1
|
Fernandez SG, Ferguson L, Ingolia NT. Ribosome rescue factor PELOTA modulates translation start site choice for C/EBPα protein isoforms. Life Sci Alliance 2024; 7:e202302501. [PMID: 38803235 PMCID: PMC11109482 DOI: 10.26508/lsa.202302501] [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: 11/28/2023] [Revised: 04/15/2024] [Accepted: 04/16/2024] [Indexed: 05/29/2024] Open
Abstract
Translation initiation at alternative start sites can dynamically control the synthesis of two or more functionally distinct protein isoforms from a single mRNA. Alternate isoforms of the developmental transcription factor CCAAT/enhancer-binding protein α (C/EBPα) produced from different start sites exert opposing effects during myeloid cell development. This choice between alternative start sites depends on sequence features of the CEBPA transcript, including a regulatory uORF, but the molecular basis is not fully understood. Here, we identify the factors that affect C/EBPα isoform choice using a sensitive and quantitative two-color fluorescent reporter coupled with CRISPRi screening. Our screen uncovered a role of the ribosome rescue factor PELOTA (PELO) in promoting the expression of the longer C/EBPα isoform by directly removing inhibitory unrecycled ribosomes and through indirect effects mediated by the mechanistic target of rapamycin kinase. Our work uncovers further links between ribosome recycling and translation reinitiation that regulate a key transcription factor, with implications for normal hematopoiesis and leukemogenesis.
Collapse
Affiliation(s)
- Samantha G Fernandez
- https://ror.org/01an7q238 Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Lucas Ferguson
- https://ror.org/01an7q238 Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- https://ror.org/01an7q238 Center for Computational Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
| | - Nicholas T Ingolia
- https://ror.org/01an7q238 Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- https://ror.org/01an7q238 Center for Computational Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
| |
Collapse
|
2
|
McLean S, Lee M, Liu W, Hameed R, Gujjala VA, Zhou X, Kaeberlein M, Kaya A. Molecular Mechanisms of Genotype-Dependent Lifespan Variation Mediated by Caloric Restriction: Insight from Wild Yeast Isolates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.17.585422. [PMID: 38559208 PMCID: PMC10979966 DOI: 10.1101/2024.03.17.585422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Caloric restriction (CR) is known to extend lifespan across different species and holds great promise for preventing human age-onset pathologies. However, two major challenges exist. First, despite extensive research, the mechanisms of lifespan extension in response to CR remain elusive. Second, genetic differences causing variations in response to CR and genetic factors contributing to variability of CR response on lifespan are largely unknown. Here, we took advantage of natural genetic variation across 46 diploid wild yeast isolates of Saccharomyces species and the lifespan variation under CR conditions to uncover the molecular factors associated with CR response types. We identified genes and metabolic pathways differentially regulated in CR-responsive versus non-responsive strains. Our analysis revealed that altered mitochondrial function and activation of GCN4-mediated environmental stress response are inevitably linked to lifespan variation in response to CR and a unique mitochondrial metabolite might be utilized as a predictive marker for CR response rate. In sum, our data suggests that the effects of CR on longevity may not be universal, even among the closely related species or strains of a single species. Since mitochondrial-mediated signaling pathways are evolutionarily conserved, the dissection of related genetic pathways will be relevant to understanding the mechanism by which CR elicits its longevity effect.
Collapse
Affiliation(s)
- Samantha McLean
- Department of Biology, Virginia Commonwealth University, Richmond, VA 23284 USA
| | - Mitchell Lee
- Department of Pathology, University of Washington, Seattle, WA, 98195, USA
- Ora Biomedical, Seattle, WA, 98168, USA
| | - Weiqiang Liu
- Key Laboratory of Animal Ecology and Conservation Biology, Chinese Academy of Sciences, Institute of Zoology, Beijing, China
| | - Rohil Hameed
- Department of Biology, Virginia Commonwealth University, Richmond, VA 23284 USA
| | - Vikas Anil Gujjala
- Department of Biology, Virginia Commonwealth University, Richmond, VA 23284 USA
| | - Xuming Zhou
- Key Laboratory of Animal Ecology and Conservation Biology, Chinese Academy of Sciences, Institute of Zoology, Beijing, China
| | - Matt Kaeberlein
- Department of Pathology, University of Washington, Seattle, WA, 98195, USA
- Optispan, Seattle, WA, 98168, USA
| | - Alaattin Kaya
- Department of Biology, Virginia Commonwealth University, Richmond, VA 23284 USA
| |
Collapse
|
3
|
Ryoo HD. The integrated stress response in metabolic adaptation. J Biol Chem 2024; 300:107151. [PMID: 38462161 PMCID: PMC10998230 DOI: 10.1016/j.jbc.2024.107151] [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: 11/15/2023] [Revised: 02/28/2024] [Accepted: 03/03/2024] [Indexed: 03/12/2024] Open
Abstract
The integrated stress response (ISR) refers to signaling pathways initiated by stress-activated eIF2α kinases. Distinct eIF2α kinases respond to different stress signals, including amino acid deprivation and mitochondrial stress. Such stress-induced eIF2α phosphorylation attenuates general mRNA translation and, at the same time, stimulates the preferential translation of specific downstream factors to orchestrate an adaptive gene expression program. In recent years, there have been significant new advances in our understanding of ISR during metabolic stress adaptation. Here, I discuss those advances, reviewing among others the ISR activation mechanisms in response to amino acid deprivation and mitochondrial stress. In addition, I review how ISR regulates the amino acid metabolic pathways and how changes in the ISR impact the physiology and pathology of various disease models.
Collapse
Affiliation(s)
- Hyung Don Ryoo
- Department of Cell Biology, New York University Grossman School of Medicine, New York, New York, USA.
| |
Collapse
|
4
|
Xu J, Hörner M, Nagel M, Korneck M, Noß M, Hauser S, Schöls L, Admard J, Casadei N, Schüle R. Unraveling Axonal Transcriptional Landscapes: Insights from iPSC-Derived Cortical Neurons and Implications for Motor Neuron Degeneration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.26.586780. [PMID: 38585749 PMCID: PMC10996649 DOI: 10.1101/2024.03.26.586780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Neuronal function and pathology are deeply influenced by the distinct molecular profiles of the axon and soma. Traditional studies have often overlooked these differences due to the technical challenges of compartment specific analysis. In this study, we employ a robust RNA-sequencing (RNA-seq) approach, using microfluidic devices, to generate high-quality axonal transcriptomes from iPSC-derived cortical neurons (CNs). We achieve high specificity of axonal fractions, ensuring sample purity without contamination. Comparative analysis revealed a unique and specific transcriptional landscape in axonal compartments, characterized by diverse transcript types, including protein-coding mRNAs, ribosomal proteins (RPs), mitochondrial-encoded RNAs, and long non-coding RNAs (lncRNAs). Previous works have reported the existence of transcription factors (TFs) in the axon. Here, we detect a subset of previously unreported TFs specific to the axon and indicative of their active participation in transcriptional regulation. To investigate transcripts and pathways essential for central motor neuron (MN) degeneration and maintenance we analyzed KIF1C-knockout (KO) CNs, modeling hereditary spastic paraplegia (HSP), a disorder associated with prominent length-dependent degeneration of central MN axons. We found that several key factors crucial for survival and health were absent in KIF1C-KO axons, highlighting a possible role of these also in other neurodegenerative diseases. Taken together, this study underscores the utility of microfluidic devices in studying compartment-specific transcriptomics in human neuronal models and reveals complex molecular dynamics of axonal biology. The impact of KIF1C on the axonal transcriptome not only deepens our understanding of MN diseases but also presents a promising avenue for exploration of compartment specific disease mechanisms.
Collapse
|
5
|
Avelar RA, Gupta R, Carvette G, da Veiga Leprevost F, Colina J, Teitel J, Nesvizhskii AI, O’Connor CM, Hatzoglou M, Shenolikar S, Arvan P, Narla G, DiFeo A. Integrated stress response plasticity governs normal cell adaptation to chronic stress via the PP2A-TFE3-ATF4 pathway. RESEARCH SQUARE 2024:rs.3.rs-4013396. [PMID: 38585734 PMCID: PMC10996823 DOI: 10.21203/rs.3.rs-4013396/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
The integrated stress response (ISR) regulates cell fate during conditions of stress by leveraging the cell's capacity to endure sustainable and efficient adaptive stress responses. Protein phosphatase 2A (PP2A) activity modulation has been shown to be successful in achieving both therapeutic efficacy and safety across various cancer models; however, the molecular mechanisms driving its selective antitumor effects remain unclear. Here, we show for the first time that ISR plasticity relies on PP2A activation to regulate drug response and dictate cellular fate under conditions of chronic stress. We demonstrate that genetic and chemical modulation of the PP2A leads to chronic proteolytic stress and triggers an ISR to dictate cell fate. More specifically, we uncovered that the PP2A-TFE3-ATF4 pathway governs ISR cell plasticity during endoplasmic reticular and cellular stress independent of the unfolded protein response. We further show that normal cells reprogram their genetic signatures to undergo ISR-mediated adaptation and homeostatic recovery thereby successfully avoiding toxicity following PP2A-mediated stress. Conversely, oncogenic specific cytotoxicity induced by chemical modulation of PP2A is achieved by activating chronic and irreversible ISR in cancer cells. Our findings propose that a differential response to chemical modulation of PP2A is determined by intrinsic ISR plasticity, providing a novel biological vulnerability to selectively induce cancer cell death and improve targeted therapeutic efficacy.
Collapse
Affiliation(s)
- Rita A. Avelar
- Department of Pathology, The University of Michigan, Ann Arbor, MI 48109, USA
- Rogel Cancer Center, The University of Michigan, Ann Arbor, MI 48109, USA
| | - Riya Gupta
- Department of Pathology, The University of Michigan, Ann Arbor, MI 48109, USA
- Rogel Cancer Center, The University of Michigan, Ann Arbor, MI 48109, USA
| | - Gracie Carvette
- Department of Pathology, The University of Michigan, Ann Arbor, MI 48109, USA
- Rogel Cancer Center, The University of Michigan, Ann Arbor, MI 48109, USA
| | | | - Jose Colina
- Department of Pathology, The University of Michigan, Ann Arbor, MI 48109, USA
- Rogel Cancer Center, The University of Michigan, Ann Arbor, MI 48109, USA
| | - Jessica Teitel
- Department of Pathology, The University of Michigan, Ann Arbor, MI 48109, USA
- Rogel Cancer Center, The University of Michigan, Ann Arbor, MI 48109, USA
| | - Alexey I. Nesvizhskii
- Department of Pathology, The University of Michigan, Ann Arbor, MI 48109, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Caitlin M. O’Connor
- Rogel Cancer Center, The University of Michigan, Ann Arbor, MI 48109, USA
- Department of Internal Medicine, Division of Genetic Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Maria Hatzoglou
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Shirish Shenolikar
- Emeritus Professor, Duke-NUS Medical School, Singapore
- Professor Emeritus, Duke University School of Medicine, USA
| | - Peter Arvan
- Division of Metabolism Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI 48109, USA
| | - Goutham Narla
- Rogel Cancer Center, The University of Michigan, Ann Arbor, MI 48109, USA
- Department of Internal Medicine, Division of Genetic Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Analisa DiFeo
- Department of Pathology, The University of Michigan, Ann Arbor, MI 48109, USA
- Rogel Cancer Center, The University of Michigan, Ann Arbor, MI 48109, USA
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI 48109, USA
| |
Collapse
|
6
|
Jendruchová K, Gaikwad S, Poncová K, Gunišová S, Valášek LS, Hinnebusch AG. Impacts of yeast Tma20/MCTS1, Tma22/DENR and Tma64/eIF2D on translation reinitiation and ribosome recycling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.06.583729. [PMID: 38903097 PMCID: PMC11188067 DOI: 10.1101/2024.03.06.583729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
Recycling of 40S ribosomal subunits following translation termination, entailing release of deacylated tRNA and dissociation of the empty 40S subunit from mRNA, involves yeast Tma20/Tma22 heterodimer and Tma64, counterparts of mammalian MCTS1/DENR and eIF2D. MCTS1/DENR enhance reinitiation at short upstream open reading frames (uORFs) harboring penultimate codons that confer dependence on these factors in bulk 40S recycling. Tma factors, by contrast, inhibited reinitiation at particular uORFs in extracts; however, their roles at regulatory uORFs in vivo were unknown. We examined effects of eliminating Tma proteins on reinitiation at regulatory uORFs mediating translational control of GCN4 optimized for either promoting (uORF1) or preventing (uORF4) reinitiation. We found that the Tma proteins generally impede reinitiation at native uORF4 and uORF4 variants equipped with various penultimate codons regardless of their Tma-dependence in bulk recycling. The Tma factors have no effect on reinitiation at native uORF1, and equipping uORF1 with Tma-dependent penultimate codons generally did not confer Tma-dependent reinitiation; nor did converting the uORFs to AUG-stop elements. Thus, effects of the Tma proteins vary depending on the reinitiation potential of the uORF and the penultimate codon, but unlike in mammals, are not principally dictated by the Tma-dependence of the codon in bulk 40S recycling.
Collapse
|
7
|
Bhatter N, Dmitriev SE, Ivanov P. Cell death or survival: Insights into the role of mRNA translational control. Semin Cell Dev Biol 2024; 154:138-154. [PMID: 37357122 PMCID: PMC10695129 DOI: 10.1016/j.semcdb.2023.06.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 06/15/2023] [Accepted: 06/15/2023] [Indexed: 06/27/2023]
Abstract
Cellular stress is an intrinsic part of cell physiology that underlines cell survival or death. The ability of mammalian cells to regulate global protein synthesis (aka translational control) represents a critical, yet underappreciated, layer of regulation during the stress response. Various cellular stress response pathways monitor conditions of cell growth and subsequently reshape the cellular translatome to optimize translational outputs. On the molecular level, such translational reprogramming involves an intricate network of interactions between translation machinery, RNA-binding proteins, mRNAs, and non-protein coding RNAs. In this review, we will discuss molecular mechanisms, signaling pathways, and targets of translational control that contribute to cellular adaptation to stress and to cell survival or death.
Collapse
Affiliation(s)
- Nupur Bhatter
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Boston, MA, USA; Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Sergey E Dmitriev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia; Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia
| | - Pavel Ivanov
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Boston, MA, USA; Department of Medicine, Harvard Medical School, Boston, MA, USA; Harvard Initiative for RNA Medicine, Boston, Massachusetts, USA.
| |
Collapse
|
8
|
Williams TD, Rousseau A. Translation regulation in response to stress. FEBS J 2024. [PMID: 38308808 DOI: 10.1111/febs.17076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/07/2023] [Accepted: 01/22/2024] [Indexed: 02/05/2024]
Abstract
Cell stresses occur in a wide variety of settings: in disease, during industrial processes, and as part of normal day-to-day rhythms. Adaptation to these stresses requires cells to alter their proteome. Cells modify the proteins they synthesize to aid proteome adaptation. Changes in both mRNA transcription and translation contribute to altered protein synthesis. Here, we discuss the changes in translational mechanisms that occur following the onset of stress, and the impact these have on stress adaptation.
Collapse
Affiliation(s)
- Thomas D Williams
- MRC-PPU, School of Life Sciences, University of Dundee, UK
- Sir William Dunn School of Pathology, University of Oxford, UK
| | | |
Collapse
|
9
|
Tidu A, Martin F. The interplay between cis- and trans-acting factors drives selective mRNA translation initiation in eukaryotes. Biochimie 2024; 217:20-30. [PMID: 37741547 DOI: 10.1016/j.biochi.2023.09.017] [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: 05/04/2023] [Revised: 07/20/2023] [Accepted: 09/14/2023] [Indexed: 09/25/2023]
Abstract
Translation initiation consists in the assembly of the small and large ribosomal subunits on the start codon. This important step directly modulates the general proteome in living cells. Recently, genome wide studies revealed unexpected translation initiation events from unsuspected novel open reading frames resulting in the synthesis of a so-called 'dark proteome'. Indeed, the identification of the start codon by the translation machinery is a critical step that defines the translational landscape of the cell. Therefore, translation initiation is a highly regulated process in all organisms. In this review, we focus on the various cis- and trans-acting factors that rule the regulation of translation initiation in eukaryotes. Recent discoveries have shown that the guidance of the translation machinery for the choice of the start codon require sophisticated molecular mechanisms. In particular, the 5'UTR and the coding sequences contain cis-acting elements that trigger the use of AUG codons but also non-AUG codons to initiate protein synthesis. The use of these alternative start codons is also largely influenced by numerous trans-acting elements that drive selective mRNA translation in response to environmental changes.
Collapse
Affiliation(s)
- Antonin Tidu
- Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire, Architecture et Réactivité de l'ARN, CNRS UPR9002, 2, allée Konrad Roentgen, F-67084 Strasbourg, France
| | - Franck Martin
- Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire, Architecture et Réactivité de l'ARN, CNRS UPR9002, 2, allée Konrad Roentgen, F-67084 Strasbourg, France.
| |
Collapse
|
10
|
Boone M, Zappa F. Signaling plasticity in the integrated stress response. Front Cell Dev Biol 2023; 11:1271141. [PMID: 38143923 PMCID: PMC10740175 DOI: 10.3389/fcell.2023.1271141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 11/29/2023] [Indexed: 12/26/2023] Open
Abstract
The Integrated Stress Response (ISR) is an essential homeostatic signaling network that controls the cell's biosynthetic capacity. Four ISR sensor kinases detect multiple stressors and relay this information to downstream effectors by phosphorylating a common node: the alpha subunit of the eukaryotic initiation factor eIF2. As a result, general protein synthesis is repressed while select transcripts are preferentially translated, thus remodeling the proteome and transcriptome. Mounting evidence supports a view of the ISR as a dynamic signaling network with multiple modulators and feedback regulatory features that vary across cell and tissue types. Here, we discuss updated views on ISR sensor kinase mechanisms, how the subcellular localization of ISR components impacts signaling, and highlight ISR signaling differences across cells and tissues. Finally, we consider crosstalk between the ISR and other signaling pathways as a determinant of cell health.
Collapse
|
11
|
Jackson KG, Way GW, Zeng J, Lipp MK, Zhou H. The Dynamic Role of Endoplasmic Reticulum Stress in Chronic Liver Disease. THE AMERICAN JOURNAL OF PATHOLOGY 2023; 193:1389-1399. [PMID: 37028592 PMCID: PMC10548273 DOI: 10.1016/j.ajpath.2023.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 03/10/2023] [Accepted: 03/27/2023] [Indexed: 04/08/2023]
Abstract
Chronic liver disease (CLD) is a major worldwide public health threat, with an estimated prevalence of 1.5 billion individuals with CLD in 2020. Chronic activation of endoplasmic reticulum (ER) stress-related pathways is recognized as substantially contributing to the pathologic progression of CLD. The ER is an intracellular organelle that folds proteins into their correct three-dimensional shapes. ER-associated enzymes and chaperone proteins highly regulate this process. Perturbations in protein folding lead to misfolded or unfolded protein accumulation in the ER lumen, resulting in ER stress and concomitant activation of the unfolded protein response (UPR). The adaptive UPR is a set of signal transduction pathways evolved in mammalian cells that attempts to reestablish ER protein homeostasis by reducing protein load and increasing ER-associated degradation. However, maladaptive UPR responses in CLD occur due to prolonged UPR activation, leading to concomitant inflammation and cell death. This review assesses the current understanding of the cellular and molecular mechanisms that regulate ER stress and the UPR in the progression of various liver diseases and the potential pharmacologic and biological interventions that target the UPR.
Collapse
Affiliation(s)
- Kaitlyn G Jackson
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - Grayson W Way
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, Virginia; Center for Clinical and Translational Research, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - Jing Zeng
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, Virginia; Department of Gastroenterology, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Marissa K Lipp
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - Huiping Zhou
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, Virginia; Central Virginia Veterans Healthcare System, Richmond, Virginia.
| |
Collapse
|
12
|
Catalani E, Del Quondam S, Brunetti K, Cherubini A, Bongiorni S, Taddei AR, Zecchini S, Giovarelli M, De Palma C, Perrotta C, Clementi E, Prantera G, Cervia D. Neuroprotective role of plumbagin on eye damage induced by high-sucrose diet in adult fruit fly Drosophila melanogaster. Biomed Pharmacother 2023; 166:115298. [PMID: 37597318 DOI: 10.1016/j.biopha.2023.115298] [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: 06/23/2023] [Revised: 08/03/2023] [Accepted: 08/05/2023] [Indexed: 08/21/2023] Open
Abstract
The natural compound plumbagin has a wide range of pharmacological and potential therapeutic activities, although its role in neuroretina degeneration is unknown. Here we evaluated the effects of plumbagin on retina homeostasis of the fruit fly Drosophila melanogaster fed with high glucose diet, a model of hyperglycemia-induced eye impairment to study the pathophysiology of diabetic retinopathy at the early stages. To this aim, the visual system of flies orally administered with plumbagin has been analyzed at structural, functional, and molecular/cellular level as for instance neuronal apoptosis/autophagy dysregulation and oxidative stress-related signals. Our results demonstrated that plumbagin ameliorates the visual performance of hyperglycemic flies. Drosophila eye-structure, clearly altered by hyperglycemia, i.e. defects of the pattern of ommatidia, irregular rhabdomeres, vacuoles, damaged mitochondria, and abnormal phototransduction units were rescued, at least in part, by plumbagin. In addition, it reactivated autophagy, decreased the presence of cell death/apoptotic features, and exerted antioxidant effects in the retina. In terms of mechanisms favoring death/survival ratio, Nrf2 signaling activation may be one of the strategies by which plumbagin reduced redox unbalance mainly increasing the levels of glutathione-S-transferase. Likewise, plumbagin may act additively and/or synergistically inhibiting the mitochondrial-endoplasmic reticulum stress and unfolded protein response pathways, which prevented neuronal impairment and eye damage induced by reactive oxygen species. These results provide an avenue for further studies, which may be helpful to develop novel therapeutic candidates and drug targets against eye neurotoxicity by high glucose, a key aspect in retinal complications of diabetes.
Collapse
Affiliation(s)
- Elisabetta Catalani
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Simona Del Quondam
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Kashi Brunetti
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Agnese Cherubini
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Silvia Bongiorni
- Department of Ecological and Biological Sciences (DEB), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Anna Rita Taddei
- Section of Electron Microscopy, Great Equipment Center, Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Silvia Zecchini
- Department of Biomedical and Clinical Sciences (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157 Milano, Italy
| | - Matteo Giovarelli
- Department of Biomedical and Clinical Sciences (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157 Milano, Italy
| | - Clara De Palma
- Department of Medical Biotechnology and Translational Medicine (BioMeTra), Università degli Studi di Milano, via L. Vanvitelli 32, 20129 Milano, Italy
| | - Cristiana Perrotta
- Department of Biomedical and Clinical Sciences (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157 Milano, Italy
| | - Emilio Clementi
- Department of Biomedical and Clinical Sciences (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157 Milano, Italy; Scientific Institute IRCCS "Eugenio Medea", via Don Luigi Monza 20, 23842 Bosisio Parini, Italy
| | - Giorgio Prantera
- Department of Ecological and Biological Sciences (DEB), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Davide Cervia
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy.
| |
Collapse
|
13
|
Xue Y, Lu F, Chang Z, Li J, Gao Y, Zhou J, Luo Y, Lai Y, Cao S, Li X, Zhou Y, Li Y, Tan Z, Cheng X, Li X, Chen J, Wang W. Intermittent dietary methionine deprivation facilitates tumoral ferroptosis and synergizes with checkpoint blockade. Nat Commun 2023; 14:4758. [PMID: 37553341 PMCID: PMC10409767 DOI: 10.1038/s41467-023-40518-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 07/27/2023] [Indexed: 08/10/2023] Open
Abstract
Dietary methionine interventions are beneficial to apoptosis-inducing chemotherapy and radiotherapy for cancer, while their effects on ferroptosis-targeting therapy and immunotherapy are unknown. Here we show the length of time methionine deprivation affects tumoral ferroptosis differently. Prolonged methionine deprivation prevents glutathione (GSH) depletion from exceeding the death threshold by blocking cation transport regulator homolog 1 (CHAC1) protein synthesis. Whereas, short-term methionine starvation accelerates ferroptosis by stimulating CHAC1 transcription. In vivo, dietary methionine with intermittent but not sustained deprivation augments tumoral ferroptosis. Intermittent methionine deprivation also sensitizes tumor cells against CD8+ T cell-mediated cytotoxicity and synergize checkpoint blockade therapy by CHAC1 upregulation. Clinically, tumor CHAC1 correlates with clinical benefits and improved survival in cancer patients treated with checkpoint blockades. Lastly, the triple combination of methionine intermittent deprivation, system xc- inhibitor and PD-1 blockade shows superior antitumor efficacy. Thus, intermittent methionine deprivation is a promising regimen to target ferroptosis and augment cancer immunotherapy.
Collapse
Affiliation(s)
- Ying Xue
- Department of Immunology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fujia Lu
- Department of Immunology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhenzhen Chang
- Department of Immunology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jing Li
- Department of Immunology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuan Gao
- Department of Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jie Zhou
- Department of Immunology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ying Luo
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yongfeng Lai
- Department of Immunology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Siyuan Cao
- Department of Immunology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoxiao Li
- Department of Immunology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuhan Zhou
- Department of Immunology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yan Li
- Department of Immunology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zheng Tan
- Department of Immunology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiang Cheng
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiong Li
- Department of Gynecology & Obstetrics, the Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jing Chen
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Weimin Wang
- Department of Immunology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
- Cell Architecture Research Institute, Huazhong University of Science and Technology, Wuhan, China.
- Key Laboratory of Organ Transplantation, Ministry of Education; NHC Key Laboratory of Organ Transplantation; Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Wuhan, China.
| |
Collapse
|
14
|
Bukhari SIA, Truesdell SS, Datta C, Choudhury P, Wu KQ, Shrestha J, Maharjan R, Plotsker E, Elased R, Laisa S, Bhambhani V, Lin Y, Kreuzer J, Morris R, Koh SB, Ellisen LW, Haas W, Ly A, Vasudevan S. Regulation of RNA methylation by therapy treatment, promotes tumor survival. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.19.540602. [PMID: 37292633 PMCID: PMC10245743 DOI: 10.1101/2023.05.19.540602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Our data previously revealed that chemosurviving cancer cells translate specific genes. Here, we find that the m6A-RNA-methyltransferase, METTL3, increases transiently in chemotherapy-treated breast cancer and leukemic cells in vitro and in vivo. Consistently, m6A increases on RNA from chemo-treated cells, and is needed for chemosurvival. This is regulated by eIF2α phosphorylation and mTOR inhibition upon therapy treatment. METTL3 mRNA purification reveals that eIF3 promotes METTL3 translation that is reduced by mutating a 5'UTR m6A-motif or depleting METTL3. METTL3 increase is transient after therapy treatment, as metabolic enzymes that control methylation and thus m6A levels on METTL3 RNA, are altered over time after therapy. Increased METTL3 reduces proliferation and anti-viral immune response genes, and enhances invasion genes, which promote tumor survival. Consistently, overriding phospho-eIF2α prevents METTL3 elevation, and reduces chemosurvival and immune-cell migration. These data reveal that therapy-induced stress signals transiently upregulate METTL3 translation, to alter gene expression for tumor survival.
Collapse
Affiliation(s)
- Syed IA Bukhari
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Samuel S Truesdell
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Chandreyee Datta
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Pritha Choudhury
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Keith Q Wu
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Jitendra Shrestha
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Ruby Maharjan
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Ethan Plotsker
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Ramzi Elased
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Sadia Laisa
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Vijeta Bhambhani
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Yue Lin
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Johannes Kreuzer
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Robert Morris
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Siang-Boon Koh
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Leif W. Ellisen
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Wilhelm Haas
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Amy Ly
- Department of Pathology, Massachusetts General Hospital, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| | - Shobha Vasudevan
- Massachusetts General Hospital Cancer Center, Department of Medicine, Massachusetts General Brigham and Harvard Medical School, Boston, MA 02114
| |
Collapse
|
15
|
Zhao N, Li N, Wang T. PERK prevents rhodopsin degradation during retinitis pigmentosa by inhibiting IRE1-induced autophagy. J Cell Biol 2023; 222:e202208147. [PMID: 37022709 PMCID: PMC10082367 DOI: 10.1083/jcb.202208147] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 01/04/2023] [Accepted: 02/14/2023] [Indexed: 04/07/2023] Open
Abstract
Chronic endoplasmic reticulum (ER) stress is the underlying cause of many degenerative diseases, including autosomal dominant retinitis pigmentosa (adRP). In adRP, mutant rhodopsins accumulate and cause ER stress. This destabilizes wild-type rhodopsin and triggers photoreceptor cell degeneration. To reveal the mechanisms by which these mutant rhodopsins exert their dominant-negative effects, we established an in vivo fluorescence reporter system to monitor mutant and wild-type rhodopsin in Drosophila. By performing a genome-wide genetic screen, we found that PERK signaling plays a key role in maintaining rhodopsin homeostasis by attenuating IRE1 activities. Degradation of wild-type rhodopsin is mediated by selective autophagy of ER, which is induced by uncontrolled IRE1/XBP1 signaling and insufficient proteasome activities. Moreover, upregulation of PERK signaling prevents autophagy and suppresses retinal degeneration in the adRP model. These findings establish a pathological role for autophagy in this neurodegenerative condition and indicate that promoting PERK activity could be used to treat ER stress-related neuropathies, including adRP.
Collapse
Affiliation(s)
- Ning Zhao
- Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Ning Li
- College of Biological Sciences, China Agricultural University, Beijing, China
| | - Tao Wang
- Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
- College of Biological Sciences, China Agricultural University, Beijing, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
- National Institute of Biological Sciences, Beijing, China
| |
Collapse
|
16
|
Lu Z, Bae EA, Verginadis II, Zhang H, Cho C, McBrearty N, George SS, Diehl JA, Koumenis C, Bradley LM, Fuchs SY. Induction of the activating transcription factor-4 in the intratumoral CD8+ T cells sustains their viability and anti-tumor activities. Cancer Immunol Immunother 2023; 72:815-826. [PMID: 36063172 PMCID: PMC10317204 DOI: 10.1007/s00262-022-03286-2] [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: 03/14/2022] [Accepted: 08/23/2022] [Indexed: 10/14/2022]
Abstract
Immune suppressive factors of the tumor microenvironment (TME) undermine viability and exhaust the activities of the intratumoral cytotoxic CD8 + T lymphocytes (CTL) thereby evading anti-tumor immunity and decreasing the benefits of immune therapies. To counteract this suppression and improve the efficacy of therapeutic regimens, it is important to identify and understand the critical regulators within CD8 + T cells that respond to TME stress and tumor-derived factors. Here we investigated the regulation and importance of activating transcription factor-4 (ATF4) in CTL using a novel Atf4ΔCD8 mouse model lacking ATF4 specifically in CD8 + cells. Induction of ATF4 in CD8 + T cells occurred in response to antigenic stimulation and was further increased by exposure to tumor-derived factors and TME conditions. Under these conditions, ATF4 played a critical role in the maintenance of survival and activities of CD8 + T cells. Conversely, selective ablation of ATF4 in CD8 + T cells in mice rendered these Atf4ΔCD8 hosts prone to accelerated growth of implanted tumors. Intratumoral ATF4-deficient CD8 + T cells were under-represented compared to wild-type counterparts and exhibited impaired activation and increased apoptosis. These findings identify ATF4 as an important regulator of viability and activity of CD8 + T cells in the TME and argue for caution in using agents that could undermine these functions of ATF4 for anti-cancer therapies.
Collapse
Affiliation(s)
- Zhen Lu
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, 380 S. University Ave, Hill 316, Philadelphia, PA, 19104, USA
| | - Eun-Ah Bae
- Aging, Cancer, and Immuno-Oncology Program, NCI Designated Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Ioannis I Verginadis
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Hongru Zhang
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, 380 S. University Ave, Hill 316, Philadelphia, PA, 19104, USA
| | - Christina Cho
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, 380 S. University Ave, Hill 316, Philadelphia, PA, 19104, USA
| | - Noreen McBrearty
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, 380 S. University Ave, Hill 316, Philadelphia, PA, 19104, USA
| | - Subin S George
- Institute for Biomedical Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - J Alan Diehl
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Constantinos Koumenis
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Linda M Bradley
- Aging, Cancer, and Immuno-Oncology Program, NCI Designated Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Serge Y Fuchs
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, 380 S. University Ave, Hill 316, Philadelphia, PA, 19104, USA.
| |
Collapse
|
17
|
Shao Y, Xu Y, Di H, Shi X, Wang Y, Liu H, Song L. The inhibition of ORMDL3 prevents Alzheimer's disease through ferroptosis by PERK/ATF4/HSPA5 pathway. IET Nanobiotechnol 2023; 17:182-196. [PMID: 36680386 DOI: 10.1049/nbt2.12113] [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: 10/28/2022] [Revised: 12/26/2022] [Accepted: 12/28/2022] [Indexed: 01/22/2023] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease with high incidence and widespread attention. There is currently no clear clarification of the pathogenesis. However, ORMDL3 causes ferroptosis in AD, and the potential mechanisms remain unclear. So, this study explore the function of ORMDL3 on ferroptosis in AD and its potential regulatory mechanisms. APPswe/PS1dE9 mice and C57BL/6 mice were induced into the mice model. The murine microglial BV-2 cells also were induced into the vitro model. In serum samples of AD patients, ORMDL3 mRNA expression levels were upregulated. The serum ORMDL3 levels expression was positively related to the ADL score or MoCA score in AD patients. The serum ORMDL3 expression level was positively related to MMSE score or Hcy levels in AD patients. The mRNA expression of ORMDL3 in the hippocampal tissue of the mice model of AD was upregulated at one, four and eight months. The protein expression of ORMDL3 was upregulated in the mice model of AD. ORMDL3 promoted Alzheimer's disease, and increased oxidative response and ferroptosis in a model of AD. PERK/ATF4/HSPA5 pathway is one important signal pathway for the effects of ORMDL3 in a model of AD. Collectively, these data suggested that ORMDL3 promoted oxidative response and ferroptosis in a model of AD by the PERK/ATF4/HSPA5 pathway, which might be a novel target spot mechanism of ferroptosis in AD and may serve as a regulator of AD-induced ferroptosis.
Collapse
Affiliation(s)
- Yankun Shao
- Department of Neurology, China-Japan Union Hospital of JiLin University, Changchun, China
| | - Yilin Xu
- Department of Neurology, China-Japan Union Hospital of JiLin University, Changchun, China
| | - Huang Di
- Department of Neurology, China-Japan Union Hospital of JiLin University, Changchun, China
| | - Xinxiu Shi
- Department of Neurology, China-Japan Union Hospital of JiLin University, Changchun, China
| | - Yingying Wang
- Department of Neurology, China-Japan Union Hospital of JiLin University, Changchun, China
| | - Hongyu Liu
- Department of Neurology, China-Japan Union Hospital of JiLin University, Changchun, China
| | - Lina Song
- Department of Neurology, China-Japan Union Hospital of JiLin University, Changchun, China
| |
Collapse
|
18
|
Fernandez SG, Ferguson L, Ingolia NT. Ribosome rescue factor PELOTA modulates translation start site choice and protein isoform levels of transcription factor C/EBP α. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.16.524343. [PMID: 36711859 PMCID: PMC9882168 DOI: 10.1101/2023.01.16.524343] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Translation initiation at alternative start sites can dynamically control the synthesis of two or more functionally distinct protein isoforms from a single mRNA. Alternate isoforms of the hematopoietic transcription factor CCAAT-enhancer binding protein α (C/EBPα) produced from different start sites exert opposing effects during myeloid cell development. This alternative initiation depends on sequence features of the CEBPA transcript, including a regulatory upstream open reading frame (uORF), but the molecular basis is not fully understood. Here we identify trans-acting factors that affect C/EBPα isoform choice using a sensitive and quantitative two-color fluorescence reporter coupled with CRISPRi screening. Our screen uncovered a role for the ribosome rescue factor PELOTA (PELO) in promoting expression of the longer C/EBPα isoform, by directly removing inhibitory unrecycled ribosomes and through indirect effects mediated by the mechanistic target of rapamycin (mTOR) kinase. Our work provides further mechanistic insights into coupling between ribosome recycling and translation reinitiation in regulation of a key transcription factor, with implications for normal hematopoiesis and leukemiagenesis.
Collapse
Affiliation(s)
| | - Lucas Ferguson
- Department of Molecular and Cell Biology, University of California, Berkeley
| | - Nicholas T. Ingolia
- Department of Molecular and Cell Biology, University of California, Berkeley
- Center for Computational Biology and California Institute for Quantitative Biosciences, University of California, Berkeley
| |
Collapse
|
19
|
Dobrinskikh E, Hennessy CE, Kurche JS, Kim E, Estrella AM, Cardwell J, Yang IV, Schwartz DA. Epithelial Endoplasmic Reticulum Stress Enhances the Risk of Muc5b-associated Lung Fibrosis. Am J Respir Cell Mol Biol 2023; 68:62-74. [PMID: 36108173 PMCID: PMC9817917 DOI: 10.1165/rcmb.2022-0252oc] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Accepted: 09/15/2022] [Indexed: 02/05/2023] Open
Abstract
The gain-of-function minor allele of the MUC5B (mucin 5B, oligomeric mucus/gel-forming) promoter (rs35705950) is the strongest risk factor for idiopathic pulmonary fibrosis (IPF), a devastating fibrotic lung disease that leads to progressive respiratory failure in adults. We have previously demonstrated that Muc5b overexpression in mice worsens lung fibrosis after bleomycin exposure and have hypothesized that excess Muc5b promotes endoplasmic reticulum (ER) stress and apoptosis, stimulating fibrotic lung injury. Here, we report that ER stress pathway members ATF4 (activating transcription factor 4) and ATF6 coexpress with MUC5B in epithelia of the distal IPF airway and honeycomb cyst and that this is more pronounced in carriers of the gain-of-function MUC5B promoter variant. Similarly, in mice exposed to bleomycin, Muc5b expression is temporally associated with markers of ER stress. Using bulk and single-cell RNA sequencing in bleomycin-exposed mice, we found that pathologic ER stress-associated transcripts Atf4 and Ddit3 (DNA damage inducible transcript 3) were elevated in alveolar epithelia of SFTPC-Muc5b transgenic (SFTPC-Muc5bTg) mice relative to wild-type (WT) mice. Activation of the ER stress response inhibits protein translation for most genes by phosphorylation of Eif2α (eukaryotic translation initiation factor 2 alpha), which prevents guanine exchange by Eif2B and facilitates translation of Atf4. The integrated stress response inhibitor (ISRIB) facilitates interaction of phosphorylated Eif2α with Eif2B, overcoming translation inhibition associated with ER stress and reducing Atf4. We found that a single dose of ISRIB diminished Atf4 translation in SFTPC-Muc5bTg mice after bleomycin injury. Moreover, ISRIB resolved the exaggerated fibrotic response of SFTPC-Muc5bTg mice to bleomycin. In summary, we demonstrate that MUC5B and Muc5b expression is associated with pathologic ER stress and that restoration of normal translation with a single dose of ISRIB promotes lung repair in bleomycin-injured Muc5b-overexpressing mice.
Collapse
Affiliation(s)
| | | | - Jonathan S. Kurche
- Department of Medicine
- Pulmonary Section, Rocky Mountain Regional Veterans Affairs Medical Center, Aurora, Colorado
| | | | - Alani M. Estrella
- Roy and Diana Vagelos College of Physicians and Surgeons, Columbia University Medical Center, New York, New York; and
| | | | - Ivana V. Yang
- Department of Medicine
- Department of Epidemiology, Colorado School of Public Health, Aurora, Colorado
| | - David A. Schwartz
- Department of Medicine
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado
| |
Collapse
|
20
|
DAP5 enables main ORF translation on mRNAs with structured and uORF-containing 5' leaders. Nat Commun 2022; 13:7510. [PMID: 36473845 PMCID: PMC9726905 DOI: 10.1038/s41467-022-35019-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 11/16/2022] [Indexed: 12/12/2022] Open
Abstract
Half of mammalian transcripts contain short upstream open reading frames (uORFs) that potentially regulate translation of the downstream coding sequence (CDS). The molecular mechanisms governing these events remain poorly understood. Here, we find that the non-canonical initiation factor Death-associated protein 5 (DAP5 or eIF4G2) is required for translation initiation on select transcripts. Using ribosome profiling and luciferase-based reporters coupled with mutational analysis we show that DAP5-mediated translation occurs on messenger RNAs (mRNAs) with long, structure-prone 5' leader sequences and persistent uORF translation. These mRNAs preferentially code for signalling factors such as kinases and phosphatases. We also report that cap/eIF4F- and eIF4A-dependent recruitment of DAP5 to the mRNA facilitates main CDS, but not uORF, translation suggesting a role for DAP5 in translation re-initiation. Our study reveals important mechanistic insights into how a non-canonical translation initiation factor involved in stem cell fate shapes the synthesis of specific signalling factors.
Collapse
|
21
|
Green KM, Miller SL, Malik I, Todd PK. Non-canonical initiation factors modulate repeat-associated non-AUG translation. Hum Mol Genet 2022; 31:2521-2534. [PMID: 35220421 PMCID: PMC9618161 DOI: 10.1093/hmg/ddac021] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 12/28/2021] [Accepted: 01/14/2022] [Indexed: 11/14/2022] Open
Abstract
Repeat-associated non-AUG (RAN) translation of expanded repeat-mutation mRNA produces toxic peptides in neurons of patients suffering from neurodegenerative diseases. Recent findings indicate that RAN translation in diverse model systems is not inhibited by cellular stressors that impair global translation through phosphorylation of the alpha subunit of eIF2, the essential eukaryotic translation initiation factor that brings the initiator tRNA to the 40S ribosome. Using in vitro, cell-based and Drosophila models, we examined the role of alternative ternary complex factors that may function in place of eIF2, including eIF2A, eIF2D, DENR and MCTS1. Among these factors, DENR knockdown had the greatest inhibitory effect on RAN translation of expanded GGGGCC and CGG repeat reporters and its reduction improved the survival of Drosophila expressing expanded GGGGCC repeats. Taken together, these data support a role for alternative initiation factors in RAN translation and suggest these may serve as novel therapeutic targets in neurodegenerative disease.
Collapse
Affiliation(s)
- Katelyn M Green
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Shannon L Miller
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Indranil Malik
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
- VA Ann Arbor Healthcare System, Ann Arbor, MI, USA
| |
Collapse
|
22
|
Xiao W, Sun Y, Xu J, Zhang N, Dong L. uORF-Mediated Translational Regulation of ATF4 Serves as an Evolutionarily Conserved Mechanism Contributing to Non-Small-Cell Lung Cancer (NSCLC) and Stress Response. J Mol Evol 2022; 90:375-388. [PMID: 35962830 PMCID: PMC9375200 DOI: 10.1007/s00239-022-10068-y] [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] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 07/20/2022] [Indexed: 11/30/2022]
Abstract
Diseases and environmental stresses are two distinct challenges for virtually all living organisms. In light of evolution, cellular responses to diseases and stresses might share similar molecular mechanisms, but the detailed regulation pathway is not reported yet. We obtained the transcriptomes and translatomes from several NSCLC (non-small-cell lung cancer) patients as well as from different species under normal or stress conditions. We found that the translation level of gene ATF4 is remarkably enhanced in NSCLC due to the reduced number of ribosomes binding to its upstream open reading frames (uORFs). We also showed the evolutionary conservation of this uORF-ATF4 regulation in the stress response of other species. Molecular experiments showed that knockdown of ATF4 reduced the cell growth rate while overexpression of ATF4 enhanced cell growth, especially for the ATF4 allele with mutated uORFs. Population genetics analyses in multiple species verified that the mutations that abolish uATGs (start codon of uORFs) are highly deleterious, suggesting the functional importance of uORFs. Our study proposes an evolutionarily conserved pattern that enhances the ATF4 translation by uORFs upon stress or disease. We generalized the concept of cellular response to diseases and stresses. These two biological processes may share similar molecular mechanisms.
Collapse
Affiliation(s)
- Wenjing Xiao
- Department of Radiotherapy, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China.
| | - Yang Sun
- Department of Radiotherapy, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Jinpeng Xu
- Department of Radiotherapy, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Na Zhang
- Department of Radiotherapy, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Lina Dong
- Department of Radiotherapy, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| |
Collapse
|
23
|
Yerlikaya A. Heme-regulated inhibitor: an overlooked eIF2α kinase in cancer investigations. Med Oncol 2022; 39:73. [PMID: 35568791 DOI: 10.1007/s12032-022-01668-1] [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: 12/30/2021] [Accepted: 01/24/2022] [Indexed: 10/18/2022]
Abstract
Heme-regulated inhibitor (HRI) kinase is a serine-threonine kinase, controlling the initiation of protein synthesis via phosphorylating α subunit of eIF2 on serine 51 residue, mainly in response to heme deprivation in erythroid cells. However, recent studies showed that HRI is also activated by several diverse signals, causing dysregulations in intracellular homeostatic mechanisms in non-erythroid cells. For instance, it was reported that the decrease in protein synthesis upon the 26S proteasomal inhibition by MG132 or bortezomib is mediated by increased eIF2α phosphorylation in an HRI-dependent manner in mouse embryonic fibroblast cells. The increase in eIF2α phosphorylation level through the activation of HRI upon 26S proteasomal inhibition is believed to protect cells against the buildup of misfolded and ubiquitinated proteins, having the potential to trigger the apoptotic response. In contrast, prolonged and sustained HRI-mediated eIF2α phosphorylation can induce cell death, which may involve ATF4 and CHOP expression. Altogether, these studies suggest that HRI-mediated eIF2α phosphorylation may be cytoprotective or cytotoxic depending on the cells, type, and duration of pharmacological agents used. It is thus hypothesized that both HRI activators, inducing eIF2α phosphorylation or HRI inhibitors causing disturbances in eIF2α phosphorylation, may be effective as novel strategies in cancer treatment if the balance in eIF2α phosphorylation is shifted in favor of autophagic or apoptotic response in cancer cells. It is here aimed to review the role of HRI in various biological mechanisms as well as the therapeutic potentials of recently developed HRI activators and inhibitors, targeting eIF2α phosphorylation in cancer cells.
Collapse
Affiliation(s)
- Azmi Yerlikaya
- Department of Medical Biology, Faculty of Medicine, Kutahya Health Sciences University, Kutahya, Turkey.
| |
Collapse
|
24
|
Wang G, Fan Y, Cao P, Tan K. Insight into the mitochondrial unfolded protein response and cancer: opportunities and challenges. Cell Biosci 2022; 12:18. [PMID: 35180892 PMCID: PMC8857832 DOI: 10.1186/s13578-022-00747-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 01/18/2022] [Indexed: 02/08/2023] Open
Abstract
The mitochondrial unfolded protein response (UPRmt) is an evolutionarily conserved protective transcriptional response that maintains mitochondrial proteostasis by inducing the expression of mitochondrial chaperones and proteases in response to various stresses. The UPRmt-mediated transcriptional program requires the participation of various upstream signaling pathways and molecules. The factors regulating the UPRmt in Caenorhabditis elegans (C. elegans) and mammals are both similar and different. Cancer cells, as malignant cells with uncontrolled proliferation, are exposed to various challenges from endogenous and exogenous stresses. Therefore, in cancer cells, the UPRmt is hijacked and exploited for the repair of mitochondria and the promotion of tumor growth, invasion and metastasis. In this review, we systematically introduce the inducers of UPRmt, the biological processes in which UPRmt participates, the mechanisms regulating the UPRmt in C. elegans and mammals, cross-tissue signal transduction of the UPRmt and the roles of the UPRmt in promoting cancer initiation and progression. Disrupting proteostasis in cancer cells by targeting UPRmt constitutes a novel anticancer therapeutic strategy.
Collapse
Affiliation(s)
- Ge Wang
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Sciences, Hebei Normal University, Hebei, 050024, China.,Department of Human Anatomy, Histology and Embryology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), State Key Laboratory of Natural and Biomimetic Drugs, Peking University Health Science Center, Beijing, 100191, China
| | - Yumei Fan
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Sciences, Hebei Normal University, Hebei, 050024, China
| | - Pengxiu Cao
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Sciences, Hebei Normal University, Hebei, 050024, China
| | - Ke Tan
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Sciences, Hebei Normal University, Hebei, 050024, China.
| |
Collapse
|
25
|
Young DJ, Guydosh NR. Rebirth of the translational machinery: The importance of recycling ribosomes. Bioessays 2022; 44:e2100269. [PMID: 35147231 PMCID: PMC9270684 DOI: 10.1002/bies.202100269] [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: 11/10/2021] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 11/10/2022]
Abstract
Translation of the genetic code occurs in a cycle where ribosomes engage mRNAs, synthesize protein, and then disengage in order to repeat the process again. The final part of this process-ribosome recycling, where ribosomes dissociate from mRNAs-involves a complex molecular choreography of specific protein factors to remove the large and small subunits of the ribosome in a coordinated fashion. Errors in this process can lead to the accumulation of ribosomes at stop codons or translation of downstream open reading frames (ORFs). Ribosome recycling is also critical when a ribosome stalls during the elongation phase of translation and must be rescued to allow continued translation of the mRNA. Here we discuss the molecular interactions that drive ribosome recycling, and their regulation in the cell. We also examine the consequences of inefficient recycling with regards to disease, and its functional roles in synthesis of novel peptides, regulation of gene expression, and control of mRNA-associated proteins. Alterations in ribosome recycling efficiency have the potential to impact many cellular functions but additional work is needed to understand how this regulatory power is utilized.
Collapse
Affiliation(s)
- David J Young
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Nicholas R Guydosh
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| |
Collapse
|
26
|
Clemm von Hohenberg K, Müller S, Schleich S, Meister M, Bohlen J, Hofmann TG, Teleman AA. Cyclin B/CDK1 and Cyclin A/CDK2 phosphorylate DENR to promote mitotic protein translation and faithful cell division. Nat Commun 2022; 13:668. [PMID: 35115540 PMCID: PMC8813921 DOI: 10.1038/s41467-022-28265-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 01/12/2022] [Indexed: 12/11/2022] Open
Abstract
DENR and MCTS1 have been identified as oncogenes in several different tumor entities. The heterodimeric DENR·MCTS1 protein complex promotes translation of mRNAs containing upstream Open Reading Frames (uORFs). We show here that DENR is phosphorylated on Serine 73 by Cyclin B/CDK1 and Cyclin A/CDK2 at the onset of mitosis, and then dephosphorylated as cells exit mitosis. Phosphorylation of Ser73 promotes mitotic stability of DENR protein and prevents its cleavage at Asp26. This leads to enhanced translation of mRNAs involved in mitosis. Indeed, we find that roughly 40% of all mRNAs with elevated translation in mitosis are DENR targets. In the absence of DENR or of Ser73 phosphorylation, cells display elevated levels of aberrant mitoses and cell death. This provides a mechanism how the cell cycle regulates translation of a subset of mitotically relevant mRNAs during mitosis. The cell cycle regulates translation during mitosis by controlling DENR stability. Here, the authors show the non-canonical translation initiation complex DENR·MCTS1 is phosphorylated during mitosis by CDK1 and 2, enabling the translation of genes needed for proper mitotic progression.
Collapse
Affiliation(s)
- Katharina Clemm von Hohenberg
- German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany.,Heidelberg University, 69120, Heidelberg, Germany.,CellNetworks-Cluster of Excellence, Heidelberg University, Heidelberg, Germany.,Department of Medicine III, Universitätsmedizin Mannheim, 68167, Mannheim, Germany
| | - Sandra Müller
- German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany.,Heidelberg University, 69120, Heidelberg, Germany
| | - Sibylle Schleich
- German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany.,Heidelberg University, 69120, Heidelberg, Germany
| | - Matthias Meister
- Division of Viral Transformation Mechanisms, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Jonathan Bohlen
- German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany.,Heidelberg University, 69120, Heidelberg, Germany.,CellNetworks-Cluster of Excellence, Heidelberg University, Heidelberg, Germany.,Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Paris, France.,University of Paris, Imagine Institute, Paris, France
| | - Thomas G Hofmann
- Institute of Toxicology, University Medical Center Mainz at the Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Aurelio A Teleman
- German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany. .,Heidelberg University, 69120, Heidelberg, Germany. .,CellNetworks-Cluster of Excellence, Heidelberg University, Heidelberg, Germany.
| |
Collapse
|
27
|
Korneeva NL. Integrated Stress Response in Neuronal Pathology and in Health. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:S111-S127. [PMID: 35501991 DOI: 10.1134/s0006297922140103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 10/29/2021] [Accepted: 11/02/2021] [Indexed: 06/14/2023]
Abstract
Neurodegeneration involves progressive pathological loss of a specific population of neurons, glial activation, and dysfunction of myelinating oligodendrocytes leading to cognitive impairment and altered movement, breathing, and senses. Neuronal degeneration is a hallmark of aging, stroke, drug abuse, toxic chemical exposure, viral infection, chronic inflammation, and a variety of neurological diseases. Accumulation of intra- and extracellular protein aggregates is a common characteristic of cell pathologies. Excessive production of reactive oxygen species and nitric oxide, induction of endoplasmic reticulum stress, and accumulation of misfolded protein aggregates have been shown to trigger a defensive mechanism called integrated stress response (ISR). Activation of ISR is important for synaptic plasticity in learning and memory formation. However, sustaining of ISR may lead to the development of neuronal pathologies and altered patterns in behavior and perception.
Collapse
Affiliation(s)
- Nadejda L Korneeva
- Louisiana State University Health Science Center, Shreveport, LA 71103, USA.
| |
Collapse
|
28
|
Wistrom E, Chase R, Smith PR, Campbell ZT. A compendium of validated pain genes. WIREs Mech Dis 2022; 14:e1570. [PMID: 35760453 PMCID: PMC9787016 DOI: 10.1002/wsbm.1570] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/28/2022] [Accepted: 06/06/2022] [Indexed: 12/30/2022]
Abstract
The development of novel pain therapeutics hinges on the identification and rigorous validation of potential targets. Model organisms provide a means to test the involvement of specific genes and regulatory elements in pain. Here we provide a list of genes linked to pain-associated behaviors. We capitalize on results spanning over three decades to identify a set of 242 genes. They support a remarkable diversity of functions spanning action potential propagation, immune response, GPCR signaling, enzymatic catalysis, nucleic acid regulation, and intercellular signaling. Making use of existing tissue and single-cell high-throughput RNA sequencing datasets, we examine their patterns of expression. For each gene class, we discuss archetypal members, with an emphasis on opportunities for additional experimentation. Finally, we discuss how powerful and increasingly ubiquitous forward genetic screening approaches could be used to improve our ability to identify pain genes. This article is categorized under: Neurological Diseases > Genetics/Genomics/Epigenetics Neurological Diseases > Molecular and Cellular Physiology.
Collapse
Affiliation(s)
- Eric Wistrom
- Department of Biological SciencesUniversity of Texas at DallasRichardsonTexasUSA
| | - Rebecca Chase
- Department of Biological SciencesUniversity of Texas at DallasRichardsonTexasUSA
| | - Patrick R. Smith
- Department of Biological SciencesUniversity of Texas at DallasRichardsonTexasUSA
| | - Zachary T. Campbell
- Department of Biological SciencesUniversity of Texas at DallasRichardsonTexasUSA,Center for Advanced Pain StudiesUniversity of Texas at DallasRichardsonTexasUSA
| |
Collapse
|
29
|
Vasudevan D, Katow H, Huang HW, Tang G, Ryoo HD. A Protein-trap allele reveals roles for Drosophila ATF4 in photoreceptor degeneration, oogenesis and wing development. Dis Model Mech 2021; 15:273766. [PMID: 34919148 PMCID: PMC8938396 DOI: 10.1242/dmm.049119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 12/08/2021] [Indexed: 11/20/2022] Open
Abstract
Metazoans have evolved various quality control mechanisms to cope with cellular stress inflicted by external and physiological conditions. ATF4 is a major effector of the Integrated Stress Response (ISR), an evolutionarily conserved pathway that mediates adaptation to various cellular stressors. Loss of function of Drosophila ATF4, encoded by the gene cryptocephal (crc), results in lethality during pupal development. The roles of crc in Drosophila disease models and in adult tissue homeostasis thus remain poorly understood. Here, we report that a protein-trap MiMIC insertion in the crc locus generates a crc-GFP fusion protein that allows visualization of crc activity in vivo. This allele also acts as a hypomorphic mutant that uncovers previously unknown roles for crc. Specifically, the crc protein-trap line shows crc-GFP induction in a Drosophila model for Retinitis Pigmentosa (RP). This crc allele renders flies more vulnerable to amino acid deprivation and age-dependent retinal degeneration. These mutants also show defects in wing veins and oocyte maturation. Together, our data reveal previously unknown roles for crc in development, cellular homeostasis and photoreceptor survival.
Collapse
Affiliation(s)
- Deepika Vasudevan
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY 10016, USA.,Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Hidetaka Katow
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | | | - Grace Tang
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Hyung Don Ryoo
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY 10016, USA
| |
Collapse
|
30
|
Sonobe Y, Aburas J, Krishnan G, Fleming AC, Ghadge G, Islam P, Warren EC, Gu Y, Kankel MW, Brown AEX, Kiskinis E, Gendron TF, Gao FB, Roos RP, Kratsios P. A C. elegans model of C9orf72-associated ALS/FTD uncovers a conserved role for eIF2D in RAN translation. Nat Commun 2021; 12:6025. [PMID: 34654821 PMCID: PMC8519953 DOI: 10.1038/s41467-021-26303-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 09/28/2021] [Indexed: 12/31/2022] Open
Abstract
A hexanucleotide repeat expansion GGGGCC in the non-coding region of C9orf72 is the most common cause of inherited amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Toxic dipeptide repeats (DPRs) are synthesized from GGGGCC via repeat-associated non-AUG (RAN) translation. Here, we develop C. elegans models that express, either ubiquitously or exclusively in neurons, 75 GGGGCC repeats flanked by intronic C9orf72 sequence. The worms generate DPRs (poly-glycine-alanine [poly-GA], poly-glycine-proline [poly-GP]) and poly-glycine-arginine [poly-GR]), display neurodegeneration, and exhibit locomotor and lifespan defects. Mutation of a non-canonical translation-initiating codon (CUG) upstream of the repeats selectively reduces poly-GA steady-state levels and ameliorates disease, suggesting poly-GA is pathogenic. Importantly, loss-of-function mutations in the eukaryotic translation initiation factor 2D (eif-2D/eIF2D) reduce poly-GA and poly-GP levels, and increase lifespan in both C. elegans models. Our in vitro studies in mammalian cells yield similar results. Here, we show a conserved role for eif-2D/eIF2D in DPR expression.
Collapse
Affiliation(s)
- Yoshifumi Sonobe
- grid.412578.d0000 0000 8736 9513University of Chicago Medical Center, 5841S. Maryland Avenue, Chicago, IL 60637 USA ,grid.412578.d0000 0000 8736 9513Department of Neurology, University of Chicago Medical Center, 5841S. Maryland Avenue, Chicago, IL 60637 USA ,grid.170205.10000 0004 1936 7822The Grossman Institute for Neuroscience, Quantitative Biology, and Human Behavior, University of Chicago, Chicago, IL USA
| | - Jihad Aburas
- grid.412578.d0000 0000 8736 9513University of Chicago Medical Center, 5841S. Maryland Avenue, Chicago, IL 60637 USA ,grid.170205.10000 0004 1936 7822The Grossman Institute for Neuroscience, Quantitative Biology, and Human Behavior, University of Chicago, Chicago, IL USA ,grid.170205.10000 0004 1936 7822Department of Neurobiology, University of Chicago, Chicago, IL USA
| | - Gopinath Krishnan
- grid.168645.80000 0001 0742 0364Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Andrew C. Fleming
- grid.16753.360000 0001 2299 3507The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, USA
| | - Ghanashyam Ghadge
- grid.412578.d0000 0000 8736 9513University of Chicago Medical Center, 5841S. Maryland Avenue, Chicago, IL 60637 USA ,grid.412578.d0000 0000 8736 9513Department of Neurology, University of Chicago Medical Center, 5841S. Maryland Avenue, Chicago, IL 60637 USA ,grid.170205.10000 0004 1936 7822The Grossman Institute for Neuroscience, Quantitative Biology, and Human Behavior, University of Chicago, Chicago, IL USA
| | - Priota Islam
- grid.14105.310000000122478951MRC London Institute of Medical Sciences, London, UK ,grid.7445.20000 0001 2113 8111Institute of Clinical Sciences, Imperial College London, London, UK
| | - Eleanor C. Warren
- grid.14105.310000000122478951MRC London Institute of Medical Sciences, London, UK ,grid.7445.20000 0001 2113 8111Institute of Clinical Sciences, Imperial College London, London, UK
| | - Yuanzheng Gu
- grid.417832.b0000 0004 0384 8146Neuromuscular & Movement Disorders, Biogen, Cambridge, MA 02142 USA
| | - Mark W. Kankel
- grid.417832.b0000 0004 0384 8146Neuromuscular & Movement Disorders, Biogen, Cambridge, MA 02142 USA
| | - André E. X. Brown
- grid.14105.310000000122478951MRC London Institute of Medical Sciences, London, UK ,grid.7445.20000 0001 2113 8111Institute of Clinical Sciences, Imperial College London, London, UK
| | - Evangelos Kiskinis
- grid.16753.360000 0001 2299 3507The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, USA
| | - Tania F. Gendron
- grid.417467.70000 0004 0443 9942Department of Neuroscience, Mayo Clinic, Jacksonville, FL USA
| | - Fen-Biao Gao
- grid.168645.80000 0001 0742 0364Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Raymond P. Roos
- grid.412578.d0000 0000 8736 9513University of Chicago Medical Center, 5841S. Maryland Avenue, Chicago, IL 60637 USA ,grid.412578.d0000 0000 8736 9513Department of Neurology, University of Chicago Medical Center, 5841S. Maryland Avenue, Chicago, IL 60637 USA ,grid.170205.10000 0004 1936 7822The Grossman Institute for Neuroscience, Quantitative Biology, and Human Behavior, University of Chicago, Chicago, IL USA
| | - Paschalis Kratsios
- University of Chicago Medical Center, 5841S. Maryland Avenue, Chicago, IL, 60637, USA. .,The Grossman Institute for Neuroscience, Quantitative Biology, and Human Behavior, University of Chicago, Chicago, IL, USA. .,Department of Neurobiology, University of Chicago, Chicago, IL, USA.
| |
Collapse
|
31
|
Brown B, Mitra S, Roach FD, Vasudevan D, Ryoo HD. The transcription factor Xrp1 is required for PERK-mediated antioxidant gene induction in Drosophila. eLife 2021; 10:74047. [PMID: 34605405 PMCID: PMC8514241 DOI: 10.7554/elife.74047] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 09/27/2021] [Indexed: 12/13/2022] Open
Abstract
PERK is an endoplasmic reticulum (ER) transmembrane sensor that phosphorylates eIF2α to initiate the Unfolded Protein Response (UPR). eIF2α phosphorylation promotes stress-responsive gene expression most notably through the transcription factor ATF4 that contains a regulatory 5’ leader. Possible PERK effectors other than ATF4 remain poorly understood. Here, we report that the bZIP transcription factor Xrp1 is required for ATF4-independent PERK signaling. Cell-type-specific gene expression profiling in Drosophila indicated that delta-family glutathione-S-transferases (gstD) are prominently induced by the UPR-activating transgene Rh1G69D. Perk was necessary and sufficient for such gstD induction, but ATF4 was not required. Instead, Perk and other regulators of eIF2α phosphorylation regulated Xrp1 protein levels to induce gstDs. The Xrp1 5’ leader has a conserved upstream Open Reading Frame (uORF) analogous to those that regulate ATF4 translation. The gstD-GFP reporter induction required putative Xrp1 binding sites. These results indicate that antioxidant genes are highly induced by a previously unrecognized UPR signaling axis consisting of PERK and Xrp1.
Collapse
Affiliation(s)
- Brian Brown
- NYU Grossman School of Medicine, New York, United States
| | - Sahana Mitra
- NYU Grossman School of Medicine, New York, United States
| | | | | | - Hyung Don Ryoo
- NYU Grossman School of Medicine, New York, United States
| |
Collapse
|
32
|
English AM, Green KM, Moon SL. A (dis)integrated stress response: Genetic diseases of eIF2α regulators. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 13:e1689. [PMID: 34463036 DOI: 10.1002/wrna.1689] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 08/03/2021] [Accepted: 08/04/2021] [Indexed: 01/28/2023]
Abstract
The integrated stress response (ISR) is a conserved mechanism by which eukaryotic cells remodel gene expression to adapt to intrinsic and extrinsic stressors rapidly and reversibly. The ISR is initiated when stress-activated protein kinases phosphorylate the major translation initiation factor eukaryotic translation initiation factor 2ɑ (eIF2ɑ), which globally suppresses translation initiation activity and permits the selective translation of stress-induced genes including important transcription factors such as activating transcription factor 4 (ATF4). Translationally repressed messenger RNAs (mRNAs) and noncoding RNAs assemble into cytoplasmic RNA-protein granules and polyadenylated RNAs are concomitantly stabilized. Thus, regulated changes in mRNA translation, stability, and localization to RNA-protein granules contribute to the reprogramming of gene expression that defines the ISR. We discuss fundamental mechanisms of RNA regulation during the ISR and provide an overview of a growing class of genetic disorders associated with mutant alleles of key translation factors in the ISR pathway. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA in Disease and Development > RNA in Disease Translation > Translation Regulation RNA in Disease and Development > RNA in Development.
Collapse
Affiliation(s)
- Alyssa M English
- Department of Human Genetics, Center for RNA Biomedicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Katelyn M Green
- Department of Chemistry, Department of Human Genetics, Center for RNA Biomedicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Stephanie L Moon
- Department of Human Genetics, Center for RNA Biomedicine, University of Michigan, Ann Arbor, Michigan, USA
| |
Collapse
|
33
|
Peterson C, Kim YC, Ensign LM, Jun AS, Foster J. Induction of the integrated stress response in the rat cornea. Exp Eye Res 2021; 210:108722. [PMID: 34370978 DOI: 10.1016/j.exer.2021.108722] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 07/13/2021] [Accepted: 08/05/2021] [Indexed: 11/19/2022]
Abstract
Keratoconus (KC), a progressive, degenerative corneal disease, represents the second leading indication for corneal transplantation globally. We have previously demonstrated that components of the Integrated Stress Response (ISR) are upregulated in human keratoconic donor tissue, and treatment of normal tissue with ISR agonists attenuates collagen production. With no consistently accepted animal models available for translational KC research, we sought to establish an in vivo model based on ISR activation to elucidate its role in the development of the KC phenotype. Four-week-old female SD rats were treated with topical SAL003 formulated as a nanosuspension or vehicle every 48 h for four doses. Animals were subject to monitoring for ocular inflammation and discomfort before being euthanized at 1, 14, or 28 days after treatment was withdrawn. Schirmer's tear test, intraocular pressure, and body weight measurements were obtained at baseline and prior to euthanasia. Globes were subject to routine histopathology, immunohistochemistry for ATF4, and qPCR for Col1a1 expression. ANOVAs and Student's t tests were used to assess statistical significance (α = 0.05). SAL003 treatment did not produce any adverse ocular or systemic phenotype but did result in decreased keratocyte density. Col1a1 transcripts were reduced, corresponding to nuclear ATF4 expression within the axial cornea. In vivo topical treatment with a gel-formulated ISR agonist recapitulates key features of the activated ISR including nuclear ATF4 expression and decreased extracellular matrix (ECM) production. Exogenous ISR agonists may present one approach to establishing a rodent model for keratoconus, a charge essential for future evaluations of pathogenesis and therapeutic interventions.
Collapse
Affiliation(s)
- C Peterson
- Department of Molecular & Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Y C Kim
- Center for Nanomedicine at the Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - L M Ensign
- Center for Nanomedicine at the Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - A S Jun
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - J Foster
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| |
Collapse
|
34
|
Alghoul F, Laure S, Eriani G, Martin F. Translation inhibitory elements from Hoxa3 and Hoxa11 mRNAs use uORFs for translation inhibition. eLife 2021; 10:e66369. [PMID: 34076576 PMCID: PMC8172242 DOI: 10.7554/elife.66369] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 05/20/2021] [Indexed: 01/20/2023] Open
Abstract
During embryogenesis, Hox mRNA translation is tightly regulated by a sophisticated molecular mechanism that combines two RNA regulons located in their 5'UTR. First, an internal ribosome entry site (IRES) enables cap-independent translation. The second regulon is a translation inhibitory element or TIE, which ensures concomitant cap-dependent translation inhibition. In this study, we deciphered the molecular mechanisms of mouse Hoxa3 and Hoxa11 TIEs. Both TIEs possess an upstream open reading frame (uORF) that is critical to inhibit cap-dependent translation. However, the molecular mechanisms used are different. In Hoxa3 TIE, we identify an uORF which inhibits cap-dependent translation and we show the requirement of the non-canonical initiation factor eIF2D for this process. The mode of action of Hoxa11 TIE is different, it also contains an uORF but it is a minimal uORF formed by an uAUG followed immediately by a stop codon, namely a 'start-stop'. The 'start-stop' sequence is species-specific and in mice, is located upstream of a highly stable stem loop structure which stalls the 80S ribosome and thereby inhibits cap-dependent translation of Hoxa11 main ORF.
Collapse
Affiliation(s)
- Fatima Alghoul
- Institut de Biologie Moléculaire et Cellulaire, “Architecture et Réactivité de l’ARN” CNRS UPR9002, Université de StrasbourgStrasbourgFrance
| | - Schaeffer Laure
- Institut de Biologie Moléculaire et Cellulaire, “Architecture et Réactivité de l’ARN” CNRS UPR9002, Université de StrasbourgStrasbourgFrance
| | - Gilbert Eriani
- Institut de Biologie Moléculaire et Cellulaire, “Architecture et Réactivité de l’ARN” CNRS UPR9002, Université de StrasbourgStrasbourgFrance
| | - Franck Martin
- Institut de Biologie Moléculaire et Cellulaire, “Architecture et Réactivité de l’ARN” CNRS UPR9002, Université de StrasbourgStrasbourgFrance
| |
Collapse
|
35
|
Young DJ, Meydan S, Guydosh NR. 40S ribosome profiling reveals distinct roles for Tma20/Tma22 (MCT-1/DENR) and Tma64 (eIF2D) in 40S subunit recycling. Nat Commun 2021; 12:2976. [PMID: 34016977 PMCID: PMC8137927 DOI: 10.1038/s41467-021-23223-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 04/14/2021] [Indexed: 12/21/2022] Open
Abstract
The recycling of ribosomes at stop codons for use in further rounds of translation is critical for efficient protein synthesis. Removal of the 60S subunit is catalyzed by the ATPase Rli1 (ABCE1) while removal of the 40S is thought to require Tma64 (eIF2D), Tma20 (MCT-1), and Tma22 (DENR). However, it remains unclear how these Tma proteins cause 40S removal and control reinitiation of downstream translation. Here we used a 40S ribosome footprinting strategy to directly observe intermediate steps of ribosome recycling in cells. Deletion of the genes encoding these Tma proteins resulted in broad accumulation of unrecycled 40S subunits at stop codons, directly establishing their role in 40S recycling. Furthermore, the Tma20/Tma22 heterodimer was responsible for a majority of 40S recycling events while Tma64 played a minor role. Introduction of an autism-associated mutation into TMA22 resulted in a loss of 40S recycling activity, linking ribosome recycling and neurological disease.
Collapse
Affiliation(s)
- David J Young
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Sezen Meydan
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
- Postdoctoral Research Associate Training Program, National Institute of General Medical Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Nicholas R Guydosh
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.
| |
Collapse
|
36
|
Gaikwad S, Ghobakhlou F, Young DJ, Visweswaraiah J, Zhang H, Hinnebusch AG. Reprogramming of translation in yeast cells impaired for ribosome recycling favors short, efficiently translated mRNAs. eLife 2021; 10:e64283. [PMID: 33764298 PMCID: PMC7993997 DOI: 10.7554/elife.64283] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 03/04/2021] [Indexed: 12/21/2022] Open
Abstract
In eukaryotes, 43S preinitiation complex (PIC) formation is a rate-determining step of translation. Ribosome recycling following translation termination produces free 40S subunits for re-assembly of 43S PICs. Yeast mutants lacking orthologs of mammalian eIF2D (Tma64), and either MCT-1 (Tma20) or DENR (Tma22), are broadly impaired for 40S recycling; however, it was unknown whether this defect alters the translational efficiencies (TEs) of particular mRNAs. Here, we conducted ribosome profiling of a yeast tma64∆/tma20∆ double mutant and observed a marked reprogramming of translation, wherein the TEs of the most efficiently translated ('strong') mRNAs increase, while those of 'weak' mRNAs generally decline. Remarkably, similar reprogramming was seen on reducing 43S PIC assembly by inducing phosphorylation of eIF2α or by decreasing total 40S subunit levels by depleting Rps26. Our findings suggest that strong mRNAs outcompete weak mRNAs in response to 43S PIC limitation achieved in various ways, in accordance with previous mathematical modeling.
Collapse
Affiliation(s)
- Swati Gaikwad
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Fardin Ghobakhlou
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - David J Young
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of HealthBethesdaUnited States
| | - Jyothsna Visweswaraiah
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Hongen Zhang
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Alan G Hinnebusch
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| |
Collapse
|
37
|
Wei J, Fang D. Endoplasmic Reticulum Stress Signaling and the Pathogenesis of Hepatocarcinoma. Int J Mol Sci 2021; 22:ijms22041799. [PMID: 33670323 PMCID: PMC7918477 DOI: 10.3390/ijms22041799] [Citation(s) in RCA: 170] [Impact Index Per Article: 56.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 02/05/2021] [Accepted: 02/08/2021] [Indexed: 12/12/2022] Open
Abstract
Hepatocellular carcinoma (HCC), also known as hepatoma, is a primary malignancy of the liver and the third leading cause of cancer mortality globally. Although much attention has focused on HCC, its pathogenesis remains largely obscure. The endoplasmic reticulum (ER) is a cellular organelle important for regulating protein synthesis, folding, modification and trafficking, and lipid metabolism. ER stress occurs when ER homeostasis is disturbed by numerous environmental, physiological, and pathological challenges. In response to ER stress due to misfolded/unfolded protein accumulation, unfolded protein response (UPR) is activated to maintain ER function for cell survival or, in cases of excessively severe ER stress, initiation of apoptosis. The liver is especially susceptible to ER stress given its protein synthesis and detoxification functions. Experimental data suggest that ER stress and unfolded protein response are involved in HCC development, aggressiveness and response to treatment. Herein, we highlight recent findings and provide an overview of the evidence linking ER stress to the pathogenesis of HCC.
Collapse
|
38
|
DENR promotes translation reinitiation via ribosome recycling to drive expression of oncogenes including ATF4. Nat Commun 2020; 11:4676. [PMID: 32938922 PMCID: PMC7494916 DOI: 10.1038/s41467-020-18452-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 08/14/2020] [Indexed: 12/19/2022] Open
Abstract
Translation efficiency varies considerably between different mRNAs, thereby impacting protein expression. Translation of the stress response master-regulator ATF4 increases upon stress, but the molecular mechanisms are not well understood. We discover here that translation factors DENR, MCTS1 and eIF2D are required to induce ATF4 translation upon stress by promoting translation reinitiation in the ATF4 5'UTR. We find DENR and MCTS1 are only needed for reinitiation after upstream Open Reading Frames (uORFs) containing certain penultimate codons, perhaps because DENR•MCTS1 are needed to evict only certain tRNAs from post-termination 40S ribosomes. This provides a model for how DENR and MCTS1 promote translation reinitiation. Cancer cells, which are exposed to many stresses, require ATF4 for survival and proliferation. We find a strong correlation between DENR•MCTS1 expression and ATF4 activity across cancers. Furthermore, additional oncogenes including a-Raf, c-Raf and Cdk4 have long uORFs and are translated in a DENR•MCTS1 dependent manner.
Collapse
|