A novel Drosophila platform to replace the use of mice and zebrafish for the study of ER-mitochondria interactions.

人口迅速老龄化和与年龄有关的疾病负担是发达国家和发展中国家面临的两大社会和财政挑战。了解支撑衰老的分子过程是一个基本的生物学问题，也是设计可以延长健康预期寿命的干预措施的关键一步。了解导致神经元衰老的过程尤为重要，因为衰老是许多神经退行性疾病的主要危险因素。拟议的项目将通过揭示内质网和线粒体之间的通信随时间影响神经元功能的分子机制，促进我们对神经元衰老的细胞生物学的基本理解。两个细胞器之间的交流调节了许多过程，例如钙和磷脂的交换，这对正常的细胞功能至关重要。该项目将利用我们开发的一个新平台来监测黑胃果蝇er -线粒体的相互作用，这是一个长期项目的一部分，旨在研究神经元衰老的细胞生物学。研究成年动物神经元的细胞生物学需要活体或离体成像方法，这在脊椎动物模式生物中具有技术挑战性和耗时。此外，这类研究需要大量的动物，并且经常使用外科手术。我们的成像系统提供了非侵入性的，详细的成像细胞内动态过程在老化的果蝇神经元。该系统利用了对果蝇成年翅膀感觉神经元的显微观察。果蝇的寿命相对较短，这使得纵向研究成为可能，而在这种生物体中可用的复杂遗传工具极大地促进了功能研究。我们的方法代表了该领域的重大进步，允许完整成人神经系统中活神经元的成像与强大的遗传工具相结合。有了这个系统，我们已经能够在理解特定神经元功能在衰老过程中如何衰退方面取得重大进展。在我们过去的工作中，我们已经发现果蝇成年神经元线粒体轴突运输的显著年龄依赖性下降。在衰老过程中，转运减少会导致更广泛的神经元稳态下降，而这一过程的上调似乎对老年神经元有益。尽管这些发现提供了线粒体运动和神经元功能之间的强烈关联，但仍不清楚运输调节如何在机制上影响神经元衰老表型。一个令人兴奋的可能性是，线粒体和内质网之间的相互作用将直接调节线粒体的运输和功能，从而显著影响神经元的衰老。通过将我们的技术转移到意大利帕多瓦大学Tito Cali博士的实验室，这项工作将减少用于研究er -线粒体通信的小鼠和斑马鱼的数量，并进一步扩大我们的果蝇模型的效用，以最大限度地发挥其3Rs潜力。

A rapidly ageing population and the associated burden of age-related disease are two of the major societal and financial challenges facing developed and developing countries. Understanding the molecular processes that underpin ageing is a fundamental biological question and a critical step in designing interventions that could increase healthy life expectancy (healthspan). It is particularly important to understand the processes that contribute to ageing of neurons, as ageing is a major risk factor for many neurodegenerative diseases.The proposed project will advance our basic understanding of the cell biology of neuronal ageing by shedding light on the molecular mechanisms by which the communication between the ER and the mitochondria affects neuronal functionality over time. Communication between the two organelles regulates a number of processes, for instance calcium and phospholipids exchange, essential for proper cellular functions. The project will take advantage of a new platform that we developed to monitor ER-mitochondria interactions in Drosophila melanogaster as part of a long-term project aimed at studying the cell biology of neuronal ageing. Studying the cell biology of neurons in adult animals requires intravital or ex vivo imaging approaches, which in vertebrate model organisms are technically challenging and time-consuming. Moreover, such studies require a significant number of animals and often use surgical procedures. Our imaging system affords non-invasive, detailed imaging of intracellular dynamic processes in ageing neurons of ageing fruit flies. This system exploits the accessibility to microscopic observation of sensory neurons in the adult wing of Drosophila. The relatively short lifespan of fruit flies makes longitudinal studies feasible and the sophisticated genetic tools available in this organism greatly facilitate functional studies. Our methodology represents a significant advance for the field, allowing imaging of live neurons in an intact adult nervous system to be coupled to powerful genetic tools. With this system, we have been able to make significant progress towards understanding how specific neuronal functions decline during ageing. In our past work, we have discovered a remarkable age-dependent decline in the axonal transport of mitochondria in adult neurons of Drosophila. Reduced transport contributes to the broader decline of neuronal homeostasis that occurs during ageing while upregulation of this process appears to be beneficial in older neurons. Although these findings provide a strong association between mitochondrial motility and neuronal function, it is still unknown how modulation of transport mechanistically affects neuronal ageing phenotypes. An exciting possibility is that the interactions between the mitochondria and the ER would directly regulate mitochondrial transport and functions thus significantly impacting on neuronal ageing. By transferring our technology into the laboratory of Dr Tito Cali at the University of Padova (Italy), this work will reduce the number of mice and zebrafish used to study ER-mitochondria communications and further expand the utility of our Drosophila model to maximise its 3Rs potential.