Department of Pediatric Dentistry, School of Stomatology, Fourth Military Medical University, Xi'an, Shaanxi, China ; Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi'an, Shaanxi, China.
Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi'an, Shaanxi, China ; Department of Oral Histology and Pathology, School of Stomatology, Fourth Military Medical University, Xi'an, Shaanxi, China.
PLoS One. 2013 Dec 20;8(12):e83102. doi: 10.1371/journal.pone.0083102. eCollection 2013.
Cigarette smoking is one of the high risk factors of adult chronic periodontitis and nicotine is the well established toxic substance in cigarette. However, the mechanism of nicotine induced periodontitis is still unknown. Here we studied whether nicotine impaired the osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs) through activating α7 nicotinic acetylcholine receptor (α7 nAChR).
hPDLSCs with multi differentiation potential and surface makers for mesenchymal stem cells were harvested by limiting dilution technique. The level of mineralized nodule formation was assessed by alizarin red S staining. Expression level of ostegenic related genes and proteins were detected by real-time PCR and western blot analysis. The expression of α7 nAChR and its downstream signaling pathway were examined by western blot. The role of the receptor and related signaling pathway in nicotine impairing the osteogenic potential of hPDLSCs were also studied in different levels.
Nicotine deteriorated the ostegenic differentiation of hPDLSCs in a dose dependent manner. Activation of α7 nAChR by nicotine treatment activated wnt/β-catenin signaling pathway, leading to osteogenic deficiency of hPDLSCs. Blockage of α7 nAChR and wnt pathway inhibitor treatment rescued nicotine induced osteogenic differentiation deficiency.
These data suggested that nicotine activated α7 nAChR expressed on PDLSCs and further activated wnt signaling downstream, thus deteriorating the osteogenic potential of PDLSCs. The impairment of osteogenic differentiation of PDLSCs by nicotine might lead to cigarette smoking related periodontitis.
吸烟是成人慢性牙周炎的高危因素之一，而尼古丁是香烟中已确定的有毒物质。然而，尼古丁诱导牙周炎的机制尚不清楚。在这里，我们研究了尼古丁是否通过激活α7 烟碱型乙酰胆碱受体（α7 nAChR）损害人牙周膜干细胞（hPDLSCs）的成骨分化。
采用有限稀释技术分离具有多向分化潜能和间充质干细胞表面标志物的 hPDLSCs。通过茜素红 S 染色评估矿化结节形成水平。实时 PCR 和 Western blot 分析检测成骨相关基因和蛋白的表达水平。Western blot 检测α7 nAChR 及其下游信号通路的表达。还在不同水平研究了受体和相关信号通路在尼古丁损害 hPDLSCs 成骨潜能中的作用。
尼古丁以剂量依赖的方式恶化 hPDLSCs 的成骨分化。尼古丁处理激活α7 nAChR 激活 wnt/β-catenin 信号通路，导致 hPDLSCs 成骨不足。阻断α7 nAChR 和 wnt 通路抑制剂治疗可挽救尼古丁诱导的成骨分化缺陷。
这些数据表明，尼古丁激活了 PDLSCs 上表达的α7 nAChR，并进一步激活了 wnt 信号下游，从而损害了 PDLSCs 的成骨潜能。尼古丁对 PDLSCs 成骨分化的损害可能导致与吸烟有关的牙周炎。
