1
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Herstine JA, Chang PK, Chornyy S, Stevenson TJ, Sunshine AC, Nokhrina K, Rediger J, Wentz J, Vetter TA, Scholl E, Holaway C, Pyne NK, Bratasz A, Yeoh S, Flanigan KM, Bonkowsky JL, Bradbury AM. Evaluation of safety and early efficacy of AAV gene therapy in mouse models of vanishing white matter disease. Mol Ther 2024; 32:1701-1720. [PMID: 38549375 PMCID: PMC11184306 DOI: 10.1016/j.ymthe.2024.03.034] [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: 10/16/2023] [Revised: 02/13/2024] [Accepted: 03/26/2024] [Indexed: 04/15/2024] Open
Abstract
Leukoencephalopathy with vanishing white matter (VWM) is a progressive incurable white matter disease that most commonly occurs in childhood and presents with ataxia, spasticity, neurological degeneration, seizures, and premature death. A distinctive feature is episodes of rapid neurological deterioration provoked by stressors such as infection, seizures, or trauma. VWM is caused by autosomal recessive mutations in one of five genes that encode the eukaryotic initiation factor 2B complex, which is necessary for protein translation and regulation of the integrated stress response. The majority of mutations are in EIF2B5. Astrocytic dysfunction is central to pathophysiology, thereby constituting a potential therapeutic target. Herein we characterize two VWM murine models and investigate astrocyte-targeted adeno-associated virus serotype 9 (AAV9)-mediated EIF2B5 gene supplementation therapy as a therapeutic option for VWM. Our results demonstrate significant rescue in body weight, motor function, gait normalization, life extension, and finally, evidence that gene supplementation attenuates demyelination. Last, the greatest rescue results from a vector using a modified glial fibrillary acidic protein (GFAP) promoter-AAV9-gfaABC(1)D-EIF2B5-thereby supporting that astrocytic targeting is critical for disease correction. In conclusion, we demonstrate safety and early efficacy through treatment with a translatable astrocyte-targeted gene supplementation therapy for a disease that has no cure.
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Affiliation(s)
- Jessica A Herstine
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH 43215, USA; Department of Pediatrics, The Ohio State University, Columbus, OH 43210, USA; Center for Clinical and Translational Science, The Ohio State University, Columbus, OH 43210, USA
| | - Pi-Kai Chang
- Department of Pediatrics, The University of Utah School of Medicine, Salt Lake City, UT 84113, USA
| | - Sergiy Chornyy
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH 43215, USA
| | - Tamara J Stevenson
- Department of Pediatrics, The University of Utah School of Medicine, Salt Lake City, UT 84113, USA
| | - Alex C Sunshine
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH 43215, USA; Department of Neurology, Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Ksenia Nokhrina
- Department of Pediatrics, The University of Utah School of Medicine, Salt Lake City, UT 84113, USA
| | - Jessica Rediger
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH 43215, USA
| | - Julia Wentz
- Department of Pediatrics, The University of Utah School of Medicine, Salt Lake City, UT 84113, USA
| | - Tatyana A Vetter
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH 43215, USA; Department of Pediatrics, The Ohio State University, Columbus, OH 43210, USA
| | - Erika Scholl
- Department of Pediatrics, The University of Utah School of Medicine, Salt Lake City, UT 84113, USA
| | - Caleb Holaway
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH 43215, USA
| | - Nettie K Pyne
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH 43215, USA
| | - Anna Bratasz
- Small Animal Imaging Core, The Ohio State University, Columbus, OH 43210, USA
| | - Stewart Yeoh
- Preclinical Imaging Core, The University of Utah, Salt Lake City, UT 84112, USA
| | - Kevin M Flanigan
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH 43215, USA; Department of Pediatrics, The Ohio State University, Columbus, OH 43210, USA; Department of Neurology, The Ohio State University, Columbus, OH 43210, USA
| | - Joshua L Bonkowsky
- Department of Pediatrics, The University of Utah School of Medicine, Salt Lake City, UT 84113, USA; Center for Personalized Medicine, Primary Children's Hospital, Salt Lake City, UT 84113, USA.
| | - Allison M Bradbury
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH 43215, USA; Department of Pediatrics, The Ohio State University, Columbus, OH 43210, USA; Center for Clinical and Translational Science, The Ohio State University, Columbus, OH 43210, USA.
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2
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Mahé M, Rios-Fuller T, Katsara O, Schneider RJ. Non-canonical mRNA translation initiation in cell stress and cancer. NAR Cancer 2024; 6:zcae026. [PMID: 38828390 PMCID: PMC11140632 DOI: 10.1093/narcan/zcae026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 05/08/2024] [Accepted: 05/29/2024] [Indexed: 06/05/2024] Open
Abstract
The now well described canonical mRNA translation initiation mechanism of m7G 'cap' recognition by cap-binding protein eIF4E and assembly of the canonical pre-initiation complex consisting of scaffolding protein eIF4G and RNA helicase eIF4A has historically been thought to describe all cellular mRNA translation. However, the past decade has seen the discovery of alternative mechanisms to canonical eIF4E mediated mRNA translation initiation. Studies have shown that non-canonical alternate mechanisms of cellular mRNA translation initiation, whether cap-dependent or independent, serve to provide selective translation of mRNAs under cell physiological and pathological stress conditions. These conditions typically involve the global downregulation of canonical eIF4E1/cap-mediated mRNA translation, and selective translational reprogramming of the cell proteome, as occurs in tumor development and malignant progression. Cancer cells must be able to maintain physiological plasticity to acquire a migratory phenotype, invade tissues, metastasize, survive and adapt to severe microenvironmental stress conditions that involve inhibition of canonical mRNA translation initiation. In this review we describe the emerging, important role of non-canonical, alternate mechanisms of mRNA translation initiation in cancer, particularly in adaptation to stresses and the phenotypic cell fate changes involved in malignant progression and metastasis. These alternate translation initiation mechanisms provide new targets for oncology therapeutics development.
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Affiliation(s)
- Mélanie Mahé
- Department of Microbiology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Tiffany Rios-Fuller
- Department of Microbiology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Olga Katsara
- Department of Microbiology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Robert J Schneider
- Department of Microbiology, NYU Grossman School of Medicine, New York, NY 10016, USA
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3
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Madrazo N, Khattar Z, Powers ET, Rosarda JD, Wiseman RL. Mapping stress-responsive signaling pathways induced by mitochondrial proteostasis perturbations. Mol Biol Cell 2024; 35:ar74. [PMID: 38536439 PMCID: PMC11151107 DOI: 10.1091/mbc.e24-01-0041] [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: 01/30/2024] [Revised: 03/12/2024] [Accepted: 03/22/2024] [Indexed: 04/09/2024] Open
Abstract
Imbalances in mitochondrial proteostasis are associated with pathologic mitochondrial dysfunction implicated in etiologically diverse diseases. This has led to considerable interest in defining the mechanisms responsible for regulating mitochondria in response to mitochondrial stress. Numerous stress-responsive signaling pathways have been suggested to regulate mitochondria in response to proteotoxic stress. These include the integrated stress response (ISR), the heat shock response (HSR), and the oxidative stress response (OSR). Here, we define the stress signaling pathways activated in response to chronic mitochondrial proteostasis perturbations by monitoring the expression of sets of genes regulated downstream of each of these signaling pathways in published Perturb-seq datasets from K562 cells CRISPRi-depleted of mitochondrial proteostasis factors. Interestingly, we find that the ISR is preferentially activated in response to chronic, genetically-induced mitochondrial proteostasis stress, with no other pathway showing significant activation. Further, we demonstrate that CRISPRi depletion of other mitochondria-localized proteins similarly shows preferential activation of the ISR relative to other stress-responsive signaling pathways. These results both establish our gene set profiling approach as a viable strategy to probe stress responsive signaling pathways induced by perturbations to specific organelles and identify the ISR as the predominant stress-responsive signaling pathway activated in response to chronic disruption of mitochondrial proteostasis.
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Affiliation(s)
- Nicole Madrazo
- Department of Molecular and Cellular Biology, Scripps Research, La Jolla, CA 92037
| | - Zinia Khattar
- Department of Molecular and Cellular Biology, Scripps Research, La Jolla, CA 92037
- Del Norte High School, San Diego, CA 92127
| | - Evan T. Powers
- Department of Chemistry, Scripps Research, La Jolla, CA 92037
| | - Jessica D. Rosarda
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814
| | - R. Luke Wiseman
- Department of Molecular and Cellular Biology, Scripps Research, La Jolla, CA 92037
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4
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Daou F, Masante B, Gabetti S, Mochi F, Putame G, Zenobi E, Scatena E, Dell'Atti F, Favero F, Leigheb M, Del Gaudio C, Bignardi C, Massai D, Cochis A, Rimondini L. Unraveling the transcriptome profile of pulsed electromagnetic field stimulation in bone regeneration using a bioreactor-based investigation platform. Bone 2024; 182:117065. [PMID: 38428556 DOI: 10.1016/j.bone.2024.117065] [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: 11/27/2023] [Revised: 02/07/2024] [Accepted: 02/26/2024] [Indexed: 03/03/2024]
Abstract
INTRODUCTION Human mesenchymal stem cells (hMSCs) sense and respond to biomechanical and biophysical stimuli, yet the involved signaling pathways are not fully identified. The clinical application of biophysical stimulation including pulsed electromagnetic field (PEMF) has gained momentum in musculoskeletal disorders and bone tissue engineering. METHODOLOGY We herein aim to explore the role of PEMF stimulation in bone regeneration by developing trabecular bone-like tissues, and then, culturing them under bone-like mechanical stimulation in an automated perfusion bioreactor combined with a custom-made PEMF stimulator. After selecting the optimal cell seeding and culture conditions for inspecting the effects of PEMF on hMSCs, transcriptomic studies were performed on cells cultured under direct perfusion with and without PEMF stimulation. RESULTS We were able to identify a set of signaling pathways and upstream regulators associated with PEMF stimulation and to distinguish those linked to bone regeneration. Our findings suggest that PEMF induces the immune potential of hMSCs by activating and inhibiting various immune-related pathways, such as macrophage classical activation and MSP-RON signaling in macrophages, respectively, while promoting angiogenesis and osteogenesis, which mimics the dynamic interplay of biological processes during bone healing. CONCLUSIONS Overall, the adopted bioreactor-based investigation platform can be used to investigate the impact of PEMF stimulation on bone regeneration.
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Affiliation(s)
- Farah Daou
- Dept. of Health Sciences, Center for Translational Research on Autoimmune and Allergic Diseases (CAAD), Università del Piemonte Orientale (UPO), Novara, Italy
| | - Beatrice Masante
- Dept. of Mechanical and Aerospace Engineering, PolitoBIOMed Lab, Politecnico di Torino, Turin, Italy; Interuniversity Center for the Promotion of the 3Rs Principles in Teaching and Research, Pisa, Italy
| | - Stefano Gabetti
- Dept. of Mechanical and Aerospace Engineering, PolitoBIOMed Lab, Politecnico di Torino, Turin, Italy; Interuniversity Center for the Promotion of the 3Rs Principles in Teaching and Research, Pisa, Italy
| | | | - Giovanni Putame
- Dept. of Mechanical and Aerospace Engineering, PolitoBIOMed Lab, Politecnico di Torino, Turin, Italy; Interuniversity Center for the Promotion of the 3Rs Principles in Teaching and Research, Pisa, Italy
| | - Eleonora Zenobi
- Hypatia Research Consortium, Rome, Italy; E. Amaldi Foundation, Rome, Italy
| | - Elisa Scatena
- Hypatia Research Consortium, Rome, Italy; E. Amaldi Foundation, Rome, Italy
| | - Federica Dell'Atti
- Dept. of Health Sciences, Center for Translational Research on Autoimmune and Allergic Diseases (CAAD), Università del Piemonte Orientale (UPO), Novara, Italy
| | - Francesco Favero
- Dept. of Health Sciences, Center for Translational Research on Autoimmune and Allergic Diseases (CAAD), Università del Piemonte Orientale (UPO), Novara, Italy
| | - Massimiliano Leigheb
- Dept. of Health Sciences, Center for Translational Research on Autoimmune and Allergic Diseases (CAAD), Università del Piemonte Orientale (UPO), Novara, Italy; Department of Orthopaedics and Traumatology, "Maggiore della Carità" Hospital, Novara, Italy
| | | | - Cristina Bignardi
- Dept. of Mechanical and Aerospace Engineering, PolitoBIOMed Lab, Politecnico di Torino, Turin, Italy; Interuniversity Center for the Promotion of the 3Rs Principles in Teaching and Research, Pisa, Italy
| | - Diana Massai
- Dept. of Mechanical and Aerospace Engineering, PolitoBIOMed Lab, Politecnico di Torino, Turin, Italy; Interuniversity Center for the Promotion of the 3Rs Principles in Teaching and Research, Pisa, Italy
| | - Andrea Cochis
- Dept. of Health Sciences, Center for Translational Research on Autoimmune and Allergic Diseases (CAAD), Università del Piemonte Orientale (UPO), Novara, Italy
| | - Lia Rimondini
- Dept. of Health Sciences, Center for Translational Research on Autoimmune and Allergic Diseases (CAAD), Università del Piemonte Orientale (UPO), Novara, Italy.
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5
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Wagner PA, Song M, Ficner R, Kuhle B, Marintchev A. Molecular basis for the interactions of eIF2β with eIF5, eIF2B, and 5MP1 and their regulation by CK2. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.25.591181. [PMID: 38712236 PMCID: PMC11071521 DOI: 10.1101/2024.04.25.591181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
The heterotrimeric GTPase eukaryotic translation initiation factor 2 (eIF2) delivers the initiator Met-tRNAi to the ribosomal translation preinitiation complex. eIF2β has three lysine-rich repeats (K-boxes) in its N-terminal tail, which are important for binding to the GTPase-activating protein (GAP) eIF5, the guanine nucleotide exchange factor (GEF) eIF2B, and the regulator eIF5-mimic protein (5MP). Here, we combine X-ray crystallography with NMR to understand the molecular basis and dynamics of these interactions. The crystal structure of yeast eIF5-CTD in complex with K-box 3 of eIF2β reveals an extended binding site on eIF2β, far beyond the K-box. We show that human eIF5, eIF2Bε, and 5MP1 can all bind to each of the three K-boxes, while reducing each other's affinities. Moreover, all these affinities are increased by CK2 phosphomimetic mutations. Our results reveal how eIF5, eIF2B, and 5MP displace each other from eIF2, and elucidate the role of CK2 in remodeling the translation apparatus.
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6
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Madrazo N, Khattar Z, Powers ET, Rosarda JD, Wiseman RL. Mapping Stress-Responsive Signaling Pathways Induced by Mitochondrial Proteostasis Perturbations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.30.577830. [PMID: 38352575 PMCID: PMC10862789 DOI: 10.1101/2024.01.30.577830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Imbalances in mitochondrial proteostasis are associated with pathologic mitochondrial dysfunction implicated in etiologically-diverse diseases. This has led to considerable interest in defining the biological mechanisms responsible for regulating mitochondria in response to mitochondrial stress. Numerous stress responsive signaling pathways have been suggested to regulate mitochondria in response to proteotoxic stress, including the integrated stress response (ISR), the heat shock response (HSR), and the oxidative stress response (OSR). Here, we define the specific stress signaling pathways activated in response to mitochondrial proteostasis stress by monitoring the expression of sets of genes regulated downstream of each of these signaling pathways in published Perturb-seq datasets from K562 cells CRISPRi-depleted of individual mitochondrial proteostasis factors. Interestingly, we find that the ISR is preferentially activated in response to mitochondrial proteostasis stress, with no other pathway showing significant activation. Further expanding this study, we show that broad depletion of mitochondria-localized proteins similarly shows preferential activation of the ISR relative to other stress-responsive signaling pathways. These results both establish our gene set profiling approach as a viable strategy to probe stress responsive signaling pathways induced by perturbations to specific organelles and identify the ISR as the predominant stress-responsive signaling pathway activated in response to mitochondrial proteostasis disruption.
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Affiliation(s)
- Nicole Madrazo
- Department of Molecular and Cellular Biology, Scripps Research, La Jolla, CA 92037
- These authors contributed equally
| | - Zinia Khattar
- Department of Molecular and Cellular Biology, Scripps Research, La Jolla, CA 92037
- Del Norte High School, San Diego, CA 92127
- These authors contributed equally
| | - Evan T. Powers
- Department of Chemistry, Scripps Research, La Jolla, CA 92037
| | - Jessica D. Rosarda
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814
| | - R. Luke Wiseman
- Department of Molecular and Cellular Biology, Scripps Research, La Jolla, CA 92037
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7
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Ito T, Wuerth JD, Weber F. Protection of eIF2B from inhibitory phosphorylated eIF2: A viral strategy to maintain mRNA translation during the PKR-triggered integrated stress response. J Biol Chem 2023; 299:105287. [PMID: 37742919 PMCID: PMC10616414 DOI: 10.1016/j.jbc.2023.105287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 09/26/2023] Open
Abstract
The integrated stress response (ISR) protects cells from a variety of insults. Once elicited (e.g., by virus infections), it eventually leads to the block of mRNA translation. Central to the ISR are the interactions between translation initiation factors eIF2 and eIF2B. Under normal conditions, eIF2 drives the initiation of protein synthesis through hydrolysis of GTP, which becomes replenished by the guanine nucleotide exchange factor eIF2B. The antiviral branch of the ISR is activated by the RNA-activated kinase PKR which phosphorylates eIF2, thereby converting it into an eIF2B inhibitor. Here, we describe the recently solved structures of eIF2B in complex with eIF2 and a novel escape strategy used by viruses. While unphosphorylated eIF2 interacts with eIF2B in its "productive" conformation, phosphorylated eIF2 [eIF2(αP)] engages a different binding cavity on eIF2B and forces it into the "nonproductive" conformation that prohibits guanine nucleotide exchange factor activity. It is well established that viruses express so-called PKR antagonists that interfere with double-strand RNA, PKR itself, or eIF2. However recently, three taxonomically unrelated viruses were reported to encode antagonists targeting eIF2B instead. For one antagonist, the S segment nonstructural protein of Sandfly fever Sicilian virus, atomic structures showed that it occupies the eIF2(αP)-binding cavity on eIF2B without imposing a switch to the nonproductive conformation. S segment nonstructural protein thus antagonizes the activity of PKR by protecting eIF2B from inhibition by eIF2(αP). As the ISR and specifically eIF2B are central to neuroprotection and a wide range of genetic and age-related diseases, these developments may open new possibilities for treatments.
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Affiliation(s)
- Takuhiro Ito
- Laboratory for Translation Structural Biology, RIKEN Center for Biosystems Dynamics Research, Yokohama, Japan
| | | | - Friedemann Weber
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, Giessen, Germany.
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8
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Erdem M, Cicek M, Erson-Bensan AE. Versatile RNA: overlooked gems of the transcriptome. FEBS J 2023; 290:4843-4851. [PMID: 36719259 DOI: 10.1111/febs.16742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 01/16/2023] [Accepted: 01/30/2023] [Indexed: 02/01/2023]
Abstract
The critical role of RNA, its use and targetability concerning different aspects of human health are gaining more attention because our understanding of the versatility of RNA has dramatically evolved over the last decades. We now appreciate that RNA is far more critical than a messenger molecule and possesses many complicated functions. As a multifunctional molecule with its sequence, flexible structures and enzymatic abilities, RNA is genuinely powerful. Mammalian transcriptomes consist of a dynamically regulated plethora of coding and noncoding RNA types. However, some aspects of RNA metabolism remain to be explored. In this Viewpoint, we focus on the transcriptome's unconventional and possibly overlooked aspects to emphasize the importance of RNA in mammalian systems.
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Affiliation(s)
- Murat Erdem
- Department of Biological Sciences, Middle East Technical University, Ankara, Turkey
| | - Mustafa Cicek
- Department of Biology, Kamil Ozdag Faculty of Science, Karamanoglu Mehmetbey University, Karaman, Turkey
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9
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Gupta M, Walters B, Katsara O, Granados Blanco K, Geter P, Schneider R. eIF2Bδ blocks the integrated stress response and maintains eIF2B activity and cancer metastasis by overexpression in breast cancer stem cells. Proc Natl Acad Sci U S A 2023; 120:e2207898120. [PMID: 37014850 PMCID: PMC10104532 DOI: 10.1073/pnas.2207898120] [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: 05/06/2022] [Accepted: 03/08/2023] [Indexed: 04/05/2023] Open
Abstract
Breast cancer (BC) metastasis involves cancer stem cells (CSCs) and their regulation by micro-RNAs (miRs), but miR targeting of the translation machinery in CSCs is poorly explored. We therefore screened miR expression levels in a range of BC cell lines, comparing non-CSCs to CSCs, and focused on miRs that target translation and protein synthesis factors. We describe a unique translation regulatory axis enacted by reduced expression of miR-183 in breast CSCs, which we show targets the eIF2Bδ subunit of guanine nucleotide exchange factor eIF2B, a regulator of protein synthesis and the integrated stress response (ISR) pathway. We report that reduced expression of miR-183 greatly increases eIF2Bδ protein levels, preventing strong induction of the ISR and eIF2α phosphorylation, by preferential interaction with P-eIF2α. eIF2Bδ overexpression is essential for BC cell invasion, metastasis, maintenance of metastases, and breast CSC expansion in animal models. Increased expression of eIF2Bδ, a site of action of the drug ISRIB that also prevents ISR signaling, is essential for breast CSC maintenance and metastatic capacity.
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Affiliation(s)
- Malavika Gupta
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY10016
| | - Beth A. Walters
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY10016
| | - Olga Katsara
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY10016
| | - Karol Granados Blanco
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY10016
| | - Phillip A. Geter
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY10016
| | - Robert J. Schneider
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY10016
- New York University Perlmutter Cancer Center, New York University Grossman School of Medicine, New York, NY10016
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10
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Aloise C, Schipper JG, de Groot RJ, van Kuppeveld FJM. Move and countermove: the integrated stress response in picorna- and coronavirus-infected cells. Curr Opin Immunol 2022; 79:102254. [PMID: 36274340 PMCID: PMC9515345 DOI: 10.1016/j.coi.2022.102254] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 09/25/2022] [Indexed: 01/29/2023]
Abstract
Viruses, when entering their host cells, are met by a fierce intracellular immune defense. One prominent antiviral pathway is the integrated stress response (ISR). Upon activation of the ISR - typically though not exclusively upon detection of dsRNA - translation-initiation factor eukaryotic initiation factor 2 (eIF2) becomes phosphorylated to act as an inhibitor of guanine nucleotide-exchange factor eIF2B. Thus, with the production of ternary complex blocked, a global translational arrest ensues. Successful virus replication hinges on effective countermeasures. Here, we review ISR antagonists and antagonistic mechanisms employed by picorna- and coronaviruses. Special attention will be given to a recently discovered class of viral antagonists that inhibit the ISR by targeting eIF2B, thereby allowing unabated translation initiation even at exceedingly high levels of phosphorylated eIF2.
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11
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Wuerth JD, Weber F. Shielding the mRNA-translation factor eIF2B from inhibitory p-eIF2 as a viral strategy to evade protein kinase R-mediated innate immunity. Curr Opin Immunol 2022; 78:102251. [PMID: 36242870 DOI: 10.1016/j.coi.2022.102251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 09/05/2022] [Indexed: 01/29/2023]
Abstract
The interferon-regulated kinase PKR (protein kinase RNA-activated) is a potent innate immune factor against a broad range of viruses. Being part of the integrated stress response (ISR), its restrictive effect is predominantly exerted by phosphorylating the eukaryotic translation-initiation factor eIF2, thereby turning it into an inhibitor of translation-initiation factor eIF2B. A plethora of viruses are known to evade the shutdown of cellular mRNA translation by interfering either with PKR activation or with eIF2 phosphorylation. Recently, a novel PKR evasion strategy was described: proteins from three taxonomically distinct RNA viruses allow for full PKR activation and eIF2 phosphorylation in the infected cell, but protect eIF2B from inhibition by phosphorylated eIF2, thus enabling mRNA translation in the presence of an activated ISR.
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Affiliation(s)
- Jennifer D Wuerth
- Institute of Innate Immunity, Medical Faculty, University of Bonn, 53127 Bonn, Germany
| | - Friedemann Weber
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, D-35392 Giessen, Germany.
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12
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Wongkittichote P, Mar SS, McKinstry RC, Nguyen H. Case Report: A Novel EIF2B3 Pathogenic Variant in Central Nervous System Hypomyelination/Vanishing White Matter. Front Genet 2022; 13:893057. [PMID: 35783294 PMCID: PMC9247212 DOI: 10.3389/fgene.2022.893057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/11/2022] [Indexed: 11/23/2022] Open
Abstract
Leukodystrophies are a group of heterogeneous disorders affecting brain myelin. Among those, childhood ataxia with central nervous system hypomyelination/vanishing white matter (CACH/VWM) is one of the more common inherited leukodystrophies. Pathogenic variants in one of the genes encoding five subunits of EIF2B are associated with CACH/VWM. Herein, we presented a case of CACH/VWM who developed ataxia following a minor head injury. Brain magnetic resonance imaging showed extensive white matter signal abnormality. Diagnosis of CACH/VWM was confirmed by the presence of compound heterozygous variants in EIF2B3: the previously known pathogenic variant c c.260C>T (p.Ala87Val) and the novel variant c.673C>T (p.Arg225Trp). Based on the American College of Medical Genetics (ACMG) recommendations, we classified p.Arg225Trp as likely pathogenic. We report a novel variant in a patient with CACH/VWM and highlight the importance of genetic testing in patients with leukodystrophies.
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Affiliation(s)
- Parith Wongkittichote
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University School of Medicine, St Louis, MO, United States
| | - Soe Soe Mar
- Division of Pediatric Neurology, Department of Neurology, Washington University School of Medicine, St Louis, MO, United States
| | - Robert C. McKinstry
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO, United States
| | - Hoanh Nguyen
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University School of Medicine, St Louis, MO, United States
- *Correspondence: Hoanh Nguyen,
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13
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The role of eIF2 phosphorylation in cell and organismal physiology: new roles for well-known actors. Biochem J 2022; 479:1059-1082. [PMID: 35604373 DOI: 10.1042/bcj20220068] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/21/2022] [Accepted: 04/25/2022] [Indexed: 02/06/2023]
Abstract
Control of protein synthesis (mRNA translation) plays key roles in shaping the proteome and in many physiological, including homeostatic, responses. One long-known translational control mechanism involves phosphorylation of initiation factor, eIF2, which is catalysed by any one of four protein kinases, which are generally activated in response to stresses. They form a key arm of the integrated stress response (ISR). Phosphorylated eIF2 inhibits eIF2B (the protein that promotes exchange of eIF2-bound GDP for GTP) and thus impairs general protein synthesis. However, this mechanism actually promotes translation of certain mRNAs by virtue of specific features they possess. Recent work has uncovered many previously unknown features of this regulatory system. Several studies have yielded crucial insights into the structure and control of eIF2, including that eIF2B is regulated by several metabolites. Recent studies also reveal that control of eIF2 and the ISR helps determine organismal lifespan and surprising roles in sensing mitochondrial stresses and in controlling the mammalian target of rapamycin (mTOR). The latter effect involves an unexpected role for one of the eIF2 kinases, HRI. Phosphoproteomic analysis identified new substrates for another eIF2 kinase, Gcn2, which senses the availability of amino acids. Several genetic disorders arise from mutations in genes for eIF2α kinases or eIF2B (i.e. vanishing white matter disease, VWM and microcephaly, epileptic seizures, microcephaly, hypogenitalism, diabetes and obesity, MEHMO). Furthermore, the eIF2-mediated ISR plays roles in cognitive decline associated with Alzheimer's disease. New findings suggest potential therapeutic value in interfering with the ISR in certain settings, including VWM, for example by using compounds that promote eIF2B activity.
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14
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Regulation and function of elF2B in neurological and metabolic disorders. Biosci Rep 2022; 42:231311. [PMID: 35579296 PMCID: PMC9208314 DOI: 10.1042/bsr20211699] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 04/28/2022] [Accepted: 05/12/2022] [Indexed: 11/27/2022] Open
Abstract
Eukaryotic initiation factor 2B, eIF2B is a guanine nucleotide exchange, factor with a central role in coordinating the initiation of translation. During stress and disease, the activity of eIF2B is inhibited via the phosphorylation of its substrate eIF2 (p-eIF2α). A number of different kinases respond to various stresses leading to the phosphorylation of the alpha subunit of eIF2, and collectively this regulation is known as the integrated stress response, ISR. This targeting of eIF2B allows the cell to regulate protein synthesis and reprogramme gene expression to restore homeostasis. Advances within structural biology have furthered our understanding of how eIF2B interacts with eIF2 in both the productive GEF active form and the non-productive eIF2α phosphorylated form. Here, current knowledge of the role of eIF2B in the ISR is discussed within the context of normal and disease states focusing particularly on diseases such as vanishing white matter disease (VWMD) and permanent neonatal diabetes mellitus (PNDM), which are directly linked to mutations in eIF2B. The role of eIF2B in synaptic plasticity and memory formation is also discussed. In addition, the cellular localisation of eIF2B is reviewed and considered along with the role of additional in vivo eIF2B binding factors and protein modifications that may play a role in modulating eIF2B activity during health and disease.
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15
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Stepwise assembly of the eukaryotic translation initiation factor 2 (eIF2) complex. J Biol Chem 2022; 298:101583. [PMID: 35031321 PMCID: PMC8844851 DOI: 10.1016/j.jbc.2022.101583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 01/02/2022] [Accepted: 01/04/2022] [Indexed: 11/22/2022] Open
Abstract
The eukaryotic translation initiation factor 2 (eIF2) has key functions in the initiation step of protein synthesis. eIF2 guides the initiator tRNA to the ribosome, participates in scanning of the mRNA molecule, supports selection of the start codon, and modulates the translation of mRNAs in response to stress. eIF2 comprises a heterotrimeric complex whose assembly depends on the ATP-grasp protein Cdc123. Mutations of the eIF2γ subunit that compromise eIF2 complex formation cause severe neurological disease in humans. To this date, however, details about the assembly mechanism, step order, and the individual functions of eIF2 subunits remain unclear. Here, we quantified assembly intermediates and studied the behavior of various binding site mutants in budding yeast. Based on these data, we present a model in which a Cdc123-mediated conformational change in eIF2γ exposes binding sites for eIF2α and -β subunits. Contrary to an earlier hypothesis, we found that the associations of eIF2α and -β with the γ-subunit are independent of each other, but the resulting heterodimers are non-functional and fail to bind the guanosine exchange factor eIF2B. In addition, levels of eIF2α influence the rate of eIF2 assembly. By binding to eIF2γ, eIF2α displaces Cdc123 and thereby completes the assembly process. Experiments in human cell culture indicate that the mechanism of eIF2 assembly is conserved between yeast and humans. This study sheds light on an essential step in eukaryotic translation initiation, the dysfunction of which is linked to human disease.
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16
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Sekine Y, Ron D, Zyryanova AF. Fluorescence Intensity-Based eIF2B's Guanine Nucleotide-Exchange Factor Activity Assay. Methods Mol Biol 2022; 2428:187-196. [PMID: 35171481 DOI: 10.1007/978-1-0716-1975-9_12] [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] [Indexed: 06/14/2023]
Abstract
Guanine nucleotide-exchange factors (GEFs) activate the function of guanine nucleotide-binding proteins (G-proteins) by promoting the exchange of GDP for GTP on the latter. Here, we describe a protocol for in vitro measurements of the GEF activity of eukaryotic translation initiation factor 2B, eIF2B, toward its substrate eIF2. This protocol provides a relatively simple method for determining the eIF2B's GEF activity in crude cell extracts. The eIF2 heterotrimeric substrate, with phosphorylated or unphosphorylated eIF2α, is prepared by immunoprecipitation, following subsequent loading of a fluorescent BODIPY-FL dye-attached GDP. The exchange of the bound fluorescent GDP molecule for an unlabeled one on eIF2 promoted by eIF2B is monitored kinetically using a fluorescence microplate reader.
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Affiliation(s)
- Yusuke Sekine
- Division of Endocrinology and Metabolism, Department of Medicine, Aging Institute, University of Pittsburgh, Pittsburgh, PA, USA.
| | - David Ron
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK
| | - Alisa F Zyryanova
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK
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17
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Krzyzosiak A, Pitera AP, Bertolotti A. An Overview of Methods for Detecting eIF2α Phosphorylation and the Integrated Stress Response. Methods Mol Biol 2022; 2428:3-18. [PMID: 35171470 DOI: 10.1007/978-1-0716-1975-9_1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Phosphorylation of the translation initiation factor eIF2α is an adaptive signaling event that is essential for cell and organismal survival from yeast to humans. It is central to the integrated stress response (ISR) that maintains cellular homeostasis in the face of threats ranging from viral infection, amino acid, oxygen, and heme deprivation to the accumulation of misfolded proteins in the endoplasmic reticulum. Phosphorylation of eIF2α has broad physiological, pathological, and therapeutic relevance. However, despite more than two decades of research and growing pharmacological interest, phosphorylation of eIF2α remains difficult to detect and quantify, because of its transient nature and because substoichiometric amounts of this modification are sufficient to profoundly reshape cellular physiology. This review aims to provide a roadmap for facilitating a robust evaluation of eIF2α phosphorylation and its downstream consequences in cells and organisms.
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18
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Circir A, Koksal Bicakci G, Savas B, Doken DN, Henden ŞO, Can T, Karaca E, Erson-Bensan AE. A C-term truncated EIF2Bγ protein encoded by an intronically polyadenylated isoform introduces unfavorable EIF2Bγ-EIF2γ interactions. Proteins 2021; 90:889-897. [PMID: 34796993 DOI: 10.1002/prot.26284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 11/01/2021] [Accepted: 11/15/2021] [Indexed: 11/11/2022]
Abstract
Eukaryotic translation initiates upon recruitment of the EIF2-GTP·Met-tRNAi ternary complex (TC) to the ribosomes. EIF2 (α, β, γ subunits) is a GTPase. The GDP to GTP exchange within EIF2 is facilitated by the guanine nucleotide exchange factor EIF2B (α-ε subunits). During stress-induced conditions, phosphorylation of the α-subunit of EIF2 turns EIF2 into an inhibitor of EIF2B. In turn, inhibition of EIF2B decreases TC formation and triggers the internal stress response (ISR), which determines the cell fate. Deregulated ISR has been linked to neurodegenerative disorders and cancer, positioning EIF2B as a promising therapeutic target. Hence, a better understanding of the mechanisms/factors that regulate EIF2B activity is required. Here, combining transcript and protein level analyses, we describe an intronically polyadenylated (IPA) transcript of EIF2B's γ-subunit. We show that the IPA mRNA isoform is translated into a C-terminus truncated protein. Using structural modeling, we predict that the truncated EIF2Bγ protein has unfavorable interactions with EIF2γ, leading to a potential decrease in the stability of the nonproductive EIF2:EIF2B complex. While we discovered and confirmed the IPA mRNA isoform in breast cancer cells, the expression of this isoform is not cancer-specific and is widely present in normal tissues. Overall, our data show that a truncated EIF2Bγ protein co-exists with the canonical protein and is an additional player to regulate the equilibrium between productive and nonproductive states of the EIF2:EIF2B complex. These results may have implications in stress-induced translation control in normal and disease states. Our combinatorial approach demonstrates the need to study noncanonical mRNA and protein isoforms to understand protein interactions and intricate molecular mechanisms.
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Affiliation(s)
- Ayca Circir
- Department of Biological Sciences, Middle East Technical University (METU), Ankara, Turkey
| | - Gozde Koksal Bicakci
- Department of Biological Sciences, Middle East Technical University (METU), Ankara, Turkey
| | - Busra Savas
- Izmir Biomedicine and Genome Center, Balcova, Izmir, Turkey.,Izmir International Biomedicine and Genome Institute, Dokuz Eylul University, Balcova, Izmir, Turkey
| | - Didem Naz Doken
- Department of Biological Sciences, Middle East Technical University (METU), Ankara, Turkey
| | - Şevki Onur Henden
- Department of Computer Engineering, Middle East Technical University (METU), Ankara, Turkey
| | - Tolga Can
- Department of Computer Engineering, Middle East Technical University (METU), Ankara, Turkey.,Cancer System Biology Laboratory (CanSyL), Graduate School of Informatics, Middle East Technical University (METU), Ankara, Turkey
| | - Ezgi Karaca
- Izmir Biomedicine and Genome Center, Balcova, Izmir, Turkey.,Izmir International Biomedicine and Genome Institute, Dokuz Eylul University, Balcova, Izmir, Turkey
| | - Ayse Elif Erson-Bensan
- Department of Biological Sciences, Middle East Technical University (METU), Ankara, Turkey.,Cancer System Biology Laboratory (CanSyL), Graduate School of Informatics, Middle East Technical University (METU), Ankara, Turkey
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19
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Schramm F, Borst A, Linne U, Soppa J. Elucidation of the Translation Initiation Factor Interaction Network of Haloferax volcanii Reveals Coupling of Transcription and Translation in Haloarchaea. Front Microbiol 2021; 12:742806. [PMID: 34764944 PMCID: PMC8576121 DOI: 10.3389/fmicb.2021.742806] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 09/29/2021] [Indexed: 02/04/2023] Open
Abstract
Translation is an important step in gene expression. Initiation of translation is rate-limiting, and it is phylogenetically more diverse than elongation or termination. Bacteria contain only three initiation factors. In stark contrast, eukaryotes contain more than 10 (subunits of) initiation factors (eIFs). The genomes of archaea contain many genes that are annotated to encode archaeal homologs of eukaryotic initiation factors (aIFs). However, experimental characterization of aIFs is scarce and mostly restricted to very few species. To broaden the view, the protein-protein interaction network of aIFs in the halophilic archaeon Haloferax volcanii has been characterized. To this end, tagged versions of 14 aIFs were overproduced, affinity isolated, and the co-isolated binding partners were identified by peptide mass fingerprinting and MS/MS analyses. The aIF-aIF interaction network was resolved, and it was found to contain two interaction hubs, (1) the universally conserved factor aIF5B, and (2) a protein that has been annotated as the enzyme ribose-1,5-bisphosphate isomerase, which we propose to rename to aIF2Bα. Affinity isolation of aIFs also led to the co-isolation of many ribosomal proteins, but also transcription factors and subunits of the RNA polymerase (Rpo). To analyze a possible coupling of transcription and translation, seven tagged Rpo subunits were overproduced, affinity isolated, and co-isolated proteins were identified. The Rpo interaction network contained many transcription factors, but also many ribosomal proteins as well as the initiation factors aIF5B and aIF2Bα. These results showed that transcription and translation are coupled in haloarchaea, like in Escherichia coli. It seems that aIF5B and aIF2Bα are not only interaction hubs in the translation initiation network, but also key players in the transcription-translation coupling.
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Affiliation(s)
- Franziska Schramm
- Institute for Molecular Biosciences, Biocentre, Goethe-University, Frankfurt, Germany
| | - Andreas Borst
- Institute for Molecular Biosciences, Biocentre, Goethe-University, Frankfurt, Germany
| | - Uwe Linne
- Mass Spectrometry Facility, Department of Chemistry, Phillipps University Marburg, Marburg, Germany
| | - Jörg Soppa
- Institute for Molecular Biosciences, Biocentre, Goethe-University, Frankfurt, Germany
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20
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Alford BD, Tassoni-Tsuchida E, Khan D, Work JJ, Valiant G, Brandman O. ReporterSeq reveals genome-wide dynamic modulators of the heat shock response across diverse stressors. eLife 2021; 10:57376. [PMID: 34223816 PMCID: PMC8257254 DOI: 10.7554/elife.57376] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 06/11/2021] [Indexed: 12/16/2022] Open
Abstract
Understanding cellular stress response pathways is challenging because of the complexity of regulatory mechanisms and response dynamics, which can vary with both time and the type of stress. We developed a reverse genetic method called ReporterSeq to comprehensively identify genes regulating a stress-induced transcription factor under multiple conditions in a time-resolved manner. ReporterSeq links RNA-encoded barcode levels to pathway-specific output under genetic perturbations, allowing pooled pathway activity measurements via DNA sequencing alone and without cell enrichment or single-cell isolation. We used ReporterSeq to identify regulators of the heat shock response (HSR), a conserved, poorly understood transcriptional program that protects cells from proteotoxicity and is misregulated in disease. Genome-wide HSR regulation in budding yeast was assessed across 15 stress conditions, uncovering novel stress-specific, time-specific, and constitutive regulators. ReporterSeq can assess the genetic regulators of any transcriptional pathway with the scale of pooled genetic screens and the precision of pathway-specific readouts.
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Affiliation(s)
- Brian D Alford
- Department of Biochemistry, Stanford University, Stanford, United States
| | - Eduardo Tassoni-Tsuchida
- Department of Biochemistry, Stanford University, Stanford, United States.,Department of Biology, Stanford University, Stanford, United States
| | - Danish Khan
- Department of Biochemistry, Stanford University, Stanford, United States
| | - Jeremy J Work
- Department of Biochemistry, Stanford University, Stanford, United States
| | - Gregory Valiant
- Department of Computer Science, Stanford University, Stanford, United States
| | - Onn Brandman
- Department of Biochemistry, Stanford University, Stanford, United States
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21
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Papadopoli D, Pollak M, Topisirovic I. The role of GSK3 in metabolic pathway perturbations in cancer. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119059. [PMID: 33989699 DOI: 10.1016/j.bbamcr.2021.119059] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 04/16/2021] [Accepted: 04/17/2021] [Indexed: 01/11/2023]
Abstract
Malignant transformation and tumor progression are accompanied by significant perturbations in metabolic programs. As such, cancer cells support high ATP turnover to construct the building blocks needed to fuel neoplastic growth. The coordination of metabolic networks in malignant cells is dependent on the collaboration with cellular signaling pathways. Glycogen synthase kinase 3 (GSK3) lies at the convergence of several signaling axes, including the PI3K/AKT/mTOR, AMPK, and Wnt pathways, which influence cancer initiation, progression and therapeutic responses. Accordingly, GSK3 modulates metabolic processes, including protein and lipid synthesis, glucose and mitochondrial metabolism, as well as autophagy. In this review, we highlight current knowledge of the role of GSK3 in metabolic perturbations in cancer.
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Affiliation(s)
- David Papadopoli
- Lady Davis Institute for Medical Research, 3755 Chemin de la Côte-Sainte-Catherine, Montréal, QC H3T 1E2, Canada; Gerald Bronfman Department of Oncology, McGill University, 5100 Maisonneuve Blvd West, Montréal, QC H4A 3T2, Canada.
| | - Michael Pollak
- Lady Davis Institute for Medical Research, 3755 Chemin de la Côte-Sainte-Catherine, Montréal, QC H3T 1E2, Canada; Gerald Bronfman Department of Oncology, McGill University, 5100 Maisonneuve Blvd West, Montréal, QC H4A 3T2, Canada; Department of Medicine, Division of Experimental Medicine, McGill University, 1001 Décarie Blvd, Montréal, QC H4A 3J1, Canada
| | - Ivan Topisirovic
- Lady Davis Institute for Medical Research, 3755 Chemin de la Côte-Sainte-Catherine, Montréal, QC H3T 1E2, Canada; Gerald Bronfman Department of Oncology, McGill University, 5100 Maisonneuve Blvd West, Montréal, QC H4A 3T2, Canada; Department of Medicine, Division of Experimental Medicine, McGill University, 1001 Décarie Blvd, Montréal, QC H4A 3J1, Canada; Department of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montréal, QC H3G 1Y6, Canada
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22
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Read RW, Schlauch KA, Lombardi VC, Cirulli ET, Washington NL, Lu JT, Grzymski JJ. Genome-Wide Identification of Rare and Common Variants Driving Triglyceride Levels in a Nevada Population. Front Genet 2021; 12:639418. [PMID: 33763119 PMCID: PMC7982958 DOI: 10.3389/fgene.2021.639418] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 02/12/2021] [Indexed: 01/08/2023] Open
Abstract
Clinical conditions correlated with elevated triglyceride levels are well-known: coronary heart disease, hypertension, and diabetes. Underlying genetic and phenotypic mechanisms are not fully understood, partially due to lack of coordinated genotypic-phenotypic data. Here we use a subset of the Healthy Nevada Project, a population of 9,183 sequenced participants with longitudinal electronic health records to examine consequences of altered triglyceride levels. Specifically, Healthy Nevada Project participants sequenced by the Helix Exome+ platform were cross-referenced to their electronic medical records to identify: (1) rare and common single-variant genome-wide associations; (2) gene-based associations using a Sequence Kernel Association Test; (3) phenome-wide associations with triglyceride levels; and (4) pleiotropic variants linked to triglyceride levels. The study identified 549 significant single-variant associations (p < 8.75 × 10-9), many in chromosome 11's triglyceride hotspot: ZPR1, BUD13, APOC3, APOA5. A well-known protective loss-of-function variant in APOC3 (R19X) was associated with a 51% decrease in triglyceride levels in the cohort. Sixteen gene-based triglyceride associations were identified; six of these genes surprisingly did not include a single variant with significant associations. Results at the variant and gene level were validated with the UK Biobank. The combination of a single-variant genome-wide association, a gene-based association method, and phenome wide-association studies identified rare and common variants, genes, and phenotypes associated with elevated triglyceride levels, some of which may have been overlooked with standard approaches.
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Affiliation(s)
- Robert W. Read
- Center for Genomic Medicine, Desert Research Institute, Reno, NV, United States
| | - Karen A. Schlauch
- Center for Genomic Medicine, Desert Research Institute, Reno, NV, United States
| | - Vincent C. Lombardi
- Department of Microbiology and Immunology, School of Medicine, University of Nevada, Reno, Reno, NV, United States
| | | | | | - James T. Lu
- Helix Opco, LLC., San Mateo, CA, United States
| | - Joseph J. Grzymski
- Center for Genomic Medicine, Desert Research Institute, Reno, NV, United States
- Renown Health, Reno, NV, United States
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23
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Houston R, Sekine S, Sekine Y. The coupling of translational control and stress responses. J Biochem 2021; 168:93-102. [PMID: 32484875 DOI: 10.1093/jb/mvaa061] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 05/25/2020] [Indexed: 12/16/2022] Open
Abstract
The translation of messenger RNA (mRNA) into protein is a multistep process by which genetic information transcribed into an mRNA is decoded to produce a specific polypeptide chain of amino acids. Ribosomes play a central role in translation by coordinately working with various translation regulatory factors and aminoacyl-transfer RNAs. Various stresses attenuate the ribosomal synthesis in the nucleolus as well as the translation rate in the cytosol. To efficiently reallocate cellular energy and resources, mammalian cells are endowed with mechanisms that directly link the suppression of translation-related processes to the activation of stress adaptation programmes. This review focuses on the integrated stress response (ISR) and the nucleolar stress response (NSR) both of which are activated by various stressors and selectively upregulate stress-responsive transcription factors. Emerging findings have delineated the detailed molecular mechanisms of the ISR and NSR and expanded their physiological and pathological significances.
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Affiliation(s)
- Ryan Houston
- Aging Institute, Department of Medicine, University of Pittsburgh, 100 Technology Drive, Pittsburgh, PA, 15219 USA
| | - Shiori Sekine
- Aging Institute, Department of Medicine, University of Pittsburgh, 100 Technology Drive, Pittsburgh, PA, 15219 USA.,Division of Cardiology, Department of Medicine, University of Pittsburgh, 3550 Terrace Street, Pittsburgh, PA 15261, USA
| | - Yusuke Sekine
- Aging Institute, Department of Medicine, University of Pittsburgh, 100 Technology Drive, Pittsburgh, PA, 15219 USA.,Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, 3550 Terrace Street, Pittsburgh, PA 15261, USA
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