Altering Cytokine mRNA Stability in Periodontal Bone Loss

描述（由申请方提供）：牙周病的发生和进展是宿主对口腔病原体的免疫炎症反应的结果。炎性细胞因子的产生是一个涉及转录和转录后机制的高度调节的过程。在转录后水平，在许多细胞因子基因（包括IL-6、TNF-α和考克斯-2）的3'非翻译区中存在腺苷/尿苷富集元件（战神），靶向mRNA以快速降解。因此，细胞因子的产生受到抑制。Tristetraprolin（TTP）是一种锌指蛋白，其与细胞因子mRNA的ARE结合并增强mRNA的降解。TTP通过p38-MK2途径被磷酸化，并且可能作为细胞因子mRNA调节的一般机制。我们最近发现LPS诱导的IL-6 mRNA稳定表达需要p38信号。该提议的初步数据表明，TTP转染的细胞抑制LPS诱导的IL-6表达。基于这些数据，我们假设TTP的mRNA衰变增强特性可用于潜在的抗炎目的。在该提议中，TTP过表达减少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，并且在体内使用实验性牙周炎模型来确定。具体目的是1）阐明TTP对IL-6、TNF和考克斯-2 mRNA表达和体外稳定性的作用和2）使用TTP-/-小鼠确定TTP在体内炎症和牙周病原体引发的骨破坏中的影响。这些研究将通过以TTP为靶点的选择性mRNA衰减来确定LPS诱导的细胞因子mRNA稳定性在炎性骨丢失中的作用。在实现这些目标后，后续研究将探讨TTP作为小动物模型中控制牙周骨丢失的治疗策略的潜力。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。这些研究将确定称为细胞因子的宿主免疫蛋白的作用，以及通过选择性mRNA衰减靶向调节细胞因子mRNA稳定性的蛋白质，在炎症性骨丢失中在mRNA稳定性水平上调节细胞因子。了解转录后细胞因子调控在牙周炎症和骨丢失中的作用的进展可能为牙周疾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.