The alpha 7 nicotinic receptor agonist PHA-543613 hydrochloride inhibits Porphyromonas gingivalis-induced expression of interleukin-8 by oral keratinocytes

Macpherson, A., Zoheir, N., Awang, R. A., Culshaw, S. , Ramage, G. , Lappin, D. F. and Nile, C. J. (2014) The alpha 7 nicotinic receptor agonist PHA-543613 hydrochloride inhibits Porphyromonas gingivalis-induced expression of interleukin-8 by oral keratinocytes. Inflammation Research, 63(7), pp. 557-568. (doi: 10.1007/s00011-014-0725-5)

Abstract

Objective: The alpha 7 nicotinic receptor (α7nAChR) is expressed by oral keratinocytes. α7nAChR activation mediates anti-inflammatory responses. The objective of this study was to determine if α7nAChR activation inhibited pathogen-induced interleukin-8 (IL-8) expression by oral keratinocytes.<p></p> Materials and methods: Periodontal tissue expression of α7nAChR was determined by real-time PCR. OKF6/TERT-2 oral keratinocytes were exposed to <i>Porphyromonas gingivalis</i> in the presence and absence of a α7nAChR agonist (PHA-543613 hydrochloride) alone or after pre-exposure to a specific α7nAChR antagonist (α-bungarotoxin). Interleukin-8 (IL-8) expression was measured by ELISA and real-time PCR. Phosphorylation of the NF-κB p65 subunit was determined using an NF-κB p65 profiler assay and STAT-3 activation by STAT-3 in-cell ELISA. The release of ACh from oral keratinocytes in response to <i>P. gingivalis</i> lipopolysaccharide was determined using a GeneBLAzer M3 CHO-K1-blacell reporter assay.<p></p> Results: Expression of α7nAChR mRNA was elevated in diseased periodontal tissue. PHA-543613 hydrochloride inhibited <i>P. Gingivalis</i>-induced expression of IL-8 at the transcriptional level. This effect was abolished when cells were pre-exposed to a specific α7nAChR antagonist, α-bungarotoxin. PHA-543613 hydrochloride downregulated NF-κB signalling through reduced phosphorylation of the NF-κB p65-subunit. In addition, PHA-543613 hydrochloride promoted STAT-3 signalling by maintenance of phosphorylation. Furthermore, oral keratinocytes upregulated ACh release in response to <i>P. Gingivalis</i> lipopolysaccharide.<p></p> Conclusion: These data suggest that α7nAChR plays a role in regulating the innate immune responses of oral keratinocytes.<p></p>

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Lappin, Dr David and Ramage, Professor Gordon and Zoheir, Mrs Noha and Culshaw, Professor Shauna and Nile, Dr Christopher
• Authors: Macpherson, A., Zoheir, N., Awang, R. A., Culshaw, S., Ramage, G., Lappin, D. F., and Nile, C. J.
• College/School: College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing > Dental School
• Journal Name: Inflammation Research
• Publisher: Springer
• ISSN: 1023-3830
• ISSN (Online): 1420-908X
• Copyright Holders: Copyright © 2014 The Authors
• First Published: First published in Inflammation Research
• Publisher Policy: Reproduced under a Creative Commons License