Effects of PGE2 on reconstitution of hematopoiesis and immunity after UCBT

描述(申请人提供)：脐带血移植(UCBT)的良好结果受到植入时间延长、免疫重建延迟和记忆T细胞晚倾斜的影响。斑马鱼和小鼠的研究表明，短暂的体外前列腺素E2(PGE2)暴露增加了HSC的数量，在体内的归巢和植入。我们进行了双UCBT(DUCBT)的Ib期临床试验，使用一个未经处理和一个体外PGE2处理的UCB单元，以确定安全性和植入参数。我们显示，与历史对照组相比，骨髓移植和PGE2来源的造血的中位时间显著缩短。我们确定，短期接触PGE2可稳定脐带血T细胞和树突状细胞(DC)中的b-连环蛋白。在脐带血T细胞中，前列腺素E_2通过EP2/EP4受体和cAMP介导的GSK3磷酸化修饰Wnt信号转导通路，从而稳定�-catenin和Tcf介导的转录。前列腺素E_2诱导的WNT靶基因，包括WNT途径的组成部分和WNT受体，表明PGE_2体外治疗在体内启动了T细胞的WNT/�-连环蛋白信号。Wnt/�-catenin信号在小鼠中已被证明可以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受者的T细胞体内扩增有限，CD8+群体中CD62+细胞比例增加，中央记忆样细胞的分子特征表现为转录因子Tcf7和eome表达增加，KLRG水平低，所有这些都受Wnt信号调节。此外，与对照组dUCBT接受者相比，通过TREC值和免疫序列测定，PGE2-UCBT接受者改善了胸腺重建的数量和质量。这些患者表现出强大的抗病毒免疫力，并减少了CMV和EBV病毒血症的发生率。这些结果在异基因造血干细胞移植中尤其重要，尤其是在脐带血移植中，免疫重建延迟的特点是记忆T细胞偏斜延迟和胸腺功能长期受损。我们的临床和实验室研究结果表明，PGE2处理的HSC的移植优势可能允许在成年患者中使用单个脐带血单位，PGE2可能通过在体内启动免疫细胞以启动Wnt介导的信号转导来改变天然免疫和获得性免疫的重建。为此，我们将进行以下研究：1)确定单个体外PGE2孵育的脐血单位移植的临床结果。2)检测PGE2体外孵育对T细胞分化、极化和功能的影响。3)检测PGE2体外孵育对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.