Negative Regulation of Innate Immune Responses through MAPK Phosphatases

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。p38 MARK中由周围病原性LPS激活的主要信号通路之一。在p38磷酸化之后，p38 MAP激酶的失活主要通过双特异性MAP激酶磷酸酶（MKP）家族实现。MKP-1能够负调节转录和转录后p38 MAP激酶活性。MKP-1有助于LPS耐受性，并且MKP-1的过表达已显示加速p38失活，导致促炎细胞因子产生减少。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，在MKP- 1转染的细胞中，LPS诱导的IL-6表达显著减弱。此外，我们提供了重要的数据表明，p38是一个主要的信号通路，有助于LPS诱导的牙周骨破坏。基于这些数据，我们假设p38信号传导的内源性负调节机制MKP-1是负责减弱LPS诱导的巨噬细胞中炎性细胞因子表达的关键组分。在该提议中，TIP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）在体外确定过表达的MKP-1对IL-6和TNF α mRNA表达的作用。2)确定MKP-1在原代骨髓巨噬细胞中炎性细胞因子产生和LPS诱导的破骨细胞生成的个体发生中的作用，以及3）使用MKP小鼠确定MKP-1在体内炎性骨破坏中的影响。这些研究将通过选择性减弱牙周骨破坏中p38 MAPK诱导的信号传导，确定LPS诱导的细胞因子表达和负调控在炎症性骨丢失中的作用。

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. One of the major signaling pathways activated by periopathogenic LPS in p38 MARK. Following p38 phosphorylation, inactivation of p38 MAP kinases is achieved mainly by a family of dual-specific MAP kinase phosphatases (MKP). MKP-1 is capable of negatively regulating both transcriptional and post transcriptional p38 MAP kinase activity. MKP-1 contributes towards LPS tolerance and over-expression of MKP-1 has shown to accelerate p38 inactivation resulting in diminished proinflammatory cytokine production. We have recently shown that LPS-induced IL-6 mRNA stability expression requires p38 signaling. Preliminary data for this proposal indicates that in MKP- 1 transfected cells, LPS-induced IL-6 expression is significantly attenuated. In addition, we have provided significant data showing the p38 is a major signaling pathway contributing to LPS-induced periodontal bone destruction. Based upon these data, we hypothesize that the endogenous negative regulator mechanism of p38 signaling, MKP-1, is a key component of responsible for attenuation of LPS-induced inflammatory cytokine expression in macrophages. In this proposal, the ability of TIP 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 determine the role of over-expressed MKP-1 on IL-6 and TNFa mRNA expression in vitro. 2) To determine the contribution of MKP-1 in ontogeny of inflammatory cytokine production and LPS-induced osteoclastogenesis in primary bone marrow macrophages and 3) To determine the impact of MKP-1 in inflammatory bone destruction in vivo using MKP mice. These studies will establish the role of LPS-induced cytokine expression and negative regulation in inflammatory bone loss through selective attenuation of p38 MAPK-induced signaling in periodontal bone destruction.