Heat shock proteins in the nervous system

作为对应激刺激的响应，细胞激活一种高度保守的热休克反应，在这种反应中诱导出一系列在细胞修复和保护中发挥作用的应激蛋白(称为热休克蛋白或热休克蛋白)。我们以前的研究表明，这种细胞应激反应是与生理相关的，因为热休克蛋白在神经系统对温度升高和组织损伤的反应是快速诱导的。热休克蛋白是一种“蛋白质修复剂”，可以提供一道防线，防止在细胞应激后和神经退行性疾病期间堆积的错误折叠、容易聚集的蛋白质。HSPA是一个多基因家族，包括由HSPA1A基因编码的应激诱导的Hsp70-1和由HSPA6编码的应激诱导的Hsp70B‘。这项研究提案的愿景是将细胞应激反应的神经生物学带入一个新时代。也就是说，在组织培养中生长的神经细胞中的细胞应激反应的实时成像，以及在完整的哺乳动物大脑中的高分辨率实时成像，重点是Hsp70B‘。我们的研究小组是目前唯一报道Hsp70B‘在神经系统中表达的实验室。2014年10月，我们报道了Hsp70B‘的一个新角色，这是Hsp70-1没有观察到的。在神经细胞从应激诱导的转录抑制中恢复的过程中，Hsp70B‘与核斑点的外围短暂地联系在一起，核斑点是转录的位置。我们现在将确定应激后的转录恢复是否依赖于Hsp70B‘的诱导，以及这种现象是否特定于神经细胞。通过旋转圆盘显微镜对培养的神经细胞中Hsp70的实时图像定位，以及通过多光子显微镜在完整的大脑中识别应力敏感的细胞内位置。这些研究将有助于实时分析神经系统中的细胞应激反应。我们的神经蛋白质错误折叠的新型多目标调节剂的神经保护功能将利用最新的多光子进展进入活着的大脑中的新分析领域。参加该计划的学员将受益于细胞应激反应的新方面的工作，以及在2009-2014年间获得的一系列先进技术，其中580万美元的CFI/ORF基础设施大奖授予多伦多斯卡伯勒大学生物科学系应激神经生物学中心。

In response to stressful stimuli, cells activate a highly conserved heat shock response in which a set of stress proteins (termed ‘heat shock proteins’ or ‘Hsps’) are induced that play roles in cellular repair and protection. Our previous studies have shown that this cellular stress response is physiologically relevant as Hsps are rapidly induced in the nervous system in response to temperature elevation and tissue injury. Hsps are ‘protein repair agents’ that provide a line of defense against misfolded, aggregation-prone proteins that accumulated following cellular stress and during neurodegenerative disorders. HSPA is a multigene family that includes i) stress-inducible Hsp70-1 encoded by the HSPA1A gene and ii) stress-inducible Hsp70B’ encoded by HSPA6 that has received comparatively little attention. The vision of this research proposal is to move the neurobiology of the cellular stress response into a new era. Namely, live imaging of the cellular stress response in neuronal cells grown in tissue culture and, beyond that, to high resolution live imaging in the intact mammalian brain, with a focus on Hsp70B’. Our research group is presently the only laboratory that has reported on expression of Hsp70B’ in neural systems. In October 2014, we reported a novel role of Hsp70B’ that is not observed for Hsp70-1. Hsp70B’ transiently associates with the periphery of nuclear speckles that are sites of transcription during the recovery of neuronal cells from stress-induced transcriptional inhibition. We will now determine if transcriptional recovery after stress is dependent on induction of Hsp70B’ and if the phenomenon is specific to neuronal cells. Stress-sensitive intracellular sites will be identified by live image localization of Hsp70s in cultured neuronal cells by spinning disk microscopy and in the intact brain by multiphoton microscopy. These studies will facilitate real time analysis of the cellular stress response in neural systems. Neuroprotective features of our novel multitarget modulators of neural protein misfolding will be moved into a new realm of analysis in the living brain using the latest multiphoton advances. Trainees participating in the program will benefit from working on novel aspects of the cellular stress response and from the array of advanced technology acquired over the period 2009-2014 with a major CFI/ORF infrastructure award of $5.8 million to the Center for the Neurobiology of Stress, Department of Biological Sciences, University of Toronto Scarborough.