PLATELET PRODUCTION AND MODIFICATION OF INFLAMMATORY HA FRAGMENTS IN COLITIS

说明）： （项目3，de拉莫特）结肠炎中血小板的产生和炎症性HA片段的修饰- 聚糖-rlch细胞外基质（ECM）是一个经常被忽视的因素，在调查中， 炎症然而，越来越多的证据表明ECM，特别是透明质酸（HA）， 免疫细胞微环境中的动态参与者。HA片段正受到关注， “内源性危险信号”，调节先天免疫反应，经常促进炎症。 然而，在细胞环境中产生足够数量的片段来介导 尚未确定答复。我们有证据表明血小板在细胞外产生HA片段， 通过两种机制在环境中：1）从活化的小血管表面切割HA 内皮通过其表面透明质酸酶HYAL 2;和2）内源性内部HA的挤出 在激活期间。我们假设血小板通过产生信号大小的HA片段， 并使炎症持续存在。首先，我们建议确定导致血小板聚集的细胞事件级联。 从内皮细胞表面切割HA片段，以生物化学表征释放的HA，以及 测试这种级联反应的中断是否会影响结肠炎小鼠模型的炎症。二是 建议确定血小板中HA的来源和释放HA的细胞机制， 生物化学表征这种内源性HA，并测试血小板HA的缺失是否影响 在体内结肠炎模型中的炎症。第三，我们建议测试是否HA片段产生的 血小板HYAL 2剪切，或血小板在脱粒过程中释放的HA片段，或商业纯化的 与血小板产生的碎片大小相似的HA将激活单核细胞和血小板本身。最终 这些研究将确定两种新的聚糖介导的机制， 炎症是与包括IBD在内的许多疾病有关的具有很大临床意义的领域。数据可能会 显示了一个有组织的途径，通过该途径，ECM在被血小板修饰后，有助于 炎症反应。 相关性（参见说明）： 血小板除了在凝血中起核心作用外，还被认为是炎症介质。我们 提出血小板通过产生促炎HA片段，促进炎症循环 在微脉管系统内，其加剧和延续慢性炎性疾病，例如 炎性肠病。

instmctions): (Project 3, de la Motte) Platelet Production and Modification of Inflammmatory HA Fragments in Colitis - The glycan-rlch extracellular matrix (ECM) is a commonly overlooked element in the investigation of inflammation. However, an increasing body of evidence implicates ECM, especially hyaluronan (HA) as a dynamic participant in the immune cell microenvironment. HA fragments are gaining attention as 'endogenous danger signals' that regulate Innate Immune responses and frequently promote inflammation. Yet specific mechanisms that create fragments in the cellular environment in sufficient quantity to mediate responses have not been defined. We have evidence that platelets produce HA fragments in extracellular environments by two mechanisms: 1) cleavage of HA from the surface of activated, small vessel endothelium by means of their surface hyaluronidase, HYAL2; and 2) extrusion of endogenous, internal HA during activation. We hypothesize that platelets, by generating signaling sized HA fragments, exacerbate and perpetuate inflammation. First, we propose to identify the cascade of cellular events that lead platelets to cleave HA fragments from endothelial cell surfaces, to biochemically characterize the HA liberated, and to test whether interruption of this cascade will impact inflammation in a mouse model of colitis. Second, we propose to determine the source of HA in platelets and the cellular mechanism that releases it, to biochemically characterize this endogenous HA, and to test whether deletion of platelet HA affects inflammation in the in vivo colitis model. Third, we propose to test whether HA fragments produced by platelet HYAL2 clipping, or HA fragments released by platelets during degranulation, or commercial purified HA of similar sizes to platelet created fragments will activate monocytes and platelets themselves. Ultimately these studies will define two new, glycan-mediated mechanisms whereby platelets contribute to inflammation, an area of great clinical interest pertaining to many diseases Including IBD. The data will likely show an organized pathway through which the ECM, after modification by platelets, contributes to inflammatory responses. RELEVANCE (See instructions): Platelets, in addition playing a central role in coagulation, are recognized as mediators of inflammation. We propose that platelets, by producing pro-inflammatory HA fragments, contribute to a cycle of inflammation within the microvasculature that exacerbates and perpetuates chronic inflammatory diseases, such as inflammatory bowel disease.