Transduction of Psychological Stress into Systematic Inflammation by Mitochondrial DNA Signaling

项目总结 全身性炎症被认为是心理压力对健康造成破坏性影响的原因之一。在 实验室环境下，单一的急性社会评价应激导致PRO-2延迟升高。 健康成人中的炎性细胞因子。然而，心理压力产生的生物学机制 转化为炎症的机制还不是很清楚。一种已知的导致压力的细胞成分 信号是线粒体--一种源自细菌的细胞器，具有自己的基因组，即线粒体DNA (MtDNA)。最近的证据表明，各种应激源诱导线粒体释放- 衍生的信号分子，或有丝分裂素。丝裂原在系统中传播并调节中枢生理 过程，包括免疫细胞功能和促炎细胞因子的产生。一个关键的有丝分裂素 是循环中的无细胞线粒体DNA(ccf-mtdna)，是线粒体排出mtdna的产物。 通过Toll样受体9(TLR-9)，在动物和人类中导致促炎细胞因子的产生 细胞。我们的初步数据显示，ccf-mtdna的释放是强烈诱导的，而不是ccf-核dna。 在人类经历了短暂的实验性心理压力之后。因此，我们认为CCF-mtDNA可能是一种 在应激-炎症级联反应中缺失了一环。同时，对细胞系统进行成像和分子研究 提示CCF-mtDNA可能由主要的神经内分泌应激介质迅速诱导，包括 糖皮质激素。这项建议将使用实验性的社会评估压力任务，与 控制每个参与者的无应激访问，绘制CCF-mtDNA和CCF-mtDNA中反应和恢复的动力学图 健康女性和男性的其他压力调节剂。目标1将确定：i)CCF的大小和动力学- 线粒体DNA释放；ii)这种反应相对于核DNA的特异性；iii)检查潜在的性别 在这一过程中的差异；以及iv)统计检验CCF-mtDNA作为随后PRO增加的中介。 炎性细胞因子。在目标2中，细胞和分子研究将确定：i)原发的 糖皮质激素和儿茶酚胺应激激素足以触发原发性CCF-mtDNA的释放 人培养细胞和分离的白细胞；ii)活细胞mtDNA对应激反应的图像 信号；以及iii)记录有助于CCF-mtDNA释放的mtDNA结构的物理变化。最后， 目的3建立：i)峰值CCF-mtDNA血清中CCF-mtDNA激活细胞因子产生的能力。 靶细胞；ii)人血清中CCF-mtDNA的结构形式和可获得性(来自Aim 1)；以及iii) 依赖TLR-9进行免疫激活。总体而言，这些研究将为 线粒体介导的人类应激转化为炎症的新机制。结果来自 这项工作将确定新的潜在目标，以改善与压力相关的心理健康和炎症性疾病。

PROJECT SUMMARY Systemic inflammation is believed to contribute to the damaging health effects of psychological stress. In the laboratory setting, a single acute bout of socioevaluative stress leads to a delayed elevation of pro- inflammatory cytokines in healthy adults. However, the biological mechanisms by which psychological stress is transduced into inflammation is not well understood. A cellular component known to contribute to stress signaling is the mitochondrion – a bacteria-derived organelle with its own genome, the mitochondrial DNA (mtDNA). Recent evidence has demonstrated that various stressors induce the release of mitochondria- derived signaling molecules, or mitokines. Mitokines travel systemically and modulate central physiological processes, including immune cell function and the production of pro-inflammatory cytokines. One key mitokine is circulating cell-free mtDNA (ccf-mtDNA), which arises from mitochondrial extrusion of mtDNA, is recognized by the toll-like receptor 9 (TLR-9), and leads to pro-inflammatory cytokine production in animal and human cells. Our preliminary data showed that ccf-mtDNA release, but not ccf-nuclear DNA, is acutely induced following a brief experimental psychological stress in humans. Thus, we suggest that ccf-mtDNA may be a missing link in the stress-inflammation cascade. In parallel, imaging and molecular studies on cellular systems suggests that ccf-mtDNA may be rapidly induced by primary neuroendocrine stress mediators, including glucocorticoids. This proposal will use an experimental socio-evaluative stress task, counterbalanced with a control no-stress visit for each participant, to map the kinetics of reactivity and recovery in ccf-mtDNA and other stress mediators in healthy women and men. Aim 1 will establish: i) the magnitude and kinetics of ccf- mtDNA release; ii) the specificity of this response compared to nuclear DNA; iii) examine potential sex differences in this process; and iv) statistically test ccf-mtDNA as a mediator of the subsequent increase in pro- inflammatory cytokines. In Aim 2, cellular and molecular studies will determine: i) whether primary glucocorticoid and catecholamine stress hormones are sufficient to trigger ccf-mtDNA release in primary human cultured cells and isolated leukocytes; ii) image in living cells mtDNA release in response to stress signaling; and iii) document physical changes in mtDNA structure that contribute to ccf-mtDNA release. Finally, Aim 3 will establish: i) the capacity of ccf-mtDNA from peak ccf-mtDNA serum to activate cytokine production in target cells; ii) the structural form and accessibility of ccf-mtDNA in human serum (from Aim 1); and iii) the dependency on TLR-9 for immune activation. Overall, these studies will contribute mechanistic evidence for a novel mitochondria-mediated mechanisms for transducing stress into inflammation in humans. Outcomes from this work will identify new potential targets to improve stress-related mental health and inflammatory disorders.