Functional, structural and metabolic consequences of ionic dysbalance in stroke

中风中离子失衡的功能、结构和代谢后果

• 批准号: 411456372
• 负责人: Professor Dr. Gabor Petzold
• 金额: --
• 依托单位: Klinik und Poliklinik für Neurologie
• 依托单位国家: 德国
• 项目类别: Research Units
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/411456372?language=en
• 关键词: Functional; structural; metabolic; consequences; ionic

Ischemic stroke is a leading cause of death and disability worldwide. There is a pressing need to better understand and therapeutically leverage the molecular and cellular changes contributing to stroke pathogenesis. Spreading depolarization (SD) waves represent a particularly relevant disease mechanism during acute stroke. These waves, which are triggered in the hypoxic area by an extracellular overload of glutamate and potassium, can propagate through the ischemic area and into healthy tissue. We and others have shown that SDs are accompanied by strong elevations of the intracellular calcium concentration in astrocytes and neurons, which can increase cellular damage by triggering glutamate release. Based on our data from the first funding period, we will investigate several pathways relevant for calcium and sodium dysbalance and glutamate release during ischemic SDs. First, we will investigate the role of the glutamate transporter GLT1 in the post-acute phase after stroke, based on our preliminary data that astroglial GLT1 is downregulated after transient focal ischemia. We will determine the consequences of this downregulation for calcium and sodium signaling as well as extracellular glutamate, using in vivo two-photon microscopy of fluorescent reporters, and whether pharmacological upregulation of GLT1 with ceftriaxone can counteract these effects. Second, we will investigate the role of astroglial cell swelling mediated by volume- regulated anion channels (VRAC) in glutamate release during ischemic SDs, using mice in which the VRAC subunit SWELL1 has been specifically deleted in astrocytes. Third, we will further investigate preliminary data that the frequency of calcium microdomains in astrocytes is increased after ischemic SDs. Specifically, we will determine if these signals co-localize with mitochondria, and what the roles of mitochondrial sodium-calcium exchanger are in these calcium changes. Moreover, we will also investigate the consequences of these changes for glutamate release and mitochondrial morphology and energy metabolism. Finally, we will build on previous work that transient receptor vanilloid 4 (TRPV4) channels contribute to calcium influx into astrocytes and neurons and subsequent extracellular glutamate accumulation during ischemic SDs, to investigate the role of TRPV4 in sodium changes during SDs. In all of these projects, we will also determine SD threshold, infarct volume and motor outcome. Together, our experiments will identify novel pathways relevant for calcium and sodium overload and glutamate release during SDs after stroke, and may lead to the development of new translational treatment strategies to attenuate these deleterious events.

缺血性中风是全世界死亡和残疾的主要原因。迫切需要更好地理解和治疗性地利用导致中风发病机制的分子和细胞变化。传播的去极化（SD）波代表了急性中风期间特别相关的疾病机制。这些波是由细胞外谷氨酸和钾超载在缺氧区域触发的，可以通过缺血区域传播到健康组织。我们和其他人已经证明，SDs 伴随着星形胶质细胞和神经元细胞内钙浓度的强烈升高，这可以通过触发谷氨酸释放来增加细胞损伤。根据我们第一个资助期的数据，我们将研究与缺血性 SD 期间钙和钠失衡以及谷氨酸释放相关的几种途径。首先，我们将根据短暂性局灶性缺血后星形胶质细胞 GLT1 下调的初步数据，研究谷氨酸转运蛋白 GLT1 在中风后急性期中的作用。我们将使用荧光报告基因的体内双光子显微镜确定这种钙和钠信号传导以及细胞外谷氨酸下调的后果，以及头孢曲松对 GLT1 的药理学上调是否可以抵消这些影响。其次，我们将使用星形胶质细胞中 VRAC 亚基 SWELL1 已被特异性删除的小鼠，研究体积调节阴离子通道 (VRAC) 介导的星形胶质细胞肿胀在缺血性 SD 期间谷氨酸释放中的作用。第三，我们将进一步研究缺血性 SD 后星形胶质细胞中钙微区频率增加的初步数据。具体来说，我们将确定这些信号是否与线粒体共定位，以及线粒体钠钙交换器在这些钙变化中的作用。此外，我们还将研究这些变化对谷氨酸释放、线粒体形态和能量代谢的影响。最后，我们将在先前研究的基础上，研究瞬时受体香草酸 4 (TRPV4) 通道在缺血性 SD 期间促进钙流入星形胶质细胞和神经元以及随后的细胞外谷氨酸积累，以研究 TRPV4 在 SD 期间钠变化中的作用。在所有这些项目中，我们还将确定 SD 阈值、梗塞体积和运动结果。总之，我们的实验将确定与中风后 SD 期间钙和钠超载以及谷氨酸释放相关的新途径，并可能导致开发新的转化治疗策略以减轻这些有害事件。