CAREER: Proteostasis to Allostasis: Integration of Cellular- and Organismal-level Stress Responses

应激事件会永久性地改变生物体的功能。成年人的同样情况也可以追溯到生命早期的事件。因此，了解生物体如何应对环境压力是至关重要的。然而，这在一定程度上是具有挑战性的，因为尽管对压力的反应已经在细胞和整个有机体水平上进行了研究，但科学家们还没有成功地在整个动物的压力和细胞后果之间建立起联系。该项目的目标是1)提高我们对压力反应在两个水平上的理解，以及2)批判性地评估压力反应是如何调节的。该项目还旨在提高阿拉巴马州农村地区的科学素养和基于探究的科学教育。首先，这个项目将有助于更全面地了解有机体如何应对压力，并将向初中生和高中生传授分子和整个动物层面的事件是如何相互联系的。其次，描述压力反应调节的模型已被应用于评估疾病风险因素，例如肥胖和社会经济地位。该项目将教育阿拉巴马州公立学校的学生肥胖、生活方式和饮食的后果，以及如何克服压力。最后，阿拉巴马州东南部的科学博览会项目的参与率和质量都非常低，尽管这些项目提供了一个很好的机会来实施以探究为基础的科学教育方法。该项目将与生物教师合作，提供培训、指导和开展科学博览会项目的机会，以激发人们对生物学的兴趣，激励科学事业，并在历史上STEM教育服务不足的地区提高科学素养。定义和研究压力一直是具有挑战性的，因为压力反应跨越多个生物尺度，而压力的后果往往是非线性的。缺乏整合是这一领域的主要障碍，糖皮质激素和热休克蛋白为重点的应激反应研究就是很好的例证。因此，这个项目将描述一种涉及热休克蛋白和糖皮质激素的综合应激反应。具体地说，这个项目将测试这一假设，即热休克蛋白和糖皮质激素相互启动对方的反应，为后续的应激源做准备，确定1)糖皮质激素是否上调HSP和相关的转录因子，以及2)受热休克反应途径调节的蛋白平衡的破坏，引发糖皮质激素反应。热休克蛋白和糖皮质激素的升高既有保护作用，也有损害作用。同素作用模型概念化了压力的这种非线性性质，但这一模型还没有得到明确的测试。利用斑马雀通过预先的热适应来调整它们的耐热性，该项目还将通过测试以下假设来评估异体平衡模型：经过预适应的鸟类比没有事先接触应激源的鸟类产生更大的HSP和糖皮质激素反应，从而保护个体免受与应激相关的生殖和免疫功能抑制。通过定义热休克蛋白和糖皮质激素反应之间的直接和相互关系，该项目将描述热休克蛋白反应的组织协调，并为糖皮质激素从保护作用向损害作用的转换提供分子基础。此外，该项目还将对异体平衡模型进行深入评估，以及该模型是否适用于营养压力以外的压力源。

Stressful events can permanently modify how an organism functions. Those same conditions in adults can also be traced back to events early in life. Therefore understanding how organisms respond to environmental stress is crucial. However, this has been challenging partly because although responses to stress have been studied at but the cellular and whole organism level, scientists have not yet made a successful link between stress to the whole animal and the cellular consequences. The goals of the project are to 1) improve our understanding of stress responses at both levels and 2) critically evaluate how the stress response is regulated. This project also aims to improve science literacy and inquiry-based science education in rural regions of Alabama. First, this project will contribute to a more holistic view of how organisms respond to stress, and will teach middle and high-school students how events at molecular and whole-animal levels are interconnected. Second, models describing stress response regulation have been applied to evaluate diseases risk factors, e.g., obesity and socioeconomic status. This project will educate Alabamian public school students about the consequences of obesity, lifestyle, and diet and how to overcome stress. Finally, the participation in, and quality of, science fair projects in southeastern Alabama has been extremely low, although such projects provide a great opportunity to implement an inquiry-based approach to science education. In collaboration with biology teachers, the project will provide training, mentorship, and opportunities to conduct science fair projects to spark interests in biology, inspire scientific careers, and increase science literacy in regions historically underserved in STEM education.Conceptualizing and studying stress has been challenging because stress responses extend across multiple biological scales, and the consequences of stress are often non-linear. This lack of integration is a major obstacle in this field, and is well exemplified by glucocorticoid- and heat shock protein-focused studies of stress responses. Therefore, this project will characterize an integrative stress response involving both HSPs and glucocorticoids. Specifically, this project will test the hypothesis that HSPs and glucocorticoids prime each other's response in preparation for subsequent stressors by determining whether 1) glucocorticoids elevate HSP and associated transcription factor and 2) a disruption in proteostasis, as regulated by the heat shock response pathway, elicits glucocorticoid responses. Elevation of HSPs and glucocorticoids has both protective and damaging effects. The allostasis model conceptualizes this non-linear nature of stress, yet this model has not been explicitly tested. Using zebra finches which adjust their heat tolerance with prior heat-conditioning, the project will also evaluate the allostasis model by testing the hypothesis that pre-conditioned birds elicit greater HSP and glucocorticoid responses than birds with no prior exposure to the stressor, thereby protecting individuals from stress-related suppression of reproductive and immune functions. By defining the direct and reciprocal relationship between HSP and glucocorticoid responses, this project will characterize organismal orchestration of the HSP response and provide a molecular basis for the switch from protective to damaging effects of glucocorticoids. Furthermore, this project will provide an in-depth evaluation of the allostasis model and whether this model applies to a stressor beyond nutritional stress.