Mechanisms of Adenosine Protection

描述(申请人提供)：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低氧，最近被认为显著影响炎症性疾病的结局。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。近年来，我们一直专注于确定炎症性低氧启动的靶点和分子通路。这些研究的结果确定了一系列新的信号机制，其中缺氧(无论是在体外还是在体内)驱动细胞外核苷酸的代谢，从而产生大量的胞外腺苷。这一途径的中心是确定低氧诱导因子(HIF)是ADO代谢所必需的酶的重要调节因子(特别是。CD73)，从而确定HIF调节的腺苷生成是一种内源性抗炎途径。正在进行的研究表明，腺苷通过活跃的库林斯脱氢酶来调节缺氧诱导因子，库林斯是泛素连接酶招募的关键蛋白质家族。在这些初步研究的基础上，我们假设ADO在炎症反应早期通过直接作用于粘膜HIF稳定作为前馈抗炎机制发挥作用。有三个具体目标旨在验证这一假说：在具体目标1中，我们将定义中性粒细胞和上皮细胞在炎症部位对腺苷生成的贡献。特异性目标2将扩展初步数据，以阐明腺苷介导的Cullin-2脱氧机制。具体目标3将探讨腺苷在缺氧诱导因子介导的保护中的作用。这项建议的总体目标是确定炎性低氧期间粘膜内HIF和ADO的新的代谢信号。 公共卫生相关性：本提案旨在了解新陈代谢在炎症性肠病(IBD)等黏膜炎症中的作用。这里提出的研究结果将进一步解决炎症领域的一些悬而未决的问题，包括：什么类型的细胞对与炎症相关的代谢变化最有意义？这些代谢变化对组织是保护的还是有害的？这些新陈代谢的变化是否可以作为治疗的靶点？通过实验对这些问题的回答将为整合新的粘膜炎症治疗方法提供重要的基础。

DESCRIPTION (provided by applicant): Inflammation is accompanied by a substantial shift in tissue metabolism. One of the major metabolic signatures of inflammation is 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 recent years, we have focused on defining targets and molecular pathways set into motion by inflammatory hypoxia. Results from these studies have defined a series of novel signaling mechanisms in which hypoxia (both in vitro and in vivo) drives the metabolism of extracellular nucleotides toward the generation of large amounts of extracellular adenosine. Central to this pathway was the identification of hypoxia-inducible factor (HIF) as an important regulator of the enzymes necessary for Ado metabolism (esp. CD73), thus identifying HIF-regulated Ado production as an endogenous anti-inflammatory pathway. Ongoing studies have revealed that Ado regulates HIF through the active deneddylation of Cullins, a family of proteins critical for the recruitment of ubiquitin ligases. Based on these preliminary studies, we hypothesize that Ado generated early in the inflammatory response functions as a feed-forward anti- inflammatory mechanism through direct actions on mucosal HIF stabilization. Three specific aims are directed at testing this hypothesis: In Specific Aim 1, we will define the contribution of neutrophils and epithelia to Ado generation at sites of inflammation. Specific Aim 2 will extend preliminary data to elucidate mechanisms of Ado-mediated Cullin-2 de-neddylation. Specific Aim 3 will Probe the role of Ado to HIF-mediated protection. The overall aim of this proposal is to identify novel metabolic signaling by HIF and Ado within the mucosa during inflammatory hypoxia. PUBLIC HEALTH RELEVANCE: This proposal aims at understanding the role of metabolism in mucosal inflammation such as that observed in inflammatory bowel disease (IBD). Results from the studies proposed here will go far to resolve a number of unanswered questions in the field of inflammation, including: What cell types contribute most significantly to the metabolic changes associated with inflammation? Are these metabolic changes protective or detrimental to the tissue? Can these metabolic changes be targeted for therapeutic benefit? Answers to these questions through experiments proposed here will provide an important foundation for which to integrate novel therapeutic approaches for mucosal inflammation.