A multi-component screen for feeding behaviour and nutritional status in Drosophila to interrogate mammalian appetite-related genes
A multi-component screen for feeding behaviour and nutritional status in Drosophila to interrogate mammalian appetite-related genes
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DOI：
10.1101/2020.05.04.076489
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发表时间：
2020-05
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影响因子：
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通讯作者：
J. Chalmers;Y. Tung;C. Liu;C. O'Kane;S. O’Rahilly;G. Yeo
中科院分区：
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作者：
J. Chalmers;Y. Tung;C. Liu;C. O'Kane;S. O’Rahilly;G. Yeo
超过300种基因变异与人类肥胖的测量密切相关。导致人类肥胖的高渗透性突变主要是通过破坏大脑中的饱腹感通路和增加食物摄入量来实现的。大多数常见的肥胖易感性变异都在大脑中高度表达的基因内或附近，但对它们的功能知之甚少。在哺乳动物系统中大规模探索这些基因的生物学是具有挑战性的。因此，我们试图利用易驯化的模式生物黑腹果蝇，建立并验证多组分筛选进食行为和营养状况的使用。我们验证了我们的筛选，证明了它能够区分破坏影响苍蝇能量平衡的四种基因的神经元表达的效果，以及十个控制基因。然后我们用我们的屏幕来询问两个基因数据集。首先，我们通过人类基因组全关联研究（GWASs）研究了53个与能量稳态有关的基因：在研究的53个果蝇同源基因中，我们发现16个显著影响摄食行为或营养状况。其次，我们研究了参与进食/禁食的下丘脑神经元特定群体（POMC和AgRP神经元）中表达和营养反应的基因：研究了47个小鼠基因的50个果蝇同源基因，我们的筛选发现了10个影响果蝇的摄食行为或营养状况。总之，果蝇为哺乳动物摄食行为和肥胖相关基因的高通量研究提供了一个有价值的模型系统。新的高通量技术已经发现了大量可能参与控制食物摄入和体重的候选基因，其中许多基因在大脑中高度表达。然而，我们如何从这些越来越长的基因列表中找到功能上最相关的基因呢？食欲需要在整个动物的背景下进行研究，但在人类和老鼠身上进行研究需要很长时间，而且成本高昂。果蝇虽然在进化上与哺乳动物有着明显的距离，但在生物学上却与哺乳动物有着惊人的相似之处，与人类遗传疾病有关的75%的基因在果蝇中是相同的。特别是，果蝇在食物摄入方面有着惊人的保守神经回路。在这里，我们开发了一套四种不同的功能分析来研究苍蝇的摄食行为和能量平衡。然后，我们使用这些试验来探索破坏果蝇神经元中基因表达的影响，这些基因要么通过人类基因研究与体重有关，要么在参与摄食的特定神经元群体中表达和营养反应。我们的研究表明，使用果蝇既省时又经济，是研究哺乳动物摄食行为和肥胖相关基因的一个有价值的模型系统。
More than 300 genetic variants have been robustly associated with measures of human adiposity. Highly penetrant mutations causing human obesity do so largely by disrupting satiety pathways in the brain and increasing food intake. Most of the common obesity-predisposing variants are in, or near, genes that are expressed highly in the brain, but little is known about their function. Exploring the biology of these genes at scale in mammalian systems is challenging. We therefore sought to establish and validate the use of a multicomponent screen for feeding behaviour and nutrient status taking advantage of the tractable model organism Drosophila melanogaster. We validated our screen by demonstrating its ability to distinguish the effect of disrupting neuronal expression of four genes known to influence energy balance in flies from ten control genes. We then used our screen to interrogate two genetic data sets. Firstly, we investigated 53 genes that have been implicated in energy homeostasis by human genome wide association studies (GWASs): of the 53 Drosophila orthologues studied, we found that 16 significantly influenced feeding behaviour or nutrient status. Secondly, we looked at genes which are expressed and nutritionally responsive in specific populations of hypothalamic neurons involved in feeding/fasting (POMC and AgRP neurons): 50 Drosophila orthologues of 47 murine genes were studied, and 10 found by our screen to influence feeding behaviour or nutrient status in flies. In conclusion, Drosophila provide a valuable model system for high throughput interrogation of genes implicated in feeding behaviour and obesity in mammals. Author Summary New high-throughput technologies have resulted in large numbers of candidate genes that are potentially involved in the control of food intake and body-weight, many of which are highly expressed in the brain. How, though, are we to find the functionally most relevant genes from these increasingly long lists? Appetite needs to be explored in context of a whole animal, but studies in humans and mice take a long time and are expensive. The fruit fly, while clearly evolutionarily distant, shares a surprising amount of biology with mammals, with 75% of genes involved in inherited human diseases having an equivalent in flies. In particular, the fruit fly has surprisingly conserved neuronal circuitry when it comes to food intake. Here we have developed a suite of four different functional assays for studying the feeding behaviour and energy balance in flies. We then used these assays to explore the effects of disrupting the expression of genes in the neurons of flies, that either are implicated in body weight through human genetic studies or are expressed and nutritionally responsive in specific populations of neurons involved in feeding. We show that the use of fruit flies are time and cost efficient, and are a valuable model system for studying genes implicated in feeding behaviour and obesity in mammals.