Effects of PGE2 on reconstitution of hematopoiesis and immunity after UCBT

描述（由申请人提供）：脐带血移植（UCBT）的良好结果受到移植时间延长，免疫重建延迟和晚期记忆T细胞倾斜的影响。斑马鱼和小鼠的研究表明，短暂的体外前列腺素E2 （PGE2）暴露会增加体内HSC的数量、归巢和植入。我们进行了双UCBT （dUCBT）的Ib期临床试验，使用一个未经治疗和一个体外pge2处理的UCB单元，以确定安全性和植入参数。我们证明，与历史对照和PGE2衍生的造血相比，骨髓植入的中位时间显着减少。我们确定，短时间暴露于PGE2诱导UCB T细胞和树突状细胞（dc）中b-连环蛋白的稳定。在UCB T细胞中，PGE2通过EP2/EP4受体和camp介导的Gsk3磷酸化修饰Wnt信号级联，导致¿-catenin和tcf介导的转录稳定。PGE2诱导Wnt靶基因，包括Wnt通路的组分，也包括Wnt受体，这表明体外PGE2处理为体内Wnt/ -catenin信号传导提供了T细胞。小鼠中的Wnt/¿-catenin信号传导已被证明可促进高效干细胞记忆CD8+ T细胞的产生。与我们的假设一致，我们发现PGE2-UCBT受体的T细胞在体内扩增有限，CD62+细胞比例在CD8+群体中增加，中枢记忆样细胞的分子特征以转录因子TCF7和EOMES的表达增加和低水平的KLRG为特征，所有这些都受Wnt信号调节。此外，通过TREC值和免疫seq测定，与对照dUCBT受体相比，PGE2-UCBT受体的胸腺定量和定性重建得到改善。这些患者表现出强大的抗病毒免疫力，减少了巨细胞病毒和EBV病毒血症的发生率。这些结果在同种异体造血干细胞移植，特别是UCBT中尤其重要，其中延迟免疫重建的特征是晚期记忆T细胞偏斜和胸腺功能的长期损害。我们的临床和实验室研究结果表明，PGE2治疗的HSC的移植优势可能允许在成人患者中使用单个UCB单元，并且PGE2可能通过在体内启动免疫细胞进行Wnt介导的信号传导来改变先天和适应性免疫的重建。为此，我们将开展以下研究：1)确定单体外PGE2孵育UCB单元移植的临床效果。2)观察体外PGE2培养对T细胞分化、极化和功能的影响。3)研究体外PGE2孵育UCB对DC分子和功能特性的影响。

DESCRIPTION (provided by applicant): The favorable outcome of umbilical cord blood transplantation (UCBT) is compromised by prolonged time to engraftment, delayed immunologic reconstitution and late memory T cell skewing. Zebrafish and mouse studies have shown that transient ex vivo prostaglandin E2 (PGE2) exposure increases HSC number, homing and engraftment in vivo. We performed a Phase Ib clinical trial of double UCBT (dUCBT), using one untreated and one ex vivo PGE2-treated UCB unit, to determine safety and engraftment parameters. We demonstrated a significant reduction in the median time to myeloid engraftment compared with historic controls, and PGE2- derived hematopoiesis. We determined, that short exposure to PGE2 induced stabilization of b-catenin in UCB T cells and dendritic cells (DCs). In UCB T cells PGE2 modified the Wnt signaling cascade through EP2/EP4 receptors and cAMP-mediated phosphorylation of Gsk3, resulting in stabilization of ¿-catenin and TCF-mediated transcription. PGE2 induced Wnt target genes, including components of the Wnt pathway but also Wnt receptors, suggesting that ex vivo PGE2 treatment primes T cells for Wnt/¿-catenin signaling in vivo. Wnt/¿-catenin signaling in mice has been demonstrated to promote the generation of highly potent stem cell memory CD8+ T cells. Consistent with our hypothesis, we found that T cells in PGE2-UCBT recipients displayed limited in vivo expansion, increase in CD62+ cell fraction in the CD8+ population and molecular features of central memory-like cells characterized by increased expression of transcription factors TCF7 and EOMES and low levels of KLRG, all of which are regulated by Wnt signaling. Furthermore, compared to control dUCBT recipients, PGE2-UCBT recipients had improved quantitative and qualitative thymic reconstitution as determined by TREC values and by immunoSEQ assay. These patients displayed potent antiviral immunity and reduced incidence of CMV and EBV viremia. These outcomes are of particular importance in allogeneic HSCT and specifically UCBT where delayed immune reconstitution is characterized by late memory T cell skewing and prolonged impairment of thymic function. Our clinical and laboratory findings suggest that the engrafting advantage of PGE2-treated HSC might allow for the use of a single UCB unit in adult patients, and that PGE2 might alter reconstitution of the innate and adaptive immunity by priming immune cells for Wnt mediated signaling in vivo. To these ends we will undertake the following studies to: 1) Determine the clinical outcome of single ex vivo PGE2 incubated UCB unit transplantation. 2) Examine the effect ex vivo PGE2 incubation of the UCB on the differentiation, polarization and function of T cells. 3) Examine the effects of ex vivo PGE2 incubation of the UCB on the molecular and functional properties of DC.