IPSC phenotype, mitochondrial haplotype and psychosis in 22q11 deletion syndrome

代谢受损，包括线粒体功能障碍，可能会导致 精神分裂症。然而，探索线粒体功能障碍与神经的关系的方法 功能障碍和精神分裂症的风险是必要的。精神分裂症最常见的遗传危险因素是 22q11.2缺失综合征(22q11DS)，发生这种疾病的风险为25%。有趣的是，在 22q11DS大约40个缺失基因中有6个编码线粒体定位蛋白。我们已经集合好了 一个多学科团队结合使用22q11DS患者的干细胞来源的神经元，无论是否有 对22q11DS伴和不伴精神分裂症的患者进行了基因分析。我们 将检验这一假设，即在22q11DS背景下线粒体相关基因内的“二次命中”增加 神经元的代谢功能障碍，并与患者患精神分裂症的风险增加有关。 目的1.研究22q11DS来源的前脑神经元的线粒体功能。 将比较来自3组的现有IPSC系：1)22q11DS伴精神分裂症，2)22qDS不伴精神分裂症 精神分裂症或精神病病史(25岁以上)，以及健康对照。前脑样神经元 将从这些线条中比较线粒体功能障碍的证据，这在 22q11DS+SZ组。与22q11缺失的基因之一是MRPL40的事实一致，MRPL40是 线粒体核糖体，我们的初步证据表明，来自22q11DS+SZ的IPSC神经元 研究小组减少了COX1的翻译，这是一种关键的线粒体DNA编码蛋白。他们也有 细胞色素C氧化酶活性显著降低，并有强烈的氧化损伤迹象。 目的2.在22q11DS中，线粒体功能的遗传“二次点击”是否与精神病有关？ 我们将使用大约600名22q11DS患者的全基因组序列数据，这些患者平均分为 没有慢性精神病，来自国际22q11.2DS大脑和行为联盟(22QIBBC)。 生物信息学处理将确定22q11DS中发生SZ的风险是否受到潜在影响 由线粒体单倍群引起，或与mtDNA突变增加有关，或与IS有关 与产生线粒体的核编码基因突变的增加有关- 起作用的蛋白质。未来的研究将使用线粒体胞质(‘交换’)技术，基因组 编辑、“回放”实验和其他方法来测试从目标2开始的结果的功能相关性 线粒体在22q11DS来源的IPSCs中的功能，并可能从其他高危SZ延伸到IPSCs 组。这些结果也可以用来检查22q11ds儿童发生发展的潜在风险。 慢性精神病，使用22QIBBC目前正在登记和研究的大量受试者。 意义这项研究的结果可能导致改善预测、治疗和预防 22q11DS的精神病，并可推广到22q11DS以后的精神病的治疗或预防。

Metabolic compromise, including mitochondrial dysfunction, may contribute to the development of symptoms in schizophrenia. However, approaches to explore the relationship between mitochondrial dysfunction, neural dysfunction, and schizophrenia risk are needed. The most common genetic risk factor for schizophrenia is the 22q11.2 deletion syndrome (22q11DS), associated with a 25% risk of developing this disorder. Interestingly, in 22q11DS six of the roughly 40 deleted genes encode for mitochondrial-localizing proteins. We have assembled a multidisciplinary team to combine the use of stem cell derived neurons from 22q11DS patients with or without schizophrenia, and controls, with genetic analyses of 22q11DS patients with and without schizophrenia. We will test the hypothesis that a “second hit” within mitochondrial-related genes in the 22q11DS context increases metabolic dysfunction in neurons and is associated with an increased risk for schizophrenia in patients. Aim 1. Investigation of mitochondrial function in 22q11DS derived forebrain neurons. Existing IPSC lines from 3 groups will be compared: 1) 22q11DS with schizophrenia, 2) 22qDS without schizophrenia or history of psychosis (and over the age of 25), and healthy controls. Forebrain-like neurons from these lines will be compared for evidence of mitochondrial dysfunction that is most pronounced in the 22q11DS+SZ group. Consistent with the fact that one of the 22q11-deleted genes is MRPL40, a subunit of the mitochondrial ribosome, our preliminary evidence suggests that IPSC-derived neurons from the 22q11DS+SZ group have reduced translation of COX1, a key mitochondrial DNA-encoded protein. They also have significantly reduced cytochrome C oxidase activity, and strong evidence of oxidative damage. Aim 2. Are genetic “second hits” to mitochondrial function associated with psychosis in 22q11DS? We will use whole genome sequence data from about 600 22q11DS patients, evenly split between those with and without chronic psychosis, from the International 22q11.2DS Brain and Behavior Consortium (22QIBBC). Bioinformatic processing will determine whether the risk of developing SZ in 22q11DS is potentially influenced by the mitochondrial haplogroup, or is associated with an increased presence of mutations in mtDNA, or is associated with an increased presence of mutations in nuclear-encoded genes that generate mitochondrial- functioning proteins. Future studies would employ mitochondrial cybrids (`swapping”) technology, genome editing, “putback” experiments, and other approaches to test the functional relevance of findings from Aim 2 on mitochondrial function in 22q11DS-derived IPSCs, and could be extended to IPSCs from other high-risk SZ groups. These results could also be used to examine the prospective risk of 22q11DS children to develop chronic psychosis, using the large cohort of subjects currently being enrolled and studied by the 22QIBBC. Significance The results of this study could lead to improved prediction, treatment, and prevention of psychosis in 22q11DS, and could generalize to the treatment or prevention of psychosis beyond 22q11DS.