Epigenomic dysfunction at 16q24.1 vascular defects and perinatal consequences

16q24.1的表观基因组功能障碍--血管缺陷和围产儿后果。 摘要 FOXF1杂合性基因组缺失和点突变导致肺泡毛细血管发育不良 肺静脉错位(ACDMPV)，一种新生儿致死性发育性肺部疾病。浩瀚无边 大多数ACDMPV患者还有额外的心脏、胃肠道或泌尿生殖系统缺陷。 系统。间充质FOXF1转录因子在血管内皮细胞和平滑肌细胞中的表达 作为Sonic Hedgehog的下游靶标，在上皮-间充质信号转导中起重要作用 路径。我们积累了世界上最大的ACDMPV样本收集(N~145个家系)。最近， 我们发现在FOXF1和FOXF1上游~270 kb的蛋白质编码基因沙漠中存在基因组缺失 保持完整，表现出完整的ACDMPV表型。这些删除使我们能够定义~60 kb 组织特异性增强子区域，含有长的非编码RNA(LncRNAs)，LINC01081和LINC01082， 在胎儿肺中表达。另一个定位于FOXF1上游1.7kb的lncRNA，Fendrr 定向和可能利用与FOXF1相同的双向启动子，与染色质修饰相互作用 络合物(PRC)2调节基因表达。有趣的是，Fendrr的纯合缺失，使Foxf1完好无损， 导致新生小鼠的肺和心脏出现致命性缺陷。重要的是，我们发现FOXF1基因是 印记，可能使用这些lncRNA；31/32的特征性基因组缺失引起从头开始在母体 染色体16q24.1。在人类中，由母体减数分裂i不分离引起的16三体是最多的 常见的产前三体(占所有妊娠的1%)，除非早期胚胎抢救，否则是致命的。1/3 在这些病例中，患有母体UPD的儿童(16例)表现为IUGR(归因于三体胎盘)和多个 先天性畸形，包括心脏缺陷、肺发育不良、气管食管瘘、肠道 旋转不良、缺胆、肾发育不全、肾积水、肛门闭锁和单脐动脉。 有趣的是，除胎儿宫内发育迟缓外，上述所有临床特征均见于绝大多数患有胎儿宫内发育迟缓的儿童 ACDMPV。相比之下，父系UPD患者的表型相对正常(16例)， 16号染色体上的印记基因(S)可能是导致母体UPD(16)表型的原因。我们 假设FOXF1增强子和lncRNAs在16q24.1的基因组印记中起重要作用 可能对产妇UPD的主要特征负责(16)。在目标1中，我们将研究基因组的作用 FOXF1基因座在ACDMPV和UPD中的印记(16)。在目标2中，我们将分析FOXF1的功能 增强子，包括重叠的lncRNA。在目标3中，我们将研究Fendrr在 心脏、肺和胎盘的发育和疾病。拟议的研究将提供更好的 远距离组织特异性增强子在基因组印迹中的作用及其研究进展 和疾病。这一建议还将阐明lncRNAs在增强基因功能和基因调控中的作用。 通常，并提供关于这类有希望的治疗靶点的知识。

Epigenomic dysfunction at 16q24.1 – vascular defects and perinatal consequences. ABSTRACT Heterozygous genomic deletions and point mutations in the FOXF1 cause Alveolar Capillary Dysplasia with Misalignment of Pulmonary Veins (ACDMPV), a neonatally lethal developmental lung disease. The vast majority of ACDMPV patients have additional defects involving heart, gastrointestinal, or genitourinary systems. The mesenchymal FOXF1 transcription factor expressed in the endothelial and smooth muscle cells plays an important role in epithelium-mesenchyme signaling, as a downstream target of Sonic hedgehog pathway. We accumulated the largest collection of ACDMPV samples in the world (N~145 families). Recently, we found that genomic deletions mapping in a protein-coding gene desert ~270 kb upstream to FOXF1 and leaving it intact manifest with the full ACDMPV phenotype. These deletions enabled us to define an ~60 kb tissue-specific enhancer region harboring long non-coding RNAs (lncRNAs), LINC01081 and LINC01082, that are expressed in fetal lungs. Another lncRNA, FENDRR that maps 1.7 kb upstream of FOXF1 in the opposite orientation and likely utilizes the same bi-directional promoter as FOXF1, interacts with chromatin-modifying complex (PRC) 2 to regulate gene expression. Interestingly, homozygous loss of Fendrr, leaving Foxf1 intact, leads to lethal defects of lungs and heart in mouse neonates. Importantly, we found that the FOXF1 locus is imprinted, likely using these lncRNAs; 31/32 of the characterized genomic deletions arose de novo on maternal chromosome 16q24.1. Trisomy 16 in humans, resulting from maternal meiosis I nondisjunction, is the most common prenatal trisomy (>1% of all pregnancies) and lethal unless rescued early embryonically. In one-third of such cases, children with maternal UPD(16) manifest IUGR (attributed to trisomic placenta) and multiple congenital malformations, including heart defects, pulmonary hypoplasia, tracheosophageal fistula, gut malrotation, absent gall bladder, renal agenesis, hydronephrosis, imperforate anus, and single umbilical artery. Interestingly, all the above clinical features, except IUGR, are observed in the vast majority of children with ACDMPV. In contrast, relatively normal phenotype was reported in few patients with paternal UPD(16), and imprinted gene(s) on chromosome 16 were suggested as causative for maternal UPD(16) phenotype. We hypothesize that FOXF1 enhancer and lncRNAs play an important role in genomic imprinting at 16q24.1, which may be responsible for the key features of maternal UPD(16). In aim 1, we will study the role of genomic imprinting of the FOXF1 locus in ACDMPV and UPD(16). In aim 2, we will analyze the function of the FOXF1 enhancer, including the overlapping lncRNAs. In aim 3, we will investigate the function of FENDRR in development and disease of heart, lung, and placenta. The proposed studies would provide a better understanding of the function of distant tissue-specific enhancers in genomic imprinting and the development and disease. This proposal would also elucidate the role of lncRNAs in enhancer function and gene regulation in general, and provide knowledge on this class of promising therapeutic targets.