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

描述（由申请人提供）： 细胞因子的慢性产生介导炎性疾病。牙周病以及其他慢性炎症性骨疾病中的促炎细胞因子产生导致净骨丢失，最终对宿主功能产生负面影响。由多种细胞类型控制的复杂细胞因子网络决定了骨吸收中的细胞反应。促炎细胞因子，如白细胞介素（IL）-6，通过与下游细胞因子的相互作用调节骨吸收。细胞内信号通路通过多种潜在机制调节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 mRNA，p38已被证明在调节几种炎症介质（包括IL-6，IL-8和考克斯-2）的mRNA稳定性方面发挥重要作用。mRNA稳定性的转录后调控被认为是p38 MAP激酶的潜在作用。p38调控的分子机制还不清楚，但越来越多的研究表明，3'非翻译区（UTR）的顺式元件可能起着重要作用。针对该提议获得的初步数据表明，特异性p38 MAP激酶抑制剂SB 203580可以以剂量依赖性方式抑制IL-1诱导的IL-6表达。该机制已被证明依赖于从头蛋白质合成，并发生在转录后水平，其中在SB 203580的存在下，IL-6 mRNA的稳定性急剧下降。因此，该建议将集中于确定p38 MAP激酶在控制IL-6调节中的作用。拟议的研究可能是重要的，因为它们可能导致在转录后水平上调节IL-6表达的新型药理学试剂的开发。该提案的具体目标如下：1）通过构建p38 MAP激酶显性失活突变体并将p38 MAP激酶活性与IL-6 mRNA表达和稳定性相关联，确定p38 MAP激酶是成骨细胞中IL-1诱导的IL-6产生的关键调节因子，（2）确定IL-6 3'非翻译区（UTR）中介导p38 MAP激酶诱导IL-6 mRNA稳定性的顺式元件。这些研究将提供深入了解IL-6的特定序列元件是如何通过p38 MAP激酶和控制mRNA衰减速率来调节的。

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.