Effect of O-GlcNAc transferase deficiency on intestinal epithelial cells in mice
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE100473 | GEO | 2017/06/27
SECONDARY ACCESSION(S): PRJNA391919
REPOSITORIES: GEO
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Project description:Dysfunctional mitochondria and generation of reactive oxygen species (ROS) promote chronic diseases, which have spurred interest in the molecular mechanisms underlying these conditions. Previously, we have demonstrated that disruption of post-translational modification of proteins with β-linked N-acetylglucosamine (O- glcnAcylation) via overexpression of the O-glcnAc–regulating enzymes O- glcnAc transferase (OGT) or O- glcnAcase (OGA) impairs mitochondrial function. Here, we report that sustained alterations in O- glcnAcylation either by pharmacological or genetic manipulation also alters metabolic function. Sustained O-glcnAc elevation in SH-SY5Y neuroblastoma cells increased OGA expression and reduced cellular respiration and ROS generation. Cells with elevated O-glcnAc levels had elongated mitochondria and increased mitochondrial membrane potential, and RNA-Seq in SH-SY5Y cells indicated transcriptome reprogramming and down regulation of the NRF2-mediated antioxidant response. Sustained O-glcnAcylation in mice brain and liver validated the metabolic phenotypes observed in the cells, and OGT knockdown in the liver elevated ROS levels, impaired respiration, and increased the NRF2 antioxidant response. Moreover, elevated O-glcnAc levels promoted weight loss and lowered respiration in mice and skewed the mice toward carbohydrate-dependent metabolism as determined by indirect calorimetry. In summary, sustained elevation in O-glcnAcylation coupled with increased OGA expression reprograms energy metabolism, a finding that has potential implications for the etiology, development, and management of metabolic diseases.
2017-07-20 | GSE101642 | GEO
Project description:We report that cellular O-GlcNAcylation levels decline along the course of megakaryocyte (MK) differentiation from human-derived hematopoietic stem and progenitor cells (HSPCs) and that inhibition of O-GlcNAc transferase (OGT), of which catalyzes O-GlcNAcylation, prolongedly decreases O-GlcNAcylation and induces megakaryopoiesis and thrombopoiesis. To gain the better insight into the potential mechanisms underlying platelet regulation by O-GlcNAcylation ,we compared the genome-wide transcription profiles of megakaryblastic MEG-01 cells with decreased O-GlcNAcylation (OGTi) and its control counterpart using RNA sequencing. Gene ontology and enrichment analysis of differentially expressed genes suggest that platelet formation might be regulated through the perturbation in cell adhesion molecules, i.e. integrin-a4 and b7, downstream of O-GlcNAc/c-Myc axis.
2020-08-06 | GSE150880 | GEO
Project description:O-Linked N-acetylglucosamine (O-GlcNAc) is a monosaccharide that plays an essential role in cellular signaling throughout the nucleocytoplasmic proteome of eukaryotic cells. Yet, the study of post-translational modifications like O-GlcNAc has been limited by the lack of strategies to induce O-GlcNAcylation of a target protein in cells. Here, we report a generalizable genetic strategy to induce O-GlcNAc to specific target proteins in cells using a nanobody as a proximity-directing agent fused to O-GlcNAc transferase (OGT). Fusion of a nanobody that recognizes GFP (nGFP) or a nanobody that recognizes the four-amino acid sequence EPEA (nEPEA) to OGT(4), a truncated form of OGT, yielded a nanobody-OGT(4) construct that selectively delivered O-GlcNAc to the target protein (e.g., JunB, cJun, Nup62) and reduced alteration of global O-GlcNAc levels in the cell. Chemical proteomics confirmed the selective increase in O-GlcNAc to the target protein by nanobody-OGT(4). Glycoproteomics on the target protein revealed similar glycosite selectivity between nanobody-OGT(4) or global elevation of O-GlcNAc. Finally, we demonstrate the ability to selectively target endogenous ⍺-synuclein for glycosylation in HEK293T cells. Thus, the use of nanobodies to redirect OGT substrate selection is a versatile strategy to induce glycosylation to desired target proteins in cells that will facilitate discovery of O-GlcNAc functions and provide a mechanism to engineer O-GlcNAc signaling. The proximity-directed OGT approach for protein-selective O-GlcNAcylation is readily translated to additional protein targets and nanobodies, and may constitute a generalizable strategy to control post-translational modifications in cells.
2021-09-08 | PXD016041 | Pride
Project description:O-GlcNAcylation is a reversible post-translational modification controlled by the activity of two enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). In the liver, O-GlcNAcylation has emerged as an important regulatory mechanism underlying normal liver physiology and metabolic disease.To address whether OGT acts as a critical hepatic nutritional node, mice with a constitutive hepatocyte-specific deletion of OGT (OGTLKO) were generated.Analyses of 4-week-old OGTLKO mice revealed significant oxidative and endoplasmic reticulum stress, and DNA damage, together with inflammation and fibrosis, in the liver. Susceptibility to oxidative and endoplasmic reticulum stress- induced apoptosis was also elevated in OGTLKO hepatocytes. Although OGT expression was partially recovered in the liver of 8- week-old OGTLKO mice, hepatic injury and fibrosis were not rescued but rather worsened with time. Interestingly, weaning of OGTLKO mice on a ketogenic diet (low carbohydrate, high fat) fully prevented the hepatic alterations induced by OGT deletion, indicating that reduced carbohydrate intake protects an OGT-deficient liver. These findings pinpoint OGT as a key mediator of hepatocyte homeostasis and survival upon carbohydrate intake and validate OGTLKO mice as a valuable model for assessing therapeutical approaches of advanced liver fibrosis.
2024-03-12 | GSE261136 | GEO
Project description:Abstract: The essential mammalian enzyme O-GlcNAc Transferase (OGT) is uniquely responsible for transferring N-acetylglucosamine to over a thousand nuclear and cytoplasmic proteins, yet there is no known consensus sequence and it remains unclear how OGT recognizes its substrates. To address this question, we have developed a protein microarray assay that chemoenzymatically labels de novo sites of glycosylation with biotin, allowing us to simultaneously as-sess OGT activity across >6000 human proteins. We used this assay to examine the contribution of a conserved asparagine ladder within the lumen of OGT’s superhelical tetratri-copeptide repeat (TPR) domain to substrate selection. When these residues were mutated, OGT retained full activity against short peptides, but showed low to no activity against most of the OGT substrates on the microarray. O-GlcNAcylation of protein substrates in cell extracts was also greatly attenuated. We conclude that OGT recognizes a majority of its substrates by binding them to the asparagine ladder in the TPR lumen proximal to the catalytic domain. This series contains microarray data both comparing the new chemoenzymatic method to antibody-based detection as well as comparing arrays treated with wild-type OGT, 5N5A mutant OGT, or controls not treated with enzyme. Note: all CTD-stained arrays or control array raw files are contained in GSE107911_RAW.tar
2018-02-26 | GSE107911 | GEO
Project description:Discriminating pathogenic bacteria from energy-harvesting commensals is key to host immunity. Using mutants defective in the enzymes of O-linked N-acetylglucosamine (O-GlcNAc) cycling, we examined the role of this nutrient-sensing pathway in the Caenorhabidits elegans innate immune response. Using whole genome transcriptional profiling, O-GlcNAc cycling mutants exhibited deregulation of unique stress- and immune-responsive genes as well as genes shared with the p38 MAPK/PMK-1 pathway. Moreover, genetic analysis showed that deletion of O-GlcNAc transferase (ogt-1) yielded animals hypersensitive to the human pathogen S. aureus but not to P. aeruginosa. Genetic interaction studies further revealed that nutrient-responsive OGT-1 acts through the conserved ß-catenin (BAR-1) pathway and in concert with p38 MAPK/PMK-1 to modulate the immune response to S. aureus. The participation of the nutrient sensor O-GlcNAc transferase in an immunity module conserved from C. elegans to humans reveals an unexplored nexus between nutrient availability and a pathogen-specific immune response. In C. elegans, three mutant strains(genotypes used: N2 (wild-type), ogt-1 (ok1474), oga-1 (ok1207), and pmk-1 (km25)) were treated with the human pathogen S. aureus (SA) or P. aeruginosa(PA) and OP50 (E. coli control) with three biological replications.
2015-05-01 | E-GEOD-53732 | biostudies-arrayexpress
Project description:Every year, about 18 million babies are born from mothers with gestational diabetes mellitus (GDM). While diabetic symptoms usually resolve after delivery, lasting complications can occur for both mother and child, including fetal overgrowth, type 2 diabetes (T2D), cardiovascular diseases, and obesity. The rapid progression of GDM is unique to pregnancies, and likely arises from placental dysfunction. Indeed, stress, nutrition and fetal gender are thought to trigger changes in placental endocrine function, including metabolic hormones and inflammatory cytokines, potentially causing GDM. Nutrient-sensing O-GlcNAcylation and its enzyme O-GlcNAc Transferase (OGT, X-linked) has been previously identified as a placental biomarker of maternal stress particularly deleterious for male offspring. Thus, we wondered whether O-GlcNAcylation participate in GDM development in a sex-dependent manner. After demonstrating that OGT is largely downregulated in male GDM compared to healthy placentas, we knocked down OGT in male trophoblastic cells. We observed changes in placental hormones, cytokines and nutrient-sensing pathways, correlating with previously demonstrated disruption in GDM placentas. Altogether, this study demonstrates that OGT and O-GlcNAcylation are partly responsible for changes observed in GDM placenta and might be the cause of sexual dimorphism observed in this pathology.
2022-04-21 | GSE200983 | GEO
Project description:Metabolic reprogramming has emerged as one of the key hallmarks of cancer cells. Various metabolic pathways are dysregulated in cancers including hexosamine biosynthesis pathway (HBP). Protein O-GlcNAcylation catalyzed by O-GlcNAc transferase (OGT), the effector of HBP is found to be upregulated in most cancers. Post-translational O-GlcNAcylation of various signaling and transcriptional regulators could promote cancer cell maintenance and progression through protein stability and gene expression regulation. Indeed, among majority of O-GlcNAcylated proteins are gene specific transcription factors and chromatin regulators. Therefore, investigating the role of OGT in particular types of cancers is crucial. Here, we have investigated the role of OGT in glioblastoma. OGT knockdown and chemical inhibition led to reduced glioblastoma cell proliferation and downregulation of many genes known to play key roles in glioblastoma cell proliferation, migration and invasion.We knocked down OGT and OGA enzyme expression by shRNAs followed by RNA sequencing was carried.
2023-10-23 | GSE234473 | GEO
Project description:Abstract: O-GlcNAc is an abundant post-translational modification found on nuclear and cytoplasmic proteins in all metazoans. This modification regulates a wide variety of cellular processes, and elevated O-GlcNAc levels have been implicated in cancer progression. A single essential enzyme, O-GlcNAc transferase (OGT), is responsible for all nucleocytoplasmic O-GlcNAcylation. Understanding how this enzyme chooses its substrates is critical for understanding, and potentially manipulating, its functions. Here we use protein microarray technology and proteome-wide glycosylation profiling to show that conserved aspartate residues in the tetratricopeptide repeat (TPR) lumen of OGT drive substrate selection. Changing these residues to alanines alters substrate selectivity and unexpectedly increases rates of protein glycosylation. Our findings support a model where sites of glycosylation for many OGT substrates are determined by TPR domain contacts to substrate side chains five to fifteen residues C-terminal to the glycosite. In addition to guiding design of inhibitors that target OGT's TPR domain, this information will inform efforts to engineer substrates to explore biological functions.
2019-07-24 | GSE132205 | GEO
Project description:O-GlcNAc is a dynamic post-translational modification on thousands of intracellular proteins, it regulates protein functions and is involved in many metabolic diseases. Using a dual-specificity aptamer, we targeted the O-GlcNAc transferase (OGT) to endogenous β-catenin and specifically increased O-GlcNAcylation of β-catenin. To study how O-GlcNAcylation of β-catenin regulates the transcriptome, we performed RNA sequencing on HEK293T cells expressing individual (Ctrl.) or dual-specificity aptamers. We found that O-GlcNAcylation of β-catenin shifts the transcriptome in a Wnt-dependent manner: it repressed the expression of about 100 genes in the absence of Wnt, while it activated the expression of these genes when Wnt signaling was turned on. This dataset is from the control experiment in which all samples were treated with the OGT inhibitor Ac5S.
2022-11-01 | GSE189622 | GEO