PMN integrins, apoptosis and inflammation

PMN 整合素、细胞凋亡和炎症

• 批准号: 6613550
• 负责人: William S. Hendey
• 金额: $ 29万
• 依托单位: RUSH UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-02-01 至 2008-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6613550
• 关键词: CD95 molecule; apoptosis; cell adhesion; ceramides; clinical research; confocal scanning microscopy; cytokine receptors; enzyme activity; flow cytometry; human subject; immunofluorescence technique; inflammation; integrins; laboratory rat; lung injury; myeloperoxidase; neutrophil; phlebotomy; protein isoforms; protein kinase C; protein localization; protein structure function; receptor expression; tumor necrosis factor alpha; vascular endothelium

DESCRIPTION (provided by applicant): The participation of Polymorphonuclear neutrophils (PMN) in the inflammatory response provides a first line of defense against invading organisms. However, inflammation has been called "double edged sword" as PMN can cause damage to surrounding tissues and a prolonged inflammatory response can contribute to a variety of pathological conditions. The recruitment of circulating PMN to inflammatory sites requires the stimulated adhesion of PMN to the endothelium followed by their extravasation and chemotaxis. The beta2 integrins, alpha-L beta-2 and alpha-M beta-2 mediate the tight adhesion of PMN to the endothelial cells required for subsequent extravasation. Although the beta2 integrins have been widely studied, the focus has been on identifying conformational changes necessary for adhesion while the cellular signaling pathways responsible for regulating beta2 mediated adhesion of PMN remain poorly understood. We have identified a signaling pathway associated with PMN apoptosis that attenuates the beta2 mediated adhesion of PMN to pulmonary microvascular endothelial cells. Stimulation of the PMN Fas "death" receptor results in a reduction of PMN adhesion to pulmonary microvascular endothelial cells. Preliminary data indicates that the loss of adhesion is a very early event in the Fas/Ceramide/Protein Kinase Cdelta (PKCdelta) pathway that contributes to PMN apoptosis. Specifically, Fas activation increases PMN ceramide concentration and causes the cytosolic localization of PKCdelta. We propose that the cytosolic localization of PKCdelta could reduce adhesion because it opposes the membrane localization of PKCdelta that is necessary for beta2 mediated adhesion. Aim 1 examines the two beta2 integrin receptors on PMN, alpha-L beta-2 and alphaM beta2, that mediate endothelial cell adhesion to determine which of the beta2 receptors are affected by Fas activation. Aim 2 determines the effect of Fas activation on PKCdelta and manipulates the cellular localization of PKCdelta to determine its effects on the beta2 integrins and adhesion. Aim 3 examines the effects of Fas on ceramide to confirm that ceramide increases mediate Fas effects on PKCdelta, beta2 integrins, and adhesion. Aim 4 determines if reducing adhesion by manipulating the Fas/ceramide/PKCdelta pathway can also reduce ischemia/reperfusion-induced injury in an ex-vivo rat lung. An understanding of this pathway would provide novel targets for the control of inflammation.

描述（由申请人提供）： 多形核中性粒细胞 (PMN) 参与炎症反应，提供了抵御入侵生物体的第一道防线。 然而，炎症被称为“双刃剑”，因为中性粒细胞会对周围组织造成损害，而长期的炎症反应会导致多种病理状况。 将循环中的中性粒细胞募集至炎症部位需要刺激中性粒细胞与内皮的粘附，然后进行外渗和趋化。 beta2 整合素、α-L beta-2 和 alpha-M beta-2 介导 PMN 与随后外渗所需的内皮细胞的紧密粘附。 尽管β2整合素已被广泛研究，但重点是识别粘附所需的构象变化，而负责调节β2介导的PMN粘附的细胞信号通路仍然知之甚少。我们已经确定了与中性粒细胞凋亡相关的信号通路，该通路减弱了β2介导的中性粒细胞与肺微血管内皮细胞的粘附。 刺激 PMN Fas“死亡”受体会导致 PMN 对肺微血管内皮细胞的粘附减少。 初步数据表明，粘附丧失是 Fas/神经酰胺/蛋白激酶 Cdelta (PKCdelta) 通路中的一个非常早期的事件，有助于 PMN 凋亡。 具体来说，Fas 激活会增加 PMN 神经酰胺浓度并导致 PKCdelta 的胞质定位。 我们认为 PKCdelta 的胞质定位可以减少粘附，因为它反对 PKCdelta 的膜定位，而膜定位是 beta2 介导的粘附所必需的。 目标 1 检查 PMN 上的两个 β2 整联蛋白受体：α-L beta-2 和 alphaM beta2，它们介导内皮细胞粘附，以确定哪些 β2 受体受到 Fas 激活的影响。 目标 2 确定 Fas 激活对 PKCdelta 的影响，并操纵 PKCdelta 的细胞定位以确定其对 β2 整联蛋白和粘附的影响。 目标 3 检查 Fas 对神经酰胺的影响，以确认神经酰胺增加介导 Fas 对 PKCdelta、β2 整合素和粘附的影响。 目标 4 确定通过操纵 Fas/神经酰胺/PKCδ 途径减少粘附是否也可以减少离体大鼠肺中缺血/再灌注引起的损伤。 对这一途径的理解将为控制炎症提供新的靶标。