Elucidating the distinct roles of T cell-polarized microglia in glioblastoma suppression and progression

项目摘要/摘要 胶质母细胞瘤是一种IV级弥漫性星形细胞瘤，是成人脑癌中最致命和最常见的形式。 护理标准将生存期延长了大约1-18个月，老年人享受的福利最少 患者(&gt；70岁)。新形式的基于免疫的治疗，包括免疫检查点抑制剂(ICI)，可能会转向 在原发和复发的胶质母细胞瘤治疗中的角落。不幸的是，到目前为止还没有临床试验表明 对这些患者的生存或免疫参与都有重大好处。最近的发现表明，胶质瘤 窝藏多种相互交织的免疫抑制细胞来源，抑制ICI启动的反应。 因此，一种解决方案可能是不仅通过阻断CTLA-4和PD-4等检查点来增强效应器T细胞- 1，但也针对胶质母细胞瘤的免疫抑制利基，其中最大的是胶质瘤- 相关的小胶质细胞和巨噬细胞(GAMs)。事实上，GAMs是一个非常有吸引力的目标，而且一直是 通过抑制CSF1R(PLX3397)在临床前和临床研究中耗尽。然而，这种方法产生了 模型中出现混合反应，患者中没有反应。另一条路可能是对gam重新编程，但我们缺乏 对促进抗肿瘤游戏的途径的洞察。因此，鉴定细胞和分子 调节促肿瘤和抗肿瘤的GAM状态是解锁新治疗途径的下一步。近期工作 由Kaech实验室发现，CTLA-4阻断在原位小鼠胶质母细胞瘤模型中减少了调控 T细胞(Treg)浸润，Th1辅助细胞浸润增加，小胶质细胞暴露于Th1细胞来源的IFNG 被重新编程为抗原提呈(MHCII+)、肿瘤吞噬(AXL+/MER+)状态；协同， 这些效应显著提高了存活率。这项提案将研究GAMs，特别是大脑如何 驻留的小胶质细胞，获得并维持不同的功能状态，假设Treg特异性信号 在胶质母细胞瘤进展过程中维持促肿瘤GAMs，而Th1T细胞诱导肿瘤杀伤GAMs 在ICI发起的有效响应期间。本文提出了两个具体的目标来验证这一假设。第一 AIM将使用单细胞空间转录转录技术来研究Tregs和Th1细胞是否是外部调节细胞 通过直接接触和/或分泌信号的GAM状态，以及这些相互作用轴是否存在于 人类胶质母细胞瘤。第二个目标将定义内在的Axl/mer和相关的调节GAM的途径 状态‘切换’。总之，这项工作将通过定义如何渗透来更好地向GAM目标干预提供信息 T细胞和GAM内在信号通路协调促肿瘤和抗肿瘤的动态生物学 GAM状态。本申请书概述了申请人提出的培训计划，其中包括多样化和 多学科研究指导，尖端和先进技术培训，以及 更广泛的科学技能，如协作和有效沟通。中概述的研究和培训 这项建议将使申请者做好准备，进行创新、严谨和有影响力的研究。

Project Summary/Abstract Glioblastoma is a grade IV diffuse astrocytoma, the deadliest and most common form of adult brain cancer. Standard of care extends survival by approximately 1-18 months, with the poorest benefits being seen by elderly patients (>70yrs). New forms of immune-based therapies, including immune checkpoint inhibitors (ICI), may turn the corner in treatments for primary and recurrent glioblastoma. Unfortunately, no clinical trial so far has shown major benefits in either survival or immune engagement for these patients. Recent findings suggest that gliomas harbor multiple and intertwined cellular sources of immune suppression that dampen ICI-initiated responses. Thus, one solution may be to not only enhance effector T cells by blocking checkpoints such as CTLA-4 and PD- 1, but to also target the immune suppressive niches in glioblastoma, the largest of which is comprised of glioma- associated microglia and macrophages (GAMs). In fact, GAMs are a highly attractive target and have been depleted in pre-clinical and clinical studies via CSF1R inhibition (PLX3397). This approach, however, yielded mixed responses in models and no response in patients. Another path may be to reprogram GAMs, but we lack insights into the pathways that promote anti-tumor GAMs. Therefore, identifying the cellular and molecular regulators of pro- and anti-tumor GAM states is the next step in unlocking new therapeutic avenues. Recent work by the Kaech lab showed that CTLA-4 blockade in orthotopic mouse models of glioblastoma reduced regulatory T cell (Treg) infiltration, increased ‘helper’ Th1 cell infiltration, and microglia exposed to Th1 cell-derived IFNg were reprogrammed into an antigen presenting (MHCII+), tumor-phagocytosing (AXL+/MER+) state; in concert, these effects significantly increased survival. This proposal will investigate how GAMs, especially the brain resident microglia, acquire and maintain distinct functional states with the hypothesis that Treg-specific signaling sustains tumor-promoting GAMs during glioblastoma progression while Th1 T cells induce tumor-killing GAMs during an effective ICI-initiated response. Two specific aims are proposed to interrogate this hypothesis. The first aim will employ single-cell spatial transcriptomics to address whether Tregs and Th1 cells are extrinsic regulators of GAM states through direct contact and/or secretory signaling, and whether these interaction axes exist in human glioblastoma. The second aim will define the intrinsic AXL/MER and related pathways regulating GAM state ‘switching’. In summary, this work will better inform GAM-targeting interventions by defining how infiltrating T cells and GAM-intrinsic signaling pathways coordinate the dynamic biology underlying pro- and anti-tumor GAM states. This application outlines the applicant’s proposed training plan, which includes diverse and multidisciplinary research mentorship, training in cutting-edge and advanced techniques, and development of broader scientific skills such as collaboration and effective communication. The research and training outlined in this proposal will prepare the applicant to conduct innovative, rigorous, and impactful research.