Abstract
PDL cells express GABAB1 and GABAB2 receptors, which are regulated by inflammation and thus might be implicated in periodontal immunology. It was the aim of this study to elucidate the functional role of GABAB receptors in immunomodulation regarding activation of proregenerative versus proinflammatory mechanisms. Human PDL cells were exposed to GABA and/or GABAB receptor antagonist CGP-52432 alone or in combination with IL-1β to mimic inflammation. The influence on marker expression for inflammatory tissue destruction was determined via qRT-PCR and Luminex assays. Proliferation and biomineralization were assessed by MTS assay and von Kossa staining. Statistical significance was set at p < 0.05. GABAB receptor blockade inhibited expression of IL-6, TNFα, MMP-3, and MMP-8 in an inflammatory milieu on transcriptional and on protein level, mediated by NF-κB. Besides, receptor blockade enhanced proliferation, especially under inflammatory conditions, and reduced mineralization in a non-inflammatory milieu. GABAB receptor activity on PDL cells is involved in the modulation of osteoimmunological processes in the periodontium and decides on the initiation versus prevention of host protective mechanisms. This implies anabolic potential for a therapeutic preservation or reestablishment of periodontal tissues under physiological and pathological conditions. In summary, GABAB receptor modulation in PDL cells might become an important target in immunoinflammatory settings.
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Alhashimi N, Frithiof L, Brudvik P, Bakhiet M (2001) Orthodontic tooth movement and de novo synthesis of proinflammatory cytokines. Am J Orthod Dentofacial Orthop 119:307–312
Auteri M, Zizzo MG, Serio R (2015) GABA and GABA receptors in the gastrointestinal tract: from motility to inflammation. Pharmacol Res 93:11–21
Barragan A, Weidner JM, Jin Z, Korpi ER, Birnir B (2015) GABAergic signalling in the immune system. Acta Physiol (Oxf). 213:819–827
Basdra EK, Komposch G (1997) Osteoblast-like properties of human periodontal ligament cells: an in vitro analysis. Eur J Orthod 19:615–621
Bettler B, Tiao JY (2006) Molecular diversity, trafficking and subcellular localization of GABAB receptors. Pharmacol Ther 110:533–543
Franco R, Pacheco R, Lluis C, Ahern GP, O’Connell PJ (2007) The emergence of neurotransmitters as immune modulators. Trends Immunol 28:400–407
Jin Z, Mendu SK, Birnir B (2013) GABA is an effective immunomodulatory molecule. Amino Acids 45:87–94
Konermann A, Beyer M, Deschner J, Allam JP, Novak N, Winter J, Jepsen S, Jäger A (2012a) Human periodontal ligament cells facilitate leukocyte recruitment and are influenced in their immunomodulatory function by Th17 cytokine release. Cell Immunol 272:137–143
Konermann A, Deschner J, Allam JP, Novak N, Winter J, Baader SL, Jepsen S, Jäger A (2012b) Antigen-presenting cell marker expression and phagocytotic activity in periodontal ligament cells. J Oral Pathol Med 41:340–347
Konermann A, Götz W, Wohlleber D, Knolle P, Deschner J, Jäger A (2012c) Osteoimmunological mechanisms involved in orthodontically and bacterially induced periodontal stress. J Orofac Orthop 73:430–439
Konermann A, Stabenow D, Knolle PA, Held SA, Deschner J, Jäger A (2012d) Regulatory role of periodontal ligament fibroblasts for innate immune cell function and differentiation. Innate Immun 18:745–752
Konermann A, Kantarci A, Wilbert S, Van Dyke T, Jäger A (2016) Verification of γ-amino-butyric acid (GABA) signaling system components in periodontal ligament cells in vivo and in vitro. Cell Mol Neurobiol (Epub ahead of print)
Kook SH, Jang YS, Lee JC (2011) Human periodontal ligament fibroblasts stimulate osteoclastogenesis in response to compression force through TNF-α-mediated activation of CD4 + T cells. J Cell Biochem 112:2891–2901
Kuhn SA, van Landeghem FK, Zacharias R, Färber K, Rappert A, Pavlovic S, Hoffmann A, Nolte C, Kettenmann H (2004) Microglia express GABAB receptors to modulate interleukin release. Mol and Cell Neurosci 25:312–322
Kuhn SA, van Landeghem FK, Zacharias R, Färber K, Rappert A, Pavlovic S, Hoffmann A, Kumar PM, Reddy NR, Deepa A, Babu DS, Kumar AK, Chavan V (2013) Comparison of matrix metalloproteinase-3 and tissue inhibitor of matrix metalloproteinase-1 levels in gingival crevicular fluid in periodontal health, disease and after treatment: a clinico biochemical study. Dent Res J 10:434–439
Luk WP, Zhang Y, White TD, Lue FA, Wu C, Jiang CG, Zhang L, Moldofsky H (1999) Adenosine: a mediator of interleukin-1beta-induced hippocampal synaptic inhibition. J Neurosci 19:4238–4244
Moss SJ, Smart TG (1996) Modulation of amino acid-gated ion channels by protein phosphorylation. Int Rev Neurobiol 39:1–52
Olsen RW, Sieghart W (2008) International Union of Pharmacology. LXX. Subtypes of  -Aminobutyric AcidA Receptors: classification on the basis of subunit composition, pharmacology, and function update. Pharmacol Rev 60:243–260
Page RC (1991) The role of inflammatory mediators in the pathogenesis of periodontal disease. J Periodontal Res 26:230–242
Pfaffl MW (2001) A new mathematical model for relative quantification in real-time RT-PCR. Nucleic Acids Res 29:e45
Pringle AK, Gardner CR, Walker RJ (1996) Reduction of cerebellar GABAA responses by interleukin-1 (IL-1) through an indomethacin insensitive mechanism. Neuropharmacology 35:147–152
Sun C, Chen L, Shi X, Cao Z, Hu B, Yu W, Ren M, Hu R, Deng H (2016) Combined effects of proinflammatory cytokines and intermittent cyclic mechanical strain in inhibiting osteogenicity in human periodontal ligament cells. Cell Biol Int 40:999–1007
Thierbach R, Maier K, Sorsa T, Mäntylä P (2016) Peri-implant sulcus fluid (PISF) matrix metalloproteinase (MMP)-8 levels in peri-implantitis. J Clin Diagn Res 10:ZC34–ZC38
Tian J, Dang HN, Yong J, Chui WS, Dizon MP, Yaw CK, Kaufman DL (2011) Oral treatment with γ-aminobutyric acid improves glucose tolerance and insulin sensitivity by inhibiting inflammation in high fat diet-fed mice. PLoS ONE 6:e25338
Tian J, Dang H, Nguyen AV, Chen Z, Kaufman DL (2014) Combined therapy with GABA and proinsulin/alum acts synergistically to restore long-term normoglycemia by modulating T-cell autoimmunity and promoting β-cell replication in newly diabetic NOD mice. Diabetes 63:3128–3134
Vezzani A, Viviani B (2015) Neuromodulatory properties of inflammatory cytokines and their impact on neuronal excitability. Neuropharmacology 96(Pt A):70–82
Watanabe M, Maemura K, Kanbara K, Tamayama T, Hayasaki H (2002) GABA and GABA receptors in the central nervous system and other organs. Int Rev Cytol 213:1–47
Yan X, Jiang E, Weng HR (2015) Activation of toll like receptor 4 attenuates GABA synthesis and postsynaptic GABA receptor activities in the spinal dorsal horn via releasing interleukin-1 beta. J Neuroinflammation 12:222
Yucel-Lindberg T, Båge T (2013) Inflammatory mediators in the pathogenesis of periodontitis. Expert Rev Mol Med 15:e7
Acknowledgements
The authors would like to thank D. Nguyen and D. Stephens from the Forsyth Institute as much as K. Reifenrath and I. Bay-Müller from the Department of Orthodontics, University of Bonn for technical support. This research received Grant Support by the Deutsche Gesellschaft für Kieferorthopädie (DGKFO) and NIH/NIDCR Grant DE020906.
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Konermann, A., Van Dyke, T., Kantarci, A. et al. GABAB Receptors as Modulating Target for Inflammatory Responses of the Periodontal Ligament. Cell Mol Neurobiol 37, 1067–1076 (2017). https://doi.org/10.1007/s10571-016-0439-z
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DOI: https://doi.org/10.1007/s10571-016-0439-z