The Role of Mitochondrial DNA in Innate Immune Activation after Sudden CardiacArrest

摘要 心脏骤停在住院的退伍军人中非常普遍，并导致压倒性的死亡率。 不幸的是，没有药物治疗已被证明可以可靠地增加生存后， 心脏骤停心脏骤停的幸存者通常具有全身器官损伤， 在医院的重症监护室。这些患者中的大多数都有心脏功能下降，四分之一的人 这些病人死于心源性休克。心脏炎症被认为有助于这种功能障碍， 可能是由损伤相关分子模式（DAMP）驱动的。一个突出的DAMP是线粒体 DNA（mtDNA）。我们实验室的初步工作表明，旨在保持mtDNA完整性的策略， 包括线粒体转录因子A（TFAM）的过表达，对心脏功能有保护作用， 小鼠心脏骤停模型。TFAM是一个核基因，调节mtDNA的表达，包装， 和拷贝数，并且已知在许多心脏病模型中具有保护作用。 我的首要假设是，心脏骤停引起的缺血再灌注损伤导致mtDNA释放， 这会触发心脏的炎症反应，并且这种反应取决于cGAS/STING 发信号。为了探索这个假设，我将追求三个具体目标。在目标1中，我将探讨 在体外使用显微镜检查释放mtDNA，并在体内模型中证实了这些变化， 心脏骤停在目标2中，我将使用转基因小鼠模型来操纵TFAM以影响mtDNA 释放和敲除STING信号传导，以探索mtDNA释放与 心脏骤停后的炎症在目标3中，我将描述心脏的炎症反应 在心脏骤停后，操纵cGAS/STING信号传导以评估cGAS/STING介导的 炎性变化。 总之，这些目标将评估心脏骤停后mtDNA释放的作用及其在 先天免疫信号，这可能会指导未来的人类研究疗法。这项工作将支持我的目标 过渡到一个独立的研究生涯作为一个医生，科学家研究线粒体的变化， 心血管疾病这笔赠款将支持在两个继续研究和职业发展， 匹兹堡退伍军人管理医院和匹兹堡大学，包括课程，职业生涯 导师，和科学培训，旨在过渡到独立作为一个医生科学家在 退伍军人管理系统。

ABSTRACT Sudden cardiac arrest is highly prevalent among hospitalized veterans and results in overwhelming mortality. Unfortunately, there are no pharmacologic therapies that have been shown to reliably increase survival after sudden cardiac arrest. Survivors of sudden cardiac arrest typically have systemic organ damage requiring intensive care in the hospital. The majority of these patients have reduced cardiac function and one quarter of these patients die from cardiogenic shock. Cardiac inflammation is thought to contribute to this dysfunction and is likely driven by damage associated molecular patterns (DAMPs). One prominent DAMP is mitochondrial DNA (mtDNA). Preliminary work in our lab has shown that strategies aimed at preserving mtDNA integrity, including overexpression of mitochondrial transcription factor A (TFAM), are protective to cardiac function in a mouse model of sudden cardiac arrest. TFAM is a nuclear gene that regulates mtDNA expression, packaging, and copy number and is known to be protective in a number of heart disease models. My overarching hypothesis is that ischemia-reperfusion injury from cardiac arrest results in mtDNA release, which triggers an inflammatory response in the heart, and that this response is dependent upon cGAS/STING signaling. To explore this hypothesis, I will pursue three specific aims. In Aim 1, I will explore the mechanism by which mtDNA is released using microscopy in vitro and confirm these changes in an in vivo model of sudden cardiac arrest. In Aim 2, I will use transgenic mouse models to manipulate TFAM to affect mtDNA release and also knock-out STING signaling to explore the relationship between mtDNA release and inflammation after sudden cardiac arrest. In Aim 3, I will characterize the inflammatory response in the heart after sudden cardiac arrest and manipulate cGAS/STING signaling to evaluate cGAS/STING mediated inflammatory changes. Together, these aims will evaluate the role of mtDNA release following sudden cardiac arrest and its role in innate immune signaling, which may guide future therapies for human studies. This work will support my goal of transitioning into an independent research career as a physician-scientist studying mitochondrial changes in cardiovascular disease. This grant will support continued research and career development at both the Veterans Administration Hospital in Pittsburgh and the University of Pittsburgh, including coursework, career mentorship, and scientific training aimed at transitioning to independence as a physician scientist in the Veterans Administration system.