Determining the effects of genetic variation and early life stress on the regulation of the galanin gene in fat and alcohol selection.

过度沉迷于高热量营养素，包括脂肪和酒精，对英国人口的健康产生了重大影响，67%的男性和57%的女性被归类为超重。由于肥胖与2型糖尿病和心血管疾病有关，我们需要找到这种卡路里过度消耗的原因，英国人口消耗的卡路里的主要来源是脂肪和酒精。除了心血管疾病和癌症，过度饮酒也与肝硬化和胰腺炎有关。由于DNA的差异，我们中的许多人都容易过度摄入脂肪和酒精，但也有证据表明，环境因素，如早期生活压力也起着作用。然而，我们仍然对影响我们摄入脂肪和酒精的机制以及这些机制如何受到遗传变异和环境的影响知之甚少。重要的线索出现了。例如，一种叫做甘丙肽的小神经肽在大脑中控制脂肪和酒精摄入的下丘脑区域表达。去除编码甘丙肽的基因可以减少脂肪和酒精的摄入，并减少体重增加。甘丙肽功能的一个关键方面是它应该在正确的细胞中以正确的量表达并响应正确的刺激。然而，人们对控制下丘脑甘丙肽产生的机制一无所知，也不知道控制这种表达的DNA区域的差异如何影响脂肪和酒精的摄入。我们首先发现了一个DNA开关序列，它是未发现的控制下丘脑甘丙肽的开关序列的绝佳候选者。然后我们发现，存在于人类群体中的这种开关的序列变化，与酗酒有关，增加了下丘脑中这种开关的强度。我们还发现了开关内的表观遗传变化，称为DNA甲基化，这些变化会因压力而改变，似乎也会改变开关的强度。我们假设GAL基因开关内的这些序列变化和甲基化变化共同作用，改变下丘脑中甘丙肽的产生，并影响脂肪和酒精的摄入。为了解决这一假设，我们使用了一种名为CRISPr基因组编辑的显着新方法，以快速有效地删除基因组中的开关。我们将初步确定去除开关对下丘脑甘丙肽产生的影响，并确定其对脂肪和酒精选择的影响。我们将再次使用CRISPr技术来重现开关内已知的人类序列变化（一种称为人源化的过程），以模拟它们对甘丙肽产生以及脂肪和酒精摄入的影响。然后，我们将使用这些“人源化”模型来确定早期生活压力对开关序列甲基化的影响，以及这种甲基化如何影响其功能。利用这项革命性的CRISPr技术，我们将确定人类群体中自然发生的变化，作为遗传或环境的结果，如何影响我们的脂肪和酒精摄入量。考虑到我们社会中肥胖和过量饮酒的巨大问题，这些研究不仅为理解遗传和环境在过量脂肪和酒精摄入中的作用开辟了道路，而且还为通过控制人类过量卡路里摄入来降低肥胖易感性提供了新的机会。

Overindulgence in high calorie nutrients, which include fat and alcohol, has had a major effect on the health of the UK population where 67% of males and 57% of females are classed as overweight. Because obesity is linked to type 2 diabetes and cardiovascular disease we need to find the causes of this calorie overconsumption and a major source of the calories consumed by the UK population come in the form of fat and alcohol. In addition to cardiovascular disease and cancer, excessive alcohol consumption is also linked to liver cirrhosis and pancreatitis. Many of us are susceptible to over consume fat and alcohol as a result of differences in our DNA but there is also evidence that environmental factors such as early life stress also play a role. However, we still know very little about the mechanisms that influence our intake of fat and alcohol and how these mechanisms are affected by genetic variation and environment. Important clues have emerged. For example, a small neuropeptide, called galanin is expressed in a region of the brain called the hypothalamus that controls fat and alcohol intake. Removal of the gene which encodes galanin reduces fat and alcohol intake and decreases weight gain. A critical aspect of the function of galanin is that it should be expressed in the correct cells, in the correct amount and in response to the correct stimuli. However, nothing was known about the mechanisms controlling the production of galanin in the hypothalamus or how differences in the regions of DNA that control this expression might affect fat and alcohol intake. We first discovered a DNA switch sequence that was an excellent candidate for the undiscovered switch sequence that controls galanin in the hypothalamus. We then found that sequence changes within this switch that exist within the human population, and were linked to alcohol abuse, increased the strength of this switch in the hypothalamus. We also found epigenetic changes within the switch, called DNA methylation, that were altered by stress and seemed to also change the strength of the switch. We hypothesise that these sequence changes and methylation changes within the GAL gene switch work together to alter the production of galanin in the hypothalamus and to influence fat and alcohol intake. To address this hypothesis we used a remarkable new method called CRISPr genome editing to quickly and efficiently delete the switch from the genome. We will initially determine the effects of removing the switch on galanin production in the hypothalamus and determine its effects on fat and alcohol selection. We will use CRISPr technology again to reproduce known human sequence changes within the switch (a process known as humanisation) to model their effects on galanin production and fat and alcohol intake. We will then use these "humanised" models to determine the effects of early life stress on the methylation of the switch sequence and how this methylation affects its function. Using this revolutionary CRISPr technology we will determine how changes that occur naturally in the human population, as a result of genetics or environment, affect our fat and alcohol intake. Considering the huge problem of obesity and excessive alcohol intake in our society these studies will open avenues for not only understanding the role of genetics and environment in excess fat and alcohol intake but will also provide novel opportunities for reducing susceptibility to obesity by controlling excess calorie intake in the human population.