Cell signaling in granulocyte transfusion

中性粒细胞输注通常被用作治疗严重贫血患者中危及生命的细菌和真菌感染的治疗方法。然而，其临床结果通常受到离体保存期短和体内快速死亡、炎症部位募集效率低以及移植中性粒细胞的病原体杀伤能力差的阻碍。拟议研究的最终目标是识别和表征可以改善输血期间中性粒细胞性能的细胞和分子事件。我们特别感兴趣的是肌醇磷脂Ptdlns（3，4，5）P3介导的信号通路。最近，我们已经表明，在Ptdlns（3，4，5）P3信号过度激活的PTEN敲除小鼠中，中性粒细胞对化学引诱物刺激的反应性大大增强。在这些小鼠中，中性粒细胞向发炎的腹膜腔的募集显著升高。此外，通过消耗PTEN增强Ptdlns（3，4，5）P3信号可防止中性粒细胞自发性死亡。此外，我们最近报道，中性粒细胞的功能，如趋化性，氧化爆发，招募到炎症部位， 在lnsP 3 KB-/-中性粒细胞中也增加，其中Ptdlns（3，4，5）P3信号由于lns（1，3，4，5）P4（Ptdlns（3，4，5）P3信号传导的细胞内抑制性调节剂）的耗尽而升高。这些有趣的结果使我们假设中性粒细胞输注的功效可以通过增强中性粒细胞中的Ptdlns（3，4，5）P3信号传导来改善。在这项拟议的研究中，我们将使用小鼠中性粒细胞输血模型来检验这一假设。首先，我们将研究增加Ptdlns（3，4，5）P3信号传导是否可以增强输注的中性粒细胞的存活（目的1-实验A和实验B）。 B）。此外，我们还将检查是否有输血中性粒细胞募集到的网站， 炎症通过升高PtdIns（3，4，5）P3信号传导而增强（目的I-实验C和D）。最后，由于输注的中性粒细胞的性能最终反映在接受者的免疫功能上， 清除入侵的病原体，我们将确定是否增加Ptdlns（3，4，5）P3信号转导， 输注中性粒细胞可最终增强炎症反应和杀菌能力 的受体小鼠（Aim II）。在这项研究中提出的实验将提供深入了解 Ptdlns（3，4，5）P3通路在提高输注中性粒细胞功能中的作用机制， 最终目标是巩固PtdIns（3，4，5）P3和相关途径作为新的治疗靶点 用于改善中性粒细胞在中性粒细胞输注中的性能。这个项目的最终目标 研究是根据目前PPG的总主题，即“了解如何 输注的血细胞在分子水平上发挥作用”。

Neutrophil transfusion has been commonly utilized as a therapeutic approach for the treatment of life-threatening bacterial and fungal infections in severe neutropenic patients. However, its clinical outcome is often hampered by short ex vivo shelf life and rapid in vivo death, inefficiency of recruitment to sites of inflammation, and poor pathogen killing capability of transplanted neutrophils. The ultimate goal of the proposed research is to identify and characterize cellular and molecular events that can improve neutrophil performance during transfusion. We are particularly interested in a signal pathway mediated by inositol phospholipid Ptdlns(3,4,5)P3. Recently, we have shown that the responsiveness of neutrophil to chemoattractant stimulation is much enhanced in PTEN knockout mice in which the Ptdlns(3,4,5)P3 signaling is hyperactivated. The recruitment of neutrophils to the inflamed peritoneal cavity was significantly elevated in these mice. In addition, augmenting Ptdlns(3,4,5)P3 signal via depleting PTEN prevents neutrophil spontaneous death. Moreover, we recently reported that neutrophil functions, such as chemotaxis, oxidative burst, recruitment to the sites of inflammation, were also augmented in lnsP3KB-/- neutrophils, in which the Ptdlns(3,4,5)P3 signal is elevated due to the depletion of lns(1,3,4,5)P4, an intracellular inhibitory modulator of Ptdlns(3,4,5)P3 signaling. These intriguing results led us to hypothesize that the efficacy of neutrophil transfusion can be improved by augmenting Ptdlns(3,4,5)P3 signaling in neutrophils. In this proposed study, we will use a mouse neutrophil transfusion model to test this hypothesis. First, we will investigate whether augmenting Ptdlns(3,4,5)P3 signaling can enhance the survival of transfused neutrophils (Aim l-Experiment A and B). In addition, we will examine whether the recruitment of transfused neutrophils to the sites of inflammation is enhanced by elevating Ptdlns(3,4,5)P3 signaling (Aim I- Experiment C and D). Finally, since the performance of transfused neutrophils is eventually reflected by the recipients' capability of clearing invading pathogens, we will determine whether augmenting Ptdlns(3,4,5)P3 signaling in transfused neutrophils can ultimately enhance the inflammatory response and bacteria killing capability of the recipient mice (Aim II). Experiments proposed in this study will provide insight into the mechanism of action of Ptdlns(3,4,5)P3 pathway in elevating the function of transfused neutrophils, with the ultimate goal of solidifying Ptdlns(3,4,5)P3 and related pathways as novel therapeutic targets for improving the performance of neutrophils in neutrophil transfusion. The ultimate goal of this research is in accordance with the general theme of current PPG which is "to understand how transfused blood cells function at a molecular level".