Sema3A/Nrp1信号轴的骨保护效应在根尖周炎中的作用与机制研究

Recent studies showed that Sema3A and its receptor Nrp1 exert osteoprotective effects through suppressing osteoclastic differentiation and promoting osteoblastic differentiation. The Sema3A /Nrp1 signal axis also regulates immune response of T cells.The Sema3A /Nrp1 signal axis seams to be a promising new therapeutic agent in inflammation-induced bone resorption diseases. Our pilot data exhibited that lipopolysaccharide from Porphyromonas gingivalis reduced the expression of Sema3A /Nrp1 signal axis in murine osteoblasts. In this study, the expression of Sema3A /Nrp1 signal axis will be observed in the periapical lesions of animal models and the patients' samples on the different periods. The change of periapical bone loss will be accessed in animal model by the intervention of Sema3A /Nrp1 signal axis. The expression of Sema3A /Nrp1 signal axis will be investigated in the periapical tissue cells. To further analyse the expression of Sema3A /Nrp1 signal axis and the dependent signal transduction pathway in the periapical tissue cells in the inflammatory microenvironment.The osteoblasts and CD4+T cells co-culture system will be used to study the role of Sema3A/Nrp1 signal axis on the osteoblasts mediated immune regulation of CD4+T cell both in regular and inflammatory microenvironment. This study will help to discover the fundamental role of Sema3A/Nrp1 signal axis in bone loss of periapical periodontitis.This proposal will provide novel cues and clues for the mechanism and treatment of bone loss that is associated with periapical periodontitis and other inflammation-induced bone resorption diseases.

最新研究发现轴突导向蛋白Sema3A及其受体 Nrp1，具有促进成骨细胞分化成熟和抑制破骨细胞分化的双重调节作用。此外，还参与T细胞的免疫调控，可能成为治疗炎症性骨吸收的新方法。本课题组预实验发现牙龈卟啉单胞菌的脂多糖抑制Sema3A/Nrp1信号轴在小鼠成骨细胞的表达。本研究拟观察Sema3A/Nrp1信号轴在动物根尖周炎的模型和人体根尖周炎病变组织中的表达与定位；干预Sema3A/Nrp1信号轴，观察局部骨破坏和炎症的改变情况；研究炎症微环境对Sema3A/Nrp1信号轴在根尖周组织相关细胞表达的影响和可能依赖的信号转导通路；建立成骨细胞与CD4+T细胞共培养体系，研究Sema3A/Nrp1信号轴介导的免疫调控作用，以及炎症微环境对其的影响。以期阐明Sema3A/Nrp1信号轴在根尖周炎骨破坏中可能的作用机制，为揭示根尖周炎骨破坏以及炎症性骨破坏的发病机制和治疗提供新的思路和科学依据。

以往的研究发现轴突导向蛋白Sema3A 及其受体Nrp1，具有促进成骨细胞分化成熟和抑制破骨细胞分化的双重调节作用。此外，还参与T 细胞的免疫调控，可能成为治疗炎症性骨吸收的新方法。我们通过构建动物根尖周炎的模型本，并采集临床标本，研究观察Sema3A/Nrp1 信号轴在动物根尖周炎的模型和采集人体根尖周炎病变组织中的表达与定位。结果表明Sema3A/Nrp1在根尖周炎病变组织中,Sema3A/Nrp1阳性细胞数要明显低于对照组，根尖病变区域的Sema3A/Nrp1的mRNA表达水平也明显低于对照组。Sema3A/Nrp1的表达在病变区域与骨破坏的程度和破骨细胞数呈明显的负相关。免疫组化，免疫荧光和Realtime-PCR的结果表明Sema3A/Nrp1在人的根尖周病变组织中的表达也低于对照组。此外，本课题组研究还对对炎症微环境对Sema3A/Nrp1 信号轴在根尖周组织相关细胞表达的影响进行研究。研究结果表明牙龈卟啉单胞菌的脂多糖抑制Sema3A/Nrp1 信号轴在小鼠成骨前体细胞表达，降低Nrp1在破骨前体细胞的表达。综上所述，本项目研究提示Sema3A/Nrp1信号轴的表达与根尖周炎的发生发展以及炎症性骨破坏有一定的相关性，呈明显的负相关。本课题所获得的研究结果为揭示根尖周炎骨破坏以及炎症性骨破坏的发病机制和治疗提供新的思路和科学依据。