Treatment of periodontitis by homing M2 macrophages

项目总结 牙周炎是第二种最常见的口腔疾病，影响着美国大约一半的成年人(6500万人) 各州。牙周炎会导致牙齿脱落，并与几种严重的系统性疾病有关，包括 糖尿病、心血管疾病和早产儿。牙周炎是一种慢性炎症， 由牙菌斑和牙石中的细菌感染引发，但疾病本身是由宿主引起的 对这些病原体的免疫反应。目前的标准治疗方法是清除斑块和结石以 减少细菌负荷，然而，没有治疗方法来解决疾病的免疫方面。 因此，许多研究小组已经开始开发技术来调节免疫反应和 减少炎症。到目前为止，我们的团队一直专注于招募T调节性免疫细胞作为新的靶点 牙周炎的治疗。 在之前的研究中，我们通过在牙槽骨中招募调节性T细胞成功地减少了牙槽骨的丢失 小鼠和狗牙周炎模型。通过注射C-C基序趋化因子22来招募调节性T细胞 (CCL22)在牙周袋中释放PLGA微粒。这些结果表明，招聘 局部递送趋化因子的调节性免疫细胞确实减少了炎症和骨丢失 牙周炎。 进一步探讨“招募调节性免疫细胞”的原则，并继续努力 开发更好的治疗方法，我们假设招募更多的抗炎免疫细胞 如M2巨噬细胞将实现更好的治疗选择。巨噬细胞在 炎症反应，有趣的是，通过分化为M1(亲- 炎性)或M2(抗炎)巨噬细胞。我们的假设得到了我们最近的 体内试验数据表明，局部递送CCL2将诱导M2巨噬细胞归巢，并且 巨噬细胞和单核细胞分化为M2表型导致炎症减轻 以及牙周组织中的骨丢失。为了验证这一假设，我们设定了以下具体目标：1) CCL2释放微粒的制备及M2巨噬细胞募集和分化分析 巨噬细胞和单核细胞对M2巨噬细胞的影响2)分析CCL2对小鼠牙周炎的影响 模特。 我们预计PLGA微粒释放的CCL2会募集和诱导M2巨噬细胞，并且 减轻小鼠牙周炎模型牙周组织炎症和骨丢失。而且，这个概念， 可用于其他炎症性疾病的治疗，如糖尿病伤口愈合延迟或 肠病。

PROJECT SUMMARY Periodontitis is the second most common oral disease, affecting about half of adults (65 millions) in the United States. Periodontitis causes tooth loss and has been implicated in several serious systemic diseases include diabetes, cardiovascular diseases, and immature birth. Periodontitis is a chronic inflammatory disease, triggered by bacterial infection present in dental plaques and calculus, but the disease itself is caused by host immune response to these pathogens. Current standard treatment is debridement of plaques and calculus to reduce the bacterial load, however, there are no therapies to address the immune aspect of the diseases. Thus, many research groups have started developing technologies to regulate the immune response and reduce inflammation. Our group has focused so far on recruiting T regulatory immune cells new target for therapy of periodontitis. In the previous study, we have successfully reduced alveolar bone loss by recruiting regulatory T cells in mouse and dog periodontitis model. Regulatory T cells were recruited by injecting C-C motif chemokine 22 (CCL22) releasing PLGA microparticles in the periodontal pockets. These results indicated that recruiting regulatory immune cells by local delivery of chemokine indeed reduces inflammation and bone loss in periodontitis. To further explore the principle of “recruitment of regulatory immune cells” and to continue our efforts to develop better therapies, we hypothesize that recruiting a larger population of anti-inflammatory immune cells such as M2 macrophages will achieve a better therapeutic option. Macrophages plays an important role in inflammatory responses, and interestingly have a polarization property by differentiating into M1 (pro- inflammatory) or M2 (anti-inflammatory) macrophages. Our hypothesis that is strongly supported by our recent in vivo pilot data is that the local delivery of CCL2 will induce homing of M2 macrophages, and differentiation of macrophages and monocytes to an M2 phenotype leading to decreased inflammation and bone loss in periodontal tissue. To test this hypothesis, we set the following specific aims; 1) To fabricate CCL2 releasing microparticles and analyze recruitment of M2 macrophage and differentiation of macrophages and monocytes to M2 macrophages and 2) To analyze effect of CCL2 on periodontitis in mouse model. We anticipate that CCL2 released from PLGA microparticles will recruit and induce M2 macrophages, and reduce inflammation and bone loss of periodontal tissue in mouse periodontitis model. Moreover, this concept could be applied to therapies for other inflammatory diseases such as delayed wound healing of diabetes or bowel disease.