Cell signaling in granulocyte transfusion

中性粒细胞输注通常用作治疗危及生命的 严重贫血患者的细菌和真菌感染。然而，其临床 结果通常受到离体保存期短和体内快速死亡、募集效率低的阻碍 移植的中性粒细胞对病原体的杀伤能力差。最终 这项研究的目标是识别和表征细胞和分子事件， 改善输血过程中中性粒细胞性能。我们特别感兴趣的是 由肌醇磷脂Ptdlns（3，4，5）P3介导。最近，我们已经证明， 在PTEN基因敲除小鼠中，中性粒细胞对化学引诱物刺激的反应大大增强， Ptdlns（3，4，5）P3信号转导被过度激活。中性粒细胞向炎症腹膜的募集 在这些小鼠中腔显著升高。此外，通过增加PtdIns（3，4，5）P3信号， 消耗PTEN防止中性粒细胞自发死亡。此外，我们最近报告说， 中性粒细胞的功能，如趋化性，氧化爆发，募集到炎症部位， 在lnsP 3 KB-1中性粒细胞中也增强，其中Ptdlns（3，4，5）P3信号由于 lns（1，3，4，5）P4的耗竭，Ptdlns（3，4，5）P3信号传导的细胞内抑制性调节剂。这些 有趣的结果使我们假设中性粒细胞输注的疗效可以通过以下方法提高： 增强嗜中性粒细胞中Ptdlns（3，4，5）P3信号传导。在这项研究中，我们将使用一只老鼠， 中性粒细胞输注模型来检验这一假设。首先，我们将研究是否增加 PtdIns（3，4，5）P3信号传导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清除入侵病原体的能力上，我们将确定在输注的中性粒细胞中增强Ptdlns（3，4，5）P3信号传导是否可以最终增强接受者小鼠的炎症反应和细菌杀伤能力（目的II）。本研究的目的是深入研究Ptdlns（3，4，5）P3通路在提高中性粒细胞输注后功能中的作用机制，并将Ptdlns（3，4，5）P3及其相关通路作为改善中性粒细胞输注后功能的新靶点。本研究的最终目标是符合当前PPG的总体主题，即“在分子水平上了解输注的血细胞如何发挥作用”。

Neutrophil transfusion has been commonly utilized as a therapeutic approach for the treatment of lifethreatening 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 ofthe 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 ofthe 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 oeneral theme of current PPG which is "to understand how transfused blood cells function at a molecular level"