Expression profiling and functional analysis of Toll-like receptors in primary healthy human nasal epithelial cells shows no correlation and a refractory LPS response. Issue 1 (December 2015)

• Record Type: Journal Article
• Authors: Tongeren, J.; Röschmann, K.; Reinartz, S.; Luiten, S.; Fokkens, W.; Jong, E.; Drunen, C.
• Is Part Of: Clinical and translational allergy. Volume 5:Issue 1(2015)
• Page Start: 1
• Page End: 9
• Publication Date: 2015-12
• Subjects: Nasal epithelial cells -- Pattern recognition receptors -- Toll-like receptor -- Chemokines -- Cytokines; Allergy -- Periodicals; Immunology -- Periodicals; Allergy and Immunology -- Periodicals; Hypersensitivity -- Periodicals; Immune System Phenomena -- Periodicals; 616.97005
• DOI: 10.1186/s13601-015-0086-3
• Languages: English
• ISSNs: 2045-7022

Abstract

Abstract Background Innate immune recognition via Toll-like receptors (TLRs) on barrier cells like epithelial cells has been shown to influence the regulation of local immune responses. Here we determine expression level variations and functionality of TLRs in nasal epithelial cells from healthy donors. Methods Expression levels of the different TLRs on primary nasal epithelial cells from healthy donors derived from inferior turbinates was determined by RT-PCR. Functionality of the TLRs was determined by stimulation with the respective ligand and evaluation of released mediators by Luminex ELISA. Results Primary nasal epithelial cells express different levels of TLR1-6 and TLR9. We were unable to detect mRNA of TLR7, TLR8 and TLR10. Stimulation with Poly(I:C) resulted in a significant increased secretion of IL-4, IL-6, RANTES, IP-10, MIP-1β, VEGF, FGF, IL-1RA, IL-2R and G-CSF. Stimulation with PGN only resulted in significant increased production of IL-6, VEGF and IL-1RA. Although the expression of TLR4 and co-stimulatory molecules could be confirmed, primary nasal epithelial cells appeared to be unresponsive to stimulation with LPS. Furthermore, we observed huge individual differences in TLR agonist-induced mediator release, which did not correlate with the respective expression of TLRs. Conclusion Our data suggest that nasal epithelium seems to have developed a delicate system of discrimination and recognition of microbial patterns. Hypo-responsiveness to LPS could provide a mechanism to dampen the inflammatory response in the nasal mucosa in order to avoid a chronic inflammatory response. Individual, differential expression of TLRs on epithelial cells and functionality in terms of released mediators might be a crucial factor in explaining why some people develop allergies to common inhaled antigens, and others do not.