Epigenetic Modulation of GvHD and GvL

异基因造血干细胞移植(allo-HSCT)是治疗慢性粒细胞白血病的唯一有效方法。 复发/难治性白血病。Allo-HSCT治疗恶性血液病的疗效如下 主要来源于移植物抗白血病(GVL)效应，这种效应由成熟的供者T细胞介导 骨髓移植。不幸的是，同样的捐赠者T细胞也可以调节有益的GVL效应 导致移植物抗宿主病(GvHD)，这是allo-HSCT的主要威胁生命的并发症。管理 GvHD的威胁，同时最大限度地发挥有益的GVL效应，将扩大 Allo-HSCT程序，CD4+CD25+FOXP3+调节性T细胞(Treg)已被证明可预防GvHD。 在不牺牲GVL的情况下抑制同种异体反应性供者T细胞的临床前研究，从而提供 前景看好的治疗方案。不幸的是，有几个限制阻碍了Tregs的常规临床应用： 1)外周血中Tregs的低循环数，2)体外培养后抑制活性的丧失 在体外扩增的Treg缺乏必需的Treg特异性表面标记。我们 先前报道DNA甲基转移酶抑制剂氮杂胞苷(AzaC)诱导Foxp3表达 并在体内增加供体Tregs，从而在不取消GVL的情况下减轻小鼠allo-HSCT中的GvHD 模特。令人惊讶的是，我们发现AzaC介导的GvHD抑制不依赖于Foxp3，即 主控调节器的Treg功能。我们鉴定了三个被AzaC高度上调的候选基因 抗CD3/CD28珠状和APC激活的CD4+/CD25-T细胞，这可能是导致 基于全基因组RNA图谱分析的AzaC诱导的Tregs的抑制功能。我们假设 AzaC将在人类T细胞中诱导类似的免疫调节效应。在这个孢子项目中，我们将 急性髓系白血病和骨髓增生异常综合征患者接受异基因干细胞治疗的安全性和有效性评价 移植(目标1)，并将进行机制研究，以确定AzaC和其他DNMT1抑制剂如何 在体内外对移植物抗宿主病和移植物抗宿主病发挥免疫调节作用。(目标2)。

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only curative treatment for patients with relapsed/refractory leukemia. The therapeutic benefits of allo-HSCT for hematologic malignancies are primarily derived from a graft-versus-leukemia (GvL) effect that is mediated by mature donor T cells present in the bone marrow graft. Unfortunately, the same donor T cells that mediate the beneficial GvL effect can also cause graft-versus-host disease (GvHD), the major life-threatening complication of allo-HSCT. Managing the threat of GvHD while maximizing the beneficial GvL effect would broaden the scope and usefulness of allo-HSCT procedures, CD4+CD25+FOXP3+ regulatory t cells (Tregs) have been shown to prevent GvHD in preclinical studies by suppressing alloreactive donor T cells without sacrificing GvL, thereby providing a promising treatment option. Unfortunately, several limitations have prevented the routine clinical use of Tregs: 1) the low circulating numbers of Tregs in peripheral blood, 2) loss of suppressor activity following in vitro expansion and 3) the lack of Treg-specific surface markers necessary to purify in vitro expanded Tregs. We previously reported that the DNA methyltransferase inhibitor azacitidine (AzaC)-induced Foxp3 expression and increased donor Tregs in vivo, thereby mitigating GvHD without abrogating GvL in a murine allo-HSCT model. Surprisingly, we found that AzaC-mediated suppression of GvHD was independent of Foxp3, the master regulator of Treg function. We identified three candidate genes that are highly upregulated by AzaC in anti-CD3/CD28 bead- and APC-activated CD4+/CD25- T cells and which might be responsible for the suppressor function of AzaC-induced Tregs based on genome-wide RNA profiling analyses. We hypothesize that AzaC will induce similar immunomodulatory effects in human T cells. In this SPORE project we will assess the safety and efficacy of AzaC in patients with AML and MDS undergoing allogeneic stem cell transplant (Aim 1) and will perform mechanistic studies to determine how AzaC and other DNMT1 inhibitors exert their immunomodulatory effects on GvHD and GvL in vitro and in vivo. (Aim 2).