135 results found
Braun T, Sosnovski KE, Amir A, et al., 2023, Mucosal transcriptomics highlight lncRNAs implicated in ulcerative colitis, Crohn's disease, and celiac disease, JCI INSIGHT, Vol: 8
Walters R, Vasilaki E, Aman J, et al., 2023, SOX17 enhancer variants disrupt transcription factor binding and enhancer inactivity drives pulmonary hypertension, Circulation, Vol: 147, Pages: 1606-1621, ISSN: 0009-7322
BACKGROUND: Pulmonary arterial hypertension (PAH) is a rare disease characterized by remodeling of the pulmonary arteries, increased vascular resistance, and right-sided heart failure. Genome-wide association studies of idiopathic/heritable PAH established novel genetic risk variants, including conserved enhancers upstream of transcription factor (TF) SOX17 containing 2 independent signals. SOX17 is an important TF in embryonic development and in the homeostasis of pulmonary artery endothelial cells (hPAEC) in the adult. Rare pathogenic mutations in SOX17 cause heritable PAH. We hypothesized that PAH risk alleles in an enhancer region impair TF-binding upstream of SOX17, which in turn reduces SOX17 expression and contributes to disturbed endothelial cell function and PAH development. METHODS: CRISPR manipulation and siRNA were used to modulate SOX17 expression. Electromobility shift assays were used to confirm in silico-predicted TF differential binding to the SOX17 variants. Functional assays in hPAECs were used to establish the biological consequences of SOX17 loss. In silico analysis with the connectivity map was used to predict compounds that rescue disturbed SOX17 signaling. Mice with deletion of the SOX17-signal 1 enhancer region (SOX17-4593/enhKO) were phenotyped in response to chronic hypoxia and SU5416/hypoxia. RESULTS: CRISPR inhibition of SOX17-signal 2 and deletion of SOX17-signal 1 specifically decreased SOX17 expression. Electromobility shift assays demonstrated differential binding of hPAEC nuclear proteins to the risk and nonrisk alleles from both SOX17 signals. Candidate TFs HOXA5 and ROR-α were identified through in silico analysis and antibody electromobility shift assays. Analysis of the hPAEC transcriptomes revealed alteration of PAH-relevant pathways on SOX17 silencing, including extracellular matrix regulation. SOX17 silencing in hPAECs resulted in increased apoptosis, proliferation, and disturbance of barrier function. With the use of t
De Vas M, Boulet F, Joshi SS, et al., 2023, Regulatory de novo mutations underlying intellectual disability, Life Science Alliance, Vol: 6, Pages: 1-16, ISSN: 2575-1077
The genetic aetiology of a major fraction of patients with intellectual disability (ID) remains unknown. De novo mutations (DNMs) in protein-coding genes explain up to 40% of cases, but the potential role of regulatory DNMs is still poorly understood. We sequenced 63 whole genomes from 21 ID probands and their unaffected parents. In addition, we analysed 30 previously sequenced genomes from exome-negative ID probands. We found that regulatory DNMs were selectively enriched in fetal brain-specific enhancers as compared with adult brain enhancers. DNM-containing enhancers were associated with genes that show preferential expression in the prefrontal cortex. Furthermore, we identified recurrently mutated enhancer clusters that regulate genes involved in nervous system development (CSMD1, OLFM1, and POU3F3). Most of the DNMs from ID probands showed allele-specific enhancer activity when tested using luciferase assay. Using CRISPR-mediated mutation and editing of epigenomic marks, we show that DNMs at regulatory elements affect the expression of putative target genes. Our results, therefore, provide new evidence to indicate that DNMs in fetal brain-specific enhancers play an essential role in the aetiology of ID.
Magenheim J, Maestro MA, Sharon N, et al., 2023, Matters arising: Insufficient evidence that pancreatic b cells are derived from adult ductal Neurog3-expressing progenitors, CELL STEM CELL, Vol: 30, Pages: 488-+, ISSN: 1934-5909
Costanzo MC, von Grotthuss M, Massung J, et al., 2023, The Type 2 Diabetes Knowledge Portal: an open access genetic resource dedicated to type 2 diabetes and related traits, Cell Metabolism, Vol: 35, Pages: 695-710.e6, ISSN: 1550-4131
Associations between human genetic variation and clinical phenotypes have become a foundation of biomedical research. Most repositories of these data seek to be disease-agnostic and therefore lack disease-focused views. The Type 2 Diabetes Knowledge Portal (T2DKP) is a public resource of genetic datasets and genomic annotations dedicated to type 2 diabetes (T2D) and related traits. Here, we seek to make the T2DKP more accessible to prospective users and more useful to existing users. First, we evaluate the T2DKP's comprehensiveness by comparing its datasets with those of other repositories. Second, we describe how researchers unfamiliar with human genetic data can begin using and correctly interpreting them via the T2DKP. Third, we describe how existing users can extend their current workflows to use the full suite of tools offered by the T2DKP. We finally discuss the lessons offered by the T2DKP toward the goal of democratizing access to complex disease genetic results.
Allesoe RL, Lundgaard AT, Medina RH, et al., 2023, Discovery of drug-omics associations in type 2 diabetes with generative deep-learning models, NATURE BIOTECHNOLOGY, Vol: 41, Pages: 399-+, ISSN: 1087-0156
Juan-Mateu J, Bajew S, Miret-Cuesta M, et al., 2023, Pancreatic microexons regulate islet function and glucose homeostasis, NATURE METABOLISM, Vol: 5, Pages: 219-+
Dawed AY, Mari A, Brown A, et al., 2023, Pharmacogenomics of GLP-1 receptor agonists: a genome-wide analysis of observational data and large randomised controlled trials, LANCET DIABETES & ENDOCRINOLOGY, Vol: 11, Pages: 33-41, ISSN: 2213-8587
Zaugg JB, Sahlen P, Andersson R, et al., 2022, Current challenges in understanding the role of enhancers in disease, NATURE STRUCTURAL & MOLECULAR BIOLOGY, Vol: 29, Pages: 1148-1158, ISSN: 1545-9993
De Vas MG, Boulet F, Joshi SS, et al., 2022, Regulatory<i>de novo</i>mutations underlying intellectual disability
<jats:title>Abstract</jats:title><jats:p>The genetic aetiology of a major fraction of patients with intellectual disability (ID) remains unknown.<jats:italic>De novo</jats:italic>mutations (DNMs) in protein-coding genes explain up to 40% of cases, but the potential role of regulatory DNMs is still poorly understood. We sequenced 63 whole genomes from 21 ID probands and their unaffected parents (trio). Additionally, we analysed 30 previously sequenced genomes from exome-negative ID probands. We found that regulatory DNMs were selectively enriched in fetal brain-specific and human-gained enhancers. DNM-containing enhancers were associated with genes that show preferential expression in the pre-frontal cortex, have been previously implicated in ID or related disorders, and exhibit intolerance to loss of function mutations. Moreover, we found that highly interacting regulatory regions from intermediate progenitor cells of the developing human cortex were strongly enriched for ID DNMs. Furthermore, we identified recurrently mutated enhancer clusters that regulate genes involved in nervous system development (<jats:italic>CSMD1, OLFM1</jats:italic>, and<jats:italic>POU3F3)</jats:italic>. The majority of the DNMs from ID probands showed allele-specific enhancer activity when tested using luciferase assay. Using CRISPR-mediated mutation and editing of epigenomic marks, we show that regulatory elements harbouring DNMs indeed function as enhancers and DNMs at regulatory elements affect the expression of putative target genes. Our results, therefore, provide new evidence to indicate that DNMs in fetal brain-specific enhancers play an essential role in the aetiology of ID.</jats:p>
Beucher A, Miguel Escalada I, Balboa D, et al., 2022, HASTER lncRNA promoter is a cis-acting transcriptional stabilizer of HNF1A, Nature Cell Biology, Vol: 24, Pages: 1528-1540, ISSN: 1465-7392
The biological purpose of long non-coding RNAs (lncRNAs) is poorly understood. Haploinsufficient mutations in HNF1A homeobox A (HNF1A), encoding a homeodomain transcription factor, cause diabetes mellitus. Here, we examine HASTER, the promoter of an lncRNA antisense to HNF1A. Using mouse and human models, we show that HASTER maintains cell-specific physiological HNF1A concentrations through positive and negative feedback loops. Pancreatic β cells from Haster mutant mice consequently showed variegated HNF1A silencing or overexpression, resulting in hyperglycaemia. HASTER-dependent negative feedback was essential to prevent HNF1A binding to inappropriate genomic regions. We demonstrate that the HASTER promoter DNA, rather than the lncRNA, modulates HNF1A promoter–enhancer interactions in cis and thereby regulates HNF1A transcription. Our studies expose a cis-regulatory element that is unlike classic enhancers or silencers, it stabilizes the transcription of its target gene and ensures the fidelity of a cell-specific transcription factor program. They also show that disruption of a mammalian lncRNA promoter can cause diabetes mellitus.
Atla G, Bonas-Guarch S, Cuenca-Ardura M, et al., 2022, Genetic regulation of RNA splicing in human pancreatic islets, Genome Biology, Vol: 23, Pages: 1-28, ISSN: 1474-7596
Background: Non‑coding genetic variants that influence gene transcription in pancreatic islets play a major role in the susceptibility to type 2 diabetes (T2D), and likely also contribute to type 1 diabetes (T1D) risk. For many loci, however, the mechanisms through which non‑coding variants influence diabetes susceptibility are unknown. Results: We examine splicing QTLs (sQTLs) in pancreatic islets from 399 human donors and observe that genetic variation has a widespread influence on splicing of genes with established roles in islet biology and diabetes. In parallel, we profile expression QTLs (eQTLs) and use transcriptome‑wide association as well as genetic co‑localization studies to assign islet sQTLs or eQTLs to T2D and T1D susceptibility signals, many of which lack candidate effector genes. This analysis reveals biologically plausible mechanisms, including the association of T2D with an sQTL that creates a nonsense isoform in ERO1B, a regulator of ER‑stress and proinsulin biosynthesis. The expanded list of T2D risk effector genes reveals overrepresented pathways, including regulators of G‑protein‑mediated cAMP production. The analysis of sQTLs also reveals candidate effector genesfor T1D susceptibility such as DCLRE1B, a senescence regulator, and lncRNA MEG3.Conclusions: These data expose widespread effects of common genetic variants on RNA splicing in pancreatic islets. The results support a role for splicing variation in diabetes susceptibility, and offer a new set of genetic targets with potential therapeutic benefit.
Cuenca-Ardura M, De Vas M, Balboa D, et al., 2022, Genome-wide CRISPR screens identify therapeutic targets for HNF1A-deficient diabetes, Publisher: SPRINGER, Pages: S162-S162, ISSN: 0012-186X
Miguel-Escalada I, Maestro MÁ, Balboa D, et al., 2022, Pancreas agenesis mutations disrupt a lead enhancer controlling a developmental enhancer cluster., Developmental Cell, Vol: 57, Pages: 1922-1936.e9, ISSN: 1534-5807
Sequence variants in cis-acting enhancers are important for polygenic disease, but their role in Mendelian disease is poorly understood. Redundancy between enhancers that regulate the same gene is thought to mitigate the pathogenic impact of enhancer mutations. Recent findings, however, have shown that loss-of-function mutations in a single enhancer near PTF1A cause pancreas agenesis and neonatal diabetes. Using mouse and human genetic models, we show that this enhancer activates an entire PTF1A enhancer cluster in early pancreatic multipotent progenitors. This leading role, therefore, precludes functional redundancy. We further demonstrate that transient expression of PTF1A in multipotent progenitors sets in motion an epigenetic cascade that is required for duct and endocrine differentiation. These findings shed insights into the genome regulatory mechanisms that drive pancreas differentiation. Furthermore, they reveal an enhancer that acts as a regulatory master key and is thus vulnerable to pathogenic loss-of-function mutations.
Fukunaga Y, Fukuda A, Omatsu M, et al., 2022, Loss of Arid1a and Pten in Pancreatic Ductal Cells Induces Intraductal Tubulopapillary Neoplasm via the YAP/TAZ Pathway, GASTROENTEROLOGY, Vol: 163, Pages: 466-+, ISSN: 0016-5085
Nagao M, Fukuda A, Omatsu M, et al., 2022, Concurrent Activation of Kras and Canonical Wnt Signaling Induces Premalignant Lesions That Progress to Extrahepatic Biliary Cancer in Mice., Cancer Res, Vol: 82, Pages: 1803-1817
UNLABELLED: Biliary cancer has long been known to carry a poor prognosis, yet the molecular pathogenesis of carcinoma of the extrahepatic biliary system and its precursor lesions remains elusive. Here we investigated the role of Kras and canonical Wnt pathways in the tumorigenesis of the extrahepatic bile duct (EHBD) and gall bladder (GB). In mice, concurrent activation of Kras and Wnt pathways induced biliary neoplasms that resembled human intracholecystic papillary-tubular neoplasm (ICPN) and biliary intraepithelial neoplasia (BilIN), putative precursors to invasive biliary cancer. At a low frequency, these lesions progressed to adenocarcinoma in a xenograft model, establishing them as precancerous lesions. Global gene expression analysis revealed increased expression of genes associated with c-Myc and TGFβ pathways in mutant biliary spheroids. Silencing or pharmacologic inhibition of c-Myc suppressed proliferation of mutant biliary spheroids, whereas silencing of Smad4/Tgfbr2 or pharmacologic inhibition of TGFβ signaling increased proliferation of mutant biliary spheroids and cancer formation in vivo. Human ICPNs displayed activated Kras and Wnt signals and c-Myc and TGFβ pathways. Thus, these data provide direct evidence that concurrent activation of the Kras and canonical Wnt pathways results in formation of ICPN and BilIN, which could develop into biliary cancer. SIGNIFICANCE: This work shows how dysregulation of canonical cell growth pathways drives precursors to biliary cancers and identifies several molecular vulnerabilities as potential therapeutic targets in these precursors to prevent oncogenic progression.
Mahajan A, Spracklen CN, Zhang W, et al., 2022, Multi-ancestry genetic study of type 2 diabetes highlights the power of diverse populations for discovery and translation, NATURE GENETICS, Vol: 54, Pages: 560-+, ISSN: 1061-4036
Alonso L, Piron A, Moran I, et al., 2021, TIGER: The gene expression regulatory variation landscape of human pancreatic islets, CELL REPORTS, Vol: 37, ISSN: 2211-1247
Rovira M, Maestro MA, Grau V, et al., 2021, <i>Hnf1b</i>-CreER causes efficient recombination of a Rosa26-RFP reporter in duct and islet δ cells, ISLETS, Vol: 13, Pages: 134-139, ISSN: 1938-2014
Rovira M, Atla G, Maestro MA, et al., 2021, REST is a major negative regulator of endocrine differentiation during pancreas organogenesis, Genes & Development, Vol: 35, Pages: 1229-1242, ISSN: 0890-9369
Multiple transcription factors have been shown to promote pancreatic β-cell differentiation, yet much less is known about negative regulators. Earlier epigenomic studies suggested that the transcriptional repressor REST could be a suppressor of endocrinogenesis in the embryonic pancreas. However, pancreatic Rest knockout mice failed to show abnormal numbers of endocrine cells, suggesting that REST is not a major regulator of endocrine differentiation. Using a different conditional allele that enables profound REST inactivation, we observed a marked increase in pancreatic endocrine cell formation. REST inhibition also promoted endocrinogenesis in zebrafish and mouse early postnatal ducts and induced β-cell-specific genes in human adult duct-derived organoids. We also defined genomic sites that are bound and repressed by REST in the embryonic pancreas. Our findings show that REST-dependent inhibition ensures a balanced production of endocrine cells from embryonic pancreatic progenitors.
Bevacqua RJ, Dai X, Lam JY, et al., 2021, CRISPR-based genome editing in primary human pancreatic islet cells, NATURE COMMUNICATIONS, Vol: 12
Akerman I, Maestro MA, De Franco E, et al., 2021, Neonatal diabetes mutations disrupt a chromatin pioneering function that activates the human insulin gene, CELL REPORTS, Vol: 35, ISSN: 2211-1247
Akerman I, Maestro MA, Grau V, et al., 2021, Neonatal diabetes mutations disrupt a chromatin pioneering function that activates the human insulin gene, Cell Reports, ISSN: 2211-1247
<h4>ABSTRACT</h4> Despite the central role of chromosomal context in gene transcription, human noncoding DNA variants are generally studied outside of their endogenous genomic location. This poses major limitations to understand the true consequences of causal regulatory variants. We focused on a cis-regulatory mutation (c.-331C>G) in the INS gene promoter that is recurrently mutated in unrelated patients with recessive neonatal diabetes. We created mice in which a ~3.1 kb human INS upstream region carrying −331C or −331G alleles replaced the orthologous mouse Ins2 region. This human sequence drove cell-specific transcription in mice. It also recapitulated poised chromatin during pancreas development and active chromatin in differentiated β-cells. The c.-331C>G mutation, however, blocked active chromatin formation in differentiated b-cells. We further show that another neonatal diabetes gene product, GLIS3, had a singular pioneer-like ability to activate INS chromatin in non-pancreatic cells, which was hampered by the c.-331C>G mutation. This in vivo analysis of human regulatory defects, therefore, uncovered cis and trans components of a mechanism that is essential to activate the endogenous INS gene.
Bizzotto R, Jennison C, Jones AG, et al., 2021, Processes Underlying Glycemic Deterioration in Type 2 Diabetes: An IMI DIRECT Study, DIABETES CARE, Vol: 44, Pages: 511-518, ISSN: 0149-5992
Bar N, Korem T, Weissbrod O, et al., 2020, A reference map of potential determinants for the human serum metabolome, NATURE, Vol: 588, Pages: 135-140, ISSN: 0028-0836
Wessel J, Majarian TD, Highland HM, et al., 2020, Rare Non-coding Variation Identified by Large Scale Whole Genome Sequencing Reveals Unexplained Heritability of Type 2 Diabetes
<jats:p>Type 2 diabetes is increasing in all ancestry groups<jats:sup>1</jats:sup>. Part of its genetic basis may reside among the rare (minor allele frequency <0.1%) variants that make up the vast majority of human genetic variation<jats:sup>2</jats:sup>. We analyzed high-coverage (mean depth 38.2x) whole genome sequencing from 9,639 individuals with T2D and 34,994 controls in the NHLBI’s Trans-Omics for Precision Medicine (TOPMed) program<jats:sup>2</jats:sup> to show that rare, non-coding variants that are poorly captured by genotyping arrays or imputation panels contribute h<jats:sup>2</jats:sup>=53% (P=4.2×10<jats:sup>−5</jats:sup>) to the genetic component of risk in the largest (European) ancestry subset. We coupled sequence variation with islet epigenomic signatures<jats:sup>3</jats:sup> to annotate and group rare variants with respect to gene expression<jats:sup>4</jats:sup>, chromatin state<jats:sup>5</jats:sup> and three-dimensional chromatin architecture<jats:sup>6</jats:sup>, and show that pancreatic islet regulatory elements contribute to T2D genetic risk (h<jats:sup>2</jats:sup>=8%, P=2.4×10<jats:sup>−3</jats:sup>). We used islet annotation to create a non-coding framework for rare variant aggregation testing. This approach identified five loci containing rare alleles in islet regulatory elements that suggest novel biological mechanisms readily linked to hypotheses about variant-to-function. Large scale whole genome sequence analysis reveals the substantial contribution of rare, non-coding variation to the genetic architecture of T2D and highlights the value of tissue-specific regulatory annotation for variant-to-function discovery.</jats:p>
Mahajan A, Spracklen CN, Zhang W, et al., 2020, Trans-ancestry genetic study of type 2 diabetes highlights the power of diverse populations for discovery and translation
<jats:title>ABSTRACT</jats:title><jats:p>We assembled an ancestrally diverse collection of genome-wide association studies of type 2 diabetes (T2D) in 180,834 cases and 1,159,055 controls (48.9% non-European descent). We identified 277 loci at genome-wide significance (<jats:italic>p</jats:italic><5×10<jats:sup>-8</jats:sup>), including 237 attaining a more stringent trans-ancestry threshold (<jats:italic>p</jats:italic><5×10<jats:sup>-9</jats:sup>), which were delineated to 338 distinct association signals. Trans-ancestry meta-regression offered substantial enhancements to fine-mapping, with 58.6% of associations more precisely localised due to population diversity, and 54.4% of signals resolved to a single variant with >50% posterior probability. This improved fine-mapping enabled systematic assessment of candidate causal genes and molecular mechanisms through which T2D associations are mediated, laying foundations for functional investigations. Trans-ancestry genetic risk scores enhanced transferability across diverse populations, providing a step towards more effective clinical translation to improve global health.</jats:p>
Kalisz M, Bernardo E, Beucher A, et al., 2020, HNF1A recruits KDM6A to activate differentiated acinar cell programs that suppress pancreatic cancer, The EMBO Journal, Vol: 39, ISSN: 0261-4189
Defects in transcriptional regulators of pancreatic exocrine differentiation have been implicated in pancreatic tumorigenesis, but the molecular mechanisms are poorly understood. The locus encoding the transcription factor HNF1A harbors susceptibility variants for pancreatic ductal adenocarcinoma (PDAC), while KDM6A, encoding Lysine-specific demethylase 6A, carries somatic mutations in PDAC. Here, we show that pancreas-specific Hnf1a null mutant transcriptomes phenocopy those of Kdm6a mutations, and both defects synergize with KrasG12D to cause PDAC with sarcomatoid features. We combine genetic, epigenomic, and biochemical studies to show that HNF1A recruits KDM6A to genomic binding sites in pancreatic acinar cells. This remodels the acinar enhancer landscape, activates differentiated acinar cell programs, and indirectly suppresses oncogenic and epithelial-mesenchymal transition genes. We also identify a subset of non-classical PDAC samples that exhibit the HNF1A/KDM6A-deficient molecular phenotype. These findings provide direct genetic evidence that HNF1A deficiency promotes PDAC. They also connect the tumor-suppressive role of KDM6A deficiency with a cell-specific molecular mechanism that underlies PDAC subtype definition.
Baeyens L, Lemper M, Leuckx G, et al., 2020, Transient cytokine treatment induces acinar cell reprogramming and regenerates functional beta cell mass in diabetic mice (Retraction of Vol 32, Pg 76, 2019), NATURE BIOTECHNOLOGY, Vol: 38, Pages: 374-374, ISSN: 1087-0156
Palomer X, Silvia Roman-Azcona M, Pizarro-Delgado J, et al., 2020, SIRT3-mediated inhibition of FOS through histone H3 deacetylation prevents cardiac fibrosis and inflammation, Signal Transduction and Targeted Therapy, Vol: 5, Pages: 1-10, ISSN: 2095-9907
Sirtuin 3 (SIRT3) is a deacetylase that modulates proteins that control metabolism and protects against oxidative stress. Modulation of SIRT3 activity has been proposed as a promising therapeutic target for ameliorating metabolic diseases and associated cardiac disturbances. In this study, we investigated the role of SIRT3 in inflammation and fibrosis in the heart using male mice with constitutive and systemic deletion of SIRT3 and human cardiac AC16 cells. SIRT3 knockout mice showed cardiac fibrosis and inflammation that was characterized by augmented transcriptional activity of AP-1. Consistent with this, SIRT3 overexpression in human and neonatal rat cardiomyocytes partially prevented the inflammatory and profibrotic response induced by TNF-α. Notably, these effects were associated with a decrease in the mRNA and protein levels of FOS and the DNA-binding activity of AP-1. Finally, we demonstrated that SIRT3 inhibits FOS transcription through specific histone H3 lysine K27 deacetylation at its promoter. These findings highlight an important function of SIRT3 in mediating the often intricate profibrotic and proinflammatory responses of cardiac cells through the modulation of the FOS/AP-1 pathway. Since fibrosis and inflammation are crucial in the progression of cardiac hypertrophy, heart failure, and diabetic cardiomyopathy, our results point to SIRT3 as a potential target for treating these diseases.
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