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的相关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。了解衰老的分子过程是一个基本的生物学问题，也是设计可增加健康预期寿命的干预措施的关键一步。由于衰老是许多神经退行性疾病的主要危险因素，因此了解导致神经元衰老的过程尤为重要。拟议的项目将通过阐明ER和线粒体之间的通信随时间推移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。两个细胞器之间的通信调节许多过程，例如钙和磷脂交换，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果蝇中ER-线粒体的相互作用，作为旨在研究神经元衰老的细胞生物学的长期项目的一部分。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，这在脊椎动物模型生物中是技术上具有挑战性和耗时的。此外，这些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，详细的成像细胞内的动态过程中老化的果蝇神经元。该系统利用了对果蝇成虫翅中感觉神经元的显微观察。果蝇相对较短的寿命使得纵向研究成为可能，并且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展，允许在完整的成人神经系统中对活神经元进行成像，并将其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下降方面取得重大进展。在我们过去的工作中，我们已经发现了一个显着的年龄依赖性下降，在成年果蝇神经元的线粒体轴突运输。减少运输有助于在老化过程中发生的神经元稳态的更广泛的下降，而这一过程的上调似乎是有益的，在老年神经元。虽然这些发现提供了线粒体运动和神经元功能之间的强关联，它仍然是未知的运输机制的调制如何影响神经元老化表型。一个令人兴奋的可能性是，线粒体和ER之间的相互作用将直接调节线粒体的运输和功能，从而显着影响神经元的衰老。通过将我们的技术转移到帕多瓦大学（意大利）的蒂托博士卡利的实验室，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.