Novel humanized mouse model developed from cord blood CD34 positive HSC and autologous iPS cell derived thymus

项目概要/摘要 人源化小鼠，即免疫缺陷小鼠，通过以下方式支持人类免疫系统的发育 人类造血干细胞（HSC）的植入在临床前变得越来越重要 工具。然而，HSC 植入 NSG 小鼠会导致 H2 限制性人类 T 细胞的发育， 不能与自体人类 HLA 表达、抗原呈递细胞和 B 细胞适当相互作用 外围。 NSG-HLA 转基因小鼠的诞生是为了解决这个问题，但是 HLA 的全部功能 特异性仅限于那些表达的并且 H2 限制的人类 T 细胞继续在 小鼠胸腺。人源化 NSG 小鼠中最强大的免疫系统是使用胎儿组织创建的， BLT（骨髓/肝脏/胸腺）模型。 BLT 模型的使用允许人类 T 细胞在 自体胸腺并产生强大的 HLA 限制性人类免疫系统。然而，一些人类T 细胞仍在小鼠胸腺中发育，并且受到 H2 限制，这使实验的解释变得混乱。在 此外，利用人类胎儿组织来制造人源化小鼠也因其有限的可用性而变得复杂。 由于对组织采购的担忧。为了提供基于胎儿组织的模型的替代方案， 我们建议利用通过人类细胞因子转基因杂交开发的新型无胸腺 NSG 小鼠品系 NSG 小鼠使用我们的无胸腺 NSG-Foxn1null（裸）小鼠原种并通过 CRISPR/Cas 直接靶向 Foxn1 我们的新 NSG 库存表达人类造血生长因子。我们将使用脐带血 iPS 细胞创建人类胸腺结构，支持 HLA 限制性人类 T 细胞的体内发育 源自自体脐带血 HSC 的细胞。对于这个多 PI、多学科团队项目，我们建议 三个目标：1) 生成并验证支持最佳植入的免疫缺陷小鼠的新模型 小鼠胸腺缺失情况下的 HSC 和人胸腺组织的功能； 2）生成并验证人类 iPS 细胞产生的胸腺上皮和类器官； 3）比较人体免疫系统产生的情况 在我们的新模型中使用 BLT 模型。我们的建议利用强大的新技术 创建新的人源化小鼠模型，并建立在我们超过 25 年的生成、验证、 并分享人源化小鼠的新模型。我们相信，我们的创新方法与我们的 多学科协作团队将确保这一急需的临床前模型的开发 不依赖使用人类胎儿组织的人源化小鼠。此外，舒尔茨博士在杰克逊 将开发这些小鼠模型的实验室，以促进它们快速分发给科学界 社区，并使我们处于独特的地位，以实现该计划公告中的既定目标。

PROJECT SUMMARY/ABSTRACT Humanized mice, i.e., immunodeficient mice that support the development of human immune systems by engraftment with human hematopoietic stem cells (HSCs) have become increasingly important preclinical tools. However, HSC engraftment of NSG mice results in the development of H2-restricted human T cells that cannot interact appropriately with autologous human HLA-expressing, antigen-presenting cells and B cells in the periphery. NSG-HLA transgenic mice have been generated to address this, but the repertoire of HLA specificities is restricted to only those expressed and H2-restricted human T cells continue to be generated in the murine thymus. The most robust immune system in humanized NSG mice is created using fetal tissues, the BLT (bone marrow/liver/thymus) model. Use of the BLT model permits human T cell development on an autologous thymus and generates robust HLA-restricted human immune systems. However, some human T cells still develop in the murine thymus and are H2-restricted, confounding interpretation of the experiments. In addition, the use of human fetal tissue to create humanized mice is complicated by its limited availability and by concerns surrounding procurement of the tissues. To provide an alternative to fetal tissue-based models, we propose to utilize novel athymic NSG mouse strains developed by crosses of human cytokine trangenic NSG mice with our athymic NSG-Foxn1null (nude) mouse stock and by CRISPR/Cas targeting Foxn1 directly in our new NSG stocks expressing human hematopoietic growth factors. We will use umbilical cord blood-derived iPS cells to create human thymus structures that will support in vivo development of HLA-restricted human T cells derived from autologous cord blood HSCs. For this multi-PI, multi-disciplinary team project, we propose three Aims: 1) Generate and validate new models of immunodeficient mice that support optimal engraftment of HSCs and function of human thymic tissues in the absence of murine thymus; 2) Generate and validate human thymic epithelium and organoids generated from iPS cells; 3) Compare the human immune system generated in our new models with the BLT model. Our proposal takes advantage of powerful new technologies for creating new models of humanized mice, and builds on our >25 year track record for generating, validating, and sharing novel models of humanized mice. We believe that our innovative approaches, combined with our multi-disciplinary collaborative team will ensure the development of this much-needed preclinical model of humanized mice that does not rely on use of human fetal tissues. Furthermore, Dr. Shultz is at The Jackson Laboratory where these mouse models will be developed, facilitating their rapid distribution to the scientific community and uniquely positioning us to achieve the stated goals of this program announcement.