cGAS-mediated glial responses to DNA damage: A pilot study

摘要 基因组不稳定是癌症和年龄相关疾病的主要驱动力。而当 DNA损伤反应长期以来被认为是调节基因组完整性和细胞命运的因素， 越来越多的证据表明，基因组的不稳定也会引发炎症反应。 最近的研究为这种反应的潜在机制提供了洞察力 随着细胞内DNA传感器、环状GMP-AMP合成酶的研究 (CGAS)，可以在将DNA损伤与先天性免疫联系起来的过程中发挥关键作用。有趣的是，我们的 研究小组最近描述了人类小胶质细胞和星形胶质细胞 对外来胞浆双链DNA的反应，我们证明了人类神经胶质细胞 在静息和激活状态下，cGAS蛋白的表达水平很高。 此外，我们还展示了这些细胞类型结构性地表达关键下游 CGAS接头蛋白，干扰素基因刺激物(STING)。在这项R03先导研究中， 我们将开始检验cGAS-STING通路检测细胞质的假设 基因毒性应激后小胶质细胞和/或星形胶质细胞中的DNA并启动胶质细胞自体 炎症反应。该项目源于两家公司之间的一项新合作 在DNA损伤研究方面具有互补专业知识的经验丰富的调查人员 修复机制和神经胶质天然免疫感受器分子。在这些初步报告中 研究，我们将确定基因组DNA损伤是否会导致微核形成 以及培养的胶质细胞中cGAS产物cGAMP水平的上升，我们将 将这种反应与自身炎症介质的产生或 潜在的抗肿瘤因子，如I型干扰素。此外，我们将直接 评估cGAS-STING通路在神经胶质细胞对DNA反应中的相对重要性 药物抑制和/或CRISPR/Cas9基因组编辑后的损害。这个 拟议的试验性R03研究是这一新研究方向的重要第一步，并 将为更全面地调查委员会的作用提供坚实的理由 CGAS-STING通路在中枢神经系统细胞衰老和肿瘤中的作用 将寻求机制支持。

Abstract Genomic instability is a major driving force for cancer and age-related diseases. While DNA damage responses were long thought to regulate genome integrity and cell fates, evidence is accumulating that genomic instability also triggers inflammatory responses. Recent studies have provided insight into the mechanisms underlying such responses with the demonstration that the cytosolic DNA sensor, cyclic GMP-AMP synthase (cGAS), can play a key role in linking DNA damage to innate immunity. Interestingly, our research team has recently described the ability of human microglia and astrocytes to respond to foreign cytosolic double-stranded DNA and we demonstrated that human glia show robust levels of cGAS protein expression at rest and following activation. Furthermore, we showed these cell types constitutively express the critical downstream cGAS adaptor protein, stimulator of interferon genes (STING). In this R03 pilot study, we will begin to test the hypothesis that the cGAS-STING pathway detects cytoplasmic DNA in microglia and/or astrocytes after genotoxic stress and initiates glial auto- inflammatory responses. This project stems from a new collaboration between two experienced investigators with complementary expertise in the study of DNA damage repair mechanisms and glial innate immune sensor molecules. In these preliminary studies, we will determine whether genomic DNA damage elicits micronuclei formation and an elevation in the level of the cGAS product cGAMP in cultured glia, and we will correlate such responses with the production of auto-inflammatory mediators or potentially anti-tumor factors such as type I interferon. Furthermore, we will directly assess the relative importance of the cGAS-STING pathway in glial responses to DNA damage following pharmacological inhibition and/or CRISPR/cas9 genome editing. The proposed pilot R03 studies are an important first step in this new research direction and will provide a solid rationale for a more comprehensive investigation into the role of the cGAS-STING pathway in CNS cellular senescence and cancer for which future R01 mechanism support will be sought.