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Sheikh MA, Alawathugoda TT, Vyas G, Emerald BS, Ansari SA. O-GlcNAc transferase promotes glioblastoma by modulating genes responsible for cell survival, invasion, and inflammation. J Biol Chem 2023; 299:105235. [PMID: 37689115 PMCID: PMC10570119 DOI: 10.1016/j.jbc.2023.105235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 08/23/2023] [Accepted: 08/29/2023] [Indexed: 09/11/2023] Open
Abstract
Metabolic reprogramming has emerged as one of the key hallmarks of cancer cells. Various metabolic pathways are dysregulated in cancers, including the hexosamine biosynthesis pathway. Protein O-GlcNAcylation is catalyzed by the enzyme O-GlcNAc transferase (OGT), an effector of hexosamine biosynthesis pathway that is found to be upregulated in most cancers. Posttranslational O-GlcNAcylation of various signaling and transcriptional regulators could promote cancer cell maintenance and progression by regulating gene expression, as gene-specific transcription factors and chromatin regulators are among the most highly O-GlcNAcylated proteins. Here, we investigated the role of OGT in glioblastoma. We demonstrate that 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 show that genes downregulated due to OGT reduction are also known to be transcriptionally regulated by transcriptional initiation/elongation cofactor BRD4. We found BRD4 to be O-GlcNAcylated in glioblastoma cells; however, OGT knockdown/inhibition neither changed its expression nor its chromatin association on promoters. Intriguingly, we observed OGT knockdown led to reduced Pol II-Ser2P chromatin association on target genes without affecting other transcription initiation/elongation factors. Finally, we found that chemical inhibition of BRD4 potentiated the effects of OGT inhibition in reducing glioblastoma cell proliferation, invasion, and migration. We propose BRD4 and OGT act independently in the transcriptional regulation of a common set of genes and that combined inhibition of OGT and BRD4 could be utilized therapeutically for more efficient glioblastoma cell targeting than targeting of either protein alone.
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Affiliation(s)
- Muhammad Abid Sheikh
- Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates
| | - Thilina T Alawathugoda
- Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates
| | - Garima Vyas
- Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates
| | - Bright Starling Emerald
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates; Zayed Center for Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates; Precision Medicine Research Institute Abu Dhabi (PMRIAD), United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates
| | - Suraiya A Ansari
- Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates; Zayed Center for Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates; Precision Medicine Research Institute Abu Dhabi (PMRIAD), United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates.
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Varghese DS, Alawathugoda TT, Sheikh MA, Challagandla AK, Emerald BS, Ansari SA. Developmental modeling of hepatogenesis using obese iPSCs-hepatocyte differentiation uncovers pathological features. Cell Death Dis 2022; 13:670. [PMID: 35915082 PMCID: PMC9343434 DOI: 10.1038/s41419-022-05125-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 07/20/2022] [Accepted: 07/21/2022] [Indexed: 01/21/2023]
Abstract
Obesity is a multigene disorder. However, in addition to genetic factors, environmental determinants also participate in developing obesity and related pathologies. Thus, obesity could be best described as a combination of genetic and environmental perturbations often having its origin during the early developmental period. Environmental factors such as energy-dense food and sedentary lifestyle are known to be associated with obesogenicity. However, the combinatorial effects of gene-environment interactions are not well understood. Understanding the role of multiple genetic variations leading to subtle gene expression changes is not practically possible in monogenic or high-fat-fed animal models of obesity. In contrast, human induced pluripotent stem cells (hiPSCs) from individuals with familial obesity or an obesogenic genotype could serve as a good model system. Herein, we have used hiPSCs generated from normal and genetically obese subjects and differentiated them into hepatocytes in cell culture. We show that hepatocytes from obese iPSCs store more lipids and show increased cell death than normal iPSCs. Whole transcriptome analyses in both normal and obese iPSCs treated with palmitate compared to control revealed LXR-RXR and hepatic fibrosis pathways were enriched among other pathways in obese iPSCs compared to normal iPSCs. Among other genes, increased CD36 and CAV1 expression and decreased expression of CES1 in obese iPSCs could have been responsible for excess lipid accumulation, resulting in differential expression of genes associated with hepatic fibrosis, a key feature of non-alcoholic fatty liver disease (NAFLD). Our results demonstrate that iPSCs derived from genetically obese subjects could serve as an excellent model to understand the effects of this multigene disorder on organ development and may uncover pathologies of NAFLD, which is highly associated with obesity.
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Affiliation(s)
- Divya Saro Varghese
- grid.43519.3a0000 0001 2193 6666Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates
| | - Thilina T. Alawathugoda
- grid.43519.3a0000 0001 2193 6666Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates
| | - Muhammad Abid Sheikh
- grid.43519.3a0000 0001 2193 6666Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates
| | - Anil Kumar Challagandla
- grid.43519.3a0000 0001 2193 6666Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates
| | - Bright Starling Emerald
- grid.43519.3a0000 0001 2193 6666Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates ,grid.43519.3a0000 0001 2193 6666Zayed Center for Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi UAE
| | - Suraiya A. Ansari
- grid.43519.3a0000 0001 2193 6666Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates ,grid.43519.3a0000 0001 2193 6666Zayed Center for Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi UAE
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Parween S, Alawathugoda TT, Prabakaran AD, Dheen ST, Morse RH, Emerald BS, Ansari SA. Nutrient sensitive protein O-GlcNAcylation modulates the transcriptome through epigenetic mechanisms during embryonic neurogenesis. Life Sci Alliance 2022; 5:5/8/e202201385. [PMID: 35470239 PMCID: PMC9039347 DOI: 10.26508/lsa.202201385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 04/11/2022] [Accepted: 04/11/2022] [Indexed: 01/02/2023] Open
Abstract
Protein O-GlcNAcylation is a dynamic, nutrient-sensitive mono-glycosylation deposited on numerous nucleo-cytoplasmic and mitochondrial proteins, including transcription factors, epigenetic regulators, and histones. However, the role of protein O-GlcNAcylation on epigenome regulation in response to nutrient perturbations during development is not well understood. Herein we recapitulated early human embryonic neurogenesis in cell culture and found that pharmacological up-regulation of O-GlcNAc levels during human embryonic stem cells' neuronal differentiation leads to up-regulation of key neurogenic transcription factor genes. This transcriptional de-repression is associated with reduced H3K27me3 and increased H3K4me3 levels on the promoters of these genes, perturbing promoter bivalency possibly through increased EZH2-Thr311 phosphorylation. Elevated O-GlcNAc levels also lead to increased Pol II-Ser5 phosphorylation and affect H2BS112O-GlcNAc and H2BK120Ub1 on promoters. Using an in vivo rat model of maternal hyperglycemia, we show similarly elevated O-GlcNAc levels and epigenetic dysregulations in the developing embryo brains because of hyperglycemia, whereas pharmacological inhibition of O-GlcNAc transferase (OGT) restored these molecular changes. Together, our results demonstrate O-GlcNAc mediated sensitivity of chromatin to nutrient status, and indicate how metabolic perturbations could affect gene expression during neurodevelopment.
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Affiliation(s)
- Shama Parween
- Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Thilina T Alawathugoda
- Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Ashok D Prabakaran
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - S Thameem Dheen
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Randall H Morse
- New York State Department of Health, Wadsworth Center, Albany, NY, USA
| | - Bright Starling Emerald
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates.,Zayed Center for Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Suraiya A Ansari
- Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates .,Zayed Center for Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
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