase phosphatase-1 (MKP-1) and glucocorticoid-induced leucine zipper (GILZ) expression was measured by RT-PCR and immunoblotting, GRα nuclear translocation by immunocytochemistry, and GRβ localization by immunoblotting. The role of MKP-1 and GILZ on dexamethasone-mediated cytokine inhibition was analyzed by small interfering RNA silencing. Results: Pre-incubation of nasal fibroblasts with LPS enhanced the secretion of IL-6, CXCL8, RANTES, and GM-CSF induced by FBS. FBS-induced CXCL8 secretion was higher in NP than in NM fibroblasts. LPS effects on IL-6 and CXCL8 were mediated via activation of p38α/β MAPK and IKK/NF-κB pathways. Additionally, LPS pre-incubation: 1) reduced dexamethasone’s capacity to inhibit FBS-induced IL-6, CXCL8 and RANTES, 2) reduced dexamethasone-induced GRα nuclear translocation (only in NM fibroblasts), 3) did not alter GRα/GRβ expression, 4) decreased GILZ expression, and 5) did not affect dexamethasone’s capacity to induce MKP-1 and GILZ expression. MKP-1 knockdown reduced dexamethasone’s capacity to suppress FBS-induced CXCL8 release. Conclusion: The bacterial product LPS negatively affects GR function in control NM and NP fibroblasts by interfering with the capacity of the activated receptor to inhibit the production of pro-inflammatory mediators. This study contributes to the understanding of how bacterial infection of the upper airways may limit the efficacy of glucocorticoid treatment. [ABSTRACT FROM AUTHOR]

Background: Recent studies have revealed that cyclooxygenase-2 (COX-2) expression is down-regulated in aspirin-induced asthma (AIA). Various signal pathways (MAPKs, NF-κB and C/EBP) are involved in COX-2 regulation. Objective: To investigate the regulation of COX-2 expression through MAP-kinase pathway activation and nuclear factor translocation in aspirin-induced asthma (AIA). Methods: Fibroblasts were isolated from specimens of nasal mucosa (NM, N = 5) and nasal polyps (NP, N = 5). After IL-1β (1 ng/ml) incubation, COX-2 and phosphorylated forms of ERK, JNK and p38 MAPK were measured by Western blot. MAPK's role in IL-1β-induced COX-2 expression was assessed by treating cells with ERK (PD98059), JNK (SP600125) and p38 MAPK (SB203580) inhibitors (0.1-10 μM) prior to IL-1β exposure. NF-κB and C/EBP nuclear translocation was measured by Western blot and TransAMH after IL-1β (10 ng/ml) exposure. Results: No differences were observed in the MAPK phosphorylation time-course between NM and NP-AIA fibroblasts. The p38 MAPK inhibitor at 10 μM significantly reduced IL-1b-induced COX-2 expression in NM fibroblasts (85%). In NP-AIA fibroblasts the COX-2 inhibition (65%) at 1 and 10 μM was not statistically significant compared to non-treated cells. ERK and JNK inhibitors had no significant effect in either the NM or NP-AIA cultures. The effect of IL-1β on NF-κB and C/EBP subunits' nuclear translocation was similar between NM and NP-AIA fibroblasts. Conclusions: These results suggest that p38 MAPK is the only MAPK involved in IL-1β-induced COX-2 expression. NM and NP-AIA fibroblasts have similar MAPK phosphorylation dynamics and nuclear factor translocation (NF-κB and C/EBP). COX-2 downregulation observed in AIA patients appears not to be caused by differences in MAPK dynamics or transcription factor translocation. [ABSTRACT FROM AUTHOR]