Fas/FasL mediated apoptosis in GVHD and aplastic anemia

稳定转导淋巴-造血祖细胞(HSCs)的能力使我们能够 对造血干细胞及其后代进行基因工程，作为治疗疾病和并发症的改良细胞工具。在具体目标1中，我们建议在小鼠和人类模型上进行临床前研究，以证实这一概念并阐明Fas配体转导的树突状细胞(DCs)或HSCs选择性杀伤介导GVHD的T细胞和NK细胞的主要细胞和分子机制。AIM 1的结果还将提供应用转导的FasL+细胞来减少严重再生障碍性贫血(SAA)中对HSCs的免疫攻击的模拟信息(特定AIM 3)。由于预期转导的FasL+细胞在潜在的体内转译应用中可能是有毒的，我们将研究限制潜在的FasL毒性的技术，例如，在对HSCs产生耐受后，通过消除转导细胞(或其FasL表达)。一种新的转导FasL+细胞治疗方法以减少 在GVHD(Aim 1)和SAA(Aim 3)中攻击宿主细胞的效应淋巴细胞最终可能被用于SAA、PNH和其他疾病的移植，Aim 1概述了一项潜在的临床试验。此外，我们对同种异体免疫细胞中的凋亡通路的机制研究将增加关于介导GVHD(和SAA)的效应细胞中Fas通路的基础的信息，这反过来将增加对(A)同种免疫反应、(B)逃避免疫监视的血液恶性肿瘤和(C)移植器官(或多能干细胞)生物学中死亡途径的理解。在具体目标2中，项目1、2和4将合作研究Fas通路在SANPNH患者HSCs病理生理学中的潜在作用。具体目标1：设计FasL+宿主DC或HSCs，选择性杀伤GVHD的细胞效应。目的2：探讨Fas通路在SAA和PNH发病机制中的作用。目的3：探讨FasL+HSCs是否选择性杀伤SAA自体抗HSC CTL。

The ability to stably transduce lympho-hematopoietic stem-progenitor cells (HSCs) allows us to genetically engineer HSCs and their progeny to serve as improved cellular tools to treat disease and complications. In Specific Aim 1, we propose preclinical studies in mouse and human models to confirm the concept and elucidate the principal cellular and molecular mechanisms by which Fas ligand-transduced (FasL*) dendritic cells (DCs) or HSCs may selectively kill the T and NK cells that mediate GVHD. The results of Aim 1 will also provide modeling information on the application of transduced FasL+ cells to reduce immune attack against HSCs in severe aplastic anemia (SAA) (Specific Aim 3). Since it is expected that transduced FasL+ cells may be toxic in potential future translational in vivo applications, we will investigate technologies to limit potential FasL toxicity, eg by eliminating the transduced cells (or their FasL expression) after tolerance to HSCs has been generated. A novel transduced FasL+ cell therapy approach to reduce effector lymphocytes attacking host cells in GVHD (Aim 1) and SAA (Aim 3) may eventually be used in transplants for SAA, PNH and other diseases, and a potential clinical trial is outlined in Aim 1. In addition, our accompanying mechanistic studies on apoptotic pathways in alloimmune cells will increase information on the fundamentals of the Fas pathway in the effector cells mediating GVHD (and SAA), which in turn, should increase understanding of death pathways in the biology of (a) alloimmune responses, (b) hematologic malignancies that evade immune surveillance, and (c) transplanted organs (or pluripotent stem cells). In Specific Aim 2, Projects 1, 2 and 4 will cooperate to investigate the potential role of the Fas pathway in the pathophysiology of HSCs from SANPNH patients. Specific Aim 1: To engineer FasL+ host DCs or HSCs to selectively kill the cellular effectors of GVHD. Specific Aim 2: To investigate the role of the Fas pathway in the pathogenesis of SAA and PNH. Specific Aim 3: To investigate whether FasL+ HSCs selectively kill autologous anti-HSC CTLs in SAA.