Konermann Anna, Kantarci Alpdogan, Wilbert Steven, Van Dyke Thomas, Jäger Andreas
Department of Orthodontics, Medical Faculty, University of Bonn, Welschnonnenstr. 17, 53111, Bonn, Germany.
Forsyth Institute, 245 First St, Cambridge, MA, 02142, USA.
Cell Mol Neurobiol. 2016 Nov;36(8):1353-1363. doi: 10.1007/s10571-016-0335-6. Epub 2016 Feb 10.
CNS key neurotransmitter γ-amino-butyric acid (GABA) and its signaling components are likewise detectable in non-neuronal tissues displaying inter alia immunomodulatory functions. This study aimed at identifying potential glutamate decarboxylase (GAD)65 and GABA receptor expression in periodontal ligament (PDL) cells in vivo and in vitro, with particular regard to inflammation and mechanical loading. Gene expression was analyzed in human PDL cells at rest or in response to IL-1ß (5 ng/ml) or TNFα (5 ng/ml) challenge via qRT-PCR. Western blot determined constitutive receptor expression, and confocal laser scanning fluorescence microscopy visualized expression changes induced by inflammation. ELISA quantified GAD65 release. Immunocytochemistry was performed for GABA component detection in vitro on mechanically loaded PDL cells, and in vivo on rat upper jaw biopsies with mechanically induced root resorptions. Statistical significance was set at p < 0.05. GABA, GABA, GABA, and GABA were ubiquitously expressed both on gene and protein level. GABA and GAD65 were undetectable in resting cells, but induced by inflammation. GABA exhibited the highest basal gene expression (6.97 % ± 0.16). IL-1ß markedly increased GABA on a transcriptional (57.28-fold ± 12.40) and protein level seen via fluorescence microscopy. TNFα-stimulated PDL cells released GAD65 (3.68 pg/ml ± 0.17 after 24 h, 5.77 pg/ml ± 0.65 after 48 h). Immunocytochemistry revealed GAD65 expression in mechanically loaded PDL cells. In vivo, GABA components were varyingly expressed in an inflammatory periodontal environment. PDL cells differentially express GABA signaling components and secrete GAD65. Inflammation and mechanical loading regulate these neurotransmitter molecules, which are also detectable in vivo and are potentially involved in periodontal pathophysiology.
中枢神经系统关键神经递质γ-氨基丁酸（GABA）及其信号传导成分同样可在具有免疫调节功能等的非神经组织中检测到。本研究旨在鉴定体内和体外牙周膜（PDL）细胞中潜在的谷氨酸脱羧酶（GAD）65和GABA受体表达，尤其关注炎症和机械负荷。通过qRT-PCR分析静止或响应白细胞介素-1β（5 ng/ml）或肿瘤坏死因子α（5 ng/ml）刺激的人PDL细胞中的基因表达。蛋白质印迹法测定组成型受体表达，共聚焦激光扫描荧光显微镜观察炎症诱导的表达变化。酶联免疫吸附测定法量化GAD65释放。对机械加载的PDL细胞进行体外免疫细胞化学检测GABA成分，对机械诱导牙根吸收的大鼠上颌活检组织进行体内免疫细胞化学检测。统计学显著性设定为p < 0.05。GABA在基因和蛋白质水平均普遍表达。静止细胞中未检测到GABA和GAD65，但可由炎症诱导产生。GABA表现出最高的基础基因表达（6.97% ± 0.16）。白细胞介素-1β通过荧光显微镜观察到在转录水平（57.28倍 ± 12.40）和蛋白质水平显著增加GABA。肿瘤坏死因子α刺激的PDL细胞释放GAD65（24小时后为3.68 pg/ml ± 0.17，48小时后为5.77 pg/ml ± 0.65）。免疫细胞化学显示机械加载的PDL细胞中有GAD65表达。在体内，GABA成分在炎症性牙周环境中表达各异。PDL细胞差异表达GABA信号传导成分并分泌GAD65。炎症和机械负荷调节这些神经递质分子，它们在体内也可检测到，并可能参与牙周病理生理学过程。
