Mechanisms of Adenosine Protection

 描述(申请人提供)：粘膜炎症伴随着组织新陈代谢的显著变化。炎症的主要代谢特征之一是组织缺氧，最近被认为显著影响炎症性疾病的预后。在疾病过程的早期，这种“炎症性缺氧”在很大程度上是由于需要氧气的炎性细胞类型的招募，特别是中性粒细胞。在过去的两年里，我们在定义最初的假设方面取得了重大进展，即腺苷(ADO)在炎症反应早期通过直接作用于粘膜低氧诱导因子(HIF)稳定而发挥前馈抗炎机制的功能。利用新的体外系统、新的小鼠炎症模型和患者来源的材料，这项工作揭示了与抗炎ADO信号机制有关的一些重要特征。正在进行的工作已经确定了一个关键的信号轴，其中核苷酸代谢通过剔除核苷酸连接到HIF转录网络和稳定HIF所必需的E3连接酶。同样，这项工作发现了一种以前未被认识到的由激活的PMN释放的粘膜核苷酸来源，并在活动期炎症期间提供了一种潜在的丰富的ADO来源。基于这些初步研究，我们假设急性炎症过程中产生的核苷酸直接影响粘膜HIF的稳定和功能。三个特定的目标旨在验证这一假说：在特定的目标1中，我们将阐明粘膜中核苷酸代谢的机制。具体目标2将确定外切酶在粘膜炎症过程中对腺苷生成的相对贡献。具体目标3将研究中性粒细胞衍生的核苷酸在上皮HIF提供的粘膜保护中的作用。这项建议的总体目标是确定炎症性缺氧期间粘膜内HIF和ADO的新代谢信号。

 DESCRIPTION (provided by applicant): Mucosal inflammation is accompanied by substantial shifts in tissue metabolism. One of the major metabolic signatures of inflammation is tissue hypoxia, which is recently appreciated to significantly influence inflammatory disease outcome. Early in the disease process, such "inflammatory hypoxia" results, in large extent, from the recruitment of oxygen demanding inflammatory cell types, particularly neutrophils. In the past two years, we have made significant progress toward defining our original hypothesis that adenosine (Ado) generated early in the inflammatory response functions as a feed- forward anti-inflammatory mechanism through direct actions on mucosal hypoxia- inducible factor (HIF) stabilization. Utilizing new in vitro systems, novel murine models of inflammation and patient-derived materials, this work has revealed a number of important features related to mechanisms of anti-inflammatory Ado signaling. Ongoing work has defined a critical signaling axis wherein nucleotide metabolism is centrally coupled the HIF transcriptional network via cullin neddylation and the E3 ligase necessary for HIF stabilization. Likewise, this work has identified a previously unappreciated source of mucosal nucleotide released by activated PMN and provides a potentially rich source of Ado during active inflammation. Based on these preliminary studies, we hypothesize that nucleotides generated during acute inflammation directly impacts mucosal HIF stabilization and function. Three specific aims are directed at testing this hypothesis: In Specific Aim 1, we will elucidate mechanisms of nucleotide metabolism in the mucosa. Specific Aim 2 will define the relative contribution of ecto-enzymes to Ado generation during mucosal inflammation. Specific Aim 3 will examine the contribution of PMN-derived nucleotides on mucosal protection afforded by epithelial HIF. The overall aim of this proposal is to identify nove metabolic signaling by HIF and Ado within the mucosa during inflammatory hypoxia.