Coordination of Pathophysiologic endothelial cell signaling by ROS

细胞内钙([Ca+]i)稳态异常与心血管疾病有关 这会导致内皮功能障碍。Ca2+起第二信使的作用，已知它能调节 几种细胞功能。尽管有证据表明钙信号和内皮细胞之间存在联系 功能障碍，血管疾病发展的潜在机制仍然不完全清楚。 除了Ca~(2+)外，内皮细胞(EC)功能障碍也与活性氧有关。一个 越来越多的人认识到线粒体Ca~(2+)水平升高与后代之间的联系 线粒体活性氧物种(MRO)在心血管疾病中的作用。线粒体形状胞质 Ca~(2+)通过单转运体和转运体隔离钙信号。然而，两者之间的因果联系 在EC功能障碍的背景下，线粒体钙超载和MROs的产生还知之甚少。 新近发现的线粒体钙单转运蛋白复合体分子MCU和MICU1具有调节作用 线粒体钙摄取，然而，这些分子在内皮功能中的病理生理作用 还没有被研究过。我们的新发现表明，MICU1通过以下途径关闭线粒体基础钙积聚 调节MCU。此外，沉默MICU1促进了结构性线粒体钙超载，这 随后提高MRO，并使细胞对凋亡刺激敏感。因此，我们的中心假设是 MICU1门控MCU孔道活性限制线粒体基础钙积聚和ROS 生产过剩以保持血管的完整性。这一假设是基于我们最近提出的 在单元格中发布。这一假说将通过结合分子和细胞生物学、生化 和先进的成像技术，原代内皮细胞，转基因动物和来自 患有冠心病的人类受试者。我们的提案将通过三个具体目标解决这些问题：1) MICU1在EC线粒体钙稳态中的作用2)研究MICU1在EC线粒体钙稳态中的作用 3)探讨MICU1在EC病理生理生物学中的作用 条件。重要的是，我们的研究将揭示MICU1在线粒体钙稳态中的作用 血管内皮细胞产生MRO。这些研究的预期结果将显著 通过阐明MICU1在限制线粒体钙负荷中的中心作用来转移EC信号转导的焦点 和氧化信号。预计这些发现将通过推动油田的发展产生立竿见影的影响 EC钙信号与氧化应激的关系，这些信息很可能会提供新的靶点 用于心血管疾病的治疗干预。

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.