Mechanisms of mitochondrial-ER communication during dietary and thermal induced stress

项目总结/摘要 肥胖是一种影响40%人口的流行病，它增加了严重代谢疾病的风险 包括2型糖尿病和严重的SARS-CoV 2感染。肥胖会降低胰岛素敏感性， 葡萄糖稳态失调，维持高血糖水平，并发展为2型糖尿病。 激活棕色脂肪细胞（BAs）是治疗肥胖和相关疾病的有希望的方法。布朗 脂肪细胞依赖于广泛的线粒体网络，线粒体网络增加能量消耗并维持 通过葡萄糖、氨基酸和脂肪酸的氧化来维持葡萄糖的体内平衡。在脂肪引起的压力下， 内质网（ER）通讯维持BA的细胞功能。但 肥胖时，内质网-内质网通讯塑造细胞适应的机制很差， 明白因此，研究这些途径将为靶向肥胖提供新的治疗方法。 本申请的主要目标是研究细胞-ER通信的机制， 线粒体功能和细胞内稳态在饮食诱导的压力。我们在学士学位中已经描述过了 在冷刺激过程中，脑-内质网通讯通过内质网驻留的 激酶PERK。为了跟进这项工作，在目标1中，将研究长期高脂饮食（HFD）的影响， UCP 1-Cre PERK-/-小鼠暴露于不同的饮食和生物能量条件。我们的初步信息 表明PERK可能是信号分子伴侣PPID控制线粒体蛋白输入。在目标2中， 使用低温电子显微镜（CryoEM）的结构方法将用于探索分子 控制和维持BA中线粒体功能的相互作用，包括线粒体蛋白质输入， 重点研究了PPID依赖性途径和饮食和热应激过程中的细胞呼吸。最后，在Aim 3.研究PPID在饮食应激和热应激小鼠中的生理和细胞功能作用。 虽然目标1和目标2的一部分将在培训阶段完成，但目标2的一部分和整个目标3将在 这是在授标的独立阶段进行的。 本申请中提出的不同领域的广泛培训，包括生理学和细胞学， 结构生物学将提供工具，成为一个独立的研究人员和研究的机制， 调节线粒体生物发生和细胞代谢的细胞器通讯。将培训以文件形式进行 丹娜-法伯癌症研究所和哈佛医学院充满活力的科学界收到了。这 环境将使我接触到职业发展和未来所需的合作和讨论 机会Puigserver博士的指导将支持建立这些联系，并积极指导我 在演讲和手稿准备，学生指导，实验设计和职业发展。在一起， 在此申请中提出的研究和职业发展计划将加强我的技能， 竞争力，成为一个独立的研究人员在一个主要的机构。

Project Summary/Abstract Obesity is a pandemic affecting 40% of the population that increases the risk of serious metabolic diseases including type 2 diabetes and severe forms of SARS-CoV2 infection. Obesity reduces insulin sensitivity and dysregulates glucose homeostasis sustaining high blood glucose levels and the development of type 2 diabetes. Activation of brown adipocytes (BAs) is a promising approach to treat obesity and associated diseases. Brown adipocytes rely on an extensive network of mitochondria that increases energy expenditure and maintains glucose homeostasis through glucose, amino acid, and fatty acid oxidation. During fat-induced stress, mitochondrial-endoplasmic reticulum (ER) communication sustains cellular function in BAs. However, the mechanisms by which mitochondrial-ER communication shapes cellular adaptation during obesity are poorly understood. Therefore, studying these pathways will provide new therapeutical approaches to target obesity. The main goal of this application is to study the mechanisms of mitochondrial-ER communication that ensure mitochondrial function and cellular homeostasis during diet-induced stress. We have described that in BAs mitochondrial-ER communication promotes thermogenesis during cold stimulation through the ER-resident kinase PERK. To follow up this work, in Aim 1, the effects of long-term high fat diet (HFD) will be studied in UCP1-Cre PERK-/- mice exposed to different dietary and bioenergetic conditions. Our preliminary information suggests that PERK may be signaling to the chaperone PPID to control mitochondrial protein import. In Aim 2, structural approaches using Cryogenic Electron Microscopy (CryoEM) will be used to explore the molecular interactions that control and maintain mitochondrial functions in BAs including mitochondrial protein import, focusing on PPID-dependent pathway, and cellular respiration during dietary and thermal stress. Finally, in Aim 3 the role of PPID in physiology and cellular functions will be studied in mice exposed to diet and thermal stress. While Aims 1 and part of 2 will be completed during the training stage, part of Aim 2 and the entire Aim 3 will be conducted during the independent phase of the award. The extensive training in different fields proposed in this application including physiology and cellular and structural biology will provide the tools to become an independent researcher and study the mechanisms of inter- organalle communication that regulate mitochondrial biogenesis and cellular metabolism. This training will be received in the vibrant scientific communities of Dana-Farber Cancer Institute and Harvard Medical School. This environment will expose me to the collaborations and discussions necessary for career development and future opportunities. Dr. Puigserver mentorship will be supportive to establish those connections and actively guide me in talk and manuscript preparation, student mentorship, experimental design, and career development. Together, the research and career development plans proposed in this application will strengthen my skills and competitiveness to become an independent researcher at a major institution.