The Role of p38 MAP Kinase in IL-6 Gene Regulation

描述(由申请人提供)： 慢性细胞因子的产生会导致炎症性疾病。在牙周病以及其他慢性炎症性骨病中，促炎细胞因子的产生会导致净骨丢失，最终对宿主功能产生负面影响。一个由多种细胞类型控制的复杂的细胞因子网络，决定了骨吸收中的细胞反应。促炎细胞因子，如白介素6，通过与下游细胞因子相互作用来调节骨吸收。细胞内信号通路通过多种可能的机制调节IL-6。目前的建议将集中在p38丝裂原激活激酶(MAP)的作用以及该激酶如何调节成骨细胞中IL-6的mRNA，p38已被证明在调节包括IL-6、IL-8和COX-2在内的几种炎症介质的mRNA稳定性中发挥重要作用。转录后控制mRNA的稳定性被认为是p38 MAP激酶的一个潜在作用。P38调控的分子机制尚不清楚，但越来越多的研究表明，3‘非翻译区的顺式元件可能起着重要作用。初步数据表明，p38MAPK抑制剂SB203580能抑制IL-L诱导的IL-6表达，并呈剂量依赖关系。其机制已被证明依赖于从头蛋白质的合成，并发生在转录后水平，在SB203580存在下，IL-6mRNA的稳定性急剧下降。因此，这项建议将重点确定p38 MAP激酶在控制IL-6调节中的作用。这项拟议的研究可能很重要，因为它们可能导致开发在转录后水平上调节IL-6表达的新型药理制剂。本研究的具体目的如下：1)通过构建p38 MAP的主导负性突变体，并将p38 MAP的活性与IL-6的表达和稳定性相关联，以确定p38 MAP是IL-L诱导的成骨细胞产生IL-6的关键调控因子；2)确定介导p38 MAP诱导的IL-6的稳定性的IL-6 3‘非翻译区的顺式元件。这些研究将深入了解IL-6的特定序列元件是如何被p38 MAP激酶调制并控制mRNA衰减率的。

DESCRIPTION (provided by applicant): Chronic production of cytokines mediates inflammatory diseases. Proinflammatory cytokine production in periodontal disease, as well as other chronic inflammatory bone diseases, results in a net bone loss that ultimately negatively affects host function. A complex cytokine network controlled by many cell types, dictates cellular response in bone resorption. Proinflammatory cytokines, such as interleukin (IL)-6, regulate bone resorption through interaction with downstream cytokines. Intracellular signaling pathways regulate IL-6 through a variety of potential mechanisms. This current proposal will focus on the role of p38 mitogen activated kinase (MAP) and how this kinase regulates IL-6 mRNA in osteoblasts, p38 has been shown to play a significant role in regulation of mRNA stability of several inflammatory mediators including IL-6, IL-8, and COX-2. Post-transcriptional control of mRNA stability has been implicated as a potential role of p38 MAP kinase. The molecular mechanisms that underlie p38 regulation are poorly understood, but increasing evident from other studies suggests that cis elements of the 3' untranslated region (UTR) may play a major role. Preliminary data obtained for this proposal indicates that a specific p38 MAP kinase inhibitor, SB203580, can inhibit IL-l-induced expression of IL-6 in a dose dependent manner. The mechanism has been shown to depend upon de novo protein synthesis and occurs at the post-transcriptional level where IL-6 mRNA stability in dramatic decreased in the presence of SB203580. Thus, this proposal will focus establishing the role of p38 MAP kinase in controlling IL-6 regulation. The proposed studies may be important because they could lead towards the development of novel pharmacological agents that regulate IL-6 expression at the post-transcriptional level. The specific aims of the proposal are the following: 1) To establish that p38 MAP kinase is a key regulator of IL-l-induced IL-6 production in osteoblastic cells through construction of dominate negative mutants of p38 MAP kinase and correlating p38 MAP kinase activity with IL-6 mRNA expression and stability, and 2) To determine the cis elements of IL-6 3' untranslated region (UTR) that mediate p38 MAP kinase-induced IL-6 mRNA stability. These studies will provide insight into how specific sequence elements of IL-6 are modulated by p38 MAP kinase and control mRNA decay rates.