Coordination of Pathophysiologic endothelial cell signaling by ROS

细胞内钙稳态异常与心血管疾病（CVD）有关。 导致内皮功能障碍。Ca2+作为第二信使， 几种细胞功能。尽管现有证据表明Ca2+信号传导与内皮细胞之间存在联系， 尽管血管疾病的发生与功能障碍有关，但血管疾病发展的潜在机制仍不完全清楚。 除了Ca2+，活性氧也与内皮细胞（EC）功能障碍有关。一 越来越多的人认识到，线粒体Ca2+水平升高与后代之间存在联系， 线粒体活性氧（mROS）在心血管疾病中的作用。线粒体形态胞浆 Ca2+通过单向转运体和转运体螯合Ca2+来传递信号。然而，两者之间的因果关系 线粒体Ca2+超载和mROS的产生在EC功能障碍的背景下知之甚少。 最近鉴定的线粒体Ca 2+单向转运体复合物分子MCU和MICU1显示出调节 线粒体Ca2+摄取，然而这些分子在内皮功能中的病理生理作用 尚未被研究。我们的新发现表明，MICU1通过以下方式控制线粒体Ca2+的基础积累： 调节MCU。此外，MICU 1的沉默促进组成性线粒体Ca 2+过载， 随后升高mROS并使细胞对凋亡刺激物敏感。因此，我们的中心假设是 MICU1门控MCU孔活性，限制基础线粒体Ca2+积累和ROS 以保持血管的完整性。这个假设是基于我们最近的 出版在Cell该假设将使用分子和细胞生物学，生物化学和生物化学的组合进行测试。 和先进的成像技术，原代内皮细胞，转基因动物和样本， 患有冠状动脉疾病人类受试者。我们的建议将通过三个具体目标来解决这些问题： 描述MICU 1在EC线粒体Ca 2+稳态中的功能作用2）研究MICU 1在EC线粒体Ca 2+稳态中的作用。 EC信号传导和功能，以及3）研究MICU 1在病理生理条件下EC生物学中的作用。 条件重要的是，我们的研究将揭示MICU1在线粒体Ca2+稳态中的作用 和mROS的产生。这些研究的预期结果将大大 通过阐明MICU1在限制线粒体Ca2+负荷中发挥核心作用，转移EC信号传导的焦点 和氧化信号。预计这些发现将通过推进油田开发产生直接影响 EC Ca2+信号传导和氧化应激的信息将提供新的靶点的可能性很大 用于CVD的治疗干预。

Aberrant intracellular calcium ([Ca2+]i) homeostasis has been implicated in cardiovascular diseases (CVD) which contributes to endothelial dysfunction. Ca2+ acts as a second messenger and is known to regulate several cell functions. Despite the available evidence of a link between Ca2+ signaling and endothelial dysfunction, mechanisms underlying the development of vascular disease remain incompletely understood. Besides Ca2+, reactive oxygen species have also been implicated in endothelial cell (EC) dysfunction. A growing recognition exists of a link between elevated levels of mitochondrial Ca2+ and subsequent generation of mitochondrial reactive oxygen species (mROS) in cardiovascular diseases. Mitochondria shape cytosolic Ca2+ signals by sequestering Ca2+ through uniporter and transporters. Nevertheless, the causal link between mitochondrial Ca2+ overload and mROS production is poorly understood in the context of EC dysfunction. Recently identified mitochondrial Ca2+ uniporter complex molecules MCU and MICU1 are shown to regulate the mitochondrial Ca2+ uptake, however the pathophysiological role of these molecules in endothelial function has not been studied. Our new findings show that MICU1 gates the basal mitochondrial Ca2+ accumulation by regulating MCU. Further, silencing of MICU1 facilitates constitutive mitochondrial Ca2+ overload which subsequently elevates mROS and sensitizes cells to apoptotic stimuli. Accordingly, our central hypothesis is that MICU1 gates MCU pore activity limiting basal mitochondrial Ca2+ accumulation and ROS overproduction to preserve vascular integrity. The hypothesis was formulated based on our recent publication in Cell. The hypothesis will be tested using combination of molecular and cell biology, biochemical and advanced imaging technology, primary endothelial cells, genetically-modified animals and samples from human subject with coronary artery disease. Our proposal will address these issues via three specific aims: 1) Characterize the functional role of MICU1 in EC mitochondrial Ca2+ homeostasis 2) Study the role of MICU1 in EC signaling and function, and 3) Investigate the role of MICU1 in EC biology under pathophysiological conditions. Importantly, our investigations will uncover the role of MICU1 in mitochondrial Ca2+ homeostasis and mROS production in vascular endothelium. The expected outcomes from these studies will significantly shift the focus of EC signaling by elucidating that MICU1 plays a central role in limiting mitochondrial Ca2+ load and oxidative signaling. Such findings are expected to have an immediate impact through advancing the fields of EC Ca2+ signaling and oxidative stress with a strong likelihood that the information will provide new targets for therapeutic interventions in CVD.