Role of miRNAs in the transmission of metabolic risks

儿童肥胖症的流行与环境因素密切相关。对人类进行的家族聚集研究和对动物模型进行的跨代研究表明，肥胖具有高度遗传性，祖先接触肥胖会使后代易患各种代谢紊乱。我们的实验室是第一个显示父亲运动在后代中编程“节俭表型”中的作用。我们发表的和初步的OXPHOS效率分析使用果蝇和小鼠模型表明，“节俭表型”是由后代的线粒体生物能量效率的改变引起的。 初步的蛋白质组学和转录组学分析表明，生物能量效率的发育变化是由于线粒体蛋白质组重塑与体细胞和生殖细胞microRNA（miRNA）的改变，从而提供了一个潜在的机制，跨代传递和编程的代谢风险。该项目的中心假设是，miRNAs在线粒体生物能量效率的发育编程中发挥关键作用。基于已发表的和初步的数据，第二个假设是线粒体生物能量效率的变化通过精子细胞作为miRNA的改变而遗传。为了验证这些假设，我们建议利用果蝇的生理简单性和遗传操纵性。因此，该项目的具体目标是： 目标1.确定改变的miRNA表达在编程后代代谢状态中的功能后果。 目标二。确定负责生物能表型跨代编程的精子表位突变。 该项目的方法创新包括应用多路检测平台和最近在苍蝇中采用的可变能量钳技术，这是一种基于蛋白质组学的新型方法，将线粒体通量数据与内部蛋白质组学合并，以揭示跨代表型的分子标记。这项研究有望大大推进我们对儿童肥胖表观遗传起源的理解。破译发育代谢编程的主要分子机制将更好地了解如何更有效地针对儿童肥胖和相关代谢疾病。

The childhood obesity epidemic has been strongly associated with environmental factors. Family aggregation studies in humans and transgenerational studies in animal models show that obesity is highly heritable, and ancestral exposures can predispose offspring to the risk of various metabolic disorders. Our laboratory was the first to show the role of paternal exercise in programming “thrifty phenotype” in offspring. Our published and preliminary OXPHOS efficiency analyses using Drosophila and mouse models indicate that the “thrifty phenotype” is caused by an alteration in the offspring's mitochondrial bioenergetic efficiency. Preliminary proteomic and transcriptomic analyses revealed that developmental changes in bioenergetic efficiency were due to mitochondrial proteome remodeling associated with alterations in somatic and germ cell microRNAs (miRNAs), thereby providing a potential mechanism for the transgenerational transmission and programming of metabolic risks. The central hypothesis of the project is that miRNAs play a key role in the developmental programming of mitochondrial bioenergetic efficiency. Based on published and preliminary data, a secondary hypothesis is that changes in mitochondrial bioenergetic efficiency are inherited via spermatozoal cells as alterations in miRNAs. To test these hypotheses, we propose to take advantage of the physiological simplicity and genetic manipulability of fruit fly Drosophila. Therefore, the specific aims for this project are: Aim 1. Determine the functional consequences of altered miRNA expression in programming offspring metabolic state. Aim 2. Determine the spermatozoal epimutations responsible for the transgenerational programming of the bioenergetic phenotype. The methodological innovations of this project include the application of a multiplexed assay platform with a variable energetic clamp technique recently adopted to flies, a novel proteomics-based approach to merge mitochondrial flux data with in-house proteomics to reveal molecular markers of transgenerational phenotype. This study is expected to significantly advance our understanding of the epigenetic origins of childhood obesity. Deciphering primary molecular mechanisms of developmental metabolic programming will provide a better understanding of how childhood obesity and related metabolic diseases could be more effectively targeted.