Modeling anorexia nervosa with human pluripotent stem cells

描述(由申请人提供)：该项目的主要目标是确定神经性厌食症(AN)的疾病神经元的定义特征，在解决导致遗传变异的风险、多巴胺受体过量、感觉不到奖励和AN极端的食物限制表型之间的相互作用的过程中。神经性厌食症是一种高度遗传性的疾病，在精神疾病中死亡率最高，但缺乏有效的治疗方法。死亡时高度营养不良的状态阻碍了对脑组织机制线索的研究。将体细胞的基因重新编程为多能状态可产生诱导多能干细胞(IPSCs)，并已使用人类细胞完成。由此产生的IPSCs与供体个体是同源的，即它们具有相似的遗传背景，并可以分化为功能神经元。因此，IPSCs对于理解复杂的神经精神疾病非常有吸引力，例如AN，在这些疾病中，访问和分析神经组织是一个巨大的限速步骤。利用人类IPSCs作为生物学工具来了解无法治疗的大脑疾病，如AN，其特殊价值不仅来自于对大脑病理生理学的洞察，而且还因为有可能加快发现可以改变这种青春期疾病进展的疗法。不足为奇的是，ipscs的非凡潜力引发了研究人员对各种神经精神障碍患者的浓厚兴趣和兴奋，因为它们可能揭示干预的途径。这项合作提案中对AN的研究提供了一个理想的环境，因为我们将通过国际AN治疗研究，利用当地收集的患有AN的青少年及其家人的队列，我们小组正在评估他们的临床病程、治疗结果、基因测序(普莱斯基金会赠款)和奖励途径的神经成像。因此，这一建议最大限度地发挥了创新技术组合的潜在科学影响，同时显著增强了其可行性。此外，ANN的极端临床表型，结合有关风险相关基因和感觉奖赏缺陷的新兴数据，为拟议的研究提供了一个令人信服的案例。为此，具体目标是：(1)从患有糖尿病的患者和健康对照的个体中提取IPSCs；(2)分析来自对照和IPSCs的神经细胞的基因表达谱；以及(3)检验跨水平假说，例如，通过神经成像看到的导致多巴胺受体过量的神经机制，并确定导致风险的遗传机制在这一过程中的作用。根据我们的假设，多能干细胞将被驱动分化为多巴胺能神经元，用于未来的机制探索。阐明基因、奖励机制和极端进食行为之间的联系，无疑有可能不仅产生神经性厌食症的机制和治疗知识，而且还可能产生新出现的肥胖流行病的知识。 公共卫生相关性：神经性厌食症(AN)是一种高度遗传性疾病，在精神疾病中死亡率最高，但缺乏有效的治疗方法。将体细胞的基因重新编程为多能状态可产生诱导多能干细胞(IPSC)，这些干细胞与供体个体具有相同的基因，即它们具有相似的遗传背景。我们将比较来自对照组和IPSC的神经细胞的基因表达谱，并测试导致风险的遗传变异对神经元表型的贡献。

DESCRIPTION (provided by applicant): The overarching goal of this project is to identify the defining characteristics of disease neurons in Anorexia Nervosa (AN), in the course of addressing the interplay between risk conferring genetic variations, excess of dopamine receptors, inability to sense reward and the extreme food restricting phenotype of AN. Anorexia nervosa is a highly heritable disorder with the highest mortality among psychiatric illnesses, yet lacking effective treatments. Highly malnourished status at death has obstructed the study of brain tissue for mechanistic clues. Genetic reprogramming of somatic cells to a pluripotent state produces induced pluripotent stem cells (iPSCs), and has been accomplished using human cells. The resulting iPSCs are isogenic to the donor individual, i.e., they carry a similar genetic background, and can be differentiated into functional neurons. Thus, iPSCs are extremely attractive for understanding complex neuropsychiatric diseases such as AN, where accessing and analyzing neural tissue is a tremendous rate-limiting step. The special value of using human iPSCs as a biological tool to understand untreatable brain disorders such as AN, comes not only from the promise of insights into brain pathophysiology, but also for the potential to accelerate the discovery of therapeutics that can modify progression of this adolescent-onset illness. Not surprisingly, the remarkable potential of iPSCs has sparked profuse interest and excitement in researchers studying individuals with a variety of neuropsychiatric disorders, because of their potential to reveal avenues for intervention. The study of AN in this collaborative proposal provides an ideal setting as we will leverage a locally collected cohort of adolescents with AN and their families via the International AN Treatment Study, who are being assessed by our group for clinical course, treatment outcome, genetic sequencing (Price Foundation grant) and neuroimaging of the reward pathway. Thus, this proposal maximizes the potential scientific impact of a combination of innovative technologies while remarkably enhancing their feasibility. Furthermore, the extreme clinical phenotype of AN combined with emerging data on risk conferring genes and deficits in sensing reward make a compelling case for the proposed study. To this end, the Specific Aims are: (1) to derive iPSCs from individuals with AN as well as healthy controls; (2) to analyze the gene expression profile of neural cells derived from controls and AN iPSCs; and (3) to test cross-level hypotheses, e.g., the neural mechanisms that result in the excess of dopamine receptors seen via neuroimaging and to determine the contribution of risk conferring genetic mechanisms to this process. The pluripotent stem cells will be driven to differentiate into dopaminergic neurons for future mechanistic explorations based on our hypotheses. Elucidating the links between genes, reward mechanisms and extremes of eating behaviors have the unmistakable potential of yielding mechanistic and therapeutic knowledge of not only anorexia nervosa but also of the emerging epidemic of obesity. PUBLIC HEALTH RELEVANCE: Anorexia nervosa (AN) is a highly heritable disorder with the highest mortality among psychiatric illnesses, yet lacking effective treatments. Genetic reprogramming of somatic cells to a pluripotent state produces induced pluripotent stem cells (iPSC), and that are isogenic to the donor individual, i.e., they carry a similar genetic background. We will compare the gene expression profile of neural cells derived from controls and AN iPSC and test the contribution of risk-conferring genetic variants to the neuronal phenotype.