O-linked β-N-acetylglucosamine transferase plays an essential role in heart development through regulating angiopoietin-1
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE146962 | GEO | 2020/03/14
REPOSITORIES: GEO
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Project description:O-linked N-acetylglucosamine (GlcNAc) transferase (OGT) is the only enzyme catalyzing O-GlcNAcylation. Although it has been shown that OGT plays an essential role in maintaining postnatal heart function, its role in heart development remains unknown. Here we showed that loss of OGT in early fetal cardiomyocytes led to multiple heart developmental defects including hypertrabeculation, biventricular dilation, atrial septal defects, ventricular septal defects, and defects in coronary vessel development. In addition, RNA sequencing revealed that Angiopoietin-1, required within cardiomyocytes for both myocardial and coronary vessel development, was dramatically downregulated in cardiomyocyte-specific OGT knockout mouse hearts. In conclusion, our data demonstrated that OGT plays an essential role in regulating heart development through activating expression of cardiomyocyte Angiopoietin-1.
| S-EPMC7182263 | biostudies-literature
Project description:O-linked N-acetylglucosamine (O-GlcNAc) transferase (OGT) catalyzes post-translational modification of target proteins by introducing O-GlcNAc moiety on serine or threonine residues. OGT critically regulates various cellular functions in many cell types. However, its roles in hematopoietic stem and progenitor cells (HSPCs) are totally unknown. Here we report critical roles of OGT in homeostasis of HSPCs. Ogt is highly expressed in HSPCs and its disruption led to their rapid loss with increased reactive oxygen species and apoptosis. In particular, Ogt-deficient HSCs lost quiescence and showed severe defects in self-renewal and long-term repopulation capacities. Interestingly, Ogt-deficient HSCs accumulated defective mitochondria due to impaired mitophagy with decreased key mitophagy regulators, Pink1 and Bnip3, through dysregulation of host cell factor 1 (HCF1)-H3K4me3 pathway, and overexpression of Pink1 rescued impaired mitophagy and numbers of Ogt-deficient HSCs. In summary, our results revealed that OGT plays an essential role in HSC maintenance by assuring mitochondrial quality through mitophagy.
2020-12-09 | GSE116433 | GEO
Project description:O-linked β-N-acetylglucosamine transferase plays an essential role in heart development through regulating angiopoietin-1
| PRJNA612518 | ENA
Project description:The failing heart is subject to elevated metabolic demands, adverse remodeling, chronic apoptosis, and ventricular dysfunction. The interplay among such pathologic changes is largely unknown. Several laboratories have identified a unique posttranslational modification that may have significant effects on cardiovascular function. The O-linked β-N-acetylglucosamine (O-GlcNAc) posttranslational modification (O-GlcNAcylation) integrates glucose metabolism with intracellular protein activity and localization. Because O-GlcNAc is derived from glucose, we hypothesized that altered O-GlcNAcylation would occur during heart failure and figure prominently in its pathophysiology. After 5 d of coronary ligation in WT mice, cardiac O-GlcNAc transferase (OGT; which adds O-GlcNAc to proteins) and levels of O-GlcNAcylation were significantly (P < 0.05) elevated in the surviving remote myocardium. We used inducible, cardiac myocyte-specific Cre recombinase transgenic mice crossed with loxP-flanked OGT mice to genetically delete cardiomyocyte OGT (cmOGT KO) and ascertain its role in the failing heart. After tamoxifen induction, cardiac O-GlcNAcylation of proteins and OGT levels were significantly reduced compared with WT, but not in other tissues. WT and cardiomyocyte OGT KO mice underwent nonreperfused coronary ligation and were followed for 4 wk. Although OGT deletion caused no functional change in sham-operated mice, OGT deletion in infarcted mice significantly exacerbated cardiac dysfunction compared with WT. These data provide keen insights into the pathophysiology of the failing heart and illuminate a previously unrecognized point of integration between metabolism and cardiac function in the failing heart.
| S-EPMC2955091 | biostudies-literature
Project description:O-Linked beta-N-acetylglucosamine (O-GlcNAc) transferase (OGT) catalyzes the addition of O-linked beta-N-acetylglucosamine (O-GlcNAc) onto serine and threonine residues in response to stimuli or stress analogous to phosphorylation by Ser/Thr-kinases. Like protein phosphatases, OGT appears to be targeted to myriad specific substrates by transiently interacting with specific targeting subunits. Here, we show that OGT is activated by insulin signaling. Insulin treatment of 3T3-L1 adipocytes stimulates both tyrosine phosphorylation and catalytic activity of OGT. A subset of OGT co-immunoprecipitates with the insulin receptor. Insulin stimulates purified insulin receptor to phosphorylate OGT in vitro. OGT is a competitive substrate with reduced and carboxyamidomethylated lysozyme (RCAM-lysozyme), a well characterized insulin receptor substrate. Insulin stimulation of 3T3-L1 adipocytes results in a partial translocation of OGT from the nucleus to the cytoplasm. The insulin activation of OGT results in increased O-GlcNAc modification of OGT and other proteins including, signal transducer and activator of transcription 3 (STAT3). We conclude that insulin stimulates the tyrosine phosphorylation and activity of OGT.
| S-EPMC2490780 | biostudies-literature
Project description:Most species of filamentous cyanobacteria are capable of gliding motility, likely via a conserved type IV pilus-like system that may also secrete a motility-associated polysaccharide. In a subset of these organisms, motility is achieved only after the transient differentiation of hormogonia, which are specialized filaments that enter a nongrowth state dedicated to motility. Despite the fundamental importance of hormogonia to the life cycles of many filamentous cyanobacteria, the molecular regulation of hormogonium development is largely undefined. To systematically identify genes essential for hormogonium development and motility in the model heterocyst-forming filamentous cyanobacterium Nostoc punctiforme, a forward genetic screen was employed. The first gene identified using this screen, designated ogtA, encodes a putative O-linked β-N-acetylglucosamine transferase (OGT). The deletion of ogtA abolished motility, while ectopic expression of ogtA induced hormogonium development even under hormogonium-repressing conditions. Transcription of ogtA is rapidly upregulated (1 h) following hormogonium induction, and an OgtA-GFPuv fusion protein localized to the cytoplasm. In developing hormogonia, accumulation of PilA but not HmpD is dependent on ogtA Reverse transcription-quantitative PCR (RT-qPCR) analysis indicated equivalent levels of pilA transcript in the wild-type and ΔogtA mutant strains, while a reporter construct consisting of the intergenic region in the 5' direction of pilA fused to gfp produced lower levels of fluorescence in the ΔogtA mutant strain than in the wild type. The production of hormogonium polysaccharide in the ΔogtA mutant strain is reduced compared to that in the wild type but comparable to that in a pilA deletion strain. Collectively, these results imply that O-GlcNAc protein modification regulates the accumulation of PilA via a posttranscriptional mechanism in developing hormogonia.IMPORTANCE Filamentous cyanobacteria are among the most developmentally complex prokaryotes. Species such as Nostoc punctiforme develop an array of cell types, including nitrogen-fixing heterocysts, spore-like akinetes, and motile hormogonia, that function in dispersal as well as the establishment of nitrogen-fixing symbioses with plants and fungi. These symbioses are major contributors to global nitrogen fixation. Despite the fundamental importance of hormogonia to the life cycle of filamentous cyanobacteria and the establishment of symbioses, the molecular regulation of hormogonium development is largely undefined. We employed a genetic screen to identify genes essential for hormogonium development and motility in Nostoc punctiforme The first gene identified using this screen encodes a eukaryotic-like O-linked β-N-acetylglucosamine transferase that is required for accumulation of PilA in hormogonia.
| S-EPMC5388816 | biostudies-literature
Project description:BackgroundOverriding the differentiation blockage in acute myeloid leukemia (AML) is the most successful mode-of-action in leukemia therapy - now curing the vast majority of patients with acute promyelocytic leukemia (APL) using all-trans retinoic acid (ATRA)-based regimens. Similar approaches in other leukemia subtypes, such as IDH1/2-mutated AML, are under active investigation. We herein present successful release of the differentiation blockage upon treatment with the natural (-)-Δ9-Tetrahydrocannabinol isomer dronabinol in vitro and in vivo.MethodsCellular maturation and differentiation were followed in two patients employing whole genome methylation profiling, proteome analyses, NGS deep sequencing and multispectral imaging flow cytometry. For functional studies lentiviral OGT knock-down in vitro and ex vivo cell models were created to evaluate proliferative, apoptotic and differentiating effects of OGT in acute leukemia.FindingsIn here, we provide molecular evidence that dronbinol is capable to override the differentiation blockage of acute leukemia blasts at the state of the leukemia-initiating clone. We further identify the O-linked β-N-acetyl glucosamine (O-GlcNAc) transferase (OGT) to be crucial in this process. OGT is a master regulator enzyme adding O-GlcNAc to serine or threonine residues in a multitude of target proteins. Aberrant O-GlcNAc modification is implicated in pathologies of metabolic, neurodegenerative and autoimme diseases as well as cancers. We provide evidence that dronabinol induces transcription of OGT via epigenetic hypomethylation of the transcription start site (TSS). A lentiviral OGT-knock out approach proves the central role of OGT exerting antileukemic efficacy via a dual-mechanism of action: High concentrations of dronabinol result in induction of apoptosis, whereas lower concentrations drive cellular maturation. Most intriguingly, overriding of the differentiation blockage of acute leukemia blasts is validated in vivo following two patients treated with dronabinol.InterpretationIn conclusion, we provide evidence for overcoming the differentiation blockage in acute leukemia in subentities beyond promyelocytic and IDH1/2-mutated leukemia and thereby identify O-GlcNAcylation as a novel (drugable) field for future leukemia research.FundingUnrestricted grant support by the IZKF Program of the Medical Faculty Tübingen (MMS) and Brigitte Schlieben-Lange Program as well as the Margarete von Wrangell Program of the Ministry of Science, Research and the Arts, Baden-Württemberg, Germany (KKS) and Athene Program of the excellence initiative University of Tübingen (KKS).
| S-EPMC7139116 | biostudies-literature
Project description:Cancer cells universally increase glucose and glutamine consumption, leading to the altered metabolic state known as the Warburg effect; one metabolic pathway, highly dependent on glucose and glutamine, is the hexosamine biosynthetic pathway. Increased flux through the hexosamine biosynthetic pathway leads to increases in the post-translational addition of O-linked β-N-acetylglucosamine (O-GlcNAc) to various nuclear and cytosolic proteins. A number of these target proteins are implicated in cancer, and recently, O-GlcNAcylation was shown to play a role in breast cancer; however, O-GlcNAcylation in other cancers remains poorly defined. Here, we show that O-GlcNAc transferase (OGT) is overexpressed in prostate cancer compared with normal prostate epithelium and that OGT protein and O-GlcNAc levels are elevated in prostate carcinoma cell lines. Reducing O-GlcNAcylation in PC3-ML cells was associated with reduced expression of matrix metalloproteinase (MMP)-2, MMP-9, and VEGF, resulting in inhibition of invasion and angiogenesis. OGT-mediated regulation of invasion and angiogenesis was dependent upon regulation of the oncogenic transcription factor FoxM1, a key regulator of invasion and angiogenesis, as reducing OGT expression led to increased FoxM1 protein degradation. Conversely, overexpression of a degradation-resistant FoxM1 mutant abrogated OGT RNAi-mediated effects on invasion, MMP levels, angiogenesis, and VEGF expression. Using a mouse model of metastasis, we found that reduction of OGT expression blocked bone metastasis. Altogether, these data suggest that as prostate cancer cells alter glucose and glutamine levels, O-GlcNAc modifications and OGT levels become elevated and are required for regulation of malignant properties, implicating OGT as a novel therapeutic target in the treatment of cancer.
| S-EPMC3322861 | biostudies-literature
Project description:The O-linked β-N-acetylglucosamine modification is a core signalling mechanism, with erroneous patterns leading to cancer and neurodegeneration. Although thousands of proteins are subject to this modification, only a single essential glycosyltransferase catalyses its installation, the O-GlcNAc transferase, OGT. Previous studies have provided truncated structures of OGT through X-ray crystallography, but the full-length protein has never been observed. Here, we report a 5.3 Å cryo-EM model of OGT. We show OGT is a dimer, providing a structural basis for how some X-linked intellectual disability mutations at the interface may contribute to disease. We observe that the catalytic section of OGT abuts a 13.5 tetratricopeptide repeat unit region and find the relative positioning of these sections deviate from the previously proposed, X-ray crystallography-based model. We also note that OGT exhibits considerable heterogeneity in tetratricopeptide repeat units N-terminal to the dimer interface with repercussions for how OGT binds protein ligands and partners.
| S-EPMC8586251 | biostudies-literature
Project description:Hypocalcemia, associated with Calcium neurotoxicity, has been reported to induce nerve dysfunction, which is a significant problem of renal failure. This study identifies a molecular mechanism of the O-linked N-acetylglucosamine transferase (OGT)-mediated enhancer of zeste homolog 2 (EZH2)/krüppel-like factor 2 (KLF2)/chemokine (C-X-C motif) ligand 1 (CXCL1) axis underlying the hypercalcemia-induced nerve injury in renal failure. Bioinformatics analyses were used to screen out the key factors in hypercalcemia-induced nerve injury in renal failure. Chronic kidney disease (CKD) was induced by an adenine diet in mice, followed by injection of adenovirus vector carrying short hairpin RNA targeting OGT, followed by behavioral tests and collection of the cerebral cortex for primary neurons. Calcium level in neurons was measured by Fluo-4-am and Perkin Elmer+ Operetta. Neuronal apoptosis and viability were detected by flow cytometry and the MTS method. The binding of EZH2 to KLF2 promoter was verified by chromatin immunoprecipitation assay. The concentration of Ca2+ in brain tissues of CKD model mice was increased, and nerve functions were obviously damaged. High expression of OGT occurred in kidney tissue of CKD model mice. Silencing OGT reduced the hypercalcemia-induced toxicity of neurons by inhibiting the expression of EZH2, which elevated the expression of CXCL1 in primary neurons by diminishing KLF2. Silencing OGT attenuated hypercalcemia-induced neurotoxicity by regulating the EZH2/KLF2/CXCL1 axis. In vivo experiments further confirmed that silencing OGT could reduce hypercalcemia-induced nerve injury in CKD mice. Taken together, silencing OGT downregulates EZH2, which increases the expression of KLF2 and then decreases the expression of CXCL1, thus alleviating hypercalcemia-induced nerve injury in renal failure.
| S-EPMC8405781 | biostudies-literature