Developing a Drosophila melanogaster model of the cardiac myocyte action potential to investigate function and performance

即使像人类和苍蝇那样相隔数百万年的进化，动物细胞、组织和器官执行其基本功能的分子机制也常常具有惊人的相似性。苍蝇和人类的心脏当然也是如此，尽管它们在大小和形状上有很大的不同，但在控制心脏发育的基因和细胞内发现的分子成分方面却有着惊人的相似之处。有了如此强烈的相似性，对果蝇心脏的研究有可能成为脊椎动物心脏的重要信息来源，这对预防心脏病非常重要，而心脏病是人类死亡的主要原因。对果蝇（Drosophila melanogaster）的研究表明，这两者在分子和发育方面存在显著的相似性。心脏发育的关键基因在昆虫和哺乳动物之间是同源的，它们是心肌细胞生理学的关键组成部分，包括离子通道、泵和交换器。然而，令人惊讶的是，尽管在了解心脏细胞的基本生物学方面可以应用于脊椎动物，并且可以减少/取代对脊椎动物实验的需求，但果蝇成年心脏的详细生理学研究却很少被探索。对果蝇心脏的研究几乎完全集中在通过心电图（ECG）测量的幼虫心脏的输出上，而忽略了细胞水平。然而，心脏细胞能够表现出大量的可塑性和冗余性，因此了解总体输出不足以表征作为药物目标的分子网络变化的影响。因此，为了实现果蝇心脏基因筛选和药物发现的潜力，从分子和细胞到器官/系统的所有水平的特征都是必不可少的。这个学生的目标是通过开发技术来纠正这一缺陷，允许记录成年活果蝇的心脏细胞活动。这些技术将为果蝇心脏细胞提供前所未有的信息，这些信息可以整合到心脏细胞如何单独和共同运作的计算机模型中。实验和计算机模型的结合对于确定药物或突变的影响至关重要。该学生的目的是通过应用现有技术（如细胞内清晰记录，计算建模）以及新技术（如全细胞贴片）的开发来表征和产生心肌细胞动作电位的模型。有了这样一个基于详细电特征的模型，就有可能利用大规模的基因筛选，对心脏功能和替代脊椎动物的候选药物可能产生的影响做出关键的见解。这些见解可用于为随后的脊椎动物研究提供信息，从而减少此类研究中使用的动物数量。这种方法将产生一种系统，可用于研究心脏细胞的基本分子生物学，也可用于筛选药物，以寻找其改变心脏细胞活性的潜在价值。这将是无价的，减少了需要用于基础研究和药物发现早期阶段的脊椎动物的数量，同时也降低了研究成本。

Even when separated by millions of years of evolution, as are humans and flies, the molecular mechanisms through whichanimal cells, tissues and organs perform their basic functions often possess remarkable similarities. This is certainly truefor the hearts of flies and humans, which despite being rather different in size and shape, share remarkable similarities interms of the genes controlling its development and the molecular components found within the cells. With such strongsimilarities, the study of the heart of flies has potential as an important source of information about the vertebrate heart thatis so important for preventing heart disease, which is a major source of human mortality.Studies in the fruit fly, Drosophila melanogaster, have demonstrated remarkable molecular and developmental similaritiesbetween the two. Key genes in heart development are homologous between insects and mammals (e.g. tinman), as arekey components of cardiac myocyte physiology, including ion channels, pumps and exchangers. Surprisingly, however, thedetailed physiology of the fruit fly adult heart has been little explored, despite potential boons in terms of understanding thebasic biology of heart cells that can be applied to vertebrates, and for reducing/replacing the need for experimentation onvertebrates.Investigations of the Drosophila heart have focussed almost exclusively on the output of the larval heart measured throughthe electrocardiogram (ECG), ignoring the cellular level. Yet, heart cells are capable of showing substantial plasticity andredundancy so knowing the overall output is insufficient to characterise the impact of changes in molecular networks thatare the targets of drugs. Thus, to realise the potential of the Drosophila heart for genetic screens and drug discovery it isessential to characterise all levels from molecular and cellular to organ/system.This studentship aims to rectify this deficiency by developing techniques to permit recording the activity of heart cells in liveadult fruit flies. These techniques will provide an unprecedented level of information on the fruit fly heart cells that can beincorporated into a computer model of how the heart cells function individually and together. The combination ofexperiment and computer model will be essential in identifying the effects of drugs or mutations.The aim of the studentship is to characterise and produce a model of the cardiac myocyte action potential through applyingexisting techniques (e.g. sharp intracellular recordings, computational modelling) as well as the development of newtechniques (e.g. whole-cell patch). With such a model based on a detailed electrical characterisation it would be possible touse large-scale genetic screens to make crucial insights into heart function and the possible impact of candidate drugsreplacing the need for vertebrates. These insights can be used to inform subsequent vertebrate research leading to areduction in the number of animals used in such studies.Such an approach is will produce a system that can be used to study the basic molecular biology of heart cells but also forscreening drugs for their potential value in altering heart cell activity. This will be invaluable, reducing the numbers ofvertebrates that need to be used in basic research and the early stages of drug discovery but also reducing research costs.