1
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Walker EM, Pearson GL, Lawlor N, Stendahl AM, Lietzke A, Sidarala V, Zhu J, Stromer T, Reck EC, Li J, Levi-D’Ancona E, Pasmooij MB, Hubers DL, Renberg A, Mohamed K, Parekh VS, Zhang IX, Thompson B, Zhang D, Ware SA, Haataja L, Qi N, Parker SCJ, Arvan P, Yin L, Kaufman BA, Satin LS, Sussel L, Stitzel ML, Soleimanpour SA. Retrograde mitochondrial signaling governs the identity and maturity of metabolic tissues. Science 2025; 388:eadf2034. [PMID: 39913641 PMCID: PMC11985298 DOI: 10.1126/science.adf2034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 09/13/2024] [Accepted: 01/07/2025] [Indexed: 02/13/2025]
Abstract
Mitochondrial damage is a hallmark of metabolic diseases, including diabetes, yet the consequences of compromised mitochondria in metabolic tissues are often unclear. In this work, we report that dysfunctional mitochondrial quality control engages a retrograde (mitonuclear) signaling program that impairs cellular identity and maturity in β cells, hepatocytes, and brown adipocytes. Targeted deficiency throughout the mitochondrial quality control pathway, including genome integrity, dynamics, or turnover, impaired the oxidative phosphorylation machinery, activating the mitochondrial integrated stress response, eliciting chromatin remodeling, and promoting cellular immaturity rather than apoptosis to yield metabolic dysfunction. Pharmacologic blockade of the integrated stress response in vivo restored β cell identity after the loss of mitochondrial quality control. Targeting mitochondrial retrograde signaling may therefore be promising in the treatment or prevention of metabolic disorders.
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Affiliation(s)
- Emily M. Walker
- Division of Metabolism, Endocrinology & Diabetes and Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Gemma L. Pearson
- Division of Metabolism, Endocrinology & Diabetes and Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Nathan Lawlor
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
- Department of Genetics and Genome Sciences, UConn Health, Farmington, CT, USA
| | - Ava M. Stendahl
- Division of Metabolism, Endocrinology & Diabetes and Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Anne Lietzke
- Division of Metabolism, Endocrinology & Diabetes and Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Vaibhav Sidarala
- Division of Metabolism, Endocrinology & Diabetes and Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Jie Zhu
- Division of Metabolism, Endocrinology & Diabetes and Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Tracy Stromer
- Division of Metabolism, Endocrinology & Diabetes and Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Emma C. Reck
- Division of Metabolism, Endocrinology & Diabetes and Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Jin Li
- Division of Metabolism, Endocrinology & Diabetes and Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Elena Levi-D’Ancona
- Division of Metabolism, Endocrinology & Diabetes and Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Mabelle B. Pasmooij
- Division of Metabolism, Endocrinology & Diabetes and Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Dre L. Hubers
- Division of Metabolism, Endocrinology & Diabetes and Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Aaron Renberg
- Division of Metabolism, Endocrinology & Diabetes and Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Kawthar Mohamed
- Division of Metabolism, Endocrinology & Diabetes and Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Vishal S. Parekh
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Irina X. Zhang
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Benjamin Thompson
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Deqiang Zhang
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Sarah A. Ware
- Vascular Medicine Institute, Division of Cardiology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Leena Haataja
- Division of Metabolism, Endocrinology & Diabetes and Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Nathan Qi
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Stephen C. J. Parker
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes and Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Lei Yin
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Brett A. Kaufman
- Vascular Medicine Institute, Division of Cardiology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Leslie S. Satin
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Lori Sussel
- Barbara Davis Center for Diabetes, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Michael L. Stitzel
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
- Department of Genetics and Genome Sciences, UConn Health, Farmington, CT, USA
| | - Scott A. Soleimanpour
- Division of Metabolism, Endocrinology & Diabetes and Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
- VA Ann Arbor Healthcare System, Ann Arbor, MI, USA
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2
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Wong A, Alejandro EU. Post translational modification regulation of transcription factors governing pancreatic β-cell identity and functional mass. Front Endocrinol (Lausanne) 2025; 16:1562646. [PMID: 40134803 PMCID: PMC11932907 DOI: 10.3389/fendo.2025.1562646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2025] [Accepted: 02/17/2025] [Indexed: 03/27/2025] Open
Abstract
Dysfunction of the insulin-secreting β-cells is a key hallmark of Type 2 diabetes (T2D). In the natural history of the progression of T2D, factors such as genetics, early life exposures, lifestyle, and obesity dictate an individual's susceptibility risk to disease. Obesity is associated with insulin resistance and increased demand for insulin to maintain glucose homeostasis. Studies in both mouse and human islets have implicated the β-cell's ability to compensate through proliferation and survival (increasing functional β-cell mass) as a tipping point toward the development of disease. A growing body of evidence suggests the reduction of β-cell mass in T2D is driven majorly by loss of β-cell identity, rather than by apoptosis alone. The development and maintenance of pancreatic β-cell identity, function, and adaptation to stress is governed, in part, by the spatiotemporal expression of transcription factors (TFs), whose activity is regulated by signal-dependent post-translational modifications (PTM). In this review, we examine the role of these TFs in the developing pancreas and in the mature β-cell. We discuss functional implications of post-translational modifications on these transcription factors' activities and how an understanding of the pathways they regulate can inform therapies to promoteβ-cell regeneration, proliferation, and survival in diabetes.
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Affiliation(s)
- Alicia Wong
- Department of Genetics, Cell Biology, and Development, University of Minnesota Twin Cities, Minneapolis, MN, United States
| | - Emilyn U. Alejandro
- Department of Integrative Biology and Physiology, University of Minnesota Twin Cities, Minneapolis, MN, United States
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3
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Jo S, Esch N, Nguyen A, Wong A, Mohan R, Kim C, Blandino-Rosano M, Bernal-Mizrachi E, Alejandro EU. Loss of O-GlcNAcylation modulates mTORC1 and autophagy in β cells, driving diabetes 2 progression. JCI Insight 2024; 9:e183033. [PMID: 39388284 PMCID: PMC11623944 DOI: 10.1172/jci.insight.183033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2024] [Accepted: 10/08/2024] [Indexed: 10/12/2024] Open
Abstract
Type 2 diabetes (T2D) arises when pancreatic β cells fail to produce sufficient insulin to control blood glucose appropriately. Aberrant nutrient sensing by O-GlcNAcylation and mTORC1 is linked to T2D and the failure of insulin-producing β cells. However, the nature of their crosstalk in β cells remains unexplored. Recently, O-GlcNAcylation, a posttranslation modification controlled by enzymes O-GlcNAc transferase/O-GlcNAcase (OGT/OGA), emerged as a pivotal regulator for β cell health; deficiency in either enzyme causes β cell failure. The present study investigates the previously unidentified connection between nutrient sensor OGT and mTORC1 crosstalk to regulate β cell mass and function in vivo. We show reduced OGT and mTORC1 activity in islets of a preclinical β cell dysfunction model and islets from humans with obesity. Using loss or gain of function of OGT, we identified that O-GlcNAcylation positively regulated mTORC1 signaling in β cells. O-GlcNAcylation negatively modulated autophagy, as the removal of OGT increased autophagy, while the deletion of OGA decreased it. Increasing mTORC1 signaling, via deletion of TSC2, alleviated the diabetic phenotypes by increasing β cell mass but not β cell function in OGT-deficient mice. Downstream phospho-protein signaling analyses revealed diverging effects on MKK4 and calmodulin signaling between islets with OGT, TSC2, or combined deletion. These data provide evidence of OGT's significance as an upstream regulator of mTORC1 and autophagy, crucial for the regulation of β cell function and glucose homeostasis.
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Affiliation(s)
- Seokwon Jo
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Nicholas Esch
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Anh Nguyen
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Alicia Wong
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Ramkumar Mohan
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Clara Kim
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Manuel Blandino-Rosano
- Department of Internal Medicine, Division of Endocrinology, Metabolism and Diabetes, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Ernesto Bernal-Mizrachi
- Department of Internal Medicine, Division of Endocrinology, Metabolism and Diabetes, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Emilyn U. Alejandro
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
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4
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Cheng SS, Mody AC, Woo CM. Opportunities for Therapeutic Modulation of O-GlcNAc. Chem Rev 2024; 124:12918-13019. [PMID: 39509538 DOI: 10.1021/acs.chemrev.4c00417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2024]
Abstract
O-Linked β-N-acetylglucosamine (O-GlcNAc) is an essential, dynamic monosaccharide post-translational modification (PTM) found on serine and threonine residues of thousands of nucleocytoplasmic proteins. The installation and removal of O-GlcNAc is controlled by a single pair of enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), respectively. Since its discovery four decades ago, O-GlcNAc has been found on diverse classes of proteins, playing important functional roles in many cellular processes. Dysregulation of O-GlcNAc homeostasis has been implicated in the pathogenesis of disease, including neurodegeneration, X-linked intellectual disability (XLID), cancer, diabetes, and immunological disorders. These foundational studies of O-GlcNAc in disease biology have motivated efforts to target O-GlcNAc therapeutically, with multiple clinical candidates under evaluation. In this review, we describe the characterization and biochemistry of OGT and OGA, cellular O-GlcNAc regulation, development of OGT and OGA inhibitors, O-GlcNAc in pathophysiology, clinical progress of O-GlcNAc modulators, and emerging opportunities for targeting O-GlcNAc. This comprehensive resource should motivate further study into O-GlcNAc function and inspire strategies for therapeutic modulation of O-GlcNAc.
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Affiliation(s)
- Steven S Cheng
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Alison C Mody
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Christina M Woo
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
- Affiliate member of the Broad Institute, Cambridge, Massachusetts 02142, United States
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5
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Niu F, Liu W, Ren Y, Tian Y, Shi W, Li M, Li Y, Xiong Y, Qian L. β-cell neogenesis: A rising star to rescue diabetes mellitus. J Adv Res 2024; 62:71-89. [PMID: 37839502 PMCID: PMC11331176 DOI: 10.1016/j.jare.2023.10.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 10/08/2023] [Accepted: 10/08/2023] [Indexed: 10/17/2023] Open
Abstract
BACKGROUND Diabetes Mellitus (DM), a chronic metabolic disease characterized by elevated blood glucose, is caused by various degrees of insulin resistance and dysfunctional insulin secretion, resulting in hyperglycemia. The loss and failure of functional β-cells are key mechanisms resulting in type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM). AIM OF REVIEW Elucidating the underlying mechanisms of β-cell failure, and exploring approaches for β-cell neogenesis to reverse β-cell dysfunction may provide novel strategies for DM therapy. KEY SCIENTIFIC CONCEPTS OF REVIEW Emerging studies reveal that genetic susceptibility, endoplasmic reticulum (ER) stress, oxidative stress, islet inflammation, and protein modification linked to multiple signaling pathways contribute to DM pathogenesis. Over the past few years, replenishing functional β-cell by β-cell neogenesis to restore the number and function of pancreatic β-cells has remarkably exhibited a promising therapeutic approach for DM therapy. In this review, we provide a comprehensive overview of the underlying mechanisms of β-cell failure in DM, highlight the effective approaches for β-cell neogenesis, as well as discuss the current clinical and preclinical agents research advances of β-cell neogenesis. Insights into the challenges of translating β-cell neogenesis into clinical application for DM treatment are also offered.
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Affiliation(s)
- Fanglin Niu
- Xi'an Key Laboratory of Cardiovascular and Cerebrovascular Diseases, the Affiliated Hospital of Northwest University, Xi'an No.3 Hospital, Xi'an, Shaanxi, PR China; Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, Northwest University, Xi'an, China
| | - Wenxuan Liu
- Xi'an Key Laboratory of Cardiovascular and Cerebrovascular Diseases, the Affiliated Hospital of Northwest University, Xi'an No.3 Hospital, Xi'an, Shaanxi, PR China; Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, Northwest University, Xi'an, China
| | - Yuanyuan Ren
- Xi'an Key Laboratory of Cardiovascular and Cerebrovascular Diseases, the Affiliated Hospital of Northwest University, Xi'an No.3 Hospital, Xi'an, Shaanxi, PR China; Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, Northwest University, Xi'an, China
| | - Ye Tian
- Xi'an Key Laboratory of Cardiovascular and Cerebrovascular Diseases, the Affiliated Hospital of Northwest University, Xi'an No.3 Hospital, Xi'an, Shaanxi, PR China; Department of Neurology, Affiliated Hospital of Northwest University, Xi'an No.3 Hospital, Xi'an, Shaanxi, China
| | - Wenzhen Shi
- Xi'an Key Laboratory of Cardiovascular and Cerebrovascular Diseases, the Affiliated Hospital of Northwest University, Xi'an No.3 Hospital, Xi'an, Shaanxi, PR China; Medical Research Center, the affiliated Hospital of Northwest University, Xi'an No.3 Hospital, Xi'an, Shaanxi, China
| | - Man Li
- Department of Endocrinology, the Affiliated Hospital of Northwest University, Xi'an No.3 Hospital, Xi'an, Shaanxi, China
| | - Yujia Li
- Department of Endocrinology, the Affiliated Hospital of Northwest University, Xi'an No.3 Hospital, Xi'an, Shaanxi, China
| | - Yuyan Xiong
- Xi'an Key Laboratory of Cardiovascular and Cerebrovascular Diseases, the Affiliated Hospital of Northwest University, Xi'an No.3 Hospital, Xi'an, Shaanxi, PR China; Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, Northwest University, Xi'an, China
| | - Lu Qian
- Xi'an Key Laboratory of Cardiovascular and Cerebrovascular Diseases, the Affiliated Hospital of Northwest University, Xi'an No.3 Hospital, Xi'an, Shaanxi, PR China; Department of Endocrinology, the Affiliated Hospital of Northwest University, Xi'an No.3 Hospital, Xi'an, Shaanxi, China
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6
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Dobson JR, Jacobson DA. Disrupted Endoplasmic Reticulum Ca 2+ Handling: A Harβinger of β-Cell Failure. BIOLOGY 2024; 13:379. [PMID: 38927260 PMCID: PMC11200644 DOI: 10.3390/biology13060379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 05/17/2024] [Accepted: 05/17/2024] [Indexed: 06/28/2024]
Abstract
The β-cell workload increases in the setting of insulin resistance and reduced β-cell mass, which occurs in type 2 and type 1 diabetes, respectively. The prolonged elevation of insulin production and secretion during the pathogenesis of diabetes results in β-cell ER stress. The depletion of β-cell Ca2+ER during ER stress activates the unfolded protein response, leading to β-cell dysfunction. Ca2+ER is involved in many pathways that are critical to β-cell function, such as protein processing, tuning organelle and cytosolic Ca2+ handling, and modulating lipid homeostasis. Mutations that promote β-cell ER stress and deplete Ca2+ER stores are associated with or cause diabetes (e.g., mutations in ryanodine receptors and insulin). Thus, improving β-cell Ca2+ER handling and reducing ER stress under diabetogenic conditions could preserve β-cell function and delay or prevent the onset of diabetes. This review focuses on how mechanisms that control β-cell Ca2+ER are perturbed during the pathogenesis of diabetes and contribute to β-cell failure.
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Affiliation(s)
| | - David A. Jacobson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA;
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7
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Sue N, Thai LM, Saito A, Boyer CK, Fordham AM, Yan C, Davenport A, Tao J, Bensellam M, Cantley J, Shi YC, Stephens SB, Imaizumi K, Biden TJ. Independent activation of CREB3L2 by glucose fills a regulatory gap in mouse β-cells by co-ordinating insulin biosynthesis with secretory granule formation. Mol Metab 2024; 79:101845. [PMID: 38013154 PMCID: PMC10755490 DOI: 10.1016/j.molmet.2023.101845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 11/22/2023] [Accepted: 11/23/2023] [Indexed: 11/29/2023] Open
Abstract
OBJECTIVE Although individual steps have been characterized, there is little understanding of the overall process whereby glucose co-ordinates the biosynthesis of insulin with its export out of the endoplasmic reticulum (ER) and incorporation into insulin secretory granules (ISGs). Here we investigate a role for the transcription factor CREB3L2 in this context. METHODS MIN6 cells and mouse islets were analysed by immunoblotting after treatment with glucose, fatty acids, thapsigargin and various inhibitors. Knockdown of CREB3L2 was achieved using si or sh constructs by transfection, or viral delivery. In vivo metabolic phenotyping was conducted after deletion of CREB3L2 in β-cells of adult mice using Ins1-CreER+. Islets were isolated for RNAseq and assays of glucose-stimulated insulin secretion (GSIS). Trafficking was monitored in islet monolayers using a GFP-tagged proinsulin construct that allows for synchronised release from the ER. RESULTS With a Km ≈3.5 mM, glucose rapidly (T1/2 0.9 h) increased full length (FL) CREB3L2 followed by a slower rise (T1/2 2.5 h) in its transcriptionally-active cleavage product, P60 CREB3L2. Glucose stimulation repressed the ER stress marker, CHOP, and this was partially reverted by knockdown of CREB3L2. Activation of CREB3L2 by glucose was not due to ER stress, however, but a combination of O-GlcNAcylation, which impaired proteasomal degradation of FL-CREB3L2, and mTORC1 stimulation, which enhanced its conversion to P60. cAMP generation also activated CREB3L2, but independently of glucose. Deletion of CREB3L2 inhibited GSIS ex vivo and, following a high-fat diet (HFD), impaired glucose tolerance and insulin secretion in vivo. RNAseq revealed that CREB3L2 regulated genes controlling trafficking to-and-from the Golgi, as well as a broader cohort associated with β-cell compensation during a HFD. Although post-Golgi trafficking appeared intact, knockdown of CREB3L2 impaired the generation of both nascent ISGs and proinsulin condensates in the Golgi, implying a defect in ER export of proinsulin and/or its processing in the Golgi. CONCLUSION The stimulation of CREB3L2 by glucose defines a novel, rapid and direct mechanism for co-ordinating the synthesis, packaging and storage of insulin, thereby minimizing ER overload and optimizing β-cell function under conditions of high secretory demand. Upregulation of CREB3L2 also potentially contributes to the benefits of GLP1 agonism and might in itself constitute a novel means of treating β-cell failure.
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Affiliation(s)
- Nancy Sue
- Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW 2010, Australia
| | - Le May Thai
- Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW 2010, Australia
| | - Atsushi Saito
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Cierra K Boyer
- Fraternal Order of Eagles Diabetes Research Center, Department of Internal Medicine, University of Iowa, Iowa City, IA 52246, USA
| | - Ashleigh M Fordham
- Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW 2010, Australia
| | - Chenxu Yan
- Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW 2010, Australia
| | - Aimee Davenport
- Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW 2010, Australia
| | - Jiang Tao
- Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW 2010, Australia
| | - Mohammed Bensellam
- Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW 2010, Australia
| | - James Cantley
- Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW 2010, Australia
| | - Yan-Chuan Shi
- Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW 2010, Australia; St Vincent's Clinical School, Faculty of Medicine, The University of New South Wales, Sydney, Australia
| | - Samuel B Stephens
- Fraternal Order of Eagles Diabetes Research Center, Department of Internal Medicine, University of Iowa, Iowa City, IA 52246, USA
| | - Kazunori Imaizumi
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Trevor J Biden
- Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW 2010, Australia; St Vincent's Clinical School, Faculty of Medicine, The University of New South Wales, Sydney, Australia.
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8
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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: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [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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9
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Flanary SM, Jo S, Ravichandran R, Alejandro EU, Barocas VH. A computational bridge between traction force microscopy and tissue contraction. JOURNAL OF APPLIED PHYSICS 2023; 134:074901. [PMID: 37593660 PMCID: PMC10431945 DOI: 10.1063/5.0157507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 07/26/2023] [Indexed: 08/19/2023]
Abstract
Arterial wall active mechanics are driven by resident smooth muscle cells, which respond to biological, chemical, and mechanical stimuli and activate their cytoskeletal machinery to generate contractile stresses. The cellular mechanoresponse is sensitive to environmental perturbations, often leading to maladaptation and disease progression. When investigated at the single cell scale, however, these perturbations do not consistently result in phenotypes observed at the tissue scale. Here, a multiscale model is introduced that translates microscale contractility signaling into a macroscale, tissue-level response. The microscale framework incorporates a biochemical signaling network along with characterization of fiber networks that govern the anisotropic mechanics of vascular tissue. By incorporating both biochemical and mechanical components, the model is more flexible and more broadly applicable to physiological and pathological conditions. The model can be applied to both cell and tissue scale systems, allowing for the analysis of in vitro, traction force microscopy and ex vivo, isometric contraction experiments in parallel. When applied to aortic explant rings and isolated smooth muscle cells, the model predicts that active contractility is not a function of stretch at intermediate strain. The model also successfully predicts cell-scale and tissue-scale contractility and matches experimentally observed behaviors, including the hypercontractile phenotype caused by chronic hyperglycemia. The connection of the microscale framework to the macroscale through the multiscale model presents a framework that can translate the wealth of information already collected at the cell scale to tissue scale phenotypes, potentially easing the development of smooth muscle cell-targeting therapeutics.
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Affiliation(s)
- Shannon M. Flanary
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Seokwon Jo
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Rohit Ravichandran
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Emilyn U. Alejandro
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Victor H. Barocas
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA
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10
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Jo S, Beetch M, Gustafson E, Wong A, Oribamise E, Chung G, Vadrevu S, Satin LS, Bernal-Mizrachi E, Alejandro EU. Sex Differences in Pancreatic β-Cell Physiology and Glucose Homeostasis in C57BL/6J Mice. J Endocr Soc 2023; 7:bvad099. [PMID: 37873500 PMCID: PMC10590649 DOI: 10.1210/jendso/bvad099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Indexed: 10/25/2023] Open
Abstract
The importance of sexual dimorphism has been highlighted in recent years since the National Institutes of Health's mandate on considering sex as a biological variable. Although recent studies have taken strides to study both sexes side by side, investigations into the normal physiological differences between males and females are limited. In this study, we aimed to characterized sex-dependent differences in glucose metabolism and pancreatic β-cell physiology in normal conditions using C57BL/6J mice, the most common mouse strain used in metabolic studies. Here, we report that female mice have improved glucose and insulin tolerance associated with lower nonfasted blood glucose and insulin levels compared with male mice at 3 and 6 months of age. Both male and female animals show β-cell mass expansion from embryonic day 17.5 to adulthood, and no sex differences were observed at embryonic day 17.5, newborn, 1 month, or 3 months of age. However, 6-month-old males displayed increased β-cell mass in response to insulin resistance compared with littermate females. Molecularly, we uncovered sexual dimorphic alterations in the protein levels of nutrient sensing proteins O-GlcNAc transferase and mTOR, as well as differences in glucose-stimulus coupling mechanisms that may underlie the differences in sexually dimorphic β-cell physiology observed in C57BL/6J mice.
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Affiliation(s)
- Seokwon Jo
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Megan Beetch
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Eric Gustafson
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Alicia Wong
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Eunice Oribamise
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Grace Chung
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Suryakiran Vadrevu
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Leslie S Satin
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Ernesto Bernal-Mizrachi
- Diabetes, VA Ann Arbor Healthcare System, Ann Arbor, MI 48105, USA
- Miami VA Healthcare System and Division Endocrinology, Metabolism and Diabetes, University of Miami, Miami, FL 33125, USA
| | - Emilyn U Alejandro
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
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11
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Paneque A, Fortus H, Zheng J, Werlen G, Jacinto E. The Hexosamine Biosynthesis Pathway: Regulation and Function. Genes (Basel) 2023; 14:genes14040933. [PMID: 37107691 PMCID: PMC10138107 DOI: 10.3390/genes14040933] [Citation(s) in RCA: 68] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 04/13/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023] Open
Abstract
The hexosamine biosynthesis pathway (HBP) produces uridine diphosphate-N-acetyl glucosamine, UDP-GlcNAc, which is a key metabolite that is used for N- or O-linked glycosylation, a co- or post-translational modification, respectively, that modulates protein activity and expression. The production of hexosamines can occur via de novo or salvage mechanisms that are catalyzed by metabolic enzymes. Nutrients including glutamine, glucose, acetyl-CoA, and UTP are utilized by the HBP. Together with availability of these nutrients, signaling molecules that respond to environmental signals, such as mTOR, AMPK, and stress-regulated transcription factors, modulate the HBP. This review discusses the regulation of GFAT, the key enzyme of the de novo HBP, as well as other metabolic enzymes that catalyze the reactions to produce UDP-GlcNAc. We also examine the contribution of the salvage mechanisms in the HBP and how dietary supplementation of the salvage metabolites glucosamine and N-acetylglucosamine could reprogram metabolism and have therapeutic potential. We elaborate on how UDP-GlcNAc is utilized for N-glycosylation of membrane and secretory proteins and how the HBP is reprogrammed during nutrient fluctuations to maintain proteostasis. We also consider how O-GlcNAcylation is coupled to nutrient availability and how this modification modulates cell signaling. We summarize how deregulation of protein N-glycosylation and O-GlcNAcylation can lead to diseases including cancer, diabetes, immunodeficiencies, and congenital disorders of glycosylation. We review the current pharmacological strategies to inhibit GFAT and other enzymes involved in the HBP or glycosylation and how engineered prodrugs could have better therapeutic efficacy for the treatment of diseases related to HBP deregulation.
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Affiliation(s)
- Alysta Paneque
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Harvey Fortus
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Julia Zheng
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Guy Werlen
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Estela Jacinto
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
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12
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Wong A, Pritchard S, Moore M, Akhaphong B, Avula N, Beetch M, Fujitani Y, Alejandro EU. Overexpression of Pdx1, reduction of p53, or deletion of CHOP attenuates pancreas hypoplasia in mice with pancreas-specific O-GlcNAc transferase deletion. J Biol Chem 2023; 299:102878. [PMID: 36623733 PMCID: PMC9932656 DOI: 10.1016/j.jbc.2023.102878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/16/2022] [Accepted: 12/17/2022] [Indexed: 01/09/2023] Open
Abstract
Deletion of O-GlcNAc transferase (Ogt) in pancreatic epithelial progenitor cells results in pancreatic hypoplasia at birth, partly due to increased apoptosis during embryonic development. Constitutive loss of Ogt in β-cells results in increased ER stress and apoptosis, and in the Ogt-deficient pancreas, transcriptomic data previously revealed both tumor suppressor protein p53 and pancreatic duodenal homeobox 1 (Pdx1), key cell survival proteins in the developing pancreas, as upstream regulators of differentially expressed genes. However, the specific roles of these genes in pancreatic hypoplasia are unclear. In this study, we explored the independent roles of p53, ER stress protein CHOP, and Pdx1 in pancreas development and their use in the functional rescue of pancreatic hypoplasia in the context of Ogt loss. Using in vivo genetic manipulation and morphometric analysis, we show that Ogt plays a key regulatory role in pancreas development. Heterozygous, but not homozygous, loss of pancreatic p53 afforded a partial rescue of β-cell, α-cell, and exocrine cell masses, while whole body loss of CHOP afforded a partial rescue in pancreas weight and a full rescue in exocrine cell mass. However, neither was sufficient to fully mitigate pancreatic hypoplasia at birth in the Ogt-deficient pancreas. Furthermore, overexpression of Pdx1 in the pancreatic epithelium resulted in partial rescues in pancreas weight and β-cell mass in the Ogt loss background. These findings highlight the requirement of Ogt in pancreas development by targeting multiple proteins such as transcription factor Pdx1 and p53 in the developing pancreas.
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Affiliation(s)
- Alicia Wong
- Department of Integrative Biology & Physiology, University of Minnesota, Minneapolis, Minnesota, USA; Department of Genetics, Cell Biology & Development, University of Minnesota, Minneapolis, Minnesota, USA
| | - Samantha Pritchard
- Department of Integrative Biology & Physiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Mackenzie Moore
- Department of Integrative Biology & Physiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Brian Akhaphong
- Department of Integrative Biology & Physiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Nandini Avula
- Department of Integrative Biology & Physiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Megan Beetch
- Department of Integrative Biology & Physiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Yoshio Fujitani
- Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan
| | - Emilyn U Alejandro
- Department of Integrative Biology & Physiology, University of Minnesota, Minneapolis, Minnesota, USA.
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13
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Wong A, Akhaphong B, Baumann D, Alejandro EU. Genetic Ablation of the Nutrient Sensor Ogt in Endocrine Progenitors Is Dispensable for β-Cell Development but Essential for Maintenance of β-Cell Mass. Biomedicines 2022; 11:105. [PMID: 36672613 PMCID: PMC9855876 DOI: 10.3390/biomedicines11010105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 12/20/2022] [Accepted: 12/29/2022] [Indexed: 01/03/2023] Open
Abstract
Previously we utilized a murine model to demonstrate that Ogt deletion in pancreatic progenitors (OgtKOPanc) causes pancreatic hypoplasia, partly mediated by a reduction in the Pdx1-expressing pancreatic progenitor pool. Here, we continue to explore the role of Ogt in pancreas development by deletion of Ogt in the endocrine progenitors (OgtKOEndo). At birth OgtKOEndo, were normoglycemic and had comparable pancreas weight and α-cell, and β-cell mass to littermate controls. At postnatal day 23, OgtKOEndo displayed wide ranging but generally elevated blood glucose levels, with histological analyses showing aberrant islet architecture with α-cells invading the islet core. By postnatal day 60, these mice were overtly diabetic and showed significant loss of both α-cell and β-cell mass. Together, these results highlight the indispensable role of Ogt in maintenance of β-cell mass and glucose homeostasis.
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Affiliation(s)
- Alicia Wong
- Department of Genetics, Cell Biology, and Development, University of Minnesota Twin Cities, Minneapolis, MN 55455, USA
| | - Brian Akhaphong
- Department of Integrative Biology and Physiology, University of Minnesota Twin Cities, Minneapolis, MN 55455, USA
| | - Daniel Baumann
- Department of Integrative Biology and Physiology, University of Minnesota Twin Cities, Minneapolis, MN 55455, USA
| | - Emilyn U. Alejandro
- Department of Integrative Biology and Physiology, University of Minnesota Twin Cities, Minneapolis, MN 55455, USA
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14
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Hong H, Lin X, Xu Y, Tong T, Zhang J, He H, Yang L, Lu Y, Zhou Z. Cadmium induces ferroptosis mediated inflammation by activating Gpx4/Ager/p65 axis in pancreatic β-cells. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 849:157819. [PMID: 35931150 DOI: 10.1016/j.scitotenv.2022.157819] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/26/2022] [Accepted: 07/31/2022] [Indexed: 06/15/2023]
Abstract
Cadmium (Cd) is a widely distributed endocrine disruptor and has been reported to be closely correlated to the pathogenesis of diabetes. Since pancreatic β-cells loss and dysfunction are central to pathogenesis of diabetes, studying Cd toxicity on pancreatic β-cells and its molecular mechanism is an important scientific issue. However, less attention has been payed to study how Cd induces pancreatic β-cells death and dysfunction in recent years. Thus, our study aims to explore the toxic mechanism of Cd treatment on pancreatic β-cells using both cellular and animal models. Firstly, it was confirmed that Cd induced decreased cell viability and insulin secretion in a dose-and time-dependent manner in MIN6 cells. To explore the underlying mechanism, transcriptomic analysis was employed to screen the differentially expressed genes and disturbed metabolic pathways. Go and KEGG analysis showed that Cd exposure triggered ferroptosis process in MIN6 cells. We further validated that Cd led to GSH depletion, Gpx4 reduction, lipid peroxidation, mitochondrial membrane potential loss and ultrastructural damage at mitochondrial level. Since immune system process was also perturbed based on GO analysis, we found that Cd activated Ager/Pkc/p65 inflammatory process. Moreover, ferroptosis inhibitor Fer-1 could effectively antagonized the activation of Ager-mediated immune process. It was also revealed that Cd induced iron accumulation as well as decreased Gpx4 expression in mice islets. We also uncovered that Cd led to systemic and pancreatic inflammation as early as third week after Cd exposure. Our study emphasizes the importance of ferroptotic cell death on Cd-induced systemic chronic inflammation. A novel target is provided to prevent Cd-induced pancreatic β-cells dysfunction and improve the chronic inflammatory state for prediabetes prevention.
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Affiliation(s)
- Huihui Hong
- Department of Emergency Medicine of First Affiliated Hospital and Department of Environmental Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiqin Lin
- Department of Emergency Medicine of First Affiliated Hospital and Department of Environmental Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Yudong Xu
- Department of Emergency Medicine of First Affiliated Hospital and Department of Environmental Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Tong Tong
- Department of Emergency Medicine of First Affiliated Hospital and Department of Environmental Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Jingjing Zhang
- Department of Emergency Medicine of First Affiliated Hospital and Department of Environmental Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Haotian He
- Department of Emergency Medicine of First Affiliated Hospital and Department of Environmental Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Lingling Yang
- Department of Occupational Health, Third Military Medical University, Chongqing, China
| | - Yuanqiang Lu
- Department of Emergency Medicine, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China; Zhejiang Provincial Key Laboratory for Diagnosis and Treatment of Aging and Physic-chemical Injury Diseases, Hangzhou, China.
| | - Zhou Zhou
- Department of Emergency Medicine of First Affiliated Hospital and Department of Environmental Medicine, Zhejiang University School of Medicine, Hangzhou, China.
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15
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Fahie KMM, Papanicolaou KN, Zachara NE. Integration of O-GlcNAc into Stress Response Pathways. Cells 2022; 11:3509. [PMID: 36359905 PMCID: PMC9654274 DOI: 10.3390/cells11213509] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/31/2022] [Accepted: 11/02/2022] [Indexed: 11/09/2022] Open
Abstract
The modification of nuclear, mitochondrial, and cytosolic proteins by O-linked βN-acetylglucosamine (O-GlcNAc) has emerged as a dynamic and essential post-translational modification of mammalian proteins. O-GlcNAc is cycled on and off over 5000 proteins in response to diverse stimuli impacting protein function and, in turn, epigenetics and transcription, translation and proteostasis, metabolism, cell structure, and signal transduction. Environmental and physiological injury lead to complex changes in O-GlcNAcylation that impact cell and tissue survival in models of heat shock, osmotic stress, oxidative stress, and hypoxia/reoxygenation injury, as well as ischemic reperfusion injury. Numerous mechanisms that appear to underpin O-GlcNAc-mediated survival include changes in chaperone levels, impacts on the unfolded protein response and integrated stress response, improvements in mitochondrial function, and reduced protein aggregation. Here, we discuss the points at which O-GlcNAc is integrated into the cellular stress response, focusing on the roles it plays in the cardiovascular system and in neurodegeneration.
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Affiliation(s)
- Kamau M. M. Fahie
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Kyriakos N. Papanicolaou
- Department of Medicine, Division of Cardiology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Natasha E. Zachara
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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16
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Jo S, Pritchard S, Wong A, Avula N, Essawy A, Hanover J, Alejandro EU. Pancreatic β-cell hyper-O-GlcNAcylation leads to impaired glucose homeostasis in vivo. Front Endocrinol (Lausanne) 2022; 13:1040014. [PMID: 36387851 PMCID: PMC9644030 DOI: 10.3389/fendo.2022.1040014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 10/10/2022] [Indexed: 11/13/2022] Open
Abstract
Protein O-GlcNAcylation is a nutrient and stress-sensitive protein post-translational modification (PTM). The addition of an O-GlcNAc molecule to proteins is catalyzed by O-GlcNAc transferase (OGT), whereas O-GlcNAcase (OGA) enzyme is responsible for removal of this PTM. Previous work showed that OGT is highly expressed in the pancreas, and we demonstrated that hypo-O-GlcNAcylation in β-cells cause severe diabetes in mice. These studies show a direct link between nutrient-sensitive OGT and β-cell health and function. In the current study, we hypothesized that hyper-O-GlcNAcylation may confer protection from β-cell failure in high-fat diet (HFD)-induced obesity. To test this hypothesis, we generated a mouse model with constitutive β-cell OGA ablation (βOGAKO) to specifically increase O-GlcNAcylation in β-cells. Under normal chow diet, young male and female βOGAKO mice exhibited normal glucose tolerance but developed glucose intolerance with aging, relative to littermate controls. No alteration in β-cell mass was observed between βOGAKO and littermate controls. Total insulin content was reduced despite an increase in pro-insulin to insulin ratio in βOGAKO islets. βOGAKO mice showed deficit in insulin secretion in vivo and in vitro. When young animals were subjected to HFD, both male and female βOGAKO mice displayed normal body weight gain and insulin tolerance but developed glucose intolerance that worsened with longer exposure to HFD. Comparable β-cell mass was found between βOGAKO and littermate controls. Taken together, these data demonstrate that the loss of OGA in β-cells reduces β-cell function, thereby perturbing glucose homeostasis. The findings reinforce the rheostat model of intracellular O-GlcNAcylation where too much (OGA loss) or too little (OGT loss) O-GlcNAcylation are both detrimental to the β-cell.
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Affiliation(s)
- Seokwon Jo
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, Minneapolis, MN, United States
| | - Samantha Pritchard
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, Minneapolis, MN, United States
| | - Alicia Wong
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, Minneapolis, MN, United States
- Department of Genetics, Cell Biology & Development, University of Minnesota, Minneapolis, MN, United States
| | - Nandini Avula
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, Minneapolis, MN, United States
| | - Ahmad Essawy
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, Minneapolis, MN, United States
| | - John Hanover
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, United States
| | - Emilyn U. Alejandro
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, Minneapolis, MN, United States
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17
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Hu A, Zou H, Chen B, Zhong J. Posttranslational modifications in diabetes: Mechanisms and functions. Rev Endocr Metab Disord 2022; 23:1011-1033. [PMID: 35697961 DOI: 10.1007/s11154-022-09740-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/20/2022] [Indexed: 12/15/2022]
Abstract
As one of the most widespread chronic diseases, diabetes and its accompanying complications affect approximately one tenth of individuals worldwide and represent a growing cause of morbidity and mortality. Accumulating evidence has proven that the process of diabetes is complex and interactive, involving various cellular responses and signaling cascades by posttranslational modifications (PTMs). Therefore, understanding the mechanisms and functions of PTMs in regulatory networks has fundamental importance for understanding the prediction, onset, diagnosis, progression, and treatment of diabetes. In this review, we offer a holistic summary and illustration of the crosstalk between PTMs and diabetes, including both types 1 and 2. Meanwhile, we discuss the potential use of PTMs in diabetes treatment and provide a prospective direction for deeply understanding the metabolic diseases.
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Affiliation(s)
- Ang Hu
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases, Ministry of Education, Gannan Medical University, 323 National Road, Ganzhou, 341000, Jiangxi, China
| | - Haohong Zou
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases, Ministry of Education, Gannan Medical University, 323 National Road, Ganzhou, 341000, Jiangxi, China
| | - Bin Chen
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases, Ministry of Education, Gannan Medical University, 323 National Road, Ganzhou, 341000, Jiangxi, China
- The First Affiliated Hospital of Gannan Medical University, Ganzhou, China
| | - Jianing Zhong
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases, Ministry of Education, Gannan Medical University, 323 National Road, Ganzhou, 341000, Jiangxi, China.
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18
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Protein O-GlcNAcylation and the regulation of energy homeostasis: lessons from knock-out mouse models. J Biomed Sci 2022; 29:64. [PMID: 36058931 PMCID: PMC9443036 DOI: 10.1186/s12929-022-00851-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 08/30/2022] [Indexed: 12/02/2022] Open
Abstract
O-GlcNAcylation corresponds to the addition of N-Acetylglucosamine (GlcNAc) on serine or threonine residues of cytosolic, nuclear and mitochondrial proteins. This reversible modification is catalysed by a unique couple of enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). OGT uses UDP-GlcNAc produced in the hexosamine biosynthesis pathway, to modify proteins. UDP-GlcNAc is at the cross-roads of several cellular metabolisms, including glucose, amino acids and fatty acids. Therefore, OGT is considered as a metabolic sensor that post-translationally modifies proteins according to nutrient availability. O-GlcNAcylation can modulate protein–protein interactions and regulate protein enzymatic activities, stability or subcellular localization. In addition, it can compete with phosphorylation on the same serine or threonine residues, or regulate positively or negatively the phosphorylation of adjacent residues. As such, O-GlcNAcylation is a major actor in the regulation of cell signaling and has been implicated in numerous physiological and pathological processes. A large body of evidence have indicated that increased O-GlcNAcylation participates in the deleterious effects of glucose (glucotoxicity) in metabolic diseases. However, recent studies using mice models with OGT or OGA knock-out in different tissues have shown that O-GlcNAcylation protects against various cellular stresses, and indicate that both increase and decrease in O-GlcNAcylation have deleterious effects on the regulation of energy homeostasis.
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19
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Lockridge A, Hanover JA. A nexus of lipid and O-Glcnac metabolism in physiology and disease. Front Endocrinol (Lausanne) 2022; 13:943576. [PMID: 36111295 PMCID: PMC9468787 DOI: 10.3389/fendo.2022.943576] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 07/27/2022] [Indexed: 11/13/2022] Open
Abstract
Although traditionally considered a glucose metabolism-associated modification, the O-linked β-N-Acetylglucosamine (O-GlcNAc) regulatory system interacts extensively with lipids and is required to maintain lipid homeostasis. The enzymes of O-GlcNAc cycling have molecular properties consistent with those expected of broad-spectrum environmental sensors. By direct protein-protein interactions and catalytic modification, O-GlcNAc cycling enzymes may provide both acute and long-term adaptation to stress and other environmental stimuli such as nutrient availability. Depending on the cell type, hyperlipidemia potentiates or depresses O-GlcNAc levels, sometimes biphasically, through a diversity of unique mechanisms that target UDP-GlcNAc synthesis and the availability, activity and substrate selectivity of the glycosylation enzymes, O-GlcNAc Transferase (OGT) and O-GlcNAcase (OGA). At the same time, OGT activity in multiple tissues has been implicated in the homeostatic regulation of systemic lipid uptake, storage and release. Hyperlipidemic patterns of O-GlcNAcylation in these cells are consistent with both transient physiological adaptation and feedback uninhibited obesogenic and metabolic dysregulation. In this review, we summarize the numerous interconnections between lipid and O-GlcNAc metabolism. These links provide insights into how the O-GlcNAc regulatory system may contribute to lipid-associated diseases including obesity and metabolic syndrome.
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Affiliation(s)
- Amber Lockridge
- Laboratory of Cell and Molecular Biology, National Institute for Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - John A. Hanover
- Laboratory of Cell and Molecular Biology, National Institute for Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
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20
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Na HJ, Abramowitz LK, Hanover JA. Cytosolic O-GlcNAcylation and PNG1 maintain Drosophila gut homeostasis by regulating proliferation and apoptosis. PLoS Genet 2022; 18:e1010128. [PMID: 35294432 PMCID: PMC8959174 DOI: 10.1371/journal.pgen.1010128] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 03/28/2022] [Accepted: 03/02/2022] [Indexed: 11/29/2022] Open
Abstract
Tissue homeostasis requires a delicate balance between stem cell self-renewal, proliferation, and differentiation. Essential to this process is glycosylation, with both intra-and extra-cellular glycosylation being required for stem cell homeostasis. However, it remains unknown how intracellular glycosylation, O-GlcNAcylation, interfaces with cellular components of the extracellular glycosylation machinery, like the cytosolic N-glycanase NGLY1. In this study, we utilize the Drosophila gut and uncover a pathway in which O-GlcNAcylation cooperates with the NGLY1 homologue PNG1 to regulate proliferation in intestinal stem cells (ISCs) and apoptosis in differentiated enterocytes. Further, the CncC antioxidant signaling pathway and ENGase, an enzyme involved in the processing of free oligosaccharides in the cytosol, interact with O-GlcNAc and PNG1 through regulation of protein aggregates to contribute to gut maintenance. These findings reveal a complex coordinated regulation between O-GlcNAcylation and the cytosolic glycanase PNG1 critical to balancing proliferation and apoptosis to maintain gut homeostasis. Understanding glycosylation is of great importance as changes in both intra- and extra-cellular glycosylation have been well documented in diseases. However, it remains relatively unclear how intracellular glycosylation, O-GlcNAcylation, interfaces with the cellular machinery of extracellular glycosylation. In this study, we seek to understand how coordination between a cytosolic N-glycanase, NGLY1, and intracellular glycosylation, is utilized during stem cell proliferation. Using the Drosophila gut as a model system, our data showed O-GlcNAcylation and the Drosophila homologue of NGY1, PNG1, have key roles in both progenitor and differentiated cells that contribute to tissue homeostasis. Further, the CncC antioxidant signaling pathway and ENGase, an enzyme involved in the processing of free oligosaccharides in the cytosol, interact with O-GlcNAc and PNG1 through regulation of protein aggregates to contribute to gut maintenance. Our study suggests that alterations in O-GlcNAc and NGLY1 could be future targets utilized as therapeutics for nutrient-sensitive stem cell-derived diseases such as cancer.
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Affiliation(s)
- Hyun-jin Na
- Laboratory of Cellular and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Lara K. Abramowitz
- Laboratory of Cellular and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - John A. Hanover
- Laboratory of Cellular and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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21
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Moore M, Avula N, Wong A, Beetch M, Jo S, Alejandro EU. Reduction in O-GlcNAcylation Mitigates the Severity of Inflammatory Response in Cerulein-Induced Acute Pancreatitis in a Mouse Model. BIOLOGY 2022; 11:biology11030347. [PMID: 35336721 PMCID: PMC8945657 DOI: 10.3390/biology11030347] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 02/05/2022] [Accepted: 02/14/2022] [Indexed: 12/12/2022]
Abstract
Acute pancreatitis (AP) involves premature trypsinogen activation, which mediates a cascade of pro-inflammatory signaling that causes early stages of pancreatic injury. Activation of the transcription factor κB (NF-κB) and secretion of pro-inflammatory mediators are major events in AP. O-GlcNAc transferase (OGT), a stress-sensitive enzyme, was recently implicated to regulate NF-κB activation and inflammation in AP in vitro. This study aims to determine whether a pancreas-specific transgenic reduction in OGT in a mouse model affects the severity of AP in vivo. Mice with reduced pancreatic OGT (OGTPanc+/-) at 8 weeks of age were randomized to cerulein, which induces pancreatitis, or saline injections. AP was confirmed by elevated amylase levels and on histological analysis. The histological scoring demonstrated that OGTPanc+/- mice had decreased severity of AP. Additionally, serum lipase, LDH, and TNF-α in OGTPanc+/- did not significantly increase in response to cerulein treatment as compared to controls, suggesting attenuated AP induction in this model. Our study reveals the effect of reducing pancreatic OGT levels on the severity of pancreatitis, warranting further investigation on the role of OGT in the pathology of AP.
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Affiliation(s)
- Mackenzie Moore
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA; (M.M.); (N.A.); (M.B.); (S.J.)
- Department of Surgery, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Nandini Avula
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA; (M.M.); (N.A.); (M.B.); (S.J.)
| | - Alicia Wong
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA;
| | - Megan Beetch
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA; (M.M.); (N.A.); (M.B.); (S.J.)
| | - Seokwon Jo
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA; (M.M.); (N.A.); (M.B.); (S.J.)
| | - Emilyn U. Alejandro
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA; (M.M.); (N.A.); (M.B.); (S.J.)
- Correspondence: ; Tel.: +1-612-301-7685
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22
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O-GlcNAcylation regulation of cellular signaling in cancer. Cell Signal 2022; 90:110201. [PMID: 34800629 PMCID: PMC8712408 DOI: 10.1016/j.cellsig.2021.110201] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/12/2021] [Accepted: 11/15/2021] [Indexed: 02/03/2023]
Abstract
O-GlcNAcylation is a post-translational modification occurring on serine/threonine residues of nuclear and cytoplasmic proteins, mediated by the enzymes OGT and OGA which catalyze the addition or removal of the UDP-GlcNAc moieties, respectively. Structural changes brought by this modification lead to alternations of protein stability, protein-protein interactions, and phosphorylation. Importantly, O-GlcNAcylation is a nutrient sensor by coupling nutrient sensing with cellular signaling. Elevated levels of OGT and O-GlcNAc have been reported in a variety of cancers and has been linked to regulation of multiple cancer signaling pathways. In this review, we discuss the most recent findings on the role of O-GlcNAcylation as a metabolic sensor in signaling pathways and immune response in cancer.
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23
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Gonzalez-Rellan MJ, Fondevila MF, Dieguez C, Nogueiras R. O-GlcNAcylation: A Sweet Hub in the Regulation of Glucose Metabolism in Health and Disease. Front Endocrinol (Lausanne) 2022; 13:873513. [PMID: 35527999 PMCID: PMC9072661 DOI: 10.3389/fendo.2022.873513] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 03/23/2022] [Indexed: 12/17/2022] Open
Abstract
O-GlcNAcylation is a posttranslational modification ruled by the activity of a single pair of enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). These two enzymes carry out the dynamic cycling of O-GlcNAcylation on a wide range of cytosolic, nuclear, and mitochondrial proteins in a nutrient- and stress-responsive manner. To maintain proper glucose homeostasis, a precise mechanism to sense blood glucose levels is required, to adapt cell physiology to fluctuations in nutrient intake to maintain glycemia within a narrow range. Disruptions in glucose homeostasis generates metabolic syndrome and type 2 diabetes. In this review we will discuss and summarize emerging findings that points O-GlcNAcylation as a hub in the control of systemic glucose homeostasis, and its involvement in the generation of insulin resistance and type 2 diabetes.
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Affiliation(s)
- Maria J. Gonzalez-Rellan
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, Spain
- *Correspondence: Maria J. Gonzalez-Rellan, ; Marcos F. Fondevila,
| | - Marcos F. Fondevila
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
- *Correspondence: Maria J. Gonzalez-Rellan, ; Marcos F. Fondevila,
| | - Carlos Dieguez
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| | - Ruben Nogueiras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
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24
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He X, Sun J, Liu C, Yu X, Li H, Zhang W, Li Y, Geng Y, Wang Z. Compositional Alterations of Gut Microbiota in Patients with Diabetic Kidney Disease and Type 2 Diabetes Mellitus. Diabetes Metab Syndr Obes 2022; 15:755-765. [PMID: 35280499 PMCID: PMC8911313 DOI: 10.2147/dmso.s347805] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 02/25/2022] [Indexed: 12/21/2022] Open
Abstract
PURPOSE Emerging evidence has revealed that gut microbiota plays a pivotal role in the pathogenesis of type 2 diabetes mellitus (T2DM) and diabetic kidney disease (DKD). However, few studies have used metagenomic sequencing to analyze the alterations of gut microbiota community in patients with early-stage DKD. METHODS We carried out metagenomic sequencing in fecal samples of 10 DKD patients (DKD group) and 10 T2DM patients who appeared to be less prone to DKD (non-DKD group), aiming to compare the composition and function of gut microbiota between the DKD and non-DKD groups. RESULTS The gut microbial community of the DKD group was significantly different from that of the non-DKD group, characterized by a marked increase in phylum Proteobacteria, genus Selenomonadales, Neosynechococcus, Shigella, Bilophila, Acidaminococcus, species, Escherichia coli, Bacteroides plebeius, Megasphaera elsdenii, Acidaminococcus unclassified, and Bilophila wadsworthia. The amounts of species Citrobacter farmeri and Syntrophaceticus schinkii were significantly and positively correlated with the urinary albumin creatinine ratio in the DKD group. Furthermore, functional analysis based on dbCAN and KEGG databases showed aberrant lipopolysaccharide (LPS) biosynthesis and carbohydrate metabolism in the gut microbiome of the DKD group. CONCLUSION Our findings provided evidence for alterations in the composition and function of gut microbiota in patients with DKD versus the non-DKD group. These data may contribute to a more comprehensive understanding of the pathological mechanisms of DKD.
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Affiliation(s)
- Xin He
- Dialysis Department of Nephrology Hospital, First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, 710061, People’s Republic of China
| | - Jiping Sun
- Department of Nephrology, First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, 710061, People’s Republic of China
| | - Chao Liu
- Department of Nephrology, First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, 710061, People’s Republic of China
| | - Xiaoyang Yu
- Department of Nephrology, First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, 710061, People’s Republic of China
| | - Huixian Li
- Department of Nephrology, First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, 710061, People’s Republic of China
| | - Wenjing Zhang
- Department of Nephrology, First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, 710061, People’s Republic of China
| | - Yan Li
- Department of Nephrology, First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, 710061, People’s Republic of China
| | - Yingzhou Geng
- Department of Nephrology, First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, 710061, People’s Republic of China
| | - Zhigang Wang
- Department of Nephrology, First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, 710061, People’s Republic of China
- Correspondence: Zhigang Wang, First Affiliated Hospital of Xi’an Jiaotong University, West Yanta Road 277, Xi’an, 710061, People’s Republic of China, Email
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25
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Mohan R, Jo S, Lockridge A, Ferrington DA, Murray K, Eschenlauer A, Bernal-Mizrachi E, Fujitani Y, Alejandro EU. OGT Regulates Mitochondrial Biogenesis and Function via Diabetes Susceptibility Gene Pdx1. Diabetes 2021; 70:2608-2625. [PMID: 34462257 PMCID: PMC8564412 DOI: 10.2337/db21-0468] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 08/19/2021] [Indexed: 12/26/2022]
Abstract
O-GlcNAc transferase (OGT), a nutrient sensor sensitive to glucose flux, is highly expressed in the pancreas. However, the role of OGT in the mitochondria of β-cells is unexplored. In this study, we identified the role of OGT in mitochondrial function in β-cells. Constitutive deletion of OGT (βOGTKO) or inducible ablation in mature β-cells (iβOGTKO) causes distinct effects on mitochondrial morphology and function. Islets from βOGTKO, but not iβOGTKO, mice display swollen mitochondria, reduced glucose-stimulated oxygen consumption rate, ATP production, and glycolysis. Alleviating endoplasmic reticulum stress by genetic deletion of Chop did not rescue the mitochondrial dysfunction in βOGTKO mice. We identified altered islet proteome between βOGTKO and iβOGTKO mice. Pancreatic and duodenal homeobox 1 (Pdx1) was reduced in in βOGTKO islets. Pdx1 overexpression increased insulin content and improved mitochondrial morphology and function in βOGTKO islets. These data underscore the essential role of OGT in regulating β-cell mitochondrial morphology and bioenergetics. In conclusion, OGT couples nutrient signal and mitochondrial function to promote normal β-cell physiology.
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Affiliation(s)
- Ramkumar Mohan
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN
| | - Seokwon Jo
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN
| | - Amber Lockridge
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN
| | - Deborah A Ferrington
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota Medical School, Minneapolis, MN
| | - Kevin Murray
- University of Minnesota Informatics Institute, University of Minnesota Medical School, Minneapolis, MN
| | - Arthur Eschenlauer
- University of Minnesota Informatics Institute, University of Minnesota Medical School, Minneapolis, MN
| | - Ernesto Bernal-Mizrachi
- Miami VA Healthcare System, Miami, FL
- Division of Endocrinology, Diabetes and Metabolism, University of Miami, Miami, FL
| | - Yoshio Fujitani
- Institute for Molecular and Cellular Regulation, Gunma University, Gunma, Japan
| | - Emilyn U Alejandro
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN
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26
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Pancreatic β-Cell O-GlcNAc Transferase Overexpression Increases Susceptibility to Metabolic Stressors in Female Mice. Cells 2021; 10:cells10102801. [PMID: 34685781 PMCID: PMC8534823 DOI: 10.3390/cells10102801] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 10/14/2021] [Accepted: 10/14/2021] [Indexed: 01/21/2023] Open
Abstract
The nutrient-sensor O-GlcNAc transferase (Ogt), the sole enzyme that adds an O-GlcNAc-modification onto proteins, plays a critical role for pancreatic β-cell survival and insulin secretion. We hypothesized that β-cell Ogt overexpression would confer protection from β-cell failure in response to metabolic stressors, such as high-fat diet (HFD) and streptozocin (STZ). Here, we generated a β-cell-specific Ogt in overexpressing (βOgtOE) mice, where a significant increase in Ogt protein level and O-GlcNAc-modification of proteins were observed in islets under a normal chow diet. We uncovered that βOgtOE mice show normal peripheral insulin sensitivity and glucose tolerance with a regular chow diet. However, when challenged with an HFD, only female βOgtOE (homozygous) Hz mice developed a mild glucose intolerance, despite increased insulin secretion and normal β-cell mass. While female mice are normally resistant to low-dose STZ treatments, the βOgtOE Hz mice developed hyperglycemia and glucose intolerance post-STZ treatment. Transcriptome analysis between islets with loss or gain of Ogt by RNA sequencing shows common altered pathways involving pro-survival Erk and Akt and inflammatory regulators IL1β and NFkβ. Together, these data show a possible gene dosage effect of Ogt and the importance O-GlcNAc cycling in β-cell survival and function to regulate glucose homeostasis.
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27
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Lockridge A, Jo S, Gustafson E, Damberg N, Mohan R, Olson M, Abrahante JE, Alejandro EU. Islet O-GlcNAcylation Is Required for Lipid Potentiation of Insulin Secretion through SERCA2. Cell Rep 2021; 31:107609. [PMID: 32375037 DOI: 10.1016/j.celrep.2020.107609] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 01/24/2020] [Accepted: 04/12/2020] [Indexed: 12/19/2022] Open
Abstract
During early obesity, pancreatic β cells compensate for increased metabolic demand through a transient phase of insulin hypersecretion that stabilizes blood glucose and forestalls diabetic progression. We find evidence that β cell O-GlcNAcylation, a nutrient-responsive post-translational protein modification regulated by O-GlcNAc transferase (OGT), is critical for coupling hyperlipidemia to β cell functional adaptation during this compensatory prediabetic phase. In mice, islet O-GlcNAcylation rises and falls in tandem with the timeline of secretory potentiation during high-fat feeding while genetic models of β-cell-specific OGT loss abolish hyperinsulinemic responses to lipids, in vivo and in vitro. We identify the endoplasmic reticulum (ER) Ca2+ ATPase SERCA2 as a β cell O-GlcNAcylated protein in mice and humans that is able to rescue palmitate-stimulated insulin secretion through pharmacological activation. This study reveals an important physiological role for β cell O-GlcNAcylation in sensing and responding to obesity, with therapeutic implications for managing the relationship between type 2 diabetes and its most common risk factor.
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Affiliation(s)
- Amber Lockridge
- Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Seokwon Jo
- Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Eric Gustafson
- Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Niklas Damberg
- Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Ramkumar Mohan
- Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Miranda Olson
- Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Juan E Abrahante
- Supercomputing Institute, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Emilyn U Alejandro
- Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN, USA.
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28
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Hong H, Xu Y, Xu J, Zhang J, Xi Y, Pi H, Yang L, Yu Z, Wu Q, Meng Z, Ruan WS, Ren Y, Xu S, Lu YQ, Zhou Z. Cadmium exposure impairs pancreatic β-cell function and exaggerates diabetes by disrupting lipid metabolism. ENVIRONMENT INTERNATIONAL 2021; 149:106406. [PMID: 33508533 DOI: 10.1016/j.envint.2021.106406] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 12/23/2020] [Accepted: 01/13/2021] [Indexed: 06/12/2023]
Abstract
Cadmium is known as an environmental pollutant that contributes to pancreatic damage and the pathogenesis of diabetes. However, less attention has been devoted to elucidating the mechanisms underlying Cd-induced pancreatic β-cell dysfunction and the role of Cd toxicity in the development of diabetes. In this study, we demonstrated that exposure to Cd caused remarkable pancreatic β-cell dysfunction and death, both in vitro and in vivo. Lipidomic analysis of Cd-exposed pancreatic β-cells using high-resolution mass spectrometry revealed that Cd exposure altered the profile and abundance of lipids. Cd exposure induced intracellular lipid accumulation, promoted lipid biogenesis, elevated pro-inflammatory lipid contents and inhibited lipid degradation. Furthermore, Cd exposure upregulated the expression levels of TNF-α, IL-1β and IL-6 in pancreatic β-cells and elevated the TNF-α, IL1-β and IL-6 levels in the serum and pancreas. Taken together, the results of our study demonstrated that environmental relevant Cd exposure causes pro-inflammatory lipids elevation and insulin secretion dysfunction in β-cells and hence exaggerates diabetes development. Combined exposure to environmental hazardous chemicals might markedly increase the probability of developing diabetes in humans. This study provides new metabolic and pharmacological targets for antagonizing Cd toxicity.
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Affiliation(s)
- Huihui Hong
- Department of Environmental Medicine, and Department of Emergency Medicine of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yudong Xu
- Department of Environmental Medicine, and Department of Emergency Medicine of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jia Xu
- Department of Emergency Medicine, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China; Zhejiang Provincial Key Laboratory for Diagnosis and Treatment of Aging and Physic-chemical Injury Diseases, Hangzhou, China
| | - Jingjing Zhang
- Department of Environmental Medicine, and Department of Emergency Medicine of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yu Xi
- Department of Environmental Medicine, and Department of Emergency Medicine of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Huifeng Pi
- Department of Occupational Health, Third Military Medical University, Chongqing, China
| | - Lingling Yang
- Department of Occupational Health, Third Military Medical University, Chongqing, China
| | - Zhengping Yu
- Department of Occupational Health, Third Military Medical University, Chongqing, China
| | - Qingqian Wu
- Department of Pathology and Pathophysiology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Zhuoxian Meng
- Department of Pathology and Pathophysiology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Wei-Shuyi Ruan
- Department of Emergency Medicine, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China; Zhejiang Provincial Key Laboratory for Diagnosis and Treatment of Aging and Physic-chemical Injury Diseases, Hangzhou, China
| | - Yunzhao Ren
- Department of Environmental Medicine, and Department of Emergency Medicine of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Shuzhen Xu
- Department of Environmental Medicine, and Department of Emergency Medicine of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yuan-Qiang Lu
- Department of Emergency Medicine, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China; Zhejiang Provincial Key Laboratory for Diagnosis and Treatment of Aging and Physic-chemical Injury Diseases, Hangzhou, China.
| | - Zhou Zhou
- Department of Environmental Medicine, and Department of Emergency Medicine of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
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29
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Zhao M, Ren K, Xiong X, Cheng M, Zhang Z, Huang Z, Han X, Yang X, Alejandro EU, Ruan HB. Protein O-GlcNAc Modification Links Dietary and Gut Microbial Cues to the Differentiation of Enteroendocrine L Cells. Cell Rep 2021; 32:108013. [PMID: 32783937 PMCID: PMC7457433 DOI: 10.1016/j.celrep.2020.108013] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 06/16/2020] [Accepted: 07/17/2020] [Indexed: 02/08/2023] Open
Abstract
Intestinal L cells regulate a wide range of metabolic processes, and L-cell dysfunction has been implicated in the pathogenesis of obesity and diabetes. However, it is incompletely understood how luminal signals are integrated to control the development of L cells. Here we show that food availability and gut microbiota-produced short-chain fatty acids control the posttranslational modification on intracellular proteins by O-linked β-N-acetylglucosamine (O-GlcNAc) in intestinal epithelial cells. Via FOXO1 O-GlcNAcylation, O-GlcNAc transferase (OGT) suppresses expression of the lineage-specifying transcription factor Neurogenin 3 and, thus, L cell differentiation from enteroendocrine progenitors. Intestinal epithelial ablation of OGT in mice not only causes L cell hyperplasia and increased secretion of glucagon-like peptide 1 (GLP-1) but also disrupts gut microbial compositions, which notably contributes to decreased weight gain and improved glycemic control. Our results identify intestinal epithelial O-GlcNAc signaling as a brake on L cell development and function in response to nutritional and microbial cues. Zhao et al. identify OGT in intestinal epithelial cells as a “molecular brake” on L cell development and function in response to nutritional and microbial cues. OGT inhibits Ngn3 gene transcription and enteroendocrine differentiation via FOXO1 O-GlcNAcylation. Microbiota-derived SCFAs drive epithelial O-GlcNAcylation, which further influences gut microbiota to control systemic metabolism.
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Affiliation(s)
- Ming Zhao
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Kaiqun Ren
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA; College of Medicine, Hunan Normal University, Changsha, Hunan 410013, China
| | - Xiwen Xiong
- School of Forensic Medicine, Xinxiang Medical University, Xinxiang, Henan 453003, China
| | - Meng Cheng
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Zengdi Zhang
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Zan Huang
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Xiaonan Han
- Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Xiaoyong Yang
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06519, USA; Program in Integrative Cell Signaling and Neurobiology of Metabolism, Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06519, USA
| | - Emilyn U Alejandro
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Hai-Bin Ruan
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA; Center for Immunology, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
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30
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Morino K, Maegawa H. Role of O-linked N-acetylglucosamine in the homeostasis of metabolic organs, and its potential links with diabetes and its complications. J Diabetes Investig 2021; 12:130-136. [PMID: 32654398 PMCID: PMC7858115 DOI: 10.1111/jdi.13359] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/07/2020] [Accepted: 07/09/2020] [Indexed: 12/12/2022] Open
Abstract
Recent studies using genetically manipulated mouse models have shown the pivotal role of O-linked N-acetylglucosamine modification (O-GlcNAcylation) in the metabolism of multiple organs. The molecular mechanism involves the sensing of glucose flux by the hexosamine biosynthesis pathway, which leads to the adjustment of cellular metabolism to protect against changes in the environment of each organ through O-GlcNAcylation. More recently, not only glucose, but also fluxes of amino acids and fatty acids have been reported to induce O-GlcNAcylation, affecting multiple cellular processes. In this review, we discuss how O-GlcNAcylation maintains homeostasis in organs that are affected by diabetes mellitus: skeletal muscle, adipose tissue, liver and pancreatic β-cells. Furthermore, we discuss the importance of O-GlcNAcylation in the pathogenesis of diabetic complications. By elucidating the molecular mechanisms whereby cellular homeostasis is maintained, despite changes in metabolic flux, these studies might provide new targets for the treatment and prevention of diabetes and its complications.
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Affiliation(s)
- Katsutaro Morino
- Division of Diabetology, Endocrinology, and NephrologyDepartment of MedicineShiga University of Medical ScienceOtsuShigaJapan
| | - Hiroshi Maegawa
- Division of Diabetology, Endocrinology, and NephrologyDepartment of MedicineShiga University of Medical ScienceOtsuShigaJapan
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31
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Itkonen HM, Loda M, Mills IG. O-GlcNAc Transferase - An Auxiliary Factor or a Full-blown Oncogene? Mol Cancer Res 2021; 19:555-564. [PMID: 33472950 DOI: 10.1158/1541-7786.mcr-20-0926] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 12/05/2020] [Accepted: 01/07/2021] [Indexed: 11/16/2022]
Abstract
The β-linked N-acetyl-d-glucosamine (GlcNAc) is a posttranslational modification of serine and threonine residues catalyzed by the enzyme O-GlcNAc transferase (OGT). Increased OGT expression is a feature of most human cancers and inhibition of OGT decreases cancer cell proliferation. Antiproliferative effects are attributed to posttranslational modifications of known regulators of cancer cell proliferation, such as MYC, FOXM1, and EZH2. In general, OGT amplifies cell-specific phenotype, for example, OGT overexpression enhances reprogramming efficiency of mouse embryonic fibroblasts into stem cells. Genome-wide screens suggest that certain cancers are particularly dependent on OGT, and understanding these addictions is important when considering OGT as a target for cancer therapy. The O-GlcNAc modification is involved in most cellular processes, which raises concerns of on-target undesirable effects of OGT-targeting therapy. Yet, emerging evidence suggest that, much like proteasome inhibitors, specific compounds targeting OGT elicit selective antiproliferative effects in cancer cells, and can prime malignant cells to other treatments. It is, therefore, essential to gain mechanistic insights on substrate specificity for OGT, develop reagents to more specifically enrich for O-GlcNAc-modified proteins, identify O-GlcNAc "readers," and develop OGT small-molecule inhibitors. Here, we review the relevance of OGT in cancer progression and the potential targeting of this metabolic enzyme as a putative oncogene.
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Affiliation(s)
- Harri M Itkonen
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
| | - Massimo Loda
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York-Presbyterian Hospital, New York, New York.,The Broad Institute of Harvard and MIT, Cambridge, Massachusetts.,The New York Genome Center, New York, New York
| | - Ian G Mills
- Nuffield Department of Surgical Sciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom. .,PCUK/Movember Centre of Excellence for Prostate Cancer Research, Patrick G Johnston Centre, for Cancer Research (PGJCCR), Queen's University Belfast, Belfast, United Kingdom
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32
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Essawy A, Jo S, Beetch M, Lockridge A, Gustafson E, Alejandro EU. O-linked N-acetylglucosamine transferase (OGT) regulates pancreatic α-cell function in mice. J Biol Chem 2021; 296:100297. [PMID: 33460647 PMCID: PMC7949098 DOI: 10.1016/j.jbc.2021.100297] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 01/05/2021] [Accepted: 01/12/2021] [Indexed: 01/06/2023] Open
Abstract
The nutrient sensor O-GlcNAc transferase (OGT) catalyzes posttranslational addition of O-GlcNAc onto target proteins, influencing signaling pathways in response to cellular nutrient levels. OGT is highly expressed in pancreatic glucagon-secreting cells (α-cells), which secrete glucagon in response to hypoglycemia. The objective of this study was to determine whether OGT is necessary for the regulation of α-cell mass and function in vivo. We utilized genetic manipulation to produce two α-cell specific OGT-knockout models: a constitutive glucagon-Cre (αOGTKO) and an inducible glucagon-Cre (i-αOGTKO), which effectively delete OGT in α-cells. Using approaches including immunoblotting, immunofluorescent imaging, and metabolic phenotyping in vivo, we provide the first insight on the role of O-GlcNAcylation in α-cell mass and function. αOGTKO mice demonstrated normal glucose tolerance and insulin sensitivity but displayed significantly lower glucagon levels during both fed and fasted states. αOGTKO mice exhibited significantly lower α-cell glucagon content and α-cell mass at 6 months of age. In fasting, αOGTKO mice showed impaired pyruvate stimulated gluconeogenesis in vivo and reduced glucagon secretion in vitro. i-αOGTKO mice showed similarly reduced blood glucagon levels, defective in vitro glucagon secretion, and normal α-cell mass. Interestingly, both αOGTKO and i-αOGTKO mice had no deficiency in maintaining blood glucose homeostasis under fed or fasting conditions, despite impairment in α-cell mass and function, and glucagon content. In conclusion, these studies provide a first look at the role of OGT signaling in the α-cell, its effect on α-cell mass, and its importance in regulating glucagon secretion in hypoglycemic conditions.
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Affiliation(s)
- Ahmad Essawy
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Seokwon Jo
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Megan Beetch
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Amber Lockridge
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Eric Gustafson
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Emilyn U Alejandro
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN, USA.
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33
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Lockridge A, Gustafson E, Wong A, Miller RF, Alejandro EU. Acute D-Serine Co-Agonism of β-Cell NMDA Receptors Potentiates Glucose-Stimulated Insulin Secretion and Excitatory β-Cell Membrane Activity. Cells 2021; 10:E93. [PMID: 33430405 PMCID: PMC7826616 DOI: 10.3390/cells10010093] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 12/18/2020] [Accepted: 01/04/2021] [Indexed: 02/06/2023] Open
Abstract
Insulin-secreting pancreatic β-cells express proteins characteristic of D-serine regulated synapses, but the acute effect of D-serine co-agonism on its presumptive β-cell target, N-methyl D-aspartate receptors (NMDARs), is unclear. We used multiple models to evaluate glucose homeostasis and insulin secretion in mice with a systemic increase in D-serine (intraperitoneal injection or DAAO mutants without D-serine catabolism) or tissue-specific loss of Grin1-encoded GluN1, the D-serine binding NMDAR subunit. We also investigated the effects of D-serine ± NMDA on glucose-stimulated insulin secretion (GSIS) and β-cell depolarizing membrane oscillations, using perforated patch electrophysiology, in β-cell-containing primary isolated mouse islets. In vivo models of elevated D-serine correlated to improved blood glucose and insulin levels. In vitro, D-serine potentiated GSIS and β-cell membrane excitation, dependent on NMDAR activating conditions including GluN1 expression (co-agonist target), simultaneous NMDA (agonist), and elevated glucose (depolarization). Pancreatic GluN1-loss females were glucose intolerant and GSIS was depressed in islets from younger, but not older, βGrin1 KO mice. Thus, D-serine is capable of acute antidiabetic effects in mice and potentiates insulin secretion through excitatory β-cell NMDAR co-agonism but strain-dependent shifts in potency and age/sex-specific Grin1-loss phenotypes suggest that context is critical to the interpretation of data on the role of D-serine and NMDARs in β-cell function.
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Affiliation(s)
- Amber Lockridge
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN 55455, USA; (A.L.); (E.G.); (A.W.)
| | - Eric Gustafson
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN 55455, USA; (A.L.); (E.G.); (A.W.)
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA;
| | - Alicia Wong
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN 55455, USA; (A.L.); (E.G.); (A.W.)
| | - Robert F. Miller
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA;
| | - Emilyn U. Alejandro
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN 55455, USA; (A.L.); (E.G.); (A.W.)
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34
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Jo S, Lockridge A, Mohan R, Esch N, Schlichting R, Panigrahy N, Essawy A, Gustafson E, Alejandro EU. Translational Factor eIF4G1 Regulates Glucose Homeostasis and Pancreatic β-Cell Function. Diabetes 2021; 70:155-170. [PMID: 33115825 PMCID: PMC7881850 DOI: 10.2337/db20-0057] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 10/18/2020] [Indexed: 12/27/2022]
Abstract
Protein translation is essential for cell physiology, and dysregulation of this process has been linked to aging-related diseases such as type 2 diabetes. Reduced protein level of a requisite scaffolding protein of the initiation complex, eIF4G1, downstream of nutrients and insulin signaling is associated with diabetes in humans and mice. In the current study, we tested the hypothesis that eIF4G1 is critical for β-cell function and glucose homeostasis by genetically ablating eIF4G1 specifically in β-cells in vivo (βeIF4G1 knockout [KO]). Adult male and female βeIF4G1KO mice displayed glucose intolerance but normal insulin sensitivity. β-Cell mass was normal under steady state and under metabolic stress by diet-induced obesity, but we observed increases in proliferation and apoptosis in β-cells of βeIF4G1KO. We uncovered deficits in insulin secretion, partly due to reduced mitochondrial oxygen consumption rate, glucose-stimulated Ca2+ flux, and reduced insulin content associated with loss of eIF4E, the mRNA 5' cap-binding protein of the initiation complex and binding partner of eIF4G1. Genetic reconstitution of eIF4E in single β-cells or intact islets of βeIF4G1KO mice recovers insulin content, implicating an unexplored role for eIF4G1/eIF4E in insulin biosynthesis. Altogether these data demonstrate an essential role for the translational factor eIF4G1 on glucose homeostasis and β-cell function.
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Affiliation(s)
- Seokwon Jo
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN
| | - Amber Lockridge
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN
| | - Ramkumar Mohan
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN
| | - Nicholas Esch
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN
| | - Regina Schlichting
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN
| | - Neha Panigrahy
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN
| | - Ahmad Essawy
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN
| | - Eric Gustafson
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN
| | - Emilyn U Alejandro
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN
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Mizukami H, Osonoi S, Takaku S, Yamagishi SI, Ogasawara S, Sango K, Chung S, Yagihashi S. Role of glucosamine in development of diabetic neuropathy independent of the aldose reductase pathway. Brain Commun 2020; 2:fcaa168. [PMID: 33305258 PMCID: PMC7713992 DOI: 10.1093/braincomms/fcaa168] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 08/04/2020] [Accepted: 08/24/2020] [Indexed: 12/30/2022] Open
Abstract
Long-term metabolic aberrations contribute to the development of diabetic neuropathy but the precise mechanism or mechanisms remains elusive. We have previously shown that aldose reductase-deficient mice exhibit delayed onset and progression of neuropathy following induction of diabetes, suggesting a role both for downstream metabolites of this enzyme and also for other unrelated pathways. In this study, we have utilized comprehensive metabolomics analyses to identify potential neurotoxic metabolites in nerve of diabetic mice and explored the mechanism of peripheral nerve injury. Aldose reductase knockout and control C57Bl/6J mice were made diabetic by injection of streptozotocin and followed for 8–16 weeks. Diabetic aldose reductase knockout mice exhibited delayed onset of nerve conduction slowing compared to diabetic wild-type mice. The sciatic nerves from aldose reductase knockout mice exposed to 12 weeks of diabetes were used for metabolomics analysis and compared with analyses of nerves from age-matched diabetic wild-type mice as well as non-diabetic aldose reductase knockout and wild-type mice. Neurotoxicity of candidate metabolites was evaluated using cultured Schwann cells and dorsal root ganglion neurons, and further confirmed in vivo. Metabolomics analysis identified elevated glucosamine levels in both diabetic aldose reductase knockout and diabetic wild mice. Exposure to glucosamine reduced survival of cultured Schwann cells and neurons accompanied by increased expression of cleaved caspase 3, CCAT-enhancer-binding homologous protein and mitochondrial hexokinase-I, along with ATP depletion. These changes were suppressed by siRNA to hexokinase-I or the ATP donor, inosine, but not by the antioxidant N-acetylcysteine or the endoplasmic reticulum-stress inhibitor 4-phenylbutyrate. The O-GlcNAcylation enhancer, O-(2-acetamido-2-deoxy-d-glucopyranosylidene) amino N-phenylcarbamate, did not augment glucosamine neurotoxicity. Single dose glucosamine injection into mice caused a reduction of sciatic nerve Na, K-ATPase activity, ATP content and augmented expression of hexokinase-I, which were suppressed by pretreatment with inosine but not with 4-phenylbutyrate. Mice implanted with a subcutaneous pump to infuse glucosamine for 12 weeks developed nerve conduction slowing and intraepidermal nerve fibre loss, recapitulating prominent indices of diabetic neuropathy. While acute glucosamine neurotoxicity is unlikely to contribute substantially to the slowly developing neuropathy phenotype in humans, sustained energy deprivation induced by glucosamine may well contribute to the pathogenesis of diabetic neuropathy. Our data thus identifies a novel pathway for diabetic neuropathy that may offer a potential new therapeutic target.
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Affiliation(s)
- Hiroki Mizukami
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Sho Osonoi
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Shizuka Takaku
- Diabetic Neuropathy Project, Tokyo Metropolitan Institute of Medical Science, Tokyo
| | - Shin-Ichiro Yamagishi
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Saori Ogasawara
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Kazunori Sango
- Diabetic Neuropathy Project, Tokyo Metropolitan Institute of Medical Science, Tokyo
| | - Sookja Chung
- Faculty of Medicine, Macau University of Science and Technology, Taipa, Macau
| | - Soroku Yagihashi
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
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36
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Wang X, Lin Y, Liu S, Zhu Y, Lu K, Broering R, Lu M. O-GlcNAcylation modulates HBV replication through regulating cellular autophagy at multiple levels. FASEB J 2020; 34:14473-14489. [PMID: 32892442 DOI: 10.1096/fj.202001168rr] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 08/10/2020] [Accepted: 08/14/2020] [Indexed: 02/05/2023]
Abstract
O-GlcNAcylation is a form of posttranslational modification, and serves various functions, including modulation of location, stability, and activity for the modified proteins. O-linked-N-acetylglucosamine (O-GlcNAc) transferase (OGT) is an essential cellular enzyme that posttranslationally modifies the cellular proteins with O-GlcNAc moiety. Early studies reported that the decreased O-GlcNAcylation regulates cellular autophagy, a process relevant for hepatitis B virus replication (HBV) and assembly. Therefore, we addressed the question how O-GlcNAcylation regulates cellular autophagy and HBV replication. Inhibition of OGT activity with a small molecule inhibitor OSMI-1 or silencing OGT significantly enhanced HBV replication and HBsAg production in hepatoma cells and primary human hepatocytes (PHHs). Western blotting analysis showed that inhibition of O-GlcNAcylation-induced endoplasmic reticulum (ER) stress and cellular autophagy, two processes subsequently leading to enhanced HBV replication. Importantly, the numbers of autophagosomes and the levels of autophagic markers LC3-II and SQSTM1/p62 in hepatoma cells were elevated after inhibition of O-GlcNAcylation. Further analysis revealed that inhibition of O-GlcNAcylation blocked autophagosome-lysosome fusion and thereby prevented autophagic degradation of HBV virions and proteins. Moreover, OSMI-1 further promoted HBV replication by inducing autophagosome formation via inhibiting the O-GlcNAcylation of Akt and mTOR. In conclusion, decreased O-GlcNAcylation enhanced HBV replication through increasing autophagosome formation at multiple levels, including triggering ER-stress, Akt/mTOR inhibition, and blockade of autophagosome-lysosome fusion.
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Affiliation(s)
- Xueyu Wang
- Institute of Virology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Yong Lin
- Institute of Virology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.,Key Laboratory of Molecular Biology of Infectious Diseases (Chinese Ministry of Education), Chongqing Medical University, Chongqing, China
| | - Shi Liu
- Institute of Virology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.,State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Ying Zhu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Kefeng Lu
- Department of Neurosurgery, State Key Laboratory of Biotherapy, Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Ruth Broering
- Department of Gastroenterology and Hepatology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Mengji Lu
- Institute of Virology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
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37
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Baumann D, Wong A, Akhaphong B, Jo S, Pritchard S, Mohan R, Chung G, Zhang Y, Alejandro EU. Role of nutrient-driven O-GlcNAc-post-translational modification in pancreatic exocrine and endocrine islet development. Development 2020; 147:dev186643. [PMID: 32165492 PMCID: PMC7174839 DOI: 10.1242/dev.186643] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 02/25/2020] [Indexed: 12/16/2022]
Abstract
Although the developing pancreas is exquisitely sensitive to nutrient supply in utero, it is not entirely clear how nutrient-driven post-translational modification of proteins impacts the pancreas during development. We hypothesized that the nutrient-sensing enzyme O-GlcNAc transferase (Ogt), which catalyzes an O-GlcNAc-modification onto key target proteins, integrates nutrient-signaling networks to regulate cell survival and development. In this study, we investigated the heretofore unknown role of Ogt in exocrine and endocrine islet development. By genetic manipulation in vivo and by using morphometric and molecular analyses, such as immunofluorescence imaging and single cell RNA sequencing, we show the first evidence that Ogt regulates pancreas development. Genetic deletion of Ogt in the pancreatic epithelium (OgtKOPanc) causes pancreatic hypoplasia, in part by increased apoptosis and reduced levels of of Pdx1 protein. Transcriptomic analysis of single cell and bulk RNA sequencing uncovered cell-type heterogeneity and predicted upstream regulator proteins that mediate cell survival, including Pdx1, Ptf1a and p53, which are putative Ogt targets. In conclusion, these findings underscore the requirement of O-GlcNAcylation during pancreas development and show that Ogt is essential for pancreatic progenitor survival, providing a novel mechanistic link between nutrients and pancreas development.
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Affiliation(s)
- Daniel Baumann
- Department of Integrative Biology and Physiology, University of Minnesota Medical School. Minneapolis, MN 55455, USA
| | - Alicia Wong
- Department of Integrative Biology and Physiology, University of Minnesota Medical School. Minneapolis, MN 55455, USA
| | - Brian Akhaphong
- Department of Integrative Biology and Physiology, University of Minnesota Medical School. Minneapolis, MN 55455, USA
| | - Seokwon Jo
- Department of Integrative Biology and Physiology, University of Minnesota Medical School. Minneapolis, MN 55455, USA
| | - Samantha Pritchard
- Department of Integrative Biology and Physiology, University of Minnesota Medical School. Minneapolis, MN 55455, USA
| | - Ramkumar Mohan
- Department of Integrative Biology and Physiology, University of Minnesota Medical School. Minneapolis, MN 55455, USA
| | - Grace Chung
- Department of Integrative Biology and Physiology, University of Minnesota Medical School. Minneapolis, MN 55455, USA
| | - Ying Zhang
- Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455, USA
| | - Emilyn U Alejandro
- Department of Integrative Biology and Physiology, University of Minnesota Medical School. Minneapolis, MN 55455, USA
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38
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MUC1 oncoprotein mitigates ER stress via CDA-mediated reprogramming of pyrimidine metabolism. Oncogene 2020; 39:3381-3395. [PMID: 32103170 PMCID: PMC7165067 DOI: 10.1038/s41388-020-1225-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 02/12/2020] [Accepted: 02/14/2020] [Indexed: 12/12/2022]
Abstract
The Mucin 1 (MUC1) protein is overexpressed in various cancers and mediates chemotherapy resistance. However, the mechanism is not fully understood. Given that most chemotherapeutic drugs disrupt ER homeostasis as part of their toxicity, and MUC1 expression is regulated by proteins involved in ER homeostasis, we investigated the link between MUC1 and ER homeostasis. MUC1 knockdown in pancreatic cancer cells enhanced unfolded protein response (UPR) signaling and cell death upon ER stress induction. Transcriptomic analysis revealed alterations in the pyrimidine metabolic pathway and cytidine deaminase (CDA). ChIP and CDA activity assays showed that MUC1 occupied CDA gene promoter upon ER stress induction correlating with increased CDA expression and activity in MUC1-expressing cells as compared to MUC1 knockdown cells. Inhibition of either the CDA or pyrimidine metabolic pathway diminished survival in MUC1-expressing cancer cells upon ER stress induction. Metabolomic analysis demonstrated that MUC1-mediated CDA activity corresponded to deoxycytidine to deoxyuridine metabolic reprogramming upon ER stress induction. The resulting increase in deoxyuridine mitigated ER stress-induced cytotoxicity. Additionally, given 1) the established roles of MUC1 in protecting cells against reactive oxygen species (ROS) insults, 2) ER stress-generated ROS further promote ER stress and 3) the emerging anti-oxidant property of deoxyuridine, we further investigated if MUC1 regulated ER stress by a deoxyuridine-mediated modulation of ROS levels. We observed that deoxyuridine could abrogate ROS-induced ER stress to promote cancer cell survival. Taken together, our findings demonstrate a novel MUC1-CDA axis of the adaptive UPR that provides survival advantage upon ER stress induction.
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Esch N, Jo S, Moore M, Alejandro EU. Nutrient Sensor mTOR and OGT: Orchestrators of Organelle Homeostasis in Pancreatic β-Cells. J Diabetes Res 2020; 2020:8872639. [PMID: 33457426 PMCID: PMC7787834 DOI: 10.1155/2020/8872639] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/06/2020] [Accepted: 11/24/2020] [Indexed: 02/08/2023] Open
Abstract
The purpose of this review is to integrate the role of nutrient-sensing pathways into β-cell organelle dysfunction prompted by nutrient excess during type 2 diabetes (T2D). T2D encompasses chronic hyperglycemia, hyperlipidemia, and inflammation, which each contribute to β-cell failure. These factors can disrupt the function of critical β-cell organelles, namely, the ER, mitochondria, lysosomes, and autophagosomes. Dysfunctional organelles cause defects in insulin synthesis and secretion and activate apoptotic pathways if homeostasis is not restored. In this review, we will focus on mTORC1 and OGT, two major anabolic nutrient sensors with important roles in β-cell physiology. Though acute stimulation of these sensors frequently improves β-cell function and promotes adaptation to cell stress, chronic and sustained activity disturbs organelle homeostasis. mTORC1 and OGT regulate organelle function by influencing the expression and activities of key proteins, enzymes, and transcription factors, as well as by modulating autophagy to influence clearance of defective organelles. In addition, mTORC1 and OGT activity influence islet inflammation during T2D, which can further disrupt organelle and β-cell function. Therapies for T2D that fine-tune the activity of these nutrient sensors have yet to be developed, but the important role of mTORC1 and OGT in organelle homeostasis makes them promising targets to improve β-cell function and survival.
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Affiliation(s)
- Nicholas Esch
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, University of Minnesota, Minneapolis, Minnesota, USA
| | - Seokwon Jo
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, University of Minnesota, Minneapolis, Minnesota, USA
| | - Mackenzie Moore
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, University of Minnesota, Minneapolis, Minnesota, USA
- Department of Surgery, University of Minnesota Medical School, University of Minnesota, Minneapolis, Minnesota, USA
| | - Emilyn U. Alejandro
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, University of Minnesota, Minneapolis, Minnesota, USA
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40
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Jo S, Lockridge A, Alejandro EU. eIF4G1 and carboxypeptidase E axis dysregulation in O-GlcNAc transferase-deficient pancreatic β-cells contributes to hyperproinsulinemia in mice. J Biol Chem 2019; 294:13040-13050. [PMID: 31300553 DOI: 10.1074/jbc.ra119.008670] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 07/08/2019] [Indexed: 12/13/2022] Open
Abstract
An early hallmark of type 2 diabetes is a failure of proinsulin-to-insulin processing in pancreatic β-cells, resulting in hyperproinsulinemia. Proinsulin processing is quite sensitive to nutrient flux, and β-cell-specific deletion of the nutrient-sensing protein modifier OGlcNAc transferase (βOGTKO) causes β-cell failure and diabetes, including early development of hyperproinsulinemia. The mechanisms underlying this latter defect are unknown. Here, using several approaches, including site-directed mutagenesis, Click O-GlcNAc labeling, immunoblotting, and immunofluorescence and EM imaging, we provide the first evidence for a relationship between the O-GlcNAcylation of eukaryotic translation initiation factor 4γ1 (eIF4G1) and carboxypeptidase E (CPE)-dependent proinsulin processing in βOGTKO mice. We first established that βOGTKO hyperproinsulinemia is independent of age, sex, glucose levels, and endoplasmic reticulum-CCAAT enhancer-binding protein homologous protein (CHOP)-mediated stress status. Of note, OGT loss was associated with a reduction in β-cell-resident CPE, and genetic reconstitution of CPE in βOGTKO islets rescued the dysfunctional proinsulin-to-insulin ratio. We show that although CPE is not directly OGlcNAc modified in islets, overexpression of the suspected OGT target eIF4G1, previously shown to regulate CPE translation in β-cells, increases islet CPE levels, and fully reverses βOGTKO islet-induced hyperproinsulinemia. Furthermore, our results reveal that OGT O-GlcNAc-modifies eIF4G1 at Ser-61 and that this modification is critical for eIF4G1 protein stability. Together, these results indicate a direct link between nutrient-sensitive OGT and insulin processing, underscoring the importance of post-translational O-GlcNAc modification in general cell physiology.
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Affiliation(s)
- Seokwon Jo
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota 55455
| | - Amber Lockridge
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota 55455
| | - Emilyn U Alejandro
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota 55455.
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41
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Itkonen HM, Urbanucci A, Martin SES, Khan A, Mathelier A, Thiede B, Walker S, Mills IG. High OGT activity is essential for MYC-driven proliferation of prostate cancer cells. Am J Cancer Res 2019; 9:2183-2197. [PMID: 31149037 PMCID: PMC6531294 DOI: 10.7150/thno.30834] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Accepted: 02/18/2019] [Indexed: 01/01/2023] Open
Abstract
O-GlcNAc transferase (OGT) is overexpressed in aggressive prostate cancer. OGT modifies intra-cellular proteins via single sugar conjugation (O-GlcNAcylation) to alter their activity. We recently discovered the first fast-acting OGT inhibitor OSMI-2. Here, we probe the stability and function of the chromatin O-GlcNAc and identify transcription factors that coordinate with OGT to promote proliferation of prostate cancer cells. Methods: Chromatin immunoprecipitation (ChIP) coupled to sequencing (seq), formaldehyde-assisted isolation of regulatory elements, RNA-seq and reverse-phase protein arrays (RPPA) were used to study the importance of OGT for chromatin structure and transcription. Mass spectrometry, western blot, RT-qPCR, cell cycle analysis and viability assays were used to establish the role of OGT for MYC-related processes. Prostate cancer patient data profiled for both mRNA and protein levels were used to validate findings. Results: We show for the first time that OGT inhibition leads to a rapid loss of O-GlcNAc chromatin mark. O-GlcNAc ChIP-seq regions overlap with super-enhancers (SE) and MYC binding sites. OGT inhibition leads to down-regulation of SE-dependent genes. We establish the first O-GlcNAc chromatin consensus motif, which we use as a bait for mass spectrometry. By combining the proteomic data from oligonucleotide enrichment with O-GlcNAc and MYC ChIP-mass spectrometry, we identify host cell factor 1 (HCF-1) as an interaction partner of MYC. Inhibition of OGT disrupts this interaction and compromises MYC's ability to confer androgen-independent proliferation to prostate cancer cells. We show that OGT is required for MYC-mediated stabilization of mitotic proteins, including Cyclin B1, and/or the increased translation of their coding transcripts. This implies that increased expression of mRNA is not always required to achieve increased protein expression and confer aggressive phenotype. Indeed, high expression of Cyclin B1 protein has strong predictive value in prostate cancer patients (p=0.000014) while mRNA does not. Conclusions: OGT promotes SE-dependent gene expression. OGT activity is required for the interaction between MYC and HCF-1 and expression of MYC-regulated mitotic proteins. These features render OGT essential for the androgen-independent, MYC-driven proliferation of prostate cancer cells. Androgen-independency is the major mechanism of prostate cancer progression, and our study identifies OGT as an essential mediator in this process.
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Zachara NE. Critical observations that shaped our understanding of the function(s) of intracellular glycosylation (O-GlcNAc). FEBS Lett 2018; 592:3950-3975. [PMID: 30414174 DOI: 10.1002/1873-3468.13286] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 10/30/2018] [Accepted: 10/31/2018] [Indexed: 12/30/2022]
Abstract
Almost 100 years after the first descriptions of proteins conjugated to carbohydrates (mucins), several studies suggested that glycoproteins were not restricted to the serum, extracellular matrix, cell surface, or endomembrane system. In the 1980s, key data emerged demonstrating that intracellular proteins were modified by monosaccharides of O-linked β-N-acetylglucosamine (O-GlcNAc). Subsequently, this modification was identified on thousands of proteins that regulate cellular processes as diverse as protein aggregation, localization, post-translational modifications, activity, and interactions. In this Review, we will highlight critical discoveries that shaped our understanding of the molecular events underpinning the impact of O-GlcNAc on protein function, the role that O-GlcNAc plays in maintaining cellular homeostasis, and our understanding of the mechanisms that regulate O-GlcNAc-cycling.
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Affiliation(s)
- Natasha E Zachara
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Mattila J, Kokki K, Hietakangas V, Boutros M. Stem Cell Intrinsic Hexosamine Metabolism Regulates Intestinal Adaptation to Nutrient Content. Dev Cell 2018; 47:112-121.e3. [PMID: 30220570 PMCID: PMC6179903 DOI: 10.1016/j.devcel.2018.08.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 07/07/2018] [Accepted: 08/14/2018] [Indexed: 02/08/2023]
Abstract
The intestine is an organ with an exceptionally high rate of cell turnover, and perturbations in this process can lead to severe diseases such as cancer or intestinal atrophy. Nutrition has a profound impact on intestinal volume and cellular architecture. However, how intestinal homeostasis is maintained in fluctuating dietary conditions remains insufficiently understood. By utilizing the Drosophila midgut model, we reveal a novel stem cell intrinsic mechanism coupling cellular metabolism with stem cell extrinsic growth signal. Our results show that intestinal stem cells (ISCs) employ the hexosamine biosynthesis pathway (HBP) to monitor nutritional status. Elevated activity of HBP promotes Warburg effect-like metabolic reprogramming required for adjusting the ISC division rate according to nutrient content. Furthermore, HBP activity is an essential facilitator for insulin signaling-induced ISC proliferation. In conclusion, ISC intrinsic hexosamine synthesis regulates metabolic pathway activities and defines the stem cell responsiveness to niche-derived growth signals. HBP is a mediator of Drosophila midgut adaptation to nutrient content ISC intrinsic HBP is a necessary and sufficient driver of stem cell divisions HBP activity regulates a Warburg-like metabolic reprogramming of the intestine HBP activity determines the output of InR signaling of the ISCs
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Affiliation(s)
- Jaakko Mattila
- German Cancer Research Center, Division of Signaling and Functional Genomics and Heidelberg University, Heidelberg 69120, Germany
| | - Krista Kokki
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki 00790, Finland; Institute of Biotechnology, University of Helsinki, Helsinki 00790, Finland
| | - Ville Hietakangas
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki 00790, Finland; Institute of Biotechnology, University of Helsinki, Helsinki 00790, Finland
| | - Michael Boutros
- German Cancer Research Center, Division of Signaling and Functional Genomics and Heidelberg University, Heidelberg 69120, Germany.
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Liu C, Li J. O-GlcNAc: A Sweetheart of the Cell Cycle and DNA Damage Response. Front Endocrinol (Lausanne) 2018; 9:415. [PMID: 30105004 PMCID: PMC6077185 DOI: 10.3389/fendo.2018.00415] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 07/02/2018] [Indexed: 01/22/2023] Open
Abstract
The addition and removal of O-linked N-acetylglucosamine (O-GlcNAc) to and from the Ser and Thr residues of proteins is an emerging post-translational modification. Unlike phosphorylation, which requires a legion of kinases and phosphatases, O-GlcNAc is catalyzed by the sole enzyme in mammals, O-GlcNAc transferase (OGT), and reversed by the sole enzyme, O-GlcNAcase (OGA). With the advent of new technologies, identification of O-GlcNAcylated proteins, followed by pinpointing the modified residues and understanding the underlying molecular function of the modification has become the very heart of the O-GlcNAc biology. O-GlcNAc plays a multifaceted role during the unperturbed cell cycle, including regulating DNA replication, mitosis, and cytokinesis. When the cell cycle is challenged by DNA damage stresses, O-GlcNAc also protects genome integrity via modifying an array of histones, kinases as well as scaffold proteins. Here we will focus on both cell cycle progression and the DNA damage response, summarize what we have learned about the role of O-GlcNAc in these processes and envision a sweeter research future.
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Affiliation(s)
| | - Jing Li
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing, China
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45
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Regulation of Carbohydrate Energy Metabolism in Drosophila melanogaster. Genetics 2018; 207:1231-1253. [PMID: 29203701 DOI: 10.1534/genetics.117.199885] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 07/02/2017] [Indexed: 02/08/2023] Open
Abstract
Carbohydrate metabolism is essential for cellular energy balance as well as for the biosynthesis of new cellular building blocks. As animal nutrient intake displays temporal fluctuations and each cell type within the animal possesses specific metabolic needs, elaborate regulatory systems are needed to coordinate carbohydrate metabolism in time and space. Carbohydrate metabolism is regulated locally through gene regulatory networks and signaling pathways, which receive inputs from nutrient sensors as well as other pathways, such as developmental signals. Superimposed on cell-intrinsic control, hormonal signaling mediates intertissue information to maintain organismal homeostasis. Misregulation of carbohydrate metabolism is causative for many human diseases, such as diabetes and cancer. Recent work in Drosophila melanogaster has uncovered new regulators of carbohydrate metabolism and introduced novel physiological roles for previously known pathways. Moreover, genetically tractable Drosophila models to study carbohydrate metabolism-related human diseases have provided new insight into the mechanisms of pathogenesis. Due to the high degree of conservation of relevant regulatory pathways, as well as vast possibilities for the analysis of gene-nutrient interactions and tissue-specific gene function, Drosophila is emerging as an important model system for research on carbohydrate metabolism.
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46
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Very N, Vercoutter-Edouart AS, Lefebvre T, Hardivillé S, El Yazidi-Belkoura I. Cross-Dysregulation of O-GlcNAcylation and PI3K/AKT/mTOR Axis in Human Chronic Diseases. Front Endocrinol (Lausanne) 2018; 9:602. [PMID: 30356686 PMCID: PMC6189293 DOI: 10.3389/fendo.2018.00602] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 09/21/2018] [Indexed: 02/06/2023] Open
Abstract
The hexosamine biosynthetic pathway (HBP) and the phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling pathway are considered as nutrient sensors that regulate several essential biological processes. The hexosamine biosynthetic pathway produces uridine diphosphate N-acetylglucosamine (UDP-GlcNAc), the substrate for O-GlcNAc transferase (OGT), the enzyme that O-GlcNAcylates proteins on serine (Ser) and threonine (Thr) residues. O-linked β-N-acetylglucosaminylation (O-GlcNAcylation) and phosphorylation are highly dynamic post-translational modifications occurring at the same or adjacent sites that regulate folding, stability, subcellular localization, partner interaction, or activity of target proteins. Here we review recent evidence of a cross-regulation of PI3K/AKT/mTOR signaling pathway and protein O-GlcNAcylation. Furthermore, we discuss their co-dysregulation in pathological conditions, e.g., cancer, type-2 diabetes (T2D), and cardiovascular, and neurodegenerative diseases.
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47
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Ida S, Morino K, Sekine O, Ohashi N, Kume S, Chano T, Iwasaki K, Harada N, Inagaki N, Ugi S, Maegawa H. Diverse metabolic effects of O-GlcNAcylation in the pancreas but limited effects in insulin-sensitive organs in mice. Diabetologia 2017. [PMID: 28642969 DOI: 10.1007/s00125-017-4327-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
AIMS/HYPOTHESIS O-GlcNAcylation is characterised by the addition of N-acetylglucosamine to various proteins by O-GlcNAc transferase (OGT) and serves in sensing intracellular nutrients by modulating various cellular processes. Although it has been speculated that O-GlcNAcylation is associated with glucose metabolism, its exact role in whole body glucose metabolism has not been fully elucidated. Here, we investigated whether loss of O-GlcNAcylation globally and in specific organs affected glucose metabolism in mammals under physiological conditions. METHODS Tamoxifen-inducible global Ogt-knockout (Ogt-KO) mice were generated by crossbreeding Ogt-flox mice with R26-Cre-ERT2 mice. Liver, skeletal muscle, adipose tissue and pancreatic beta cell-specific Ogt-KO mice were generated by crossbreeding Ogt-flox mice with Alb-Cre, Mlc1f-Cre, Adipoq-Cre and Pdx1 PB-CreER™ mice, respectively. Glucose metabolism was evaluated by i.p. glucose and insulin tolerance tests. RESULTS Tamoxifen-inducible global Ogt-KO mice exhibited a lethal phenotype from 4 weeks post injection, suggesting that O-GlcNAcylation is essential for survival in adult mice. Tissue-specific Ogt deletion from insulin-sensitive organs, including liver, skeletal muscle and adipose tissue, had little impact on glucose metabolism under physiological conditions. However, pancreatic beta cell-specific Ogt-KO mice displayed transient hypoglycaemia (Ogt-flox 5.46 ± 0.41 vs Ogt-βKO 3.88 ± 0.26 mmol/l) associated with about twofold higher insulin secretion and accelerated adiposity, followed by subsequent hyperglycaemia (Ogt-flox 6.34 ± 0.32 vs Ogt-βKO 26.4 ± 2.37 mmol/l) with insulin depletion accompanied by beta cell apoptosis. CONCLUSIONS/INTERPRETATION These findings suggest that O-GlcNAcylation has little effect on glucose metabolism in insulin-sensitive tissues but plays a crucial role in pancreatic beta cell function and survival under physiological conditions. Our results provide novel insight into O-GlcNAc biology and physiology in glucose metabolism.
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Affiliation(s)
- Shogo Ida
- Department of Medicine, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan
| | - Katsutaro Morino
- Department of Medicine, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan.
| | - Osamu Sekine
- Department of Medicine, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan
| | - Natsuko Ohashi
- Department of Medicine, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan
| | - Shinji Kume
- Department of Medicine, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan
| | - Tokuhiro Chano
- Department of Clinical Laboratory Medicine, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Kanako Iwasaki
- Department of Diabetes, Endocrinology and Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Norio Harada
- Department of Diabetes, Endocrinology and Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Nobuya Inagaki
- Department of Diabetes, Endocrinology and Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Satoshi Ugi
- Department of Medicine, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan
| | - Hiroshi Maegawa
- Department of Medicine, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan
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48
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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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49
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Levine ZG, Walker S. The Biochemistry of O-GlcNAc Transferase: Which Functions Make It Essential in Mammalian Cells? Annu Rev Biochem 2017; 85:631-57. [PMID: 27294441 DOI: 10.1146/annurev-biochem-060713-035344] [Citation(s) in RCA: 143] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
O-linked N-acetylglucosamine transferase (OGT) is found in all metazoans and plays an important role in development but at the single-cell level is only essential in dividing mammalian cells. Postmitotic mammalian cells and cells of invertebrates such as Caenorhabditis elegans and Drosophila can survive without copies of OGT. Why OGT is required in dividing mammalian cells but not in other cells remains unknown. OGT has multiple biochemical activities. Beyond its well-known role in adding β-O-GlcNAc to serine and threonine residues of nuclear and cytoplasmic proteins, OGT also acts as a protease in the maturation of the cell cycle regulator host cell factor 1 (HCF-1) and serves as an integral member of several protein complexes, many of them linked to gene expression. In this review, we summarize current understanding of the mechanisms underlying OGT's biochemical activities and address whether known functions of OGT could be related to its essential role in dividing mammalian cells.
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Affiliation(s)
- Zebulon G Levine
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts 02115; ,
| | - Suzanne Walker
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts 02115; ,
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50
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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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