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Furey, T. S.

Publications and source records attributed to Furey, T. S..

12 recordsLinked to original sources

Transcriptome-wide Differential Expression and Splicing in Inflammatory Bowel Disease Patients

The inflammatory bowel diseases (IBD), comprising mainly Crohn's disease (CD) and ulcerative colitis (UC), are characterized by chronic intestinal inflammation driven in part by complex genetic and gene regulatory mechanisms. Although transcriptomic studies have defined broad expression changes in IBD, the contribution of alternative splicing to disease-associated molecular variation remains less clear. We therefore integrated differential expression (DE) and differential splicing (DS) analyses in macroscopically uninvolved colonic mucosal biopsies from patients with either CD or UC along with non-IBD controls to define gene expression and intron-usage changes across disease subtypes. We identified 491 DS and 316 DE genes in CD vs. non-IBD, and 1,298 DS and 1,107 DE genes in UC vs. non-IBD. DS and DE genes were nearly mutually exclusive, with no overlapping genes in CD and 16 in UC. Consistent with this result, pathway analysis showed that differentially expressed and differentially spliced genes were associated with related but distinct biological programs. DE genes were involved in chromatin organization, transcriptional regulation, and metabolic pathways for glycans and drugs, whereas DS genes were enriched for splicing, cellular signaling, and lipid metabolism. We found substantial similarity in enriched pathways across CD and UC with some notable exceptions, including increased enrichment of DS and DE genes involved in extracellular vesicles and exosomes in CD and enrichment of DS genes in ER-to-Golgi trafficking and stress granules in UC. Direct comparisons of CD and UC patients additionally show differential splicing usage in genes involved in cell adhesion pathways. These findings identify alternative splicing as a major contributor to transcriptomic changes in IBD that is largely distinct from changes in expression level and provide a broader view of molecular contributors to IBD.

genomics↗

Fatty Acid Oxidation Suppression Reprograms Fibroblasts in Fibrostenotic Crohns Disease

Fibrostenotic complications represent a major cause of morbidity in Crohns disease (CD), yet the cellular mechanisms that drive intestinal fibrosis independent of active inflammation remain poorly understood. Here, we identify impaired fatty acid oxidation (FAO) as a defining metabolic feature of fibroblasts in fibrostenotic CD. Untargeted lipidomics of non-inflamed colonic tissue from CD patients demonstrated enrichment of triacylglycerols and long-chain acylcarnitines, suggesting altered lipid utilization. Across three independent RNA-sequencing cohorts, including treatment-naive pediatric ileal biopsies, FAO genes (CPT1A, CPT2, SLC25A20) were selectively downregulated in patients with or destined to develop fibrostenotic disease. Single-cell RNA-sequencing localized these transcriptional alterations specifically to fibroblasts within strictured ileum. Primary fibroblasts derived from fibrostenotic CD exhibited increased neutral lipid accumulation, impaired mitochondrial fatty acid trafficking, and diminished responsiveness to PPAR{gamma}-mediated suppression of TGF{beta}-induced myofibroblast activation. Together, these findings demonstrate that FAO impairment is a conserved, fibroblast-specific metabolic program associated with intestinal fibrosis in CD and suggest that metabolic modulation of stromal cells represents a potential therapeutic strategy for fibrostenotic disease.

genomics↗

Reference-guided Genome Assembly of Long Non-coding RNA Transcripts reveals Target Genes Associated With Crohn's Disease

Crohns disease (CD) is highly heterogeneous in presentation and progression with no cure. Molecular phenotyping has been used to elucidate cellular and tissue-based alterations to characterize drivers and effects of disease. One currently understudied class of functional molecules is long non-coding RNAs (lncRNAs). Studying the full lncRNA landscape in IBD is challenging due in part to an incomplete lncRNA annotation and a lack of their functional characterization in tissues of interest. We used a genome-guided alignment strategy to assemble predicted lncRNA transcripts using short RNA-sequencing data from colon tissue of adult patient samples. When combining our predicted lncRNAs with previous lncRNA annotations, we determined 98 that were differentially expressed, recapitulating many from previous IBD studies while also uncovering new ones. We built gene co-expression networks to cluster lncRNAs with functionally characterized protein-coding genes. Clusters containing differential lncRNAs were correlated to disease status and associated with pathways related to the humoral immune response, metabolism, and tissue regeneration. We uncovered multiple differential lncRNAs whose expression significantly correlated with nearby differential protein-coding genes that have also been differentially expressed in other IBD datasets, such as PITX2. We focused on a predicted lncRNA that is antisense to the PITX2-adjacent lncRNA PANCR, which we called PANCR-AS1, and provide multiple lines of evidence that support PANCR-AS1 functioning as an enhancer of PITX2 expression. Overall, we determined lncRNAs that are potential contributors to CD pathogenesis. We developed a robust pipeline for identifying lncRNAs in diseased and non-diseased tissue that are absent from reference annotations. We also outlined a framework to pinpoint significant disease-associated lncRNAs with potential functional activity related to their nearby protein-coding genes.

genomics↗

Liver single-nucleus multiome profiling reveals cell-type mechanisms for cardiometabolic traits

The liver is a central regulator of cardiometabolic physiology, coordinating processes such as lipid and glucose metabolism, protein synthesis, and detoxification. Genome-wide association studies (GWAS) have identified hundreds of genetic variants associated with cardiometabolic traits, yet their molecular mechanisms in liver cell types remain unclear. Using multiome single-nucleus RNA and ATAC sequencing on liver samples from 39 individuals, we profiled gene expression and chromatin accessibility in 68,398 nuclei across six primary liver cell types. We identified 306,706 accessible chromatin regions, including 70,884 regions undetected in bulk tissue analyses and that predominantly represent less abundant cell types. To identify genetic effects on gene regulation in liver cell types, we mapped quantitative trait loci (QTLs) and detected 1,885 chromatin accessibility QTLs (caQTLs) and 67 expression QTLs (eQTLs). We integrated cell-type QTLs with GWAS signals and revealed cell types, genes, and chromatin regulatory elements involved in cardiometabolic traits, such as liver enzyme and cholesterol levels. Non-hepatocyte cell-type QTL analyses exposed previously obscured mechanisms, such as an eQTL for ADAMTS12 in liver sinusoidal endothelial cells potentially involved in liver fibrosis, demonstrating that single-nucleus approaches can capture regulatory events missed in bulk analyses. Furthermore, we predicted cell type of action for bulk liver caQTLs colocalized with GWAS signals, enhancing mechanistic insights for complex trait associations. Our findings provide a high-resolution map of the hepatic regulatory landscape and advance the understanding of cellular contexts and molecular mechanisms underlying cardiometabolic traits.

genomics↗

Genome-Wide Uncertainty-Moderated Extraction of Signal Annotations from Multi-Sample Functional Genomics Data

Multi-sample functional genomics experiments should reveal reproducible regulatory activity, but locus- and sample-specific noise can obscure biological signals in sequencing data. We introduce Consenrich for genome-wide estimation of epigenomic signals across multiple samples. To encourage robustness and sensitivity, the state-space model underlying Consenrich accounts for positional observation variances to determine shrinkage toward predictions from a smooth process model over genomic coordinates. We first apply Consenrich to ATAC-seq and ChIP-seq datasets and demonstrate its ability for robust signal recovery. We then utilize Consenrich upstream of a class-imbalanced differential accessibility analysis in an Alzheimer's cohort of twenty samples and show that it improves the breadth of relevant biological insights. Software is available at https://github.com/nolan-h-hamilton/Consenrich.

genomics↗

eQTL in diseased colon tissue identifies novel target genes associated with IBD

Genome-wide association studies (GWAS) have identified over 300 loci associated with the inflammatory bowel diseases (IBD), but putative causal genes for most are unknown. We conducted the largest disease-focused expression quantitative trait loci (eQTL) analysis using colon tissue from 252 IBD patients to determine genetic effects on gene expression and potential contribution to IBD. Combined with two non-IBD colon eQTL studies, we identified 194 potential target genes for 108 GWAS loci. eQTL in IBD tissue were enriched for IBD GWAS loci colocalizations, provided novel evidence for IBD-associated genes such as ABO and TNFRSF14, and identified additional target genes compared to non-IBD tissue eQTL. IBD-associated eQTL unique to diseased tissue had distinct regulatory and functional characteristics with increased effect sizes. Together, these highlight the importance of eQTL studies in diseased tissue for understanding functional consequences of genetic variants, and elucidating molecular mechanisms and regulation of key genes involved in IBD.

genomics↗

Increased intestinal permeability in an orally-reactive peanut allergy model identifies Angiopoietin like-4 as a biomarker

Peanut allergy reaction severity correlates with increased intestinal epithelial cell (IEC) barrier permeability. CC027/GeniUnc mice develop peanut allergy by intragastric administration of peanut proteins without adjuvant. We report that peanut-allergic CC027/GeniUnc mice showed increased IEC barrier permeability and systemic peanut allergen Ara h 2 after challenge. Jejunal epithelial cell transcriptomics showed effects of peanut allergy on IEC proliferation, survival, and metabolism, and revealed IEC-predominant angiopoietin like-4 (Angptl4) as a unique feature of CC027/GeniUnc peanut allergy. CC027/GeniUnc mice and peanut-allergic pediatric patients demonstrated significantly higher serum Angptl4 and ANGPTL4 compared to control C3H/HeJ mice and non-peanut-allergic but atopic patients, respectively, highlighting its potential as a biomarker of peanut allergy.

cell biology↗

Integrative phenotypic and genomic analyses reveal strain-dependent responses to acute ozone exposure and their associations with airway macrophage transcriptional activity

Acute ozone (O3) exposure is associated with multiple adverse cardiorespiratory outcomes, the severity of which varies across human populations and rodent models from diverse genetic backgrounds. However, molecular determinants of response, including biomarkers that distinguish which individuals will develop more severe injury and inflammation (i.e., high responders), are poorly characterized. Here, we exposed adult, female and male mice from 6 strains, including 5 Collaborative Cross (CC) strains, to filtered air (FA) or 2 ppm O3 for 3 hours, and measured several inflammatory and injury parameters 21 hours later. Additionally, we collected airway macrophages and performed RNA-seq analysis to investigate influences of strain, treatment, and strain-by-treatment interactions on gene expression as well as transcriptional correlates of lung phenotypes. Animals exposed to O3 developed airway neutrophilia and lung injury, with varying degrees of severity. We identified many genes that were altered by O3 exposure across all strains, and examination of genes whose expression was influenced by strain-by-treatment interactions revealed prominent differences in response between the CC017/Unc and CC003/Unc strains, which were low- and high-responders, respectively (as measured by cellular inflammation and injury). Further investigation of this contrast indicated that baseline gene expression differences likely contribute to their divergent post-O3 exposure transcriptional responses. We also observed alterations in chromatin accessibility that differed by strain and with strain-by-treatment interactions, lending further plausibility that baseline differences can modulate post-exposure responses. Together, these results suggest that aspects of the respiratory response to O3 exposure may be mediated through altered airway macrophage transcriptional signatures, and further confirms the importance of gene-by-environment interactions in mediating differential responsiveness to environmental agents.

pharmacology and toxicology↗

Single-cell analysis of colonic epithelium reveals unexpected shifts in cellular composition and molecular phenotype in treatment-naiïve adult Crohn's disease

The intestinal epithelial barrier is comprised of a monolayer of specialized intestinal epithelial cells (IECs) that are critical in maintaining gut mucosal homeostasis. Dysfunction within various IEC fractions can increase intestinal permeability, resulting in a chronic and debilitating condition known as Crohns disease (CD). Defining the molecular changes in each IEC type in CD will contribute to an improved understanding of the pathogenic processes and the identification of potential therapeutic targets. Here we performed, for the first time at single-cell resolution, a direct comparison of the colonic epithelial cellular and molecular landscape between treatment-naive adult CD and non-IBD control patients. Our analysis revealed that in CD patients there is a significant skew in the colonic epithelial cellular distribution away from canonical LGR5+ stem cells, located at the crypt-bottom, and toward one specific subtype of mature colonocytes, located at the crypt-top. Further analysis revealed unique changes to gene expression programs in every major cell type, including a previously undescribed suppression in CD of most enteroendocrine driver genes as well as L-cell markers including GCG. We also dissect a previously poorly understood SPIB+ cell cluster, revealing at least four sub-clusters that exhibit unique features. One of these SPIB+ sub-clusters expresses crypt-top colonocyte markers and is significantly up-regulated in CD, whereas another sub-cluster strongly expresses and stains positive for lysozyme (albeit no other canonical Paneth cell marker), which surprisingly is greatly reduced in expression in CD. Finally, through integration with data from genome-wide association studies, we show that genes implicated in CD risk exhibit heretofore unknown cell-type specific patterns of aberrant expression in CD, providing unprecedented insight into the potential biological functions of these genes.

genomics↗

Decreased Colonic Activin Receptor Like Kinase 1 Disrupts Epithelial Barrier integrity and is associated with a poor clinical outcome in Crohns disease

ObjectiveIntestinal epithelial cell (IEC) barrier dysfunction is critical to the development of Crohns disease (CD). However, the mechanism is understudied. We recently reported increased microRNA-31-5p (miR-31-5p) expression in colonic IECs of CD patients, but downstream targets are unknown. DesignMiR-31-5p target genes were identified by integrative analysis of RNA- and small RNA-sequencing data from colonic mucosa and confirmed by qPCR in colonic IECs. Functional characterization of Activin Receptor-Like Kinase 1 (ACVRL1 or ALK1) in IECs was performed ex vivo using 2 dimensional-cultured human primary colonic IECs. The impact of altered colonic ALK1 signaling in CD for the risk of surgery and endoscopic relapse was evaluated by a multivariate regression analysis and a Kaplan-Meier estimator. ResultsALK1 was identified as a target of miR-31-5p in colonic IECs of CD patients and confirmed using a 3-UTR reporter assay. Activation of ALK1 restricted the proliferation of colonic IECs in an EdU proliferation assay and down-regulated the expression of stemness-related genes. Activated ALK1 signaling directed the fate of colonic IEC differentiation toward colonocytes. Down-regulated ALK1 signaling was associated with increased stemness and decreased colonocyte-specific marker expression in colonic IECs of CD patients compared to healthy controls. Activation of ALK1 enhanced epithelial barrier integrity in a trans-epithelial electrical resistance permeability assay. Lower colonic ALK1 expression was identified as an independent risk factor for surgery and associated with a higher risk of endoscopic relapse in CD patients. ConclusionDecreased colonic ALK1 disrupted colonic IEC barrier integrity and associated with deteriorated clinical outcomes in CD patients.

cell biology↗

Integrative QTL analysis of gene expression and chromatin accessibility identifies multi-tissue patterns of genetic regulation

Gene transcription profiles across tissues are largely defined by the activity of regulatory elements, most of which correspond to regions of accessible chromatin. Regulatory element activity is in turn modulated by genetic variation, resulting in variable transcription rates across individuals. The interplay of these factors, however, is poorly understood. Here we characterize expression and chromatin state dynamics across three tissues--liver, lung, and kidney--in 47 strains of the Collaborative Cross (CC) mouse population, examining the regulation of these dynamics by expression quantitative trait loci (eQTL) and chromatin QTL (cQTL). QTL whose allelic effects were consistent across tissues were detected for 1,101 genes and 133 chromatin regions. Also detected were eQTL and cQTL whose allelic effects differed across tissues, including local-eQTL for Pik3c2g detected in all three tissues but with distinct allelic effects. Leveraging overlapping measurements of gene expression and chromatin accessibility on the same mice from multiple tissues, we used mediation analysis to identify chromatin and gene expression intermediates of eQTL effects. Based on QTL and mediation analyses over multiple tissues, we propose a causal model for the distal genetic regulation of Akr1e1, a gene involved in glycogen metabolism, through the zinc finger transcription factor Zfp985 and chromatin intermediates. This analysis demonstrates the complexity of transcriptional and chromatin dynamics and their regulation over multiple tissues, as well as the value of the CC and related genetic resource populations for identifying specific regulatory mechanisms within cells and tissues.\n\nAuthor summaryGenetic variation can drive alterations in gene expression levels and chromatin accessibility, the latter of which defines gene regulatory elements genome-wide. The same genetic variants may associate with both molecular events, and these may be connected within the same causal path: a variant that reduces promoter region chromatin accessibility, potentially by affecting transcription factor binding, may lead to reduced expression of that gene. Moreover, these causal regulatory paths can differ between tissues depending on functions and cellular activity specific to each tissue. We identify cross-tissue and tissue-selective genetic regulators of gene expression and chromatin accessibility in liver, lung, and kidney tissues using a panel of genetically diverse inbred mouse strains. Further, we identify a number of candidate causal mediators of the genetic regulation of gene expression, including a zinc finger protein that helps silence the Akr1e1 gene. Our analyses are consistent with chromatin accessibility playing a role in the regulation of transcription. Our study demonstrates the power of genetically diverse, multi-parental mouse populations, such as the Collaborative Cross, for large-scale studies of genetic drivers of gene regulation that underlie complex phenotypes, as well as identifying causal intermediates that drive variable activity of specific genes and pathways.

genomics↗

Association Between Colonic Level of microRNA 31 and Subtypes of Adult and Pediatric Crohn’s Disease

Crohns disease (CD) is highly heterogeneous, due in large part to variability in cellular processes that underlie the natural history of CD, thereby confounding effective therapy. There is a critical need to advance understanding of the cellular mechanisms that drive CD heterogeneity. In this study, small RNA-sequencing and microRNA profiling in the colon revealed two distinct molecular subtypes, each with different clinical associations, in both adult and treatment-naive pediatric CD patients. Notably, we found that microRNA-31 (miR-31) expression by itself can stratify patients into these two subtypes. Through detailed analysis of several colonic mucosa cell types from adult patients, we found that differential levels of miR-31 are particularly pronounced in epithelial cells. We generated patient crypt-derived epithelial colonoids and showed that miR-31 expression differences preserved in this ex-vivo system. In adult patients, low colonic miR-31 expression levels at the time of surgery are associated with post-operative recurrence of ileal disease. In pediatric patients, lower miR-31 expression at the time of diagnosis is associated with the future development of fibrostenotic ileal CD requiring surgery. These findings represent an important step forward in designing more effective clinical trials and developing personalized therapies for CD.

genomics↗