Wang Liping, Zheng Jing, Pathak Janak L, Chen Yunxin, Liang Dongliang, Yang Luxi, Sun Haobo, Zhong Mei, Wu Lihong, Li Li, Deng Shuhua, Zheng Lingyun, Yan Yongyong, Hou Dan, Wang Lijing, Ge Linhu
Guangzhou Key Laboratory of Basic and Applied Research in Oral Regenerative Medicine, Affiliated Stomatology Hospital of Guangzhou Medical University, Institute of Oral Disease, Guangzhou Medical University, Guangzhou, China.
Vascular Biology Research Institute, School of Life Sciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, China.
Front Cell Dev Biol. 2020 Jul 14;8:593. doi: 10.3389/fcell.2020.00593. eCollection 2020.
SLIT2, a member of neuronal guidance cues, has been reported to regulate inflammation and cancer progression. Periodontitis is an oral inflammatory disease that degenerates periodontal tissue, alveolar bone and tooth. This study aims to explore the expression pattern of SLIT2 in periodontitis and its role in disease progression and bone loss. Gingival tissue of 20 periodontitis patients and 20 healthy-controls was obtained. Ligature-induced periodontitis (LIP) mice-model was developed in and wild-type mice. The effect of SLIT2 on inflammation, immune cell infiltration, M1 macrophage polarization, and alveolar bone loss in periodontitis was analyzed extensively. In periodontitis-affected gingival-tissue, SLIT2 expression was 4.4-fold higher compared to healthy-volunteers. LIP enhanced SLIT2 expression in mice periodontitis-affected periodontal tissue (PAPT) and blood circulation of wild-type mice by 4. 6-, and 5.0-fold, respectively. In Slit2-Tg-mice PAPT, SLIT2 expression was 1.8-fold higher compared to wild-type mice. Micro-CT and histomorphometric analysis revealed a 1.3-fold higher cement-enamel-junction to the alveolar-bone-crest (CEJ-ABC) distance and alveolar bone loss in LIP Slit2-Tg-mice compare to LIP wild-type mice. Results from RNA-sequencing, RT-qPCR, and ELISA showed a higher expression of Cxcr2, Il-18, TNFα, IL-6, and IL-1β in Slit2-Tg-mice PAPT compared to wild-type-mice. Slit2-Tg-mice PAPT showed a higher number of osteoclasts, M1 macrophages, and the upregulation of Robo1 expression. Slit2-Tg-mice PAPT showed upregulation of M1 macrophage marker CD16/32 and osteoclastogenic markers , , and , but osteogenic markers () remained unchanged. Immunohistochemistry unveiled the higher vasculature and infiltration of leucocytes and macrophages in Slit2-Tg-mice PAPT. RNA-sequencing, GO-pathway enrichment analysis, and western blot analysis revealed the activation of the MAPK signaling pathway in -Tg mice PAPT. In conclusion, SLIT2 overexpression in periodontitis intensifies inflammation, immune cells infiltration, M1 macrophage polarization, osteoclastogenesis, and alveolar bone loss, possibly via activation of MAPK signaling, suggesting the role of SLIT2 on exacerbation of periodontitis and alveolar bone loss.
SLIT2是神经导向因子的一员，据报道可调节炎症和癌症进展。牙周炎是一种使牙周组织、牙槽骨和牙齿退化的口腔炎症性疾病。本研究旨在探讨SLIT2在牙周炎中的表达模式及其在疾病进展和骨质流失中的作用。获取了20名牙周炎患者和20名健康对照者的牙龈组织。在野生型小鼠中建立了结扎诱导性牙周炎（LIP）小鼠模型。广泛分析了SLIT2对牙周炎中炎症、免疫细胞浸润、M1巨噬细胞极化和牙槽骨流失的影响。在受牙周炎影响的牙龈组织中，SLIT2表达比健康志愿者高4.4倍。LIP使野生型小鼠牙周炎受累牙周组织（PAPT）中的SLIT2表达和血液循环分别增强了4.6倍和5.0倍。在Slit2转基因小鼠的PAPT中，SLIT2表达比野生型小鼠高1.8倍。显微CT和组织形态计量分析显示，与LIP野生型小鼠相比，LIP Slit2转基因小鼠的牙骨质釉质界至牙槽嵴顶（CEJ-ABC）距离和牙槽骨流失高1.3倍。RNA测序、RT-qPCR和ELISA结果显示，与野生型小鼠相比，Slit2转基因小鼠的PAPT中Cxcr2、Il-18、TNFα、IL-6和IL-1β表达更高。Slit2转基因小鼠的PAPT显示破骨细胞、M1巨噬细胞数量更多，Robo1表达上调。Slit2转基因小鼠的PAPT显示M1巨噬细胞标志物CD16/32和成骨细胞生成标志物、和上调，但成骨标志物（）保持不变。免疫组织化学显示，Slit2转基因小鼠的PAPT中血管分布更多，白细胞和巨噬细胞浸润更多。RNA测序、GO通路富集分析和蛋白质印迹分析显示，转基因小鼠的PAPT中MAPK信号通路被激活。总之，牙周炎中SLIT2过表达会加剧炎症、免疫细胞浸润、M1巨噬细胞极化、破骨细胞生成和牙槽骨流失，可能是通过激活MAPK信号通路，提示SLIT2在牙周炎和牙槽骨流失加重中所起的作用。
