Department of Periodontology, Division of Oral Biology and Disease Control, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan.
Arch Oral Biol. 2012 May;57(5):483-90. doi: 10.1016/j.archoralbio.2011.10.007. Epub 2011 Nov 25.
Cigarette smoking is an important risk factor for periodontal disease. The aim of this study is to evaluate the effect of nicotine, a major component of cigarette smoke, on interleukin-8 (IL-8) production and cellular signalling via nicotinic acetylcholine receptors (nAChRs) in human gingival epithelial cells (HGECs).
Messenger RNA (mRNA) expression of nAChR subunits in three different HGEC lines (epi 4, Tfx and E6E7) was assessed using reverse transcription-polymerase chain reaction (RT-PCR). HGECs were stimulated by 1×10(-3)M nicotine in the presence or absence of IL-1β or Porphyromonas gingivalis lipopolysaccharide (LPS). IL-8 production was then examined using real-time PCR and enzyme-linked immunosorbent assay. Nicotine-mediated signalling in the epi 4 cell line was also evaluated by Western blotting.
HGECs expressed several nAChR subunits. Nicotine increased the secretion of IL-8 from HGECs that were cultured in the presence of IL-1β or P. gingivalis LPS and also induced the phosphorylation of extracellular signal-regulated kinase (ERK) in epi 4. Pretreatment with non-selective nAChR antagonist or intracellular calcium chelator reduced the nicotine-induced phosphorylation of ERK. Furthermore, nicotine-induced IL-8 secretion was decreased by pretreatment with non-selective nAChR antagonist, ERK1/2 inhibitor or intracellular calcium chelator.
These findings indicate that nicotine increases IL-8 production in gingival epithelial cells via ERK phosphorylation following Ca(2+) signalling after nAChR activation.
吸烟是牙周病的一个重要危险因素。本研究旨在评估香烟烟雾的主要成分尼古丁通过烟碱型乙酰胆碱受体（nAChR）对人牙龈上皮细胞（HGEC）中白细胞介素-8（IL-8）的产生和细胞信号转导的影响。
使用逆转录聚合酶链反应（RT-PCR）评估三种不同 HGEC 系（epi 4、Tfx 和 E6E7）中 nAChR 亚单位的信使 RNA（mRNA）表达。用 1×10（-3）M 尼古丁刺激 HGEC，同时存在或不存在白细胞介素-1β或牙龈卟啉单胞菌脂多糖（LPS）。然后使用实时 PCR 和酶联免疫吸附试验检测 IL-8 的产生。还通过 Western blot 评估 epi 4 细胞系中尼古丁介导的信号转导。
HGEC 表达多种 nAChR 亚单位。尼古丁增加了在存在白细胞介素-1β或牙龈卟啉单胞菌 LPS 的情况下培养的 HGEC 中 IL-8 的分泌，并诱导 epi 4 中细胞外信号调节激酶（ERK）的磷酸化。用非选择性 nAChR 拮抗剂或细胞内钙螯合剂预处理可降低尼古丁诱导的 ERK 磷酸化。此外，用非选择性 nAChR 拮抗剂、ERK1/2 抑制剂或细胞内钙螯合剂预处理可减少尼古丁诱导的 IL-8 分泌。
这些发现表明，尼古丁通过 nAChR 激活后的 Ca（2+）信号转导，增加 ERK 磷酸化，从而增加牙龈上皮细胞中 IL-8 的产生。
