Institute for Genome Research, Tokushima University, Tokushima, Japan.
Department of Periodontology and Endodontology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
J Cell Biochem. 2018 Feb;119(2):1591-1603. doi: 10.1002/jcb.26319. Epub 2017 Sep 7.
Accumulation of advanced glycation end-products (AGEs) in periodontal tissues of patients with diabetes mellitus aggravates periodontitis, but the mechanisms are unknown. Calprotectin, a heterocomplex of S100A8 and S100A9 proteins, is a constitutive cytoplasmic component of healthy gingival epithelial cells. This study aimed at investigating the effects of AGE and Porphyromonas gingivalis lipopolysaccharide (PgLPS) on calprotectin expression in the human gingival epithelial cell line OBA-9. AGE and PgLPS increased the expression of S100A8 and S100A9 mRNAs, and AGE+PgLPS co-stimulation amplified their expression in OBA-9 cells. A higher concentration of calprotectin in cell lysates was also induced by stimulation with AGE and/or PgLPS. S100A8 was mainly translocated from the nucleus to the cytoplasm by AGE stimulation, while cytoplasmic localization of S100A9 was not altered following stimulation with AGE and/or PgLPS. Calprotectin was found in the cytoplasm of BSA-treated cells, but cytoplasmic and nuclear localization was observed following stimulation with AGE and/or PgLPS. AGE-induced S100A8, and S100A9 mRNA expression was partially suppressed by RAGE-specific siRNA. In contrast, PgLPS-induced S100A8 and S100A9 mRNA expression was strongly suppressed by TLR2-specific siRNA. Furthermore, the inhibition of p38, JNK MAPK, and NF-κB attenuated AGE- and PgLPS-induced S100A8 and S100A9 mRNA expression. Taken together, these results demonstrate that AGE acts in synergy with PgLPS to stimulate RAGE and TLR2 expression and activate p38, JNK MAPK, and NF-κB signaling pathways, resulting in increased activation of calprotectin (S100A8/S100A9) in human gingival epithelial cells. Our results suggest that calprotectin may be involved in the pathogenesis of diabetic periodontitis.
糖尿病患者牙周组织中晚期糖基化终产物（AGEs）的积累加重了牙周炎，但机制尚不清楚。钙卫蛋白是 S100A8 和 S100A9 蛋白的异源复合物，是健康牙龈上皮细胞的固有细胞质成分。本研究旨在探讨 AGE 和牙龈卟啉单胞菌脂多糖（PgLPS）对人牙龈上皮细胞系 OBA-9 中钙卫蛋白表达的影响。AGE 和 PgLPS 增加了 S100A8 和 S100A9 mRNA 的表达，AGE+PgLPS 共同刺激增强了 OBA-9 细胞中它们的表达。刺激物 AGE 和/或 PgLPS 还诱导细胞裂解物中钙卫蛋白的浓度升高。AGE 刺激主要将 S100A8 从核转位到细胞质，而 AGE 和/或 PgLPS 刺激后 S100A9 的细胞质定位没有改变。BSA 处理的细胞中发现钙卫蛋白存在于细胞质中，但刺激 AGE 和/或 PgLPS 后观察到细胞质和核定位。AGE 诱导的 S100A8 和 S100A9 mRNA 表达被 RAGE 特异性 siRNA 部分抑制。相反，TLR2 特异性 siRNA 强烈抑制 PgLPS 诱导的 S100A8 和 S100A9 mRNA 表达。此外，p38、JNK MAPK 和 NF-κB 的抑制减弱了 AGE 和 PgLPS 诱导的 S100A8 和 S100A9 mRNA 表达。综上所述，这些结果表明，AGE 与 PgLPS 协同作用刺激 RAGE 和 TLR2 表达，并激活 p38、JNK MAPK 和 NF-κB 信号通路，导致人牙龈上皮细胞中钙卫蛋白（S100A8/S100A9）的激活增加。我们的结果表明，钙卫蛋白可能参与糖尿病牙周炎的发病机制。
