Research Unit for Oral-Systemic Connection, Division of Oral Science for Health Promotion, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan; Division of Periodontology, Department of Oral Biological Science, Niigata University Faculty of Dentistry, Niigata, Japan.
Division of Periodontology, Department of Oral Biological Science, Niigata University Faculty of Dentistry, Niigata, Japan.
Arch Oral Biol. 2020 Feb;110:104602. doi: 10.1016/j.archoralbio.2019.104602. Epub 2019 Nov 5.
Oxidative stress, which is defined as an imbalance between pro-oxidant and antioxidant systems, has been implicated in the development and/or progression of several inflammatory diseases, including periodontal disease. The reactive oxygen species (ROS) are the primary inducers of oxidative stress. In the induction of cytoprotective enzymes, the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) signaling in antioxidant systems takes a main role. Notably, 10-oxo-trans-11-octadecenoic acid (KetoC), known as a bioactive metabolite generated by intestinal microorganisms, has been reported to have beneficial effects on several biological responses. Therefore, we investigated the antioxidant effect of KetoC on gingival epithelial cells (GECs) in this present study.
An SV40-T antigen-transformed human gingival epithelial cell line (Epi4) was used for experiments. The alteration of anti-oxidative stress related genes was analyzed by qPCR. The cellular ROS levels were evaluated by flow cytometry. To explore its molecular mechanisms, ARE promotor activity was analyzed by luciferase assay; the involvement of mitogen-activated protein kinase (MAPK) and G protein-coupled receptor 120 (GPR120) were evaluated by Western blotting and luciferase assay, respectively.
KetoC significantly increased the expression of antioxidant-related genes in GECs. The level of ROS was significantly inhibited by the pretreatment of KetoC. Extracellular signal-regulated kinase (ERK) phosphorylation by KetoC promoted both the nuclear translocation of Nrf2 and its binding to the ARE in GECs. Further, GPR120 regulated the activation of KetoC induced-Nrf2-ARE signaling.
KetoC exerts a protective function against the oxidative stress in GECs through GPR120-dependent ERK-Nrf2-ARE signaling.
氧化应激被定义为促氧化剂和抗氧化系统之间的失衡，与几种炎症性疾病的发展和/或进展有关，包括牙周病。活性氧（ROS）是氧化应激的主要诱导剂。在细胞保护酶的诱导中，抗氧化系统中的核因子红细胞 2 相关因子 2（Nrf2）/抗氧化反应元件（ARE）信号转导起着主要作用。值得注意的是，10-氧代-trans-11-十八碳烯酸（KetoC），作为一种由肠道微生物产生的生物活性代谢物，已被报道对几种生物学反应具有有益的影响。因此，本研究旨在探讨 KetoC 对牙龈上皮细胞（GECs）的抗氧化作用。
本研究采用 SV40-T 抗原转化的人牙龈上皮细胞系（Epi4）进行实验。通过 qPCR 分析抗氧化应激相关基因的变化。通过流式细胞术评估细胞内 ROS 水平。为了探讨其分子机制，通过荧光素酶测定分析 ARE 启动子活性；通过 Western blot 和荧光素酶测定分别评估丝裂原活化蛋白激酶（MAPK）和 G 蛋白偶联受体 120（GPR120）的参与。
KetoC 显著增加了 GECs 中抗氧化相关基因的表达。KetoC 的预处理显著抑制了 ROS 水平。KetoC 通过细胞外信号调节激酶（ERK）磷酸化促进 Nrf2 的核易位及其与 GECs 中 ARE 的结合。此外，GPR120 调节 KetoC 诱导的 Nrf2-ARE 信号的激活。
KetoC 通过 GPR120 依赖性 ERK-Nrf2-ARE 信号转导对 GECs 中的氧化应激发挥保护作用。
