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Abstract
O-GlcNAcylation is a dynamic post-translational modification performed by two opposing enzymes: O-GlcNAc transferase and O-GlcNAcase. O-GlcNAcylation is generally believed to act as a metabolic integrator in numerous signalling pathways. The stoichiometry of this modification is tightly controlled throughout all stages of development, with both hypo/hyper O-GlcNAcylation resulting in broad defects. In this Primer, we discuss the role of O-GlcNAcylation in developmental processes from stem cell maintenance and differentiation to cell and tissue morphogenesis.
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Affiliation(s)
- Ignacy Czajewski
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Daan M F van Aalten
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
- Institute of Molecular Precision Medicine, Xiangya Hospital, Central South University, Changsha 410000, China
- Department of Molecular Biology and Genetics, University of Aarhus, Aarhus 8000, Denmark
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Kim MJ, Kim HS, Lee S, Min KY, Choi WS, You JS. Hexosamine Biosynthetic Pathway-Derived O-GlcNAcylation Is Critical for RANKL-Mediated Osteoclast Differentiation. Int J Mol Sci 2021; 22:ijms22168888. [PMID: 34445596 PMCID: PMC8396330 DOI: 10.3390/ijms22168888] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/12/2021] [Accepted: 08/15/2021] [Indexed: 12/23/2022] Open
Abstract
O-linked-N-acetylglucosaminylation (O-GlcNAcylation) performed by O-GlcNAc transferase (OGT) is a nutrient-responsive post-translational modification (PTM) via the hexosamine biosynthetic pathway (HBP). Various transcription factors (TFs) are O-GlcNAcylated, affecting their activities and significantly contributing to cellular processes ranging from survival to cellular differentiation. Given the pleiotropic functions of O-GlcNAc modification, it has been studied in various fields; however, the role of O-GlcNAcylation during osteoclast differentiation remains to be explored. Kinetic transcriptome analysis during receptor activator of nuclear factor-kappaB (NF-κB) ligand (RANKL)-mediated osteoclast differentiation revealed that the nexus of major nutrient metabolism, HBP was critical for this process. We observed that the critical genes related to HBP activation, including Nagk, Gfpt1, and Ogt, were upregulated, while the global O-GlcNAcylation was increased concomitantly during osteoclast differentiation. The O-GlcNAcylation inhibition by the small-molecule inhibitor OSMI-1 reduced osteoclast differentiation in vitro and in vivo by disrupting the translocation of NF-κB p65 and nuclear factor of activated T cells c1 (NFATc1) into the nucleus by controlling their PTM O-GlcNAcylation. Furthermore, OSMI-1 had a synergistic effect with bone target therapy on osteoclastogenesis. Lastly, knocking down Ogt with shRNA (shOgt) mimicked OSMI-1’s effect on osteoclastogenesis. Targeting O-GlcNAcylation during osteoclast differentiation may be a valuable therapeutic approach for osteoclast-activated bone diseases.
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Affiliation(s)
- Myoung Jun Kim
- School of Medicine, Konkuk University, Seoul 05029, Korea; (M.J.K.); (S.L.); (K.Y.M.); (W.S.C.)
| | - Hyuk Soon Kim
- Department of Biomedical Sciences, College of Natural Science, Dong-A University, Busan 49315, Korea;
- Department of Health Sciences, The Graduate School of Dong-A University, Busan 49315, Korea
| | - Sangyong Lee
- School of Medicine, Konkuk University, Seoul 05029, Korea; (M.J.K.); (S.L.); (K.Y.M.); (W.S.C.)
| | - Keun Young Min
- School of Medicine, Konkuk University, Seoul 05029, Korea; (M.J.K.); (S.L.); (K.Y.M.); (W.S.C.)
| | - Wahn Soo Choi
- School of Medicine, Konkuk University, Seoul 05029, Korea; (M.J.K.); (S.L.); (K.Y.M.); (W.S.C.)
- KU Open Innovation Center, Research Institute of Medical Science, Konkuk University, Chungju 27478, Korea
| | - Jueng Soo You
- School of Medicine, Konkuk University, Seoul 05029, Korea; (M.J.K.); (S.L.); (K.Y.M.); (W.S.C.)
- KU Open Innovation Center, Research Institute of Medical Science, Konkuk University, Chungju 27478, Korea
- Correspondence: ; Tel.: +82-2-2049-6235
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Nakajima H, Murakami K. O-GlcNAcylation: Implications in normal and malignant hematopoiesis. Exp Hematol 2021; 101-102:16-24. [PMID: 34302904 DOI: 10.1016/j.exphem.2021.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 07/13/2021] [Accepted: 07/15/2021] [Indexed: 10/20/2022]
Abstract
Posttranslational protein modification through addition of the O-linked β-N-acetyl-D-glucosamine (O-GlcNAc) moiety to serine or threonine residues, termed O-GlcNAcylation, is a highly dynamic process conserved throughout eukaryotes. O-GlcNAcylation is reversibly catalyzed by a single pair of enzymes, O-GlcNAc transferase and O-GlcNAcase, and it acts as a fundamental regulator for a wide variety of biological processes including gene expression, cell cycle regulation, metabolism, stress response, cellular signaling, epigenetics, and proteostasis. O-GlcNAcylation is regulated by various intracellular or extracellular cues such as metabolic status, nutrient availability, and stress. Studies over decades have unveiled the profound biological significance of this unique protein modification in normal physiology and pathologic processes of diverse cell types or tissues. In hematopoiesis, recent studies have indicated the essential and pleiotropic roles of O-GlcNAcylation in differentiation, proliferation, and function of hematopoietic cells including T cells, B cells, myeloid progenitors, and hematopoietic stem and progenitor cells. Moreover, aberrant O-GlcNAcylation is implicated in the development of hematologic malignancies with dysregulated epigenetics, metabolism, and gene transcription. Thus, it is now recognized that O-GlcNAcylation is one of the key regulators of normal and malignant hematopoiesis.
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Affiliation(s)
- Hideaki Nakajima
- Department of Stem Cell and Immune Regulation, Yokohama City University Graduate School of Medicine, Yokohama, Japan.
| | - Koichi Murakami
- Department of Stem Cell and Immune Regulation, Yokohama City University Graduate School of Medicine, Yokohama, Japan
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Sheikh MA, Emerald BS, Ansari SA. Stem cell fate determination through protein O-GlcNAcylation. J Biol Chem 2021; 296:100035. [PMID: 33154167 PMCID: PMC7948975 DOI: 10.1074/jbc.rev120.014915] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 11/05/2020] [Accepted: 11/05/2020] [Indexed: 12/13/2022] Open
Abstract
Embryonic and adult stem cells possess the capability of self-renewal and lineage-specific differentiation. The intricate balance between self-renewal and differentiation is governed by developmental signals and cell-type-specific gene regulatory mechanisms. A perturbed intra/extracellular environment during lineage specification could affect stem cell fate decisions resulting in pathology. Growing evidence demonstrates that metabolic pathways govern epigenetic regulation of gene expression during stem cell fate commitment through the utilization of metabolic intermediates or end products of metabolic pathways as substrates for enzymatic histone/DNA modifications. UDP-GlcNAc is one such metabolite that acts as a substrate for enzymatic mono-glycosylation of various nuclear, cytosolic, and mitochondrial proteins on serine/threonine amino acid residues, a process termed protein O-GlcNAcylation. The levels of GlcNAc inside the cells depend on the nutrient availability, especially glucose. Thus, this metabolic sensor could modulate gene expression through O-GlcNAc modification of histones or other proteins in response to metabolic fluctuations. Herein, we review evidence demonstrating how stem cells couple metabolic inputs to gene regulatory pathways through O-GlcNAc-mediated epigenetic/transcriptional regulatory mechanisms to govern self-renewal and lineage-specific differentiation programs. This review will serve as a primer for researchers seeking to better understand how O-GlcNAc influences stemness and may catalyze the discovery of new stem-cell-based therapeutic approaches.
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Affiliation(s)
- Muhammad Abid Sheikh
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, UAE
| | - Bright Starling Emerald
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, UAE; Zayed Center for Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, UAE
| | - Suraiya Anjum Ansari
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, UAE; Zayed Center for Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, UAE.
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Tazhitdinova R, Timoshenko AV. The Emerging Role of Galectins and O-GlcNAc Homeostasis in Processes of Cellular Differentiation. Cells 2020; 9:cells9081792. [PMID: 32731422 PMCID: PMC7465113 DOI: 10.3390/cells9081792] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/24/2020] [Accepted: 07/24/2020] [Indexed: 02/07/2023] Open
Abstract
Galectins are a family of soluble β-galactoside-binding proteins with diverse glycan-dependent and glycan-independent functions outside and inside the cell. Human cells express twelve out of sixteen recognized mammalian galectin genes and their expression profiles are very different between cell types and tissues. In this review, we summarize the current knowledge on the changes in the expression of individual galectins at mRNA and protein levels in different types of differentiating cells and the effects of recombinant galectins on cellular differentiation. A new model of galectin regulation is proposed considering the change in O-GlcNAc homeostasis between progenitor/stem cells and mature differentiated cells. The recognition of galectins as regulatory factors controlling cell differentiation and self-renewal is essential for developmental and cancer biology to develop innovative strategies for prevention and targeted treatment of proliferative diseases, tissue regeneration, and stem-cell therapy.
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γ-Propoxy-Sulfo-Lichenan Induces In Vitro Cell Differentiation of Human Keratinocytes. Molecules 2019; 24:molecules24030574. [PMID: 30764551 PMCID: PMC6384931 DOI: 10.3390/molecules24030574] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 01/29/2019] [Accepted: 02/05/2019] [Indexed: 11/17/2022] Open
Abstract
Background: As non-cellulosic β-d-glucans are known to exert wound-healing activity by triggering keratinocytes into cellular differentiation, the functionality of a semisynthetic lichenan-based polysaccharide on skin cell physiology was investigated. Methods: γ-Propoxy-sulfo-lichenan (γ-PSL, molecular weight 52 kDa, β-1,3/1,4-p-d-Glucose, degree of substitution 0.7) was prepared from lichenan. Differentiation of primary human keratinocytes was assayed by the protein analysis of differentiation specific markers and by gene expression analysis (qPCR). The gene array gave insight into the cell signaling induced by the polysaccharide. Results: γ-PSL (1 to 100 μg/mL) triggered keratinocytes, in a concentration-dependent manner, into the terminal differentiation, as shown by the increased protein expression of cytokeratin 1 (KRT1). Time-dependent gene expression analysis proved differentiation-inducing effects, indicating strong and fast KRT1 gene expression, while KRT10 expression showed a maximum after 12 to 24 h, followed by downregulation to the basal level. Involucrin gene expression was only changed to a minor extent, which was similar to loricrin and transglutaminase. Gene array indicated the influence of γ-PSL on MAP kinase and TGF-β mediated signaling towards keratinocyte differentiation. Conclusion: The propoxylated lichenan may improve wound healing by topical application to promote the terminal barrier formation of keratinocytes.
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Zhang Z, Parker MP, Graw S, Novikova LV, Fedosyuk H, Fontes JD, Koestler DC, Peterson KR, Slawson C. O-GlcNAc homeostasis contributes to cell fate decisions during hematopoiesis. J Biol Chem 2019; 294:1363-1379. [PMID: 30523150 PMCID: PMC6349094 DOI: 10.1074/jbc.ra118.005993] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 11/29/2018] [Indexed: 11/06/2022] Open
Abstract
The addition of a single β-d-GlcNAc sugar (O-GlcNAc) by O-GlcNAc-transferase (OGT) and O-GlcNAc removal by O-GlcNAcase (OGA) maintain homeostatic O-GlcNAc levels on cellular proteins. Changes in protein O-GlcNAcylation regulate cellular differentiation and cell fate decisions, but how these changes affect erythropoiesis, an essential process in blood cell formation, remains unclear. Here, we investigated the role of O-GlcNAcylation in erythropoiesis by using G1E-ER4 cells, which carry the erythroid-specific transcription factor GATA-binding protein 1 (GATA-1) fused to the estrogen receptor (GATA-1-ER) and therefore undergo erythropoiesis after β-estradiol (E2) addition. We observed that during G1E-ER4 differentiation, overall O-GlcNAc levels decrease, and physical interactions of GATA-1 with both OGT and OGA increase. RNA-Seq-based transcriptome analysis of G1E-ER4 cells differentiated in the presence of the OGA inhibitor Thiamet-G (TMG) revealed changes in expression of 433 GATA-1 target genes. ChIP results indicated that the TMG treatment decreases the occupancy of GATA-1, OGT, and OGA at the GATA-binding site of the lysosomal protein transmembrane 5 (Laptm5) gene promoter. TMG also reduced the expression of genes involved in differentiation of NB4 and HL60 human myeloid leukemia cells, suggesting that O-GlcNAcylation is involved in the regulation of hematopoietic differentiation. Sustained treatment of G1E-ER4 cells with TMG before differentiation reduced hemoglobin-positive cells and increased stem/progenitor cell surface markers. Our results show that alterations in O-GlcNAcylation disrupt transcriptional programs controlling erythropoietic lineage commitment, suggesting a role for O-GlcNAcylation in regulating hematopoietic cell fate.
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Affiliation(s)
- Zhen Zhang
- Departments of Biochemistry and Molecular Biology, Kansas City, Kansas 66160
| | - Matthew P Parker
- Departments of Biochemistry and Molecular Biology, Kansas City, Kansas 66160
| | | | - Lesya V Novikova
- Departments of Biochemistry and Molecular Biology, Kansas City, Kansas 66160
| | - Halyna Fedosyuk
- Departments of Biochemistry and Molecular Biology, Kansas City, Kansas 66160
| | - Joseph D Fontes
- Departments of Biochemistry and Molecular Biology, Kansas City, Kansas 66160; Cancer Center, University of Kansas Medical Center, Kansas City, Kansas 66160
| | - Devin C Koestler
- Biostatistics, Kansas City, Kansas 66160; Cancer Center, University of Kansas Medical Center, Kansas City, Kansas 66160
| | - Kenneth R Peterson
- Departments of Biochemistry and Molecular Biology, Kansas City, Kansas 66160; Cancer Center, University of Kansas Medical Center, Kansas City, Kansas 66160; Anatomy and Cell Biology, Kansas City, Kansas 66160.
| | - Chad Slawson
- Departments of Biochemistry and Molecular Biology, Kansas City, Kansas 66160; Cancer Center, University of Kansas Medical Center, Kansas City, Kansas 66160.
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Lv K, Wang G, Shen C, Zhang X, Yao H. Role and mechanism of the nod-like receptor family pyrin domain-containing 3 inflammasome in oral disease. Arch Oral Biol 2018; 97:1-11. [PMID: 30315987 DOI: 10.1016/j.archoralbio.2018.10.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 10/02/2018] [Accepted: 10/03/2018] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To summarize evidence and data from experimental studies regarding the role and mechanism of the Nod-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome in the pathogenesis of several representative oral diseases. MATERIALS AND METHODS A literature search of PubMed and EBSCO was performed. The literature was searched using a combination of keywords, e.g., NLRP3 inflammasome, inflammation, microorganisms, oral inflammatory diseases, and oral immunological diseases. RESULTS The initiation and activation of the NLRP3 inflammasome are associated with the pathogenesis and progression of several representative oral diseases, including periodontitis, oral lichen planus, dental pulp disease, and oral cavity squamous cell carcinoma. CONCLUSIONS The NLRP3 inflammasome plays a crucial role in the progression of inflammatory and adaptive immune responses. The possible role of the NLRP3 inflammasome in several oral diseases, including not only periodontitis and pulpitis but also mucosal diseases and oral cavity squamous cell carcinoma, may involve the aberrant regulation of inflammatory and immune responses. Understanding the cellular and molecular biology of the NLRP3 inflammasome is necessary because the NLRP3 inflammasome may be a potential therapeutic target for the treatment and prevention of oral inflammatory and immunological diseases.
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Affiliation(s)
- Kejia Lv
- Department of Stomatology, First Affiliated Hospital, College of Medicine, Zhejiang University, China
| | - Guohua Wang
- Department of Stomatology, First Affiliated Hospital, College of Medicine, Zhejiang University, China
| | - Chenlu Shen
- Department of Stomatology, First Affiliated Hospital, College of Medicine, Zhejiang University, China
| | - Xia Zhang
- Department of Stomatology, Affiliated Yinzhou People Hospital, College of Medicine, Ningbo University, China
| | - Hua Yao
- Department of Stomatology, First Affiliated Hospital, College of Medicine, Zhejiang University, China.
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Thi Do T, Phoomak C, Champattanachai V, Silsirivanit A, Chaiyarit P. New evidence of connections between increased O-GlcNAcylation and inflammasome in the oral mucosa of patients with oral lichen planus. Clin Exp Immunol 2018; 192:129-137. [PMID: 29247492 DOI: 10.1111/cei.13091] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Revised: 11/29/2017] [Accepted: 12/05/2017] [Indexed: 12/13/2022] Open
Abstract
Oral lichen planus (OLP) is considered a chronic inflammatory immune-mediated disease of the oral mucosa. Immunopathogenesis of OLP is thought to be associated with cell-mediated immune dysregulation. O-GlcNAcylation is a form of reversible glycosylation. It has been demonstrated that O-GlcNAcylation promoted nuclear factor kappa B (NF-κB) signalling. Activation of NF-кB can induce expression of nucleotide-binding domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome, which is a large intracellular multi-protein complex involving an immune response. Dysregulated expression of the NLRP3 inflammasome was reported to be associated with autoinflammatory diseases. No integrative studies between O-GlcNAcylation and NLRP3 inflammasome in OLP patients have been reported. The present study aimed to determine the immunohistochemical expression of O-GlcNAcylation, NF-κB signalling molecules and NLRP3 inflammasome in oral mucosae of OLP patients. Oral tissue samples were collected from 30 OLP patients and 30 healthy individuals. Immunohistochemical staining and analyses of immunostaining scores were performed to evaluate expression of O-GlcNAcylation, NF-κB signalling molecules and NLRP3 inflammasome. According to observations in this study, significantly higher levels of O-GlcNAcylation, NF-κB signalling molecules and NLRP3 inflammasome were demonstrated in OLP patients compared with control subjects (P < 0·001). Positive correlations among O-GlcNAcylation, NF-κB signalling molecules and NLRP3 inflammasome were also observed in OLP samples (P < 0·01). In conclusion, the present study provides supportive evidence that increased O-GlcNAcylation is associated with increased expression of NLRP3 inflammasome via the NF-κB signalling pathway. These findings provide a new perspective on immunopathogenesis of OLP in relation to autoinflammation.
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Affiliation(s)
- T Thi Do
- Department of Oral Diagnosis, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand.,Research Group of Chronic Inflammatory Oral Diseases and Systemic Diseases Associated with Oral Health, Khon Kaen University, Khon Kaen, Thailand.,Department of Oral Pathology and Periodontology, Faculty of Dentistry, Can Tho University of Medicine and Pharmacy, Can Tho, Vietnam
| | - C Phoomak
- Department of Biochemistry, Research Group for Glycosciences and Glycotechnology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - V Champattanachai
- Laboratory of Biochemistry, Chulabhorn Research Institute, Bangkok, Thailand
| | - A Silsirivanit
- Department of Biochemistry, Research Group for Glycosciences and Glycotechnology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - P Chaiyarit
- Department of Oral Diagnosis, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand.,Research Group of Chronic Inflammatory Oral Diseases and Systemic Diseases Associated with Oral Health, Khon Kaen University, Khon Kaen, Thailand
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Abstract
O-GlcNAcylation - the attachment of O-linked N-acetylglucosamine (O-GlcNAc) moieties to cytoplasmic, nuclear and mitochondrial proteins - is a post-translational modification that regulates fundamental cellular processes in metazoans. A single pair of enzymes - O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) - controls the dynamic cycling of this protein modification in a nutrient- and stress-responsive manner. Recent years have seen remarkable advances in our understanding of O-GlcNAcylation at levels that range from structural and molecular biology to cell signalling and gene regulation to physiology and disease. New mechanisms and functions of O-GlcNAcylation that are emerging from these recent developments enable us to begin constructing a unified conceptual framework through which the significance of this modification in cellular and organismal physiology can be understood.
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Affiliation(s)
- Xiaoyong Yang
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Department of Comparative Medicine, Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | - Kevin Qian
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Department of Comparative Medicine, Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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Protein O-GlcNAcylation: emerging mechanisms and functions. Nat Rev Mol Cell Biol 2017. [PMID: 28488703 DOI: 10.1038/nrm.2017.22,+10.1038/nrn.2017.89,+10.1038/nrn.2017.87] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
O-GlcNAcylation - the attachment of O-linked N-acetylglucosamine (O-GlcNAc) moieties to cytoplasmic, nuclear and mitochondrial proteins - is a post-translational modification that regulates fundamental cellular processes in metazoans. A single pair of enzymes - O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) - controls the dynamic cycling of this protein modification in a nutrient- and stress-responsive manner. Recent years have seen remarkable advances in our understanding of O-GlcNAcylation at levels that range from structural and molecular biology to cell signalling and gene regulation to physiology and disease. New mechanisms and functions of O-GlcNAcylation that are emerging from these recent developments enable us to begin constructing a unified conceptual framework through which the significance of this modification in cellular and organismal physiology can be understood.
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Abstract
O-GlcNAcylation - the attachment of O-linked N-acetylglucosamine (O-GlcNAc) moieties to cytoplasmic, nuclear and mitochondrial proteins - is a post-translational modification that regulates fundamental cellular processes in metazoans. A single pair of enzymes - O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) - controls the dynamic cycling of this protein modification in a nutrient- and stress-responsive manner. Recent years have seen remarkable advances in our understanding of O-GlcNAcylation at levels that range from structural and molecular biology to cell signalling and gene regulation to physiology and disease. New mechanisms and functions of O-GlcNAcylation that are emerging from these recent developments enable us to begin constructing a unified conceptual framework through which the significance of this modification in cellular and organismal physiology can be understood.
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Global increase in O-linked N-acetylglucosamine modification promotes osteoblast differentiation. Exp Cell Res 2015; 338:194-202. [PMID: 26302267 DOI: 10.1016/j.yexcr.2015.08.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Revised: 07/20/2015] [Accepted: 08/20/2015] [Indexed: 01/04/2023]
Abstract
The balance between bone formation and bone resorption is maintained by osteoblasts and osteoclasts, and an imbalance in this bone metabolism leads to osteoporosis. Here, we found that osteoblast differentiation in MC3T3-E1 cells is promoted by the inactivation of O-linked β-N-acetylglucosaminidase (O-GlcNAcase) and suppressed by the inactivation of O-GlcNAc transferase, as indicated by extracellular matrix calcification. The expression of osteogenic genes such as alp, ocn, and bsp during osteoblast differentiation was positively regulated in a O-GlcNAc glycosylation-dependent manner. Because it was confirmed that Ets1 and Runx2 are the two key transcription factors responsible for the expression of these osteogenic genes, their transcriptional activity might therefore be regulated by O-GlcNAc glycosylation. However, osteoclast differentiation of RAW264 cells, as indicated by the expression and activity of tartrate-resistant acid phosphatase, was unaffected by the inactivation of either O-GlcNAcase or O-GlcNAc transferase. Our findings suggest that an approach to manipulate O-GlcNAc glycosylation could be useful for developing the therapeutics for osteoporosis.
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