Novel Lipid Mediators in Neutrophil Signal Transduction

该研究中心的研究表明，人类细胞将花生四烯酸和ω-3脂肪酸转化为高效的抗炎剂，促进炎症的消退[例如，消退素、二十二碳三烯（DT）、脂氧素]。这些脂质介质（LM）的生物合成需要细胞-细胞相互作用，并受到细胞因子和阿司匹林的高度影响。这些介质在体外抑制中性粒细胞（PMN）的某些功能反应，并在几种急性炎症模型中阻止白细胞的流入，包括牙周炎破坏。虽然已经鉴定了其中一些LM的受体，但这些受体所采用的信号传导途径在很大程度上仍然未知。实验在此 这些建议旨在填补这一空白。具体来说，这个子项目集中在四个未开发的领域的信号转导途径在中性粒细胞。这些是：（1）鉴定PMN中消退素和DT的受体，并阐明当这些受体被占据时变得激活的信号转导途径;（2）确定消退素和DT各自如何影响PMN中的p38-MAPK级联以及白细胞特异性蛋白1（LSP 1）在该途径中的确切功能;（3）确定局限性侵袭性牙周炎（Localized aggressive periodontitis，牙周炎）患者PMN中LSP 1磷酸化水平降低的生化基础，并确定这是否是牙周炎患者PMN功能缺陷的原因，和（4）建立由消退素和DT改变的PMN的功能反应，并评估这些治疗潜力 组织生物工程植入物研究中的化合物，用于重建颅面手术。生物化学（酶学），分子生物学（敲除实验，蛋白质表达），细胞生物学（IF显微镜）和动物病理生理学（组织生物工程）的技术将在这些调查中使用。这些研究应该为阿司匹林和omega-3脂肪酸对各种炎症性疾病的有益作用提供新的机制见解，并可能导致治疗这些疾病的新疗法。

Studies in this Research Center have shown that human cells convert arachidonate and omega-3 fatty acids into highly potent, anti-inflammatory agents that promote the resolution of inflammation[e.g., resolvins, docosatrienes (DT), lipoxins]. Biosynthesis of these lipid mediators (LM) requires cell-cell interactions and is highly influenced by the presence of cytokines and aspirin. These mediators inhibit certain functional responses of neutrophils (PMN) in vitro and prevent influx of leukocytes in several models of acute inflammation including peridontal destruction. While receptors for some of these LM have been identified, the signaling pathways employed by these receptors remain largely unknown. Experiments presented in this proposal are aimed at filling this gap. Specifically, this sub-Project focuses on four unexplored areas of the signal transduction pathways in PMN. These are: (1) identifying receptors for the resolvins and DT in PMN and elucidating the signal transduction pathways that become activated when these receptors are occupied; (2) determining how resolvins and DT each impact the p38-MAPK cascade in PMN and the exact function(s) of leukocyte specific protein 1 (LSP1) in this pathway; (3) determine the biochemical basis for the reduced phosphorylation of LSP 1 in PMN from patients with localized aggressive periodontitis (LAP) and establish if this is responsible for the PMN functional defects in LAP, and (4) establish the functional responses of PMN that are altered by resolvins and DT, and evaluate the therapeutic potential of these compounds in tissue bioengineering implant studies for use in reconstructive craniofacial surgery. Techniques of biochemistry (enzymology), molecular biology (knockout experiments, protein expression), cell biology (IF microscopy) and animal pathophysiology (tissue bioengineering) will be employed in these investigations. These studies should provide new mechanistic insights into the beneficial effects of aspirin and omega-3 fatty acids on a variety of inflammatory diseases, and may result in new therapies to treat these conditions.