Altering Cytokine mRNA Stability in Periodontal Bone Loss

描述(由申请人提供)：牙周病的发生和发展是宿主对口腔病原体的免疫炎症反应的结果。炎症细胞因子的产生是一个高度调控的过程，涉及转录和转录后机制。在转录后水平，包括IL-6、肿瘤坏死因子-α和环氧合酶-2在内的许多细胞因子基因3‘非翻译区的腺苷/尿苷富含元件(Ares)的存在，使信使核糖核酸快速降解。结果，细胞因子的产生受到抑制。Tristetraprolin(TTP)是一种锌指蛋白，能与细胞因子mRNAs结合，促进mRNAs的降解。TTP被p38-MK2途径磷酸化，可能是细胞因子mRNA调控的一般机制。我们最近发现，内毒素诱导的IL-6mRNA的稳定表达需要p38信号。初步数据表明，TTP转基因细胞可抑制脂多糖诱导的IL-6表达。基于这些数据，我们假设TTP的mRNA衰变增强特性可能被开发用于潜在的抗炎目的。在这项建议中，TTP过表达减轻炎症的能力将在体外使用巨噬细胞中的基因靶向策略来确定，并在体内使用实验性牙周炎模型来确定。其具体目的是1)阐明TTP在体外对IL-6、TNF和COX-2mRNA表达及稳定性的影响；2)利用TTP-/-小鼠确定TTP在炎症和牙周病原体引发的体内骨破坏中的作用。这些研究将通过以TTP为靶点的选择性信使核糖核酸降解，确定内毒素诱导的细胞因子信使核糖核酸在炎症性骨丢失中的作用。随着这些目标的实现，后续的研究将探讨TTP作为一种治疗策略在小动物模型中控制牙周骨丢失的潜力。牙周病的发生和发展是宿主对口腔病原体的免疫炎症反应的结果。这些研究将通过选择性地以调节细胞因子mRNA稳定性的蛋白质为靶点，来确定宿主免疫蛋白(称为细胞因子)在炎症性骨丢失中的作用以及细胞因子在mRNA稳定性水平上的调节作用。了解转录后细胞因子调控在牙周炎和骨丢失中的作用的进展可能为牙周病和其他慢性炎症性疾病的治疗提供新的可能性。

DESCRIPTION (provided by applicant): Periodontal disease initiation and progression occurs as a consequence of the host immune inflammatory response to oral pathogens. The production of inflammatory cytokines is a highly regulated process involving transcriptional and posttranscriptional mechanisms. At the posttranscriptional level, the presence of adenosine/uridine-rich elements (AREs) in the 3' untranslated region of many cytokine genes, including IL-6, TNF-a, and COX-2, targets the mRNA for rapid degradation. As a consequence, cytokine production is repressed. Tristetraprolin (TTP) is a zinc finger protein that binds to the ARE of cytokine mRNAs and enhances degradation of the mRNA. TTP is phosphorylated by the p38-MK2 pathway and may serve as a general mechanism of cytokine mRNA regulation. We have recently shown that LPS-induced IL-6 mRNA stability expression requires p38 signaling. Preliminary data for this proposal indicates that TTP transfected cells inhibit LPS-induced IL-6 expression. Based upon these data, we hypothesize that the mRNA decay enhancing properties of TTP may be exploited for potential anti-inflammatory purposes. In this proposal, the ability of TTP over-expression to decrease inflammation will be determined in vitro using gene targeted strategies in macrophages, and in vivo using experimental periodontitis models. The specific aims are 1) to clarify the role of TTP on IL-6, TNF, and COX-2 mRNA expression and stability in vitro and 2) determine the impact of TTP in inflammatory and periodontal pathogen- initiated bone destruction in vivo using TTP-/- mice. These studies will establish the role of LPS-induced cytokine mRNA stability in inflammatory bone loss through selective mRNA decay targeting with TTP. Upon the accomplishment of these aims, subsequent studies will address the potential of TTP as a therapeutic strategy to control periodontal bone loss in small animal models. Periodontal disease initiation and progression occurs as a consequence of the host immune inflammatory response to oral pathogens. These studies will establish the role of host immune proteins termed cytokines and the regulation of cytokines at the level of mRNA stability in inflammatory bone loss through selective mRNA decay targeting with a protein that regulates cytokine mRNA stability. Progress in understanding the role of posttranscriptional cytokine regulation in periodontal inflammation and bone loss may yield new possibilities for treatment of periodontal diseases and other chronic inflammatory diseases.