Sphingosine Phosphate Role in Inflammation

描述（由申请人提供）：该项目的长期目标是确定鞘氨醇-1-磷酸（S1P）介导的新型脂质途径在炎症中的作用，并建立该途径的成分作为抗炎治疗的潜在新靶点。PI的实验室在鞘脂代谢和功能方面拥有成熟的专业知识记录。前期资助期的研究使我们在S1P在炎症中的作用和调控方面进入了一个令人兴奋的新方向。S1P是由鞘氨醇激酶（SK）在包括炎症细胞在内的许多细胞类型中磷酸化产生的。S1P在细胞外通过与g蛋白偶联受体S1P1-5的成员结合或在细胞内作用于定义不明确的靶标。它介导多种生物活性，包括有丝分裂、细胞存活、血管生成和炎症反应。在这一竞争性更新中，我们有令人信服的新数据，由此我们暗示该途径是环氧化酶-2 （COX-2）表达和前列腺素E2 （PGE2）产生的关键调节因子。此外，我们发现SK1在炎症组织中显著过表达。我们还证明细菌脂多糖（LPS）调节SK1。因此，这一提议将验证SK1和S1P调节炎症的假设，并且抑制这一途径可以抑制炎症反应。为了验证这一假设，我们提出以下目标：1)确定SK1和S1P通路在炎症中受到调节，并确定这种调节的机制。这将通过确定这一途径是否在炎症中受到调节，并研究炎症细胞模型中这种调节的机制，以及通过确定人类和动物炎症模型中炎症组织中SK1的表达和细胞类型分布来完成。2)建立SK1和S1P在炎症调节中的功能，确定该通路的作用机制。通过在细胞和体内炎症模型中评估SK1过表达和S1P处理的效果，并确定SK1和S1P调节炎症通路（NF-KB、IL2、TNF、ERKs、COX-2）的机制，证明SK1和S1P在调节炎症方面具有重要作用，从而实现这一目标。3)确定SK1和S1P是否为炎症所必需。这将通过使用小干扰RNA阻断SK1和/或显性阴性SK1在细胞和体内的活性来实现。此外，我们将测试我们合成的不同化合物在细胞和体内炎症模型中抑制SK1或拮抗S1P受体的能力。这些研究将使我们能够深入了解这一途径在炎症反应中的作用，并可能为炎症提供新的治疗方法。

DESCRIPTION (provided by applicant): The long-term goal of this project is to define the role of the novel lipid pathway mediated by sphingosine-1- phosphate (S1P) in inflammation and to establish components of this pathway as potential novel targets for anti-inflammatory therapy. The PI's laboratory has an established track record of expertise in sphingolipid metabolism and function. Studies from the previous funding period have led us into a novel exciting direction on the role and regulation of S1P in inflammation. S1P is generated by phosphorylation by sphingosine kinase (SK) in many cell types including inflammatory cells. S1P acts extracellularly by binding to members of the G-protein coupled receptors S1P1-5, or intracellularly on poorly defined targets. It mediates several biologic activities, including mitogenesis, cell survival, angiogenesis and inflammatory responses. In this competing renewal we have compelling new data, whereby we have implicated this pathway as a key regulator of cyclooxygenase-2 (COX-2) expression and prostaglandin E2 (PGE2) production. In addition we find that SK1 is significantly overexpressed in inflammatory tissues. We also demonstrate that bacterial lipopolysaccharide (LPS) regulates SK1. This proposal will therefore, test the hypothesis that SK1 and S1P regulate inflammation, and that inhibiting this pathway could inhibit inflammatory responses. To test this hypothesis we propose the following aims: 1) Establish that the SK1 and S1P pathway is regulated in inflammation and determine the mechanisms of this regulation. This will be done by determining if this pathway is regulated in inflammation and studying the mechanisms of this regulation in cell models of inflammation, and by determining the expression and cell-type distribution of SK1 in inflammatory tissues from humans and from animal models of inflammation. 2) Establish the function of SK1 and S1P in regulation of inflammation and determine the mechanisms of action of this pathway. This will be done by demonstrating that SK1 and S1P have a significant role in regulating inflammation by evaluating the effect of over expression of SK1 and of S1P treatment in cells and in vivo models of inflammation, and determining the mechanisms by which SK1 and S1P regulate inflammatory pathways (NF-KB, IL2, TNF, ERKs, COX-2). 3) Determine if SK1 and S1P are necessary for inflammation. This will be done by blocking SK1 activity in cells and in vivo using small interfering RNA to SK1 and/or dominant negative SK1. In addition we will test different compounds that we synthesized for their ability to inhibit SK1 or to antagonize S1P receptors in cells and in vivo models of inflammation. These studies will enable us to gain important insight into the role of this pathway in inflammatory responses and may also provide novel therapeutic approaches to inflammation.