Cell signaling in granulocyte transfusion

项目摘要 粒细胞输注（GTX）已被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，其临床结果往往 受炎症部位募集效率低、体内快速死亡和病原体杀灭效果差的阻碍 移植中性粒细胞的能力。拟议研究的最终目标是确定和 表征在粒细胞移植期间可以改善中性粒细胞性能的细胞和分子事件 输血在上一个资助期，我们证明了提高细胞内PtdIns（3，4，5）P3信号转导 通过破坏PTEN途径增强中性粒细胞功能，增加细菌清除，并减少 在一个小鼠模型中的血小板相关性肺炎的死亡率。我们进一步发现， 输注的中性粒细胞的破坏显著提高了粒细胞输注的功效。这些 研究结果证实了PtdIns（3，4，5）P3通路作为改善临床症状的治疗靶点的有效性。 粒细胞输注的结果。然而，PTEN是一种众所周知的肿瘤抑制因子， 与许多实体癌和血液癌的肿瘤发生有关， 作为治疗目标。最近，我们报道了中性粒细胞中PtdIns（3，4，5）P3信号也可以升高， 通过破坏InsP 6 K1，一种负责合成InsP 7的酶，InsP 7是一种细胞溶质分子， 调节PtdIns（3，4，5）P3信号转导。InsP 6 K1缺陷型中性粒细胞具有增强的细菌杀灭作用 能力和他们的招聘到炎症部位增加。重要的是，纯合子InsP 6 K1 KO小鼠是活的并且不显示任何大体的身体或行为异常。没有任何肿瘤 在这些老鼠身上发现的。基于这些有趣的结果，我们假设InsP 6 K1的破坏应该 是一种更安全，但同样有效的治疗策略，以改善粒细胞输注。在此提出的 在这项研究中，我们将使用小鼠血小板减少相关肺炎模型来验证这一假设。一是 研究破坏InsP 6 K1是否可以提高PtdIns（3，4，5）P3信号并增加积聚 （包括募集和存活）的输血中性粒细胞在血小板减少症相关的大肠杆菌肺炎（目的I）。 此外，我们将确定是否在输注的中性粒细胞中破坏InsP 6 K1可以最终增强 宿主防御（Aim II），减轻（Aim III）青霉相关细菌和真菌的严重程度 肺炎最后，对于未来的临床干预，InsP 6 K1的抑制最有可能通过使用 化合物因此，我们将研究是否用InsP 6 K抑制剂TNP预处理也可以 增强粒细胞输注治疗血小板相关性肺炎的疗效（Aim IV）。因此在 根据PPG的总体主题，本研究将提供新的治疗靶点和/或 改善中性粒细胞在粒细胞输注中的表现，从而减轻 在移植周围环境中，血小板减少相关感染的严重程度。

Project Summary Granulocyte transfusion (GTX) has been utilized as a therapeutic approach for the treatment of life-threatening bacterial and fungal infections in severely neutropenic patients. However, its clinical outcome is often hampered by inefficiency of recruitment to sites of inflammation, rapid in vivo death, 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 granulocyte transfusion. In the last funding period, we demonstrated that elevating intracellular PtdIns(3,4,5)P3 signaling pathway by disrupting PTEN enhances neutrophil function, augments bacterial clearance, and reduces mortality rate in a murine model of neutropenia-associated pneumonia. We further revealed that PTEN disruption in transfused neutrophils significantly improves the efficacy of granulocyte transfusion. These findings confirm the validity of the PtdIns(3,4,5)P3 pathway as a therapeutic target for improving the clinical outcome of granulocyte transfusion. Nevertheless, PTEN is a well-known tumor suppressor and its disruption has been implicated in tumorigenesis of numerous solid and hematologic cancers, which renders it unsuitable as a therapeutic target. Recently, we reported that PtdIns(3,4,5)P3 signal in neutrophils can also be elevated by disrupting InsP6K1, an enzyme responsible for the synthesis of InsP7, a cytosolic molecule that negatively regulates PtdIns(3,4,5)P3 signaling. InsP6K1 deficient neutrophils possess an enhanced bacteria killing capability and their recruitment to the site of inflammation is augmented. Importantly, homozygous InsP6K1 KO mice are viable and do not display any gross physical or behavioral abnormalities. No tumors of any kind is discovered in these mice. Based on these intriguing results, we hypothesize that disruption of InsP6K1 should be a safer, yet equally effective therapeutic strategy for improving granulocyte transfusion. In this proposed study, we will use a mouse neutropenia-related pneumonia model to test this hypothesis. First, we will investigate whether disrupting InsP6K1 can elevate PtdIns(3,4,5)P3 signal and enhance the accumulation (including recruitment and survival) of transfused neutrophils in neutropenia-related E.coli pneumonia (Aim I). In addition, we will determine whether disrupting InsP6K1 in transfused neutrophils can ultimately enhance the host defense in (Aim II), and alleviate the severity of (Aim III) neutropenia-related bacterial and fungal pneumonia. Finally, for future clinical intervention, inhibition of InsP6K1 will most likely be achieved by using chemical compounds. Thus we will examine whether pre-treatment with an InsP6K inhibitor, TNP, can also augment the efficacy of granulocyte transfusion in neutropenia-related pneumonia (Aim IV). Thus, in accordance with the general theme of the PPG, this study will provide novel therapeutic targets and/or strategies for improving the performance of neutrophils in granulocyte transfusion and therefore alleviating the severity of neutropenia-related infection in the peri-transplant setting.