Rare-intronic-variants-of-TCF7L2
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ABSTRACT:
PROVIDER: PRJEB13132 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| ERR1333715.fastq.gz | Fastqsanger.gz |
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Project description:TCF7L2 is one of the strongest type 2 diabetes (T2DM) candidate genes to emerge from GWAS studies, but the mechanisms by which it regulates the pathways which are important in the pathogenesis of type 2 diabetes are unknown. Previous in vitro and in vivo studies have focused on the link between TCF7L2 and insulin secretion as an explanation for the association between TCF7L2 and T2DM. However, TCF7L2 and the Wnt/β-catenin pathway are important for metabolic zonation in the liver. This raises the interesting possibility that TCF7L2 may influence glucose homeostasis by regulating hepatic glucose production (HGP). To examine this question, we utilized the H4IIE cell as a model of HGP. Inhibition of HGP in H4IIE cells from lactate and pyruvate was highly sensitive to physiological concentrations of insulin and metformin. Silencing of TCF7L2 protein expression induced a 5-fold increase in basal HGP (P<0.0001), and this was accompanied by marked increase in the expression of several key gluconeogenic genes. FBPase, PEPCK and G6Pase mRNA were up-regulated 2.5-fold (P<0.0001), 1.4-fold (P<0.01) and 2.3-fold (P<0.0001), respectively, compared to scramble siRNA. Compared to their respective baseline values, insulin and metformin suppressed HGP equally in the scramble and TCF7L2 siRNA cells, but HGP remained elevated in TCF7L2 silenced cells due to the increased baseline HGP. Using chromatin immunoprecipitation sequencing (ChIP-Seq), we investigated the direct transcriptional targets of TCF7L2 in hepatocytes. A total of 2119 ChIP peaks were detected, of which 36% were located inside gene boundaries and, overall, a total of 65% of all binding events were within 50 Kb of a gene. De novo motif analysis revealed remarkable conservation of the long and short TCF7L2 consensus binding sites in the rat hepatocytes. Pathway analysis showed that the top two disease categories over-represented in our dataset were “non-insulin dependent diabetes” (155 genes; P = 1.63 x 10-10) and “diabetes mellitus” (245 genes; P = 7.4 x 10-12). Inspection of genes in these categories revealed that TCF7L2 directly binds to multiple genes important in the regulation of glucose metabolism in the liver, including PEPCK, FBP1, IRS1, IRS2, AKT2 ADIPOR1, PDK4 and CPT1A. Our findings suggest a novel mechanism for the regulation of HGP by TCF7L2, and provide a possible explanation for the association of TCF7L2 polymorphisms with the incidence of T2DM. two samples: TCF7L2 ChIP-Seq and Input DNA
2011-09-12 | E-GEOD-28782 | biostudies-arrayexpress
Project description:TCF7L2 is one of the strongest type 2 diabetes (T2DM) candidate genes to emerge from GWAS studies, but the mechanisms by which it regulates the pathways which are important in the pathogenesis of type 2 diabetes are unknown. Previous in vitro and in vivo studies have focused on the link between TCF7L2 and insulin secretion as an explanation for the association between TCF7L2 and T2DM. However, TCF7L2 and the Wnt/β-catenin pathway are important for metabolic zonation in the liver. This raises the interesting possibility that TCF7L2 may influence glucose homeostasis by regulating hepatic glucose production (HGP). To examine this question, we utilized the H4IIE cell as a model of HGP. Inhibition of HGP in H4IIE cells from lactate and pyruvate was highly sensitive to physiological concentrations of insulin and metformin. Silencing of TCF7L2 protein expression induced a 5-fold increase in basal HGP (P<0.0001), and this was accompanied by marked increase in the expression of several key gluconeogenic genes. FBPase, PEPCK and G6Pase mRNA were up-regulated 2.5-fold (P<0.0001), 1.4-fold (P<0.01) and 2.3-fold (P<0.0001), respectively, compared to scramble siRNA. Compared to their respective baseline values, insulin and metformin suppressed HGP equally in the scramble and TCF7L2 siRNA cells, but HGP remained elevated in TCF7L2 silenced cells due to the increased baseline HGP. Using chromatin immunoprecipitation sequencing (ChIP-Seq), we investigated the direct transcriptional targets of TCF7L2 in hepatocytes. A total of 2119 ChIP peaks were detected, of which 36% were located inside gene boundaries and, overall, a total of 65% of all binding events were within 50 Kb of a gene. De novo motif analysis revealed remarkable conservation of the long and short TCF7L2 consensus binding sites in the rat hepatocytes. Pathway analysis showed that the top two disease categories over-represented in our dataset were “non-insulin dependent diabetes” (155 genes; P = 1.63 x 10-10) and “diabetes mellitus” (245 genes; P = 7.4 x 10-12). Inspection of genes in these categories revealed that TCF7L2 directly binds to multiple genes important in the regulation of glucose metabolism in the liver, including PEPCK, FBP1, IRS1, IRS2, AKT2 ADIPOR1, PDK4 and CPT1A. Our findings suggest a novel mechanism for the regulation of HGP by TCF7L2, and provide a possible explanation for the association of TCF7L2 polymorphisms with the incidence of T2DM.
2011-09-12 | GSE28782 | GEO
Project description:TCF7L2 regulates multiple metabolic pathways in hepatocytes through a transcriptional network involving HNF4M-NM-1 For the identification of Tcf7l2 target genes using a RNA-seq timecourse, and for identifying the binding sites of Tcf7l2 and Hnf4a, Tcf7l2 was silenced in rat H4IIE hepatocytes using siRNA for Tcf7l2 with a scrambled siRNA as control. Treatment times for RNA-seq samples were 3, 6, 9, 12, 15, 18, 48, and 96 hours, and for ChIP-seq samples 15 h. RNA-seq timecourse was performed in duplicate or triplicate, and the ChIP-seq in duplicate for Tcf7l2 and in singlicate for Hnf4a. The H4IIE-specific transcriptome was defined from an independent set of pooled 24 h siRNA treated samples (N=3 for siRNA for Tcf7l2 and N=3 for scrambled siRNA).
2014-11-24 | E-GEOD-53862 | biostudies-arrayexpress
Project description:We used chromatin immunoprecipitation combined with DNA sequencing to identify TCF7L2 localization on thalamic genome. We report that among putative TCF7L2 direct targets are thalamic terminal effector genes.
2020-07-24 | E-MTAB-9384 | biostudies-arrayexpress
Project description:BackgroundGenetic variations of the TCF7L2 gene are associated with the development of Type 2 diabetes (T2D). The associated mutations have demonstrated an adaptive role in some human populations, but no studies have determined the impact of evolutionary forces on genetic diversity in indigenous populations from Mexico. Here, we sequenced and analyzed the variation of the TCF7L2 gene in three Amerindian populations and compared the results with whole-exon-sequencing of Mestizo populations from Sigma and the 1000 Genomes Project to assess the roles of selection and recombination in diversity.ResultsThe diversity in the indigenous populations was biased to intronic regions. Most of the variation was low frequency. Only mutations rs77961654 and rs61724286 were located on exon 15. We did not observe variation in intronic region 4-6 in any of the three indigenous populations. In addition, we identified peaks of selective sweeps in the mestizo samples from the Sigma Project within this region. By replicating the analysis of association with T2D between case-controls from the Sigma Project, we determined that T2D was most highly associated with the rs7903146 risk allele and to a lesser extent with the other six variants. All associated markers were located in intronic region 4-6, and their r(2) values of linkage disequilibrium were significantly higher in the Mexican population than in Africans from the 1000 Genomes Project. We observed reticulations in both the haplotypes network analysis from seven marker associates and the neighborNet tree based on 6061 markers in the TCF7L2 gene identified from all samples of the 1000 Genomes Project. Finally, we identified two recombination hotspots in the upstream region and 3' end of the TCF7L2 gene.ConclusionsThe lack of diversity in intronic region 4-6 in Indigenous populations could be an effect of selective sweeps generated by the selection of neighboring rare variants at T2D-associated mutations. The survivors' variants make the intronic region 4-6 the area of the greatest population differentiation within the TCF7L2 gene. The abundance of selective peak sweeps in the downstream region of the TCF7L2 gene suggests that the TCF7L2 gene is part of a region that is in constant recombination between populations.
| S-EPMC4880969 | biostudies-literature
Project description:The transcription factor TCF7L2 is indispensable for intestinal tissue homeostasis where it transmits mitogenic Wnt/β-Catenin signals in stem and progenitor cells, from which intestinal tumors arise. Yet, TCF7L2 belongs to the most frequently mutated genes in colorectal cancer (CRC), and growth inhibitory functions of TCF7L2 were proposed. This apparent paradox calls for a clarification of the role of TCF7L2 in colorectal carcinogenesis. Here, we investigated TCF7L2 dependence/independence of CRC cells, and the cellular and molecular consequences of TCF7L2 loss-of-function. By genome editing we readily achieved complete TCF7L2 inactivation in several CRC cell lines without loss of viability, showing that CRC cells have widely lost the strict requirement for TCF7L2. Albeit phenotypic changes manifested in a cell-line-specific fashion, TCF7L2-negative cells exhibited morphological changes, enhanced migration and invasion, and augmented collagen adhesion. Additionally, TCF7L2 deficiency led to reduced proliferation, reminiscent of the physiological role of TCF7L2. To provide a molecular framework for the observed phenotypic changes, we performed global transcriptome profiling. This identified gene-regulatory networks in which TCF7L2 positively regulates the proto-oncogene MYC, while repressing the cell cycle inhibitors CDKN2C/CDKN2D. TCF7L2 also suppresses the pro-metastatic transcription factor RUNX2 and several integrin genes, which is consistent with increased motility and collagen adhesion of TCF7L2-deficient cells. Altogether, we conclude that the proliferation-stimulating activity of TCF7L2 persists in CRC cells. Additionally, TCF7L2 acts as invasion suppressor. Despite its negative impact on cell cycle progression, TCF7L2 loss-of-function may thereby increase malignancy, which could explain why TCF7L2 is mutated in a sizeable fraction of colorectal tumors.
2020-03-20 | GSE135328 | GEO
Project description:Arising selective sweeps in Andean high altitude populations
| PRJEB14828 | ENA
Project description:Nicotine contained in tobacco smoke increases blood glucose levels in humans, and the risk of developing diabetes is dramatically increased in habitual smokers. Little is currently known about how nicotine increases blood glucose levels or the relevance of this action to either the persistence of the smoking habit or the pathophysiology of diabetes in smokers. Here, we show that the diabetes-associated gene Tcf7l2 is highly expressed in the medial habenula (mHb), where it regulates the function of local nicotinic acetylcholine receptors. We find that Tcf7l2 mutant (Tcf7l2mut) rats consume far greater quantities of nicotine than wild-type rats. Similarly, CRISPR-mediated cleavage of wild-type Tcf7l2 in the mHb increases nicotine intake in mice. Polysynaptic tracing identified a connection from the mHb to the pancreas, and nicotine-induced activation of the mHb elevates blood glucose. This effect is mimicked by chemogenetic stimulation of the mHb and blocked by Tcf7l2 knockdown in mHb. A history of nicotine consumption elevates circulating levels of the pancreas-derived hormones glucagon and insulin and precipitates diabetes-like dysregulation of blood glucose homeostasis in wild-type rats, whereas Tcf7l2mut rats are resistant to these actions of nicotine. Our findings suggest that Tcf7l2 regulates the stimulatory actions of nicotine on the habenula-pancreas axis, linkings the addictive properties of nicotine to its diabetes-promoting actions.
2019-09-10 | GSE137118 | GEO
Project description:The TCF7L2 transcription factor is linked to a variety of human diseases, including type 2 diabetes and cancer. One mechanism by which TCF7L2 could influence expression of genes involved in diverse diseases is by binding to distinct regulatory regions in different tissues. To test this hypothesis, we performed ChIP-seq for TCF7L2 in 6 human cell lines. We identified 116,000 non-redundant TCF7L2 binding sites, with only 1,864 sites common to the 6 cell lines. Using ChIP-seq, we showed that many genomic regions that are marked by both H3K4me1 and H3K27Ac are also bound by TCF7L2, suggesting that TCF7L2 plays a critical role in enhancer activity. Bioinformatic analysis of the cell type-specific TCF7L2 binding sites revealed enrichment for multiple transcription factors, including HNF4alpha and FOXA2 motifs in HepG2 cells and the GATA3 motif in MCF7 cells. ChIP-seq analysis revealed that TCF7L2 co-localizes with HNF4alpha and FOXA2 in HepG2 cells and with GATA3 in MCF7 cells. Interestingly, in MCF7 cells the TCF7L2 motif is enriched in most TCF7L2 sites but is not enriched in the sites bound by both GATA3 and TCF7L2. This analysis suggested that GATA3 might tether TCF7L2 to the genome at these sites. To test this hypothesis, we depleted GATA3 in MCF7 cells and showed that TCF7L2 binding was lost at a subset of sites. RNA-seq analysis suggested that TCF7L2 represses transcription when tethered to the genome via GATA3. Our studies demonstrate a novel relationship between GATA3 and TCF7L2, and reveal important insights into TCF7L2-mediated gene regulation.
2012-06-05 | GSE38447 | GEO
Project description:The TCF7L2 transcription factor is linked to a variety of human diseases, including type 2 diabetes and cancer. One mechanism by which TCF7L2 could influence expression of genes involved in diverse diseases is by binding to distinct regulatory regions in different tissues. To test this hypothesis, we performed ChIP-seq for TCF7L2 in 6 human cell lines. We identified 116,000 non-redundant TCF7L2 binding sites, with only 1,864 sites common to the 6 cell lines. Using ChIP-seq, we showed that many genomic regions that are marked by both H3K4me1 and H3K27Ac are also bound by TCF7L2, suggesting that TCF7L2 plays a critical role in enhancer activity. Bioinformatic analysis of the cell type-specific TCF7L2 binding sites revealed enrichment for multiple transcription factors, including HNF4alpha and FOXA2 motifs in HepG2 cells and the GATA3 motif in MCF7 cells. ChIP-seq analysis revealed that TCF7L2 co-localizes with HNF4alpha and FOXA2 in HepG2 cells and with GATA3 in MCF7 cells. Interestingly, in MCF7 cells the TCF7L2 motif is enriched in most TCF7L2 sites but is not enriched in the sites bound by both GATA3 and TCF7L2. This analysis suggested that GATA3 might tether TCF7L2 to the genome at these sites. To test this hypothesis, we depleted GATA3 in MCF7 cells and showed that TCF7L2 binding was lost at a subset of sites. RNA-seq analysis suggested that TCF7L2 represses transcription when tethered to the genome via GATA3. Our studies demonstrate a novel relationship between GATA3 and TCF7L2, and reveal important insights into TCF7L2-mediated gene regulation. RNAseq analysis of MCF7 cells transfected with siCONTROL, siTCF7L2 or siGATA3. ChIP-seq analysis of H3K27ac, H3K4me1, H3K27me3, H3K9me3 in MCF7 cells; H3K4me1 and H3K27ac in HCT116 cells.
2012-06-05 | E-GEOD-38447 | biostudies-arrayexpress