Cell signaling in granulocyte transfusion

中性粒细胞输注通常被用作治疗严重中性粒细胞减少症患者中危及生命的细菌和真菌感染的一种治疗方法。然而，其临床结果往往受到体外保质期短、体内死亡迅速、炎症部位募集效率低以及移植的中性粒细胞杀灭病原体能力差的影响。这项拟议研究的最终目标是识别和表征在输血过程中可以改善中性粒细胞性能的细胞和分子事件。我们对肌醇磷脂Ptdlns(3，4，5)P3介导的信号通路特别感兴趣。最近，我们发现在PTEN基因敲除小鼠中，Ptdlns(3，4，5)P3信号被过度激活，中性粒细胞对化学诱导剂刺激的反应性显著增强。在这些小鼠中，中性粒细胞向发炎的腹膜腔的募集显著增加。此外，通过去除PTEN来增强Ptdlns(3，4，5)P3信号可防止中性粒细胞自发死亡。此外，我们最近报道，中性粒细胞的功能，如趋化性，氧化爆发，募集到炎症部位，是 LNS(1，3，4，5)P4是Ptdlns(3，4，5)P3信号的细胞内抑制性调节剂，LNS(1，3，4，5)P4的缺失使Ptdlns(3，4，5)P3信号增强。这些有趣的结果使我们假设，通过增强中性粒细胞中的Ptdlns(3，4，5)P3信号可以提高中性粒细胞输注的有效性。在这项拟议的研究中，我们将使用小鼠中性粒细胞输注模型来验证这一假设。首先，我们将研究增强Ptdlns(3，4，5)P3信号是否可以提高输注的中性粒细胞的存活率(目的L-实验A和 b)。此外，我们将研究是否将输注的中性粒细胞招募到 炎症通过上调Ptdlns(3，4，5)P3信号而增强(目标I-实验C和D)。最后，由于输注中性粒细胞的性能最终由受者的能力来反映 清除入侵病原体，我们将确定是否增强Ptdlns(3，4，5)P3信号在 输注中性粒细胞可最终增强炎症反应和杀菌能力 受体小鼠的数量(AIM II)。这项研究中提出的实验将提供对 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Ptdlns(3，4，5)P3及其相关通路作为新的治疗靶点 为提高中性粒细胞输注中性粒细胞的性能。这样做的最终目的是 研究是符合当前PPG的总主题的，那就是“如何理解 输血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".