Genome-wide association studies (GWAS) have identified >1,200 signals associated with type 2 diabetes (T2D), yet identifying functional variants remains challenging because the majority of them lie in noncoding regions of the genome and are in areas of high linkage disequilibrium (LD). While chromatin accessibility QTL (caQTL) and expression QTL (eQTL) analyses are useful for nominating regulatory mechanisms underlying GWAS signals, limitations still exist in pinpointing functional variants within regions of high LD. A complementary approach that has been less frequently applied is to focus on the allele-specific effect on chromatin accessibility at heterozygous single-nucleotide polymorphisms (SNPs), hereafter referred to as "allelic imbalance". We analyzed the allelic imbalance of reads generated from an assay for transposase-accessible chromatin with sequencing (ATAC-seq) across genotyped samples from 490 donors in T2D-relevant tissues: skeletal muscle, liver, pancreatic islets, adipose tissue, and relevant cell types. We identified 119,949 allelically imbalanced SNPs (FDR<0.05) across the genome. The allelic imbalance was often most prominent in one tissue and showed an enrichment overlapping with tissue-specific transcription factor (TF) binding footprints. Focusing on the 8,581 SNPs in previously published 99% credible sets from 338 T2D GWAS signals, we identified 256 imbalanced SNPs across 123 (36.4% of) signals, each showing allelic imbalance in at least one tissue or cell type. Of these, 71 signals contained only a single imbalanced SNP, representing excellent candidate causative variants. As a proof-of-concept, we showed that 23 of the 256 imbalanced SNPs were supported by allelic assays from previous studies. Further, we experimentally validated two imbalanced SNPs as likely functional variants: rs34584161 among a seven-SNP T2D credible set at the RNF6 signal in islets and rs849134 among a 13-SNP credible set at the JAZF1 signal in liver. This study demonstrates the power of integrating ATAC-seq allelic imbalance (ASAI) with GWAS statistical fine-mapping to identify candidate functional regulatory variants from among tightly linked GWAS variants in disease-relevant tissues. While applied here in T2D, this approach represents a widely applicable high-throughput framework for refining the genetic architecture of complex traits.
Approximately 30-40% of the human genome is anchored to the nuclear lamina through variably sized (10 kb-10 Mb) lamina-associated domains (LADs). Previous work in cultured murine and human cell lines indicate that LADs are not homogenous but can be classified into two subtypes (T1 and T2) based on levels of lamina-association. Due in part to technical limitations, the LAD substructure of neurons maturing in vivo is poorly understood. Here, we developed Genome Organization with CUT and Tag (GO-CaT) to map LAD substructure in neurons isolated from the midgestational human cortex and adult human brain. GO-CaT with LaminB1 antibodies mapped LADs with high efficiency as compared to other methods, and in prenatal neurons, we distinguished T1- and T2-LADs based on levels of LaminB1 enrichment. While T1-LADs had the transcriptional and epigenomic characteristics of cell type-invariant LADs including strong transcriptional repression, T2-LADs had a distinct epigenomic state that included enrichment of promoter-enhancer DNA interactions and intermediate levels of gene expression. In prenatal neurons, T2-LADs defined genomic regions that play key roles in neuronal development and were enriched for neurological GWAS phenotypes including those of human cognitive disorders. In a population of adult brain neurons, most prenatal T2-LADs were repositioned to either inter-LAD regions or further sequestered into T1-LADs, perhaps representing the completed, life-long spatial genome architecture of human neurons. These studies highlight the utility of GO-CaT for LAD subdomain mapping in cells isolated from human tissues and illustrate how the substructure of LADs may contribute to neural development, neuronal maturation, and human brain disease. ### Competing Interest Statement The authors have declared no competing interest.
AIMS:Hypertensive disorders of pregnancy (HDP) is a unique disease during gestational period, which is detrimental to pregnancy outcome. This study examined the clinical significance of long non-coding RNA GAS5 in gestational hypertension (GH) and preeclampsia (PE), aiming to explore potential biomarkers for the disease detection. METHODS:180 pregnant women with HPD including 90 cases with GH and 90 cases with PE, and another 100 healthy pregnant women were enrolled. Serum GAS5 levels were measured by RT-qPCR method. The diagnostic performance of GAS5 was assessed in GH and PE through plotting receiver operating characteristic (ROC) curve. Logistic regression was applied for the identification of independent factors. RESULTS:Elevated serum GAS5 was identified in GH patients, and its diagnostic performance in discriminating GH cases from healthy people was determined by ROC curve. Serum GAS5 was positively associated with SBP, DBP, LDL-C and CRP values. Cases with PE had an increased serum GAS5 level relative to those with GH. Serum GAS5 was identified to be an independent predictor for PE, and can differentiate PE cases from GH ones. with a good diagnositc performance. Cases with high levels of serum GAS5 had a high risk of poor pregnancy outcomes. CONCLUSION:Elevated serum GAS5 could serve as an effective diagnostic biomarker in discriminating GH patients from healthy people by first trimester screening. Detection of serum GAS5 level has a certain predictive value for PE.
Cis-regulatory elements are coordinated to regulate the expression of their targeted genes. However, the joint measurement of cis-regulatory elements' activities and their interactions in spatial proximity is limited by the current sequencing approaches. We describe a method, NOMe-HiC, which simultaneously captures single-nucleotide polymorphisms, DNA methylation, chromatin accessibility (GpC methyltransferase footprints), and chromosome conformation changes from the same DNA molecule, together with the transcriptome, in a single assay. NOMe-HiC shows high concordance with state-of-the-art mono-omic assays across different molecular measurements and reveals coordinated chromatin accessibility at distal genomic segments in spatial proximity and novel types of long-range allele-specific chromatin accessibility.
BACKGROUND:Preterm birth (PTB), defined as delivery before 37 gestational weeks, imposes significant public health burdens. A recent maternal genome-wide association study of spontaneous PTB identified a noncoding locus near the angiotensin II receptor type 2 (AGTR2) gene. Genotype-Tissue Expression data revealed that alleles associated with decreased AGTR2 expression in the uterus were linked to an increased risk of PTB and shortened gestational duration. We hypothesized that a causative variant in this locus modifies AGTR2 expression by altering transcription factor (TF) binding.METHODS:To investigate this hypothesis, we performed bioinformatics analyses and functional characterizations at the implicated locus. Potential causal single nucleotide polymorphisms (SNPs) were prioritized, and allele-dependent binding of TFs was predicted. Reporter assays were employed to assess the enhancer activity of the top PTB-associated non-coding variant, rs7889204, and its impact on TF binding.RESULTS:Our analyses revealed that rs7889204, a top PTB-associated non-coding genetic variant is one of the strongest eQTLs for the AGTR2 gene in uterine tissue samples. We observed differential binding of CEBPB (CCAAT enhancer binding protein beta) and HOXA10 (homeobox A10) to the alleles of rs7889204. Reporter assays demonstrated decreased enhancer activity for the rs7889204 risk "C" allele.CONCLUSION:Collectively, these results demonstrate that decreased AGTR2 expression caused by reduced transcription factor binding increases the risk for PTB and suggest that enhancing AGTR2 activity may be a preventative measure in reducing PTB risk.
: 24 Cis-regulatory elements (CREs) coordinate to regulate the expression of their targeted genes, up 25 to megabases away. However, the joint measurement of CREs’ activities and their interactions 26 over large genomic distances is limited by the current sequencing approaches. We report a 27 method, GTAGMe-seq, which simultaneously captures the single nucleotide polymorphisms, 28 DNA methylation, GpC methyltransferase footprints, and chromosome conformation changes 29 from the same DNA molecules, together with transcriptome in the same assay. GTAGMe-seq 30 shows high concordance with the state-of-art mono-omics assays across different molecular 31 measurements. It reveals the coordinated GpC methyltransferase footprints at distal genomic 32 segments in spatial proximity and different types of long-range allele-specific methyltransferase 33 footprints. 34
Background: Ovarian carcinoma (OC) is the deadliest gynecologic malignancy in females worldwide. Circular RNA Foxo3 (Foxo3) plays essential roles in various cancers. However, the detailed function of Foxo3 in OC remains unclear. This study aimed to investigate the role of Foxo3 in OC and the underlying molecular mechanism. Methods: The abundance of Foxo3 was detected in OC cell lines by qPCR. Lentivirus transduction, CCK-8, wound healing assays, transwell migration and invasion assays, luciferase reporter assay, western blotting, fluorescence in situ hybridization (FISH), transmission electron microscopy, nanoparticle tracking analysis, and bioinformatics analysis were performed to investigate the underlying mechanism. Results: The results demonstrated that Foxo3 was significantly upregulated in OC cell lines. Overexpression and knockdown of Foxo3 promoted and inhibited the proliferation, migration, and invasion of OC cells, respectively. Foxo3 could bind to miR-422a to negatively regulate miR-422a expression. Also, proteolipid protein 2 (PLP2) was a targeting gene of miR-422a. Additionally, Foxo3 was highly expressed in exosomes derived from OC cells. Furthermore, Foxo3 could be shuttled to OC cells by exosomes and promoted OC progression. Conclusions: Foxo3 promoted OC progression through exosome-mediated intercellular interaction to target miR-422a/PLP2 axis. Foxo3 may serve as a potential biomarker for OC.