Circadian regulation of cancer therapy-associated neuroinflammation

癌症治疗的最新进展提高了许多儿童和成人癌症的存活率。通过 到2023年，超过2000万癌症幸存者将生活在美国。不幸的是，其中绝大多数 个体将表现出一些持续性神经功能缺陷的迹象，临床上称为癌症治疗- 相关认知障碍(CRCI)。这些损伤包括记忆、学习、注意力、 执行功能、信息处理、语言和多任务处理。尽管有无数可疑的原因 CRCI的主要共性之一是癌症治疗后持续的神经炎性状态。多么 这种持续的神经炎症是由媒介引起的，这仍然是我们对潜在的 CRCI的生物学。我们之前在临床前小鼠模型中的工作表明，通常使用的 化疗药物甲氨蝶呤(MTX)诱导的三神经胶质细胞失调依赖于直接 激活小胶质细胞，这是中枢神经系统的常驻免疫细胞。甲氨蝶呤全身给药 导致持续的小胶质细胞PAN激活，促进星形胶质细胞的反应性和降低OPC密度 分化为形成髓鞘的少突胶质细胞，导致髓鞘变薄。甲氨蝶呤诱发的畸变率 髓鞘形成导致与CRCI相关的持续性认知障碍，包括短期内的减少 治疗后记忆力和注意力最长可达六个月。我们实验室的初步数据表明，这 小胶质细胞的激活，以及随之而来的少突胶质细胞系细胞的失调，是一天中的时间依赖的， 提示CRCI相关的持续小胶质细胞活化和临床缺陷可能受到调节。 以昼夜节律的方式，因此容易受时钟调整的影响。这项提案的目标是确定 如果MTX化疗导致小胶质细胞转录组的内在变化并改变结构或功能 维持与CRCI相关的小胶质细胞的激活。我们的中心假设是 化疗诱导的慢性神经炎由小胶质细胞的昼夜调节和 BBB。我们验证这一假设的方法是在体外和体内将小胶质细胞暴露于MTX化疗 并分析分离的小胶质细胞和血脑屏障内皮细胞的转录图谱， 以及评估血脑屏障的渗透性和完整性。这种方法的基本原理是，从 这些结果将有助于从机制上理解生物多样性的内在和微环境调节因素。 癌症治疗后的神经炎性小胶质细胞。这项建议完成后，我们预计将拥有 确定了昼夜节律如何决定小胶质细胞对化疗的激活。仍有一项紧急情况 需要确定神经炎症调节持续性神经性疾病的潜在机制 癌症治疗的临床前模型中CRCI的失调。在缺乏这样的知识的情况下，有效 旨在减轻神经炎症的治疗策略将仍然难以捉摸，随后将持续下去 神经缺陷将继续成为癌症幸存者和我们医疗体系的实质性负担。

Recent advances in cancer therapy have increased survivability of numerous pediatric and adult cancers. By 2023, over 20 million cancer survivors will live in the United States. Unfortunately, the vast majority of these individuals will exhibit some indication of sustained neurological deficiency, clinically called cancer therapy- related cognitive impairment (CRCI). These impairments include deficits in memory, learning, attention, executive function, information processing, language, and multitasking. Despite the myriad suspected causes of CRCI, one of the main commonalities is a persistent neuroinflammatory state following cancer treatment. How this sustained neuroinflammation is mediated remains a critical gap in our understanding of the underlying biology of CRCI. Our previous work in a preclinical mouse model demonstrated that the commonly used chemotherapeutic agent, methotrexate (MTX), induces tri-glial dysregulation that is dependent on the direct activation of microglia, the resident immune cells of the central nervous system. Systemic MTX administration results in persistent microglial pan activation which promotes astrocyte reactivity and decreased OPC density and differentiation into myelin-forming oligodendrocytes, leading to thinner myelin. MTX-induced aberrant myelination causes persistent cognitive deficits associated with CRCI, including decrements in short-term memory and attention for up to six months post-treatment. Preliminary data from our lab demonstrates that this microglial activation, and consequent dysregulation of oligodendrocyte lineage cells, is time-of-day dependent, suggesting that the sustained microglial activation and clinical deficiency associated with CRCI may be regulated in a circadian manner and thus susceptible to chronomodulation. The objective of this proposal is to determine if MTX chemotherapy drives intrinsic changes to the microglial transcriptome and alters the structure or function of the BBB to sustain the activation of microglia associated with CRCI. Our central hypothesis is that chemotherapy-induced chronic neuroinflammation is modulated by circadian regulation of microglia and the BBB. Our approach to testing this hypothesis is to expose microglia in vitro and in vivo to MTX chemotherapy at different circadian phases and analyze the transcriptional profile of isolated microglia and BBB endothelial cells, as well as assess BBB permeability and integrity. The rationale for this approach is that information gleaned from the results will contribute mechanistic understanding into the intrinsic and microenvironmental modulators of neuroinflammatory microglia following cancer therapy. Upon completion of this proposal, we expect to have identified how circadian modulation dictates microglial activation to chemotherapy. There remains an urgent need to define the underlying mechanisms of neuroinflammation mediating the persistent neurological dysregulation in CRCI in preclinical models of cancer therapy. In the absence of such knowledge, effective therapeutic strategies aimed at mitigating neuroinflammation will remain elusive and subsequent sustained neurological deficits will continue to be a substantive burden to cancer survivors and our healthcare system.